Diversity of culturable psychrophilic and psychrotrophic anaerobic bacteria isolated from beef abattoirs and their environments

This study identified 431 psychrophilic or psychrotrophic isolates from commercial Irish beef abattoir environments and "blown packs" of vacuum-packed beef, using PCR and 16S rRNA sequencing, and estimated their intraspecies genetic diversity using restriction fragment length polymorphism (RFLP) analysis and spacer region PCR (SR-PCR). Twenty-five species were identified in the 431 isolates, with the most frequently recovered species being Clostridium gasigenes (n=315), Clostridium estertheticum (n=17), and a potentially novel species designated strain TC1 (n=52). These species were previously found to be associated with a particular type of spoilage known as blown-pack spoilage (BPS), which occurs in chilled-stored (i.e., -1.5°C to 4°C) vacuum-packaged meat within 2 to 4 weeks and involves the production of large volumes of gas. Overall, the study demonstrates the considerable and not previously reported diversity of the anaerobic microflora in abattoirs and the presence of a wide range of organisms capable of causing BPS at chilled temperatures.     

PCR detection of psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled meats

AIMS: To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of clostridia which cause 'blown pack' spoilage of vacuum-packed meat. METHODS AND RESULTS: Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of 'blown pack' causing clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of 'blown pack' causing clostridia, food clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT. The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g(-1) for non-enriched, and 102 CFU g(-1) for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of 'blown pack' spoilage in two packs, and Cl. estertheticum as the causative agent in the third. CONCLUSIONS: The developed method can be used for rapid detection of 'blown pack' causing clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 clostridial cells per gram. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of clostridial 'blown pack' spoilage in commercial spoiled packs, or for detection of psychrophilic clostridia in epidemiological trace back of 'blown pack' spoilage incidents in meat processing plants.     

The abattoir source of culturable psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled venison

AIMS: To identify the abattoir source(s) of culturable psychrophilic clostridia causing 'blown pack' spoilage of vacuum-packed chilled meats. METHODS AND RESULTS: Psychrophilic and psychrotolerant clostridia were isolated from hides, faeces and tonsils of deer slaughter stock, and from a meat plant environment. The isolates were differentiated using restriction fragment length polymorphism analysis of the 16S rDNA gene (PCR-RFLP) and 16S-23S rDNA internal transcribed spacer (ITS) analysis. PCR-RFLP group I clostridia were found to have restriction patterns indistinguishable from the patterns of 'blown pack'-causing Clostridium gasigenes DB1A(T) and R26. Gas production in packs inoculated with vegetative cells of PCR-RFLP group I clostridia was first evident after 14 days at 2 degrees C. The prevalence of these clostridia was similar in hide and faecal samples from slaughter animals, but these micro-organisms were absent from tonsils and the meat plant environment. Banding patterns of PCR-RFLP group II clostridia showed some cross-similarity with patterns of the 'blown pack'-causing micro-organism Cl. estertheticum DSM 8809(T) and Cl. estertheticum-like meat strains. The majority of clostridia in PCR-RFLP group II were found in the faeces of slaughter animals. Isolates representing PCR-RFLP group II did not, however, produce gas in vacuum packs stored at 2 degrees C for 84 days. CONCLUSIONS: The data suggest that soil particles attached to hide or present in faeces are the most probable primary reservoir from which 'blown pack' clostridia are introduced onto carcasses. Therefore, dressing procedure hygiene remains paramount in order to control the spread of psychrophilic Clostridium spp. in a meat plant. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper provides information critical for controlling 'blown pack' spoilage in meat processing plants. It reports on the use of molecular techniques for determination of abattoir sources of 'blown pack'-causing clostridia.     

