Determination of MIC, MPC, and MSW of Ilex paraguariensis against non-typhoidal Salmonella with identification of the mechanisms of resistance and pathogenicity factors.

This study investigated the antibacterial activity of the aqueous extract of Ilex paraguariensis against 32 different strains of nontyphoidal Salmonella (NTS) through the determination of the minimum inhibitory concentration (MIC), mutant prevention concentration (MPC), and mutant selection window (MSW) and the detection of virulence genes by multiplex PCR assays. The MIC values of Ilex paraguariensis against Salmonella spp. strains varied between 0.78 mg/ml and 6.25 mg/ml with a MIC90 of 3.12 mg/ml. The highest MPC in this study was 48 mg/ml yielding a mutant selection window of 41.75 mg/ml. The MSW values of the remaining strains varied between 1.56 and 8.87 mg/ml. Genes of pathogenicity detected in Salmonella spp. isolates were most commonly the stn, sdiA, invA, sopB, invH, and sopE genes. The antibacterial activity of yerba mate extract was not affected by the antimicrobial resistance patterns or pathogenicity genes expressed. More work is needed to identify the active antibacterial compound(s) responsible for the antibacterial activity.

Antimicrobial resistance in non-Typhoidal Salmonella from retail poultry meat by antibiotic usage-related production claims - United States, 2008-2017.

Antimicrobial resistance (AMR) in non-typhoidal Salmonella from poultry is a public health concern. Injudicious use of antibiotics in humans and agriculture fuels the emergence of resistance. The objective of this study was to characterize the prevalence, antibiotic susceptibility profiles and genetic resistance mechanisms of Salmonella isolated from US retail poultry meat samples with and without antibiotic-related claims. We reviewed data from 46,937 poultry meat samples collected from 2008 to 2017 through the FDA NARMS retail meat program. Antibiotic usage claims on the poultry packaging were used to categorize the sample as 'conventionally raised' or 'reduced or no antibiotic use'. The results show that the prevalence of Salmonella in conventional poultry samples (8.6%) was higher than reduced or no antibiotic use poultry samples (5.1%). The odds of resistance to three or more antimicrobial classes (multi-drug resistant) were 2.61 times higher for Salmonella isolates from conventional samples, compared to isolates from reduced antibiotic use samples. The frequency of the aminoglycoside resistance gene, strB, and the beta-lactam resistant gene, blaCMY-2, were higher in isolates from conventional meat. This study suggests that conventionally raised poultry meat was more likely to be contaminated with multi-drug resistant Salmonella, and those Salmonella are more likely to carry genes for antibiotics resistance.

Mutagenic potential of medicinal plants evaluated by the Ames Salmonella/microsome assay: A systematic review.

The Ames test has become one of the most commonly used tests to assess the mutagenic potential of medicinal plants since they have several biological activities and thus have been used in traditional medicine and in the pharmaceutical industry as a source of raw materials. Accordingly, this review aims to report previous use of the Ames test to evaluate the mutagenic potential of medicinal plants. A database was constructed by curating literature identified by a search on the electronic databases Medline (via Pubmed), Science Direct, Scopus, and Web of Science from 1975 to April 2020, using the following terms: "genotoxicity tests" OR "mutagenicity tests" OR "Ames test" AND "medicinal plants." From the research, 239 articles were selected, including studies of 478 species distributed across 111 botanical families, with Fabaceae, Asteraceae and Lamiaceae being the most frequent. It was identified that 388 species were non-mutagenic. Of these, 21% (83/388) showed antimutagenic potential, most notable in the Lamiaceae family. The results also indicate that 18% (90/478) of the species were mutagenic, of which 54% were mutagenic in the presence and absence of S9. Strains TA98 and TA100 showed a sensitivity of 93% in detecting plant extracts with mutagenic potential. However, the reliability of many reviewed studies regarding the botanical extracts may be questioned due to technical issues, such as testing being performed only in the presence or absence of S9, use of maximum doses below 5 mg/plate and lack of information on the cytotoxicity of tested doses. These methodological aspects additionally demonstrated that a discussion about the doses used in research on mixtures, such as the ones assessed with botanical extracts and the most sensitive strains employed to detect the mutagenic potential, should be included in a possible update of the guidelines designed by the regulatory agencies.

