Clonal diversity of Cutibacterium acnes (formerly Propionibacterium acnes) in prosthetic joint infections.

Prosthetic joint infections (PJIs) are rare but feared complications following joint replacement surgery. Cutibacterium acnes is a skin commensal that is best known for its role in acne vulgaris but can also cause invasive infections such as PJIs. Some phylotypes might be associated with specific diseases, and recently, a plasmid was detected that might harbour important virulence genes. In this study, we characterized C. acnes isolates from 63 patients with PJIs (n = 140 isolates) and from the skin of 56 healthy individuals (n = 56 isolates), using molecular methods to determine the phylotype and investigate the presence of the plasmid. Single-locus sequence typing and a polymerase chain reaction designed to detect the plasmid were performed on all 196 isolates. No statistically significant differences in sequence types were seen between the two study groups indicating that the C. acnes that causes PJIs originates from the patients own normal skin microbiota. Of the 27 patients with multiple tissue samples, 19 displayed the same sequence types among all their samples. Single-locus sequence typing identified different genotypes among consecutive C. acnes isolates from four patients with recurrent infections. The plasmid was found among 17 isolates distributed in both groups, indicating that it might not be a marker for virulence regarding PJIs. Patients presenting multiple sequence types in tissue samples may represent contamination or a true polyclonal infection due to C. acnes.

A comparative study of Cutibacterium (Propionibacterium) acnes clones from acne patients and healthy controls.

BACKGROUND: Cutibacterium (Propionibacterium) acnes is assumed to play an important role in the pathogenesis of acne. OBJECTIVES: To examine if clones with distinct virulence properties are associated with acne. METHODS: Multiple C. acnes isolates from follicles and surface skin of patients with moderate to severe acne and healthy controls were characterized by multilocus sequence typing. To determine if CC18 isolates from acne patients differ from those of controls in the possession of virulence genes or lack of genes conducive to a harmonious coexistence the full genomes of dominating CC18 follicular clones from six patients and five controls were sequenced. RESULTS: Individuals carried one to ten clones simultaneously. The dominating C. acnes clones in follicles from acne patients were exclusively from the phylogenetic clade I-1a and all belonged to clonal complex CC18 with the exception of one patient dominated by the worldwide-disseminated and often antibiotic resistant clone ST3. The clonal composition of healthy follicles showed a more heterogeneous pattern with follicles dominated by clones representing the phylogenetic clades I-1a, I-1b, I-2 and II. Comparison of follicular CC18 gene contents, allelic versions of putative virulence genes and their promoter regions, and 54 variable-length intragenic and inter-genic homopolymeric tracts showed extensive conservation and no difference associated with the clinical origin of isolates. CONCLUSIONS: The study supports that C. acnes strains from clonal complex CC18 and the often antibiotic resistant clone ST3 are associated with acne and suggests that susceptibility of the host rather than differences within these clones may determine the clinical outcome of colonization.

Bacterial skin commensals and their role as host guardians.

Recent years' investigations of the co-evolution and functional integration of the human body and its commensal microbiota have disclosed that the microbiome has a major impact on physiological functions including protection against infections, reaction patterns in the immune system, and disposition for inflammation-mediated diseases. Two ubiquitous members of the skin microbiota, the Gram-positive bacteria Staphylococcus epidermidis and Propionibacterium acnes, are predominant on human epithelia and in sebaceous follicles, respectively. Their successful colonisation is a result of a commensal or even mutualistic lifestyle, favouring traits conferring persistency over aggressive host-damaging properties. Some bacterial properties suggest an alliance with the host to keep transient, potential pathogens at bay, such as the ability of S. epidermidis to produce antimicrobials, or the production of short-chain fatty acids by P. acnes. These features can function together with host-derived components of the innate host defence to establish and maintain the composition of a health-associated skin microbiota. However, depending largely on the host status, the relationship between the human host and S. epidermidis/P. acnes can also have parasitic features. Both microorganisms are frequently isolated from opportunistic infections. S. epidermidis is a causative agent of hospital-acquired infections, mostly associated with the use of medical devices. P. acnes is suspected to be of major importance in the pathogenesis of acne and also in a number of other opportunistic infections. In this review we will present bacterial factors and traits of these two key members of our skin microbiota and discuss how they contribute to mutualistic and parasitic properties. The elucidation of their roles in health-promoting or disease-causing processes could lead to new prophylactic and therapeutic strategies against skin disorders and other S. epidermidis/P. acnes-associated diseases, and increase our understanding of the delicate interplay of the skin microbiota with the human host.

