Importancia de los Centros Nacionales de Gripe en la vigilancia de virus aviares de alta patogenicidad. El momento para One-Healthes ahora / Importance of National Influenza Centers in the surveillance of highly pathogenic avian viruses. The time for One-Health is now

Desde el año 1996 el subtipo de gripe aviar de alta patogenicidad A(H5N1) ha estado casi de forma ininterrumpida causando brotes en aves salvajes y domésticas, además de casos en seres humanos con una mortalidad cercana al 50%. Sin embargo, los años de mayor circulación han sido precisamente los años posteriores a la pandemia de COVID-19, en los que se han registrado diversos casos en humanos en lugares donde nunca antes habían aparecido, además de múltiples casos en mamíferos salvajes, domésticos y peri domésticos, que entrañan cierta preocupación por el riesgo que puede suponer para el salto del virus al ser humano través de cadenas de transmisión de mayor o menor extensión. El brote actual de A(H5N1) nos muestra que el concepto One-Health debe estar más vivo que nunca para aunar esfuerzos entre profesionales de diferentes sectores de la sanidad humana, animal y medio ambiental para evitar o minimizar estos riesgos, de tal forma que los laboratorios de referencia como los Centros Nacionales de Gripe dispongan de los medios humanos y materiales para ofrecerinformación rápida y relevante en el menor tiempo posible antes emergencias de este tipo. Las herramientas de diagnóstico y seguimiento que se deben utilizar en estos casos deben estar disponibles para cualquier eventualidad, y llegar más allá de los datos básicos debe ser una premisa indispensable para poder hacer un seguimiento pormenorizado que sirva para acotar brotes, limitar la difusión de la enfermedad, y ayudar al diseño de futuras vacunas pandémicas frente a virus aviares. (AU)

Since 1996, the highly pathogenic avian influenza subtype A(H5N1) has been causing almost uninterrupted outbreaks in wild and domestic birds, as well as cases in humans with a mortality rate close to 50%. However, the years of greatest circulation have been precisely the years following the COVID-19 pandemic, in which several cases have been recorded in humans in places where they had never appeared before, in addition to multiple cases in wild, domestic and peri-domestic mammals, which raise some concern about the risk that the virus may jump to humans through chains of transmission of greater or lesser extent. The current outbreak of A(H5N1) shows us that the One-Health concept should be more alive than ever to join efforts between professionals from different sectors of human, animal and environmental health to avoid or minimize these risks, so that reference laboratories such as the National Influenza Centers have the human and material resources to provide rapid and relevant information in the shortest possible time before emergencies of this type. The diagnostic and monitoring tools to be used in these cases must be available for any eventuality, and going beyond the basic data must be an indispensable premise to be able to carry out a detailed monitoring that serves to limit outbreaks, limit the spread of the disease, and help in the design of future pandemic vaccines against avian viruses. (AU)

K+ homeostasis is important for survival of Acinetobacter baumannii ATCC 19606 in the nosocomial environment / La homeostasis del K+ es importante para la supervivencia de Acinetobacter baumannii ATCC 19606 en el ambiente nosocomial

Pathogenic bacteria have developed several mechanisms to thrive within the hostile environment of the human host, but it is often disregarded that their survival outside this niche is crucial for their successful transmission. Acinetobacter baumannii is very well adapted to both the human host and the hospital environment. The latter is facilitated by multifactorial mechanisms including its outstanding ability to survive on dry surfaces, its high metabolic diversity, and, of course, its remarkable osmotic resistance. As a first response to changing osmolarities, bacteria accumulate K+ in high amount to counterbalance the external ionic strength. Here, we addressed whether K+ uptake is involved in the challenges imposed by the harsh conditions outside its host and how K+ import influences the antibiotic resistance of A. baumannii. For this purpose, we used a strain lacking all major K+ importer ∆kup∆trk∆kdp. Survival of this mutant was strongly impaired under nutrient limitation in comparison to the wild type. Furthermore, we found that not only the resistance against copper but also against the disinfectant chlorhexidine was reduced in the triple mutant compared to the wild type. Finally, we revealed that the triple mutant is highly susceptible to a broad range of antibiotics and antimicrobial peptides. By studying mutants, in which the K+ transporter were deleted individually, we provide evidence that this effect is a consequence of the altered K+ uptake machinery. Conclusively, this study provides supporting information on the relevance of K+ homeostasis in the adaptation of A. baumannii to the nosocomial environment.(AU)

