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A Marchese

Publications and source records attributed to A Marchese.

At least 37 records · Page 2Linked to original sources
PubMed2001

Prevalence of antimicrobial resistance in Streptococcus pneumoniae circulating in Italy: results of the Italian Epidemiological Observatory Survey (1997-1999).

The Italian Epidemiological Observatory (IEO), a surveillance program supported by the SmithKline Foundation, analyzed the susceptibility of 2,664 community-acquired respiratory Streptococcus pneumoniae derived from over 50 clinical microbiology laboratories during 1997-1999, against 21 antibiotics adopting a quantitative methodology. Throughout these years, total penicillin resistance varied from 14.3% to 10.2%. High-level resistance has remained stable, ranging from 3.8% to 4.1%, while a decrease in low-level resistance (from 10.3% to 6.1%) has been recorded. Lack of susceptibility to macrolides ranged from 29.1% in 1997 to 25.5% in 1999. Similar figures have also been observed with tetracycline and co-trimoxazole (rates of resistance around 30%). As expected, large geographical variations in resistance rates were found for all drugs. Amoxicillin and amoxicillin-clavulanate were 100% active on penicillin-intermediate isolates. Injectable third-generation cephalosporins and carbapenems were also capable of inhibiting a large proportion of these microorganisms. Rifampin was the most potent non-beta-lactam compound tested. In contrast to the situation prevailing elsewhere, in Italian children (aged 0-5 years) presenting with respiratory conditions, the total rate of penicillin resistance (3%) was lower than that shown by the adult population (10.9%). However, lack of susceptibility to macrolides, tetracycline, and cotrimoxazole (35%, 41%, 44%) was more incident in pediatric than in adult patients (25%, 26%, 28% respectively). Strains recovered from blood in 1999 (67) were much more susceptible to penicillin (98.5%) than respiratory pneumococci (89.8%), whereas macrolides, tetracycline, and cotrimoxazole were consistently less active (75%, 67%, 64%).

Anti-Bacterial Agents↗
PubMed2001

Antibiotic persistence: the role of spontaneous DNA repair response.

Persisters are a small proportion of a bacterial population that exists in a physiological state permitting survival despite the lethal activity of antibiotics. To explain this phenomenon, it has been suggested that persisters are bacteria repairing spontaneous errors of DNA synthesis. To verify this assumption, Escherichia coli AB1157 and its lexA3 derivative were exposed to a dose 6x MIC of various antibiotics representative of different molecular mechanisms of action (ampicillin, ceftriaxone, meropenem, amikacin, ciprofloxacin). Bacterial cell counts, after 24 hr of exposure to the antimicrobials, revealed a reduction of about 90% of viable organisms in the lexA3 strains in comparison to the lexA+. In several cases, the number of colony-forming units decreased below the limit of assay. This behavior was noted with all antibiotics used, alone or in combination (amikacin plus ceftriaxone and amikacin plus ciprofloxacin). The same experiments were repeated using E. coli AB1157 cultured in the presence of mitomycin C (0.25x MIC), and the number of survivors exceeded by about 90% the values found in the nonexposed control. In contrast, in the sulA background, mitomycin C reacted synergically with all the antibiotics tested causing a strong reduction of the survivors in comparison with the control. The addition of chloramphenicol (0.125x MIC), on the contrary, caused a reduction of the number of survivors of about 90%. These findings indicate that, when DNA repair is active (a mechanism known to block cell division), the number of survivors is greater than that observed with lexA3. Thus, in addition to other possible explanations, persisters might be a fraction of bacteria that during antibiotic treatment are not growing because they are repairing spontaneous errors of DNA synthesis.

Anti-Bacterial Agents↗
PubMed2001

Epidemiology of major respiratory pathogens.

A vast literature attests to the fact that Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis represent the prevailing bacterial pathogens of community-acquired lower respiratory tract infections. Their specific incidence as causative agents of the more common syndromes is known to vary even profoundly, depending on geographic area, and the same holds true for their rates of resistance to antimicrobial drugs. Europe does not escape the threat posed by the present pandemic spread of penicillin resistance in S. pneumoniae although, as expected, some countries like Spain and France are highly affected and others including Germany, Italy, The Netherlands and the Scandinavian region, are relatively spared. In several sites multiple resistance has been described in S. pneumoniae with the most affected drugs being penicillin, the macrolides, co-trimoxazole and tetracycline. In H. influenzae synthesis of beta-lactamases is the main resistance trait expressed. Lack of susceptibility to beta-lactams dictated by a different mechanism remains extremely rare. Large variations in the incidence of this character are apparent when considering European countries. France and Spain are again widely affected while Germany, The Netherlands and Italy display rates of beta-lactamase-positive H. influenzae of about 16%. M. catarrhalis must be considered generally resistant to non-protected aminopenicillins since over 90% of these organisms produce beta-lactamases.

