Comparison of Campylobacter fla-SVR genotypes isolated from humans and poultry in three European regions

Aims:  The genetic diversity of Campylobacter isolated from human infection and from poultry was assessed in strains originating in three different European regions in order to compare these two hosts and to investigate European regional differences.
Methods and Results:  Randomly chosen isolates originated from Norway, Iceland and Basque Country in Spain were genotyped by sequencing of the short variable region (SVR) of flaA . A total of 293 strains were investigated, c . 100 per country with half originated from either host. The results indicate extensive diversity in both hosts and identified differences in the nature and distribution of genotypes between the countries. These differences could in part be related to geographical location, in that Campylobacter genotypes from Iceland and Norway were more similar to each other than either was to Basque Country.
Conclusions:  Differences between the countries exceeded the observed differences between human and poultry isolates within a country.
Significance and Impact of the Study:  Regional differences are extensive and should not be ignored when comparing genotyping data originating from different international studies.     

Plantaricin 163对热杀索丝菌的抗菌活性及其作用机制

【背景】热杀索丝菌(Brochothrix thermosphacta)为鲫鱼在4°C贮藏过程中的主要腐败菌,Plantaricin 163是由植物乳杆菌产生的一种新型广谱细菌素,能明显延长鲫鱼的贮藏期。【目的】研究Plantaricin163对热杀索丝菌的抗菌活性和作用机制。【方法】通过测定最小抑菌浓度(Minimuminhibitoryconcentration)和杀菌动力学了解Plantaricin163对热杀索丝菌的抗菌效果,并从电导率的变化、核酸和蛋白的泄露、流式细胞实验、扫描电镜和透射电镜观察等4个方面探讨Plantaricin 163对热杀索丝菌的作用机制。【结果】Plantaricin 163对热杀索丝菌的的最小抑菌浓度为32μg/mL,优于Nisin的作用效果,作用方式为杀菌模式,6 h内能完全杀死热杀索丝菌。Plantaricin163能够通过增加热杀索丝菌细胞膜的通透性,增加胞外电导率,进而破坏细胞膜完整性,导致内容物泄漏,并影响细胞的外部形态和内部结构,从而导致菌体细胞瓦解死亡。【结论】Plantaricin 163可以破坏热杀索丝菌的细胞膜和内部结构,发挥抗菌活性。     

Genetic characterization and antibiotic resistance of Campylobacter spp. isolated from poultry and humans in Senegal

AIMS: The main objectives of this study were to investigate the diversity of Campylobacter genotypes circulating in Senegal and to determine the frequency of antibiotic resistance. METHODS AND RESULTS: Strains of Campylobacter jejuni isolated from poultry (n = 99) and from patients (n = 10) and Campylobacter coli isolated from poultry (n = 72) were subtyped by pulsed-field gel electrophoresis (PFGE). The pulsotypes obtained after digestion by SmaI and KpnI revealed a significant genetic diversity in both species, but without any predominant pulsotypes. However, farm-specific clones were identified in the majority of poultry houses (76.5%). Human and poultry isolates of C. jejuni had common PFGE patterns. High quinolone-resistance rates were observed for C. jejuni (43.4%) and C. coli (48.6%) isolates obtained from poultry. CONCLUSIONS: The results showed a genetic diversity of Campylobacter between farms indicating multiple sources of infection; but specific clones had the ability to colonize the broiler farms. The antimicrobial resistance patterns were not related to any specific PFGE pattern suggesting that resistance was due to the selective pressure of antibiotic usage. Campylobacter with similar genotypes were circulating in both human and poultry. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is important for the understanding of the epidemiology of Campylobacter in broiler farms in Senegal. It also emphasizes the need for a more stringent policy in the use of antimicrobial agents in food animals.     

