Occurrence, antimicrobial resistance and biofilm formation of Salmonella isolates from a chicken slaughter plant in China

doi:10.1016/j.foodcont.2013.03.030

Food Control

Volume 33, Issue 2, October 2013, Pages 378-384

https://doi.org/10.1016/j.foodcont.2013.03.030 Get rights and content

Highlights

•
The 23 isolates were confirmed for Salmonella and belonged to six serotypes.
•
Resistance to ampicillin (78%, 18/23) was the most common.
•
The 19 isolates showed 13 different multiple antibiotic resistance patterns.
•
Biofilm formation of isolates depended on serotypes and incubation media.
•
No correlation was found between antibiotics resistance and biofilm formation.

Abstract

An investigation was undertaken to determine the occurrence, antibiotic resistance and biofilm formation of Salmonella spp. isolated from a chicken slaughter plant in Anhui, China. A total of 104 samples (52 from chicken carcasses and 52 from processing contact-surfaces) were collected from three processing points in a chicken slaughterhouse. The 23 isolates (22.1%, 23/104) were confirmed for Salmonella and belonged to six different serotypes, including S. Indiana (n = 9), S. Infantis (n = 4), S. Derby (n = 3), S. Heidelberg (n = 2), S. Agona (n = 2) and S. Typhimurium (n = 1), whereas two isolates (n = 2) were non-typable. Significant differences in occurrence were found between post-evisceration, post-chilling and post-grading processing points. A total of 20 (87%, 20/23) isolates were resistant to at least one antibiotic, of which 19 isolates (95%, 19/20) showed 13 multiple antibiotic resistance patterns against 11 different antibiotics. Resistance to ampicillin (78.3%, 18/23) was the most common. The multiple antibiotic resistance (MAR) index varied from 0.27 to 0.91. The Salmonella isolates from the chicken plant and from humans in the same area who were suffering Salmonella infections showed similar antimicrobial resistance patterns, namely resistance to ampicillin, trimethoprim/sulfamethoxazole, gentamicin, chloramphenicol and tretracycline, and abbreviated as “ATsGCT”. Meanwhile, Salmonella isolates exhibited variation in biofilm-forming behavior with regards to the incubation media and serotypes, a relatively high biofilm production was observed for S. Agona incubated in MTLB (meat thawing-loss broth) at 72 h. There was no significant correlation between antimicrobial resistance and biofilm formation of isolates. Our findings provide baseline information on the distribution of Salmonella serovars in this plant, and provide support to the need for improved farming practice and for more prudent use of antimicrobial agents.

Introduction

Salmonella spp. is a globally widespread food-borne pathogen, and its outbreaks are commonly associated with the consumption of contaminated food such as eggs, poultry meat and pork. In EU, Salmonella has become the major cause of food poisoning (EFSA-ECDC, 2012a), while in the USA, contaminated food with Salmonella has resulted in numerous recalls and outbreaks during 2012 that have been addressed by the U.S. Department of Agriculture and Center for Disease Control and Prevention (www.fda.gov/Safety/Recalls).

Recently, much research interest has been drawn to the high occurrence, and antimicrobial resistance of Salmonella in livestock for food products, which may have the potential to transmit to humans through the food chain. Epidemiological studies have implicated foods of animal origin as the major vehicles associated with illnesses caused by Salmonella (Dallal et al., 2010). Despite the occurrence of Salmonella in raw and retail cooked meats have previously been reported (Cook, Odumeru, Lee, & Pollari, 2012; Fearnley, Raupach Lagala, & Cameron, 2011), information on the occurrence of Salmonella at slaughter facilities is limited, even though it is considered as the main source of cross-contamination. Investigation of occurrence of Salmonella in slaughter plants may aid in optimizing HACCP strategy and ensure meat safety in China. Furthermore, investigation of the occurrence and distribution of Salmonella at different slaughter processing stations would be of benefit for the study of the quantitative exposure assessment of Salmonella in chicken meat.

