A comparison of enrichment media for the isolation of salmonellae from seagull cloacal swabs.

The relative efficiency of three selective enrichment broths (Muller-Kauffmann tetrathionate. Rappaport''s and selenite F) was investigated for the isolation of salmonellae from seagull cloacal swabs. Pre-enrichment in buffered peptone water was employed throughout the study, which involved the examination of 560 gulls, sixty (10.7%) of which were found to be carrying salmonellae. Rappaport''s broth as modified by Vassiliadis for incubation at 43 degrees C (Vassiliadis et al. 1976) yielded the highest number of positive swabs (57) and the widest range of serotypes. It was significantly more efficient that either selenite F or tetrathionate broth, although the results obtained with Rappaport''s broth incubated at 37 and 43 degrees C did not differ significantly (P greater than 0.5). Eleven serotypes were isolated during the study, the most prevalent being Salmonella virchow.     

A comparison of procedures for the isolation of campylobacters from seagull faeces.

Two enrichment broths (Preston and Roman & Doyle''s) and four solid media (Preston, Skirrow''s, Butzler''s and Blaser''s) were compared to determine their relative efficiencies in recovering campylobacters from 389 freshly voided seagull faeces, 276 of which were found to contain campylobacters by one or more of the procedures used. A combination of enrichment in Preston medium followed by plating on to Preston agar gave the highest number of isolates (263). Enrichment in fluid media was shown to be an important part of the technique, as only 85 (30.8%) of the 276 isolations were made as a result of direct plating. Very little difference was seen between the two forms of enrichment (P greater than 0.5) but of the four selective media, Butzler''s was significantly less efficient than any of the other three (P less than 0.01), because it failed to grow more than a few strains of Campylobacter coli and the NARTC group, which together made up nearly two-thirds of the total number od Campylobacter spp. isolated.     

The effect of the use of different selective media on the ability to recover salmonellae from seagull faeces.

Solid media were compared for their ability to recover salmonellae from seagull faecal material after pre-enrichment in buffered peptone water and enrichment in Rappaport''s broth. Of the 847 specimens examined 96 were found to be positive for salmonellae. Use of Brilliant Green agar containing sulphamandelate supplement resulted in the detection of salmonellae from each of the 96 samples found to be positive and was the most efficient medium tested. Brilliant Green agar lacking the supplement was the least effective medium, salmonellae being isolated from only 80 samples using this medium. All of the media tested were shown to support the growth of a wide range of salmonella serotypes, although Salmonella typhi and S. dublin did not form colonies on those media which contained Brilliant Green. Hynes'' modification of deoxycholate citrate agar was shown to be considerably less inhibitory to salmonellae after ageing for four days. Ageing of other media had no significant affect on their ability to support the growth of salmonellae.     

沙门菌增菌培养基增菌效果的探讨与分析研究

〔目的〕选择好的商品增菌培养基 ,以提高沙门菌的检出率。〔方法〕用一定数量的大肠埃希菌与不同数量种类的沙门菌混合培养 ,观察不同增菌液的增菌效果。〔结果〕目前市售的沙门增菌培养基的增菌效果差距很大 ,差的只有在 1:10状况下沙门菌呈优势生长 ,好的可达 1:1× 10 8或以上状况下仍呈优势生长。〔结论〕自配的SC和TTB增菌液增菌效果最好。     

A comparison of two media for the isolation of campylobacter in the tropics

Two selective media for the isolation of campylobacter from the faeces have been compared. Both have a similar isolation rate, but Butzler's medium allows easier identification and sub-culturing of campylobacter than Skirrow's medium because it is more inhibitory to other faecal organisms. Butzler's medium is made with sheep blood which is usually more easily available in Africa, so for these reasons it may be a more suitable medium for use there.     

Detection of West Nile virus in oral and cloacal swabs collected from bird carcasses

We evaluated if postmortem cloacal and oral swabs could replace brain tissue as a specimen for West Nile virus (WNV) detection. WNV was detected in all three specimen types from 20 dead crows and jays with an average of >10(5) WNV PFU in each. These findings suggest that testing cloacal or oral swabs might be a low-resource approach to detect WNV in dead birds.     

A comparison of selected media and incubation temperatures for isolation of microscopic fungi from dried medicinal plants

The study compared selected media and incubation temperatures for isolation of fungi from dried medicinal plants (chamomile, peppermint, lemon balm, St. John's wort and two herbal mixtures). The DG18 medium was found to be the most suitable for characterization of the mycoflora at 25 degrees C. The medium selection for 37 degrees C was dependent on the species to be isolated. MEA + 40% sacharose and YpSs were found to be the best media for isolation of thermophilic and thermotolerant fungi from dried medicinal plants.     

Incubation at raised temperature or enrichment media, combined with secondary enrichment in Rappaport's medium, for the isolation of salmonellas from sewage.

