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PubMed1976

Penicillinase-producing Gonococci in Liverpool.

Gonococci, which had acquired a TEM-type of penicillinase widely distributed among gram-negative bacilli, appeared in February, 1976, and soon accounted for 9% of isolates at a clinic in Liverpool. In 45 patients infected by such gonococci, the frequency of complications did not suggest reduced communicability or invasiveness, and usual forms of treatment with penicillins always failed. Spectinomycin succeeded in 21 (95%) of 22 patients treated, blt tetracyclines succeeded in only 13 (68%) of 19. Appropriate laboratory tests for recognising penicillinase-producing gonococci must be used since such gonococci have already been transferred to other parts of the U.K. Penicillinase-stable cephalosporins were active in vitro and could prove to be the future treatment of choice.

Cephalosporins↗
PubMed1968

Lifetime of messenger ribonucleic acid for penicillinase synthesis in several strains of bacilli.

1. Previous studies of penicillinase synthesis in Bacillus licheniformis showed that enzyme synthesis after the addition of actinomycin continues for far longer in the constitutive mutant 749/C than in the parental inducible strain (Yudkin, 1966). This result was interpreted as indicating a difference in the lifetime of specific messenger RNA in the two strains. Other bacilli have now been examined in an attempt to see whether this difference is general. 2. There was no difference in the lifetime of messenger RNA for penicillinase synthesis between an inducible and a constitutive strain of Bacillus cereus. 3. Three freshly isolated constitutive mutants of B. licheniformis also had short-lived messenger RNA, like their inducible parent. 4. A reinvestigation of mutant 749/C confirmed the original finding that, on treatment with actinomycin, it continued to synthesize penicillinase far longer than did its parent. 5. An inducible revertant of mutant 749/C was indistinguishable from the original inducible strain, and appeared to have lost both constitutivity and long-lived messenger RNA in the back mutation.

Bacillus↗
PubMed1989

Release of penicillinase by Escherichia coli HB101 (pEAP31) accompanying the simultaneous release of outer-membrane components by Kil peptide.

The plasmid pEAP31 contains an alkaliphilic-Bacillus penicillinase gene and a colicin E1 kil gene. Escherichia coli HB101 carrying pEAP31 grown at high temperature released outer-membrane proteins, lipopolysaccharide and phosphatidylethanolamine into the culture medium. Concurrently, penicillinase that had accumulated in the periplasm of the organism was released from the cells. Phospholipase A1-A2 in the outer membrane was not activated in the organism. The results suggest that the release of accumulated periplasmic penicillinase from the producer cells was caused by partial disruption of the outer membrane mediated by the Kil peptide.

Bacterial Outer Membrane Proteins↗
PubMed2003

Comparative studies with penicillinase, horseradish peroxidase, and alkaline phosphatase as enzyme labels in developing enzyme immunoassay of cortisol.

Relative merit of different enzyme labels for measuring cortisol directly in serum by competitive enzyme immunoassay (ELISA) was examined. Cortisol-21-hemisuccinate was labeled separately with penicillinase, horseradish peroxidase (HRP), and alkaline phosphatase (ALP) under identical reaction conditions. Antibody developed in rabbits against cortisol-3-0-(carboxymethyl)-oxime-bovine serum albumin was used to coat polystyrene tubes that were precoated with anti-rabbit gamma globulin (ARGG). Cortisol standards were prepared in steroid-free human serum in buffer (1:4) contaning 8-anilino-1-naphthalene sulfonic acid (8-ANS). Assay buffer also consisted 8-ANS. The assay involved adding standard cortisol or serum sample to antibody-coated tubes, followed by addition of enzyme label and buffer, and incubation for 2 h at 37 degrees C. The whole procedure took 3 h for completion. All three labels proved to be sensitive, with a slope around -2.0. Although penicillinase as an enzyme label was highly sensitive and stable compared with others, the assays were not always accurate and precise, especially at low concentrations of cortisol. This was mainly due to the color reagent used for measuring penicillinase activity. Serum samples that underwent 2-3 freeze-thaw cycles gave high values with HRP label compared with ALP. Therefore, utilizing ALP as an enzyme label, an ELISA was developed and its performance was comparable with some of the commercial kits already in the market.

Alkaline Phosphatase↗
PubMed1981

A rapid paper-disc test for penicillinase.

A practical acidimetric assay for penicillinase production using penicillin and phenol red impregnated in paper discs was developed. Blank discs were first impregnated with buffered penicillin G and, after drying, with 1% phenol red. For use, a disc was added to a bacterial suspension made in saline solution. A yellow color within 1 to 30 min of incubation indicated penicillinase production. These discs were tested against Staphylococcus aureus, Haemophilus influenzae, and Neisseria gonorrhoeae, and the assay was found to be a simple, rapid, and accurate method for detection of penicillinase.

