Campylobacter spp. is a significant and prevalent public health hazard globally. Campylobacter jejuni is the most frequently recovered species from human cases and poultry are considered the most ...important reservoir for its transmission to humans. In this study, 30 Campylobacter jejuni isolates were selected from clinical (n = 15) and broiler (n = 15) sources from a larger cohort, based on source, virulence, and antimicrobial resistance profiles. The objective of this study was to further characterise the genomes of these isolates including MLST types, population structure, pan-genome, as well as virulence and antimicrobial resistance determinants. A total of 18 sequence types and 12 clonal complexes were identified. The most common clonal complex was ST-45, which was found in both clinical and broiler samples. We characterised the biological functions that were associated with the core and accessory genomes of the isolates in this study. No significant difference in the prevalence of virulence or antimicrobial resistance determinants was observed between clinical and broiler isolates, although genes associated with severe illness such as neuABC, wlaN and cstIII were only detected in clinical isolates. The ubiquity of virulence factors associated with motility, invasion and cytolethal distending toxin (CDT) synthesis in both clinical and broiler C. jejuni genomes and genetic similarities between groups of broiler and clinical C. jejuni reaffirm that C. jejuni from poultry remains a significant threat to public health.
Light-emitting diode (LED) technologies are economical and efficient devices that could be considered in poultry processing as disinfection strategies. This study evaluated the efficacy of a ...LED-based device to reduce the microbial load on chicken meat and investigated it's impact on selected quality parameters. Quality parameters including pH, texture and color after LED-UV exposure and during subsequent storage for 7 days at 4 ̊C were investigated. Diced chicken breast fillets were exposed to UV light wavelengths of 255, 280, 300 and 365 nm for 2, 4, 6, 8 and 10 min. A microbiological analysis was conducted on chicken samples to enumerate bacterial counts. Reductions between 1.17 and 1.67 log CFU/g for total viable counts of mesophilic, psychrophilic bacteria and total Enterobacteriaceae counts were observed, whereas, up to 2 log CFU/g was obtained for Pseudomonas and lactic acid bacteria groups after treatment with wavelengths of 280, 300 and 365 nm. Furthermore, color, texture and pH were not affected by exposure to UV light at 280 nm even following 7 days storage. Thus, LED-based technologies could be applied on poultry meat to reduce the levels of spoilage bacteria while maintaining quality attributes.
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•Wavelengths of 280, 300 and 365 nm obtained the best inactivation results.•The most affected bacteria were the Pseudomonas genus and lactic acid bacteria.•Application of UV light at 280 min and storage did not alter pH, color and texture.•LED-UV based technology is a potential disinfection strategy of chicken fillets.
The transfer of blown pack spoilage causing Clostridium spores from the farm to the meat plant is of growing concern to the meat industry. This study investigated the environmental niches of these ...Clostridium spp., specifically Clostridium estertheticum and Clostridium gasigenes in the beef and sheep farm environments in New Zealand. Faecal, soil, grass, drinking water, puddle water and feed (fodder beet, hay, bailage and silage, where available) samples were collected on five beef and sheep farms during Winter and Spring in 2018, in North and South Island, respectively. Beef and sheep farm samples were tested for C. estertheticum and C. gasigenes using enrichment plus PCR, qPCR and direct plating. C. estertheticum was detected in bovine faecal (4%), soil (2–18%) and grass (0–12%) samples at concentration of up to 2.0 log10 cfu/g. C. gasigenes were found in 18–46% of faecal, 16–82% of soil, 12–44% of grass, 0–44.4% of drinking water and 0–58.3% of puddle water samples tested and the direct counts ranged from 2.4 log10 cfu/ml in puddle water to 3.4 log10 cfu/g in soil. C. estertheticum were detected by qPCR in sheep farms in ovine feces (2.3%), soil (2.3%) and fodder beet (10%). All other sample types (grass, drinking water, puddle water, baleage, hay, silage and fodder beet) were negative using direct and enrichment plus PCR methods. In contrast C. gasigenes was detected in of faecal (22.7–38.6%), soil (22.7–84.1%), grass (17.5–34.1%) drinking water (35.7–78.6%), puddle water (33.3–40%), hay baleage (57%), silage (2%) and fodder beet (10%) at concentrations of up to 3.7 log10 cfu/g/ml. It was concluded that C. estertheticum and C. gasigenes were common on beef and sheep farms with the latter having higher incidence and mean concentration.
•Higher prevalence of C. gasigenes than C. estertheticum on bovine and ovine farms.•Culture-dependent and independent methods to test for blown pack spoilage spores.•Blown pack spoilage Clostridium detected in grass and feed.•Blown pack spoilage Clostridium detected in drinking and puddle water.
