Open AccessPSE-4 Beta Lactamase: A Serotype-Specific Enzyme in Pseudomonas Aeruginosa
Author(s) -
David M. Livermore,
Tyrone Pitt,
Christopher S. Jones,
Judy A. Crees-Morris,
Ruth Williams
Publication year - 1985
Publication title -
journal of medical microbiology/journal of medical microbiology
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 117
eISSN - 1473-5644
pISSN - 0022-2615
DOI - 10.1099/00222615-19-1-45
Subject(s) - serotype , microbiology and biotechnology , pseudomonas aeruginosa , carbenicillin , biology , spectinomycin , penicillin , virology , antibiotics , bacteria , gentamicin , genetics
PSE-4 enzyme is the most common plasmidic beta lactamase in Pseudomonas aeruginosa but its production is invariably non-transferable by conjugation. Of 20 PSE-4+ isolates from 10 separate sources, 16 were serotype O:16 and two belonged to the related O:2(b) serotype. One of the two remaining organisms was not O-typable and the other was agglutinated by several unrelated antisera. Examination of additional O:16 strains confirmed the unusual frequency of PSE-4 enzyme in this serotype. None of the PSE-4+ strains was able to transfer carbenicillin resistance in mating experiments and none contained extrachromosomal DNA. Two explanations of the relationship between enzyme production and O antigenicity are proposed. PSE-4 production may be transmissible, perhaps by transduction, between strains of O:16 or related serotypes, or PSE-4+ P. aeruginosa may represent a disseminated subtype. A third hypothesis, that the PSE-4 coding element carried serotype determinants, was discounted. PSE-4+ and PSE-4- P. aeruginosa strains of O:16 and related serotypes were found to represent a definite cluster by their phage-susceptibility pattern and pyocin type (type 1). The only characters linked to PSE-4 production were resistance to spectinomycin, streptomycin and sulphonamide and the genes responsible for these characters seemed to occur on the PSE-4 coding element.