Resistance trends in gram-negative bacteria: surveillance results from two Mexican hospitals, 2005–2010

BMC Research Notes

Table 5 Comparison of the in vitro activities of selected antimicrobial agents tested against Enterobacterspp . ^a (214 strains)

Antimicrobial agent	MIC₅₀	MIC₉₀	Range	%susceptible / resistant^b
Ceftriaxone	0.25	>32	≤0.25 – >32	59.3 / 39.2
Ceftazidime	≤1	>16	≤1 – >16	62.6 / 34.5
Cefepime	≤0.12	8	≤0.12 – >16	92.1 / 3.7
Piperacillin / tazobactam	2	>64	≤0.5 – >64	73.8 / 26.1
Imipenem	0.5	1	≤0.12 – 8	98.6 / 0.0
Meropenem	≤0.12	0.12	≤0.12 – 4	100.0 / 0.0
Ciprofloxacin	≤0.03	>4	≤0.03 – >4	85.0 / 14.0
Levofloxacin	≤0.5	>4	≤0.5 – >4	87.4 / 12.6
Gentamicin	≤2	>8	≤2 – >8	81.3 / 18.6
Amikacin	2	>32	≤4 – >32	82.7 / 16.3
PolymyxinB	≤0.5	>4	≤0.5 – >4	- / -
Colistin	≤0.5	>4	≤0.5 – >4	- / -

^a Includes Enterobacteraerogenes (38 strains), Enterobacteramnigenus (2 strains), Enterobactercancerogenus (1 strain), Enterobacter cloacae (161 strains), Enterobactergergoviae (6 strains), Enterobactersakazakii (4 strains), and unspeciated Enterobacter (2 strains).
^b Criteria as published by the CLSI [16].