Comparison of antimicrobial susceptibility of Glaesserella parasuis from different pig production systems in Taiwan between 2015 and 2020

Table 2 Minimum inhibitory concentration (MIC) distribution patterns, wild-type cutoff (CO_WT), and frequencies of wild-type (WT) and non-wild type (non-WT) isolates

Class (subclass)	Antimicrobial	MIC distribution pattern	Breakpoint^a (µg/mL)	CO_WT (µg/mL)	SD_MIC (log₂ µg/mL)	WT		Non-WT
Class (subclass)	Antimicrobial	MIC distribution pattern	Breakpoint^a (µg/mL)	CO_WT (µg/mL)	SD_MIC (log₂ µg/mL)	n	%	n	%
Beta lactams
(Penams)	Amoxicillin	Multi-modal	2	1	1.23	107	69.5	47	30.5
(Penams)	Ampicillin	Multi-modal	2	8	1.51^b	119	77.3	35	22.7
(Cephalosporins)	Ceftiofur	Multi-modal	8	0.06	0.6	82	53.2	72	46.8
(Cephalosporins)	Cephalothin	Unknown	N/A	64	2.94^b	154	100	0	0
Polymyxins	Colistin	Unimodal	N/A	2	0.84	144	93.5	10	6.5
Tetracyclines	Doxycycline	Unimodal	N/A	8	0.91	153	99.4	1	0.6
Fluoroquinolones	Enrofloxacin	Unimodal	1	32	1.62^b	150	97.4	4	2.6
Amphenicols	Florfenicol	Unimodal	8	16	1.56^b	151	98.1	3	1.9
Aminoglycosides	Gentamicin	Multi-modal	N/A	16	1.11	103	66.9	51	33.1
Aminoglycosides	Kanamycin	Multi-modal	N/A	32	0.86	96	62.3	58	37.7
Aminocyclitol	Spectinomycin	Unknown	N/A	64	1.07	34	22.1	120	77.9
Lincosamides	Lincomycin	Unknown	N/A	64	1.07	27	17.5	127	82.5
Lincosamides	Lincospectin (1:2)	Unknown	N/A	128	1.48^b	63	40.9	91	59.1
Pleuromutilin	Tiamulin	Multi-modal	32	64	1.41^b	133	86.4	21	13.6
Macrolides	Tilmicosin	Unknown	32	32,768	3.92^b	154	100	0	0
Macrolides	Tylosin	Unknown	N/A	32,768	3.37^b	154	100	0	0

^aBreakpoint for swine Pasteurella multocida and Actinobacillus pleuropneumoniae published in CLSI VET01S ED7:2024
^bstandard deviation of the CO_WT (SD_MIC) calculation was abnormal

ISSN: 2055-5660