Biofilm formation of Campylobacter strains isolated from raw chickens and its reduction with DNase I treatment

Campylobacter is a well-known bacterial agent that causes foodborne gastroenteritis. Its biofilm-forming ability is known to be important for its survival in harsh conditions. Poultry is a main reservoir of Campylobacter. In this study, we evaluated the biofilm-forming ability, motility, and antibiotic susceptibility of Campylobacter strains isolated from commercially purchased chickens of various sources in South Korea. From 37 (30%) out of 124 chickens, a total of 78 Campylobacter isolates were obtained, and the ability of these strains to form biofilms was studied on polystyrene surfaces. We identified seven biofilm-forming strains of Campylobacter jejuni and Campylobacter coli, respectively, out of 60 C. jejuni and 18 C. coli strains. Our study demonstrated that motility is inconsistent with biofilm-forming ability, suggesting that motility is not a single factor affecting biofilm formation of Campylobacter. Moreover, there was no clear relationship between antibiotic resistance and biofilm-forming ability. DNase I treatment significantly inhibited the biofilm formation or degraded the mature biofilms of 3 C. coli and 1 C. jejuni biofilm-forming strains (p < 0.05). It suggests that extracellular DNA plays a significant role in the biofilm formation of these strains. Collectively, our study demonstrated that biofilm-forming ability is not strongly correlated with motility and antibiotic resistance in Campylobacter and that extracellular DNA is required for biofilm formation of the isolated Campylobacter strains. It also suggests that DNase I is a potential method for the control of Campylobacter biofilms.     

Prevalence and antimicrobial resistance of Campylobacter species isolated from the avian eggs

Campylobacter is one of the most important food borne pathogens that cause bacterial gastroenteritis worldwide. The most commonly isolated species in humans are Campylobacter jejuni (C. jejuni) and Campylobacter coli. The emergence of antimicrobial resistance in Campylobacter spp. has been a growing public health concern globally. Information about antimicrobial resistance of Campylobacter at different levels of production is important for the development of control strategies for this pathogen. This study was conducted to determine the prevalence and antimicrobial resistance of Campylobacter spp. isolated from different eggs from different avian species in Iran. A total of 440 egg samples were collected from different avian and analyzed for the presence of Campylobacter spp. in eggshell and eggs content under sterile conditions using Campylobacter selective agar base and the species were identified by biochemical tests. The suspected colonies were subjected to PCR assay for final confirmation as Campylobacter spp., and identification of C. jejuni or Campylobacter coli. Antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method using Mueller Hinton agar. Campylobacters were detected in a total of 7 out of 100 (7%) eggshell of chicken samples and in 3 out of 60 (5%) eggshell of duck samples. In addition, Campylobacter spp. were also detected in 3.3%, 2.5%, 4.2%, 5% and 3.8 of the eggshell of goose, ostrich, partridge, quail and turkey samples, respectively. The overall prevalence rate of Campylobacter species from different avian eggs was found to be 7.7% (34/440). Among different avian egg samples, Campylobacter jejuni was more frequently isolated 28 (n = 28, 6.3%) than C. coli 6 (n = 6, 1.3%). In addition, the prevalence of C. jejuni was highest in summer and lowest in autumn. In this study Campylobacter spp. showed significant difference in resistance pattern with tetracycline and ciprofloxacin but gentamicin resistance was not found in both C. coli and C. jejuni isolates. Therefore, gentamicin is safe and effective drugs for the treatment of human campylobacteriosis if avian egg is considered as the source of infection.     

Rutin inhibits mono and multi-species biofilm formation by foodborne drug resistant Escherichia coli and Staphylococcus aureus

