Resistance In Foodborne Pathogens Research Articles

Milk phospholipids-based nanostructures functionalized with rhamnolipids and bacteriocin: Intrinsic and synergistic antimicrobial activity for cheese preservation

Milk fat globule membrane (MFGM) phospholipids-based nanostructures were developed and their functionalization with rhamnolipids (RLs) was carried out to enhance the preservation of cheese against resistant foodborne pathogens i.e., Listeria monocytogenes and Escherichia coli. Void (without nisin) and nisin-loaded RLs functionalized MFGM nanostructures (RLs-MFGM-NS) were fabricated by ultrasonication-assisted self-assembly method. Cubic morphology of void and loaded RLs-MFGM-NS and pristine MFGM nanostructures (MFGM-NS) was observed under scanning electron microscopy (SEM), which indicated uniform size ranging from 43 nm (void RLs-MFGM-NS) to 194 nm (loaded RLs-MFGM-NS). FTIR analyses confirmed the electrostatic interaction, predominantly H-bonding and linkage of carboxyl ester group of MFGM with C–H group in RLs after functionalization of NS. Furthermore, quantitative antimicrobial assay on cheese slices confirmed the broad-spectrum potential of intrinsically active nanostructures (due to RLs) having synergistic activity with nisin against L. monocytogenes and E. coli. Hence, nisin-loaded RLs-MFGM-NS can be applied as promising bioactive additives for sustained preservation of cheese.

Molecular Detection of Fluoroquinolone Resistance among Multidrug-, Extensively Drug-, and Pan-Drug-Resistant Campylobacter Species in Egypt.

In recent times, resistant foodborne pathogens, especially of the Campylobacter species, have created several global crises. These crises have been compounded due to the evolution of multidrug-resistant (MDR) bacterial pathogens and the emergence of extensively drug-resistant (XDR) and pan-drug-resistant (PDR) strains. Therefore, this study aimed to investigate the development of resistance and the existence of both XDR and PDR among Campylobacter isolates. Moreover, we explored the use of the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) technique for the detection of fluoroquinolone (FQ)-resistant Campylobacter isolates. A total of 120 Campylobacter isolates were identified depending on both phenotypic and genotypic methods. Of note, cefoxitin and imipenem were the most effective drugs against the investigated Campylobacter isolates. Interestingly, the majority of our isolates (75%) were MDR. Unfortunately, both XDR and PDR isolates were detected in our study with prevalence rates of 20.8% and 4.2%, respectively. All FQ-resistant isolates with ciprofloxacin minimum inhibitory concentrations ≥4 µg/mL were confirmed by the genetic detection of gyrA chromosomal mutation via substitution of threonine at position 86 to isoleucine (Thr-86-to-Ile) using the PCR-RFLP technique. Herein, PCR-RFLP was a more practical and less expensive method used for the detection of FQ resistant isolates. In conclusion, we introduced a fast genetic method for the identification of FQ-resistant isolates to avoid treatment failure through the proper description of antimicrobials.

Prevalence, Phylogroups and Antimicrobial Susceptibility of Escherichia coli Isolates from Food Products.

The emergence of multi-drug resistant E. coli is an important matter of increasing considerable concern to global public health. The aim of this study was to investigate the incidence, antibiotic resistance pattern and phylogroups of E. coli isolates obtained from raw milk, vegetable salad and ground meat samples collected from Qazvin Province (Iran). Culture-based techniques, Kirby-Bauer disk diffusion susceptibility testing and PCR assays were used to determine the incidence rate, antimicrobial resistance pattern and phylogenetic groups of the E. coli isolates. The E. coli isolates were highly resistant to amoxicillin (79.1%), trimethoprim-sulfamethoxazole (70.8%), amoxicillin-clavulanic acid (62.5%), tetracycline (54.1%), chloramphenicol (54.1%), nitrofurantoin (54.1%), ampicillin (45.8%), streptomycin (45.8%), and kanamycin (33.3%); and completely susceptible to norfloxacin and azithromycin and 70.8% of the isolates were multi-drug resistant. Most E. coli isolates (46%) belonged to phylogroup A. Novel, practical, efficient food safety control and surveillance systems of multi-drug resistant foodborne pathogens are required to control the foodborne pathogen contamination.