Uropathogenic bacteria and deductive genomics towards antimicrobial resistance, virulence, and potential drug targets / Bacterias uropatógenas y genómica deductiva hacia la resistencia, virulencia y posibles objetivos farmacológicos a los antimicrobianos

Urinary tract infections (UTIs) are among the most prevalent bacterial infections affecting people in inpatient and outpatient settings. The current study aimed to sequence the genome of uropathogenic Escherichia coli strain CUI-B1 resourced from a woman having uncomplicated cystitis and pyelonephritis. Followed by deductive genomics towards potential drug targets using E. coli strain CUI-B1, strain O25b: H4-ST131, Proteus mirabilis strain HI4320, Klebsiella pneumoniae strain 1721, and Staphylococcus saprophyticus strain ATCC 15305 uropathogenic strains. Comparative genome analysis revealed that genes related to the survival of E. coli, P. mirabilis, K. pneumoniae, and S. saprophyticus, such as genes of metal-requiring proteins, defense-associated genes, and genes associated with general physiology, were found to be highly conserved in the genomes including strain CUI-B1. However, the genes responsible for virulence and drug resistance, mainly those that are involved in bacterial secretion, fimbriae, adherence, and colonization, were found in various genomic regions and varied from one species to another or within the same species. Based on the genome sequence, virulence, and antimicrobial-resistant gene dataset, the subtractive proteomics approach revealed 22 proteins mapped to the pathogen’s unique pathways and among them, entB, clbH, chuV, and ybtS were supposed to be potential drug targets and the single drug could be utilized for all above-mentioned strains. These results may provide the foundation for the optimal target for future discovery of drugs for E. coli-, P. mirabilis-, K. pneumoniae-, and S. saprophyticus-based infections and could be investigated further to employ in personalized drug development.(AU)

Characterization and pathogenicity of multidrug-resistant coagulase-negative Staphylococci isolates in chickens / Caracterización y patogenicidad de aislados de estafilococos coagulasa negativos multirresistentes en pollos

The pathogenic potential of vancomycin and methicillin-resistant coagulase-negative Staphylococci (VMRCoNS) on Egyptian poultry farms has received little attention. Therefore, this study aims to study the prevalence of CoNS in imported poultry flocks and commercial poultry farms, evaluate the presence of virulence and antibiotic resistance genes (sea, seb, sec, sed, see, and mecA), and assess their pathogenicity in broiler chicks. Seven species were identified among 25 isolates, such as 8 S. gallinarum, 5 S. saprophyticus, 5 S. chromogens, 3 S. warneri, 2 S. hominis, 1 S. caprae, and 1 S. epidermidis. All isolates were resistant to clindamycin, doxycycline, vancomycin, methicillin, rifampicin, and penicillin. The mecA gene was confirmed in 14 isolates, while the sed gene was revealed in seven isolates. Commercial 1-day-old Ross broiler chicks were divided into eight groups of three replicates (10 birds/group): group Ӏ was negative control; groups (П, Ш, IV, V, VI, VII, and VIII) were subcutaneously inoculated with 108 CFUml−1 of S. hominis, S. caprae, S. epidermidis, S. gallinarum, S. chromogens, S. warneri, and S. saprophyticus, respectively. Groups VIII and V had mortality rates of 100% and 20%, respectively, with no evidence of mortalities in the other groups. The highest re-isolation of CoNS species was recorded in groups VII, VIII, and V. Postmortem and histopathological examination revealed the common presence of polyserositis in the internal organs, and hepatic and myocardial necrosis in groups IV, V, and VI. These findings revealed the pathogenic potential of CoNS, so special attention must be directed toward their public health impact.(AU)

