Medical bacteriology N. Gonorrhoeae. Introduction

Medical bacteriology N. Gonorrhoeae

1. VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN, VEERACHIPALAYAM, SANGAGIRI, SALAM. DEPARTMENT OF MICROBIOLOGY SUBJECT : MEDICAL BACTERIOLOGY TOPIC : N. GONORRHOEAE SUBJECT INCHARGE SUBMITTED BY Dr. R. MYTHILI, G. LOGAVANI, HEAD OF THE DEPARTMENT, III- BSc. MICROBIOLOGY, DEPARTMENT OF MICROBIOLOGY, VIVEKANANDHA ARTS AND VIVEKANANDHA ARTSAND SCIENCE COLLEGE SCIENCE COLLEGE FOR WOMEN FOR WOMEN, VEERACHIPALAYAM, VEERACHIPALAYAM SANGAGIRI , SANGAGIRI, SALAM. SALAM.TAMILNADU.

2. Introduction N. Gonorrhoeae causes the venereal disease gonorrhea the gonococcus was first described in gonorrheal pus by Neisser in 1879. Bumm in 1885 cultured the coc- cus and proved its pathogenicity by inoculat in human volunteers. Morphology In smears from the urethral discharge in acute gonorhea, the organism appears as a diplococcus with the adjacent sides concave, being thpicelly kindney- shaped.

3. Gram negative diplococci. S ize is 0.6 to 0.8micro meter. Occur in pair Non motile Capsulated and have pili Cultural characteristics Genococci are more difficult to grow then meningococci. They are aerobic but may grow anaerobically also. Growth occurs best at pH 7.2 to 7.6 Temperature of 35-36c. It is essential to provide 5-10 co2. They grow well on choclet agar, mueller - Hinton agar, Thaer martin medium is selective and contains vancomycin , colistin and nystal in, which inhibits most contaminants including non- pathogenic neisseria .

4. Colonies are small, round, translucent, convex or slightly umbonate , with a finely granular surface and lobate margins, they are soft and easily emulsifiable . Four types of colonies have been recognised T1 to T4. Type 1 and 2 small brown colonies. The cocci are piliated , autoagglutinable and virulent. Types 3 and 4 form larger, granular, non pigmented colonies. T3 and T4 cocci are non – piliated . From smooth sus – pensions and are a virulent. Fresh isolates from acutecases of gonorrheag enerally from T1 and T2 colonies. On serial subculture, they change to T3 or T4 colonila morphology. T1 and T2 types are also known as p+ and p++, respectively, while T3 and T4 are kown as p-. Biochemical reaction The virulence factors are, Pili: most important virulence factors. Piliated gonococci are usually virulent, whereas non pilliated strains are a virulent.

5. 2) Two virulence factors in the cell wall. a) Lipooligo saccharide (Los) ( a modified from of endotoxin ). Endotoxin of gonococci is weaker then that of meningococci. B) outer membrane protein ( OMP) OMP cause attachment of bacteria to epithelial cells of the urethra, rectum, cervix, pharynx, or conjunctive like pilli . (3) IgA protease : The main host detenges against gonococci are antibodies (IgA and IgG) complement, and neutrophils. IgA protease degrades one of these antibodies. Other biochemical properties are: They ferment glucose They are oxidase positive. Resistance The gonococcus is a very delicate organism. Readily killed by heat, drying and antiseptics.

6. It is a strict parasite and dles in 1-2 hours inexudates out side the body inculrues , the coccus dies in 3-4 days but survives inslanl cultures at 35 c if kept under sterile Paraffinoil cultures may be preserved foryarsit frozen quickly and stored at -70c. Gonococci contain several plasmids, about 95 present of the strains have a small cryptic plasmid of unknown function. Two other trsnsmissible plasmids contain benes that code beta lactamse which causes resistance to penicillin. Pathogenicity Gonorrhea is a venereal disease that has been known since ancient times. The name gonorrhea was first employed by galen in 130 AD. In the acute stage, diagnosis can be established readily butchronic cases some times present great difficulties.

7. Spread The disease is acquired by sexual contact the first step in infection is adhesion of gonococci to the urethra or other mucosal surfaces pili are involved in thid adhesion. Adhesion is rapid and firm so that micturition after exposure offers no protection against infection. The cocci penerate through the intercellular spaces and reach the subepithelial connective tissue by the third day of infection. The incubation period is 2-8 days. In men the disease starts as acute urethritis with a mucopurulent discharge the infection gonococci in large numbers. The infection extends along the urethra to prostate, seminal vesicles and epidiymis . Chronic urethra to may lead to structure formation. The infection may spread to the periurethral tissue causing abscesses and multiple discharging sinuses ( watercan perineum)

8. In women the initial infection involves the urethra and cervix uteri. The vaginal mucosa is not usually affected in adults because the stratified squamous epithelium is resistant to infection by the cocci and also because of the acid pH of vaginal secretions. The infection may extend to Bartholins glands, the endometrium and the fallopain tubes. Pelvic inflammatory disease and salpingitis may lead to sterilityRarely , peritonitis may develop with perihepatic inflammation ( Fitz- Hugh- Curtis Syndrome). Clinical disease is as a rule less severe in women, many of whom may carry gonococci in the cervix without any symptoms. Asymptomatic csrriage of gonococci is rare in men. Disseminated gonococcal infection ( DGI) is a severe from of systemic illness.

9. Proctitis occurs in both sexes. It may develop by direct contiguous spred in women but in men is usually the result of anal sex. Conjunctivitis may occur, usually due to autoinoculation by the patients fingers. Blood invasion may occur from the primary site of infection and may lead to metastatic lesions such as arthritis, ulcerative endocarditis and very rarely meningitis. Occasial cases of pyemia have been reported. Opthalmia neonatorum , a non venereal infections is gonococcal ophthalmia in the newborn , which results from direct infection during passage through the birth canal. Gonococcal bacteremia leads to skin lesions, especially hemorrhagic papules and pustules on the hands, forearn , feet and large, and to tenosynovitis and suppurative arthritis, usually of the knees,ankles and wrists. Epidemiology Gonorrhea is an exclusively human disease, there being no natural infection in animals.

10. Laboratory diagnosis It is a frequently isolated from sample such as blood, CSF. Different methods for laboratory diagnosis are: Gram staining Culture Oxidase test Fermentation test Latex agglutination test Gram staining The diagnosis is suggested by the finding gram negative bacteria bean shaped capsular diplococci.

11. Culture The organism is cultured on blood agar chocolate agar incubated at 37 c in a 5% co2 atmosphere. Colonies are 1-2 mm in diameter, convex, grey and transparent. No hemolysis .

12. Oxidase test Test on first paper or directly on plate Oxidase reagent = Dimethyl or tetramethyl oxidase reagent Violet- purple color indicates a positive result.

13. Manitol fermentation : N. Gonorrhoea ferment manitol . Maltose fermentation : N. Gonorrhoea do not ferment maltose Treatment Penicill PPNG( penicillinase - producing N. Gonorrhoea have spread widly . Ceftriaxone- 125 mg Ciprofloxacin-500 mg Ofloxacin-400 mg Ceftriaxone- 125 mg Prophylaxis Control of gonorrhea consist of early detection of cases, contact tracing health education and other general measures.

14. As even clinical disease does not confer any immunity , vaccination has no place in prophylaxis.

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