Quantitative isolation efficiency of O26, O103, O111, O145 and O157 STEC serotypes from artificially contaminated food and cattle faeces samples using a new isolation protocol

Aims:  A range of new differential and confirmation plating media for some non-O157 Shiga toxin producing Escherichia coli (STEC) serotypes (O26, O103, O111, O145) and both sorbitol-positive and -negative O157 were evaluated using artificially contaminated samples.
Methods and Results:  Dairy products (raw milk, cheese made from pasteurized milk and raw milk), meat (ground beef, fermented meat) and cattle faeces were artificially contaminated using clinical STEC strains. Isolation efficiency was 100%, 82·3%, 88·5%, 65·9%, 64·3% and 15·8%, respectively, for an inoculum size of ≤100 CFU 25 g⁻¹. The consecutive use of differential and confirmation media limited the incidence of false positive isolates from 0% for raw milk samples, cheese made from pasteurized milk and for fermented meat to 2·1% for cheese made from raw milk, and to 8·9% for ground beef.
Conclusions:  Data presented in this paper indicated that the efficiency of the applied isolation method was dependent on sample-to-sample variation but not on the inoculum size.
Significance and Impact of Study:  Data in this paper indicated that isolation of low levels of non-O157 and sorbitol-positive O157 STEC from food samples is possible.     

Development of real-time PCR tests for detecting botulinum neurotoxins A, B, E, F producing Clostridium botulinum, Clostridium baratii and Clostridium butyricum

Aims:  To develop real-time PCR assays for tracking and tracing clostridia responsible for human botulism.
Methods and Results:  Real-time PCR assays based on the detection of the genes ntnh encoding the nontoxin-nonhaemagglutinin (NTNH) proteins or the most homologous regions of the botulinum neurotoxin ( bont ) genes have been developed together with four real-time PCR assays, each being specific of the genes bont/A , bont/B , bont/E , bont/F and enables a toxin type-specific identification. The specificity of the assays was demonstrated using a panel of botulinum toxin producing clostridia (29 strains), nonbotulinum toxin producing clostridia (21 strains) and various other bacterial strains. The toxin type-specific assays had a sensitivity of 100 fg–1000 fg of total DNA in the PCR tube (25–250 genome equivalents) which correspond to 10³ to 10⁴ cells ml⁻¹. After a 48 h enrichment in anaerobic conditions, these PCR assays allowed the detection of Clostridium botulinum type A in a naturally contaminated sample of 'foie gras' suspected in a C. botulinum outbreak.
Conclusion:  These PCR tests are specific and reliable for detection of heterogeneous BoNT producing clostridia responsible for human botulism.
Significance and Impact of the Study:  Adoption of these PCR assays is a step forward a reliable and rapid detection of these clostridia in food samples.     

The potential use of chilling to control the growth of Enterobacteriaceae on porcine carcasses and the incidence of E. coli O157:H7 in pigs

Aims:  To (i) monitor the presence of Enterobacteriaceae as indicators of faecal contamination on pig carcasses, (ii) examine the potential use of chilling as a critical control point (CCP) and establish its influence on pig carcass categorization by Decision 471/EC and (iii) determine the incidence of E. coli O157:H7 in pigs.
Methods and Results:  Porcine faecal samples and carcass swabs were collected before and after chilling at four Irish pig abattoirs and examined for Enterobacteriaceae and E. coli O157:H7. Chilling generally reduced Enterobacteriaceae counts on carcasses, but increases were also observed, particularly in one abattoir. E. coli O157:H7 was absent from carcasses before chilling, present on 0·21% after chilling and was recovered from 0·63% of faecal samples. All of the isolates were found to contain virulence genes associated with clinical illness in humans.
Conclusions:  The data show that overall chilling had the capacity to reduce the numbers of carcasses positive for the presence of Enterobacteriaceae .
Significance and Impact of Study:  The influence of chilling on the categorization of pig carcasses suggests that it has the potential to improve the numbers of acceptable carcasses and the process could be used as a CCP within a HACCP plan.     

Molecular typing and identification of Bdellovibrio-and-like organisms isolated from seawater shrimp ponds and adjacent coastal waters

Aims:  To apply and compare two PCR-based methods for typing saltwater Bdellovibrio- and-like organisms (BALOs) and to understand ecological and phylogenetic aspects of the BALOs isolated from shrimp mariculture systems.
Methods and Results:  Using double-layer agar technique, the numbers of culturable BALOs that lyse Vibrio alginolyticus were found to be 10–10³ PFU ml⁻¹ in the surface water samples. A total of 130 BALOs isolates were differentiated into five phylotypes by denaturing gradient gel electrophoresis targeting the 16S rDNA V3 region and four phylotypes by amplified rDNA restriction analysis of the Bacteriovoracaceae -specific 16S rDNA fragment respectively. Phylogenetic analysis of representative isolates showed that all of them were identified as Bacteriovorax spp., but affiliated with four different clusters in the family Bacteriovoracaceae.
Conclusions:  The two PCR-based methods both can be chosen to rapidly type the saltwater BALOs at cluster level. And the relatively large numbers of BALOs with various phylotypes recovered from the same habitats suggested that these predators might play important ecological role in shrimp mariculture environments.
Significance and Impact of the Study:  We proposed two effective methods to distinguish rapidly large numbers of BALOs isolates and our results would be helpful to understand the diversity and function of BALOs in mariculture environments.     

