Róbert Herich

Staphylococcus aureus is characterized by substantial genomic diversity, with lineages differing in antimicrobial resistance, virulence-associated determinants, and accessory genetic content. However, genomic data from Ecuador remain comparatively limited. Here, we characterized five clinical S. aureus isolates recovered in Ibarra, Ecuador, using phenotypic antimicrobial susceptibility testing and whole-genome sequencing, and compared them with publicly available Ecuadorian genomes. The isolates represented four sequence types (ST8, ST30, ST72, and ST2625), including four MRSA isolates and one MSSA isolate. Whole-genome analysis identified differences in antimicrobial resistance determinants, virulence-associated genes, and replicons, while phenotypic susceptibility profiles generally corresponded with the detected resistance traits. The Ecuadorian collection showed a diverse population structure, with ST8 predominating. Placement within globally circulating lineages showed that the ST8 isolates clustered with USA300-LV (CA12), the ST30 isolate with G2-Sg2-Pr, and the ST72 isolate with clade B. A focused phylogenomic analysis of ST2625 showed limited genomic divergence among Ecuadorian and international isolates, with broadly similar resistance and virulence-associated profiles. These findings add genomic data from northern Ecuador and illustrate variation in the genetic composition of circulating S. aureus lineages. Continued genomic surveillance across additional geographic settings may help clarify the distribution and diversity of S. aureus in the country.

Background/Objectives: The gut microbiota is fundamental to human health. Probiotics are key interventions for modulating microbial balance, requiring future healthcare professionals to understand these concepts. Evidence evaluating the knowledge, attitudes, and practices (KAP) of medical students in Ecuador is limited. This study assessed these aspects among students in Greater Guayaquil. Methods: A cross-sectional study was conducted at a university in Samborondón between August and November 2025. A previously published questionnaire was used to collect data on microbiota and probiotic knowledge, attitudes, and personal practices. Data were analyzed using descriptive statistics and multivariable regression. Results: Among 382 participants, the mean knowledge score was 22.76 ± 9.1 out of 44 (52.7%). Higher scores were associated with advanced academic standing and prior formal instruction. Significant gaps were observed in probiotic safety and microbiota–drug interactions. Attitudes were positive (median 10/16), with strong support for enhanced training. Probiotic use was common, though uncertainty about product composition and administration persisted. Conclusions: Medical students possess moderate yet uneven knowledge of microbiota and probiotics, alongside positive attitudes. These findings suggest the need for greater emphasis on microbiota science, probiotic safety, and drug interactions within medical curricula.

Public concern over drug resistance has led to governmental regulations banning the use of antibiotics as growth promoters, stimulating interest in developing complementary strategies to maintain animal production, mitigate infections, and enhance muscle characteristics and quality parameters, especially in meat-producing animals. Probiotics are recognized as a potential strategy for improving growth, primarily by promoting intestinal homeostasis. These microorganisms are suggested to modulate gut microbiota, preserving their ecosystem and influencing secondary metabolite production, which can directly or indirectly regulate skeletal muscle metabolism by influencing the expression of key muscle-related genes and the activity of various signaling factors. Several studies have documented the potential benefits of various strains of Bacillus, Enterococcus, and members of the Lactobacillaceae family on muscle characteristics. These studies have shown that probiotics not only modulated myogenic factors but also influenced proteins and enzymes involved in signaling pathways related to carbon metabolism, inflammatory response, mitochondrial dynamics, and antioxidant activity. These effects have been associated with improvements in meat quality parameters and enhanced growth performance. This manuscript seeks to present a brief overview of the impact of probiotic supplementation on muscle health and the quality of meat in broiler chickens.

