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Roldan-Henao M, Dalsgaard A, Cardona-Castro N, Restrepo-Rivera L, Veloza-Angulo LC, Alban L. Pilot study of the productivity and Salmonella seroprevalence in pigs administered organic acids. Front Vet Sci 2023; 10:1123137. [PMID: 36937024 PMCID: PMC10020582 DOI: 10.3389/fvets.2023.1123137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Control of Salmonella in pig/pork production is important to protect public health because pork is one of the main sources of human infection. Moreover, antimicrobial use in pig farms should be kept low to minimize development and transmission of antimicrobial resistance. This pilot study evaluated the productivity and Salmonella seroprevalence in pigs administered organic acids (OA) compared to pigs given growth promoters in one farm in Antioquia, Colombia. Two groups each consisting of 60 pigs of 6-weeks of age were studied for 4 months. One group was provided feed and water with OA (Selko pH® and Selacid®), whereas the other group (control) received antimicrobial growth promoters according to routine feeding practices (tylosin and zinc bacitracin). Blood samples were taken three times (T1-T3) and pigs were weighted five times to calculate daily weight gain (DWG) and feed conversion ratio (FCR). Initially when the pigs were 6 weeks old (T1), the Salmonella seroprevalence was 1.7% in both groups. When the pigs were 11 weeks old (T2), the seroprevalence was significantly lower in pigs provided OA compared to the control group (19 vs. 47%, P < 0.001), whereas when the pigs were 23 weeks old (T3), the seroprevalence did not differ between the groups (62 vs. 77%; P = 0.075). The cumulative DWG was significantly higher in the intervention group than in the control group (713 vs. 667 g/day; P < 0.001). The cumulative FCR did not differ between groups (2.80 vs. 2.77; P = 0.144). The pilot study indicates that cleaning the water pipes and administrating OA improve productivity in pigs and delay exposure to Salmonella spp. when compared with growth promoters. Thus, OA could replace antimicrobial growth promoters and reduce antimicrobial use and resistance. However, the study should be repeated before firmer conclusions can be drawn.
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Affiliation(s)
- Manuela Roldan-Henao
- Department of Veterinary and Animal Sciences, CES University, Medellin, Colombia
- *Correspondence: Manuela Roldan-Henao
| | - Anders Dalsgaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nora Cardona-Castro
- Instituto Colombiano de Medicina Tropical, CES University, Medellin, Colombia
| | | | | | - Lis Alban
- Department of Veterinary and Animal Sciences, University of Copenhagen, Copenhagen, Denmark
- Department for Food Safety and Veterinary Issues, Danish Agriculture & Food Council, Copenhagen, Denmark
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2
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Ye Q, Shang Y, Chen M, Pang R, Li F, Wang C, Xiang X, Zhou B, Zhang S, Zhang J, Wu S, Xue L, Ding Y, Wu Q. Identification of new serovar-specific detection targets against salmonella B serogroup using large-scale comparative genomics. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107862] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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3
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Santos PDM, Widmer KW, Rivera WL. PCR-based detection and serovar identification of Salmonella in retail meat collected from wet markets in Metro Manila, Philippines. PLoS One 2020; 15:e0239457. [PMID: 32997676 PMCID: PMC7526908 DOI: 10.1371/journal.pone.0239457] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 09/08/2020] [Indexed: 11/27/2022] Open
Abstract
This study aimed to detect Salmonella from retail meat collected from nine wet markets in Metro Manila, and identify the subtypes of Salmonella isolates using molecular serotyping assays from previously developed primers. Of the 720 collected meat samples, 57.64% were found to be Salmonella-contaminated. The most predominant serogroup was Salmonella O:3, and Salmonella serogroups O:4, O:6,7, O:8, O:9, and undetermined serogroups were also found. Most frequently detected isolates in bovine meat were S. 3:e,h:1,6 (putative identity: S. Anatum) and S: 4:e,h:1,2 (putative identity: S. Saintpaul), in porcine meat was S. 3:e,h:1,6 (putative identity: S. Anatum), and S. 8:i:z6 (putative identity: S. Kentucky) was common in poultry products. This study also demonstrated retail meat samples were contaminated with multiple Salmonella serogroups and serovars. This is the first Philippine study that utilized PCR-based assays to characterize Salmonella isolates down to a serovar level and provides baseline information regarding Salmonella prevalence and serovar distribution in retail meat. Molecular serotyping performed in this study can be used as an alternative approach to traditional serotyping in surveillance of Salmonella in the Philippines since the latter is expensive, time-consuming, and requires skilled technicians.
