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House Sparrows Do Not Constitute a Significant Salmonella Typhimurium Reservoir across Urban Gradients in Flanders, Belgium. PLoS One 2016; 11:e0155366. [PMID: 27168186 PMCID: PMC4864353 DOI: 10.1371/journal.pone.0155366] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 04/27/2016] [Indexed: 11/20/2022] Open
Abstract
In recent decades major declines in urban house sparrow (Passer domesticus) populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013–2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naïve hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: <1.3%) of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.
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Chon JW, Jung HI, Kuk M, Lim JS, Seo KH, Kim SK. Microbiological Evaluation of Pork and Chicken By-Products in South Korea. J Food Prot 2016; 79:715-22. [PMID: 27296417 DOI: 10.4315/0362-028x.jfp-15-395] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study, we aimed to evaluate the microbiological risk of pork and chicken by-products by enumerating indicator bacteria (total aerobic bacteria, coliforms, and Escherichia coli) and identifying pathogens such as Campylobacter and Salmonella. The antibiotic resistance of pathogenic isolates was determined, and molecular subtyping was performed using automated repetitive sequence-based PCR (rep-PCR). Pork and chicken by-products were collected from 10 processing plants. The mean numbers of total aerobic bacteria, coliforms, and E. coli from 95 pork by-product samples and 64 chicken by-product samples were 5.1, 3.6, and 2.4 log CFU/g and 4.5, 3.0, and 1.8 log CFU/g, respectively. The numbers of indicator bacteria in the gastrointestinal tract (small intestine, large intestine, and gizzard) were significantly higher than those in other organs. Salmonella and Campylobacter species were detected in 3 and 5 of 95 pork by-product samples and in 6 and 3 of 64 chicken by-product samples, respectively. Four of 9 Salmonella isolates examined were resistant to eight antibiotics, and each of these resistant strains produced an extended-spectrum β-lactamase. Most Campylobacter isolates were resistant to tetracycline (7 of 8 strains) and quinolones (7 of 8 strains). The similarity in rep-PCR patterns among Salmonella isolates was more closely associated with serotype than with the processing plant and type of meat. Conversely, the rep-PCR patterns of Campylobacter isolates were specific to the processing plant. Our findings could help agencies develop regulations for protection from foodborne bacterial infections arising from animal by-products.
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Affiliation(s)
- Jung-Whan Chon
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea; U.S. Food and Drug Administration, Division of Microbiology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Hae-In Jung
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Min Kuk
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jong-Soo Lim
- Center for One Health, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Kun-Ho Seo
- Center for One Health, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Soo-Ki Kim
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
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Chon JW, Jung HI, Kuk M, Kim YJ, Seo KH, Kim SK. High Occurrence of Extended-Spectrum β-Lactamase-ProducingSalmonellain Broiler Carcasses from Poultry Slaughterhouses in South Korea. Foodborne Pathog Dis 2015; 12:190-6. [DOI: 10.1089/fpd.2014.1847] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jung-Whan Chon
- KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
| | - Hae-In Jung
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Min Kuk
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
| | - Young-Ji Kim
- KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
| | - Kun-Ho Seo
- KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul, Republic of Korea
| | - Soo-Ki Kim
- Department of Animal Science and Technology, College of Animal Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea
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Luo Z, Gu G, Giurcanu MC, Adams P, Vellidis G, van Bruggen AHC, Wright AC. Development of a novel cross-streaking method for isolation, confirmation, and enumeration of Salmonella from irrigation ponds. J Microbiol Methods 2014; 101:86-92. [PMID: 24732066 DOI: 10.1016/j.mimet.2014.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 03/24/2014] [Indexed: 10/25/2022]
Abstract
The 2013 Produce Safety Rules in Food Safety Modernization Act (FSMA) require regular testing for generic Escherichia coli in agricultural water intended for pre-harvest contact with the edible portion of fresh produce. However, the use of fecal contamination indicators frequently does not correctly reflect distribution of foodborne pathogens such as Salmonella enterica, and ensuring food safety may require direct detection and enumeration of pathogens in agricultural settings. Herein we report the evaluation of different cost-effective methods for quantification, isolation, and confirmation of Salmonella in irrigation pond water and sediment samples. A most probably number (MPN) dual enrichment culture method was used in combination with differential and selective agars, XLT4 and CHROMagar™ Salmonella plus (CSP). The necessity for PCR confirmation was evaluated, and methods were compared by cost and performance measures (i.e., sensitivity, specificity, positive predictive value, and negative predictive value). Statistical analyses showed that using XLT4 as the initial selective agar to isolate Salmonella colonies improved recovery compared to CSP agar; however, PCR confirmation was required to avoid false positive results on either agar. Therefore, a novel cross-streaking method utilizing CHROMagar™ agar for individual colony confirmation of Salmonella presence/absence on XLT4 was developed. This method classifies the colony as positive if typical Salmonella appearance is observed on both agars. Statistical analysis showed that this method was as effective as PCR for species confirmation of pure individual strains isolated from enrichment cultures (sensitivity=0.99, specificity=1.00, relative to PCR). This method offers a cost-effective alternative to PCR that would increase the capacity and sensitivity of Salmonella evaluation.
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Affiliation(s)
- Zhiyao Luo
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL 32611, USA
| | - Ganyu Gu
- Emerging Pathogens Institute and Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Mihai C Giurcanu
- Department of Statistics, IFAS, University of Florida, Gainesville, FL 32611, USA
| | - Paige Adams
- Biological & Agricultural Engineering Department, University of Georgia, Tifton, GA 31793, USA
| | - George Vellidis
- Biological & Agricultural Engineering Department, University of Georgia, Tifton, GA 31793, USA
| | - Ariena H C van Bruggen
- Emerging Pathogens Institute and Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Anita C Wright
- Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL 32611, USA.
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Zheng Q, Bustandi C, Yang Y, Schneider KR, Yuk HG. Comparison of enrichment broths for the recovery of healthy and heat-injured Salmonella typhimurium on raw duck wings. J Food Prot 2013; 76:1963-8. [PMID: 24215702 DOI: 10.4315/0362-028x.jfp-13-041] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was performed to optimiz eSalmonella Typhimurium recovery from raw duck wings with five nonselective broths (buffered peptone water, tryptic soy broth, lactose broth, universal preenrichment broth, nutrient broth) and four selective broths (selenite broth, BAX System MP media [MP], Salmonella AD media [AD], ONE broth-Salmonella [OB]). Healthy or heat-injured (50 and 85% injury) cells were inoculated at a level of 10(2), 10(1), or 10(0) CFU/25 g on raw duck wings. Growth was modeled using DMfit with four growth parameters: lag-phase duration, maximum growth rate, doubling time, and maximum population density. Most enrichments were able to recover Salmonella Typhimurium to greater than 6 log CFU/ml. AD, MP, and OB had significantly (P < 0.05) higher maximum growth rate (0.9 to 1.0/h) and lower doubling time (0.7 to 0.8 h). Buffered peptone water, AD, MP, and OB recovered healthy and 50%-injured cells at low inoculum levels to more than 6.0 log CFU/ml; OB achieved the greatest recovery (7.6 and 7.9 log CFU/ml), following 24 h of incubation. The 85%-injured cells at 10(0) and 10(1) CFU/25 g, however, were only recovered in OB, reaching 7.3 and 7.5 log CFU/ml, respectively. These results suggest that OB may be an appropriate enrichment broth for the recovery of Salmonella Typhimurium from raw duck wings in standard diagnostic tests or other rapid detection methods, to avoid false-negative results.
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Affiliation(s)
- Qianwang Zheng
- Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
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