Application evaluation of modified TT enrichment broth in separation of intestinal pathogenic Salmonella and Shigella bacteria / 国际检验医学杂志

Objective To analyze the effect evaluation of modified TT enrichment broth in the separation of intestinal pathogenic Salmonella and Shigella bacteria .Methods The routine inoculation of Macconkey agar and SS agar were adopted ,meanwhile two different methods for adding the modified TT enrichment broth(sodium thiosulfate and calcium carbonate) were used to screen Sal‐monella and Shigella bacteria .Serum coagulation was performed by referring to the bacterial isolation situation over the years .The SPSS 18 .0 software was adopted to process the data .Then the difference in the separation rate of Salmonella and Shigella bacteria between the two different stool culture methods was compared .Results Totally 790 stool culture samples during 2013-2015 were included into the statistical analysis ,30 cases of Salmonella bacteria were isolated by adopting the routine method ,the positive rate was 3 .80% ;5 cases were Shigella bacteria ,the positive rate was 0 .63% ;but 77 cases of Salmonella bacteria were isolated by adop‐ting the modified TT enrichment broth method ,the positive rate was 9 .75% ,7 cases were Shigella bacteria ,the positive rate was 0 .89% ;the detection rate of Salmonella bacteria by adopting the modified TT enrichment broth method was 2 .57 times of the con‐ventional culture method ,which of Shigella bacteria was 1 .41 times ,showing that the difference of Salmonella and Shigella bacteria isolation between the two different methods had statistical significance(P<0 .05) .Conclusion The modified TT enrichment broth can significantly improve the positive isolation rate of Salmonella and Shigella stool culture ,which provides larger help for clinical doctor′s correct diagnosis and treatment of patients .

Comparação dos caldos selenito cistina, tetrationato Muller-Kauffmann e Rappaport-Vassiliadis no isolamento de Salmonella Typhimurium / Comparison of selenite cystine, tetrathionate Muller-Kauffmann and Rappaport-Vassiliadis broths for Salmonella Typhimurium isolation

Three selective enrichment broths - selenite cystine (SC), Muller-Kauffmann tetrathionate (MKT) and Rappaport-Vassiliadis (RV) - were compared, for Salmonella Typhimurium isolation from rectal swabs of a calf experimentally infected. The bacteriological procedure involved pre-enrichment in Hajna-GN broth (only for the samples inoculated in RV broth), selective enrichment (SC, MKT and RV broths), culture in modified brilliant green agar (BGA), presumptive biochemistry tests (using triple-sugar-iron agar and lysine-agar) and slide agglutination test with poli-O and poli-H Salmonella antisera. SC and MKT broths were more efficient in the isolation of Salmonella Typhimurium (12 positive samples), whereas RV broth had a lower efficiency in the microbiological isolation (ten positive samples).

Evaluation of PCR inhibitory effect of enrichment broths and comparison of DNA extraction methods for detection of Salmonella Enteritidis using real-time PCR assay

The best enrichment broth and DNA extraction scheme was determined for rapid and sensitive detection of Salmonella Enteritidis in steamed pork using real-time PCR. The inhibitory effect of commonly used Salmonella enrichment broths, Rappaport-Vassiliadis (RV) and Muller-Kauffmann tetrathionate with novobiocin (MKTTn), on real-time PCR was confirmed. The inhibition of PCR was statistically significant (p < 0.05) in RV and MKTTn, as compared with buffered peptone water (BPW) or phosphate-buffered saline. The inhibitory effect of the selective enrichment media was successfully removed by using a modified DNA extraction, PrepMan Ultra Reagent with an additional washing step or the DNeasy Tissue Kit. In three experiments, when applied to detection of Salmonella Enteritidis in steamed pork, the real-time PCR coupled with single 24 h enrichment with BPW performed better than double 48 h enrichment with BPW plus RV or MKTTn. The simple real-time PCR assay using BPW proved to be a rapid and sensitive test for detection of low concentrations of Salmonella Enteritidis in steamed pork samples as compared with the conventional culture method.

Compare of Selectivity Enrichment Broth for Detectable Effect of Listeria monocytogenes / 微生物学通报

This paper investigated contamination situation of Listeria monocytogenes(Lm). To compare dif- ferent selectivity enrichment broth for detectable effect of Lm and compare detectable effect in different samples by using different methods, furthermore, choose the best enrichment broth for specific food. One hundred and thirty five random samples from raw meat, aquatic product, fruit and vegetable, quick-frozen food in Baoding. Applied LB enrichment broth, EB enrichment broth, new modification FDA enrichment broth and Fraser enrichment broth before separated by PALCAM selective agar, then identified by interna- tional standard method after PCR. Results: Four methods showed that there were 23 Lm positive, detected 5 Lm by LB method, 6 Lm by Fraser method, 5 Lm by EB method and 7 Lm by new modification FDA method. The total detectable rate of four methods had no large specificity, but to specific kind of food was different.

Evaluation of a Rapid Enrichment-PCR Method for the Detection of vanA Vancomycin-resistant Enterococci in Fecal Specimens / 대한임상미생물학회지

BACKGROUND: Rapid and accurate surveillance is crucial in controlling vancomycin-resistant enterococci (VRE). Culture-based surveillance takes more than 4 days and direct polymerase chain reaction (PCR) is rapid but compromised by a low sensitivity. In this study, we evaluated the performance of an enrichment-PCR method for vanA VRE surveillance. METHODS: In July 2006, 100 fecal specimens were inoculated to Enterococcosel agar (EA) and Enterococcosel broth (EB) containing 6 microgram/mL vancomycin. After 1 or 2 day-incubation bacterial pellets were obtained from 1 mL of blackened EB and VanA PCR were performed with DNA extract of the pellets (EB+PCR). Blackened EB were also subcultured on EA (EB+EA). Black colonies on EA were submitted to identification and antimicrobial susceptibility test and, if necessary, they were confirmed with vanA PCR. The electronic medical records were reviewed for previous history of colonization or infection of VRE. RESULTS: A total of 59 specimens were positive for VRE by at least one method. VanA VRE was detected from 43, 54, and 53 specimens by EA, EB+ PCR, and EB+EA, respectively; 54 EB+PCR positive specimens comprised 43 EA-positive, 7 EA-negative/ EA+EB-positive and 4 EB+PCR-only-positive, and 11 EA-negative/EB+PCR-positive specimens were from the previous VRE-colonizers. The five EB+PCR-negative specimens were EB+EA-positive, suggesting false negativity, probably due to PCR inhibitors. The average turn-around time for EA was 88+/-35 h, whereas 98% of EB+PCR positive results were obtained at day 1. CONCLUSION: Enrichment in EB followed by PCR (EB+ PCR) appears to be a rapid and sensitive method for the detection of vanA VRE in stool specimens. Internal control would be required to detect false negative results.