Emergence of multiple resistance of Salmonella isolates and special antimicrobial resistance patterns have raised increasing concern among governments all over the world (Chao, Zhou, Jiao, Qian, & Xu, 2007; EFSA-ECDC, 2012b; Thong & Modarressi, 2011). The link between antimicrobial resistance of Salmonella isolates and outbreaks of human poisoning has already been demonstrated (Folster et al., 2012). In China, human foodborne illnesses have been associated with the antimicrobial resistance of Salmonella isolates (Ran et al., 2011; Yu, Chen, Yu, Li, et al., 2011; Yu, Chen, Yu, Pan, et al., 2011), especially the antibiotic-resistant Salmonella Typhimurium and Salmonella Enteritidis have caused human suffering from serious diarrhoea, the general resistance antibiotics included chloramphenicol, ampicillin, tetracycline, sulfamethoxazole, gentamicin etc., and the common multiple resistance patterns were ACTsT type (resistance to at least ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole, and tetracycline). Therefore, monitoring of Salmonella occurrence and its antimicrobial resistance in the meat-food supply, especially for raw meat in the slaughter plant, is necessary because of the public health implications of a potential spread of antimicrobial resistant Salmonella.

Salmonella can grow as surface-associated aggregates on food contact-surfaces and equipment (Chia, Goulter, McMeekin, Dykes, & Fegan, 2009), commonly referred to as biofilms. The cells in biofilms are potential sources of contamination of food products. Biofilms may play a crucial role in the survival of Salmonella under unfavorable environmental conditions, such as in animal slaughterhouses and processing plants. To date, relatively little research has examined the ability of biofilm formation of Salmonella isolated from slaughter plants under the conditions commonly encountered. Moreover, the relationship between antimicrobial resistance and the ability of Salmonella isolates to form biofilms is unknown. The present study was therefore carried out to (i) determine the occurrence and distribution of Salmonella at processing points at a chicken slaughterhouse, (ii) identify the antimicrobial resistance patterns and the ability of biofilm formation of Salmonella isolates, and (iii) evaluate the correlation between number of isolates resistant to antibiotics and biofilm formation of Salmonella isolates.

Section snippets

Sample collection

A total of 104 samples, collected from chicken carcass surfaces (n = 52) and processing contact-surfaces (n = 52), were obtained from three processing points (post-evisceration point n = 40, post-chilling point n = 32 and post-grading point n = 32) at a chicken slaughter plant in Anhui Province (China), during September 2011 (Fig. 1). The samples were collected on each Wednesday of three consecutive weeks (35, 35 and 34 samples at each time, respectively). At each collection point, the number

The occurrence of Salmonella spp.

Of the samples tested, 22% (23/104) were positive for Salmonella. In addition to identification of the isolates by biochemical characterization, we further identified them by detecting invA and hilA genes, which are commonly used as the PCR diagnostic targets for Salmonella in the food industry and research fields (Joshi et al., 2009; McCabe, Burgess, Walsh, et al., 2011). The results (Table 1) indicated that all the 23 isolates were positive for detection of invA and hilA genes. These isolates

Discussion

Poultry foods are generally considered to be at a higher risk for Salmonella contamination than other foods. In 2012, several outbreaks of Salmonella have been associated with poultry meat and products (www.cdc.gov/salmonella/outbreaks.html). During chicken slaughter, Salmonella from the gastro-intestinal tract of chickens carrying pathogens can contaminate the carcasses and the processing line (Rostagno, Wesley, Trampel, & Hurd, 2006). Although efforts at controlling Salmonella have

Acknowledgments

We are very grateful to Prof. Ron Tume from CSIRO, Animal, Food and Health Sciences, Australia for his valuable advice and for assistance with language. This study was supported by China Agriculture Research System (CARS-42) funded by the China Ministry of Agriculture.

References (43)

F. Adzitey et al.
Prevalence and antibiotic resistance of Salmonella serovars in ducks, duck rearing and processing environments in Penang, Malaysia
Food Research International
(2012)
P. Antunes et al.
Incidence of Salmonella from poultry products and their susceptibility to antimicrobial agents
International Journal of Food Microbiology
(2003)
C.X. Chen et al.
Characteristics of Escherichia coli biofilm production, genetic typing, drug resistance pattern and gene expression under aminoglycoside pressures
Environmental Toxicology and Pharmacology
(2010)
T.W.R. Chia et al.
Attachment of different Salmonella serovars to materials commonly used in a poultry processing plant
Food Microbiology
(2009)
A. Cook et al.
Campylobacter, Salmonella, Listeria monocytogenes, Verotoxigenic Escherichia coil, and Escherichia coil occurrence, enumeration, and subtypes on retail chicken breasts with and without skin
Journal of Food Protection
(2012)
M.M.S. Dallal et al.
Prevalence and antimicrobial resistance profiles of Salmonella serotypes, Campylobacter and Yersinia spp. isolated from retail chicken and beef, Tehran, Iran
Food Control
(2010)
P. Depoorter et al.
Assessment of human exposure to 3rd generation cephalosporin resistant E. coli (CREC) through consumption of broiler meat in Belgium
International Journal of Food Microbiology
(2012)
M. Díez-García et al.
Influence of serotype on the growth kinetics and the ability to form biofilms of Salmonella isolates from poultry
Food Microbiology
(2012)
E. Fearnley et al.
Salmonella in chicken meat, eggs and humans, Adelaide, South Australia, 2008
International Journal of Food Microbiology
(2011)
J. Fricks-Lima et al.
Differences in biofilm formation and antimicrobial resistance of Pseudomonas aeruginosa isolated from air ways of mechanically ventilated patients and cysticfibrosis patients
International Journal of Antimicrobial Agents
(2011)

