High prevalence of multidrug-resistant international clones among macrolide-resistant Streptococcus pneumoniae isolates in immunocompromised patients in Tunisia.

OBJECTIVES: Macrolide-resistant Streptococcus pneumoniae isolates have increased considerably in the last decade, with important geographical variations in involved phenotypes and genotypes. The aim of this study was to investigate phenotypes, genotypes, serotypes and genetic relatedness of macrolide-resistant S. pneumoniae isolated from immunocompromised patients in Tunisia. METHODS: Antibiotic susceptibility was determined by disk diffusion, and MICs of erythromycin and clindamycin were determined for macrolide-resistant isolates by Etest. Macrolide-resistant isolates were analysed by PCR for ermB, mefA, tetM, tetO and Int-Tn1545. Serotyping was done by multiplex PCR and the Quellung reaction. Multilocus sequence typing (MLST) was performed for molecular typing. RESULTS: Macrolide resistance was observed in 41 (69.5%) of 59 isolates. Of the 41 isolates, 37 (90.2%) had a macrolide-lincosamide-streptogramin B (MLSB) resistance phenotype, with a predominance of high-level inducible MLSB phenotype, and harboured the ermB gene. All isolates with high-level inducible MLSB phenotype were highly resistant to erythromycin and clindamycin. Four isolates (9.8%) had a macrolide (M) resistance phenotype and harboured the mefA gene. Erythromycin-resistant isolates were multidrug-resistant (MDR) in 97.5% of cases and extensively drug-resistant in 12.2%. The isolates belonged essentially to four serotypes (19F, 23F, 14 and 6B). They were mainly assigned to three sequence types (ST81, ST2918 and ST386). Also, 65.9% of the isolates were grouped in three clonal complexes (CC81, CC838 and CC386). CONCLUSIONS: These data indicate a high prevalence of Tn1545 transposon and of three MDR international clones contributing to the high frequency of multidrug resistance among S. pneumoniae isolates in our centre.

Description of a novel mutation in the atpC gene in optochin-resistant Streptococcus pneumoniae strains isolates from Tunisia.

Identification of Streptococcus pneumoniae among other α-haemolytic streptococci is based on phenotypic or genotypic characteristics such as colony morphology, bile solubility and optochin susceptibility. This study reports three optochin-resistant S. pneumoniae strains isolated from immunocompromised patients in Tunisia. The three isolates were positive for the bile solubility test. Biochemical identification with API® 20 Strep was not discriminatory for two strains. The three strains had different serotypes (6C, 19F and 23F) and three different sequence types (ST386, ST320 and ST326). Sequencing of the atpA and atpC genes for each strain showed only modification in atpC. The mutations Met13→Val or Val48→Ile were observed in two strains. However, in the third strain a novel type of mutation (Val15→Ile) was identified.

Distribution of virulence associated traits among urine Escherichia coli isolates from patients in onco-hematology.

Escherchia coli is the most common etiological agent of urinary tract infections. In this study we had two goals: First of all, to find out if urine stains isolated from our patients--having the particularity of being immunocompromised--would have a virulence genes distribution different from the one observed in strains isolated from ordinary patients. Second, we wanted to identify a common virulence profile associated to these particular strains. The prevalence of virulence factors (VF)-encoding genes was analyzed by PCR. Of the tested VF-encoding genes, malX (80%), ompT (79%), fyuA (74%), usp (67%), chuA (66%), iroN (59%), iutA (56%), papC (36%), pap AH (30%), papEF (28%), hlyA (28%), papG allele II (25%), cnf1 (21%), focG (20%),cvaC (20%) and papG allele III (7%) were significantly associated to urinary strains. Virulence genes distribution of urinary strains isolated from onco-hematology patients and the one observed in strains isolated from ordinary patients are almost the same. The virulence profiles containing adhesins type 1, S and F1C fimbriae, siderophore genes and three individual genes ompT, usp and malX were present in half of the urinary strains and were significantly associated to them. Two virulence signatures occurred significantly in UTI-causing strains (12%). These findings provide first insight into the virulence of UTI-causing E. coli strains isolated in onco-hematology patients.

