Escherichia coli is a famous Gram-negative bacillary bacterium that belongs to Enterobacteriaceae. It is either micro-biota innocent for human or pathogenic with arrays of diseases. The pathogenic E. coli can be assigned to intestinal (InPEC) or extraintestinal (ExPEC) with disease ranging from watery diarrhea to pulmonary distress. The most prevalent form of InPEC is enteropathogenic E. coli (EPEC), while the most prevalent ExPEC is uropathogenic E. coli (UPEC). The other InPEC includes Shiga toxin–producing (STEC), enteroaggregative (EAEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), diffusely adherent (DAEC) and adherent invasive E. coli (AIEC). ExPEC was implicated in cystitis, pyelonephritis, sepsis, respiratory tract infection, cervicovaginal infection (CVEC), meningitis (NMEC), otitis media, cholecystitis and wound infection. Antibiotic resistance is the challenging in world nowadays. Multidrug-resistant (MDR) Escherichia coli has become challenging with existing antibiotic options. E. coli pathogens have various virulence factors that determine their pathogenesis and antimicrobial resistance mechanisms. The rapid and ongoing spread of antimicrobial-resistant organisms threatens our ability to successfully treat a growing number of infectious diseases. It is well established that antibiotic use is a significant, and modifiable, driver of antibiotic resistance. The most commonly used antibiotic classes for InPEC and ExPEC were third-generation cephalosporin, carbapenem, fluoroquinolone and aminoglycosides. Actually, the most effective prescribed medication is one of the following: cefotaxime, ceftriaxone, ciprofloxacin, amikacin, gentamycin, levofloxacin and imipenem. Generally, according to our review for more than 100 local Iraqi studies among Iraqi provinces, the results revealed the resistance rate from highest to lowest as follows: cefotaxime (76.5%), ceftriaxone (75.9%), gentamycin (41.65%), ciprofloxacin (32.13%), amikacin (17.3%), levofloxacin (15%) and imipenem (5.14%). The resistance mechanisms may include genes encoding antibiotic-modifying enzymes like those of extended-spectrum beta-lactamases gene comprising: blaCTX-M, blaTEM, blaSHV, blaOXA, blaPER, blaVIM, blaIMP, blaNDM and blaAMPc. Efflux pumping includes AcrAB, while resistance to quinolone may be mediated by mutation among qnrA, qnrB, qnrD and qnrS. Resistance to aminoglycosides includes encoding to aminoglycoside-modifying enzymes like aac(6)-Ib, aph(3)-I, aph(3)-IIa, aph(3)-Ib, ant(3)-I, aac(3)-II and aac(3)-IV.
Part of the book: E. Coli Infections
Acinetobacter baumannii is one of the opportunistic bacteria firstly related with the hospital acquired infection influencing primarily to weakening the patient in the ICU. It is sometimes transferred to the patient by transient colonization of hands of the workers of healthcare, and persistence on eco-surfaces. Acinetobacter baumannii inhalation aerosolized through endo-tracheal suctioning of the ventilated patient is widespread among ventilator-related pneumonia (VAP). It is infections mainly associated with ventilator-related pneumonia (VAP), community Acquired Pneumonia (CAP), invasive bacterial infections (IBIs) and UTI (urinary tract infection). It is one of the prominent uropathogens problematic with antibiotic resistance especially carbapenem resistant Acinetobacter baumannii (CRAB). Their colonization of urinary tract and establishment of infection may attributed mainly to set of virulence factors like: Acinetobactin-assisted iron acquisition system, Bap (biofilm-related protein), phospholipase D, Ata (Acinetobacter trimeric autotransporter), chaperone-usher type pilus (Csu), OmpA (outer membrane protein A), and Plasminogen-binding protein (CipA). The common drugs used for treatment Acinetobacter baumannii infections involve polymyxins, glycylcyclines, tetracyclines, mono-bactams, fluoroquinolones, aminoglycosides, antipseudomonal carbapenems, antipseudomonal cephalosporins, and sulbactam. The rates of MDR isolation or also comprehensively the resistant Acinetobacter baumannii are significantly increased and so the combination of two or more (colistin, tigecycline, or colistin-rifampicin combination therapy) drugs is sometimes used to treat infections of MDR-AB. As a conclusion the Acinetobacter baumannii engagement in urinary tract infections attributed mainly to their adhesins, invasins and intrinsic antibiotic resistance.
