Molecular distribution of ROB-1 beta-lactamase in Actinobacillus pleuropneumoniae.
The plasmid content and molecular distribution of the ROB-1 beta-lactamase was investigated in 31 swine isolates of Actinobacillus pleuropneumoniae. Three types of plasmid patterns were observed in ampicillin-resistant isolates: a predominant one consisting of 2.6-, 2.9-, and 5.0-kb plasmids and two other patterns consisting of 4.2- and 5.5-kb plasmids and of a 6.8-kb plasmid. Plasmid DNA preparations were hybridized with a blaROB-1 intragenic fragment from the Haemophilus influenzae Rrob plasmid. Positive hybridizations were observed with all ampicillin-resistant isolates. The blaROB-1 gene was found on 3 plasmids of 2.6, 5.5, and 6.8 kb. One swine isolate of Pasteurella multocida also had a 2.6-kb plasmid bearing blaROB-1. ROB-1 was confirmed in typical isolates by isoelectric focusing and blaROB-1 sequences were confirmed by polymerase chain reaction amplification with an intragenic set of primers. Plasmids bearing blaROB-1 were successfully electro-transformed in a susceptible A. pleuropneumoniae isolate. These results emphasize the importance of ROB-1 in A. pleuropneumoniae and identify a possible reservoir of beta-lactam resistance.
Départment de Microbiologie, Faculté de Médecine, Université Laval, Québec, Canada.
J M
JM
Juteau
M
M
Sirois
A A
AA
Medeiros
R C
RC
Levesque
D000188:Actinobacillus / Q000201:enzymology*; D000668:Ampicillin Resistance / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D015342:DNA Probes / Q000138:chemical synthesis; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction; D013045:Species Specificity; D013552:Swine; D014162:Transfection; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D015342:DNA Probes; D004269:DNA, Bacterial; C071165:beta-lactamse ROB-1; D001618:beta-Lactamases