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Biomedical subjects

M Venditti

Publications and source records attributed to M Venditti.

At least 55 records · Page 3Linked to original sources
PubMed1998

In vitro susceptibility of Staphylococcus aureus isolated from blood to currently used antistaphylococcal drugs.

Changes in antibiotic susceptibility was evaluated in 77 consecutive nosocomial clinical isolates of Staphylococcus aureus collected from 1986 to 1994 at the Umberto I Polyclinic of the University of Rome (63 isolates) and from 7 other Roman hospitals (14 isolates). Oxacillin resistance in these isolates increased from 39% during the 1980s to 69% during the 1990s. Significant increases in resistance to ciprofloxacin, clindamycin and rifampicin were observed among oxacillin-resistant strains. No resistance to glycopeptides was observed although both teicoplanin and vancomycin had slightly reduced antistaphylococcal activity.

Anti-Bacterial Agents↗
PubMed1998

Fatal suppurative mesenteric thrombophlebitis caused by an Enterococcus faecalis highly resistant to aminoglycosides: case report.

A 56-year old man with non-Hodgkin's lymphoma and biliary tract endoprosthesis, developed chronic bacteremia caused by Enterococcus faecalis with high-level resistance to gentamicin and streptomycin. The sources of bacteremia were a device-associated biliary tract infection, a suppurative thrombophlebitis of the confluence of the superior mesenteric vein with the splenic vein as well as multiple liver and pancreatic abscesses. Despite antibiotic therapy and multiple drainages of abscesses, the patient died due to overwhelming infection.

Anti-Bacterial Agents↗
PubMed1998

[Streptococcus bovis endocarditis. Clinical and microbiological observations and review of the literature].

Fourteen patients (11 men and 3 women) with Streptococcus bovis infective endocarditis have been observed by the Infectious Disease Section of our Department of Clinical Medicine between the years 1988-1998. The mean age was 63.2 years (range 35-85 years); 5 patients previously suffered valvular disease or had a valvular prosthesis, the infection involved the mitral valve in 6 patients, the aortic in 8, the prosthetic valve in 1. No patient developed cardiac failure or died during hospitalization; only 1 episode of major embolism (spleen) was observed. No patient required cardiac surgery. All patients became afebrile after starting antibiotic treatment; no cases of Streptococcus bovis relapse have been observed, during a six-month follow-up after antibiotics discontinuation, in 13 patients fully evaluated. The remaining patient was lost to follow-up. An underlying asymptomatic colonic neoplasm was diagnosed at colonoscopy in 7 of 11 evaluated patients. This study confirms that Streptococcus bovis infective endocarditis is relatively benign, but it stresses the frequency and potential severity of the associated colonic lesions, requiring colonoscopy and making the treatment of high risk lesion mandatory.

Adult↗
PubMed1998

[Systemic Salmonella arizonae infections in patients with a deficiency of cell-mediated immunity. A report of 2 cases and a review of the literature].

Systemic infections induced by Salmonella arizonae have been described in patients with underlying cell-mediated immunodeficiencies, usually resident in southern countries of U.S. and in Mexico. This peculiar geographic distribution is probably due to the ingestion of meat or drugs from rattlesnakes, that Salmonella arizonae colonize in the intestinal tract and that live in the above areas. In this article we describe two cases of systemic Salmonella arizonae infections, that represent, to our knowledge, the first report in European literature.

Acute Disease↗
PubMed1997

Role of transthoracic and transesophageal echocardiography in predicting embolic events in patients with active infective endocarditis involving native cardiac valves.

Some studies describe an increased risk for emboli in infective endocarditis patients with large (>10 mm) and mobile vegetations. Other studies fail to demonstrate the above relation. Most studies have been performed using transthoracic echocardiography or with a monoplane transesophageal approach. The present study examines whether distinctive characteristics of vegetative lesions detected by transthoracic and multiplane transesophageal echocardiography are predictive of embolic risk. We reviewed both transthoracic and transesophageal echocardiograms of 57 patients with diagnosis of acute infective endocarditis and no documented or suspected previous embolic events. We evaluated site, length, width, mobility, and echodensity of vegetations. Twenty-five patients (44%) had embolic events. No statistical differences in age, sex distribution, location of endocarditis, or offending pathogens between embolic (n = 25) and nonembolic (n = 32) patients were found. There were no differences in any of the echo characteristics of vegetations detected by transthoracic and transesophageal approach in embolic and nonembolic groups. Thus, transthoracic and transesophageal characteristics of vegetations are not helpful in defining embolic risk in patients with infective endocarditis.

