Yasser Sanad | NCTR/FDA (Nat'l. Center for Toxicological Research) (original) (raw)

Papers by Yasser Sanad

Research paper thumbnail of Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development

Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to in... more Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli.

Research paper thumbnail of Bacterial Populations Associated with Smokeless Tobacco Products

Research paper thumbnail of Molecular Characterization of Salmonella enterica Serovars Isolated from a Turkey Production Facility in the Absence of Selective Antimicrobial Pressure

Research paper thumbnail of Insights into potential pathogenesis mechanisms associated with Campylobacter jejuni-induced abortion in ewes

Research paper thumbnail of Phenotypic and Genotypic Diversity of Thermophilic Campylobacter spp. in Commercial Turkey Flocks: A Longitudinal Study

Poultry are recognized as a main reservoir of Campylobacter spp. However, longitudinal studies in... more Poultry are recognized as a main reservoir of Campylobacter spp. However, longitudinal studies investigating the persistence of Campylobacter on commercial meat turkeys are rare. The objectives of this study were to determine the prevalence, antimicrobial susceptibility, and persistence of genotypically related strains of Campylobacter spp. recovered from three commercial turkey farms in Ohio belonging to a single producer. Eight hundred ten samples were collected from birds aged 1 week to slaughter, consisting of 750 fecal droppings and 60 ceca at slaughter. Overall Campylobacter prevalence was 55.9%. Multiplex polymerase chain reaction (PCR) confirmed 72.3% of all isolates as C. coli, 5.3% as C. jejuni, 10.6% as both, and 11.9% as other Campylobacter spp. PCR restriction fragment length polymorphism of the flaA gene subtyping detected 70 types-62 for C. coli and 8 for C. jejuni isolates-with most (80%) of flaA-types constituting farm homogeneous groups. Multilocus sequence typing of 99 selected Campylobacter isolates resulted in 23 sequence types (STs), consisting of 8 STs for C. jejuni and 15 STs for C. coli isolates. Six novel STs-four for C. jejuni and two-for C. coli, were detected. In a subset of isolates (n = 98) tested for antimicrobial resistance, the most common resistance was to tetracycline (95%), followed by azithromycin (43%), while 42% and 18% of the isolates were resistant to ciprofloxacin and erythromycin, respectively. All isolates were susceptible to florfenicol. C. coli isolates displayed a higher proportion of resistance than C. jejuni to most antimicrobials. This study highlights the high prevalence, genotypic diversity, and antimicrobial resistance of Campylobacter spp. in commercial turkey from farm to slaughter.

Research paper thumbnail of The impairment of methylmenaquinol:fumarate reductase affects hydrogen peroxide susceptibility and accumulation in Campylobacter jejuni

The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respirator... more The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respiratory (redox) protein that contributes to the metabolism of fumarate and displays homology to succinate dehydrogenase (Sdh). Since chemically oxidized redox-enzymes, including fumarate reductase and Sdh, contribute to the generation of oxidative stress in Escherichia coli, we assessed the role of Mfr in C. jejuni after exposure to hydrogen peroxide (H 2 O 2 ). Our results show that a Mfr mutant (ΔmfrA) strain was less susceptible to H 2 O 2 as compared to the wildtype (WT). Furthermore, the H 2 O 2 concentration in the ΔmfrA cultures was significantly higher than that of WT after exposure to the oxidant. In the presence of H 2 O 2 , catalase (KatA) activity and katA expression were significantly lower in the ΔmfrA strain as compared to the WT. Exposure to H 2 O 2 resulted in a significant decrease in total intracellular iron in the ΔmfrA strain as compared to WT, while the addition of iron to the growth medium mitigated H 2 O 2 susceptibility and accumulation in the mutant. The ΔmfrA strain was significantly more persistent in RAW macrophages as compared to the WT. Scanning electron microscopy showed that infection with the ΔmfrA strain caused prolonged changes to the macrophages' morphology, mainly resulting in spherical-shaped cells replete with budding structures and craters. Collectively, our results suggest a role for Mfr in maintaining iron homeostasis in H 2 O 2 stressed C. jejuni, probably via affecting the concentrations of intracellular iron.