PCR detection of psychrotolerant clostridia associated with deep tissue spoilage of vacuum-packed chilled meats

AIMS: To develop a practical molecular procedure that directly (without isolation) and specifically detects the presence of clostridia, which cause the deep tissue spoilage condition. METHODS AND RESULTS: A primer set was designed and a PCR amplification procedure developed to detect the presence of Clostridium algidicarnis and Cl. putrefaciens 16S rDNA gene fragments in meat. The procedure yielded amplicons of the expected size with homologous DNA templates, but failed to give PCR products with DNAs from 47 food clostridia and common meat spoilage micro-organisms. The minimum level of detection was 10(4) cfu g-1 for nonenriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, the presence of Cl. algidicarnis and/or Cl. putrefaciens was confirmed in a swab sample taken from the cartilage of an ovine stifle joint, which on opening exhibited strong offensive odours. CONCLUSIONS: The developed method can be used for rapid detection of clostridia causing deep tissue spoilage in commercial vacuum packs. SIGNIFICANCE AND IMPACT OF THE STUDY: The paper reports practical procedures that can be used for rapid confirmation of the causative agents of deep tissue clostridial spoilage in commercial vacuum-packed chilled meats.     

Detection of the tdh and trh genes in Vibrio parahaemolyticus isolates in fish and mussels from Middle Black Sea Coast of Turkey

Aim:  The aim of this study was to demonstrate the occurrence of potential pathogenic Vibrio parahaemolyticus in seafoods using DNA-based techniques in comparison with bacteriological methods.
Methods and Results:  From 120 fresh and processed fish and mussel samples collected from Middle Black Sea, 32 isolates were identified as V. parahaemolyticus by bacteriological methods and confirmed by tl gene-based conventional PCR. Of them, 13 isolates were found positive for only tdh gene, six isolates for only trh gene and 13 isolates for both genes by multiplex PCR.
Conclusions:  It is the first report demonstrating the presence of potential pathogenic V. parahaemolyticus isolates from the Black Sea seafoods by PCR detection of tl , trh and tdh genes that was found more rapid than bacteriological methods.
Significance and Impact of the Study:  This study confirmed the previous reports that characterization of potential pathogenic V. parahaemolyticus isolates based on the PCR techniques was reliable and cost-effective. These results suggest that molecular detection methods should be included in Turkish Standards of seafood control in addition to bacteriological methods.     

Development of a real-time PCR assay with an internal amplification control for the screening of Shiga toxin-producing Escherichia coli in foods

Aims:  To develop and evaluate a real-time PCR assay incorporating an internal amplification control (IAC) suitable for the screening of Shiga toxin (Stx)-producing Escherichia coli (STEC) in foods.
Methods and Results:  A competitive IAC was constructed and included in an stx -specific real-time PCR assay. Coupled to 18-h enrichment and automated DNA extraction, the assay could reliably detect the presence of STEC in minced meats inoculated at 10 CFU per 25 g. Its performance was evaluated on 415 minced beef and 112 raw milk cheese samples and compared with that of a PCR-ELISA method. Fifty-three minced meats and 31 cheeses were found stx -positive, giving 98·3% and 93·75% concordance, respectively, with the PCR-ELISA reference method.
Conclusions:  A highly sensitive stx -specific real-time PCR method including an IAC was developed, facilitating monitoring of false-negative results due to PCR inhibitors.
Significance and Impact of the Study:  Combined with automated DNA extraction, the stx -IAC real-time PCR assay represents a suitable method for rapid screening of STEC in foods.     

