Effect of aerosolized colistin on multidrug-resistant Pseudomonas aeruginosa in bronchial secretions of patients without cystic fibrosis.

We performed a limited microbiological study to examine the effect of aerosolized colistin (1 million international units every 8 hours) on the colonization of the respiratory tract with Pseudomonas aeruginosa of five intubated, mechanically ventilated patients in the Intensive Care Unit (ICU). No adverse or side effects of the administered aerosolized colistin were reported. The microbial counts of Pseudomonas aeruginosa prior to the use of aerosolized colistin, as well as during the second, fourth, sixth, and eighth day after the use of the drug were measured. The results of this preliminary study suggest that aerosolized colistin was effective in reducing quickly the microbial counts and eliminating microbial growth of Pseudomonas aeruginosa by the sixth day of use in all studied patients.

Subtyping and antifungal susceptibilities of Candida spp. in the intensive care unit of a Greek general hospital.

This study identified the Candida spp., susceptibility to antifungal agents and the prevailing Candida albicans subtypes responsible for infections or colonization of 42 patients in the ICU over a 6-month period. Most isolates were C. albicans (66.1%) and Candida tropicalis (28.3%) all of which were susceptible in vitro to antifungal agents. Subtypes of the C. albicans isolates were identified by pulsed field gel electrophoresis Sfi I chromosomal digests. Two major C. albicans subtypes were identified, whereas subtype heterogeneity was found among strains of Candida glabrata and C. tropicalis. Sfi I PFGE restriction patterns were able to discriminate between sub-populations of C. albicans isolates, clustering them into distinct, epidemiologically congruous groups.

Comparison of in vitro activities of eight new beta-lactam compounds against cephalothin-resistant Enterobacteriaceae from hospital patients.

The in vitro antibacterial activity of eight newer beta-lactam antibiotics (mecillinam, piperacillin, mezlocillin, cefoxitin, cefotaxime, moxalactam, ceftriaxone and ceftazidime) was determined against 87 cephalothin-resistant strains of Enterobacteriaceae isolated during 6 months in a general hospital. Ceftriaxone, cefotaxime, moxalactam and ceftazidime proved to be highly active; only a minority of strains required higher concentrations than 0.125 microgram/ml for inhibition of growth. Cefoxitin, mecillinam, mezlocillin and piperacillin were less active. Mecillinam displayed greater efficacy against Escherichia coli, Klebsiella and Enterobacter spp., while the same was the case for piperacillin against Proteus mirabilis and Serratia marcescens, and for cefoxitin against indole-positive Proteus spp. The production of beta-lactamase was correlated with a reduced activity of mecillinam, mezlocillin and piperacillin but not of cefoxitin or the other beta-lactamase-stable cephalosporins. However, some strains, mainly those of Proteus, Enterobacter and Serratia, though resistant to mecillinam, mezlocillin and piperacillin did not produce beta-lactamases. This observation might indicate that ceftriaxone, moxalactam, cefotaxime and ceftazidime, besides their indifference to beta-lactamases, are characterized also by a high degree of intrinsic activity.