Table 1.
List of primers used in this study.
Fig 1.
Antimicrobial susceptibility of the PQ/CIP-resistant isolates.
The heat map shows the antimicrobial susceptibility patterns of 70 PQ/CIP-resistant isolates determined using the standard disk diffusion. Isolates that showed increased antibiotic resistance (smaller zone of inhibition ≥ 5 mm than the K279a wild-type) were marked in yellow, while colonies that are judged as resistant according to the CLSI guidelines (2022) were marked in red. AK, amikacin; GM, gentamicin; CIP, ciprofloxacin; LEV, levofloxacin; CAZ, ceftazidime; C, chloramphenicol; AMC, amoxicillin/clavulanic acid; SXT, co-trimoxazole.
Fig 2.
Antimicrobial susceptibility profiles of S. maltophilia strains.
Antimicrobial susceptibility profiles of wild-type K279a, KPQC3, KPQC13, KPQC22, KPQC24, and KPQC29 (A); and K279a harboring pBBR1MSC-3 (K279a/pBBR) and KPQC13 harboring pAcnA (KPQC13/pAcnA) or pBBR1MCS-3 vector (KPQC13/pBBR) (B) were determined using the standard disk diffusion. AK, amikacin; GM, gentamicin; NET, netilmicin; NA. nalidixic acid; CIP, ciprofloxacin; LEV, levofloxacin; MXF, moxifloxacin; CAZ, ceftazidime; CFP, cefoperazone; C, chloramphenicol; SXT, co-trimoxazole; MEM, meropenem; AZM, azithromycin; PB, polymyxin B; AMC, amoxicillin/clavulanic acid. Paraquat (PQ), menadione (MD), and phenazine (PNZ) were the representatives of superoxide generators. N indicates no inhibition zone. Asterisk (*) in (A) indicates significant difference relative to K279a (p-value < 0.05, ANOVA and Dunnett’s post-hoc test), while in (B) indicates significant difference between KPQC13/pBBR and KPQC13/pAcnA (p-value < 0.05, paired t-test).
Table 2.
Mutational analysis of the selected mutants.
Table 3.
Expression profiles of the antimicrobial resistance genes in the S. maltophilia mutants.