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Biomedical subjects

M Scavizzi

Publications and source records attributed to M Scavizzi.

16 recordsLinked to original sources
PubMed1997

Oxacillin-hydrolyzing beta-lactamase involved in resistance to imipenem in Acinetobacter baumannii.

Acinetobacter baumannii strain A148, a clinical isolate resistant to imipenem (MIC = 32 mg l-1), synthesized two beta-lactamases with pIs 6.3 and > 9.2. The pI 6.3 enzyme hydrolyzed the penicillins, including isoxazoylpenicillins, first-, second- and, to a lesser extent, third-generation cephalosporins. It was inhibited by chloride ions and by the penem beta-lactamase inhibitor BRL 42715. Clavulanate was a weak inhibitor and EDTA did not affect the beta-lactamase activity. This enzyme also hydrolyzed imipenem with a catalytic efficiency (Kcat/Km) of 1500 mM-1 s-1. Moreover, this purified beta-lactamase produced a positive microbiological clover-leaf test with imipenem. Therefore, the pI 6.3 beta-lactamase was considered to be involved in the imipenem resistance of A. baumannii strain A148.

Acinetobacter↗
PubMed1993

[Infectious complications during treatments with interleukin-2].

Between January 1989 and May 1991, 97 patients were treated with interleukin 2 in the Oncology Department of the Avicenne Hospital (Bobigny, France). IL 2 was given over 5 days by continuous infusion through an implantable port. Ten patients (4 males, 6 females), mean age 46 years (36-67) with various cancers (breast 3, kidney 1, melanoma 1, colorectal 5), developed infection: 4 local infections around the port, 1 phlebitis, 4 septicemias, 1 bacteremia were observed. In 9 cases blood cultures were positive: Staphylococcus aureus 5, Staphylococcus epidermidis 3, Streptococcus G 1. In 5 cases the same pathogen was isolated from the port and from the blood. The mean leucocyte count was 10,627/mm3 at the time of infection. The delay between the beginning of interleukin 2 treatment and the infection was 3 months. The mean dose of IL 2 administered before infection was 456 million IU. In all cases infection was controlled without lethal complication by antibiotics and catheter removal. This high incidence (8 percent) of staphylococcal infection is partly due to the skin toxicity of IL 2 and to depressed neutrophil chemotactic response. Prophylactic antibiotics are warranted during IL 2 intravenous therapy.

Adult↗
PubMed1991

Pathogenesis of liver cirrhosis in alcoholic patients: histological evidence for hepatitis C virus responsibility.

Hepatitis C virus (HCV) has been proposed to be a cofactor in the pathogenesis of cirrhosis in patients with chronic alcoholism. The demonstration of a different liver histological pattern in anti-HCV positive patients might provide additional evidence. We studied 164 patients with chronic alcoholism, and histologically proven cirrhosis. For all of them, serum samples were collected at the time of a liver biopsy and stored at -80 degrees C. Testing for anti-HCV antibodies was done using the Ortho Diagnostic Systems Anti-HCV ELISA test. Only reproducible results were considered positive. A semi-quantitative assessment of seven histological parameters was made independently on liver biopsy samples. In the study group, 29 patients (18%) had anti-HCV antibodies. When compared with anti-HCV negative patients, both groups had similar ALT and AST seric activities. Anti-HCV positive patients had a greater score of mononuclear cells infiltrate (0.71 +/- 0.57 vs 0.41 +/- 0.52; p less than 0.05) and a lesser score of alcoholic hepatitis (0.19 +/- 0.57 vs 0.74 +/- 0.74; p less than 0.005). The scores for steatosis, perisinusoidal and perinodular fibrosis, and hepatocellular necrosis were similar in the two groups. In anti-HCV positive patients, with a clearly positive recombinant immunobinding assay (RIBA, Chiron-Ortho Diagnostic Systems), a greater score for hepatic necrosis and a lesser one for fibrosis were demonstrated. Among the seven patients with active cirrhosis, six were anti-HCV positive. Therefore, HCV is likely to play a role in the pathogenesis of liver damage in a few patients with alcoholic cirrhosis, especially, those with active cirrhosis.

