\r\n\tAn important part of the book will consider electrodes (materials, configurations, contacts with biological matter) as responsible tools for the acquisition of bioimpedance data correctly. Implementations in wearable and implantable health monitors are the proposed book topics. Detecting of different pathogens by the aid of lab-on-chip (LoC) devices for point-of-care (PoC) and need-of-care (NoC) diagnostics is expected. Also, express analysis of biological matter (blood and other body fluids) is included. Electronics connected to electrodes for receiving the bioimpedance signals for further processing belongs to sensing techniques and will be considered.
\r\n\tDevelopment and application of software tools for information extracting from the acquired bioimpedance data, automatic identification of bioparticles and the decision making for diagnosing and treatment are very welcome chapters in the present book.
UTI affects approximately 150 million people worldwide, which is most common infection with female predominance [1]. Around 15–25% hospitalized patients receiving indwelling urinary catheter develops CAUTI with prolonged catheterization and in among 40% nosocomial UTI, 80% is due to CAUTI [2]. CAUTI causes about 20% of episodes of health-care acquired bacteraemia in intensive care facilities and over 50% in long term care facilities [3]. The microbiology of biofilm on an indwelling catheter is dynamic with continuing turnover of organisms in the biofilm. Patients continue to acquire new organisms at a rate of about 3–7%/day. In long term catheterization that is by the end of 30 days CAUTI develops in 100% patients usually with 2 or more symptoms or clinical sign of haematuria, fever, suprapubic or loin pain, visible biofilm in character or catheter tube and acute confusion all state [4]. In CAUTI the incidence of infection is Escherichia coli in 24%, Candida in 24%, Enterococcus in 14% Pseudomonas in 10%, Klebsiella in 10% and remaining part with other organisms [5]. Bacteraemia occurs in 2–4% of CAUTI patients where case fatality is three times higher than nonbacteremic patients [6]. Adhesions in bacteria initiate attachment by recognizing host cell receptors on surfaces of host cell or catheter. Adhesins initiate adherence by overcoming the electrostatic repulsion observed between bacterial cell membranes and surfaces to allow intimate interactions to occur [7]. A biofilm is an aggregate of micro-organisms in which cells adhere to each other on a surface embedded within a self-produced matrix of extracellular polymeric substance [8]. In biofilm micro-organisms growing in colonies within an extra-cellular mucopolysaccharide substance which they produce. Tamm-Horsfall protein and magnesium and calcium ions are incorporated into this material. Immediately after catheter insertion, biofilm starts to form and organisms adhere to a conditioning film of host proteins along the catheter surface. Both the inner and outer surfaces of catheter are involved. In CAUTI biofilms are initially formed by one organism but in prolonged Catheterization multiple bacteria’s are present. In biofilm main mass is formed by extra cellular polymeric substance (EPS) within which organisms live. So there are three layers in biofilm, where deeper layer is abiotic, than environmental zone and on surface biotic zone [9]. Growth of bacteria in biofilms on the inner surface of catheters promotes encrustation and may protect bacteria from antimicrobial agents and the consequence is more drug resistance of biofilm organisms. When antibiotic treatment ends the biofilm can again shed bacteria, resulting recurrent acute infection. The patients may present as asymptomatic bacteriuria or symptomatic. In symptomatic bacteriuria patient present with fever, suprapubic or costovertebral angle tenderness, and systemic symptoms such as altered mentation, hypotension, or evidence of a systemic inflammatory response syndrome. In asymptomatic CAUTI diagnosis is made with presence of 105 cfu/mL of one bacterial species in a single catheter urine specimen [10]. In symptomatic CAUTI bacteriological criteria is present with clinical symptoms.
It is recommended that urine specimens be obtained through the catheter port using aseptic technique or, if a port is not present, puncturing the catheter tubing with a needle and syringe in patients with short term catheterization [11]. In long term indwelling catheterization, the ideal method of obtaining urine for culture is to replace the catheter and collect the specimen from the freshly placed catheter. In a symptomatic patient, this should be done immediately prior to initiating antimicrobial therapy. Culture specimens from the urine beg should not be obtained [10, 12]. Urine sample can be collected from suprapubic puncture also. Biofilm can be cultured from the catheter, for this swab is taken from inner side of catheter.
Catheter Associated Asymptomatic Bacteriuria (CA-ASB) is diagnosed when one or more organisms are present at quantitative counts ≥105 cfu/mL from an appropriately collected urine specimen in a patient with no symptoms [13]. Lower quantitative counts may be isolated from urine specimens prior to ≥105 cfu/mL being present, but these lower counts likely reflect the presence of organisms in biofilm forming along the catheter, rather than bladder bacteriuria [14]. Thus, it is recommended that the catheter be removed and a new catheter inserted, with specimen collection from the freshly placed catheter, before antimicrobial therapy is initiated for symptomatic infection [13]. In biofilm culture, most biofilm contains mixed bacterial communities meaning polymicrobial colonization.
Patients who remain catheterized without having antimicrobial therapy and who have colony counts ≥10 2 cfu/mL (or even lower colony counts), the level of bacteriuria or candiduria uniformly increases to >105 cfu/mL within 24–48 h [14]. Given that colony counts in bladder urine as low as 102 cfu/mL are associated with symptomatic UTI in non-catheterized patients [15], untreated catheterized patients and those who have colony counts ≥102 cfu/mL or even lower, the level of bacteriuria or candiduria uniformly increases to >105 cfu/mL within 24–48 h [10, 16]. Colony counts as low as 102 cfu/mL in bladder urine may be associated with symptomatic UTI in non-catheterized patients. Whereas low colony counts in catheter urine specimens are likely to be contaminated by periurethral flora, and the colony counts will increase rapidly if untreated. Low colony counts in catheter urine specimens are also reflective of significant bacteriuria in patients with intermittent catheterization [14].
Pyuria is usually present in CA-UTI, as well as in CA-ASB. The sensitivity of pyuria for detecting infections due to enterococci or yeasts appears to be lower than that for gram-negative bacilli. Dipstick testing for nitrites and leukocyte esterase was also shown to be unhelpful in establishing a diagnosis in catheterized patients hospitalized in the ICU [17].
It is the most common cause of CAUTI in 24–60% patients [5, 18]. In CAUTI the source of this organism is usually patients own colonic flora. E. coli is large and diverse group of bacteria found in environment, foods and intestine of human and animal. Among many species of E. coli only a few causes disease in human being. It is beneficial in that it prevents the growth and proliferation of other harmful species of bacteria. Even it plays an important role in current biological engineering.