Antimicrobial Resistance in Africa-How to Relieve the Burden on Family Farmers.

Although currently available data indicate that Africa has the lowest usage of antimicrobials in animals in the world (adjusted by animal biomass), data show a high prevalence of antimicrobial resistance in foodborne pathogens isolated from animals and animal products. Apart from the lack of solid data on antimicrobial use in many countries in Africa, different hypotheses could explain this situation. Qualitative interviews of farmers show a lack of knowledge and uninformed use of antimicrobials. Considering the development of animal farming to meet an increasing demand for proteins, this deficiency represents a serious public health issue. We advocate for policies that consider the specific challenges faced by family farmers in Africa, to simultaneously improve access to veterinary drugs while strengthening the regulation of their use. We propose a global approach targeting the agri-food system, offering innovative social and technical interventions on antimicrobial usage, adapted to family farmers.

Integrated Surveillance for Antimicrobial Resistance in Salmonella From Clinical and Retail Meat Sources Reveals Genetically Related Isolates Harboring Quinolone- and Ceftriaxone-Resistant Determinants.

BackgroundAntimicrobial resistance in foodborne pathogens, including nontyphoidal Salmonella (NTS), is a public health concern. Pennsylvania conducts integrated surveillance for antimicrobial resistance in NTS from human and animal sources.MethodsDuring 2015–2017, clinical laboratories submitted 4478 NTS isolates from humans and 96 isolates were found in 2520 retail meat samples. One hundred nine clinical isolates that shared pulsed-field gel electrophoresis patterns with meat isolates and all strains from meat samples were tested for susceptibility to antimicrobial agents. Six clinical and 96 NTS isolates from meat sources (total 102) were analyzed by whole-genome sequencing (WGS).ResultsTwenty-eight (25.7%) of the 109 clinical NTS and 21 (21.9%) of strains from meat sources had resistance to ≥3 antimicrobial drug classes (multidrug resistance). Sixteen of the 102 (15.7%) isolates analyzed by WGS had resistance mechanisms that confer resistance to expanded-spectrum cephalosporins, such as ceftriaxone. We identified blaCTX-M-65 in 2 S. Infantis isolates from clinical and 3 S. Infantis isolates from meat sources. These 5 blaCTX-M-65–positive S. Infantis strains carried ≥5 additional resistance genes plus a D87Y mutation in gyrA that encodes fluoroquinolone resistance. WGS showed that isolates from patients and meat samples were within ≤10 and ≤5 alleles for S. Infantis and S. Reading, respectively.ConclusionsA significant proportion of NTS isolates from human and animal sources were multidrug resistant and 16% had genetic mechanisms that confer resistant to ceftriaxone. These results emphasize need for integrated surveillance in healthcare and agricultural settings.

Genomic characterization of conjugative plasmids carrying the mcr-1 gene in foodborne and clinical strains of Salmonella and Escherichia coli