Virulence, antimicrobial resistance, and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae in a hospital in Shijiazhuang City from China / Virulencia, resistencia a los antimicrobianos y características moleculares de Klebsiella pneumoniae resistente a carbapenémicos en un hospital de la ciudad de Shijiazhuang de China

Carbapenem-resistant Klebsiella pneumoniae (CRKP), as one of the most common drug-resistant bacteria threatening human health, is hyper-resistant to multiple antimicrobial drugs and carbapenems, which can be dealt with only limited clinical treatment options. This study described the epidemiological characteristics of CRKP in this tertiary care hospital from 2016 to 2020. Specimen sources included blood, sputum, alveolar lavage fluid, puncture fluid, secretions from a burn wound, and urine. Among the 87 carbapenem-resistant strains, ST11 was the predominant isolate, followed by ST15, ST273, ST340, and ST626. These STs were in broad agreement with the STs defined by pulsed-field gel electrophoresis clustering analysis in discriminating clusters of related strains. Most CRKP isolates contained the blaKPC-2 gene, some isolates carried the blaOXA-1, blaNDM-1, and blaNDM-5 genes, and the isolates carrying carbapenem resistance genes were more resistant to the antimicrobials of β-lactams, carbapenems, macrolides, and fluoroquinolone. The OmpK35 and OmpK37 genes were detected in all CRKP strains, and the Ompk36 gene was detected in some CRKP strains. All detected OmpK37 had 4 mutant sites, and OmpK36 had 11 mutant sites, while no mutant sites were found in OmpK35. More than half of the CRKP strains contained the OqxA and OqxB efflux pump genes. The virulence genes were most commonly combined with urea-wabG-fimH-entB-ybtS-uge-ycf. Only one CRKP isolate was detected with the K54 podoconjugate serotype. This study elucidated the clinical epidemiological features and molecular typing of CRKP, and grasped the distribution of drug-resistant genotypes, podocyte serotypes, and virulence genes of CRKP, providing some guidance for the subsequent treatment of CRKP infection.(AU)

The Tol-Pal system of Acinetobacter baumannii is important for cell morphology, antibiotic resistance and virulence / El sistema Tol-Pal de Acinetobacter baumannii es importante para la morfología celular, la resistencia a los antibióticos y la virulencia

Acinetobacter baumannii is an opportunistic human pathogen that has become a global threat to healthcare institutions. This Gram-negative bacterium is one of the most successful human pathogens worldwide and responsible for hospital-acquired infections. This is due to its outstanding potential to adapt to very different environments, to persist in the human host and most important, its ability to develop multidrug resistance. Our combined approach of genomic and phenotypic analyses led to the identification of the envelope spanning Tol-Pal system in A. baumannii. We found that the deletion of the tolQ, tolR, tolA, tolB, and pal genes affects cell morphology and increases antibiotic sensitivity, such as the ∆tol-pal mutant exhibits a significantly increased gentamicin and bacitracin sensitivity. Furthermore, Galleria mellonella caterpillar killing assays revealed that the ∆tol-pal mutant exhibits a decreased killing phenotype. Taken together, our findings suggest that the Tol-Pal system is important for cell morphology, antibiotic resistance, and virulence of A. baumannii.(AU)

Prevalence and antimicrobial resistance of food safety related Vibrio species in inland saline water shrimp culture farms / Prevalencia y resistencia a los antimicrobianos de especies de Vibrio relacionadas con la inocuidad de los alimentos en granjas de cultivo de camarones de aguas saladas continentales

