Detection of 5 Kinds of Genes Related to Plasmid-Mediated Quinolone Resistance in Four Species of Nonfermenting Bacteria with 2 Drug Resistant Phenotypes

Objective. This study aimed to detect 5 kinds of genes related to plasmid-mediated quinolone resistance in four species of nonfermenting bacteria with 2 drug resistance phenotypes (multidrug resistance and pandrug resistance), which were Acinetobacter baumannii (Ab), Pseudomonas aeruginosa (Pa), Stenotrophomonas maltophilia (Sm), and Elizabethkingia meningoseptica (Em). Methods. The Phoenix NMIC/ID-109 panel and API 20NE panel were applied to 19 isolated strains, including 6 Ab strains (2 strains with multidrug resistance and 4 strains with pandrug resistance), 6 Pa strains (3 strains with multidrug resistance and 3 strains with pandrug resistance), 4 Sm strains (2 strains with multidrug resistance and 2 strains with pandrug resistance), and 3 Cm strains (2 strains with multidrug resistance and 1 strain with pandrug resistance). After strain identification and drug susceptibility test, PCR was applied to detect 5 genes related to plasmid-mediated quinolone resistance. The genes detected were quinolone resistance A (qnrA), aminoglycoside acetyltransferase ciprofloxacin resistance variant, acc(6′)-Ib-cr, and 3 integrons (intI1, intI2, and intI3). The amplified products were analyzed by 1% agarose gel electrophoresis and sequenced. Sequence alignment was carried out using the bioinformatics technique. Results. Of 19 strains tested, 8 strains carried acc(6′)-Ib-cr and 6 of them were of pandrug resistance phenotype (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of acc(6′)-Ib-cr was 60.0% for strains of pandrug resistance (6/10). Two strains were of multidrug resistance (1 Ab strain and 1 Pa strain), and the carrying rate of acc(6′)-Ib-cr was 22.0% (2/9). The carrying rate was significantly different between strains of multidrug resistance and pandrug resistance ( ). The class 1 integron was detected in 11 strains, among which 6 strains were of pandrug resistance (3 Ab strains, 2 Pa strains, and 1 Sm strain). The carrying rate of the class 1 integron was 60.0% (6/10). Five strains were of multidrug resistance (3 Pa strains, 1 Ab strain, and 1 Em strain), and the carrying rate was 55.6% (5/9). The carrying rate of the class 1 integron was not significantly different between strains of multidrug resistance and pandrug resistance ( ). Both acc(6′)-Ib-cr and intI1 were detected in 6 strains, which were negative for qnrA, intI2, and intI3. Conclusion. Quinolone resistance of isolated strains was related to acc(6′)-Ib-cr and intI1 but not to qnrA, intI2, or intI3. The carrying rate of acc(6′)-Ib-cr among the strains of pandrug resistance was much