Molecular Analysis of Ciprofloxacin Resistance Mechanisms in Malaysian ESBL-Producing Klebsiella pneumoniae Isolates and Development of Mismatch Amplification Mutation Assays (MAMA) for Rapid Detection of gyrA and parC Mutations

Table 1

Ciprofloxacin susceptibility patterns and fluoroquinolone (FQ) resistance determinants detected in the 93 K. pneumoniae isolates investigated in this study.

Ciprofloxacin susceptibility	MIC (𝜇g/mL)	Number of isolates	FQ resistance determinants		Total number of gyrA and/or parC alterations	Total number of FQ resistance determinants
			PMQR* genes (𝑛)	gyrA and/or parC alterations (𝑛)
Susceptible; (𝑛=27, 29%)	0.032–0.047	2	None (2)	None (2)	None	None
	0.094–0.38	12	aac(6 ′ )-Ib-cr (12)	None (12)	None	1
	0.5–0.75	5	qnrB (2), qnrS (1); None (2)	None (3); gyrA83 (2)	None; 1	1; 1
	1	8	qnrB + aac(6′)-Ib-cr (5); qnrB (3)	None (5); gyrA83 (3)	None; 1	2; 2
Intermediately susceptible; (𝑛=32, 34%)	2	32	qnrB + aac(6′)-Ib-cr (29); qnrB (3)	None (29); gyrA83 (3)	None; 1	2; 2
Resistant; (𝑛=34, 37%)	4–6	4	None (4)	gyrA83 + parC80 (4)	2	2
	≥32	30	qnrB + aac(6′)-Ib-cr (8); qnrB + aac(6′)-Ib-cr (2); qnrB + aac(6′)-Ib-cr (1); qnrB + aac(6′)-Ib-cr (1), aac(6′)-Ib-cr (2); qnrB + aac(6′)-Ib-cr (1)	gyrA83 + parC80 (10); gyrA83 + parC84 (2); gyrA83 + gyrA87 (1); gyrA83 + gyrA87 + parC80 (16); None (1)	2; 2; 2; 3; None	2 or 4; 4; 4; 3–5; 2

∗PMQR: Plasmid-mediated quinolone resistance.