title: An animal source for the ROB-1 beta-lactamase of Haemophilus influenzae type b.
abstract: The most common cause of ampicillin resistance in Haemophilus influenzae type b is production of TEM-1 beta-lactamase; however, a novel enzyme with a similar substrate profile but a quite different isoelectric point has also been described. This beta-lactamase, designated ROB-1, has not been found previously in any other organism. In a survey of 46 ampicillin-resistant H. influenzae type b isolates, we found a second human isolate that produces ROB-1 and discovered that ampicillin-resistant isolates of the porcine pathogen Haemophilus pleuropneumoniae also produced ROB-1. In both Haemophilus species ROB-1 production was determined by plasmids that had considerable DNA sequence homology. However, the ROB-1 and TEM-1 beta-lactamase genes were not related. Our findings suggest that this form of ampicillin resistance has an animal reservoir and that conditions fostering its prevalence in animal strains may play a role in the spread of resistance to human pathogens.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D005798:Genes, Bacterial; D006190:Haemophilus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006192:Haemophilus Infections / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D007526:Isoelectric Point; D008583:Meningitis, Haemophilus / Q000382:microbiology; D009693:Nucleic Acid Hybridization; D010403:Penicillin Resistance; D011815:R Factors; D013552:Swine; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000667:Ampicillin; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1