Thesis (PhD Med.(Microbiology))--University of Limpopo, 2010. / Studies were performed on local isolates of Neisseria gonorrhoeae to assess their aetiological role in
different clinical populations, to determine the evolution of antimicrobial resistance and
characterisation of quinolone resistance.
In the study performed on women presenting for termination of pregnancy (TOP) the prevalence of
common sexually transmitted pathogens (Neisseria gonorrhoeae, Chlamydia trachomatis and
Trichomonas vaginalis) was much higher than reported from other studies in TOP populations. The
commonest organism isolated was C. trachomatis. There were no significant differences in infection
rates in women with or without signs and symptoms of vaginal discharge. Therefore all women
presenting for TOP need to be screened and treated for sexually transmitted pathogens.
In the study to determine the co-infection rates in men presenting with urethritis (discharge and/or
burning on micturition (BOM)), the overall infection rate was 65% with co-infections (more than one
pathogen detected) in 8%. N. gonorrhoeae was found in 45%, C. trachomatis in 15% and T. vaginalis
in 6% of the men. T. vaginalis was found in higher percentages in men with BOM only, in the
absence of visible discharge. There may be a need to add an anti-trichomonicidal agent in men
presenting with BOM only.
When comparing sexual partners and the pathogens isolated, significantly fewer pathogens were
detected in males that had their wives as sole contact when comparing them to men who had sex
with casual contacts, reflecting high sexual risk behaviour.
M DE JONGH Page xi
PhD Med Microbiology
N. gonorrhoeae isolates were obtained from men presenting to a general practitioner in Pretoria
with urethral discharge. The antimicrobial susceptibility profile was determined to currently used,
previously used and potential antimicrobial agents by the disk diffusion, Etest and agar dilution
methods.
High-level ciprofloxacin resistance emerged in the Pretoria region at 7%. No isolate showed a MIC
value of intermediate resistance, suggesting importation of resistant strains, rather than a step-wise
incremental increase. Penicillin-resistant gonococcal isolates are entrenched in the community;
overall there was 32% resistance (MIC≥2μg/mℓ), with 16% due to penicillinase-producing (PPNG)
isolates. Tetracycline-resistant isolates has increased dramatically at 54% and with 36% showing
high-level (plasmid-mediated) resistance. All isolates remained susceptible to ceftriaxone, cefoxitin
and cefpodoxime.
Local gonococcal isolates were sequenced using Neisseria gonorrhoeae Multi-Antigen Sequence
Typing (NG-MAST). In this study a total of 18 isolates resolved into 13 different sequence types
(STs). A cluster of four isolates of known sequence type, ST217, was found. Two other known
sequence types (ST189 & ST523) have previously been seen in Durban. The ten quinolone-resistant
isolates resolved into six STs, five of which were new STs and one cluster of four isolates of a known
sequence type. This demonstrates the heterogeneity of ciprofloxacin-resistant strains suggesting
introduction of strains from multiple sources rather than clonal spread of a single strain.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/277 |
| Date | January 2010 |
| Creators | De Jongh, Mari |
| Publisher | University of Limpopo (Medunsa Campus) |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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