Characteristics of Clostridium difficile isolates and the burden of hospital-acquired Clostridium difficile infection in a tertiary teaching hospital in Chongqing, Southwest China

Table 3 The drug susceptibility results and MIC ranges of all the 55 C. difficile isolates

Antimicrobial agent	Resistance breakpoints and ECOFFs (ug/ml)	All strains(n = 55)				A + B+ strains(n = 35)				A-B- strains(n = 17)				A-B + strains(n = 3)
		MIC (ug/ml)			% of isolates	MIC (ug/ml)			% of isolates	MIC (ug/ml)			% of isolates	MIC (ug/ml)			% of isolates
		MIC₅₀	MIC₉₀	Range	R	MIC₅₀	MIC₉₀	Range	R	MIC₅₀	MIC₉₀	Range	R	MIC₅₀	MIC₉₀	Range	R
Vancomycin^a	> 2	0.5	0.5	0.125–1	0	0.5	0.5	0.5–1	0	0.5	0.5	0.25–0.5	0	0.5	0.5	0.125–0.5	0
Metronidazole^b	> = 32	0.25	0.25	0.125–1	0	0.25	0.25	0.125–1	0	0.125	0.25	0.125–0.25	0	0.125	0.25	0.125–0.25	0
Rifampin^c	> = 8	0.0625	256	0.0625–512	12.7	0.0625	0.0625	0.0625–512	2.9	256	512	0.0625–512	66.7	0.0625	512	0.0625–512	23.5
Levofloxacin^c	> = 8	2	128	0.5–128	14.5	2	2	0.5–128	2.9	8	128	2–128	66.7	2	128	0.5–128	29.4
Erythromycin^c	> = 8	256	512	2–512	87.3	256	512	2–512	82.9	512	512	512–512	100	64	512	2–512	94.1
Clindamycin^b	> = 8	16	256	0.5–256	61.8	8	256	0.5–256	57.1	256	256	128–256	100	128	256	0.5–256	64.7
Tigecycline^d	> 0.25	0.0625	0.0625	0.0625–0.0625	0	0.0625	0.0625	0.0625–0.0625	0	0.0625	0.0625	0.0625–0.0625	0	0.0625	0.0625	0.0625–0.0625	0

MIC minimum inhibitory concentration, ^aFor vancomycin, MIC breakpoint is recommended by the EUCAST (2019); ^bThe applied MIC breakpoints are those recommended for anaerobes by the CLSI (2019), M100 29th ed.; ^cBreakpoints were suggested by Chen Lidan et al. [14]; ^dFor tigecycline, MICs were compared to the EUCAST (2019) epidemiological cut-off value (0.25 μg/ml)

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