Prevalence and mechanisms of macrolide resistance among Staphylococcus epidermidis isolates from neutropenic patients in Tunisia

The prevalence of macrolide-lincosamide-streptogramin (MLS) resistance phenotypes was determined among erythromycin-resistant Staphylococcus epidermidis isolates collected at the Bone Marrow Transplant Centre, Tunisia during 2002. The erm(A), erm(B), erm(C), msrA, mefA and icaA genes were detected by PCR. The vga, vgb and vat genes were amplified from pristinamycin-resistant isolates. The icaA gene was detected in 76.5% of 34 isolates examined in detail. The erm(C) (53%) and erm(A) (32%) genes predominated because of clonal dissemination, followed by msrA (15%). Gene distribution was related to the methicillin resistance pattern. The vga gene was present in combination with erm(A) in three isolates.     

Cytotoxicity effects of amiodarone on cultured cells

Amiodarone is a potent anti-arrhythmic drug used for the treatment of cardiac arrhythmias. Although, the effects of amiodarone are well characterized on post-ischemic heart and cardiomyocytes, its toxicity on extra-cardiac tissues is still poorly understood. To this aim, we have monitored the cytotoxicity effects of this drug on three cultured cell lines including hepatocytes (HepG2), epithelial cells (EAhy 926) and renal cells (Vero). We have investigated the effects of amiodarone on (i) cell viabilities, (ii) heat shock protein expressions (Hsp 70) as a parameter of protective and adaptive response and (iii) oxidative damage.Our results clearly showed that amiodarone inhibits cell proliferation, induces an over-expression of Hsp 70 and generates significant amount of reactive oxygen species as measured by lipid peroxidation occurrence. However, toxicity of amiodarone was significantly higher in renal and epithelial cells than in hepatocytes. Vitamin E supplement restores the major part of cell mortalities induced by amiodarone showing that oxidative damage is the predominant toxic effect of the drug.Except its toxicity for the cardiac system, our findings demonstrated that amiodarone can target other tissues. Therefore, kidneys present a high sensibility to this drug which may limit its use with subjects suffering from renal disorders.     

Prevalence of Mycoplasma pneumoniae-associated respiratory tract infections in hospitalized children: results of a 4-year prospective study in Tunis

Specific microbiologic, molecular, and serologic assays are hardly available in Tunis to confirm a suspected infection of Mycoplasma pneumoniae (MP). These diagnosis methods were used for the first time in a Tunisian prospective study to estimate the prevalence of MP infection in children and to evaluate their usefulness for diagnosis. A total of 540 children hospitalized in Tunis for lower respiratory tract infections (LRTIs) between 2005 and 2009 and 580 clinical specimens were investigated for the presence of MP by culture and by end-point polymerase chain reaction (PCR) targeting the P1 and the 16S rRNA genes. Real-time PCR was also used for MP detection on 158 respiratory samples. A total of 525 serum samples were tested for detection of MP-specific IgM and IgG. The P1 adhesin type and the antibiotic susceptibility testing were determined for the 9 clinical strains isolated during the study period. MP was detected in 33 (5.7%) clinical samples. Specific MP seropositivity was confirmed in 54 serum samples (10.3%), among which 19 (3.6%) were indicative of acute MP infection. MP infection was confirmed in 39 (7.2%) patients: 24 positive by PCR and/or culture, 10 serologically positive only, and 5 confirmed positive by both methods. MP infections occurred throughout the year with a slight decrease in autumn. The 9 MP isolates were susceptible to erythromycin, tetracycline, and ciprofloxacin, and all belonged to type I. The prevalence of MP infection in children with LRTI was 7.2% between 2005 and 2009, in Tunisia. Combination of direct detection and serology was required to enhance the clinical sensitivity of MP detection in clinical specimens.     

Resistance to pyrethroid insecticides in Culex pipiens pipiens (Diptera: Culicidae) from Tunisia

Resistance toward 2 pyrethro?d insecticides (permethrin and deltamethrin), and an organochloric one (DDT) was analyzed in 18 samples of Culex pipiens pipiens common mosquitoes collected from different Tunisian areas between March 2002 and November 2005. Bioassays were performed over different larvae samples. The recorded mortalities, after 24h exposure to increased doses of insecticides, were compared to those obtained on a susceptible reference strain (S-LAB). All samples were resistant to permethrin. However, a large variation in the tolerance to this insecticide was observed between samples. Resistance ratio levels at LC50 (RR50) for the analyzed samples were ranged from 1.5 to 9092 folds. For deltamethrin, 14 among 17 studied samples were resistant. RR50, in the resistant samples, were ranged from 3 to 453 folds. Resistance to the two tested pyrethroids and DDT were correlated. The use of synergists showed that the cytochrome P450-dependent monooxygenases had a major contribution to the permethrin and deltamethrin resistance and that the esterases (and/or glutathione-S-transferases) had only a minor contribution. Results were discussed in relation to resistance mechanisms and mosquito's control.     

Cervical human papillomavirus infection in Tunisian women

Background: It is well established that certain types of human papillomavirus (HPV) are the sexually transmitted agents etiologically linked to cervical cancer. Sexual habits have been shown to be a major determining factor for HPV infection. A large study was carried out to investigate the prevalence and risk factors associated with cervical infection with HPV in Tunisian women. Materials and Methods: PCR and restriction enzyme digestion were used to characterize HPV cervical infection in 106 Tunisian married women and 51 legal prostitutes. Epidemiological data were collected and correlated with HPV molecular genotyping. Results: There was a higher relative frequency of HPV-DNA in prostitutes (39%) than in married women (14%) (p = 0.001). Molecular analyses of HPV types showed the most prevalent type in prostitutes to be HPV-16, a high-risk oncogenic type. In married women, the most prevalent type was HPV-6 which is associated with a low risk for cervical cancer. HPV-DNA detection was markedly increased in young adult women and in those having recent sexual experience. Conclusion: Cervical HPV infection in Tunisia is less frequent than in other African countries, but far from uncommon. The decrease of HPV prevalence in older women, regardless of their sexual behavior, may result from an efficient immune response acquired with age. Received: July 1, 2002 · Revision accepted: December 23, 2002 L. Chouchane (corresponding author)     

Implantable Systems for Stress Urinary Incontinence

Stress urinary incontinence (SUI), the involuntary urine leakage due to failure of the urethral closure mechanism, is a global health challenge with substantial human suffering and socioeconomic costs. Approximately 167 million male and female patients are predicted to suffer from SUI in 2018, worldwide. A wide range of surgical interventions are available for the treatment of SUI. Severe cases, however, usually require the implantation of artificial urinary sphincter devices. This review comparatively presents and analyzes the working principles, as well as the challenges, associated with the current implantable SUI systems in clinical use. These include slings, urethral bulking agents, artificial urinary sphincters, and adjustable continence devices. It further reports on recent research progress and state-of-the-art in the field of SUI implants, including an original approach proposed by the authors with a pressure feedback sensory mechanism. The new emerging field of artificial muscle devices, including electroactive polymers, provides a promising innovative solution for replacing the weakened urethral sphincter in SUI patients.