Quantitation of Staphylococcus aureus in seawater using CHROMagar SA.
A microbiological algorithm has been developed to analyze beach water samples for the determination of viable colony forming units (CFU) of Staphylococcus aureus (S. aureus). Membrane filtration enumeration of S. aureus from recreational beach waters using the chromogenic media CHROMagar SA alone yields a positive predictive value (PPV) of 70%. Presumptive CHROMagar SA colonies were confirmed as S. aureus by 24-hour tube coagulase test. Combined, these two tests yield a PPV of 100%. This algorithm enables accurate quantitation of S. aureus in seawater in 72 hours and could support risk-prediction processes for recreational waters. A more rapid protocol, utilizing a 4-hour tube coagulase confirmatory test, enables a 48-hour turnaround time with a modest false negative rate of less than 10%.
Tice
Alan D
AD
Department of Medicine, John A. Burns School of Medicine, University of Hawai'i at Manoa, Honolulu, HI, USA. alantice@idlinks.com
Pombo
David
D
Hui
Jennifer
J
Kurano
Michelle
M
Bankowski
Matthew J
MJ
Seifried
Steven E
SE
D000362:Agar; D015373:Bacterial Typing Techniques / Q000379:methods*; D015169:Colony Count, Microbial; D006801:Humans; D012623:Seawater / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D014871:Water Microbiology
D000362:Agar