Clinical salmonellosis in a guinea pig colony caused by a new Salmonella serotype, Salmonella ochiogu

During a severe outbreak of clinical salmonellosis in an experimental guinea pig colony, a new strain of Salmonella was isolated and identified. The new serotype, with the antigenic structure 1,3,19 : Z38 : e, n, Z15, for which the name Salmonella ochiogu has been suggested, caused both enteric and systemic infection in the animal colony. During the outbreak a total of 127 animals died (26.9%). All ages of animal were affected. Treatment with oral tetracycline was successful when combined with strict hygienic measures.     

Two Additional Salmonella Serotypes: Salmonella enteritidis Ser 58:a:- and Salmonella enteritidis Ser 44Z36, Z38:-

The antigenic compositions of two additional Salmonella serotypes isolated from the feces of man were determined to be 58:a:- and 44:Z(36), Z(38)-.     

沙门氏菌Ⅲb的一个新血清型

1989年8月从蛇肠内容物中检出一株沙门氏菌,编号为S.3337经鉴定为新血清型,其生化特性符合沙门氏菌属的定义.根据该菌株不发酵卫矛醇,能利用丙二酸盐,迅速发酵乳糖,ONPG为阳性,具有双相H抗原,应归属于沙门氏菌Ⅲb.经抗原分析该菌株的抗原式为65:z:z_(55).     

An immunoblotting as a method for the diagnosis of typhoid fever

The patients' sera had been referred to the National Salmonella Centre for routine Widal serology. Sera were predominately from patients suspected of having been infected with Salmonella Typhi, but also included one serum from patient with typhoid fever who was culture positive for Salmonella Typhi. The immunoblotting procedure using Salmonella Typhi somatic (O=9,12 LPS) and flagellar (H=d) antigens was used for preliminary testing of selected patients sera previously evaluated by Widal agglutination assay as containing different levels of antibodies against O and/or H antigens of Salmonella Typhi. Following Chart et al., immunoblotting reactions were graded between 0 and 3, with 0 indicating an absence of antibody binding, and 3 where antibody binding was readily observed. Sera giving reaction of 2 or 3 were considered to be antibody positive for this study. Positive immunoblotting reaction to O=9,12 LPS antigen was obtained only with the serum of patient with typhoid fever. Presence of specific anti-LPS antibodies was also observed in two other patients' sera diluted 1:50, and in case of one of them also in dilution 1:200, but intensity of antigen-antibody reaction was under positive result criterion. The most other sera positive to O=9,12 antigen in law dilutions (1:50, 1:100) by Widal assay, showed the traces of non-specific reaction by immunoblotting. Presence of positive antigen-antibody reaction was indicated for five sera in dilution 1:50 when tested with the >55 kDa H=d flagellar protein subunit, including the serum of patient with typhoid fever. Only in this serum the high level of specific antibodies was detected also in dilution 1:200, what was not observed in case of the other four, which appeared negative. All the other sera were shown not to contain antibodies to flagella antigen. Although the presented results are preliminary and additional study of more sera of people infected with Salmonella Typhi is needed, it can be concluded after Chart et al., that an immunoblotting procedure incorporating O=9,12 LPS and flagellar H=d antigens is a useful method for providing serological evidence of infection with Salmonella Typhi. In our opinion it can serve as a rapid test for the diagnosis of typhoid fever.     

Microbial population profiles of the microflora associated with pre- and postharvest tomatoes contaminated with Salmonella typhimurium or Salmonella montevideo

Aims:  To determine the microflora profiles of pre- and postharvest tomatoes contaminated with Salmonella montevideo or S. typhimurium DT104.
Methods and Results:  Salmonella montevideo or S. typhimurium was inoculated onto the flowers of tomato plants with the microflora of the subsequent fruit examined using a combination of Source Carbon Utilization and 16S rDNA-PCR profiling. From 16S rDNA profiles it was evident that tomatoes derived from Salmonella inoculated plants harboured a different microbial population compared to nontreated controls. The same result was observed for tomatoes inoculated at postharvest and subsequently stored for 14 days at 15°C. From sequencing analysis it was found that tomatoes derived from Salmonella inoculated plants but testing negative for the enteric pathogen, frequently harboured Enterobacter and Bacillus spp. In contrast, both bacterial types were not found associated with tomatoes testing positive for Salmonella.
Conclusions:  Salmonella introduced onto tomatoes at pre- or postharvest alters the composition of the microbial community. The presence of Enterobacter and Bacillus spp negatively affects the persistence of Salmonella on preharvest tomatoes.
Significance and Impact of the Study:  Salmonella appears to modify rather than become integrated into the microbial communities associated with tomatoes. Yet, the presence of antagonistic bacteria appears to reduce the persistence of the enteric pathogen.     

