TABLE 1.

Identification of the β-lactamases produced by the K. pneumoniae isolate

pIa	Inhibition by:b		Hydrolysis of cefotaxime overlay on IEFc	PCR-positive resulte	Likely enzyme based on pI, inhibitor profile, and PCR
	Clavulanate	Cloxacillin
8.2	Yes	No	Yes	SHV	SHV-12-like
8.0	Yes	No	No	ND	ND
7.6	Yes	No	No	SHV	SHV-1-like
7.2	No	Yes	Yes	FOX	FOX-like
6.9	Slightly	No	NDd	OXA	OXA-9f
6.7	Slightly	No	Yesd	KPC	KPC-like
5.7+	Yes	No	No	ND	ND
5.7	Slightly	No	No	PSE	PSE-1-like
5.4	Yes	No	No	TEM	TEM-1-like
5.25	Slightly	No	No	TEM	TEM-30-like

^apI values obtained by IEF. The + indicates that the pI values were in the same range but that the unidentified band was slightly more alkaline than the 5.7 band representing PSE-1.

^bInhibitor profiles on the IEF gel, in the absence or presence of 1 mM clavulanate or cloxacillin.

^cCefotaxime (CTX) hydrolysis was determined on the IEF gel using 0.75 μg/ml of CTX in an agar overlay combined with Escherichia coli ATCC 25922, with growth of the organism as an indicator of hydrolysis. ND, not determined.

^dDetermining the contribution of the CTX hydrolysis from each enzyme observed on the gel was difficult. Previous reports have indicated that OXA-9 does not hydrolyze CTX; therefore, the CTX hydrolysis observed was most likely due to the KPC enzyme.

^ePCR-positive results with family-specific primers.

^fDetermined by partial sequence analysis.