Neisseria Gonorrhoeae: Characteristics, Pathogenesis, and Clinical Findings

Neisseriae Characters :- Gram-negative diplococci, individual cocci are kidney-shaped, non motile non hemolytic and non pigmented, Colonies are opaque or transparent. There are two pathogenic species for humans : 1. Neisseria gonorrhoeae neonatal conjunctivitis (ophthalmia neonatorum) and pelvic inflammatory disease (PID). Neisseria gonorrhoeae (Gonococci) GC (Gonococci) GC, the causative agent of gonorrhea, 2. Neisseria and meningococcemia. Neisseria meningitidis meningitidis (Meningococci) MC (Meningococci) MC, the causative agent of meningitis

all N. Spp. Are oxidase-positive (ie. Produce oxidase enzyme ). The oxidase is a key test for identifying them. When bacteria are spotted on a filter paper soaked with tetramethylpara phenylenediamine (oxidase reagent), The Neisseriae rapidly run dark purple. The growth of both organisms(GC and MC) is inhibited by toxic trace metals and fatty acids found in certain culture media e. g., blood agar plate, they are therefore culture on chocolat agar containing blood heated to 80 c. The organisms are rapidly killed by drying, sunlight, moist heat and many disinfectants. (they are fastidious). Non Branhamella catarrhalis (Neisseria catarrhalis). Non pathogenic pathogenic e. g. Moraxella catarrhalis was previously named

Neisseria gonorrhoeae (Gonococci) GC. Neisseria gonorrhoeae (Gonococci) GC. Classification Classification : :- - On the basis of morphology and their colonial mutation, there are four biotypes : (T1, T2) virulent small brown colonies (pilitated gonococci) posses pili which are adherence factors. (T3, T4) a virulent large non pigmented colonies (no pilitated gonococci). Virulence factors (antigenic structure) : Virulence factors (antigenic structure) :- - 1. pili acts as adhesions. 2. porprotien. 3. opaproteins. 4. Rmp(protein111). 5. Iipopolysaccharide(in gonococei is called a lipooligosaccharide, LOS, as endotoxin). 6. IGA1 protease.

Pathogenesis : Gonococci cause--gonorrhea (sexually transmitted disease STD or veneral disease) -Ophthalemia neonatorum. Pathogenesis :- - Gonorrhea (example urithritis, cervicitis) Gonorrhea is usually symptomatic in men but often asymptomatic in women. Gonococci are sexually transmitted. The transmission of these bacteria is through direct contact of mucous membrane -to mucous membrane, usually sexually contact ; mother-to-neonate during birth. GC attack mucous membrane of genitourinary tract, eye, rectum and-throat.

Clinical finding : Clinical finding :- - Gonococci caused infections with seeding of organs, GC reach these organs via the bloodstream(gonococcal bacteremia), Gonococci caused both localized infection in the genital tract and disseminated gonorrhea -ln men is characterized primarily by urethritis accompanied by dysuria (painful urination) and purulent discharge complication include (Epididymitis and prostatis). gonorrhea -In women cervicitis and the most frequent complication is an ascending infection of the uterine tubes (salpingitis, PID) which can be result in sterility and ectopic pregnancy as a result of scarring of the tubes. Disseminated gonococci infections (DGI) In newborn infant GC. Can cause ophthalemia neonatorum, an infection of the eye of the newborn, is acquired from the mother during passage through an infected birth canal. Disseminated gonococci infections (DGI) arthritis, skin lesion. Other sexually urithritis (NGU) caused by Chlamydia trachomatis, can coexist with gonorrhea therefore appropriate diagnostic and therapeutic measures must be taken. Other sexually transmitted infections, example, syphilis and non gonococcal

