Venessa Maseko

Phenotypic and genetic characterization of the first two cases of extended-spectrum-cephalosporin-resistant Neisseria gonorrhoeae infection in South Africa and association with cefixime treatment failure

OBJECTIVES To describe the phenotypic and genetic characteristics of the first two cases of extended-spectrum cephalosporin (ESC)-resistant Neisseria gonorrhoeae in South Africa, one of which was associated with verified cefixime treatment failure. PATIENTS AND METHODS Two ESC-resistant N. gonorrhoeae isolates were cultured from the urethral discharge of two men who have sex with men (MSM). One man reported a persistent urethral discharge that had failed to respond to previous therapy with oral cefixime. Agar dilution MICs were determined for eight antibiotics. β-Lactam-associated resistance mutations were identified through PCR-based amplification and sequencing for several key genes: penA, mtrR and its promoter, porB1b (penB), ponA and pilQ. For molecular epidemiological characterization, full-length porB gene sequencing, N. gonorrhoeae multiantigen sequence typing (NG-MAST) and multilocus sequence typing (MLST) were performed. RESULTS Both isolates were resistant to cefixime, ciprofloxacin, penicillin and tetracycline and intermediate/resistant to azithromycin, but susceptible to ceftriaxone, gentamicin and spectinomycin. Both isolates had the type XXXIV penA mosaic allele in addition to previously described resistance mutations in the mtrR promoter (A deletion), porB1b (penB) (G101K and A102N) and ponA1 (L421P). Both isolates had an identical NG-MAST sequence type (ST4822) and MLST sequence type (ST1901). CONCLUSIONS Both isolates were resistant to cefixime and possessed a number of identical mutations in key genes contributing to ESC resistance in N. gonorrhoeae. The two isolates contained the type XXXIV penA mosaic allele and belonged to a successful international MSM-linked multidrug-resistant gonococcal clone (MLST ST1901) associated with several cefixime treatment failures in Europe and North America.

Etiology and antimicrobial susceptibility of pathogens responsible for urethral discharge among men in Harare, Zimbabwe.

Background Periodic etiological surveillance of sexually transmitted infection (STI) syndromes is required to validate treatment algorithms used to control STIs. However, such surveys have not been performed in Zimbabwe over the past decade. Methods A cross-sectional study design was used to determine the prevalence of the key STI etiological agents causing male urethral discharge (MUD). Urethral swab specimens were collected for molecular analysis and Neisseria gonorrhoeae isolation from consenting men 18 years and older who presented with MUD to the 12 clinics in Harare, Zimbabwe, between November 2010 and May 2011. A validated in-house multiplex polymerase chain reaction assay was used to detect the presence of N. gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium. Gonococci were cultured on selective media, and antimicrobial susceptibilities were determined locally for ciprofloxacin, kanamycin, ceftriaxone, and cefixime using Etest strips, and minimum inhibitory concentrations were reported using defined breakpoints. Results Among 130 participants, N. gonorrhoeae was the most frequent pathogen detected (106; 82.8%), followed by C. trachomatis (15; 11.7%), M. genitalium (6; 4.7%), and T. vaginalis (2; 1.6%). Four (6.1%) of the 66 gonococci isolated were resistant to fluoroquinolones, whereas all viable isolates were susceptible to kanamycin, cefixime, and ceftriaxone. Conclusions Gonorrhea is the most important cause of MUD in men in Harare, and our study highlights the emergence of fluoroquinolone-resistant N. gonorrhoeae. Further STI surveys are required in other regions of Zimbabwe to obtain a nationally representative picture of gonococcal burden and antimicrobial resistance among MUD patients.

Converging epidemics of sexually transmitted infections and bacterial vaginosis in southern African female adolescents at risk of HIV

Adolescents in Africa are at high risk for HIV infection, other sexually transmitted infections (STIs) and bacterial vaginosis (BV). Since behavior and burden of STIs/BV may influence HIV risk, behavioral risk factors and prevalence of STIs/BV were compared in HIV-seronegative adolescent females (n = 298; 16–22 years) from two South African communities (Soweto and Cape Town). STIs (Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium, herpes simplex virus (HSV)-1, HSV-2, Treponema pallidum, and Haemophilus ducreyi) were detected by multiplex polymerase chain reaction, human papillomavirus (HPV) by Roche Linear Array, and BV by Nugent scoring. Rates of BV (Nugent ≥7; 46.6%) and HPV (66.8%) were high in both communities. Prevalence of C. trachomatis and N. gonorrhoeae were >2-fold higher in Cape Town than Soweto (Chlamydia: 42% [62/149] versus 18% [26/148], p < 0.0001; gonorrhoea 11% [17/149] versus 5% [7/148], p = 0.05). Only 24% of adolescents with vaginal discharge-causing STIs or BV were symptomatic. In South African adolescents, clinical symptoms compatible with vaginal discharge syndrome had a sensitivity of 23% and specificity of 85% for the diagnosis of discharge-causing STI or BV. In a region with high HIV prevalence and incidence, >70% of young women with treatable conditions that could enhance HIV risk would have been missed because they lacked symptoms associated with syndromic management.

