Table 4.

CRE: MALDI-TOF MS hydrolysis of Ertapenem and Imipenem.

Resistance	Organism (N)	Ertapenem % hydrolysis by time			Imipenem % hydrolysis by time
		2 h	3 h	4 h	1 h	2 h
Mechanisma (N)
		% POS	% POS	% POS	% POS	% POS
IMI (3)	Enterobacter cloacae (3)	100			100
IMP 1 (2)	Enterobacter aerogenes (1)	100			100
	Klebsiella pneumoniae (1)	100			100
IMP 4 (1)	Klebsiella pneumoniae (1)	100			100
KPC (23)	Klebsiella pneumoniae (12)	100			100
	Escherichia coli (2)	50	0	0	100
	Enterobacter cloacae (3)	100			100
	Proteus mirabilis (2)	100			50	100
	Klebsiella oxytoca (1)	100			100
	Kluyvera ascorbata (1)	100			100
	Morganella morganii (1)	100			100
	Raoultella ornithinolytica (1)	100			100
KPC 2 (4)	Klebsiella pneumoniae (4)	100			100
KPC 3 (15)	Escherichia coli (2)	100			100
	Klebsiella pneumoniae (13)	84.6(2)b	0(2)b	0(2)b	92.3(1)b	0(1)b
KPC 4 (1)	Klebsiella pneumoniae (1)	100			100
KPC+CTX-M-1 (1)	Enterobacter cloacae (1)	100			100
NDM+CTX-M-1 (1)	Escherichia coli (1)	100			100
NDM+OXA 232 (1)	Klebsiella pneumoniae (1)	100			100
NDM (19)	Citrobacter freundii (1)	100			100
	Escherichia coli (7)	100			100
	Klebsiella pneumoniae (9)	88.9	100	100	100
	Proteus mirabilis (1)	0	0	0	100
	Salmonella sv. Seftenberg (1)	100			100
NDM 1 (2)	Klebsiella pneumoniae (2)	100			100
NDM 5 (2)	Escherichia coli (2)	100			100
NDM 6 (2)	Escherichia coli (2)	100			100
OXA 48 (6)	Klebsiella pneumoniae (6)	66.7	100	50	100
OXA 181 (3)	Klebsiella pneumoniae (3)	100			100
SME (7)	Serratia marcescens (7)	100			100
VIM (2)	Enterobacter cloacae (1)	100			100
	Klebsiella pneumoniae (1)	100			100
VIM 27 (1)	Klebsiella pneumoniae (1)	100			100
Initial % +		92.7			97.9
Post DAc % +		94.7			98.9

^adetermined by PCR or whole genome sequencing.

^bcured plasmid hence not 100%.

^cDA, discrepant analysis.