Iranian CA-MRSA strains are genetically diverse with an elevated prevalence of t790/ST22 SCCmec IV isolates. These findings support the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of CA-MRSA in Iran.
ObjectivesHorizontal transfer of integrons is one of the important factors that can contribute to the occurrence of multidrug-resistant (MDR) bacteria. This study aimed to determine the prevalence of integrons among MDR Escherichia coli strains isolated from stool specimens and investigate the associations between the existence of integrons and MDR properties in the southwest of Iran.MethodsThere were 164 E. coli strains isolated from January 2012 to June 2012. Fecal specimens identified as E. coli by the conventional methods. Subsequently the antibiotic resistance was assessed using Clinical and Laboratory Standard Institute criteria. The presence of class 1–3 integrons and embedded gene cassettes was verified using specific primers by multiplex polymerase chain reaction assay.ResultsAmong a total of 164 studied samples, 69 (42.07%) isolates were multidrug resistant. Class 1 and class 2 integrons were present in 78.26% and 76.81% MDR isolates, respectively. For the first time in Iran, class 3 integron was observed in 26.09% MDR isolates. Significant correlations were identified between: class 1 integron and resistance to amikacin, gentamicin, chloramphenicol, ampicillin, tetracycline, nalidixic acid, and co-trimoxazole; class 2 integron and resistance to aminoglycosides, co-trimoxazole, cefalexin, ampicillin, and chloramphenicol; and class 3 integron and resistance to gentamicin, kanamycin, and streptomycin.ConclusionOur results indicate that integrons are common among MDR isolates and they can be used as a marker for the identification of MDR isolates. Therefore, due to the possibility of a widespread outbreak of MDR isolates, molecular surveillance and sequencing of the integrons in other parts of the country is recommended.
Background:Acinetobacter baumannii has emerged as a cause of nosocomial infections in hospitalized patients, particularly in intensive care units. Carbapenems are a common choice for treating nosocomial infections caused by A. baumannii strains. Increasing antimicrobial resistance among Acinetobacter isolates has been documented and multidrug-resistant A. baumannii is recognized to be among the most difficult antimicrobial-resistant bacilli to control and treat. Objectives: This study describes carbapenem resistance in A. baumannii isolates obtained during an outbreak from intensive care units of a peripheral hospital in central part of Iran. Patients and Methods: Sixty-three non-repetitive A. baumannii isolates were collected over a six months period. Susceptibility of the isolated bacteria to a panel of 23 different antimicrobial agents was defined by using the standard disk diffusion method. Production of Metallo-β-lactamases (MBL) and AmpC β-lactamase were determined by using the E-test MBL strip and AmpC disk tests, respectively. Results: The present study indicates that carbapenems and new cephalosporin antibiotics were practically ineffective against the extensive drug resistance (XDR) strains. Colistin was observed to be more effective, although in seven cases resistance to colistin observed. AmpC β-lactamase and MBL could be an important contributory factor for imipenem resistance among the isolates in our hospital. The elevated prevalence of XDR and pan drug resistance (PDR) strains indicates that local antibiotic prescription policies should be revised and infection control should be improved.
Conclusions:The elevated prevalence of XDR and PDR strains indicates that local antibiotic prescription policies should be revised and infection control should be improved.
BackgroundTo investigate antibiotic resistance, the occurrence and distribution of class 1 and 2 integrons in multidrug- resistant Staphylococcus aureus isolates from hospitals in Tehran, Iran.The isolates were examined for susceptibility to antimicrobial agents. The mecA gene, class 1 and 2 integrons were detected by PCR. Integrase positive strains were further analysed for the presence of resistance gene cassettes using specific primers and were sequenced.ResultsAmong 139 S.aureus isolates, 109 (78.4 %) and 112 (80.5 %) strains were considered as multidrug resistant and mecA positive, respectively. Class 1 integrons and internal variable regions were found in 72.6 % (101/139) and 97 % (98/101) and class 2 integrons and variable regions also in 35.2 % (49/139) and 65.3 % (32/49) of S.aureus clinical isolates, respectively. Twelve distinct cassette arrays were found, containing genes encoding resistance to β-lactams, aminoglycosides, streptothricin, trimethoprim, chloramphenicol,a putative glucose dehydrogenase precursor and a protein with unknown function. Gene cassette arrays aadB, aadA2 and dhfrA1-sat2-aadA1 were common in S.aureus isolates. We detected a completely new gene cassettes which contained aadB, oxa2, aacA4, orfD-aacA4-catB8, aadB-catB3, orfD-aacA4 and aadB-aadA1-cmlA6 of class 1 and dhfrA1-sat2-aadA1, dhfrA11, dhfrA1-sat2 of class 2 integrons.ConclusionsThis is the first study to report carriage of class 1 and 2 integrons and associated gene cassettes among in S.aureus isolates from Iran.
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