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Affiliation(s)
- Pauline Dianne M. Santos
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
| | - Kenneth W. Widmer
- International Environmental Research Institute, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Windell L. Rivera
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City, Philippines
- * E-mail:
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4
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Application of machine learning algorithm and modified high resolution DNA melting curve analysis for molecular subtyping of Salmonella isolates from various epidemiological backgrounds in northern Thailand. World J Microbiol Biotechnol 2020; 36:103. [PMID: 32613458 DOI: 10.1007/s11274-020-02874-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 06/21/2020] [Indexed: 10/23/2022]
Abstract
Food poisoning from consumption of food contaminated with non-typhoidal Salmonella spp. is a global problem. A modified high resolution DNA melting curve analysis (m-HRMa) was introduced to provide effective discrimination among closely related HRM curves of amplicons generated from selected Salmonella genome sequences enabled Salmonella spp. to be classified into discrete clusters. Combination of m-HRMa with serogroup identification (ms-HRMa) helped improve assignment of Salmonella spp. into clusters. In addition, a machine learning (dynamic time warping) algorithm (DTW) was employed to provide a simple and rapid protocol for clustering analysis as well as to create phylogeny tree of Salmonella strains (n = 40) collected from home, farms and slaughter houses in northern Thailand. Applications of DTW and ms-HRMa clustering analyses were capable of generating molecular signatures of the Salmonella isolates, resulting in 25 ms-HRM and 28 DTW clusters compared to 14 clusters from a standard HRM analysis, and the combination of both analyses permitted molecular subtyping of each Salmonella isolate. Results from DTW and ms-HRMa cluster analyses were in good agreement with that obtained from enterobacterial repetitive intergenic consensus sequence PCR clustering. While conventional serotyping of Clusters 1 and 2 revealed six different Salmonella serotypes, the majority being S. Weltevraden, the new Salmonella subtyping protocol identified five S. Weltevraden subtypes with S.Weltevreden subtype DTW4-M1 being predominant. Based on knowledge of the sources of Salmonella subtypes, transmission of S. Weltevraden in northern Thailand was likely to be farm-to-farm through contaminated chicken stool. In conclusion, the rapid, robust and specific Salmonella subtyping developed in the study can be performed in a local setting, enabling swift control and preventive measures to be initiated against potential epidemics of salmonellosis.