Part of the book: Urinary Tract Infection and Nephropathy
Pseudomonas aeruginosa is Gram negative bacteria that can adapt to extreme environmental conditions and withstand to different antibacterial agents. It si responsible for arrays of infections both community and hospital acquired especially ICU infections. Respiratory tract infection, blood stream infection, wound infection, burn infection, and urinary tract infections ware top five P. aeruginosa infections. Additionally as an opportunistic bacteria, it may be associated with healthcare infections in intensive care units (ICUs), ventilator-associated pneumonia (VAP), central line-associated blood stream infections, surgical site infections, otitis media, and keratitis. P. aeruginosa can form biofilms as self-produced extracellular matrix to protects the cells from antibiotics and the host immune response. Antibiotic resistance was an prominent feature of this pathogen and can donate it one of the three resistance patterns: Multidrug (MDR), extensive drug (XDR) and pan drug resistance. It exploit many resistance mechanisms ranged from overexpression of drug efflux systems protein, modifying enzyme production, reducing the permeability and using shelters like biofilms.
Part of the book: Pseudomonas aeruginosa
S. Typhi is an enteric bacillus which belongs,to the genus Salmonella in the family Enterobacteriacaea and it is a multi–organs pathogen which inhibits the lymphatic tissues of the small intestine, liver, spleen, and blood stream of infected humans. S. Typhi has a mixture of features that make it an efficient pathogen. This species contains an endotoxin that is characteristic of Gram-negative organisms, as well as the virulence-enhancing Vi antigen. Many of the S. Typhi virulence factors are clustered in some areas of the chromosome known as Salmonella pathogenicity islands (SPI), such as adhesion, invasion, and toxin genes. A protein known as invasin that permits non-phagocytic cells is also produced and excreted by the bacterium., Where it is capable of intracellular living. The oxidative burst of leukocytes may also be inhibited, making innate immune reaction ineffective.
Part of the book: Salmonella spp
Urinary tract infections (UTI) are the most common bacterial infections affecting humans. Escherichia coli and Klebsiella pneumoniae were common enterobacteria engaged with community-acquired UTIs. Efflux pumps were vital resistance mechanisms for antibiotics, especially among enterobacteria. Overexpression of an efflux system, which results in a decrease in antibiotic accumulation, is an effective mechanism for drug resistance. The ATP-binding cassette (ABC) transporters, small multidrug resistance (SMR), and multidrug and toxic compound extrusion (MATE) families, the major facilitator superfamily (MFS), and the resistance-nodulation- cell division (RND) family are the five superfamilies of efflux systems linked to drug resistance. This chapter highlights the results of studying the prevalence of efflux pump genes among local isolates of E. coli and K. pneumoniae in Hilla City, Iraq. class RND AcrAB-TolC, AcrAD-TolC, and AcrFE-TolC genes detected by conventional PCR of E. coli and K. pneumoniae respectively. The result revealed approximately all studied efflux transporter were found in both E. coli and K. pneumoniae in different percentages. Biofilm formation were observed in 50(100%) of K. pneumoniae and 49(98%) of E. coli isolates were biofilm former and follow: 30(60%), 20(40%) were weak, 12(24%), 22(44%) were moderate and 7(14%) and 8(16%) were Strong biofilm former for E. coli and K. pneumoniae, respectively.
Part of the book: The Global Antimicrobial Resistance Epidemic
Noncoding RNA (ncRNA) includes short (miRNA) and long (lncRNA) that have important regulatory role in different biological processes. One of the important issue in which ncRNA involved is tumor induction and suppression. miRNA and lncRNA were vital players in many tumors including digestive system tumors. This study includes studying the role of 140 hsa-miR including miR-1 to miR-140 and their sponger lncRNA in esophageal and stomach cancers by 249 studies. The review revealed that each miR may play as oncogene only or tumor suppressor via upregulation and downregulation regulatory proteins in cell cycles and activation of physiological cascades. Some of miR have dual role in same type of tumor as oncogene and suppressive miR. Same thing is for lncRNA tacting as oncogenic via sponging some of miR when overexpressed to upregulate oncogenic protein or acting as suppression lncRNA when overexpressed to downregulate some oncogenic proteins activated by miR. The current review concludes the vital role of ncRNA (both miRNA and lncRNA) in some digestive system tumors as oncogene-promoting cancer viability, invasiveness, proliferation, and metastasis or as tumor suppressor inhibiting tumorigenicity or inducing apoptosis.
Part of the book: Recent Advances in Noncoding RNAs