Detection of OXA-23 Gene in Amoxicillin-Clavulanic Acid-resistant Proteus mirabilis Isolates in Turkey

Class D carbapenemases, including OXA-23, OXA24/40, OXA-51, OXA-58, and OXA143, are typically associated with Acinetobacter species; OXA-48-like carbapenemases are usually found in Enterobacterales isolates. Although a few studies on Acinetobacter-type OXA genes in Enterobacterales have been reported, the presence of these Acinetobacter-type OXA genes in these isolates is quite limited. In contrast to other Enterobacterales isolates, studies have identified the presence of genes OXA-23, OXA-24, OXA-51, and OXA-58, which are typically associated with Acinetobacter species, Proteus mirabilis. This study aimed to investigate the presence of carbapenemase genes in amoxicillin-clavulanic acid-resistant P. mirabilis isolates. Thirty-two P. mirabilis isolates isolated from samples sent from intensive care patients and resistant to amoxicillin-clavulanic acid were included in the study. Vitek MS was used for bacterial identification, and the antibiotic resistance profile was determined by the Vitek 2 automated system. The presence of Acinetobacter type OXA genes (OXA-23, OXA-24, OXA-51, and OXA-58) and OXA-48, KPC, NDM, VIM, and IMP genes in P. mirabilis strains were investigated by polymerase chain reaction (PCR) method. In addition, ESBL production was detected in carbapenemase gene-positive isolates. According to the PCR results, while the presence of the OXA23 gene was detected in 15.6% of the isolates, the presence of OXA-24, OXA-51, OXA-58, OXA-48, KPC, NDM, VIM and IMP genes was not detected in any of the isolates. OXA-23, OXA-24, OXA-51, and OXA-58 are common carbapenemases in Acinetobacter species, especially OXA-23 is very common. However, these genes are very rare in Enterobacterales isolates. There are studies in which these genes were identified in P. mirabilis isolates. Similarly, in our research, the OXA-23 gene was detected in P. mirabilis isolates. To our knowledge, this is the first OXA-23 positivity reported in P. mirabilis isolates from our country.