Molecular Detection of Carbapenemase Genes in Extensive Drug Resistant Acinetobacter baumannii Clinical Isolates from ICU Patients, Khartoum

Background: The emergence of carbapenemase producing Acinetobacter baumannii is increasingly reported nowadays and constitutes a major problem to the intensive care unit (ICU) patients with notable extensive-drug resistance ability. The study investigates carbapenemase producing A. baumannii strains exhibiting an extensively drug-resistant (XDR) phenotype, isolated from ICU patients in Khartoum. Methods: A total of 100 nonduplicate Gram-negative coccobacilli strains were obtained from microbiology laboratory of ICU patients’ clinical isolates. Molecular identification of A. baumannii was performed by targeting 16S rRNA gene using specifically designed primers. Then, XDR strains were determined by susceptibility testing (disc diffusion). For detection of carbapenemase genes Polymerase chain reaction (PCR) was carried out. Result: Of 100 ICU clinical isolates, 38 (38.0%) was confirmed A. baumannii strains, those strains showed 100% carbapenem resistance and 60.5% extensive drug resistance to the antibiotics tested. The frequency of carbapenemase producer was 57.9% (22/38) of carbapenem resistance A. baumannii (CRAB). The most common carbapenemase associated with resistance was blaOXA gene followed by blaNDM and blaGES A. baumannii isolates. The co-occurrence of blaOXA-48-like and blaNDM, blaOXA-23-like and blaOXA-51, and blaNDM-1 and blaOXA-51 was detected in 22.7%, 18.2% strains and 4.5% respectively. A unique characteristic of our findings was the coharbouring of the genes blaNDM-1, blaOXA-23-like, blaOXA-51 and blaOXA-143 in 9.1% strains (2/22), and this was the first report in the Khartoum city, Sudan. Conclusion: We have demonstrated for the first time a high prevalence of XDR-carbapenemase producing A. baumannii clinical isolates from ICU patients in Khartoum. Also an emergent blaOXA-143 was reported as High-Risk Clones. This highlights the routine mentoring of XDR-carbapenemase producing A. baumannii to avoid clone dissemination in our region hospitals.

某教学医院2011-2021年血培养常见耐药菌临床分布及其药敏结果分析

目的 研究该院近11年血培养分离的多重耐药菌(MDROS)的临床分布情况及其对常用抗菌药物的耐药性,旨在为院内防控及抗感染方案的选择提供指导。方法 收集2011年1月至2021年12月该院的住院患者血流感染临床送检标本分离菌株的临床资料,采用法国梅里埃公司的VITEK2 Compact全自动细菌鉴定和药敏系统对MDROS的临床分布特点及其交叉耐药情况进行统计分析。结果 (1)该院住院患者所送检血清标本中,共检出非重复病原菌14 918株,MDROS 4 081株,占27.4%。检出的病原菌排前5位的分别是大肠埃希菌(占21.4%)、鲍曼不动杆菌(占14.1%)、肺炎克雷伯菌(占8.9%)、金黄色葡萄球菌(占7.4%)和铜绿假单胞菌(占6.1%)。(2)药敏结果提示:超广谱β-内酰胺酶的大肠埃希菌(ESBL)对亚胺培南、厄他培南、阿米卡星敏感,耐药率在2011-2021年均<5.0%;对头孢呋辛、氨曲南、美罗培南的耐药率呈现逐年升高趋势;(3)泛耐药鲍曼不动杆菌(PDR-AB)耐药率最高,对头孢类抗菌药物的耐药率由2011年的70.0%~80.0%升高为2021年全耐药(100.0%);对米诺环素的耐药率由12.5%升高至30.5%,对替加环素较为敏感,耐药率为0.1%;(4)耐碳青酶烯类铜绿假单胞菌(CR-PAE)对替加环素、呋喃妥因、亚胺培南的耐药率由2011年的88.0%、78.0%、92.3%逐年升高到100.0%;(5)耐甲氧西林金黄色葡萄球菌(MRSA)对大环内酯类、头孢类、青霉素类抗菌药物的耐药率均在80.0%以上,年份间无明显变化趋势;对环丙沙星的耐药率由88.2%逐年降低至62.2%,对万古霉素、利奈唑胺敏感,未发现耐药菌株;(6)耐碳青酶烯类肺炎克雷伯菌(CR-KPN)对氨曲南、甲氧苄啶/复方磺胺甲噁唑、黏菌素的耐药率由77.2%、49.1%、4.0%升高至97.0%、83.9%、12.8%;对阿米卡星、左氧氟沙星的耐药率呈现逐年降低趋势。结论 由于严峻的细菌耐药形势及抗菌药物的广泛使用,使得该院MDROS检出率较高,耐药情况严重。因此,应制订并落实有效的MDROS防控措施,加强临床对MDROS感染的持续监控,以防止耐药菌株的播散。