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5
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Ren J, Man Y, Li A, Liang G, Jin X, Pan L. Detection of
Salmonella enteritidis
and
Salmonella typhimurium
in foods using a rapid, multiplex real‐time recombinase polymerase amplification assay. J Food Saf 2020. [DOI: 10.1111/jfs.12784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Junan Ren
- Beijing Food & Wine Inspection and Testing Station Beijing China
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
| | - Yan Man
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
| | - An Li
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
| | - Gang Liang
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
| | - Xinxin Jin
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
| | - Ligang Pan
- Beijing Research Center for Agricultural Standards and Testing, Beijing Academy of Agriculture and Forestry Sciences Beijing China
- Risk Assessment Lab for Agro‐ products (Beijing), Ministry of Agriculture Beijing China
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6
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Zuo L, Jiang M, Jiang Y, Shi X, Li Y, Lin Y, Qiu Y, Deng Y, Li M, Lin Z, Liao Y, Xie J, Li Q, Hu Q. Multiplex ligation reaction based on probe melting curve analysis: a pragmatic approach for the identification of 30 common Salmonella serovars. Ann Clin Microbiol Antimicrob 2019; 18:39. [PMID: 31805936 PMCID: PMC6894471 DOI: 10.1186/s12941-019-0338-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/18/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND While Salmonella serotyping is of paramount importance for the disease intervention of salmonellosis, a fast and easy-to-operate molecular serotyping solution remains elusive. We have developed a multiplex ligation reaction based on probe melting curve analysis (MLMA) for the identification of 30 common Salmonella serovars. METHODS Serovar-specific primers and probes were designed based on a comparison of gene targets (wzx and wzy encoding for somatic antigen biosynthesis; fliC and fljB for flagellar antigens) from 5868 Salmonella genomes. The ssaR gene, a type III secretion system component, was included for the confirmation of Salmonella. RESULTS All gene targets were detected and gave expected Tm values during assay evaluation. Cross reactions were not demonstrated between the 30 serovars (n = 211), or with an additional 120 serovars (n = 120) and other Enterobacteriaceae (n = 3). The limit of identification for all targets ranged from using 1.2 ng/μL to 1.56 ng/μL of DNA. The intra- and inter-assay standard deviations and the coefficients of variation were no more than 0.5 °C and less than 1% respectively, indicating high reproducibility. From consecutive outpatient stool samples (n = 3590) collected over a 10-month period at 11 sentinel hospitals in Shenzhen, China, we conducted a multicenter study using the traditional Salmonella identification workflow and the MLMA assay workflow in parallel. From Salmonella isolates (n = 496, 13.8%) derived by both workflows, total agreement (kappa = 1.0) between the MLMA assay and conventional serotyping was demonstrated. CONCLUSIONS With an assay time of 2.5 h, this simple assay has shown promising potential to provide rapid and high-throughput identification of Salmonella serovars for clinical and public health laboratories to facilitate timely surveillance of salmonellosis.
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Affiliation(s)
- Le Zuo
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Min Jiang
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Yixiang Jiang
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Xiaolu Shi
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Yinghui Li
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Yiman Lin
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Yaqun Qiu
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Yinhua Deng
- College of Life Science, Sichuan University, Chengdu, China
| | - Minxu Li
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zeren Lin
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Yiqun Liao
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Jianbin Xie
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China
| | - Qingge Li
- School of Life Sciences, Xiamen University, Xiamen, China
| | - Qinghua Hu
- Shenzhen Center for Disease Control and Prevention, 8 Longyuan Road, Nanshan District, Shenzhen, China.
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7
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Kasturi KN. A real-time PCR for rapid identification of Salmonella enterica Gaminara serovar. J Microbiol Methods 2019; 169:105729. [PMID: 31711901 DOI: 10.1016/j.mimet.2019.105729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/13/2019] [Accepted: 09/21/2019] [Indexed: 12/17/2022]
Abstract
Salmonella is one of the leading causes of foodborne illnesses in the USA. When a Salmonella outbreak occurs, rapid identification of the causative serovar is important for tracing the source of contamination and for preventing the further spread of the illness. Each serovar is characterized by the presence of a group-specific somatic O-antigen(s) and an assortment of flagellar phase-1 and phase-2 antigens. As the traditional serotyping protocol is time consuming, labor intensive, and expensive, faster and less expensive molecular diagnostic methods are needed. This report outlines the development of a rapid multiplex real-time PCR procedure that facilitates the identification of Salmonella serogroup I and the serovars of the group. Using Salmonella Gaminara serovar (O16:d:1,7) as an example, first the gene(s) responsible for expression of the somatic O antigen, O16, and the nucleotide sequence of the variable-region of genes encoding the flagellar phase-1 (d) and phase-2 (1,7) antigens were identified. Then, a multiplex real-time PCR was designed that incorporated primers and probes specific for the three target genes and confirmed the specificity. The assay had 100% inclusivity for all three gene targets, detecting 2 genomic DNA copies of O16 and 1,7 gene targets and 10 copies of d gene target. Importance: Rapid molecular methods to identify Salmonella serovars should increase the precision of routine surveillance of clinically important serovars and promote public health.
