Occurrence of airborne vancomycin- and gentamicin-resistant bacteria in various hospital wards in Isfahan, Iran


1 Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran

2 Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

3 Department of Statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran


Background: Airborne transmission of pathogenic resistant bacteria is well recognized as an important route for the acquisition of a wide range of nosocomial infections in hospitals. The aim of this study was to determine the prevalence of airborne vancomycin and gentamicin (VM and GM) resistant bacteria in different wards of four educational hospitals.
Materials and Methods: A total of 64 air samples were collected from operating theater (OT), Intensive Care Unit (ICU), surgery ward, and internal medicine ward of four educational hospitals in Isfahan, Iran. Airborne culturable bacteria were collected using all glass impingers. Samples were analyzed for the detection of VM- and GM-resistant bacteria.
Results: The average level of bacteria ranged from 99 to 1079 CFU/m3. The highest level of airborne bacteria was observed in hospital 4 (628 CFU/m3) and the highest average concentration of GM- and VM-resistant airborne bacteria were found in hospital 3 (22 CFU/m3). The mean concentration of airborne bacteria was the lowest in OT wards and GM- and VM-resistant airborne bacteria were not detected in this ward of hospitals. The highest prevalence of antibiotic-resistant airborne bacteria was observed in ICU ward. There was a statistically significant difference for the prevalence of VM-resistant bacteria between hospital wards (P = 0.012).
Conclusion: Our finding showed that the relatively high prevalence of VM- and GM-resistant airborne bacteria in ICUs could be a great concern from the point of view of patients' health. These results confirm the necessity of application of effective control measures which significantly decrease the exposure of high-risk patients to potentially airborne nosocomial infections.


