Gonococcal Susceptibility Research Articles

Modulation of Neisseria gonorrhoeae susceptibility to vertebrate antibacterial peptides due to a member of the resistance/nodulation/division efflux pump family.

We have previously described the antibacterial capacity of protegrin-1 (PG-1), a cysteine-rich, cationic peptide from porcine leukocytes, against Neisseria gonorrhoeae. We now report genetic and biochemical evidence that gonococcal susceptibility to the lethal action of PG-1 and other structurally unrelated antibacterial peptides, including a peptide (LL-37) that is expressed constitutively by human granulocytes and testis and inducibly by keratinocytes, is modulated by an energy-dependent efflux system termed mtr. These results indicate that such efflux systems may enable mucosal pathogens like gonococci to resist endogenous antimicrobial peptides that are thought to act during infection.

Gonococcal susceptibility to antimicrobials in Baltimore, 1988-1994. What was the impact of ciprofloxacin as first-line therapy for gonorrhea?

Single-dose, oral quinolones have been a recommended treatment option for gonorrhea since 1989 and have since been used as first-line therapy for gonorrhea in Baltimore. The impact of this strategy on antimicobial susceptibility patterns in Neisseria gonorrhoeae was assessed utilizing data collected as part of the National Gonococcal Isolate Surveillance system. This system evaluates a systematically collected sample. Minimum inhibitory concentrations to penicillin, tetracycline, ceftriaxone, and ciprofloxacin were determined by agar dilution. Between January 1988 and September 1994, 1,846 gonococcal isolates were evaluated. The proportion of isolates with plasmid-mediated resistance (penicillinase-producing Neisseria gonorrhoeae or tetracycline-resistant Neisseria gonorrhoeae) increased from 22% in 1988 to 46% in 1992 and then dropped to 20% in 1994. In contrast, the prevalence of chromosomally mediated resistant isolates ranged between 3% and 10%. Between 1988 and 1994, the geometric mean penicillin and tetracycline minimum inhibitory concentrations decreased slightly (penicillin: from 0.509 microgram/ml to 0.369 microgram/ml; tetracycline: from 1.01 micrograms/ml to 0.767 microgram/ml). The mean ceftriaxone MIC increased from 0.005 microgram/ml in 1988 to 0.021 microgram/ml in 1992, and then abruptly decreased. Ciprofloxacin minimum inhibitory concentrations did not change substantially during the study period. Concurrent studies performed in this community suggest that quinolones were infrequently used for infections other than sexually transmitted ones during this time period. Single-dose quinolone therapy does not appear to foster development of resistant gonococcal isolates. However, resistance may develop as a result of complex ecological interactions with the community, underscoring the need for continued surveillance.

Interpretive criteria for susceptibility tests with DU-6859a and FK-037 tested against Haemophilus influenzae and Neisseria gonorrhoeae

Preliminary susceptibility testing interpretive criteria were determined for two investigational drugs, DU-6859a and FK-037, when tested against Haemophilus influenzae and Neisseria gonorrhoeae strains. National Committee for Clinical Laboratory Standards (NCCLS) methods with the Haemophilus Test Medium and GC agar base were utilized, and the study design conformed to the NCCLS M23-A guidelines. The proposed H. influenzae susceptibility testing criteria were for DU-6859a susceptible at ⩽1 μg/ml (5-μg disk zone diameter correlate, ⩾19 mm) or ⩽2 μg/ml (disk zone diameter correlate, ⩾16 mm) and for FK-037 susceptible at ⩽2 μg/ml (30-μg disk zone diameter correlate, ⩾19 mm). No other susceptibility categories were proposed. The gonococcal susceptibility testing criteria were for DU-6859a susceptible at ⩽0.12 μg/ml (disk zone diameter correlate, ⩾34 mm) and for FK-037 susceptible at ⩽0.5 μg/ml (disk zone diameter correlate, ⩾30 mm) and resistant at >1 μg/ml (disk zone diameter correlate, ⩽26 mm). No resistant criterion was proposed for N. gonorrhoeae tests with DU-6859a. No interpretive discrepancies were observed between methods using these proposed testing criteria.