The primary objective of this study was to characterise (microbiology and physical parameters) beef carcasses and primals during chilled storage. A minor aim was to compare observed growth of key ...spoilage bacteria on carcasses with that predicted by ComBase and the Food Safety Spoilage Predictor (FSSP). Total viable count (TVC), total Enterobacteriacae count (TEC), Pseudomonas spp., lactic acid bacteria (LAB), Brochothrix thermosphacta and Clostridium spp. were monitored on beef carcasses (n = 30) and primals (n = 105) during chilled storage using EC Decision 2001/471/EC and ISO sampling/laboratory procedures. The surface and/or core temperature, pH and water activity (aw) were also recorded. Clostridium (1.89 log10 cfu/cm2) and Pseudomonas spp. (2.12 log10 cfu/cm2) were initially the most prevalent bacteria on carcasses and primals, respectively. The shortest mean generation time (G) was observed on carcasses with Br. thermosphacta (20.3 h) and on primals with LAB (G = 68.8 h) and Clostridium spp. (G = 67 h). Over the course of the experiment the surface temperature decreased from 37 °C to 0 °C, pH from 7.07 to 5.65 and aw from 0.97 to 0.93 The observed Pseudomonas spp. and Br. thermosphacta growth was more or less within the range of predictions of Combase. In contrast, the FSSP completely overestimated the growth of LAB. This study contributes to the very limited microbiological data on beef carcasses and primals during chilling.
•Pseudomonas concentrations on beef primals at packaging increased during 6 weeks vacuum packaged storage.•Brochothrix thermosphacta grew faster than lactic acid bacteria on vacuum packaged beef primals.•Combase may be used to predict Pseudomonas spp. and Br. thermosphacta growth on beef carcasses.
Background:
Campylobacter
is commonly transmitted to humans from chickens.
Campylobacter jejuni
is the species most frequently associated with human illness, and the most prevalent species recovered ...from poultry.
Objective:
The objective of this study was to analyse a sub-population of
C. jejuni
from two broiler flocks on the farm and at slaughter using whole-genome sequencing to gain insights into the changes in the
Campylobacter
population during broiler production, including changes in virulence and antimicrobial resistance profiles.
Methods:
In this study, ten composite faecal samples (
n
=10), obtained by pooling ten fresh faecal samples (
n
=10), were collected in the broiler house on two farms on days 14, 21, 28, and 34 (
n
=80) and ten composite (
n
=10) caecal samples were collected at the time of slaughter for each flock (
n
=20). These were tested for
C. jejuni
using the ISO 10272-2:2016 method. Seven isolates were randomly selected from each of the nine
Campylobacter
-positive sampling points (
n
=63) and were subjected to antimicrobial susceptibility tests. Their genomes were sequenced and the data obtained was used to characterise the population structure, virulence, antimicrobial resistance determinants and inter-strain variation.
Results:
The Farm 1 isolates had three MLST types (ST257-257, ST814-661 and ST48-48) while those on Farm 2 were ST6209-464 and ST9401. Interestingly, only the MLST types positive for most of the virulence genes tested in this study persisted throughout the production cycle, and the detection of antimicrobial resistance determinants (
gyrA
T86I and
tetO
) increased after thinning and at slaughter, with the detection of new strains.
Conclusion:
The persistence of the most virulent strains detected in this study throughout the production cycle has important implications for the risk to consumers and requires further investigation. The detection of new strains within the population corresponding with the time of thinning and transportation reflects previous reports and provides further evidence that these activities pose a risk of introducing new
Campylobacter
strains to broiler batches.
Despite an increased incidence of Clostridioides difficile infections, data on the reservoirs and dissemination routes of this bacterium are limited. This study examined the prevalence and ...characteristics of C. difficile isolates in spinach fields. C. difficile was detected in 2/60 (3.3%) of spinach and 6/60 (10%) of soil samples using culture-based techniques. Whole genome sequencing (WGS) analysis identified the spinach isolates as belonging to the hypervirulent clade 5, sequence type (ST) 11, ribotypes (RT) 078 and 126 and carried the genes encoding toxins A, B and CDT. The soil isolates belonged to clade 1 with different toxigenic ST/RT (ST19/RT614, ST12/RT003, ST46/RT087, ST16/RT050, ST49/RT014/0) strains and one non-toxigenic ST79/RT511 strain. Antimicrobial resistance to erythromycin (one spinach isolate), rifampicin (two soil isolates), clindamycin (one soil isolate), both moxifloxacin and rifampicin (one soil isolate), and multi-drug resistance to erythromycin, vancomycin and rifampicin (two soil isolates) were observed using the E test, although a broader range of resistance genes were detected using WGS. Although the sample size was limited, our results demonstrate the presence of C. difficile in horticulture and provide further evidence that there are multiple sources and dissemination routes for these bacteria.
