Clonal relationship, virulence genes, and antimicrobial resistance of Morganella morganii isolated from community-acquired infections and hospitalized patients: a neglected opportunistic pathogen.

Morganella morganii is a bacterium belonging to the normal intestinal microbiota and the environment; however, in immunocompromised individuals, this bacterium can become an opportunistic pathogen, causing a series of diseases, both in hospitals and in the community, being urinary tract infections more prevalent. Therefore, the objective of this study was to evaluate the prevalence, virulence profile, and resistance to antimicrobials and the clonal relationship of isolates of urinary tract infections (UTI) caused by M. morganii, both in the hospital environment and in the community of the municipality of Londrina-PR, in southern Brazil, in order to better understand the mechanisms for the establishment of the disease caused by this bacterium. Our study showed that M. morganii presents a variety of virulence factors in the studied isolates. Hospital strains showed a higher prevalence for the virulence genes zapA, iutA, and fimH, while community strains showed a higher prevalence for the ireA and iutA genes. Hospital isolates showed greater resistance compared to community isolates, as well as a higher prevalence of multidrug-resistant (MDR) and extended-spectrum beta lactamase (ESBL)-producing isolates. Several M. morganii isolates from both sources showed high genetic similarity. The most prevalent plasmid incompatibility groups detected were FIB and I1, regardless of the isolation source. Thus, M. morganii isolates can accumulate virulence factors and antimicrobial resistance, making them a neglected opportunistic pathogen.

Essential oil of oregano (Origanum vulgare L.) reduces infection and proliferation of Toxoplasma gondii in BeWo cells with induction of autophagy and death of tachyzoites through a mechanism similar to necrosis.

Toxoplasmosis poses a global health threat, ranging from asymptomatic cases to severe, potentially fatal manifestations, especially in immunocompromised individuals and congenital transmission. Prior research suggests that oregano essential oil (OEO) exhibits diverse biological effects, including antiparasitic activity against Toxoplasma gondii. Given concerns about current treatments, exploring new compounds is important. This study was to assess the toxicity of OEO on BeWo cells and T. gondii tachyzoites, as well as to evaluate its effectiveness in in vitro infection models and determine its direct action on free tachyzoites. OEO toxicity on BeWo cells and T. gondii tachyzoites was assessed by MTT and trypan blue methods, determining cytotoxic concentration (CC50), inhibitory concentration (IC50), and selectivity index (SI). Infection and proliferation indices were analyzed. Direct assessments of the parasite included reactive oxygen species (ROS) levels, mitochondrial membrane potential, necrosis, and apoptosis, as well as electron microscopy. Oregano oil exhibited low cytotoxicity on BeWo cells (CC50: 114.8 µg/mL ± 0.01) and reduced parasite viability (IC50 12.5 ± 0.06 µg/mL), demonstrating 9.18 times greater selectivity for parasites than BeWo cells. OEO treatment significantly decreased intracellular proliferation in infected cells by 84% after 24 h with 50 µg/mL. Mechanistic investigations revealed increased ROS levels, mitochondrial depolarization, and lipid droplet formation, linked to autophagy induction and plasma membrane permeabilization. These alterations, observed through electron microscopy, suggested a necrotic process confirmed by propidium iodide labeling. OEO treatment demonstrated anti-T. gondii action through cellular and metabolic change while maintaining low toxicity to trophoblastic cells.

Multiple potentially toxic elements in urban gardens from a Brazilian industrialized city.

Urban agriculture should be promoted as long as the food produced is safe for consumption. Located in the metropolitan region of São Paulo-Brazil, Santo André has intense industrial activities and more recently an increasing stimulus to urban gardening. One of the potential risks associated to this activity is the presence of potentially toxic elements (PTEs). In this study, the concentration of PTEs (As, Ba, Cd, Co, Cu, Cr, Ni, Mo, Pb, Sb, Se, V and Zn) was evaluated by soil (n = 85) and soil amendments (n = 19) in urban gardens from this municipality. Only barium was above regulatory limits in agricultural soil ranging from 20 to 112 mg kg-1. Geochemical indexes (Igeo, Cf and Er) revealed moderate to severe pollution for As, Ba, Cr, Cu, Pb Se and Zn, especialy in Capuava petrochemical complex gardens. A multivariate statistical approach discriminated Capuava gardens from the others and correlated As, Cr and V as main factors of pollution. However, carcinogenic and non-carcinogenic risks were below the acceptable range for regulatory purposes of 10-6-10-4 for adults. Soil amendments were identified as a possible source of contamination for Ba, Zn and Pb which ranged from 37 to 4137 mg kg-1, 20 to 701 mg kg-1 and 0.7 to 73 mg kg-1, respectively. The results also indicated the presence of six pathogenic bacteria in these amendments. Besides that, the occurrence of antimicrobial resistance for Shigella, Enterobacter and Citrobacter isolates suggests that soil management practices improvement is necessary.