Two FMDV strains which had been previously differentiated by complement-fixation were compared by guinea-pig protection test, kinetic neutralization and micro-neutralization tests. It was found that these tests, which have not been previously applied by the methods described, were all capable of FMDV STRAIN DIFFERENTIATION. Similar differences were found by all methods, which suggests that comparisons made by cross-CF, cross-neutr-alization or cross-protection involve measurement of the same antigen/antibody interactions.     

An evaluation of commercially available dehydrated Rappaport-Vassiliadis medium for the isolation of salmonellae from poultry

A total of 745 samples of chicken giblets was cultured to determine the relative efficiency of a commercially available Rappaport-Vassiliadis medium (RV-Oxoid). Experiments to determine the optimum inoculation ratio showed that 1:100 was superior to the other ratios tested. Comparison of RV-Oxoid with standard RV and RV-medium prepared using soya peptone (RV-soya) showed that after 24 h RV-soya was significantly better than RV-Oxoid (P less than 0.05), although there was no significant difference between standard RV and RV-Oxoid. Furthermore, when the duration of incubation was extended to 48 h there was no significant difference between the three media (P greater than 0.25). We conclude that RV-Oxoid is a satisfactory product for the isolation of salmonellae from poultry, providing that it is inoculated at a ratio of 1:100 and is incubated for 48 h. Its use can therefore be recommended to laboratories who wish to use a dehydrated medium.     

Evaluation of two enrichment broths, three plating media and ELISA technique for the isolation of salmonella from dairy products

Salmonella is one of the most important food-borne pathogens that can be transmitted through the consumption of contaminated milk and milk products. Early detection of Salmonella in food is important for food safety. Two selective media, brilliant green agar (BGA) and xylose lysine desoxycholate (XLD) agar are commonly used in diagnostic laboratories for the isolation of Salmonella, often after enrichment of the samples in a broth before plating on the solid medium. Recently, a new medium called CHROmagar Salmonella (CAS) has become available for the rapid detection of Salmonella. In the present study, we compared this new medium with BGA and XLD for the isolation of Salmonella from 160 dairy products samples (80 ice cream and 80 kariesh cheese samples) with enrichment in Rappaport- Vassiliadis (RV) and tetrathionate (TT) broth. TECRA Unique Salmonella ELISA test was used. Only one sample was positive for Salmonella, which appeared on each of CAS and XLD agars, after enrichment using RV but not TT. This was associated with a sensitivity and specificity of (100 %, 92.45%), (100%, 93.71%) and (0 %, 100%) for each of CHROmagar Salmonella, XLD and BGA respectively. TECRA Unique Salmonella test yielded the highest sensitivity and specificity among all used methods; it had 100% sensitivity with 100% specificity.     

An evaluation of commercially available dehydrated Rappaport-Vassiliadis medium for the isolation of salmonellae from poultry.

A total of 745 samples of chicken giblets was cultured to determine the relative efficiency of a commercially available Rappaport-Vassiliadis medium (RV-Oxoid). Experiments to determine the optimum inoculation ratio showed that 1:100 was superior to the other ratios tested. Comparison of RV-Oxoid with standard RV and RV-medium prepared using soya peptone (RV-soya) showed that after 24 h RV-soya was significantly better than RV-Oxoid (P less than 0.05), although there was no significant difference between standard RV and RV-Oxoid. Furthermore, when the duration of incubation was extended to 48 h there was no significant difference between the three media (P greater than 0.25). We conclude that RV-Oxoid is a satisfactory product for the isolation of salmonellae from poultry, providing that it is inoculated at a ratio of 1:100 and is incubated for 48 h. Its use can therefore be recommended to laboratories who wish to use a dehydrated medium.     

A comparison of the original Rappaport medium (R medium) and the Rappaport-Vassiliadis medium (RV medium) in the isolation of salmonellae from meat products.

The Rappaport-Vassiliadis enrichment medium (RV medium) in 10 ml quantities (RV/43 degrees C, 10 ml) inoculated with 0.1 ml of pre-enrichment medium (P medium) was found more efficient in the isolation of salmonellae from 409 pre-enriched samples (mainly meat products), than the original Rappaport medium incubated at 43 degrees C (R/43 degrees C) and the RV medium in 5 ml quantities (RV/43 degrees C, 5 ml) inoculated with 0.01 ml of P medium (P less than 0.001, in both instances). Therefore, the inoculum from pre-enriched foods should not be less than 0.1 ml in 10 ml of RV medium. The RV/43 degrees, 10 ml was also better (P less than 0.01) in detecting samples containing salmonellas than the original Rappaport medium incubated at 37 degrees C (R/37 degrees C, 10 ml) and the modification R25 of R medium incubated at 37 degrees C. The R25 modification was used in 10 ml quantities (R25/37 degrees C, 10 ml) inoculated with 0.1 ml of P medium and in 5 ml quantities (R25/37 degrees, 5 ml) inoculated with 0.01 ml of P medium. The last two R25 procedures were of the same efficiency in isolating salmonellas from meat products.