C.S. Jacobsen et al.

Quantification of mRNA in Salmonella sp. seeded soil and chicken manure using magnetic capture hybridization RT-PCR

Journal of Microbiological Methods

(2007)

R. Joshi et al.

Selection, characterization, and application of DNA aptamers for the capture and detection of Salmonella enterica serovars

Molecular and Cellular Probes

(2009)

S. Kim et al.

Molecular characterization of biofilm formation and attachment of Salmonella enterica serovar Typhimurium DT104 on food contact surfaces

Journal of Food Protection

(2009)

T. Lei et al.

Antimicrobial resistance in Escherichia coli isolates from food animals, animal food products and companion animals in China

Veterinary Microbiology

(2010)

E.M. McCabe et al.

Development and evaluation of DNA and RNA real-time assays for food analysis using the hilA gene of Salmonella enterica subspecies enterica

Food Microbiology

(2011)

E.M. McCabe et al.

Validation of DNA and RNA real-time assays for food analysis using the hilA gene of Salmonella enterica serovars

Journal of Microbiological Methods

(2011)

R. Marrero-Ortiz et al.

Genetic characterization of antimicrobial resistance in Salmonella enterica serovars isolated from dairy cattle in Wisconsin

Food Research International

(2012)

J. Patel et al.

Differences in attachment of Salmonella enterica serovars to cabbage and lettuce leaves

International Journal of Food Microbiology

(2010)

M.H. Rostagno et al.

Salmonella prevalence in market-age turkeys on farm and at slaughter

Poultry Science

(2006)

P. Saa et al.

Effects of mussel processing soils on the adherence of Listeria monocytogenes to polypropylene and stainless Steel

Journal of Food Protection

(2009)

K. Silagyi et al.

Production of biofilm and quorum sensing by Escherichia coli O157:H7 and its transfer from contact surfaces to meat, poultry, ready-to-eat deli, and produce products

Food Microbiology

(2009)

Cited by (91)

