title: Drug resistance patterns of bacteria isolated from patients with nosocomial pneumonia at Tehran hospitals during 2009-2011.
abstract: BACKGROUND
  Nosocomial pneumonia remains an important cause of mortality and morbidity worldwide. Surveillance programs play an important role in the identification of common etiologic agents and local patterns of antimicrobial resistance.
  
  
  METHODS
  In this study we determined the frequency and antimicrobial susceptibility of pathogens isolated from patients with nosocomial pneumonia during 2009 to 2011.
  
  
  RESULTS
  A total of 642 bacteria were isolated from 516 suspected samples. Acinetobacter baumannii (21.1%, n = 136), was the commonest isolated pathogen followed by Pseudomonas aeruginosa (17.4%, n = 112), Staphylococcus aureus (15.8%, n = 102) and enterococci (8.4% n = 54). The most effective therapeutic agents against A. baumannii were polymyxin B (95.5% susceptible), ceftriaxone/tazobactam (72% susceptible) and levofloxacin (52.9% susceptible). Polymixin B (89.2% susceptible), ceftriaxone/tazobactam (89.2% susceptible) and piperacillin-tazobactam (80.3% susceptible) were found to be the most active agents against P. aeruginosa. Extended-spectrum beta-lactamases were detected among isolates of K. pneumoniae (45.4%) and E. coli (20.3%). Overall, the prevalence of methicillin-resistant S. aureus and vancomycin resistant enterococci were 80.4% and 40.7% respectively. Linezolid was found to be the most active antibiotic against these pathogens. The etiology of 50% of the nosocomial infection cases was polymicrobial.
  
  
  CONCLUSIONS
  The combination of ceftriaxone/tazobactam seems to be beneficial agent against multidrug-resistant Gram-negative bacilli isolated form respiratory tract infections. The results of our study can be used for guiding appropriate empiric therapy in this geographic region.
authors.affiliation: Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. m_haeli@yahoo.com
authors.forename: Mehri
authors.initials: M
authors.lastname: Haeili
authors.forename: Arash
authors.initials: A
authors.lastname: Ghodousi
authors.forename: Bijan
authors.initials: B
authors.lastname: Nomanpour
authors.forename: Maryam
authors.initials: M
authors.lastname: Omrani
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Feizabadi
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002443:Ceftriaxone / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D016905:Gram-Negative Bacterial Infections / Q000134:cerebrospinal fluid / Q000453:epidemiology; D016908:Gram-Positive Bacterial Infections / Q000134:cerebrospinal fluid / Q000453:epidemiology; D006761:Hospitals; D006801:Humans; D007492:Iran / Q000453:epidemiology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D000077725:Piperacillin, Tazobactam Drug Combination; D018410:Pneumonia, Bacterial; D011112:Polymyxin B / Q000494:pharmacology; D015995:Prevalence; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000382:microbiology; D013183:Sputum / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D000077725:Piperacillin, Tazobactam Drug Combination; D002443:Ceftriaxone; D010397:Penicillanic Acid; D011112:Polymyxin B; D010878:Piperacillin