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G A Jacoby

Publications and source records attributed to G A Jacoby.

At least 55 records · Page 3Linked to original sources
PubMed1988

Evaluation of plasmid-encoded beta-lactamase resistance in Escherichia coli blood culture isolates.

The frequency of beta-lactam resistance was determined among 313 strains of Escherichia coli, 119 of Enterobacter/Klebsiella/Proteus spp., and 48 of Pseudomonas spp. isolated from blood cultures (at Turku University Central Hospital and Turku City Hospital) in 1983-1987. During this period the MIC50 of ampicillin for Escherichia coli increased from 8 to 32 micrograms/ml, the MIC90 of piperacillin from 16 to greater than 32 micrograms/ml and the MIC90 of cefuroxime from 4-8 to 16 micrograms/ml. Among 172 ampicillin-resistant isolates beta-lactamase-mediated resistance was characterized by DNA hybridization with TEM-1, SHV-1, OXA-1, OXA-2, PSE-1, PSE-2 and PSE-4 beta-lactamase probes and by isoelectric focusing. Beta-lactamase types found were TEM-1, TEM-2, SHV-1 and OXA-1. Isoelectric focusing did not show any other plasmid-mediated beta-lactamase varieties. Piperacillin-resistant strains showed mostly TEM-1 activity, but also produced OXA-1 and chromosomal beta-lactamase. Interestingly, a decrease in cefuroxime susceptibility in Escherichia coli occurred in a few OXA-1 producing strains as well as in strains that produced only chromosomal beta-lactamase. Two Escherichia coli strains that overproduced chromosomal beta-lactamase had increased ceftazidime MIC values (8-16 micrograms/ml).

Ampicillin↗
PubMed1988

Molecular structure and interrelationships of multiresistance beta-lactamase transposons.

Transposons coding for beta-lactamases OXA-3, OXA-4, OXA-5, LCR-1, and CARB-3 have been isolated and compared functionally and structurally with transposons for TEM-1, OXA-1, PSE-1, PSE-2, and PSE-4 enzymes. Each beta-lactamase gene type occurred in a unit together with resistance to other antibiotics, particularly streptomycin and sulfonamide but also chloramphenicol, mercuric ion, or gentamicin, kanamycin, and tobramycin. Restriction mapping, gene cloning, and DNA hybridization were used to compare the transposons and to localize their functional components. Although the multiresistance beta-lactamase transposons varied in size from 8 to 25 kb, the similarity of some of their restriction maps suggested a common derivation. Six of 12 transposons contained DNA segments homologous to the tnpR gene of transposon Tn21 and could complement a tnpR- Tn21 derivative. Consequently, these six transposons appear to have evolved from a common progenitor by acquisition of DNA coding for various beta-lactamases and other resistance genes.

DNA Restriction Enzymes↗
PubMed1988

Reliability of biotinylated DNA probes in colony hybridization: evaluation of an improved colony lysis method for detection of TEM-1 beta-lactamase.

Utilizing an improved method for colony hybridization developed by Haas & Fleming, biotin and 32P-labelled TEM-1 probes were compared for sensitivity and specificity in identifying the type of beta-lactamase made by over 100 clinical bacterial isolates. The new procedure was more reliable than a standard one, but still gave more than 20% false positive and false negative reactions.

Bacteria↗
PubMed1988

Sequence of PSE-2 beta-lactamase.

The nucleotide sequence of PSE-2 beta-lactamase, an enzyme that readily hydrolyzes both carbenicillin and oxacillin, has been determined. The deduced sequence of 266 amino acids contained 93 residues identical to those of OXA-2 beta-lactamase and the Ser-Thr-Phe-Lys tetrad also found in the active site of TEM-1 beta-lactamase.

Amino Acid Sequence↗
PubMed1988

Detection of plasmid-mediated beta-lactamases with DNA probes.

beta-Lactamase identification by colony hybridization with 32P-labeled DNA probes for TEM-1, SHV-1, OXA-1, OXA-2, PSE-1, PSE-2, and PSE-4 was compared with isoelectric focusing in 122 clinical isolates making a variety of enzyme types. All strains producing a probe-type enzyme gave a positive hybridization reaction. Cross-hybridization was observed between TEM-1 and TEM-2 or TLE-1, between SHV-1 and SHV-2, between OXA-1 and OXA-4, between OXA-2 and OXA-3 (weak), between PSE-2 and OXA-6 or OXA-5 (weak), and among PSE-1, PSE-4, and CARB-3. With allowance for such cross-hybridization, only six strains gave false-positive reactions, and the procedure was 99% specific.

Bacteria↗
PubMed1987

Molecular cloning and DNA homology of plasmid-mediated beta-lactamase genes.