Clostridia spore formation during aerobic deterioration of maize and sorghum silages as influenced by Lactobacillus buchneri and Lactobacillus plantarum inoculants

Aims:  The effect of the inoculation of maize and sorghum silages with Lactobacillus plantarum (LP) and Lactobacillus buchneri (LB) on the clostridia spore formation during aerobic deterioration has been studied.
Methods and results:  The crops were ensiled in 30 l jars, without a lactic acid bacteria inoculant (C), and with an LP or LB inocula (theoretical rate of 1 × 10⁶). After 90 days of conservation, the silages were analysed for the chemical and microbiological characteristics and subjected to an aerobic stability test, during which pH, temperature, nitrate, yeast, mould and clostridia spores were measured. Compared to the C and LP silages, yeasts were reduced in the LB silages, resulting in an increased aerobic stability. Clostridia spores, determined by most probable number (MPN) procedure, increased to 6 log₁₀ MPN g⁻¹ in the C and LP maize silages, whereas they reached 3 log₁₀ MPN g⁻¹ in C and LP sorghum silages.
Conclusions:  Clostridia spore count only slightly increased in the LB maize silages after 342 h (2·59 log₁₀ MPN g⁻¹), whereas it did not show any increase in the LB sorghum silages for the whole period of air exposure.
Significance and impact of the study:  The data indicated that clostridia spore outgrowth can take place during silo feedout in aerobic-deteriorated silages and that LB inoculation reduces the risk of clostridia outgrowth after silage opening by increasing the aerobic stability.     

Molecular typing of Clostridium perfringens isolated from turkey meat by multiplex PCR

Aims:  To determine the presence of toxin genes in 22 Clostridium perfringens isolated from turkey meat samples by molecular typing.
Methods and Results:  For this purpose, alpha ( cpa ), beta ( cpb ), beta 2 ( cpb2 ), epsilon ( etx ), iota ( iA ) and enterotoxin ( cpe ) toxin genes were analysed by multiplex PCR. All 22 turkey meat Cl. perfringens isolates were found to carry the cpa , gene but in none of the isolates cpb , etx, iap or cpe genes were detected. Results showed that all isolates represented type A and were cpe negative.
Conclusions:  Our results indicate that Cl. perfringens type A is the most common type in turkey meat. Also multiplex PCR is effective and rapid method for typing of Cl. perfringens .
Significance and Impact of the Study:  It is the first study about molecular typing of Cl. perfringens using multiplex PCR in turkey meat samples in Turkey.     

Characterization of Metarhizium species and varieties based on molecular analysis, heat tolerance and cold activity

Aims:  The genetic relationships and conidial tolerances to high and low temperatures were determined for isolates of several Metarhizium species and varieties.
Methods and Results:  Molecular-based techniques [AFLP and rDNA (ITS1, ITS2 and 5·8S) gene sequencing] were used to characterize morphologically identified Metarhizium spp. isolates from a wide range of sources. Conidial suspensions of isolates were exposed to wet heat (45 ± 0·2°C) and plated on potato dextrose agar plus yeast extract (PDAY) medium. After 8-h exposure, the isolates divided clearly into two groups: (i) all isolates of Metarhizium anisopliae var. anisopliae ( Ma-an ) and Metarhizium from the flavoviride complex ( Mf ) had virtually zero conidial relative germination (RG), (ii) Metarhizium anisopliae var. acridum ( Ma-ac ) isolates demonstrated high heat tolerance ( c . 70–100% RG). Conidial suspensions also were plated on PDAY and incubated at 5°C for 15 days, during which time RGs for Ma-an and Ma-ac isolates were virtually zero, whereas the two Mf were highly cold active (100% RG).
Conclusions:  Heat and cold exposures can be used as rapid tools to tentatively identify some important Metarhizium species and varieties.
Significance and Impact of the Study:  Identification of Metarhizium spp. currently relies primarily on DNA-based methods; we suggest a simple temperature-based screen to quickly obtain tentative identification of isolates as to species or species complexes.     

