Monday, December 28, 2015

Gonorrhea: The Path Of Increased Resistance

Credit CDC PHIL - photomicrograph Neisseria gonorrhoeae.


Despite 75 years of effective antibiotic treatments, gonorrhea remains the second most common STD in the United States. In 2009 the CDC recorded 301,174 cases of gonorrhea, and by 2014 that number had jumped to over 350,000.

It is estimated that more than half of all cases go unreported. 

The introduction of penicillin in the 1940s represented the first truly effective treatment, and for the next 30 years, penicillin and tetracycline both proved powerful weapons against this disease.

But by the 1970s penicillin/tetracycline resistant forms of Neisseria gonorrhoeae began to appear in the United States, and by the 1980s had become common.  In response, the CDC began recommending cephalosporins as the first-line treatment for gonorrhea.

In 1993, the CDC also recommended the use of fluoroquinolones (i.e., ciprofloxacin, ofloxacin, or levofloxacin) to treat gonorrhea, as they were relatively cheap, effective, and allowed for a 1 dose treatment.

But in less than a decade, fluoroquinolone-resistant N. gonorrhoeae (QRNG) emerged out of Asia and began showing up in Hawaii and then California (see MMWR Increases in Fluoroquinolone-Resistant Neisseria gonorrhoeae --- Hawaii and California, 2001).

In 2007, the CDC announced Fluoroquinolones No Longer Recommended for Treatment of Gonococcal Infections, leaving just one class of antibiotics - the cephalosporins - still recommended and available for the treatment of gonorrhea.

Today, a combination therapy of a cephalosporin (cefixime or ceftriaxone), along with a macrolide antibiotic (preferably azithromycin) are the only recommended treatments that remain for Gonorrhea.

Given the history of its gaining increased resistance over the decades, it is of little surprise that we are beginning to see early evidence of failure with this last line of defense, with an outbreak of `super gonorrhea' in Leeds, England earlier this year (cite BBC report). 

A bleak prospect envisioned more than four years ago in a  2011 MMWR report called Cephalosporin Susceptibility Among Neisseria gonorrhoeae Isolates --- United States, 2000—2010, which contained the following editorial comment:

The epidemiologic pattern of cephalosporin susceptibility in the West and among MSM during 2009--2010 is similar to that previously observed during the emergence of fluoroquinolone-resistant N. gonorrhoeae in the United States (2--3,7). Although the history of fluoroquinolone-resistant N. gonorrhoeae might not predict the patterns of decreasing cephalosporin susceptibility, the observed trends are concerning.

The bottom line, again from the editorial comment is:

In light of the diminished resources available to STD control programs and the past inability to prevent emergence of resistance, the eventual emergence of cephalosporin resistance appears likely.

All of this is making headlines once again this weekend, as Dame Sally Davies - England's Chief Public Health Officer - has issued a warning that:

Gonorrhoea 'could become untreatable'

Gonorrhoea could become an untreatable disease, England's chief medical officer has warned. 

Dame Sally Davies has written to all GPs and pharmacies to ensure they are prescribing the correct drugs after the rise of "super-gonorrhoea" in Leeds.

Her warning comes after concerns were raised that some patients were not getting both of the antibiotics needed to clear the infection. 

Sexual health doctors said gonorrhoea was "rapidly" developing resistance.
(Continue . . . )

None of this comes as any surprise to public health officials, as this issue has been on their radar for years.   Some earlier reports include:

Referral: McKenna On Almost-Untreatable Gonorrhea

WHO: Urgent Action Needed On Resistant Gonorrhea

CDC Grand Rounds: Multidrug-Resistant Gonorrhea

Resistant gonorrhea is just one prong of our growing antibiotic resistance problem, something which author, blogger, and journalist Maryn Mckenna has been writing and talking about for more than a decade. 

If you haven't already seen it, I highly recommend you view:

Maryn McKenna’s TED Talk - What do we do when antibiotics don’t work any more?


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