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At least 109 records · Page 6Linked to original sources
PubMed2006

Isolation and characterization of the emerging foodborn pathogen Arcobacter from human stool.

At present, isolation of arcobacters from human specimens is performed by slightly of not modified Campylobacter, Yersinia or Leptospira isolation techniques, and knowledge if arcobacters are part of the human commensal flora is lacking. Therefore, an Arcobacter selective isolation procedure was validated for the examination of human fecal specimens, and the presence and characteristics of Arcobacter in feces of asymptomatic humans was examined in order to assess the clinical relevance of arcobacters in diarrheal stool. With this method, Arcobacter was isolated from seven of 500 (1.4%) stool samples of healthy people with Arcobacter cryaerophilus as the only species present. Seven A. cryaerophilus genotypes were detected and only one genotype was found per person. Neither A. butzleri nor A. skirrowii were isolated, therefore the presence of those latter species in clinical samples requires further attention. Though the pathogenic role and potential virulence factors of arcobacters have to be further examined, the current status of arcobacters as emerging pathogens remains justified.

Adult↗
PubMed2003

Activity of dermaseptin K4-S4 against foodborne pathogens.

Dermaseptin S4 and its substituted derivative K(4)-S4 were investigated against various food-related pathogenic bacteria in culture media. K(4)-S4, but not the native peptide displayed significant growth inhibitory activity against all bacteria tested. Next, activity of K(4)-S4 against Escherichia coli O157:H7 was defined in terms of milieu dependencies. Salt-dependent kinetic studies in growth medium indicated that the peptide's antibacterial activity is maintained at fairly high (up to 600mM) NaCl concentrations but inhibited at higher concentrations. Similarly, antibacterial activity was reduced at high but not low pH conditions. Importantly, antibacterial activity was significantly maintained at temperatures lower than 37 degrees C and significantly enhanced at 42 degrees C. With respect to bactericidal kinetics, negative cultures were obtained in LB as well as in commercial apple juice, respectively, within 1 and 2h treatment, at twice the minimal inhibitory concentration (MIC) value. Overall, the data collected is indicative of a certain interest for dermaseptin derivatives as potential food preservatives.

Amino Acid Substitution↗
PubMed2002

Foodborne pathogenic bacteria in prepackaged fresh retail portions of farmed rainbow trout and salmon stored at 3 degrees C.

Twelve lots of fresh unskinned fillets of rainbow trout (Oncorhynchus mykiss) and 10 lots of fresh sliced salmon (Salmo salar) prepacked in trays wrapped with an oxygen-permeable film were obtained immediately after packing from two supermarkets having in-plant facilities for packaging wet fish. During storage at 3 degrees C, Listeria innocua was detected in eight lots of trout fillets after 4 days storage. L. monocytogenes was recovered from a single lot also contaminated with L. innocua. Initial numbers of aeromonads were significantly (p < 0.05) lower in trout fillets (3.35 +/- 0.62 log cfu g(-1)) than in salmon slices (4.20 +/- 0.89 log cfu g(-1)). In both fish products, these bacteria significantly (p < 0.05) increased up until spoilage. Most Aeromonas spp. isolates from trout fillets were assigned to A. veronii biovar sobria HG8 (hybridisation group 8), A. caviae HG4, A. eucrenophila HG6, A. hydrophila HG1 and A. veronii biovar veronii HG10. Strains of HG12 (A. schubertii), HG4 and HG8 formed the majority of aeromonads recovered from salmon slices.

Aeromonas↗
PubMed2003

The survival of foodborne pathogens during domestic washing-up and subsequent transfer onto washing-up sponges, kitchen surfaces and food.

In this study, the survival of Salmonella, Campylobacter and Escherichia coli O157: H7, when exposed to a range of constant temperatures (47-60 degrees C), in hard or soft water, in the presence/absence of detergent (0-0.3%) and organic matter, and during drying, was investigated. Further experiments used a washing-up process simulation, where soiled dishes contaminated with bacteria were washed in a bowl of warm water containing detergent. In addition, this study considered the risk of bacterial transfer onto (1) sterile dishes and sponges via contaminated water, (2) kitchen surfaces wiped with a contaminated sponge, (3) items placed in direct contact with a contaminated kitchen surface, (4) food placed on a contaminated dish or (5) dishes from contaminated food. A proportion of dishes remained contaminated with all pathogen types after a typical washing-up. Water hardness did not appear to affect survival. E. coli, and to a lesser extent Salmonella, survived towel- or air-drying on dishes and after towel-drying the cloth became contaminated on every occasion, regardless of the test organism. A proportion of sterile dishes washed after contaminated dishes became contaminated with pathogens but transfer from dishes onto food was rare. Washing-up sponges frequently became contaminated with pathogens. The results of this study highlight the potential for survival and cross contamination of food borne pathogens in the kitchen environment.

Campylobacter↗
PubMed2003

Survival of foodborne pathogens on stainless steel surfaces and cross-contamination to foods.