This study evaluated the potential pathogenicity and antimicrobial resistance (AMR) of Vibrio species isolated from inland saline shrimp culture farms. Out of 200 Vibrio isolates obtained from 166 shrimp/water samples, 105 isolates were identified as V. parahaemolyticus and 31 isolates were identified as V. alginolyticus and V. cholerae, respectively. During PCR screening of virulence-associated genes, the presence of the tlh gene was confirmed in 70 and 19 isolates of V. parahaemolyticus and V. alginolyticus, respectively. Besides, 10 isolates of V. parahaemolyticus were also found positive for trh gene. During antibiotic susceptibility testing (AST), very high resistance to cefotaxime (93.0%), amoxiclav (90.3%), ampicillin (88.2%), and ceftazidime (73.7%) was observed in all Vibrio species. Multiple antibiotic resistance (MAR) index values of Vibrio isolates ranged from 0.00 to 0.75, with 90.1% of isolates showing resistance to ≥ 3 antibiotics. The AST and MAR patterns did not significantly vary sample-wise or Vibrio species-wise. During the minimum inhibitory concentration (MIC) testing of various antibiotics against Vibrio isolates, the highest MIC values were recorded for amoxiclav followed by kanamycin. These results indicated that multi-drug resistant Vibrio species could act as the reservoirs of antibiotic resistance genes in the shrimp culture environment. The limited host range of 12 previously isolated V. parahaemolyticus phages against V. parahaemolyticus isolates from this study indicated that multiple strains of V. parahaemolyticus were prevalent in inland saline shrimp culture farms. The findings of the current study emphasize that routine monitoring of emerging aquaculture areas is critical for AMR pathogen risk assessment.(AU)

Characterization of kefir yeasts with antifungal capacity against Aspergillus species / Caracterización de levaduras de kéfir con capacidad antifúngica frente a especies de Aspergillus

Kefir is a fermented probiotic drink obtained by placing kefir granules in a suitable substrate. The kefir granules are a consortium of bacteria and yeasts embedded in a exopolysaccharide matrix. The aim of this research was the isolation and identification of yeasts from kefir of different origin, the evaluation of their antifungal capacity against Aspergillus spp., and the characterization of virulence related traits. Using RFLP of ITS1/ITS4 region, D1/D2 region sequencing, and RAPD techniques, 20 kefir isolates were identified as Geotrichum candidum, Pichia kudriavzevii, Pichia membranifaciens, Saccharomyces cerevisiae, and Candida ethanolica. Their antifungal capacity was evaluated by their conidia germination reduction, which allowed the selection of eight isolates with high to moderate conidia germination reduction against Aspergillus flavus and Aspergillus parasiticus. Furthermore, these selected isolates showed growth inhibition on contact in the dual culture assay for both Aspergillus species and 3 of them—belonging to S. cerevisiae and P. kudriavzevii species—generated volatile organic compounds which significantly affected the growth of both fungi. For the evaluation of virulence-related traits, growth at high temperatures, enzymatic activities, and the adhesion to Caco-2 cells were analyzed. The isolates did not present more than one positive virulence-related trait simultaneously. In particular, it is important to highlight that the adhesion capacity to the model of intestinal barrier was extremely low for all of them. According to the results obtained, further studies would be of interest for the possible use of these promising yeasts as biocontrol agents against fungi in food.(AU)

Robinsoniella peoriensis: an emerging pathogen with few virulence factors / Robinsoniella peoriensis: un patógeno emergente con pocos factores de virulencia

Robinsoniella peoriensis is a Gram-positive bacterium which is anaerobic, spore-forming, and non-motile. It was initially isolated and characterized from feces and swine manure. Strains of this species have since been identified from different mammalian and non-mammalian gastrointestinal tracts. Strains have also been isolated from a variety of human infections, such as bacteremia, bone infections, and skin structures. R. peoriensis has recently been reported as causative for pyometra, which could result in death in the absence of sufficient antimicrobial treatment. However, to the author’s knowledge, there has not been a single virulence factor identified. A major challenge of modern medicine is the failure of conventional procedures to characterize the capability of an emerging pathogen to cause disease. The goal of this study is to initially characterize the pathogenicity of this bacterium using a pathogenomics approach.(AU)

Antimicrobial resistance, virulence factors, and genotypes of Pseudomonas aeruginosa clinical isolates from Gorgan, northern Iran / Resistencia antimicrobiana, factores de virulencia y genotipos de aislamientos clínicos de Pseudomonas aeruginosa de Gorgan, norte de Irán

