Prevention, inhibition, and degradation effects of melittin alone and in combination with vancomycin and rifampin against strong biofilm producer strains of methicillin-resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) bacteria are being recognized as true pathogens as they are able to resist methicillin and commonly form biofilms. Recent studies have shown that antimicrobial peptides (AMPs) are promising agents against biofilm-associated bacterial infections. In this study, we aimed to explore the antibiofilm activity of melittin, either alone or in combination with vancomycin and rifampin, against biofilm-producing MRSE strains. Minimum biofilm preventive concentration (MBPC), minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC), as well as fractional biofilm preventive-, inhibitory-, and eradication concentrations (FBPCi, FBICi, and FBECi), were determined for the antimicrobial agents tested. Cytotoxicity and hemolytic activity of melittin at its synergistic concentration were examined on human embryonic kidney cells (HEK-293) and Red Blood Cells (RBCs), respectively. The effect of melittin on the downregulation of biofilm-associated genes was explored using Real-Time PCR. MBPC, MBIC, and MBEC values for melittin were in the range of 0.625–20, 0.625–20, and 10–40 μg/μL, respectively. Melittin showed high synergy (FBPCi, FBICi and FBECi < 0.5). The synergism resulted in a 64–512-fold, 2–16 and 2–8-fold reduction in melittin, rifampicin and vancomycin concentrations, respectively. The synergistic melittin concentration found to be effective did not manifest either cytotoxicity on HEK-293 or hemolytic activity on RBCs. Results showed that melittin downregulated the expression of biofilm-associated icaA, aap, and psm genes in all isolates tested, ranging from 0.04-folds to 2.11-folds for icaA and from 0.05 to 3.76-folds for aap and psm. The preventive and therapeutic indexes of melittin were improved 8-fold when combined with vancomycin and rifampin. Based on these findings, the combination of melittin with conventional antibiotics could be proposed for treating or preventing biofilm-associated MRSE infections

Bacterial biofilm in colorectal cancer: What is the real mechanism of action?

Human colorectal cancer is the third most common cancer around the world. Colorectal cancer has various risk factors, but current works have bolded a significant activity for the microbiota of the human colon in the development of this disease. Bacterial biofilm has been mediated to non-malignant pathologies like inflammatory bowel disease but has not been fully documented in the setting of colorectal cancer. The investigation has currently found that bacterial biofilm is mediated to colon cancer in the human and linked to the location of human cancer, with almost all right-sided adenomas of colon cancers possessing bacterial biofilm, whilst left-sided cancer is rarely biofilm positive. The profound comprehension of the changes in colorectal cancer can provide interesting novel concepts for anticancer treatments. In this review, we will summarize and examine the new knowledge about the links between colorectal cancer and bacterial biofilm. © 202

Role of microbiota-derived short-chain fatty acids in cancer development and prevention

Following cancer, cells in a particular tissue can no longer respond to the factors involved in controlling cell survival, differentiation, proliferation, and death. In recent years, it has been indicated that alterations in the gut microbiota components, intestinal epithelium, and host immune system are associated with cancer incidence. Also, it has been demonstrated that the short-chain fatty acids (SCFAs) generated by gut microbiota are vitally crucial in cell homeostasis as they contribute to the modulation of histone deacetylases (HDACs), resulting effected cell attachment, immune cell immigration, cytokine production, chemotaxis, and the programmed cell death. Therefore, the manipulation of SCFA levels in the intestinal tract by alterations in the microbiota structure can be potentially taken into consideration for cancer treatment/prevention. In the current study, we will explain the most recent findings on the detrimental or protective roles of SFCA (particularly butyrate, propionate, and acetate) in several cancers, including bladder, colon, breast, stomach, liver, lung, pancreas, and prostate cancers. © 2021 The Author

The emerging role of exosomal miRNAs as a diagnostic and therapeutic biomarker in Mycobacterium tuberculosis infection

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), has been the world�s driving fatal bacterial contagious disease globally. It continues a public health emergency, and around one-third of the global community has been affected by latent TB infection (LTBI). This is mostly due to the difficulty in diagnosing and treating patients with TB and LTBI. Exosomes are nanovesicles (40�100 nm) released from different cell types, containing proteins, lipids, mRNA, and miRNA, and they allow the transfer of one�s cargo to other cells. The functional and diagnostic potential of exosomal miRNAs has been demonstrated in bacterial infections, including TB. Besides, it has been recognized that cells infected by intracellular pathogens such as Mtb can be secreting an exosome, which is implicated in the infection�s fate. Exosomes, therefore, open a unique viewpoint on the investigative process of TB pathogenicity. This study explores the possible function of exosomal miRNAs as a diagnostic biomarker. Moreover, we include the latest data on the pathogenic and therapeutic role of exosomal miRNAs in TB. © 2021, The Author(s)

