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Resumen del poster presentado en: XIII Reunión del Grupo de Microbiología Molecular de La SEM. Granada, 7-9 septiembre (2022), This work was supported by Grants: THINKINAZUL/2021/027 from ThinkInAzul programme and BIO2017-82244-P; PID2020-113207GB-I00; PID2020-120619RB-I00 of MCIN (Ministerio de Ciencia e Innovación de España) with funding from European Union NextGeneration EU (PRTRC17.I1) and AICO/2020/076 funded by GV (Generalitat Valenciana).

Tuberculosis remains a major health problem worldwide. Drug-resistant and hypervirulent Mycobacterium tuberculosis (Mtb) strains can lead to a hyperinflammatory response and necrotic pathology in hyper-reactive individuals that require adjunctive treatment. Plant-derived substances have been investigated for TB treatment, among which flavonoids stand out. We evaluate the anti-Mtb, anti-inflammatory and cytotoxicity activities of fractions and substances 1, 2 and 3 isolated from Erythrina verna through a bioassay guided fractionation. Seven fractions (1, 3-5 and 7-9) obtained from dichloromethane E. verna extract inhibited NO production (IC50 ≤ 15 μg/mL) with none or poor cytotoxic effect, while the fractions 4 and 5 notably reduced TNF-a production. Fractions 4, 6 and 9 suppressed Mycobacterium growth with MIC50 ≤ 20 μg/mL. Fraction 4 was the most potent due to dual biological activities. Erythratidinone and alpinumisoflavone inhibited the growth of Mtb H37Rv and hypervirulent strain in bacterial cultures (MIC50 ≤ 20 μg/mL), with erythratidinone standing out in reducing intracellular growth of Mtb H37Rv (5.8 ± 1.1 μg/mL). Alpinumisoflavone and erythratidinone were capable of inhibiting NO and TNF-α production besides showing significant inhibitory effects against Mycobacterium tuberculosis strains with low toxicity in macrophages. Both substances are promising for further studies focusing on an anti-TB dual treatment approach.

Tuberculosis remains a major health problem worldwide. Drug-resistant and hypervirulent Mycobacterium tuberculosis (Mtb) strains can lead to a hyperinflammatory response and necrotic pathology in hyper-reactive individuals that require adjunctive treatment. Plant-derived substances have been investigated for TB treatment, among which flavonoids stand out. We evaluate the anti-Mtb, anti-inflammatory and cytotoxicity activities of fractions and substances 1, 2 and 3 isolated from Erythrina verna through a bioassay guided fractionation. Seven fractions (1, 3-5 and 7-9) obtained from dichloromethane E. verna extract inhibited NO production (IC50 ≤ 15 μg/mL) with none or poor cytotoxic effect, while the fractions 4 and 5 notably reduced TNF-a production. Fractions 4, 6 and 9 suppressed Mycobacterium growth with MIC50 ≤ 20 μg/mL. Fraction 4 was the most potent due to dual biological activities. Erythratidinone and alpinumisoflavone inhibited the growth of Mtb H37Rv and hypervirulent strain in bacterial cultures (MIC50 ≤ 20 μg/mL), with erythratidinone standing out in reducing intracellular growth of Mtb H37Rv (5.8 ± 1.1 μg/mL). Alpinumisoflavone and erythratidinone were capable of inhibiting NO and TNF-α production besides showing significant inhibitory effects against Mycobacterium tuberculosis strains with low toxicity in macrophages. Both substances are promising for further studies focusing on an anti-TB dual treatment approach.

Vibrio vulnificus is a pathogen of public health concern that causes either primary septicemia after ingestion of raw shellfish or secondary septicemia after wound exposure to seawater. In consequence, shellfish and seawater are considered its main reservoirs. However, there is one aspect of its biology that is systematically overlooked: its association with fish in its natural environment. This association led in 1975 to the emergence of a zoonotic clade within phylogenetic lineage 2 following successive outbreaks of vibriosis in farmed eels. Although this clade is now worldwide distributed, no new zoonotic clades were subsequently reported. In this work, we have performed phylogenetic, genomic and functional studies to show that other zoonotic clades are in fact present in 4 of the 5 lineages of the species. Further, we associate these clades, most of them previously but incompletely described, with the acquisition of a family of fish virulence plasmids containing genes essential for resistance to the immune system of certain teleosts of interest in aquaculture. Consequently, our results provide several pieces of evidence about the importance of this species as a zoonotic agent linked to fish farms, as well as on the relevance of these artificial environments acting as drivers that accelerate the evolution of the species.

