Hama-Soor Taib Ahmed, Salih Sabiha Sharif, Muhamad Shno Jalal
Medical Laboratory Department, Technical College of Health, Sulaimani Polytechnic University, Sulaimani, Iraq.
Bacteriology Department, Central Laboratory, Sulaimani Teaching Hospital, Sulaimani, Iraq.
Ann Parasitol. 2021;67(4):659-670. doi: 10.17420/ap6704.382.
Escherichia coli bearing β-lactamase resistance genes are a leading cause of developing multi-drug resistance. The aim of this work was to study the molecular characterization and genotypic pattern of β-lactamase resistance genes in Escherichia coli. In total, 203 urine samples of patients who have symptoms of urinary tract infections (UTI) were screened to isolate E. coli and characterize resistance genes. Out of 203 patients, 32 (15.7%) cases were infected with E. coli. All E. coli samples showed a complete resistance against many antibiotics, including tetracycline (100%), rifampin (100%), and gentamycin (100%), but recorded the lowest resistance rate against imipenem (12.5%). Based on the existence of one or more gene of the chuA, yjaA and DNA fragment TSPE4.C2, E. coli is classified under three phylogenetic groups, A, B1, B2, and D. The highest rate of pathogenic E. coli was characterized under phylogenetic groups B2 (37.5%), and D (34.3%). Fifty β-lactamase resistance genes were recovered in this study and some isolates harbored more than one resistance genes. Among them, blaCTX recorded the highest rate, 27 (84.3%), while none of the isolates was detected to bear blaSHV resistance gene. Among five blaCMY genes, three different variants were revealed via sequencing and phylogenetic tree. Two mutations were found in one isolate at position 65 and 566, and three mutations were detected in another isolate at position number 413, 574 and 584, in comparison to a wild type variant. In conclusion, it was revealed that 15.7% cases of urinary tract infections were caused by E. coli. E. coli isolates were completely resistant to many antibiotics, but they were more sensitive to imipenem. Among the fifty β-lactamase resistance genes recovered in this study, blaCTX was the most common gene. There were three variants among blaCMY genes in a single area of study.
携带β-内酰胺酶耐药基因的大肠杆菌是导致多重耐药的主要原因。本研究的目的是研究大肠杆菌中β-内酰胺酶耐药基因的分子特征和基因型模式。总共对203例有尿路感染（UTI）症状患者的尿液样本进行筛查，以分离大肠杆菌并鉴定耐药基因。在203例患者中，32例（15.7%）感染了大肠杆菌。所有大肠杆菌样本对多种抗生素均表现出完全耐药，包括四环素（100%）、利福平（100%）和庆大霉素（100%），但对亚胺培南的耐药率最低（12.5%）。基于chuA、yjaA和DNA片段TSPE4.C2中一个或多个基因的存在，大肠杆菌被分为A、B1、B2和D四个系统发育组。致病性大肠杆菌发生率最高的是B2组（37.5%）和D组（34.3%）。本研究共检测到50个β-内酰胺酶耐药基因，部分分离株携带不止一个耐药基因。其中，blaCTX的发生率最高，为27个（84.3%），而未检测到携带blaSHV耐药基因的分离株。在5个blaCMY基因中，通过测序和系统发育树揭示了3种不同变体。与野生型变体相比，在一个分离株的第65和566位发现了2个突变，在另一个分离株的第413、574和584位检测到3个突变。总之，研究发现15.7%的尿路感染病例由大肠杆菌引起。大肠杆菌分离株对多种抗生素完全耐药，但对亚胺培南更敏感。在本研究检测到的50个β-内酰胺酶耐药基因中，blaCTX是最常见的基因。在单个研究区域的blaCMY基因中有3种变体。
