Prevalence of Tetracycline-Resistant Campylobacter in Organic Broilers During a Production Cycle

Tetracycline (tet) resistance in Campylobacter isolated from organically raised broilers was investigated in this study. Two hundred forty-five samples from an organic broiler farm were collected weekly from the first week to the end of the production cycle, and they were cultured for thermophilic Campylobacter. Tetracycline resistance of these Campylobacter isolates was identified by the agar dilution method, whereas DNA fingerprinting profiles of tet-susceptible and tet-resistant strains were determined by pulsed-field gel electrophoresis (PFGE). None of the Campylobacter isolates from the third and the fourth week of the production period were resistant to tetracycline, whereas 66.7% of the isolates from the fifth week were resistant to this antibiotic. Although the prevalence of tetracycline resistance reached 100.0% during the sixth and seventh week, less than 34.0% of the isolates from the 10th week were resistant to this antimicrobial agent. In addition, only 13.8% of Campylobacter isolates from the intestinal tracts of these organically raised broilers were resistant to tetracycline. The presence of the tet(O) gene was detected in 98.9% of tet-resistant Campylobacter isolates, and tet-susceptible and tet-resistant Campylobacter strains showed distinct PFGE genotypes. The results suggest that the Campylobacter strains isolated from the early stage of the production were susceptible to tetracycline, but they were subsequently displaced by tet-resistant Campylobacter

Impaired Fitness and Transmission of Macrolide-Resistant Campylobacter jejuni in Its Natural Host

Campylobacter jejuni is a major zoonotic pathogen transmitted to humans via the food chain and is prevalent in chickens, a natural reservoir for this pathogenic organism. Due to the importance of macrolide antibiotics in clinical therapy of human campylobacteriosis, development of macrolide resistance in Campylobacter has become a concern for public health. To facilitate the control of macrolide-resistant Campylobacter, it is necessary to understand if macrolide resistance affects the fitness and transmission of Campylobacter in its natural host. In this study we conducted pairwise competitions and comingling experiments in chickens using clonally related and isogenic C. jejuni strains, which are either susceptible or resistant to erythromycin (Ery). In every competition pair, Ery-resistant (Eryr) Campylobacter was consistently outcompeted by the Ery-susceptible (Erys) strain. In the comingling experiments, Eryr Campylobacter failed to transmit to chickens precolonized by Erys Campylobacter, while isogenic Erys Campylobacter was able to transmit to and establish dominance in chickens precolonized by Eryr Campylobacter. The fitness disadvantage was linked to the resistance-conferring mutations in the 23S rRNA. These findings clearly indicate that acquisition of macrolide resistance impairs the fitness and transmission of Campylobacter in chickens, suggesting that the prevalence of macrolide-resistant C. jejuni will likely decrease in the absence of antibiotic selection pressure

Reducing Risk of Campylobacteriosis from Poultry: A Mini Review

The worldwide annual cost of campylobacteriosis is at least several billion dollars. Risk analysis is being used to reduce the magnitude of the problem and to support regulations and voluntary actions that are successful in that the number of cases of illness is decreasing. The new regulations in the U.S. have resulted in commercial products with fewer Campylobacter. During the last 16 years there has been significant progress in New Zealand because of new regulations that have resulted in reduced numbers of Campylobacter on marketed products. While some progress has been made in reducing cross contamination, it remains an important issue. Food safety education on the general principles of food hygiene and food handling as well as applications of hazard analysis and critical control point (HACCP) principles in food safety management are recommended to address the challenges associated with cross contamination. Economic analysis of campylobacteriosis and the poultry meat industry shows that there are significant benefits of addressing the challenges associated with Campylobacter in poultry products. Freezing has been shown to be an excellent cost-effective method to reduce the number of viable Campylobacter and the number of cases of campylobacteriosis

Distribution and Genetic Profiles of Campylobacter in Commercial Broiler Production from Breeder to Slaughter in Thailand

