In vitro antibacterial activity of concentrated polyethylene glycol 400 solutions

Efficacy of mupirocin in methicillin-resistant Staphylococcus aureus burn wound infection

Methicillin-resistant Staphylococcus aureus strains (MRSA) have become increasingly prevalent as nosocomial pathogens, especially in burn wounds. MRSA constituted 38% of all S. aureus isolates in our 25-bed burns unit despite the utilization of a combination of 1% silver sulfadiazine and 0.2% chlorhexidine as topical therapy. Mupirocin, a new antibiotic, has proved in vitro and in vivo to be highly effective in the treatment of MRSA infections. A prospective clinical trial with mupirocin ointment in MRSA burn wound infection was untertaken. Forty-five children with 59 discrete burn wounds and from whom MRSA were isolated were treated with 2% mupirocin ointment under occlusive dressings, applied twice daily for 5 days. The average burned area treated was 8% (range, 2 to 20%) of the total body surface area. The burn wounds were assessed clinically and bacteriologically daily. Mupirocin eliminated MRSA in all 59 wounds treated, with the maximum therapeutic response seen within 4 days. In three wounds, gram-negative organisms persisted after 5 days of topical therapy. Treatment was well tolerated by all children. We recommend that mupirocin in its present polyethylene glycol base should be used only on a selective basis, when current prophylactic topical therapy has failed to control MRSA infection in burns of less than 20% of the total body surface area, and that it should be applied only for a limited period of 5 days. The safety and the efficacy of mupirocin in burns exceeding 20% of the total body surface area need to be established.

Impetigo contagiosa III. Comparative efficacy of oral erythromycin and topical mupirocin

Ninety-seven patients with impetigo were prospectively enrolled in a study to determine the comparative efficacy of systemic and topical antibiotic therapy. After obtaining a bacterial culture from a representative lesion, the children were randomized to receive seven days of either oral erythromycin or topical mupirocin administered three times daily. Staphylococcus aureus alone was isolated from 51% and in association with group A beta-hemolytic streptococci (GABS) from 29%; GABS alone was isolated from 4% of patients. Of 48 children who received erythromycin, 43 (90%) were clinically improved or cured, and 11 of 17 were bacteriologically cured. Of 49 children who received mupirocin, 47 (96%) were clinically improved or cured, and 10 of 14 were bacteriologically cured. At three-week follow-up, clinical cure rates and number of secondary household cases of impetigo were equivalent in both treatment groups. Mupirocin appears to be a well-tolerated, albeit expensive, alternative to erythromycin for the treatment of impetigo.

Effect of polyethylene glycol 400 on adriamycin induced histamine release

The activity of polyethylene glycol 400, a widely used drug solvent, was tested on the release of histamine induced by adriamycin in vitro on peritoneal rat mast cells and in vivo in a mouse model. Preincubation of mast cells with high (10 and 5%) concentrations of polyethylene glycol 400 significantly inhibited the important histamine release induced by 100 micrograms/ml of adriamycin; furthermore, polyethylene glycol 400 (3.45 g/kg; 0.345 g/ml) pretreatment almost completely abolished the peritoneal and pericardial mast cell degranulation and the cardiac toxicity caused by an intraperitoneal injection of 15 mg/kg of adriamycin. This effect of polyethylene glycol 400 on adriamycin-induced histamine release could explain the protective action exhibited in vivo on adriamycin treated animals, therefore confirming that adriamycin cardiotoxicity could be related to the release of histamine and other vasoactive substances.

Submicroscopical changes in Klebsiella pneumoniae cells treated with concentrated sucrose and polyethylene glycol 400 solutions

This study reports the extent and character of plasmolysis and other morphological changes as shown by electron microscopy in a strain of Klebsiella pneumoniae and with sucrose or polyethylene glycol 400 (PEG-400) as the plasmolysing agent at a water activity of 0.935. Both solutes produced severe plasmolysis in K. pneumoniae cells; PEG-400 also caused some cell wall collapse and finger like extrusions to emerge from the bacterial cell.