Table 4.

β-Lactamase characterizations by nitrocefin hydrolysis with or without EDTA, isoelectric focusing, and PCR detection of gene sequences

IsolateSpecies identificationNitrocefin in EDTAaβ-Lactamase pIGene(s) identified by PCRb
04-059Escherichia coli+5.4, 9.0blaAmpC
11-025Sphingomonas paucimobilis+8.2, 8.8-9.3NDc
04-020Bacteroides fragilisNDblaCepA, blaCfiA
04-021Bacteroides helcogenes+5.0, 7.3blaCepA, blaCfiA
04-098Bacteroides ovatus+7.4blaCepA
04-092Bacteroides stercoris5.1blaCepA, blaCfiA, blaCblA
04-042Bacteroides suis+7.4, 7.8, 8.6ND
04-055Bacteroides suis4.3, 7.8blaCepA
04-049Bacteroides thetaiotaomicron7.3ND
04-036Bacteroides uniformis6.8, 7.3, 8.3blaCepA
03-041Desulfovibrio vulgaris4.9ND
04-076Hallela seregens4.5ND
P-41Bacillus cereusdNDbla I, bla II, bla III, blaTEM, bla C1
P-42Bacillus cereusdNDbla I, bla II, bla III, blaTEM, bla C1
11-022Bacillus cereus+9.1bla I, bla II, blaTEM
11-019Bacillus mycoidesNDbla I, bla II, bla III, blaTEM, bla C1
03-008Enterococcus casseliflavusNDClostridium perfringens bla, blaTEM
03-126Bifidobacterium breve+NDblaTEM
04-008Clostridium cocleatum4.5Clostridium perfringens bla, blaTEM
03-110Clostridium sp.+5.2ND
03-127Clostridium sp.+NDbla II, blaAmpC, blaTEM
03-013Eubacterium biforme+NDblaAmpC, blaSHV
  • a Nitrocefin hydrolysis prevented by EDTA shows inactivation of metallo-β-lactamases.

  • b β-Lactamase gene designations are the same as noted for oligonucleotides in Table 1.

  • c ND, none detected.

  • d The P-41 and P-42 isolates did not show positive nitrocefin reactions.