Chloroplast DNA phylogeny and biogeography of Lepidium (Brassicaceae).

Two intergenic spacers, trnT-trnL and trnL-trnF, and the trnL intron of cpDNA were sequenced to study phylogenetic relationships and biogeography of 73 Lepidium taxa. Insertions/deletions of ≥3 bp (base pairs) provided reliable phylogenetic information whereas indels ≤2 bp, probably originating from slipped-strand mispairing, are prone to parallelism in the context of our phylogenetic framework. For the first time, an hypothesis of the genus Lepidium is proposed based on molecular phylogeny, in contrast to previous classification schemes into sections and greges (the latter category represents groups of related species within a given geographic region), which are based mainly on fruit characters. Only a few of the taxa as delimited in the traditional systems represent monophyletic lineages. The proposed phylogeny would suggest three main lineages, corresponding to (1) sections Lepia and Cardaria, (2) grex Monoplocoidea from Australia, and (3) remaining taxa, representing the bulk of Lepidium species with more or less resolved sublineages that sometimes represent geographical correspondence. The fossil data, easily dispersible mucilaginous seeds, widespread autogamous breeding systems, and low levels of sequence divergence between species from different continents or islands suggest a rapid radiation of Lepidium by long-distance dispersal in the Pliocene/Pleistocene. As a consequence of climatic changes in this geological epoch, arid/semiarid areas were established, providing favorable conditions for the radiation of Lepidium by which the genus attained its worldwide distribution.

Structure of the F420H2:quinone oxidoreductase of Archaeoglobus fulgidus identification and overproduction of the F420H2-oxidizing subunit.

The F420H2:quinone oxidoreductase from the sulfate-reducing archaeon Archaeoglobus fulgidus is encoded by the fqo gene cluster which comprises 11 genes (fqo J, K, M, L, N, A, BC, D, H, I, F). The last gene of the cluster, fqoF, was overexpressed in Escherichia coli. The purified subunit was able to oxidize reduced cofactor F420 using the electron-acceptor system methyl viologen plus metronidazole. The specific activity at 78 degrees C was 64 micromol F420H2 oxidized. min-1.(mg protein)-1. The purified polypeptide contained 10.6 mol non-heme iron, 7.2 mol acid-labile sulfur and 0.7 mol FAD per mol protein. With the exception of fqoF, the deduced amino-acid sequences of all other genes show homologies to distinct subunits of NADH-quinone oxidoreductases from prokaryotes and eukaryotes. Thus, it is concluded that the F420H2-dependent and the NADH-dependent enzyme are functional equivalents. Both proteins are the initial enzymes of membrane-bound electron-transport systems and are involved in energy conservation. In parallel with bacterial complex I, the F420H2:quinone oxidoreductase may be composed of three subcomplexes. FqoF functions as the input device adjusted to the oxidation of reduced cofactor F420H2, thereby replacing subunits of the input module of complex I that are not present in A. fulgidus. The subunits FqoB, FqoCD and FqoI may form the membrane-associated module and transfer electrons to the membrane-integral module. It is most likely that the last subcomplex is composed of FqoA, FqoH, FqoJ, FqoK, FqoL, FqoM and FqoN. All subunits are highly hydrophobic and are probably involved in the reduction of a special menaquinone with a fully reduced isoprenoid side chain present in the cytoplasmic membrane of A. fulgidus.

Evolutionary Changes in Floral Structure within Lepidium L. (Brassicaceae).

The basic floral ground plan is remarkably constant across Brassicaceae. However, within Lepidium (ca. 175 species), deviations from this ground plan are common, with over half of Lepidium species having only two stamens rather than the usual six and a further eighth of the species having only four stamens. Furthermore, petals are reduced in size in a majority of Lepidium species. In order to determine the frequency and direction of changes in floral structure within Lepidium, we have inferred the phylogeny within the genus from sequences of the internal transcribed spacers of the nuclear ribosomal DNA. On the basis of this inferred phylogeny, we conclude that floral structure within Lepidium is relatively fluid. In order to account for the phylogenetic distributions of the different floral ground plans, at least two independent reductions to the two-stamen condition and at least one reversal to flowers with increased organ numbers are likely to have occurred. To account for the frequency of morphological evolution observed within the genus, we propose that some clades within Lepidium may be predisposed to changes in floral structure. In addition, several transoceanic dispersals are needed to explain the geographic distributions of the clades inferred from the phylogeny.

The use of fluorescent-protein conjugates for staining brain capillaries in hypo- and hyperthermia (26-42 degrees).