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Affiliation(s)
- Kuppuswamy N Kasturi
- U. S. Food and Drug Administration, Office of Regulatory Affairs, Office of Regulatory Science, Northeast Food and Feed Laboratory, Jamaica, New York 11433, USA.
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SEO BJ, SONG ET, LEE K, KIM JW, JEONG CG, MOON SH, SON JS, KANG SH, CHO HS, JUNG BY, KIM WI. Evaluation of the broad-spectrum lytic capability of bacteriophage cocktails against various Salmonella serovars and their effects on weaned pigs infected with Salmonella Typhimurium. J Vet Med Sci 2018; 80:851-860. [PMID: 29618667 PMCID: PMC6021886 DOI: 10.1292/jvms.17-0501] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 03/19/2018] [Indexed: 11/22/2022] Open
Abstract
The broad-spectrum lytic capability of Salmonella bacteriophages against various Salmonella species was evaluated to determine their potential as an alternative for antibiotics, and the safety and preventive effects of the bacteriophages were assessed on mice and pigs. Four bacteriophage cocktails were prepared using 13 bacteriophages, and the lytic capability of the four bacteriophage cocktails was tested using Salmonella reference strains and field isolates. Bacteriophage cocktail C (SEP-1, SGP-1, STP-1, SS3eP-1, STP-2, SChP-1, SAP-1, SAP-2; ≥109 pfu/ml) showed the best lytic activity against the Salmonella reference strains (100% of 34) and field isolates (92.5% of 107). Fifty mice were then orally inoculated with bacteriophage cocktail C to determine the distribution of bacteriophages in various organs, blood and feces. The effects of bacteriophages on Salmonella infection in weaned pigs (n=15) were also evaluated through an experimental challenge with Salmonella Typhimurium after treatment with bacteriophage cocktail C. All mice exhibited distribution of the bacteriophages in all organs, blood and feces until 15 days post infection (dpi). After 35 dpi, bacteriophages were not detected in any of these specimens. As demonstrated in a pig challenge study, treatment with bacteriophage cocktail C reduced the level of Salmonella shedding in feces. The metagenomic analyses of these pig feces also revealed that bacteriophage treatment decreased the number of species of the Enterobacteriaceae family without significant disturbance to the normal fecal flora. This study showed that bacteriophages effectively controlled Salmonella in a pig challenge model and could be a good alternative for antibiotics to control Salmonella infection.
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Affiliation(s)
- Byoung-Joo SEO
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
| | - Eu-Tteum SONG
- Bacterial Disease Division, Animal and Plant Quarantine
Agency, Gimcheon 39660, Republic of Korea
| | - Kichan LEE
- Bacterial Disease Division, Animal and Plant Quarantine
Agency, Gimcheon 39660, Republic of Korea
| | - Jong-Won KIM
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
| | - Chang-Gi JEONG
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
| | - Sung-Hyun MOON
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
| | - Jee Soo SON
- iNtRON Biotechnology, Inc., Room 903, JungAng Induspia V,
137, Sagimakgol-ro, Jungwon-gu, Seongnam-si, Gyeonggi-do, 13202, Republic of Korea
| | - Sang Hyeon KANG
- iNtRON Biotechnology, Inc., Room 903, JungAng Induspia V,
137, Sagimakgol-ro, Jungwon-gu, Seongnam-si, Gyeonggi-do, 13202, Republic of Korea
| | - Ho-Seong CHO
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
| | - Byeong Yeal JUNG
- Bacterial Disease Division, Animal and Plant Quarantine
Agency, Gimcheon 39660, Republic of Korea
| | - Won-Il KIM
- College of Veterinary Medicine, Chonbuk National University,
Iksan 54596, Republic of Korea
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9
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Borah P, Porwollik S, Desai P, Nayak P, Borah PP, Cheng P, McClelland M. A simplified multiplex PCR-based typing method for common Salmonella enterica serovars supported by online server-based detection system. Indian J Med Res 2017; 146:272-280. [PMID: 29265030 PMCID: PMC5761039 DOI: 10.4103/ijmr.ijmr_1258_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Background & objectives: A rapid and simple alternative method is needed to replace the laborious, time-consuming Salmonella serotyping. The objective of the present study was to improve and simplify a previously reported multiplex polymerase chain reaction (PCR)-based method and to