Introduction Sexually transmitted infections (STIs) such as Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) are associated with adverse pregnancy and infant outcomes and may also increase the risk of HIV mother-to-child-transmission. Additionally, these infections may be vertically transmitted to neonates, resulting in colonisation, conjunctivitis, and pneumonia. There is a lack of data on the neonatal incidence of CT, NG and TV due to lack of systematic screening of mothers and neonates and reliance on STI syndromic management. We conducted an analysis to determine rates of vertical transmission of CT, NG and TV from HIV-infected women to their neonates.

Methods We tested HIV-infected pregnant women for CT, NG and TV on vulvo-vaginal swab specimens during their first clinic visit post-delivery. Neonates of all women who tested positive for an STI were also evaluated for these STIs using nasopharyngeal swab specimens collected the same day. Testing was done using the Xpert CT/NG and Xpert TV [Cepheid, Sunnyvale, CA].

Results Of the54 women tested for CT, NG and TV postnatally, 27 (50%) had at least one STI. Twenty three (85.2%) of the 27 neonates born to women with STIs were evaluated for STI colonisation. Overall, 18 (78.3%) neonates tested positive for at least one STI; 77.3% (17/22) neonates born to mothers with CT infection, 50% (2/4) with TV, and none with NG tested positive for those respective infections. STI colonisation rates also differed by birth weight with 100% of low birth weight, 77.8% (14/18) with normal birth weight, and 50% (1/2) of high birth weight neonates testing positive for at least one of those infections. Rates of neonatal STI colonisation (83.3%) were also high among the six infants delivered by C-section.

Conclusion Our analysis revealed high rates STIs among postpartum HIV-infected women, coupled with high rates of neonatal STI colonisation, particularly among low birth weight neonates.