Lecture 9 Neisseria Gonorrhoeae (Gonnorhea)

Urogenital System Microbiology… Lecture 9 Neisseria gonorrhoeae (Gonnorhea) 1 _first: General features: I. II. III. Gram negative diplococcic, Oxidase Positive with opposing sides flattened (Kidney/coffee Bean appearance) The Outer membrane has: - Phospholipids, Lipopolysaccharides (LPS), Lipooligosaccharides (LOS) - OMPs (Porins: Por1BA, Por1BB) - 12 Opa antigens (opaque) for adherence (called Opa because they give opaque colony appearance) Intracellular organisms without capsule _second: Epidemiology: I. II. III. IV. Acquired by sexual contact (chance 20%-50%), and rarely with Nonsexual transmission, e.g., via toilet One of greatest public health problems, mainly in adolescents (sexually active) 50% of infected women are asymptomatic (Difficulty in detecting cases) Resistance to many antibiotics _third: Pathogenesis: I. Attachment: - Pili and Opa mediate attachment to non- ciliated epithelium via these receptors (CD46, CD66, and integrins) - OMPs (Por1BA) trigger enzymatic activity, phagocytosis and cell invasion - Bacteria quickly pass to submucosa from infected cells…BUT, they haven’t capsule which makes their transmission to the blood rare II. Antigenic variations - Pilin genes expressed (pilE) or silent (pilS) Opa: On and off genes, sometimes appear sometimes don’t LOS: Genetic mechanism is unknown, but there are many types of them Variation is a Way to escape from immune surveillance, how? When an antibody binds to an antigen, variation allows the predominance of new antigenic variants 2 III. Survival in the Submucosa - Scavenge iron, - Not capsulated, but has LOS (can bind to sialic acid) so, they bind to factor H of complement system and blocking C3b…as a result, block phagocytosis - Phagocytized gonococci resist killing (live inside immune cells) IV. Spread and Dissemination: V. - Local spread to epididymis & fallopian tubes - LOS & peptidoglycan shedding cause injury to local tissues. - Rarely reach bloodstream (then called, Disseminated Gonococcal Infection “DGI”) immunity: - Antibody response is weak (Antigenic variations) _fourth: Clinical manifestations: I. In men: - II. Primary site: Urethra Start: 2 – 7 days after infection Purulent urethral discharge and dysuria Epididymitis or Prostatitis but Uncommon In women: - Primary site: Endocervix - Vaginal discharge, urinary frequency, dysuria, abdominal pain, menstrual changes - Mild symptoms are Common, but could be asymptomatic III. Rectal gonorrhea - Symptomless, tenesmus (need to pass stool in spite of empty colon), discharge & bleedings IV. Pharyngeal gonorrhea: - Symptomless, sore throat, cervical adenitis, lymphadenopathy V. Ophthalmia Neonatorum - Severe, acute, purulent conjunctivitis - Acquired during childbirth from infected mother vagina 3 VI. Pelvic Inflammatory Disease (PID) - Develops in 10% to 20% women with gonorrhea Fever, abdominal pain (bilateral), tenderness and leukocytosis Salpingitis (inflammation of fallopian tube), pelvic peritonitis, and abscesses Occurs together with C. trachomatis and anaerobes Leads to infertility and ectopic pregnancy, due to Blocking and damaging in the fallopian tube _fifth: Diagnosis: I. Gram Smear: - Bean-shaped, gram negative diplococcic within neutrophils - More than 95% of specimen are sensitive and specific in men, in women sensitivity is 50%-70% - Diagnosis by Gram smear is taken in men, but not taken solely in women II. Culture: - Grow well on Chocolate agar, requires CO2 (they are fastidious): Small, smooth, nonpigmented colonies - Samples: • From men: Urethral exudate or scraping Chocolate Agar/ Colonies Smooth, Convex, Translucent, 1 mm diameter 4 III. • From women: Cervical swab is better than Vaginal or urethral specimens. Better yield with anal canal culture - Culture promptly (Should be cultured immediately, bed-side), with 5%-10% CO2/ fastidious - Medium: Thayer-Martin (5% sRBC/Chocolate + Antibiotics), we add antibiotic to kill any other microorganisms which may be contaminated, of course gonorrhoeae will be resistant to these antibiotics Biochemical and serological to speciate (to know the species) - Direct Detection • Immunoassay, Nucleic Acid Amplification (NAA) for genital and urine specimens (diagnostic) - Confirm by culture. – NAA done also with Chlamydia • For screening - Serology: Neither Sensitive nor Specific tests _sixth: Treatment and Prevention I. II. III. IV. Penicillin: Increasing MIC dose to 8.0 µg/mL *MIC is the lowest concentration (in μg/mL) of an antibiotic that inhibits the growth of a given strain of bacteria. *Increased MIC means they are resistance to , so not used Third generation cephalosporins: - Ceftriaxone IM injection - Oral doses not preferred Treat for Chlamydia: Azithromycin or doxycycline (oral) Prevention: Condoms block transmission, No vaccine 5