Abstract：
OBJECTIVE: Carbapenem-resistant Acinetobacter baumannii (CR-Ab) is an important cause of infections in burn patients. This study aimed to characterize the antimicrobial susceptibility pattern of CR-Ab isolated from burns in Burn Intensive Care Unit (BICU) of the Trauma and Burn Centre of Ben Arous, to determine the prevalence of β-lactamase-encoding genes and to search eventual genetic relatedness of CR-Ab strains.
RESULTS: From 15 December 2016 to 2 April 2017, all nonduplicated CR-Ab isolated in burn patients in the BICU were screened by simplex Polymerase Chain Reaction (PCR) for the class A, B, C, and D β-lactamase genes. Sequencing was performed for NDM gene only. Genetic relatedness was determined by using pulsed field gel electrophoresis (PFGE) and by multilocus sequence typing. During the study period, 34 strains of CR-Ab were isolated in burns, mainly in blood culture (n = 14) and central vascular catheter (n = 10). CR-Ab strains were susceptible to colistin but resistant to amikacin (91%), ciprofloxacin (100%), rifampicin (97%), and trimethoprim-sulfamethoxazole (100%). All strains harbored blaOXA-51-like and blaOXA-23 genes, only or associated to blaGES (n = 26; 76%), blaADC (n = 20; 59%), blaPER-1 (n = 6; 18%) or/and blaNDM-1 (n = 3; 9%). PFGE identified 16 different clusters and revealed that most strains belonged to one major cluster A (n = 15; 44.1%). Among NDM-1 isolates, two were clonally related in PFGE and belonged to two single locus variant sequence type ST-6 and ST-85.
CONCLUSIONS: This is the first description of clonally related NDM-1 and OXA-23-producing A. baumannii strains in the largest Tunisian BICU associated with two single locus variant sequence types ST6 and ST85.
RESULTS: From 15 December 2016 to 2 April 2017, all nonduplicated CR-Ab isolated in burn patients in the BICU were screened by simplex Polymerase Chain Reaction (PCR) for the class A, B, C, and D β-lactamase genes. Sequencing was performed for NDM gene only. Genetic relatedness was determined by using pulsed field gel electrophoresis (PFGE) and by multilocus sequence typing. During the study period, 34 strains of CR-Ab were isolated in burns, mainly in blood culture (n = 14) and central vascular catheter (n = 10). CR-Ab strains were susceptible to colistin but resistant to amikacin (91%), ciprofloxacin (100%), rifampicin (97%), and trimethoprim-sulfamethoxazole (100%). All strains harbored blaOXA-51-like and blaOXA-23 genes, only or associated to blaGES (n = 26; 76%), blaADC (n = 20; 59%), blaPER-1 (n = 6; 18%) or/and blaNDM-1 (n = 3; 9%). PFGE identified 16 different clusters and revealed that most strains belonged to one major cluster A (n = 15; 44.1%). Among NDM-1 isolates, two were clonally related in PFGE and belonged to two single locus variant sequence type ST-6 and ST-85.
CONCLUSIONS: This is the first description of clonally related NDM-1 and OXA-23-producing A. baumannii strains in the largest Tunisian BICU associated with two single locus variant sequence types ST6 and ST85.
摘要：
目的：耐碳青霉烯类鲍曼不动杆菌(CR-Ab)是烧伤患者感染的重要原因。这项研究旨在表征本·罗斯创伤和烧伤中心烧伤重症监护病房（BICU）烧伤中分离出的CR-Ab的抗菌敏感性模式，确定β-内酰胺酶编码基因的流行率，并搜索CR-Ab菌株的最终遗传相关性。
结果：从2016年12月15日至2017年4月2日，通过单纯聚合酶链反应（PCR）对BICU烧伤患者中分离出的所有非重复CR-Ab进行了A类筛查。B,C,和Dβ-内酰胺酶基因。仅对NDM基因进行测序。通过使用脉冲场凝胶电泳（PFGE）和多位点序列分型来确定遗传相关性。在学习期间,在烧伤中分离出34株CR-Ab，主要在血培养（n=14）和中心血管导管（n=10）。CR-Ab菌株对粘菌素敏感，但对阿米卡星耐药（91％），环丙沙星（100%），利福平（97%），和甲氧苄啶-磺胺甲恶唑(100%)。所有菌株都含有blaOXA-51-like和blaOXA-23基因，仅与火灾相关(n=26；76%)，blaADC（n=20；59%），blaPER-1(n=6;18%)或/和blaNDM-1(n=3;9%)。PFGE鉴定出16个不同的簇，并显示大多数菌株属于一个主要簇A（n=15；44.1％）。在NDM-1分离株中，两个在PFGE中克隆相关，属于两个单基因座变异序列类型ST-6和ST-85。
结论：这是最大的突尼斯BICU中克隆相关的NDM-1和OXA-23生产鲍曼不动杆菌菌株的首次描述，该菌株与两种单基因座变异序列类型ST6和ST85相关。
结果：从2016年12月15日至2017年4月2日，通过单纯聚合酶链反应（PCR）对BICU烧伤患者中分离出的所有非重复CR-Ab进行了A类筛查。B,C,和Dβ-内酰胺酶基因。仅对NDM基因进行测序。通过使用脉冲场凝胶电泳（PFGE）和多位点序列分型来确定遗传相关性。在学习期间,在烧伤中分离出34株CR-Ab，主要在血培养（n=14）和中心血管导管（n=10）。CR-Ab菌株对粘菌素敏感，但对阿米卡星耐药（91％），环丙沙星（100%），利福平（97%），和甲氧苄啶-磺胺甲恶唑(100%)。所有菌株都含有blaOXA-51-like和blaOXA-23基因，仅与火灾相关(n=26；76%)，blaADC（n=20；59%），blaPER-1(n=6;18%)或/和blaNDM-1(n=3;9%)。PFGE鉴定出16个不同的簇，并显示大多数菌株属于一个主要簇A（n=15；44.1％）。在NDM-1分离株中，两个在PFGE中克隆相关，属于两个单基因座变异序列类型ST-6和ST-85。
结论：这是最大的突尼斯BICU中克隆相关的NDM-1和OXA-23生产鲍曼不动杆菌菌株的首次描述，该菌株与两种单基因座变异序列类型ST6和ST85相关。
