Hospital air: A potential route for transmission of infections caused by beta-lactam-resistant bacteria

Abstract

Background: The emergence of bacterial resistance to beta-lactam antibiotics seriously challenges the treatment of various nosocomial infections. This study was designed to investigate the presence of beta-lactam-resistant bacteria (BLRB) in hospital air. Methods: A total of 64 air samples were collected in 4 hospital wards. Detection of airborne bacteria was carried out using culture plates with and without beta-lactams. BLRB isolates were screened for the presence of 5 common beta-lactamase-encoding genes. Sequence analysis of predominant BLRB was also performed. Results: The prevalence of BLRB ranged between 3 and 34. Oxacillin-resistant bacteria had the highest prevalence, followed by ceftazidime-and cefazolin-resistant bacteria. The frequency of beta-lactamaseencoding genes in isolated BLRB ranged between 0 and 47, with the highest and lowest detection for OXA-23 and CTX-m-32, respectively. MecA had a relatively high frequency in surgery wards and operating theaters, whereas the frequency of blaTEM was higher in intensive care units and internal medicine wards. OXA-51 was detected in 4 wards. Acinetobacter spp, Acinetobacter baumannii, and Staphylococcus spp were the most predominant BLRB. Conclusions: The results revealed that hospital air is a potential route of transmission of BLRB, such as Acinetobacter and Staphylococcus, 2 important causative agents of nosocomial infections. Therefore, improvement of control measures against the spreading of airborne bacteria in hospital environments is warranted. (C) 2016 Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc.