沙门氏菌Ⅲb的一个新血清型

An enterobacterium culture, S3188, providing with Salmonella biological characteristics, except exhibiting indole positive reaction, was isolated from the intestinal content of reptile a snake. It utilized malonate, did not ferment dulcitol, it attacked lactose promptly, and ONPG positive. H antigens appeared diphasic. By cross agglutination and absorption tests, it was demonstrated that the antigenic formula of this strain is 53:1, Z13:e, n,(Z15)... It was found to be a new serotype of Salmonella IIIb.     

Molecular fingerprinting of Salmonella serotype Glostrup

Thirteen isolates of Salmonella serotype Glostrup (antigenic formula, 6.8:z10:e,n,z15) from various sources and countries were analysed by ribotyping and IS200 fingerprinting. Both methods provided a high index of strain discrimination by allowing detection of three ribotypes and eight IS200 fingerprints which, though generally related, were readily distinguishable. The findings of this analysis confirm the usefulness of ribotyping and IS200 fingerprinting for studying the epidemiology of rarely isolated salmonellae of serogroup C.     

Enzymatic synthesis of polyprenyl phosphosugars in Salmonella serotype C1

The cell envelopes of serogroup C1 Salmonella, viz. S. thompson and S. montevideo, catalyze the transfer of radiolabeled sugars from UDP-[14C]Glc and UDP-[14C]GlcNAc into the lipid-linked sugars. Using TLC and DEAE-cellulose chromatography, the radiolabeled products were identified as polyprenyl pyrophosphate N-acetylglucosamine (I), polyprenyl monophosphate N-acetylglucosamine and polyprenyl monophosphate glucose. The derivative (I) served as an acceptor for mannose transfer from GDP-Man with formation of Man1-2GlcNAc1PPPre. A similar reaction was observed after addition of synthetic GlcNAc1PPPre to the cell envelopes.     

Detection and characterisation of integrons in Salmonella enterica serotype enteritidis

Integrons have been widely described among the Enterobacteriaceae including strains of multi-resistant Salmonella enterica serotype Typhimurium DT104; however, information with respect to the presence of integrons among S. enterica serotype Enteritidis strains is limited. Multi-resistant isolates of Enteritidis were screened for the presence of integrons using a PCR protocol. One integron was detected in all isolates that were resistant to sulfonamide and streptomycin. Characterisation of these isolates indicated an integron which ranged in size between 1000 and 2000 bp and which harboured a gene cassette encoding the ant(3")-Ia gene specifying streptomycin and spectinomycin resistance. Further studies revealed the integrons to be located on large conjugative plasmids. This appears to be the first report of plasmid-borne integrons in Enteritidis.     

RosE represses Std fimbrial expression in Salmonella enterica serotype Typhimurium

The Salmonella enterica serotype Typhimurium ( S. typhimurium ) genome contains a large repertoire of putative fimbrial operons that remain poorly characterized because they are not expressed in vitro . In this study, insertions that induced expression of the putative stdABCD fimbrial operon were identified from a random bank of transposon mutants by screening with immuno-magnetic particles for ligand expression (SIMPLE). Transposon insertions upstream of csgC and lrhA or within dam , setB and STM4463 (renamed rosE ) resulted in expression of StdA and its assembly into fimbrial filaments on the cell surface. RosE is a novel negative regulator of Std fimbrial expression as indicated by its repression of a std :: lacZ reporter construct and by binding of the purified protein to a DNA region upstream of the stdA start codon. Expression of Std fimbriae in the rosE mutant resulted in increased attachment of S. typhimurium to human colonic epithelial cell lines (T-84 and CaCo-2). A rosE mutant exhibited a reduced ability to compete with virulent S. typhimurium for colonization of murine organs, while no defect was observed when both competing strains carried a stdAB deletion. These data suggest that a tight control of Std fimbrial expression mediated by RosE is required during host pathogen interaction.     

Heterogeneity of persistence of Salmonella enterica serotype Senftenberg strains could explain the emergence of this serotype in poultry flocks

Salmonella enterica serotype Senftenberg (S. Senftenberg) has recently become more frequent in poultry flocks. Moreover some strains have been implicated in severe clinical cases. To explain the causes of this emergence in farm animals, 134 S. Senftenberg isolates from hatcheries, poultry farms and human clinical cases were analyzed. Persistent and non-persistent strains were identified in chicks. The non-persistent strains disappeared from ceca a few weeks post inoculation. This lack of persistence could be related to the disappearance of this serotype from poultry farms in the past. In contrast, persistent S. Senftenberg strains induced an intestinal asymptomatic carrier state in chicks similar to S. Enteritidis, but a weaker systemic infection than S. Enteritidis in chicks and mice. An in vitro analysis showed that the low infectivity of S. Senftenberg is in part related to its low capacity to invade enterocytes and thus to translocate the intestinal barrier. The higher capacity of persistent than non-persistent strains to colonize and persist in the ceca of chickens could explain the increased persistence of S. Senftenberg in poultry flocks. This trait might thus present a human health risk as these bacteria could be present in animals before slaughter and during food processing.     

Salmonella serotype typhimurium phage typing. A critical evaluation

Of 12,930 Salmonella serotype typhimurium strains, phage typed during 1985-1988, 45.68% were "nontypable" by Anderson's set; the percent of typable strains decreased from 54.17 in 1986 to 30.54 in 1988. Of 90 phage patterns of sensitivity, 22 were currently encountered. Phage types 1, 18 and 104 were most frequent to strain of both human and non-human origin. In food generating S. typhimurium outbreaks, phage types 1 and 36 were prevalent. Except lysotypes 198 and 95, isolated from "single cases" in man only, all other phage types were common in man and animals, too. Introducing other typing methods to serotype typhimurium "nontypable" strains (by Anderson's set) was considered necessary for epidemiological purposes.     

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.