The phenotypic and molecular characteristics of antimicrobial resistance of Salmonella enterica subsp. enterica serovar Typhimurium in Henan Province, China.

BACKGROUND: Salmonella enterica subsp. enterica serovar Typhimurium infections continue to be a significant public health threat worldwide. The aim of this study was to investigate antibiotic resistance among 147 S. Typhimurium isolates collected from patients in Henan, China from 2006 to 2015. METHODS: 147 S. Typhimurium isolates were collected from March 2006 to November 2015 in Henan Province, China. Antimicrobial susceptibility testing was performed, and the resistant genes of ciprofloxacin, cephalosporins (ceftriaxone and cefoxitin) and azithromycin were detected and sequenced. Clonal relationships were assessed by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). RESULTS: Of the 147 isolates, 91.1% were multidrug resistant (MDR), with 4.1% being resistant to all antibiotic classes tested. Of concern, 13 MDR isolates were co-resistant to the first-line treatments cephalosporins and ciprofloxacin, while three were also resistant to azithromycin. Seven PFGE patterns were identified among the 13 isolates. All of the isolates could be assigned to one of four main groups, with a similarity value of 89%. MLST assigned the 147 isolates into five STs, including two dominant STs (ST19 and ST34). Of the 43 ciprofloxacin-resistant isolates, 39 carried double gyrA mutations (Ser83Phe, Asp87Asn/Tyr/Gly) and a single parC (Ser80Arg) mutation, including 1 isolate with four mutations (gyrA: Ser83Phe, Asp87Gly; parC: Ser80Arg; parE: Ser458Pro). In addition, 12 isolates not only carried mutations in gyrA and parC but also had at least one plasmid-mediated quinolone resistance (PMQR) gene. Among the 32 cephalosporin-resistant isolates, the most common extended-spectrum ß-lactamase (ESBL) gene was blaOXA-1, followed by blaCTX-M, blaTEM-1, and blaCMY-2. Moreover, the mphA gene was identified in 5 of the 15 azithromycin-resistant isolates. Four MDR isolates contained ESBL and PMQR genes, and one of them also carried mphA in addition. CONCLUSION: The high level of antibiotic resistance observed in S. Typhimurium poses a great danger to public health, so continuous surveillance of changes in antibiotic resistance is necessary.

Ethnomedicinal survey and mutagenic studies of plants used in Accra metropolis, Ghana.

ETHNOPHARMACOLOGICAL RELEVANCE: Majority of people living in Ghana and many other developing countries rely on traditional medicinal plants for their primary healthcare. These plants are used either alone or in combination to manage a wide range of ailments. However, most of these plants have not been investigated for their mutagenic effects. AIM OF THE STUDY: This study, therefore aimed at evaluating the mutagenic activity of the most frequently used medicinal plants amongst Ghanaians living within the Accra metropolis, Ghana. MATERIALS AND METHODS: Validated questionnaires were administered to 53 herbalists and herbal medicines dealers in the Makola, Madina and Nima communities. Plants that were identified as being frequently used were investigated for their mutagenicity using the Ames test. RESULTS: A total of 110 medicinal plants belonging to 53 families were identified as most frequently used plants in the study sites. These are used to treat various ailments including gastric ulcer, fever, malaria, male impotence, diabetes, typhoid, high blood pressure and candidiasis. Thirteen samples (52%) showed moderate to high mutagenicity in the TA 100 bacterial strain before and after metabolism with rat liver enzyme. CONCLUSIONS: The study showed that over half of the frequently used medicinal plants showed moderate to high mutagenicity before and after metabolism at the concentration of a 100 µg/mL. This may have implications for the safety of those who use them to manage diseases. These findings will suggest the need for an in-depth study of the mutagenic potentials of plants commonly used by indigenous people and more especially for those exhibiting high mutagenicity in this study.

Optimization of Salmonella detection in garlic, onion, cinnamon, red chili pepper powders and green tea.

