The role of fibrinogen in staphylococcal adherence to catheters in vitro
Infusion therapy is administered in one form or another to approximately 20 million hospitalized patients each year. This treatment procedure can potentially cause disease. Hospital data indicate that as many as one third of these iatrogenic (physician-induced) bacterial infections develop in association with the use of catheters (tubes) that are inserted into blood vessels. A simple local abscess or a severe endocarditis (inflammation of the lining of the heart) may be the outcome. Staphylococcus aureus (S. aureus), among a variety of aerobic bacteria, accounts for 50 percent of bacterial infections in the blood caused by catheters. Before a bacterium can initiate invasion, adherence must occur to the surface of the catheter or other inanimate surface. The principal point of origin of catheter-related infection is where the device enters the patient's skin. Infection proceeds down the outer surface of the device, ultimately resulting in invasion of the bloodstream. Shortly after insertion, a fibrin sheath begins to develop on the surface of the inserted device. Two strains of S. aureus and a strain of Escherichia coli (E. coli) were used in this study to determine what factors may be involved in the adherence of the bacteria to the surface of inanimate objects. The two strains of staphylococcus showed greater adherence to surfaces that were fibrin coated than to those that were incubated in a buffered salt solution. E. coli, however, showed little or no adherence to any of the catheters. Little is known about the specific mechanisms governing staphylococcal colonization of catheters, but the following three essential factors are known to be involved: the physical and chemical properties of the surface of the catheter; the bacterial surface components that mediate adherence; and the fibrin sheath that coats the surface of the catheter. The specific contributory roles, if any, of fibronectin or vitronectin in supporting the adherence of staphylococci are not clear. However, the data do show that fibrinogen or fibrin mediate the adherence of staphylococci to the surface of catheters. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journal of Infectious Diseases
Emergence of ciprofloxacin-resistant coagulase-negative staphylococcal skin flora in immunocompromised patients receiving ciprofloxacin
Fluoroquinolones (FQs), including ciprofloxacin (CI), are among the most promising new antibiotics; they have broad spectra (ability to kill several different bacteria) that are receiving wide use because of their minimal side effects and good tissue penetration. The possibility of resistant strains of bacteria emerging with such widespread use is a basis for concern. Currently, the only resistance mechanism known in these organisms is chromosomal mutation. High resistance can develop, however, after serial exposure of the organisms to increasing concentrations of FQs. The FQs are indicated for the prophylaxis and treatment of bacterial infections in patients with leukemia and neutropenia (abnormally low numbers of neutrophils, a white blood cell). Shortly after the introduction of FGs in Finland, CI was used for antibacterial prophylaxis in neutropenic leukemia patients. Seven patients developed septicemia, and two died from CI-resistant coagulase negative staphylococci. Was the use of prophylactic CI responsible for the development of resistant strains of bacteria and subsequent septicemia? A study group of 28 leukemia and melanoma patients receiving CI, 31 control patients with cardiovascular or hematologic disease not receiving CI, and 33 staff persons was identified. CI resistance was monitored by culturing and characterizing the coagulase negative staphylococcal skin flora. It was shown that colonization of CI-resistant organisms occurred widely in CI-treated patients, but only occasionally in the control and personnel groups. Plasmid patterns of 91 percent of the bacterial isolates were similar, suggesting epidemiologic association between strains and cross-infection between patients. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Journal of Infectious Diseases
Reinventing phage therapy: Are the parts greater than the sum?
The development of whole phage or bacteriophage as alternative treatment, and the isolation and optimization of purified phage components at antibacterials, which opens new opportunities in the fight against intractable infections, are explored. It concluded that the myriad of antihost phage proteins could be used to map bacterial vulnerabilities that could then serve as targets in novel drug discovery.
Publication Name: Nature Medicine
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