Incidence of Haemophilus influenzae type b meningitis in India.

BACKGROUND & OBJECTIVE: Vaccine policy depends on locally relevant disease burden estimates. The incidence of Haemophilus influenzae type b (Hib) disease is not well characterized in the South Asian region, home to 30 per cent of the world's children. There are limited data from prospective population incidence studies of Hib in Asia, and no data available from India. We therefore carried out this study to assess the burden of Hib meningitis in India. METHODS: A prospective surveillance study was carried out during 1997 and 1999 in hospitals for cases of Hib meningitis from 5 administrative areas of an Indian district (Vellore, Tamil Nadu) with 56,153 children under 5 yr of age, over a 24 month period RESULTS: Ninety seven cases of possible meningitis (> 10 WBC/microl in CSF) were reported, an annual incidence of 86 per 100,000 (95%CI 69 to 109) in 0-4 yr old children, and 357 per 100,000 in 0-11 month infants. Eighteen had proven bacterial meningitis, an annual incidence of 15.9 per 100,000. Eight CSF had Hib by culture or antigen testing, an annual incidence of 7.1 per 100,000 (95%CI 3.1 to 14.0) in children 0-59 months. In infants 0-11 months of age, the incidence of Hib meningitis was 32 per 100,000 (95%CI 16 to 67) and in the 0-23 month group it was 19 (95%CI 8 to 37). INTERPRETATION & CONCLUSION: Our data are the first minimal estimate of the incidence of Hib meningitis for Indian children. The observed incidence data are similar to European reports before Hib vaccine use, suggest substantial disease before 24 months of age, and provide data useful for policy regarding Hib immunization.

Age- and cause-specific childhood mortality in Lombok, Indonesia, as a factor for determining the appropriateness of introducing Haemophilus influenzae type b and pneumococcal vaccines.

Using age and cause-specific childhood mortality in Lombok, Indonesia, as a factor for determining the appropriateness of introducing Haemophilus influenzae type b (Hib) and pneumococcal vaccines, the study describes a cross-sectional, hamlet-level mortality survey in 40 of 305 villages in Lombok Island, Indonesia. Causes of death were assessed with a standardized verbal-autopsy questionnaire. One thousand four hundred ninety-nine births and 141 deaths occurring among children aged less than 2 years were identified, with 43% of deaths occurring during the first 2 months of life. The infant mortality rate was 89 (95% CI: 75, 104) per 1,000 live-births. All mortality rates are reported per 1,000 live-births. To examine children whose deaths could potentially have been prevented through vaccination with Hib or pneumococcal vaccine, deaths due to acute respiratory infection (ARI) and central nervous system (CNS) infections among children, aged 2-23 months, were analyzed. ARI and CNS infections caused 58% (mortality rate: 31 per 1,000 live-births; 95% CI: 23, 41) and 17% (mortality rate: 9 per 1,000 live-births; 95% CI: 5, 16), respectively, of all deaths within this age group. Between the ages of 2 and 23 months, 5% of all babies born alive died of ARI, and another 1% died of CNS infections. Our results indicate that current efforts to reduce childhood mortality should focus on reducing ARI and meningitis. These efforts should include evaluating the impact of Hib and pneumococcal vaccines within the routine Expanded Programme on Immunization system.

Changing trend in susceptibility pattern of Streptococcus pneumoniae to penicillin in India.

Prior to 1995 all strains of Streptococcus pneumoniae isolated at a tertiary care hospital in south India were uniformly susceptible to penicillin. However, since late 1995 strains of S. pneumoniae with intermediate resistance to penicillin have been observed. Altogether there were 25 such isolates, 9 from invasive (5 from CSF as well as blood, 1 from pleural fluid and 3 from CSF alone) and 16 from noninvasive sites (6 from throat, 6 from sputum, 3 from eye and 1 from ear) respectively, thus 4.6 per cent of S. pneumoniae showed intermediate resistance of a total of 535 strains studied so far. The minimum inhibitory concentration (MIC) values of penicillin, erythromycin, chloramphenicol and cefotaxime were determined by agar dilution method and for confirmation, E test was carried out for penicillin alone. The MIC range obtained for penicillin was between 0.125-1.0 microgram/ml. Kirby-Bauer disc diffusion method was adopted for testing of erythromycin, chloramphenicol, co-trimoxazole, cefotaxime, tetracycline and vancomycin. We observed that none of the strains with intermediate resistance to penicillin were multidrug resistant. These strains belonged predominantly to serotype 14 (n = 10), 7B (n = 9), 19A (n = 3), 7F (n = 2) and 23F (n = 1). Clonality was not observed in the 5 representative strains subjected to Box A finger printing method.

E test as an alternative to conventional MIC determination for surveillance of drug resistant Streptococcus pneumoniae.

A commercial E test was compared with the standard agar dilution method for the determination of minimum inhibitory concentration (MIC) of penicillin, erythromycin, chloramphenicol and cefotaxime for 36 strains of Streptococcus pneumoniae from patients with invasive diseases. Additional strains were tested for MIC values for penicillin (6), erythromycin (14) and cefotaxime (13) for a better statistical evaluation. Besides, 5 reference standards with predetermined MIC values obtained from WHO pneumococcal reference center at Copenhagen, Denmark were tested for penicillin and erythromycin, for quality assessment using both agar dilution as well as E test methods. An overall agreement within +/- 2 dilutions was noted for 97 per cent of the strains tested for all the antimicrobials. A high degree of correlation was noted for erythromycin (r = 1), penicillin (r = 0.99), chloramphenicol (r = 0.95) and cefotaxime (r = 0.9). In MIC determination of a single antimicrobial for diagnostic purpose, E test was found to be more cost effective than conventional agar dilution method. E test was simple to perform, easy to interpret and a valid method for MIC determination of antimicrobials for S. pneumoniae in our center.

Prevalence of pneumococcal serotypes in invasive diseases in southern India.

Forty two pneumococcal strains obtained in Vellore, Tamil Nadu, from 42 patients with invasive diseases, namely pneumonia, meningitis, or peritonitis were typed. Over one-third of pneumococci in children and nearly half in adults were serotype followed by serogroups/types 5, 6 and 7 which were most common in children and adults taken together. These 4 serogroups/types accounted for 11 (79%) of 14 strains in children and 20 (71%) of 28 strains in adults. The remaining 11 strains belonged to 8 serogroups/types, namely 3, 4, 10, 11, 12, 13, 19 and 20.

C substance--specific latex agglutination for early & rapid detection of Streptococcus pneumoniae in blood cultures.

A slide agglutination test was developed using latex particles coated with antiserum against the C substance, a common antigen for all serotypes of Streptococcus pneumoniae. This test was used for the rapid identification of pneumococci in blood culture broths which contained Gram positive cocci (GPC) in pairs or short chains on smear examination. Of 238 consecutive blood cultures with GPC tested, 72 were positive for Strep. pneumoniae by the latex test and conventional methods. The remaining 166 cultures were negative for both these, indicating a 100 per cent specificity and sensitivity for the test.