Eva Ramírez de Arellano

Gastroenteritis is a major cause of morbidity in young children worldwide. A prospective multicentre study was conducted from September 2020 to September 2021 in three tertiary hospitals in Spain to assess the burden of the gastrointestinal pathogens causing paediatric gastroenteritis in different Spanish regions, to understand the impact of COVID-19 pandemic in their incidence, and to assess potential risk factors for infection. Stool samples from children aged 0-59 months with acute or chronic diarrhoea were analysed by PCR to detect and characterise gastrointestinal bacteria, parasites, and viruses. Whole-genome sequencing was carried out on enteroaggregative Escherichia coli isolates. Epidemiological and clinical data were analysed using univariable and multivariable logistic regression models. A total of 1114 children were included (median age, 16 months; 57.3% male). The most prevalent bacteria were enteropathogenic E. coli (16.0%) and Campylobacter spp. (15.0%). Giardia duodenalis (9.8%) and Cryptosporidium parvum (1.8%) were the most common parasites, while norovirus (5.5%) predominated among viruses. Molecular analyses revealed substantial genetic diversity across all pathogens. Campylobacter infection increased with age and was associated with fever and bloody diarrhoea, while norovirus infection decreased with age and was associated with vomiting.Conclusion COVID-19 countermeasures substantially altered the transmission of faecal-orally transmitted gastrointestinal pathogens in children, particularly reducing person-to-person spread of human-adapted pathogens such as C. hominis and endemic enteroaggregative E. coli subtypes. Zoonotic pathogens were largely unaffected, highlighting the selective impact of non-pharmaceutical interventions on anthroponotic transmission. What is Known: • Paediatric gastroenteritis is caused by faecal-orally transmitted viral, bacterial, and parasitic agents. • COVID-19 countermeasures contributed to the significant reduction of person-to-person transmitted gastrointestinal pathogens. What is New: • COVID-19 countermeasures drastically interrupted the person-to-person transmission of human-adapted Cryptosporidium hominis and endemic enteroaggregative Escherichia coli subtypes in Spanish children. • Cryptosporidium parvum and other zoonotically transmitted gastrointestinal pathogens were largely unaffected.

Multidrug-resistant gram-negative bacteria (MDR-GNB) are one of the main challenges in intensive care units (ICUs), mainly extended-spectrum β-lactamase-producing Klebsiella pneumoniae (EKP), carbapenemase-producing Enterobacterales, carbapenem-resistant (CR) Pseudomonas aeruginosa, and CR Acinetobacter spp. The objectives were to determine the prevalence and incidence of colonization/infection by these bacteria in Spanish ICUs, their antimicrobial susceptibility, resistome, and phylogeny. All patients admitted to ICUs of seven Spanish hospitals were evaluated (15 February to 30 March 2023). Colonization was determined in rectal and oropharyngeal swabs upon admission and the first and second weeks after admission. Infections were studied for up to 60 days from admission. Antimicrobial susceptibility was determined by broth microdilution. Whole-genome sequencing was performed to analyze the resistome and phylogeny (core-genome Multi-Locus Sequence-Typing). In total, 767 patients were studied. The prevalence of MDR-GNB colonization on admission was 2.9% (23/767), and EKP was the most prevalent bacterium. The incidence of acquired colonization was 1.3 (22/1,694) cases per 100 ICU-admitted patients-day, with colonization by CR P. aeruginosa being the most frequent ( n = 14/22). Twenty-one patients had an infection (prevalence: 2.7%), mainly CR P. aeruginosa (12/21). The major resistance mechanisms and clones detected were some of the most frequent circulating clones in Spain: EKP-ST15/ bla _VIM-1+OXA-48 , EKP-ST307/ bla _CTXM-15 , and CR P. aeruginosa ST175/OprD porin deficiency. The antibiotics with the greatest activity against Enterobacterales ( n = 26) were colistin, cefiderocol, and meropenem-vaborbactam (100%); while in CR P. aeruginosa ( n = 20), they were colistin, cefiderocol, and imipenem-relebactam (95%–100%). The prevalence/incidence of colonization/infection by MDR-GNB in the ICUs of this study was low, but with important variations between hospitals. CR P. aeruginosa was the most common bacterium identified. IMPORTANCE: This comprehensive study integrates incidence/prevalence, clinical, microbiological, and genomic data to provide an up-to-date overview of multidrug-resistant gram-negative bacteria in Spanish intensive care units (ICUs). Its main strengths lie in its multidisciplinary approach and in the involvement of seven ICUs from major university hospitals across different regions in Spain. We believe that monitoring resistance epidemiology at the ICU level—especially through molecular surveillance of resistance mechanisms and clonal dissemination—is essential for optimizing antimicrobial use and guiding stewardship and infection control programs. Notably, carbapenem-resistant Pseudomonas aeruginosa was the most frequently identified organism in both colonization (first/second week) and infection cases, highlighting the need for its inclusion in routine hospital colonization screening.