The temperature dependency of cerebrocortical capillary diameter (CD), number perfused with fluorescent tracer (CN), and intercapillary distance (ICD) has been investigated for three body temperatures (26, 37, and 42 degrees), in order to analyze the influence of undesired cooling or warming which frequently occurs in animal experiments and humans (freezing, heat disposal, fever, etc.). The capillary bed (Wistar-Frömter rats, N = 92, ketaminxylazin anesthesia) was visualized with a double staining method using serum proteins coupled with either FITC (fluorescein isothiocyanate) or RB-200 (rhodamine-lissamin) injected ia immediately before decapitation. CD (6.1 +/- 0.3 micron, 37 degrees) increased during cooling by about 18%, during warming by about 13%. CN (313 +/- 83/mm2, 37 degrees) showed a 12% increase in response to temperature reduction and 18% after elevation. ICD was characterized by small insignificant changes of the mean values (44.2 +/- 5.5 micron, 37 degrees) at 26 degrees and 42 degrees. Mean cerebrocortical surface PO2 (sPO2) ranging between 15 and 22 mm Hg (37 degrees) increased slightly during warming or decreased during cooling. The sPO2 histogram showed a Gaussian-like shape in the range 0-40 mm Hg at low temperatures (26-34 degrees) and a left-shifted frequency distribution between 34-42 degrees. It was interesting to note that above 38 degrees sporadically high sPO2 values were registered in the range 40-80 mm Hg. Nevertheless, despite pronounced temperature variations, the net effect between O2 transport and consumption was balanced to such an extent that tissue anoxia was not detected within the rat cerebro-cortex.

The influence of moderate hypothermia on cerebral cortex tissue oxygen tension.

The validity of mechanisms balancing oxygen transport and consumption in hypothermia are difficult to analyse because almost any parameter of the transport system is temperature dependent. Two types of experiments have been performed in the rat cerebral cortex to elucidate this problem: PO2 microelectrode study: 32-37 degrees C body temperature, spontaneous respiration. Measurements within the upper tissue layer of 200-500/microgram thickness (N = 15). PO2 surface electrode study: 26-37 degrees C body temperature, artificial respiration. Investigation of the arachnoidal and pial area (N = 46). Mean tissue PO2 (+/- SD) of neo- and archeocortex declined slightly from 27.8 +/- 14.4 mm Hg at 37 degrees C to 25.5 +/- 15.5 mm Hg at 32 degrees C (p less than 0.05, n = 15). Surface PO2 (sPO2) (+/- SD) in response to hypothermia showed a small decrease from 18.1 +/- 4.5 mm Hg (n = 186) at 37 degrees C to 14.7 +/- 4.3 mm Hg (n = 41) at 26 degrees C (p less than 0.05, N = 46). Despite different initial PO2 values at normothermia both groups of experiments are characterized by the same relatively small hypothermia induced PO2 decrease. Oxygen transport and consumption might be balanced under hypothermia and tissue hypoxia does not exist in the temperature range between 26 degrees and 37 degrees C.

[Combined osteosynthesis in experiment and clinic (author's transl)]. / Ergebnisse bei der Verbundosteosynthese in Experiment und Klinik.

Animal experimentations of the pathophysiology of bone union after combined osteosyntheses (plate + methylmethacrylate) showed that acrylic cement destroys the intramedullary blood supply. Revascularization of the cortical bone will occur from the periosteum towards the endosteum. With the stability obtained, the osteotomy heals with formation of callus which overbridges the necrotic bone. Increased soft tissue damage delays callus formation and bone revascularization. In a 9 years period, 327 patients were treated with combined osteosynthesis. 231 of them had an unstable pertrochanteric fracture and 96 were treated because of a pathological fracture. There were 9 soft tissue infections, we observed no osteomyelitis. A follow-up of the patients with pertrochanteric fractures showed 81% good and very good results. If stability was obtained, the fractures used to heal.

[Rescue helicopter services for emergency treatment at the scene of the accident (author's transl)]. / Der Einsatz von Rettungs-hubschraubern zur ärztlichen Erstversorgung am Notfallort.

During the last three years 3639 emergencies were dealt with using the rescue helicopter "Christoph 4" in Hannover. Of these, 89.3% were primary flights to the scene of the accident to give qualified first aid by a medical team. The average distance to the scene of the accident was 20.8 km with an average flight time of 8.5 min. 2688 patients were treated by the helicopter crew. 89.8% of the patients had injuries of a severity of NACA (National Commitee for Aeronautics) 3 and more. Intubation and artificial respiration was carried out on 293 occasions. Shock treatment with blood substitute was given in 1593 cases. 30 resuscitations at the scene of the accident were successful.