Detection of Campylobacter jejuni and Salmonella typhimurium in chicken using PCR for virulence factor hipO and invA genes (Saudi Arabia)

Campylobacter jejuni and Salmonella typhimurium are the leading causes of bacterial food contamination in chicken carcasses. Contamination is particularly associated with the slaughtering process. The present study isolated C. jejuni and S. typhimurim from fifty chicken carcass samples, all of which were acquired from different companies in Riyadh, Saudi Arabia. The identification of C. jejuni was performed phenotypically by using a hippurate test and genetically using a polymerase chain reaction with primers for 16S rRNA and hippurate hydrolase (hipO gene). For the dentification of S. typhimurim, a serological Widal test was carried out using serum anti-S. typhimurium antibodies. Strains were genetically detected using invA gene primers. The positive isolates for C. jejuni showed a specific molecular size of 1448 bp for 16S rRNA and 1148 bp for hipO genes. However, the positive isolates of the invA gene exhibited a specific molecular size at 244 bp using polymerase chain reaction (PCR). Comparing sequencing was performed with respect to the invA gene and the BLAST nucleotide isolates that were identified as Salmonella enterica subsp. enterica serovar typhimurium strain ST45, thereby producing a similarity of 100%. The testing identified C. jejuni for hippuricase, GenBank: {"type":"entrez-nucleotide","attrs":{"text":"Z36940.1","term_id":"535805"}}Z36940.1. While many isolates of Salmonella spp. that contained the invA gene were not necessarily identified as S. typhimurim, the limiting factor for the Widal test used antiS. typhimurum antibodies. The multidrug resistance (MDR) of C. jejuni isolates in chickens was compared with the standard C. jejuni strain ATCC 22931. Similarly, S. typhimurium isolates were compared with the standard S. typhimurium strain ATCC 14028.     

Application of an automated immunomagnetic separation-enzyme immunoassay for the detection of Salmonella spp during an outbreak associated with a retail premises

AIMS: The application of an automated immunomagnetic separation-enzyme immunoassay (AIMS-EIA) during the investigation of a suspected outbreak of Salmonella food poisoning at a retail premises. METHODS AND RESULTS: Six food samples and 24 environmental swabs were taken from the retail premises and six food handlers' submitted faecal samples during the investigation of the outbreak. Isolation and identification of Salmonella from these samples was performed according to established standard operating procedures and by AIMS-EIA. Twelve of the 18 (67%) Salmonella culture positive samples were AIMS-EIA positive on testing pre-enrichment samples after 24 h, whilst 17 (94%) samples were AIMS-EIA positive following selective enrichment for a further 48 h. One food handler was found to be positive for Salmonella by both culture and AIMS-EIA. All Salmonella isolates were confirmed as Salmonella Enteritidis phagetype 21c. CONCLUSIONS: The AIMS-EIA protocol compliments the conventional culture approach to produce more timely results for the management of the risk to public health without significantly increasing the workload of the laboratory. SIGNIFICANCE AND IMPACT OF THE STUDY: The food production premise investigated in this study was heavily contaminated with Salmonella Enteritidis. Application of the AIMS-EIA was significant in the effective intervention of control measures for the protection of public health.     

Evaluation of new culture media for rapid detection and isolation of salmonellae in foods.

Conventional methods for Salmonella detection in foods can require up to 6 and at least 4 days. We have observed that the total analysis time can be reduced to 48 h by using Salmosyst broth as a liquid medium for both preenrichment and selective enrichment and Rambach agar (RA), a new selective plate medium. In samples of artificially contaminated ground beef Salmonella enteritidis was detected at a concentration of 0.4 CFU/g (10 CFU/25 g) by both a conventional method and the new method. Of 519 samples of foods for sale, 38 were Salmonella positive by both methods while 471 were negative. Nine samples which were negative by the conventional method were positive by the Salmosyst-RA method, while one sample positive by the first method was negative by the last. Therefore, the Salmosyst-RA method showed 97.9% sensitivity compared with the 81.2% sensitivity of the conventional method. The new method was also highly specific (98% specificity) in presumptive identification of Salmonella colonies. Furthermore, a 6-h preenrichment in Salmosyst broth has been proved sufficient for the repair of heat-injured Salmonella cells and for subsequent recovery by selective enrichment. In conclusion, the Salmosyst-RA method shows several advantages over both conventional and rapid noncultural methods: (i) only two media are required instead of the five media for conventional methods; (ii) in real time it is comparable to other rapid noncultural methods, which require 30 to 31 h; (iii) it is highly sensitive and specific; and (iv) it allows the isolation of Salmonella strains which can be characterized by appropriate phenotypic and genotypic typing methods for epidemiological investigations.     

Adding a selective enrichment step to the iQ-Check real-time PCR improves the detection of Salmonella in naturally contaminated retail turkey meat products

AIMS: The aim of this study was to compare the real-time iQ-Check Salmonella kit (Bio-Rad) with the immunocapture assay RapidCheck Salmonella method, and a conventional culture method (FSIS, USDA) in detecting Salmonella in naturally contaminated turkey meat products. This study was also designed to determine if a selective enrichment step might improve the real-time detection of Salmonella. METHODS AND RESULTS: Using the culture method, Salmonella was recovered from 49 out of 99 retail turkey meat samples collected. RapidCheck failed to detect 11 Salmonella samples that were positive by the culture method. The iQ-Check real-time PCR also failed to detect three samples that were positive by the culture method. However, when carried out after a selective enrichment step, the iQ-Check real-time PCR detected all 49 Salmonella samples recovered by the culture method. The iQ-Check real-time PCR detected the presence of Salmonella in some samples that were not recovered by the culture method. CONCLUSIONS: Adding a selective enrichment step to the iQ-Check real-time PCR improves the detection of Salmonella in naturally contaminated turkey meat samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The iQ-Check Salmonella real-time PCR can be used as a rapid method to monitor Salmonella in turkey meat, together with conventional culture methodology.     

Phage-typing ofSalmonella panama according to the method of Craigie and Yen

A phage-typing scheme forSalmonella panama has been established. This was done according to the method of Craigie and Yen by means of phage preparations which are all derived from a single phage. So far, eight phage types and a restgroup Z could be demonstrated by means of phage 47 and seven adaptations derived from it.