Articles: bacteria.
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Catheter-related sepsis is one of the major complications of total parenteral nutrition (TPN) therapy. The relationship between microbial colonization of the skin at the site of catheter insertion and colonization of the central venous catheter was investigated in 74 catheters used to administer TPN therapy in 53 patients. Semiquantitative culture specimens were obtained from the insertion site and intravascular and subcutaneous catheter segments at the time of catheter removal. ⋯ The association between colonization of catheters and the presence of more than 10(3) bacterial or fungal colony-forming units at the insertion site was significant (P less than 0.005). These results demonstrated that colonization of catheters by organisms present on the skin at the site of catheter insertion occurred twice as frequently as colonization by the hematogenous route. The results also suggested that colonization of catheters by organisms present at the insertion site occurred only after a threshold number of organisms was reached.
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The Journal of hygiene · Aug 1982
Hand carriage of aerobic Gram-negative rods by health care personnel.
A quantitative culture technique (hand washed in a glove containing broth for 30 s) was used to determine the frequency of hand carriage of aerobic Gram-negative rods by various groups of health care workers and 104 control subjects. Overall, 31% of health care workers carried aerobic Gram-negative rods on their hands compared to 59% of control subjects (P < 0.001). ⋯ We conclude that endemic hand carriage of aerobic Gram-negative rods by health care personnel is common, but significantly less than that of control subjects. Enterobacter agglomerans is found so frequently on the hands of control subjects that it must be considered part of the normal hand flora.
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The ability of total parenteral nutrition (TPN) solutions containing albumin to support bacterial and fungal growth was studied. The following solutions were tested for microbial growth: (A) thioglycolate broth, (B) solution A with preservatives, (C) albumin 6.25 g in 500 ml 0.9% sodium chloride injections, (D) solution C with preservatives, (E) amino acid and dextrose TPN solution with magnesium sulfate and folic acid, (F) solution E with albumin 6.25 g in 500 ml, (G) amino acid and dextrose TPN solution with calcium gluconate and multivitamins, and (H) solution G with albumin 6.25 g in 500 ml. Each solution was inoculated with 1 X 10(5) bacteria/ml or 1 X 10(3) yeast/ml in 12 serial dilutions using minimum inhibitory concentration (MIC) plates. ⋯ The presence of albumin had no effect on the growth of S. faecalis or Ps. aeruginosa. The addition of albumin to crystalline amino acid TPN solutions increases the potential of these solutions to support the growth of fungi and bacteria. Hence, it is recommended that albumin be administered separate from amino acid TPN solutions.
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Appl. Environ. Microbiol. · Dec 1981
Kinetic explanation for accumulation of nitrite, nitric oxide, and nitrous oxide during bacterial denitrification.
The kinetics of denitrification and the causes of nitrite and nitrous oxide accumulation were examined in resting cell suspensions of three denitrifiers. An Alcaligenes species and a Pseudomonas fluorescens isolate characteristically accumulated nitrite when reducing nitrate; a Flavobacterium isolate did not. Nitrate did not inhibit nitrite reduction in cultures grown with tungstate to prevent formation of an active nitrate reductase; rather, accumulation of nitrite seemed to depend on the relative rates of nitrate and nitrite reduction. ⋯ However, all three isolates produced higher ratios of nitrous oxide to dinitrogen as the oxygen tension increased. Inclusion of oxygen in the model as a nonspecific inhibitor of each step in denitrification resulted in decreased gas production but increased ratios of nitrous oxide to dinitrogen, as observed experimentally. The simplicity of this kinetic model of denitrification and its ability to unify disparate observations should make the model a useful guide in research on the physiology of denitrifier response to environmental effectors.