Considering the role of biofilm in food spoilage and the food industry, inhibition of biofilm formation by natural agents is expected to be safe and could also enhance the efficacy of other antimicrobial strategies for controlling microbial food spoilage. Plant flavonoids are known for their diverse biological activity including antimicrobial. Therefore, rutin was investigated for its biofilm inhibitory activity at sub-minimum inhibitory concentrations (sub-MICs) values against common foodborne pathogens (Escherichia coli and Staphylococcus aureus). Minimum inhibitory concentrations (MIC) ranged from 400 to 1600 μg/ml against the selected strains. Sub-MICs (1/16 × MIC to 1/2 × MIC) were used to assess the inhibition of biofilm formed by E. coli and S. aureus in microtitre plate assay. Mono strain biofilm formation by Escherichia coli and Staphylococcus aureus was greatly reduced by rutin at their respective 1/2 × MIC. For multi-species (E. coli: and S. aureus) biofilm formation, the reduction in biofilm production was concentration dependent. No significant bacteria mass reduction was recorded for any sub-MIC. SEM images of biofilm inhibition on steel chips confirmed the reduction in number of microcolonies. Exopolysaccharide production responsible for adherence and maturation of biofilms was also significantly (p ≤ 0.05) reduced at respective concentrations of rutin in tested strains. To the best of our knowledge, this is the first study describing the effect of flavonoid, rutin on multi-species biofilms consisting of S. aureus and E. coli. Findings of the study indicate a potential application of rutin in the prevention of biofilm on industrial equipment and food contact surfaces and prevent food contamination and spoilage.     

Identification and antimicrobial resistance of Campylobacter species isolated from poultry meat in Khorasan province,Iran

Campylobacter is the main bacterial cause of acute gastroenteritis in humans. Campylobacter jejuni and Campylobacter coli are the most frequent Campylobacter species isolated from patients with diarrhea. Undercooked poultry meat is one of the main sources of human infection. Contamination of poultry carcasses by Campylobacter during processing occurs directly via intestinal contents or indirectly from bird to bird, via equipment and water. The objective of this study was to determine the prevalence and antimicrobial resistance patterns of Campylobacter spp. isolated from raw poultry meat in Mashhad, Iran. From May 2012 to July 2012, 300 poultry meat samples including chicken (150), turkey (70), partridge (50), and quail (30) were randomly purchased from retail outlets. Using cultural method and a PCR assay 49.7% of poultry meat samples were contaminated with Campylobacter spp. Campylobacter spp. were significantly (P < 0.05) more prevalent in chicken meat (59.3%), followed by partridge (48%), quail (40%), and turkey (34.3%) meat. The most prevalent Campylobacter spp. isolated was C. jejuni (80.8%); the remaining isolates were C. coli (19.3%). Overall, 96.6% Campylobacter isolates were resistant to one or more antimicrobial agent. Resistance to ciprofloxacin was the most common finding (81.9%), followed by resistance to nalidixic acid (73.2%) and tetracycline (67.8%). In conclusion, the results of this study showed the importance of chicken, quail, partridge, and turkey meat as potential sources of Campylobacter spp. infection in people.     

Polyphenolic extract from Rosa rugosa tea inhibits bacterial quorum sensing and biofilm formation

Quorum sensing (QS) is an intercellular signaling and gene regulatory mechanism, which is implicated in bacterial pathogenicity and food spoilage. Therefore, blocking bacterial QS system may prevent QS-controlled phenotypes responsible for food spoilage. In the present study, we aimed to investigate the anti-biofilm and quorum sensing inhibitory potentials of Rosa rugosa tea polyphenol (RTP) extract, which is rich in polyphenols (87.52%) and flavonoids (61.03%). The RTP specifically inhibited QS-controlled violacein production in Chromobacterium violaceum 026 with 87.56% reduction without significantly affecting its growth. Moreover, RTP exhibited inhibition in swarming motility (84.90% and 78.03%) and biofilm formation (67.02% and 72.90%) of Escherichia coli K-12 and Pseudomonas aeruginosa PAO1 in a concentration-dependent manner, respectively. These findings strongly suggest that RTP potentially could be developed as a new QS inhibitor and/or anti-biofilm agent to enhance the shelf life and increase food safety.     

Stilbene phytoallexins inclusion complexes: A natural-based strategy to control foodborne pathogen Campylobacter

Due to the highly epidemic character of Campylobacter infections and to the increased antibiotic resistance of these microorganisms, new approaches to control them are highly demanded. In this work, we investigated the anti-Campylobacter activity and mode of action of stilbenes encapsulated in cyclodextrins. Results showed that pterostilbene and pinosylvin and their inclusion complexes (ICs) had antimicrobial activity against Campylobacter jejuni and Campylobacter coli. Furthermore, pinosylvin ICs had a bactericidal activity against both Campylobacter species at 37 °C and even at 4 or 20 °C. This bactericidal action is due to membrane damage, resulting in the impairment of several cellular functions such as membrane polarization, permeability and efflux activity. This is the first study describing the antimicrobial activity of stilbenes and their inclusion complexes against Campylobacter spp. and the results obtained encourage the use of pinosylvin as a preservative for the effective control of Campylobacter in foods.     