Anti-Bacterial Agents↗
PubMed2001

Microbial epidemiology patterns of surgical infection pathogens.

Resistance, as assessed in vitro, has a number of serious consequences in clinical situations. Treatment failures are common when an inappropriate drug has been prescribed and this, in turn, may lead to hospitalization of patients who normally would have been treated on an outpatient basis, as well as to longer hospital stay for inpatients and to the use of alternative drugs, which may be more expensive and more toxic. These factors all contribute to increased health care costs, morbidity and mortality. Microbiological procedures may identify the causative pathogen and provide the appropriate susceptibility pattern to the physician, thus reducing the chances of therapeutic failures. However, for a number of reasons including cost--even in hospitals--not to mention general practice, infections are seldom diagnosed on an etiological basis. From what has been stated, the knowledge of bacterial epidemiology and resistance represents basic support for correct therapeutic decision-making.

Anti-Bacterial Agents↗
PubMed2001

Role of global surveillance in combating bacterial resistance.

In recent years, one of the more alarming aspects of clinical microbiology has been the dramatic increase in the incidence of antibacterial resistance among pathogens causing nosocomial as well as community-acquired infections. Numerous antibacterial agents have lost their in vitro activity as a result of selective pressure exerted by antibacterial usage. There is a general consensus on the fact that emergence and spread of resistance may be delayed by improving hygiene measures, reducing inappropriate use of antibacterials, and adopting successful empirical therapy based on sound epidemiological data. As a consequence, worldwide international studies of antibacterial resistance surveillance have been established. Surveys such as the Alexander Project and the SENTRY Programme supply high quality data to participating countries, stimulate collaboration and provide the educational information required for clinical decision-making that may result in improved cure rates.

Anti-Bacterial Agents↗
PubMed2001

[Epidemiology of methicillin-resistance among Staphylococci strains isolated in risk units and effects of the vancomycin on the expression of methicillin-resistance].

Four hundred Staphylococci strains, isolated from different in intensive care unit hospitalized patients, were analyzed. 53% of all strains were resistant to methicillin. Against methicillin-resistant S. aureus (MRSA), teicoplanin and vancomycin (100% of susceptibility), rifampin (76.3%) and co-trimoxazole (73%) emerged as the most potent drugs tested; the 15% of the strains were susceptible to ciprofloxacin, erythromycin, clindamycin and gentamicin. Only one MRSA strain (0.8%) resulted hetero-resistant to vancomycin. Among 100 strains exposed to serial concentration of vancomycin (0.25-32 mg/L for 30 days), 57 were selected with intermediate-level of resistance to the glycopeptides; the MRSA strains have shown to acquire resistance in vitro more easily than methicillin-susceptible. These results indicate that in the clones of Staphylococci circulating in our region, the evolution of glycopeptides-resistance is not a rapid process and the loss of effectiveness of these antibiotics cannot be predicted to short term. In particular, the restriction profile analysis of chromosomal DNA from MRSA strains, selected in vitro with intermediate -level of vancomycin resistance, demonstrated that at the moment in the hospital departments studied, the diffusion of a clone able to acquire resistance more easily than others is not present.

Anti-Bacterial Agents↗
PubMed2000

Cloning and characterization of additional members of the G protein-coupled receptor family.

