On the target of a novel class of antibiotics, oxazolidinones, active against multidrug-resistant Gram-positive bacteria.

Oxazolidinones are a promising new class of synthetic antibiotics active against multidrug-resistant Gram-positive bacteria. To elucidate their mode of action, the effect of DuP 721 on individual steps of protein translation was studied. The drug does not interfere with translation initiation at the stage of mRNA binding or formation of 30S pre-initiation complexes. However, it inhibits the puromycin-mediated release of [35S]formyl-methionine from 70S initiation complexes in a dose-dependent manner. Inhibition involves binding of the oxazolidinone to the large ribosomal subunit and is twice as high with 50S subunits from Gram-positive as with those from Gram-negative bacteria.

Hospital infestation by the cluster fly, Pollenia rudis sensu stricto Fabricius 1794 (Diptera: Calliphoridae), and its possible role in transmission of bacterial pathogens in Germany.

The potential of the cluster fly, Pollenia rudis sensu stricto, to transmit bacterial pathogens was investigated during a mass infestation that took place in a German hospital. Cluster flies were individually examined for mesophilic bacteria carried on the exoskeleton. Bacterial growth could only be detected by using the enrichment culture technique to increase sensitivity, but not by direct intoculation of fly samples to agar plates. All 50 cluster fly samples that were tested carried opportunistic aerobic mesophilic Bacillus spp., whereas 41 fly samples were positive for Erwinia spp., 16 samples for Erwinia amylovara, 24 samples for Stenotrophomonas maltophilia, and 4 samples for Flavobacterium odoratum. Staphylococcus lugdunensis and Pseudomonas aeruginosa were found in 5 samples. No bacteriologically sterile cluster fly samples were obtained. The whole bacterial pattern found on P. rudis s. s. is known for its potential to cause opportunistic and/or nosocomial infections in humans. The results obtained led to the assumption that mass infestations of cluster flies occurring in sensitive areas, especially in hospitals, may cause a low, but not neglectable health threat due to mechanical transmission of bacterial pathogens.

Natural inhibitors of germination and growth, VII synthesis of ribulosebisphosphate carboxylase in darkness and its inhibition by coumarin.

Cress (Lepidium sativum) seeds were germinated in darkness. Seedlings were investigated for soluble proteins by SDS-PAGE. Two proteins were identified by microsequencing: the small subunit of ribulosebisphosphate carboxylase (SSU) and the alpha subunit of the storage protein cruciferin. Net synthesis of small and large subunits of ribulosebisphosphate carboxylase (SSU and LSU) was investigated by Western blot. Net synthesis of both subunits was inhibited by coumarin. To the contrary, net synthesis of cruciferin was increased by coumarin. With specific cDNA probes, we determined steady state levels of the corresponding mRNAs (rbcS mRNA for SSU, rbcL mRNA for LSU). Both mRNAs can be detected in dry seeds; their amount increases during germination in the dark. Incubation with coumarin inhibits this increase. Inhibition of development by coumarin on the level of transcription is discussed.

[Acanthamoeba, naturally intracellularly infected with Pseudomonas aeruginosa, after their isolation from a microbiologically contaminated drinking water system in a hospital]. / Natürliche intrazelluläre Infektionen bei Acanthamoeben mit Pseudomonas aeruginosa nach ihrer Isolierung aus einer mikrobiologisch beanstandeten Trinkwasser-Hausinstallation eines Krankenhauses.

The drinking water system of a new hospital building that was highly contaminated with bacteria before opening was investigated too for the prevalence of small free living amoebae. Germ counts resulted in > 100 CFU/ml in 100% of the cold water samples, that showed also growth of P. aeruginosa, whereas E. coli and coliforme bacteria could not be identified. The investigation of 37 water samples for protozoa revealed growth of small freeliving amoebae in 20 samples (54%) belonging to 10 species of the genus Acanthamoeba, Naegleria, Hartmannella, Echinamoeba among others. In addition 2 Ciliate- and 2 Microflagellate-species could be observed. While all Naegleria strains isolated belonged to the N. gruberi-complex two of 16 Acanthamoeba-isolates proved to be pathogenic for laboratory mice. From 7 watersamples positive with P. aeruginosa 5 Acanthamoeba- and 2 Echinamoeba strains could be isolated which revealed intracellular multiplication of P. aeruginosa. Because of their well known resistances against chlorine, the amoebae and their cysts are considered to be vectors for these intracellular bacteria. A complete sanitation of the incriminated drinking water system was accomplished by combined chemical and thermic disinfection measures.

Sick building syndrome in an office building formerly used by a pharmaceutical company: a case study.

In the past two decades, a group of health problems related to the indoor environment--generally termed sick building syndrome (SBS)--has emerged. We present an investigation of SBS in employees of a ministry working in a naturally ventilated office building that formerly had been used by a pharmaceutical company. A preceding environmental monitoring had failed to identify the cause(s) for the complaints. We conducted a questionnaire-based investigation and categorized the building sections and rooms according to their renovation status and their former use, respectively. The highest level of complaints was found among the employees working in rooms that in the past had been used for the production or storage of various pharmaceutical products suggesting that pharmaceutical odors may be a risk factor for SBS. Clinical laboratory tests did not show any unusual results. We conclude that the former use of a building for production and storage of pharmaceutical products should be considered as a possible risk factor for complaints about indoor air quality, e.g., when advising about or planning for renovations of buildings formerly used for production, handling, or storing of chemicals.