MDRO pathogens that are frequently been implicated in severe healthcare-associated infections (HAIs) and have important infection control implications are the following:

  • Gram-positive: methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE);
  • Gram-negative: Pseudomonas aeruginosa, Acinetobacter baumanni and Enterobacteriaceae that are resistant to at least one agent in three or more antimicrobial categories (see table) and organisms such as Stenotrophomonas maltophilia and Burkholderia cepacia, that are intrinsically resistant to the broadest-spectrum antimicrobial agents.

Table: Antimicrobial categories used to define MDR gram-negative bacteria.

Enterobacteriaceae

Pseudomonas aeruginosa

Acinetobacter spp

Aminoglycosides

Aminoglycosides

Aminoglycosides

Cephalosporins

Antipseudomonal cephalosporins (ceftazidime, cefepime)

Antipseudomonal carbapenems (Imipenem, Meropenem, Doripenem)

Carbapenems (Ertapenem, Imipenem, Meropenem, Doripenem)

Antipseudomonal carbapenems (Imipenem, Meropenem, Doripenem)

Antipseudomonal fluoroquinolones (ciprofloxacin, levofloxacin)

Antipseudomonal penicillins + beta-lactamase inhibitors

Antipseudomonal fluoroquinolones (ciprofloxacin, levofloxacin)

Antipseudomonal penicillins + beta-lactamase inhibitors

Fluoroquinolones

Antipseudomonal penicillins + beta-lactamase inhibitors (piperacillin/tazobactam, ticarcillin-clavulanic acid)

Extended spectrum cephalosporins (cefotaxime, ceftriaxone, ceftazidime, cefepime)

Folate pathway inhibitors

Monobactams

Folate pathway inhibitors

Glycylcyclines

Phosphonic acids

Penicillins + beta-lactamase inhibitors (ampicillin/sulbactam)

Monobactams

Polymyxins

Polymyxins

Penicillins

 

Tetracyclines

Phenicols

 

 

Phosphonic acids

 

 

Polymyxins

 

 

Tetracyclines

 

 

 

References.

  • Magiorakos AP, Srinivasan A, Carey RB, Carmeli Y, Falagas ME, Giske CG, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: An international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect. 2012; 18:268-81.