How CORE-ABR grades it
Intrinsic resistance applied: ampicillin, amoxicillin-clavulanate, ampicillin-sulbactam, first-generation cephalosporins (cefazolin) and cephamycins (cefoxitin). Because AmpC can be induced or derepressed during therapy, third-generation cephalosporins are treated with caution for serious infection.
What the report shows for Citrobacter freundii
- Detected or not detected, with Ct, limit of detection and cycles above LOD — see PCR reporting.
- A short pathogen summary, including colonizer likelihood where it applies.
- A graded column on the antibiogram, and therapy options by scenario on the P.A.C.T. report.
- When not detected, it is still listed among targets tested.
Resistance genes CORE-ABR applies
When detected, each of these genes is applied to Citrobacter freundii only for the agents its mechanism defeats.
Class C beta-lactamase (AmpC)AmpC cephalosporinase production5 organisms on panelClass A beta-lactamase (CTX-M)Extended-spectrum beta-lactamase (ESBL) production6 organisms on panelClass A beta-lactamase (KPC / SHV)Carbapenemase (KPC) or ESBL (SHV variants) production5 organisms on panelqnrA / qnrBPlasmid-mediated quinolone resistance7 organisms on paneldfrA1 / dfrA5Trimethoprim resistance6 organisms on panelsul1 / sul2Sulfonamide resistance6 organisms on panel
Tagged
Decision support only. The treating clinician decides. Molecular genotype does not replace phenotypic susceptibility testing, culture, or public-health reporting. Absence of a detected resistance gene does not establish susceptibility. Organism targets vary by panel; CORE-ABR is configured to the assay each laboratory runs.