Plasmid content, auxotype and protein-I serovar of gonococci isolated in the Gambia

Johnson, Alan P.; Abeck, Dietrich; Wall, R.A.; Mabey, David; Taylor‐Robinson, David

doi:10.1017/s0950268800066528

Cited by 11 publications

(7 citation statements)

References 13 publications

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“…However, only a few studies have used the panel of monoclonal antibodies to determine the serotype [20,23,24]. In this study the gonococcal population was heterogeneous, although there were fewer serovars and A/S classes among the PPNG than the non-PPNG.…”

Section: Resultsmentioning

confidence: 99%

“…Dissemination of penicillinase plasmids is dependent on the presence of the conjugative plasmid for transfer between strains of N. gonorrhoeae [16]. The conjugative plasmid is often found in combination with the Asian (6-8 kb) penicillinase plasmid and this could account for the spread of these PPNG worldwide including many countries in Africa [17][18][19][20][21][22]. In contrast PPNG harbouring both the 5 0 kb plasmid and the 38 kb conjugative plasmid have been isolated less frequently and its spread has been more limited.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection

et al. 1993

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SUMMARYOne hundred and ninety-two strains of Neisseria gonorrhoeae isolated from migrant mine-workers were tested for their susceptibility to antibiotics, auxotyped and serotyped. Of the total, 93 (48%) were acquired locally and 64 (33%) from different geographical locations. Plasmid-mediated resistance to penicillin was found in 28 (14-6%) strains and was associated predominantly with the presence of 5 0 kb penicillinase encoding plasmid (18/28, 64 %). Chromosomal resistance to penicillin (MIC ) 1 mg/l) was detected in 14 (73 0%) strains. Resistance to tetracycline was chromosomally and not plasmid-mediated. Antibiotic resistance was encountered most commonly among strains acquired in Natal. The overall gonococcal population was sensitive to ceftriaxone, ciprofloxacin, spectinomycin and azithromycin. Nine auxotype/serovar (A/S) classes were encountered among penicillinase-producing N. gonorrhoeae (PPNG) compared to 24 A/S classes among non-PPNG strains. The most common A/S class was NR/IA-6 which accounted for 38 % of PPNG and 15 % of non-PPNG.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection

et al. 1993

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“…Other possible cellular functions of PI have been suggested, such as translocation into recipient membranes (3,49) and association with PG (Hill, Ph.D. thesis). PI subclass has been associated with such traits as serum resistance (12,29,38,57), resistance to antibiotics (1, 8,33,35,59), auxotype (5,24,47,54,64), and expression of type 1 or type 2 immunoglobulin Al (IgAl) protease (54). The role of PI in pathogenesis remains elusive, but the PI subclass has been associated with certain clinical states such as disseminated gonococcal infection and localized mucosal disease (5,9,50,54,56,64).…”