Multidrug-resistant Escherichia coli strains isolated from swine manure biofertilizer in Brazil.

Escherichia coli is one of the key bacteria responsible for a variety of diseases in humans and livestock-associated infections around the globe. It is the leading cause of mortality in neonatal and weaned piglets in pig husbandry, causing diarrhea and significant harm to the industry. Furthermore, the frequent and intensive use of antimicrobials for the prevention of diseases, particularly gastrointestinal diseases, may promote the selection of multidrug-resistant (MDR) strains. These resistant genotypes can be transmitted through the excrement of animals, including swine. It is common practice to use porcine manure processed by biodigesters as fertilizer. This study aimed to examine the antimicrobial susceptibility, the presence of virulence genes frequently associated with pathotypes of intestinal pathogenic E. coli (InPEC), and antimicrobial resistance genes (ARGs) of 28 E. coli isolates collected from swine manure fertilizers. In addition, the enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) technique was used to investigate the genetic relationship among the strains. Using disk diffusion, the antimicrobial susceptibility profiles of the strains were determined. Using polymerase chain reaction (PCR), 14 distinct virulence genes associated with the most prevalent diarrhea and intestinal pathogenic E. coli (DEC/InPEC) and five ARGs were analyzed. All isolates tested positive for multidrug resistance. There was no detection of any of the 14 virulence genes associated with InPECs, indicating the presence of an avirulent commensal microbiota. Molecular classification by ERIC-PCR revealed that the majority of isolates (27 isolates) coalesced into a larger cluster with a genetic similarity of 47.7%; only one strain did not cluster in this cluster, indicating a high level of genetic diversity among the analyzed isolates. Thus, it is of the utmost importance to conduct epidemiological surveillance of animal breeding facilities in order to determine their microbiota and formulate plans to reduce the use of antimicrobials and improve animal welfare.

Biogenic silver nanoparticles and cinnamaldehyde as an effective sanitizer for fresh sweet grape tomatoes.

This study evaluated the antibacterial activity of cinnamaldehyde (CIN) and biogenic silver nanoparticles (BioAgNP), alone and in combination, against Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus in vitro. Their sanitation activities on fresh sweet grape tomatoes were also evaluated. CIN and BioAgNP inhibited the growth of the tested bacteria, and at low concentrations, their combinations presented a synergistic effect. In the sanitization of fresh sweet grape tomatoes, CIN (156 µg/mL) combined with BioAgNP (31.25 µM) at subinhibitory concentrations inhibited the growth of E. coli after only 5 min of contact. Exposed samples showed no growth of E. coli during their shelf life. The combination of these compounds did not change significantly (p > 0.05) the physicochemical properties of sweet grape tomatoes and showed that CIN combined with BioAgNP could represent an effective method for decontaminating fruits and vegetables. This combination has great potential for application in the prevention of foodborne diseases.

Development of a multifunctional and self-preserving cosmetic formulation using sophorolipids and palmarosa essential oil against acne-causing bacteria.

AIMS: The objective of this study was to evaluate the antibacterial effect of sophorolipids in combination with palmarosa essential oil and to develop a cosmetic formulation against acne-causing bacteria. METHODS AND RESULTS: The antibacterial activity of sophorolipids, palmarosa oil and their combined effect was evaluated by broth microdilution and checkerboard methods. Antioxidant activity was determined by the DPPH method. The results showed that the compounds presented antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis. The combination of sophorolipid and palmarosa oil resulted in synergistic and additive interaction reducing the concentration needed for the effectiveness against S. aureus and S. epidermidis, to 98.4% and 50%, respectively. The compounds interaction showed an additive effect for antioxidant activity. The cosmetic formulation without any chemical preservative presents antibacterial activity against S. aureus, S. epidermidis and Cutibacterium acnes. The pH values and organoleptic characteristics of formulations remained stable under all conditions tested. CONCLUSIONS: The association of sophorolipids and palmarosa oil resulted in a self-preserving cosmetic formulation with great stability, and effective antioxidant and antibacterial activities against acne-causing micro-organisms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed the development of an effective multifunctional cosmetic formulation with natural preservatives to treat acne vulgaris and other skin infections.

