Emergence of OXA-833 in Proteus Species at a Tertiary Care Hospital in Dhaka, Bangladesh

CONTEXT: Proteus species are liable for multitude of infections and associated with resistance to routinely used antibiotics even to reserve drugs such as carbapenems. AIMS: The aim of this study was to detect the presence of MBL producers, including blaOXA-833 gene in Proteus spp. along with their antibiotic resistance pattern. SETTINGS AND DESIGN: This cross-sectional study was conducted in the Department of Microbiology of a tertiary care hospital of Bangladesh during July 2018 to June 2019. SUBJECTS AND METHODS: Proteus spp. was isolated from a total of 500 samples. Antibiotic susceptibility was performed by disk-diffusion technique. Minimum inhibitory concentration (MIC) of imipenem was determined by agar dilution method. Carbapenemase producers were phenotypically detected by double disc synergy (DDS) test, combined disc (CD) assay, and modified Hodge test (MHT). Carbapenemase genes (blaKPC, blaVIM, blaIMP, blaNDM-1, blaOXA-23, blaOXA-48-like/blaOXA-833, and blaOXA-58) among imipenem-resistant Proteus spp. were detected by polymerase chain reaction (PCR). Sequencing was performed to differentiate OXA-833 from OXA-48-like gene by capillary method, and the nucleotide sequence of OXA-833 has been deposited to GenBank. RESULTS: Ten (25%) imipenem-resistant isolates were detected during disk-diffusion technique, among them 60%, 70%, 50% carbapenemase producers were detected by DDS test, CD assay, MHT, respectively, and 70% by PCR. A significant increase in MIC was found between 8 and ≥128 μg/ml to imipenem. PCR revealed that 40% imipenem-resistant isolates were positive for blaNDM-1 and blaVIM followed by 20% for blaOXA-48-like/blaOXA-833 and blaOXA-23, respectively. Sequencing of blaOXA-48-like gene established the OXA-833 variant of class D carbapenemase encoding gene. CONCLUSION: The results of this study showed the presence of high proportion of carbapenemase enzyme-producing Proteus spp. in Bangladesh. blaOXA-833 is emerging in Bangladesh.