Assessment of beef carcass contamination with Salmonella and E. coli O 157 in slaughterhouses in Bishoftu, Ethiopia

Background Salmonella and E. coli O157 are common causes of foodborne diseases. Evisceration and de-hiding steps can lead to carcass contamination during slaughter operation. In Ethiopia, information on the association between the presence of these pathogens in the rectal content and/or on the hide of cattle and their presence on the carcass is lacking. Methods The aim of this study was to assess the sources of beef carcass contamination with Salmonella and E. coli O157 during slaughter. Rectal contents and hide- and carcass-swabs (from three sites: foreleg, brisket and hind leg) were collected from 70 beef cattle at two small scale slaughterhouses. Isolates were genotyped by the Pulsed Field Gel Electrophoresis method and tested for resistance against 14 microbial drugs. Results Salmonella was detected at equal proportions (7.1%) in rectal content samples and hide swabs. E. coli O157 was detected in 8.6% of the rectal contents and 4.3% of the hide swabs. The proportion of contaminated carcasses was 8.6% for Salmonella and 7.1% for E. coli O157. Genetic linkage between the Salmonella and E. coli O157 isolates from the rectal contents and/or hides and carcasses were observed only in a few cases (2 and 1 carcasses, respectively) indicating the limited direct transfer of the pathogens from the feces and/or hide to the carcass during slaughter. Most carcasses became positive by cross contamination. All the S. Typhimurium isolates (n = 8) were multidrug resistant being resistant to ampicillin, chloramphenicol, sulfamethoxazole and tetracycline. The two S. Dublin isolates were resistant to colistin. All E. coli O157 isolates were susceptible to the antimicrobials tested. Conclusion The results indicated that cross contamination may be an important source for carcass contamination.

Concentrated Bioshell Calcium Oxide (BiSCaO) Water Kills Pathogenic Microbes: Characterization and Activity

Bioshell calcium oxide (BiSCaO) exhibits deodorizing properties and broad microbicidal activity. In this study, we examined possible utility of BiSCaO Water for that purpose. BiSCaO Water was prepared by adding 10 wt% BiSCaO to clean water and gently collecting the supernatant in a bottle. The same volume of clean water was gently poured onto the BiSCaO precipitate and the supernatant was gently collected in a bottle; this process was repeated fifty times. The produced BiSCaO Water contained nanoparticles (about 400–800 nm) composed of smaller nanoparticles (100–200 nm), and was colorless and transparent, with a pH > 12.7. In vitro assays demonstrated that BiSCaO Water eliminated more than 99.9% of influenza A (H1N1) and Feline calicivirus, Escherichia coli such as NBRC 3972 and O-157:H7, Pseudomonas aeruginosa, Salmonella, and Staphylococcus aureus within 15 min. We compared BiSCaO Water with the other microbicidal reagents such as ethanol, BiSCaO, BiSCa(OH)2 suspensions, povidone iodine, NaClO, BiSCaO dispersion and colloidal dispersion with respect to deodorization activity and microbicidal efficacy. The results showed that BiSCaO Water was a potent reagent with excellent deodorization and disinfection activities against pathogenic bacteria and viruses (including both enveloped and nonenveloped viruses).