Pseudomonas aeruginosa is an important nosocomial pathogen with a capacity of resistance to multiple antibiotics and production of various extracellular and cell-associated virulence factors that clearly contribute to its pathogenicity. The objective of this study was to investigate the antibiotic susceptibility, virulence factors, and clonal relationship among clinical isolates of P. aeruginosa. Different clinical specimens from hospitalized patients were investigated for P. aeruginosa. Susceptibility of the isolates was evaluated by disc diffusion and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute (CLSI) guideline. A total of 97 P. aeruginosa isolates were recovered from clinical specimens. The percentage of isolates resistant to antimicrobials was imipenem 25.77%, meropenem 15.46%, gentamicin 16.49%, tobramycin 15.46%, amikacin 16.49%, ciprofloxacin 20.61%, levofloxacin 24.74, ceftazidime 20.61%, piperacillin 15.46%, piperacillin/tazobactam 12.37%, colistin 9.27%, and polymyxin B 11.34%. Of isolates, 87.62% possessed β-hemolytic activity, 78.35% lecithinase, 59.8% elastase, 37.11% DNase, and 28.86% twitching motility. The frequency of virulence genes in isolates was lasB 82.47%, plcH 82.47%, exoA 58.76%, exoS 56.7%, and pilA 10.3%. ERIC-PCR typing clustered P. aeruginosa isolates to 19 common types (CT1-CT19) containing isolates from different hospitals and 43 single types (ST1-ST43). Colistin and polymyxin B were the most effective agents against the majority of P. aeruginosa isolates, emphasizing the effort to maintain their antibacterial activity as last-line therapy. The frequency of some virulence factors and genes was noticeably high, which is alarming. In addition, more effective strategies and surveillance are necessary to confine and prevent the inter-hospital and/or intra-hospital dissemination of P. aeruginosa between therapeutic centers.(AU)

Circulating tumor DNA tracking in patients with pancreatic cancer using next-generation sequencing / Evaluación de DNA circulante tumoral en paciente con Cáncer de páncreas empleando secuenciación de nueva generación

Background: Pancreatic cancer remains one of the most devastating malignancies due to the absence of techniques for early diagnosis and the lack of target therapeutic options for advanced disease. Next Generation Sequencing (NGS) generates high throughput and valuable genetic information when evaluating circulating tumor DNA (ctDNA); however clinical utility of liquid biopsy in pancreatic cancer has not been demonstrated yet. The aim of this study was to evaluate whether results from a Next Generation Sequencing panel on plasma samples from pancreatic cancer patients could have a clinical significance. Methods: From December 2016 to January 2020, plasma samples from 27 patients with pancreatic ductal adenocarcinoma at two different tertiary Spanish Hospitals underwent ctDNA testing using a commercial NGS panel of 65 genes. Clinical data were available for these patients. VarsSome Clinical software was used to analyse NGS data and establish pathogenicity. Results: Evaluable NGS results were obtained in 18 out of the 27 plasma samples. Somatic pathogenic mutations were found mainly in KRAS, BRCA2, FLT3 and HNF1A, genes. Pathogenic mutations were detected in 50% of plasma samples from patient diagnosed at stages III-IV samples. FLT3 mutations were observed in 22.22% of samples which constitute a novel result in the field. Conclusions: Liquid biopsy using NGS is a valuable tool but still not sensitive or specific enough to provide clinical utility in pancreatic cancer patients.(AU)

Introducción: El cáncer de páncreas es uno de los cánceres más devastadores debido a la falta de métodos que permitan un diagnóstico temprano y la ausencia de opciones terapéuticas en enfermedad avanzada. La técnica de secuenciación de nueva generación o Next Generation Sequencing (NGS) proporciona importantes resultados de alto rendimiento de información genética en muestras de DNA circulante tumoral (ctDNA); sin embargo, la utilidad clínica de la biopsia líquida en cáncer de páncreas no ha sido demostrado todavía. El objetivo de este estudio fue evaluar si los resultados de un panel de secuenciación de nueva generación en muestras de plasma de pacientes con cáncer de páncreas podría tener un significado clínico. Métodos: Empleando un panel comercial de NGS con 65 genes se evaluaron 27 muestras de plasma de pacientes con cáncer de páncreas recogidas entre diciembre del 2016 y enero del 2020 en 2 hospitales españoles. En el estudio se disponía de datos clínicos correspondientes a los pacientes. Se empleó el software VarSome Clinical para analizar resultados y establecer patogenicidad de las variantes. Resultados: Se obtuvieron resultados evaluables en 18 de las 27 muestras de plasma. Se encontraron mutaciones patogénicas en los genes KRAS, BRCA2, FLT3 y HNF1A. El 50% de los pacientes diagnosticados en estadios ii-iv presentaron alteraciones patogénicas en plasma. Se observaron mutaciones en FLT3 en el 22,22% de las muestras, lo cual es un resultado novedoso. Conclusiones: La NGS en biopsia líquida es una herramienta valiosa pero todavía no sensible ni específica para proporcionar utilidad clínica en pacientes con cáncer de páncreas.(AU)

