title: Evaluation of MicroScan ESBL confirmation panel for Enterobacteriaceae-producing, extended-spectrum beta-lactamases isolated in Japan.
abstract: We assessed use of the MicroScan ESBL confirmation panel (Dade Behring, Tokyo, Japan) for the detection of eight Enterobacteriaceae-producing extended-spectrum beta-lactamases (ESBL) species. Of 137 bacterial strains isolated from patients in 32 hospitals in the Kinki area of Japan, 91 produced ESBL and comprised 60 bacteria (of E. coli, K. oxytoca, and K. pneumoniae) targeted by the NCCLS ESBL test and 31 non-target bacteria such as chromosomal AmpC-producing bacteria (e.g., Serratia marcescens, Enterobacter spp.). Sensitivity and specificity of the MicroScan panel for the target bacteria were 92% and 93%, respectively; sensitivity and specificity for non-target bacteria were 52% and 100%, respectively. There were 20 ESBL-positive strains that were not inhibited by clavulanic acid in the MicroScan panel (3 of 32 ESBL-producing E. coli strains, 1 of 24 K. pneumoniae, 1 of 4 K. oxytoca, 8 of 13 E. cloacae, and 7 of 14 S. marcescens), and most of them were bacteria not targeted by the NCCLS test. In 19 of the 20 strains, the synergy effect of clavulanic acid was observed in the modified-double-disk synergy test using only the cefepime-disk. Because these strains had high MICs of > or = 16 microg/ml for cephamycins such as cefoxitin and cefmetazole, these strains might produce high levels of AmpC in addition to ESBL. The MicroScan ESBL confirmation panel showed excellent performance in detecting target, but not other bacteria. Addition of cefepime and clavulanic acid to the MicroScan panel may significantly improve detection of non-target bacteria.
authors.affiliation: Division of Clinical Microbiology, Department of Clinical Pathology, Tenri Hospital, Nara, Japan. microbiology@tenriyorozu-hp.or.jp
authors.forename: Masaru
authors.initials: M
authors.lastname: Komatsu
authors.forename: Masanori
authors.initials: M
authors.lastname: Aihara
authors.forename: Kouichi
authors.initials: K
authors.lastname: Shimakawa
authors.forename: Mizuho
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nagasaka
authors.forename: Saori
authors.initials: S
authors.lastname: Fukuda
authors.forename: Shuji
authors.initials: S
authors.lastname: Matsuo
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Iwatani
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002442:Ceftazidime / Q000494:pharmacology; D004269:DNA, Bacterial / Q000032:analysis; D004755:Enterobacteriaceae / Q000145:classification* / Q000201:enzymology*; D006090:Gram-Negative Bacteria / Q000201:enzymology / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000201:enzymology / Q000302:isolation & purification; D006801:Humans; D007564:Japan; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction / Q000379:methods; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D002442:Ceftazidime; D001618:beta-Lactamases