TABLE 2.

Micronaut-S carbapenemase detection microplate results for 150 carbapenemase-negative Gram-negative isolates

Species	Total no.	No. of isolates demonstrating resistance mechanism(s)						No. of test resultsb
		ESBL	AmpC	ESBL + AmpC	AmpC + porin loss	OXY HPa	No β-lactamase	−	Potential	+
C. freundii	1		1					1
E. cloacae	2	2						2
E. coli	86	45	8	8	1		24	86
H. alvei	1		1					1
K. aerogenes	3		1		2			1	1	1c
K. oxytoca	11	4		1		5	1	11
K. pneumoniae	27	21	4				4	24	3
M. morganii	2		2					2
P. mirabilis	5	2	3					5
P. rettgeri	2	2						2
P. aeruginosa	5						5	5
Salmonella spp.	2	1	1					2
S. marcescens	3		3					3
Total	150	77	24	9	3	5	34	145	4	1

^aOXY HP, OXY hyperproduction. OXY-type cephalosporinases are intrinsic to K. oxytoca.

^b−, negative; +, positive; the “potential” heading refers to potential carbapenemase or potential impermeability and/or porin loss.

^cThe isolate was misclassified as class A carbapenemase positive.