create an online server to enable rapid determination of serovars. Methods: A method of multiplex PCR-based genome typing (MPGT) was standardized using 59 Salmonella isolates of 31 serovars. Several previously reported primers were modified to obtain a more accurate performance. The screen was separated into four different multiplex reactions distinguishable on standard electrophoresis. A blind study was subsequently performed with 81 isolates of 10 serovars most prevalent in India. Whole genome information from 440 Salmonella isolates was used to confirm the usefulness of this method and concurrence of in silico predictions and PCR results were investigated. A public server (http://www.mpgt-salmonella.res.in) was established for data storage and determination of closest previously observed Salmonella isolates based on obtained MPGT patterns. Results: The 16 target genes amplified showed variability in their presence in strains from different serotypes. Hence, identical amplification patterns suggested genetic relatedness of strains and usually identical serological behaviour. The observed absence/presence patterns of genes were converted to an MPGT code. Altogether, 83 different codes were predicted in silico based on the whole genome information of 440 strains. Results confirmed that major serovars usually displayed unique MPGT codes. Interpretation & conclusions: The multiplex PCR assay resulted in specific binary codes for isolates from each of the 31 Salmonella serovars tested. The online server allowed the user to compare obtained PCR results with stored previous patterns. Simplicity, speed and cost-effectiveness make this tool useful for quick outbreak management.
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Affiliation(s)
- Probodh Borah
- Department of Microbiology, College of Veterinary Science, Assam Agricultural University, Guwahati, India
| | - Steffen Porwollik
- Deparment of Microbiology & Molecular Genetics, University of California, Irvine, USA
| | - Prerak Desai
- Deparment of Microbiology & Molecular Genetics, University of California, Irvine, USA
| | - Prakash Nayak
- Department of Bioinformatics Centre, College of Veterinary Science, Assam Agricultural University, Guwahati, India
| | - Partha Pratim Borah
- Department of Animal Biotechnology, College of Veterinary Science, Assam Agricultural University, Guwahati, India
| | - Pui Cheng
- Deparment of Microbiology & Molecular Genetics, University of California, Irvine, USA
| | - Michael McClelland
- Deparment of Microbiology & Molecular Genetics, University of California, Irvine, USA
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Iwu CJ, Iweriebor BC, Obi LC, Basson AK, Okoh AI. Multidrug-Resistant Salmonella Isolates from Swine in the Eastern Cape Province, South Africa. J Food Prot 2016; 79:1234-9. [PMID: 27357044 DOI: 10.4315/0362-028x.jfp-15-224] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The exposure of farm animals to antimicrobials for treatment, prophylaxis, or growth promotion can select for resistant bacteria that can be transmitted to humans, and Salmonella as an important zoonotic pathogen can act as a potential reservoir of antimicrobial resistance determinants. We assessed the antibiogram profiles of Salmonella species isolated from pig herds in two commercial farms in South Africa. Two hundred fifty-eight presumptive Salmonella isolates were recovered from the fecal samples of 500 adult pigs. Specific primers targeting Salmonella serogroups A, B, C1, C2, and D were used to determine the prevalence of different serogroups. Only serogroup A (n = 48) was detected, while others were not. Antimicrobial susceptibility of the confirmed Salmonella serogroup A isolates was performed by using the disk diffusion method against a panel of 18 antibiotics. All the 48 isolates were resistant to tetracycline and oxytetracycline, while 75% were resistant to ampicillin, sulphamethoxazole-trimethoprim, nalidixic acid, and streptomycin. All the isolates exhibited multidrug resistance, with the predominant phenotype being against 11 antibiotics, and multiple antibiotic resistance index ranged between 0.3 and 0.6. The incidence of genes encoding resistance against ampicillin (ampC), tetracycline (tetA), and streptomycin (strA) were 54, 61, and 44%, respectively. We conclude that healthy pigs are potential reservoirs of multidrug-resistant Salmonella that could be transmitted to humans through the food chain and, hence, a significant public health threat.