E. coli was discovered in 1885 by Theodor Escherich, German bacteriologist, is gram negative rod, lactose fermenter, composed of one circular chromosome which is common facultative anaerobes in colon and farces of human. Distribution is diverse and most of them are harmless belonging to genus Escherichia. Harmful species causes infection of urinary tract, gastrointestinal tract, respiratory system and rarely bacteraemia and septicemia. Phylogenetic analysis of E. coli showed majority of the strains responsible for UTI belongs to the phylogenetic group B2 and D, while in smaller percentage belong to A and B1 [19].
It has three antigens O-cell was antigen, H- flagella antigen and k- Capsular antigen. It has pili—a capsule, fimbriae, endotoxins and exotoxins also. Uropathogenic E. coli use P fimbriae (pyelonephritis-associated pili) to bind urinary tract endothelial cells. Vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae and around 73% in E. coli causing CAUTI [20]. In UPEC fimbrial genes are ygiL, yadN, yfcV, and c2395 [21]. Pathogenesis of CAUTI initiated with UPEC colonization in periurethral and vaginal areas. Then it ascends to bladder lumen and grows as planktonic cells in urine. Sequentially adherence to bladder epithelium, then biofilm formation and invasion with replication and kidney colonization and finally bacteremia [22] (Figure 1).
Gram stain picture and morphology of E. coli. Adapted from CCBC faculty web. BIOL 230 Lab Manual: gram stain of E. coli and infection landscapes: Escherichia coli. http://faculty.ccbcmd.edu/courses/bio141/labmanua/lab16/gramstain/gnrod.html.
Diagnosis of E. coli infection is simple, by isolation and laboratory identification of bacterium from urine or biofilm. Laboratory diagnosis by culture of specimen—urine or catheter biofilm in blood agar, MacConkey’s agar or eosin-methylene blue agar (which reveal lactose fermentation). Immunomagnetic separation and specific ELISA, latex agglutination tests, colony immunoblot assays, and other immunological-based detection methods are other ways for diagnosis of E. coli.
Proteus species, member of the Enterobacteriaceae family of gram-negative bacilli are distinguishable from most other genera by their ability to swarm across an agar surface [23, 24]. Proteus species are most widely distributed in environment and as other enterobacteriaceae, this bacteria is part of intestinal flora of human being [25, 26]. Proteus also found in multiple environmental habitats, including long-term care facilities and hospitals. In hospital setting, it is not unusual for proteus species to colonize both the skin and mucosa of hospitalized patient and causing opportunistic nosocomial infections. It is one of the common causes of UTI in hospitalized patients undergoing urinary catheterization [26, 27].
UTIs are the most common manifestation of Proteus infection. Proteus infection accounts for 1–2% of UTIs in healthy women and 5% of hospital acquired UTIs. Catheters associated UTI have a prevalence of 20–45%. Proteus mirabilis causes 90% of proteus infection and proteus vulgaris and proteus penneri also isolated from long-term care facilities and hospital and from patients with underlying disease or specialized care. Most common age group is 20–50 years. More common in female group and the ratio between male female begins to decline after 50 years. UTI in men younger than 50 are usually caused by urologic abnormalities. Patients with recurrent infections, those with structural abnormalities of the urinary tract, those who have had urethral instrumentation or catheterization have an increase frequency of infection caused by proteus species [28].
Proteus mirabilis produces an acidic capsular polysaccharide which was shown from glycose analysis, carboxyl reduction, methylation, periodate oxidation and the application high resolution nuclear magnetic resonance techniques. Proteus species possess an extracytoplasmic outer membrane, a common feature shared with other gram-negative bacteria. Infection depends upon the interacting organism and the host defense mechanism. Various component of the membrane interplay with the host to determine virulence. Virulence factors associated with adhesion, motility, biofilm formation, immunoavoidance, nutrient acquisition and as well as factors that cause damage to the host [29, 30] (Figure 2).
Gram stain picture and morphology of Proteus. Adapted from CCBC faculty web. BIOL 230 Lab Manual: gram stain of Proteus mirabilis and Proteus vulgaris bacteria (SEM) | Macro & Micro: Up Close and Personal | Pinterest | Microbiology, Bacteria shapes and Fungi. https://www.pinterest.com › pin.
Certain virulence factors such as adhesin, motility and biofilm formation have been identified in Proteus species that has a positive correlation with risk of infection. After attachment of Proteus with urothelial cells, interleukin 6 and interleukin 8 secreted from the urothelial cells causes apoptosis and mucosal endothelial cell desquamation. Urease production of proteus also augments the risk of UTI. Urease production, together with the presence of bacterial motility and fimbriae or pili, as well as adhesins anchored directly within bacterial cell membrane may favor the upper urinary tract infection. Once firmly attached on the uroepithelium or catheter surface, bacteria begin to phenotypically change, producing exopolysaccharides that entrap and protect bacteria. These attached bacteria replicate and form microcolonies that eventually mature into biofilms [31, 32]. Once established, biofilms inherently protect uropathogens from antibiotic and the host immune response [33, 34]. Proteus mirabilis as with other uropathogens is capable of adapting to the urinary tract environment and acquiring nutrients. And this is accomplished by the production of degradative enzymes such urease and proteases, toxins such as Haemolysin Hpm A and iron nutrient acquisition proteins.
The infection with Proteus can be diagnosed by taking a urine sample for microscopy and culture which is sufficient in most of the cases except in few cases where advanced diagnostic tools are used. If the urine is alkaline, it is suggestive of infection with Proteus sp. The diagnosis of Proteus is made on swarming motility on media, unable to metabolized lactose and has a distinct fishy door. Ultrasound or CT scan to identify renal stone (Struvite stone) or to visualized kidneys or surrounding structures. It will allow to exclude other possible problems, mimicking symptoms of urinary tract infection [35, 36].
Pseudomonas is a gram-negative bacteria belonging to the family Pseudomonadaceae and containing 191 validly described species [37]. Because of their widespread occurrence in water and plant seeds, the pseudomonas was observed in early history of microbiology. Pseudomonas is flagellated, motile, aerobic organism with Catalase and oxidase-positive. Pseudomonas may be the most common nuclear or of ice crystals in clouds, thereby being of utmost importance to the formation of snow and rain around the world [38]. All species of Pseudomonas are strict aerobes, and a significant number of organisms can produce exopolysaccharides associated with biofilm formation [39]. Pseudomonas is an opportunistic human pathogen that is especially adept at forming surface associated biofilms. Pseudomonas causes catheter associated urinary tract infection(CAUTIs) through biofilm formation on the surface of indwelling catheters, and biofilm mediated infection including ventilator associated pneumonia, infections related to mechanical heart valves, stents, grafts, sutures, and contract lens associated corneal infection [40].
