Chromosomally mediated intrinsic resistance to penicillin of penicillinase producing strains of Neisseria gonorrhoeae isolated in Sydney: guide to treatment with Augmentin

Single dose Augmentin treatment fails to cure an appreciable proportion of patients infected with penicillinase producing Neisseria gonorrhoeae (PPNG) strains in parts of the world where high levels of chromosomally mediated intrinsic resistance are also present in gonococci. The levels of intrinsic resistance to penicillin of 31 PPNG strains isolated in Sydney were assessed by obtaining beta lactamase negative variants of these strains and measuring the minimum inhibitory concentration of penicillin by agar plate dilution techniques. The levels of intrinsic resistance found in these imported PPNG strains were higher than those recorded for local isolates of non-PPNG strains, which indicates that caution should be exercised in the use of single dose Augmentin treatment of infections with PPNG strains in Sydney.

Susceptibility of Neisseria gonorrhoeae to pefloxacin

144 strains each of penicillinase producing (PPNG) and non-penicillinase producing (NPPNG) Neisseria gonorrhoeae were tested for susceptibility to pefloxacin. All isolates but one (99.65%) were susceptible to 0.06 mg/l. No significant difference was detected between the minimum inhibitory concentrations (MICs) of PPNG and NPPNG strains. The MIC50 and MIC90 of both types of strains were 0.015 mg/l and 0.06 mg/l respectively. Since pefloxacin was more effective than norfloxacin and rosoxacin against PPNG as well as NPPNG, it should prove useful in the therapy of gonorrhoea.

Analysis of penicillinase-producing Neisseria gonorrhoeae isolates in Madrid (Spain) from 1983-85

Between April 1983 and December 1985, 576 strains of Neisseria gonorrhoeae were isolated in our laboratory from patients attending Sexually Transmitted Diseases (STD) clinics. Of these, 61 (10.6%) were penicillinase-producing. Studies on these strains by plasmid analysis, auxotyping and serogrouping showed that the predominant type strains harboured the Asian resistance plasmid, were prototrophic, and were of serogroup W II/W III. About half of the strains, both of the African and Asian type, harboured the transfer plasmid. Strains of serogroup W II/W III were less sensitive to tetracycline and cefoxitin than serogroup W I strains.

Auxotypes, plasmid contents, and serovars of gonococcal strains (PPNG and non-PPNG) from Jamaica

The analysis of the auxotypes and plasmid profiles of 459 non-PPNG strains from Jamaica suggests that strains have been imported to the island. Unlike in many developing countries where strains are differentiated by only a few auxotypes, 13 different auxotypes were identified in the non-PPNG strains. In Jamaica over 10% of the strains were plasmid free and required proline, citrulline, and uracil (PCU-) for growth. These isolates predominate in Canada and are increasingly reported from areas of the United States of America and Europe. The serological analysis of 168 of the non-PPNG strains indicated that most (76%, 128) were from serogroup WII/III. Serogroup WII/III strains comprised 17 serovar combinations with GS and Ph reagents, whereas serogroup WI strains included only four serovars. Unusually, most WI Aedgkih non-PPNG strains were wild type or proline requiring. Strains of serovar Aedg were especially noted (in 93%, 13/14) for carriage of the transfer plasmid. The first 20 PPNG strains isolated in Jamaica proved to have multiple origins as they had eight variations of auxotype, serovar, and plasmid content. Most (60%, 12/20) of those isolated were typed as serogroup WI, and 10 of these isolates were serovar Aedgkih. Although most (70%, 14/20) PPNG strains harboured African type plasmids with or without transfer plasmids, six also carried Asian type plasmids (with the transfer plasmid).

Effect of spectinomycin use on the prevalence of spectinomycin-resistant and of penicillinase-producing Neisseria gonorrhoeae