Bacteria↗
PubMed1986

Penicillinase-producing Neisseria gonorrhoea as a cause of neonatal and adult ophthalmia.

A retrospective analysis of 80 cases of gonococcal ophthalmia revealed six (7.5%) to be due to penicillinase-producing Neisseria gonorrhoeae (PPNG), five neonatal cases and one adult. All six cases were finally cured, but best results were obtained with topical chloramphenicol and single-dose spectinomycin (40 mg/kg) given intramuscularly. All gonococcal isolates should be tested promptly for penicillinase production, and if this is present systemic treatment, modified to spectinomycin or penicillinase-stable cephalosporin, should be given as single-dose treatment.

Adult↗
PubMed1994

Cloning and expression of the penicillinase from a borderline methicillin-susceptible Staphylococcus aureus strain in Escherichia coli.

The blaZ gene contained in a single 17.2-kb beta-lactamase plasmid from a borderline methicillin-susceptible Staphylococcus aureus strain (a53) has been cloned in Escherichia coli. A Bluescript II derivative in which the ampicillin resistance gene has been replaced with the chloramphenicol resistance gene was used as a multi-copy vector. One ampicillin-resistant colony was detected among 31 chloramphenicol-resistant transformants selected. This E. coli clone harbored a recombinant plasmid (pAH12) containing two different staphylococcal HindIII inserts (7.0 and 5.3 kb), of which only the former hybridized with a blaZ probe. The clone showed an ampicillin MIC of > 1024 micrograms ml-1, independently of the inoculum size used, and produced large amounts of beta-lactamase, which hydrolyzed nitrocefin and penicillin G but not methicillin of the beta-lactamase substrate, padac. In contrast, S. aureus a53 hydrolyzed all four substrates. The fact that high levels of staphylococcal penicillinase are unable to cause methicillin hydrolysis confirms that penicillinase hyperproduction is unlikely to be the true mechanism responsible for the borderline phenotype. These results also suggest that the two different beta-lactamases (penicillinase and methicillinase) associated with borderline S. aureus strains have a different genetic origin.

Cloning, Molecular↗
PubMed1989

Evaluation of Stuart's transport medium containing penicillinase. An in vitro study. Brief report.

An in vitro study was performed to evaluate the value of penicillinase in Stuart's transport medium. Swabs were taken from serum broth cultures of Staphylococcus aureus, Escherichia coli and Proteus rettgeri, incubated with cefuroxime. Following 24 hours' storage in the transport medium, the recovery of P. rettgeri was significantly higher from Stuart's transport media containing penicillinase in a concentration of 100,000 units/ml, than from swabs stored in Stuart's medium without penicillinase. Although susceptible to cefuroxime, we did not find the same effect on S. aureus and E. coli, presumably because these strains had higher MIC values than the P. rettgeri strain tested.

Bacteria↗
PubMed1979

Comparative susceptibility of penicillinase-positive and -negative Neisseria gonorrhoeae to 30 antibiotics.

The minimal inhibitory concentrations of 30 antibiotics were determined by the agar dilution method for 17 penicillinase-positive and 50 penicillinase-negative strains of Neisseria gonorrhoeae. The latter included 42 strains that were penicillin susceptible (pen S) (minimal inhibitory concentration, <0.125 mug/ml) and 8 strains with intermediate resistance to penicillin (pen I; minimal inhibitory concentration, 0.125 to 0.5 mug/ml). Two penicillinase-resistant penicillins (methicillin and nafcillin) were inhibitory for penicillin-resistant (pen R) strains. Three new cephalosporins (cefuroxime, cefamandole, cefaclor) and a cephamycin (cefoxitin) were bacteriostatic (minimal inhibitory concentration </=0.8 mug/ml) for 90% of pen S, pen I, and pen R strains. Pen I strains were more resistant than pen R strains to 6 of 13 cephalosporins. Rifampin, erythromycin, spectinomycin, chloramphenicol, and the tetracyclines were inhibitory for both pen S and pen R strains. The minimal bactericidal concentrations of cefuroxime, cefamandole, cefaclor, and cefoxitin were measured for 17 pen R strains and eight pen I strains by serial dilution of the antibiotics in Trypticase soy broth supplemented with 1% Iso VitaleX and 1% hemoglobin. All tubes were subcultured after overnight incubation at 37 degrees C. Cefuroxime and cefoxitin were bactericidal at low concentrations (minimal bactericidal concentration, </=1.0 mug/ml) for 16 of 17 pen R strains and 6 of 8 pen I strains.

Anti-Bacterial Agents↗
PubMed1982

Properties of a new penicillinase type produced by Bacteroides fragilis.