Lab. Diagnosis :- 1 1. . Specimens rectum. 2 2. . Gram stained smear PMNs )polymorphoneuclear cells) from urethral discharge in men is sufficient for diagnosis while in women false positive because of the normal flora interference 3 3. . Culture, on A. b. antibiotics (vancomycin, colistin and nystatin to suppress the normal flora found in the specimen. C. The culture is incubated in an atmosphere containing 5% COZ (candle extinction jar) at 37 c. 4 4. . Oxidase test positive 5 5. . Sugar fermentation bases glucose and maltose. 6 6. . Nucleic acid amplification test. 7 7. . Serology by ELISA, antibodies against diagnosis. Specimens, pus, secretion from urethra, cervix, conjunctiva, throat and Gram stained smear, then we look intracellular Gram-negative diplococci in Culture, on A. Chocolate agar. b. Thayer Chocolate agar. Thayer- -Martin agar Martin agar. (selective medium) which is chocolate agar containing C. Modified Thayer Modified Thayer- -Martin agar Martin agar. same as(Thayer-Martin agar plus trimethoprim) Oxidase test positive. Sugar fermentation the differentiation between GC and MC is made on the Nucleic acid amplification test. Serology by ELISA, antibodies against pili pili. These test are not useful for

Treatment Treatment Ceftriaxon plus doxycyclin. Some strain of GC called penicillinase producing gonorrheae or (PPNG) possess plasmids containing the gene for penicillinase production(resistant to penicillin). Control and prevention : Control and prevention :- - Treatment of symptomatic patient with contact, cases on gonorrhea must be reported to the public health department to ensure proper follow up. Gonococci conjunctivitis is preventive by the use of erythromycin ointment. Silver nitrate drops are use less frequently. No vaccine is available.

Neisseria Neisseria meningitides (Meningococci meningitides (Meningococci) ) At least 13 serologic groups on the basis of the antigenicity of their capsular polysaccharide (A, B, C, D, X, Y, Z, W135, 29E, H, I, K, and L). The route of infection is nasopharynx, MC present as normal flora of nasopharynx, these MC stimulate the carrier antibodies( natural immunity ) these carrier are asymptomatic. Two organisms cause more than 80% of cases bacterial meningitis in persons over 2 months of age : Streptococcus pneumonia and Neisseria meningitides of these organism. MC in group A cause epidemics of meningitis. virulence factors :- a. a. polysaccharide capsule which act antiphagocytic factor. D. C. virulence factors (antigenic structures factors (antigenic structures): ):- - Meningococci have three virulence D. Endotoxin (LPS) which cause fever, shock. C. IgA1 protease cleaves secretory IgA.

Pathogenesis and clinical finding : Pathogenesis and clinical finding :- - Disease meningitis and meningococcemia, MC spread via respiratory secretions, MC via nasopharynx-blood stream bacteremia (meningococcemia) intravascular coagulation and spread-meningitis most common complication of meningococcemia-fulminant meningococcemia (septic shock). Meningitis most common disease in children less than 1 year.

Lab. Diagnosis : Lab. Diagnosis :- - 1. 1. Specimens from blood, CSf and nasopharyngeal swap. 2. within polymorphonuclear leukocyte or extracellularly. 2. Direct-Gram stain smear of centrifuged CSF shows MC as typical Neisseria 3. with 5% CO2. Also culturing in Thayer martin agar and modified TM. 3. Culture, CSF specimen are plated on Choclate agar and incubated at 37oC 4 4. . Biochemical test :- --Oxidase test-positive. --Sugar fermentation test, ferment maltose and glucose. 5. latex antibodies give 5. Serology, antibodies to meningococcal polysaccharides can be measure by latex agglutination agglutination test test or by measuring the bactericidal activity. These

Treatment : Treatment :- - Penicillin G is the drug of choice. Prevention and control : Prevention and control :- - Vaccine contains capsular polysaccharide of strains A, C, Y and W-135, rifampin or ciprofloxacin given to clos contact to decrease oropharyngeal carriage. Moraxella bronchitis, pneumonia, otitis media and conjunctivitis, this spp. Produce beta-lactamase so its resistant to peniciliin. It produces butyrate esterase. Moraxella catarrhalis catarrhalis : :- -normal flora of the upper respiratory tract, it causes