Chapters authored
Escherichia coli O157:H7 and Its Effect on Human Health
Escherichia coli (E. coli) has many serotypes. The O157:H7 E. coli serotype is the most prominent serotype of enterohemorrhagic E. coli. It produces the Shiga toxin, which is one of the most important virulent factors discovered till today and has different subtypes with different antigenic and molecular traits. Consumption of contaminated water, milk or even eating an uncooked raw meat can cause bloody diarrhea that can end up in a life-threatening disease, such as hemolytic uremic syndrome (HUS). This is a condition that affects endothelial cells in the blood vessels and leads to thrombocytopenic purpura (TTP) that can cause blood clots formation in small blood vessels. The E. coli O157:H7 can be isolated from patient’s stool and be identified by serological tests such as enzyme-linked immunosorbent assay (ELISA) and immunoblotting methods. This special strain of E. coli can be used as a biological weapon, as it can be so dangerous and has the ability to spread easily form person to person.
Part of the book: Escherichia coli
UTI Caused by Staphylococcus saprophyticus
Coagulase-negative Staphylococci (CoNS) are one of the most frequently isolated bacteria in the clinical microbiology laboratory. These bacteria are normal inhabitants of human skin and mucous membranes; also, they have emerged as significant nosocomial pathogens. Staphylococcus saprophyticus is a Gram-positive bacterium well known for causing uncomplicated urinary tract infections in young sexually active females, responsible for complications including urinary tract infections, epididymitis, prostatitis, and acute pyelonephritis. CoNS can be divided into two groups based on susceptibility to novobiocin. The novobiocin-susceptible species include S. epidermidis, S. haemolyticus, S. hominins, S. lugdunensis, S. schleiferi, and the novobiocin-resistance species, including S. saprophyticus and S. xylosus. The acute uncomplicated UTI, including cystitis and pyelonephritis, is frequent in an immunocompetent nonpregnant female population, the second most common cause of community-acquired urinary tract bacterial infection in women after the Escherichia coli. S. saprophyticus is a part of the normal human flora which colonizes the rectum, urethra, cervix, and gastrointestinal tract. Bacterial colonization of the bladder and ureter epithelium occurs via several types of adhesin, including hemagglutinins with autolytic properties. Also, some strains can create and produce biofilms to increase their pathogenicity.
Part of the book: Urinary Tract Infections