Occurrence and Antimicrobial Resistance of Arcobacter spp. Recovered from Aquatic Environments

Arcobacter spp. are emerging waterborne and foodborne zoonotic pathogens responsible for gastroenteritis in humans. In this work, we evaluated the occurrence and the antimicrobial resistance profile of Arcobacter isolates recovered from different aquatic sources. Besides, we searched for Arcobacter spp. in seaweeds and the corresponding seawater samples. Bacteriological and molecular methods applied to 100 samples led to the isolation of 28 Arcobacter isolates from 27 samples. The highest prevalence was detected in rivers followed by artificial ponds, streams, well waters, and spring waters. Seaweeds contained a higher percentage of Arcobacter than the corresponding seawater samples. The isolates were identified as Arcobacter butzleri (96.4%) and Arcobacter cryaerophilus (3.6%). All the isolates showed a multi-drug resistance profile, being resistant to at least three different classes of antibiotics. Molecular analysis of genetic determinants responsible for tetracycline resistance in nine randomly chosen isolates revealed the presence of tetO and/or tetW. This work confirms the occurrence and the continuous emergence of antibiotic-resistant Arcobacter strains in environmental samples; also, the presence of quinolone-resistant Arcobacter spp. in aquatic sources used for water supply and irrigation represents a potential risk for human health.

Characterization of Arcobacter spp. Isolated from human diarrheal, non-diarrheal and food samples in Thailand

Arcobacter butzleri is an emerging zoonotic food-borne and water-borne pathogen that can cause diarrhea in humans. The global prevalence of A. butzleri infection is underestimated, and little is known about their phenotypic and genotypic characterization. The aim of this study was to determine antimicrobial susceptibility (AST) profiles, detect related virulence genes, and classify sequence type (ST) of A. butzleri isolates obtained from human stool and food samples. A total of 84 A. butzleri isolates were obtained from human diarrheal (n = 25), non-diarrheal (n = 24) stool, and food (n = 35) samples in Thailand. They were evaluated for phenotypic identification by conventional microbiological procedures and AST by Kirby-Bauer disc diffusion method as well as virulence genes detection. Representative isolates from each origin were selected based on the presence of virulence genes and AST profiles to analyze genetic diversity by multilocus sequence typing (MLST). All isolates showed resistance to nalidixic acid 40.5% (34/84), ciprofloxacin 11.9% (10/84), azithromycin 8.3% (7/84), and erythromycin 3.6% (3/84). Regarding the ten virulence genes detected, cj1349, mviN and pldA had the highest prevalence 100% (84/84), followed by tlyA 98.8% (83/84), cadF 97.6% (82/84), ciaB 71.4% (60/84), hecA and hecB 22.6% (19/84), iroE 15.5% (13/84) and irgA 10.7% (9/84), respectively. Three virulence genes were present among A. butzleri isolates of human diarrheal stool and food samples, with a significant difference observed among isolates; hecB [36% (9/25) and 8.6% (3/35)], hecA [36% (9/25) and 5.7% (2/35)], and irgA [24% (6/25) and 2.9% (1/35)] (p < 0.05), respectively. The hecA and hecB virulence genes functions are related to the mechanism of hemolysis, while irgA supports a bacterial nutritional requirement. MLST analysis of 26 A. butzleri isolates revealed that 16 novel STs exhibited high genetic diversity. The results of this study is useful for understanding potentially pathogenic and antimicrobial-resistant A. butzleri in Thailand. The pathogenic virulence markers hecB, hecA, and irgA have the potential to be developed for rapid diagnostic detection in human diarrheal stool. No significant relationships among STs and sources of origin were observed. Little is known about A. butzleri, the mechanism of action of these virulence genes, is a topic that needs further investigation.