A highly penicillin-resistant strain of Bacteroides fragilis, strain GN11499, was found among 80 clinical isolates of the B.fragilis group and appears to produce a new type of penicillinase. Penicillinase activity was detected in crude extracts and had a specific activity of 0.25 U/mg of protein. About 20% of the enzyme was released into the surrounding medium during growth. The enzyme hydrolyzed ampicillin and cloxacillin more rapidly than it did penicillin G, carbenicillin, and cephaloridine. Relative rates in a crude extract with penicillin G as 100 were ampicillin, 357; carbenicillin, 57; cloxacillin, 271; and cephaloridine, 71. Enzyme activity was inhibited by clavulanic acid, CP-45, 899, N-formimidoyl thienamycin, cefoxitin, moxalactam, and p-chloromercuribenzoate. The enzyme had a molecular weight of approximately 41,500 and an isoelectric point of 6.9. Penicillinase production and tetracycline resistance were transferred from B.fragilis GN11499 to two susceptible strains of B.fragilis and Bacteroides vulgatus by filter mating.

Bacterial Proteins↗
PubMed1973

Effect of the prophage and penicillinase plasmid of the recipient strain upon the transduction and the stability of methicillin resistance in Staphylococcus aureus.

Transduction of a methicillin-resistance determinant (mec) in Staphylococcus aureus RN450 was dependent on its prior lysogenization with an appropriate temperate phage. In addition, an appropriate transduced penicillinase plasmid was usually required. Some phage 80-resistant variants of RN450 or of its parental lysogenic strain, NCTC 8325, were also effective recipients for transduction of mec. Elimination of prophage from RN450 abrogated its effectiveness as a transductional recipient of mec. Elimination of prophage from a methicillin-resistant transductant of RN450 reduced resistance to undetectable levels in six of seven phage-eliminated strains. In four of these a variable number of clones again became phenotypically resistant after lysogenization alone or lysogenization combined with reintroduction of a penicillinase plasmid. In two prophage-eliminated strains, no evidence of residual mec could be adduced. The establishment, expression, or stability of the transduced mec in strain RN450 appeared to depend on some function determined by a prophage or a prophage and a penicillinase plasmid.

Chromosomes, Bacterial↗
PubMed1977

Vesicle penicillinase of Bacillus licheniformis: existence of periplasmic-releasing factor(s).

In earlier studies of the membrane-bound penicillinase of Bacillus licheniformis 749/C, the enzyme present in the vesicles that were released during protoplast formation and the enzyme retained in the plasma membrane of protoplasts appeared to differ (i) in their behavior on gel permeation chromatography in the presence or absence of deoxycholate and (ii) in their tendency to convert to the hydrophilic exoenzyme (Sargent and Lampen, 1970). We have now shown that these vesicle preparations contain a soluble, heat-sensitive enzyme(s) that is released along with the vesicles during protoplast formation. The enzyme will convert the vesicle penicillinase to a form that resembles exopenicillinase, and this conversion can be inhibited by deoxycholate under certain circumstances. Sedimentation of such vesicle preparations at 100,000 X g produces vesicles which contain penicillinase that behaves as the plasma membrane enzyme obtained from protoplasts. Exopenicillinases released by growing cells at pH 6.5 and by washed cells or protoplasts at pH 9.0 have the same NH2-terminal residues (lysine and some glutamic acid); in addition, the various release systems show a parallel sensitivity to inhibition by deoxycholate, quinacrine, chloroquine, and o-phenanthroline. The formation of exopenicillinase (by cleavage of the membrane-bound enzyme) may well be dependent on the action of the releasing enzyme.

Bacillus↗
PubMed1979

Immunoelectron microscopic localization of penicillinase in Bacillus licheniformis.

Penicillinase was localized in log-phase cells of Bacillus licheniformis 749/C by labeling with ferritin-anti-penicillinase immunoglobulin G conjugate. Mildly fixed homogenized cells, isolated subcellular fractions, and frozen thin sections were labeled. The label was distributed in discrete patches in the cell envelope. The patches extended from the inside part of the membrane to the outside part of the wall. The inside part of the membrane was labeled more extensively than the outside part. The cytoplasm also bound some ferritin-immunoglobulin G conjugate. Immunoelectrophoresis and biochemical assay of cytosol material suggest that the cytoplasmic antigenic sites are a protease-sensitive form of penicillinase.

Antigen-Antibody Reactions↗
PubMed1988

Regulation of the penicillinase genes of Bacillus licheniformis: interaction of the pen repressor with its operators.

