First Case of Neisseria Gonorrhoeae Mosaic PenA60 Allele Identified in United States

December 14, 2020
Killian Meara

The U.S. sentinel surveillance program is a project which monitors for antibiotic-resistant gonorrhea.

The Southern Nevada Public Health Laboratory of the Southern Nevada Health District (SNHD) has recently identified a male urethral gonococcal isolate which has demonstrated a reduced susceptibility to cefixime and ceftriaxone. However, the bacteria was shown to be susceptible to azithromycin. Cefixime, ceftriaxone and azithromycin are antibiotics that are used to treat various types of bacterial infections.

The CDC performed molecular testing on the emerging mosaic penA60 allele that was first identified in Japan in 2016. The bacteria, which has a reduced susceptibility to cephalosporins, has also shown to increase the risk for treatment failure.

The penA60 allele has been identified in a multitude of other countries, including Canada, Australia, Denmark, China, France and the United Kingdom. The case identified in Nevada is the first known case of a Neisseria gonorrhoeae isolate harboring the mosaic penA60 allele reported in the United States.

The gonococcal isolate was collected from an HIV-negative, heterosexual male with penile discharge and dysuria. The patient was treated with the currently recommended regimen of ceftriaxone (250 mg) given intramuscularly, along with azithromycin (1 g) administered orally. The SNHD performed Nucleic acid amplification tests (NAATs) and collected cultures from the patient, which were negative for N. gonorrhoeae. The CDC later confirmed the isolate from urethral samples.

The SNHD gathered 5,500 gonococcal isolates from the southern Nevada area to attempt to identify other cases of N. gonorrhoeae with the penA60 allele, but all were negative. An advisory was sent to State and local jurisdictions in early 2020, but the investigation was stopped due to the fact no other cases had been identified.

Since this first case of the N. gonorrhoeae with the penA60 allele in the United States, no further spread has been documented. This case shines light on the value and importance of the surveillance programs, which can be an effective tool in identifying emerging antimicrobial-resistant pathogens which can impact public health.