Microbiology Notes By Sagar Aryal
Shiga toxin-producing Escherichia coli (STEC) The Shiga toxin-producing E. coli (STEC), is also alternatively referred to as verocytotoxin-producing E. coli (VTEC), and enterohemorrhagic E. coli (EHEC). All members of this group are defined by the presence of Shiga toxin 1 (Stx1) or 2 (Stx2). Some but not all EHEC strains are LEE positive and form … Read moreShiga toxin-producing Escherichia coli (STEC)
Enterotoxigenic E. coli (ETEC) Enterotoxigenic E. coli (ETEC) is defined as containing the E. coli strains that elaborate at least one member of two defined groups of enterotoxins: heat-stable toxin (ST) and heat-stable toxin (LT). Enterotoxigenic Escherichia coli, or ETEC, is thus the name given to a group of E. coli that produces special toxins that stimulate the lining … Read moreEnterotoxigenic E. coli (ETEC)
Shigella dysenteriae- Pathogenicity and Clinical Manifestation Shigella dysenteriae is a species of gram-negative, facultatively anaerobic, rod-shaped bacteria that is extremely pathogenic and causes severe dysentery. Infection with this organism often leads to ulceration of the intestinal epithelium. It is known to produce an exotoxin (Shiga toxin) which disrupts protein synthesis and produces endothelial damage. Figure: … Read moreShigella dysenteriae- Pathogenicity and Clinical Manifestation
Neisseria gonorrhoeae is an obligate human pathogen and is the etiological agent of gonorrhea. In the United States, it is the second most commonly reported communicable disease, with more than 350,000 cases reported annually. Syndromes include cervicitis in women and urethritis, pharyngitis and proctitis in both sexes. If untreated, women may experience severe sequelae of … Read moreNeisseria gonorrhoeae- Laboratory Diagnosis, Treatment, Prevention
Klebsiella pneumoniae- Pathogenicity and Clinical Manifestations Klebsiella pneumoniae is a gram-negative, encapsulated, non-motile bacterium that is found in the environment and has been associated with pneumonia in the alcoholic and diabetic patient population. K. pneumoniae is also a well-known cause of community-acquired pneumonia. The bacterium typically colonizes human mucosal surfaces of the oropharynx and gastrointestinal … Read moreKlebsiella pneumoniae- Pathogenicity and Clinical Manifestations
E. coli is the most common and important member of the genus Escherichia. It is a Gram-negative, facultative anaerobic, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Human Escherichia coli strains are classified as commensal microbiota E. coli, enterovirulent E. coli, and extraintestinal pathogenic E. coli on the basis of their genetic features … Read moreE. coli- Pathogenicity and Clinical Manifestations
Laboratory Diagnosis of Clostridium perfringens For Diarrheal Disease Laboratories diagnose C. perfringens food poisoning by detecting a type of bacterial toxin in feces or by tests to determine the number of bacteria in the feces. A count of at least 106 C. perfringens spores per gram of stool within 48 hours of when the illness … Read moreClostridium perfringens- Laboratory Diagnosis, Treatment, Prevention
Acinetobacter baumannii- Pathogenicity and Clinical Features Acinetobacters are strictly aerobic, oxidase-negative, plump gram-negative coccobacilli which are ubiquitous saprophytes, recovered in nature and in the hospitals. They are opportunistic pathogens that cause infections in the respiratory tract, urinary tract, and wounds; they also cause septicemia. Acinetobacter is subdivided into two groups: glucose oxidizing species ( A. … Read moreAcinetobacter baumannii- Pathogenicity and Clinical Features
Laboratory Diagnosis of Klebsiella pneumoniae In the setting of pneumonia, infection with K. pneumoniae is confirmed by either sputum culture analysis, blood culture analysis or midstream urine depending upon the illness. The presence of gram-negative rods in Gram-stained smears suggests Klebsiella; they maybe capsulated and non-sporing. Material is inoculated into blood agar and Mac Conkey agar … Read moreKlebsiella pneumoniae- Lab Diagnosis, Treatment, Prevention
Staphylococcus aureus are catalase-positive, gram-positive cocci which frequently colonize the skin and mucosa of humans and animals. However, it is a highly successful opportunistic pathogen and thus involved in various diseases including toxin-mediated diseases (food poisoning, toxic shock syndrome, scalded skin syndrome), pyogenic diseases (impetigo, folliculitis, furuncles, carbuncles, wound infections), and other systemic diseases. The … Read moreStaphylococcus aureus- Lab Diagnosis, Treatment, Prevention