Poultry and poultry products are commonly considered as the major vehicle of Campylobacter infection in humans worldwide. To reduce the number of human cases, the epidemiology of Campylobacter in poultry must be better understood. Therefore, the objective of the present study was to determine the distribution and genetic relatedness of Campylobacter in the Thai chicken production industry. During June to October 2012, entire broiler production processes (i.e., breeder flock, hatchery, broiler farm and slaughterhouse) of five broiler production chains were investigated chronologically. Representative isolates of C. jejuni from each production stage were characterized by flaA SVR sequencing and multilocus sequence typing (MLST). Amongst 311 selected isolates, 29 flaA SVR alleles and 17 sequence types (STs) were identified. The common clonal complexes (CCs) found in this study were CC-45, CC-353, CC-354 and CC-574. C. jejuni isolated from breeders were distantly related to those isolated from broilers and chicken carcasses, while C. jejuni isolates from the slaughterhouse environment and meat products were similar to those isolated from broiler flocks. Genotypic identification of C. jejuni in slaughterhouses indicated that broilers were the main source of Campylobacter contamination of chicken meat during processing. To effectively reduce Campylobacter in poultry meat products, control and prevention strategies should be aimed at both farm and slaughterhouse levels

Emergence of colistin resistance in extended-spectrum beta lactamase producing Enterobacteriaceae isolated from food animals and its public health implication: A review

Antimicrobial resistance as a result of emergence of extended-spectrum beta lactamase producing Enterobacteriaceae is a major health problem of human and animal that requires an intensive global attention. The production of beta lactamase enzymes remains as one of the major factors contributing to the development of resistance to beta lactams. These enzymes hydrolyze the beta lactam ring of the antibiotic and render it ineffective. Extended-spectrum beta lactamase producing bacteria have the ability to develop resistance to a number of antibiotics including the carbapenem and other third generation cephalosporins. In addition, the recent emergence and dissemination of the colistin resistance determinants mcr-1, mcr-2 and mcr-3 poses a serious threat to colistin as a drug of last resort in human medicine. In this review, we utilized words such as colistin resistance and Escherichia coli, Klebsiella and colistin resistance, colistin resistance and Salmonella as well as detection of mcr-1 genes in Salmonella and E. coli. The extended-spectrum beta lactamase producing bacteria under Enterobacteriaceae that are resistant to colistin possess the ability to be transferred resistant determinants to other susceptible cells at a higher frequency. In this paper, the role of manure from food animals and how air travel contributes to the dissemination of mcr-1 haboring bacteria, resistance determinants and other metabolites that constitute a public health problem was also reviewed. It is concluded that these pathogens have significant consequences to the control of infection and plays key roles in treatment failure with colistin. [J Adv Vet Anim Res 2018; 5(1.000): 1-11

Live-Attenuated Oral Vaccines to Reduce <i>Campylobacter</i> Colonization in Poultry

The control of Campylobacter in poultry at the pre-harvest level is critical to reducing foodborne infections with Campylobacter since the consumption of contaminated poultry is the most frequent cause of human campylobacteriosis. Although poultry vaccination is suggested as useful intervention measures, no Campylobacter vaccines are currently available. To develop live-attenuated oral Campylobacter vaccines, in this study, we evaluated the efficacy of pre-colonization by oxidative stress defense mutants, including knockout mutants of ahpC, katA, and sodB, in preventing Campylobacter jejuni from colonizing poultry. Interestingly, when chickens were pre-colonized with ΔahpC and ΔkatA mutants, rather than the ΔsodB mutant, the level of C. jejuni colonization was significantly reduced within 35 days. Further studies demonstrated when chickens were pre-colonized with the ΔahpC mutant by oral challenge with a high dose (ca., 5 × 108 CFU/bird) and a low dose (ca., 5 × 106 CFU/bird), it twice reduced the level of C. jejuni by 3.9 log10CFU/g feces and 3 log10CFU/g feces after 42 days, respectively, compared to the untreated control. Due to a colonization defect, the ΔahpC mutant was removed from chickens within 42 days. After excretion from the host, moreover, the ΔahpC mutant cannot survive in aerobic environments because of compromised aerotolerance. Our findings suggest that the ahpC mutant has a great potential for on-farm application to control C. jejuni at the pre-harvest level

Impaired Fitness and Transmission of Macrolide-Resistant Campylobacter jejuni in Its Natural Host

