Module 8 - LESSON 2

• Campylobacter is a faintly staining gram-negative bacilli, small, curved or seagull-winged, with darting motility.
• Pontiac Fever is a self-limited, non-fatal respiratory infection.
• Other infections caused by Legionella include wound abscess, Encephalitis, and Endocarditis.
• Legionnaire’s Disease is a severe form of pneumonia also known as “Legionella”.
• Most species of Campylobacter require selective media, such as Campylobacter blood agar (Becton-Dickinson), which contains a blood agar base with the antibiotics vancomycin, polymyxin, cephalothin, trimethoprim, and amphotericin B added.
• The catalase test demonstrates the presence of catalase, an enzyme that catalyses the release of oxygen from hydrogen peroxide (H2O2).
• The nitrate test is used to determine the ability of an organism to reduce nitrate (NO3) to nitrite (NO2) using the enzyme nitrate reductase.
• Most species of Campylobacter, including C. jejuni subsp. jejuni, C. coli, and C. fetus subsp. fetus, are positive in the nitrate test.
• The urease test identifies those organisms that are capable of hydrolyzing urea to produce ammonia and carbon dioxide.
• Campylobacter species are negative to the urease test.
• Hippurate hydrolysis is used in the presumptive identification of Gardnerella vaginalis, Campylobacter jejuni, Listeria monocytogenes, and group B streptococci, by detecting the ability of the organism to hydrolyze hippurate.
• C. jejuni subsp. jejuni is the only positive among Campylobacter species in hippurate hydrolysis.
• Helicobacter, previously known as Campylobacter pylori, is a gram-negative, helically shaped, microaerophilic bacterium, small, translucent, circular colonies, and affects the human stomach.
• For cultivation, Helicobacter is plated in selective media (CAMPY-CVA).
• H. fennelliae is associated with septic shock in non-HIV infected heterosexual immunocompromised patients.
• Legionella is identified by inoculating it in two agar plates: BCYE with charcoal, cysteine, yeast extract, a-ketoglutarase, and iron, and BCYE base with polymyxin B, anisomycin, and cefamandole, and incubating it at 35 to 37°C.
• Legionella causes a disease with a 10-20% fatality rate.
• Pylori is recovered from tissue biopsy such as gastric antral biopsies, chocolate agar, Brucella agar with 5% sheep blood (Non-selective media).
• Legionella is considered to be biochemically inert and is identified using a monoclonal immunofluorescent stain, which is an emulsion of the organism in 10% neutral formalin, diluted 1:100 and placed on slides for fluorescent antibody staining.
• Selective agars in Skirrow’s and Modified Thayer Martin’s agar are used for cultivation of Pylori.
• Pylori is associated with diseases such as peptic ulcer disease, gastritis, and gastric cancer.
• Pylori is associated with diseases such as proctitis, enteritis, and sepsis in homosexual men, and septicemia, cellulitis, meningitis in immuncompromised individuals.
• Numerous EIAs for detection of IgA and IgG, positive results for oxidase, catalase, and rapid urease tests are used for serologic diagnosis of Pylori.
• Legionella is a gram-negative bacilli which are faintly staining, thin, and motile, and requires medium containing Iron and L-Cysteine, buffered to pH 6.9 for optimum growth.
• Cultivation up to 1 week in a moistened, microaerobic atmosphere at 35° to 37°C may be necessary before growth of human pathogen is observable.