In Vivo Transfer of Plasmid-Encoded ACC-1 AmpC from Klebsiella pneumoniae to Escherichia coli in an Infant and Selection of Impermeability to Imipenem in K. pneumoniae

DOI: 10.1128/AAC.49.8.3562-3565.2005

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FIG. 1.
PFGE analysis. (A) PFGE patterns of SpeI-restricted DNA from K. pneumoniae. Lane 1, isolate K1; lanes 2 and 3, isolate K2; lane 4, outbreak isolate (SLK54) producing ACC-1 β-lactamase (14); lanes 5 to 8, unrelated strains of K. pneumoniae; lane M, molecular weight marker (lambda ladder; Bio-Rad). (B) PFGE patterns of NotI-restricted DNA from E. coli. Lanes 1 to 3, unrelated strains of E. coli; lane 4, isolate E1; lane 5, isolate E2; lane M, molecular weight marker (lambda ladder; Bio-Rad).
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FIG. 2.
Outer membrane protein profiles of K. pneumoniae clinical isolates K1 and K2 expressing ACC-1. Outer membrane proteins were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis in 12% acrylamide. Lane 1, molecular size standard; lane 2, isolate K1 (imipenem susceptible); lane 3, isolate K2 (imipenem resistant).

TABLE 1.

MICs of β-lactam drugs and strains characteristics

Isolate, strain or transconjugants	Species	Origin	β-Lactam resistance mechanism	MIC (μg/ml)^a
Isolate, strain or transconjugants	Species	Origin	β-Lactam resistance mechanism	AMX	FOX	CTX	CAZ	CPM	CPM (+ CLX)^b	IPM	IPM (+ CLX)	Associated resistance^c
K1	K. pneumoniae	Digestive flora	ACC-1 + TEM-1	>256	4	32	64	0.75	0.25	0.125	0.125	KTGNt + Sxt
K2	K. pneumoniae	Digestive flora	ACC-1 + TEM-1 + permeability alteration	>256	64	>32	96	16	1	8	0.25	KTGNt + Sxt
E1	E. coli	UTI^d	TEM-1	>256	4	0.064	0.25	0.094	ND^e	0.125	ND
E2	E. coli	Digestive flora	ACC-1 + TEM-1	>256	4	32	64	0.75	ND	0.125	ND	KTGNt + Sxt
J53	E. coli	Recipient strain		2	ND	0.032	0.047	0.016	ND	0.125	ND	Rif
J53-K1, J53-K2, J53-E2	E. coli	Transconjugants	ACC-1	>256	4	3	6	0.125	ND	0.125	ND	KTGNt + Rif

↵ a MICs were determined by the E-test method (Biodisk, Solna, Sweden). Abbreviations: AMX, amoxicillin; FOX, cefoxitin; CTX, cefotaxime; CAZ, ceftazidime; CPM, cefepime; IPM, imipenem.
↵ b MICs were determined on Mueller-Hinton agar containing cloxacillin (CLX) 250 μg/ml.
↵ c KTGNt, resistance to kanamycin, tobramycin, gentamicin, and netilmicin; Sxt, resistance to cotrimoxazole (trimethoprim-sulfamethoxazole); Rif, resistance to rifampin.
↵ d UTI, urinary tract infection.
↵ e ND, not determined.