Salmonella is the causative agent of many outbreaks related to spice consumption. However, because of the antimicrobial properties of various spices which hinders recovery and detection, Salmonella detection in spices remains a challenge. The objective of this study was to optimize an enrichment broth for Salmonella growth in different spices and tea, in order to maintain an adequate pH and decrease the antimicrobial effects of spices during Salmonella enrichment and subsequent detection. Salmonella contaminated spice and tea dried samples were prepared and the detection of Salmonella was assessed using the developed broth and automated DNA extraction and RT-PCR. Double strength Buffered Peptone Water (BPW) was used to maintain pH, and L-cysteine and DL-serine were added to the broth to reduce the effects of antimicrobial compounds in spices. The modified enrichment broth allowed the growth of Salmonella from each spice sample. Sample to broth ratios varied from 1:9 (garlic powder, chili peppers and tea), to 1:20 (cinnamon). The pH value of each enrichment varied but remained above 4.8. The addition of L-cysteine (30 mmol/L) allowed Salmonella recovery and growth in garlic and onion samples and the addition of DL-serine (11.23 mmol/L) allowed the recovery and growth in cinnamon. The results indicated that Salmonella detection was achieved in <24 h in the modified (BPW + L-cysteine and DL-serine) enrichment broth followed by detection by RT-PCR. This protocol could allow for a more rapid, robust, and sensitive enrichment method for Salmonella in spices.

Mutagenicity emission factors of canola oil and waste vegetable oil biodiesel: Comparison to soy biodiesel.

Canola (or rapeseed) oil and waste vegetable oil (WVO) are used commonly to make biodiesel fuels composed completely from these oils (B100) or as blends with petroleum diesel (B0). However, no studies have reported the mutagenic potencies of the particulate matter with diameter ≤2.5 µm (PM2.5) or the mutagenicity emission factors, such as revertants/MJthermal (rev/MJth) for these biodiesel emissions. Using strains TA98 and TA100 with the Salmonella (Ames) mutagenicity assay, we determined these metrics for organic extracts of PM2.5 of emissions from biodiesel containing 5% soy oil (soy B5); 5, 20, 50, and 100% canola (canola B5, B20, B50, B100), and 100% waste vegetable oil (WVO B100). The mutagenic potencies (rev/mg PM2.5) of the canola B100 and WVO B100 emissions were generally greater than those of B0, whereas the mutagenicity emission factors (rev/MJth, rev/kg fuel, and rev/m3) were less, reflecting the lower PM emissions of the biodiesels relative to B0. Nearly all the rev/mg PM2.5 and rev/MJth values were greater in TA98 with S9 than without S9, indicating a relatively greater role for polycyclic aromatic hydrocarbons, which require S9, than nitroarenes, which do not. In TA100 -S9, the rev/mg PM2.5 and rev/MJth for the biodiesels were generally ≥ to those of B0, indicating that most of these biodiesels produced more direct-acting, base-substitution mutagenic activity than did B0. For B100 biodiesels and petroleum diesel, the rev/MJth in TA98 + S9 ranked: petroleum diesel > canola > WVO > soy. The diesel emissions generally had rev/MJth values orders of magnitude higher than those of large utility-scale combustors (natural gas, coal, oil, or wood) but orders of magnitude lower than those of inefficient open burning (e.g., residential wood fireplaces). These comparative data of the potential health effects of a variety of biodiesel fuels will help inform the life-cycle assessment and use of biodiesel fuels.

BioID screen of Salmonella type 3 secreted effectors reveals host factors involved in vacuole positioning and stability during infection.

Many bacterial pathogens express virulence proteins that are translocated into host cells (herein referred to as effectors), where they can interact with target proteins to manipulate host cell processes. These effector-host protein interactions are often dynamic and transient in nature, making them difficult to identify using traditional interaction-based methods. Here, we performed a systematic comparison between proximity-dependent biotin labelling (BioID) and immunoprecipitation coupled with mass spectrometry to investigate a series of Salmonella type 3 secreted effectors that manipulate host intracellular trafficking (SifA, PipB2, SseF, SseG and SopD2). Using BioID, we identified 632 candidate interactions with 381 unique human proteins, collectively enriched for roles in vesicular trafficking, cytoskeleton components and transport activities. From the subset of proteins exclusively identified by BioID, we report that SifA interacts with BLOC-2, a protein complex that regulates dynein motor activity. We demonstrate that the BLOC-2 complex is necessary for SifA-mediated positioning of Salmonella-containing vacuoles, and affects stability of the vacuoles during infection. Our study provides insight into the coordinated activities of Salmonella type 3 secreted effectors and demonstrates the utility of BioID as a powerful, complementary tool to characterize effector-host protein interactions.

