EVALUATION OF FUNG DOUBLE TUBE TEST FOR CLOSTRIDIUM PERFRINGENS AND EASYPHAGE TEST FOR F-SPECIFIC RNA COLIPHAGES AS RAPID SCREENING TESTS FOR FECAL CONTAMINATION IN RECREATIONAL WATERS OF HAWAII

ABSTRACT

The previously reported Fung double tube (FDT) for Clostridium perfringens and the newly developed EasyPhage test for F-specific RNA coliphages were evaluated as screening tests for fecal contamination of fresh and marine recreational waters in Hawaii. These two tests were used to analyze water samples from marine swimming beaches, streams, nonswimming coastal waters and raw sewage. The major advantages of the FDT test include formation of anaerobic conditions without the need of anaerobic chamber systems and enumeration of colonies of C. perfringens in the tubes within 6 h. The results showed that 5 mL of water sample and 20 mL of 2× Shahidi Ferguson Perfringens medium were the best combination for the enumeration of C. perfringens in 5–6 h at 42C. This is a candidate, rapid beach monitoring method which can be used to close the beach on the same day the water samples were collected. The major advantages of the EasyPhage method include the rapid formation of gel without the use of heat, and addition of streptomycin and ampicillin to control interfering bacterial contamination. These two test methods allow most water laboratories to monitor environmental waters for C. perfringens and F-specific RNA coliphages as indicators of fecal contamination.

PRACTICAL APPLICATIONS

Monitoring fecal contamination in water around the world is of great importance in public health. This paper presents rapid and efficient methods to monitor Clostridium perfringens and F-specific RNA coliphages in waters in Hawaii, USA. The 6-hour Fung-Double Tube (FDT) system for enumeration of C. perfringens in water by use of SFP agar and incubation at 42C was perfected. The EasyPhage method by Scientific Methods, LLC (Grander, IN) for enumeration of FRNA coliphages in water using an ingenious nonthermal gelling system incubated for 12–16 h at 35C was tested. A Fung/Fujioka Scale (I = uncontaminated, acceptable, II = nonpoint contamination, III = sewage contamination, and VI = elevated sewage contamination, unacceptable) was developed to group the contamination level of recreational water for Hawaii. Forty-six water samples were evaluated by both methods with excellent information concerning C. perfringens and FRNA phage in water in Hawaii.