Articles: bacteria.
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The bacterial flora of chronic venous ulcers treated with an occlusive hydrocolloid dressing were studied over a period of 8 weeks. A novel exudate sampling method was used in an attempt to isolate anaerobic bacteria. ⋯ Once a species was present, it remained with the exception of Pseudomonas, which appeared to be inhibited by the dressing. Twelve out of 20 ulcers contained anaerobic bacteria and healing did not appear to be impaired by the presence of any particular species of bacteria.
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Colonization of the oropharynx with potentially pathogenic microorganisms (PPM) is a highly significant factor in the pathogenesis of bacterial pneumonia in intensive care patients. Via colonization of the oropharynx, bacteria pass into the tracheobronchial tree, where they can give rise to pneumonia after overcoming pulmonary resistance mechanisms. By a new, prophylactic antibiotic treatment schedule consisting in selective decontamination of the digestive tract (SDD) with locally applied nonabsorbable antibiotics, Stoutenbeek achieved drastic lowering of the colonization and infection rate in trauma patients. ⋯ The SDD schedule proved to be effective with regard to the rate of infection. In the control group, 35 patients developed pneumonia (42%) as against 5 patients receiving SDD prophylaxis (6%). The duration of mechanical ventilation in the patients with pneumonia was 5 days longer than in patients without pneumonia.(ABSTRACT TRUNCATED AT 400 WORDS)
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Oral Surg. Oral Med. Oral Pathol. · Feb 1989
Randomized Controlled Trial Clinical TrialEffect of chlorhexidine rinsing on the oropharyngeal ecology in patients with head and neck cancer who have irradiation mucositis.
Oral flora is thought to contribute to irradiation mucositis in patients with head and neck cancer. Neglect of oral hygienic care may also contribute to mucositis. The purpose of this prospective, randomized, placebo-controlled, double-blind study was to evaluate the effect of chlorhexidine 0.1% mouthrinses on oral flora and irradiation mucositis. ⋯ The colonization patterns of Candida species, Streptococcus faecalis, staphylococci, and Enterobacteriaceae, Pseudomonadaceae, and Acinetobacter species were not influenced by 5 weeks of use of chlorhexidine rinses when compared with the placebo. No differences were seen between the two study groups in the development and severity of mucositis. In conclusion, suppression of oral flora and a lowering of the severity of mucositis by means of disinfecting mouthrinses were not successful.
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Coughing, sneezing, talking, bed-making, turning pages of books, etc. all generate microbial aerosols which are carried and dispersed by air movements. Inhalation of these particles may cause allergic responses but whether or not infectious disease ensues depends in part on the viability and infectivity of the inhaled microbes and their landing sites. Desiccation is experienced by all airborne microbes; gram-negative bacteria and lipid-containing viruses demonstrate phase changes in their outer phospholipid bilayer membranes owing to concomitant changes in water content and/or temperature. ⋯ Radiation, oxygen, ozone and its reaction products and various pollutants also decrease viability and infectivity through chemical, physical and biological modification to phospholipid, protein and nucleic acid moieties. The extent of damage and the degree of repair together with the efficacy of host defence mechanisms largely controls whether the causative microbes take hold and spread disease via the airborne route. At least indoors, where desiccation is the predominant stress, the general reversibility of membrane-phase changes by vapour-phase rehydration when coupled with efficacious microbial enzymatic repair mechanisms under genetic control, virtually ensures the spread of disease by the aerobiological pathway.
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The correlation between in vitro activity, pharmacokinetic properties and effect in vivo of antibiotics has so far received relatively little attention, and the optimal dosing strategy for most antibiotics is still a matter of dispute. A review on this subject is presented based on observations from an experimental pneumococcus infection model in mice. The pneumococcus is particularly suitable as pathogen in experimental infection models for antibiotic research, since it is clinically relevant, susceptible to a range of antibiotics, and naturally virulent to most laboratory animals without the need for potentiating factors. ⋯ The role of the time greater than MIC in context with other factors such as extravascular penetration of antibiotics, serum protein binding and the post-antibiotic effect is discussed. Most other experimental studies concerning dosing strategy for the beta-lactam antibiotics, including the few clinical studies available, confirm the importance of the time factor. The clinical implication for this group of antibiotics therefore is to strive for a constant, not necessarily high, concentration above the MIC.(ABSTRACT TRUNCATED AT 400 WORDS)