MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria
MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria
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DOI：
10.1128/aac.00615-15
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发表时间：
2015-10-01
影响因子：
4.9
通讯作者：
Rolain, Jean-Marc
中科院分区：
文献类型：
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作者：
Khennouchi, Nour Chems el Houda;Loucif, Lotfi;Rolain, Jean-Marc
阴沟肠杆菌是引起医院感染和暴发的重要病原菌之一。在这项研究中，收集了77株肠杆菌：27株来自阿尔及利亚医院(康斯坦丁、阿纳巴和斯基达)，50株来自法国马赛。采用基质辅助激光解吸电离飞行时间质谱仪(MALDI-TOF MS)对所有菌株进行鉴定。药敏试验采用纸片扩散法。用聚合酶链式反应检测产超广谱β-内酰胺酶(ESBL)、氟喹诺酮类耐药基因和氨基糖苷类修饰酶(AME)基因。流行病学分型采用MALDI-TOF MS和数据挖掘方法，以及多位点序列分型(MLST)。68株(阿尔及利亚27株，马赛41株)经MALDI-TOF MS鉴定为阴沟肠杆菌。阿尔及利亚分离株对抗生素的耐药率明显高于马赛分离株，尤其对β-内酰胺类和氨基糖苷类抗生素的耐药率较高。27株阿尔及利亚分离株中有18株和41株马赛分离株中有11株至少含有一个ESBL编码基因：Bla(CTX-M)和/或bla(Tm)。在27株阿尔及利亚分离株中的20株和41株马赛分离株中的8株[ant(2‘’)-Ia、aac(6‘)-Ib-cr、aadA1、aadA2和Arma]中检测到AME基因。接合实验表明，ARMA是以可转移质粒形式存在的。根据地理分布和物种水平，MALDI-TOF分型显示出三个独立的聚类群。基于MLST的系统发育树显示，在MALDI-TOF树状图中，来自一个泌尿外科单位的14个阴沟肠杆菌分离株聚集在一起，表明该单位发生了暴发。总之，MALDI-TOF对生物型菌株的能力得到了证实，应该实施监测措施，特别是对在法国住院的阿尔及利亚患者。
Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: bla(CTX-M) and/or bla(TEM). AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2 '')-Ia, aac(6 ')-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France.