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antibiotic resistance


  • whenever antibiotics are used, this puts biological pressure on bacteria that promotes the development of resistance
  • we are rapidly heading into the “post-antibiotic era” - when our antibiotics are near useless against our major infections and the organisms continue to evolve with ever higher degrees of antibiotic resistance
  • despite billions of dollars research, science has not been able to produce new types of antibiotics over the last few decades to meet this threat
  • in this scenario we can expect not only will our complication rates and mortality rates increase from infectious illnesses, but complex surgical patients, those with immunosuppression such as HIV / AIDS patients, cancer patients on chemotherapy, dialysis patients, transplant patients, and patients with autoimmune diseases such as severe rheumatoid arthritis on immunosuppressants will also have much higher morbidity and mortality
  • much of this is due to indiscriminate antibiotic usage, particularly in our food chain.
  • whilst most antibiotic resistant organisms are picked up during a hospital admission, increasingly, these are community acquired, particularly, MRSA, tuberculosis (TB), pneumococcus, and gonorrhoea.

current threats

urgent threats

    • this bacteria spreads rapidly because it is naturally resistant to many drugs used to treat other infections
    • fluoroquinolone resistant strain emerged in 2000
    • deaths related to C. difficile increased 400% between 2000 and 2007, mainly in those older than 65 yrs
  • Carbapenem-resistant Enterobacteriaceae (CRE) (PDR-Enterobacteriaceae identified in 2009)
    • includes E.coli and Klebsiella sp
    • some Enterobacteriaceae are resistant to nearly all antibiotics, including carbapenems, which are often considered the antibiotics of last resort
    • a major issue in Asia, but rapidly spreading globally
    • in 2019, it was shown that seagulls in Australia have high rates of antibiotic resistant E.coli as detected by their fecal droppings and presumably could spread this to migrating birds and other animals
  • Drug-resistant Neisseria gonorrhoeae (ceftriaxone resistance identified in 2009)
    • currently < 1% in US are resistant to ceftriaxone or azithromycin but up to 30% have antibiotic resistance to penicillins, tetracycline &/or fluoroquinolones
    • in 2017, azithromycin non-susceptible N. gonorrhoeae are now common in Australia
    • increasing resistance to ceftriaxone and azithromycin will have an enormous impact

serious threats

  • multidrug-resistant Acinetobacter (identified in 2004/2005)
    • mainly an issue for critically patients
    • most Acinetobacter are now multidrug resistant
  • Drug-resistant Campylobacter
    • in the US, a quarter are now resistant to azithromycin or ciprofloxacin
  • Fluconazole-resistant Candida
    • the fourth most common cause of healthcare-associated bloodstream infections in the US where 7% of Candida systemic infections are now resistant to fluconazole
  • Vancomycin-resistant Enterococcus (VRE) (identified in 1988, gentamicin resistance in 1979)
    • in the US, ~30% of Enterococcus healthcare-associated infections are vancomycin resistant
  • Multidrug-resistant Pseudomonas aeruginosa
    • in the US, 13% of severe healthcare-associated infections caused by Pseudomonas aeruginosa are multidrug resistant
  • Drug-resistant Non-typhoidal Salmonella
  • Drug-resistant Salmonella Typhi
    • in the US, ~2/3rds of cases are resistant to ciprofloxacin
  • Drug-resistant Shigella (tetracycline resistance identified in 1959)
  • Methicillin-resistant Staphylococcus aureus (MRSA) (identified in 1962)
  • Drug-resistant Streptococcus pneumoniae (penicillin resistance identified in 1965)
  • Drug-resistant tuberculosis (TB) (XDR TB identified in 2000)
    • MDR TB shows resistance to at least INH and rifampicin (RMP), the two essential first-line drugs
      • 1% of cases in US are MDR TB
    • XDR TB is defined as MDR TB plus resistance to any fluoroquinolone and to any of the three second-line injectable drugs (i.e., amikacin, kanamycin, capreomycin)

concerning threats

  • Vancomycin-resistant Staphylococcus aureus (VRSA) (identified in 2002, ceftaroline resistance in 2011 only 1 year after ceftaroline was introduced)
    • VRSA is currently rare
  • Erythromycin-resistant Group A Streptococcus (identified in 1968)
  • Clindamycin-resistant Group B Streptococcus

minimising impact of antibiotic resistance

  • prevent infections and the spread of resistant organisms
    • minimise hospital admissions and length of stay
    • vaccinations - eg. pneumococcal vaccine
    • safe sex
    • reduce foodborne infections - improved sanitation, food handling, safe food and water
    • hand washing
    • minimise travel to regions with high antibiotic resistance such as Asia
    • contact tracing
  • tracking resistance
  • improve use of antibiotics
    • remove from food chain
    • improved prescribing indications to reduce unnecessary prescribing
    • ensure appropriate regimes to minimise development of resistant organisms (esp. tuberculosis (TB))
  • develop new diagnostic tests to better target antibiotic usage and find sources of contamination
  • develop new antibiotics
    • unlikely to play a major role

web articles

antibiotic_resistance.txt · Last modified: 2019/07/10 10:44 (external edit)