A blend of apple and cranberry juice was processed by a combination of a light-based technology (ultraviolet light (UV) (5.3
J/cm
2) or high intensity light pulses (HILP) (3.3
J/cm
2) in combination ...with pulsed electric fields (PEF) (34
kV/cm, 18
Hz, 93
μs) or manothermosonication (MTS) (5
bar, 43
°C, 750
W, 20
kHz). Selected physical and chemical attributes were evaluated pre- and post-processing, and the sensory attributes of non-thermally treated samples were compared to conventional pasteurisation (26
s, 72
°C). No significant changes were found in non-enzymatic browning, total phenolics and antioxidant activity of the juices. UV
+
PEF and HILP
+
PEF treatments did not affect the colour of the product and HILP
+
PEF processing retained more monomeric anthocyanins than any other combined treatment. Sensory analysis showed that UV
+
PEF and HILP
+
PEF combinations did not impact on odour and flavour of the juice, while combinations that included MTS adversely affected those attributes.
16S rRNA amplicon sequencing was used to investigate changes in the broiler gastrointestinal tract (GIT) microbiota throughout the rearing period and in combination with antibiotic treatment. Thirty ...birds (from a commercial flock) were removed at multiple points throughout the rearing period on days 13, 27, and 33, euthanised, and their GIT aseptically removed and divided into upper (the crop, proventriculus, and the gizzard), middle (the duodenum, jejunum, and ileum) and lower (the large intestine, the caeca, and the cloaca) sections. In a separate commercial flock, on the same farm with similar husbandry practices and feed, doxycycline (100 mg/ml per kg body weight) was administered in drinking water between day 8 and 12 (inclusive) of the production cycle. Birds were removed on days, 13, 27, and 33 and GIT samples prepared as above. The contents of three merged samples from each GIT section were pooled (
n
= 60), the DNA extracted and analysed by 16S rRNA amplicon metagenomic sequencing and analysed. Major changes in the broiler microbiota were observed as the birds aged particularly with the Firmicutes/Bacteroidetes ratio (F:B) of the lower GIT. Moreover, Chao1, ACE, and Shannon indices showed the antibiotic treatment significantly altered the microbiota, and this change persisted throughout the rearing period. Further research is required to investigate the effect of these changes on bird performance, susceptibility to infections and
Campylobacter
carriage.
Campylobacter jejuni remains a high priority in public health worldwide. Ultraviolet light emitting-diode technology (UV-LED) is currently being explored to reduce Campylobacter levels in foods. ...However, challenges such as differences in species and strain susceptibilities, effects of repeated UV-treatments on the bacterial genome and the potential to promote antimicrobial cross-protection or induce biofilm formation have arisen. We investigated the susceptibility of eight C. jejuni clinical and farm isolates to UV-LED exposure. UV light at 280 nm induced different inactivation kinetics among strains, of which three showed reductions greater than 1.62 log CFU/mL, while one strain was particularly resistant to UV light with a maximum reduction of 0.39 log CFU/mL. However, inactivation was reduced by 0.46-1.03 log CFU/mL in these three strains and increased to 1.20 log CFU/mL in the resistant isolate after two repeated-UV cycles. Genomic changes related to UV light exposure were analysed using WGS. C. jejuni strains with altered phenotypic responses following UV exposure were also found to have changes in biofilm formation and susceptibility to ethanol and surface cleaners.
The aim of this study was to examine the microbiota in broilers reared with and without antibiotics and to investigate differences between the upper, middle and lower sections of the gastrointestinal ...tract (GIT). One of two commercial flocks was treated with an antibiotic (T) (20 mg trimethoprim and 100 mg sulfamethoxazole per ml in the drinking water for 3 days) and the other was left untreated (UT). The GIT contents of 51 treated and untreated birds were aseptically removed from the upper (U), middle (M) and lower (L) sections. These were pooled in triplicate (n = 17 per section per flock), the DNA extracted and purified, 16S amplicon metagenomic sequencing performed and the resultant data analysed using a range of bioinformatics software. There were significant differences in the microbiota of the upper, middle and lower GIT, and treatment with the antibiotic significantly affected the microbiota in each of these sections. This study provides new data on broiler GIT microbiota and suggests that GIT location is a more important determinant of the constituent bacterial flora rather than the use or otherwise of antimicrobial treatments, at least when applied early in the production cycle.
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