TY - JOUR
T1 - Phenotypic and genotypic characterization of Pseudomonas fluorescens isolated from bulk tank milk
AU - Wang, L.
AU - Jayarao, B. M.
N1 - Funding Information:
The authors thank the Minnesota-South Dakota Dairy Foods Research Center (Brookings, SD) for funding the project. The authors acknowledge the support of D. R. Henning, Alfred Chair, for use of laboratory facilities.
PY - 2001/6
Y1 - 2001/6
N2 - Pseudomonas fluorescens isolates (n = 55) isolated from farm bulk tank milk (n = 55) from dairy herds in eastern South Dakota and western Minnesota were examined for phenotypic (biotype, proteolytic, and lipolytic profiles) and genotypic (plasmid profiles and 16S-23S PCR ribotypes) characteristics. The observed phenotypic and genotypic characteristics were used to conduct phylogenetic analysis. Pseudomonas fluorescens belonged to 28 API 20 NE biotypes and 14 proteolytic and lipolytic profiles. It was observed that 80, 91, and 58% of the isolates were proteolytic at 7, 22, and 32°C, respectively. Only 7, 44, and 7% of the isolates were lipolytic at the same three temperatures. Pseudomonas fluorescens was more likely to produce proteinases at 7 and 22°C and lipases at 22°C. Only 9 of 55 isolates of P. fluorescens harbored plasmids. This small percentage of plasmid-bearing isolates provided insufficient data for inferences related to the distribution of plasmid-bearing clonal types. Based on 16S-23S PCR ribotyping, P. fluorescens belonged to 14 subtypes. The 16S-23S PCR ribotyping technique allowed differentiation between strains; however, it did not concur with the biotypes and proteolytic and lipolytic profiles. Use of biotypes in conjunction with proteolytic and lipolytic profiles might have practical value for conducting trace-back studies related to P. fluorescens. Based on phylogenetic analysis, it was inferred that for the given geographical area and time period, P. fluorescens isolated from farm bulk tank milk consists of a large heterogeneous group of organisms.
AB - Pseudomonas fluorescens isolates (n = 55) isolated from farm bulk tank milk (n = 55) from dairy herds in eastern South Dakota and western Minnesota were examined for phenotypic (biotype, proteolytic, and lipolytic profiles) and genotypic (plasmid profiles and 16S-23S PCR ribotypes) characteristics. The observed phenotypic and genotypic characteristics were used to conduct phylogenetic analysis. Pseudomonas fluorescens belonged to 28 API 20 NE biotypes and 14 proteolytic and lipolytic profiles. It was observed that 80, 91, and 58% of the isolates were proteolytic at 7, 22, and 32°C, respectively. Only 7, 44, and 7% of the isolates were lipolytic at the same three temperatures. Pseudomonas fluorescens was more likely to produce proteinases at 7 and 22°C and lipases at 22°C. Only 9 of 55 isolates of P. fluorescens harbored plasmids. This small percentage of plasmid-bearing isolates provided insufficient data for inferences related to the distribution of plasmid-bearing clonal types. Based on 16S-23S PCR ribotyping, P. fluorescens belonged to 14 subtypes. The 16S-23S PCR ribotyping technique allowed differentiation between strains; however, it did not concur with the biotypes and proteolytic and lipolytic profiles. Use of biotypes in conjunction with proteolytic and lipolytic profiles might have practical value for conducting trace-back studies related to P. fluorescens. Based on phylogenetic analysis, it was inferred that for the given geographical area and time period, P. fluorescens isolated from farm bulk tank milk consists of a large heterogeneous group of organisms.
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U2 - 10.3168/jds.S0022-0302(01)70174-9
DO - 10.3168/jds.S0022-0302(01)70174-9
M3 - Article
C2 - 11417701
AN - SCOPUS:0035380610
SN - 0022-0302
VL - 84
SP - 1421
EP - 1429
JO - Journal of dairy science
JF - Journal of dairy science
IS - 6
ER -