Réglier-Poupet Hélène, Naas Thierry, Carrer Amélie, Cady Anne, Adam Jean-Marie, Fortineau Nicolas, Poyart Claire, Nordmann Patrice
Service de Bactériologie, Hôpital Cochin, Assistance Publique Hôpitaux de Paris, Faculté de Médecine Paris Descartes, 27 Rue du Faubourg Saint Jacques, 75014 Paris, France.
Service de Bactériologie-Virologie, INSERM U914: Emerging Resistance to Antibiotics, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris XI, 78 Rue du Général Leclerc, 94275 Le Kremlin-Bicêtre, France.
J Med Microbiol. 2008 Mar;57(Pt 3):310-315. doi: 10.1099/jmm.0.47625-0.
The chromogenic agar medium chromID ESBL (bioMérieux) was compared with BLSE agar medium (AES) for selective isolation and presumptive identification of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae from clinical samples. A total of 765 samples (468 rectal swabs, 255 urine samples and 42 pulmonary aspirations) obtained from 547 patients was processed. All bacterial strains isolated on either medium were further characterized using biochemical tests, and ESBL producers were confirmed by synergy testing. Genetic characterization of ESBL genes was determined by PCR. A total of 33 ESBL-producing Enterobacteriaceae strains [Escherichia coli (n=16), Klebsiella pneumoniae (n=8), Enterobacter spp. (n=3), Citrobacter spp. (n=5) and Proteus mirabilis (n=1)] was recovered. The sensitivity after 24 h incubation was 88 % for chromID ESBL and 85 % for BLSE agar. At 48 h, the sensitivity of chromID ESBL increased to 94 % and was higher than that obtained with BLSE agar. The positive predictive value at 24 h for chromID ESBL was 38.7 % [95 % confidence interval (95 % CI) 28.3 -50.2 %)], which was significantly higher than that for BLSE agar [15.4 %, 95 % CI 10.1 -21.5 %]. On both media, false-positive results were mostly due to Pseudomonas aeruginosa and to Enterobacteriaceae overproducing chromosomal cephalosporinase (Enterobacter spp.) or a chromosomal penicillinase (Klebsiella oxytoca). This study showed that chromID ESBL, a ready-to-use chromogenic selective medium, is sensitive and specific for rapid, presumptive identification of ESBL-producing Enterobacteriaceae. Its chromogenic properties and its selectivity are particularly useful in specimens containing resident associated flora.
将用于从临床样本中选择性分离和初步鉴定产超广谱β-内酰胺酶（ESBL）肠杆菌科细菌的显色琼脂培养基chromID ESBL（生物梅里埃公司）与BLSE琼脂培养基（AES公司）进行比较。对从547例患者获得的765份样本（468份直肠拭子、255份尿液样本和42份肺穿刺样本）进行处理。使用生化试验对在任何一种培养基上分离出的所有细菌菌株进行进一步鉴定，并通过协同试验确认产ESBL菌株。通过聚合酶链反应（PCR）确定ESBL基因的基因特征。共分离出33株产ESBL肠杆菌科细菌菌株[大肠埃希菌（n = 16）、肺炎克雷伯菌（n = 8）、肠杆菌属（n = 3）、柠檬酸杆菌属（n = 5）和奇异变形杆菌（n = 1）]。培养24小时后，chromID ESBL的敏感性为88%，BLSE琼脂为85%。在48小时时，chromID ESBL的敏感性增至94%，高于BLSE琼脂。chromID ESBL在24小时时的阳性预测值为38.7%[95%置信区间（95%CI）28.3 - 50.2%]，显著高于BLSE琼脂[15.4%，95%CI 10.1 - 21.5%]。在两种培养基上，假阳性结果主要归因于铜绿假单胞菌以及产染色体头孢菌素酶过量的肠杆菌科细菌（肠杆菌属）或染色体青霉素酶（产酸克雷伯菌）。本研究表明，chromID ESBL这种即用型显色选择性培养基对快速初步鉴定产ESBL肠杆菌科细菌具有敏感性和特异性。其显色特性和选择性在含有常驻相关菌群的标本中尤为有用。
