Rachdi M, Boutiba-Ben Boubaker I, Moalla S, Smaoui H, Hammami A, Kechrid A, Ben Redjeb S
Laboratoire de recherche résistance aux antibiotiques, faculté de médecine de Tunis, Tunisia.
Pathol Biol (Paris). 2008 May;56(3):125-9. doi: 10.1016/j.patbio.2007.05.005. Epub 2007 Jun 28.
One hundred of non duplicate Streptococcus pneumoniae resistant to erythromycin collected from three teaching hospitals in Tunisia from January 1998 to December 2004 were investigated to evaluate determine their resistance level to different macrolides and the mechanisms involved. Most erythromycin resistant S. pneumoniae were isolated from respiratory tract (34%). Eighty-three percent showed constitutive MLS(B) phenotype with high MICs of macrolides and lincosamides (MIC90 >256 microg/ml), 12% M phenotype with moderately increased MICs of macrolides (MIC90: 12 microg/ml) and low MICs of lincosamides (MIC90=0.75 microg/ml) and 5% inducible MLS(B) with high MICs of macrolides (MIC90 >256 microg/ml) and moderately increased MICs of lincosamides (MIC90=8 microg/ml). All strains were susceptible to quinupristun-dafopristin association and linezolid (MIC90=1 microg/ml). Strains belonging to MLS(B) phenotype were PCR positive for the erm B gene (88%). Twelve percent categorized as M phenotype carried the mef A gene. The rates of associated resistance were 68% to penicillin G, 53% to tetracyclines, 61% to cotrimoxazole, 21% to chloramphenicol and 13% to ciprofloxacin. MLS(B) constitutive phenotype conferring cross resistance to macrolides, lincosamides and streptogramins B with high level of resistance was the most prevalent. Thus, quinupristin-dalfopristin association and linezolid remain the most active molecules.
1998年1月至2004年12月期间，从突尼斯的三家教学医院收集了100株对红霉素耐药的非重复肺炎链球菌，以评估其对不同大环内酯类药物的耐药水平及相关机制。大多数对红霉素耐药的肺炎链球菌分离自呼吸道（34%）。83%表现为组成型MLS(B)表型，对大环内酯类和林可酰胺类药物的最低抑菌浓度（MIC）较高（MIC90>256μg/ml）；12%为M表型，大环内酯类药物的MIC中度升高（MIC90：12μg/ml），林可酰胺类药物的MIC较低（MIC90=0.75μg/ml）；5%为诱导型MLS(B)，大环内酯类药物的MIC较高（MIC90>256μg/ml），林可酰胺类药物的MIC中度升高（MIC90=8μg/ml）。所有菌株对奎奴普丁-达福普汀合剂和利奈唑胺敏感（MIC90=1μg/ml）。属于MLS(B)表型的菌株erm B基因PCR检测呈阳性（88%）。归类为M表型的菌株中有12%携带mef A基因。对青霉素G的联合耐药率为68%，对四环素为53%，对复方新诺明为61%，对氯霉素为21%，对环丙沙星为13%。赋予对大环内酯类、林可酰胺类和链阳菌素B高水平交叉耐药的组成型MLS(B)表型最为常见。因此，奎奴普丁-达福普汀合剂和利奈唑胺仍然是最有效的药物。
