Emergence of OXA-10 and OXA-48 Like Carbapenemases among Enterobacter Isolates from Inpatients in Namazi Hospital in Shiraz

The global spread of carbapenemase-producing Enterobacteriaceae represents a public health concern. This study aimed to investigate the prevalence of carbapenem resistance and the presence of some oxacillinase types and class 1-3 integrons among Enterobacter clinical isolates from an Iranian inpatient population.

Ninety Enterobacter isolates from hospitalized patients were diagnosed by microbiological methods. Antibiogram pattern was also determined. The presence of class 1-3 integrons and four types of oxacillinase genes was assessed using PCR.

Among 90 Enterobacter isolates, the most common species was E. aerogenes, (45.6%), followed by E. cloacae (30%). The highest resistance rate was against ampicillin (96.7%). Multi-drug resistance (MDR) was substantial (93%). Carbapenemase-producers were detected in 96% of carbapenem-resistant isolates by mCIM test. The frequency of evaluated genes was as follows: intI1 = 50 (55.6%), intI2 =12 (13.3%), blaoxa-1 =6 (6.7%), blaoxa-2 =5 (5.6%), blaoxa-10 =18 (20%), and blaoxa-48 =18 (20%).

Determinants of class 1 integron along with OXA-10 and OXA-48 like carbapememases are responsible for relatively considerable carbapenem resistance among isolates. This is the first report about the presence of OXA-10 and OXA-48-producing Enterobacter spp. in Iran, indicating that the prevalence of oxacillinases in the country might be on the rise.