Adaptive strategies of uropathogenic Escherichia coli CFT073: from growth in lab media to virulence during host cell adhesion / Estrategias adaptativas de Escherichia coli CFT073 uropatógena: desde el crecimiento en medios de laboratorio hasta la virulencia durante la adhesión de la célula huésped

Urinary tract infections (UTIs) are a major concern in public health. The prevalent uropathogenic bacterium in healthcare settings is Escherichia coli. The increasing rate of antibiotic-resistant strains demands studies to understand E. coli pathogenesis to drive the development of new therapeutic approaches. This study compared the gene expression profile of selected target genes in the prototype uropathogenic E. coli (UPEC) strain CFT073 grown in Luria Bertani (LB), artificial urine (AU), and during adhesion to host bladder cells by semi-quantitative real-time PCR (RT-PCR) assays. AU effectively supported the growth of strain CFT073 as well as other E. coli strains with different lifestyles, thereby confirming the appropriateness of this medium for in vitro models. Unexpectedly, gene expression of strain CFT073 in LB and AU was quite similar; conversely, during the adhesion assay, adhesins and porins were upregulated, while key global regulators were downregulated with respect to lab media. Interestingly, fimH and papGII genes were significantly expressed in all tested conditions. Taken together, these results provide for the first time insights of the metabolic and pathogenic profile of strain CFT073 during the essential phase of host cell adhesion.(AU)

Effect of spdC gene expression on virulence and antibiotic resistance in clinical Staphylococcus aureus isolates / Efecto de la expresión del gen spdC sobre la virulencia y la resistencia a los antibióticos en aislamientos clínicos de Staphylococcus aureus

Surface protein display C (SpdC) protein was described as a novel virulence factor of Staphylococcus aureus that affects biofilm formation and pathogenesis and favors resistance to antimicrobials targeting cell wall. We evaluated the possible correlation between spdC gene expression level and virulence as well as antibiotic resistance phenotypes in S. aureus clinical isolates. The antimicrobial susceptibility of S. aureus clinical isolates (n = 100) was determined by the disk diffusion method. Vancomycin susceptibility was determined by the broth microdilution method. The level of the extracellular proteases and delta-hemolysin was evaluated by measuring the proteolysis and hemolysis zone diameters in skim milk and blood agar plates, respectively. Biofilm formation was assayed using the 96-well microtiter plate method. Most of the isolates (81%) were multidrug-resistant and about half of the isolates (49%) were methicillin-resistant S. aureus. Hemolysin, protease, and biofilm production were detectable in 79%, 71%, and 96% of the isolates. No significant correlation was detectable between the level of spdC gene expression and the activity of tested virulence factors or the antimicrobial resistance phenotype. Therefore, the role of SpdC protein as a virulence regulator in S. aureus needs further evaluation together with the determination of the predominant regulators for each virulence factor.(AU)

Investigation of class 1 integrons and virulence genes in the emergent Salmonella serovar Infantis in Turkey / Investigación de integrones de clase 1 y genes de virulencia en Salmonella serovar Infantis emergente en Turquía

