The influence of inoculum size, beta-lactamase hyperproduction (multicopy plasmid) and modifications in the outer membrane protein profile on the susceptibility of Escherichia coli to combinations of amoxycillin/clavulanate, amoxycillin/sulbactam, amoxycillin/tazobactam and piperacillin/tazobactam were studied. For all combinations the bacterial susceptibility was affected by factors determining an increase in beta-lactamase (inoculum size or hyperproduction). Clavulanic acid was the most efficient beta-lactamase inhibitor. The absence of the outer membrane proteins, OmpF and OmpC, did not significantly affect susceptibility to the combinations per se but when combined with the presence of beta-lactamase high MICs were observed. Seven out of eight amoxycillin/clavulanate resistant clinical isolates of E. coli had beta-lactamase hyperproduction and a decrease or absence of OmpF.
Three high-level vancomycin-resistant Enterococcus strains (two Enterococcus faecium and one Enterococcus durans) were recovered from three of eight sewage samples taken from the general sewage collector at Logroño (Northern Spain). The strains were present in the sewage samples at estimated concentrations of ten resistant bacteria/mL, corresponding to about 0.4% of the enterococcal population. The VanA protein was detected in each strain by immunoblotting of membrane extracts of the vancomycin-induced cells, and the vanA gene was demonstrated in the wild strains and their transconjugants by DNA-DNA hybridization. This is the first, confirmed report of vanA mediated vancomycin resistance in E. durans.
The vaccines designed against the SARS-CoV-2 coronavirus are based on the spike (S) protein. Processing of the S protein by antigen-presenting cells (APC) and its subsequent presentation to T cells is an essential part of the development of a humoral response. HLA-class II alleles are considered immune response genes because their codified molecules, expressed on the surface of APCs (macrophages, dendritic, and B cells) present antigenic peptides to T cell via their T cell receptor (TCR). The HLA-class II genes are highly polymorphic, regulating what specific peptides induce follicular helper T cells (TFH) and promote B lymphocyte differentiation into plasma or memory B cells. This work hypothesizes that the presence of certain HLA-class II alleles could be associated with the intensity of the humoral response (amount, length) to the SARS-CoV2 mRNA 1273 vaccine. We have studied the relationship between the HLA-class II typing of 87 health workers and the level of antibodies produced 30 days after vaccination. We show a possible association between the HLA-DRB1* 07:01 allele and the HLA-DRB1*07:01~DQA1*02:01~DQB1*02:02 haplotype to a higher production of antibodies 30 days after the administration of the second dose of mRNA-1273.
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