N. gonorrhoeae and Moraxella Flashcards
General Features and habitat of N. Gonorrhoea
Gram – (diplococci)
Habitat- genital tract
Biochemical Properties of N. Gonorrhoea
Facultative intracellular in PMNs (e.g. neutrophils, eosinophils etc.)
Oxidase +
IgA protease
Ferment only Glucose (used to distinguish between N. meningitidis)
No capsule (different from N. meningitidis, thus no vaccination)
Fimbriae (pili) and surface proteins (Opa, Por, Rmp)- adherence and penetration
Transferrin-binding protein, lactoferrin-binding protein, hemoglobin-binding protein
Pathogenesis of N. Gonorrhoea
Sexual Transmitted Disease (STD) or transmitted to baby during delivery
Lipooligosaccharides (LOS) endotoxin of cell wall causes inflammation
Clinical Features of N. Gonorrhoea
Thick purulent exudation- “bonjour drop” in both sexes (unlike Chlamydiae- watery)
Males: adhere to urethral epithelium due to pili causing acute urethritis
Can ascend further, causing prostatitis, orchitis and even proctitis
Females: ascends the urethra causing Pelvic Inflammatory Disease (PID) This include- gonorrheal urethritis, cervicitis and vaginitis (in teens)
Can lead to scarring- eventually to infertility or ectopic pregnancy o
PID can spread to peritoneum known as Fitz Hugh Curtis syndrome
Infection of peritoneum can lead to adhesions to the capsule of liver. These long and thin adhesions referred to as “violin string adhesions”
Pregnant women affected can transmit it to their baby during delivery. This will cause very fast onset of purulent conjunctivitis in newborns (ophtalmoblenorrhoea neonatorum) within the first 5 days of life. In severe cases can result in blindness
Purulent polyarthritis- common in the knee, asymmetrically
In disseminated cases- fever, rash, meningitis and sepsis can occur (both sexes)
Diagnosis of N. Gonorrhoea
Fastidious- grow on Chocolate agar with 5-10% CO2
Thayer Martin medium- A.K.A VPN agar (Vancomycin Polymyxin Nystatin)
Light microscope- sample from purulent exudate and detection by direct Gram or
methylene blue dye (faster staining technique)
Treatment of N. Gonorrhoea
Ceftriaxone (use if co-infection with Chlamydia, can also add together Macrolide) 1% Ag-acetate (formerly Credé eye drops- AgNO3)- for neonatal conjunctivitis
Moraxella general info
Moraxella, named after the Swiss ophthalmologist Morax, who first recognized the species; part of Moraxellaceae family.
All are Gram negative, diplococci, oxidase positive, seen as white colonies when cultured.
Species are part of the normal flora of the skin, supper respiratory tract and genitourinary tract.
Morphology and habitat of Moraxella catarrhalis
Morphology: Gram negative, diplococci
Habitat: part of normal upper respiratory tract flora
Biochemical features of Moraxella catarrhalis
Obligate aerobic
Oxidase positive
Diseases of Moraxella catarrhalis
Bronchopneumonia
Bronchitis
Sinusitis
otitis media (the two are most commonly in previous healthy people)
Virulence factor of Moraxella catarrhalis
unknown
pathogenesis of Moraxella catarrhalis
mostly affects children; patients with compromised pulmonary system (e.g. COPD)
Treatment of Moraxella catarrhalis
Cephalosporin
Amoxicillin with Clavulanic acid (beta-lactam with enzyme inhibitor)
Diseases of Moraxella lacunata
Subacute conjunctivitis
Treatment of Moraxella lacunata
Cephalosporin
Amoxicillin with Clavulanic acid (beta-lactam with enzyme inhibitor)
