Chair of Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, Marchioninistr. 17, 81377, Munich, Germany.
Institute of Health Sciences, Jimma University, Jimma, Ethiopia.
BMC Infect Dis. 2018 Oct 20;18(1):524. doi: 10.1186/s12879-018-3436-7.
The prevalence of extended-spectrum β-lactamases (ESBLs) have been reported in clinical isolates obtained from various hospitals in Ethiopia. However, there is no data on the prevalence and antibiotic susceptibility patterns of CTX-M type ESBL produced by Gram-negative bacilli. The aim of this study was to determine the frequency and distribution of the bla genes and the susceptibility patterns in ESBL producing clinical isolates of Gram-negative bacilli in Jimma University Specialized Hospital (JUSH), southwest Ethiopia.
A total of 224 non-duplicate and pure isolates obtained from clinically apparent infections, were included in the study. Identification of the isolates was performed by MALDI-TOF mass spectrometry. Susceptibility testing and ESBL detection was performed using VITEK® 2, according to EUCAST v4.0 guidelines. Genotypic analysis was performed using Check-MDR CT103 Microarrays.
Of the total 112 (50.0%) isolates screen positive for ESBLs, 63.4% (71/112) tested positive for ESBL encoding genes by Check-MDR array, which corresponds to 91.8% (67/73) of the total Enterobacteriaceae and 10.3% (4/39) of nonfermenting Gram-negative bacilli. Among the total ESBL gene positive isolates, 95.8% (68/71) carried bla genes with CTX-M group 1 type15 being predominant (66/68; 97.1% of CTX-M genes). The bla carrying Enterobacteriaceae (n = 64) isolates showed no resistance against imipenem and meropenem and a moderate resistance rate against tigecycline (14.1%), fosfomycin (10.9%) and amikacin (1.6%) suggesting the effectiveness of these antibiotics against most isolates. On the other hand, all the bla positive Enterobacteriaceae showed a multidrug resistant (MDR) phenotype with remarkable co-resistances (non-susceptibility rates) to aminoglycosides (92.2%), fluoroquinolones (78.1%) and trimethoprim/sulfamethoxazol (92.2%).
This study demonstrates a remarkably high prevalence of bla genes among ESBL-producing isolates. The high level of resistance to β-lactam and non-β-lactam antibiotics as well as the trend to a MDR profile associated with the bla genes are alarming and emphasize the need for routine diagnostic antimicrobial susceptibility testing for appropriate choice of antimicrobial therapy.
在埃塞俄比亚的多家医院获得的临床分离株中，已报告存在扩展谱β-内酰胺酶（ESBL）的流行情况。然而，尚无关于产 CTX-M 型 ESBL 的革兰氏阴性杆菌的流行情况和抗生素药敏模式的数据。本研究的目的是确定产 ESBL 的革兰氏阴性杆菌临床分离株中 bla 基因的频率和分布以及药敏模式，这些分离株来自埃塞俄比亚西南部的 Jimma 大学专科医院（JUSH）。
本研究共纳入 224 份来自临床明显感染的非重复和纯分离株。通过 MALDI-TOF 质谱法进行分离株鉴定。药敏试验和 ESBL 检测采用 VITEK®2 根据 EUCAST v4.0 指南进行。采用 Check-MDR CT103 微阵列进行基因分析。
在总共 112 份（50.0%）筛选出的 ESBL 阳性分离株中，63.4%（71/112）通过 Check-MDR 阵列检测到 ESBL 编码基因阳性，这相当于肠杆菌科的 91.8%（67/73）和非发酵革兰氏阴性杆菌的 10.3%（4/39）。在总 ESBL 基因阳性分离株中，95.8%（68/71）携带 bla 基因，其中 CTX-M 组 1 型 15 型最为常见（66/68；CTX-M 基因的 97.1%）。携带 bla 的肠杆菌科（n=64）分离株对亚胺培南和美罗培南无耐药性，对替加环素（14.1%）、磷霉素（10.9%）和阿米卡星（1.6%）的中度耐药率表明这些抗生素对大多数分离株有效。另一方面，所有 bla 阳性肠杆菌科均表现出多药耐药（MDR）表型，对氨基糖苷类（92.2%）、氟喹诺酮类（78.1%）和 trimethoprim/sulfamethoxazole（92.2%）的非敏感性率显著升高。
本研究表明产 ESBL 分离株中 bla 基因的流行率很高。β-内酰胺类和非β-内酰胺类抗生素的高度耐药性以及与 bla 基因相关的 MDR 趋势令人担忧，强调了进行常规诊断性抗菌药物敏感性试验以选择适当的抗菌药物治疗的必要性。