Optimization of the In Vitro Bactericidal Effect of a Mixture of Chlorine and Sodium Gallate against Campylobacter spp. and Arcobacter butzleri

ABSTRACT Campylobacter spp. and Arcobacter butzleri are foodborne pathogens associated with the consumption of contaminated raw chicken meat. At the industry level, the combination of new and common antimicrobials could be used as a strategy to control the presence of pathogens in chicken carcasses. The objective of this study was to determine the bacteriostatic and bactericidal effects of a mixture of chlorine (Cl) and sodium gallate (SG) on a mixture of two Campylobacter species (Campylobacter jejuni and Campylobacter coli) and A. butzleri. Using a central composite experimental design, it was established that the optimum inhibitory SG-Cl concentration for Campylobacter spp. was 44 to 45 ppm. After 15 h of incubation, Campylobacter species growth was reduced by 37.5% and the effect of Cl was potentiated by SG at concentrations above 45 ppm. In the case of A. butzleri, optimum levels of 28 and 41 ppm were observed for SG and Cl, respectively; no synergism was reported, as this bacterium was more sensitive to lower Cl concentrations than Campylobacter. After a 20-min pretreatment with peracetic acid (50 ppm), the optimum condition to achieve a &gt;1.0-Log CFU/mL reduction of Campylobacter spp. was exposure to 177 ppm of Cl and 44 ppm of SG for 56 min. As A. butzleri showed lower resistance to the bacteriostatic effect of the Cl-SG combination, it was assumed that optimum bactericidal conditions for Campylobacter spp. were effective to control the former; this was confirmed with subsequent validation of the model. The SG-Cl combination has bactericidal properties against Campylobacter and A. butzleri, and it may be a useful strategy to improve sanitary practices applied in the poultry industry. HIGHLIGHTS

The incidence and antimicrobial resistance of Arcobacter species in animal and poultry meat samples at slaughterhouses in Iran

Background and Objectives: Arcobacter species are food-borne and zoonotic enteropathogens. Defined breakpoints for the investigation of antimicrobial resistance of Arcobacter are missing. Materials and Methods: The study was performed to investigate the incidence and antimicrobial resistance of Arcobacter species in animals and poultry meat samples procured from slaughterhouses in Iran. To investigate the prevalence of antimi- crobial resistance, samples were collected from cattle (n=100), sheep (n=100), goat (n=100), broiler chicken (n=100), turkey (n=100) and quail (n=100). Arcobacter isolates of meat samples were isolated, investigated by PCR method and antibiotic resistance was also investigated. The susceptibility was assessed by Kirby-Bauer disc diffusion. Results: The results showed that 52 samples (8.66%) were positive for Arcobacter spp. The most prevalence were observed in broiler chickens (26%, n=26 samples), quail (13%, n=13 samples), turkey (8%, n=8), cattle (3%, n=3), sheep (1%, n=1) and goat (1%, n=1). Arcobacter butzleri had highest prevalence among Arcobacter species. All the isolates showed sensitiv- ity to gentamicin, streptomycin and tetracycline. Conclusion: Poultry meat is a potential source of infection with Arcobacter that must be considered in slaughterhouses in Iran. Arcobacter species showed sensitivity for a broad spectrum of antibiotics that can be used during infection with Arco- bacter species.

Isolation of Arcobacter spp. and identification of isolates by multiplex PCR from various domestic poultry and wild avian species

Purpose The purpose of the present study was to determine the extent and seasonal prevalence of Arcobacter spp. in domestic poultry and wild birds in the Kars region of Turkey using multiplex polymerase chain reaction (m-PCR). Methods In this study, 1570 samples were collected from domestic poultry and wild avian species. The numbers of collected samples were as follows: 182 fecal samples from chickens, geese, and turkeys from family farms in the Kars region in Turkey; 1089 cloacal swab samples from chickens, geese, ducks, turkeys, and quails from family farms in this region; and 299 fecal samples from wild pigeons, crows, and owls in the same region. Results Arcobacter spp. were isolated from 17.43%, 35.77%, 3.63%, 6.87%, and 3.33% of the cloacal swab samples obtained from geese, ducks, chickens, turkeys, and quails, respectively. In the stool samples, Arcobacter spp. were isolated from 9.62%, 13.33%, and 4% of chicken, goose, and turkey samples, respectively. In wild birds, the isolation rates of Arcobacter spp. were 6.6%, 12.15%, and 0% in pigeons, crows, and owls, respectively. Using m-PCR, among 171 Arcobacter spp. isolates obtained from poultry and wild birds, 67, 78, 24, and 2 were identified as Arcobacter cryaerophilus, Arcobacter butzleri, Arcobacter skirrowii, and Arcobacter cibarius, respectively. Conclusions Both poultry and wild avian species exhibited variable rates of Arcobacter species positivity. The presence of Arcobacter spp. in the digestive tracts of healthy poultry and wild birds may serve as a potential reservoir for the dissemination of these microbes in the environment and their transmission to other animals and humans.