Arcobacter contamination on pre- and post-chilled bovine carcasses and in minced beef at retail

Aims:  The present study aimed to assess the Arcobacter contamination on bovine carcasses postevisceration and postcooling in two slaughterhouses and in ready-to-eat minced beef.
Methods and Results:  Carcasses ( n  = 247) were sampled at four sites in two slaughterhouses and 100 minced beef samples were collected at retail. Isolation was performed by a quantitative and qualitative Arcobacter selective method, and the isolates were identified by multiplex PCR, after which a part of them were characterized by enterobacterial repetitive intergenic consensus (ERIC)-PCR. Although arcobacters were isolated from 37% of the bovine carcasses postevisceration with the chest and the foreleg as most contaminated sites, cooling the carcasses for at least 24 h reduced the incidence of Arcobacter (7%) on the carcass surface significantly. Arcobacter butzleri was the species most frequently isolated, although co-contamination with multiple species also occurred. At retail, arcobacters were present in 9% of the minced beef samples, with Arcobacter butzleri as the dominant species.
Conclusions:  Forced air cooling of bovine carcasses for at least 24 h decreased the number of positive carcasses, but did not eliminate all arcobacters.
Significance and Impact of the study:  This study demonstrates that maintaining good hygiene practices throughout the food supply chain is crucial to ensure safe food products at the consumer level.     

Assessment of various methods for extraction of metagenomic DNA from saline habitats of coastal Gujarat (India) to explore molecular diversity

Aims:  To develop total DNA extraction protocol from saline soil for further metagenomic applications.
Methods and Results:  The protocols combine the application of mechanical (Beads and Sonicator) and Soft Lysis (SDS and enzymes) method for the isolation of total DNA from saline soil of coastal Gujarat followed by its quantification and purity assessment. The quality and purity of metagenomic DNA was quite consistent and reliable, although it contained residual concentartions of humic acid. The extracted DNA was used to successfully amplify 16S rRNA region. The amplicons were suitable for further applications such as diversity-based analysis by denaturing gradient gel electrophoresis (DGGE).
Conclusions:  The methods appear to have wide applicability in investigating molecular diversity and exploring functional genes from the total DNA.
Significance and Impact of the Study:  The protocol is simple, short and facilitates rapid isolation of PCR amplifiable total genomic DNA from saline soil. The method yielded good quality of the DNA suitable for metagenomic studies. The results are also significant as only few extreme environments, particularly saline habitats, are explored for their metagenomic potential.     

Development of a Selective Medium for the Isolation of Clostridium sporogenes and Related Organisms

An attempt was made to develop a selective isolation medium for Clostridium sporogenes and related organisms based on the ability of these organisms to obtain their energy for growth by means of coupled oxidation-reduction reactions between appropriate pairs of amino acids (Stickland reaction). Using a semi-defined basal medium containing various combinations of amino acids, it was found that Cl. sporogenes utilized a wider range of amino acid pairs than strains of five other species of clostridia known to carry out a Stickland-type fermentation.
With alanine and proline as the principal energy sources and the medium solidified with agar. it was shown that reference strains of Cl. sporogenes and proteolytic Cl. botulinum types A, B and F could be recovered almost quantitatively, with or without prior heating at 80 °C for 10 min. By contrast, growth of test strains of Streptococcus faecalis, Strep. faecium , 'saccharolytic' Cl. botulinum types B, C, D, E and F and 'proteolytic' strains of types C and D was suppressed on this medium, as were strains of 26 other species of clostridia.
Addition of 50 μg/ml of polymyxin to the agar medium had no detectable effect on the recovery of Cl. sporogenes or Cl. botulinum. When samples of soil and mud were plated on the antibiotic-containing medium, 63.1% of 225 isolates thus obtained were identified as Cl. sporogenes/botulinum.     

Effect of selected antimicrobial compounds on the radiosensitization of Salmonella Typhi in ground beef

Aims:  In this study, we extended our previous work to determine the efficiency of antimicrobial compounds in increase of relative radiosensitivity of Salmonella Typhi in medium fat ground beef (23% fat) by testing 41 different essential oils (EOs), oleoresins and food sauces.
Methods and Results:  Ground beef samples inoculated with Salmonella Typhi (10⁶ CFU g⁻¹ ) were treated with each antimicrobial compound at a concentration of 0·5% (w/w). Then, the samples (25 g each) were packaged under air and irradiated in a ⁶⁰Co irradiator at doses from 0 to 1·75 kGy. Radiosensitivity was evaluated by calculating relative radiation sensitivity, defined as the ratio of radiation D ₁₀ value in the absence/presence of antimicrobial compound.
Conclusions:  Depending on the compound tested, the addition of antimicrobial compound decreased the D ₁₀ value of Salmonella Typhi, resulting in an increase of the radiation sensitivity up to more than four times. Among these antimicrobial compounds, Chinese cinnamon EO, clove EO and trans -cinnamaldehyde were most effective to increase the radiosensitivity of Salmonella Typhi in ground beef.
Significance and Impact of the Study:  These observations demonstrate that some active compounds can function as radiosensitizers of Salmonella Typhi.     

