Fernando Espinosa-Camacho

Helicobacter pylori can persist intracellularly, offering protection against the immune system and antimicrobial treatments, which promote chronic infection. Previous studies revealed that the virulence-associated protein D ( vapD ) gene is transcriptionally induced during H. pylori intracellular infection and was associated with bacterial persistence, as deletion of vapD impairs bacterial intracellular survival. However, whether VapD protein is expressed and localized during intracellular infection had not been demonstrated. The aim of this study was to detect the VapD protein when H. pylori is inside eukaryotic cells. Polyclonal antibodies against VapD and immunofluorescence microscopy were used to detect the VapD expression in co-cultures of H. pylori strain 26695 and AGS cells. The H. pylori strain Tx30a, which lacks the vapD gene, was used as a negative control. VapD expression was detected exclusively in AGS cells infected with strain 26695. Confocal microscopy confirmed the intracellular localization of the VapD signal, which coincided with the localization of H. pylori within AGS cells. In addition, a high proportion of H. pylori -infected AGS cells were positive for VapD signal. Together, these results provide first direct evidence of VapD expression during H. pylori intracellular infection and extend previous transcriptional and genetic studies by confirming VapD production at the protein level, supporting its association with the intracellular state of H. pylori .

Background: Candida species are common causes of nosocomial infections. Candida parapsilosis has emerged as an important pathogen . Mortality rates associated with invasive C. parapsilosis infections range from 14.5% to 47%, with azole resistance estimated between 4% and 15%. Resistance mechanisms include mutations in ERG11 that diminish azole binding, upregulation of ergosterol biosynthesis genes due to mutations in regulatory factors like UPC2 and NDT80 , and increased efflux pump activity. Methods: Thirty clinical strains of the C. parapsilosis complex were isolated from bloodstream cultures, biopsies and catheter tips from hospitalised patients from a major rehabilitation centre in Mexico between June 2011 and August 2016. Minimum inhibitory concentrations for fluconazole, voriconazole, itraconazole, caspofungin, micafungin, anidulafungin and amphotericin B were determined using the broth microdilution method. Whole genome sequencing was conducted using Illumina technology, with subsequent assembly and annotation. Analyses included antifungal resistance variant screening, SNP distance, average nucleotide identity and phylogenetic comparisons with publicly available genomes. Results: Most strains (96.7%, 29/30) were identified as C. parapsilosis sensu stricto, predominantly isolated from blood. Thirty‐three percent of isolates showed phenotypic resistance to fluconazole. The SNP‐distance and maximum‐likelihood phylogenetic analyses revealed two distinct haplotypes and the genotype 1: ERG11 ^WT/Y132F , CDR1 ^{I1287V/I1287V} and UPC2 ^WT/N455D was the most represented (8/10 isolates). Conclusions: C. parapsilosis sensu stricto was the predominant species isolated, with a notable proportion exhibiting resistance to FLU and VOR. The Y132F variant in the ERG11 gene was present in most sequenced isolates.

Background Pseudomonas aeruginosa is an important opportunistic pathogen especially in nosocomial infections due to its easy adaptation to different environments; this characteristic is due to the great genetic diversity that presents its genome. In addition, it is considered a pathogen of critical priority due to the high antimicrobial resistance. Objectives The aim of this study was to characterize the mobile genetic elements present in the chromosome of six Mexican P. aeruginosa strains isolated from adults with pneumonia and children with bacteremia. Methods The genomic DNA of six P. aeruginosa strains were isolated and sequenced using PacBio RS-II platform. They were annotated using Prokaryotic Genome Annotation Pipeline and manually curated and analyzed for the presence of mobile genetic elements, antibiotic resistances genes, efflux pumps and virulence factors using several bioinformatics programs and databases. Results The global analysis of the strains chromosomes showed a novel chromosomal rearrangement in two strains, possibly mediated by subsequent recombination and inversion events. They have a high content of mobile genetic elements: 21 genomic islands, four new islets, four different integrative conjugative elements, 28 different prophages, one CRISPR-Cas arrangements, and one class 1 integron. The acquisition of antimicrobials resistance genes into these elements are in concordance with their phenotype of multi-drug resistance. Conclusion The accessory genome increased the ability of the strains to adapt or survive to the hospital environment, promote genomic plasticity and chromosomal rearrangements, which may affect the expression or functionality of the gene and might influence the clinical outcome, having an impact on the treatment.