Campylobacter jejuni is a major zoonotic pathogen transmitted to humans via the food chain and is prevalent in chickens, a natural reservoir for this pathogenic organism. Due to the importance of macrolide antibiotics in clinical therapy of human campylobacteriosis, development of macrolide resistance in Campylobacter has become a concern for public health. To facilitate the control of macrolide-resistant Campylobacter, it is necessary to understand if macrolide resistance affects the fitness and transmission of Campylobacter in its natural host. In this study we conducted pairwise competitions and comingling experiments in chickens using clonally related and isogenic C. jejuni strains, which are either susceptible or resistant to erythromycin (Ery). In every competition pair, Ery-resistant (Eryr) Campylobacter was consistently outcompeted by the Ery-susceptible (Erys) strain. In the comingling experiments, Eryr Campylobacter failed to transmit to chickens precolonized by Erys Campylobacter, while isogenic Erys Campylobacter was able to transmit to and establish dominance in chickens precolonized by Eryr Campylobacter. The fitness disadvantage was linked to the resistance-conferring mutations in the 23S rRNA. These findings clearly indicate that acquisition of macrolide resistance impairs the fitness and transmission of Campylobacter in chickens, suggesting that the prevalence of macrolide-resistant C. jejuni will likely decrease in the absence of antibiotic selection pressure.This article is published as Luangtongkum, Taradon, Zhangqi Shen, Virginia W. Seng, Orhan Sahin, Byeonghwa Jeon, Peng Liu, and Qijing Zhang. "Impaired fitness and transmission of macrolide-resistant Campylobacter jejuni in its natural host." Antimicrobial agents and chemotherapy 56, no. 3 (2012): 1300-1308. doi: 10.1128/AAC.05516-11. Posted with permission.</p

Identification of a novel membrane transporter mediating resistance to organic arsenic in Campylobacter jejuni

Although bacterial mechanisms involved in the resistance to inorganic arsenic are well understood, the molecular basis for organic arsenic resistance has not been described. Campylobacter jejuni, a major food-borne pathogen causing gastroenteritis in humans, is highly prevalent in poultry and is reportedly resistant to the arsenic compound roxarsone (4-hydroxy-3-nitrobenzenearsonic acid), which has been used as a feed additive in the poultry industry for growth promotion. In this study, we report the identification of a novel membrane transporter (named ArsP) that contributes to organic arsenic resistance in Campylobacter. ArsP is predicted to be a membrane permease containing eight transmembrane helices, distinct from other known arsenic transporters. Analysis of multiple C. jejuni isolates from various animal species revealed that the presence of an intact arsP gene is associated with elevated resistance to roxarsone. In addition, inactivation of arsP in C. jejuni resulted in 4- and 8-fold reductions in the MICs of roxarsone and nitarsone, respectively, compared to that for the wild-type strain. Furthermore, cloning of arsP into a C. jejuni strain lacking a functional arsP gene led to 16- and 64-fold increases in the MICs of roxarsone and nitarsone, respectively. Neither mutation nor overexpression of arsP affected the MICs of inorganic arsenic, including arsenite and arsenate, in Campylobacter. Moreover, acquisition of arsP in NCTC 11168 led to accumulation of less roxarsone than the wild-type strain lacking arsP. Together, these results indicate that ArsP functions as an efflux transporter specific for extrusion of organic arsenic and contributes to the resistance to these compounds in C. jejuni.This article is published as Shen, Zhangqi, Taradon Luangtongkum, Zhiyi Qiang, Byeonghwa Jeon, Liping Wang, and Qijing Zhang. "Identification of a novel membrane transporter mediating resistance to organic arsenic in Campylobacter jejuni." Antimicrobial agents and chemotherapy 58, no. 4 (2014): 2021-2029. doi: 10.1128/AAC.02137-13. Posted with permission.</p

Comparison of Antimicrobial Susceptibility Testing of Campylobacter spp. by the Agar Dilution and the Agar Disk Diffusion Methods

The correlation and the level of agreement between the standardized agar dilution and the agar disk diffusion methods for antimicrobial susceptibility testing of Campylobacter were investigated. A high-level agreement between the two methods was evident for aminoglycosides and fluoroquinolones, while a low-level agreement was observed for other antibiotics.This article is published as Luangtongkum, Taradon, Teresa Y. Morishita, Amna B. El-Tayeb, Aaron J. Ison, and Qijing Zhang. "Comparison of antimicrobial susceptibility testing of Campylobacter spp. by the agar dilution and the agar disk diffusion methods." Journal of clinical microbiology 45, no. 2 (2007): 590-594. doi: 10.1128/JCM.00986-06. Posted with permission.</p

Comparison of Antimicrobial Susceptibility Testing of Campylobacter spp. by the Agar Dilution and the Agar Disk Diffusion Methods

The correlation and the level of agreement between the standardized agar dilution and the agar disk diffusion methods for antimicrobial susceptibility testing of Campylobacter were investigated. A high-level agreement between the two methods was evident for aminoglycosides and fluoroquinolones, while a low-level agreement was observed for other antibiotics