The value of simple microbiological studies for on-site screening of acute neonatal conjunctivitis in Angola

Background Neonatal conjunctivitis or ophthalmia neonatorum (ON) is an acute bacterial conjunctivitis contracted by newborns during delivery. In non-industrialized countries, detection of the etiological agent is difficult due to the unavailability of modern diagnostic resources. Therefore, we analyzed the effectiveness of Gram and methylene blue staining techniques, which are simple microbiological methods in suspecting the aetiology of ON in a maternity ward in Luanda, Angola. Findings Neonatal conjunctival smears ( n = 95), maternal data, and perinatal factors were collected. Slides were air-dried and sent to the Microbiology Department of the Hospital Clinico Universitario, Valladolid, Spain, where trained personnel performed Gram and methylene blue staining methods. Findings were interpreted by two expert microbiologists. Ophthalmological examination of all children showed five newborns with clinical signs of ON. Fourteen mothers reported were suspected with vulvo-vaginitis, and 27 had a urinary infection during pregnancy. Gram staining revealed the presence of epithelial cells in 87.6% and leukocytes in 15% of the conjunctival smears. These values were significantly higher than those shown by methylene blue staining. No rods, cocci, or yeasts were identified by either staining method. Chlamydia trachomatis DNA was also undetected in a small sub-sample with clinical suspicion of ON. There was no correlation among the presence of ON, ON microbes, maternal data, or perinatal factors. Conclusions Basic microbiological techniques did not provide enough information for screening cases of ON in Angola. Therefore, the use of molecular biology or other techniques is warranted for this purpose.