Certain host genetic variants, especially in the human leucocyte antigen (HLA) region, are associated with different progression of HIV-1-induced diseases and AIDS. Long term non progressors (LTNP) represent only the 2% of infected patients but are especially relevant because of their efficient HIV control. In this work we present a global analysis of genetic data in the large national multicenter cohort of Spanish LTNP, which is compared with seronegative individuals and HIV-positive patients. We have analyzed whether several single-nucleotide polymorphisms (SNPs) including in key genes and certain HLA-A and B alleles could be associated with a specific HIV phenotype. A total of 846 individuals, 398 HIV-1-positive patients (213 typical progressors, 55 AIDS patients, and 130 LTNPs) and 448 HIV-negative controls, were genotyped for 15 polymorphisms and HLA-A and B alleles. Significant differences in the allele frequencies among the studied populations identified 16 LTNP-associated genetic factors, 5 of which were defined for the first time as related to LTNP phenotype: the protective effect of HLA-B39, and the detrimental impact of HLA-B18, -A24, -B08 and –A29. The remaining eleven polymorphisms confirmed previous publications, including the protective alleles HLA-B57, rs2395029 (HCP5), HLA bw4 homozygosity, HLA-B52, HLA-B27, CCR2 V64I, rs9264942 (HLA-C) and HLA-A03; and the risk allele HLA bw6 homozygosity. Notably, individual Spanish HIV-negative individuals had an average of 0.12 protective HLA alleles and SNPs, compared with an average of 1.43 protective alleles per LTNP patient, strongly suggesting positive selection of LTNP. Finally, stratification of LTNP according to viral load showed a proportional relationship between the frequency of protective alleles with control of viral load. Interestingly, no differences in the frequency of protection/risk polymorphisms were found between elite controllers and LTNPs maintaining viral loads <2.000 copies/mL throughout the follow-up.

Although Lloviu virus (LLOV) was discovered in the carcasses of insectivorous Schreiber’s Bent-winged bats in the caves of Northern Spain in 2002, its infectivity and pathogenicity remain unclear. We examined the seroprevalence of LLOV in potentially exposed Schreiber’s Bent-winged bats (n = 60), common serotine bats (n = 10) as controls, and humans (n = 22) using an immunoblot assay. We found antibodies against LLOV GP₂ in all of Schreiber’s Bent-winged bats serum pools, but not in any of the common serotine bats and human pools tested. To confirm this seroreactivity, 52 serums were individually tested using Domain Programmable Arrays (DPA), a phage display based-system serology technique for profiling filovirus epitopes. A serological signature against different LLOV proteins was obtained in 19/52 samples tested (36.5%). The immunodominant response was in the majority specific to LLOV-unique epitopes, confirming that the serological response detected was to LLOV. To our knowledge, this is the first serological evidence of LLOV exposure in live captured Schreiber’s Bent-winged bats, dissociating LLOV circulation as the cause of the previously reported die-offs.