Clinical and economic evaluation of BBL CHROMagar Salmonella (CHROMSal) versus subculture after selenite broth enrichment to CHROMSal and Hektoen enteric agars to detect enteric Salmonella in a large regional microbiology laboratory.
Stool culture for enteric pathogens is one of the most labor-intensive clinical microbiology procedures. Direct plating of stool to BBL CHROMagar Salmonella (CHROMSal) (BD Diagnostics, Sparks, MD) versus subculture after selenite broth enrichment (Sel) to CHROMSal (Sel-CHROMSal) and Hektoen enteric agar (Sel-Hek) (PML Microbiologicals, Eugene, OR) to detect Salmonella were compared. The number of colony picks and biochemical/serotyping tests per plate was recorded. A cost comparison was done. Fifty-one of 2999 (1.7%) stools yielded Salmonella sp., and 80% of isolates grew on CHROMSal by 24 h. CHROMSal demonstrated much less false-positive growth compared to Sel-Hek (P < 0.0001), which reduced biochemical and serotyping tests by 85% and 20%, respectively. Sel-CHROMSal and CHROMSal versus Sel-Hek improved enteric Salmonella detection when compared to a true positive "gold standard" (i.e., recovery by any culture method) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% and 94.12%, 100% and 99.97%, 100% and 97.96%, and 100% and 99.90%, respectively. CHROMSal use would result in substantial cost and labor savings.
Church
Deirdre L
DL
Calgary Laboratory Services (CLS), Calgary, Alberta, Canada. deirdre.church@cls.ab.ca
Emshey
Diana
D
Lloyd
Tracie
T
Pitout
Johann
J
D000362:Agar; D015373:Bacterial Typing Techniques / Q000191:economics / Q000379:methods; D001431:Bacteriological Techniques / Q000191:economics / Q000379:methods; D002863:Chromogenic Compounds / Q000378:metabolism*; D003470:Culture Media; D005243:Feces / Q000382:microbiology*; D006801:Humans; D011237:Predictive Value of Tests; D012475:Salmonella / Q000145:classification* / Q000302:isolation & purification*; D012480:Salmonella Infections / Q000382:microbiology; D012680:Sensitivity and Specificity; D018038:Sodium Selenite / Q000378:metabolism
D002863:Chromogenic Compounds; D003470:Culture Media; D000362:Agar; D018038:Sodium Selenite