Trends in the occurrence and characteristics of Campylobacter jejuni and Campylobacter coli isolates from poultry meat in Northern Poland

The aim of this study was to investigate the occurrence of Campylobacter spp. in poultry meat available in retail stores in the northern part of Poland during a five-year period (2009–2013). A total of 742 poultry meat samples were collected from butcher shops and supermarkets including the following types of samples: chicken breast filets (n = 133), turkey breast filets (n = 112), chicken wings (n = 135), chicken leg quarters (n = 128), chicken drumsticks (n = 115), and chicken giblets (n = 119).The results indicated that 41.6% of the samples were positive for Campylobacter spp., and Campylobacter jejuni was predominant in this study. The prevalence of Campylobacter spp. changed during the study period, decreasing from 60.2% in 2009 to 32% in 2013.The characterization of the isolates revealed a high prevalence of Campylobacter virulence genes. All Campylobacter spp. isolates from poultry meat contained the cadF gene, which is responsible for adherence. The flaA gene, which is involved in motility, was present in all C. jejuni and Campylobacter coli strains. The cdtB, which is associated with toxin production, was present in 93.3% of C. jejuni strains and 89.6% of C. coli strains. The iam gene, which is associated with the invasiveness of Campylobacter spp., was predominant in C. coli strains (95.6%) compared to C. jejuni strains (84.5%).Resistance to four antimicrobials was also examined. The prevalence of resistance among the obtained C. jejuni and C. coli isolates was as follows: ciprofloxacin (62.8% and 72.2%, respectively), tetracycline (42.3% and 42.6%, respectively), erythromycin (3% and 1.7%, respectively) and azithromycin (1%). Multidrug resistance was more frequent among C. jejuni isolates (29.8%) than among C. coli isolates (18.2%).In conclusion, the results of this study demonstrated the importance of poultry meat as a source of Campylobacter spp., especially macrolide-resistant strains. The trend of decreasing Campylobacter spp. occurrence in retail poultry meat in this region of Poland requires further investigation, and monitoring.     

Assessment of the Campylobacter jejuni and C. coli in broiler chicken ceca by conventional culture and loop-mediated isothermal amplification method

In a two-year survey of the 24 Japanese broiler chicken flocks at 9 farms from 2013 to 2014, C. jejuni/C. coli prevalence was assessed in a total of 131 slaughtered broiler chicken cecal samples by conventional culture methods and loop-mediated isothermal amplification (LAMP) assay. While 93 samples were C. jejuni/C. coli-negative, 38 (29.0%) showed Campylobacter loads of between 6.4 and 9.0 log CFU/g of ceca in conventional culture methods. The performance of LAMP assay was 100% accurate in terms of diagnostic sensitivity (38/38), specificity (93/93). Furthermore, LAMP assay enabled direct screening of C. jejuni and C. coli in cecal samples from broiler chicken chickens as rapid and cost-effective detection within 90 min and less than 1 US dollar, which can help monitor release of Campylobacter-contaminated chicken into the food chain, thereby reducing the incidence and public health risk of campylobacteriosis. Seasonal changes in C. jejuni and C. coli prevalence in broiler chicken ceca were significantly correlated with the frequency of food poisoning incidents caused by these bacteria in Japan.     

Reduction of Campylobacter jejuni by natural antimicrobials in chicken meat-related conditions

Nowadays it is essential to test new preservation and decontamination procedures using naturally occurring chemicals against important pathogenic bacteria in meat. We tested the antimicrobial effect of rosemary extracts and the bacteriocin nisin against Campylobacter jejuni at a low storage temperature (8 °C) with or without short-term pre-freezing. The antimicrobial effect of rosemary extract was four times greater in laboratory media than in chicken meat juice. Furthermore, low temperature storage conditions prolonged the survival of C. jejuni in chicken meat juice. Nisin, with an approximately 1.0 log reduction was neither effective alone nor in combination with the extract. Pre-freezing with plant extract addition proved to be effective treatment by more than 3.0 log reduction in 48 h. The results in chicken meat food model again showed the synergistic effect of freezing and plant extract antimicrobial activity. As the combination of pre-freezing and plant extract treatment reduced the cell number by more than 2.0 log reduction, studies should be conducted to further evaluate this promising treatment for Campylobacter reduction in the poultry meat supply.     

Prevalence and fluoroquinolones resistance of Campylobacter and Salmonella isolates from poultry carcasses in Rio de Janeiro,Brazil

To investigate the prevalence of Campylobacter and Salmonella in poultry carcasses in state of Rio de Janeiro, Brazil, 60 samples from 6 slaughterhouses were collected over a period of 6 months. A total of 82 Campylobacter isolates were obtained from twenty seven (45%) positive chicken carcasses, including 44 isolates (53.66%) of Campylobacter jejuni and 38 (46.34%) of Campylobacter coli. The identification of all strains was confirmed by PCR. Salmonella was isolated from 4 (6.67%) carcasses by conventional method and was detected in 5 (8.33%) of 60 chicken carcasses by PCR. Two Salmonella Albany and two Salmonella Typhimurium were identified. Antimicrobial susceptibility testing was primarily done by the disk diffusion method and later by assessing minimum inhibitory concentrations (MICs) against all the isolates. All the Campylobacter isolates were resistant to ciprofloxacin and enrofloxacin. It was observed high MIC values for enrofloxacin (64 μg/mL) in one C. jejuni and two C. coli strains, and for ciprofloxacin (≥128 μg/mL) in one C. jejuni and three C. coli strains. No Salmonella isolate was resistant to these antibiotics by both methods. These findings reveal a broad extent of fluoroquinolone resistance in Campylobacter isolates from chicken carcasses in Brazil and underline the need for prudent use of these antibiotics in poultry production to minimize the spread of fluoroquinolone resistant Campylobacter.     

Efficacy of pulsed electric fields for the inactivation of indicator microorganisms and foodborne pathogens in liquids and raw chicken

This study investigated the ability of pulsed electric fields (PEF) to inactivate a range of microorganisms in liquid media and on raw chicken meat. The susceptibilities of ten Campylobacter isolates (seven Campylobacter jejuni isolates and three Campylobacter coli isolates), Escherichia coli (ATCC 25922) and Salmonella Enteritidis (ATCC 13076) to PEF in liquid media were investigated. All Campylobacter isolates tested in liquid were susceptible to PEF treatment (65 kV/cm, 5 μs, 500 Hz) with reductions of between 4.33 and 7.22 log₁₀ CFU/mL observed for the longest treatment (30 s). Significant differences in susceptibility were observed between Campylobacter isolates subjected to equivalent PEF treatments ranging from 2.41 to 5.19 log₁₀ CFU/mL. Campylobacter isolates processed in liquid media were found to be more sensitive to PEF than E. coli and S. Enteritidis (P < 0.05). The application of PEF (3.75 and 15 kV/cm, 10 μs, 5 Hz) to inoculated samples of raw chicken did not result in any significant reductions in total viable counts, Enterobacteriaceae, C. jejuni, E. coli or S. Enteritidis. Therefore, under the conditions used in this study, PEF technology may not be suitable as a food safety intervention measure for the control of microbial contaminants on broilers during processing although it may have potential to reduce contamination of process water (e.g. scald or spin chill water).     

Prevalence,antimicrobial resistance profiling and genetic diversity of Campylobacter jejuni and Campylobacter coli isolated from broilers at slaughter in China

