Typing of Neisseria gonorrhoeae Reveals Rapid Reinfection in Rural South Africa

Abstract

A recent study afforded us the opportunity to collect pre-and post-treatment isolates of Neisseria gonorrhoeae from women who supposedly failed to eradicate the organism when tested 8 to 10 days following treatment with a single, directly observed 250-mg dose of ciprofloxacin. In an attempt to differentiate true treatment failure from reinfection, we determined the ciprofloxacin MICs and performed auxotyping, serotyping, and opa typing of the pre-and post-treatment isolates. Paired isolates of N. gonorrhoeae were obtained from seven different women, despite susceptibility of the initial isolates to ciprofloxacin. Six of seven patients were infected with gonococcal isolates that differed significantly from their primary isolate. These most probably represent reinfection with a different strain, which could originate from the same partner infected with multiple strains or reinfected with a new strain or from a different partner. The susceptibility to ciprofloxacin of all isolates makes the possibility of multiple strains in the patient unlikely. The diversity of the isolates within the pairs therefore suggests rapid reinfection within the partnerships.Infections with Neisseria gonorrhoeae are of concern to health care providers because they carry an increased risk of morbidity and mortality among women (3) as well as neonates (6). In addition, as with the other causes of sexually transmitted infections (STIs), they represent an elevated risk for infection with human immunodeficiency virus (HIV) (2, 5). Epidemiological surveillance including accurate strain identification is pivotal to the understanding of the transmission dynamics of this organism, which in turn influences public health interventions.In a recent study, we evaluated the efficacy of the drugs employed in the syndromic management of nonulcerative STIs among women (8). Twenty percent of women treated with ciprofloxacin for culture-proven infection with N. gonorrhoeae remained culture positive when tested between 8 and 10 days later. We attributed the subsequent infection to either lack of compliance with antibiotic therapy, failure of the ingested antibiotics to eradicate the infecting organism, or reinfection.In our setting, ciprofloxacin is the drug of choice for the treatment of cervicitis due to N. gonorrhoeae and is administered as a directly observed single dose. Lack of compliance therefore cannot explain the subsequent infection. Although the MICs of ciprofloxacin for N. gonorrhoeae have started to increase in this area (7), clinical failures have not as yet been seen. Attempts at partner notification and treatment have been largely ineffectual (16). We suspect that reinfection is common, but this has not been proven.In an attempt to differentiate true treatment failure from reinfection, we determined the phenotype by using auxotyping, serotyping, and antibiograms of pre-and post-treatment isolates and examined the genetic relatedness by means of opa typing. Our hypothesis was that the isolates within each pair would be susceptible to ciproflo...

Molecular Epidemiology of Neisseria gonorrhoeae in Amsterdam, The Netherlands, Shows Distinct Heterosexual and Homosexual Networks

“…When we considered the intervals between visits, we found the turnover time of infection to be no higher than the median of 113 days. A much higher rate of reinfection with different strains was seen in South Africa although in a smaller study population: six out of seven female patients had isolates with a different opa RFLP pattern 8 to 10 days after their initial consultation (13).…”

Review and International Recommendation of Methods for Typing Neisseria gonorrhoeae Isolates and Their Implications for Improved Knowledge of Gonococcal Epidemiology, Treatment, and Biology

“…However, Opa typing has the same disadvantages as RFLP methods, including labor-intensiveness, subjectiveness, and a need for pronounced standardization for interlaboratory comparisons. Opa typing has been used to define gonococcal populations within a geographic area, for the identification of clusters of strains (8,9,19,20,26,49,65,71,74,93,96,104,118,121,127,174,182,186,189), for tracing strain transmission between sexual contacts (9,19,74,186), for resolving suspicions of reinfection (102), for substantiation of treatment failure (77,102), and for detection of mixed infection (102). Opa typing has been used to increase the discriminatory power of other typing methods, including full-or extended-length porB sequencing or NG-MAST in specific situations, especially those involving extreme microepidemiological analysis (19,65,96,104,174,186) (Table 1).…”

Management of vaginal discharge syndrome: how effective is our strategy?

“…The results of a recent study [12], in conjunction with a previous report [13], imply that about 20% of female STD clinic attendees become rapidly reinfected (within 7 days), after successful drug treatment for Neisseria gonorrhoeae infection.…”