Drug resistant organisms continue to increase in prevalence and antimicrobial resistance is one of the most significant infectious disease problems. Numerous resources related to Antimicrobial Resistance laboratory testing and the treatment of resistant infections are available online.
Any suspected case of vancomycin intermediate Staphylococcus aureus (VISA), or vancomycin resistant Staphylococcus aureus (VRSA) should be sent to WPHL before reporting to the physician. Testing is also available for drug resistant Streptococcus pneumoniae (DRSP) and Carbipenimase-resistant Enterobacteriaceae (CRE) and Pseudomonas aeruginosa (CRPA). WPHL is no longer performing confirmatory testing for extended spectrum beta lactamase (ESBL).
Type of Test
Reference cultures of isolates will be accepted for identification using biochemical identification systems and MALDI-TOF sequencing.
Growth should be apparent before submission to the laboratory. A pure culture is required.
CRE species for collection and characterization: It is recommended that isolate collection be targeted to Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, and Enterobacter spp. that are resistant to imipenem, doripenem, or ertapenem by standard susceptibility testing methods (i.e., mimimum inhibitory concentrations of > 4 ug/mL for doripenem, imipenem or meropenem or > 2 ug/mL for ertapenem.
CRPA collection and characterization: It is recommended that isolate collection include all Pseudomonas aeruginosa isolates that are resistant to imipenem, meropenem, or doripenem by standard susceptibility testing methods (i.e., mimimum inhibitory concentrations of > 8 ug/mL. Note: Mucoid isolates are excluded and will not be tested.
Ship in a manner to ensure survival of isolate. Ship according to regulations for infectious substances. Complete and enclose WPHL test request form.
DAYS TEST PERFORMED
Daily, Monday – Friday.
Upon completion of identification.
REPORTING & INTERPRETATION
The minimum inhibitory concentration will be reported for each drug tested. Interpretation will include “Resistant”, “Susceptible” or “Intermediate”.
An organism identified as VISA or VRSA will be forwarded to Centers of Disease Control (CDC) in Atlanta. Additionally, organisms that are not readily identifiable may be forwarded to CDC for further identification.