The emerging situation of Salmonella enterica subsp. enterica serovar Infantis (S. Infantis) in Turkey was investigated in terms of virulence genes and mobile genetic elements such as Salmonella genomic island 1 (SGI1) and class 1 (C1) integron to see whether increased multidrug resistance (MDR) and ability to cause human cases is a consequence of their possession. Screening of SGI1 (and its variants) and C1 integrons was done with conventional PCR, while screening of gene cassettes and virulence genes was conducted with real-time PCR for 70 S. Infantis isolates from poultry products. SGI1 or its variants were not detected in any of the isolates. Sixty-eight of 70 isolates were detected to carry one C1 integron of size 1.0 kb. These integrons were detected to carry ant(3″)-Ia gene cassette explaining the streptomycin/spectinomycin resistance. Sequence analysis of gene cassettes belongs to four representing isolates which showed that, although their difference in isolation date and place, genetically, they are 99.9% similar. Virulence gene screening was introduced as genotypic virulence profiles. The most dominant profile for S. Infantis isolates, among twelve genes, was gatC-tcfA, which are known to be related to colonization at specific hosts. This study revealed the high percentage of C1 integron possession in S. Infantis isolates from poultry products in Turkey. It also showed the potential of S. Infantis strains to be resistant to more antimicrobial drugs. Moreover, a dominant profile of virulence genes that are uncommon for non-typhoidal Salmonella (NTS) serovars was detected, which might explain the enhanced growth at specified hosts.(AU)

Genetic diversity and virulence characteristics of biofilm-producing uropathogenic Escherichia coli / Diversidad genética y características de virulencia de Escherichia coli uropatógena productora de biopelículas

Uropathogenic E. coli (UPEC) strains exhibit different levels of biofilm formation that help adhesion of the bacteria to uroepithelial cells. We investigated the genetic diversity and virulence-associated genes (VAGs) of biofilm-producing UPEC. A collection of 107 biofilm-producing (BFP) UPEC strains isolated from patients with UTI in Iran were divided into three groups of strong, moderate, and weak BFPs after a quantitative microtiter plate assay, and the involvement of curli and cellulose in adhesion of the strains to T24 cell line was confirmed by the construction of csgD and yedQ mutants of two representative UPEC strains. BFP strains were tested for their genetic diversity, phylogenetic groups, and the presence of 15 VAGs. A significant decrease in adhesion of csgD and yedQ mutant strains confirmed the role of biofilm production in adhesion to uroepithelial cells. A high diversity was found among all three groups of strong (Di = 0.998), moderate (Di = 0.998), and weak (Di = 0.988) BFPs with majority of the strains belonging to phylogroups B2 (44.9%) and A (24.3%). Strong BFP strains carried significantly higher level papEF, hlyA, and iutA than other BFP groups. In contrast, the presence of fimH, focG, sfaS, set-1, and cvaC was more pronounced among weak BFP strains. There exists a high genetic diversity among the BFP strains with different VGA profiles. However, the high prevalence of phylogroup A among BFP strains suggests the fitness of commensal E. coli strains to cause UTI in this country.(AU)

Tec1, a member of the TEA transcription factors family, is involved in virulence and basidiocarp development in Ustilago maydis / Tec1, un miembro de la familia de factores de transcripción TEA, está involucrado en la virulencia y el desarrollo de basidiocarpio en Ustilago maydis

The life cycle of Ustilago maydis involves alternation of a haploid saprophytic yeast-like stage and a dikaryotic hyphal virulent form. Under in vitro conditions, basidiocarps are formed. Analysis of the transcriptional network of basidiocarp formation revealed the possible involvement of a Tec transcription factor (Tec1, UMAG_02835) in the process. In some Ascomycota, Tec factors are involved in mycelial formation, pathogenesis, and interaction with other regulatory elements, but their role in Basidiomycota species is almost unknown. Accordingly, we proceeded to determine the role of this gene in U. maydis by its mutation. Tec1 was found to be a crucial factor for normal mating, basidiocarp development, and virulence, all of the functions related to the dikaryotic stage dependent of the b genes, whereas dimorphism and resistance to different stress conditions occurring in the haploid stage were not affected in tec1 mutants. The observation that mutants showed a low residual wild-type phenotype suggests the presence of a secondary mechanism that partially compensates the loss of Tec1.(AU)

Morphological and transcriptomic analysis of attenuated and virulent strains of Phytophthora infestans / Análisis morfológico y transcriptómico de cepas atenuadas y virulentas de Phytophthora infestans

