EMERGENCE OF CARBAPENEM RESISTANT RAOULTELLA ORNITHINOLYTICA ISOLATES CO-HARBORING BLANDM-1 AND BLAOXA-48

Atul Khajuria* and Ashok Kumar Praharaj

ABSTRACT

Objective: To examine the distribution, emergence and spread of genes encoding beta-lactamase resistance in R.ornithinolytica recovered from hospitalized patients in a tertiary care hospital. Methods: A prospective study was conducted in an 1800 bedded tertiary care centre in Pune, India from October 2013 to October 2017. A total of 13isolates were recovered from clinical specimens of hospitalized patients admitted to the Medical and Surgical intensive care units (one isolate per patient). Polymerase chain reaction (PCR) assays and sequencing was used to determine the presence of beta-lactamase encoding genes and conjugation experiments were performed to determine the transferability. Isolate relatedness were determined by REP PCR, ERIC PCR and RAPD. Results: A total of 13 R.ornithinolytica isolates were recovered, largest proportion of specimens were from UTIs 38.5%, followed by 23% in IAIs, 15.4% in both BSIs, and SSTIs and 7.7% in RTIs, respectively. Among 13 tested isolates, 84.6% isolates showed MIC >4μg/ml against imipenem and meropenem. Of the total number of samples, males contributed 38.5% while females contributed 61.5%. Of the total samples, highest 61.5% were from ICU Surgery followed by 38.5% in ICU Medical. Majority of Carbapenem resistant R.ornithinolytica 45.6% were from UTIs, followed by 18.2% in both BSIs, and SSTIs, and 9% in both IAIs, and RTIs, respectively. MHT, DDST, CDST, and MBL(IP/IPI) E-test was positive in 84.6% isolates. 100% R.ornithinolytica isolates retained susceptible to polimixin and colistin. Conjugation experiments indicated that blaNDM-1, blaOXA-48, blaSHV-12, blaSHV-28, blaCTX-M-15, blaCTX-M-14 were transferable via plasmid. Conclusion: This study highlights prevalence of blaOXA-48 & blaNDM-1 producing R.ornithinolytica along with other β-lactamases genes carried on a single or multiple plasmids that serve as a driving force for the horizontal spread of carbapenem resistance.

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