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A Miele

Publications and source records attributed to A Miele.

12 recordsLinked to original sources
PubMed2000

Crystallization and preliminary X-ray diffraction studies of a monooxygenase from Streptomyces coelicolor A3(2) involved in the biosynthesis of the polyketide actinorhodin.

The aromatic monooxygenase ActVA-Orf6 from Streptomyces coelicolor A3(2) that catalyses an unusual oxidation on the actinorhodin biosynthetic pathway has been crystallized. The crystals diffract to 1.73 A and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 46.95, b = 59.29, c = 71.67 A. Solvent-content (44%) and self-rotation function calculations predict the presence of two molecules in the asymmetric unit. Structure determination should provide further insight into the enzyme mechanism and aid in the design of biosynthetic pathways to produce new polyketide natural products with novel functionality.

Anthraquinones↗
PubMed1996

In vitro conjugative transfer of VanA vancomycin resistance between Enterococci and Listeriae of different species.

In a study designed to gain data on the in vitro transferability of vancomycin resistance from enterococci of the VanA phenotype to listeriae of different species, three clinical Enterococcus isolates-Enterococcus faecium LS10, Enterococcus faecalis LS4, and Enterococcus faecalis A3208, all harboring a plasmid that strongly hybridized with a vanA probe-were used as donors in transfer experiments. Strains of five Listeria species were used as recipients. From Enterococcus faecium LS10, glycopeptide resistance was transferred to Listeria monocytogenes, Listeria ivanovii, and Listeria welshimeri recipients, whereas no transfer occurred to Listeria seeligeri or Listeria innocua strains. From the two Enterococcus faecalis isolates, no transfer occurred to any Listeria recipient. MICs of both vancomycin and teicoplanin were > or = 256 mg/l for all transconjugants tested. Furthermore, all transconjugants harbored a plasmid that strongly hybridized with the vanA probe, with vanA consistently located in an EcoRI fragment of about 4 kb. Exposure of Listeria transconjugants to vancomycin resulted in synthesis of a membrane protein similar in size (39 kDa) to a vancomycin-induced membrane protein of Enterococcus faecium LS10. In retransfer experiments with Listeria transconjugants used as donors, glycopeptide resistance was transferred to all Listeria recipients tested, including strains of Listeria innocua and Listeria seeligeri, which were unable to receive the resistance from Enterococcus faecium LS10. The frequency of vanA transfer to listerial recipients was greater in retransfer experiments than in the primary matings. These findings suggest that the vanA resistance determinant might spread to the established pathogen Listeria monocytogenes, both directly from a resistant enterococcus and through strains of nonpathogenic Listeria species acting as intermediate resistance vehicles.

Anti-Bacterial Agents↗
PubMed1996

Genotypic characterization of a nosocomial outbreak of VanA Enterococcus faecalis.

Despite growing concern about vancomycin-resistant enterococci (VRE) as nosocomial pathogens, especially in the United States, in Italy VRE still represent an uncommon and occasional experience for most diagnostic laboratories. We report a genotypic characterization of the first reported nosocomial outbreak of VRE in Italy. Some experiments, including plasmid analysis and pulsed-field gel electrophoresis (PFGE) assays, aimed at investigating the genetic relatedness of the VRE isolates. Other experiments, based on hybridization and polymerase chain reaction (PCR) assays, aimed at characterizing the vancomycin resistance determinants. Over a 6-month period, 21 VRE, all identified as Enterococcus faecalis, were isolated from eight patients (all treated earlier with glycopeptide antibiotics) in a neurosurgical intensive care unit. All isolates had the same biochemical profile and antibiotic susceptibility pattern, including high-level resistance to aminoglycosides and vancomycin and teicoplanin MICs of 256 and 128 micrograms/ml, respectively. Three plasmids, one strongly hybridizing with a vanA probe, were detected in all but the last of the 21 VRE isolates. The last isolate of the cluster lacked the smallest of the three plasmids. Similar restriction profiles were obtained after plasmid DNA digestion with several endonucleases, with minor differences appreciated only in the first and last isolates. Analysis of genomic DNA restriction fragment patterns by PFGE confirmed that the reported cluster of VRE isolations was due to a single nosocomial strain of E. faecalis, despite some modifications in plasmid DNA at the beginning and at the end of the outbreak. Completely different PFGE patterns were yielded by vancomycin-susceptible E. faecalis strains isolated during the same period from inpatients in the same intensive care unit. Hybridization experiments with vanA and vanS-vanH probes and DNA amplification assays using 14 PCR primer pairs specific for vanA cluster genes (vanR, vanS, vanH, vanA, and vanY), orf1, orf2, vanB, and vanC showed identical organization of resistance determinants in all epidemic VRE isolates. This organization appeared to be the same as that described for Tn1546 in VanA prototype strain E. faecium BM4147.

Anti-Bacterial Agents↗
PubMed1995

Use of primers selective for vancomycin resistance genes to determine van genotype in enterococci and to study gene organization in VanA isolates.

Vancomycin resistance in enterococci is an emerging therapeutic problem. Resistance is not always detected by standard microbiological methods. Oligonucleotide primers for PCR were designed to target amplification of defined regions of genes of the vanA cluster, as well as vanB and vanC1. These primers correctly identified 30 vancomycin-resistant isolates tested (17 VanA, 7 VanB, and 6 Enterococcus gallinarum). No amplification was observed with Enterococcus casseliflavus or vancomycin-susceptible strains. Using PCR and Southern blotting, we found that all 17 VanA isolates had orf-1, orf-2, vanR, vanS, vanH, vanA, and vanY genes in the same sequence and that the intergenic distances in the vanR-vanA segments were the same. The described methods should be applicable to the rapid detection of the different vancomycin resistance genotypes in enterococci.

Anti-Bacterial Agents↗
PubMed1994

Differential susceptibilities of enterococcal species to elfamycin antibiotics.

The elfamycins are a class of naturally occurring antibiotics not currently used in the therapy of human disease. Enterococcus faecium and closely related species (Enterococcus durans and Enterococcus hirae) are susceptible to these antibiotics, while isolates of Enterococcus faecalis and other enterococcal species are highly resistant. Among enterococci, susceptibility or resistance to elfamycins appears to be determined by the bacterial protein synthesis elongation factor EF-Tu. Elfamycin susceptibility may be a useful adjunct for rapidly distinguishing E. faecalis and E. faecium in the clinical microbiology laboratory and/or as a supplementary test for use in determining the species of enterococci.

Anti-Bacterial Agents↗
PubMed1993

Antiphospholipid antibodies syndrome and cerebral ischemia.

Antiphospholipid antibodies are acquired circulating immunoglobulins that interact with phospholipids. These factors may manifest anticoagulant properties in vitro, interfering with phospholipid-dependent coagulation tests. They are not, however, associated with a hemorrhagic diathesis. Indeed, far from exerting the anticoagulant properties they possess in vitro, they are associated with episodes of thromboembolism, systemic and cerebral. We report the clinical and instrumental findings in 7 patients with ischemic stroke and circulating antiphospholipid antibodies classifiable as antiphospholipid antibodies syndrome.

Adult↗
PubMed1984

Accidental carbon monoxide poisoning.

In this case report of an accidental automobile carbon monoxide poisoning, we identify the following risk factors: freezing temperature, young passenger age, location in the rear of the auto, smaller patient mass, and auto disrepair. The pathogenesis of carbon monoxide poisoning is reviewed. Emergency treatment and suggested criteria for hyperbaric oxygen use in pediatric patients are discussed.

Accident Prevention↗