Pseudomonas is third ranking causes nosocomial UTI about 12%, where E. coli remain on the top [41]. CAUTI is directly associated with duration of catheterization. Within 2–4 days of catheterization 15–25% patients develop bacteriuria [42].
Pseudomonas aeruginosa is a gram-negative, rod shaped, asporogenous and monoflagellated, noncapsular bacterium but many strains have a mucoid slime layer. Pseudomonas has an incredible nutritional versatility. Pseudomonas can catabolize a wide range of organic molecule including organic compounds such as benzoate. This, then make Pseudomonas a very ubiquitous microorganism and Pseudomonas is the most abundant organism on earth [43] (Figure 3).
Gram stain picture and morphology of Pseudomonas aeroginosa. Adapted from Science News. A new antibiotic uses sneaky tactics to kill drug-resistant Pseudomonas aeruginosa illustration and Pseudomonas Aeruginosa Stock Photos & Pseudomonas Aeruginosa Stock Images—Alams. https://www.alamy.com › stock-photo.
Pseudomonas is widely distributed in nature and is commonly present in moist environment of hospitals. It is pathogenic only when introduce into areas devoid of normal defense such as disruption of mucous membrane and skin, usage of intravenous or urinary catheters and neutropenia due to cancer or in cancer therapy. Its pathogenic activity depends on its antigenic structure, enzymes and toxins [44]. Among the enzymes Catalase, Pyocyanin, Proteases, elastase, haemolysin, Phospholipase C, exoenzyme S and T and endotoxin and endotoxin A play role in disease process and as well as immunosuppression. Pseudomonas can infect almost any organ or external site. Pseudomonas in invasive and toxigenic. It attached to and colonized the mucous membrane of skin. Pseudomonas can invade locally to produce systemic disease and septicemia. Pseudomonal UTs are usually hospital acquired and are associated with catheterization, instrumentation and surgery. These infections can involve the urinary tract through an ascending infection or through bacteriuria spread. These UTIs may be a source of bacteraemia or septicemia [45].
Identification of bacterium with microscopy is simple method of identification of pseudomonas. Culture and antibiotic sensitivity pattern can be done in most laboratory media commonly on blood agar or eosin-methylthionine blue agar. Pseudomonas has inability to ferment lactose and has a positive oxidase reaction. Fluorescence under UV light is helpful in early identification of colonies. Fluorescence is also used to suggest the presence of pseudomonas in wounds [46].
Urinary catheters are standard medical devices utilized in both hospital and nursing home settings are associated with a high frequency of catheter-associated urinary tract infections (CAUTI). The contribution of Klebsiella spp. in CAUTI is near about 7.7% [47].
Klebsiella pneumoniae is a gram-negative pathogenic bacterium, is part of the Enterobacteriaceae family. It has got polysaccharide capsule attached to the bacterial outer membrane, and it ferments lactose. Klebsiella species are found ubiquitously in nature, including in plants, animals, and humans. They are the causative agent of several types of infections in humans. It has a large accessory genome of plasmids and chromosomal gene loci. This accessory genome divides K. pneumoniae strains into opportunistic, hyper virulent, and multidrug-resistant groups [48] (Figure 4).
Gram stain picture and morphology of Klebsiella pneumonie. Adapted from studyblue.com. Microbio Lab Practical I—Microbiology 101 with Johnson at University of Vermont—StudyBlue. Study 368 Microbio Lab Practical I flashcards from Tess H. on StudyBlue and Klebsiella Pneumoniae Stock Photos and Pictures. Getty Images https://www.gettyimages.com › photos.
The source of Klebsiella causing CAUTI can be endogenous typically via meatal, rectal, or vaginal colonization or exogenous, such as via equipment or contaminated hands of healthcare personnel. They typically migrate along the outer surface of the indwelling urethral catheter, until they enter the urethra.
Migration of the Klebsiella along the inner surface of the indwelling urethral catheter occurs much less frequently, compared with along the outer surface Internal (intraluminal) bacterial ascension occurs by Klebsiella tend to be introduced when opening the otherwise closed urinary drainage system, ascend from the urine collection bag into the bladder via reflux, biofilm formation occurs.
A critical step in progression to CAUTI by Klebsiella is to adhere to host surfaces, which is frequently achieved using pili (fimbriae) [49]. Pili are filamentous structures extending from the surface of Klebsiella. They can be as long as 10 μm and between 1 and 11 nm in diameter. Among the two types of pili—type 1 (fim) pili and type 3 (mrk) pili, type 1 aids virulence by their ability to adhere with mucosal surfaces and type 3 pili strongly associated with biofilm production [50]. Both fim and mrk pili are considered part of the core genome [51]. It is thought that both types of pili play a role in colonization of urinary catheters, leading to CAUTI [52]. In addition to fim and mrk pili, a number of additional usher-type pili have been identified in Klebsiella with an average of ~8 pili clusters per strain. Based on varying gene frequencies, some of these appear to be part of the accessory genome. Immediately after catheterization Klebsiella starts biofilm production on the inner as well as outer surface of the catheter and on urothelium. Biofilm augments migration of Klebsiella into urethra and urinary bladder. Biofilm formation on the catheter surface by Klebsiella pneumoniae causes severe problem. Type 1 and type 3 fimbriae expressed by K. pneumoniae enhance biofilm formation on urinary catheters in a catheterized bladder model that mirrors the physicochemical conditions present in catheterized patients. These two fimbrial types does not is expressed when cells are grown planktonically. Interestingly, during biofilm formation on catheters, both fimbrial types are expressed, suggesting that they are both important in promoting biofilm formation on catheters [53]. The biofilm life cycle illustrated in three steps: initial attachment events with inert surfaces type 1 and type 3 fimbriae encoded by the mrk ABCDF gene cluster within K. pneumoniae promotes biofilm formation [54, 55]. Detachment events by clumps of Klebsiella or by a ‘swarming’ phenomenon within the interior of bacterial clusters, resulting in so-called ‘seeding dispersal’.