The retention of bacteria on food contact surfaces increases the risk of cross-contamination of these microorganisms to food. The risk has been considered to be lowered when the surfaces are dry, partly because bacterial growth and survival would be reduced. However, some non-spore-forming bacteria might be able to withstand dry conditions on surfaces for an extensive period of time. In this study the survival of Salmonella enteritidis, Staphylococcus aureus and Campylobacter jejuni on stainless steel surfaces at different initial levels was determined at room temperature. The transfer rates of these pathogens from kitchen sponges to stainless steel surfaces and from these surfaces to foods were also investigated. Staph. aureus was recovered from the surfaces for at least 4 days when the contamination level was high (10(5) CFU/cm2) or moderate (10(3) CFU/cm2). At low levels (10 CFU/cm2), the surviving numbers decreased below the detection limit (4 CFU/100 cm2) within 2 days. S. enteritidis was recovered from surfaces for at least 4 days at high contamination levels, but at moderate level, the numbers decreased to the detection limit within 24 h and at low level within 1 h. C. jejuni was the most susceptible to slow-air-drying on surfaces; at high contamination levels, the numbers decreased below the detection limit within 4 h. The test microorganisms were readily transmitted from the wet sponges to the stainless steel surfaces and from these surfaces to the cucumber and chicken fillet slices, with the transfer rates varied from 20% to 100%. This study has highlighted the fact that pathogens remain viable on dry stainless steel surfaces and present a contamination hazard for considerable periods of time, dependent on the contamination levels and type of pathogen. Systematic studies on the risks of pathogen transfer associated with surface cleaning using contaminated sponges provide quantitative data from which a model of risks assessment in domestic setting could lead.

Bacterial Adhesion↗
PubMed2004

Viability loss and morphology change of foodborne pathogens following exposure to hydrostatic pressures in the presence and absence of bacteriocins.

Cell suspensions of three pathogens were exposed to hydrostatic pressure (HP), bacteriocin mixture (nisin and pediocin) or a combination of HP+bacteriocins and changes in colony forming units (cfu) and cell-morphology by scanning electron microscopy (SEM) were studied. Cell viability loss, as determined from the reduction in cfu before and after a treatment, occurred in Listeria monocytogenes by all three treatments and in Salmonella typhimurium and Escherichia coli O157:H7 by HP and HP+bacteriocin combination. Cell wall and cell membrane collapse and cell lysis was indicated in L. monocytogenes exposed to bacteriocin or HP+bacteriocin and in Salmonella and E. coli exposed to HP or HP+bacteriocin.

Anti-Bacterial Agents↗
PubMed2003

Induction of an adaptive tolerance response in the foodborne pathogen, Campylobacter jejuni.

In this study we aimed to determine if Campylobacter had the ability to induce an adaptive tolerance response (ATR) to acid and/or aerobic conditions. Campylobacter jejuni CI 120 was grown to the appropriate phase in Brucella broth under microaerobic conditions. Cells were initially adapted to a mild stress (pH 5.5) for 5 h prior to challenge at pH 4.5, a lethal pH. Survival was examined by determining the numbers of viable cells on Campylobacter blood free selective agar base. Stationary phase cells adapted at pH 5.5 induced an ATR that enabled a 100-fold greater survival compared to an uninduced culture. Aerobic adaptation also protected the cells against acid challenge. The cross protection provided a 500-fold increase in survival when compared to unadapted cells. The incorporation of chloramphenicol during the induction period eliminated the ATR and resulted in death kinetics similar to an uninduced culture. These data suggest that Campylobacter spp. have the ability to induce an ATR to sublethal treatments, which increased their ability to withstand subsequent stresses.

Adaptation, Physiological↗
PubMed2004

Simultaneous and sensitive detection of three foodborne pathogens by multiplex PCR, capillary gel electrophoresis, and laser-induced fluorescence.

The simultaneous detection of Staphylococcus aureus, Listeria monocytogenes, and Salmonella spp. has been approached by a new multiplex PCR-based procedure followed by capillary gel electrophoresis with laser-induced fluorescence detection (multiplex-PCR-CGE-LIF). As compared to slab gel electrophoresis, the use of CGE-LIF improved from 10- to 1000-fold the sensitivity of the multiplex PCR analysis, allowing the detection of 2.6 x 10(3) cfu mL(-1) of S. aureus, 570 cfu mL(-1) of L. monocytogenes, and 790 cfu mL(-1) of Salmonella in artificially inoculated food, without enrichment. Following 6 h of enrichment, as low as 260, 79, and 57 cfu mL(-1) of S. aureus, L. monocytogenes, and Salmonella, respectively, were detected. The CGE-LIF method is shown to be reproducible, providing relative standard deviation (RSD) values lower than 0.8% for analysis time and lower than 5.8% for peak areas. The multiplex-PCR-CGE-LIF proved a powerful analytical tool to detect various food pathogens simultaneously in a fast, reproducible, and sensitive way.

Electrophoresis, Capillary↗
PubMed2000

Activity of hydrolysed lactoferrin against foodborne pathogenic bacteria in growth media: the effect of EDTA.