Bacterial co-infections with SARS-CoV-2

The pandemic coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has affected millions of people worldwide. To date, there are no proven effective therapies for this virus. Efforts made to develop antiviral strategies for the treatment of COVID-19 are underway. Respiratory viral infections, such as influenza, predispose patients to co-infections and these lead to increased disease severity and mortality. Numerous types of antibiotics such as azithromycin have been employed for the prevention and treatment of bacterial co-infection and secondary bacterial infections in patients with a viral respiratory infection (e.g., SARS-CoV-2). Although antibiotics do not directly affect SARS-CoV-2, viral respiratory infections often result in bacterial pneumonia. It is possible that some patients die from bacterial co-infection rather than virus itself. To date, a considerable number of bacterial strains have been resistant to various antibiotics such as azithromycin, and the overuse could render those or other antibiotics even less effective. Therefore, bacterial co-infection and secondary bacterial infection are considered critical risk factors for the severity and mortality rates of COVID-19. Also, the antibiotic-resistant as a result of overusing must be considered. In this review, we will summarize the bacterial co-infection and secondary bacterial infection in some featured respiratory viral infections, especially COVID-19. © 2020 International Union of Biochemistry and Molecular Biolog

Correction to: The emerging role of probiotics as a mitigation strategy against coronavirus disease 2019 (COVID�19) (Archives of Virology, (2021), 166, 7, (1819-1840), 10.1007/s00705-021-05036-8)

Authors would like to correct the error in their publication. The original article has been corrected. 1. Reference 17 is incorrect. The correct one should be �The probiotic Bifidobacterium in the management of Coronavirus: A theoretical basis� https://doi.org/10.1177/2058738420961304. 2. The unnecessary symbol �??� found in text is deleted. © 2021, Springer-Verlag GmbH Austria, part of Springer Nature

The biofilm-associated bacterial infections unrelated to indwelling devices

Biofilms are microbial communities established in the self-produced extracellular substances that include up to 80 of associated microbial infections. During biofilm formation, bacterial cells shift from the planktonic forms to aggregated forms surrounded by an extracellular polymeric substance. The bacterial biofilm shows resistance against immune reactions as well as antibiotics and is potentially able to cause disorders by both device-related and nondevice-related infections. The nondevice-related bacterial biofilm infections include dental plaque, urinary tract infections, cystic fibrosis, otitis media, infective endocarditis, tonsillitis, periodontitis, necrotizing fasciitis, osteomyelitis, infectious kidney stones, and chronic inflammatory diseases. In this review, we will summarize and examine the literature about bacterial biofilm infections unrelated to indwelling devices. © 2020 International Union of Biochemistry and Molecular Biolog

Genome‐wide association study for host genetic factors associated with equine herpesvirus type‐1 induced myeloencephalopathy

BackgroundEquid herpesvirus (EHV-1) infections in horses can lead to equine herpesvirus myeloencephalopathy (EHM), characterised by neurological clinical signs. The sporadic occurrence of the disease in horse herds suggests a host genetic component. A recent study reported an association between the occurrence of EHM and genetic markers on horse chromosome 6 (ECA6).ObjectivesTo investigate the association of EHM with genetic host factors, especially with reference to the association reported for ECA6.Study designGenome-wide association study (GWAS) was conducted based on 94 horses that had EHV-1 infections and comparing the 27 developing clinical EHM to the 67 which did not.MethodsDNA samples were tested from 94 horses for 382,529 single nucleotide polymorphisms (SNPs) with the Affymetrix Axiom 670K SNP array to identify possible associations with EHM. The data analysis included tests for basic, additive, dominant and recessive modes of inheritance, haplotype associations and runs of homozygosity (ROH).ResultsResults from this study did not identify significant SNPs, haplotypes or ROH associations with the development of EHM following EHV-1 infections and excluded the involvement of a recessive genetic factor in the susceptibility to develop EHM.Main limitationsSample size and complex phenotype.ConclusionsThe results exclude the involvement of a recessive genetic factor in the susceptibility to develop clinically apparent EHM but do not have the power to exclude the involvement of other, complex host genetic factors. Furthermore, there was no association between development of EHM and genes on equine chromosome 6, as previously reported