10L-Neglected Bacteria PDF

Vibrio cholerae, Helicobacter pylori, Mycoplasma pneumoniae, Treponema pallidum Dr. Mohamed Elmutasim Microbiology Department 26 Sep. 2022  Objectives -To Understand the Diseases, pathogenesis, diagnosis and management causes by: Vibrio cholerae, Helicob...

Vibrio cholerae, Helicobacter pylori, Mycoplasma pneumoniae, Treponema pallidum Dr. Mohamed Elmutasim Microbiology Department 26 Sep. 2022  Objectives -To Understand the Diseases, pathogenesis, diagnosis and management causes by: Vibrio cholerae, Helicobacter pylori, Mycoplasma pneumoniae, Treponema pallidum  Vibrio cholerae Diseases: -Watery diarrhea (Rice-water stool) in large volumes. Marked dehydration. Characteristics: -Comma-shaped gram-negative rods. Habitat and Transmission: -Habitat is the human colon. -Transmission is by fecal-oral route. Pathogenesis: Cholera toxin: Subunit A: ADP-ribosylating activity Subunit B: binds toxin to cell surface receptors. The infectious dose is high (>107 organisms).  Helicobacter pylori Diseases: -Gastritis & peptic ulcer. -Risk factor for gastric carcinoma. Characteristics: -Curved gram-negative rod. Habitat and Transmission: -Habitat is the human stomach. -Transmission is by ingestion. Pathogenesis: Organisms synthesize urease, which produces ammonia and damages gastric mucosa. Ammonia neutralizes stomach acid pH, allowing the organism to live in gastric mucosa.  Mycoplasma pneumoniae Diseases: -"Atypical" pneumonia. Characteristics: -Smallest free-living organisms. -Not seen on Gram-stained smear because they have no cell wall, so dyes are not retained. Habitat and Transmission: -Habitat is the human respiratory tract. Transmission is via respiratory droplets. Pathogenesis: Oral Mycoplasma Mycoplasmas have been isolated from saliva, oral mucosa and dental plaque, but their significance is unclear. The oral species include Mycoplasma buccale, Mycoplasma orale and Mycoplasma salivarium. The later two species have been isolated from salivary glands and are thought to play a role in salivary gland hypofunction.  Spirochetes: Treponema pallidum Diseases: -Syphilis Characteristics: -Spirochetes. It is not seen on a Gram-stained smear because the organism is too thin. Not cultured in vitro. Habitat and Transmission: -Habitat is the human genital tract. -Transmission is by sexual contact -from mother to fetus across the placenta Pathogenesis: The organism multiplies at the site of inoculation and then spreads widely via the bloodstream. -Many features of syphilis are attributed to blood vessel involvement causing vasculitis. Primary (chancre) and secondary lesions heal spontaneously. Tertiary lesions consist of gummas (granulomas) in bone, muscle, and skin, aortitis, or central nervous system inflammation. Thank You