Indoor air bacterial load and antibiotic susceptibility pattern of isolates at Adare General Hospital in Hawassa, Ethiopia

Abstract

Background Air is the agent of pathogenic microbes that cause significant problems in the hospital environment. Multidrug resistance poses a major therapeutic challenge to these airborne microorganisms in hospital indoor environments. Method and materials This study was conducted at Adare General Hospital in Hawassa City, Sidama, Ethiopia. A cross-sectional study was conducted. The proportional allocation method was used to select the sampled 50 rooms from the total available rooms in each category of wards and staff offices. A total of 100 indoor air samples were collected using settle plates in all units twice a day, morning (9:00–4:00 a.m.) and afternoon (3:00–4:00 p.m.). The types and number of colonies were determined in the laboratory, and the pathogenic bacteria were isolated by appropriate bacteriological techniques. Antimicrobial susceptibility testing was performed on Mueller-Hinton agar for each potentially pathogenic bacterium isolated. For each bacterium, a total of 12 antibiotics were tested using the Kirby-Bauer disk diffusion method. The test organism was adjusted to McFarland turbidity standards of 0.5. Data were entered and analyzed using the SPSS version 25 window. Descriptive analysis and one-way analysis of variance were performed. Results The indoor air bacterial load of Adare General Hospital was found in the range between 210 and 3,224 CFU/m 3 . The highest indoor air bacterial load was identified from the gynecology ward with a mean of 2,542.5CFU/m 3 at p < 0.05. From 100 indoor air samples, a total of 116 bacterial pathogen isolates were obtained. Gram-positive isolates predominated at 72.4%, of which 37.1% were Staphylococcus aureus , 26.7% were coagulase-negative Staphylococci , and the rest 8.6% were Streptococcus pyogenes . The isolation of pathogenic bacteria Staphylococcus aureus and coagulase-negative Staphylococci showed a high level of resistance to ampicillin. Conclusion A high bacterial load was found in the study area as compared to different indoor air biological standards. Staphylococcus aureus and coagulase-negative Staphylococci were the isolated predominant bacteria. Attention should be given to preventing and minimizing those environmental factors that favor the multiplication of bacteria in the indoor environment of a hospital for the safe health of patients, visitors, and staff.