Comparison of PCR, culture & serological tests for the diagnosis of Mycoplasma pneumoniae in community-acquired lower respiratory tract infections in children.

BACKGROUND & OBJECTIVE: Mycoplasma pneumoniae is known to be a major cause of lower respiratory tract infections in children. A specific diagnosis is important to institute the appropriate treatment. Information on diagnostic methods used for M. pneumoniae in Indian paediatric population is scarce. The study was thus conducted to compare polymerase chain reaction (PCR), culture and serology for the diagnosis of M. pneumoniae in community-acquired lower respiratory tract infections in children. METHODS: Seventy five children aged 6 months to 12 yr with signs of community-acquired lower respiratory tract infections were selected for the study. Culture of nasopharyngeal aspirates was done. The serum samples were analyzed for the detection of IgM and IgG antibodies to M. pneumoniae. A 543 base pairs (bp) region of P1 gene of M. pneumoniae was selected for amplification in PCR assay applied to nasopharyngeal aspirates. RESULTS: M. pneumoniae was isolated in culture from 4 (5.33%) children. Serological evidence of M. pneumoniae infection was observed in 16(21.3%) children. All culture positive patients were also positive by serology. Overall, PCR for M. pneumoniae was positive in 13 (17.3%) patients. All four culture positive patients were also positive by PCR. In 11 out of 13 (84.62%) PCR positive patients, serological evidence was there. Culture and/or serology and/or PCR positive results diagnosed M. pneumoniae infection in 18 (24%) of 75 patients. INTERPRETATION & CONCLUSION: A combination of culture, serology and PCR may provide diagnostic information on the aetiology of M. pneumoniae community-acquired lower respiratory tract infections in paediatric population.

The seroepidemiological study on cytomegalovirus in women of child-bearing age with special reference to pregnancy and maternal-fetal transmission.

We screened 500 women of childbearing age belonging to different socioeconomic class for the presence of IgM antibodies against cytomegalovirus (CMV) infection by ELISA. Among these were 70 pregnant women, positive for CMVspecific IgM antibodies, whose newborns were also tested for the same. IgM positivity was found to be 5.4% (27/500) while 2.2% (11/500) gave equivocal results. There was an increasing trend in IgM positivity with age, decreasing socioeconomic status and increasing parity. Prevalence rate was more in women from rural as compared to those of urban area. Among the pregnant women, in the higher income group, 4 (14.28%) had CMV specific IgM antibodies as compared to 9 (21.43%) of low income. Congenital infection occurred more often (14.28 vs 7.14%) in infants in low income group. Signs and symptoms compatible with acute CMV infection were found in 7.69% (1/13) women and 27.78% (5/18) newborns. Thus the need for screening and protection against this infection is further emphasized.