Modifiable risk factor are prolonged catheterization, lack of adherence to aseptic catheter care, insertion of the indwelling urethral catheter in a location other than an operating room, presence of a urethral stent, feecal incontinence. Non-modifiable risk factor—renal disease (i.e., serum creatinine >2 mg/dL), diabetes mellitus, older age (i.e., age > 50 years old), female sex, malnutrition and severe underlying illness [53]. For infection several virulence factors such as surface factors (fimbriae, adhesins, and P and type 1 pili) and extracellular factors toxins, siderophores, enzymes, and polysaccharide coatings are necessary for initial adhesion with colonization of host mucosal surfaces for tissue invasion overcoming the host defense mechanisms, and causing chronic infections [55].
Diagnosis of klebsiella infection is by isolation and laboratory identification of bacterium from urine or biofilm. Laboratory diagnosis can be done by culture of specimen—urine or catheter biofilm in blood agar, MacConkey’s agar. Specific ELISA, latex agglutination tests, PCR and other immunological-based detection methods are sophisticated alternatives for diagnosis of klebsiella. Determination of a gene on capsule of Klebsiella is rapid and simple method for the determination of the K types of most K. pneumoniae clinical isolates [56].
Enterobacter species, particularly Enterobacter cloacae and Enterobacter aerogenes, are important nosocomial pathogens responsible for about 1.9–9% CAUTI, rarely causes bacteremia [57, 58]. Enterobacter cloacae exhibited the highest biofilm production (87.5%) among isolated pathogens [53].
Enterobacter bacteria are motile, rod-shaped cells, facultative anaerobic, non-spore-forming, some of which are encapsulated belonging to the family Enterobacteriaceae. They are important opportunistic and multi-resistant bacterial pathogens. As facultative anaerobes, some Enterobacter bacteria ferment both glucose and lactose as a carbon source, presence of ornithine decarboxylase (ODC) activity and the lack of urease activity. In biofilms they secrete various cytotoxins (enterotoxins, hemolysins, pore-forming toxins. Though it is microflora in the intestine of humans, it is pathogens in plants and insects. Amp C β-lactamase production by E. cloacae is responsible for cephalosporin resistance. They possess peritrichous, amphitrichous, lophotrichous, polar flagella. E. aerogenes flagellar genes and its assembly system have been acquired in bloc from the Serratia genus [59] (Figure 5).
Gram stain picture and morphology of Enterobacter species. Adapted from Gram Stain Kit | Microorganism Stain | abcam.comAdwww.abcam.com/ and Science Prof Online. Gram-negative Bacteria Images: photos of Escherichia coli, Salmonella & Enterobacter and Enterobacter aerogenes | Gram-negative microorganism—HPV Decontamination | Hydrogen Peroxide Vapour—Bioquellhealthcare.bioquell.com › microbiology.
The most important test to document Enterobacter infections is culture. Direct gram staining of the specimen is also useful. In the laboratory, growth of Enterobacter isolates is occurs in 24 h or less; Enterobacter species grow rapidly on selective (i.e., MacConkey) and nonselective (i.e., sheep blood) agars.
Enterococci are gram-positive facultative anaerobic cocci, two species are common commensal organisms in the intestines of humans: Enterococcus faecalis (90–95%) and Enterococcus faecium (5–10%) [60]. Though normally a gut commensal, these organisms are commonly responsible for nosocomial infection of urinary tract, biliary tract and blood, particularly in intensive care units (ICU) [61]. E. coli is usually the most frequent species isolated from bacteremic catheter associated urinary tract infections (CAUTI). However, Enterococcus spp. (28.4%) and Candida spp. (19.7%) were also reported to be most common [62]. In another study, E. coli was found the commonest (36%) followed by Enterococcus spp. (25%), Klebsiella species (20%) and Pseudomonas spp. (5%) [63].
The most important cause of bacteriuria is the formation of biofilm along the catheter surface [64]. Enterococcus is gram positive bacteria often found in pairs or short chains. Broadly, Enterococcus is in two groups—faecalis and non-faecalis (E. gallinarum and E. casseliflavus). Enterococcus faecalis formerly classified as part of the group D Streptococcus is a gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals, survive harsh environmental conditions including drying, high temperatures, and exposure to some antiseptics [65]. E. faecalis has the important characteristics of complex set of biochemical reactions, including fermentation of carbohydrates, hydrolysis of arginine, tolerance to tellurite, and motility and pigmentation. Presence of the catheter itself is essential for E. faecalis persistence in the bladder, E. faecalis depends on the catheter implant for persistence via an unknown mechanism that more than likely involves its ability to produce biofilms on the silicone tubing and immune-suppression [66].
E. faecalis produce a heteropolymeric extracellular hair-like fimbrial structure called the endocarditis- and biofilm-associated pilus-Ebp, having three components the organelle (EbpC), a minor subunit that forms the base of the structure (EbpB) and a tip-located adhesin (EbpA) [67]. EbpA is responsible for adhesion in urothelial and catheter surface for biofilm production (Figure 6).
Morphology of Enterococcus. Adapted from Science Photo Library/Alamy Stock Photo Image ID: F6YBC3.
Urine sample and biofilm microscopy can identify this gram positive organism. Culture yields the growth of E. faecalis in appropriate media. Advanced diagnostic methods like immunological-based detection methods and PCR are rarely needed for diagnosis.
One of the common causes of catheter associated urinary tract infection is fungal infection. Bacterial infections are accounted for 70.9% of catheter associated urinary infection. E. coli is the most commonly isolated organism (41.6%) whereas fungal infections are accounted for 16.6% and mixed fungal and bacterial infections accounted for 12.5% [68]. The National nosocomial infections surveillance (NNIS) data indicated that C. albicans caused 21% of catheter-associated urinary tract infections, in contrast to 13% of non-catheter-associated infections [69]. In one study 24% of the cases showing fungal yeast growth. Candida spp. was the commonest. Non-albicans Candida (86%) isolated more commonly than Candida albicans (14%) [70]. Candida are commensals, and to be pathogenic, interruption of normal host defenses is crucial which is facilitated in conditions like immunocompromised states as AIDS, diabetes mellitus, prolonged broad spectrum antibiotic use, indwelling devices, intravenous drug use and hyperalimentation fluids [71]. Diabetes mellitus has been reported as the most common risk factor for fungal infection [72, 73]. The duration of catheterization is also an important risk factor as the duration increases the incidence of fungal infection is increased [74].
