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- Occurrence, genetic diversity and antibiotic resistance of Arcobacter sp. in a dairy plantPublication . Ferreira, Susana; Oleastro, Mónica; Domingues, F.C.Aims The aim of this study was to evaluate the occurrence, diversity and resistance to antibiotics of Arcobacter sp. in a dairy plant samples. Methods and Results A total of 75 samples from dairy plant surfaces and materials and several food products collected in different steps of the cheese production process were analysed by culture, under aerobic and microaerobic atmospheric conditions, and by enrichment molecular detection. Isolates were identified and genotyped by ERIC‐PCR, and their susceptibility to nine antibiotics was evaluated by agar dilution. Global prevalence of Arcobacter sp. was 42·7%, where 20 of the 42 food samples analysed were positive for A. butzleri by both culture and molecular detection, one for A. marinus by culture and one for A. cryaerophilus by molecular detection only; 10 of the 30 analysed materials and plant surfaces were positive for A. butzleri. All A. butzleri isolates were resistant to nalidixic acid and showed high resistance rates to ampicillin (56·2%) and cefotaxime (97·9%), being all strains susceptible to gentamicin and erythromycin. Conclusions Contamination of dairy plant environment with A. butzleri and its progression along cheese production process were observed, however, the cheese ripening process may have a relevant role in the reduction of the contamination. Significance and Impact of the Study This study showed the presence of Arcobacter sp. in a dairy plant, displaying its high prevalence and genetic diversity and highlighting its high resistance rates. The data obtained could contribute to further acknowledge the Arcobacter food contamination as a potential health hazard.
- Molecular diagnosis of Arcobacter and Campylobacter in diarrhoeal samples among Portuguese patientsPublication . Ferreira, Susana; Júlio, Cláudia; Queiroz, João; Domingues, F.C.; Oleastro, MónicaThe present study was conducted to investigate the prevalence and diversity of Arcobacter and Campylobacter spp. in 298 stool samples of patients with diarrhoea, collected from 22 Portuguese hospitals, between September and November 2012. Detection of Arcobacter and Campylobacter spp. was performed using molecular-based detection techniques, such as real-time fluorescence resonance energy transfer PCR, species-specific PCR, and sequencing of amplified PCR products. Overall, 1.3% of the samples were positive for Arcobacter butzleri and 0.3% for Arcobacter cryaerophilus. Campylobacter spp. were found in 31.9% of diarrhoeic faeces. Campylobacter jejuni and Campylobacter concisus were the most prevalent species (13.7% and 8.0%, respectively). The prevalence of Arcobacter and Campylobacter spp. was significantly different between children and adults (39.7% versus 22.8%, P = 0.003). We underline the high prevalence of these pathogens in diarrhoeal samples among Portuguese patients, with particular relevance in the paediatric age group.
- A meta-analytic perspective on Arcobacter spp. antibiotic resistancePublication . Ferreira, Susana; Luís, Ângelo; Oleastro, Mónica; Pereira, L.; Domingues, F.C.Objectives: Over the years, an increased prevalence of resistant strains of Arcobacter has been observed, which may be due to Arcobacter exposure to antibiotics used both in animal production and human medicine. A systematic review was performed with the objective of summarising the results of the rates of antimicrobial resistance of Arcobacter isolates. Methods: The systematic review was performed according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analysis) recommendations, followed by meta-analysis. Results: It was observed that the resistance rate ranged between 69.3-99.2% for penicillins and 30.5-97.4% for cephalosporins. The overall percentage of resistance to fluoroquinolones ranged from 4.3% to 14.0%, with the highest resistance percentage observed for levofloxacin. Resistance rates ranged between 10.7-39.8% for macrolides, 1.8-12.9% for aminoglycosides and 0.8-7.1% for tetracyclines. Conclusions: These results show that Arcobacter spp. present resistance to various antibiotics commonly used and advocate further studies of the associated resistance mechanisms.