A total of 651 samples from broiler cecal samples, carcasses, carcass parts collected at the slaughterhouse level in Sichuan Province of China were examined for the occurrence of Campylobacter jejuni and Campylobacter coli. After confirmed by species-specific multiplex PCR, the recovered isolates were examined for resistance to antimicrobials using an agar dilution method and investigated for the mutation of gyrA, tetO gene and V domain of 23S rRNA as well as the presence of class 1 integron and the associated gene cassettes. In addition, the genotype relatedness of the isolates was determined by pulsed-field gel electrophoresis (PFGE) profiling. The prevalence of Campylobacter was 56.1% in cecal samples, 31.0% in carcasses and 17.0% in carcass parts, respectively. Among them, C. jejuni accounted for 24.6% and C. coli occupied 20.0% of the samples. The strains of C. jejuni were most frequently resistant to ciprofloxacin (88.1%), followed by resistance to tetracycline (79.4%) and levofloxacin (78.1%). Most of the C. coli isolates were resistant to ciprofloxacin (100%), tetracycline (98.5%), levofloxacin (98.5%), clindamycin (98.5%) and erythromycin (93.9%). Antimicrobial resistance profiling showed that 93.7% of campylobacters were multidrug resistant (MDR) strains. Moreover, class 1 integrons were detected in 98.6% of MDR campylobacters, among which 98.7% were positive for C. jejuni and 98.5% for C. coli. Three kinds of gene cassettes-associated amplicons were identified and the amplicons profile of 1000–750–500–250 bp was the predominant pattern linked to the aminoglycoside resistance gene of aadA2. The presence of mutation in gyrA, tetO and 23S rRNA between C. jejuni and C. coli varied from 89.7% to 97.3%, 96.6% to 94.1%, and 95.0% to 96.7%, respectively. Finally, the results of PFGE indicated that, 33 PFGE profiles were generated among 78 isolates of C. jejuni and the similarity level ranged from 42.1% to 99.1%. By contrast, 15 PFGE patterns were produced among 68 C. coli isolates sharing a similarity level of 54.0%–99.7%. Comparison of the PFGE and antimicrobial resistance profiles of the isolates reflected the high genetic diversity of Campylobacter tested. A poor correlation among the antimicrobial resistance patterns, resistance determinants and PFGE genotypes was observed in C. jejuni. Our study showed that there were several points of cross-contamination during broiler slaughter, and a high diversity of PFGE types in the Campylobacter isolates with high resistances to ciprofloxacin and tetracycline.     

Antibacterial activity of Oregano,Rosmarinus and Thymus essential oils against Staphylococcus aureus and Listeria monocytogenes in beef meatballs

Antimicrobial activity of five essential oils (EOs) was investigated up to 72 h against foodborne pathogens (Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritidis, Campylobacter jejuni) through disk diffusion and determination of Minimum Inhibitory Concentrations. The most active EOs were Thymus vulgaris and Origanum vulgare, followed by Cinnamomum zeylanicum, Rosmarinus officinalis, and Salvia officinalis. The antimicrobial activity of O. vulgare, Rosmarinus officinalis and T. vulgaris was investigated against five enterotoxin producers of S. aureus and five L. monocytogenes strains, for different amounts of time (up to 14 days), at 4 °C, in meatballs. Concentrations of 2% and 1% restricted the growth of both the pathogens but, as a result of panel tests, altered the meat flavor. The cooked meatballs containing 0.5% of EO were acceptable in terms of taste, and the oils were able to suppress concentrations of <10² CFU/g of the pathogens, revealing the potential use of R. officinalis, T. vulgaris and O. vulgare as food preservatives at this concentration.     

Campylobacter jejuni biofilm cells become viable but non-culturable (VBNC) in low nutrient conditions at 4 °C more quickly than their planktonic counterparts

Campylobacter jejuni remains the leading cause of foodborne disease in the developed world. In order to assess the ability of biofilm cells to enter and survive in a viable but non-culturable state, biofilm and planktonic cells of three strains of C. jejuni were incubated at 4 °C in phosphate buffered saline. Culturability was monitored by standard drop plating on Mueller Hinton agar and viability was measured using the LIVE/DEAD^® BacLight™ assay which assesses membrane integrity. Both biofilm and planktonic cells became non-culturable prior to becoming non-viable. Biofilm cells became non-culturable as early as 10 days for one strain, while planktonic cells became non-culturable after 30–40 days of treatment. Planktonic cells were still viable after 60 days of stress treatment. Biofilm cells showed significantly reduced viability by day 50 for the two clinical isolates and by day 60 for the poultry isolate. Of the media assessed for their ability to extend the culturability of the VBNC cells, Campylobacter Agar Base with the addition of Campylobacter Growth Supplement was most successful at prolonging culturability, but even with enrichment in Bolton broth, cells still remained viable and potentially infectious, longer than they were culturable.     