Thermosensitive gel based on cellulose derivative for topical delivery of propolis in acne treatment.

Thermosensitive bioadhesive formulations can display increased retention time, skin permeation, and improve the topical therapy of many drugs. Acne is an inflammatory process triggered by several factors like the proliferation of the bacteria Propionibacterium acnes. Aiming for a new alternative treatment with a natural source, propolis displays great potential due to its antibiotic, anti-inflammatory, and healing properties. This study describes the development of bioadhesive thermoresponsive platform with cellulose derivatives and poloxamer 407 for propolis skin delivery. Propolis ethanolic extract (PES) was added to the formulations with sodium carboxymethylcellulose (CMC) or hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (Polox). The formulations were characterized as rheology, bioadhesion, and mechanical analysis. The selected formulations were investigated as in vitro propolis release, cytotoxicity, ex vivo skin permeation by Fourier Transform Infrared Photoacoustic Spectroscopy, and the activity against P. acnes. Formulations showed suitable sol-gel transition temperature, shear-thinning behavior, and texture profile. CMC presence decreased the cohesiveness and adhesiveness of formulations. Polox/HPMC/PES system displayed less cytotoxicity, modified propolis release governed by anomalous transport, skin permeation, and activity against P. acnes. These results indicate important advantages in the topical treatment of acne and suggest a potential formulation for clinical evaluation.

Quorum sensing system: Target to control the spread of bacterial infections.

Quorum Sensing (QS) systems regulate the gene expression of different types of virulence factors in accordance with the cell population density. A literature search was performed, including electronic databases such as MEDLINE/PubMed, SciELO, and LILACS, as well as other databases not indexed, such as Google Scholar. The search was conducted between July 2018 and April 2019, through online research. Antimicrobial resistance is one of the biggest threats to global health and the dissemination of resistant microbes in the environment is a major public health problem. Therefore, it is important to develop new therapies to control the spread of resistant bacteria to humans. Thus, interference in the chemical signal (autoinducers) of the QS system has been postulated as a good alternative, technically known as "Quorum Quenching" or QS inhibitors. Inhibition of QS signaling is not intended to kill the microorganism, but to block the expression of the target genes, making the cells less virulent and more vulnerable to host immune response. Anti-virulence therapy by agents that interfere with this system in pathogenic bacteria is a well-studied strategy, including medicinal plants and their bioactive constituents, and presents good prospects. This review aims to provide an overview of the QS system in bacteria and describe the main inhibitors of the system.

Violacein@Biogenic Ag system: synergistic antibacterial activity against Staphylococcus aureus.

OBJECTIVES: To examine the synergistic antibacterial activity of violacein and silver nanoparticles (AgNPs) against ATCC bacteria, Staphylococcus aureus, Escherichia coli and two bacteria isolated from bovine mastitis. METHODS: Violacein from Chromobacterium violaceum and biogenic AgNPs from Fusarium oxysporum were evaluated in antimicrobial tests. RESULTS: E. coli isolates were not inhibited by violacein at concentrations up to 400 µM and they showed sensitivity for AgNPs between 62.5 and 250 µM. Staphylococcus aureus showed sensitivity to violacein with MIC of 200 µM, and the MIC with AgNPs between 250 µM and 125 µM. It was also tested the association between the two compounds through a concentration gradient and was observed the reduction of the MIC in the combination for both strains. CONCLUSION: The bactericidal effect of violacein against S. aureus was better when combined with AgNPs (synergistic).

Characterization of non-O157 Shiga toxin-producing Escherichia coli (STEC) obtained from feces of sheep in Brazil.

