The prevalence of imipenem resistance among Pseudomonas aeruginosa isolates at a 195-bed tertiary care medical center in Cali, Colombia, rose from 2% in 1996 to 28% in 1997 and to over 40% in 2003. Many isolates showed high-level multiresistance, and phenotypic characterization suggested the spread of a predominant strain with minor variants. Sixty-six resistant isolates collected between February 1999 and July 2003 from hospitalized patients (n ‫؍‬ 54) and environmental samples (n ‫؍‬ 12) were subjected to a fuller analysis. Genetic fingerprints were compared by pulsed-field gel electrophoresis (PFGE) of SpeI-digested genomic DNA, and bla IMP and bla VIM genes were sought by PCR. PFGE and serotyping indicated that 52 of the 66 isolates belonged to a single strain, with 82% similarity; the PFGE pattern for this organism was designated pattern A. Two further pairs of isolates represented single strains; the remaining nine isolates were unique, and in the case of one isolate, no satisfactory PFGE profile could be obtained. The pattern A isolates were mostly of serotype O12 and were highly resistant to imipenem (MICs, 32 to >256 g/ml), with this resistance decreased eightfold or more in the presence of EDTA. They yielded amplicons with bla VIM -specific primers, and sequencing of DNA from a representative isolate revealed bla VIM-8 , a novel allele with three polymorphisms compared with the sequence of bla VIM-2 . Two of these nucleotide changes were silent, but the third determined a Thr139Ala substitution. Only 4 of 13 resistant isolates (2 clinical isolates and 2 environmental isolates) assigned to other PFGE types carried bla VIM alleles, whereas the others were less multiresistant and mostly had lower levels of imipenem resistance (MICs, <32 g/ml) which was not significantly reduced by EDTA. No bla IMP alleles were detected. During 2003, when the environmental study was undertaken, serotype O12 isolates with bla VIM were recovered from sinks and stethoscopes in the most-affected units, although not from the hands of staff; the problem declined once these reservoirs were disinfected and hygienic precautions were reinforced.

During a study on the occurrence of Malassezia spp. in 112 animals (50 horses, 25 goats, 25 sheep and 12 cows), Malassezia spp. were isolated from 60% of horses, 28% of sheep, 44% of goats and 58% of cows. In these animals, the occurrence of lipid-dependent species (42%) was much greater than the occurrence observed for M. pachydermatis (3%). Among the results obtained, we point out the first isolation of M. sympodialis, M. globosa and M. restricta from sheep, M. pachydermatis, M. furfur, M. sympodialis, M. obtusa, M. globosa and M. restricta from goats and M. furfur, M. slooffiae, M. obtusa, M. globosa and M. restricta from horses. To the authors' knowledge, this survey also states the first description of the presence of M. restricta in animals.

The lipid-dependent species Malassezia sympodialis was isolated from two cats with otitis externa. To our knowledge, this is the first report of the isolation of lipid-dependent species of the genus Malassezia associated with skin disease in domestic animals.

During a survey of the occurrence of Malassezia species in the external ear canals of cats without otitis externa,Malassezia furfur was isolated. This is the first report of the isolation of M. furfur from cats.

Freezing at −80°C, lyophilization, preservation in distilled water, and storage in different culture media were performed in order to find a suitable method that allowed a prolonged storage ofMalassezia spp. Freezing at −80°C was the only method successful at maintaining all species.