Because of the high prevalence of penicillinase-producing Neisseria gonorrhoeae in the Republic of Korea, spectinomycin has been used there in the primary treatment of gonococcal infections in U.S. military personnel since 1981, but there have been increasingly frequent reports of treatment failures with spectinomycin. We conducted a clinical study to determine the efficacy of spectinomycin treatment in 124 U.S. servicemen in the Republic of Korea who had urethral gonococcal infections. Ninety-seven patients were treated with spectinomycin alone and evaluated in a follow-up visit. In eight patients (8.2 percent), this treatment was unsuccessful. Antibiotic-sensitivity testing on isolates from seven of the patients with treatment failure demonstrated that six isolates were highly resistant to spectinomycin (minimal inhibitory concentration, greater than or equal to 100 micrograms per milliliter). None of the spectinomycin-resistant strains had become resistant to penicillin, either through the production of penicillinase or through a chromosomal mutation. Although the mechanism of spectinomycin resistance appears to be a chromosomal mutation, these isolates were generally sensitive to other antibiotics. The prevalence of resistance to spectinomycin resulted in the substitution of ceftriaxone for the primary treatment of gonorrhea acquired by U.S. military personnel in the Republic of Korea. We believe that the rapid emergence of spectinomycin resistance in this population mandates a cautious approach to widescale use of the drug and indicates a need to broaden current surveillance programs.

Molecular cloning and sequencing of a cDNA encoding the acyl carrier protein and its flanking domains in the mammalian fatty acid synthetase

Cloned cDNAs containing coding sequences for domains proximal to the carboxy terminus of the rat fatty acid synthetase have been isolated using an expression vector and domain-specific antibodies. The coding regions were assigned to specific domains of the multifunctional complex by identification of sequences coding for characterized peptide fragments and by recognition of sequences homologous to other monofunctional enzymes. Two clones contain the entire coding region for the acyl carrier protein domain. The sequence is flanked at the 3'-end by a region coding for the thioesterase domain and at the 5'-end by a sequence coding for a reductase, most likely the ketoreductase domain. Thus the ordering of these domain-coding regions in the fatty acid synthetase mRNA is established. The acyl carrier protein domain exhibits about 25% homology with that of the discrete monofunctional acyl carrier proteins of Escherichia coli, spinach and barley, the ketoreductase domain exhibits about 25% homology with bacterial dihydrofolate reductases and the active site of the thioesterase domain exhibits both primary and secondary structural features common to the serine proteases. These findings lend support to the hypothesis that the polyfunctional fatty acid synthetase probably arose by a complex evolutionary process involving fusion of genes coding for seven individual enzymes.

Serological ecology of Neisseria gonorrhoeae (PPNG and non-PPNG) strains: Canadian perspective

One hundred and thirty eight penicillinase producing Neisseria gonorrhoeae (PPNG) and 239 non-PPNG strains were characterised serologically using a panel of seven monoclonal antibodies directed against protein 1A and seven against protein 1B. An association between serovar and susceptibility to antimicrobial agents, auxotype, and plasmid content was observed. Serogroup WI strains were more sensitive to penicillin, ampicillin, tetracycline, erythromycin, cefoxitin, and cefuroxime. Sixty five (82%) of the 79 WI strains were typed as being serovar Aedgkih, and 47 (72%) of these strains required arginine, uracil, and hypoxanthine for growth (AUH-). Seventy one (44%) of 160 WII/WIII strains were serovar Bacejk, and 42 (59%) of these required proline, citrulline, and uracil for growth (PCU-) and were plasmid free. Serovars Bcgk, Beghjk, Bacjk, and Bajk were associated with resistance to antimicrobial agents. Analysis of PPNG isolates showed a new serovar, Af, which was associated with strains imported from Malaysia and Singapore that required proline and ornithine for growth (Pro-Orn-) and carried the 24.5 megadalton transfer plasmid, the 2.6 megadalton cryptic plasmid, and the 4.5 megadalton penicillinase producing plasmid. Other associations between serovar and geographical location were noted.

Serovars, auxotypes, and plasmid contents of PPNG strains from outbreak in Amsterdam

The first outbreak of penicillinase producing strains of Neisseria gonorrhoeae (PPNG) in Amsterdam in 1981-2 was caused mainly by African strains carrying the 24 megadalton transfer plasmid (Afr+) that were non-requiring (NR) and inhibited by phenylalanine (pheni), but African strains without the transfer plasmid (Afr-) that were NRpheni and Afr+ NR strains were also found. Serological classification, using two monoclonal antibody systems, showed that three main serovars (Ae/Av, Aedih/Arst, and Bacejk/Brpyust) could be distinguished in these PPNG strains, which indicated exchanges of plasmids in these serovars. The serovar Ae/Av predominated in the Afr+ and Bacejk/Brpyust in the Afr- strains.