Molecular cloning of DNA fragments between 1.5 and 8 kb from BamHI, EcoRI, HindIII, SalI, or Sau3A digests permitted the isolation of structural genes coding for TEM-1, ROB-1, OXA-1, OXA-3, OXA-4, OXA-5, PSE-1, PSE-2, PSE-3, PSE-4, CARB-3, CARB-4, AER-1, and LCR-1 beta-lactamases. Ampicillin-resistant clones were selected and it was confirmed that they contained the respective beta-lactamase genes by isoelectric focusing. Detailed physical maps of 14 different recombinant plasmids were constructed using 8 restriction endonucleases. Plasmid deletions and lacZ fusions were used to localize the beta-lactamase structural genes. DNA probes were constructed for the TEM-1, ROB-1, OXA-1, and PSE-1 genes. Under conditions of high stringency, hybridization was observed between the genes for TEM-1 and TEM-2 or TLE-1, OXA-1 and OXA-4, and PSE-1 and PSE-4 or CARB-3, while the ROB-1 gene probe showed no cross-hybridization. Such bla gene probes should facilitate studies of beta-lactamase molecular epidemiology.

Cloning, Molecular↗
PubMed1986

New plasmid-mediated oxacillin-hydrolyzing beta-lactamase in Pseudomonas aeruginosa.

A novel type of oxacillin-hydrolyzing beta-lactamase, termed OXA-4, has been detected in three Pseudomonas aeruginosa strains isolated in Paris between 1977 and 1981. The strains contained similar plasmids that determined resistance to carbenicillin, chloramphenicol, gentamicin, kanamycin, streptomycin, sulphonamide, tetracycline, tobramycin, sodium borate, and mercuric chloride, had a size of approximately 150 megadaltons, and belonged to the P-5 incompatibility group. Compared to reference OXA-1 beta-lactamase produced by plasmid RGN238, OXA-4 beta-lactamase produced by these plasmids had a similar substrate profile, similar response to inhibitors, and identical immunological reactions but differed in isoelectric point. In a more recent survey of 10 French hospitals plasmid-determined OXA-4 beta-lactamase production was found in P. aeruginosa isolates from four hospitals in the Paris area.

Drug Resistance, Microbial↗
PubMed1986

An animal source for the ROB-1 beta-lactamase of Haemophilus influenzae type b.

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.

Ampicillin↗
PubMed1985

Genetic and biochemical properties of AER-1, a novel carbenicillin-hydrolyzing beta-lactamase from Aeromonas hydrophila.

A novel carbenicillin-hydrolyzing beta-lactamase has been discovered in a blood isolate of Aeromonas hydrophila. The enzyme resembles plasmid-determined carbenicillinases in substrate profile but differs in isoelectric point (pI 5.9) and molecular weight (22,000) and has been termed AER-1. No evidence for a plasmid location could be obtained in A. hydrophila, but the AER-1 gene and resistance to chloramphenicol, streptomycin, and sulfonamide could be transferred by mobilization with IncP plasmids to Escherichia coli, where the gene cluster inserted at a unique chromosomal site. The linked resistances are similar to those found on multiresistance beta-lactamase transposons, but since insertion of the A. hydrophila gene cluster was site specific and recA+ dependent, the cluster is not a functional transposon.

Aeromonas↗
PubMed1985

Five novel plasmid-determined beta-lactamases.

Five novel plasmid-determined beta-lactamases named TLE-1, OXA-4, OXA-5, OXA-6, and OXA-7 were detected in ampicillin-resistant isolates of Escherichia coli and carbenicillin-resistant strains of Pseudomonas aeruginosa. TLE-1 resembled TEM-1 in substrate profile and reactions with inhibitors but differed in isoelectric point (5.55) and enzyme banding pattern on flat-bed electrofocusing.OXA-4, OXA-5, OXA-6, and OXA-7 hydrolyzed oxacillin, methicillin, and cloxacillin readily but differed from OXA-1, OXA-2, and OXA-3 in substrate profiles, inhibitor reactions, and isoelectric points (7.5 to 7.8).OXA-4 and OXA-6 were unusual for members of the OXA group in their sensitivity to inhibition by cloxacillin. OXA-5 and OXA-7 had isoelectric points close to that of SHV-1, emphasizing the need in beta-lactamase classification for studies in addition to isoelectric focusing. These five new enzymes bring the number of plasmid-determined beta-lactamases known in gram-negative organisms to more than 20. The evolution of such enzymatic diversity remains to be explored.

Anti-Bacterial Agents↗
PubMed1985

beta-Lactamases and beta-lactam resistance in Escherichia coli.

Escherichia coli strains determining 17 different plasmid-determined beta-lactamases were tested for resistance to new broad-spectrum beta-lactam antibiotics. Several beta-lactamases demonstrated enhanced resistance to cefamandole but only low-level resistance to other agents. High production of cloned E. coli chromosomal beta-lactamase, however, provided resistance to cefamandole, cefoxitin, cefotaxime, ceftazidime, and aztreonam but not to BMY-28142 or imipenem.

Anti-Bacterial Agents↗
PubMed1983

Properties of IncP-2 plasmids of Pseudomonas spp.