Effects of antibiotic-induced resistance on the growth, survival ability and virulence of Salmonella enterica
2023, Food Microbiology
Salmonella enterica is an important foodborne pathogen that constitutes a major health hazard. The emergence and aggravation of antibiotic-resistant Salmonella has drawn attention widely around the world. Conducting a risk assessment of antibiotic-resistant foodborne pathogens throughout the food chain is a pressing requirement for ensuring food safety. The growth, survival capability, and virulence of antibiotic-resistant Salmonella represent crucial biological characteristics that play an important role in microbial risk assessment. In this study, eight antibiotic-sensitive S. enterica strains were induced by Ampicillin (Amp) and Ciprofloxacin (CIP), respectively, and AMP-resistant and CIP-resistant mutants were obtained. The growth characteristics under different temperatures (25, 30, 35 °C), viability after exposure to heat (55, 57.5, 60 °C) and acid (HCl, pH = 3.0), the virulence potential (adhesion and invasion to Caco-2 cells, biofilm formation and motility) and the lethality in a model species (Galleria mellonella) were evaluated and compared for S. enterica strains before and after antibiotic exposure. The induction by AMP and CIP are likely to promote cross-antibiotic resistance to their antibiotic classes, β-lactams and quinolones, as well as some compound antibiotics. It was observed that generally the antibiotic-induction-resistant strains showed decreased growth ability and lower heat resistance, although the differences were not significant at all the conditions tested. The AMP-resistant strains were significantly less acid resistance than the sensitive and the CIP-resistant ones, while exhibiting increased biofilm formation ability. In general, the antibiotic-induced resistance did not significantly affect the motility, adherence, or invasion ability of Caco-2 cells. However, CIP-resistant strains displayed lower lethality in G. mellonella infection, whereas AMP-resistant strains did not, and even two strains improved lethality. The study of the biological characteristics of antibiotic-resistant S. enterica is essential in better understanding the microbial risks to both the food chain and human health, thereby facilitating a more accurate risk assessment.
Comparison of sanitization efficacy of sodium hypochlorite and peroxyacetic acid used as disinfectants in poultry food processing plants
2023, Food Control
This study, we aimed to evaluate the in situ disinfection efficacy of peroxyacetic acid (PAA) and sodium hypochlorite (SH) against pathogens (Escherichia coli, Staphylococcus aureus, Salmonella Typhimurium, and Listeria monocytogenes in suspension, and food contact surfaces of steel and utensil.
In the clean and contaminated conditions, as the concentrations of PAA and SH increased (0–200 ppm) for 1 min and 5 min, the viable count of pathogenic bacteria reduced. In particular, more than 7 log cycle reductions in the pathogen population were observed using 200 ppm PAA and 100 ppm SH, except for S. aureus in the latter.
Four pathogenic bacteria spiked (5–6 log/mL), each on the surface of the main processing machine (stainless steel, n = 36), displayed over 6 log reduction after treatment with 100 ppm PAA for 5 min, which was more effective than SH treatment at similar conditions.
To compare the sterilization effect, swab sampling (n = 27) before and after working with poultry on cutting boards, knives, and worktable was performed. E. coli, coliforms, and total bacteria were considerably reduced using 100 ppm of both PAA and SH.
After five different treatment concentrations (0–200 ppm) at 4 °C for seven days, chicken breasts treated with 200 ppm PAA exhibited a significant (P < 0.05) inhibitory effect on the total bacteria (1.29 log₁₀) and coliform group organisms (1.10 log₁₀) populations compared with the control chicken breast. Overall, PAA treatment had an effective antimicrobial activity in fresh poultry samples. The microbiological safety of poultry is an important public health concern worldwide, thus, the use of PAA as a disinfectant will greatly contribute to the improvement of poultry microbial safety.
Bacteriological quality assessment of poultry chicken meat and meat contact surfaces for the presence of targeted bacteria and determination of antibiotic resistance of Salmonella spp. in Pakistan
2023, Food Control
During the slaughtering process, the meat product cross-contaminates with the surrounding contact surfaces. This study aimed to assess the level of microbial contamination of poultry chicken meat and contact surfaces at poultry slaughterhouses in the Hyderabad and Jamshoro districts of Pakistan. A total of 38 slaughter shops were selected, and from each shop, three types of samples were collected. All the samples were assessed for the presence of three microbes, Salmonella, Shigella, and E. coli by using some culture-based techniques, and for Salmonella, antibiotic resistance was also determined. Results revealed that Shigella was present in 86.8% of knives, 94.7% of chopping board and 97.3% of meat samples. While, the E. coli was present in 86.8% of knife, 97.3% of chopping board, and 97.3% of meat samples. Salmonella was detected in 97.3% of knives, 92% of chopping boards, and 97.3% of meat samples. All the isolates of Salmonella exhibited resistance to one or more antibiotics. Resistance to ampicillin, gentamicin, cefotaxime, erythromycin, neomycin, streptomycin, and sulphamethoxazole were evident in 91.7%, 25.6%, 32.1%, 40.3%, 33.9%, 34.8%, and 52.2% respectively. However, only 6.4% of isolates showed resistance to azithromycin (6.4%), and none of them showed resistance to ceftazidime. Moreover, 61.4% (67/109) of isolates were multiple drug-resistance (MDR). A high prevalence of Salmonella, Shigella, and E. coli in meat and on contact surfaces can be considered a major risk for human health. It is vital to continue developing strategies to limit the danger of foodborne diseases in slaughtering facilities.