A capillary polymerase chain reaction for Salmonella detection from poultry meat

AIMS: In this study, a capillary polymerase chain reaction (cPCR) was applied for Salmonella detection from poultry meat. METHODS AND RESULTS: Salmonella detection limits of the optimized cPCR were determined with DNA templates from the samples of tetrathionate broth (TTB), Rappaport Vassiliadis broth (RVB) and selenite cystine broth (SCB) artificially contaminated with 10-fold dilutions of 6 x 10(8) CFU ml(-1) of pure Salmonella enterica ssp. enterica serovar Enteritidis 64K stock culture. Detection limits of cPCR from TTB, RVB and SCB were found as 6, 6 x 10(1) and 6 x 10(4) CFU ml(-1), respectively. In addition, detection limits of bacteriology were also determined as 6 CFU ml(-1) with TTB and SCB, and 6 x 10(1) CFU ml(-1) with RVB. A total of 200 samples, consisting of 100 chicken and 100 turkey meat samples, were tested with optimized cPCR and bacteriology. Eight and six per cent of the chicken meat samples were found to harbour Salmonella by cPCR and standard bacteriology, respectively. Of six Salmonella isolates, four belonged to serogroup D, two to serogroup B. CONCLUSIONS: The TTB cultures of both artificially and naturally contaminated samples were found to be superior to those of RVB and SCB cultures in their cPCR results. This cPCR, utilizing template from 18-h TTB primary enrichment broth culture, takes approximately 40 min in the successful detection of Salmonella from poultry meat. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that cPCR from TTB enrichment culture of poultry meat would enable rapid detection of Salmonella in laboratories with low sample throughput and limited budget.     

Genotypic characteristics of a Mycobacterium sp. isolated from yellowtail Seriola quinqueradiata and striped jack Pseudocaranx dentex in Japan

In Japan, a Mycobacterium marinum‐like mycobacterium was isolated from the yellowtail, Seriola quinqueradiata. The species was identified as M. marinum by a commercial mycobacterial DNA‐DNA hybridization kit. Nevertheless, PCR restriction analysis of the DNA of its RNA polymerase β‐subunit gene definitively showed that this Mycobacterium sp. was M. ulcerans. PCR analysis revealed the genotypic characteristics of M. ulcerans in the Mycobacterium sp., only the mup053 gene sequence being absent, as has been found previously in other piscine mycobacteria such as M. marinum strains DL240490 and DL045 and M. pseudoshottsii. With one exception, this Mycobacterium sp. and M. pseudoshottsii had identical 16S rRNA gene sequences, which is also probably true of M. marinum strains DL240490 and DL045. Similarly, according to comparisons of the 16S rRNA gene, ITS region, and hsp65 gene sequences, this Mycobacterium sp. is more closely related to M. pseudoshottsii than to M. ulcerans or M. marinum. A PCR product of approximately 2000 bp was amplified from region of difference 9 in the Mycobacterium sp. The nucleotide sequence revealed insertion of IS2404, the sequence of which is 1366 bp long. The novel single nucleotide polymorphisms identified in this region distinguished this Mycobacterium sp. from M. marinum strain DL240490 and M. pseudoshottsii. The present findings raise the possibility that these species have a common ancestor. Further studies are required to improve our understanding of the relationship between their geographical origin and genetic diversity.     

Penetration of poultry meat byPseudomonas andLactobacillus spp.

The penetration of poultry muscle strips byPseudomonas putida, P. fragi, Lactobacillus plantarum andL. casei was studied at 37°C. The first three bacteria penetrated along the muscular septa whileLactobacillus casei did not invade the poultry muscle strips at all. The penetration by both pseudomonads occurred throughout the 3 cm muscle strip butL. plantarum showed minor penetration up to 2 cm only.     