Process risk model for Salmonella and ground chicken.

AIMS: To develop a process risk model (PRM) for evaluating the safety of individual lots of ground chicken (GC) contaminated with Salmonella (Salm). METHODS AND RESULTS: Data for prevalence, number and serotype of Salm were collected with 25 g samples of GC using a combination of methods (whole sample enrichment, quantitative polymerase chain reaction, cultural isolation and serotyping). These data were used to develop a predictive model for Salm contamination of GC as a function of serving size from 25 to 300 g. This model was combined with a model for thermal inactivation of Salm in GC and a dose-response model for Salm to develop a PRM in Excel that was simulated with NeuralTools and @Risk. Of 100, 25 g samples of GC examined, 19 tested positive for Salm. Three serotypes were isolated: Infantis (n = 13), Enteritidis (n = 5) and Typhimurium (n = 1). The number of Salm ranged from 0 to 2·56 log with a median of 0·93 log per 25 g of GC. The PRM predicted that Salm prevalence would increase (P < 0·05) from 19 to 57% to 82 to 93% as serving size increased from 25 to 100 g to 200 to 300 g. However, the total number of Salm in a 100-kg lot of GC and total severity of illness (TSI) were not affected (P> 0·05) by serving size. The PRM was also used to evaluate effects of serving size distribution, cooking, food consumption behaviour, consumer demographics and Salmonella virulence on TSI. CONCLUSIONS: How a lot of GC is partitioned and consumed does not affect TSI. Scenario analysis demonstrated that the PRM can integrate prevalence, number and serotype data for Salm with consumer handling, consumption and demographics data to identify safe and unsafe lots of GC for improved food safety and public health. SIGNIFICANCE AND IMPACT OF THE STUDY: Process-risk models like the one developed in this study represent a new, holistic approach to food safety that holds great promise for improving public health and reducing food recalls.

Tolerance to benzalkonium chloride and antimicrobial activity of Butia odorata Barb. Rodr. extract in Salmonella spp. isolates from food and food environments.

Salmonellosis, caused by the consumption of contaminated foods, is a major health problem worldwide. The aims of this study were to assess the susceptibility of Salmonella spp. isolates to benzalkonium chloride (BC) disinfectant and the antimicrobial activity of Butia odorata Barb. Rodr. extract against the same isolates from food and food environments. Moreover, phenotypic and genotypic resistance profiles, the presence of virulence genes and biofilm forming ability were determined. The minimum inhibitory concentration (MIC) of B. odorata extract against Salmonella spp. ranged from 10 to >19 mg.mL-1. Resistance to ampicillin, streptomycin, nalidixic acid, sulfonamide, trimethoprim/sulfamethoxazole, trimethoprim, tetracycline, and chloramphenicol was observed. In addition, multidrug resistance was observed in seven isolates (26.92%). The MIC of BC ranged from 32 to 64 mg.L-1, higher concentrations in comparison with wild-type MICs, and therefore were considered tolerant. Several resistance genes were detected, of which the most common were aadA, qacEΔ1, blaTEM, int1, sul1, and tetA. All isolates carried at least one virulence gene and produced biofilms on stainless steel surfaces at 10 and 22 °C. On the other hand, the B. odorata extract showed activity against Salmonella spp., and it has the potential to be used as a natural antimicrobial to control this important foodborne pathogen, despite its virulence potential and antimicrobial resistance profile.

Effect of symbiotic supplementation on fecal calprotectin levels and lactic acid bacteria, Bifidobacteria, Escherichia coli and Salmonella DNA in patients with cervical cancer.