A search of the expressed sequence tag (EST) database retrieved a human cDNA sequence which partially encoded a novel G protein-coupled receptor (GPCR) GPR26. A human genomic DNA fragment encoding a partial open reading frame (ORF) and a rat cDNA encoding the full length ORF of GPR26 were obtained by library screening. The rat GPR26 cDNA encoded a protein of 317 amino acids, most similar (albeit distantly related) to the serotonin 5-HT(5A) and gastrin releasing hormone BB2 receptors. GPR26 mRNA expression analysis revealed signals in the striatum, pons, cerebellum and cortex. HEK293 and Rh7777 cells transfected with GPR26 cDNA displayed high basal cAMP levels, slow growth rate of clonal populations and derangements of normal cell shape. We also used a sequence reported only in the patent literature encoding GPR57 (a.k.a. HNHCI32) to PCR amplify a DNA fragment which was used to screen a human genomic library. This resulted in the cloning of a genomic fragment containing a pseudogene, psiGPR57, with a 99.6% nucleotide identity to GPR57. Based on shared sequence identities, the receptor encoded by GPR57 was predicted to belong to a novel subfamily of GPCRs together with GPR58 (a.k.a. phBL5, reported only in the patent literature), putative neurotransmitter receptor (PNR) and a 5-HT(4) pseudogene. Analysis of this subfamily revealed greatest identities (approximately 56%) between the receptors encoded by GPR57 and GPR58, each with shared identities of approximately 40% with PNR. Furthermore, psiGPR57, GPR58, PNR and the 5-HT(4) pseudogene were mapped in a cluster localized to chromosome 6q22-24. PNR and GPR58 were expressed in COS cells, however no specific binding was observed for various serotonin receptor-specific ligands.

1-Methyl-3-isobutylxanthine↗
PubMed2000

Resistance patterns of lower respiratory tract pathogens in Europe.

Resistance to antimicrobial drugs in the major respiratory tract pathogens is known to vary profoundly depending on geographic location. In Europe high rates (>44%) of penicillin-resistance in pneumococci have been recorded in France and Spain, while countries like The Netherlands, the Czech Republic, Austria and Italy are only marginally affected. Similarly, the incidence of macrolide resistance differs widely among European nations with figures ranging from 45.9% (France) to 1.5% (The Netherlands). Significant percentages (>20%) of co-trimoxazole and doxycycline resistance have been found in France, Spain, Italy, Hungary, Poland and Belgium. The prevailing mechanism of resistance in Haemophilus influenzae is represented by beta-lactamase synthesis for which considerable variations (from 0 to 38.5%) have been evidenced. Ampicillin resistant beta-lactamase negative H. influenzae are very uncommon. Over 90% of Moraxella catarrhalis isolates are beta-lactamase producers without big differences among European countries.

Drug Resistance, Microbial↗
PubMed2000

[Emergence of drug-resistant gram-positive pathogenic bacteria].

Staphylococcus aureus is a common cause of soft tissue infection, e.g. impetigo, cellulitis, or wound infection, and causes osteomyelitis, arthritis, bacteremia with metastatic infection, and scalded skin and toxic shock syndromes. Coagulase-negative staphylococci have become increasingly important causes of nosocomial bacteremia associated with invasive monitoring, intravascular catheters and prosthetic heart valves or joints. Most staphylococci produce blactamase and are resistant to penicillin. An increasing proportion of S. aureus have intrinsic resistance to methicillin (MRSA) and present major problems in hospitals for the control of cross infection. The glycopeptides, teicoplanin and vancomycin, are the antibiotics of first choice for treatment of these infections. After the first report describing a Japanese clinical isolate of vancomycin-resistant S. aureus (VRSA), several papers have documented the emergence of these microorganisms. Since the development and spreading of this phenomenon which is perceived as a fearsome threat to the already difficult therapy of nosocomial infections due to the prevalence of heterogeneous vancomycin resistance, we found the incidence of MRSA exceeds 35% in our hospital. Out of 179 methicillin-resistant S. aureus isolated during 1997-1998, two strains (1.1%) gave subclones with vancomycin MICs of 8 mg/L. PFGE showed identical restriction patterns for both isolates, suggesting transfer of a single clone between two different patients.

Cross Infection↗
PubMed2000

Antibiotic susceptibility patterns and serotypes of antibiotic resistant and/or invasive Streptococcus pneumoniae strains circulating in Italy.