Photobacterium carnosum sp. nov., isolated from spoiled modified atmosphere packaged poultry meat

Analysis of spoilage-associated microbiota of modified-atmosphere packaged poultry meat revealed four different bacterial isolates that could not be assigned to known species. They showed a Gram-negative staining behavior, were facultatively aerobic, non-motile with variable cell morphology. Phylogenetic analysis of 16S rDNA and gyrB, rpoD and recA revealed a distinct lineage within the genus Photobacterium with Photobacterium (P.) iliopiscarium DSM 9896^T, P. phosphoreum DSM 15556^T, P. kishitanii DSM 19954^T, P. piscicola LMG 27681^T and P. aquimaris DSM 23343^T as closest relatives.The designated type strain TMW 2.2021^T is non-luminous and grew at 0–20 °C (optimum 10–15 °C), within pH 5.0–8.5 (optimum 6–8) and in the presence of 0.5–3% (w/v) NaCl (optimum 1%). Major cellular fatty acids of TMW 2.2021^T were summed feature 3 (C_16:1ω7c/iso-C₁₅ 3-OH), C_16:0, C_18:1ω7c and summed feature 2 (C_12:0 aldehyde and C_10.928 unknown). Quinone analysis revealed Q-8 as sole respiratory ubiquinone. The genome of TMW 2.2021^T has a size of 4.56 Mb and a G + C content of 38.49 mol%. The ANI value between TMW 2.2021^T and the type strain of closest relative P. iliopiscarium DSM 9896^T was 91.43%. Fingerprinting on the base of M13-RAPD-PCR band pattern and MALDI-TOF MS profiles allowed intraspecies differentiation between our isolates but also supported their distinct lineage to a novel species. Based on phylogenetic, genomic, phenotypic and chemotaxonomic data, strain TMW 2.2021^T and further strains represent a novel species of the genus Photobacterium, for which the name Photobacterium carnosum sp. nov. is proposed. The type strain is TMW 2.2021^T (=DSM 105454^T = CECT 9394^T).     

Molecular identification of Salmonella isolates from poultry and meat productsin Irbid City,Jordan

The sensitivity and accuracy of molecular diagnosis of Salmonella from meat and poultry products using polymerase chain reaction (PCR) was compared with conventional microbiological methods. A total of 212 samples representing the most frequently used fresh and frozen meat and poultry products (whole, cut, ground, and processed) were collected from different locations within the city of Irbid. DNA was extracted directly from each food sample and amplified using Salmonella-specific primers. Samples were also analysed using conventional microbiological methods for the presence of Salmonella spp. Results showed that Salmonella was detected in 185 samples out of 212 (87%) by PCR technique, while 172 (81%) samples were detected Salmonella positive by conventional microbiological methods. On the other hand, 27 (12.7%) samples were negative by PCR and 40 (18.8%) samples were negative by conventional microbiological methods. PCR assay proved to be an effective method for Salmonella detection in meat and poultry products with high specificity and sensitivity and more importantly a less time-consuming procedure. Using PCR, Salmonella spp. detection could be achieved within 24–36 h compared to 3–8 days for the conventional microbiological methods.     

Inhibition of Brochothrix thermosphacta and sensory improvement of tropical peeled cooked shrimp by Lactococcus piscium CNCM I‐4031

Aims: To investigate the antimicrobial spectrum of Lactococcus piscium CNCM I‐4031 and its protective effect in cooked and peeled shrimp against Brochothrix thermosphacta. Methods and Results: Sixteen pathogenic and spoiling bacteria were inhibited in Elliker, but not in shrimp juice agar plates. In shrimp packed under modified atmosphere and stored at 8°C, B. thermosphacta (10³ CFU g^?1) was inhibited by 4·1 log CFU g^?1 when co‐inoculated with L. piscium (10⁶ CFU g^?1). Brochothrix thermosphacta spoiled the product after 11 days, with the emission of strong butter/caramel off‐odours. In co‐culture with L. piscium, sensory shelf‐life was extended by at least 10 days. The inhibition was partially explained by a drop in pH from 6·6 to 5·6. The physicochemical composition of shrimp and shrimp juice was established to identify the inhibition mechanisms involved. Conclusion: Lactococcus piscium CNCM I‐4031 has a wide antimicrobial spectrum. The strain inhibits B. thermosphacta in shrimp and significantly prolongs sensory shelf‐life. Significance and Impact of the Study: Lactococcus piscium CNCM I‐4031 is shown to be a promising agent for improving shrimp quality and may be tested against pathogens and in other food matrices. Knowledge of the physicochemical composition of shrimp and shrimp juice will allow the development of a chemically defined model medium for determining the inhibition mechanisms involved.     

