We present the first clinical report of a Staphylococcus pseudintermedius infection in a human. Biochemically, S. pseudintermedius can be easily misidentified as S. aureus. Therefore, the final microbiological identification requires the combination of phenotypic and genotypic tests. CASE REPORTA 60-year-old male patient was referred to our center because of ischemic cardiomyopathy and ventricle tachycardia, for which he had received an implantable cardioverter-defibrillator (ICD) in January 2004. In addition, his medical history comprised arterial hypertension, hypercholesterolemia, and a prostate carcinoma. In August 2005, he presented with complaints of migration of the ICD device. No other symptoms of note were elicited. The patient was hemodynamically stable and afebrile (body temperature of 36.7°C). Hematological investigations revealed a hemoglobin level and platelet and leukocyte counts within the normal ranges. His C-reactive protein level was slightly increased, at 1.61 mg/liter (normal, 0 to 5 mg/liter). Clinical examination revealed a perforation of the ICD pocket. Infection was suspected by the presence of pus in the eroded pocket. The infected ICD was surgically removed, and several samples (the ventricular lead, pus, and a tissue sample from the pocket) were sent for culture.Gram staining of the pus showed gram-positive cocci. The specimens were plated onto sheep blood agar (BioMérieux, Benelux S.A./N.V.) and chocolate agar (BioMérieux), both incubated at 37°C in air supplemented with 5% CO 2 , and mannitol salt lipovitellinase agar (homemade), MacConkey agar (BioMérieux), and D-Coccosel agar (BioMérieux), all incubated at 37°C in air. In addition, thioglycolate broth (BD, Belgium) was inoculated and incubated at 37°C in air.

Cystic fibrosis is a frequent autosomal recessive disorder that is caused by the malfunctioning of a small chloride channel, the cystic fibrosis transmembrane conductance regulator. The protein is found in the apical membrane of epithelial cells lining exocrine glands. Absence of this channel results in imbalance of ion concentrations across the cell membrane. As a result, fluids secreted through these glands become more viscous and, in the end, ducts become plugged and atrophic. Little is known about the pathways that link the malfunctioning of the CFTR protein with the observed clinical phenotype. Moreover, there is no strict correlation between specific CFTR mutations and the CF phenotype. This might be explained by the fact that environmental and additional genetic factors may influence the phenotype. The CFTR protein itself is regulated at the maturational level by chaperones and SNARE proteins and at the functional level by several protein kinases. Moreover, CFTR functions also as a regulator of other ion channels and of intracellular membrane transport processes. In order to be able to function as a protein with pleiotropic actions, CFTR seems to be linked with other proteins and with the cytoskeleton through interaction with PDZ-domain-containing proteins at the apical pole of the cell. Progress in cystic fibrosis research is substantial, but still leaves many questions unanswered.

The results suggest that a correlation can be found in diseased oral epithelium between the defensin profiles that are induced and the pathogenicity of the oral bacterial strains.

In order to get a better insight into the function of amino acid residues located in the second transmembrane domain of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, all exon 18 mutations found in cystic fibrosis (CF) patients were characterized at the protein and at the electrophysiological level. Of the different mutations present in transmembrane helix 12 (M1137V, M1137R, I1139V and v vM1140), and the intracytoplasmic loop connecting TM12 and NBD2 (D1152H and D1154G), only M1137R interfered with the proper maturation of the protein. Permeability studies performed after injection of the different wild-type and mutant cRNAs in Xenopus laevis oocytes indicated that the mutations did not alter the permeability sequence of the CFTR channels. The whole cell cAMP activated chloride currents, however, were significantly reduced for M1137V, I1139V, D1152H and D1154G and close to zero for v vM1140, indicating that these mutations interfere with the proper gating of the chloride channels.z 1998 Federation of European Biochemical Societies.

In order to gain a better insight into the structure and function of the regulatory domain (RD) of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, 19 RD missense mutations that had been identified in patients were functionally characterized. Nine of these (I601F, L610S, A613T, D614G, I618T, L619S, H620P, G628R and L633P) resulted in aberrant processing. No or a very small number of functional CFTR proteins will therefore appear at the cell membrane in cells expressing these mutants. These mutations were clustered in the N-terminal part of the RD, suggesting that this subdomain has a folding pattern that is very sensitive to amino acid changes. Mutations that caused no aberrant processing were further characterized at the electrophysiological level. First, they were studied at the whole cell level in Xenopus laevis oocytes. Mutants that induced a whole cell current that was significantly different from wild-type CFTR were subsequently analysed at the single channel level in COS1 cells transiently expressing the different mutant and wild-type proteins. Three mutant chloride channels, G622D, R792G and E822K CFTR, were characterized by significantly lower intrinsic chloride channel activities compared with wild-type CFTR. Two mutations, H620Q and A800G, resulted in increased intrinsic chloride transport activities. Finally, T665S and E826K CFTR had single channel properties not significantly different from wild-type CFTR.