Biomedical subjects

Amel Kechrid

Publications and source records attributed to Amel Kechrid.

7 recordsLinked to original sources

PubMed2004

DNA macroarray for identification and typing of Staphylococcus aureus isolates.

A DNA macroarray containing 465 intragenic amplicons was designed to identify Staphylococcus aureus at the species level and to type S. aureus isolates. The genes selected included those encoding (i) S. aureus-specific proteins, (ii) staphylococcal and enterococcal proteins mediating antibiotic resistance and factors involved in their expression, (iii) putative virulence proteins and factors controlling their expression, and (iv) proteins produced by mobile elements. The macroarray was hybridized with the cellular DNAs of 80 S. aureus clinical isolates that were previously typed by analyses of their antibiograms and SmaI patterns. The set selected contained unrelated, endemic, and outbreak-related isolates belonging to 45 SmaI genotypes. In a gene content dendrogram, the 80 isolates were distributed into 52 clusters. The outbreak-related isolates were linked in the same or a closely related cluster(s). Clustering based on gene content provided a better discrimination than SmaI pattern analysis for the tested mecA(+) isolates that were endemic to Europe. All of the antibiotic resistance genes detected could be correlated with their corresponding phenotypes, except for one isolate which carried a mecA gene without being resistant. The 16 isolates responsible for bone infections were distinguishable from the 12 isolates from uninfected nasal carriers by a significantly higher prevalence of the sdrD gene coding for a putative SD (serine-aspartate) adhesin (in 15 and 7 isolates, respectively). In conclusion, the macroarray designed for this study offers an attractive and rapid typing method which has the advantage of providing additional information concerning the gene content of the isolate of interest.

Bacterial Proteins↗

PubMed2004

[Pseudomonas aeruginosa: a multicentric study of antibiotic resistance (1999-2000)].

A retrospective multicentric study was carried out over a period of 2 years (1999-2000). 2659 strains of Pseudomonas aeruginosa were collected from 4 university hospitals (Charles Nicolle Hospital, Pediatric Hospital and National Centre of Bone Marrow Transplantation in Tunis, Habib Bourguiba Hospital in Sfax). Epidemiological profile and antibiotic susceptibility were analysed. All bacteria were identified by conventional methods and antibiotic susceptibility tests were performed according to CA-SFM guidelines. The strains were recovered essentially from surgical wards (33%) and intensive care units (22%). Pseudomonas aeruginosa was isolated mainly from pus (36%), urine (32%) and respiratory samples (18%). 25% of strains were resistant to ticarcilline, 18% to cefsulodine, 9% to ceftazidime, 14% to imipenem and amikacin and 25% to ciprofloxacin. Moreover, the resistance rates varied from hospital to hospital and from unit to another. The resistant strains were isolated particularly from urology and intensive care units: respectively 62% and 39% for ticarcilline; 26% and 13% for ceftazidime. The acquired resistance to b-lactams seems largely due to penicillinase production. The frequency of resistance to ceftazidime was the lowest and seems associated to chromosomal cephalosporinase over production.

Amikacin↗

PubMed2003

[Antibiotic sensitivity of Streptococcus pneumoniae in Tunisia: results of a multicenter study (1998-1999)].

We report the results of a multicenter tunisian study, performed over a two-year period (1998-1999), to determine the susceptibility pattern of Streptococcus pneumoniae in our country. A total of 146 S. pneumoniae were collected during the study period. 76 were recovered from adults and 70 from children. 53% of isolates have decreased susceptibility to penicillin, 24% with low level resistance, and 11% with high level resistance. Amoxicillin and cefotaxime decreased susceptibility rates were: 12% (low level resistance exclusively). and 14% (10% with low level resistance and 4% with high level resistance) respectively. Strains isolated from children, showed higher resistance to b lactams than those isolated from adults. Resistance rates to other antibiotics were as follow: erythromycin 28%, choramphenicol 14%, cyclins 23%, thrimethoprim-sulfamethoxazole 28% and rifampin 1%. No vancomycin resistant strain was found. The acquire resistance rates of Streptococcus pneumoniae in Tunisia are worrying, essentially for penicillin and erythomycin. Amoxicillin and cefotaxime have conserved a good activity.

Adult↗

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↗

PubMed2002

[Epidemiology of osteomyelitis and arthritis in infants].

A retrospective study realised over 10 years in the orthopaedic unit of the children's hospital of Tunis allowed to collect 206 cases of osteomyelitis and arthritis in infant (3 months--3 years old). In 74.6% of the cases, infection involved the joint. There is a single focus of the infection in 92.6% of the cases, more often at the lower limbs. The pathogen has been isolated in 33% of the cases. Staphylococcus aureus (52 %) is the more frequent pathogen, especially in osteomyelitis. Enterobateria (16%), Streptococcus (17.7%) (Streptococcus pneumonia: 10.7%), and Hemophylus influenzea (5.3%) were often isolated in arthritis.

Arthritis, Infectious↗

PubMed2002

[Value of reagent strips in screening urinary infection in children].

The aim of this study is to specify the role of rapid tests in the screening of childhood urinary tract infection. During the period between july to december 1998, 572 urinary samples were collected from pediatric out-patient in Hôpital d'Enfants de Tunis and aged from 1 month to 15 years. Only 75 samples (12.5%) were culture positive. The predictive value of leucocytes or nitrites test was 97.2%. These results allowed the use of rapid test in the screening of urinary tract infection in children. However, if clinical symptoms are present, the culture of urine must be associated to the rapid test.

Bacteriological Techniques↗

PubMed2002

[Epidemiologic profile of Haemophilus influenzae infection in Tunisia].

Haemophilus influenzae, a commensal bacteria, is frequently incriminated in broncho--pulmonary surinfections and severe diseases as meningitis, pneumonia and septic arthritis, particularly in young children. A multicenter study was conducted to establish the epidemiological profile of Haemophilus influenzae diseases, to determine the rate of antibiotics resistance for guide therapeutic and preventive strategies. The identification was based on the requirements for X and V factors, and the serotype b determined by agglutination. The betalactamase production was done by nitrocefin test. Antimicrobial susceptibility testing was determined on Muller Hinton chocolate agar with isovitalex. During the two year period, (January 1998 December 1999), 192 isolates of H. Influenzae were collected, 61% were recovered from invasive infections (44 meningitis, 8 bacteremia, 2 arthritis). The serotype b was identified in 55.7% of cases, 67.3% were invasive strains. 24.5% of isolates were producing betalactamase particularly invasive serotype b strains. All isolates of H. influenzae were susceptible to cefotaxim and to ofloxacin. Resistance rates to other antibiotics were: erythromycin 56.2%, tetracyclin 10.3%, rifampin 12%, chloramphénicol 1%, cotrimoxazole 16.5%, 11.5% amikacin and 20% gentamicin. The incidence of meningitis remained frequent in our country, involving the introduction of the vaccination in official calendar. Nevertheless, the surveillance of H. influenzae invasives infections and the serotyping of isolates were necessary to evaluate the impact of the immunization.

Anti-Bacterial Agents↗