Auxotypes and antibiotic susceptibility patterns of Neisseria gonorrhoeae from disseminated and local infections

Strain characteristics and antibiotic susceptibility of isolates of Neisseria gonorrhoeae causing disseminated gonococcal infection in Australia. Members of the Australian Gonococcal Surveillance Programme

The auxotype (A) and serovar (S) distribution and antibiotic and serum sensitivity of 22 strains of Neisseria gonorrhoeae isolated from blood and joints were determined. With one exception, these strains from disseminated gonococcal infections (DGI) belonged to one of 4 serovars of the IA serogroup and were resistant to killing by normal human serum. The auxotype distribution of these Australian strains differed significantly from that reported elsewhere in that 17 of the 22 isolates were proline requires, but none were of the AHU auxotype. This lack of the AHU auxotype in the DGI strains in Australia was explained by the virtual absence of AHU requirers in a sample of 1560 mucosal strains isolated in Sydney and Darwin from 1987 to 1990. The A/S distribution of these mucosal isolates also helped to account for the low (0.12) percentage of DGI strains in isolates examined by the Australian Gonococcal Surveillance Programme (AGSP) from 1981 to 1991, and the differences in the rates of DGI in Sydney (0.08%) and Darwin (0.87%). There was a relative lack of the IA serogroup strains which are mostly responsible for DGI in the mucosal isolates from Sydney (15% of all strains) but a higher proportion of these serovars (40%) in the Darwin sample. There were 46 cases of DGI in data from the AGSP, 29 of these being women. Seven of the cases diagnosed in Australia were infected with penicillinase-producing gonococci suggesting that antibiotics other than the penicillins should now be used for this condition in this region.

Epidemiological studies on Neisseria gonorrhoeae isolated in the United Kingdom

Seven hundred and seventy nine isolates of Neisseria gonorrhoeae from the County of Avon, United Kingdom, were examined by auxotyping and penicillin susceptibility testing. Prototrophic strains which were heterogeneous as judge by penicillin susceptibility were the most commonly isolated and increased in prevalence over the three year period. The group most generally susceptible to penicillin required ArgHypUra for growth and decreased in prevalence over the three year period. Ten strains failed to grow on the auxotyping medium. Serogrouping was undertaken on 408 isolates. All strains reacting with the WI reagents were ArgHypUra requiring. However auxotypically similar strains (ArgHypUra) reacted with WII/WIII reagents suggesting a distinct and separately evolved group. Twenty four strains did not type with the serogrouping reagents. Using contact pairs, W-class serology was found to be a stable marker during natural transmission. However auxotypes were found to be unstable in 22 of 104 contact pairs and of these 18 involved a single requirement for proline. This very high incidence of instability with respect to this marker means it is not possible to reliably differentiate between the prototrophic group and the group with a single requirement for proline.

Antibiotic susceptibilities and auxotypes of Neisseria gonorrhoeae strains from women with pelvic inflammatory disease or uncomplicated infections

The purpose of the present study was to compare the auxotypes and the minimal inhibitory concentrations of four antibiotics for 50 isolates from women with gonococcal pelvic inflammatory disease with those of 55 isolates from uncomplicated anogenital gonococcal infections. No significant differences in auxotype patterns and susceptibilities were found between isolates from the two groups.

Epidemiology of gonorrhoea: serogroup, antibiotic susceptibility and auxotype patterns of consecutive gonococcal isolates from ten different areas of Sweden

Consecutively isolated gonococcal strains from 10 representative geographical areas in Sweden were serogrouped according to the previously described W antigen class. The majority of the strains were antibiotic susceptibility tested and approximately one fourth of them were auxotyped. Statistically significant differences of the serogroup patterns were demonstrated between the 2 largest towns, which represented highly urbanized areas where serogroup W II dominated, and the middle sized towns with adjoining rural districts, where serogroup W I dominated. The serogroup patterns of the strains isolated in 3 university towns were representative for Sweden as a whole. Statistically significant differences were demonstrated between urban and rural areas with regard to the susceptibility of gonococci to beta-lactam antibiotics. About 95% of serogroup W I strains were highly sensitive to ampicillin whereas about 65% and 90% of W II and W III strains, respectively, showed decreased susceptibility. The majority of the auxotyped strains belonged to 4 main types: Pro-, Pro-Arg-Ura-, AHU- and prototrophic. The majority of the AHU- strains belonged to serogroup W I and were highly susceptible to beta-lactam antibiotics and tetracycline. Many of the Pro-Arg-Ura-strains belonged to 2 particular subserogroups within serogroup W II and showed increased resistance to beta-lactam antibiotics. Serological classification of gonococci by co-agglutination is a simple and rapid technique without need of special equipment. It could serve 2 purposes: 1) as a confirmation test for gonococci cultured from clinical specimens; 2) for serogrouping of gonococcal isolates to study the epidemiology of gonorrhoea with regard to geographical areas, race, sexual preference, treatment failure and other demographic and medical factors.

