Since the accesibility of antibiotic treatment, venereal disease, which was associated for centuries with infirmity, disgrace and exile, has lost its horror impact. The treatment, formerly with penicillin but today because of growing resistance using third generation cephalosporins, is considered easy, safe and affordable. Early recognition until now has normally meant early elimination. Drugs of choice include ceftriaxone and cefixime, however single doses of quinolones and macrolides often promises success.
New foms of resistance all the time
Of course (and why should it be any different to other bacterial pathogens treated with antibiotics?) there is no easy solution. Because it isn’t a matter of the bacterium just being resistant to β-lactam antibiotics – Neisseria gonorrhoeae has also defied tetracyclines and flouroquinolones. And finally it appeared to also be resistant to broad-spectrum cephalosporins such as cefixime, for which reason it has in Japan for years no longer been recommended. The agent of first choice there since then has been ceftriaxone and spectinomycin. Even the latter does not guarantee success, and already in January 2009, during a routine throat swab of an asymptomatic prostitute in Kyoto, resistant bacteria were discovered.
The character and the genetic mutations for this new bacterial strain – made significant for its high resistance – with the name HO41 was established by a Japanese-Swedish research team working closely under Magnus Unemo. A molecular typing revealed that the new ceftriaxone-resistant strain of H041 is closely related to the already known cefixime-resistant strain and is highly likely to have emerged from that same one. A very high minimum inhibitory concentration was apparent. The so-called penA gene was able to be identified as the carrier of the new resistance.
N. gonorhoeae – super germ of the future?
With the new resistance, the only remaining option of empirical first-line treatment of gonorrhea is disappearing, say the researchers. They fear that the disease may in the near future become untreatable. The prevention of the disease will therefore gain importance – and in a global sense, as the spread of resistant gonococci into the whole world would follow, coming not for the first time out of this region.
However, prevention and control measures already appear difficult because, since the Infection Protection Act of 2001, cases of the disease do not have to be reported, so that the number of sufferers is obscure.
Only syphilis and HIV are obliged to be reported. A sentinel surveillance system is supposed to have ensured since 2002 that an epidemiological overview of other diseases such as Chlamydia and Gonnorrhoe be maintained. According to the Robert Koch Institute nearly 250 institutions are participating. Thereafter there have been 25 to 40 persons diagnosed annually per 100,000 population. Also, there are no current and no comprehensive studies on resistance. A further complication is that of weak or non-existent discomfort manifestations, primarily in women, which accounts for the spread of the infection, since about half of them have no symptoms at all. Only in two to five percent of men is an asymptomatic progress of the illness to be seen.
An optimal strategy of survival
Hank Seifert from the Northwestern University in Chicago and his colleagues are on the trail of the enormous adaptability of Neisseria gonorrhoeae. They have found out that human DNA fragments have been integrated into the genome of the bacteria. Gene transfer is obviously a process that gives this bacterium, in contrast to other bacteria, including other Neisseria, a survival advantage. Gene transfer between bacteria is known, but the discovery of an exchange between host and bacterium is new and ensures optimal adaptation for the bacterium. New, ever more resistant strains could arise in such a manner.
When the resistant Neisseria strain which developed in Japan might make it to Europe is however currently unclear. Increasingly in demand for quite some time already have been targeted therapies adapted from the antibiogram. The use of antibiotics such as ciprofloxacin, ofloxacin, levofloxacin, amoxicillin, doxycycline or azithromycin could be a possiblity, it says in one article by Thomas Wichelhaus from the Institute for Medical Microbiology and Hospital Epidemiology at the Hospital of the Johann Wolfgang Goethe University in Frankfurt am Main because it’s very doubtful that new treatment options are actually available if they become required.