Interpretation of a Culture and Sensitivity Report

1 DISCLAIMER:Video will be taken at this clinicand potentially used inProject ECHO promotional materials. By attending this clinic, youconsent to have your photo taken and allow Project ECHO to use this photo and/or video. If you don t wantyour photo taken, please let us know. Thank you!ECHO Nevada emphasizes patient privacy and asks participants to not share ANY Protected Health Information during ECHO of a Culture and Sensitivity ReportJESSICA THOMPSON, PHARMD, BCPS (AQ- ID)..GoalsBriefly review the Interpretation of Culture and Sensitivity C/S reportTracheal aspirate: Pseudomonas aeruginosaAntibioticMICI nterpretationAztreonam8 SCeftriaxone> 32 RCeftazidime4 SCiprofloxacin 1 SGentamicin2 SMeropenem 1 SPiperacillin/tazobactam a C/S ReportWHAT IT TELLS YOUI dentifies bacteria/fungus present(most of the time) Sensitivity results based on lab data Human vs lab WHAT IT DOES NOTTELL YOU Does not identify infection vs colonization vs contamination Don t treat colonization or contaminationDoes not tell you which antibiotic to Susceptibility testing is an in vitro phenomenon and does not necessarily reflect or predict in vivo efficacy.

2 Susceptibility testing is subject to great variability depending on pathogen tested, media used, conditions of incubation, and method of accessing bacterial growth BURKE A C/S reportTracheal aspirate: Pseudomonas aeruginosaAntibioticMICI nterpretationAztreonam8 SCeftriaxone> 32 RCeftazidime4 SCiprofloxacin 1 SGentamicin2 SMeropenem 1 SPiperacillin/tazobactam Minimum concentration of an antibiotic needed to inhibit visible growth of a single isolate of an organism Important for definitive treatment of an individual patientBreakpoint Discriminatory concentrations used in the Interpretation of results of susceptibility testing to define isolates as susceptible, intermediate, or resistant (determinedby various organizations - FDA, CLSI, EUCAST)..Which antibiotic should you use?Tracheal aspirate: Pseudomonas aeruginosaAntibioticMICI nterpretationAztreonam8 SCeftriaxone> 32 RCeftazidime4 SCiprofloxacin 1 SGentamicin2 SMeropenem 1 SPiperacillin/tazobactam #1 ALWAYS START WITH A BETA-LACTAM IF POSSIBLE, ESPECIALLY IN SEVERE INFECTIONS They have the best data supporting their use and are in general excellent drugs Exception: atypical #2DO NOT COMPARE MICS BETWEEN DRUGS Each antibiotic has different pharmacokinetics Different serum concentrations Different tissue concentrations Each antibiotic has different goal pharmacodynamic parameters Time vs concentration vs AUC/MIC dependent.

3 Rule #3IF YOU CAN USE THE DRUG (NOTE EXCEPTIONS BELOW) Exceptions Drug doesn t get to the site of action Drug doesn t achieve its goal pharmacodynamics parameters Drug doesn t have inducible resistance Patient-specific factors Drug #4 MICROBIOLOGY ALWAYS HAS MORE INFORMATION THAN WHAT IS REPORTEDThey may have results before they are reported in the computerAntibiotics may be suppressedThey can perform additional question #1 Blood Culture :Enterococcus faecalisAntibioticMICI nterpretationAmpicillin<=2 SDaptomycin1 SPenicillin2 SVancomycin2 SWhich antibiotic should you use?..Assessment question #1 Blood Culture :Enterococcus faecalisAntibioticMICI nterpretationAmpicillin<= 2 SDaptomycin1 SPenicillin2 SVancomycin2 SRule #1: Always start with a beta-lactam if possibleRule #2: Do not compare MICs between drugsRule #3: If <= you can use the drug with some exceptionsRule #4: Micro always has more information.

4 Assessment question #1 Rule #1: Always start with a beta-lactam if possible The drug of choice for ampicillin-sensitive enterococcus is AmpicillinRule #2: Do not compare MICs between drugs Daptomycin is not better than ampicillin because the MIC is lower Amicillin is still the drug of choice if sensitiveRule #3: If <= you can use the drug with some exceptions True; cost effectiveness: ampicillin > vancomycin > daptomycin Rule #4: Microbiology always has more information that what is reported Microbiology also tests linezolid, which is the only oral option for treatment of this bacteremia (ampicillin is still preferred)Answer: AMPICILLIN 2 gm IV question #2 Which antibiotic should you use?..Assessment question #2 You need more information Cystitis or pyelonephritis? If cystitis, is it a male or female? If female, how old?Let s assume this is CYSTITIS in a YOUNG ADULT FEMALE with no co-morbid conditions Do you want IV or PO?

5 Assessment question #2 Rule #1: Always start with a beta-lactam if possible Cefotetanand meropenemare the only sensitive beta-lactamsRule #2: Do not compare MICs between drugsRule #3: If <= you can use the drug with some exceptions Exceptions Cefotetanshould not be used for ESBL-producing organisms and is IV Meropenemis appropriate but is IV Ciprofloxacin is resistant so levofloxacin should not be used Tigecyclinehas poor urine penetration and is IV NitrofurantoinRule #4: Microbiology always has more information that what is reported Fosfomycincan also be tested but is question #2 Answer: Macrobid 100 mg PO BID x 5 is always more to the evaluation that just an S Use a beta-lactam if at all possibleNever use the smallest number just because it is the smallest numberKnow the exceptionsAsk for help if