Microbiological evaluation of bacterial conjunctivitis in children

Bacterial conjunctivitis is a common condition in paediatric ophthalmology. Incidence and symptoms depend on etiological factor, clinical presentation and age. The most common pathogens which cause bacterial conjunctivitis are: Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis etc. Conjunctivitis is treated empirically in most cases, the treatment is defined by symptoms and clinical findings, physician prescribes the available antibiotic treatment. Eye swab is indicated in cases of prolonged or non efficient treatment or in case of relapse. Goals: To evaluate bacterial conjunctivitis according to microbial pathogen detected in eye swab, the most common microbial pathogens found and drug susceptibility of antimicrobial agents given in antibiogram. Methods: We retrospectively evaluated 73 microbiological findings of eye swabs in 53 children between January 2019 and March 2020. The sample was cultured on blood and chocolate Gram staining agar incubated under 5-10% CO2, 35-37˚C with daily reading 40-48h. Bacteria collected from eye swabs were tested for the following antibiotics: chloramphenicol, ciprofloxacin, gentamicin, moxifloxacin, ofloxacin, trimethoprim/sulfamethoxazole, tetracycline, erythromycin, ampicillin, azithromycin, amoxicillin, clindamycin and penicillin. Results: In a total of 53 patients eye swabs were taken, 23(43,39%) male and 30(56,60%) female, age ranged from 0-17 (mean age 32,3±52,3 months or 2,7±4,4 years) most common patient age was 2 years in 40(75,5%) cases. Number of performed eye swabs was 73, and pathogens were isolated in 70(95,9%) cases, and only in 3(4,1%) cases there were no pathogens in eye swab, meaning that indication for eye swab was highly justified. Among isolated pathogens, Staphylococcus aureus was proved to be the most common, in  20(27,4%) cases, the antibiotic  with highest drug susceptibility was chloramphenicol in 33(62,3%) cases. Conclusion: Microbiological evaluation of bacterial conjunctivitis is reasonable in moderate to severe cases associated with mucopurulent discharge, prolonged treatment, and as confirmation of diagnosis. Choosing the accurate antibiotic therapy requires identification of pathogen and assessing its susceptibility. Targeted treatment reduces risk of antibiotic overdosing or unnecessary use of antibiotics. Prudent use of antibiotics reduces antimicrobial resistance.