To date, the genomic characterization of foodborne bacteria carrying the mobile colistin resistance gene mcr-1 and transferability of mcr-1-carrying plasmids between wild-type bacteria have not been studied in detail. We retrospectively investigated the prevalence of mcr-1-positive Salmonella and Escherichia coli isolated from retail food products, food supply chain, and clinical samples across China in the last decade (2006–2017). The horizontal transfer of mcr-1-bearing plasmids and their complete nucleotide sequence were characterized using conjugation, S1-nuclease pulsed-field gel electrophoresis, and Southern hybridization, coupled with Illumina and Nanopore sequencing. Twelve (0.67%) mcr-1-positive strains were identified from 1789 non-duplicated isolates, including 1283 Salmonella and 506 E. coli. Eleven (21.7‰) mcr-1-positive E. coli strains were identified from the isolates collected during 2006–2017, which was significantly more prevalent than mcr-1-positive Salmonella in this period (0.78‰, 1/1283; P < 0.05). All donors (nine mcr-1-positive isolates, designated as D1–9) were multidrug resistant with diverse antimicrobial susceptibility profiles and were resistant to polymyxin B. mcr-1-carrying plasmids in donors were successfully transferred to recipients at frequencies of 4.6 × 10−2 to 6.25 × 10−4 per recipient cell. A ~33 kb IncX4-type plasmid in D1, which carried mcr-1 with the insertion sequence IS26 upstream, was effectively transferred to recipient R1. D2, D4, and their corresponding transconjugants harbored a ~60 kb IncI2-type plasmid with the insertion sequence ISApl1 upstream of mcr-1. A ~60 kb conjugative mcr-1-bearing plasmid derived from D5 also belonged to type IncI2 and contained the mcr-1 gene cassette ISEcp1-blaCTX-M-55-mcr-1-PAP2. In conclusion, mcr-1 was commonly detected in type IncI2, IncX4, and IncHI2 plasmids and mcr-1 encoding colistin resistance was successfully transferred between foodborne and clinical strains of E. coli and Salmonella isolated in China. mcr-1 gene cassettes including IS26-mcr-1-PAP2, ISAPl1-mcr-1-PAP2, and ISEcp1-blaCTX-M-55-mcr-1-PAP2 can be transferred horizontally between wild-type bacteria via conjugation. The new mcr-1 gene cassette discovered in this study provided evidence for co-transfer of mcr-1 and other antibiotic resistance genes. This finding suggests that antibiotics, other than colistin, should be used in combination for the treatment and prevention of diseases caused by foodborne pathogens. The co-transfer of mcr-1 and other antibiotic resistance genes will also enhance antibiotic resistance in foodborne pathogens.

Absence of high priority critically important antimicrobial resistance in Salmonella sp. isolated from Australian commercial egg layer environments

The development of antimicrobial resistance in foodborne pathogens is a growing public health concern. This study was undertaken to determine the antimicrobial susceptibility of Salmonella enterica subspecies enterica isolated from the Australian commercial egg layer industry. S. enterica subspecies enterica (n=307) isolated from Australian commercial layer flock environments (2015–2018) were obtained from reference, research and State Government laboratories from six Australian states. All Salmonella isolates were serotyped. Antimicrobial susceptibility testing (AST) for 16 antimicrobial agents was performed by broth microdilution. Antimicrobial resistance genes and sequence types (STs) were identified in significant isolates by whole genome sequencing (WGS). Three main serotypes were detected, S. Typhimurium (n=61, 19.9%), S. Senftenburg (n=45, 14.7%) and S. Agona (n=37, 12.1%). AST showed 293/307 (95.4%) isolates were susceptible to all tested antimicrobial agents and all isolates were susceptible to amoxicillin-clavulanate, azithromycin, ceftiofur, ceftriaxone, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin and trimethoprim-sulfamethoxazole. Low levels of non-susceptibility were observed to streptomycin (2.3%, n=7), sulfisoxazole (2.0%, n=6), chloramphenicol (1.3%, n=4) and tetracycline (1.0%, n=3). Very low levels of non-susceptibility were observed to ampicillin (2/307; 0.7%) and cefoxitin (2/307; 0.7%). Two isolates (S. Havana and S. Montevideo), exhibited multidrug-resistant phenotypes to streptomycin, sulfisoxazole and tetracycline and possessed corresponding antimicrobial resistance genes (aadA4, aac(6′)-Iaa, sul1, tetB). One S. Typhimurium isolate was resistant to ampicillin and tetracycline, and possessed both tetA and blaTEM-1B. WGS also identified these isolates as belonging to ST4 (S. Montevideo), ST578 (S. Havana) and ST19 (S. Typhimurium). The absence of resistance to highest priority critically important antimicrobials as well as the extremely low level of AMR generally among Australian commercial egg layer Salmonella isolates likely reflect Australia's conservative antimicrobial registration policy in food-producing animals and low rates of antimicrobial use within the industry.

Thymol Nanoemulsion: A New Therapeutic Option for Extensively Drug Resistant Foodborne Pathogens.