Phytophthora infestans is a hemibiotroph Oomycete that primarily infects tomato. In this study, the growth status and pathogenicity of attenuated and virulent strains of Phytophthora infestans were determined. Furthermore, RNA-seq technology was used to explore the differences in gene transcription levels between attenuated and virulent strains. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed on the differentially expressed genes (DEGs) obtained by sequencing, and the significant DEGs related to the growth and pathogenicity of the strains were screened from the significantly enriched pathways. The results revealed that compared with the virulent strain, the growth of the attenuated strain was inhibited, the structure of hyphae was destroyed, and the disease index was decreased. The differences in the growth status and disease index of the attenuated strain were related to changes in several metabolic pathways, and the DEGs in the metabolic pathways indicated alterations in the attenuated strain growth and pathogenicity. There were 2,651 DEGs in the attenuated strain, of which 1,086 were upregulated and 1,565 were downregulated. The inhibited growth of the attenuated strain was associated with accumulation of excessive glucose, decomposition of serine/glycine, and reduction of tryptophan synthesis. The reduced pathogenicity of the strain was associated with degradation of the cell wall and reduced formation of melanin and α-keto butyric acid. These results could offer insights into the mechanisms of attenuation of Phytophthora infestans.(AU)

Diversity in the swimming motility and flagellar regulon structure of uropathogenic Morganella morganii strains / Diversidad en la motilidad natatoria y la estructura del regulón flagelar de cepas uropatógenas de Morganella morganii

In current times, the opportunistic pathogen Morganella morganii is increasingly becoming a cause of urinary tract infections. The condition has been further complicated by the multiple drug resistance of most isolates. Swimming motility plays an important role in the development of urinary tract infections, allowing bacteria to colonize the upper urinary tract. We determined the differences between the growth, swimming motility, and biofilm formation of two M. morganii strains MM 1 and MM 190 isolated from the urine of patients who had community-acquired urinary tract infections. MM 190 showed a lower growth rate but better-formed biofilms in comparison to MM 1. In addition, MM 190 possessed autoaggregation abilities. It was found that a high temperature (37 °C) inhibits the flagellation of strains and makes MM 190 less motile. At the same time, the MM 1 strain maintained its rate of motility at this temperature. We demonstrated that urea at a concentration of 1.5% suppresses the growth and swimming motility of both strains. Genome analysis showed that MM 1 has a 17.7-kb-long insertion in flagellar regulon between fliE and glycosyltransferase genes, which was not identified in corresponding loci of MM 190 and 9 other M. morganii strains with whole genomes. Both strains carry two genes encoding flagellin, which may indicate flagellar antigen phase variation. However, the fliC2 genes have only 91% identity to each other and exhibit some variability in the regulatory region. We assume that all these differences influence the swimming motility of the strains.(AU)

The genotypes and virulence attributes of C. albicans isolates from oral leukoplakia / Los genotipos y atributos de virulencia de aislamientos de C. albicans de leucoplasia oral

Background: There is a debate as to whether some types of oral leucoplakias (OL) are caused by Candida species,and whether they contribute to the malignant transformation, associated with a minority of such lesions. As nodetailed population analysis of yeast isolates from OL is available, we evaluated the virulence attributes, and geno-types of 35 C. albicans from OL, and compared their genotypes with 18 oral isolates from healthy individuals.Material and Methods: The virulence traits evaluated were esterase, phospholipase, proteinase, haemolysin andcoagulase production, and phenotypic switching activity, and yeast adherence and biofilm formation. DNA fromOL and control yeasts were evaluated for A, B or C genotype status.Results: Phospholipase, proteinase, and coagulase activity and biofilm formation was observed in 80%, 66%, 97% and 77 % of the isolates, respectively. Phenotypic switching was detected in 8.6%, while heamolytic, and ester-ase activity and adherence were noted in all isolates.Conclusions: The genotype A was predominant amongst both the OL and control groups. Due to the small samplesize of our study a larger investigation to define the role of candidal virulent attributes in the pathogenicity of OLis warranted, and the current data should serve as a basis until then.(AU)