Corynebacterium striatum is part of microbiota of skin and nasal mucosa of humans and has been increasingly reported as the etiologic agent of community-acquired and nosocomial diseases. Antimicrobial multidrug-resistant (MDR) C. striatum strains have been increasingly related to various nosocomial diseases and/or outbreaks worldwide, including fatal invasive infections in immunosuppressed and immunocompetent patients. Although cases of infections by C. striatum still neglected in some countries, the improvement of microbiological techniques and studies led to the increase of survival of patients with C. striatum nosocomial infections at different levels of magnitude. Biofilm formation on abiotic surfaces contributes for the persistence of virulent C. striatum and dissemination of antimicrobial resistance in hospital environment. Besides that, empirical antibiotic therapy can select multi-resistant strains and transfer intra and interspecies genes horizontally. In this study, a worldwide survey of C. striatum human infections and nosocomial outbreaks was accomplished by the analysis of clinical–epidemiological and microbiological features of reported cases from varied countries, during a 44-year period (1976–2020).

BackgroundAnimal models are widely used in scientific research in order to obtain information from a whole organism under a specific set of experimental conditions. Various lineages of mice have been used to investigate diseases and new therapeutic strategies, and, consequently, hematological and biochemical tests in these laboratory animals are essential to validate scientific studies. Our study seeks to establish reference values for hematological and biochemical parameters of four lineages of mice.MethodsWe evaluated the hematological and biochemical profiles of 20 males and 20 females from the lineages Swiss (heterogeneous), BALB/c and C57BL/6 (isogenic), and B6D2F1 (hybrid), totaling 160 mice. Analysis were standardized using the systems pocH‐100iV Diff™ for 19 hematological parameters and VITROS® 350 for 12 biochemical parameters.ResultsResults are shown as means and standard deviation, grouped by lineage and genre. Comparing the values obtained in this study with the values from previous studies, some variations were detected, which could be explained by differences in methodologies or individual variability.ConclusionThus our study shows that knowledge and disclosure of the values of physiological parameters of laboratory animals is necessary, and emphasises the importance of considering variations influenced by gender, lineage and genotype in the choice of the best experimental model.

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Staphylococcus aureus is considered an infectious agent of great clinical importance, responsible for many different types of infection. Strains of methicillin-resistant Staphylococcus aureus (MRSA), Panton-Valentine leukocidin producers, are considered more invasive, presenting clinical sequelae related to abscesses and infection in skin and soft tissues. The use of invasive techniques in hospital environment, such as the introduction of intravascular catheter in immunocompromised patients, has contributed to this microorganism spreading through the bloodstream, causing bacteremia, necrotizing pneumonia and increasing the number of septic patients in intensive care units with high mortality. In this report, atypical infections in Swiss mice using experimental model of sepsis was presented.

Studies related to bacterial biofilm formation are extremely relevant because of their constant association with several human diseases. The organization of this sessile microbial community provides protection against opsonization and phagocytosis. It is responsible for hampering not only the immune system performance against infections but also antimicrobial activity. Staphylococcus aureus is part of healthy human microbiota including skin and nasal vestibule. However, many strains have become opportunistic pathogens because of the ability of biofilm formation in implants and medical devices by using them as route of access to bloodstream. S. aureus’ ability of biofilm formation is widely known and it has been responsible for several infections, such as endocarditis, bacteremia and sepsis. Several factors contribute to biofilm formation including expression of specific genes and interaction between proteins involved in adhesion to substrate. This work aims to explore the main aspects related to biofilm formation by S. aureus, using tools as data index bases from the scientific literature: Google Scholar, LILACS, MEDLINE (PubMed), SciELO, Scopus and Book/eBook, between July 2018 and February 2019, in English, Spanish and Portuguese. This review aims to provide a better understanding of biofilm formation and its impact on host health.

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Aims Staphylococcus aureus is one of the most common pathogens in hospital environment and community. Panton‐Valentine leukocidin (PVL) production is clinically associated with skin abscesses, soft tissues infections, bacteraemia and sepsis. This study aimed to investigate the effects of the presence of genes lukF/S‐PV coding for PVL, in histological and haematological features during systemic infection, using a Swiss mice experimental model. Methods and Results Experiments were performed using 25 mice distributed into five experimental groups, intravenously inoculated with 50 µl suspensions at density 1·0 × 107 CFU per ml of strains: methicillin‐susceptible (MSSA) and pvl‐negative strains isolated from nasal colonization; MSSA pvl‐positive strains isolated from nasal colonization; methicillin‐resistant (MRSA) and pvl‐positive strains isolated from peripheral blood of a patient with severe pulmonary infection; and a MRSA pvl‐positive strains isolated from a peripheral blood culture of a patient with bacteraemia. Haematological analysis was performed at 24, 48, 72 and 96 h post‐infection. Morphoanatomy and histopathological analyses were performed at 96 h post‐infection. For all S. aureus strains tested, the capability of intravenous dissemination and survival into mice tissues was demonstrated. Inflammatory processes at different levels were related to the presence of pvl genes, and included alterations in the format, size and colour of the organs. Staphylococcus aureus pvl‐positive strains were detected in greater numbers in the organs of the infected animals. Conclusions The pvl‐positive strains isolated from blood cultures were capable to induce the greatest modifications in both haematological and histopathological profiles, and seemed to aggravate the systemic infections. Significance and Impact of the Study These findings are valuable in characterizing infections caused by S. aureus in humans and murine.