Pneumonia caused by coliforms and Pseudomonas aeruginosa.

Abstract

NW3soNopsis The diagnosis and treatment of 20 hospital patients seen in the past year with proven pneumonia caused by coliforms and Pseudomonas aeruginosa are discussed. Predisposing factors and methods for improving laboratory and clinical diagnosis are analysed, the main problem being to discriminate between genuine pneumonia caused by these organisms and mere contamination of sputum samples resulting from colonization of the upper respiratory tract following broad-spectrum chemotherapy.Overall initial chemotherapy with gentamicin cured 75% (15 out of 20) of the patients in spite of unfavourable underlying pathology. Where gentamicin was given in adequate dosage, which in practice meant that dose which produced peak serum concentrations of 8 ,ug/ml or more, the cure rate was 91% (11 out of 12). In those patients achieving (measured) peak serum concentrations of less than 8 ,ug/ml the cure rate was only 33% (4 out of 12). These figures include four patients who failed to respond to doses of gentamicin producing peak concentrations of 5-0-6-0 ,ug/ml in each case. These patients responded promptly to higher doses (or accumulation), producing peak serum concentrations of 8 ,ug/ml or more and were then cured within three to five days.Toxicity from gentamicin was not observed in any patient. These results indicate that it is necessary to monitor gentamicin therapy by laboratory assay to ensure adequate dosage and that peak serum concentrations of 8 ,ug/ml or more are significantly correlated with successful treatment ofpneumonia caused by coliforms and Ps. aeruginosa.

In vivo efficacy of humanised intermittent versus continuous ceftazidime in combination with tobramycin in an experimental model of pseudomonal pneumonia

“…Furthermore, the model used [22] was very close to human pseudomonal pneumonia, especially with regard to bacterial concentration [23][24][25][26][27][28][29][30][31], and was also close to the human therapeutic situation since human-like pharmacokinetics was successfully achieved. In these conditions, we found that continuous infusion of CAZ with or without TOB was the most effective regimen.…”

A Model for Dosing Gentamicin in Children and Adolescents that Adjusts for Tissue Accumulation with Continuous Dosing1

“…Early and accurate escalation of gentamicin doses may be clinically important in children with serious Gram-negativeinfections, particularly Gram-negative pneumonia for which serum concentrations greater than 8J.lg/ ml are optimal (Darrell et al, 1967;Noone et al, 1976Noone et al, , 1978. The new model provides a simple and more accurate method for individualising paediatric and adolescent doses within the first few hours of therapy.…”

“…Peak serum concentrations higher than 4 to 5J.lg/ml (Darrell and Waterworth, 1967; Jackson and Riff, 1971;Nooneetal., 1974Nooneetal., , 1978are Age (years) considered optimal for treatment of serious Gramnegative infections, with concentrations greater than 8]Jg/ml (Noone and Rogers, 1976;Noone et aI., 1978) desirable for Gram-negative pneumonia. On the other hand, concentrations greater than 12J.lg/ml are not recommended because of the increased risk of ototoxicity (Hewitt, 1973;Jackson and A'reieri, 1971;Wersall et al, 1969) while nadir (pre-dose) concentrations exceeding 2 J.lg / ml appear to increase the risk of nephrotoxicity (Dahlgren et aI., 1975;Goodman et al, 1974).…”

Role of Pharmacokinetics and Pharmacodynamics: Does the Dose Matter?

“…When aerobic, gram-negative rods that cause urinary tract infection, skin and soft-tissue infection, or bacteremia were treated with gentamicin, a post-dose concentration of 15 mg/L given in the first 3 days of therapy was related to a good response. In patients with pneumonia caused by gram-negative rods, post-dose concentrations of 18 mg/L were related to beneficial outcome [5][6][7].…”