Macrolide-resistance genes were investigated in 103 macrolide-resistant strains of Streptococcus pyogenes, isolated from children with pharyngotonsillitis. The presence of mef(A), erm(B), and erm(TR) ...genes was detected by PCR. mef(A) was found in 48 out of 103 (46.6%) strains, whereas erm(B) was detected in 43 isolates (41.7%). All mef(A) strains showed a typical M phenotype (resistance to 14- and 15-membered macrolides, and sensitivity to lincosamides and streptogramin B), whereas erm(B) strains had the MLSB phenotype (resistance to macrolides, lincosamides, and streptogramin B antibiotics). erm(TR) was found in 10 strains, always together with other resistance genes. In seven cases erm(TR) was associated with erm(B), and three cases with mef(A). In two isolates with the M phenotype (1.9%), it was not possible to detect the presence of any of the three macrolide resistance genes tested. Inducible resistance to macrolides was shown for 24 out of the 53 MLSB strains. Analysis of macrorestriction fragment patterns by pulsed-field gel electrophoresis showed that erythromycin-resistant S. pyogenes are polyclonal, however each phenotype, MLSB and M, formed essentially homogeneous groups.
Choline‐binding proteins (CBPs) from Streptococcus pneumoniae are involved in several important processes. Inactivation of zmpB, a gene that encodes a surface‐located putative zinc metalloprotease, ...in a S. pneumoniae serotype 4 strain was recently reported to reveal a composite phenotype, including extensive chain formation, lysis defect and transformation deficiency. This phenotype was associated with the lack of surface expression of several CBPs, including the major autolysin LytA. LytA, normally 36 kDa in size, was reported to form an SDS‐resistant 80 kDa complex with CinA. ZmpB was therefore proposed to control translocation of CBPs to the surface, possibly through the proteolytic release of CBPs (and RecA) from CinA. Based on the use of 12 independent mariner insertions in the zmpB gene of the well‐characterized R6 laboratory strain, we could not confirm several of these observations. Our zmpB mutants: (i) did not form chains; (ii) lysed normally in the presence of deoxycholate, which indicates the presence of a functional autolysin; (iii) transformed at normal frequency; and (iv) contained bona fide CinA and LytA species. Polymorphism of ZmpB between R6 and the serotype 4 isolate could not account for the discrepancy, as inactivation of zmpB (through replacement by transposon‐inactivated zmpB R6 alleles) in the latter strain did not affect separation of daughter cells and autolysis. The conflicting observations could be explained by our finding that the reportedly serotype 4 zmpB‘mutant’ differed from its S. pneumoniae parent in lacking capsule and in exhibiting characteristic traits of the Streptococcus viridans group, including resistance to optochin.
The objective of the research is aimed at understanding which is the effect on peoples habits of TCMs as pricing measures. In particular it is important to know how the people change their behaviour ...in function of the cost of accessibility to some defined areas. To catch this goal, an overview of the experiences carried out in the world concerning road pricing is presented and a deep analysis of them is given to understand their effectiveness in terms of reduction of traffic. Subsequently, a survey a medium-size Italian town was carried out, focused to understand the willingness of people to pay to enter into urban areas subjected to pricing. The results have emphasised that the people are sensible to the problems that traffic causes to the environment, but their sensibility is totally given up by their behaviour: 59% are not disposed to pay anything to use the roads. The most significant variables influencing the willingness to pay of the people are the home location the necessity and the number of times to go to the centre. Who lives in the very central zone is well-disposed to pay until 2 f (about 1.8 USD), The results of the survey seem to confirm the behaviour of the people that is experimenting the road pricing in some cities of the world.
