Antimicrobial Use Guidelines (AMUG) version 21 - UW Health

BLOODSTREAMIssue: Extended-spectrum antibiotics were used when more targeted antibiotics could be used, especially after cultureresults were known. For susceptible staphylococci and streptococci, there was an over-reliance on cefepime. Forsuspected gram-negative organisms, quinolones and cefepime were frequently used, even when Pseudomonasaeruginosa was not suspected or documented.Suggestions:Vancomycin should be used for known or suspected MRSA/MRSE, which are especially common in the ICU and inpatients with extended hospital stays, and then reassessed at 72 hours. With the increased prevalence of CA-MRSA,vancomycin should generally be used until susceptibilities are known. Some patients in the critical care unit withknown Staph aureus may receive daptomycin for up to 48 hours until the vancomycin MIC of the Staph is known.For suspected gram-negative infections in patients with stable renal function, consider more frequent initial use of anaminoglycoside, especially tobramycin, for 48 hours of empiric therapy, and possibly longer. The pharmacist will assistwith pharmacokinetic dosing.For community-based infections not requiring intensive care, and in patients not recently hospitalized (and thus at risk forPseudomonas), ceftriaxone should provide sufficient gram-negative coverage (and reasonable gram-positive coverage).Empiric therapy in the ICU should target Pseudomonas aeruginosa, initially with more than one anti-pseudomonal drug,but then usually narrowing therapy after 72 hours.Issue: For confirmed infections, the antimicrobial choices matched the sensitivity of the microorganisms. 85% of gramnegativebacteremias were treated with a single antimicrobial agent. The lowest MIC is not necessarily the “bestantibiotic” as there are different pharmacokinetic parameters guiding treatment.Suggestion: Continue to match micro-organisms causing infections with appropriate antimicrobial results at 48-72 hours.For selected gram-negative infections involving Pseudomonas, Enterobacter, Serratia and Citrobacter spp., a beta-lactamand aminoglycoside combination regimen may be appropriate. Discussion with Infectious Diseases should be considered.Guidelines for use of combination antimicrobial therapy are forthcoming.URINARY TRACT INFECTIONS (UTIs)Issue: Susceptible streptococci, staphylococci and anaerobes are rarely causes of UTIs. Pseudomonas aeruginosa UTIsin the absence of bacteremia usually do not require two antibiotics for extended treatment.Suggestion: Target pathogens that cause UTIs. When Pseudomonas aeruginosa is isolated, under most circumstances,narrow empiric antibiotic therapy to a single agent, unless the infection is systemic.Issue: Quinolones should not be relied upon for the treatment of enterococcal infections, and moxifloxacin has only 40%urinary excretion and is not indicated for the treatment of UTI.Suggestion: Treat enterococcal infections with penicillin or ampicillin derivatives. Piperacillin/tazobactam has coveragefor enterococci, but should only be used for mixed infections. If a quinolone is indicated for gram-negative infections of theurine, use ciprofloxacin NOT moxifloxacin.Issue: Over-reliance on the use of quinolones to treat nosocomial UTISuggestion: Ceftriaxone has reasonable activity against most gram-negative hospital urinary pathogens, and should beused when Pseudomonas aeruginosa is not isolated, and especially outside the intensive care units.Colonization of the indwelling catheters should not usually be treated. See updated guidelines by the Infectious DiseaseSociety of America. Clinical Infectious Diseases 2010;50:625-663