BC Bio Empiric Therapy Antibiogram 2011

Here is the 2011 version of the BC Bio antibiogram. Our antibiogram has been designed primarily to be used by clinicians treating patients before the susceptibility data has been received.

Common organisms are grouped according to the diseases they most frequently cause with that purpose in mind, rather than alphabetically or by Gram stain results. Antibiotics are listed orals first, and grouped by antibiotic classes. The susceptibility rates reflect the spectrum of patients served by BC Bio, namely outpatients and patients living in various residential facilities. Strains of MRSA, Enterococcus, and Pseudomonas from patients with recent and/or prolonged hospitalizations are more likely to be multiply-resistant; otherwise the expected susceptibility patterns for most common organisms are not greatly affected by hospital exposure. Patients with recent and/or prolonged antibiotic exposures are also at increased risk of harbouring resistant bacteria.

What is notable in the 2011 antibiogram?

The long trend of increasing prevalence of methicillin resistance amongst Staphylococcus aureus appears to have halted, while an increasing proportion of MRSA strains appear to be “community-associated” strains which are more susceptible to second-line antibiotics. The committee overseeing susceptibility testing guidelines, Clinical and Laboratory Standards Institute (CLSI), changed its criteria for cefazolin susceptibility twice in 2010 with the result that certain cefazolin susceptibilities no longer reflect clinical response to standard dosing. The CLSI has also determined that susceptibility testing of cephalexin does not reliably predict clinical response of certain coliform infections. Therefore, BC Bio has suspended reporting cefazolin and cephalexin susceptibilities for coliform bacteria in order not to mislead prescribing physicians. Amongst coliforms, susceptibility rates to ciprofloxacin and third generation cephalosporins [which had dropped significantly over the past decade] appear to have stabilized.

What is coming in 2011?

We have seen only the first cases of NDM-1 and other carbapenemases, but more are expected in the coming years. We will soon be reporting ertapenem susceptibilities on coliforms as many of the hospital physicians are now prescribing this agent on a once-daily basis for outpatients.

Click here to download a pdf of the 2011 Antibiogram