Foodborne pathogens have been associated with severe and complicated diseases. Therefore, these types of infections are a concern for public health officials and food and dairy industries. Regarding the wide-spread multidrug resistant (MDR) and extensively drug resistant (XDR) foodborne pathogens such as Salmonella Enteritidis (S. Enteritidis), new and alternative therapeutic approaches are urgently needed. Therefore, we investigated the antimicrobial, anti-virulence, and immunostimulant activities of a stable formulation of thymol as thymol nanoemulsion in an in vivo approach. Notably, treatment with 2.25% thymol nanoemulsion led to a pronounced improvement in the body weight gain and feed conversion ratio in addition to decreases in the severity of clinical findings and mortality percentages of challenged chickens with XDR S. Enteritidis confirming its pronounced antimicrobial activities. Moreover, thymol nanoemulsion, at this dose, had protective effects through up-regulation of the protective cytokines and down-regulation of XDR S. Enteritidis sopB virulence gene and interleukins (IL)-4 and IL-10 cytokines as those hinder the host defenses. Furthermore, it enhanced the growth of gut Bifidobacteria species, which increases the strength of the immune system. For that, we suggested the therapeutic use of thymol nanoemulsion against resistant foodborne pathogens. Finally, we recommended the use of 2.25% thymol nanoemulsion as a feed additive for immunocompromised individuals as well as in the veterinary fields.

High prevalence of multidrug resistant Escherichia coli isolated from fresh vegetables sold by selected formal and informal traders in the most densely populated Province of South Africa

Contaminated fresh produce has increasingly been implicated in foodborne disease outbreaks. As microbiological safety surveillance in South Africa is limited, a total of 545 vegetable samples (spinach, tomato, lettuce, cucumber, and green beans) were purchased from retailers, street traders, trolley vendors and farmers' markets. Escherichia coli, coliforms and Enterobacteriaceae were enumerated and the prevalence of Escherichia coli, Salmonella spp. and Listeria monocytogenes determined. E. coli isolates were characterized phenotypically (antibiotic resistance) and genotypically (diarrheagenic virulence genes). Coliforms, E. coli and Enterobacteriaceae counts were mostly not significantly different between formal and informal markets, with exceptions noted on occasion. When compared to international standards, 90% to 98% tomatoes, 70% to 94% spinach, 82% cucumbers, 93% lettuce, and 80% green bean samples, had satisfactory (≤ 100 CFU/g) E. coli counts. Of the 545 vegetable samples analyzed, 14.86% (n = 81) harbored E. coli, predominantly from leafy green vegetables. Virulence genes (lt, st, bfpA, eagg, eaeA, stx1, stx2, and ipaH) were not detected in the E. coli isolates (n = 67) characterized, however 40.30% were multidrug-resistant. Resistance to aminoglycosides (neomycin, 73.13%; gentamycin, < 10%), penicillins (ampicillin, 38.81%; amoxicillin, 41.79%; augmentin, < 10%), sulfonamides (cotrimoxazole, 22.39%), tetracycline (19.4%), chloramphenicol (11.94%), cephalosporins (cefepime, 34.33%), and carbapenemases (imipenem, < 10%) were observed. This study highlights the need for continued surveillance of multidrug resistant foodborne pathogens in fresh produce retailed formally and informally for potential consumer health risks. PRACTICAL APPLICATION: The results indicate that the microbiological quality of different vegetables were similar per product type, regardless of being purchased from formal retailers or informal street traders, trolley vendors or farmers' markets. Although no pathogenic bacteria (diarrheagenic E. coli, Salmonella spp. or L. monocytogenes) were isolated, high levels of multidrug-resistance was observed in the generic E. coli isolates. These findings highlight the importance of microbiological quality surveillance of fresh produce in formal and informal markets, as these products can be a reservoir of multidrug resistant bacteria harboring antibiotic resistance and virulence genes, potentially impacting human health.

Selection for Antimicrobial Resistance in Foodborne Pathogens through Exposure to UV Light and Nonthermal Atmospheric Plasma Decontamination Techniques

