Possible role of HLA class-I genotype in SARS-CoV-2 infection and progression: A pilot study in a cohort of Covid-19 Spanish patients.

Human Leukocyte Antigen (HLA) includes a large set of genes with important actions in immune response against viral infection. Numerous studies have revealed the existence of significant associations between certain HLA alleles and the susceptibility and prognosis of different infectious diseases. In this pilot study we analyse the binding affinity between 66 class I HLA alleles and SARS-CoV-2 viral peptides, and its association with the severity of the disease. A total of 45 Spanish patients with mild, moderate and severe SARS-CoV-2 infection were typed for HLA class I; after that, we analysed if an in silico model of HLA I-viral peptide binding affinity and classical HLA supertypes could be correlated to the severity of the disease. Our results suggest that patients with mild disease present Class I HLA molecules with a higher theoretical capacity for binding SARS-Cov-2 peptides and showed greater heterozygosity when comparing them with moderate and severe groups. In this regard, identifying HLA-SARS-CoV-2 peptides binding differences between individuals would help to clarify the heterogeneity of clinical responses to the disease and will also be useful to guide a personalized treatment according to its particular risk.

Isolated De Novo Headache as the Presenting Symptom of Listeria Meningitis: A Report of 2 Cases.

BACKGROUND: Headache is a frequent symptom at the onset of Listeria meningitis, accompanied by others such as fever, altered mental status and meningeal signs, but never reported so far as an isolated symptom. METHODS AND RESULTS: Two immunocompetent males, with no history of primary headaches, went to the emergency department because of headache. The first after a sudden severe, holocranial headache without other associated symptoms, and the second after a subacute, moderate oppressive headache in temples, which 8 days later added a mild left hemiparesis. None of them had fever or meningeal signs. The initial cranial CT was unremarkable in both cases. Lumbar puncture was diagnostic for Listeria meningitis serotype IVb. CONCLUSIONS: Listeria meningitis may present as an isolated headache, with different clinical patterns, which should be taken into account when evaluating de novo unclassified headaches according to the ICHD-3 criteria.

Epidemiology of Aeromonas spp. isolated from stool in a tertiary hospital in Cantabria, Northern Spain, in the last five years.

INTRODUCTION: The role of Aeromonas species in gastrointestinal disease is controversial. The aim of this study was to know the epidemiological distribution of Aeromonas spp. isolated from stool in our health area, determine the existence of diarrhea as a significant symptom, identification of existing species in our environment and association as co-pathogen. METHODS: It was a retrospective descriptive study of isolates of Aeromonas spp. in feces (2016-2020). The protocol for these isolates included coproculture, identification by MALDI-TOF (Vitek-MS®, BioMerieux) and confirmation by multiplex PCR. RESULTS: A total of 366 Aeromonas spp. isolates were analyzed being Aeromonas caviae the most prevalent species (289, 78.7%). A total of 58 (15.8%) co-infections were identified, being more frequent in pediatric age (49;84.5%) (p=0.01) and mostly associated with Campylobacter spp. DISCUSSION: Aeromonas spp. prove to be a gastrointestinal pathogen more frequently associated with co-infections in pediatric age, evidencing its appearance especially with Campylobacter spp.

Virulence genes of Aeromonas spp. isolates from stool in Spain.

INTRODUCTION: The role of Aeromonas species in gastrointestinal disease is controversial. The aim was to analyze not only the virulence genes between different species of Aeromonas isolated from feces, but the distribution of these virulence genes between enterotoxigenic strains and co-pathogen strains. METHODS: Retrospective study of isolates of Aeromonas spp. in feces (2016-2021). The protocol included coproculture, identification by MALDI-TOF and confirmation by multiplex PCR. SPSS Statistics program was used. RESULTS: A total of 288 strains were studied for the virulence genes between different species of Aeromonas. To compare virulence genes between Aeromonas as co-pathogen and those isolated alone, 218 strains of the global set were used; 52 as co-pathogens compared with 166 Aeromonas without associated pathogen as controls. CONCLUSIONS: We found no significant differences in the distribution of virulence genes versus co-existence of co-pathogens or not. A. hydrophila is the potentially most virulent species of our set.

Characterization, antifungal susceptibility and virulence of Candida parapsilosis complex isolates in a tertiary hospital in Cantabria, Northern Spain.

INTRODUCTION: The correct identification of the species within the Candida parapsilosis complex has become relevant due to the resistance of Candida metapsilosis to antifungals. We describe the characteristics of the Candida parapsilosis complex isolates, with respect to antifungal resistance and biofilm formation. METHODS: We perform a descriptive cross-sectional study in 30 strains, collected in a tertiary hospital. All strains, were identified by Vitek2, Vitek-MS™ systems and by ITS sequencing. The antifungal susceptibility profile was obtained with Sensititre™ panels, while biomass production and metabolic activity were quantified by means of crystal violet and XTT reduction assay, respectively. RESULTS: There was a 100% correlation between Vitek-MS™ and ITS sequencing. All isolates were susceptible to the nine antifungals tested. The metabolic activity and biomass production tests did not show any difference among the subtypes. CONCLUSIONS: The Vitek-MS™ system provides acceptable identification. We did not find significant differences neither in azole resistance nor in biofilm formation.

Evaluation of Vitek-MS™ and Microflex LT™ commercial systems for identification of Acinetobacter calcoaceticus-baumannii complex.

INTRODUCTION: Acinetobacter is a genus that comprises a group of opportunistic pathogens responsible for a variety of nosocomial infections. The Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) complex includes some species of clinical importance, mainly A. baumannii, A. pittii and A. nosocomialis, which share phenotypic similarities that make it very difficult to distinguish between them using a phenotypic approach. The aim of this study was to evaluate two commercial matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems for the identification of different Acinetobacter species, with a special focus among those belonging to the Acb complex. METHODS: One hundred and fifty-six Acinetobacter spp. clinical strains, identified by amplified ribosomal DNA restriction analysis (ARDRA) and rpoB gene sequencing, were analysed by two different MALDI-TOF systems. RESULTS: Considering only the 144 strains of the Acb complex evaluated in this study, the Vitek-MS™ and Microflex LT™ systems correctly identified 129 (89.6%) and 143 (99.3%) strains, respectively. CONCLUSION: After analysing 156 strains belonging to Acinetobacter spp., both Vitek-MS™ and Microflex LT™ proved to be rapid and accurate systems for the identification of Acb complex species showing a good correlation. However, both manufacturers should improve their databases to include new species in them.