The implementation of government regulations on antibiotic use, along with the public’s concern for drug resistance, has strengthened interest in developing alternatives not only aimed at preserving animal production but also at reducing the effects of pathogenic infections. Probiotics, in particular, are considered microorganisms that induce health benefits in the host after consumption of adequate amounts; they have been established as a potential strategy for improving growth, especially by stimulating intestinal homeostasis. Probiotics are commonly associated with lactic acid bacteria, and Limosilactobacillus fermentum is a well-studied species recognized for its favorable characteristics, including adhesion to epithelial cells, production of antimicrobial compounds, and activation of receptors that prompt the transcription of immune-associated genes. Recently, this species has been used in animal production. Different studies have shown that the application of L. fermentum strains not only improves the intestinal ecosystem but also reduces the effects caused by potentially pathogenic microorganisms. These studies have also revealed key insights into the mechanisms behind the actions exerted by this probiotic. In this manuscript, we aim to provide a concise overview of the effects of L. fermentum administration on broiler chicken health and performance.

The effect of inorganic zinc and Ascaridia galli infection was studied on MUC1, MUC2 (mucin), sIgA (secretory immunoglobulin A), and metallothionein in the intestines of broilers. Thirty-five-day-old chickens (n = 24), COBB 500 breed, were included in a 14-day experiment. Chickens were divided into 4 groups of 6 chickens each: control ©, Ascaridia galli (AG), Zinc group (Zn), and combined group (AG + Zn). Samples from the intestine for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. Samples from the jejunum for determination of MUC1, MUC2, sIgA, and metallothionein were taken at 7 and 14 days during necropsy. The results demonstrated that 12 days’ administration of inorganic zinc increased production of MUC1 (p < 0.0001) and MUC2 (p < 0.001) in the Ascaridia galli-infected group (Ag + Zn) in comparison to control (C). The beneficial effect of zinc was also revealed in the production of sIgA (p < 0.0001) in the combined group (AG + Zn) at 7 days. The concentration of metallothionein increased mainly in the zinc group (p < 0.01) of first sampling and was upregulated in Zn and AG + Zn groups. The obtained data indicate the use of inorganic zinc as a suitable immunomodulator of intestinal immunity in Ascaridia galli-infected chickens.

Probiotic bacteria, including the Enterococcus faecium strain, can improve intestinal mucosal health by several mechanisms, including modulation of the immune response, as well as by improving the protective function of the epithelial barrier. In this study, we tested the effect of Enterococcus faecium AL41 on the acute phase proteins response (blood), gene expression of selected molecules of mucosal immunity (immunoglobulin A, mucin-2, insulin-like growth factor 2) and mucus production (all parts of the small intestine) in broilers. Eighty broiler chicks were divided into two groups: a control and E. faecium AL41 (birds were inoculated with AL41 for 7 days) group. The whole experiment lasted 11 days. Our results revealed that the administration of E. faecium AL41 had no substantial effect on the concentrations of acute phase proteins, but we recorded a significant increase in β- and γ-globulin fractions at the end of the experiment, which may indicate an improvement in the immune status. A significant prolonged stimulatory effect of E. faecium AL41 on the relative expression of molecules (immunoglobulin A, mucin-2) as well as on the dynamic of mucus production in the chicken intestine was observed. In addition, AL41 significantly reduced the total number of enterococci in the cecum and faeces.

Immune response of day-old chicks infected with Salmonella Enteritidis PT4 and preventive administration of Enterococcus faecium AL41 were studied using hematology and flow cytometry of immunocompetent cells in blood, cecum, bursa and spleen for 11 days, and included 220 animals divided into four groups (n = 55). E. faecium AL41 was administered for 7 days to EF and EFSE groups and on day 4 SE and EFSE groups were infected with Salmonella Enteritidis. Values of monocytes at 4 dpi significantly increased in EFSE and lymphocytes at 7 dpi in EF groups. Blood CD3, CD4, CD8 and IgM lymphocytes improved in EF and EFSE groups and IgA in EF group at 4 dpi. Phagocytic activity of probiotic groups was improved in both samples. Cecal IEL and LPL lymphocytes showed at 7 dpi stimulation of CD3, CD4 and CD8 subpopulations in probiotic groups, especially in EFSE group, IgA IEL and IgA with IgM LPL in EF groups. Bursa Fabricii at 7 dpi presented overstimulation of IgG subpopulation in SE group, spleen CD3 and CD8 in EF and EFSE groups. E. faecium AL41 revealed the protective effect and positive influence on the local and systemic immune response in Salmonella Enteritidis PT4 infected chickens.