Identification and characterization of Carnobacteria isolated from fish intestine

Eleven bacterial strains were isolated from the gastrointestinal tract of four fish species, Atlantic salmon (Salmo salar L.), Arctic charr (Salvelinus alpinus L.), Atlantic cod (Gadus morhua L.) and wolffish (Anarhichas lupus L.). All the strains were Gram-positive rods, non-sporing, catalase and oxidase-negative, able to grow at pH 9.0 but not on acetate containing media (pH < or = 5.4), and were fermentative. They had a high content of oleic acid (18:1 n-9) in cellular lipid, and were found to belong to the genus Carnobacterium by phenotypic criteria. The eleven carnobacteria strains were further identified on the basis of 16S rDNA sequence analysis and AFLP(TM) fingerprinting.     

Comparison of Vibrio spp. populations found in seawater, in exhibition aquaria, in fish intestine and in fish feed

Aims:  Vibrio populations in the seawater supply and the water of seven exhibition aquaria that simulate various Mediterranean and tropical ecosystems were compared. The similarity of Vibrio populations in the intestine of various fish species, feed and water was examined. Resistance to the antibiotics used in fish health management was analysed for the dominant Vibrio isolates.
Methods and Results:  Samples were collected for 1 year from seven exhibition tanks reproducing different ecosystems. The diversity and population similarity among vibrios were determined using a miniaturized biochemical phenotyping method. Similar Vibrio populations were found in the water supply and in the water of the Mediterranean ecosystems. However, different Vibrio populations were found in the water of tanks with tropical ecosystems. Vibrio populations in the water seemed to have a greater effect on the composition of intestinal Vibrio populations than those in feed. No resistance to antibiotics was observed, indicating their appropriate use for health management.
Conclusions:  Water characteristics have a greater impact on the composition of Vibrio populations in aquaria and fish intestinal microbiota than bacteria in feed.
Significance and Impact of the Study:  The microbiological monitoring water could provide valuable information for managing the health of exhibition aquaria.     

Functional,antioxidant and antibacterial properties of protein hydrolysates prepared from fish meat fermented by Bacillus subtilis A26

Composition, functional properties and in vitro antioxidant and antibacterial activities of protein hydrolysates prepared with a proteolytic bacterium, Bacillus subtilis A26, through fermentation of fish proteins were investigated. Fermented fish meat protein hydrolysates (FPHs) were prepared from sardinelle (SPH), zebra blenny (ZPH) goby (GPH) and ray (RPH). The protein content of freeze-dried FPHs ranged from 74.3% to 81%. All fermented hydrolysates had an excellent solubility and possessed interfacial properties. The antioxidant activities of FPHs were evaluated by different methods, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay, β-carotene bleaching and DNA nicking assay. All hydrolysates showed dose-dependent antioxidant activities. Further, FPHs exhibited antibacterial activity and SPH was the most effective, particularly against Gram positive bacteria.     

Isolation from poultry litter and characterization [corrected] of Staphylococcus spp. capable of growth in high phosphate conditions [corrected

AIMS: To isolate and characterize micro-organisms from poultry litter capable of growing under phosphate concentrations typical of poultry litter. METHODS AND RESULTS: Poultry litter extracts were plated onto brain-heart infusion medium (BHI) containing an additional 0.75 mol l(-1) phosphate (BHI-P). Colonies were screened for the presence of inclusion granules with five being selected for further study. All strains displayed identical biochemical characteristics consistent with Staphylococcus spp. and grouped with Staphylococcus spp. by comparative 16S rDNA analysis. Thus all five strains were identified as such. All strains displayed elevated intracellular phosphate levels when cultured in BHI-P broth (0.417-0.600 microg phosphate mg(-1) protein) vs BHI broth (0.075-0.093 microg phosphate mg(-1) protein). When grown using an austere semi-defined medium or BHI-P, Staph. sp. #7 displayed similar elevated intracellular phosphate levels compared with growth in BHI. CONCLUSIONS: Poultry litter contains novel Staphylococcus spp. capable of robust growth when exposed to phosphate levels comparable with that typically found in poultry litter. Data suggest intracellular phosphate levels in these strains increase in response to increasing phosphate in the medium or austere medium conditions. Intracellular phosphate did not reach levels comparable with known hyper-accumulating micro-organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: These data suggest poultry litter possesses a resident microflora that thrives and accumulates intracellular phosphate in response to high phosphate conditions.     