Opsonization enhances Streptococcus pneumoniae-induced human monocyte-derived macrophage (MDM) apoptosis. Both depletion of complement and immunoglobulin from opsonizing serum and blockade of the ...macrophages CR1, CR3, FcgammaRII, and FcgammaRIII partially decreased MDM apoptosis after S. pneumoniae phagocytosis, and these effects correlated with reduced numbers of internalized bacteria. Chloramphenicol inhibition of protein synthesis by opsonized S. pneumoniae down-regulated subsequent MDM apoptosis. Phagocytosis of an unencapsulated mutant of S. pneumoniae resulted in increased MDM apoptosis, in association with enhanced internalization. Caspase inhibition was associated with decreased killing of bacteria. Enhanced induction of apoptosis by opsonized S. pneumoniae is the result of increased intracellular burden of bacteria, rather than of a specific pattern of engagement of complement receptor or FcgammaR. A dynamic interaction between live intracellular bacteria and the host cell is necessary for induction of apoptosis in MDMs, and induction of apoptosis contributes to the host defense against S. pneumoniae.
The analysis of the noise impact caused by traffic on the population is a part of a large research program regarding a methodology focused to define "standard sites" in which to make traffic and ...noise measurements and to study the impact on the population. A survey has been carried out in some urban roads of the city of Turin, where two main noise sources are present: vehicular traffic and trams. The objectives were to evaluate the perceived disturb by the population in function of some parameters of the monitored sites (i.e. noise, traffic, geometric conditions, surrounding environment, etc.). Some operating phases have been defined to carry out the pilot survey. So, the sites were selected in term of the noise sources and the sit
Direct sequencing of polymerase chain reaction (PCR)-generated templates is a commonly used technique in molecular biology laboratories. We describe an improved method for direct sequencing of PCR ...fragments longer than 20 kb obtained with a commercial mixture of Taq and Pwo DNA polymerases. The sequencing protocol was optimized for an automated infrared DNA sequencer, consistently yielding long reads (500-600 bases).
Cryptic plasmids pDP1 and pSMB1 from clinical strains of Streptococcus pneumoniae isolated 74 years apart were found to be essentially identical in their nucleotide sequence. pDP1, 3161 bp, contains ...five codirectional ORFs and presents all the general features of plasmids replicating by the rolling circle mechanism. The rep gene, 963 bp, is highly homologous to the rep gene of other streptococcal plasmids of the pC194 family.
A reliable selective PCR procedure that combines the use of additionally mutated primers with the specificity-enhancing properties of a commercial preparation (Perfect Match, Stratagene) is ...described. The human immunodeficiency virus type 1 pol gene point mutations known to confer in vitro resistance to azidothymidine were examined as a model for optimization of the assay. The usual strategy of deliberately introducing an additional mismatch 1 residue from the 3' end in the wild-type and mutant primers did not allow reproducible discrimination between wild-type and mutant target sequences. Addition of minimal amounts of Perfect Match to the same PCR mixtures resulted in a significantly enlarged range of selective annealing temperatures, providing a valuable and cost-effective means for reliable detection of known mutations by selective PCR.
Tumor Proliferative Fraction (TPF) has been shown to correlate with prognosis in some malignancies. A reliable, accurate method for application in a clinical practice is still being sought. The aim ...of this study is to compare TPF as determined by Proliferating Cell Nuclear Antigen (PCNA) and Flow Cytometry (FC) in 36 consecutive patients affected by Renal Cell Carcinoma (RCC). Proliferating cells were identified in paraffined sections using a anti-PCNA monoclonal antibody (PC 10 Dako). Cell suspension for FC were prepared from fresh/frozen samples DNA index and S phase were evaluated using a computerized program (Multicycle, Phoenix). 16 samples (47.1%) were found to be aneuploid by FC (DI range 0.72-2.40). Aneuploid vs diploid tumors had significantly higher mean FC-S phase (p = 0.049) and PCNA LI (p = 0.034). Weak correlation (r-Spearman 0.416 p = 0.01) was found between PCNA LI and grading and near to significativity between PCNA LI and tumor size (r = 0.335 p = 0.0061). When patients are classified according to nuclear grading, is evident that all PCNA G4 are aneuploid and that 62.5% of PCNA G1 are diploid. A week correlation near to significativity is found between PCNA LI and S phase only in the aneuploid tumors. A more reliable measurement of TPF in RCC could be provided by combining the two methods. Further research on larger series is needed.
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