Effective catalytic disproportionation of aqueous H2O2 with di- and mono-nuclear manganese(II) complexes containing pyridine alcohol ligands.

The two novel manganese(II) complexes with 2-hydroxymethylpyridine (2-CH2OHpy) {[Mn2(µ-Cl)2(2-CH2OHpy)4]Cl2·2H2O (1)} and 2-hydroxyethylpyridine (2-(CH2)2OHpy) {[Mn(2-(CH2)2OHpy)2(NCS)2] (2)} were synthesized and characterized by means of X-ray diffraction, IR, EPR, HF EPR spectroscopy, magnetic and TG/DTG data. The complexes show catalase-like activity in neutral aqueous solution since they were able to disproportionate H2O2 to harmless H2O and O2. Both complexes act as true catalysts since they reverted to their original form after depleting all the H2O2, as suggested by the operando resonant inelastic X-ray spectroscopy (RIXS) measurements.

Complete nucleotide sequence of the pCTX-M3 plasmid and its involvement in spread of the extended-spectrum beta-lactamase gene blaCTX-M-3.

Here we report the nucleotide sequence of pCTX-M3, a highly conjugative plasmid that is responsible for the extensive spread of the gene coding for the CTX-M-3 extended-spectrum beta-lactamase in clinical populations of the family Enterobacteriaceae in Poland. The plasmid belongs to the IncL/M incompatibility group, is 89,468 bp in size, and carries 103 putative genes. Besides bla(CTX-M-3), it also bears the bla(TEM-1), aacC2, and armA genes, as well as integronic aadA2, dfrA12, and sul1, which altogether confer resistance to the majority of beta-lactams and aminoglycosides and to trimethoprim-sulfamethoxazole. The conjugal transfer genes are organized in two blocks, tra and trb, separated by a spacer sequence where almost all antibiotic resistance genes and multiple mobile genetic elements are located. Only bla(CTX-M-3), accompanied by an ISEcp1 element, is placed separately, in a DNA fragment previously identified as a fragment of the Kluyvera ascorbata chromosome. On the basis of sequence analysis, we speculate that pCTX-M3 might have arisen from plasmid pEL60 from plant pathogen Erwinia amylovora by acquiring mobile elements with resistance genes. This suggests that plasmids of environmental bacterial strains could be the source of those plasmids now observed in bacteria pathogenic for humans.

Mosaic structure of p1658/97, a 125-kilobase plasmid harboring an active amplicon with the extended-spectrum beta-lactamase gene blaSHV-5.

Escherichia coli isolates recovered from patients during a clonal outbreak in a Warsaw, Poland, hospital in 1997 produced different levels of an extended-spectrum beta-lactamase (ESBL) of the SHV type. The beta-lactamase hyperproduction correlated with the multiplication of ESBL gene copies within a plasmid. Here, we present the complete nucleotide sequence of plasmid p1658/97 carried by the isolates recovered during the outbreak. The plasmid is 125,491 bp and shows a mosaic structure in which all modules constituting the plasmid core are homologous to those found in plasmids F and R100 and are separated by segments of homology to other known regions (plasmid R64, Providencia rettgeri genomic island R391, Vibrio cholerae STX transposon, Klebsiella pneumoniae or E. coli chromosomes). Plasmid p1658/97 bears two replication systems, IncFII and IncFIB; we demonstrated that both are active in E. coli. The presence of an active partition system (sopABC locus) and two postsegregational killing systems (pemIK and hok/sok) indicates that the plasmid should be stably maintained in E. coli populations. The conjugative transfer is ensured by the operons of the tra and trb genes. We also demonstrate that the plasmidic segment undergoing amplification contains the blaSHV-5 gene and is homologous to a 7.9-kb fragment of the K. pneumoniae chromosome. The amplicon displays the structure of a composite transposon of type I.

Is retrieval of bone material from multiorgan donors effective enough to cover demand for biostatic bone tissue grafts in Poland?

In Poland there is growing demand for biostatic allogeneic bone transplantation mostly for traumatologic operations and orthopedic reconstructions. The bone material is primarily harvested during postmortem examinations in forensic and pathology laboratories. Nevertheless, the collected amounts are not sufficient, so that material needs to be acquired from alternative sources, such as multiorgan donors. Between 1998 and 2003, 2331 potential donors were registered by the Transplantation Coordinating Center in Warsaw, which was adjusted to 1794 donors who would have been accepted as donors of the bone tissue. Unfortunately, due to denials from family members and public prosecutors, the sample was only 1416 donors, which would cover about 40% of the clinical orthopedic demand in Poland.

Factors determining the contamination of bone tissue procured from cadaveric and multiorgan donors.

There is an increasing demand for bone allografts that are widely used in orthopedic reconstructive procedures. The bone tissue may be harvested from two sources: cadavers and multiorgan donors. Providing safe and valuable bone allografts is of paramount importance. Contamination of allografts during bone retrieval seems to be one of the most important problems since pathogenic microorganisms might be responsible for postoperative infections and complications in the healing process. The purpose of our study was to identify all factors contributing to bacteriological contamination of harvested bones. Therefore, we have considered factors such as harvesting environment, explantation techniques, storage and preparation of allografts, number of preceding procurements from the same donor, procurement duration, and time interval between death and tissue procurement. The microbiological evaluation of allografts has been performed by taking cultures from all collected bones. Our study revealed significantly greater contamination rates of bone allografts harvested from morgue than from multiorgan donors. According to this observation, we suggest that orthopedic surgeons should pay particular attention to obtain more bones of the highest quality, personally participating in multiorgan procurements.