Microbiology
Mehrdad Gholami; Mohammadreza Haghshenas; Mona Moshiri; Shbnam Razavi; Abazar Pournajaf; Gholamreza Irajian; Mohsen Heidary
Abstract
Background & objective: Multidrug-resistant Acinetobacter baumannii (MDR-AB) is an important nosocomial pathogen which is associated with significant morbidity and mortality, particularly in high-risk populations. Aminoglycoside-modifying enzymes (AMEs) and 16S ribosomal RNA (16S rRNA) ...
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Background & objective: Multidrug-resistant Acinetobacter baumannii (MDR-AB) is an important nosocomial pathogen which is associated with significant morbidity and mortality, particularly in high-risk populations. Aminoglycoside-modifying enzymes (AMEs) and 16S ribosomal RNA (16S rRNA) methylation are two important mechanisms of resistance to aminoglycosides. The aim of this study was to determine the prevalence of 16S rRNA methylase (armA, rmtA, rmtB, rmtC, and rmtD), and the AME genes [aac(6′)-Ib, aac(3)-I, ant(3′′)-I, aph(3′)-I and aac(6')-Id], among clinical isolates of A. baumannii in Tehran, Iran. Methods: Between November 2015 to July 2016, a total of 110 clinical strains of A. baumannii were isolated from patients in two teaching hospitals in Tehran, Iran. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute guidelines. The presence of genes encoding the AMEs and16S rRNA methylases responsible for resistance was investigated by multiplex polymerase chain reaction. Results: The results showed that colistin was an effective antibiotic and could be used as a last-resort treatment of infections caused by MDR-AB. The resistance rate to aminoglycosides were 100%, 96.36% and 90.9% for tobramycin, gentamicin and amikacin, respectively. In this study, AME genes of aac(6′)-Ib, aac(3)-I and ant(3′′)-I were most prevalent among the isolated strains. Conclusion Markedly high resistance to tobramycin, gentamicin and amikacin was noted in current study. Our results suggested that modifying enzyme genes in conjunction with methylation of 16S rRNA might contribute to aminoglycoside resistance induced in vivo in A. baumannii.Further studies are required to determine the prevalence of the aminoglycoside resistance genes in other hospitals of Iran.
Maryam Amini; Ali Davati; Mahdieh Golestanifard
Volume 7, Issue 4 , September 2012, , Pages 241-245
Abstract
Background and Objective:Acinetobacter spp.a Gram-negative coccobacillus is increasingly reported as important cause of nosocomial infections. Multi-drug resistance (MDR) ofAcinetobacterspp., raises concerns over our ability to treat serious infections with these organisms. The aim of this study was ...
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Background and Objective:Acinetobacter spp.a Gram-negative coccobacillus is increasingly reported as important cause of nosocomial infections. Multi-drug resistance (MDR) ofAcinetobacterspp., raises concerns over our ability to treat serious infections with these organisms. The aim of this study was to determine the frequency and associated risk factors for infections with MDR Acinetobacter spp. in ICU patients ofShahid Mostafa Khomeini Hospital, Tehran, Iran.
Patients and Methods:This descriptive-analytical andcross-sectional study was designed in 3 years period from April 2008 to March 2010 on 130 patients. For bacteriological analysis, sputum, blood, urine and wound specimens were used from patients within >48 hr after admission. Patient’s clinical and epidemiologic data were collected, from recordedfile, and correlated to Acinetobacter spp. infection. The data were analyzed using SPSS16 statistical software,chi-square, and Mann-Whitney test.
Results: The frequency of Acinetobacterspp. infection separately by years was 21.5%, 30.8% and 47.7% in 2008, 2009, 2010, respectively. All isolateswere resistant to carbnicillin, piperacillin, cefotaxime and cephalotin, 99.2% to ciprofloxacin, cotrimoxazole and chloramphenicol, 97.7% to imipenem, 95.4% to tetracycline and 91.5% to gentamicin. The highest sensitivity was to amikacin 14.6%.
Conclusion:Nosocomialinfections with Acinetobacter spp. during the three years, was a growing trend, and all isolates were MDR and highest susceptibility was to Amikacin. Most important risk factors wereincorrect diagnosis, inappropriate usage, doses, andtime of antibiotic therapy, inappropriate formulation of some antibiotics.