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Affiliation(s)
- Chinwe Juliana Iwu
- South African Medical Research Council Microbial Water Quality Monitoring Centre, , University of Fort Hare, Alice 5700, Eastern Cape, South Africa; Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, Eastern Cape, South Africa.
| | - Benson Chuks Iweriebor
- South African Medical Research Council Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, Eastern Cape, South Africa;Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, Eastern Cape, South Africa
| | - Larry Chikwelu Obi
- Academic and Research Division, University of Fort Hare, Alice 5700, Eastern Cape, South Africa
| | - Albertus Kotze Basson
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa, 3886, South Africa
| | - Anthony Ifeanyi Okoh
- South African Medical Research Council Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, Eastern Cape, South Africa; Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, Eastern Cape, South Africa
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11
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Villarreal Camacho JL, Mendoza Torres E, Cadena C, Prieto J, Varela Prieto LL, Villanueva Torregroza DA. The use of factorial design, image analysis, and an efficiency calculation for multiplex PCR optimization. J Clin Lab Anal 2014; 27:249-52. [PMID: 23686781 DOI: 10.1002/jcla.21595] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 02/04/2013] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND The quality of multiplex polymerase chain reaction (PCR) assays depends on several factors. Therefore, it is important to establish the optimal conditions to achieve efficient amplification. The objective of this study was to implement a 5 × 4 factorial design combined with image analysis using agarose gels and an efficiency calculation to optimize a multiplex PCR assays for the detection of Salmonella enterica serovar typhimurium. METHODS We used 12 ng of Salmonella DNA obtained from pure cultures and applied different annealing temperatures (65°C, 64.5°C, 63.3°C, 61.4°C, or 59°C) and different MgCl2 concentrations (1 mM, 1.5 mM, 2 mM, or 2.5 mM) to amplify regions of the fliC, rfbJ, and fljB genes. The 5 × 4 factorial design was performed using Statgraphics Plus software version 5.1, and the images were analyzed using Image Lab(TM) software. RESULTS Superior amplification was obtained using an annealing temperature of 65°C and 2 mM MgCl2 . This finding was confirmed by calculating the efficiency of multiplex PCR assays (6.1%) at these conditions. CONCLUSION We propose the application of factorial design and image analysis to determine the most suitable conditions for multiplex PCR optimization.
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12
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Development of a Novel Hexa-plex PCR Method for Identification and Serotyping of Salmonella Species. Foodborne Pathog Dis 2014; 11:75-7. [DOI: 10.1089/fpd.2013.1551] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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13
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Ngoi ST, Lindstedt BA, Watanabe H, Thong KL. Molecular characterization of Salmonella enterica serovar Typhimurium isolated from human, food, and animal sources in Malaysia. Jpn J Infect Dis 2013; 66:180-8. [PMID: 23698477 DOI: 10.7883/yoken.66.180] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Salmonella Typhimurium is an important nontyphoidal Salmonella serovar associated with foodborne diseases in many parts of the world. This organism is the major causative agent of nontyphoidal salmonellosis in Malaysia. We aimed to investigate the genetic profiles of the strains isolated from clinical, zoonotic, and dietary sources in Malaysia using multilocus variable number tandem repeat analysis (MLVA) and pulsed-field gel electrophoresis (PFGE). By focusing on the 5 common variable number tandem repeat (VNTR) loci, we found that PFGE (D = 0.99) was more discriminative than MLVA (D = 0.76). The low MLVA score might be because of a lack of VNTR loci STTR6 (81.0%) and STTR10pl (76.2%). Both subtyping methods suggested that our S. Typhimurium strains were largely endemic with limited genetic variation. Furthermore, we observed that biphasic S. Typhimurium strains were dominant (99%) and multidrug resistance was prevalent (50%) within our sample pool. The most frequently observed phenotypes were resistance to compound sulfonamides (49%), tetracycline (51%), and streptomycin (52%). In this study, we documented the genetic relationship, antimicrobial resistance characteristics, and flagellar-phase dominance among S. Typhimurium strains found in Malaysia.