Candida albicans is an oval, budding yeast, which is a member of the normal flora of mucocutaneous membrane. Twenty species of Candida yeasts can cause in human infection but most common is Candida albicans. Sometimes it can gain predominance and can produce disease. Other candida species that can cause disease occasionally are Candida parapsilosis, Candida tropicalis and Candida krusei [75]. Although Candida albicans are common isolates in CAUTI, Candida tropicalis is increasingly reported in CAUTI [76]. The majority of Candida albicans infections are associated with biofilm formation on host or abiotic surfaces such as indwelling medical devices, which carry high morbidity and mortality [63, 77]. Several factors and activities contribute to the pathogenesis of this fungus which mediate adhesion to and invasion into host cells, which are in sequences are the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes [78] (Figure 7).
Morphology of Candida albicans. Adapted from biomedik8888, Aug 24, 2011. http://www.BioMedik.com.au3.
Urine and materials removed from catheter are needed. Microscopic examinations of gram-stained specimen showed pseudohyphae and budding cells. Culture on Sabouraud’s agar at room temperature and at 37°C showed typical colonies and budding pseudomycelia [79].
It is facultative anaerobic bacilli gram-negative rod of Enterobacteriaceae family considered opportunistic human pathogen but not a component of human facial flora. It is capable of producing a pigment called prodigiosin, which ranges in color from dark red to pale pink. It is ubiquitously spent in nature and has preference for damp conditions. Though previously known as nonpathogenic, but since 1970s it is associated with multi drug resistant infection due to presence of R factor—a plasmid. A study in Japan showed 6.8% incidence of UTI with this organism [80]. It also causes bacteraemia rarely. Diagnosis is confirmed by culture of the urine specimen or catheter biofilm. Automated bacterial identification systems and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is the other modality for diagnosis of serratia as well as other enterobacteriaceae [81].
This non-fermentative gram-negative rod discovered as plant growth-promoting bacterium and potential biocontrol agent against plant pathogens. Infection with this uncommon organism in CAUTI occurs in combination with commonest bacteria E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. D. tsuruhatensis and E. coli coexist and tend to co-aggregate over time and also cooperate synergistically [82]. D. tsuruhatensis metabolized citric acid more rapidly leaving more uric acid available in the medium to be used by E. coli for dynamic growth of both organisms. Identification of this organism is not confirmatory with culture, so molecular methods are more reliable [83].
Achromobacter denitrificans is gram negative bacterium formerly known as Alcaligenes denitrificans. Infection with this organism predominantly observed in elderly patients with predisposing factors as urological abnormalities, malignancies and immune-suppression. Rarely it causes bacteraemia. This bacterium has high level of antibiotic resistance [84].
In polymicrobial biofilm, Achromobacter xylosoxidans cohabits with common organisms E. coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Diagnosis is by bacterial culture and molecular methods.
Staphylococci (methicillin-sensitive Staphylococcus aureus [MSSA] and methicillin-resistant S. aureus [MRSA], Staphylococcus saprophyticus. These are the common gram positive bacteria usually responsible for skin and soft tissue infections but rarely cause CAUTI and bacteraemia [85].
The incidence of Staphylococcal UTI as well as CAUTI is increasing and the organisms carry wide variety of multidrug-resistant genes on plasmids, which augment spread of resistance among other species [86].
Diagnosis is easy, gram stain of the sample, culture is sufficient. Advanced techniques rarely needed (Figure 8).
Morphology of Staphylococcus aureus. Adapted from abcam.comAdwww.abcam.com/ pharmacist-driven intervention improves care of patients with S aureus Bacteremia/Staph aureus. Nebraska Medicine https://asap.nebraskamed.com.
CAUTI is one of the most nosocomial Infection worldwide resulting from rational as well as sometimes irrational use of indwelling urinary catheter. Cause of CAUTI is formation of pathogenic biofilm commonly due to UPEC, Proteus, Klebsiella, Pseudomonas, Enterobacter rarely Candida and other uncommon opportunistic organisms. CAUTI has got high impact on morbidity and mortality as biofilm producing organisms are more antibiotic resistant. Antibiotic resistance is a global problem. Early detection of CAUTI is simple by examination of urine and catheter biofilm with microscopy as well as culture with antibiogram. It is easy and cost effective with early diagnosis and treatment for good clinical outcome. Advanced and sophisticated methods like Immunomagnetic separation, specific ELISA, colony immunoblot assays and PCR for diagnosis of CAUTI is seldom necessary.
Melanoma arises through the accumulation of genetic aberrations in melanocytes which lead to uncontrolled cellular proliferation, resistance to apoptosis, and escape from immune surveillance. Melanoma has the potential to metastasize distantly through hematologic and lymphatic channels. When distant spread is present, the melanoma is classified as stage IV. The American Joint Committee on Cancer (AJCC) eighth edition subcategorizes stage IV melanoma into four prognostic subgroups with the worst prognostic group (stage IV M1d) defined by the presence of brain metastases [1]. Melanoma is the third most common type of cancer to metastasize to the brain following breast and lung cancer. It is estimated that 10–40% of patients with stage IV melanoma eventually develop clinically detectable brain metastases [2]. In autopsy series, a high incidence of subclinical metastasis is noted as over 50% of patients have brain metastases [2].
\nBrain metastases can lead to morbidity with the development of seizures, cerebral edema, and neurologic symptoms reflective of the part of the brain involved. However, several retrospective analyses have shown that the majority of patients with brain metastases are asymptomatic [2]. While metastases can develop in any part of the brain, the incidence is not evenly distributed. A study evaluating the location of 115 brain metastases showed that 43.5% were located in the frontal lobe with only 8.6% in the cerebellum and less than 1% in the hippocampus [3]. Similarly, a retrospective single center analysis of 6064 brain metastases in 632 cancer patients revealed that fewer than 1% of the metastases develop in the hippocampus, while the distribution is highest in the frontal lobe (31.6%) [4].
\nThe prognosis for patients with melanoma metastatic to the brain is very poor with an historical median overall survival of approximately 4 months [5]. However, prognosis is heterogeneous with a small subset of patients demonstrating greater than 3-year survival despite the development of brain metastases. A retrospective review of 702 patients with melanoma-related brain metastases identified a small subset of patients who survived greater than 3 years. These patients were largely categorized by the presence of an isolated brain metastasis that was treated surgically [5].
