ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00457.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Polymerase chain reaction (PCR) was used after a short pre‐enrichment culture to detectSalmonellasubspecies in chicken fillets. A direct PCR assay performed with chicken meat inoculated withSalmonella Typhimuriumproduced no PCR products. Six different DNA extraction protocols were tested to recover efficientlySalmonellaDNA after a short incubation period. Three of them gave results that were reliable, rapid and sensitive. Successful protocols used Proteinase K and/or a centrifugation step to concentrate the samples. For reliable detection ofSalmonellasubspecies, a few thousand bacterial cells per ml must be present. To obtain this number of bacterial cells with an inoculation of about one cell in 25 g of ionized food products, it was necessary to incubate samples for at least 10 h before PCR. A larger inoculum of approximately 10 cells in 25 g of ionized food products, required 8 h in culture broth to give positive results by PCR‐based as

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00458.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Extracts of black and green tea inhibitedin‐vitrogrowth of six clinical isolates ofHelicobacter pyloriin an agar diffusion assay. Tea extracts killedH. pylori(106cfu ml‐1) within 5 h. Heat treatment of extracts did not affect the inhibitory or bactericidal activ

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00459.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A PCR assay has been developed for the detection ofCampylobacter jejuniandCamp. coliin water samples. The sample is filtered through a membrane which is subjected to sonication to release the impacted cells. After removal of the filter from the cell suspension and a freeze/thaw cell lysis step, a semi‐nested PCR is carried out on the filtrate using the primers CF02, CF03 and CF04 (Camp. jejuni flaandflaBgene sequences). Incorporation of a sonication stage allows removal of the filter membrane since they have been shown to inhibit the PCR. In experiments with spiked water samples (20 ml) a theoretical sensitivity of 10–20 Campylobacter cells ml‐1was achieved. Using a sample volume of 100 ml this sensitivity can be increased to approximately 2 Campylobacter cells

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00460.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Vero cytotoxin (VT)‐producingEscherichia coliO157 (0157 VTEC) were isolated from a raw beefburger obtained from a retail source linked to a small community outbreak of 0157 VTEC infection in Wales. Strains from the meat and from seven of eight patients belonged to phage type 49 and were indistinguishable by their VT‐type, plasmid content and hybridization with DNA of a VT‐encoding phage from an 0157 VTEC strain. This first report of the isolation of 0157 VTEC from a beef product in Britain supports the view that there is a bovine reservoir for this org

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00461.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The 18S rRNA gene sequence of the ascomycete yeastLodderomyces elongisporuswas determined by PCR‐direct sequencing. The phylogenetic inter‐relationship ofLodderomyces elongisporusand other ascomycete yeast species was examined by comparative sequence analysis.Lodderomyces elongisporuswas found to be most closely related toCandida parapsilosis, C. tropicalisandC. albicans, exhibiting sequence similarity values of greater than 97.5%. The relationship betweenL. elongisporusandCandida parapsilosisin particular is discussed with regard to the possibility thatL. elongisporusis the teleomorph (sexual form) ofC. parapsilo

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00462.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Sub‐lethal injury ofEscherichia colihas been detected following centrifugation atg‐forces between 5 and 30 kg. The extent of injury was measured either as a reduction in colony forming ability when plated onto NaCl‐containing plates (2% w/v), or as a reduction in transformation efficiency associated with plasmid pBR322 encoding ampicillin resistance. In both cases, the extent of sub‐lethal injury was found to increase with increasing centrifugal force and probably reflects structural damage to the cell e

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00463.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A rapid and direct fluorogenic assay was used to detectEscherichia coliin urine. Most clinical isolates ofE. coliproduce β‐glucuronidase, whereas almost all other enterobacteria lack the enzyme. Spectrofluorimetric assay of β‐glucuronidase, without previous induction, was performed on growing and starved uropathogenicE. coliin artificial urine. The presence of 103cfu ml‐1ofE. coliin urine was detected by β‐glucuronidase activity in less than 1 h. These results indicate that β‐glucuronidase is a rapid, specific and sensitive indicator of the presence ofE. coliin urine, and provide additional information on the biological state of the infecting bacteri

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00464.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

In the microbiological examination of water, indicator organisms are sought by membrane filtration of 100‐ml sub‐samples of water. The same sample cannot be examined twice but the use of split samples, where two 100‐ml sub‐samples from the same batch are processed, has been explored. Binomial theory was used to determine the 95% confidence intervals for the results obtained. Two sets of 50 results were assessed by the method and the resulting control charts are illu

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00465.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A chromogenic test withl‐prolinep‐nitroanilide as a substrate was developed to detect proline iminopeptidase activity fromEikenella corrodens.Optimal assay conditions for enzyme detection were 50°C and pH 7.5–8.0. Forty paper point samples from adult periodontitis patients were screened forEik. corrodensand proline iminopeptidase activity, to determine whether this enzyme is a marker for the pathogen. Twenty samples were positive forEik. corrodens, and the levels of enzyme activity and populations ofEik. corrodenswere found to correlate (P

ISSN:0266-8254    

DOI:10.1111/j.1472-765X.1994.tb00466.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY