A methods comparison for the isolation and detection of thermophilic Campylobacter in agricultural watersheds.
Campylobacter species contribute to an enormous burden of enteric illnesses around the world. This study compared two different methods for detecting Campylobacter species in surface water samples from agricultural watersheds across Canada. One method was based on membrane filtration (MF) of 500 ml water samples followed by selective microaerophilic enrichment at 42 degrees C in Bolton broth, isolation of Campylobacter on CCDA, and subsequent identification confirmation by a PCR assay. The second method was based on centrifugation (CF) of 1000 ml water samples, followed by selective microaerophilic enrichment at 42 degrees C in Bolton broth, isolation of Campylobacter on Modified Karmali Agar, and subsequent identification confirmation by a different PCR assay. Overall comparison of the CF and MF methods indicated that both methods found Camylobacterjejuni to be the most commonly detected Campylobacter species in 699 water samples from four agricultural watersheds across Canada, and that C. jejuni frequency of occurrence was similar by both methods. However, the CF method detected significantly higher frequencies of Campylobactercoli (17%) and other Campylobacter species (13%) than the MF method (11% and 3%, respectively). It was frequently found that one method would detect Campylobacter in a water sample when the other method would not for a simultaneously collected, duplicate water sample. This study indicates that methods can have significantly different recovery efficiencies for Campylobacter species, and that caution is needed when comparing studies that report on the frequency of occurrence of waterborne Campylobacter at the genus level when different detection methods are used.
Khan
Izhar U H
IU
Aquatic Ecosystem Protection Research Division, Water Science & Technology Directorate, National Water Research Institute (NWRI), Environment Canada, Burlington, Ontario, Canada L7R 4A6.
Gannon
Vic
V
Loughborough
Alyssa
A
Jokinen
Cassandra
C
Kent
Rob
R
Koning
Wendell
W
Lapen
David R
DR
Medeiros
Diane
D
Miller
Jim
J
Neumann
Norman
N
Phillips
Rob
R
Robertson
Will
W
Schreier
Hans
H
Topp
Edward
E
van Bochove
Eric
E
Edge
Thomas A
TA
D015373:Bacterial Typing Techniques / Q000379:methods*; D002167:Campylobacter / Q000235:genetics / Q000302:isolation & purification*; D002498:Centrifugation / Q000379:methods; D003470:Culture Media; D004587:Electrophoresis, Agar Gel; D005374:Filtration / Q000379:methods; D005618:Fresh Water / Q000382:microbiology*; D005798:Genes, Bacterial; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014871:Water Microbiology
D003470:Culture Media; D012336:RNA, Ribosomal, 16S