Gonorrhoea is becoming less sensitive to yet another antibiotic, say researchers in Hawaii

Case reports from Hawaii suggest that strains of the sexually transmitted infection gonorrhoea are emerging which are resistant to the antibiotic selected to replace the previous first-line treatment.

Strains of gonorrhoea which are resistant to penicillin, tetracycline and, most recently ciprofloxacin are already circulating widely in Pacific Rim countries and the USA.

The high prevalence of ciprofloxacin resistant gonnorhoea led to the drug being abandoned as first-choice treatment for the infection in the late 1990s and its replacement with cefixime. As many as 10% of cases of gonnorhoea in the UK are now resistant to ciprofloxacin, and it was recently suggested that the UK should join the USA and no longer use the drug as first-line therapy for the STI, and replace it with cefixime.

Even this strategy may be overtaken by events. Three case reports from early 2001 published in the on-line edition of the 15th September edition of Clinical Infectious Diseases suggest that strains of gonnorhoea are already being transmitted which have reduced susceptibility to cefixime

Case A concerned a 35 year old white man who lived in Hawaii, who presented with a three-day history of symptoms of urethral gonorrhoea. He was treated with a 400mg dose of cefixime. Cultured urethral swabs indicated that the man was infected with a strain of gonorrhoea that was resistant to penicillin, tetracycline, ciprofloxacin and had reduced susceptibility to cefixime. The man returned, complaining of persistent symptoms and was treated with a 2mg intramuscular injection of spectinomycin and a seven day course of 100mg of doxycycline twice daily. A second culture of urethral discharge grew gonorrhoea with the same resistance characteristics as the first swab. Three weeks after the second course of treatment was completed, a test-of-cure showed no growth. The man reported two female sex partners, both of whom had visited Hawaii from Japan.

One of his partners could not be traced, however. Patient B reported a history of vaginal discharge since having sex with patient A. When cultured, the discharge showed that the woman had been infected with gonorrhoea resistant to penicillin, tetracycline and ciprofloxacin, but fully susceptible to cefixime.

Patient C was a 30 year-old Micronesian man living in Hawaii, who attended for treatment after experiencing symptoms suggestive of gonorrhoea for four days. Initial therapy consisted of a single 400mg dose of cefixime with a single 1g dose of azithromycin. When the man’s urethral discharge was cultured it grew gonorrhoea resistant to penicillin, tetracycline, ciprofloxacin and with reduced susceptibility to cefixime. However, a test-of-cure performed three months later was negative for gonorrhoea and the man was symptom-free. The man reported a single female sex partner from the Marshall Islands, however she could not be traced.

The four isolates taken from the three patients were strain-typed and found to be identical.

The investigators comment, “these first US reports of multidrug-resistant ..gonorrhoea with decreased susceptibility to cefixime are of concern because the spread of such strains threatens to further limit treatment options for gonorrhoea.”

Ciprofloxacin-resistant gonorrhoea is highly prevalent in China, Japan and the Philippines, and has spread to Hawaii, where prevalence almost doubled to 20% between 2000 and 2001. Ciprofloxacin-resistant gonorrhoea accounted for under 1% of all cases of the infection in California in 1999, but 5% of all cases of the infection by June 2001.

Several cases of gonorrhoea with reduced susceptibility to cefixime have been identified in Japan since 1999.

The investigators recommend that clinicians treating gonorrhoea should routinely ask their patients about their travel history so appropriate antibiotic treatment can be offered. When cultures identify that a patient has been infected with a strain of gonorrhoea resistant to cefixime contact tracing is essential in order to prevent the ongoing transmission of highly drug-resistant gonorrhoea.

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