Thirty IncP-2 R plasmids from isolates of Pseudomonas spp. of diverse geographical origins were examined for the production of resistance properties. All the plasmids determined resistance to tellurite and all inhibited the propagation of certain DNA phages, although several patterns of phage inhibition were detected. Of the 30 plasmids, 29 determined resistance to streptomycin, 28 determined resistance to mercuric ion, and 24 determined resistance to sulfonamide. Resistance to other antibiotics, to compounds of arsenic, boron, or chromium, and to UV irradiation was less common. The degradative plasmid CAM also belonged to this group. When CAM was introduced into recipients carrying an IncP-2 R plasmid, recombinant plasmids were often formed in which antibiotic resistance and the ability to grow on camphor were transferred together to further recipients or were lost together in a strain in which IncP-2 plasmids were unstable. Such hybrid plasmid formation was rec dependent. CAM and other IncP-2 plasmids that determine UV light resistance demonstrated UV-enhanced, nonpolarized transfer of the Pseudomonas aeruginosa chromosome. By agarose gel electrophoresis, all IncP-2 R plasmids and CAM were ca. 300 X 10(6) in molecular weight.

Conjugation, Genetic↗
PubMed1983

Properties of PSE-2 beta-lactamase and genetic basis for its production in Pseudomonas aeruginosa.

The properties of PSE-2 beta-lactamase have been examined by using two new PSE-2-producing plasmids, pMG33 and pMG74, as well as plasmid R151, found in Pseudomonas aeruginosa. PSE-2 beta-lactamase resembled other PSE enzymes in activity against carbenicillin, but it also resembled OXA enzymes, such as OXA-1, in rapid hydrolysis of oxacillin, cloxacillin, and methicillin and in inhibition by sodium chloride but not by cloxacillin. Antisera that inactivated TEM-1, TEM-2, OXA-1, or PSE-1 and PSE-4 beta-lactamase failed to cross-react with PSE-2, which thus appears to be immunologically distinct. The plasmids determining PSE-2 varied in geographical origin, size, transfer proficiency, and incompatibility specificity, but all determined resistance to carbenicillin, gentamicin, kanamycin, streptomycin, spectinomycin, sulfonamide, and tobramycin. From a pUZ8-R151 recombinant plasmid in Escherichia coli, the PSE-2 beta-lactamase gene could be transposed to a second plasmid in a 6.4-megadalton unit together with resistance to gentamicin, kanamycin, streptomycin, spectinomycin, sulfonamide, and tobramycin. Transposition was recA independent. We propose the designation Tn1404 for this unit, which, like transposons carrying OXA-1, PSE-1, PSE-4, and some transposons determining TEM-1, includes genes for beta-lactam, aminoglycoside, and sulfonamide resistance.

Bacteriophages↗
PubMed1982

Amikacin, gentamicin and tobramycin resistant Pseudomonas aeruginosa in a leukaemic ward. Epidemiology and genetic studies.

Four patients in a leukaemic ward were infected with multi-resistant Pseudomonas aeruginosa. Similar organisms were found in the environment and it appeared that lapses in aseptic routine contributed to the outbreak. Serological, bacteriophage and pyocin-typing revealed that a fifth patient was infected with a distinct strain, but agarose gel electrophoresis indicated that all patient and environmental strains carried the same plasmid. The plasmid had a molecular weight of 47 (s.d. +/- 2) X 10(6) dal and was transfer deficient. It conferred resistance to carbenicillin, gentamicin, kanamycin, streptomycin, sulphonamide, tetracycline and tobramycin and determined an aminoglycoside adenylyltransferase active against amikacin in-vitro and not in-vivo. Spread of this non-transferable plasmid to a different Ps. aeruginosa strain and dissemination of multi-resistant organisms led to serious infections.

Adult↗
PubMed1982

Effects of azlocillin in combination with clavulanic acid, sulbactam, and N-formimidoyl thienamycin against beta-lactamase-producing, carbenicillin-resistant Pseudomonas aeruginosa.

We investigated the effects of the combination of azlocillin with the beta-lactamase inhibitors clavulanic acid and sulbactam and with N-formimidoyl thienamycin against strains of Pseudomonas aeruginosa with R-factor-mediated carbenicillin resistance. The 10 strains tested (1 R-, 9 R+) were isogenic, except for the presence of individual plasmids determining each of nine plasmid-mediated beta-lactamases found in P. aeruginosa. We utilized a checkerboard technique for testing antibiotic combinations. Low concentrations of clavulanic acid produced synergy with azlocillin against the strains producing the TEM-1, TEM-2, PSE-1, PSE-3, and PSE-4 beta-lactamases; for the strains producing the OXA-1, OXA-2, OXA-3, and PSE-2 beta-lactamases, such synergy was not found. With sulbactam, synergy was demonstrated in all strains except that producing PSE-2 beta-lactamase; for several strains, however, the concentration of sulbactam required to produce synergy was substantially higher than that for clavulanic acid. N-Formimidoyl thienamycin was highly active as a single agent against all of the strains, regardless of beta-lactamase production. The combination of N-formimidoyl thienamycin and azlocillin produced synergy against only two of the strains tested.

Azlocillin↗