Online microbiology notes by SAGAR ARYAL
Enteroinvasive E. coli (EIEC) Enteroinvasive E. coli (EIEC) strains are rare in both developed and developing countries. EIEC infections are characterized by a period of watery diarrhea that precedes the onset of scanty dysenteric stools containing blood and mucus. Pathogenic strains are primarily associated with a few restricted O serotypes: O124, O143, and O164. EIEC … Read moreEnteroinvasive E. coli (EIEC)
Morphology of Bacteria Morphologically bacteria can resemble: Cocci (Singular: coccus) Bacilli (rods) (Singular: rod, bacillus) Vibrios (Singular: vibrio) Spirilla (Singular: spirillum) Spirochaetes (Singular: spirochaete) Cocci These are round or oval bacteria measuring about 0.5–1.0 um in diameter. When multiplying, cocci may form pairs, chains, or irregular groups: cocci in pairs are called diplococci, e.g. meningococci … Read moreMorphology of Bacteria
Differences between Pneumococcus and Viridans streptococci Streptococcus pneumoniae can be differentiated from Viridans streptococci by various features: S.N. Properties Pneumococcus Viridans streptococci 1 Morphology Lanceolate or flame-shaped Round/oval 2 Arrangement Gram-positive cocci in pairs Gram-positive cocci in long chains 3 Capsule Present Absent 4 On blood agar Draughtsman or carom coin colony Convex shaped colony … Read moreDifferences between Pneumococcus and Viridans streptococci
Answer: Thiosulfate-citrate-bile salts-sucrose (TCBS) Agar is used for the selective isolation of Vibrio cholerae and other enteropathogenic vibrios. TCBS agar is composed of yeast extract, peptone, sodium thiosulfate, sodium citrate, ox bile (oxgall), sucrose, sodium chloride, iron (III) citrate, bromothymol blue, thymol blue, agar, and distilled or deionized water. TCBS is not autoclaved because: This … Read moreWhy TCBS agar is not autoclaved?
Answer: It is a non-selective, non-differential medium. This means that almost all organisms plated on here will grow. It contains starch. Starch is known to absorb toxins released from bacteria so that they cannot interfere with the antibiotics. It also mediates the rate of diffusion of the antibiotics through the agar. It is a loose … Read moreWhy MHA is used for antibiotic susceptibility testing?
Factors affecting bacterial pathogenicity A microbe that is capable of causing disease is referred to as a pathogen. Pathogenicity is the ability of a microorganism to cause disease in another organism, namely the host. Pathogens vary in their ability to produce disease. The measurement of pathogenicity is called virulence, with highly virulent pathogens being more likely to cause disease … Read moreFactors affecting bacterial pathogenicity
Enteroaggregative E. coli (EAEC) Enteroaggregative E. coli (EAEC) are a heterogeneous collection of strains characterized by their autoagglutination in a “stacked-brick” arrangement over the epithelium of the small intestine and, in some cases, the colon. EAEC strains are currently defined as E. coli strains that do not secrete enterotoxins LT or ST and that adhere to HEp-2 … Read moreEnteroaggregative E. coli (EAEC)
Enteropathogenic Escherichia coli (EPEC) Two groups of E. coli are responsible for enteric disease: Enteropathogenic E. coli [EPEC] and some Shiga toxin–producing E. coli [STEC]. They both possess a cluster of virulence genes located on a chromosomal pathogenicity island called the locus of enterocyte effacement (LEE). The EPEC are however, defined by: Presence of LEE and Absence … Read moreEnteropathogenic Escherichia coli (EPEC)
E. coli Pathotypes- ETEC, EPEC, EHEC, EAEC, EIEC, DAEC Escherichia coli (commonly abbreviated E. coli) 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 (ExPEC) on the basis of their genetic features … Read moreE. coli Pathotypes- ETEC, EPEC, EHEC, EAEC, EIEC, DAEC
Urinary Tract Infection (UTI)- Types, Causative Agents, Pathogenesis, Symptoms, Complications, Risk Factors, Diagnosis, Treatment and Prevention A urinary tract infection (UTI) is an infection that affects part of the urinary tract. The urinary system is made up of the kidneys, ureters, the urinary bladder, and the urethra. Most UTIs are restricted to infection of the bladder (cystitis), though infection may occur in any area of … Read moreUrinary Tract Infection (UTI)