Genotyping of Campylobacter spp. from retail meats by pulsed-field gel electrophoresis and ribotyping

AIMS: To determine the genetic relatedness of Campylobacter spp. from retail meat products, and compare the discriminatory power of pulsed-field gel electrophoresis (PFGE) and automatic ribotyping. METHODS AND RESULTS: A total of 378 Campylobacter isolates recovered from 159 raw meats (130 chicken, 25 turkey, three pork and one beef) sampled from 50 retail grocery stores of four supermarket chains in the Maryland suburban area from August 1999 to July 2000 were analysed by PFGE with SmaI, 120 isolates of which were also characterized by ribotyping with PstI using RiboPrinter system. A total of 148 unique PFGE patterns were identified, 91 of which were present in multiple Campylobacter isolates and 24 in multiple meat samples. Nineteen Campylobacter clones with identical PFGE patterns recurred frequently (up to nine times) throughout the sampling period. Comparing ribotyping with PFGE, we identified 44 PFGE patterns and 22 RiboGroups among the 120 isolates tested. Multiple PFGE patterns within one RiboGroup were commonly observed, as well as multiple RiboGroups within one PFGE pattern. CONCLUSIONS: Although Campylobacter present in retail meats were genetically diverse, certain clones persisted in poultry meats. PFGE had a greater discriminatory power than ribotyping, and the two methods were complementary in genotyping Campylobacter. SIGNIFICANCE AND IMPACT OF THE STUDY: Genomic DNA fingerprinting of Campylobacter confirmed diverse and recurrent Campylobacter clones in the retail meats, which provides additional data for a better understanding of the epidemiological aspect of Campylobacter infection.     

Radiological toxicity of some fish and meat tissues consumed in southwestern Nigeria

The activity concentrations of natural radionuclides in 30 fish tissues and 30 meat organs have been determined using high purity germanium (HPGe) detector. For the fish tissues, the mean activity concentrations of ²³⁸U and ²³²Th were highest in Catfish (Clarias gariepinus) with values of 5.31 ± 1.30 and 6.09 ± 0.91 Bq/kg, respectively. The lowest mean activity concentrations of ²³⁸U and ²³²Th were seen in Titus (Scomberomorus tritor) and Croaker (Micropogonias undulatus), Croaker with values of 1.51 ± 2.08 and 64.42 ± 6.33 Bq/kg, respectively. The mean activity concentration of ⁴⁰K was highest in Micropogonias undulatus and lowest in Tilapia (Oreohronis niloticus) with values of 64.42 ± 6.33 and 6.53 ± 0.98 Bq/kg. For the meat organs, the highest mean activity concentration of ²³⁸U, ²³²Th, and ⁴⁰K was highest in kidney, liver, and heart, respectively with values of 2.82 ± 0.47, 4.57 ± 0.69, and 52.07 ± 7.81 Bq/kg. Small intestine had the lowest mean activity concentrations of ²³⁸U and ²³²Th with values of 1.14 ± 0.16 and 0.89 ± 0.08 Bq/kg, respectively. Beef had the lowest mean activity concentration of ⁴⁰K with a value of 17.61 ± 2.14 Bq/kg.     

