Hard-to-heal peripheral wounds infected with Corynebacterium striatum: a prospective study.

OBJECTIVE: To investigate Corynebacterium striatum as a nosocomial pathogen infecting hard-to-heal peripheral wounds, such as skin wounds, soft tissue abscesses and osteomyelitis. As of 2023, the medical community were alerted against the risk of emerging systemic and central infections; on the other hand literature on peripheral cutaneous regions is still scarce. METHOD: In this study, two groups of patients with similar lesions which were infected were compared: one group with the presence of the coryneform rod, the other without. RESULTS: In total, Corynebacterium striatum was cultured from 62 patients and 131 samples. Corynebacterium striatum infection correlated well with the presence of: foot ulcer; venous leg ulcer; altered ambulation and/or altered foot loading; peripheral vascular and arterial disease; hospitalisation; malignancy; spinal cord injury; and recent administration of antibiotics (p<0.05 for all associations). Patients with Corynebacterium striatum had a lower overall survival rate compared to patients in the non-Corynebacterium striatum group (28.6 versus 31.6 months, respectively; p=0.0285). Multivariate analysis revealed that Corynebacterium striatum infection was an independent factor for poor prognosis (p<0.0001). CONCLUSION: In view of the findings of our study, Corynebacterium striatum appears to be an important opportunistic pathogen infecting peripheral tissues and complicating wound healing. Given its numerous and worrying virulence factors (such as multidrug resistance and biofilm production), particular attention should be given to this pathogen by professional wound care providers in nosocomial and outpatient environments.

Lentiviral small hairpin RNA delivery reduces apical sodium channel activity in differentiated human airway epithelial cells.

BACKGROUND: Epithelial sodium channel (ENaC) hyperactivity has been implicated in the pathogenesis of cystic fibrosis (CF) by dysregulation of fluid and electrolytes in the airways. In the present study, we show proof-of-principle for ENaC inhibition by lentiviral-mediated RNA interference. METHODS: Immortalized normal (H441) and CF mutant (CFBE) airway cells, and differentiated human bronchial epithelial cells in air liquid interface culture (HBEC-ALI) were transduced with a vesicular stomatitis virus G glycoprotein pseudotyped lentiviral (LV) vector expressing a short hairpin RNA (shRNA) targeting the α subunit of ENaC (ENaCα), and a marker gene. Efficacy of ENaCα down-regulation was assayed by the real-time polymerase chain reaction (PCR), membrane potential assay, western blotting, short-circuit currents and fluid absorption. Off-target effects were investigated by a lab-on-a-chip quantitative PCR array. RESULTS: Transduction to near one hundred percentage efficiency of H441, CFBE and HBEC-ALI was achieved by the addition of the LV vector before differentiation and polarization. Transduction resulted in the inhibition of ENaCα mRNA and antigen expression, and a proportional decrease in ENaC-dependent short circuit current and fluid transport. No effect on transepithelial resistance or cAMP-induced secretion responses was observed in HBEC-ALI. The production of interferon α and pro-inflammatory cytokine mRNA, indicating Toll-like receptor 3 or RNA-induced silencing complex mediated off-target effects, was not observed in HBEC-ALI transduced with this vector. CONCLUSIONS: We have established a generic method for studying the effect of RNA interference in HBEC-ALI using standard lentiviral vectors. Down-regulation of ENaCα by lentiviral shRNA expression vectors as shown in the absence off-target effects has potential therapeutic value in the treatment of cystic fibrosis.

Endocarditis caused by Lactobacillus jensenii in an immunocompetent patient.

Lactobacilli are Gram-positive rod-shaped bacteria that inhabit the oral cavity, gastrointestinal tract, vagina and nasal cavity. In this report, a rare case of Lactobacillus jensenii endocarditis in a 47-year-old immunocompetent patient is described. Blood cultures and a replaced mitral valve were positive for L. jensenii as assessed by 16S rRNA gene sequencing. Based on susceptibility tests the patient was successfully treated with a mixture of teicoplanin and meropenem antimicrobial therapy.

Design and validation of siRNAs and shRNAs.

RNAi is a highly conserved intracellular mechanism, whereby dsRNA strands conduct post-transcriptional modulation of gene expression through a degradation or inhibition of the translation of target mRNA. Since its discovery in 1998, RNAi has been identified in many different organisms, including mammals, and this mechanism has provided new approaches for studies in cellular and molecular biology, functional genomics and drug discovery. siRNAs can be predicted by sequence and thermodynamic features, and the wide and proficient application of RNAi relies on the ability to select the most active siRNAs from among numerous predicted molecules. Recently, the first-generation prediction algorithms based on the characteristics of siRNAs, short hairpin (sh)RNAs and micro-(mi)RNAs have been improved by the use of computational models that account for the experimentally determined activities of large numbers of siRNAs/shRNAs and miRNAs. These second-generation algorithms differ from the first-generation algorithms in the computational tools that are used for the prediction of siRNA efficacy; although these new algorithms improve the design of effective siRNAs, they do not eliminate the requirement for an experimental evaluation of the activities of siRNAs. This review reports on the most significant second-generation algorithms of siRNA and shRNA characteristics, as well as on recently designed systems for the experimental evaluation of siRNA activities.