Inactivation of foodborne pathogens on gala apples by application of antimicrobial waxes

There is a need for effective postharvest controls capable of inactivating bacterial foodborne pathogens, which can be applied to the organic and conventional apple industries. This study evaluated the efficacy of natural antimicrobials (essential oils or cultured dextrose) when incorporated into carnauba wax and applied to apples. Organic Gala apples were spot inoculated with a five strains/serovars cocktail (∼9 Log CFU/mL) of Listeria monocytogenes, Shiga-toxigenic E. coli O157:H7, or Salmonella. Inoculated apples were coated with organic carnauba wax containing a 1% and 2% (v/v) mixture of essential oils (EOs) in equal proportions (oregano, clove bud, cinnamon bark, and coriander seed) or commercially cultured dextrose at 0.5% (w/v). Apples coated with carnauba wax only and uncoated apples were used as control treatments. Apples were stored at 20 °C and sampled for up to 40 days. Five treatments with three biological replicates and three samples per replicate were used for each treatment (n = 9). A sensory discrimination test was used to identify differences between waxed apples for treatments with the greatest efficacy. Carnauba wax containing 2% EOs was the most effective treatment for inactivating target foodborne pathogens inoculated on apples for 40 days. This treatment showed 4.05, 1.38 and 2.81 Log CFU/apple reduction in L. monocytogenes, E. coli O157:H7, and Salmonella, respectively, compared to uncoated apples. Carnauba wax containing 2% EOs showed significantly (P ≤ 0.001) lower populations of L. monocytogenes and Salmonella compared with 1% EOs, 0.5% cultured dextrose, or wax-only control. In contrast, there were no significant differences (P > 0.05) for E. coli O157:H7. Sensory evaluation showed that panelists could detect differences for apples treated with wax containing 2% EOs, but not for 1% EOs compared to wax-only control. This study provides information to the organic and conventional apple industry about the efficacy of antimicrobial waxes to inactivate bacterial foodborne pathogens.     

Antibiofilm activity of essential oils and plant extracts against Staphylococcus aureus and Escherichia coli biofilms

Bacterial biofilms pose health risks in clinical environments, food industry and drinking water systems. Here, we investigated in vitro antibiofilm activities of essential oils (EO) and plant extracts of peppermint (Mentha × piperita L.), coriander (Coriandrum sativum L.), and anise (Pimpinella anisum L.). Minimum inhibitory concentration assay (MIC) was carried out using two-fold serial dilution method and MTT assay against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Biofilm growth and development were assessed using crystal violet (CV) and XTT reduction assays. Antibacterial activity was observed for almost all plant extracts and all EOs against both bacterial strains with stronger activity against S. aureus. All EOs (at MIC value of 0.8 to 0.63 μl/ml) and 8 out of 14 plant extracts (at MIC value of 2–4 mg/ml) inhibited bacteria cell attachment of both bacteria. CV and XTT reduction assay for the plant extracts and EOs with inhibition of bacteria attachment by at least 50%, demonstrated that coriander EO had the highest antibiofilm activity against biofilm formed by both tested bacteria (S. aureus and E. coli) at lowest MIC value 0.8 μl/ml and 1.6 μl/ml, respectively, indicating further investigations due to the oil's high antibiofilm activity potential.     

Prevalence and pattern of antibiotic resistance of Campylobacter spp. in poultry meat in Southern Italy

Campylobacter spp. is one of the most common cause of sporadic human foodborne illness in industrialized countries, and concern has been raised by the emergence of strains showing antibiotic resistance. The aim of this study was to investigate prevalence of Campylobacter spp. and pattern of antibiotic resistance in samples of poultry raw meat sold in retail outlets in Southern Italy.A total of 208 samples of chicken and turkey raw meat collected from randomly selected retail butchers' shops in Catanzaro (Italy) were processed for the presence of Campylobacter spp.Campylobacter spp. contaminated 43 samples of poultry product. The most frequent isolates were Campylobacter coli (34.9%) and Campylobacter jejuni (32.6%). The lowest resistance was found for gentamycin (27.9%) and cloramphenicol (32.6%). We also investigated prevalence of sensitivity to the most important antibiotics and we found that only 20.9% isolates were sensible to both ciprofloxacin and erythromycin.Our findings revealed a reduction in the overall contamination by Campylobacter spp. in raw meat. However, resistant and particularly multi-resistant strains were alarmingly spread, representing an increasing phenomenon that demands enforced interventions at multidisciplinary levels.     

