Seroprevalence of anti-Chlamydia trachomatis IgM in neonatal respiratory tract infections in Hungary.

Purpose. To determine the seroprevalence of specific IgM indicative of respiratory tract infection (RTI) due to Chlamydia trachomatis (CT) among symptomatic infants.Methodology. A descriptive study was conducted on young infants up to 5 months old at the Bacterial Sexually Transmitted Infections Reference Laboratory, National Centre for Epidemiology, Budapest, covering the period 2008-2016. Serum samples from infants suffering from RTIs were screened with a micro-immunofluorescence test (Focus, Cypress, USA) for the presence of anti-Chlamydia trachomatis-specific IgM. A parallel Bordetella pertussis screening was performed by an indirect immunofluorescence test (Euroimmun, Lübeck, Germany) that detected specific IgM.Results.The CT-specific serum IgM was highly reactive in 50 (19.1 %) of the 262 neonates with RTIs, while all proved negative for Bordetella pertussis-specific IgM.Conclusion. Vertically transmitted C. trachomatis must be regarded as a common pathogen among symptomatic neonates with RTIs in Hungary. Routine screening and treatment of pregnant women could be one option to help prevent these conditions. Focused laboratory testing based on raised clinical awareness should enable early diagnosis and appropriate therapy for symptomatic infants.