Adult↗
PubMed1997

Valvular perforation in left-sided infective endocarditis: a prospective echocardiographic evaluation and clinical outcome.

We undertook this study to determine the use of transthoracic and transesophageal echocardiography in detecting valvular perforation and the clinical impact of the latter on the outcome of left-sided infective endocarditis. Transthoracic echocardiography was performed in 58 consecutive patients with infective endocarditis. According to the study protocol, a subgroup of 42 patients also underwent transesophageal echocardiogrophy. At referral, 20 (34%) of 58 patients had echocardiographic evidence of valvular perforation (group A). No valvular perforations were found in the remaining 38 patients (group B). During a follow-up period of 27 +/- 16 months, a major complication occurred in 18 of 20 patients in group A and in 11 of 38 patients in group B (p < 0.0001). Univariate analysis indicated previous infective endocarditis, aortic involvement, and New York Heart Association functional class had a predictive value for valvular perforation (p < 0.001). Stepwise regression analysis confirmed aortic valve perforation as the only independent predictive variable for surgery and death. Valvular perforation is a common complication of infective endocarditis and is associated with an adverse outcome. Transthoracic echocardiography can detect or suggest valvular perforation in infective endocarditis, but transesophageal echocardiography better defines this complication and predicts severe heart failure or the need for early surgical management.

Adult↗
PubMed1997

Teicoplanin in the treatment of enterococcal endocarditis: clinical and microbiological study.

Seven cases of enterococcal endocarditis treated with teicoplanin (7-10 mg/kg/day for 28-105 days) alone (one case) or in combination with aminoglycosides (six cases) were reviewed. All patients were cured. Serum bactericidal activity titres after intravenous gentamicin (5 mg/kg every 24 h) and teicoplanin (10 mg/kg every 24 h) were measured on day 7 of treatment in four patients against five enterococcal isolates: mean titres were 1:54 (range 1:16-64) and 1:22 (1:8-32) at 0.5 and 24 h post-infusion, respectively. Time-kill studies showed synergy between teicoplanin and gentamicin against three isolates. We conclude that single daily-dose teicoplanin/gentamicin combined therapy may represent a rational alternative to standard penicillin/gentamicin therapy and a useful regimen for home treatment of selected cases of enterococcal endocarditis.

Adolescent↗
PubMed1997

The importance of in-vitro susceptibility testing in the management of compromised hosts.

Bacterial infection may be a life-threatening complication in the immunocompromised host, especially in the face of profound and persistent granulocytopenia induced by cytotoxicity. Under these circumstances, antibiotic therapy is started on an empirical basis; however, knowledge of the antibiotic susceptibilities of the offending pathogen may represent a useful guide for therapy adjustments in individuals who do not respond satisfactorily to initial antibiotics. Careful antimicrobial susceptibility testing may also represent the first step of epidemiology investigations of nosocomial outbreaks; moreover, knowledge of antibiotic susceptibility patterns of the prevalent pathogens in certain institutions may help clinicians to formulate empiric antimicrobial treatments for febrile granulocytopenic patients. Careful quantitative studies involving determinations of the minimal inhibitory concentrations may help to evidence early, potentially clinically significant decreases in susceptibility to first choice antibiotics for important nosocomial pathogens. Relationship between appropriate or inappropriate treatment, based on in-vitro susceptibility testing results, and clinical outcome may help to define the clinical significance of some emerging bacterial pathogens in immunocompromised patients.

Agranulocytosis↗
PubMed1996

Cure of mice with established metastatic friend leukemia cell tumors by a combined therapy with tumor cells expressing both interferon-alpha 1 and herpes simplex thymidine kinase followed by ganciclovir.

