The Evolution of Bacterial Resistance

What types of antibiotic resistance have been identified?

MRSA - Methicillin-Resistant Staphylococcus Aureus

  • These bacteria have become resistant to methicillin, nafcillin, oxacillin, cloxacillin, dicloxacillin, imipenem, and cephalosporins, which are the usual antibiotics used to treat Staphylococcus aureus infections. As a result, more toxic and expensive antibiotics (eg. vancomycin) must be used instead

VRE - Vancomycin-Resistant Enterococcus

  • Strains that have developed resistance to many commonly used antibiotics, but more specifically vancomycin, which is usually the last line of defence against these infections.
  • Enterococci are common bacteria that occur naturally in our bowels, but may become harmful if the body is already weakened from illness (eg. prevalent in hospitals)

PR - Penicillin Resistance

  • Bacteria resistant to the effect of penicillin
  • Historically, Streptococcus pneumoniae was uniformly susceptible to penicillin (bacteria responsible for meningitis, pneumonia, otitis media, sinusitis, and bacteremia in adults and children)
  • This constitutes a serious problem among the elderly, infants, and those with chronic underlying medical conditions or immune systems that are already compromised

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Bacteria in Action | Bacterial vs. Viral Infections | Good and Not-So-Good Bacteria
The Evolution of Bacterial Resistance | Bacterial Infection Dictionary