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens and may induce severe diarrheagenic diseases in humans and other animals. Non-O157 STEC have been emerging as important pathogens causing outbreaks worldwide. Bacterial resistance to antimicrobials has become a global public health problem, which involves different ecological spheres, including animals. This study aimed to characterize the resistance to antimicrobials, plasmids and virulence, as well as the serotypes and phylogenetic groups in E. coli isolated from sheep in Brazil. A total of 57 isolates were obtained and showed different antimicrobial resistance profiles. Nineteen isolates presented acquired antimicrobial resistance genes (ARGs) (blaCTX-M-Gp9, qnrB, qnrS, oqxB, oqxA, tetA, tetB, tetC, sul1 and sul2) and plasmid families (F, FIA, FIB, I1, K, HI1 and ColE-like). The stx1, stx2 and ehxA virulence genes were detected by PCR, being 50 isolates (87.7%) classified as STEC. A great diversity of serotypes was detected, being O176:HNM the most predominant. Phylogenetic group E was the most prevalent, followed by B1, A and B2. To the best of our knowledge, this is the first report in the world of blaCTX-M-Gp9 (O75, O114, O100, O128ac and O176 serogroups), qnrB and oqxB genes in non-O157 STEC in healthy sheep. The results obtained in the present study call attention to the monitoring of antimicrobial-resistant non-O157 STEC harboring acquired ARGs worldwide and indicate a zoonotic risk due to the profile of virulence, resistance and serotype found.

Avian extraintestinal Escherichia coli exhibits enterotoxigenic-like activity in the in vivo rabbit ligated ileal loop assay.

Avian pathogenic Escherichia coli (APEC) strains harbor a number of virulence genes and cause extraintestinal diseases, such as septicemia, swollen-head syndrome, salpingitis, and omphalitis in poultry. APEC strains are not known to cause intestinal diseases. Herein, for the first time, it is reported that APEC strains were able to induce an enterotoxigenic-like effect in rabbit ligated ileal loops. Strain SEPT362 caused cell detachment of the intestinal villi, which also showed a flattened and wilted appearance, but the integrity of the tight junctions was maintained. Additionally, this strain did not adhere to enterocytes in vivo, although adhesin encoding genes ( fimH, csgA, lpfA2-3, and ECP) were present while other lpfA types, sfa, afa, papC, and ral genes were not. This enterotoxigenic-like activity was conserved after thermal treatment of the supernatant at 65°C but not at 100°C. Moreover, experiments based on filtering with different molecular weight cut-off (MWCO) pore sizes demonstrated that the component associated with the observed biological effect has a molecular weight >100 kDa. Blast search and polymerase chain reaction assays for known E. coli virulence factors showed that strain SEPT362 harbors the gene encoding for the toxin EAST-1 and the serine protease autotransporter (SPATE) Tsh, but is negative for genes encoding for the toxins LT-I, STh, STp, Stx1, Stx2, CNF-1, CNF-2, CDT and the SPATEs Sat, Pic, Vat, SigA, SepA, EatA, EspP, or EspC. A cloned copy of the tsh gene in E. coli K-12 was also tested and was shown to have an enterotoxic effect. These results suggest that APEC might induce fluid accumulation in the rabbit gut. The Tsh autotransporter seems to be one of the factors associated with this phenotype.

Phenotypic and genotypic characterizations of bacteria isolated from the respiratory microbiota of healthy turkeys with potential for probiotic composition.

Desirable characteristics of Staphylococcus sp., Streptococcus sp., Bacillus sp., Klebsiella sp., Escherichia coli, and Pseudomonas pseudoalcaligenes isolated from the trachea of healthy turkeys were evaluated as probiotic candidates in the search for new alternatives to solve antimicrobial resistance issues in poultry. In current study phenotypic and genotypic capacity to produce bacteriocin-like substances, efficacy to inhibit the growth of avian pathogens, susceptibility to antimicrobials of bacteria isolated from the respiratory microbiota of healthy turkeys, and the presence of virulence-associated genes (VAGs) predictors of Avian Pathogenic Escherichia coli (APEC) were evaluated. Nine E. coli and one Klebsiella sp. strains produced bacteriocin-like substances, and all harbored the cvaA gene. Some strains also showed antagonistic activity against APEC. Multidrug-resistant profile was found in 54% of the strains. Six strains of bacteriocin-like substances producing E. coli also harbored 3-5 VAGs. The study showed that two bacterial genuses (Klebsiella sp. and E. coli) present desirable probiotic characteristics. Our results identified strains with potential for poultry's respiratory probiotic.

Comparative analysis of effectiveness for phage cocktail development against multiple Salmonella serovars and its biofilm control activity.

