Listeria monocytogenes in poultry and poultry products: epidemiological investigations in seven Danish abattoirs

Listeria monocytogenes was isolated from 11/236 (4·7%) caecal samples from parent flocks, providing broilers to the abattoirs investigated. Caecal samples from 2078 broilers representing 90 randomly selected broiler flocks were negative for L. monocytogenes. A total of 3080 samples from seven abattoirs including poultry processing line samples, and final products were also examined for L. monocytogenes. Listeria monocytogenes was isolated in 0·3% to 18·7% of the samples collected in the different abattoirs. Epidemiological typing of 247 L. monocytogenes isolates, including serotyping, phage typing, pulsed-field gel electrophoresis and ribotyping revealed 62 different clones. Based upon typability and discriminatory power, DNA typing methods used were found equally suitable as epidemiological markers. Serotyping and phage typing were not found useful as epidemiological markers for poultry isolates of L. monocytogenes since only 120/247 (48·6%) isolates were typable by phage typing and 230/247 (93·1%) L. monocytogenes belonged to serotype 01 while 6/247 (2·4%) belonged to 04. The discovery of a few dominating clones in each abattoir might indicate an endemic occurrence of L. monocytogenes. It is concluded that L. monocytogenes in the broiler production is primarily localized to the abattoirs. The incidence of L. monocytogenes may be reduced by improving the hygiene.     

The effect of leucotriene C4 and D4 on cutaneous blood flow in humans

Using a laser-Doppler-flowmeter the microvascular response to LTC₄ and LTD₄ was measured. Intradermal injection of 1 Ug LTC₄ and LTD₄ caused an increase in the microvascular cutaneous bloodflow. The increase in flow was equal to that caused by histamine in equimolar amounts. Blocking the triple-response did not change the response. The values measured after injection of histamine and leucotrienes were about 10–15 times the values found in undisturbed skin and represents probably a maximally dilated vascular bed. Injection of the leucotrienes caused a slight sensation of pain.     

Bronchial hyperreactivity to leucotriene D4 and histamine in exogenous asthma.

Reactivity of the small and large airways to inhaled leucotriene D4, one of the leucotrienes that constitute slow reacting substance of anaphylaxis, was studied in eight patients with exogenous asthma and nine healthy subjects with no history of atopy. Non-cumulative dose response relations were constructed for leucotriene D4 in a randomised, double blind set up. Reactivity to the leucotriene was compared with reactivity to histamine in the two groups. Both groups reacted to leucotriene D4 with significant airway obstruction evident in forced expiratory volume in one second (FEV1), peak expiratory flow rate, maximal expiratory flow rate at 30% of forced vital capacity estimated from a partial flow volume curve initiated at 50% of vital capacity (V30), and an increase in volume of trapped gas. The airways of the patients were significantly (p less than 0.01) more reactive to leucotriene D4 than those of the controls. The differences were in order of magnitude, 10(2)-10(3) for FEV1 but only about 15 for V30 (p less than 0.05). The hyperreactivity of the airways of the asthmatic subjects to leucotriene D4 was comparable to that to histamine. Inhalation of leucotriene D4 caused pronounced dyspnoea only among the patients. The findings suggest a role for leucotriene D4 in human bronchial asthma.     

Serotonin(4) (5-HT(4)) receptor agonists are putative antidepressants with a rapid onset of action

Current antidepressants are clinically effective only after several weeks of administration. Here, we show that serotonin(4) (5-HT(4)) agonists reduce immobility in the forced swimming test, displaying an antidepressant potential. Moreover, a 3 day regimen with such compounds modifies rat brain parameters considered to be key markers of antidepressant action, but that are observed only after 2-3 week treatments with classical molecules: desensitization of 5-HT(1A) autoreceptors, increased tonus on hippocampal postsynaptic 5-HT(1A) receptors, and enhanced phosphorylation of the CREB protein and neurogenesis in the hippocampus. In contrast, a 3 day treatment with the SSRI citalopram remains devoid of any effect on these parameters. Finally, a 3 day regimen with the 5-HT(4) agonist RS 67333 was sufficient to reduce both the hyperlocomotion induced by olfactory bulbectomy and the diminution of sucrose intake consecutive to a chronic mild stress. These findings point out 5-HT(4) receptor agonists as a putative class of antidepressants with a rapid onset of action.     