\nSeveral retrospective studies have attempted to associate clinical and pathological characteristics with the development of brain metastases and with the outcome following the development of brain metastasis. A review of clinical features and survival outcome in melanoma patients who enrolled in any of 12 clinical trials at a single cancer center identified factors prognostic for overall survival [6]. About 44% of 743 chemotherapy naive melanoma patients developed brain metastases with the median overall survival following diagnosis of brain metastases being only 4.3 months. Age at the time of diagnosis of brain metastases did not predict for survival outcome. However, the year of diagnosis was prognostic as patients diagnosed prior to 1996, the midpoint for inclusion of these patients, had worse survival than patients diagnosed after the start of 1996 (4.14 months vs. 5.92 months, p = 0.01). While prognosis has improved over time, survival outcomes remain very poor. Other prognostic factors included the number of brain metastases with a median survival for patients with one to three metastases of 5.92 months as opposed to 3.52 months for those with more than three brain metastases (HR 1.57, p = 0.001). The presence of leptomeningeal involvement conferred an even worse prognosis with a median overall survival of only 1.2 months. The development of brain metastases after receiving systemic therapy for extracranial metastases conferred worse overall survival compared to developing the brain metastases before or synchronous to extracranial metastases (HR 1.78, p < 0.0001). Therefore, in multivariate analysis, the year of diagnosis, number of parenchymal brain metastases, and timing of metastases relative to extracranial metastases were significantly associated with overall survival. Another retrospective analysis of 49 patients with melanoma metastatic to the brain identified as part of a melanoma database collected from 1998 to 2012 associated survival to the presence or absence of symptoms, number of parenchymal brain lesions (one vs. two or more), and response to chemotherapy [2]. A multivariate analysis of 89 melanoma patients from a single institution who developed brain metastases and who were part of a larger prospectively accrued cohort of 900 melanoma patients revealed that the presence of neurologic symptoms and extracranial metastases predicted for worsened survival [7].
\nThe modality used to treat brain metastases may reflect prognosis. The median survival of 686 patients with melanoma and cerebral metastases treated at the Sydney Melanoma Unit between 1985 and 2000 was 8.9, 8.7, 3.4, and 2.1 months, respectively, in patients treated with surgery plus postoperative radiotherapy, surgery alone, radiotherapy alone, and supportive care alone [8]. While outcomes differed in patients receiving surgery and/or radiotherapy compared to best supportive care, the differences may reflect patient selection based on performance status, extent of extracranial metastases, comorbidities, and number, size, and location of brain metastases. These features impact the decision to recommend surgery or radiation therapy. Furthermore, the size, location, and number of metastases impact the ability to perform stereotactic radiosurgery as opposed to whole brain radiation therapy.
\nOverall survival of stage IV melanoma patients also is determined by the effectiveness of systemic therapy. Systemic treatment options have improved over the past decade through the development of efficacious immunotherapies and molecularly targeted approaches translating into improvements in survival. Prior to 2011, the only two systemic therapies Food and Drug Administration (FDA) approved for the treatment of stage IV melanoma were the cytotoxic chemotherapy dacarbazine (DTIC) and the cytokine immunotherapy high-dose interleukin-2 (HD-IL2). DTIC is an intravenously administered alkylating agent that confers responses in 5–20% of stage IV melanoma patients but the responses are largely partial and not durable [9]. Treatment with HD-IL2 confers a 16% response rate with 5% of patients developing complete durable responses [10]. The potential for HD-IL2 to cause capillary leak syndrome and cerebral edema limits the ability to use this treatment in patients with brain metastases. Neither HD-IL2 nor DTIC have been shown in randomized studies to confer overall survival benefit.
\nTemozolomide is an oral alkylating agent that is metabolized to MTIC the same active agent that dacarbazine is metabolized to. Treatment of stage IV melanoma patients randomized to treatment with dacarbazine or temozolomide showed equivalency in terms of response rate and survival [11]. Temozolomide has better penetrance of the central nervous system. A retrospective analysis comparing CNS relapse rate in patients who responded to treatment with temozolomide versus dacarbazine showed that temozolomide-treated patients had significantly fewer CNS relapses [12]. This suggests that temozolomide may prevent development of brain metastases in melanoma patients. To assess efficacy of temozolomide in treating brain metastases in melanoma patients where the metastases did not require immediate radiation therapy, a phase II study was performed treating 151 patients with temozolomide at dose of 150 milligrams per meter squared (mg/m2) per day for 5 days in row every 28 days. Among the 117 patients who did not receive prior systemic therapy, the response rate was 7%, while 29% had stabilization of the brain metastases. Of the 34 patients who received prior systemic therapy, only 1 patient responded and 6 patients developed stable disease in the brain [13]. Therefore, while temozolomide demonstrates efficacy in treating melanoma brain metastases, the benefit is limited and seen only in a small subset of patients.
\nAn improved mechanistic understanding of the positive and negative regulation of the immune system through multiple immune-mediated checkpoints has led to the development of more efficacious treatment for stage IV melanoma patients. Since 2011, the FDA has approved for treatment of stage IV melanoma an inhibitor of the negative regular cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), ipilimumab, and two inhibitors of the negative regulator programmed death-1 (PD-1), nivolumab and pembrolizumab. Ipilimumab is administered intravenously at a dose of 3 milligrams per kilogram (mg/kg) every 3 weeks for a total of four doses. Nivolumab is administered intravenously at a flat dose of 240 mg intravenously every 2 weeks or 480 mg every 4 weeks. Pembrolizumab is administered at a dose of 200 mg every 3 weeks.
\nT-cell activation requires binding of the T-cell receptor to an antigen-derived amino acid sequence complexed to MHC molecules on antigen presenting cells. For T-cell activation, costimulatory interactions are necessary with binding of CD28 on the T-cell to B7 on the antigen presenting cell. CTLA-4 is expressed on T-cells and binds to B7 with higher affinity that CD28 leading to disruption of CD28-B7 interaction thereby dampening the immune response. Ipilimumab is a fully human IgG1 monoclonal antibody that binds to CTLA-4 in an inhibitory fashion enhancing T-cell priming and decreasing suppressor T-cell activity [14]. A phase III study that randomized previously treated stage IV melanoma patients to treatment with ipilimumab alone at a dose of 3 mg/kg intravenously every 3 weeks for four treatments, a peptide vaccine GP-100 alone, or the combination of ipilimumab plus the vaccine demonstrated a statistically significant improvement in overall survival following ipilimumab treatment [14]. The median overall survival was 10.1 months in the ipilimumab group as opposed to 6.4 months in the gp100 vaccine group (hazard ratio for death of 0.68; p-value < 0.001). A pooled analysis of long-term data from 12 phase II and phase III studies encompassing 1861 melanoma patients treated with ipilimumab showed a mean overall survival of 11.4 months with a survival rate at 3 years of 22% [15].
