Silva J, Gatica R, Aguilar C, Becerra Z, Garza-Ramos U, Velázquez M, Miranda G, Leaños B, Solórzano F, Echániz G
Department of Bacterial Resistance, National Institute of Public Health, Center for Research on Infectious Diseases, Cuernavaca, Morelos, Mexico.
J Clin Microbiol. 2001 Sep;39(9):3193-6. doi: 10.1128/JCM.39.9.3193-3196.2001.
Thirty-one strains of Klebsiella pneumoniae (including 10 duplicates) from 21 septicemic pediatric patients (age, <2 months) were studied during a 4-month period (June to October 1996) in which the fatality rate was 62% (13 of 21). These isolates identified by the API 20E system yielded the same biotype. Pulsed-field gel electrophoresis experiments revealed the same clone in 31 strains. The isolates were multidrug-resistant but were still susceptible to ciprofloxacin, imipenem, and cefoxitin. A 135-kb plasmid was harbored in all of the isolates. No transconjugants were obtained that were resistant to ampicillin, cefotaxime, tetracycline, or gentamicin. Isoelectric focusing for beta-lactamases was performed on all strains, and three bands with pIs of 5.4, 7.6, and 8.2 were obtained. Of these, the pI 8.2 beta-lactamase had an extended-spectrum beta-lactamase phenotype. PCR amplification of both TEM- and SHV-type genes was obtained. The sequence analysis of the SHV PCR product indicated a mutation corresponding to the SHV-5 beta-lactamase.
在1996年6月至10月的4个月期间，对来自21名（年龄小于2个月）患败血症儿科患者的31株肺炎克雷伯菌（包括10株重复菌株）进行了研究，在此期间病死率为62%（21例中的13例）。通过API 20E系统鉴定的这些分离株具有相同的生物型。脉冲场凝胶电泳实验显示31株菌株为同一克隆。这些分离株对多种药物耐药，但对环丙沙星、亚胺培南和头孢西丁仍敏感。所有分离株都携带一个135 kb的质粒。未获得对氨苄西林、头孢噻肟、四环素或庆大霉素耐药的接合子。对所有菌株进行了β-内酰胺酶的等电聚焦分析，获得了3条等电点分别为5.4、7.6和8.2的条带。其中，等电点为8.2的β-内酰胺酶具有超广谱β-内酰胺酶表型。获得了TEM型和SHV型基因的PCR扩增产物。SHV PCR产物的序列分析表明存在一个与SHV-5β-内酰胺酶相对应的突变。