BACKGROUND: patients with cervical cancer (CC) receiving chemotherapy and radiotherapy have several gastrointestinal adverse effects. OBJECTIVE: to evaluate the effect of dietary symbiotic supplementation on fecal calprotectin (FCP), bacterial DNA levels, and gastrointestinal adverse effects in patients with CC. METHODS: clinical, controlled, randomized, double-blind trial. Patients consumed symbiotics or placebo three times a day for seven weeks. FCP was assessed by Elisa method. DNA from probiotic and pathogenic bacteria were determined by quantitative real-time polymerase chain reaction. Diarrheal evacuations were evaluated with the Bristol stool form scale and nausea and vomiting were measured using the scale of the National Institute of Cancerology of the United States. RESULTS: after a seven-week treatment, FCP concentration was lower in the symbiotic group compared to the control group (p < 0.001). Stool consistency in the placebo and symbiotic groups was similar at baseline. A significant improvement in stool consistency was obtained in both groups at the end of the intervention (p < 0.001). The concentrations and total proportions of the probiotic and pathogenic bacteria were similar in both groups. Nausea significantly diminished in both groups (p < 0.001) at the end of the trial. Furthermore, the symbiotic group had a statistically significant decrease in the frequency and intensity of vomiting when compared to the control group (p < 0.001). CONCLUSIONS: the symbiotic treatment decreases significantly the FCP levels and the frequency and intensity of vomiting in patients with CC.

Multipurpose efficacy of the lyophilized cell-free supernatant of Salmonella bongori isolated from the freshwater fish, Devario aequipinnatus: toxicity against microbial pathogens and mosquito vectors.

Presently, the discovery of effective drugs and pesticides from eco-friendly biological sources is an important challenge in the field of life sciences. The present research was aimed for standardizing an innovative approach in the evaluation of the biological potentiality of the metabolites of fish-associated bacteria. We have identified 17 skin-associated bacteria from the freshwater fish, giant danio, Devario aquipinnatus. They were screened through biofilm forming and extracellular enzyme producing ability. The results of preliminary antibacterial evaluation of the bacterial supernatants underlined the importance of three potential strains (BH8, BH10 and BH11) for further applied research. Hence, such strains were subsequently subjected to a novel extraction procedure to overcome the difficulties found in polar solvents mixed with the supernatant. The lyophilized cell-free supernatant (LCFS) of 3 isolates were individually extracted by using methanol. During the testing of LCFS's methanolic extract (LCFS-ME) of 3 isolates, only the extract of BH11-strain exhibited potent inhibitory activity against the pathogenic bacteria and fungi. Furthermore, the larvicidal and mosquitocidal assays on the filariasis vector, Culex quinquefasciatus also showed its potent toxicity on both the adults and developmental instars of mosquito. Through molecular and phylogenetic analyses, the BH11 strain was identified as Salmonella bongori (KR350635). The present finding emphasized that the S. bongori could be an important novel source of effective antimicrobials and mosquitocidal agents.

Antimicrobial Effect of Garlic (Allium sativum) and Thyme (Zataria multiflora Boiss) Extracts on Some Food Borne Pathogens and Their Effect on Virulence Gene Expression.

The incrementing scope of pathogenic resistance to antibiotics has encouraged the search for antivirulence natural extracts. Therefore, our study designed to demonstrate the antimicrobial activity of an aqueous-garlic and thyme oil extracts against Gram-positive (Staphylococcus aureus) and Gram-negative (Salmonella spp.) bacteria by evaluating the influence of sub-inhibitory concentrations on the expression of the most critical virulence genes of the tested isolates. The antibacterial potential of both herbs was checked by the agar well diffusion method and minimum inhibitory concentration (MIC) assay. Interestingly, all isolates were inhibited by both extracts up to 50% concentration. Also, the MIC values of garlic extract (0.125-1µg/ml) against Salmonella isolates were lower than the values of thyme extract (0.5- 8µg/ml). But in S. aureus isolates, the MIC values of thyme extract (0.25- 2µg/ml) were the lowermost. Conventional PCR investigated that all S. aureus isolates carried the hlg (hemolysin) and icaA (intracellular adhesion) genes, but only six Salmonella isolates (three S. typhimurium and one each of S. kentucky, S. anatum, and S. lagos) had both the sopB (Salmonella outer protein B) and mgtC (membrane protein) genes. Real-time RT-PCR assays were performed to evaluate the extract's effect on the virulence genes. The thyme-oil extract has significantly repressed S. aureus virulence genes expression more than aqueous-garlic extract, which later one has effectively more than thyme-oil extract in downregulating the Salmonella virulence genes. In conclusion, garlic and thyme extracts can be used not only as a flavor, but also as potential antimicrobial agents against Gram-positive and negative bacteria.

Fluoroquinolone resistance in Salmonella: insights by whole-genome sequencing.