\nNivolumab and pembrolizumab are monoclonal antibodies which inhibit the activity of PD-1 leading to increased T-cell activity in the tumor microenvironment [16, 17]. PD-1 is expressed on the surface of tumor infiltrating T-cells and binds to PD-L1 which is aberrantly expressed on tumor cells leading to functional inhibition of the T-cells. Both of the PD-1 inhibitors confer 35–40% response rates and lead to significantly improved survival when compared to outcomes following ipilimumab treatment [18, 19]. The Keynote-006 phase III study randomized 834 melanoma patients to treatment with pembrolizumab or ipilimumab. Median overall survival with a median follow-up of 22.9 months was not reached in the pembrolizumab-treated patients as opposed to 16 months in the ipilimumab-treated patients (p = 0.0009). Twenty-four-month overall survival was 55 and 43% in the pembrolizumab and ipilimumab groups, respectively (p = 0.0009) [18].
\nCTLA-4 and PD-1 inhibitors modulate different parts of the immune system, and preclinical murine models demonstrate synergistic activity following concurrent CTLA-4 and PD-1 blockade [20]. The CheckMate 067 study randomized 945 advanced melanoma patients to placebo-controlled treatment with ipilimumab monotherapy, nivolumab monotherapy, or the combination of ipilimumab plus nivolumab [21]. Ipilimumab-treated patients received ipilimumab at dose of 3 mg/kg every 3 weeks for a total of four treatments. Nivolumab-treated patients were treated with 3 mg/kg nivolumab every 2 weeks. Patients receiving combination therapy were treated with ipilimumab at a dose of 3 mg/kg plus nivolumab 1 mg/kg every 3 weeks for a total of four doses and then nivolumab alone every 2 weeks at a dose of 3 mg/kg. Objective responses were noted in 58, 45, and 19% of combination therapy, nivolumab monotherapy- and ipilimumab monotherapy-treated patients, respectively. With a minimum 4 year follow-up, the median overall survival was not reached in the combination group, was 36.9 months in the nivolumab group, and was 19.9 months in the ipilimumab group.
\nInhibition individually or in combination of the CTLA-4 and PD-1 checkpoints leads to survival benefit for stage IV melanoma patients. However, the initial clinical trials excluded patients with untreated brain metastases. To determine the antimelanoma efficacy of these immune modulatory approaches in patients with untreated brain metastases, clinical trials were developed specifically enrolling melanoma patients with untreated brain metastases.
\nA phase II study of patients with melanoma and untreated brain metastases treated with ipilimumab showed intracranial responses in 8 of 51 (16%) of asymptomatic patients who did not need steroids and 1/21 (5%) of patients requiring steroids because of perimetastasis edema or neurologic symptoms related to the metastases. Median overall survival remained poor being 7 months for patients not needing steroids and 3.7 months for patients requiring steroids [22]. The overall survival assessment also reflects the time period when the study was conducted prior to availability of anti-PD-1 immunotherapies.
\nA single center phase II study treated 18 stage IV melanoma patients with at least 1 untreated or progressive brain metastasis between 5 and 20 mm in diameter and without associated neurologic symptoms to treatment with pembolizumab at a dose of 10 mg/kg every 2 weeks. Four of the patients (22%) developed a partial response in the brain. The responses were durable lasting at least 4 months, and at the time of data, cutoff was ongoing in all responders [23].
\nTo determine the intracranial efficacy of combined CTLA-4 and PD-1 blockade, a phase II multicenter study, CheckMate 204, treated melanoma patients who had at least one measurable nonirradiated brain metastasis with a diameter between 0.5 and 3 cm and with no associated neurologic symptoms to combined treatment with nivolumab and ipilimumab [24]. The primary endpoint was intracranial clinical benefit defined as complete or partial response or stable disease at 6 months. Brain metastases were felt to not need immediate resection or radiosurgery and patients did not receive steroid treatment for at least 10 days prior to treatment initiation. The nivolumab was administered at dose of 1 mg/kg and ipilimumab 3 mg/kg every 3 weeks for four doses followed by single agent nivolumab at dose of 3 mg/kg every 2 weeks until disease progression or prohibitive toxicity. With a median of 14 month follow-up, the rate of intracranial benefit in the 94 patients who were followed for at least 6 months was 56% with a 26% complete response rate and 30% partial response rate. About 2% of patients had intracranial stable disease that lasted greater than 6 months. About 64% of patients did not experience intracranial progression of brain metastases 6 months after treatment initiation. The extracranial clinical benefit rate was 56% similar to the intracranial rate. As expected, the combination immunotherapy treatment led to a 55% rate of high-grade toxicity felt related to the immunotherapy. Treatment-related adverse events involving the central nervous system were seen in 36% of patients and high-grade CNS toxicity developed in 7% of the patients. The most common treatment-related nervous system toxicity of any severity was headache affecting 22% of patients with 3% having severe headaches.
\nAdditional evidence that anti-PD-1 immunotherapy has efficacy in treating active brain metastases comes from the results of a phase II study conducted at four sites in Australia. Melanoma patients with asymptomatic brain metastases that did not receive prior localized treatment were randomized to systemic therapy with nivolumab or combined nivolumab plus ipilimumab blockade. Efficacy was appreciated in both cohorts with intracranial response rates of 20 and 46% seen in nivolumab alone versus combination therapy-treated patients, respectively [25].
\nTreatment of stage IV melanoma has improved not only through the use of immunotherapy but also through the use of molecular-targeted therapies. Approximately, 40% of melanomas select for an activating mutation in the protein BRAF which is a component of the mitogen-activated protein kinase (MAPK) signaling pathway. The MAPK signaling pathway is a cascade initiated by extracellular signals binding to cell membrane receptors activating RAS which then activated CRAF and BRAF leading to downstream activation of MEK and ERK. Greater than 90% of BRAF mutations in melanoma are activating hotspot mutations present at position 600 with the most common being a V600E mutation. Activation of BRAF leads to melanoma proliferation and survival due to enhanced signaling through the MAPK pathway. Three different combinations of BRAF plus MEK inhibitors (the BRAF inhibitors dabrafenib, vemurafenib, and encorafenib combined with the MEK inhibitors trametinib, cobimetinib, and binimetinib, respectively) are FDA approved for the treatment of unresectable melanoma expressing a V600E BRAF mutation [26, 27, 28]. Randomizing 947 previously untreated patients with unresectable melanoma to treatment with dabrafenib plus placebo or dabrafenib plus trametinib as part of an international phase III study demonstrated overall survival benefit favoring the dual inhibitor approach [29]. Treatment with dabrafenib monotherapy conferred a 53% response rate, while dabrafenib plus trametinib treatment led to a 69% response rate. Efficacy is limited by the development of resistance with median progression free survival being 8.8 and 11 months for patients treated with dabrafenib monotherapy or combination therapy, respectively. Two-year overall survival was 42% for patients treated with BRAF inhibition alone and improved to 51% for patients treated with concurrent BRAF and MEK inhibition [29]. Eligibility requirements for the trial required definitive treatment of any preexisting brain metastases with confirmed stability of at least 12 weeks. Patients with untreated or unstable brain metastases were excluded from enrollment.