Seaweed Extracts Effectiveness against Selected Gram-negative Bacterial Isolates

Aqueous and six solvent extracts of four seaweeds Codium tomentosum (Chlorophyceae); Corallina mediterranea, Hypnea musciformis (Rhodophyceae), and Sargassum vulgare (Phaeophyceae) were screened for their antibacterial activity against 10 gram-negative bacterial isolates. Seaweeds crude extracts potent antibacterial activity have been evaluated based on zone of inhibition (ZI), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values as reported in manyresearches. Overall, aqueous algal extracts were non active against all tested isolates regardless examined seaweed species. It was noticed that ZIs were in the following order: S. vulgare (17 mm) against Acinetobacter baumannii and C. mediteranea (17 mm) against Salmonella typhimurium > H. musciformis (13 mm) against Escherichia coli O:157 > C. tomentosum (11 mm) against S. typhimurium. Data revealed that the S. vulgare extracts showed the most inhibitory activity by showing the lowest MIC50 value of 0.08 mg/mL (methanolic extract against Shigella flexneri and hexane extract against E. coli O:157 isolate) and also the lowest MBC value of 1.00 mg/mL (methanolic extract against S. typhimurium, Serratia marcescens, E. coli O:157 and Brucella melitensis isolates; and also with ethanolic extract against S. marcescens and E. coli O:157 isolates). Future studies on the S. vulgare extracts are required due to their importance as a potent, promising and cheap source of bioactive compounds for antibacterial pretreatment.

Clinical Evaluation and Cost Analysis of Great Basin Shiga Toxin Direct Molecular Assay for Detection of Shiga Toxin-Producing Escherichia coli in Diarrheal Stool Specimens

ABSTRACTThe Shiga Toxin Direct molecular assay (ST Direct) relies on nucleic acid amplification and solid array-based amplicon detection to identify Shiga toxin-producingEscherichia coli(STEC) in preserved stool specimens. Genes encoding Shiga toxin (stx1andstx2), as well as theE. coliserotype O:157-specific markerrfbE, are simultaneously detected within 2 h. ST Direct was evaluated using 1,084 prospectively collected preserved stool specimens across five clinical centers. An additional 55 retrospectively collected, frozen specimens were included to increase the number of positive specimens evaluated. Results were compared to results from routine culture and an enzyme immunoassay (EIA) specific for the recovery and identification of STEC. ST Direct was found to be 93.2% sensitive and 99.3% specific for detection ofstx1andstx2and 95.7% sensitive and 99.3% specific for detection ofE. coliserotype O:157. All specimens with false-positive results were found to containstx1orstx2or were found to be positive for serotype O:157 when analyzed using alternative molecular methods. All 4 false-negativestx1orstx2results were reported for frozen, retrospectively tested specimens. In all cases, the specimens tested positive forstxby an alternative FDA-cleared nucleic acid amplification test (NAAT) but were negative forstx1andstx2following nucleic acid sequence analysis. Based on these data, culture and EIA-based methods for detection of STEC are only 33% sensitive compared to molecular tests. A retrospective cost analysis demonstrated 59% of the cost of routine stool culture to be attributable to the identification of STEC. Taken together, these data suggest that ST Direct may provide a cost-effective, rapid molecular alternative to routine culture for the identification of STEC in preserved stool specimens.

Investigations on Prevalence and Antimicrobial Resistance of Enterohaemorrhagic Escherichia Coli (Ehec) Among Dairy Farms in the North Part of the Republic of Bulgaria

Over a 2-year period, from January 2011 to May 2013, a total of 1094 faecal swab samples were collected from cattle at different age at 4 farms in North Bulgaria: Okorsh, Slavyanovo (Popovo municipality), Dobri dol and Trem. Out of them, 36 coli strains (3.3%) positive in the E. coli O:157 antiserum agglutination test and identified by the BBL CRYSTAL identification system as belonging to the E. coli O:157 serotype were isolated. The distribution of isolates was as followed: 5 (0.5%) E. coli O:157 strains at the Okorsh dairy cattle farm, 7 (0.6%) E. coli isolates at the Slavyanovo dairy farm, 16 (1.5%) isolates at the Dobri dol farm and 8 (0.7%) isolates at the Trem farm. Colibacteria exhibited 100% sensitivity to oxyimino-cephalosporins, gentamicin and enrofloxacin, and were resistant to ampicillin (19.4%) and tetracycline (41.6%). From the 15 strains resistant to tetracycline, 11 were isolated from the cows at Dobri dol, while the other 4 originated from the other three farms. The 7 ampicillin-resistant E. coli isolates were detected only at the Dobri dol cattle farm.