Comparison of traditional and molecular analytical methods for detecting biological agents in raw and drinking water following ultrafiltration

Aims:  To compare the performance of traditional methods to quantitative polymerase chain reaction (qPCR) for detecting five biological agents in large-volume drinking-water samples concentrated by ultrafiltration (UF).
Methods and Results:  Drinking-water samples (100 l) were seeded with Bacillus anthracis , Cryptospordium parvum , Francisella tularensis , Salmonella Typhi , and Vibrio cholerae and concentrated by UF. Recoveries by traditional methods were variable between samples and between some replicates; recoveries were not determined by qPCR. Francisella tularensis and V. cholerae were detected in all 14 samples after UF, B. anthracis was detected in 13, and C. parvum was detected in 9 out of 14 samples. Numbers found by qPCR after UF were significantly or nearly related to those found by traditional methods for all organisms except for C. parvum . A qPCR assay for S. Typhi was not available.
Conclusions:  qPCR can be used to rapidly detect biological agents after UF as well as traditional methods, but additional work is needed to improve qPCR assays for several biological agents, determine recoveries by qPCR, and expand the study to other areas.
Significance and Impact of the Study:  To our knowledge, this is the first study to compare the use of traditional and qPCR methods to detect biological agents in large-volume drinking-water samples.     

Development of a novel artificial medium based on utilization of algal photosynthetic metabolites by symbiotic heterotrophs

Aims:  (i) Quantitative and qualitative analyses of photosynthetic metabolites of Chlorella sorokiniana and elucidation of the mechanism of their utilization by algal symbionts. (ii) Development of artificial medium that imitates photoautotroph–heterotroph interaction and investigation of its suitability for isolation of novel microbes from the environment.
Methods and Results:  Various components, including free dissolved carbohydrates, nitrogenous compounds and vitamin, were detected and together contributed 11·1% (as carbon content) of the total photosynthetic metabolites in the medium. Utilization of these photosynthetic metabolites in algal culture broth by algal symbionts was studied. Many symbionts showed specific utilization patterns. A novel artificial extracellular released organic carbon medium, which imitated the nutritional conditions surrounding algae, was developed based on the pattern of utilization of the algal metabolites by the symbiotic heterotrophs. About 42·9% of the isolates were closely related to photoautotrophic-dependent and oligotrophic bacteria.
Conclusions:  With the novel artificial medium, it was possible to selectively isolate some bacterial strains.
Significant and Impact of the Study:  Synthetic bacterial growth medium is an important and basic tool for bacterial isolation from environmental samples. The current study shows that preferential separation of typical bacterial subset can be achieved by using artificial medium that mimics photosynthetic metabolites.     

Prevalence of Campylobacter spp. in a subset of intensive poultry flocks in Ireland

Aim:  The aim of this study was to investigate the prevalence of Campylobacter species in a subset of intensive poultry flocks by examining samples collected in geographically disparate areas on the island of Ireland.
Methods and Results:  Faecal, water and environmental samples were collected from the interior of poultry houses on nine farms. Three cultural methods were used for Campylobacter isolation: direct plating, enrichment culture and a recovery method for emerging Campylobacter spp. Presumptive Campylobacter isolates were confirmed using biochemical tests and further identified to species level by multiplex PCR. All flocks sampled in this study were found to be contaminated with Campylobacter at the time of sampling. Structural and air samples taken from the interior of broiler houses were also found to be Campylobacter positive. All water samples were found to be Campylobacter negative. The Campycheck method was used for the isolation of emerging Campylobacter spp.
Conclusions:  Campylobacter spp. were recovered (as contaminants) from the poultry house interior, air and environmental samples in all intensive poultry flocks surveyed.
Significance and Impact of the Study:  This study highlights the need for improved biosecurity on selected poultry farms.