Makanera Abdoulaye, Arlet Guillaume, Gautier Valérie, Manai Mohamed
Laboratoire de Biochimie et Biologie Moléculaire, Faculté des Sciences de Tunis, Département de Biologie, Université de Tunis El Manar, 2092 Tunis, Tunisia.
J Clin Microbiol. 2003 Jul;41(7):2940-5. doi: 10.1128/JCM.41.7.2940-2945.2003.
We studied 31 clinical isolates of Salmonella enterica serotype Mbandaka resistant to broad-spectrum cephalosporins and recovered in Tunisia over a 5-year period. The transferability of this resistance was demonstrated by conjugation experiments. Thirty of the 31 isolates were positive in the double-disk synergy test. By isoelectric focusing analysis, all of the isolates were found to produce a band of beta-lactamase activity with a pI of 5.9. Three of these isolates produced an additional band with a pI of 7.6. PCR and DNA sequencing identified these beta-lactamases as TEM-4 and SHV-2a, respectively. The remaining isolate, highly resistant to ceftazidime but susceptible to cefepime, produced a beta-lactamase that focused at pI 7.8. No synergy was detected by the double-disk synergy test. Sequence analysis of the bla gene amplified by PCR showed that the plasmid-mediated AmpC-type enzyme was ACC-1a. Fingerprinting analysis by repetitive-element PCR and enterobacterial repeat intergenic consensus-PCR suggested that 29 of the 31 Salmonella serotype Mbandaka isolates belonged to the same clonal population.
我们研究了31株肠炎沙门氏菌Mbandaka血清型临床分离株,这些菌株对广谱头孢菌素耐药,是在突尼斯5年期间分离得到的。通过接合试验证明了这种耐药性的可转移性。31株分离株中有30株在双纸片协同试验中呈阳性。通过等电聚焦分析,发现所有分离株均产生一条pI为5.9的β-内酰胺酶活性带。其中3株分离株还产生了一条pI为7.6的带。PCR和DNA测序分别将这些β-内酰胺酶鉴定为TEM-4和SHV-2a。其余一株对头孢他啶高度耐药但对头孢吡肟敏感,产生一条聚焦于pI 7.8的β-内酰胺酶。双纸片协同试验未检测到协同作用。PCR扩增的bla基因序列分析表明,该质粒介导的AmpC型酶为ACC-1a。通过重复元件PCR和肠杆菌重复基因间共有序列PCR进行指纹分析表明,31株沙门氏菌Mbandaka血清型分离株中有29株属于同一克隆群体。