- Resveratrol against Arcobacter butzleri and Arcobacter cryaerophilus: Activity and effect on cellular functionsPublication . Ferreira, Susana; Silva, Filomena; Queiroz, João; Oleastro, Mónica; Domingues, F.C.The frequent isolation of Arcobacter butzleri and Arcobacter cryaerophilus from food samples makes it imperative to search for potential compounds able to inhibit the development of these bacteria. Taking this into consideration, this study focuses on the antimicrobial activity of resveratrol and its mechanism of action against A. butzleri and A. cryaerophilus. The activity of resveratrol was assessed by a microdilution method and time-kill curves. Resveratrol effect on cellular functions was assessed by flow cytometry evaluating intracellular DNA content and metabolic activity. Ethidium bromide (EtBr) accumulation in the presence of resveratrol was also evaluated, as well as the susceptibility to resveratrol in the presence of phenylalanine-arginine β-naphthylamide (PAβN). Scanning electron microscopy (SEM) was used to further evaluate cell damage caused by resveratrol. Resveratrol presented MIC values of 100 and 50μg/mL to A. butzleri and A. cryaerophilus, respectively. Based on the time-kill curves, resveratrol exhibited bactericidal activity, leading to a ≥3log10CFU/mL reduction of initial inoculums, for A. butzleri exponential phase cells incubated for 6h with 1× MIC or with 2× MIC after 24h for stationary phase cells. For A. cryaerophilus cells in exponential growth phase, 99.9% killing was achieved after 24h incubation with 2× MIC, whereas, for stationary phase cells, bactericidal activity was only detected after incubation with 4× MIC. Incubation with resveratrol led to a decrease in both intracellular DNA content and metabolic activity. An increase in the accumulation of EtBr was observed in the presence of resveratrol, and the efflux pump inhibitor PAβN reduced the MIC of resveratrol. SEM analysis revealed disintegration of A. butzleri cells treated with resveratrol, whereas no morphological alteration was observed for A. cryaerophilus cells. Resveratrol has a good anti-Arcobacter activity, and the results obtained suggest that this compound could act through several different mechanisms in the inhibition of this microorganism. The results encourage the use of this compound for the development of potential strategies to control Arcobacter in food products.
- Insights in the pathogenesis and resistance ofArcobacter: A reviewPublication . Ferreira, Susana; Queiroz, João; Oleastro, Mónica; Domingues, F.C.Arcobacter genus currently comprises 18 recognized species, among which Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii have been associated with human and animal disease. Although these organisms, with special emphasis A. butzleri, are emerging as clinical pathogens, several aspects of their epidemiology and virulence are only starting to be clarified. In vitro human and animal cell culture assays have been used to show that several Arcobacter species can adhere to and invade eukaryotic cells, induce an immune response and produce toxins that damage host cells. In addition, data from genome sequencing highlighted several potential markers that may be helpful candidates for the study and understanding of these mechanisms; however, more work is necessary to clarify the molecular mechanisms involved in Arcobacter virulence. Arcobacter can be considered a relatively robust organism showing to be able to survive in adverse conditions, as the ones imposed by food processing and storage. Moreover, these bacteria have shown increased antibiotic resistance, along with high multidrug resistance. In this review, we seek to update the state-of-the-art concerning Arcobacter distribution, its interaction with the host, the trends of antibiotic resistance, its ability to survive, and finally the use of natural antimicrobials for control of Arcobacter.
- Prevalence of Arcobacter: From farm to retail – A systematic review and meta-analysisPublication . Mateus, Cristiana; Martins, Rodrigo; Luís, Ângelo; Oleastro, Mónica; Domingues, F.C.; Pereira, L.; Ferreira, SusanaArcobacter is a group of bacteria widely distributed in several habitats and throughout the food chain. Considering the pathogenic potential of some species within this group, it is important to understand their distribution along the food chain, as well as the possible routes of transmission. Aiming this, a systematic review and meta-analysis-based method was used to investigate the prevalence of Arcobacter species throughout the food chain, from farm to fork, using the worldwide available data. Database search was performed using related keywords and considering studies up to March 2020. The pooled prevalence of Arcobacter in food chain was 30% (0.300; 95% CI: 0.262–0.342), ranging from 0.5 to 99.4%. The highest prevalence of Arcobacter was observed in Belgium (0.575; 95% CI:0.427–0.710) and the lower in Ireland (0.031; 95% CI:0.022–0.042). Oceania continent (0.409; 95% CI:0.173–0.697) and the countries with high income level (0.342; 95% CI:0.293–0.394) presented the highest prevalence when considering the analysis of subgroups. Arcobacter spp. presented the highest prevalence at the processing stage (0.335; 95% CI:0.270–0.406), when compared with primary and retail stage. Also, data points to the relevance of environmental sources in food contamination. Arcobacter seems to be more frequently found in animal origin products, with the highest prevalence observed for poultry-associated products (0.404; 95% CI: 0.338–0.473), being Arcobacter butzleri the most frequently found species. The results of this meta-analysis highlight the high prevalence and distribution of Arcobacter along the food chain, suggesting a high risk to human health, and the relevance of taking preventive actions in order to reduce the burden of this pathogen in food sector.