Trends in Neisseria gonorrhoeae Antimicrobial Resistance over a Ten-Year Surveillance Period, Johannesburg, South Africa, 2008–2017

Background: In South Africa, sexually transmitted infections (STIs) are managed through a syndromic approach at primary healthcare centres (PHCs). Neisseria gonorrhoeae is the predominant cause of male urethritis syndrome. We describe antimicrobial resistance patterns and trends in Neisseria gonorrhoeae during a ten-year surveillance period at a large PHC in Johannesburg. Methods: Neisseria gonorrhoeae was cultured from genital discharge swab specimens obtained from consenting adult patients presenting at the Alexandra Health Centre in Johannesburg between 2008 and 2017. Isolates were tested for antimicrobial susceptibility by Etest™ (cefixime, ceftriaxone, ciprofloxacin) or agar dilution (penicillin, tetracycline, azithromycin). Results: During the period of surveillance, high-level resistance prevalence increased from 30% to 51% for penicillin (p-value for trend < 0.001), 75% to 83% for tetracycline (p-value for trend = 0.008), and 25% to 69% for ciprofloxacin (p-value for trend < 0.001). Analysis did not reveal high-level resistance to spectinomycin or a minimum inhibitory concentration (MIC) creep for extended-spectrum cephalosporins, and the prevalence of intermediate-resistance to azithromycin was less than 5%. Conclusions: High prevalence resistance to penicillin, tetracycline, and ciprofloxacin in N. gonorrhoeae obviates their use in future national treatment algorithms for genital discharge. It is essential to continue monitoring for emerging resistance to currently recommended antimicrobial therapy in this rapidly evolving pathogen.

Endocervical and vaginal microbiota in South African adolescents with asymptomatic Chlamydia trachomatis infection

Adolescent girls and young women represent a key risk group for sexually transmitted infections (STIs). The vaginal microbiota is thought to play an important role in susceptibility to STIs such as Chlamydia trachomatis. We compared the microbiota of the lateral vaginal wall and endocervix, and assessed associations with C. trachomatis infection in South African adolescents. The endocervical and vaginal lateral wall microbiota were characterized by amplifying and sequencing the V4 region of the 16S rRNA gene and C. trachomatis diagnosed using molecular methods. Of the 72 girls included, 30 had asymptomatic C. trachomatis infections. Three major vaginal community types were identified; one Lactobacillus crispatus, one L. iners and one diverse, Gardnerella vaginalis dominant. The microbiota of the endocervix was significantly different from that of the lateral wall in terms of diversity. There were many differentially abundant taxa between the endocervix and lateral vaginal wall, including Achromobacter spanius and Enterococcus faecium. Women with C. trachomatis had higher relative abundance of G. vaginalis and other anaerobes. In this African adolescent cohort, significant differences between the lateral vaginal wall and endocervical microbiota diversity and composition were evident, although neither were strongly associated with C. trachomatis infection.

P3.186 Neisseria gonorrhoeae antimicrobial resistance surveillance in johannesburg, south africa

Introduction Gonorrhoea is the predominant cause of symptomatic male urethritis in South Africa. Neisseria gonorrhoeae has displayed an alarming propensity to acquire resistance to all sequential first-line antimicrobial agents used over the years. The National Institute for Communicable Diseases has co-ordinated STI microbiological surveillance since 2005 in order to validate existing national syndromic management guidelines. We describe Neisseria gonorrhoeae antimicrobial resistance patterns and trends from Johannesburg surveillance, spanning a period of eight years from 2008 to 2015. Methods Neisseria gonorrhoeae was cultured from swab specimens of genital discharge (endocervical and endourethral) from consenting adult patients presenting to a community-based primary healthcare facility in Johannesburg. The minimum inhibitory concentrations (MICs) of antimcrobials were determined using Etest (cefixime, ceftriaxone, ciprofloxacin) or agar dilution (azithromycin, penicillin, tetracycline). Clinical Laboratory Standards Institute (CLSI) criteria, where applicable, were used for interpretation of results. Descriptive statistics and likelihood-ratio tests in STATA 14 were used for data analysis. Results A total of 2,112 Neisseria gonorrhoeae isolates were tested for susceptibility to the extended-spectrum cephalosporins (ESCs) and ciprofloxacin. A proportion of these were tested for susceptibility to penicillin, tetracycline and azithromycin. Between 2011 and 2015, the prevalence of high-level resistance increased from 31% to 57% for penicillin (p=0.009) and 73% to 91% for tetracycline (p=0.009). Between 2008 and 2015, the prevalence of high-level ciprofloxacin resistance rose exponentially from 24% to 67% (p<0.001). Decreased susceptibility (DS) to cefixime was not observed; however one isolate from 2013 exhibited DS to ceftriaxone. Trend analysis revealed MIC creep for cefixime. Elevated azithromycin MICs of >0.5 µg/ml were identified only in 2015 (5/125; 4%). Conclusion Neisseria gonorrhoeae resistance trends for Johannesburg reveal that high-prevalence resistance to penicillin, tetracycline and ciprofloxacin obviates their use for STI syndromic management. The prevalence of resistance to ESCs is <1% and to azithromycin <5%, validating their continued use in dual therapy. However, it is essential that ESC and azithromycin susceptibility trends are monitored to detect emerging resistance timeously.

Is the new variant of Chlamydia trachomatis present in South Africa

An investigation was conducted to determine the prevalence of the new variant of Chlamydia trachomatis (nvCT) in South Africa (SA). Four hundred and fifty-nine C. trachomatis-positive clinical specimens, tested by in-house multiplex polymerase chain reaction (PCR), were screened for the presence of the 377 bp deletion in the ORF1 of the cryptic plasmid, documented in nvCT, by means of nested PCR. All specimens generated a 630 bp amplicon in the nested PCR, indicative of wild-type CT, and no nvCT strains were identifed. Even though there was no evidence of the presence of nvCT in South Africa, continuous screening for emerging mutant strains is of epidemiological importance.