The incidence of gonorrhoea and the antibiotic sensitivity of gonococci in Australia, 1981-1991. The Australian Gonococcal Surveillance Programme.

To review and analyse the changing incidence of gonorrhoea and the increasing antibiotic resistance in gonococci in Australia from 1981 to 1991. Use of data from the sample of gonorrhoea in Australia examined by the Australian Gonococcal Surveillance Programme (AGSP), a continuing long-term multi-centric study of gonococcal disease and gonococcal susceptibility to antibiotics, over the period 1 July, 1981 to 30 June, 1991. Over 32,000 cases and strains from defined sources were examined in the 10 year study period. The number of cases of gonorrhoea in the sample decline from a peak of 6599 in 1982-1983 to 1121 in the final year under review, a reduction of 83%. Periods when greater than average reductions in incidence occurred in different groups were noted. Ano-rectal gonorrhoea in men decreased sharply in 1985 during an overall decline of 92.5% recorded between 1 July, 1981 to 30 June, 1987. However, the incidence of ano-rectal cases in males rose in subsequent years while gonorrhoea, overall, continued to decrease and at a greater rate after 1985. Antibiotic resistance in gonococci in Australia was manifested both as a progressive increase in the levels of intrinsic resistance to the penicillins and through the appearance and spread of penicillinase-producing N gonorrhoeae (PPNG). At the end of the review period in June, 1991, 8.8% of gonococcal isolates in Australia showed high levels of intrinsic resistance to the penicillins and 13% of strains were PPNG. These separate mechanisms of resistance appeared at different times in different parts of Australia, and their importance also varied throughout the country. Most infections with PPNG were acquired by men overseas whereas most women with PPNG were infected locally. Endemic spread of PPNG was a significant problem in Sydney and Melbourne, but decreased in importance in the later years of the study. In the past decade a large reduction in the incidence of gonorrhoea and, by implication, other STDs has occurred in the past decade in Australia. In some groups of patients the decline in incidence is continuing while in others a slight increase has been noted. Resistance to antibiotics of gonococci in Australia was mainly restricted to the penicillins, but through both chromosomal and plasmid-mediated mechanisms. This resistance was seen particularly in Sydney and Melbourne where endemic cycles of transmission of PPNG were established, and in infected travellers from S-E Asia in other centres. Valid and comparable, and regionally relevant data are a continuing requirement for assessing and modifying antibiotic treatment regimens for gonococcal disease.

Molecular mechanism for the antigonococcal action of lysosomal cathepsin G

Human lysosomal cathepsin G (cat G) appears to be an important mediator of non-oxidative killing of Neisseria gonorrhoeae ingested by human polymorphonuclear leucocytes (PMNLs). Nearly isogenic strains of gonococci having variations in the structure of penicillin-binding protein 2 (PBP2) also exhibit different levels of susceptibility to the lethal action of cat G in vitro. Accordingly, we examined the relationship between gonococcal susceptibility to cat G and PBP2 structure. The results of this study suggest that cat G has the capacity to interact with PBP2, as evidenced by its ability to inhibit binding of [3H]-benzylpenicillin to PBP2. We also found that changes in the amino acid sequence within the transpeptidase domain of PBP2, because of certain penA mutations, modulated such interactions. We propose that PBP2 is an intracellular target for cat G and that levels of gonococcal susceptibility to cat G may be related to PBP2 structure and/or intracellular availability.

Standardization of disk diffusion and agar dilution susceptibility tests for Neisseria gonorrhoeae: interpretive criteria and quality control guidelines for ceftriaxone, penicillin, spectinomycin, and tetracycline

