title: Monitoring and comparison of antibiotic resistant bacteria and their resistance genes in municipal and hospital wastewaters.
abstract: BACKGROUND
  Human exposure to antibiotic resistant bacteria (ARB) is a public health concern which could occur in a number of ways. Wastewaters seem to play an important role in the dissemination of bacteria and antibiotic resistant genes (ARGs) in our environment. The aim of this study was to evaluate the occurrence of three groups of ARB and their resistance genes in hospital and municipal wastewaters (MWs) as possible sources.
  
  
  METHODS
  A total of 66 samples were collected from raw MWs and hospital wastewaters (HWs) and final effluents of related wastewater treatment plants (WWTPs). Samples were analyzed for the detection of three groups of ARB including gentamicin (GM), chloramphenicol (CHL) and ceftazidime resistant bacteria and their ARGs (aac (3)-1, cmlA1 and ctx-m-32, respectively).
  
  
  RESULTS
  The mean concentration of GM, CHL and ceftazidime resistant bacteria in raw wastewater samples was 1.24 × 10(7), 3.29 × 10(7) and 5.54 × 10(7) colony forming unit/100 ml, respectively. There is a variation in prevalence of different groups of ARB in MWs and HWs. All WWTPs decreased the concentration of ARB. However, high concentration of ARB was found in the final effluent of WWTPs. Similar to ARB, different groups of ARGs were found frequently in both MWs and HWs. All genes also detected with a relative high frequency in effluent samples of MWs WWTPs.
  
  
  CONCLUSIONS
  Discharge of final effluent from conventional WWTPs is a potential route for dissemination of ARB and ARGs into the natural environment and poses a hazard to environmental and public health.
authors.affiliation: Department of Environmental Health Engineering, School of Health, Environment Research Center, Isfahan University of Medical Sciences, Isfahan, Iran ; Department of Environmental Health Engineering, Urmia University of Medical Sciences, Urmia, Iran.
authors.forename: Rahim
authors.initials: R
authors.lastname: Aali
authors.affiliation: Department of Environmental Health Engineering, School of Health, Environment Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Nikaeen
authors.affiliation: Department of Genetics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Khanahmad
authors.affiliation: Department of Statistics and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Hassanzadeh
keywords: Antibiotic resistance genes; antibiotic resistant bacteria; ceftazidim; chloramphenicol; gentamicin
references.citation: J Toxicol Environ Health B Crit Rev. 2007 Dec;10(8):559-73
references.pmid: 18049923
references.citation: Environ Pollut. 2010 Jun;158(6):2101-9
references.pmid: 20356660
references.citation: Antimicrob Agents Chemother. 1997 Jan;41(1):1-6
references.pmid: 8980745
references.citation: Infect Control Hosp Epidemiol. 1997 Jun;18(6):417-21
references.pmid: 9181398
references.citation: Front Microbiol. 2012 Mar 22;3:106
references.pmid: 22461783
references.citation: Int J Hyg Environ Health. 2008 Mar;211(1-2):200-4
references.pmid: 17459769
references.citation: Microbiology (Reading). 2009 Jul;155(Pt 7):2306-2319
references.pmid: 19389756
references.citation: Water Res. 2002 Apr;36(8):1955-64
references.pmid: 12092570
references.citation: Water Res. 2003 Apr;37(8):1685-90
references.pmid: 12697213
references.citation: Curr Opin Microbiol. 2010 Oct;13(5):589-94
references.pmid: 20850375
references.citation: J Environ Manage. 2009 Jun;90(8):2354-66
references.pmid: 19261375
references.citation: Appl Environ Microbiol. 2000 Jan;66(1):453-4
references.pmid: 10618266
references.citation: FEMS Microbiol Ecol. 2009 Apr;68(1):118-30
references.pmid: 19243438
references.citation: Ecotoxicol Environ Saf. 2013 May;91:1-9
references.pmid: 23414720
references.citation: J Environ Manage. 2011 Jan;92(1):250-5
references.pmid: 20884111
references.citation: Microbiology (Reading). 2004 Nov;150(Pt 11):3591-3599
references.pmid: 15528648
references.citation: FEMS Microbiol Rev. 2004 Nov;28(5):519-42
references.pmid: 15539072
references.citation: FEMS Microbiol Lett. 2007 Jun;271(2):147-61
references.pmid: 17490428
references.citation: Water Res. 2011 Nov 1;45(17):5599-611
references.pmid: 21907383
references.citation: Environ Pollut. 2009 Nov;157(11):2893-902
references.pmid: 19560847
references.citation: J Antimicrob Chemother. 2007 May;59(5):841-7
references.pmid: 17332005
references.citation: J Appl Microbiol. 2002;92 Suppl:158S-62S
references.pmid: 12000624
references.citation: Microbiol Mol Biol Rev. 2010 Sep;74(3):417-33
references.pmid: 20805405
references.citation: Anim Biotechnol. 2006;17(2):157-76
references.pmid: 17127527
references.citation: FEMS Microbiol Ecol. 2002 Nov 1;42(2):289-302
references.pmid: 19709289
references.citation: Appl Environ Microbiol. 2009 Sep;75(17):5714-8
references.pmid: 19581476
references.citation: Environ Int. 2012 Jul;42:31-6
references.pmid: 21450343
references.citation: Water Res. 2011 Jan;45(2):681-93
references.pmid: 20850863
references.citation: Appl Environ Microbiol. 2001 Apr;67(4):1494-502
references.pmid: 11282596