Serotype Distribution, Antibiotic Resistance and Clonality of Streptococcus pneumoniae Isolated from Immunocompromised Patients in Tunisia.

BACKGROUND: Pneumococcal disease, a major cause of morbidity and mortality globally, has higher incidence among young children, the elderly and the immunocompromised of all ages. In Tunisia, pneumococcal conjugate vaccines (PCVs) are not included in the national immunization program. Also, few studies have described the epidemiology of S. pneumoniae in this country and, in particular, no molecular typing studies have been performed. The aim of this study was to evaluate serotype distribution, antimicrobial resistance and clonality of Streptococcus pneumoniae isolated from neutropenic patients in Tunisia. METHODS: Fifty-nine S. pneumoniae were isolated from infection (n = 31) and colonization (n = 28) sites of patients (children and adults) attending the National Centre of Bone Marrow Transplantation in Tunis between 2005-2011. All isolates were characterized by serotype, antimicrobial resistance pattern and multilocus sequence typing (MLST). RESULTS: The majority (66.1%) of the isolates belonged to five serotypes all included in PCVs: 6B, 9V, 14, 19F and 23F. The potential coverage of the 10-valent and 13-valent PCV was of 71.2% and 76.3% respectively. Resistance rates were very high and 69.5% of the isolates were multidrug resistant: non-susceptibility rates to penicillin, amoxicillin and cefotaxime were 66.1%, 40.7% and 27.1%, respectively; resistance rates to erythromycin, clindamycin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole, were 69.5%, 61.0%, 37.3%, 22.0% and 67.8%, respectively. The most frequent serotypes had STs characteristic of multidrug resistant international clones known to be highly successful and important causes of pneumococcal infection: Spain 23F-ST81, France 9V/14-ST156, Spain 6B-ST90, 19F-ST320, and Portugal 19F-ST177. CONCLUSIONS: The majority of S. pneumoniae strains recovered from immunocompromised patients in Tunisia are representatives of multidrug resistant pandemic clones that express serotypes targeted by PCVs. To contain the burden of pneumococcal disease and improve treatment choices among Tunisian immunocompromised patients PCVs should be offered to all of them.

Case report of bacteremia due to Neisseria mucosa.

Neisseria mucosa, a Gram-negative diplococcus, is part of normal nasopharyngeal flora. We report a case of bacteremia caused by N. mucosa in a 50-year-old neutropenic patient suffering from non-secretory multiple myeloma stage IIIA. This case underscores that mostly nonpathogenic N. mucosa can cause bacteremia in neutropenic patients who developed mucositis after hematopoietic stem cell transplantation.

Molecular typing of Neisseria perflava clinical isolates.

Multilocus sequence typing and pulsed-field gel electrophoresis were used to type 22 commensal isolates of Neisseria perflava collected by swabbing from neutropenic patients. High genetic diversity was found among our N. perflava clinical isolates.

[Erythropoietin in cancer patients with anemia]. / Erythropoietine chez des patients cancereux anemiques.

OBJECTIVE: The aim of this study is to evaluate the endogenous erythropoietin production in cancer patients with anemia. METHODS: Our prospective study interested 99 cancer patients with anemia from 17 to 80 years old, during the period going from March 2002 to December 2004, and 31 healthy individuals with anemia caused by iron deficiency. A blood sample was collected from each patient, as well as healthy individuals to measure serum erythropoietin, C reactive protein and ferritin. RESULTS: The increase of serum erythropoietin was significantly lower in patients than in healthy individuals (P < 0.05). 25.2% of our cancer patients have inflammatory anemia and 74.7% presented microcytic anemia associated with increase of serum ferririn and CRP. These values were significantly higher than in healthy individuals (p < 0.05). CONCLUSION: Anemia in cancer patients results from activation of inflammatory system, which inhibit erythropoietin production. Apart from etiologic treatments, anemia can be treated with recombinant human erythropoietin.