Transduction of the murine interferon-alpha (IFN-alpha) gene into various malignant mouse tumor cells has resulted in the loss of tumorigenicity and an acquired capacity to induce long-lasting antitumor immunity following their injection into immunocompetent syngeneic mice. In the present study, we investigated the effectiveness of IFN-alpha-producing tumor cells in the therapy of mice with established mouse tumors. In DBA/2 mice bearing subcutaneous (s.c.) Friend erythroleukemia cell (FLC) tumors, we found that to achieve some antitumor response (i) it was necessary to inject high numbers of IFN-alpha-producing FLC, which occasionally lead to the formation of slowly growing tumors; and, that (ii) repeated injections of irradiated IFN-alpha-FLC did not result in any antitumor effect. The therapeutic potential of IFN-alpha-producing FLC rendered sensitive to ganciclovir (GCV), by transfer of the herpes simplex virus thymidine kinase (tk) gene, was investigated. Complete tumor rejection and cure was observed in > or = 70% of the animals after injection of high numbers (10(7)) of IFN-alpha-producing tk-expressing tumor cells followed 4 days later by repeated GCV treatments, whereas only a slight increase in survival time was obtained after administration of control tk-expressing tumor cells (not producing IFN) and GCV. Tumor rejection was associated with a dramatic destruction of tumor tissue and with the subsequent development of a potent and long-lasting antitumor immunity. No therapeutic effect was observed in immunosuppressed nude mice. These data indicate that this approach may represent an effective and safe therapeutic strategy for antitumor cytokine gene therapy.

Animals↗
PubMed1996

Vancomycin susceptibility in enterococcal blood isolates in Italy: a multicenter retrospective analysis.

A retrospective, multicenter survey was performed to evaluate the frequency of vancomycin resistance among enterococcal blood isolates in Italian hospitals during 1993. Twenty-four laboratories, representing 21 cities, provided data on 177,623 blood cultures. Of 15,500 positive cultures, 778 (5%) yielded an Enterococcus. Of 362 evaluable cases of enterococcal bacteremia, a vancomycin resistant Enterococcus (VRE) was found in only 6 (1.6%). Based on these results, VRE bacteremia did not appear to be a major problem in Italian hospitals in 1993.

Anti-Bacterial Agents↗
PubMed1995

Correlation between the sensitivity or resistance to IL-2 and the response to cyclophosphamide of 4 tumors transplantable in the same murine host.

We have studied the anti-tumor response to cyclophosphamide (CTX) in DBA/2 mice transplanted s.c. with 4 tumors exhibiting different responses to IL-2: ESb lymphoma and Friend leukemia cells (non-responsive or poorly responsive, respectively), p11-R-Eb and Eb lymphoma cells (both highly responsive to IL-2). CTX injections on days 7, 14 and 21 resulted in a significant anti-tumor response in mice transplanted s.c. with Friend leukemia cells or ESb cells, whereas no anti-tumor effect was observed in mice injected with Eb or p11-R-Eb cells. All 4 tumor cell lines were equally sensitive to the cytotoxic effects of mafosfamide, an in vitro active analogue of CTX. To define the host mechanisms responsible for the lack of an anti-tumor effect of CTX in mice transplanted with IL-2-responsive tumors, we studied several aspects of the spontaneous or IL-2-induced anti-tumor response in mice transplanted with p11-R-Eb cells. Injection of monoclonal antibodies (MAbs) to IFN-gamma completely abolished the anti-tumor effects of IL-2. Using a Winn assay, clear-cut anti-tumor activity was found in spleen cells from mice transplanted with the IL-2-responsive tumors. This activity was abolished by CTX, which also abrogated the anti-tumor response to IL-2 in mice injected with p11-R-Eb cells. Our results indicate an inverse correlation between sensitivity to IL-2 and response to CTX and emphasize the importance of initial host-tumor interaction in determining the type of response to IL-2 or CTX.

Animals↗
PubMed1994

IFN-alpha 1 gene expression into a metastatic murine adenocarcinoma (TS/A) results in CD8+ T cell-mediated tumor rejection and development of antitumor immunity. Comparative studies with IFN-gamma-producing TS/A cells.

