Biomedical subjects

Assia Ben Hassen

Publications and source records attributed to Assia Ben Hassen.

7 recordsLinked to original sources

PubMed2004

Phenotypic and molecular characterization of macrolide and streptogramin resistance in Streptococcus mitis from neutropenic patients.

OBJECTIVES: To determine the prevalence of macrolide and streptogramin resistance in Streptococcus mitis isolates from neutropenic patients and to identify mechanisms of macrolide and streptogramin resistance in resistant isolates. METHODS: MICs of erythromycin, spiramycin, lincomycin and pristinamycin were determined for S. mitis isolates. Macrolide-resistance genes were characterized by PCR and ribosomal mutations by sequencing. RESULTS: A total of 169 S. mitis isolates were recovered from 66 patients at the Tunisian Bone Marrow Transplant Centre. Of these, 120 (70%) were non-susceptible to erythromycin and one was resistant to pristinamycin; 48.5% of isolates had an MLSB phenotype with cross-resistance between erythromycin, spiramycin and lincomycin, 4% had a dissociated MLSB phenotype with resistance to erythromycin and spiramycin but apparent susceptibility to lincomycin and 47.5% displayed the M phenotype. Resistance determinants were characterized in 33 isolates. Ten of 14 isolates with the cross MLSB resistance contained an ermB-like gene and four a combination of ermB- and mefA-like genes. Four of the five isolates with a dissociated MLSB phenotype contained ermB-like and one a combination of ermB- and mefA-like genes. All the 14 isolates with an M phenotype contained mefA-like genes. The pristinamycin-resistant strain had G105 and A108 substitutions in the conserved C terminus of the L22 ribosomal protein. CONCLUSIONS: The prevalence of macrolide resistance is high in S. mitis from neutropenic patients and is due to the spread of ermB- or mefA-like genes alone or combined. Resistance to streptogramins is rare and in this case associated with ribosomal mutation.

Amino Acid Sequence↗

PubMed2004

rpoB mutations in Streptococcus mitis clinical isolates resistant to rifampin.

Activity of rifampin against 129 Streptococcus mitis isolates obtained from patients with hematologic cancer was investigated. One hundred twenty-five strains were susceptible to rifampin, and 4 were resistant (MIC = 32 to 64 microg/ml). Resistance to rifampin was related to mutations in the rpoB gene: His(526)Asn in three strains and His(526)Asp in one strain.

Antibiotics, Antitubercular↗

PubMed2004

Prevention of central venous line-related thrombosis by continuous infusion of low-dose unfractionated heparin, in patients with haemato-oncological disease. A randomized controlled trial.

We have conducted a prospective randomized controlled trial to evaluate the role of low-dose unfractionated heparin prophylaxis in preventing central venous line-related thrombosis in patients with haemato-oncological disease. Patients were randomly assigned to receive either prophylactic intravenous unfractionated heparin (continuous infusion of 100 IU/kg/daily) or 50 ml/daily of normal saline solution as a continuous infusion. CVLs were externalized, non tunneled, double lumen catheters. All CVLs were placed percutaneously by the same physician in the subclavian vein. Upper limb veins were systematically examined by ultrasonography just before, or <24 hours after, catheter removal, and in case of clinical signs of thrombosis. One hundred and twenty-eight CVLs were inserted. Catheter-related thrombosis occurred in 1.5% of the catheters inserted in patients of the heparin group, and in 12.6% in the control group (p = 0.03). No other risk factors were found for the development of catheter-related thrombosis. Two and three patients experienced severe bleeding in the heparin group, and in the control group, respectively (p = 0.18). There were no other side-effects clearly ascribable to the use of unfractionated heparin. This is the first prospective, randomized study, which shows that low-dose of unfractionated heparin is safe and effective to prevent catheter-related thrombosis in patients with haemato-oncological disease.

Adolescent↗

PubMed2003

[Enterococcus faecalis: a multicenter study on antibiotic resistance].