Mirhoseini SH, Nikaeen M, Khanahmad H, Hatamzadeh M, Hassanzadeh A. Monitoring of airborne bacteria and aerosols in different wards of hospitals – Particle counting usefulness in investigation of airborne bacteria. Ann Agric Environ Med. 2015;22:670-3.  Back to cited text no. 1
Ahmed Z, Saeed Khan S, Khan M.In vitro trials of some antimicrobial combinations against Staphylococcus aureus and Pseudomonas aeruginosa. Saudi J Biol Sci 2013;20:79-83.  Back to cited text no. 2
Chambers HF, Deleo FR. Waves of resistance: Staphylococcus aureus in the antibiotic era. Nat Rev Microbiol 2009;7:629-41.  Back to cited text no. 3
Bockstael K, Van Aerschot A. Antimicrobial resistance in bacteria. Cent Eur J Med 2009;4:141-55.  Back to cited text no. 4
Fiegel J, Clarke R, Edwards DA. Airborne infectious disease and the suppression of pulmonary bioaerosols. Drug Discov Today 2006;11:51-7.  Back to cited text no. 5
Tang JW, Li Y, Eames I, Chan PK, Ridgway GL. Factors involved in the aerosol transmission of infection and control of ventilation in healthcare premises. J Hosp Infect 2006;64:100-14.  Back to cited text no. 6
Dürmaz G, Kiremitçi A, Akgün Y, Oz Y, Kasifoglu N, Aybey A, et al. The relationship between airborne colonization and nosocomial infections in intensive care units. Mikrobiyol Bul 2005;39:465-71.  Back to cited text no. 7
Jana S, Deb JK. Molecular understanding of aminoglycoside action and resistance. Appl Microbiol Biotechnol 2006;70:140-50.  Back to cited text no. 8
Askari E, Zarifan A, Pourmand MR, Naderi-Nasab M. High-level vancomycin-resistant Staphylococcus aureus (VRSA) in Iran: A systematic review. J Med Bacteriol 2012;1:53-61.  Back to cited text no. 9
Saderi H, Owlia P, Shahrbanooie R. Vancomycin resistance among clinical isolates of Staphylococcus aureus. Arch Iran Med 2005;8:100-3.  Back to cited text no. 10
Aligholi M, Emaneini M, Jabalameli F, Shahsavan S, Dabiri H, Sedaght H. Emergence of high-level vancomycin-resistant Staphylococcus aureus in the Imam Khomeini Hospital in Tehran. Med Princ Pract 2008;17:432-4.  Back to cited text no. 11
Rice LB. Antimicrobial resistance in gram-positive bacteria. Am J Infect Control 2006;34 5 Suppl 1:S11-9.  Back to cited text no. 12
Rosvoll TC, Lindstad BL, Lunde TM, Hegstad K, Aasnaes B, Hammerum AM, et al. Increased high-level gentamicin resistance in invasive Enterococcus faecium is associated with aac(6') Ie-aph(2'') Ia-encoding transferable megaplasmids hosted by major hospital-adapted lineages. FEMS Immunol Med Microbiol 2012;66:166-76.  Back to cited text no. 13
Gilbert Y, Veillette M, Duchaine C. Airborne bacteria and antibiotic resistance genes in hospital rooms. Aerobiologia 2010;26:185-94.  Back to cited text no. 14
Muzslay M, Moore G, Turton JF, Wilson AP. Dissemination of antibiotic-resistant enterococci within the ward environment: The role of airborne bacteria and the risk posed by unrecognized carriers. Am J Infect Control 2013;4:57-60.  Back to cited text no. 15
CLSI. Performance Standards for Antimicribial Sucseptibility Testing Twenty – Second Informational Supplement. Wayne, PA: CLSI Document M100-S22; 2012.  Back to cited text no. 16
Beggs CB. The airborne transmission of infection in hospital buildings: Fact or fiction? Indoor Built Environ 2003;12:9-18.  Back to cited text no. 17
Nourmoradi H, Nikaeen M, Amin MM, Hatamzadeh M. An investigation on bio-aerosol concentrations in the different wards of hospitals of Isfahan university of medical sciences. J Isfahan Med Sch 2011;29:1028-36.  Back to cited text no. 18
Ortiz G, Yagüe G, Segovia M, Catalán V. A study of air microbe levels in different areas of a hospital. Curr Microbiol 2009;59:53-8.  Back to cited text no. 19
Hoseinzadeh E, Samarghandie MR, Ghiasian SA, Alikhani MY, Roshanaie G. Evaluation of bioaerosols in five educational hospitals wards air in Hamedan, during 2011-2012. Jundishapur J Microbiol 2013; 6:e10704.  Back to cited text no. 20
Carlet J, Ben Ali A, Chalfine A. Epidemiology and control of antibiotic resistance in the intensive care unit. Curr Opin Infect Dis 2004;17:309-16.  Back to cited text no. 21
Varley AJ, Williams H, Fletcher S. Antibiotic resistance in the intensive care unit. Contin Educ Anaesth Crit Care Pain 2009;9:114-8.  Back to cited text no. 22
Rossi F, Diaz L, Wollam A, Panesso D, Zhou Y, Rincon S, et al. Transferable vancomycin resistance in a community-associated MRSA lineage. N Engl J Med 2014;370:1524-31.  Back to cited text no. 23
Xu HT, Tian R, Chen DK, Xiao F, Nie ZY, Hu YJ, et al. Nosocomial spread of hospital-adapted CC17 vancomycin-resistant Enterococcus faecium in a tertiary-care hospital of Beijing, China. Chin Med J (Engl) 2011;124:498-503.  Back to cited text no. 24
Hiramatsu K, Katayama Y, Matsuo M, Sasaki T, Morimoto Y, Sekiguchi A, et al. Multi-drug-resistant Staphylococcus aureus and future chemotherapy. J Infect Chemother 2014;20:593-601.  Back to cited text no. 25
Otter JA, Yezli S, French GL. The role played by contaminated surfaces in the transmission of nosocomial pathogens. Infect Control Hosp Epidemiol 2011;32:687-99.  Back to cited text no. 26
Savini V, Gherardi G, Astolfi D, Polilli E, Dicuonzo G, D'Amario C, et al. Insights into airway infections by enterococci: A review. Recent Pat Antiinfect Drug Discov 2012;7:36-44.  Back to cited text no. 27
Willems RJ, Top J, van Santen M, Robinson DA, Coque TM, Baquero F, et al. Global spread of vancomycin-resistant Enterococcus faecium from distinct nosocomial genetic complex. Emerg Infect Dis 2005;11:821-8.  Back to cited text no. 28
Tomita H, Pierson C, Lim SK, Clewell DB, Ike Y. Possible connection between a widely disseminated conjugative gentamicin resistance (pMG1-like) plasmid and the emergence of vancomycin resistance in Enterococcus faecium. J Clin Microbiol 2002;40:3326-33.  Back to cited text no. 29
Feizabadi MM, Maleknejad P, Asgharzadeh A, Asadi S, Shokrzadeh L, Sayadi S. Prevalence of aminoglycoside-modifying enzymes genes among isolates of Enterococcus faecalis and Enterococcus faecium in Iran. Microb Drug Resist 2006;12:265-8.  Back to cited text no. 30
Gad GF, Mohamed HA, Ashour HM. Aminoglycoside resistance rates, phenotypes, and mechanisms of Gram-negative bacteria from infected patients in upper Egypt. PLoS One 2011;6:e17224.  Back to cited text no. 31
Simonsen GS, Småbrekke L, Monnet DL, Sørensen TL, Møller JK, Kristinsson KG, et al. Prevalence of resistance to ampicillin, gentamicin and vancomycin in Enterococcus faecalis and Enterococcus faecium isolates from clinical specimens and use of antimicrobials in five Nordic hospitals. J Antimicrob Chemother 2003;51:323-31.  Back to cited text no. 32