Occurrence of NDM-1, VIM-1, and OXA-10 Co-Producing Providencia rettgeri Clinical Isolate in China

Abstract

Providencia rettgeri is a nosocomial pathogen associated with urinary tract infections related to hospital-acquired Infections. In recent years, P. rettgeri clinical strains producing New Delhi Metallo-β-lactamase (NDM) and other β-lactamase which reduce the efficiency of antimicrobial therapy have been reported. However, there are few reports of P. rettgeri co-producing two metallo-β-lactamases in one isolate. Here, we first reported a P. rettgeri strain (P138) co-harboring bla_NDM-1, bla_VIM-1, and bla_OXA-10. The specie were identified using MALDI-TOF MS. The results of antimicrobial susceptibility testing by broth microdilution method indicated that P. rettgeri P138 was resistant to meropenem (MIC = 64μg/ml), imipenem (MIC = 64μg/ml), and aztreonam (MIC = 32μg/ml). Conjugation experiments revealed that the bla_NDM-1-carrying plasmid was transferrable. The carbapenemase genes were detected using PCR and confirmed by PCR-based sequencing. The complete genomic sequence of the P. rettgeri was identified using Illumina (Illumina, San Diego, CA, USA) short-read sequencing (150bp paired-end reads), and many common resistance genes had been identified, including bla_NDM-1, bla_VIM-1, bla_OXA-10, aac(6')-Il, aadA5, ant(2'')-Ia, aadA1, aac(6')-Ib3, aadA1, aph(3')-Ia, aac(6')-Ib-cr, qnrD1, qnrA1, and catA2. The bla_NDM-1 gene was characterized by the following structure: IS110-TnpA-IntI1-aadB-IS91-GroEL-GroES-DsbD-PAI-ble-bla_NDM-1-IS91-QnrS1-IS110. Blast comparison revealed that the bla_NDM-1 gene structure shared >99% similarity with plasmid p5_SCLZS62 (99% nucleotide identity and query coverage). In summary, we isolated a P. rettgeri strain coproducing bla_NDM-1, bla_VIM-1, and blaOXA-10. To the best of our acknowledge, this was first reported in the world. The occurrence of the strain needs to be closely monitored.

Keywords: Mobile gene elements; Providencia rettgeri; blaNDM-1; blaOXA-10; blaVIM-1.