Serum bactericidal activity of three different dosing regimens of colistin with implications for optimum clinical use.

Although colistin methanesulfonate (CMS) has been used extensively in critically ill patients infected with multidrug-resistant organisms, the optimum dosing regimen remains to be determined. Herein, we examined the pharmacokinetics of three different dosing regimens of CMS, 3 million units every 8 h (regimen A), 4.5 million units every 12 h (regimen B), 9 million units every 24 h (regimen C) and evaluated the bactericidal activity of serum containing various concentrations of colistin against Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) of 1 microg/ml. the means +/- SE serum C(max )of colistin for regimens A, B, and C were 3.34+/-0.35, 2.98+/-0.27, and 5.63+/-0.87 microg/ml, respectively. All serum samples containing colistin >4 microg/ml (serum concentration/MIC >4) eliminated P. aeruginosa whereas only 40% of samples containing colistin <4 microg/ml resulted in complete bacterial killing. these findings indicate that the currently used dosing regimens might not provide the most effective therapy with CMS and justify administering larger dosages in longer intervals.

Disseminated zygomycosis with involvement of the central nervous system.

Zygomycosis of the central nervous system (CNS) can manifest in three distinct clinical forms, as rhinocerebral zygomycosis, as disseminated zygomycosis with CNS involvement, and as isolated cerebral zygomycosis. We present a case of a 2-year-old boy with leukaemia and disseminated zygomycosis, caused by Absidia corymbifera, involving the brain, spinal cord, lung and liver. The child received treatment with liposomal amphotericin B and posaconazole for 6 months. Although the lesions of the lungs and liver resolved, those of the CNS persisted and the child is in a vegetative state. A review of the literature after 2004 identified ten additional cases of disseminated zygomycosis with cerebral involvement, all but one of which had concurrent lung infection. The most common underlying disease in these cases was haematological malignancy and the mortality rate was 70%. Disseminated zygomycosis with cerebral involvement is a fatal disease. Early recognition and prompt intervention with combined medical and surgical treatment may improve the outcome.

First cluster of vancomycin-resistant Enterococcus faecalis isolates in Cyprus.

This report describes the first patient in Cyprus to be infected with a vancomycin-resistant enterococcus, as well as the microbiological characteristics of a cluster of vancomycin-resistant enterococcus isolates from the intensive care unit where the index case was hospitalised. All isolates were identified as Enterococcus faecalis, belonged to the same clone, and contained the vanA gene cluster. Transfer of glycopeptide resistance to a susceptible strain of E. faecalis could not be detected.