A six-laboratory study developed a standardized method for determining the susceptibilities of Neisseria gonorrhoeae strains to penicillin, tetracycline, spectinomycin, and ceftriaxone. Three quality control organisms were also selected, and quality assurance guidelines were initially generated for the disk diffusion and agar dilution methods. The medium recommended for gonococcal susceptibility testing was GC agar with a defined "XV-like" supplement. The supplement should be free of cysteine, a component implicated in the inactivation of some newer beta-lactam compounds. Penicillin, tetracycline, spectinomycin, and ceftriaxone were stable in agar plates stored at 3 to 5 degrees C for at least 2 weeks. Numerous GC agar and drug disk lots were used during the trials without significant variation in test results. Several other gonococcal strains were recommended for additional medium quality assurance. The disk quality control zone limits were established for N. gonorrhoeae ATCC 49226 (formerly CDC F-18) and Staphylococcus aureus ATCC 25923. MIC quality control ranges were also developed for N. gonorrhoeae ATCC 49226 and S. aureus ATCC 29213. The interpretive criteria for penicillin were as follows: susceptibility, greater than or equal to 47 mm (diameter of inhibition zone) (less than or equal to 0.06 micrograms/ml [MIC]); resistance, less than or equal to 26 mm (greater than or equal to 2 micrograms/ml). For tetracycline they were as follows: susceptibility, greater than or equal to 38 mm (less than or equal to 0.25 microgram/ml); resistance, less than or equal to 30 mm (greater than or equal to 2 micrograms/ml). For spectinomycin they were as follows: susceptibility, >/= 18 mm (</= 32 micrograms/ml); resistance, </= 14 mm (>/= 128 micrograms/ml). For ceftriaxone susceptibility, the criterion was >/= 35 mm (</= 0.25 micrograms/ml) with no other category. Criteria of </= 19 mm for plasmid-mediated resistances to penicillin and tetracycline were also confirmed. The false-susceptibility errors were </= 1% with these criteria.

Stability of SM-7338, a new carbapenem in mediums recommended for the susceptibility testing of anaerobic bacteria and gonococci

The stability of SM-7338 was compared to that of imipenem in media used for susceptibility testing anaerobic bacteria and Neisseria gonorrhoeae. SM-7338 was more stable in all media than imipenem. For tests with anaerobic bacteria, the broth-disk elution (in thioglycolate) and other methods recommended by the National Committee for Clinical Laboratory Standards can be accurately used for SM-7338. However, the cysteine content of IsoVitaleX (25.9 g/L) supplement inactivates SM-7338 (20-fold reduction) in gonococcal susceptibility test systems with GC agar base. A cysteine-free supplement would be advised for tests with the carbapenems and clavulanic acid. The SM-7338 disk diffusion test (10 μg) results were not significantly influenced by the inactivating substances in the media.

Susceptibility testing of Neisseria gonorrhoeae to penicillin and spectinomycin in a diagnostic laboratory.

Agar dilution breakpoint susceptibility testing using GC, DST, and proteose agars, was performed on consecutive clinical isolates of non-penicillinase producing Neisseria gonorrhoeae to examine the feasibility of using such a system in a diagnostic laboratory. The incidence and level of resistance to penicillin and spectinomycin was also assessed. On DST medium 93 of 200 (46.5%) of isolates were of intermediate resistance to penicillin (MIC 0.12-0.5 mg/l) and 21 of 200 (10.5%) were resistant to penicillin (MIC greater than or equal to 1.0 mg/l). Ninety two of 200 (46%) of isolates had an MIC to spectinomycin of 32 mg/l on DST agar. Isolates seemed to be more resistant when tested on the two other media. The methods used in this study could be applied in a routine diagnostic laboratory for immediate clinical benefit and long term epidemiological studies. To enable direct comparisons to be made between populations at different centres, however, methods for gonococcal susceptibility testing need to be standardised.

Lipopolysaccharide masking of gonococcal outer-membrane proteins modulates binding of bacterial cathepsin G to gonococci.

Human polymorphonuclear leucocyte (PMN) lysosomal cathepsin G exerts potent bactericidal action against Neisseria gonorrhoeae in vitro, independent of its serine esterase activity. The results presented demonstrate that (1) bactericidal, diisopropylfluorophosphate-treated cathepsin G binds in a specific and saturable manner to the surface of gonococci, (2) loss of carbohydrates in gonococcal LPS due to mutation increases total and specific binding of cathepsin G, and (3) at least three outer-membrane proteins (OMPs) (PIA, PIII, and a 45 kDa OMP) interact with cathepsin G. Taken together, the results suggest that gonococcal susceptibility to the lethal action of cathepsin G, and perhaps susceptibility of gonococci to oxygen-independent killing by PMNs, is controlled by LPS-masking of cathepsin-G-binding OMPs.

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.

