Gonorrhoea appears to be growing increasingly resistant to drugs called cephalosporins, the only remaining class of antibiotics available to treat the sexually transmitted disease, according to a new report.
Researchers analysed 10 years' worth of gonorrhoea samples (isolates) from men in 30 US cities. The samples were collected between January 2000 and June 2010 through the US Centers for Disease Control and Prevention's Gonococcal Isolate Surveillance Project.
The analysis revealed an increase in the proportion of samples with elevated minimum inhibitory concentrations (MICs), the lowest concentration of antibiotics needed to halt the growth of gonorrhoea bacteria. These increases in MICs suggest a decline in gonorrhoea's susceptibility to antibiotics, the researchers explained in a CDC news release.
During the study period, the percentage of gonorrhoea samples exhibiting elevated MICs rose from 0.2 to 1.4% of samples for cefixime (an oral cephalosporin) and from 0.1 to 0.3% for ceftriaxone (an injectable cephalosporin).
To date, there are no recorded cases of patients with gonorrhoea that couldn't be treated with these antibiotics in the United States. The study is published in the CDC's Morbidity and Mortality Weekly Report.
Antibiotics for gonorrhoea
The researchers called for increased efforts to develop new treatments and a boost in gonorrhoea surveillance in order to identify emerging patterns of antibiotic resistance in gonorrhoea as they occur.
Over time, gonorrhoea has developed resistance to several antibiotics. The CDC currently recommends dual therapy of cephalosporins with either azithromycin or doxycycline. Treatment options would become substantially limited if gonorrhoea becomes resistant to cephalosporins, the researchers warned.
Left untreated, gonorrhoea can cause infertility in women and increase the risk of infection with HIV, the virus that causes Aids, for men and women.