Aminoglycoside resistance mechanisms in invasive Klebsiella pneumoniae and Escherichia coli: a threat of rmtC mediated resistance

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Uzun İ., Çelik T., Aksu M. B. , Ülger N. , Hasdemir Gökboğa M. U.

European Congress of Clinical Microbiology and Infectious Diseases, Paris, Fransa, 18 - 21 Nisan 2020, ss.2775

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: Paris
  • Basıldığı Ülke: Fransa
  • Sayfa Sayıları: ss.2775


Background: Aminoglycosides (Ags) are often used in combination with other antibiotics and provide a valuable therapeutic option for treating multidrug resistant bacterial infections. Aminoglycoside resistance (AgR) due to 16S ribosomal methyltransferases (RMTs) seems to emerge as real threat that limit the use of these antibiotics for salvage therapy. In this study, we aimed to investigate genetic determinants of RMTs together with aminoglycoside modification enzymes (AgMEs) in invasive Klebsiella pneumoniae and Escherichia coli. Materials/methods: Fifty K. pneumoniae and 49 E. coli, isolated throughout the year 2016 and exhibited resistance to at least amikacin or gentamicin in routine susceptibility testing (VITEK® 2 Compact, BioMérieux, France) were included in the study. Amikacin, gentamicin, tobramycin, and netilmicin MICs of the isolates were determined by standard broth microdilution method (BMD) in the study isolates. Genetic determinants of RMTs (armA, rmtA, rmtB, rmtC, rmtD, rmtE, rmtF, rmtG, rmtH, npmA) and AgMEs [aac(3)-II, aac(3)-I, aac(6’)-Ib, ant(2’’)-I] were investigated by PCR. Results: Twelve of 50 (24%) K. pneumoniae isolates exhibited high level resistance (>256 mg/L) to all Ags tested in BMD. High level aminoglycoside resistance was not detected in any of the E. coli isolates. rmtC was the most common (13/50) RMT gene followed by armA (2/50) in K. pnuemoniae (Table 1). aac(3)-II was found together with aac(6’)-Ib in 64% of K. pneumoniae and 32.7% of E. coli isolates. Conclusions: rmtC encoded high level aminoglycoside resistance seems to be a threat in K. pneumoniae in our hospital, especially considering high risk of multidrug resistance in such isolates.