Potentially zoonotic Vibrio vulnificus strains were isolated from vibriosis outbreaks occurring on eastern Mediterranean tilapia farms between 2016 and 2019. In this work, the draft genome sequences of three representative isolates are presented.

Effective treatment approaches for biofilms in endotracheal tubes (ETTs) are lacking. In this study, we evaluated the in vitro effects of five antimicrobials against biofilms formed by Klebsiella pneumoniae in ETTs. K. pneumoniae was added to minimal mucin medium prior to inoculation in microtiter plates containing ETT fragments. Biofilm susceptibility was assessed by crystal violet staining. At 24 h, the antimicrobials significantly reduced biofilm formation. At 48 h, all of the antimicrobial agents exhibited significant reductions in biofilm formation, even at concentrations above the minimum inhibitory concentration (MIC). Tigecycline and fosfomycin showed the greatest inhibition capacity, with good activity at concentrations twofold greater than the MIC. K. pneumoniae exhibited excellent biofilm formation ability, with formation in the first 24 h and significantly reduced antimicrobial activity. These results contribute to the establishment of new antibiotic breakpoints for the adequate management of infections associated with biofilm formation.

Vibrio vulnificus (Vv) is a multi-host pathogenic species currently subdivided into three biotypes (Bts). The three Bts are human-pathogens, but only Bt2 is also a fish-pathogen, an ability that is conferred by a transferable virulence-plasmid (pVvbt2). Here we present a phylogenomic analysis from the core genome of 80 Vv strains belonging to the three Bts recovered from a wide range of geographical and ecological sources. We have identified five well-supported phylogenetic groups or lineages (L). L1 comprises a mixture of clinical and environmental Bt1 strains, most of them involved in human clinical cases related to raw seafood ingestion. L2 is formed by a mixture of Bt1 and Bt2 strains from various sources, including diseased fish, and is related to the aquaculture industry. L3 is also linked to the aquaculture industry and includes Bt3 strains exclusively, mostly related to wound infections or secondary septicemia after farmed-fish handling. Lastly, L4 and L5 include a few strains of Bt1 associated with specific geographical areas. The phylogenetic trees for ChrI and II are not congruent to one another, which suggests that inter-and/or intra-chromosomal rearrangements have been produced along Vv evolution. Further, the phylogenetic trees for each chromosome and the virulence plasmid were also not congruent, which also suggests that pVvbt2 has been acquired independently by different clones, probably in fish farms. From all these clones, the one with zoonotic capabilities (Bt2-Serovar E) has successfully spread worldwide. Based on these results, we propose a new updated classification of the species based on phylogenetic lineages rather than on Bts, as well as the inclusion of all Bt2 strains in a pathovar with the particular ability to cause fish vibriosis, for which we suggest the name "piscis."

BACKGROUND: The increasing use of long-lasting nail aesthetic products has led to a growing number of cases of allergic contact dermatitis (ACD) caused by (meth)acrylates in recent years. OBJECTIVES: To provide information on ACD caused by (meth)acrylates related to nail cosmetic products. METHODS: We retrospectively reviewed files of patients with ACD caused by (meth)acrylates related to nail cosmetic products, who were patch tested between January 2011 and December 2015 in 13 departments of dermatology in Portugal. RESULTS: Two-hundred and thirty cases of ACD caused by (meth)acrylates (55 technicians, 56 consumers, and 119 with mixed exposure) had been documented, mostly as chronic hand eczema (93%). The most common sensitizers were: 2-hydroxyethyl methacrylate (HEMA), which was positive in 90% of the tested patients, 2-hydroxypropyl methacrylate (HPMA), which was positive in 64.1%, and ethyleneglycol dimethacrylate, which was positive in 54.5%. CONCLUSION: HEMA and HPMA were the most frequent positive allergens. HEMA, which identified 90% of cases, can be considered to be a good screening allergen. The high number of cases of ACD caused by (meth)acrylates in nail cosmetic products certainly warrants better preventive measures at the occupational level, and specific regulation in the field of consumer safety. info:eu-repo/semantics/publishedVersion