Foodborne diseases are a major challenge in the global food industry, especially those caused by multidrug-resistant (MDR) bacteria. Bacteria capable of biofilm formation, in addition to MDR strains, reduce the treatment efficacy, posing a significant threat to bacterial control. Bacteriophages, which are viruses that infect and kill bacteria, are considered a promising alternative in combating MDR bacteria, both in human medicine and animal production. Phage cocktails, comprising multiple phages, are commonly employed to broaden the host range and prevent or delay the development of phage resistance. There are numerous techniques and protocols available to evaluate the lytic activity of bacteriophages, with the most commonly used methods being Spot Test Assays, Efficiency of Plating (EOP), and infection assays in liquid culture. However, there is currently no standardization for which analyses should be employed and the possible differences among them in order to precisely determine the host range of phages and the composition of a cocktail. A preliminary selection using the Spot Test Assay resulted in four phages for subsequent evaluation against a panel of 36 Salmonella isolates of numerous serovars. Comparing EOP and infection assays in liquid culture revealed that EOP could underestimate the lytic activity of phages, directly influencing phage cocktail development. Moreover, the phage cocktail containing the four selected phages was able to control or remove biofilms formed by 66% (23/35) of the isolates, including those exhibiting low susceptibility to phages, according to EOP. Phages were characterized genomically, revealing the absence of genes associated with antibiotic resistance, virulence factors, or integrases. According to confocal laser scanning microscopy analysis, the biofilm maturation of one Salmonella isolate, which exhibited high susceptibility to phages in liquid culture and 96-well plates biofilm viability assays but had low values for EOP, was found to be inhibited and controlled by the phage cocktail. These observations indicate that phages could control and remove Salmonella biofilms throughout their growth and maturation process, despite their low EOP values. Moreover, using infection assays in liquid culture enables a more precise study of phage interactions for cocktail design timelessly and effortlessly. Hence, integrating strategies and techniques to comprehensively assess the host range and lytic activity of bacteriophages under different conditions can demonstrate more accurately the antibacterial potential of phage cocktails.

Cellulose Hydrogel with Hyaluronic Acid and Silver Nanoparticles: Sustained-Release Formulation with Antibacterial Properties against Pseudomonas aeruginosa.

Pathogenic bacteria resistant to conventional antibiotics represent a global challenge and justify the need for new antimicrobials capable of combating bacterial multidrug resistance. This study describes the development of a topical hydrogel in a formulation composed of cellulose, hyaluronic acid (HA), and silver nanoparticles (AgNPs) against strains of Pseudomonas aeruginosa. AgNPs as an antimicrobial agent were synthesized by a new method based on green chemistry, using arginine as a reducing agent and potassium hydroxide as a carrier. Scanning electron microscopy showed the formation of a composite between cellulose and HA in a three-dimensional network of cellulose fibrils, with thickening of the fibrils and filling of spaces by HA with the presence of pores. Ultraviolet-visible spectroscopy (UV-vis) and particle size distribution for dynamic light scattering (DLS) confirmed the formation of AgNPs with peak absorption at ~430 nm and 57.88 nm. AgNPs dispersion showed a minimum inhibitory concentration (MIC) of 1.5 µg/mL. The time-kill assay showed that after 3 h of exposure to the hydrogel containing AgNPs, there were no viable cells, corresponding to a bactericidal efficacy of 99.999% in the 95% confidence level. We obtained a hydrogel that is easy to apply, with sustained release and bactericidal properties against strains of Pseudomonas aeruginosa at low concentrations of the agent.

Epidemiology and characterization of Providencia stuartii isolated from hospitalized patients in southern Brazil: a possible emerging pathogen.

This study aimed to characterize the virulence factors and antimicrobial resistance of Providencia stuartii , an opportunistic pathogen that causes human infections. We examined 45 isolates of P. stuartii both genotypically and phenotypically by studying their adherence to HeLa cells, biofilm formation, cytotoxicity and antimicrobial resistance, and analysed their genomes for putative virulence and resistance genes. This study found that most isolates possessed multiple virulence genes, including fimA, mrkA, fptA, iutA, ireA and hlyA, and were cytotoxic to Vero cells. All the isolates were resistant to amoxicillin plus clavulanic acid, levofloxacin and sulfamethoxazole plus trimethoprim, and most were resistant to ceftriaxone and cefepime. All isolates harboured extended-spectrum beta-lactamase coding genes such as bla CTX-M-2 and 23/45(51.11 %) of them also harboured bla CTX-M-9. The gene KPC-2 (carbapenemase) was detected in 8/45(17.77 %) isolates. This study also found clonality among the isolates, indicating the possible spread of the pathogen among patients at the hospital. These results have significant clinical and epidemiological implications and emphasize the importance of a continued understanding of the virulence and antimicrobial resistance of this pathogen for the prevention and treatment of future infections.