\nTo determine the ability of combined BRAF and MEK inhibition to treat progressive brain metastases in patients with melanoma expressing a V600 BRAF mutation, a multicenter international phase II (COMBI-MB) study was performed which treated four cohorts with dabrafenib plus trametinib [30]. The four cohorts were: A. Patients with melanoma expressing a V600E BRAF mutation and with asymptomatic brain metastases, no prior localized therapy to the brain metastases, and an ECOG performance status 0 or 1. B. Patients with melanoma expressing a V600E BRAF mutation and asymptomatic brain metastases and an ECOG performance status 0 or 1 but who received prior localized therapy to the brain metastases. C. Patients with melanoma expressing a V600 D/K/R mutation and asymptomatic brain metastases and ECOG performance status of 0–1 with or without prior localized treatment of the brain metastases. D. Patients with melanoma expressing a V600 D.E/K/R BRAF mutation and with symptomatic brain metastasis and an ECOG performance status of 0, 1, or 2. The primary endpoint was investigator-assessed intracranial response in the first patient cohort. Intracranial response in the other three cohorts was a secondary endpoint. With a median follow-up of 8.5 months, the intracranial response rate in the 76 patients enrolled in cohort A was 58%. The intracranial response rates in the 16 patients enrolled in cohort B, 16 patients enrolled in cohort C, and 17 patients enrolled in cohort D were 56, 44, and 59%, respectively. Therefore, clinical benefit intracranially was appreciated in all four cohorts even in patients with worsened performance status (ECOG 2) and symptomatic brain metastases. Longer follow-up is needed to determine effects on survival and long-term intracranial metastases control rates.
\nWhile systemic therapies can lead to intracranial efficacy in a subset of metastatic melanoma patients, multimodality approaches may lead to further improvement in clinical outcome. A meta-analysis performed in April 2017 identified six retrospective studies which compared treatment with stereotactic radiotherapy alone to radiotherapy plus ipilimumab [31]. Of the 411 patients identified, 128 were treated with a combined radiotherapy and immunotherapy approach, while 283 received radiotherapy alone. Combination therapy significantly improved survival (HR 0.74, p = 0.04) without significantly increasing the incidence of adverse events. The authors conclude that combining stereotactic radiosurgery (SRS) is safe and effective treatment option.
\nGiven the survival benefits of initial immunotherapy treatment with a PD-1 inhibitor as opposed to ipilimumab in patients with melanoma who have brain metastases, one may expect that SRS plus a PD-1 inhibitor may incrementally improve intracranial response and survival compared to treatment with SRS plus ipilimumab. A study of patients who received SRS plus a PD-1 inhibitor had a median overall survival of 20.4 months as opposed to 7.5 months in patients treated with SRS plus CTLA-4 blockade [32]. A single institution retrospective study assessed the intracranial metastasis control rate in patients treated with SRS for melanoma brain metastases within 3 months of receiving treatment with anti-PD-1 immunotherapy, anti-CTLA-4 immunotherapy, BRAF plus MEK inhibitor targeted therapy, anti-BRAF monotherapy, or cytotoxic chemotherapy [33]. The 12-month distant melanoma metastasis control rates were 38, 21, 20, 8, and 5%, respectively. Local melanoma brain metastasis control rates were similar among the groups. Combining systemic therapy with SRS was overall well tolerated without significant increase in neurotoxicity. Multivariate analysis showed improved overall survival in patients treated with immunotherapy or BRAF targeted therapy when compared to those treated with cytotoxic chemotherapy.
\nTreatment of patients with melanoma brain metastases should be based upon a personalized treatment plan that may include multimodality approaches utilizing systemic therapy, surgery, and radiation therapy. The treatment approach will be impacted by multiple factors including but not limited to comorbidities, performance status, number, size, and location of brain metastases, CNS metastasis-related symptoms, steroid needs, prior therapy, the presence or absence of a BRAF mutation, and patient preference. Recent advances identifying immunomodulatory and BRAF-targeted therapies with intracranial efficacy have led to outcomes that are better than historically expected through the use of anti-PD-1 monotherapy, combined anti-CTLA-4 plus anti-PD-1 blockade, and if patients with a V600 BRAF mutation combined BRAF and MEK inhibition.
\nAdvisory Board Member for Seattle Genetics, Regeneron, Array Biopharma, EMD Serono, and Castle Biosciences. Consultant for Aspyrian Therapeutics.
\n“Scientific progress is fueled by collaboration. By democratizing the world’s scientific research, making it freely available to all, we want to inspire greater opportunity for collaboration, speed of discovery and scientific progress.”
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\\n\\nHumans in Space program aims to remove this barrier and pursue a model under which none of our authors will need to pay for publication and the editors will receive a budget for their editorial work.
\\n\\nWe are currently in the process of collecting sponsorship. If you have any ideas or would like to help sponsor the program, we’d love to hear from you. Contact: Natalia Reinic Babic at natalia@intechopen.com. All of our IntechOpen sponsors are in good company The research in past IntechOpen books and chapters have been funded / sponsored by:
\\n\\nOpen Access is in the heart of the Humans in Space program as it removes barriers and allows everyone to freely access the research published. However, open access publishing fees also pose a barrier to many talented authors who just can’t afford to pay.
\n\nHumans in Space program aims to remove this barrier and pursue a model under which none of our authors will need to pay for publication and the editors will receive a budget for their editorial work.
\n\nWe are currently in the process of collecting sponsorship. If you have any ideas or would like to help sponsor the program, we’d love to hear from you. Contact: Natalia Reinic Babic at natalia@intechopen.com. All of our IntechOpen sponsors are in good company The research in past IntechOpen books and chapters have been funded / sponsored by:
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