LABORATORY DIAGNOSTICS OF MENINGOCOCCAL AND GONOCOCCAL INFECTIONS

Actuality. Gonorrhea (also called the clap and the drip) caused by Neisseria gonorrhoeae is an important public health problem and the most common reportable infectious disease. Gonorrhea is most frequently spread during sexual contact. However, it can also be transmitted from the mother's genital tract to the newborn during birth, causing ophthalmia neonatorum and systemic neonatal infection.

Meningococcal (Neisseria meningitidis) bloodstream infections (known as meningococcemia) can range in severity from a transient bacteremia that is relatively benign to an overwhelming infection that is rapidly fatal. Meningitis commonly occurs during the course of meningococcemia. In rare cases, N. meningitidis organisms can spread hematogenously to other sites, such as the pericardium, the joints, and the eyes.

Primary objectives: to be able to conduct and evaluate the microbiological diagnosis of meningococcal and gonococcal infections.

QUESTIONS FOR DISCASSION

1. Biological properties of Neisseria spp.

2. Gonococcal infections (Gonorrhea, conjunctivitis of the newborn, pelvic inflammatory disease (PID); microbiological diagnostics. Principles of Borde-Gangu test (CFT) for diagnostics of Gonorrhea.

3. Epidemiology and pathogenesis of the diseases caused by gonococci. Specific features of immunity in such cases.

4. Principles of Gonococcal infections; prophylaxis and treatment (features of treatment of chronic gonorrhea).

5. Principles of microbiological diagnostics of meningitis.

6. Epidemiology and pathogenesis of the diseases caused by meningocci. Specific features of immunity in such cases.

PROCEDURE OF PRACTICAL SESSION

Task 1. Microscopically examine the preparation (Gram stained) isolated from the urethra of women suspected of gonorrhea. Draw a conclusion in relation to the results of microscopic research. Complete the protocol.

Task 2. Microscopically examine the preparation (Gram stained) from the spinal fluid of a child suspected of meningitis. Draw a conclusion in relation to the results of microscopic research. Complete the protocol.

Task 3. Examine the growth of Neisseria meningitides on blood agar. Write the description of cultural properties in the protocol.

Task 4. Attentively study CFT with a gonococcal antigen. Enter the result of reaction in the minutes, explaining the mechanism of its formation.

Task 5. Examine the sensitivity of N. gonorrhoeae to antibiotics, make the conclusion. Write down the results of the experiment in the protocol.

Task 6. Study main antimicrobial drugs used for treat­ment, prevention and diagnostics of meningococcal and gonococcal diseases, write them down in the copy book.

RECOMMENDATIONS FOR PRACTICAL WORK

Task 1.

There are gram-negative diplococci and leucocytes in it (incomplete phagocytosis) in the smear from urethra of women that suspected of gonorrhea. Such microscopic picture is characteristic at sharp gonorrhea. At the chronic form of gonorrhea gonococci can not come to light microscopically.

Task 2.

In spinal fluid of a child suspected of meningitis, you will observe the presence of intra- and extracellular gram-negative diplococci (meningococci).

Finding out the causative agents in the spinal fluid (by microscopy or bacteriological methods) is absolute proof of the proper infectious disease of CNS.

Task 3.

Meningococci are strict aerobes, very demanding to the nutrient media and terms of cultivation. Therefore, grow only media with addition of albumens natively (serum, blood and other). In this case, meningococci are cultivated on the blood agar at the temperature of 37°C. On a blood agar, meningococci form the shallow, tender colonies of oily consistency.

Task 4.

CFT is more frequent used for the serodiagnosis of chronic gonorrhea. CFT conduct on Borde-Gangu on a standard chart. The reaction is positive with 3 - 4 weeks of illness.

Task 5.

Certainly, specific preparation for treatment of gonorrhoea gets out depending on the form of this infection.

Task 6.

Vaccine gonococcal inactivated liquid (Gonovaccine) is a suspension for intramuscular introduction, represents a suspension inactivated cultures of N.gonorrhoeae in 0,9 % solution of sodium chloride. General biological properties of this vaccine - increase of specific reactance of an organism. It is using for immunotherapy (auxiliary method of treatment of gonorrheal infection from 3-years-old age) the chronic form of gonorrhea; and for provocation of chronic gonorrhea. This vaccine can be used for diagnostics (to establish whether a patient was cured completely from gonorrhea).

Meningococcal chemical vaccine contains cleared polysaccharide of Neisseria meningitidis of group A and C. It is using for prophylaxis of cerebrospinal meningitis caused by meningococcus of serogroup A and C. Vaccination is recommended in endemic regions, and also in case of epidemic caused by meningococcus of serogorup A or C.

Gonococcal antigen is inactivated N. gonorrhoeae. Preparation is used for serological diagnostics of gonorrhoea in CFT.

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Date: 2016-01-14; view: 1047