Epidemiological data on health care-associated infections (HAIs) reported in Brazil

As Infecções Relacionadas à Assistência à Saúde (IRAS) constituem um grande problema à saúde pública mundial, já que estão relacionadas ao aumento de morbidade e mortalidade, aumentando custos hospitalares. Além disso, grande parte destas infecções estão relacionadas à microrganismos que apresentam resistência aos antimicrobianos (RM), dificultando o tratamento. Conhecer o perfil epidemiológico destas infecções contribui para o desenvolvimento de estratégias para o controle de IRAS/RM. Neste sentido, o presente trabalho realizou uma revisão bibliográfica de dados epidemiológicos das IRAS no Brasil publicados entre 2017-2022. Foram selecionadas 27 publicações científicas. 13 destas apresentaram prevalência/incidência geral de IRAS, com apenas um estudo multicêntrico, multisetorial e multietário. Os demais estudos reportaram taxas de IRAS a partir de dados epidemiológicos oriundos de infecções de corrente sanguínea, infecções de sítio cirúrgico e infecção urinária, entre outras. Quando disponíveis, os perfis microbiológicos/resistência a antimicrobianos foram incluídos, sendo compatíveis com o que reporta a literatura científica. A partir dos dados desta revisão, observou-se que, apesar dos avanços na área, os estudos que reportam taxas de IRAS ainda são escassos e limitados a um contexto específico no Brasil, evidenciando a necessidade de mais estudos multicêntricos e contínuos. Conhecer melhor a epidemiologia de IRAS a nível nacional e público possibilita um melhor planejamento, desenvolvimento de estudos científicos e implementação de estratégias de controle e mitigação destas infecções

Sourdough bacterial dynamics revealed by metagenomic analysis in Brazil.

This study dealt with the influence of the temperature on the bacterial dynamics of two spontaneously fermented wheat sourdoughs, propagated at 21 ± 1 °C (SD1) and 30 ± 1 °C (SD2), during nine backslopping steps (BS1 to BS9). Proteobacteria was the only phylum found in flour. Escherichia hermannii was predominant, followed by Kosakonia cowanii, besides species belonging to the genera Pantoea and Pseudomonas. After one step of propagation, Clostridium and Bacillus cereus group became predominant. Lactobacillus curvatus was found at low relative abundance. For the second backslopping step, Clostridium was flanked by L. curvatus and Lactobacillus farciminis. From BS4 (6th day) onward, lactic acid bacteria (LAB) became predominant. L. farciminis overcame L. curvatus and remained dominant until the end of propagations for both sourdoughs. At 21 °C, Bacillus, Clostridium, Pseudomonas, and Enterobacteriaceae were gradually inhibited. At the end of propagation, SD1 harbored only LAB. Otherwise, the temperature of 30 °C favored the persistence of atypical bacteria in SD2, as Pseudomonas and Enterobacteriaceae. Therefore, the temperature of 21 °C was more suitable for sourdough propagation in Brazil. This study enhanced the knowledge of temperature's influence on microbial assembly and contributed to the elucidation of sourdough microbial communities in Brazil

Analysis of the Caulobacter crescentus Zur regulon reveals novel insights in zinc acquisition by TonB-dependent outer membrane proteins

Abstract\ud \ud Background\ud Intracellular zinc concentration needs to be maintained within strict limits due to its toxicity at high levels, and this is achieved by a finely regulated balance between uptake and efflux. Many bacteria use the Zinc Uptake Regulator Zur to orchestrate zinc homeostasis, but little is known regarding the transport of this metal across the bacterial outer membrane.\ud \ud \ud Results\ud In this work we determined the Caulobacter crescentus Zur regulon by global transcriptional and in silico analyses. Among the genes directly repressed by Zur in response to zinc availability are those encoding a putative high affinity ABC uptake system (znuGHI), three TonB-dependent receptors (znuK, znuL and znuM) and one new putative transporter of a family not yet characterized (zrpW). Zur is also directly involved in the activation of a RND and a P-type ATPase efflux systems, as revealed by β-galactosidase and site-directed mutagenesis assays. Several genes belonging to the Fur regulon were also downregulated in the zur mutant, suggesting a putative cross-talk between Zur and Fur regulatory networks. Interestingly, a phenotypic analysis of the znuK and znuL mutants has shown that these genes are essential for growth under zinc starvation, suggesting that C. crescentus uses these TonB-dependent outer membrane transporters as key zinc scavenging systems.\ud \ud \ud Conclusions\ud The characterization of the C. crescentus Zur regulon showed that this regulator coordinates not only uptake, but also the extrusion of zinc. The uptake of zinc by C. crescentus in conditions of scarcity of this metal is highly dependent on TonB-dependent receptors, and the extrusion is mediated by an RND and P-type ATPase transport systems. The absence of Zur causes a disturbance in the dynamic equilibrium of zinc intracellular concentration, which in turn can interfere with other regulatory networks as seen for the Fur regulon.This work was supported by São Paulo Research Foundation (FAPESP) and\ud Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-Brasil).\ud During the course of this work, RRM was supported by a postdoctoral\ud fellowship grant 2011/18847-4 from FAPESP and MVM was partially supported\ud by a fellowship grant 306558/2013-0 from CNPq-Brasil

Study of Caulobacter crescentus genes important to low temperature survival.

Caulobacter crescentus sobrevive em baixas temperaturas e mostrou ser um organismo psicrotolerante e de alta resistência ao congelamento, característica resultante de múltiplos fatores. C. crescentus possui quatro genes codificantes para CSPs, sendo cspA e cspB induzidos em baixas temperaturas e cspB, cspC e cspD em fase estacionária. A ausência de cspA e cspB ou cspA e cspC confere grande deficiência de crescimento em baixas temperaturas. cspA e cspB não são autorregulados e são regulados pós-transcricionalmente via estabilização de seu mRNA e traducionalmente após o choque-frio. A expressão de cspB é influênciada por CspC a 30 graus e durante o choque-frio, e por CspC, SpdR e SpoT durante a fase estacionária. A ausência de CspC ou CspC e CspD compromete a adaptação à fase estacionária promovendo alterações morfológicas. Nenhuma das CSPs de C. crescentus é capaz de reverter o fenótipo de E. coli BX04 por expressão heteróloga, embora todas possuam atividade antiterminadora que, nestas proteínas, não depende dos mesmos aminoácidos que CspE de E. coli.Characterization of Caulobacter crescentus cold response was performed. This bacterium showed to be psicrotolerant and have remarkable freezing resistance, which may be a result of multiple traits. C. crescentus has four CSP encoding genes, being cspA and cspB cold-induced and cspB, cspC and cspD stationary phase-induced. The absence of cspA and cspB or cspA and cspC led to growth deficiency under low temperature incubation. cspA and cspB are not self-regulated and are post-transcriptionally and translationally regulated during cold-shock. The cspB gene expression is affected by CspC at exponential growth phase and by CspC, SpdR and SpoT at stationary phase. The absence of CspC, or CspC and CspD, affects stationary phase fitness of this organism, also promoting morphological alterations. None of the C. crescentus CSPs were able to restore the phenotype of E. coli BX04 strain by heterologous expression. Although all of them have shown to be transcription antiterminators, this ability is not dependent on the same critical aminoacids displayed by CspE from E. coli