Aim:  To compare the performance of a new chromogenic agar medium CHROMagar ESBL (KC‐ESBL) to chromID ESBL (SB‐ESBL) for the detection and presumptive identification of extended‐spectrum β‐lactamase (ESBL)‐producing Enterobacteriaceae directly from clinical specimens. Methods and Results:  A total of 256 specimens were screened for ESBL producers. Also, the genotypes of the ESBLs and plasmid‐mediated AmpC β‐lactamases (pAmpCBLs) were characterized by PCR and sequencing. Among the 256 specimens, 17 (6·6%) ESBL producers were isolated on both media. The sensitivity, specificity, positive predictive value and negative predictive value were higher for KC‐ESBL (100, 93·3, 51·5 and 100%, respectively) than for SB‐ESBL (88·2, 92·9, 46·9 and 99·1%, respectively) (P = 0·72). Enterobacteriaceae harbouring pAmpCBL genes as well as chromosomal cephalosporinase‐ and penicillinase‐hyperproducing Enterobacteriaceae and Pseudomonas aeruginosa accounted for the false‐positive results. Conclusion:  KC‐ESBL can detect ESBL producers from clinical specimens with good selectivity and rapid presumptive identification by means of colony colour at 24 h. Significance and Impact of the Study:  This is the first study that has evaluated the performance of KC‐ESBL that enables the detection and presumptive identification of ESBL producers from clinical specimens.

dWe investigated a novel Japanese isolate of sequence type 11 (ST11), the Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing K. pneumoniae strain Kp3018, which was previously obtained from a patient treated at a Brazilian hospital. This strain was resistant to various antibiotic classes, including carbapenems, and harbored the gene bla KPC-2 , which was present on the transferable plasmid of ca. 190 kb, in addition to the bla CTX-M-15 gene. Furthermore, the ca. 2.3-kb sequences (ISKpn8-bla KPC-2 -ISKpn6-like), encompassing bla KPC-2 , were found to be similar to those of K. pneumoniae strains from China.

No abstract

We examined the molecular characteristics of 13 phenotypically confirmed carbapenemasepositive Enterobacteriaceae clinical isolates, including the relationships between plasmidmediated quinolone-resistance genes (qnr), 69-N-aminoglycoside acetyltransferase-encoding genes [aac(69)] and AmpC-encoding genes (pAmpC). Twelve isolates were bla IMP-1 positive (92.3 %), while one was bla IMP-11 positive (7.7 %). We detected qnr, aac(69) and pAmpC genes designated bla ACT-1 -like in 76.9 %, 100 % and 53.8 %, respectively, of the 13 isolates. Plasmids were transferred successfully for three of the 13 metallo-b-lactamase (MBL)-producing isolates, and the sizes of plasmids extracted from these donors and transconjugants were deduced to be 65 kb or 70 kb. OmpC or OmpF protein expression was reduced in all Enterobacter cloacae, and one Klebsiella oxytoca lacked OmpK36. We demonstrate what appears to be the first evidence that, in Japan, Enterobacteriaceae producing MBLs carry various plasmid-mediated resistance genes, which may cause a further decrease in carbapenem susceptibility through reduction of the expression of outer-membrane proteins.