This study was aimed at assessing whether the repeated exposure of 12 strains of Salmonella spp., Escherichia coli, and Listeria monocytogenes to alternative nonthermal decontamination techniques with UV light (UV-C) and nonthermal atmospheric plasma (NTAP) may cause the emergence of variants showing increased resistance to clinically relevant antibiotics (ampicillin, cefotaxime, ciprofloxacin, gentamicin, streptomycin, tetracycline, erythromycin, vancomycin, and colistin). UV-C and NTAP treatments were applied on the surface of inoculated brain heart infusion (BHI) agar plates. Survivors were recovered and after 24 h of growth in BHI broth were again subjected to the decontamination treatment; this was repeated for 10 consecutive cycles. A total of 174 strain/decontamination technique/antibiotic combinations were tested, and 12 variant strains with increased resistance to one of the antibiotics studied were identified, with the increases in the MICs in Mueller-Hinton broth ranging from 2- to 256-fold. The variant strains of Salmonella spp. isolated were further characterized through phenotypic screenings and whole-genome sequencing (WGS) analyses. Most changes in susceptibility were observed for antibiotics that act at the level of protein synthesis (aminoglycosides, tetracyclines, and glycylcyclines) or DNA replication (fluoroquinolones), as well as for polymyxins. No changes in resistance to β-lactams were detected. WGS analyses showed the occurrence of sequence alterations in some antibiotic cellular targets (e.g., gyrA for ciprofloxacin-resistant variants, rpsL for a streptomycin-resistant variant), accompanied by variations in stress response regulators and membrane transporters likely involved in the nonselective efflux of antibiotics, which altogether resulted in a low- to medium-level increase in microbial resistance to several antibiotics.IMPORTANCE The emergence and spread of antibiotic resistance along the food chain can be influenced by the different antimicrobial strategies used from farm to fork. This study evidences that two novel, not yet widely used, nonthermal microbial decontamination techniques, UV light and nonthermal atmospheric plasma, can select variants with increased resistance to various clinically relevant antibiotics, such as ciprofloxacin, streptomycin, tetracycline, and erythromycin. Whole-genome analysis of the resistant variants obtained for Salmonella spp. allowed identification of the genetic changes responsible for the observed phenotypes and suggested that some antimicrobial classes are more susceptible to the cross-resistance phenomena observed. This information is relevant, since these novel decontamination techniques are being proposed as possible alternative green techniques for the decontamination of environments and equipment in food and clinical settings.

Prevalence and trend analysis of antimicrobial resistance in clinical Escherichia coli isolates collected from diseased pigs in the USA between 2006 and 2016.

Antimicrobial resistance (AMR) is an emerging threat to both human and animal health. Antimicrobial use and resistance in food animal production, including swine, has received increased scrutiny as a source of resistant foodborne pathogens. Continuous surveillance of AMR in bacterial isolates of swine origin can guide in conservation of antimicrobials used in both human and swine medicine. The objective of this study was to evaluate the prevalence and trends of the phenotypic AMR in Escherichia coli of swine origin isolated from clinical samples at the Minnesota Veterinary Diagnostic laboratory between 2006 and 2016. The prevalence of resistance to ampicillin, tetracyclines and sulphadimethoxine remained greater than 50% throughout the period. There was a drastic change in enrofloxacin resistance, increasing from less than 1% to more than 20% between 2006 and 2016 (annual relative increase of 57% between 2006 and 2013 and 16% between 2013 and 2016). The prevalence of resistance to other antimicrobials remained constant (ceftiofur, oxytetracycline and chlortetracycline) or changed significantly (annual relative changes of less than 10%) for at least some time-period between 2006 and 2016 (ampicillin, florfenicol, gentamicin, neomycin, sulphadimethoxine, trimethoprim-sulphamethoxazole and spectinomycin). Rarefaction analysis revealed an increase in the number of unique combinations of AMRs per year. Network analysis was performed by estimating and plotting partial correlations between minimum inhibitory concentrations (MICs) of various antimicrobials. An increase in strength of these networks was observed, particularly in networks created after 2010, which can be indicative of increased multiple AMR in these isolates. These results provide valuable insight into the trends in AMR in E. coli of swine origin in the USA and act as supplementary information to the existing active AMR surveillance systems.

Investigation of Incidents and Trends of Antimicrobial Resistance in Foodborne Pathogens in Eight Countries from Historical Sample Data.