Antibiotic susceptibility patterns and serotypes of 397 Streptococcus pneumoniae recovered from 1994 to 1998 in Italy have been determined. This collection included 229 penicillin- and/or erythromycin-resistant strains and 168 isolates responsible for invasive infections. Among penicillin-resistant pneumococci, the most prevalent serotype was 23F, followed by 19F and 9V, while among erythromycin-resistant but penicillin-susceptible strains serotype 6B was predominant followed by 19A, 14, 19F, 15A, 15B, and 23F. The most common invasive serotypes were 6B, 19F, 23F, 3, 4, 14, 20, 15B, and 9N. The currently available 23-valent pneumococcal vaccine could cover 91% of noninvasive penicillin- and/or erythromycin-resistant strains, 84% of pneumococci isolated from sterile sites, and 83% of invasive antibiotic-resistant S. pneumoniae. Penicillin-resistant pneumococci also showed reduced susceptibility to other antimicrobial compounds. Against invasive pneumococci, amoxicillin, cefotaxime, ceftriaxone, imipenem, vancomycin, and rifampin were 100% effective. Penicillin, chloramphenicol, erythromycin, tetracycline, and co-trimoxazole resistance was 1.8%, 9.5%, 15.5%, 18.5%, and 21.4%, respectively.

Anti-Bacterial Agents↗
PubMed2000

Molecular typing of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis: comparison of results obtained in a multilaboratory effort using identical protocols and MRSA strains.

Pulsed-field gel electrophoresis (PFGE) has become the gold standard of molecular methods in epidemiological investigations. In spite of its high resolving power, use of the method has been hampered by inadequate laboratory-to-laboratory reproducibility. In the project described here we have addressed this problem by organizing a multilaboratory effort in which the same bacterial strains (subtype variants of the Iberian and Brazilian methicillin-resistant Staphylococcus aureus--MRSA--clones) were analyzed by twenty investigators in thirteen different laboratories according to an indentical protocol, which is reproduced here in detail. PFGE patterns obtained were analyzed at a central laboratory in order to identify specific technical problems that produced substandard macrorestriction patterns. The results including the specific technical problems and their most likely causes are described in this communication. Also listed are seven major epidemic clones of MRSA which have been characterized by molecular fingerprinting techniques and the prototypes of which have been deposited at the American Type Culture Collection, from where they will be available for interested investigators for the purpose of typing MRSA isolates. It is hoped that this communication will contribute to the improvement of the reproducibility and technical/aesthetic quality of PFGE analysis.

Bacterial Typing Techniques↗
PubMed2000

Comparative in vitro potency of gemifloxacin against European respiratory tract pathogens isolated in the Alexander Project.

European isolates collected in 1998 for the Alexander Project were tested for their susceptibility to ciprofloxacin, ofloxacin and a novel fluoroquinolone, gemifloxacin, which has a spectrum of activity including common and atypical respiratory pathogens. MIC90s of gemifloxacin for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were 0.03, 0.06 and 0.015 mg/L, respectively. On the basis of MIC90s, gemifloxacin was the most potent antimicrobial tested against S. pneumoniae and M. catarrhalis. Against H. influenzae, gemifloxacin was one tube dilution more potent than ofloxacin and one tube dilution less potent than ciprofloxacin. As resistance to currently available antimicrobial agents increases, gemifloxacin offers potential as a promising new agent for the treatment of respiratory tract infection.

Anti-Infective Agents↗
PubMed2000

The evolving threat of antibiotic resistance in Europe: new data from the Alexander Project.

The Alexander Project was established in 1992 to examine the antimicrobial susceptibility of community-acquired lower respiratory tract bacterial pathogens to a range of compounds. Since then it has expanded both geographically and in the number of antimicrobial agents tested. Within Europe, the most recent data have confirmed that the prevalence of penicillin resistance among isolates of Streptococcus pneumoniae is high in France and Spain, with both intermediate (MIC 0.12-1 mg/L) and resistant (MIC > or = 2 mg/L) phenotypes, and combined resistance rates of >50%. Macrolide resistance is increasing generally both among penicillin-resistant and penicillin-susceptible isolates of S. pneumoniae and its prevalence now exceeds that of penicillin resistance, overall (16.5% and 10.4%, respectively, in 1996; 21.9% and 14.1% in 1997; 16.5% and 11.6% in 1998). Beta-lactamase production was the principal mechanism of resistance observed among isolates of Haemophilus influenzae and Moraxella catarrhalis.

Anti-Bacterial Agents↗
PubMed2000

Evolution of antibiotic resistance in gram-positive pathogens.