Neisseria gonorrhoeae isolated from disseminated and localised infections in pre-penicillin era. Auxotypes and antibacterial drug resistances

Interest in the evolution of gonococcal auxotrophy led to a study of 72 strains isolated between 1935 and 1948 from the urogenital tract (57 patients), the eye (two patients), and from disseminated gonococcal infections (11 patients and probably two others). Two cervical isolates with nutritional requirements for proline, arginine, histidine, and biotin were oxidase-positive, Gram-negative diplococci, but their identity as Neisseria gonorrhoeae was uncertain because they were atypically susceptible to colistin and did not produce acid in glucose media. The N gonorrhoeae strains were highly susceptible to 11 other antibacterial drugs but not to sulphadiazine. Defects of one or more pathways for the biosynthesis of methionine, proline, arginine, threonine, lysine, the branched-chain amino acids, hypoxanthine, and thiamine pyrophosphate were found in 39 of the 70 strains, including four isolated in the presulphanilamide era. Unexpectedly, methionine was required for the growth of 11 (21%) of the 52 Danish strains and for 13 (72%) of 18 strains isolated in the USA. The Danish strains included 28 (54%) that did not require any of the compounds used for differentiating auxotypes, whereas this type was represented by only three (17%) of the USA strains. None of the gonococci required uracil or other pyrimidines. This suggests that the requirements for arginine, hypoxanthine, and uracil commonly found in recent isolates from disseminated gonococcal infections probably evolved treatment with sulphonamide was replaced by penicillin.

Inhibition of Neisseria gonorrhoeae isolates by Martin-Lewis medium. Epidemiology, susceptibility profile, and plasma analysis

A study was undertaken on the premise that if an increase of 1 microgram/ml in the concentration of vancomycin in Martin-Lewis medium (MLM) could improve inhibition of Gram-positive cocci, then a concomitant increase in the inhibition of gonococci could also occur. Isolates of Neisseria gonorrhoeae that failed to grow on MLM accounted for 18-5% of all positive culture results for gonorrhoea. The incidence of isolates susceptible to vancomycin was 14% and of those susceptible to trimethoprim 2.4%; one isolate was susceptible to both vancomycin and trimethoprim. The antibiotic-susceptible isolates were more frequently isolated from asymptomatic white men. Plasmid analysis showed that the 2.4-megadalton cryptic plasmic was absent in the vancomycin-susceptible isolates. The large proportion of isolates failing to grow on selective MLM has important clinical implications for the diagnosis of gonorrhea.

Serology of Neisseria gonorrhoeae: W-antigen serogrouping by coagglutination and protein I serotyping by enzyme-linked immunosorbent assay both detect protein I antigens

A total of 224 strains were serogrouped by coagglutination (COA) and serotyped by protein I enzyme-linked immunosorbent assay (ELISA). Of these strains, 61 were from patients with disseminated gonococcal infection, 21 were from patients with pelvic inflammatory disease, and 115 were from patients with uncomplicated gonococcal infection in Singapore, the Philippines, and Denmark. Twenty-seven were laboratory reference strains. Of the patient strains, 102 belonged to COA serogroup WI, and all of the 100 strains that typed with protein I serotypes 1, 2, or 3 were in this group. Most of the strains of gonococci from the 61 patients with disseminated gonococcal infection were within this group (COA WI, 53 or 87%; protein I serotypes 1, 2, or 3, 51 or 84%). All 46 strains that were protein I serotypes 4 through 7 were also COA serogroup WII. Protein I serotypes 8 and 9 accounted for 49 (25%) of the 197 patient strains. Twenty-eight of these strains typed as COA serogroup WII, 20 typed as serogroup WIII, and 1 typed as serogroups WII and WIII. COA W serogrouping and protein I ELISA both appeared to detect antigens on the protein I molecule of the outer membrane of Neisseria gonorrhoeae. Protein I serotyping, which uses unboiled organisms, may generally recognize more variable and surface-exposed antigenic determinants. In contrast, COA W serogrouping, which uses boiled organisms, may recognize less exposed shared antigenic determinants in addition to variable protein I antigenic determinants. Both methods may prove useful for further studies of the epidemiology and pathogenesis of gonorrhea.