Antimicrobial resistance (AMR) causes millions of illnesses every year, threatening the success of lifesaving antibiotic therapy and, thus, public health. To examine the rise and spread of antimicrobial resistance around the world, our study performs a multivariate statistical analysis of antimicrobial resistance gene data from eight different countries: the US, the UK, China, Brazil, Mexico, Canada, Australia, and South Africa. Multi-dimensional data points were projected onto a two-dimensional plane using principal component analysis and organized into a dendrogram utilizing hierarchical clustering to identify significant AMR genes and pathogens. Outlier genes/pathogens were typically involved in high occurrences of antimicrobial resistance, and they were able to indicate the trend of antimicrobial resistance in the future. Statistical analysis of the data identified: (1) tet(A), aph(3″)-Ib, aph(6)-Id, blaEC, blaTEM-1, qacEdelta1, sul1, sul2, and aadA1 as the nine most common AMR genes among the studied countries; (2) Salmonella enterica and E. coli and Shigella as the most common AMR foodborne pathogens; and (3) chicken as the most prevalent meat carrier of antimicrobial resistance. Our study shows that the overall number of reported antimicrobial resistance cases in foodborne pathogens is generally rising. One potential contributing factor for this is the increasing antimicrobial usage in the growing livestock industry.

Determination of colistin resistance in Escherichia coli isolates from foods in Turkey, 2011-2015

Antimicrobial resistance of pathogenic microorganisms is an emerging public health concern. Intensive use of antibiotics in food animals might increase antimicrobial resistance in foodborne pathogens. Colistin is a last resort antibiotic for treatment of multidrug resistant (MDR) Gram negative pathogens. The recent antimicrobial resistance studies revealed a mobile antimicrobial resistance gene (mcr) that provides resistance to colistin. Furthermore, the gene has been found in different genera. Therefore, the aim of this study was to determine colistin resistance of Escherichia coli isolates (N=48) isolated in between 2011 and 2015 from food samples in Turkey. In addition, 5 mcr genes and their variants were screened by performing PCR on resistant isolates. 4 E. coli isolates were found resistant to colistin above the epidemiological cut-off value (Minimum inhibitory concentration (MIC) > 2mg/L). None of the resistant isolates had the mcr genes. Further studies with human and food isolates should be conducted to figure out which gene or genes are responsible for colistin resistance.

MALDI-TOF Mass Spectrometry and Specific Biomarkers: Potential New Key for Swift Identification of Antimicrobial Resistance in Foodborne Pathogens.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is today the reference method for direct identification of microorganisms in diagnostic laboratories, as it is notably time- and cost-efficient. In the context of increasing cases of enteric diseases with emerging multi-drug resistance patterns, there is an urgent need to adopt an efficient workflow to characterize antimicrobial resistance (AMR). Current approaches, such as antibiograms, are time-consuming and directly impact the “patient-physician” workflow. Through this mini-review, we summarize how the detection of specific patterns by MALDI-TOF MS, as well as bioinformatics, become more and more essential in research, and how these approaches will help diagnostics in the future. Along the same lines, the idea to export more precise biomarker identification steps by MALDI-TOF(/TOF) MS data towards AMR identification pipelines is discussed. The study also critically points out that there is currently still a lack of research data and knowledge on different foodborne pathogens as well as several antibiotics families such as macrolides and quinolones, and many questions are still remaining. Finally, the innovative combination of whole-genome sequencing and MALDI-TOF MS could be soon the future for diagnosis of antimicrobial resistance in foodborne pathogens.

Biocide-Tolerant Listeria monocytogenes Isolates from German Food Production Plants Do Not Show Cross-Resistance to Clinically Relevant Antibiotics.

Contamination of food during processing is recognized as a main transmission route of Listeria monocytogenes To prevent microbial contamination, biocides are widely applied as disinfectants in food processing plants. However, there are concerns about the development of antimicrobial resistance in foodborne pathogens due to widespread biocide usage. In our study, 93 L. monocytogenes isolates from German food production facilities were (i) tested for biocide and antibiotic susceptibility using broth microdilution assays, (ii) analyzed for links between reduced biocide susceptibility and antibiotic resistance, and (iii) characterized by whole-genome sequencing, including the detection of genes coding for biocide tolerance, antibiotic resistance, and other virulence factors. Fifteen L. monocytogenes isolates were tolerant to benzalkonium chloride (BAC), and genes conferring BAC tolerance were found in 13 of them. Antibiotic resistance was not associated with biocide tolerance. BAC-tolerant isolates were assigned to 6 multilocus sequence type (MLST) clonal complexes, and most of them harbored internalin A pseudogenes with premature stop codons or deletions (n = 9). Our study demonstrated a high genetic diversity among the investigated isolates including genotypes that are frequently involved in human infections. Although in vitro adaptation studies to biocides have raised concerns about increasing cross-resistance to antibiotics, our results do not provide evidence for this phenomenon in field isolates.IMPORTANCE Foodborne pathogens such as L. monocytogenes can persist in food production environments for a long time, causing perennial outbreaks. Hence, bacterial pathogens are able to survive cleaning and disinfection procedures. Accordingly, they may be repeatedly exposed to sublethal concentrations of disinfectants, which might result in bacterial adaptation to these biocides. Furthermore, antibiotic coresistance and cross-resistance are known to evolve under biocide selection pressure in vitro Hence, antimicrobial tolerance seems to play a crucial role in the resilience and persistence of foodborne pathogens in the food chain and might reduce therapeutic options in infectious diseases.

