Table 2.

Sensitivity and specificity of different phenotypic methods in relation to PCR results for detection of blaNDM-1 production among carbapenem-resistant Acinetobacter isolates from late-onset VAP patients

Phenotypic tests		PCR results				Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Accuracy (%)
		Positive (n=42)		Negative (n=12)		52.38	41.67	75.86	20	50
		No	%	No	%
MHT	Positive	22	52.38	7	58.33
	Negative	20	47.62	5	41.67
CDT	Positive	39	92.86	2	16.67	92.86	83.33	95.12	76.92	90.74
	Negative	3	7.2	10	83.33

Abbreviations: blaNDM, New Delhi metallo-β-lactamase; MHT, modified Hodge test; CDT, combined disk test; PPV, positive predictive value; NPV, negative predictive value; VAP, ventilator-associated pneumonia.