Volume 22, Number 5—May 2016
Technological Solutions to Address Drug-Resistant Neisseria gonorrhoeae
To the Editor: Since the 1930s, Neisseria gonorrhoeae has become resistant to drugs in every class of antimicrobial therapy used to treat it. We read with interest the article by Martin et al. about trends in Canada on N. gonorrhoeae susceptibility to third-generation cephalosporins, the only class of antimicrobial drugs to which most N. gonorrhoeae strains remain susceptible (1). We find the reported decrease in cefixime- and ceftriaxone-reduced susceptibility during 2010–2014 encouraging, but remain concerned about a threat from drug-resistant and untreatable N. gonorrhoeae infections: a similar downward trend in the United States reversed in 2014 (2). That divergence demonstrates the limited reliability of surveillance data.
Addressing resistance requires new methods for susceptibility determination without culture. Real-time screening for genes associated with antimicrobial drug resistance, such as penA mosaic alleles yielding decreased susceptibility to oral extended-spectrum cephalosporins, may be a valuable method to determine treatment (3). In the same issue of Emerging Infectious Diseases, Deguchi et al. described a case of multidrug-resistant N. gonorrhoeae (4), further highlighting the urgency for the innovative approach of using molecular tests to individualize treatment regimens. An ongoing study supported by the National Institutes of Health (R21AI109005) is evaluating how a laboratory-developed molecular N. gonorrhoeae genotypic susceptibility test for ciprofloxacin enables rapid identification of effective antimicrobial drugs (5).
N. gonorrhoeae may acquire new resistance mechanisms under selection pressures imposed by use of antimicrobial drugs and horizontal gene transfer from other commensal Neisseria species resident in the human oropharynx (3). Inconsistent pharyngeal N. gonorrhoeae screening may lead to missed opportunities for treatment. A National Institutes of Health program (Antibiotic Resistance Leadership Group, award no. UM1AI104681) is ongoing to assist manufacturers in obtaining US Food and Drug Administration approval for molecular assays to detect extragenital gonococcal infections.
For nearly 8 decades, N. gonorrhoeae has been controllable. Continued investment in research and the development of new laboratory technology are critical in supporting an effective response to mitigate the threat of untreatable gonorrhea.
We received funding from National Institute of Allergy and Infectious Diseases R21AI109005. C.C.B. received funding from National Institute on Drug Abuse T32 DA023356 and National Institute on Drug Abuse R01 DA037773-01A1.
- Martin I, Sawatzky P, Liu G, Allen V, Lefebvre B, Hoang L, Decline in decreased cephalosporin susceptibility and increase in azithromycin resistance in Neisseria gonorrhoeae, Canada. Emerg Infect Dis. 2016;22:65–7.
- Kirkcaldy RD, Hook EW III, Soge OO, del Rio C, Kubin G, Zenilman JM, Trends in Neisseria gonorrhoeae susceptibility to cephalosporins in the United States, 2006–2014. JAMA. 2015;314:1869–71 .
- Buono SA, Watson TD, Borenstein LA, Klausner JD, Pandori MW, Godwin HA. Stemming the tide of drug-resistant Neisseria gonorrhoeae: the need for an individualized approach to treatment. J Antimicrob Chemother. 2015;70:374–81.
- Deguchi T, Yasuda M, Hatazaki K, Kameyama K, Horie K, Kato T, New clinical strain of Neisseria gonorrhoeae with decreased susceptibility to ceftriaxone, Japan. Emerg Infect Dis. 2016;22:142–4.
- Hemarajata P, Yang S, Soge OO, Humphries RM, Klausner JD. Performance and verification of a real-time PCR assay targeting gyrA gene for prediction of ciprofloxacin resistance in Neisseria gonorrhoeae. J Clin Microbiol. 2016;54:805–8.