Extended spectrum and metalo beta-lactamase producing airborne Pseudomonas aeruginosa and Acinetobacter baumanii in restricted settings of a referral hospital: a neglected condition

BACKGROUND: Frequently encountered multidrug-resistant bacterial isolates of P. aeruginosa and A. baumannii are common and prevalent in a hospital environment. The aim of this study was to determine the prevalence and pattern of antibiotic resistance, extended spectrum and metallo beta-lactamase producing P. aeruginosa and A. baumannii isolates from restricted settings of indoor air hospital environment. METHODS: A hospital-based cross-sectional study was conducted in Wolaita Sodo University Teaching and referral Hospital, Ethiopia from December 1/2015 to April 30/2015. The Air samples were collected from delivery room, intensive care unit and operation theatre of the hospital by active, Anderson six slate sampler technique during the first week of the months, twice a week during Monday’s and Friday’s. Standard microbiological procedures were followed to isolate P. aeruginosa and A. baumannii. Susceptibility testing was performed on isolates using the Kirby-Bauer disk diffusion technique. Extended spectrum beta lactamase production was detected by double disc synergy test and Imipenem-resistant isolates were screened for producing Metallo-beta lactamase. RESULTS: A total number of 216 indoor air samples were collected from the delivery room, intensive care unit, and operation room. Correspondingly, 43 A. baumannii isolates were identified (13 from delivery room, 21 from intensive care unit and 9 from operation room). Likewise 24 P. aeruginosa isolates were obtained (4 from delivery room, 13 from intensive care unit and 7 from operation room). Extended spectrum beta lactamase and metalo-beta lactamase production were observed in 24 (55.8%) and 13 (30.2%) isolates of A. baumannii respectively, whereas P. aeruginosa showed 15 (62.5%) extended spectrum beta lactamase and 9 (37.5%) metallo-beta lactamase production. CONCLUSIONS: Extended spectrum beta lactamase and metallo-beta lactamase producing bacteria in hospital air is a new dimension for specific setting of the study area where antimicrobial resistance is increasing and surgical site infection is prevalent. So, identification of these microorganisms has a great role in reducing the burden of antibiotic resistance and could also provide a significant input for framing hospital infection control policies.