Adult↗
PubMed1987

[A statistical model for interpreting the antibiogram].

Up to now, to interpret antibiotic susceptibility tests, the common practice has been to use: first, breakpoints without any quantitative justification, secondly, concordance curves between the different measurement techniques; these are not well adapted to the heterogeneous character of bacterial populations. We hereby propose another method: it is based on a global data analysis for each bacterial species, each antibiotic family and each measurement technique. So, we have drawn up a new model for the interpretation, both global and data-processed; it is based on qualifying classes, which are obtained and interpreted by hierarchical ascendent classification, principal components analysis, and comparison with pharmacological data. It can be used by any biologist. What is more, justified breakpoints with a numerical risk and quality control are defined. There are also some additional uses: evaluation of the effect of new antibiotics, standardization of new measurement techniques, detection of the emergence of new bacterial resistance in patients, guidance for research into unknown resistance mechanisms and characters.

Computers↗
PubMed1980

[Bacterial counts in sputum. The value and interpretation in lower respiratory tract infections (author's transl)].

A convenient and effective microtechnic of bacteria numeration in sputum has been used and its results are presented, considering the accompanying clinical data. One has therefore been able to appreciate the signification of the number and prevalance of bacteria isolated in lower respiratory tract infections: 1) The concentration of 10(7) bacteria/ml is a useful critical value, but it does not mean either virulence or lower limit of pathogenicity. 2) The importance of the predominance of a bacterial strain is an essential parameter in quantitative analysis. 3) The interpretation of the bacteriological results can only be made after thoroughly examining the cytology, the clinical infection symptoms, the anamnestic data, and considering the possibility of an antibiotic therapy preceding the test.

Bacteria↗
PubMedDate not supplied

Hepatitis C virus in patients with polyarteritis nodosa. Prevalence in 38 patients.

In order to assess the prevalence of hepatitis C virus (HCV) in polyarteritis nodosa (PN), 38 patients with systemic necrotizing angiitis were retrospectively tested for the presence of anti-HCV antibodies (Ab). Twenty-one patients were hepatitis B virus (HBV) positive, comprising group A, and 17 were HBV negative, comprising group B. Two patients from group A had anti-HCV Ab (2/21: 9.5%). One was treated unsuccessfully with corticosteroids, then with vidarabine and plasma exchanges; HBe/anti-HBe seroconversion was not observed and anti-HCV Ab disappeared 8 months after the onset of PN. The second patient was successfully treated with corticosteroids, then vidarabine and plasma exchanges; he recovered from PN, HBV seroconversion occurred, and the anti HCV Ab remained detectable. These results show that: 1) the prevalence of anti HCV Ab in PN related to HBV is nearly the same (9.5%) as the prevalence of HCV Ab observed in patients with chronic hepatitis related to HBV infection; 2) the course of these two viral infections can be different and the role of HCV as an etiologic factor in PN has not been established.

Adult↗
PubMedDate not supplied

[Moraxella (Branhamella) catarrhalis. A common pathogenic agent].

Moraxella (Branhamella) catarrhalis, a commensal organism of the oropharyngeal flora, has been considered a potential pathogen since the early 1970s, mainly causing otitis in infants and exacerbations of chronic bronchitis in the elderly or in immunosuppressed adults. This view was initially based on the isolation of M. catarrhalis during infections: a density of at least 10(7)/ml of sputum, particularly when it exceeds that of other organisms by at least 100-fold, is considered to indicate the responsibility of M. catarrhalis. The pathogenic potential of M. catarrhalis was proven by the increase in specific serum antibodies (total, IgG, IgA) in patients infected by this organism. Given the large proportion (60 percent) of strains that produce beta-lactamase, antibiotic therapy is based on a combination of amoxycillin and clavulanic acid (or another penicillin/beta-lactamase inhibitor combination) or a third-generation cephalosporin; tetracyclines or macrolides can also be used.

Anti-Bacterial Agents↗