Lactoferrin was hydrolysed with pepsin and the antimicrobial activity of the resulting hydrolysate (HLF) was studied in 1% peptone, 0.05% yeast extract, 1% glucose (PYG) medium and tryptic soy broth (TSB). HLF was effective against Listeria monocytogenes, enterohaemorrhagic Escherichia coli and Salmonella enteritidis in PYG, however, the highest studied concentration (1.6 mg ml-1) did not inhibit growth of any of these organisms in TSB. The addition of EDTA enhanced the activity of HLF in TSB, indicating that the decreased activity of HLF may have been due, in part, to excess cations in the medium.

Animals↗
PubMed2000

Prospects for 'competitive exclusion' treatment to control salmonellas and other foodborne pathogens in poultry.

In newly hatched chicks, the rapid establishment of an adult-type intestinal microflora, via the oral route, produces almost immediate resistance to colonization by any food poisoning salmonellas that gain access to the rearing environment. Exploitation of the 'competitive exclusion' (CE) effect is now an accepted part of the overall strategy by which poultry-associated salmonellas are being controlled in some countries. This review covers practical aspects of CE treatment and factors affecting efficacy in both laboratory-scale trials and field studies. It also considers possible applications in preventing colonization of poultry with Escherichia coli O157 and Campylobacter jejuni. For the latter, evidence suggests that the 'protective' organisms are different from those involved in salmonella control.

Animal Husbandry↗
PubMed1996

Emerging foodborne pathogens: Escherichia coli O157:H7 as a model of entry of a new pathogen into the food supply of the developed world.

There would appear to be little argument that the large outbreaks of E. coli O157:H7 which have occurred since the early 1980s represent a distinct, new phenomenon. The number of reported cases have increased dramatically, starting from zero in 1981; however, it is also clear that this increase in reported cases is in part an artifact of improved surveillance and reporting. Available data suggest that E. coli O157:H7 infections were present prior to 1982, although numbers appear to have been small. At a molecular level, the organism shows evidence of clonal origin, but there is not the striking clonality, with virtually identical pulsed-field gel electrophoresis and ribotyping patterns, which has been seen in situations such as the emergence of Vibrio cholerae O139 Bengal in the Indian subcontinent in 1992 or the introduction of V. cholerae O1 into naïve populations in South America in 1991 (127-129). Findings are more consistent with the image of an organism which arose from a common ancestor, but which has had time to become distributed geographically and to show some evidence of genetic divergence. While this is an "emerging" infection, at least in terms of its distribution and public recognition, it is unlikely that it will be possible to identify the "first" O157:H7 case or to track the clonal spread of the organism through cattle or human populations.

Animals↗
PubMed2005

Alternatives to antibiotics: utilization of bacteriophage to treat colibacillosis and prevent foodborne pathogens.

Bacteriophages are viruses that infect and kill bacteria. Bacteriophage do not infect animal and plant cells, which makes them a potentially safe alternative to antibiotics. We have been conducting research on the efficacy of bacteriophage to prevent and treat colibacillosis in poultry. Bacteriophages that were lytic to a non-motile, serotype 02 isolate of Escherichia coli were isolated from municipal wastewater treatment plants and poultry processing plants. This E. coli isolate is pathogenic to poultry, causing severe respiratory and systemic infections. Two bacteriophage isolates were selected for use in studies designed to determine the efficacy of these bacteriophage to prevent and treat severe colibacillosis in poultry. Colibacillosis was induced by injecting 6 x 10(4) cfu of E. coli into the thoracic air sac when birds were 1 wk of age. Initial studies demonstrated that mortality was significantly reduced from 85 to 35% when the challenge culture was mixed with equal titers of bacteriophage, and the birds were completely protected when the challenge culture was mixed with 10 pfu of bacteriophage. In subsequent studies, we have shown that an aerosol spray of bacteriophage given to birds prior to this E. coli challenge could significantly reduce mortality even when given 3 d prior to the E. coli challenge. Our research on treating colibacillosis in poultry has demonstrated that an intramuscular injection of bacteriophage given 24 or 48 h after the birds were challenged rescued the birds from this severe E. coli infection. We have demonstrated that bacteriophage can be used to prevent and treat colibacillosis in poultry and may provide an effective alternative to antibiotic use in animal production.

Animal Feed↗
PubMed2006

Environmental survival mechanisms of the foodborne pathogen Campylobacter jejuni.

Campylobacter spp. continue to be the greatest cause of bacterial gastrointestinal infections in humans worldwide. They encounter many stresses in the host intestinal tract, on foods and in the environment. However, in common with other enteric bacteria, they have developed survival mechanisms to overcome these stresses. Many of the survival mechanisms used by Campylobacter spp. differ from those used by other bacteria, such as Escherichia coli and Salmonella spp. This review summarizes the mechanisms by which Campylobacter spp. adapt to stress conditions and thereby increase their ability to survive on food and in the environment.

Adaptation, Physiological↗