Research paper thumbnail of Respiratory proteins contribute differentially to Campylobacter jejuni's survival and in vitro interaction with hosts' intestinal cells

The genetic features that facilitate Campylobacter jejuni's adaptation to a wide range of environ... more The genetic features that facilitate Campylobacter jejuni's adaptation to a wide range of environments are not completely defined. However, whole genome expression studies showed that respiratory proteins (RPs) were differentially expressed under varying conditions and stresses, suggesting further unidentified roles for RPs in C. jejuni's adaptation. Therefore, our objectives were to characterize the contributions of selected RPs to C. jejuni's ikey survival phenotypes under different temperature (37°C vs. 42°C) and oxygen (microaerobic, ambient, and oxygen-limited/anaerobic) conditions and ii-its interactions with intestinal epithelial cells from disparate hosts (human vs. chickens).

Research paper thumbnail of An evaluation of the effect of sodium bisulfate as a feed additive on Salmonella enterica serotype Enteritidis in experimentally infected broilers

Research paper thumbnail of Evaluating the Occurrence of Host-Specifi c Bacteroidales, General Fecal Indicators, and Bacterial Pathogens in a Mixed-Use Watershed

Fecal contamination of water is very common, and, in the United States, prevention is complicated... more Fecal contamination of water is very common, and, in the United States, prevention is complicated by the colossal span of waterways (>3.5 million miles), heterogeneous sources of pollution, and competing interests in water monitoring. Th e focus of this study was the Upper Sugar Creek Watershed, a mixed-use watershed with many headwater streams and one of the most contaminated waterways in Ohio. Quantitative polymerase chain reaction (qPCR) and hostspecifi c PCR for Bacteroidales were evaluated for the potential to discern sources of fecal contamination. Pathogen-specifi c qPCR and culturable Escherichia coli by most probable number (MPN) were compared at 21 established water quality monitoring sites in the watershed headwaters. Lower numbers of ruminantspecifi c Bacteroidales markers were detected in the base fl ow water samples compared with the human-specifi c Bacteroidales marker, suggesting the presence of hotspots of human fecal contamination. Bacteroidales qPCR and E. coli MPN showed signifi cant correlation (R 2 = 0.57; P < 0.001). Correlation between general fecal indicator and pathogen concentrations was weak or nonexistent. Coexistence of Salmonella and human-specifi c Bacteroidales was common (P = 0.015). Bacteroidales qPCR may have a greater potential for predicting fecal contamination due to its sensitivity, rapid analysis, and availability of host-specifi c assays. However, the lack of a strong correlation between pathogens and general fecal indicators suggests that assessment of health risk associated with fecal contamination will require a complement of approaches.

Research paper thumbnail of Molecular Epidemiology and Public Health Relevance of Campylobacter Isolated from Dairy Cattle and European Starlings in Ohio, USA

Dairy cattle serve as a potential source for Campylobacter infection in humans. Outbreaks associa... more Dairy cattle serve as a potential source for Campylobacter infection in humans. Outbreaks associated with consumption of either Campylobacter contaminated raw milk or contaminated milk after treatment were previously recorded in the United States. Further, starlings have been implicated in the spread of bacterial pathogens among livestock. Here, we determined the prevalence, genotypic, and phenotypic properties of Campylobacter isolated from fecal samples of dairy cattle and starlings found on the same establishment in northeastern Ohio. Campylobacter were detected in 83 (36.6%) and 57 (50.4%) out of 227 dairy and 113 starling fecal samples, respectively. Specifically, 79 C. jejuni, five C. coli, and two other Campylobacter spp. were isolated from dairy feces, while all isolates from starlings (n = 57) were C. jejuni. Our results showed that the prevalence of C. jejuni in birds was significantly ( p < 0.01) higher than that in dairy cattle. The pulsed-field gel electrophoresis analysis showed that C. jejuni were genotypically diverse and host restricted; however, there were several shared genotypes between dairy cattle and starling isolates. Likewise, many shared clonal complexes (CC) between dairy cattle and starlings were observed by multilocus sequence typing (MLST) analysis. As in humans, both in cattle and starlings, the CC 45 and CC 21 were the most frequently represented CCs. As previously reported, CC 177 and CC 682 were restricted to the bird isolates, while CC 42 was restricted to dairy cattle isolates. Further, two new sequence types (STs) were detected in C. jejuni from dairy cattle. Interestingly, cattle and starling C. jejuni showed high resistance to multiple antimicrobials, including ciprofloxacin, erythromycin, and gentamicin. In conclusion, our results highlight starlings as potential reservoirs for C. jejuni, and they may play an important role in the epidemiology of clinically important C. jejuni in dairy population.

