Table 8. Relationship between the overexpression of RND pumps and the susceptibility of Pseudomonas aeruginosa isolates to antibiotic

	Number of strains resisted against								Total of overexpression strains1)
	CEP	CEF	IMI	MER	GEN	AMI	CIP	LEV
MexCD-OprJ	9	7	10	10	8	6	10	11	13
p-value2)	0.024	0.328	0.512	0.122	0.185	0.351	0.01	0.01
MexEF-OprN	18	18	24	20	20	12	24	27	32
p-value2)	0.013	0.005	0.143	0.775	0.001	0.447	<0.01	<0.01
Total of resistant strains3)	24	23	39	34	25	19	27	30

The number of strains that resisted against Piperaclin/tazobactam and Colistin was low and not reliable for analysis by Chi-square test, thus these data were removed from the Table.
The total number of strains that overexpressed certain types of efflux pump, without considering antibiotic resistance properties.
p-values were calculated by Pearson’s Chi-squared test with Yates’ continuity correction or Fisher’s exact test for count data.
The total number of strains that resisted certain types of antibiotics, without considering which efflux pumps these strains overexpressed.
RND, resistance nodulation division; CEP, cefepime; CEF, ceftazidime; IM, imipenem; MER, meropenem; GEN, gentamicin; AMI, amikacin; CIP, ciprofloxacin; LEV, levofloxacin.