Detection of multidrug-resistant gonorrhoea in the Gauteng province

Abstract

Two cefpodoxime-resistant Neisseria gonorrhoeae isolates were identifed with high minimum inhibitory concentrations (MIC) for oral cephalosporins. The ceftriaxone MICs for both isolates were still in the susceptible range, although raised at 0.064 mg/l. Both isolates were cultured from urethral specimens that were collected from male patients who had presented to their general practitioners with urethral discharge. Patient 1 was treated empirically with azithromycin. Patient 2, who reported having had sex with other men, was given intravenous ceftriaxone as he had recently failed two courses of oral cefxime. Both isolates were also highly resistant to ciprofoxacin, resistant to penicillin (ß-lactamase negative) and resistant to tetracycline (and thus doxycycline), and exhibited decreased susceptibility to both azithromycin and gentamicin. On molecular testing, both isolates were found to have mosaic penA genes, which encode for penicillin-binding protein 2. Mosaic penA gene formation is the most common genetic mechanism that is associated with decreased susceptibility to oral cephalosporins. The isolates were typed using the highly discriminatory N. gonorrhoeae multiantigen sequence typing scheme and were found to have identical sequence types. This indicates that it is likely that there has been transmission of a single strain within Gauteng. It is probable that the two cases may be part of the same sexual network.