Research paper thumbnail of Upper Sugar Creek Watershed, Ohio: A Model Watershed for Study of Pathogen Origin, Fate and Transport

Research paper thumbnail of Occurrence of the invasion associated marker (iam) in Campylobacter jejuni isolated from cattle

Research paper thumbnail of Genotypic and Phenotypic Properties of Cattle-Associated Campylobacter and Their Implications to Public Health in the USA

Since cattle are a major source of food and the cattle industry engages people from farms to proc... more Since cattle are a major source of food and the cattle industry engages people from farms to processing plants and meat markets, it is conceivable that beef-products contaminated with Campylobacter spp. would pose a significant public health concern. To better understand the epidemiology of cattle-associated Campylobacter spp. in the USA, we characterized the prevalence, genotypic and phenotypic properties of these pathogens. Campylobacter were detected in 181 (19.2%

Research paper thumbnail of Polyphosphate Kinase 2: A Novel Determinant of Stress Responses and Pathogenesis In Campylobacter Jejuni

Research paper thumbnail of Use of Bioluminescence Imaging to Monitor Campylobacter Survival In Chicken Litter

Journal of Applied …

Aim: The aim of this study was to develop a novel approach for characterizing the growth and per... more Aim: The aim of this study was to develop a novel approach for characterizing the growth and persistence of Campylobacter in different poultry-rearing environments. Specifically, we constructed bioluminescent Campylobacter strains and used them to monitor the survival of these pathogens in litter (bedding) material.Methods and Results: We inserted shuttle plasmids carrying the luminescence genes (luxCDABE) into C. jejuni and C. coli to construct bioluminescent strains of these pathogens. The strains were spiked into microcosms containing samples of litter-washings and dry litter collected from different enclosures that housed broiler chickens. Our results show that C. jejuni and C. coli survived for at least 20 days in reused (old) litter while the growth of these pathogens was inhibited in clean (new) litter. Furthermore, our results suggest that the availability of nutrients and the condition of the litter (reused vs new) are important factors in the persistence of these pathogens.Conclusions: Reused litter can potentially predispose chickens to Campylobacter contamination and maintaining clean litter might reduce the incidences of colonization with these pathogens.Significance and Impact of the Study: Bioluminescence provided a simple, sensitive, and rapid approach for analysing the growth dynamics of Campylobacter. Using this technology, we highlighted the potential role of litter material in maintaining these pathogens in the chicken environment.

Research paper thumbnail of Evaluation of Incompatibility Group I1 (IncI1) Plasmid-Containing Salmonella enterica and Assessment of the Plasmids in Bacteriocin Production and Biofilm Development

Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to in... more Mobile genetic elements, such as plasmids, can potentially increase the ability of bacteria to infect and persist in vertebrate host cells. IncI1 plasmids are widely distributed in Salmonella from food animal sources and associated with clinically important strains. These plasmids often encode antimicrobial resistance; however, little is known about their impact on the virulence of Salmonella strains. To assess the potential impact of the plasmids on virulence, 43 IncI1-positive Salmonella isolates from human and animal sources were subjected to whole genome sequence (WGS) analyses and evaluated for their abilities to invade and persist for 48 h in Caco-2 human intestinal epithelial cells, form biofilms and encode bacteriocins. Draft WGS data were submitted to predict the presence of virulence and antimicrobial resistance genes, plasmid replicon types present, conduct plasmid multilocus sequence typing (pMLST), and core genome MLST (cgMLST) in the isolates. Caco-2 cells were infected with Salmonella strains and incubated for both one and 48 h for the invasion and persistence assays, respectively. Additionally, Salmonella isolates and IncI1 plasmid carrying transconjugants (n = 12) generated in Escherichia coli were assessed for their ability to produce biofilms and bacteriocin inhibition of growth of other bacteria. All Salmonella isolates infected Caco-2 cells and persisted in the cells at 48 hrs. Persistent cell counts were observed to be significantly higher than invasion assay cell counts in 26% of the isolates. Among the IncI1 plasmids, there were 18 pMLST types. Nearly 35% (n = 15) of Salmonella isolates produced biofilms; however, none of the IncI1-positive transconjugants produced increased biofilms compared to the recipient. Approximately 65% (n = 28) of isolates and 67% (n = 8) of IncI1-positive transconjugants were able to inhibit growth of at least one E. coli strain; however, none inhibited the growth of strains from species other than E. coli.

Research paper thumbnail of Bacterial Populations Associated with Smokeless Tobacco Products

Research paper thumbnail of Molecular Characterization of Salmonella enterica Serovars Isolated from a Turkey Production Facility in the Absence of Selective Antimicrobial Pressure

Research paper thumbnail of Insights into potential pathogenesis mechanisms associated with Campylobacter jejuni-induced abortion in ewes

Research paper thumbnail of Phenotypic and Genotypic Diversity of Thermophilic Campylobacter spp. in Commercial Turkey Flocks: A Longitudinal Study

Poultry are recognized as a main reservoir of Campylobacter spp. However, longitudinal studies in... more Poultry are recognized as a main reservoir of Campylobacter spp. However, longitudinal studies investigating the persistence of Campylobacter on commercial meat turkeys are rare. The objectives of this study were to determine the prevalence, antimicrobial susceptibility, and persistence of genotypically related strains of Campylobacter spp. recovered from three commercial turkey farms in Ohio belonging to a single producer. Eight hundred ten samples were collected from birds aged 1 week to slaughter, consisting of 750 fecal droppings and 60 ceca at slaughter. Overall Campylobacter prevalence was 55.9%. Multiplex polymerase chain reaction (PCR) confirmed 72.3% of all isolates as C. coli, 5.3% as C. jejuni, 10.6% as both, and 11.9% as other Campylobacter spp. PCR restriction fragment length polymorphism of the flaA gene subtyping detected 70 types-62 for C. coli and 8 for C. jejuni isolates-with most (80%) of flaA-types constituting farm homogeneous groups. Multilocus sequence typing of 99 selected Campylobacter isolates resulted in 23 sequence types (STs), consisting of 8 STs for C. jejuni and 15 STs for C. coli isolates. Six novel STs-four for C. jejuni and two-for C. coli, were detected. In a subset of isolates (n = 98) tested for antimicrobial resistance, the most common resistance was to tetracycline (95%), followed by azithromycin (43%), while 42% and 18% of the isolates were resistant to ciprofloxacin and erythromycin, respectively. All isolates were susceptible to florfenicol. C. coli isolates displayed a higher proportion of resistance than C. jejuni to most antimicrobials. This study highlights the high prevalence, genotypic diversity, and antimicrobial resistance of Campylobacter spp. in commercial turkey from farm to slaughter.

Research paper thumbnail of The impairment of methylmenaquinol:fumarate reductase affects hydrogen peroxide susceptibility and accumulation in Campylobacter jejuni

