Isolation and Antibiotic Susceptibility Patterns of Airborne Bacteria from the In-Patient and Out-Patient Sections of Selected Primary Health Care Centers

Airborne bacteria constitute an important source of environmental contamination in healthcare facilities and may contribute to healthcare-associated infections. This study assessed the load, diversity and antibiotic susceptibility of settled airborne bacteria in the in-patient (IP) and out-patient (OP) sections of six primary health care centres (three government-owned and three private-owned) in Obafemi-Owode LGA, Ogun State, Nigeria. Settle plates (Nutrient and MacConkey agar) were exposed in triplicate at 150 cm for 10-, 20- and 30-min during morning clinics across four wet-season visits (June 2025). OP loads were significantly higher than IP loads (one-way ANOVA, P < 0.05), with overall means of 21.1±4.58 and 65.2±7.06 CFU/plate, respectively (grand mean 43.1±7.77). After 48 h, IP counts ranged from 8±0.63 – 22±2.71 (10 min), 11±0.91 – 52±4.16 (20 min) and 16±1.31 – 57±2.36 CFU/plate (30 min); OP counts were 22±0.71 – 54±2.76, 36±2.46 – 104±3.89 and 82±2.23 – 144±5.16. The highest OP means were at IHC (86.7±17.28) and OHC (82.7±17.92); the lowest was at MHC (39.3±10.39). Several government-owned centres showed higher contamination than the private-owned. Gram-positive bacteria predominated, including Staphylococcus spp., Streptococcus spp. and Bacillus spp., alongside Gram-negative genera including Escherichia coli, Klebsiella spp., Pseudomonas spp. and Serratia spp. Mean panel resistance was about 52% (Gram-positive) and 48% (Gram-negative), especially to ampicillin, amoxicillin–clavulanate and erythromycin; while ciprofloxacin and gentamicin showed the best activity. The data indicate substantial settled airborne contamination that may increase healthcare-associated infection risk and underscore the need for routine microbiological surveillance, improved ventilation, and stringent infection-prevention protocols