Relationship of the interval between infections and the similarity of gonococcal strains in recurrent gonorrhoea.

Paired gonococcal isolates from 38 patients with recurrent episodes of gonorrhoea at varying intervals were examined for similarity by means of gonococcal auxotyping and susceptibility to antibiotics. A different gonococcal strain was the cause of the second infection in 53% of the patients. Longer intervals between infections were significantly associated with greater numbers of dissimilar strains as a cause of the second infection. The same strain was usually found in infections occurring within 60 days of each other whereas different strains were more likely to cause infections occurring more than 60 days apart. The isolates causing the second infection were significantly more susceptible to penicillin.

Surface Components Affecting Interactions between Neisseria gonorrhoeae and Eucaryotic Cells

Interactions of Neisseria gonorrhoeae with nonleukocytic eucaryotic cells including tissue culture cells (either primary or continuous lines), human sperm, and buccal mucosal cells appear to be influenced primarily by the presence or absence of pili on the bacteria. In this context, piliation enhances attachment to or association of microorganisms with the eucaryotic cells. Pili, on the other hand, appear to reduce interaction of N. gonorrhoeae with mouse peritoneal macrophages. Other groups have demonstrated that pili reduce phagocytosis of gonococci by neutrophils, but in out studies this affect is secondary to that dependent on "leukocyte-association" factor. The presence of such a factor is correlated with a particular protein found by polyacrylamide electrophoresis. Adherence among N. gonorrhoeae varies and results in colony forms of different coloration or aggregation characteristics. These different coloration forms correlate with the protein patterns of gonococci as found in polyacrylamide electrophoresis and also with the susceptibility of gonococci to killing by trypsin.

Regression-line Analysis of Trimethoprim-Sulfamethoxazole Activity againstNeisseria gonorrhoeae

A standardized disk diffusion test was developed and used to test the susceptibility of 102 strains of Neisseria gonorrhoeae to combinations of trimethoprim and sulfamethoxazole (TMP/SMX) by relating zone diameters of inhibition to minimal inhibitory concentrations (MIC's). MIC's for TMP/SMX in ratios of 1:20 ranged from 0.08/1.52 to 2.5/47.5 mug/ml and zones of inhibition ranged from 34 to 10 mm. The coefficient of correlation (r) was -0.75. For comparison, a regression line was similarly calculated for ampicillin. MIC's ranged from 0.02 to 0.32 mug/ml and zones of inhibition ranged from 50 to 31 mm; r was -0.71. With establishment of MIC breakpoints to define the categories, susceptible, intermediate, and resistant, the disk duffusion test would be as reliable for estimating susceptibility of gonococci to TMP/SMX as for estimating susceptiblity to ampicillin.

Comparative Study of Gonococcal Susceptibility to Penicillin in the United States, 1955-1969

Journal Article Comparative Study of Gonococcal Susceptibility to Penicillin in the United States, 1955–1969 Get access John E. Martin, Jr., John E. Martin, Jr. From the Venereal Disease Research Laboratory, Venereal Disease Branch, State and Community Services Division, National Communicable Disease Center, Health Services and Mental Health Administration, Public Health Service, U.S. Department of Health, Education, and Welfare, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Arzell Lester, Arzell Lester From the Venereal Disease Research Laboratory, Venereal Disease Branch, State and Community Services Division, National Communicable Disease Center, Health Services and Mental Health Administration, Public Health Service, U.S. Department of Health, Education, and Welfare, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar Eleanor V. Price, Eleanor V. Price From the Venereal Disease Research Laboratory, Venereal Disease Branch, State and Community Services Division, National Communicable Disease Center, Health Services and Mental Health Administration, Public Health Service, U.S. Department of Health, Education, and Welfare, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar John D. Schmale John D. Schmale From the Venereal Disease Research Laboratory, Venereal Disease Branch, State and Community Services Division, National Communicable Disease Center, Health Services and Mental Health Administration, Public Health Service, U.S. Department of Health, Education, and Welfare, Atlanta, Georgia Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 122, Issue 5, November 1970, Pages 459–461, https://doi.org/10.1093/infdis/122.5.459 Published: 01 November 1970 Article history Received: 04 May 1970 Revision received: 01 July 1970 Published: 01 November 1970