676 E. faecalis strains were listed over a period of 2 years from the Charles Nicolle hospital of Tunis (167 strains), the Habib Bourguiba hospital of Sfax (350 strains) and the National Centre of Bone marrow Transplantation of Tunis (159 strains). Antibiotic sensibility study was realized by the method of the antibiogram, E-test method and the search of penicillinase by cefinase. E. faecalis resulted essentially from services of onco-haematology (24%), external consultations (23%), surgery (18%) and medicine (15%). These strains were isolated especially from urines (54%), coprocultures (15%), bloodcultures (11%) and from pus (9%). Resistance acquired with these strains is raised for erythromycin, tetracyclin and chloramphenicol (81% to 86%), followed by high level resistance to gentamicine (37%). 0.1% of E. faecalis strains have a low level resistance to amoxicillin without production of penicillinase. No resistance to vancomycin was observed.

Amoxicillin↗

PubMed2003

[Antibiotic resistance among E. coli isolates from urinary tract infections (1999-2000): a multicenter study].

E. coli is the most frequently isolate species in community as well as in nosocomial acquired urinary tract infections (UTI). Trimethoprim-sulfamethoxazole (TMP-SMX), is commonly used as empiric treatment for managing uncomplicated UTI whereas the rate of resistance to amoxicilline is increasing. A multicentric retrospective study was conducted from January 1st 1999 to December 31st 2000 to evaluate the prevalence of E. coli isolates from UTI and to guide empiric therapies. Among 6994 urinary isolates, 62.6% were resistant to amoxicilline, this rate fell to 33.6% when amoxicilline was associated to clavulanic acide, 2.7% were producing extended spectrum b-lactamases (BLSE), higher than reported in France and USA. 37.3% were resistant to TMP-SMX. The high prevalence of antimicrobial resistance among UTI E. coli isolates emphasizes the necessity to review the empiric therapies. Fluoroquinolones can be considered as an alternative therapy according to their excellent tissue penetration and their wide spectrum of activity.

Anti-Bacterial Agents↗

PubMed2003

[Recurrent pregnancy loss related to immune disorders].

Progress in immunologic methods and diagnostic assays over the last two decades has led the description of an association between some cases of recurrent fetal loss and recurrent spontaneous abortion of unknown cause to immunological factors. Some causal immunological diseases or dysregulations have been identified in pregnant women. These abnormalities may precede or be triggered by the pregnancy, or occasionally result from an impairment of the mother's allogeneic response to the fetus. In this article we review the principal immunological factors and abnormalities implicated in recurrent pregnancy loss and focusing on those generally accepted by the majority of authors.

Abortion, Habitual↗

PubMed2002

[Multidrug resistance in Klebsiella pneumoniae: multicenter study].

The extensive use of broad spectrum antibiotics, especially the third generation cephalosporins (C3G), was followed by the emergence of newer plasmid mediated betalactamases called extended spectrum betalactamases (ESBLs). To assess the impact of K. pneumoniae resistant to 3GC in Tunisia, this study was conducted in 3 teaching hospitals. A total of 1110 strains of K pneumoniae was collected. The antibiotics susceptibilities were tested by diffusion method using Mueller-Hinton agar. The quality control was regularly performed. I ESBLs producing solates were detected using the double-disc synergy test. Data analysis was done using the Whonet 4 software. 23.6% K. pneumoniae isolates showed phenotype pattern of ESBLs producers. The double-disc synergy test was positive in 75% of the cases. These isolates were recovered from hospitalized patients in different wards but mainly from pediatrics (23.6%), medicine (23.2%), surgery (22.9%), intensive care units (11%) and neonatology (11%). 54% were isolated from urines, 22% from blood cultures. These isolates remained susceptible to imipenem (100%) and most of them to cefoxitin (96.4%) but all had associated resistance to aminoglycosides, quinolones and trimethoprim-sulfamethoxazole. The prevalence of multidrug resistant K. pneumoniae is high. This resistance can be minimized by the implementation of infection control measures including handwashing and isolation procedures.

Adolescent↗