Search results for "ENTEROBACTERIACEAE"
showing 10 items of 143 documents
Pathogenic microorganisms carried by migratorybirds passing through the territory of the island ofUstica, Sicily (Italy)
2011
Several studies have shown that migratory birds play an important role in the ecology, circulation and dissemination of pathogenic organisms. In October 2006, a health status evaluation was performed on a large population of migratory birds passing through the territory of Ustica (Italy), an island located on the migration route of many species of birds to Africa, and various laboratory tests were conducted. In total, 218 faecal swabs and the internal organs of 21 subjects found dead in nets were collected for bacteriological and virological examination, including avian influenza and Newcastle disease. In addition, 19 pooled fresh faecal samples were collected for mycological examination. T…
Recovery Estimation of Dried Foodborne Pathogens Is Directly Related to Rehydration Kinetics.
2016
International audience; Drying is a common process which is used to preserve food products and technological microorganisms, but which is deleterious for the cells. The aim of this study is to differentiate the effects of drying alone from the effects of the successive and necessary rehydration. Rehydration of dried bacteria is a critical step already studied in starter culture but not for different kinetics and not for pathogens. In the present study, the influence of rehydration kinetics was investigated for three foodborne pathogens involved in neonatal diseases caused by the consumption of rehydrated milk powder: Salmonella enterica subsp. enterica serovar Typhimurium, Salmonella enteri…
Strong influence of the exposure medium on mutagenicity in the Ames test: 7-methylbenz[a]anthracene-5,6-oxide.
1991
We have previously shown that the activity of the ionized mutagen, 1-hydroxmethylpyrene sulphate, is strongly enhanced in Salmonella typhimurium TA98, when KCl is present in the exposure medium (50-fold at a concentration of 125 mM KCl) and that the halogen ion is responsible for this effect. Here we show that KCl has the opposite effect on the activity of the lipophilic mutagen, 7-methylbenz[a]anthracene-5,6-oxide, (10-fold decrease at a concentration of 125 mM) and that K+ accounts for this influence. Many other solutes also decreased the mutagenicity of 7-methylbenz[a]anthracene-5,6-oxide, but to a smaller extent than the K+ salts. The stability of 7-methylbenz[a]anthracene-5,6-oxide did…
Proliferative response of synovial fluid and peripheral blood mononuclear cells to arthritogenic and non-arthritogenic microbial antigens and to the …
1990
Cellular immune responses to microbial antigens have been implicated in the pathogenesis of some forms of arthritis including reactive arthritis, Reiter's syndrome, ankylosing spondylitis and rheumatoid arthritis. We investigated the proliferative T cell responses of paired peripheral blood (PB) and synovial fluid (SF) mononuclear cells (MC) to so-called arthritogenic bacteria (Yersinia enterocolitica and Salmonella typhimurium), to control antigens, such as Candida albicans, mumps virus and purified protein derivative, to the recombinant mycobacterial 65-kDa heat-shock protein (hsp 65) and the mitogen phytohemagglutinin (PHA) in 16 patients with different inflammatory rheumatic diseases. T…
Mutagenicity of N-substituted phenanthrene 9,10-imines in Salmonella typhimurium and Chinese hamster V79 cells.
1986
We previously showed that some (nonsubstituted) aziridines derived from polycyclic aromatic hydrocarbons (arene imines) elicit various mutagenic and genotoxic effects in bacteria and mammalian cells and that these arene imines are active at much lower concentrations than the corresponding epoxide analogues. In the present study, N-substituted derivatives of phenanthrene 9,10-imine were investigated. All 10 derivatives studied showed direct mutagenicity in Salmonella typhimurium TA100. Some of the compounds additionally exhibited weak effects in the strains TA98 and TA1537. Most N-substituted derivatives were weaker mutagens than unsubstituted phenanthrene 9,10-imine but stronger mutagens th…
Microbial contamination of milk and dairy products from restaurants in Spain
2009
This study was carried out to evaluate the microbiological quality of milk and some dairy products, including 95 lots of warm milk, 95 lots of milk conserved at room temperature, and 75 lots of dairy products collected from restaurants in Spain. According to the European microbiological criteria (92/46/EEC, 93/43/EEC, and Commission Regulation No. 2073/2005), 31% and 35% of the total examined lots exceed the adopted limits of mesophilic aerobic counts and Enterobacteriaceae, respectively. This may be due to incorrect handling of milk and dairy products and inadequate cleaning and sanitization of milk container. Further, 2% of all the lots examined were positive for the presence of Escherich…
Siderophore production by environmental strains ofSalmonellaspecies
1989
Iron uptake mechanisms were investigated in different species of Salmonella isolated from environmental waters. All strains examined were able to grow in the presence of high concentrations (10 mM) of the iron chelator EDDA. All strains excreted phenolate and hydroxamate siderophores, as assessed by bioassays and chemical tests. Bioassays with different indicator strains showed that all Salmonella strains can cross-feed other Enterobacteria, as well as mutants of Salmonella typhimurium deficient in the Enterobactin system, suggesting that this siderophore may be produced by the environmental Salmonella strains. The siderophore aerobactin may also be produced by one of the strains, according…
A single method for recovery and concentration of enteric viruses and bacteria from fresh-cut vegetables
2011
Fresh-cut vegetables are prone to be contaminated with foodborne pathogens during growth, harvest, transport and further processing and handling. As most of these products are generally eaten raw or mildly treated, there is an increase in the number of outbreaks caused by viruses and bacteria associated with fresh vegetables. Foodborne pathogens are usually present at very low levels and have to be concentrated (i.e. viruses) or enriched (i.e. bacteria) to enhance their detection. With this aim, a rapid concentration method has been developed for the simultaneous recovery of hepatitis A virus (HAV), norovirus (NV), murine norovirus (MNV) as a surrogate for NV, Escherichia coli O157:H7, List…
Improved acid tolerance of a recombinant strain of Escherichia coli expressing genes from the acidophilic bacterium Oenococcus oeni.
2001
Aims:Oenococcus oeni is a lactic acid bacterium used in wine fermentation. Two open reading frames (orfB and orfC) were identified in the upstream region of the hsp18 gene, encoding the small heat-shock protein Lo18. Expression of these genes in conditions of acid stress was studied in Escherichia coli. Methods and Results: Sequence analysis showed that orfB encodes a putative transcriptional regulator of the LysR family. The protein encoded by orfC shares homologies with multi-drug resistance systems. Heterologous expression of orfB, orfC and hsp18 genes in Escherichia coli significantly enhanced the viability of the host strain under acidic conditions. Conclusions: It was demonstrated tha…
Salmonella serovars identified at the centre for enterobacteriaceae of palermo over the 5-year period 1983-87
1990
Salmonellosis is become an increasing public health problem in many countries. Serotyping and assessment of antibiotic resistance are useful tools, which assist in understanding the epidemiology of Salmonella infections. In this respect, the Centre of Enterobacteriaceae of Southern Italy provides helpful information on the changing pattern of Salmonella serovars in this geographic area. This paper reports the distribution of serovars and their antibiotic susceptibility in the years 1983-1987. In particular, because of their peculiar trends during this 5-year period, epidemiological features of Mbandaka, Corvallis, Dublin, Infantis and Wien serovars are described.