Background The global spread of carbapenemase-producing Enterobacteriaceae represents a public health concern. The aim of this study was to investigate prevalence of carbapenem resistance, oxacillinase types and the presence of class 1–3 integrons among Enterobacter clinical isolates from an Iranian inpatients' population. Methods Ninety Enterobacter isolates recovered from hospitalized patients were diagnosed by the standard microbiological methods. Antibiogram pattern was also determined. The

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... presence of class 1–3 integrons and four types of oxacillinase genes were assessed using PCR. Results Of the 90 Enterobacter isolates, the most common species was identified as E. aerogenes, (45.6%), followed by E. cloacae (30%). The highest resistance rate was against to 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%). Conclusion The determinants of class 1 integron with OXA-10 and OXA-48 like carbapememases have been responsible of relatively considerable of carbapenem resistance among isolates. This is the first OXA-10 and OXA-48-producing Enterobacter spp. in Iran, indicating that the prevalence of oxacillinases might be on the rise in country.