Fluoroquinolone (FQ)-resistant Salmonella spp. were listed by the WHO in 2017 as priority pathogens for which new antibiotics were urgently needed. The overall global burden of Salmonella infections is high, but differs per region. Whereas typhoid fever is most prevalent in South and South-East Asia, non-typhoidal salmonellosis is prevalent across the globe and associated with a mild gastroenteritis. By contrast, invasive non-typhoidal Salmonella cause bloodstream infections associated with high mortality, particularly in sub-Saharan Africa. Most Salmonella strains from clinical sources are resistant to first-line antibiotics, with FQs now being the antibiotic of choice for treatment of invasive Salmonella infections. However, FQ resistance is increasingly being reported in Salmonella, and multiple molecular mechanisms are already described. Whole-genome sequencing (WGS) is becoming more frequently used to analyse bacterial genomes for antibiotic-resistance markers, and to understand the phylogeny of bacteria in relation to their antibiotic-resistance profiles. This mini-review provides an overview of FQ resistance in Salmonella, guided by WGS studies that demonstrate that WGS is a valuable tool for global surveillance.

PART I: FIGHTING CANCER WITH DEADLY BACTERIA.

A 200-year-old observation might provide a new way to eliminate tumors by infecting cancer patients with bacteria. Kristie Nybo explores a new approach that could transform cancer treatment.

PART II: BREAKTHROUGHS IN TUMOR-SEEKING BACTERIA.

Newly engineered bacterial strains propel an immune-mediated cancer therapy toward clinical applications. Hannah Martin Lawrenz reports on the latest developments.

Genotoxic and cytotoxic potential of Alternanthera Bettzickiana, an important ethno-medicinal plant.

The present study was carried out to investigate the mutagenic and cytotoxic potential of n-hexane and aqueous-methanolic whole plant extracts of Alternanthera bettzickiana. Aqueous-methanolic and n-hexane extracts of Alternanthera bettzickiana extracts were assessed for the mutagenic potential with Salmonella tester strains TA-100 and TA-102 in the presence and absence of the rodent enzyme activation system and cytotoxic potential was assessed by MTT assay. Aqueous-methanolic extract showed the presence of saponins, tannins, terpenoids, flavonoids and glycosides. However n-hexane extract revealed the presence of tannins and terpenoids only. It was found that a concentration as low as 15mg/mL of both extracts was more mutagenic to the TA 102 tester strain than TA-100. Hexane whole plant extract of Altenanthera bettzickiana was more mutagenic than aqueous-methanolic extract considering revertant colonies of TA 100 strain. Aqueous-methanolic and n-hexane whole plant extracts of Altenanthera bettzickiana showed higher mutagenic potential in the presence of the enzyme activation system. Mutagenicity of aqueous-methanolic extract increased with an enzyme activation system in case of TA 100 whereas mutagenicity of n-hexane extract decreased in the presence of the enzyme activation system with TA 100 and TA 102 strains. Aqueous-methanolic and n-Hexane whole plant extracts of Alternanthera bettzickiana showed an IC-50 of 493 and 456 µg/mL in BHK-21 cells respectively. It can be concluded that Altenanthera bettzickiana exhibited mutagenic activity in a bacterial reverse mutation assay with and without enzyme activation systems. However, it showed limited cytotoxicity to BHK-21 cells.

2D-NMR investigation and in vitro evaluation of antioxidant, antigenotoxic and estrogenic/antiestrogenic activities of strawberry grape.

Strawberry grape is considered beneficial due to its extensive phytochemical properties. To expand the knowledge about the chemical constituents and the biological activities of the whole plant, 2D-NMR investigation has been carried out on pulp, peel, seeds, stalks and leaves. Catechin and epicatechin were identified as the main constituents of the seed extract, quercetin and ferulic acid were detected in the leaves and malvidin and cyanidin glucopyranoside in the peels. The leaf, stalk and seed extracts were found to be very rich in phytochemicals and were tested for their ability to reduce the mutagenicity and genotoxicity of standard agents via Salmonella mutagenicity assay and SOS chromotest, respectively. Moreover, the estrogen/antiestrogen-like activity was evaluated on the MCF-7 estrogen-responsive cells. Seed and stalk extracts had an elevated antimutagenic/antigenotoxic activity. Stalk extracts highly reduced the proliferative effect of natural estrogen, 17ß-estradiol.