Neisseria gonorrhoeae strains inhibited by vancomycin in selective media and correlation with auxotype

Strains of Neisseria gonorrhoeae that failed to grow on Thayer-Martin (T-M) and Martin-Lewis (M-L) media accounted for 2.0% of isolates at the University of Colorado Hospital and its Venereal Disease Clinic. A total of 31 inhibited and 31 control strains were compared by agar dilution testing for their susceptibilities to 13 antimicrobial agents used for treatment or in selective media. All 62 isolates were resistant to lincomycin, colistin, nystatin, amphotericin B, trimethoprim lactate, polymyxin B, and anisomycin. Vancomycin was the inhibitory antibiotic for N. gonorrhoeae in both T-M and M-L media. The vancomycin-inhibited strains were also significantly more sensitive to penicillin and ampicillin than were the control strains (P less than 0.001). The presence of the other antibiotics in selective media did not affect the minimum inhibitory concentrations of vancomycin for gonococci. All 31 inhibited strains were sensitive to 8.0 micrograms of vancomycin per ml, and 26 of these were sensitive to 2.0 microgram/ml. Decreasing the size of inoculum of gonococci results in greater inhibition by any given concentration of vancomycin. The vancomycin-sensitive strains contained significantly more arginine- hypoxanthine-, and uracil-requiring auxotypes (28 out of 31) than did the control strains (9 out of 31). As with T-M medium, some strains of gonococci will be missed when M-L medium with 4.0 micrograms of vancomycin per ml is the only medium used for the diagnosis of gonorrhea. This may be of particular importance in the confirmation of disseminated infection with Arg- Hyx- Ura- auxotypes of N. gonorrhoeae when cultures of blood, joint fluid, or skin lesions are negative.

Comparison of virulence markers of peritoneal and fallopian tube isolates with endocervical Neisseria gonorrhoeae isolates from women with acute salpingitis

Neisseria gonorrhoeae strains which cause acute salpingitis are presumed to ascend the genital tract from the cervix. Previous studies utilized isolates obtained from endocervical canal cultures, although it was not known if the isolates truly represented the organisms present in the fallopian tubes. In this study, we compared N. gonorrhoeae isolates from endocervical canal cultures with fallopian tube or peritoneal cul-de-sac isolates or isolates from both sites obtained at laparoscopy. Potential virulence markers were studied, including colony phenotype, auxotype, antimicrobial agent susceptibility, protein patterns on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and susceptibility to normal human serum. Six of seven cervical isolates had the same antibiograms and molecular weight for major outer membrane proteins as those of the corresponding peritoneal isolates. Auxotypes also were the same and included prototrophic, proline-requiring, and proline-and-arginine-requiring isolates. The isolates as a group appeared to be very susceptible to the bactericidal action of pooled serum from normal women. Colony phenotypes varied between sites; the fallopian tubecul-de-sac isolates were predominantly of transparent phenotype and piliated. The cervical isolates were either mixtures of equal quantities of opaque and transparent phenotypes or predominantly opaque phenotype. By these markers, patients' N. gonorrhoeae cervical isolates appeared to be the same as their isolates from fallopian tubes except for a difference or shift in colony phenotype.

The microbiology and therapy of acute pelvic inflammatory disease in hospitalized patients

We examined microbial isolates from the endocervical and peritoneal cavity of 30 women hospitalized with acute PID. Patients were randomly assigned to one of two antibiotic regimens: amoxicillin, 6 gm by mouth every 24 hours, or aqueous penicillin G, 30 million units and gentamicin, 180 to 240 mg intravenously every 24 hours. We measured response by quantifying physical examination findings. Neisseria gonorrhoeae was isolated from the cervix of 24 patients (80%) and from the peritoneal cavity of 10 (33%). Other peritoneal isolates included Enterobacteriaceae in five patients, Ureaplasma urealyticum in five, Mycoplasma hominis in six, and Chlamydia trachomatis in three. Bacteroides melaninogenicus, the most frequent anaerobe, was isolated in 11 cases. Bacteroides fragillis was not isolated from any specimen. The cure rates were the same for both regimens: three patients failed on each. Four women required total abdominal hysterectomy and unilateral or bilateral salpingo-oophorectomy.