[Characteristics of penicillinase-producing strains of Neisseria gonorrhoeae isolated in France, 1979-1986]

Penicillinase producing Neisseria gonorrhoeae PPNG, had been first isolated in France in 1979. Since, they regularly increased if we considered France on the whole. From 1979 to 1986, 284 strains had been collected by a multicentric group. The frequency of isolation was strongly different in France, unknown in some region they rose 12% in specific areas in Paris. The PPNG strains were more frequently isolated from male than female (sex ratio was higher with PPNG than for non producing strain). They were more often responsible of complicated infections in female than male at the same rate than the non producing strains. Auxotype distribution was different between producing and non producing strains. Plasmidic content from african type (Af) was almost the same than from asian type (As). Strains with Af type associated with the conjugative plasmid were increasing.

Indication of thioglucosidase activity in extracts of Neisseria gonorrhoeae

The recent demonstration of a host-derived inducer of gonococcal resistance to complement-mediated killing by human serum in purified serum and red blood cell fractions, which contained small glucopeptides with cysteine as one of the constituent amino acids, prompted an investigation of Neisseria gonorrhoeae for thioglucosidase activity. This involved an examination of supernatants of sonicated gonococci for thioglucoside hydrolysis by following, spectroscopically, the hydrolysis of 6-purine beta-D-glucothiopyranoside to 6-mercaptopurine and glucose. Extracts of N. gonorrhoeae were found to hydrolyse this thioglucoside. A substantial activity was present in a fraction with the same order of molecular weight as plant thioglucosidases. This led us to suspect the presence of a thioglucosidase in N. gonorrhoeae.

Infections due to beta-lactamase-producing Neisseria gonorrhoeae at the University Hospital Medical Center, Kuala Lumpur, Malaysia

The incidence of infections due to beta-lactamase-producing Neisseria gonorrhoeae is increasing in many parts of the world. An epidemiologic survey of infections caused by beta-lactamase-producing strains of N. gonorrhoeae at the University Hospital, Kuala Lumpur, from February 1977 to December 1985 (106 months) showed that the incidence rose from 4.8% (two cases) in 1977 to 49.4% (39 cases) by the end of 1985. The highest incidence of gonococcal infections was found to be in the group aged 20-39 years; the male-to-female ratio was 1.55:1. The mean inhibitory concentrations of benzylpenicillin were 0.12 microgram/ml for non-beta-lactamase-producing strains and 16 micrograms/ml for isolates of N. gonorrhoeae that produce beta-lactamase.

Comparative in-vitro activity of enoxacin against penicillinase- and non-penicillinase-producing Neisseria gonorrhoeae

The in-vitro antigonococcal activity of enoxacin was measured by a broth microdilution method. Comparisons were made with five clinically relevant marketed drugs against 23 clinical isolates of Neisseria gonorrhoeae, including several penicillinase producers as well as multiply resistant strains. Results showed that enoxacin possessed potent activity against all organisms tested, with MIC values ranging from less than or equal to 0.013 to 0.05 micrograms/ml.

Immunoglobulin A1 protease types of Neisseria gonorrhoeae and their relationship to auxotype and serovar

Immunoglobulin A1 (IgA1) proteases are extracellular bacterial proteolytic enzymes which correlate with virulence in several species of human pathogens. We report that Neisseria gonorrhoeae produced two distinct types of IgA1 protease, each of which cleaved a different peptide bond in the hinge region of human IgA1. The type of IgA1 protease produced correlated with both nutritional auxotype and outer membrane protein I serovar in this organism. Gonococcal type 1 IgA1 protease was produced primarily by N. gonorrhoeae strains which require arginine, hypoxanthine, and uracil (AHU) and which belong to the protein IA-1 or IA-2 serovar. Most isolates of other auxotypes and serovars produced type 2 IgA1 protease. Although both the AHU auxotype and protein IA serogroup were found to be associated with disseminated gonococcal infection, there was no direct correlation of IgA1 protease type with disseminated or with uncomplicated gonorrhea.

Single-dose antibiotic therapy for the treatment of uncomplicated anogenital gonorrhoea

Appropriate single-dose therapy will cure in excess of 95% of cases of uncomplicated anogenital gonorrhoea. Changes in the susceptibility of local isolates of Neisseria gonorrhoeae, particularly the emergence of beta-lactamase producing (and therefore penicillin-resistant) strains, have necessitated the modification of standard treatment regimens. Different patterns of antibiotic resistance have been documented in different regions of Australia and therapeutic regimens that are appropriate for use in different regions are recommended.