Exploring New Delhi Metallo Beta Lactamases in Klebsiella pneumoniae and Escherichia coli: genotypic vs. phenotypic insights

Table 2 Minimum inhibitory concentrations (MIC)

CREK	MIC μg/ ml	Imipenem	Meropenem	Doxycycline	Gentamycin	Colistin	Tigecycline
Escherichia coli	2	0 (0%)	0 (0%)	0 (0%)	0 (0%)	38(82.6%)	30(65.2%)
	4	2 (4.3%)	0 (0%)	0 (0%)	5 (10.8%)	2 (4.3%)	3 (6.5%)
	8	35 (76%)	0 (0%)	0 (0%)	1 (2.1%)	6 (13.0%)	13(28.2%)
	16	5 (10.8%)	46 (100%)	20 (43.4%)	40 (86.9%)	0 (0%)	0 (0%)
	32	1 (2.1%)	0 (0%)	26 (56.52%)	0 (0%)	0 (0%)	0 (0%)
	64	3 (6.5%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)
Klebsiella pneumoniae	2	1 (0.8%)	(0%)	0 (0%)	10 (8.7%)	100(87.7%)	78 (68.4%)
	4	4 (3.5%)	(0%)	3 (2.63%)	1 (0.87%)	3 (2.6%)	16 (14.0%)
	8	3 (2.6%)	(0%)	3 (2.63%)	2 (1.75%)	11 (9.6%)	16 (14.0%)
	16	92(80.7%)	114(100%)	108(94.7%)	101(88.5%)	0 (0%)	4 (3.5%)
	32	1 (0.8%)	(0%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)
	64	13 (11.4%	(0%)	0 (0%)	0 (0%)	0 (0%)	0 (0%)

The minimum inhibitory concentrations were determined using the agar diffusion method following CLSI guidelines. Breakpoint values against Escherichia coli and Klebsiella pneumoniae were as follows: imipenem and meropenem, sensitive (≤ 1), intermediate (2), and resistant (≥ 4); doxycycline and gentamicin, sensitive (≤ 4), intermediate (8), and resistant (≥ 16). Colistin was classified as intermediate at ≤ 2 and resistant at ≥ 4, while tigecycline was considered resistant at ≥ 2. Key; CREK, carbapenem-resistant E. coli and K. pneumoniae and MIC, Minimum inhibitory concentration.

ISSN: 1476-0711