Ascaridiosis in poultry results in a reduction in body weight gain, egg production, as well as microelement levels. Infected poultry have higher demands on feed with the addition of essential elements including zinc. The effects of the infection by Ascaridia galli and the supplementation of inorganic zinc on the immune status of broilers were monitored through evaluation of the relative expression of selected genes (interleukins, IFN-γ, and TNF-α) by real-time PCR, haematology parameters by microscopy, and quantitative changes of lamina propria lymphocytes by flow cytometry in day 7 and day 14 of the study. We observed that the enrichment of the diet with inorganic zinc has a positive effect on the relative percentage of CD4+ lamina propria lymphocytes in the jejunum and on heterophil counts in blood. In addition, it was concluded that inorganic zinc has an anti-inflammatory effect (downregulation of TNF-α and IL-17) and activates IgA-producing cells in the jejunum of chicks infected with A. galli.

This research was conducted to investigate if the administration of the probiotic Lactobacillus fermentum could influence body weight, intestinal morphometry and the cecal cytokine response in Campylobacter jejuni-infected chickens. Seventy-two 1-day old COBB 500 male chicks were allocated randomly into four experimental groups. (I) Control group (C), in which chicks were left untreated. (II) LB group, treated with L. fermentum. (III) Cj group, infected with C. jejuni and (IV) coexposure group in which both bacteria were administered. Body weight was registered and then all birds were slaughtered; samples from the small intestine and caecum were collected at 4- and 7-days post infection. The experiment lasted eleven days. Villi height and crypt depth ratios of the duodenum, jejunum and ileum were evaluated using appropriate software, while reverse transcription quantitative PCR (RT-qPCR) was utilized for assessing transcript levels of key cecal inflammatory cytokines (IL-1β, IL-18, IL-17, IL-15, IL13 and IL-4). Campylobacter-infected birds showed lower body weight values than those supplemented with the probiotic; these birds, in turn, proved to be heavier than those reared under control conditions. L. fermentum administration improved morphometrical parameters of the duodenum, jejunum and ileum; in general, villi were larger and crypts deeper than those identified in control conditions. Moreover, the negative effects elicited by C. jejuni were not observed in chickens exposed to the probiotic. Significant differences were also determined with regards to transcript abundance of all evaluated cytokines in the caecum. C. jejuni induced a downregulation of the studied interleukins; however, such a response was heightened by administration of L. fermentum, with an increase rate of transcription that promoted a more effective response to a C. jejuni infection. The effects of experimental treatments proved to vary between sampling points. Conclusively, these results demonstrate that L. fermentum lessens the negative effects elicited by C. jejuni on body weight by alleviating the impact on intestinal morphometry and cecal cytokine response, which ultimately improve chicken growth performance.

Due to the interest in using probiotic bacteria in poultry production, this research was focused on evaluating the effects of Lactobacillus fermentum Biocenol CCM 7514 administration on body weight gain and cytokine gene expression in chickens challenged with Campylobacter jejuni. One-hundred and eight 1-day old COBB 500 broiler chickens were equally assigned to four experimental groups at random. In the control group (C) chicks were left untreated, whereas in groups LB and LBCj a suspension of L. fermentum was administered. A suspension of C. jejuni was subsequently applied to groups Cj and LBCj. Body weight was registered, and the individuals were later slaughtered; cecum samples were collected at 12, 36 and 48 h post-infection (hpi). The entire experiment lasted seven days. Reverse transcription quantitative PCR (RT-qPCR) was used to determine expression levels of IL-1β, IL-15, IL-17, and IL-18 at each time point. Pathogen-infected individuals were observed to weigh significantly less than those fed with the probiotic. Significant differences were also found in transcript abundance; expression of IL-15 was downregulated by the probiotic and upregulated by C. jejuni. The effects of bacterial treatments were time-dependent, as the expression profiles differed at later stages. The present outcomes demonstrate that L. fermentum both reduces the impact of C. jejuni infection on chicken body weight and regulates positively pro-inflammatory cytokine expression, which ultimately increase bird well-being and improves production.