title: Hospital air: A potential route for transmission of infections caused by β-lactam-resistant bacteria.
abstract: The emergence of bacterial resistance to β-lactam antibiotics seriously challenges the treatment of various nosocomial infections. This study was designed to investigate the presence of β-lactam-resistant bacteria (BLRB) in hospital air.
  
  
  
  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 β-lactams. BLRB isolates were screened for the presence of 5 common β-lactamase-encoding genes. Sequence analysis of predominant BLRB was also performed.
  
  
  
  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 β-lactamase-encoding 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.
  
  
  
  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.
authors.affiliation: Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran; Student Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Environmental Health Engineering, School of Health, Arak University of Medical Sciences, Arak, Iran.
authors.forename: Seyed Hamed
authors.initials: SH
authors.lastname: Mirhoseini
authors.affiliation: Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran. Electronic address: nikaeen@hlth.mui.ac.ir.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Nikaeen
authors.affiliation: Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran; Student Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Shamsizadeh
authors.affiliation: Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Khanahmad
mesh_terms: D000391:Air Microbiology; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000635:transmission; D003428:Cross Infection / Q000635:transmission; D018562:Disease Transmission, Infectious; D006761:Hospitals; D006801:Humans; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D001618:beta-Lactamases
keywords: Airborne; antibiotic-resistant bacteria; hospital; nosocomial infection; β-lactam