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).

Staphylococcus haemolyticus is the most common organism among clinical isolatesof methicillin-resistant staphylococci. Aim: This study evaluated the ability to produce biofilm with the presence of the antibiotics (1/4 minimum inhibitory concentrations) of S. haemolyticus strains isolated from blood culture. Methods: Clonal distribution was assessed in pulsed-field gel electrophoresis. PCR assays were performed to detect mecA, icaA, aap, atlE, atl, fbp genes. S. haemolyticus strains grown in the presence of the antibiotics were investigated for biofilm formation on glass, polystyrene and catheter surfaces. Results: Biofilm formation was independent of the presence of the icaA and mecA genes, pulsed-field gel electrophoresis type. Vancomycin, oxacillin, moxifloxacin, rifampicin, teicoplanin, tigecycline and linezolid did not inhibit biofilm formation on abiotic surfaces. Conclusion: This study demonstrated that the biofilm formation process is complex and may not be related to ica gene carriage. Furthermore, in this study the biofilm formation was increased in the presence of antimicrobial agents.

The presence of multi-drug resistant (MDR) E. coli harboring virulence pathotypes in aquatic systems is a public health concern due to an increase number of cases of infections and outbreaks in industrialized and developing countries. The aim of the present study was to evaluate the microbiological quality of Joana river, located at Rio de Janeiro, by analyzing E. coli bacteria contamination and to investigate virulence properties and MDR profiles by phenotypic and genotypic methods, including bacterial interaction with Caco-2 cells. A total of 34 E. coli were identified by MALDI-TOF and 20 E. coli were characterized as MDR when submitted to antimicrobial susceptibility test. Evaluation by multiplex-PCR of MDR E. coli demonstrated the presence of virulence pathotypes: EHEC (stx1, stx2, eae genes), STEC (stx2 gene) and EIEC/STEC (stx2, iaL genes). Virulence potential was demonstrated by the ability to adhere and survive within Caco-2 cells of MDR E. coli pathotypes (n = 4). In conclusion, this study demonstrates the presence of diarrheagenic MDR E. coli in river water at Rio de Janeiro. The possibility of aquatic environment dissemination of antimicrobial resistance and human contamination leading to community and nosocomial infections due to virulent MDR E. coli water-borne pathogens is a matter of concern.

Last-resort antibiotics act as ultimate force to overcome multidrug-resistant strains infections. Cases of tigecycline resistance in gram-negative bacilli in clinical settings are reported worldwide, however, there is no data related to tigecycline resistant strains in river water. This study demonstrates seven tigecycline gram-negative bacilli isolated from river water in Rio de Janeiro metropolitan area, their resistance genes, ability of biofilm formation with/without antibiotics and behavior using the nematode Caenohabidits elegans as infection in vivo model. From 24 gram-negative isolated strains, 16 (66.6%) were classified as multidrug-resistant, however, seven (29.1%) presented resistant to all antimicrobial agents tested, including tigecycline and have been identified by MALDI-TOF as A. baumannii, E. aerogenes and P. agglomerans. All tigecycline-resistant strains presented amplification products for ESBL, AME and PMQR