Prevalence of Antimicrobial Resistance and Clonal Relationship in ESBL/AmpC-Producing Proteus mirabilis Isolated from Meat Products and Community-Acquired Urinary Tract Infection (UTI-CA) in Southern Brazil.

The present study aimed to evaluate the prevalence of antimicrobial resistance and clonal relationships in Proteus mirabilis isolated from chicken meat, beef, pork, and community-acquired urinary tract infections (UTI-CA). Chicken meat isolates showed the highest multidrug resistance (MDR), followed by those from pork and UTI-CA, whereas beef had relatively few MDR strains. All sources had strains that carried blaCTX-M-65, whereas blaCTX-M-2 and blaCMY-2 were only detected in chicken meat and UTI-CA isolates. This indicates that chicken meat should be considered an important risk factor for the spread of P. mirabilis carrying ESBL and AmpC. Furthermore, ESBL/AmpC producing strains were resistant to a greater number of antimicrobials and possessed more resistance genes than non-producing strains. In addition, the antimicrobial resistance genes qnrD, aac(6')-Ib-cr, sul1, sul2, fosA3, cmlA, and floR were also found. Molecular typing showed a genetic similarity between chicken meat and UTI-CA isolates, including some strains with 100% similarity, indicating that chicken can be a source of P. mirabilis causing UTI-CA. It was concluded that meat, especially chicken meat, can be an important source of dissemination of multidrug-resistant P. mirabilis in the community.

Hydrogel-Containing Biogenic Silver Nanoparticles: Antibacterial Action, Evaluation of Wound Healing, and Bioaccumulation in Wistar Rats.

Wound infections are feared complications due to their potential to increase healthcare costs and cause mortality since multidrug-resistant bacteria reduce treatment options. This study reports the development of a carbomer hydrogel containing biogenic silver nanoparticles (bioAgNPs) and its effectiveness in wound treatment. This hydrogel showed in vitro bactericidal activity after 2 h, according to the time-kill assay. It also reduced bacterial contamination in rat wounds without impairing their healing since the hydrogel hydrophilic groups provided hydration for the injured skin. The high number of inflammatory cells in the first days of the skin lesion and the greater degree of neovascularization one week after wound onset showed that the healing process occurred normally. Furthermore, the hydrogel-containing bioAgNPs did not cause toxic silver accumulation in the organs and blood of the rats. This study developed a bioAgNP hydrogel for the treatment of wounds; it has a potent antimicrobial action without interfering with cicatrization or causing silver bioaccumulation. This formulation is effective against bacteria that commonly cause wound infections, such as Pseudomonas aeruginosa and Staphylococcus aureus, and for which new antimicrobials are urgently needed, according to the World Health Organization's warning.

Resistance and Virulence Surveillance in Escherichia coli Isolated from Commercial Meat Samples: A One Health Approach.

