Propidium monoazide–quantitative polymerase chain reaction for viable Escherichia coli and Pseudomonas aeruginosa detection from abundant background microflora

2013 ◽  
Vol 441 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Eva Theres Gensberger ◽  
Angela Sessitsch ◽  
Tanja Kostić
2016 ◽  
Vol 19 (3) ◽  
pp. 619-625 ◽  
Author(s):  
C.H. Dai ◽  
L.N. Gan ◽  
W.U. Qin ◽  
C. Zi ◽  
G.Q. Zhu ◽  
...  

AbstractAn efficient and accurate method to testEscherichia coli(E. coli) adhesion to intestinal epithelial cells will contribute to the study of bacterial pathogenesis and the function of genes that encode receptors related to adhesion. This study used the quantitative real-time polymerase chain reaction (qPCR) method. qPCR primers were designed from thePILINgene ofE. coliF18ab, F18ac, and K88ac, and the pig β-ACTINgene. Total deoxyribonucleic acid (DNA) fromE. coliand intestinal epithelial cells (IPEC-J2 cells) were used as templates for qPCR. The 2−ΔΔCtformula was used to calculate the relative number of bacteria in cultures of different areas. We found that the relative numbers of F18ab, F18ac, and K88ac that adhered to IPEC-J2 cells did not differ significantly in 6-, 12-, and 24-well culture plates. This finding indicated that there was no relationship between the relative adhesion number ofE. coliand the area of cells, so the method of qPCR could accurately test the relative number ofE. coli. This study provided a convenient and reliable testing method for experiments involvingE. coliadhesion, and also provided innovative ideas for similar detection methods.


2015 ◽  
Vol 36 (11) ◽  
pp. 1337-1343 ◽  
Author(s):  
Emilie Bédard ◽  
Céline Laferrière ◽  
Dominique Charron ◽  
Cindy Lalancette ◽  
Christian Renaud ◽  
...  

OBJECTIVETo perform a post-outbreak prospective study of the Pseudomonas aeruginosa contamination at the faucets (water, aerator and drain) by culture and quantitative polymerase chain reaction (qPCR) and to assess environmental factors influencing occurrenceSETTINGA 450-bed pediatric university hospital in Montreal, CanadaMETHODSWater, aerator swab, and drain swab samples were collected from faucets and analyzed by culture and qPCR for the post-outbreak investigation. Water microbial and physicochemical parameters were measured, and a detailed characterization of the sink environmental and design parameters was performed.RESULTSThe outbreak genotyping investigation identified drains and aerators as the source of infection. The implementation of corrective measures was effective, but post-outbreak sampling using qPCR revealed 50% positivity for P. aeruginosa remaining in the water compared with 7% by culture. P. aeruginosa was recovered in the water, the aerator, and the drain in 21% of sinks. Drain alignment vs the faucet and water microbial quality were significant factors associated with water positivity, whereas P. aeruginosa load in the water was an average of 2 log higher for faucets with a positive aerator.CONCLUSIONSP. aeruginosa contamination in various components of sink environments was still detected several years after the resolution of an outbreak in a pediatric university hospital. Although contamination is often not detectable in water samples by culture, P. aeruginosa is present and can recover its culturability under favorable conditions. The importance of having clear maintenance protocols for water systems, including the drainage components, is highlighted.Infect. Control Hosp. Epidemiol. 2015;36(11):1283–1291


2014 ◽  
Vol 12 (4) ◽  
pp. 763-771 ◽  
Author(s):  
Jingrang Lu ◽  
Tammie L. Gerke ◽  
Helen Y. Buse ◽  
Nicholas J. Ashbolt

A quantitative polymerase chain reaction assay (115 bp amplicon) specific to Escherichia coli K12 with an ABITM internal control was developed based on sequence data encoding the rfb gene cluster. Assay specificity was evaluated using three E. coli K12 strains (ATCC W3110, MG1655 & DH1), 24 non-K12 E. coli and 23 bacterial genera. The biofilm detection limit was 103 colony-forming units (CFU) E. coli K12 mL−1, but required a modified protocol, which included a bio-blocker Pseudomonas aeruginosa with ethylenediaminetetraacetic acid buffered to pH 5 prior to cell lysis/DNA extraction. The novel protocol yielded the same sensitivity for drinking water biofilms associated with Fe3O4 (magnetite)-coated SiO2 (quartz) grains and biofilm-surface iron corrosion products from a drinking water distribution system. The novel DNA extraction protocol and specific E. coli K12 assay are sensitive and robust enough for detection and quantification within iron drinking water pipe biofilms, and are particularly well suited for studying enteric bacterial interactions within biofilms.


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