Antimicrobial and antibiofilm potential of bacteriocin loaded nano-vesicles functionalized with rhamnolipids against foodborne pathogens

Synthetic lipid membranes are considered as promising food-grade nano vesicles (NVs), but their functionalization is required to empower them as active-nano vesicle systems. In this study, rhamnosomes (RS) were developed by engineering the membrane of nano-liposomes with antimicrobial surfactant i.e. rhamnolipids (RL). Intrinsically active rhamnosome nano-vesicles (RSNVs) were loaded with bacteriocin (nisin Z) to acquire broad-spectrum antimicrobial activity. Addition of rhamnolipids into the lipid bilayer exhibited an increase in the encapsulation efficiency of nisin from 47 ± 4% to 88 ± 7%. Scanning electron microscope (SEM) and Zeta-sizer revealed that the surface functionalization with RL increased the size of vesicles from 145 ± 2 nm to 209 ± 4 nm. Whereas, the zeta potential of nisin-loaded RSNVs was −20 ± 0.25 mV as compared to −3.47 ± 0.13 mV for loaded nano-liposomes, indicating higher physical stability of RSNVs. RSNVs not only demonstrated higher antimicrobial activity than liposomes but also enhanced the activity of nisin against Gram-positive and Gram-negative resistant foodborne pathogens including L. monocytogenes, S. aureus, E. coli and P. aeruginosa. Almost 80% reduction in biofilm biomass was observed when treated with nisin-loaded RSNVs due to its improved binding with bacterial surface. Thus, surface-active nanoliposomes (intrinsically active) with higher stability can provide an innovative strategy to control the biofilm-forming food associated pathogens.

Addressing the antibiotic resistance and improving the food safety in food supply chain (farm-to-fork) in Southeast Asia

Antibiotics are the compounds widely used to treat bacterial infections in human and variety of agricultural sectors including livestock farming, plants and crops, and aquaculture. However, rampant and uncontrolled use of antibiotics results in the emergence of resistant bacterial strains. Such resistant strains on the food chain possibly increase the risk of antibiotic resistant foodborne pathogens. Antibiotic resistant bacteria can reach human either directly via the contact with the infected animal or indirectly via the food chain through the consumption of contaminated food. Prevalence of antibiotic resistant bacteria in Southeast Asia region threatens the global public health as this region is regarded as a hotspot of antibiotic resistant bacteria. The risk of development of antibiotic resistance can be reduced only with appropriate regulation and policies. However, the lack of appropriate surveillance systems in this region leads to the absence of reliable national data on the level of antibiotics. To counteract the risk of antibiotic resistance, the World Health Organization (WHO) has published the global action plan on antimicrobial resistance which has been adopted by several countries in Southeast Asia.

Data-Driven Analysis of Antimicrobial Resistance in Foodborne Pathogens from Six States within the US.