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Affiliation(s)
- Soo Tein Ngoi
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
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Shi C, Singh P, Ranieri ML, Wiedmann M, Moreno Switt AI. Molecular methods for serovar determination of Salmonella. Crit Rev Microbiol 2013; 41:309-25. [PMID: 24228625 DOI: 10.3109/1040841x.2013.837862] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Salmonella is a diverse foodborne pathogen, which has more than 2600 recognized serovars. Classification of Salmonella isolates into serovars is essential for surveillance and epidemiological investigations; however, determination of Salmonella serovars, by traditional serotyping, has some important limitations (e.g. labor intensive, time consuming). To overcome these limitations, multiple methods have been investigated to develop molecular serotyping schemes. Currently, molecular methods to predict Salmonella serovars include (i) molecular subtyping methods (e.g. PFGE, MLST), (ii) classification using serovar-specific genomic markers and (iii) direct methods, which identify genes encoding antigens or biosynthesis of antigens used for serotyping. Here, we reviewed reported methodologies for Salmonella molecular serotyping and determined the "serovar-prediction accuracy", as the percentage of isolates for which the serovar was correctly classified by a given method. Serovar-prediction accuracy ranged from 0 to 100%, 51 to 100% and 33 to 100% for molecular subtyping, serovar-specific genomic markers and direct methods, respectively. Major limitations of available schemes are errors in predicting closely related serovars (e.g. Typhimurium and 4,5,12:i:-), and polyphyletic serovars (e.g. Newport, Saintpaul). The high diversity of Salmonella serovars represents a considerable challenge for molecular serotyping approaches. With the recent improvement in sequencing technologies, full genome sequencing could be developed into a promising molecular approach to serotype Salmonella.
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Affiliation(s)
- Chunlei Shi
- Department of Food Science, Cornell University , Ithaca, NY , USA and
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Paião FG, Arisitides LGA, Murate LS, Vilas-Bôas GT, Vilas-Boas LA, Shimokomaki M. Detection of Salmonella spp, Salmonella Enteritidis and Typhimurium in naturally infected broiler chickens by a multiplex PCR-based assay. Braz J Microbiol 2013; 44:37-41. [PMID: 24159281 PMCID: PMC3804175 DOI: 10.1590/s1517-83822013005000002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 09/13/2012] [Indexed: 11/24/2022] Open
Abstract
The presence of Salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. A rapid method to identify and monitor Salmonella and their sorovars in farm is becoming necessary. A pre-enriched multiplex polymerase chain reaction (m-PCR) assay employing specific primers was developed and used to detect Salmonella at the genus level and to identify the Salmonella enterica serovar Enteritidis (S. Enteritidis) and Salmonella enterica serovar Typhimurium (S. Typhimurium) in broiler chicken swab samples. The method was validated by testing DNA extract from 90 fresh culture cloacal swab samples from poultry chicken cultured in phosphate buffer peptone water at 37 °C for 18 h. The final results showed the presence of Salmonella spp. in 25% of samples, S. Enteritidis was present in 12% of the Salmonella-positive samples and S. Typhimurium in 3% of the samples. The m-PCR assay developed in this study is a specific and rapid alternative method for the identification of Salmonella spp. and allowed the observation of specific serovar contamination in the field conditions within the locations where these chickens are typically raised.