Prevalence and antimicrobial resistance of Campylobacter species isolates in ducks and geese

A total of 471 duck and goose intestinal content samples were collected from wet markets and were determined for the prevalence of Campylobacter spp. For the detected isolates, resistance to selected antimicrobial agents was identified. Campylobacter spp. was detected in 114/291 duck samples (39.2%) and 47/180 goose samples (26.1%). Among the 161 isolated Campylobacter spp., 85.7% and 14.3% were Campylobacter jejuni and Campylobacter coli, respectively. Resistance to ciprofloxacin (82.6%), tetracycline (77%) and nalidixic acid (75.2%) was particularly high in the tested Campylobacter isolates. However, all isolates were susceptible to gentamicin, neomycin, streptomycin, neomycin and ampicillin. The presence of Campylobacter spp., as well as the detection of multidrug-resistant isolates in this study, indicates that consuming of duck and goose meat might be a potential campylobacteriosis risk in this region.     

Potential of berry extracts to control foodborne pathogens

Globally, foodborne diseases continues to be a serious public health problem. Among the infectious bacteria implicated in these diseases, non-typhoidal Salmonella enterica (NTS) serovars are the major cause of hospitalization and death, followed by Campylobacter, Clostridium perfringens, Escherichia coli O157:H7, and Listeria monocytogenes. In addition, the emergence and spread of antibiotic-resistance strains among these bacteria is becoming a worldwide food safety issue. This rise of resistance led to the restriction of antibiotics use in animal productions in the European Union and application of a possible similar action in the North America. To limit the use of antibiotics in agricultures while satisfying the consumer demands, effective alternative approaches to maintain the animal health and productivity as well as to preserve food need to be explored. In this context, the plant-derived antibacterial compounds could provide novel approaches to control pathogenic bacteria in food industry. In this paper, we review the potential of three different berries (cranberries, blueberries and strawberries) extracts, as alternative antibacterial products against foodborne pathogens. These extracts show various antimicrobial activities against Gram positive (Listeria, Staphylococcus aureus, and Clostridium perfringens) and Gram negative (Salmonella enterica, E. coli and Campylobacter spp.) bacteria. Berry extracts seem to have a pleotropic mode of actions against foodborne bacteria. Several studies on proanthocyanidins from cranberry demonstrated its bactericidal action through anti-adhesion activities and free iron sequestration. Blueberry phenolics were reported to decrease cell auto-aggregation, motility and affect the cellular hydrophobicity. Similar action was observed with strawberry extracts due to their immobilizing capacity. Key research gaps include the effects of processing, bioavailability and detail mechanisms of action of berry compounds.     

Determination of antimicrobial effect of mint and basil essential oils on survival of E. coli O157:H7 and S. typhimurium in fresh-cut lettuce and purslane

In this research, mint and basil essential oils at concentrations of 0.01 ml/L, 0.032 ml/L or 0.08 ml/L were used for disinfection treatments of fresh-cut lettuce and purslane samples inoculated with Salmonella typhimurium or Escherichia coli 0157:H7. Disinfection treatment time was applied as 10 min (short) or 15 min (long). Disinfected samples were packaged aerobically and stored at refrigerator +4 °C for 7 days. It was observed that mint and basil essential oils showed antimicrobial effect on the survival of E. coli O157:H7 and S. typhimurium inoculated into lettuce and purslane samples during refrigerated storage. Mint essential oil showed higher antimicrobial effect on pathogens when compared to basil essential oil. Mint and basil essential oils at concentration of 0.08 ml/L were the most effective antimicrobial treatment against pathogens in two different vegetable. S. typhimurium was more resistant against basil oil in lettuce samples when compared to its resistance against basil oil in purslane samples, whereas E. coli O157:H7 was more resistant to mint oil in purslane samples when compared to its resistance against mint oil in lettuce samples.