Foodborne pathogens cause thousands of illnesses across the US each year. However, these pathogens gain resistance to the antimicrobials that are commonly used to treat them. Typically, antimicrobial resistance is caused by mechanisms encoded by multiple antimicrobial-resistance genes. These are carried through pathogens found in foods such as meats. It is, thus, important to study the genes that are most related to antimicrobial resistance, the pathogens, and the meats carrying antimicrobial-resistance genes. This information can be further used to correlate the antimicrobial-resistance genes found in humans for improving human health. Therefore, we perform the first multivariate statistical analysis of the antimicrobial-resistance gene data provided in the NCBI Pathogen Detection Isolates Browser database, covering six states that are geographically either in close proximity to one another (i.e., Pennsylvania (PA), Maryland (MD), and New York (NY)) or far (i.e., New Mexico (NM), Minnesota (MN), and California (CA)). Hundreds of multidimensional data points were projected onto a two-dimensional space that was specified by the first and second principal components, which were then categorized with a hierarchical clustering approach. It turns out that aadA, aph(3’’), aph(3’’)-Ib, aph(6)-I, aph(6)-Id, bla, blaCMY, tet, tet(A), and sul2 constructed the assembly of ten genes that were most commonly involved in antimicrobial resistance in these six states. While geographically close states like PA, MD and NY share more similar antimicrobial-resistance genes, geographically far states like NM, MN, and CA also contain most of these common antimicrobial-resistance genes. One potential reason for this spread of antimicrobial-resistance genes beyond the geographic limitation is that animal meats like chicken and turkey act as the carriers for the nationwide spread of these genes.

Studies on the Antibacterial Activity and Chemical Composition of Methanol Extract of Cochlospermum tinctorium Root

The aim of study was to evaluate the antibacterial activity of Cochlospermum tinctorium against ten (10) strains of antibiotic resistant food-borne pathogens Staphylococcus aureus and Listeria monocytogene. Ten (10) strains of antibiotic resistant food-borne pathogens Staphylococcus aureus and Listeria monocytogene procured from Microbiology Research Laboratory Usman Danfodiyo University Sokoto. The roots of Cochlospermum tinctorium were collected from the rock side in Dambu Gomo, Zuru Local Government Area of Kebbi State, Nigeria. The roots were washed, air-dried and milled to powder using mortal and pestle and sieved to obtained fine powder. Maceration was used for extraction using methanol as solvent. The antibacterial activity of the plant was determined on Mueller Hinton agar using agar well diffusion method. Minimum concentration (MIC) and minimum inhibitory concentration (MBC) of plant extract was also determined. Thin layer chromatography and column chromatography was employed for separation and fraction of different compounds in the plant extract. The fractions were screened for antibacterial activity and active fractions having high antibacterial activity were subjected Gas Chromatography Mass Spectoscopy (GC-MS) analysis. The result of methanol extraction yield 5.17% extracts. The methanol extract of Cochlospermum tinctorium was effective in inhibiting the isolates at high concentration of 10 mg/mL. The results thin layer chromatography revealed four spots with Rf values 0.02, 0.37, 0.44 and 0.80 respectively. The GC-MS analysis of the active methanol extract of Cochlospermum tinctorium root powder revealed the existence of major peaks 1-(+)-Ascorbic acid 2,6-dihexadecanoate (R.T: 13.666), Diethyl phthalate (R.T: 10.440), Undecyl acetate (R.T: 10.007), 3-tetradecanone (R.T: 9.793), 3-hexadecanone (R.T: 12.427). It therefore concluded that the root of Cochlospermum tinctorium has immense potential to be used in the area of pharmacology as it possess antimicrobial activity against the antibiotic resistant food-borne pathogens, thus could be exploited as alternative antimicrobial drugs.

Biosynthesis of antibacterial compound against multidrug resistant foodborne pathogens by Phomopsis sp. XP-8

Multi-drug resistance of foodborne pathogens has been greatly highlighted in food safety and caused a significant challenge for the development of new antibiotics and safe preservatives. The ethanol extract of Phomopsis sp. XP-8 broth showed significant inhibitory effects on multi-drug resistance of foodborne pathogens. After purification with thin-layer chromatography and liquid chromatographic analysis, the antibacterial compound was identified as methyl quercetin according to FTIR spectrum analysis and ESI-Q-TOF-MS analysis. Via substrate-feeding experiments, the mass flow for the biosynthesis of methyl quercetin was defined as (starting from glucose to phenylalanine): cinnamic acid, p-coumaric acid, quercetin, and methyl quercetin. The study revealed the capability of methyl quercetin to inhibit foodborne multi-drug resistant Escherichia coli, Staphylococcus aureus, and Salmonella shubra, as well as the capability of Phomopsis sp. XP-8 to produce methyl quercetin, showing potential application in food control.