Transcriptome sequencing reveals the difference in the expression of biofilm and planktonic cells between two strains of Salmonella Typhimurium
2022, Biofilm
Salmonela enterica serovar Typhimurium (S. Typhimurium) is a food-borne pathogen that can form biofilms to increase its resistance to the external environment. Through the detection of biofilm of several S. Typhimurium strains in this study, strain CDC3 with strong biofilm forming capacity and strain CVCC3384 with weak biofilm forming capacity were identified. The genes expressed in planktonic and biofilm cells of two S. Typhimurium strains were analysed by transcriptome sequencing. Results showed that the genes related to the signal transduction pathway were upregulated and genes related to motility were downregulated in strain CDC3. By comparing biofilms and planktonic cells of the two strains, we found that CDC3 regulates biofilm formation mainly through the two-component system kdpABC, while strain CVCC3384 does so mainly through motility and quorum sensing. This study revealed regulation mechanism of biofilms formation between different biofilm forming capacity strains, and provided a theoretical basis for subsequent research.
A systematic review and Bayesian meta-analysis about Salmonella spp. prevalence on raw chicken meat
2022, Microbial Risk Analysis
Salmonellosis involving chicken meat is one of the most frequent foodborne diseases registered worldwide. Many studies report the prevalence of Salmonella spp. on chicken meat; however, data are limited or variable. To perform stochastic Quantitative Microbial Risk Analysis, it is essential to input reliable data to estimate the risks, and the Bayesian meta-analysis model allows incorporating the uncertainty of the data into parameters which increases the robustness of the model. In this manuscript, we conduct a systematic review and a logit-normal hierarchical Bayesian meta-analysis model to assess the posterior distribution of Salmonella spp. prevalence of raw chicken meat. The posterior distribution of Salmonella spp. was reported according to carcass processing (whole carcass or cuts); cold status (fresh meat or frozen); place of sampling (retail or slaughterhouse), and geographical region (Brazil, Latin America, North America, Africa, Asia, and Europe). To implement the posterior distribution as uncertainty in stochastic a model, parameters were obtained by linear combination of the posterior distributions of the model. The percentual of variation regarding the heterogeneity between studies is 33.93%. Carcass processing and cold status do not influence Salmonella spp. prevalence. Raw chicken meat collected at slaughterhouses had a 4% higher chance of being positive for Salmonella spp. than those taken at retail. However, this small difference seems to be of minor relevance given the large 95% credible interval around the parameter. The posterior distribution shows lower Salmonella spp. prevalence for Latin America, Brazil, Africa, Europe when compared to North America and Asia. In the sensitivity analysis, the parameters $β_{c o l d}$ , $β_{s a m p l e}$ , and $β_{p r o c e s s i n g}$ were weakly influenced by the priors, however, the relevance of the priors was more evident for the geographic region related parameters. Salmonella Enteritidis was the most widespread serovar identified and only three studies verified the concentration of Salmonella spp. but we were not able to conduct a meta-analysis because the studies omitted the standard deviation.
Antibiofilm effects of quercetin against Salmonella enterica biofilm formation and virulence, stress response, and quorum-sensing gene expression
2022, Food Control
Salmonellosis is a prevalent food poisoning disease caused by Salmonella spp. that affects millions of people throughout the world. Contamination of chicken meat and processing equipment with Salmonella is a major issue in the food industry. Therefore, it is necessary to study not only food but also food contact surfaces [plastic (PLA) and rubber gloves (RG)] that can cause cross-contamination during processing. The inhibitory activities of quercetin, an antioxidant and antibacterial compound, were tested against S. Typhimurium and S. Enteritidis on PLA, RG, and chicken skin during biofilm. When quercetin (0–125 μg/mL) was supplemented, the inhibitory effect was 1.50–2.61 log CFU/cm² (125; 1/2, 62.5; 1/4, and 31.25 μg/mL; 1/8 MIC). Furthermore, the initial biofilm formation rate of both bacteria was greater on the chicken skin surface than on the food contact surfaces. The inhibitory impact was visually observed using field-emission scanning electron microscopy and confocal laser scanning microscopy. The swimming and swarming motility was also found to be inhibited from 1/8 MIC. As determined by qRT-PCR, quercetin downregulated the expression levels of virulence (avrA, and hilA), stress response (rpoS), and quorum-sensing (luxS) genes. Our findings suggest that plant-derived quercetin is a possible antibiofilm agent against Salmonella spp. biofilm formation, as well as biofilm caused by other bacteria.

View all citing articles on Scopus

View full text

Occurrence, antimicrobial resistance and biofilm formation of Salmonella isolates from a chicken slaughter plant in China

Highlights

Abstract

Introduction

Section snippets

Sample collection

The occurrence of Salmonella spp.

Discussion

Acknowledgments

Food Research International

International Journal of Food Microbiology

Environmental Toxicology and Pharmacology

Food Microbiology

Journal of Food Protection

Food Control

International Journal of Food Microbiology

Food Microbiology

International Journal of Food Microbiology

International Journal of Antimicrobial Agents

Journal of Microbiological Methods

Molecular and Cellular Probes

Journal of Food Protection

Veterinary Microbiology

Food Microbiology

Journal of Microbiological Methods

Food Research International

International Journal of Food Microbiology

Poultry Science

Journal of Food Protection

Food Microbiology