Department of Microbiology, Islamic Azad University, Lahijan Branch, Iran.
Department of Microbiology, Zanjan University of Medical Sciences, Zanjan, Iran.
Arab J Gastroenterol. 2022 May;23(2):102-107. doi: 10.1016/j.ajg.2022.02.003. Epub 2022 Apr 23.
Extraintestinal pathogenic Escherichia coli (ExPEC) is one of the most common bacterial pathogens, which causes a remarkable amount of morbidity and mortality. This study was designed to determine the antibiotic resistance profiles, phylogenetic groups, and subgroup analyses among the ExPEC strains isolated from hospitalized patients in north Iran.
This cross-sectional investigation was conducted at five educational hospitals in Rasht in north Iran. Using standard microbiological tests, 150 E. coli isolates were identified. The antibiotic susceptibility pattern of all isolates was determined using the disk diffusion method. The double disk phenotypic confirmatory test was performed to detect extended-spectrum β-lactamase (ESBL)-producing isolates. A triplex polymerase chain reaction (PCR) was performed to determine the phylogenetic group of each strain.
The results of antibiogram pattern showed that E. coli isolates were mostly non-susceptible to ampicillin (79.3%), followed by nalidixic acid (75.3%) and cephalothin (70%), whereas nitrofurantoin (94.7%) was the most effective agent, followed by imipenem (92.7%). The rate of ESBL-producing isolates was 53.3% (80/150). Multiplex PCR screening revealed that the most common phylogroup was the B2 group (97 isolates; 64.6%), followed by the D group (34, 22.7%). In contrast, phylogroup analyses showed that B2 (50.7%) and D (16.4%) were the most common subgroups.
Our findings indicated a considerable rate of antibiotic resistance and ESBL-producing isolates among E. coli strains isolated from clinical samples. Moreover, we reported a tendency that most isolates belonged to the B2 and D phylogroups. As a result, the detection of genotypic identical or similar isolates indicated that these isolates have an endurance capability in the hospital environment and could be transmitted among patients.
肠外致病性大肠杆菌（ExPEC）是最常见的细菌病原体之一，可导致大量发病率和死亡率。本研究旨在确定分离自伊朗北部住院患者的 ExPEC 菌株的抗生素耐药谱、系统发育群和亚群分析。
这是在伊朗北部拉什特的五所教学医院进行的一项横断面研究。使用标准微生物学检测方法，鉴定了 150 株大肠杆菌分离株。采用纸片扩散法测定所有分离株的抗生素药敏模式。进行双纸片表型确证试验以检测产超广谱β-内酰胺酶（ESBL）的分离株。采用三重聚合酶链反应（PCR）检测各菌株的系统发育群。
药敏谱结果显示，大肠杆菌分离株对氨苄西林（79.3%）的耐药性最高，其次是萘啶酸（75.3%）和头孢噻吩（70%），而呋喃妥因（94.7%）是最有效的药物，其次是亚胺培南（92.7%）。产 ESBL 分离株的检出率为 53.3%（80/150）。多重 PCR 筛查显示最常见的系统发育群是 B2 群（97 株；64.6%），其次是 D 群（34 株；22.7%）。相比之下，系统发育群分析显示 B2（50.7%）和 D（16.4%）是最常见的亚群。
我们的研究结果表明，从临床样本中分离出的大肠杆菌菌株中存在相当高的抗生素耐药率和产 ESBL 分离株。此外，我们发现大多数分离株属于 B2 和 D 系统发育群。因此，检测基因型相同或相似的分离株表明，这些分离株在医院环境中具有生存能力，并可能在患者之间传播。