Section: Functionmentioning

confidence: 99%

Protein I: structure, function, and genetics

Judd

1989

Clin Microbiol Rev

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The study of the major outer membrane (OM) protein, protein I (PI), of Neisseria gonorrhoeae has proven to be as fascinating, and as frustrating, as every other aspect of this remarkable bacterium. However, intensive studies over the last few years have provided significant insight into the structure, function, and genetics of this abundant, surfaceexposed porin protein. There are two forms of PI, which share up to 80% homology. The diversity of the exposed portion of the molecules among strains presents an everchanging immunogenic and antigenic dilemma to the reinfected host. Yet, it is the variability of the PI surface epitopes that has provided a precise method of serotyping N. gonorrhoeae, making it possible to monitor the prevalence and spread of strains within the host population and correlate functional differences between strains with PI structural types.Recent successes in cloning and sequencing of both P1 structural subclasses have already contributed to our understanding of the mechanisms) whereby N. gonorrhoeae generates PI structural diversity. Continued investigation is needed to clarify the relationship between PI type and disseminated disease, resistance to serum killing, auxotypic requirements, interaction with host cells, and resistance to antibiotics. Observations regarding the ability of PI to interact with eucaryotic membranes suggest a role for PI in the pathogenesis of N. gonorrhoeae, whereas immune responsiveness of patients to PI points to the possibility of a PI vaccine. Clearly, at the molecular level, PI represents all the mystery and intrigue that N. gonorrhoeae presents at the organism level. Certainly, much remains to be learned before we have a complete picture of the structure, function, and genetics of PI. STRUCTURE PI (73) is known to exist in two structurally related forms, designated subclass PIA and subclass PIB (61), which have different orientations in the OM (2, 4). A given strain or N. gonorrhoeae expresses a single, invariant PI of one of the other subclass, which accounts for up to 60% of the protein in the OM (36), whether grown aerobically or anaerobically (16). There is significant structural variation within the subclasses, resulting in proteins of different apparent molecular mass (52,72), different isoelectric points (with some as low as 5.5, but most close to 8.0) (3), and unique immunological reactivities (6,45,(61)(62)(63)75). PIAs tend to be smaller than PIBs, ranging in apparent molecular mass from about 34 to 36.5 kilodaltons (kDa), whereas PIBs range from about 36 to 38 kDa (38,52,72,73) (Fig. 1). Regardless of subclass, PIs appear to associate as trimeric porins which form hydrophilic channels through the OM (3,19,51,78). Proteins of both subclasses show immunological variation (6,45,(61)(62)(63)75), which tends to be localized in surface-exposed portions of the molecules (13,40,42,44,46,75 (13,14,23). There is 65 to 80% homology between PIA and amino acid sequences of the two PIBs, confirming similarities previously observed by peptide mapping (2,39,40,6...

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“…The epidemiology of antibiotic resistance in N. gonorrhoeae has been reported in two previous studies in The Gambia (Johnson et al 1987;Ison et a/. 1992).…”

Section: Discussionmentioning

confidence: 68%

Increasing prevalence of penicillinase‐producing Neisseria gonorrhoeae and the emergence of high‐level, plasmid‐mediated tetracycline resistance among gonococcal isolates in The Gambia

Adegbola

Sabally

Corrah

et al. 1997

Tropical Med Int Health

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One hundred and three strains of Neisseria gonorrhoeae isolated from a periurban STD clinic in The Gambia were studied for antimicrobial susceptibility, plasmid profile, and serogroup using standard procedures. Seventy-nine (77%) were penicillinase producers (PPNG) and fully resistant to penicillin (MIC > or = 8 mg/l). One isolate showed chromosomally induced resistance to penicillin (MIC 2 mg/l). None of the isolates was sensitive to tetracycline; 16 (16%) showed intermediate resistance (MICs 1-8 mg/l) and 87 (84%) showed high-level plasmid-mediated resistance (TRNG) (MICs > 10 mg/l). This is the first report of TRNG in The Gambia. Only 6 (6%) strains were fully sensitive to trimethoprim-sulphamethoxazole (MIC < 8 mg/l); 78 (76%) showed intermediate level resistance (MICs 8-16 mg/l) and 19 (18%) were fully resistant (MIC > 32 mg/l). Indications of an increase in MIC to ciprofloxacin and ceftriaxone were found in 6 (6%) and 1 (1%) strains, respectively, although all remained fully sensitive (MICs 0.004-0.03 mg/l and 0.001-0.015 mg/l). All PPNG and TRNG strains carried the 3.2 MDa and 25.2 MDa plasmids, respectively. All isolates carried the 2.6 MDa cryptic plasmid and 9 (3 PPNG and 6 non-PPNG) carried the 24.5 MDa conjugative plasmid. Forty-four (43%) strains were typed group W1, 58 (56%) W11/111 and 1 had cross-reacting antigens. Because PPNG are frequently encountered and high-level TRNG is now prevalent, the newer cephalosporins and quinolones must now be considered as first-line drugs for the treatment of gonorrhoea in The Gambia.

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Plasmid content, auxotype and protein-I serovar of gonococci isolated in the Gambia

Cited by 11 publications

References 13 publications

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection

Antimicrobial susceptibilities and serotyping of Neisseria gonorrhoeae in southern Africa: influence of geographical source of infection

Protein I: structure, function, and genetics

Increasing prevalence of penicillinase‐producing Neisseria gonorrhoeae and the emergence of high‐level, plasmid‐mediated tetracycline resistance among gonococcal isolates in The Gambia

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