The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respirator... more The methylmenaquinol:fumarate reductase (Mfr) of Campylobacter jejuni is a periplasmic respiratory (redox) protein that contributes to the metabolism of fumarate and displays homology to succinate dehydrogenase (Sdh). Since chemically oxidized redox-enzymes, including fumarate reductase and Sdh, contribute to the generation of oxidative stress in Escherichia coli, we assessed the role of Mfr in C. jejuni after exposure to hydrogen peroxide (H 2 O 2 ). Our results show that a Mfr mutant (ΔmfrA) strain was less susceptible to H 2 O 2 as compared to the wildtype (WT). Furthermore, the H 2 O 2 concentration in the ΔmfrA cultures was significantly higher than that of WT after exposure to the oxidant. In the presence of H 2 O 2 , catalase (KatA) activity and katA expression were significantly lower in the ΔmfrA strain as compared to the WT. Exposure to H 2 O 2 resulted in a significant decrease in total intracellular iron in the ΔmfrA strain as compared to WT, while the addition of iron to the growth medium mitigated H 2 O 2 susceptibility and accumulation in the mutant. The ΔmfrA strain was significantly more persistent in RAW macrophages as compared to the WT. Scanning electron microscopy showed that infection with the ΔmfrA strain caused prolonged changes to the macrophages' morphology, mainly resulting in spherical-shaped cells replete with budding structures and craters. Collectively, our results suggest a role for Mfr in maintaining iron homeostasis in H 2 O 2 stressed C. jejuni, probably via affecting the concentrations of intracellular iron.

Research paper thumbnail of Respiratory proteins contribute differentially to Campylobacter jejuni's survival and in vitro interaction with hosts' intestinal cells

The genetic features that facilitate Campylobacter jejuni's adaptation to a wide range of environ... more The genetic features that facilitate Campylobacter jejuni's adaptation to a wide range of environments are not completely defined. However, whole genome expression studies showed that respiratory proteins (RPs) were differentially expressed under varying conditions and stresses, suggesting further unidentified roles for RPs in C. jejuni's adaptation. Therefore, our objectives were to characterize the contributions of selected RPs to C. jejuni's ikey survival phenotypes under different temperature (37°C vs. 42°C) and oxygen (microaerobic, ambient, and oxygen-limited/anaerobic) conditions and ii-its interactions with intestinal epithelial cells from disparate hosts (human vs. chickens).

Research paper thumbnail of An evaluation of the effect of sodium bisulfate as a feed additive on Salmonella enterica serotype Enteritidis in experimentally infected broilers

Research paper thumbnail of Evaluating the Occurrence of Host-Specifi c Bacteroidales, General Fecal Indicators, and Bacterial Pathogens in a Mixed-Use Watershed

Fecal contamination of water is very common, and, in the United States, prevention is complicated... more Fecal contamination of water is very common, and, in the United States, prevention is complicated by the colossal span of waterways (>3.5 million miles), heterogeneous sources of pollution, and competing interests in water monitoring. Th e focus of this study was the Upper Sugar Creek Watershed, a mixed-use watershed with many headwater streams and one of the most contaminated waterways in Ohio. Quantitative polymerase chain reaction (qPCR) and hostspecifi c PCR for Bacteroidales were evaluated for the potential to discern sources of fecal contamination. Pathogen-specifi c qPCR and culturable Escherichia coli by most probable number (MPN) were compared at 21 established water quality monitoring sites in the watershed headwaters. Lower numbers of ruminantspecifi c Bacteroidales markers were detected in the base fl ow water samples compared with the human-specifi c Bacteroidales marker, suggesting the presence of hotspots of human fecal contamination. Bacteroidales qPCR and E. coli MPN showed signifi cant correlation (R 2 = 0.57; P < 0.001). Correlation between general fecal indicator and pathogen concentrations was weak or nonexistent. Coexistence of Salmonella and human-specifi c Bacteroidales was common (P = 0.015). Bacteroidales qPCR may have a greater potential for predicting fecal contamination due to its sensitivity, rapid analysis, and availability of host-specifi c assays. However, the lack of a strong correlation between pathogens and general fecal indicators suggests that assessment of health risk associated with fecal contamination will require a complement of approaches.