Staphylococcus aureus is a common cause of soft tissue infection, e.g. impetigo, cellulitis, or wound infection, and causes osteomyelitis, arthritis, bacteremia with metastatic infection, and scalded skin and toxic shock syndromes. Coagulase-negative staphylococci have become increasingly important causes of nosocomial bacteremia associated with invasive monitoring, intravascular catheters and prosthetic heart valves or joints. Most staphylococci produce b-lactamase and are resistant to penicillin. An increasing proportion of S. aureus have intrinsic resistance to methicillin (MRSA) and present major problems in hospitals for the control of cross infection. The glycopeptides, teicoplanin and vancomycin, are the antibiotics of first choice for treatment of these infections. After the first report describing a Japanese clinical isolate of vancomycin-resistant S. aureus (VRSA), several papers have documented the emergence of these microorganisms. Since the development and spreading of this phenomenon which is perceived as a fearsome threat to the already difficult therapy of nosocomial infections due to the prevalence of heterogeneous vancomycin resistance, we found the incidence of MRSA exceeds 35% in our hospital. Out of 179 methicillin-resistant S. aureus isolated during 1997-1998, two strains (1.1%) gave subclones with vancomycin MICs of 8 mg/L. PFGE showed identical restriction patterns for both isolates, suggesting transfer of a single clone between two different patients.

Anti-Bacterial Agents↗
PubMed2000

[Triple therapy of short-term with azithromycin, amoxycillin and omeprazole for the eradication of Helicobacter pylori].

BACKGROUND: The high cost and complexity of therapeutic schemes for the eradication of Helicobacter pylori has stimulated the search of simpler and cheaper treatment options. AIM: To evaluate the efficacy of 3 days of azithromycin 500 mg od, 7 days of amoxycillin 750 mg tid and omeprazole, 20 (Group A) or 40 mg (Group B) on randomization, as a treatment for Helicobacter pylori infection in patients with endoscopically diagnosed peptic ulcer. METHODS: H. pylori status of peptic ulcer patients was pathologically confirmed by the examination of five gastric biopsies using the Giemsa stain and by rapid urease testing in two gastric biopsies. H. pylori status was reassessed not less than 28 days after completing treatment. Adverse events and compliance were evaluated. RESULTS: Fifty four patients (29 men, 25 women, mean age 48 years) were enrolled, 28 in Group A and 27 in Group B. Per protocol the infection was cured in 58.8% of patients (30/51; 95% CI: 45-73%). On an intention to treat basis, H pylori infection was cured in 55%. Minor side effects including diarrhea and nausea were reported by 32% of patients. Ninety-five per cent of patients consumed more than 95% of prescribed medications. H. pylori was successfully eradicated in 61% of group A and 57% of group B patients (p = NS). CONCLUSION: Short term therapy with azithromycin was poorly effective in curing H. pylori infection. The compliance was excellent. Increasing Omeprazole from 20 to 40 mg/day did not improve treatment effectiveness.

Amoxicillin↗
PubMed1999

Trafficking of the HIV coreceptor CXCR4. Role of arrestins and identification of residues in the c-terminal tail that mediate receptor internalization.

The G protein-coupled chemokine receptor CXCR4 serves as the primary coreceptor for entry of T-cell tropic human immunodeficiency virus. CXCR4 undergoes tonic internalization as well as internalization in response to stimulation with phorbol esters and ligand (SDF-1alpha). We investigated the trafficking of this receptor, and we attempted to define the residues of CXCR4 that were critical for receptor internalization. In both COS-1 and HEK-293 cells transiently overexpressing CXCR4, SDF-1alpha and phorbol esters (PMA) promoted rapid internalization of cell surface receptors as assessed by both enzyme-linked immunosorbent assay and immunofluorescence analysis. Expression of GRK2 and/or arrestins promoted modest additional CXCR4 internalization in response to both PMA and SDF. Both PMA- and SDF-mediated CXCR4 internalization was inhibited by coexpression of dominant negative mutants of dynamin-1 and arrestin-3. Arrestin was also recruited to the plasma membrane and appeared to colocalize with internalized receptors in response to SDF but not PMA. We then evaluated the ability of CXCR4 receptors containing mutations of serines and threonines, as well as a dileucine motif, within the C-terminal tail to be internalized and phosphorylated in response to either PMA or SDF-1alpha. This analysis showed that multiple residues within the CXCR4 C-terminal tail appear to mediate both PMA- and SDF-1alpha-mediated receptor internalization. The ability of coexpressed GRK2 and arrestins to promote internalization of the CXCR4 mutants revealed distinct differences between respective mutants and suggested that the integrity of the dileucine motif (Ile-328 and Leu-329) and serines 324, 325, 338, and 339 are critical for receptor internalization.

Amino Acid Sequence↗