Primary Care Corner with Geoffrey Modest MD: antibiotic-resistant bacteria of concern

By Dr. Geoffrey Modest

The WHO just published a list of 12 bacterial families that they feel pose the greatest threat to human health (see http://www.who.int/mediacentre/news/releases/2017/bacteria-antibiotics-needed/en/ ). These are considered the “priority pathogens”, which should serve as a focus for research and development of new antibiotics. The most critical group includes multi-drug-resistant bacteria that pose a particular threat in hospitals, nursing homes, and among patients who require devices such as ventilators and blood catheters. These bacteria have become resistant to a large number of antibiotics including carbapenems and third-generation cephalosporins, the best available drugs for treating multidrug resistant bacteria. The 2nd and 3rd tier priorities include increasingly drug-resistant bacteria that can cause more common diseases such as gonorrhea and salmonella. The goal is to spur governments to incentivize basic science and advance research and development, both public and private sector, to invest in new antibiotic discovery. The list does not include tuberculosis, which does have increasing resistance, but is covered by other programs.

Priority 1: critical

  1. Acinetobacter baumanii, carbapenem-resistant
  2. Pseudomonas aeruginosa, carbapenem-resistant
  3. Enterobacteriaceae, carbapenem-resistant, ESBL-producing

Priority 2: high

  1. Enterococcus faecium, vancomycin-resistant
  2. Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant
  3. Helicobacter pylori, clarithromycin-resistant [see http://blogs.bmj.com/bmjebmspotlight/category/gi-h-pylori/​ for multiple blogs on H Pylori resistance and optimal treatment strategies]
  4. Campylobacter spp., fluoroquinolone-resistant
  5. Salmonellae, fluoroquinolone resistant
  6. Neisseria gonorrheae, cephalosporin-resistant, fluoroquinolone-resistant

Priority 3: medium

  1. Streptococcus pneumoniae, penicillin-non-susceptible
  2. Haemophilus influenzae, ampicillin-resistant
  3. Shigella spp., fluoroquinolone-resistant

Commentary:

  • This WHO publication follows others which have warned of scarily increasing bacterial antibiotic-resistance world-wide (e.g., see http://blogs.bmj.com/bmjebmspotlight/2014/07/11/primary-care-corner-with-geoffrey-modest-md-whos-remarkable-scary-report/ )​
  • The focus of this current publication is to spur on research and development of new antibiotics.  BUT, though not mentioned, the elephant in the room is that we need to decrease the future development and spread of antibiotic-resistant bacteria. Some of this is decreasing the unnecessary use of antibiotics for nonbacterial illnesses (see prior blogs, as below, in the file: http://blogs.bmj.com/bmjebmspotlight/category/id-microbial-resistance/). But the largest part of this has to do with industrial use of antibiotics in livestock, where antibiotics are used to increase the weight of animals and prevent infections largely in the setting of huge industrial farms, where there is great opportunity for sharing of pathogens. Although there are different estimates out there on the quantity of antibiotics used, one study by the Union of Concerned Scientists suggested that 24.6 million pounds of antimicrobials are used annually for nontherapeutic purposes in chickens, cattle, and swine vs 3.0 million pounds used for humans (see Landers TF. A review of antibiotic use in food animals: perspective, policy, and potential. Public Health Rep. 2012 Jan-Feb 127(1): 4.).  i.e. 90% goes to animals….
  • An additional issue is that drug companies have been loath to develop new antibiotics. As for-profit organizations, they see much more income from life-long drugs, such as those for lipids, diabetes, etc. (the gift that keeps on giving), vs those prescribed for just a 10-day course. (The apparent exception is for hepatitis c, where the meds are given for several months, these were new meds for a very serious and very common condition, and they were able to jack up the price independent of their actual costs of R&D). And, many of the drug-resistant bugs, at this point, are in areas of the world where there is not lots of money to be made (see http://apps.who.int/iris/bitstream/10665/112642/1/9789241564748_eng.pdf?ua=1​ ) .  From the blog of 7/11/14: “at this point we really need new antibiotics developed. There have been no new class of antibiotics since 1987. Issue is that the $$ is in chronic meds. Even over-charging for antibiotics doesn’t help much if it’s for only a 10 day course. And, will append below a previous blog  which shows that the vast majority of R&D by big pharma is for look-alike drugs and not for important break-throughs (though their arguments supporting the huge costs of drugs hinges on the expense of R&D)”
  • So, bottom line, we do need new antibiotics to deal with the spread of these “superbugs”. But we really do need to intensify internal pressure on clinicians to decrease antibiotic overprescribing and, especially, external pressure on industrial farming to dramatically decrease antibiotic usage.

 

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