Volume 6, Issue 3 (2020)                   IEM 2020, 6(3): 0-0 | Back to browse issues page

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Ahmadian Alashti F, Ghane M. High frequency of 16S ribosomal RNA methyltransferases among aminoglycoside-resistant Klebsiella pneumoniae isolates; first report of rmtA, rmtD, rmtE, and rmtF resistance genes in Iran. IEM. 2020; 6 (3)
URL: http://iem.modares.ac.ir/article-4-44462-en.html
1- Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
2- Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran , ghane@iiau.ac.ir
Abstract:   (178 Views)
Aims: 16S ribosomal RNA methyltransferases (RMTases) confer high-level resistance to aminoglycosides and are increasingly reported among Gram-negative bacilli, especially Klebsiella pneumoniae isolates. The objectives of the present study were to assess the resistance to aminoglycosides, the presence of RMTase genes, and the multilocus sequence typing (MLST) in urinary K. pneumoniae isolates.
Materials & Methods: In this study, 100 K. pneumoniae isolates were tested for susceptibility to amikacin and gentamicin by broth microdilution test according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Then the prevalence of RMTase genes was determined, and alleles and ST type of two selected isolates were identified by MLST. Finally, the isolates were genetically typed using Enterobacterial Repetitive Intergenic Consensus (ERIC) method.
Findings: Broth microdilution assay showed that resistance to amikacin and gentamicin was 70 and 52%, respectively. In addition, 40% of the strains were resistant to both aminoglycosides. Also, rmtC (59.8%) gene was the most common type of RMTase genes investigated, followed by rmtA (51.2%), rmtD (47.6%), rmtF (43.9%), rmtE (41.5%), armA (41.5%), and rmtB (7.3%). K. pneumoniae isolates were assigned into two sequence types: ST51 and ST149. Using ERIC-PCR method, 3-7 different bands and 21 ERIC-PCR profiles were detected among the studied isolates.
Conclusion: The high frequency of aminoglycoside resistance and the increased presence of 16S RMTases in K. pneumoniae strains are of great concern in Iran. Molecular typing showed high genetic diversity among the studied isolates. However, ST51 and ST149 were reported for the first time in Iran and could be considered as emerging strains.
     
Article Type: Original Research | Subject: Bacteriology
Received: 2020/07/14 | Accepted: 2020/08/31 | Published: 2020/08/20

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