Escherichia coli is a key indicator of food hygiene, and its monitoring in meat samples points to the potential presence of antimicrobial-resistant strains capable of causing infections in humans, encompassing resistance profiles categorized as serious threats by the Centers for Disease Control and Prevention (CDC), such as Extended-Spectrum Beta-Lactamase (ESBL)-a problem with consequences for animal, human, and environmental health. The objective of the present work was to isolate and characterize ESBL-producing E. coli strains from poultry, pork, and beef meat samples, with a characterization of their virulence and antimicrobial resistance profiles. A total of 450 meat samples (150 chicken, 150 beef, and 150 pork) were obtained from supermarkets and subsequently cultured in medium supplemented with cefotaxime. The isolated colonies were characterized biochemically, followed by antibiogram testing using the disk diffusion technique. Further classification involved biofilm formation and the presence of antimicrobial resistance genes (blaCTX-M, AmpC-type, mcr-1, and fosA3), and virulence genes (eaeA, st, bfpA, lt, stx1, stx2, aggR, iss, ompT, hlyF, iutA, iroN, fyuA, cvaC, and hylA). Statistical analysis was performed via the likelihood-ratio test. In total, 168 strains were obtained, with 73% originating from chicken, 22% from pork, and 17% from beef samples. Notably, strains exhibited greater resistance to tetracycline (51%), ciprofloxacin (46%), and fosfomycin (38%), apart from ß-lactams. The detection of antimicrobial resistance in food-isolated strains is noteworthy, underscoring the significance of antimicrobial resistance as a global concern. More than 90% of the strains were biofilm producers, and strains carrying many ExPEC genes were more likely to be biofilm formers (OR 2.42), which increases the problem since the microorganisms have a greater chance of environment persistence and genetic exchange. Regarding molecular characterization, bovine samples showed a higher prevalence of blaCTX-M-1 (OR 6.52), while chicken strains were more likely to carry the fosA3 gene (OR 2.43, CI 1.17-5.05) and presented between 6 to 8 ExPEC genes (OR 2.5, CI 1.33-5.01) compared to other meat samples. Concerning diarrheagenic E. coli genes, two strains harbored eae. It is important to highlight these strains, as they exhibited both biofilm-forming capacities and multidrug resistance (MDR), potentially enabling colonization in diverse environments and causing infections. In conclusion, this study underscores the presence of ß-lactamase-producing E. coli strains, mainly in poultry samples, compared to beef and pork samples. Furthermore, all meat sample strains exhibited many virulence-associated extraintestinal genes, with some strains harboring diarrheagenic E. coli (DEC) genes.

Synergistic Antileishmanial Effect of Oregano Essential Oil and Silver Nanoparticles: Mechanisms of Action on Leishmania amazonensis.

American tegumentary leishmaniasis, a zoonotic disease caused by the Leishmania genus, poses significant challenges in treatment, including administration difficulty, low efficacy, and parasite resistance. Novel compounds or associations offer alternative therapies, and natural products such as oregano essential oil (OEO), extracted from Origanum vulgare, have been extensively researched due to biological effects, including antibacterial, antifungal, and antiparasitic properties. Silver nanoparticles (AgNp), a nanomaterial with compelling antimicrobial and antiparasitic activity, have been shown to exhibit potent leishmanicidal properties. We evaluated the in vitro effect of OEO and AgNp-Bio association on L. amazonensis and the death mechanisms of the parasite involved. Our results demonstrated a synergistic antileishmanial effect of OEO + AgNp on promastigote forms and L. amazonensis-infected macrophages, which induced morphological and ultrastructural changes in promastigotes. Subsequently, we investigated the mechanisms underlying parasite death and showed an increase in NO, ROS, mitochondrial depolarization, accumulation of lipid-storage bodies, autophagic vacuoles, phosphatidylserine exposure, and damage to the plasma membrane. Moreover, the association resulted in a reduction in the percentage of infected cells and the number of amastigotes per macrophage. In conclusion, our findings establish that OEO + AgNp elicits a late apoptosis-like mechanism to combat promastigote forms and promotes ROS and NO production in infected macrophages to target intracellular amastigote forms.

Biogenic silver nanoparticle exhibits schistosomicidal activity in vitro and reduces the parasitic burden in experimental schistosomiasis mansoni.

Schistosomiasis is a neglected tropical parasitic disease that affects millions of people, being the second most prevalent parasitic disease worldwide. The current treatment has limited effectiveness, drug-resistant strains, and is not effective in different stages of the disease. This study investigated the antischistosomal activity of biogenic silver nanoparticles (Bio-AgNp) against Schistosoma mansoni. Bio-AgNp presented direct schistosomicidal activity on newly transformed schistosomula causing plasma membrane permeabilization. In S. mansoni adult worms, reduced the viability and affected the motility, increasing oxidative stress parameters, and inducing plasma membrane permeabilization, loss of mitochondrial membrane potential, lipid bodies accumulation, and autophagic vacuoles formation. During the experimental schistosomiasis mansoni model, Bio AgNp restored body weight, reduced hepatosplenomegaly, and decrease the number of eggs and worms in feces and liver tissue. The treatment also ameliorates liver damage and reduces macrophage and neutrophil infiltrates. A reduction in count and size was evaluated in the granulomas, as well as a change to an exudative-proliferative phase, with a local increase of IFN-γ. Together our results showed that Bio-AgNp is a promising therapeutic candidate for studies of new therapeutic strategies against schistosomiasis.