Real‐time PCR detection of Enterococcus faecalis associated with amyloid arthropathy

Aims: To develop a RT‐PCR method for detection of the multilocus sequence type 82 of Enterococcus faecalis associated with amyloid arthropathy (AA) in layers. Methods and Results: Bacteria were selected from lesions including AA in layers. The primers were designed based on the phosphate ATP binding cassette transporter (pstS) and xanthine phosphoribosyltransferase (xpt) genes and first tested against three isolates with known base pairs at the specific sites. Subsequently, 12 isolates were selected from our collection by one researcher, and RT‐PCR was performed blinded. The sequence type (ST) was then confirmed by multilocus sequence analysis. Two single‐nucleotide polymorphisms in the pstS and xpt genes allowed an unambiguous identification of ST82. As an alternative to DNA extraction, a boiling method for release of DNA from cells was used. Conclusions: The real‐time PCR targeting ST82 enables rapid screening of Ent. faecalis cultured from suspect cases with results available after a few hours, much faster than multilocus sequence typing and pulse field gel electrophoresis. Significance and Impact of the Study: The new method allows a rapid screening of isolates with results available after only few hours. This RT‐PCR method could be a useful tool for molecular epidemiological studies on the spread of arthropathic and amyloidogenic Ent. faecalis within and between birds more efficiently.     

Sensory, chemical and bacteriological changes during storage of iced squid (Todaropsis eblanae)

AIMS: To relate sensory shelf-life of iced whole and gutted squid to bacterial growth and chemical changes. METHODS AND RESULTS: Cooked mantles from whole and gutted individuals were rejected after 10 and 12 days of storage, respectively, due to ammoniacal off-odours. Rate of production of both ammonia and trimethylamine was highest in the whole lot. Agmatine, which was only present in trace amounts in freshly-caught squid, increased rapidly in both lots. The main microflora at the time of sensory rejection of iced whole squid included Gram-negative, motile and non-fermentative rods, which were psychrophilic and had a requirement for NaCl. 16S rDNA sequence analyses identified the strains as belonging to the genus Pseudoalteromonas. Shewanella putrefaciens, Pseudoalteromonas sp. and Pseudomonas sp. dominated in spoiled gutted squid. Identification of strains from the stomach and digestive gland of recently-captured squid showed that the main flora consisted of Photobacterium phosphoreum. CONCLUSIONS: Spoilage of iced squid is likely to result from a combination of autolytic and bacterial changes. Agmatine seems to be an excellent freshness indicator. Photobacterium phosphoreum may contribute to spoilage through activity in the digestive gland, followed by diffusion of volatile compounds and amines to the mantle. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to the psychrophilic nature of P. phosphoreum and Pseudoalteromonas sp., spread-plating and low temperature incubation are recommended for bacteriological evaluation of iced squid.     

Cross-contamination with Salmonella on a broiler slaughterhouse line demonstrated by use of epidemiological markers

AIMS: To investigate contamination of surfaces on a poultry slaughter line from infected poultry and subsequent cross-contamination of non-infected poultry. METHODS AND RESULTS: A broiler slaughterhouse was investigated for the presence of Salmonella on 17 defined points over two 1-week periods. Flocks supplied to slaughter and neck skin samples from processed chicken were likewise investigated. Salmonella was detected in 10 out of 18 flocks at ante-mortem inspection, while seven flocks tested positive in the finished products. Equipment at all but one control point at the slaughter line tested positive at least once during the study. The chicken receiving area was the most contaminated. By comparison of typing results from serotyping, plasmid profile typing and phage typing, direct evidence for cross-contamination with Salm. serotype Typhimurium, Salm. Serotype 4.12:b:- and Salm. serotype Virchow on the slaughter line was obtained for four of the flocks. The cleaning procedure in place did not remove all Salmonella from the contaminated areas. CONCLUSIONS: Evidence for contamination of equipment on a slaughter line and subsequent cross-contamination to non-infected chicken was provided by typing methods. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has provided detailed information on cross-contamination on a slaughter line by the use of phage typing and plasmid profiling. The study stresses the importance of controlling Salmonella in the primary production, as contamination of the equipment on the slaughter line will act as a vehicle to contaminate finished products. Cleaning procedures on slaughter lines cannot be expected to control this problem with the current equipment.     

Analysis of gene order data supports vertical inheritance of the leukotoxin operon and genome rearrangements in the 5' flanking region in genus <Emphasis Type="Italic">Mannheimia</Emphasis>

Background  

The Mannheimia subclades belong to the same bacterial genus, but have taken divergent paths toward their distinct lifestyles. For example, M. haemolytica + M. glucosida are potential pathogens of the respiratory tract in the mammalian suborder Ruminantia, whereas M. ruminalis, the supposed sister group, lives as a commensal in the ovine rumen. We have tested the hypothesis that vertical inheritance of the leukotoxin (lktCABD) operon has occurred from the last common ancestor of genus Mannheimia to any ancestor of the diverging subclades by exploring gene order data.