TABLE 2.

Microbiological characteristics of MDR-HV K. pneumoniae strains

Strain	Capsular type	ST type	Antimicrobial resistance patterna	β-lactamase	Efflux pump overexpression and quinolone resistance mechanism
KP0175	K2	86	Non-susceptibility to CZ (MIC ≥ 64 μg/mL), CXM (MIC = 16 μg/mL), FOX (MIC = 32 μg/mL), CRO (MIC = 8 μg/mL), CAZ (MIC ≥ 16 μg/mL), and SAM (MIC ≥ 32 μg/mL)	SHV-1, CMY-2b
KP0430	K2	65	Non-susceptibility to CXM (MIC = 32 μg/mL), SAM (MIC = 16 μg/mL), and TGC (MIC = 4 μg/mL)	SHV-11	Overexpression of AcrAB efflux pump; missense mutations in ramR (G42V and I141T)
KP0971	K2	380	Non-susceptibility to CZ (MIC = 16 μg/mL), SAM (MIC ≥ 32 μg/mL), and TZP (MIC = 32 μg/mL)	SHV-1, TEM-1
KP1290	K5	1049	Non-susceptibility to CXM (MIC = 16 μg/mL); CIP (MIC = 1 μg/mL), and TGC (MIC = 2 μg/mL)	SHV-11	Overexpression of OqxAB efflux pump; missense mutations in oqxR (R5C)
KP1371	K2	86	Non-susceptibility to CXM (MIC ≥ 64 μg/mL), SAM (MIC ≥ 32 μg/mL), and TGC (MIC = 4 μg/mL)	SHV-1	Overexpression of AcrAB efflux pump; truncation of ramR
KP1562	K1	23	Non-susceptibility to CZ (MIC ≥ 64 μg/mL), CXM (MIC ≥ 64 μg/mL), CRO (MIC = 16 μg/mL), CAZ (MIC ≥ 64 μg/mL), CIP (MIC = 1 μg/mL), and GM (MIC ≥ 16 μg/mL)	SHV-5c	Presence of qnrS
KP1810	K16	660	Non-susceptibility to CXM (MIC = 16 μg/mL), FOX (MIC = 32 μg/mL) and TGC (MIC = 2 μg/mL)	SHV-1	Overexpression of AcrAB efflux pump; missense mutation in ramR (G180C)
KP1859	K1	23	Non-susceptibility to CXM (MIC = 16 μg/mL), CIP (MIC = 1 μg/mL), and TGC (MIC = 3 μg/mL)	SHV-11	Overexpression of OqxAB efflux pump; missense mutations in oqxR (Y80D)
KP2301	K5	1049	Non-susceptibility to CXM (MIC = 16 μg/mL), CIP (MIC = 1 μg/mL), and TGC (MIC = 2 μg/mL)	SHV-11	Overexpression of OqxAB efflux pump; missense mutations in oqxR (S82L, E118G and Q119G); and Ala insertion between amino acid positions 118 and 119
KP2371	K1	8	Non-susceptibility to CXM (MIC = 16 μg/mL), CIP (MIC = 1 μg/mL), and TGC (MIC = 3 μg/mL)	SHV-1	Overexpression of OqxAB efflux pump; putative mutation of OqxR-binding site of oqxAB promotor
KP2484	K1	23	Non-susceptibility to CZ (MIC ≥ 64 μg/mL), CXM (MIC = 16 μg/mL), FOX (MIC ≥ 64 μg/mL) and SAM (MIC ≥ 32 μg/mL)	SHV-11, DHA-1b
KP2485	K1	23	Non-susceptibility to CXM (MIC = 16 μg/mL), CIP (MIC ≥ 4 μg/mL), and TGC (MIC = 2 μg/mL)	SHV-11	Overexpression of OqxAB efflux pump; missense mutations in oqxR (L14F); amino acid substitution of GyrA in S83F; and the presence of qnrS
KP2611	K1	23	Non-susceptibility to CZ (MIC ≥ 64 μg/mL), CXM (MIC = 16 μg/mL), CRO (MIC ≥ 64 μg/mL), CAZ (MIC = 16 μg/mL), and CIP (MIC = 1 μg/mL)	SHV-11 SHV-12c	The presence of qnrS1 and aac(6’)-Ib

^aCZ, cefazolin; CXM, cefuroxime; FOX, cefoxitin; CRO, ceftriaxone; CAZ, ceftazidime; SAM, ampicillin-sulbactam; TZP, piperacillin-tazobactam; GM, gentamicin; TGC, tigecycline; SXT, trimethoprim-sulfamethoxazole; CIP, ciprofloxacin.

^bPlasmid-mediated AmpC β-lactamase.

^cExtended-spectrum β-lactamase.