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Affiliation(s)
- F G Paião
- Universidade Estadual de Londrina, Centro de Ciências Agrárias, Departamento de Ciência e Tecnologia de Alimentos, Londrina, PR, Brazil
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Abstract
We have developed a Salmonella genoserotyping array (SGSA) which rapidly generates an antigenic formula consistent with the White-Kauffmann-Le Minor scheme, currently the gold standard for Salmonella serotyping. A set of 287 strains representative of 133 Salmonella serovars was assembled to validate the array and to test the array probes for accuracy, specificity, and reproducibility. Initially, 76 known serovars were utilized to validate the specificity and repeatability of the array probes and their expected probe patterns. The SGSA generated the correct serovar designations for 100% of the known subspecies I serovars tested in the validation panel and an antigenic formula consistent with that of the White-Kauffmann-Le Minor scheme for 97% of all known serovars tested. Once validated, the SGSA was assessed against a blind panel of 100 Salmonella enterica subsp. I samples serotyped using traditional methods. In summary, the SGSA correctly identified all of the blind samples as representing Salmonella and successfully identified 92% of the antigens found within the unknown samples. Antigen- and serovar-specific probes, in combination with a pepT PCR for confirmation of S. enterica subsp. Enteritidis determinations, generated an antigenic formula and/or a serovar designation consistent with the White-Kauffmann-Le Minor scheme for 87% of unknown samples tested with the SGSA. Future experiments are planned to test the specificity of the array probes with other Salmonella serovars to demonstrate the versatility and utility of this array as a public health tool in the identification of Salmonella.
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Silva DSP, Canato T, Magnani M, Alves J, Hirooka EY, de Oliveira TCRM. Multiplex PCR for the simultaneous detection of Salmonella spp. and Salmonella Enteritidis in food. Int J Food Sci Technol 2011. [DOI: 10.1111/j.1365-2621.2011.02646.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pui CF, Wong WC, Chai LC, Lee HY, Noorlis A, Zainazor TCT, Tang JYH, Ghazali FM, Cheah YK, Nakaguchi Y, Nishibuchi M, Radu S. Multiplex PCR for the concurrent detection and differentiation of Salmonella spp., Salmonella Typhi and Salmonella Typhimurium. Trop Med Health 2011; 39:9-15. [PMID: 22028607 PMCID: PMC3153144 DOI: 10.2149/tmh.2010-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/02/2011] [Indexed: 11/11/2022] Open
Abstract
Salmonellosis outbreaks involving typhoid fever and human gastroenteritis are important diseases in tropical countries where hygienic conditions are often not maintained. A rapid and sensitive method to detect Salmonella spp., Salmonella Typhi and Salmonella Typhimurium is needed to improve control and surveillance of typhoid fever and Salmonella gastroenteritis. Our objective was the concurrent detection and differentiation of these food-borne pathogens using a multiplex PCR. We therefore designed and optimized a multiplex PCR using three specific PCR primer pairs for the simultaneous detection of these pathogens. The concentration of each of the primer pairs, magnesium chloride concentration, and primer annealing temperature were optimized before verification of the specificity of the primer pairs. The target genes produced amplicons at 429 bp, 300 bp and 620 bp which were shown to be 100% specific to each target bacterium, Salmonella spp., Salmonella Typhi and Salmonella Typhimurium, respectively.
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Affiliation(s)
- Chai Fung Pui
- Center of Excellence for Food Safety Research, Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia
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Liu B, Zhang L, Zhu X, Shi C, Chen J, Liu W, He X, Shi X. PCR identification of Salmonella serogroups based on specific targets obtained by comparative genomics. Int J Food Microbiol 2011; 144:511-8. [DOI: 10.1016/j.ijfoodmicro.2010.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 11/01/2010] [Accepted: 11/07/2010] [Indexed: 11/28/2022]
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Scientific Opinion on monitoring and assessment of the public health risk of “SalmonellaTyphimurium-like” strains. EFSA J 2010. [DOI: 10.2903/j.efsa.2010.1826] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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