Research paper thumbnail of Molecular Epidemiology and Public Health Relevance of Campylobacter Isolated from Dairy Cattle and European Starlings in Ohio, USA

Dairy cattle serve as a potential source for Campylobacter infection in humans. Outbreaks associa... more Dairy cattle serve as a potential source for Campylobacter infection in humans. Outbreaks associated with consumption of either Campylobacter contaminated raw milk or contaminated milk after treatment were previously recorded in the United States. Further, starlings have been implicated in the spread of bacterial pathogens among livestock. Here, we determined the prevalence, genotypic, and phenotypic properties of Campylobacter isolated from fecal samples of dairy cattle and starlings found on the same establishment in northeastern Ohio. Campylobacter were detected in 83 (36.6%) and 57 (50.4%) out of 227 dairy and 113 starling fecal samples, respectively. Specifically, 79 C. jejuni, five C. coli, and two other Campylobacter spp. were isolated from dairy feces, while all isolates from starlings (n = 57) were C. jejuni. Our results showed that the prevalence of C. jejuni in birds was significantly ( p < 0.01) higher than that in dairy cattle. The pulsed-field gel electrophoresis analysis showed that C. jejuni were genotypically diverse and host restricted; however, there were several shared genotypes between dairy cattle and starling isolates. Likewise, many shared clonal complexes (CC) between dairy cattle and starlings were observed by multilocus sequence typing (MLST) analysis. As in humans, both in cattle and starlings, the CC 45 and CC 21 were the most frequently represented CCs. As previously reported, CC 177 and CC 682 were restricted to the bird isolates, while CC 42 was restricted to dairy cattle isolates. Further, two new sequence types (STs) were detected in C. jejuni from dairy cattle. Interestingly, cattle and starling C. jejuni showed high resistance to multiple antimicrobials, including ciprofloxacin, erythromycin, and gentamicin. In conclusion, our results highlight starlings as potential reservoirs for C. jejuni, and they may play an important role in the epidemiology of clinically important C. jejuni in dairy population.

Research paper thumbnail of Upper Sugar Creek Watershed, Ohio: A Model Watershed for Study of Pathogen Origin, Fate and Transport

Research paper thumbnail of Occurrence of the invasion associated marker (iam) in Campylobacter jejuni isolated from cattle

Research paper thumbnail of Genotypic and Phenotypic Properties of Cattle-Associated Campylobacter and Their Implications to Public Health in the USA

Since cattle are a major source of food and the cattle industry engages people from farms to proc... more Since cattle are a major source of food and the cattle industry engages people from farms to processing plants and meat markets, it is conceivable that beef-products contaminated with Campylobacter spp. would pose a significant public health concern. To better understand the epidemiology of cattle-associated Campylobacter spp. in the USA, we characterized the prevalence, genotypic and phenotypic properties of these pathogens. Campylobacter were detected in 181 (19.2%

Research paper thumbnail of Polyphosphate Kinase 2: A Novel Determinant of Stress Responses and Pathogenesis In Campylobacter Jejuni

Research paper thumbnail of Use of Bioluminescence Imaging to Monitor Campylobacter Survival In Chicken Litter

Journal of Applied …

Aim: The aim of this study was to develop a novel approach for characterizing the growth and per... more Aim: The aim of this study was to develop a novel approach for characterizing the growth and persistence of Campylobacter in different poultry-rearing environments. Specifically, we constructed bioluminescent Campylobacter strains and used them to monitor the survival of these pathogens in litter (bedding) material.Methods and Results: We inserted shuttle plasmids carrying the luminescence genes (luxCDABE) into C. jejuni and C. coli to construct bioluminescent strains of these pathogens. The strains were spiked into microcosms containing samples of litter-washings and dry litter collected from different enclosures that housed broiler chickens. Our results show that C. jejuni and C. coli survived for at least 20 days in reused (old) litter while the growth of these pathogens was inhibited in clean (new) litter. Furthermore, our results suggest that the availability of nutrients and the condition of the litter (reused vs new) are important factors in the persistence of these pathogens.Conclusions: Reused litter can potentially predispose chickens to Campylobacter contamination and maintaining clean litter might reduce the incidences of colonization with these pathogens.Significance and Impact of the Study: Bioluminescence provided a simple, sensitive, and rapid approach for analysing the growth dynamics of Campylobacter. Using this technology, we highlighted the potential role of litter material in maintaining these pathogens in the chicken environment.