TABLE 4.

Results for isolates not identified by AES as ESBL producers, for which PCR did not amplify an ESBL gene^a

Bacteriumb	Reference antibiotic(s)c	Interpretation of VITEK AES	Ceftriaxone hydrolysis inhibited by clavulanated	pI
E. aerogenes*	CTX, CAZ, FEP	Wild (cephalosporinase)	+	8.0
E. cloacae*	CTX, CAZ	High-level cephalosporinase	+	7.6
E. cloacae	CTX, CAZ	High-level cephalosporinase + impermeability	+	7.8, 8.2
E. cloacae*	CTX, CAZ	High-level cephalosporinase	+	5.4
E. cloacae*	CTX	High-level cephalosporinase	+	7.8, 8.2, 8.8
E. cloacae	CTX, CAZ	High-level cephalosporinase	+	5.4
E. cloacae*	CTX, CAZ	High-level cephalosporinase	+	8.8
E. cloacae*	CTX	High-level cephalosporinase	+	7.8
E. aerogenes*	CTX, CAZ	High-level cephalosporinase	+	8.2

^aA total of nine isolates (one from blood and eight from other sites) were tested. The results given are for individual isolates.

^b*, reported by AES as susceptible to at least one cephalosporin.

^cCTX, cefotaxime; CAZ, ceftazidime; FEP, cefepime.

^d+, hydrolysis and inhibition occur.