Genotyping of thermotolerant Campylobacter from poultry slaughterhouse by amplified fragment length polymorphism

AIM: To examine the occurrence, diversity and transmission of Campylobacter in a poultry slaughterhouse. METHODS AND RESULTS: During a 4-week period, a slaughterhouse was sampled alternately during slaughtering and the following mornings post-disinfection. Samples were taken from poultry at six stages in the slaughter process and from 25 environmental sites. For positive broiler flocks slaughtered on one occasion, 92% and 48% of the environmental sites were positive during slaughter and post-disinfection, respectively. For positive laying hen flocks slaughtered on three occasions, 8-56% and 12-20% of the environmental sites were positive during slaughter and post-disinfection, respectively. Genetic fingerprinting by amplified fragment length polymorphism (AFLP) of the 109 isolates obtained resulted in 28 different AFLP clones. Five AFLP clones were present for more than 1 week. CONCLUSIONS: Slaughtering of Campylobacter-positive broilers resulted in extensive contamination of the slaughterhouse, including the air. A high proportion of the laying hen flocks were Campylobacter positive, but these caused less environmental contamination than the broilers. This, together with the freezing of all layer carcasses, results in a lower public health risk from laying hens, when compared with broilers. Significance and Impact of the Study: When slaughtering Campylobacter-positive broilers, the implementation of preventive measures is important to reduce contamination of negative carcasses and to protect the workers against infection.     

Enumeration of thermotolerant Campylobacter spp. from poultry carcasses at the end of the slaughter-line

AIM: To enumerate Campylobacter on poultry carcasses at the end of the slaughter-line, and investigate the extent to which Campylobacter from a positive flock were transmitted to other flocks during slaughter. METHODS AND RESULTS: The presence (in caeca) and the level (from carcasses) of Campylobacter were determined. The isolates were fingerprinted by amplified fragment length polymorphism (AFLP). A total of three of 13 broiler flocks and three of four-layer flocks harboured caecal Campylobacter. Carcasses from the caeca-positive broiler flocks were Campylobacter positive with numbers ranging from 2.6 x 10(4) to 2.6 x 10(6) CFU per carcass. Two caeca-negative broiler flocks, slaughtered directly after the positive broiler flocks, had the first carcasses contaminated with Campylobacter, with numbers below 2 x 10(4) CFU per carcass of the same AFLP haplotypes as the preceding flock. Campylobacter was detected on carcasses from only one of the caeca-positive layer flocks in numbers below 2 x 10(4) CFU per carcass. No Campylobacter was detected on carcasses from a flock succeeding the positive-layer flocks. CONCLUSION: Carcasses from Campylobacter-positive broiler flocks were heavily contaminated with Campylobacter, and transmitted low levels of Campylobacter to carcasses from negative flocks, slaughtered directly after. Campylobacter-positive layer flocks had low numbers of Campylobacter on the carcasses. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicate limited cross-contamination of Campylobacter between flocks at the slaughterhouse, reducing the advantage of logistic slaughter.     

Multiple-antibiotic resistance of Enterococcus spp. isolated from commercial poultry production environments

The potential impact of food animals in the production environment on the bacterial population as a result of antimicrobial drug use for growth enhancement continues to be a cause for concern. Enterococci from 82 farms within a poultry production region on the eastern seaboard were isolated to establish a baseline of susceptibility profiles for a number of antimicrobials used in production as well as clinical environments. Of the 541 isolates recovered, Enterococcus faecalis (53%) and E. faecium (31%) were the predominant species, while multiresistant antimicrobial phenotypes were observed among all species. The prevalence of resistance among isolates of E. faecalis was comparatively higher among lincosamide, macrolide, and tetracycline antimicrobials, while isolates of E. faecium were observed to be more frequently resistant to fluoroquinolones and penicillins. Notably, 63% of the E. faecium isolates were resistant to the streptogramin quinupristin-dalfopristin, while high-level gentamicin resistance was observed only among the E. faecalis population, of which 7% of the isolates were resistant. The primary observations are that enterococci can be frequently isolated from the poultry production environment and can be multiresistant to antimicrobials used in human medicine. The high frequency with which resistant enterococci are isolated from this environment suggests that these organisms might be useful as sentinels to monitor the development of resistance resulting from the usage of antimicrobial agents in animal production.