The synthesis of the inducible enzyme penicillinase of Bacillus licheniformis is negatively controlled by a repressor (D.A. Dubnau and M.R. Pollock, J. Gen. Microbiol. 41:7-21, 1965; D. J. Sherratt and J. F. Collins, J. Gen. Microbiol. 76:217-230,1973). The molecular organization of the genes coding for penicillinase (penP) and its repressor (penI) has recently been determined (T. Himeno, T. Imanaka, and S. Aiba, J. Bacteriol. 168:1128-1132, 1986). These two genes are transcribed divergently from within a 364-nucleotide region separating the coding sequences. We cloned and sequenced the repressor gene (penIc) from strain 749/C that constitutively produces penicillinase. The penIc and penI+ (wild-type) genes were expressed in Escherichia coli. Complementation analysis indicated that the repressor is the only trans-acting protein required to regulate the expression of the penI and penP genes. We purified the wild-type repressor protein, used it in gel retardation and DNase I protection experiments, and identified three operators positioned in the region between the penP and penI coding sequences. The spatial arrangement of the operators and the hierarchy in repressor binding seen in the protection experiments indicate that (i) the penI gene product represses the expression of the penP gene by physically blocking the RNA polymerase-binding site and (ii) the penI gene is autoregulated.

Alleles↗
PubMed1962

Effect of pH and inorganic salts on penicillinase formation in Staphylococcus aureus.

Leitner, Felix (Michael Reese Hospital, Chicago, Ill.) and Sidney Cohen. Effect of pH and inorganic salts on penicillinase formation in Staphylococcus aureus. J. Bacteriol. 83:314-323. 1962.-Staphylococcus aureus strain 55-C-1 exhibited a progressive increase in penicillinase activity as the pH of its growth medium dropped from 6.0 to 4.7. At pH 4.7, the increase in enzymic activity was inhibited markedly by Ca(++), somewhat less by Mg(++), and moderately by NaCl, KCl, and NH(4)Cl. Inhibition by NaH(2)PO(4) was greater than by NaCl. Growth at the same pH, in small concentrations of Fe(NH(4))(2)(SO(4))(2) (10(-5) to 10(-6)m), elevated penicillinase activity strikingly, an effect shared to a lesser degree with FeCl(3), CoCl(2), and, very slightly, MnCl(2). The available evidence indicated that the changes in enzymic activity were the result of changes in rate of formation of the enzyme.

Culture Media↗
PubMed1966

Thermostability of Bacillus cereus penicillinase.

Williams, Daniel H., III (Hahnemann Medical College, Philadelphia, Pa.), A. Bondi, A. G. Moat, and F. Ahmad. Thermostability of Bacillus cereus penicillinase. J. Bacteriol. 91:257-261. 1966.-The extracellular penicillinase of Bacillus cereus, strain 13-10, exhibited an unusual thermostability. Whereas it was completely and irreversibly inactivated by heating at 70 C, it retained considerable activity when heated at 100 C for 30 min. The active enzyme remaining was completely stable to further heating at temperatures from 40 to 100 C for as long as 1 hr. Preparations of the enzyme heated to 100 C possessed pH (7.0) and temperature (37 C) optima identical with the unheated enzyme. Furthermore, both enzyme preparations exhibited identical combining capacity for the substrate (penicillin G), suggesting that the two preparations had similar hydrolytic properties. Our findings suggest that heating of penicillinase at 100 C results in the formation of a protein complex which is resistant to further denaturation by heat and other agents. Addition of certain metal ions to the enzyme solution before heat treatment increased the stability to heat at 100 C by virtue of their ability to induce complex formation. Pectin was shown to decrease thermostability, presumably by preventing aggregation of proteins present in the enzyme preparations. The well-known stabilizing effect of gelatin may be attributed to its role in enhancing complex formation.

Bacillus cereus↗
PubMed1968

Morphological phenomena associated with penicillinase induction and secretion in Bacillus licheniformis.

Cells of uninduced Bacillus licheniformis (strain 749) in mid-logarithmic phase have no extensive intracytoplasmic membrane. After induction with cephalosporin C, characteristic organelles that contain tubules and vesicles with single-layered membranes and no visible internal substructure can be seen in thin sections in the periplasm. A magnoconstitutive penicillinase producer (749/C) contains similar structures. It is suggested that they represent a penicillinase secretory apparatus. In the first 15 min after induction, negatively stained preparations of induced 749 show large intracellular vesicles without individual contact with the cell surface. Negatively stained 749/C and fully induced 749 contain invaginations comparable to the structures seen in thin sections. When protoplasts of induced 749 and of 749/C are prepared, vesicles and tubules similar to those seen in thin sections of whole cells are liberated from the cell. Growing protoplasts of induced 749 show massive convolutions of the peripheral membrane, multiple layers of membrane, and characteristic long, slender tubules extending from the protoplast surface. These phenomena are not observed in uninduced 749 except for the production of a relatively small number of tubules. In 749/C, there were fewer convolutions than in induced 749, although tubule production was similar. Multiple layers of membrane were not observed in 749/C. The relation of the penicillinase secretory structures to mesosomes and to secretory structures of other organisms is discussed.

Bacillus↗