The present study aimed to evaluate TEM-1 or -2 and SHV-1 β-lactamases frequency in multidrug-resistant (MDR) Enterobacteriaceae isolated from patients’ urine in northern Iran. The resistance pattern to 20 antibiotics and ESBL production in 200 MDR Enterobacteriaceae was detected using the disk diffusion test and double-disk synergy test (DDST), respectively. Multiplex PCR was applied to detect bla_{TEM-1 or -2} and bla_SHV genes in isolates. DDST findings were inconsistent with multiplex PCR results. The distribution of each of bla_{TEM-1 or -2} and bla_SHV genes, either alone or in combination, in the ESBL-producing isolates was higher than the non-ESBL-producing isolates. There was a significant effect of the presence of bla_{TEM-1 or -2} gene on resistance to cephalotin at the p < 0.01 level and cefepime, tetracycline, and streptomycin at the P < 0.05 level, and the presence of bla_SHV-1 gene on resistance to fosfomycin at the P < 0.05 level as well as the presence both bla_{TEM-1 or -2} and bla_SHV-1 genes on resistance to cephalotin and fosfomycin at the P < 0.01 level. In all isolates, ESBL production, except for cephalotin resistance, did not improve resistance to other antibiotics used and even non-ESBL-producing isolates showed higher resistance to antibiotics compared to ESBL-producing isolates. It seems that mechanisms other than production of ESBL to be involved as part of the resistance mechanisms of the studied isolates against the used antibiotics. For epidemiological studies, both phenotypic and molecular tests must be included to identify the bla_{TEM-1 or -2} and bla_SHV-1 genotypes to ensure infection prevention and control.

本研究旨在评估从伊朗北部患者尿液中分离出的耐多药 (MDR)肠杆菌科细菌中 TEM-1 或 -2 和 SHV-1 β-内酰胺酶的频率。分别使用盘扩散试验和双盘协同试验 (DDST) 检测了 200 种 MDR肠杆菌科对 20 种抗生素和 ESBL 产生的耐药模式。多重 PCR 用于检测分离物中的bla _{TEM-1 或 -2}和bla _SHV基因。DDST 结果与多重 PCR 结果不一致。bla _{TEM-1 或 -2}和bla _SHV的分布产生 ESBL 的分离株中单独或组合的基因高于非产生 ESBL 的分离株。bla _TEM-1或-2基因的存在对头孢菌素的耐药性有显着影响，p  < 0.01水平，头孢吡肟、四环素和链霉素耐药性的p  < 0.05水平，bla _SHV-1基因的存在对磷霉素的耐药性在P  < 0.05 水平以及bla _{TEM-1 或 -2}和bla _SHV-1基因对头孢菌素和磷霉素的耐药性在P < 0.01 水平。在所有分离株中，除了头孢菌素耐药性外，ESBL 的产生并没有提高对所用其他抗生素的耐药性，甚至与产生 ESBL 的分离株相比，即使不产生 ESBL 的分离株也表现出更高的抗生素耐药性。似乎除了产生 ESBL 之外的机制也参与了所研究的分离株对所用抗生素的耐药机制的一部分。对于流行病学研究，必须包括表型和分子检测，以确定bla _{TEM-1 或 -2}和bla _SHV-1基因型，以确保预防和控制感染。