Cells from a spontaneous, invasive, and metastasizing mouse mammary adenocarcinoma (TS/A-pc) were transfected with a retroviral vector containing the mouse IFN-alpha 1 gene. TS/A clones secreting varying amounts of IFN-alpha 1 were isolated and their tumorigenicity was evaluated after s.c. or i.v. injection into immunocompetent BALB/c mice. Almost all of the IFN-alpha-secreting TS/A clones failed to grow in a high percentage of mice or formed small tumors after a long latency time, whereas TS/A-pc or transfection control cells always grew into large s.c. tumors. Rejection was mainly mediated by CD8+ T lymphocytes and partially by polymorphonuclear cells, as demonstrated by selective immunosuppression experiments and histologic and ultrastructural data. After rejection, a significant portion of mice displayed an immune resistance to the subsequent challenge with TS/A-pc. When the metastatic ability of IFN-alpha-secreting clones was compared with that of previously characterized IFN-gamma-secreting TS/A clones, it was found that the expression of IFN-alpha into TS/A tumor cells resulted in a potent inhibition of metastases formation, whereas IFN-gamma expression either did not affect or even enhanced the metastatic behavior of TS/A cells. These results provide strong evidence for the usefulness of IFN-alpha-producing tumor cells for the development of gene therapy strategies and vaccines against metastatic tumors.

Adenocarcinoma↗
PubMed1994

Increase in epsilon(gamma-glutamyl)lysine crosslinks in atherosclerotic aortas.

Portions of aortas from normal and atherosclerotic rabbits and from human autopsy subjects were washed and separated into layers which were subjected to exhaustive proteolytic digestion. The digests were assayed for epsilon(gamma-glutamyl)lysine crosslinks by a two-stage high performance liquid chromatography (HPLC) procedure. Crosslink concentrations in intima-media from rabbits where more than 15% of the aorta lumen surface was lesioned are greater than in normal aortas or aortas with less than 15% of the surface lesioned. Higher crosslink concentrations occur in fibrolipid plaques from human aortas than in intima-media layers of equal thickness from non-lesioned areas of the same aortas. Much of the crosslink in fibrolipid plaques occurs in the proteins which float at d < 1.18 g/ml. Non-lesioned areas of intima-media from aortas with fatty streaks or plaques have higher crosslink concentrations than intima-media from aortas with no lesions. In normal and lesioned intimas thinner than 0.2 mm, the concentration of the crosslink is lower than in the subjacent media. These findings indicate that increased epsilon(gamma-glutamyl)lysine crosslinking occurs in the atherosclerotic aorta and is associated principally with smooth muscle cells. It is suggested that the crosslinked products may be involved in retention of lipoproteins and the increase in collagen production.

Animals↗
PubMed1994

High rate of oxacillin-resistant Staphylococcus aureus isolates in an Italian University Hospital.

We reviewed our routine clinical laboratory records from January 1990 to March 1993 to evaluate the rate of oxacillin-resistance among nosocomial isolates of Staphylococcus aureus. Of 265 clinically significant isolates, 174 (65%) were oxacillin-resistant S. aureus (ORSA). Most of these strains were obtained from surgery patients and/or were isolated from surgical wounds. The isolations of S. aureus increased during the study period: 45 in 1990, 50 in 1991, 130 in 1992 and 40 in the first trimester of 1993. The annual rates of ORSA among S. aureus isolated varied from 62 to 68% through these years. Most ORSA isolates proved resistant to ciprofloxacin, gentamicin and rifampicin, and susceptible to vancomycin, netilmicin and cotrimoxazole. Based on these results, the need for a stringent application of infection control measures is outlined.

Cross Infection↗
PubMed1994

Infections by ampicillin-resistant enterococci: a case-control study.

We identified 17 (20%) of 83 consecutive enterococcal isolates from hospitalized patients with documented infection as high-level ampicillin-resistant enterococci (ARE). Of these, 16 isolates were identified as Enterococcus faecium and 1 isolate as Enterococcus raffinosus. A case-control study found no significant differences with respect to underlying diseases, central venous catheterization, nosocomial acquisition of the infection and sites of infection. Patients with ARE infection were older and had a higher inhospital fatality rate than those with ampicillin-susceptible Enterococcus (ASE) infection. Hospitalization in a surgery service (usually for an abdominal procedure), prolonged hospital stay, prior treatment with antibiotics (in particular imipenem and metronidazole), were also more frequent among patients with ARE infection. ARE isolates were more frequently resistant to imipenem, ciprofloxacin and streptomycin than ASE isolates.

Adult↗