The scavenging capacity of DMBT1 is impaired by germline deletions.

The Scavenger Receptor Cysteine-Rich (SRCR) proteins are an archaic group of proteins characterized by the presence of multiple SRCR domains. They are membrane-bound or secreted proteins, which are generally related to host defense systems in animals. Deleted in Malignant Brain Tumors 1 (DMBT1) is a SRCR protein which is secreted in mucosal fluids and involved in host defense by pathogen binding by its SRCR domains. Genetic polymorphism within DMBT1 leads to DMBT1-alleles giving rise to polypeptides with interindividually different numbers of SRCR domains, ranging from 8 SRCR domains (encoded by 6 kb DMBT1 variant) to 13 SRCR domains (encoded by the 8 kb DMBT1 variant). In the present study, we have investigated whether reduction from 13 to 8 amino-terminal SRCR domains leads to reduction of bacterial binding. The 6 kb variant bound ~20-45% less bacteria compared to the 8 kb variant. These results support the hypothesis that genetic variation in DMBT1 may influence microbial defense.

In vivo comparison of Dhvar-5 and gentamicin in an MRSA osteomyelitis prevention model.

OBJECTIVES: The continued rise in drug-resistant pathogens has led to global research efforts into new antimicrobial agents. A promising class of new agents are the antimicrobial peptides. The aim of the study was to investigate the efficacy of the antimicrobial peptide Dhvar-5 in a prophylactic, methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis model. METHODS: Dhvar-5 (12 mg or 24 mg/rabbit) was incorporated into polymethyl methacrylate (PMMA) beads as a local drug delivery system. For comparison, plain beads (control) and beads containing gentamicin as a sulphate (10 mg or 24 mg per rabbit) were also prepared. The beads were inserted into the inoculated femoral cavity of 36 rabbits, and 1 week later they were killed. The presence and severity of MRSA osteomyelitis was assessed by culture and histology. RESULTS: Both the 24 mg Dhvar-5 beads and the 24 mg gentamicin sulphate beads significantly reduced the bacterial load of the inoculated femora compared with the control chain. Although a 24 mg Dhvar-5 dose inhibited MRSA growth, it did not completely sterilize the femora. Sterilization occurred only in some of the gentamicin-treated specimens. CONCLUSION: We conclude that both the gentamicin beads and the Dhvar-5 beads were only partially effective at preventing MRSA infection in this model.

Inadequate salivary flow and poor oral mucosal status in intubated intensive care unit patients.

OBJECTIVE: To investigate salivary flow and frequency of oral mucositis in intensive care unit patients compared with patients admitted because of elective coronary artery bypass graft (CABG) surgery. In addition, the pattern of oropharyngeal colonization was investigated in these patients. DESIGN: Prospective study. SETTING: Mixed intensive care unit and cardiosurgical ward. PATIENTS: In this study, 24 ventilated intensive care unit patients and 20 CABG patients were included. MEASUREMENTS AND MAIN RESULTS: Two dental hygienists examined intensive care unit patients for the presence of periodontal disease and mucositis at admission and subsequently every week during their stay in the intensive care unit. At the same time, stimulated salivary flow and salivary total immunoglobulin A output were measured. Oropharyngeal cultures were obtained as well. CABG patients were examined the day before the operation, 1 day, 1 wk, and 2 wks after the operation. The following results were obtained: a) temporarily reduced postoperative stimulated salivary flow and total salivary immunoglobulin A output in CABG patients and nearly absent stimulated salivary flow in intensive care unit patients; b) oropharyngeal colonization with potentially pathogenic microorganisms in intensive care unit and not in CABG patients; and c) the increase in mucositis index in intensive care unit patients paralleled the increase in potentially pathogenic microorganism oropharyngeal colonization, especially and. CONCLUSIONS: Absence of adequate salivary flow in intubated intensive care unit patients causes severe xerostomia, which may contribute to the development of mucositis and oropharyngeal colonization with Gram-negative bacteria.

The influence of antimicrobial peptides and mucolytics on the integrity of biofilms consisting of bacteria and yeasts as affecting voice prosthetic air flow resistances.

The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses afterm biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance.