Prevalence of infectious multi-drug resistant bacteria isolated from immunocompromised patients in Tunisia.

OBJECTIVES: A retrospective study was conducted in the Bone Marrow Transplant Center of Tunisia during a period of 10 years (from 2002 to 2011) in order to report the prevalence of infectious multi-drug resistant bacteria. METHODS: Bacterial identification was carried on the basis of biochemical characteristics and API identification systems. Antibiotic susceptibility was tested by disc diffusion method on Muller-Hinton agar. RESULTS: During the study period, 34.5% of 142 Klebsiella pneumoniae strains and 11.46% of 218 Escherichia coli strains were extended-spectrum beta-lactamase (ESBL) producers. Also, 32.8% of 210 strains of Pseudomonas aeruginosa were imipenem and/or ceftazidime resistant and 20.75% of 106 strains of Staphylococcus aureus were methicillin resistant. A rising trend was observed for the prevalence of the selected multidrug resistant bacteria. CONCLUSION: These findings may have important clinical implications in prophylaxis and selection of antibiotic treatment. Continuous surveillance is needed, especially for onco-hematological patients.

Valeur diagnostique de la procalcitonine et de la protéine c-réactive chez les patients infectés après greffes de cellules souches hématopoïétiques

Contexte et objectif. Les greffes de cellules souches hématopoïétiques présentent un risque accru d'infection en raison de l'immunosuppression conséquente. Cependant, les meilleurs marqueurs de cette infection restent à déterminer. La présente étude avait pour objectif d'évaluer la performance de deux marqueurs d'infections, la procalcitonine et la protéine C-réactive dans le diagnostic infectieux au décours de la greffe de cellules souches hématopoïétiques. Méthodes. Etude transversale et analytique réalisée auprès des patients greffés ayant présenté des épisodes fébriles (température > 38°C) dans le Centre de Greffe de Moelle Osseuse (Tunis, Tunisie), durant l'année 2014. Les dosages de la protéine C-réactive et de la procalcitonine ont été effectués respectivement sur Cobas 400plus et Cobas e411 (Roche) sur les prélèvements sanguins. Ces dosages ont été complétés par des examens microbiologiques à la recherche des agents infectieux. La valeur diagnostique (sensibilité, spécificité..) de deux marqueurs précités a été utilisée en prenant pour référence l'isolement de l'agent infectieux (bactérie, parasite ou virus). Résultats. 50 prélèvements sanguins de 38 patients enrôlés ont été analysés. Dans l'indication diagnostique du type d'infection, la protéine C réactive a montré une sensibilité de 97% et une spécificité de 7%. En revanche, la procalcitonine a montré une sensibilité de 36% contre une spécificité de 71,5%. Conclusion. La procalcitonine semble être plus spécifique que la protéine C-réactive plus sensible dans la détection de l'infection chez les greffés des celles souches hématopoïétique. Toutefois, une étude multicentrique avec un grand échantillon est à envisager pour mieux établir la performance de deux outils diagnostique analysés

Intraspecific 16S rRNA gene diversity among clinical isolates of Neisseria species.

In the present work, nearly the entire 16S rRNA gene sequences of 46 clinical samples of Neisseria spp. were determined, and the aligned sequences were analyzed to investigate the diversity of 16S rRNA genes in each commensal Neisseria species. Two 16S rRNA types were identified in two Neisseria sicca strains, three 16S rRNA types in five Neisseria macacae strains, fourteen 16S rRNA types in twenty Neisseria flavescens isolates, and fourteen 16S rRNA types in nineteen Neisseria mucosa isolates. The number of nucleotides that were different between 16S rRNA sequences within specie ranged from 1 to 15. We found high intraspecific sequence variation in 16S rRNA genes of Neisseria spp. strains.

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.

Successful treatment of Fusarium solani ecthyma gangrenosum in a patient affected by leukocyte adhesion deficiency type 1 with granulocytes transfusions.

BACKGROUND: Ecthyma gangrenosum (EG) manifests as a skin lesion affecting patients suffering extreme neutropenia and is commonly associated with Pseudomonas aeruginosa in immunocompromised patients. Leukocyte adhesion deficiency I (LAD I) which count among primary immunodeficiency syndromes of the innate immunity, is an autosomal recessive disorder characterized in its severe phenotype by a complete defect in CD18 expression on neutrophils, delayed cord separation, chronic skin ulcers mainly due to recurrent bacterial and fungal infections, leucocytosis with high numbers of circulating neutrophils and an accumulation of abnormally low number of neutrophils at sites of infection. CASE PRESENTATION: We report at our knowledge the first case of a child affected by LAD-1, who experienced during her disease course a multi-bacterial and fungal EG lesion caused by fusarium solani. Despite targeted antibiotics and anti-fungi therapy, the lesion extended for as long as 18 months and only massive granulocytes pockets transfusions in association with G-CSF had the capacity to cure this lesion. CONCLUSION: We propose that granulocytes pockets transfusions will be beneficial to heal EG especially in severely immunocompromised patients.

Outbreak of Acinetobacter baumannii in a neonatal intensive care unit: antimicrobial susceptibility and genotyping analysis.

PURPOSE: We describe an outbreak of nosocomial respiratory infection caused by multi-drug resistant Acinetobacter baumannii in a neonatal intensive care unit (NICU) in Tunis and our investigation to determine the source. METHODS: Between May 2006 and February 2007, 31 infants hospitalized in the NICU of the Centre of Maternity and Neonatology of La Rabta in Tunis developed A. baumannii pneumonia. A case (infected infant) was defined as any patient hospitalized in the NICU during the outbreak period, with clinical signs of pneumonia and isolation of A. baumannii from tracheal aspirate. Ten rectal swabs and 98 environmental specimens were collected for the epidemiological investigation. Thirty-nine A. baumannii isolates were collected: 31 clinical strains from tracheal aspirates (>10(3) colony-forming units [CFU]/mL), 3 environmental strains from incubators, and 5 from rectal swab. For the genotyping method, we used pulsed-field gel electrophoresis using ApaI restriction endonuclease. RESULTS: Thirty-one neonates developed multiple drug-resistant A. baumannii-associated pneumonia with 10 deaths due to A. baumannii infection, 48.4% had very low birth weight (

Hemophagocytic syndrome after hematopoietic stem cell transplantation: a prospective observational study.

The aim of this prospective observational study was to evaluate the incidence of hemophagocytic syndrome (HPS) after hematopoietic stem cell transplantation (HSCT). Between July 2006 and December 2007, all patients who received a HSCT in our institution were included in this study. All the following criteria were needed for the diagnosis of HPS: sustained fever over 7 days; cytopenia (neutropenia and/or thrombocytopenia); presence of more than 3% mature macrophages in bone marrow; hyperferritinaemia (>1,000 ng/mL). During this study, 171 patients received a HSCT (68 allogeneic and 103 autologous). The median age was 32 years (3-62). We observed six cases of HPS (6/68; 8.8%) after allogeneic stem cell transplantation (ASCT): one case of EBV-related HPS, two cases of CMV-related HPS, and three cases with no evidence of bacterial, fungal or viral infections. We observed only one case of CMV-related HPS (1/103; 0.9%) after autologous stem cell transplantation. Four patients died despite aggressive supportive care. To our knowledge, this is the first prospective observational study conducted with the aim to evaluate the incidence of HPS after HSCT. This study provides a relatively high incidence of HPS after ASCT. When sustained fever with progressive cytopenia and hyperferritinaemia are observed, HPS should be suspected, and bone marrow aspirate considered. The rapid diagnosis of HPS and the early initiation of an appropriate treatment are essential for patient management.

Single autologous stem-cell transplantation followed by maintenance therapy with thalidomide is superior to double autologous transplantation in multiple myeloma: results of a multicenter randomized clinical trial.

From April 2003 to December 2006, 195 patients with de novo symptomatic myeloma and younger than 60 years of age were randomly assigned to receive either tandem transplantation up front (arm A, n = 97) or one autologous stem-cell transplantation followed by a maintenance therapy with thalidomide (day + 90, 100 mg per day during 6 months) (arm B, n = 98). Patients included in arm B received a second transplant at disease progression. In both arms, autologous stem-cell transplantation was preceded by first-line therapy with thalidomide-dexamethasone and subsequent collection of peripheral blood stem cells with high-dose cyclophosphamide (4 g/m(2)) and granulocyte colony stimulating factor. Data were analyzed on an intent-to-treat basis. With a median follow-up of 33 months (range, 6-46 months), the 3-year overall survival was 65% in arm A and 85% in arm B (P = .04). The 3-year progression-free survival was 57% in arm A and 85% in arm B (P = .02). Up-front single autologous transplantation followed by 6 months of maintenance therapy with thalidomide (with second transplant in reserve for relapse or progression) is an effective therapeutic strategy to treat multiple myeloma patients and appears superior to tandem transplant in this setting. This study was registered at www.ClinicalTrials.gov as (NCT 00207805).

Bone marrow transplantation without conditioning regimen in Omenn syndrome: a case report.

OS is a non-SCID immunodeficiency characterized by a poor outcome even after BMT. We report here a case of BMT without preparative conditioning regimen, and with a successful engraftment in a five-month-old infant with OS. The patient was transplanted with 15 x 10(8) bone marrow mononuclear cells/kg, from his HLA matched brother, without preparative regimen and GVHD prophylaxis. Immunological status was assessed before and after the BMT, and the engraftment was monitored with microchimerism analysis. Six days after BMT, an acute GVHD involving first the skin, then the liver and gut, complicated the post-transplantation course. An excellent engraftment was confirmed by donor chimerism over 95% respectively at day post-transplantation 30, 60, 90, and 150. The cellular immunity of the patient was restored, and infectious complications decreased after BMT. Later the patient experienced chronic GVHD, and he died on day post-transplantation 246 from GVHD. BMT without conditioning regimen for OS is feasible, but there must be a megadose cell transplantation, and appropriate prophylactic immunosuppressive treatment to prevent acute GVHD.

High-level gentamicin-resistant Enterococcus faecium strains isolated from bone marrow transplant patients: accumulation of antibiotic resistance genes, large plasmids and clonal strain dissemination.

Twenty-six high-level gentamicin-resistant (HLGR) Enterococcus faecium strains colonising neutropenic bone marrow transplant patients were studied. Polymerase chain reaction analysis showed that high-level gentamicin resistance was mediated by the aac(6')-Ia-aph(2'')-Ie gene; the aph(2'')-Id gene responsible for gentamicin resistance was also detected in 16 strains. Multiple antibiotic resistance was related to the presence of aph(3')-IIIa, ant(6)-Ia, erm(B), erm (A) and tet(M) genes. Strains clustered into 18 groups according to their plasmid content as well as 16 pulsed-field gel electrophoresis (PFGE) patterns. Although the majority of PFGE patterns were single isolates, three microclones were identified. Hybridisation showed that in the majority of the strains the aac(6')-aph(2'') gene resided on a large plasmid of ca. 96kb detected only on PFGE gels. Based on these findings, colonisation by HLGR E. faecium strains was a result of either possibly related plasmid spread or strain dissemination.

DNA fingerprinting of a multi-resistant coagulase-negative staphylococci isolated from biomaterials in dialysis services.

BACKGROUND: Coagulase-negative staphylococci (CoNS) have emerged as an important opportunistic pathogen isolated in hospital. Several species of CoNS have been implicated in human infections and disease especially in patients with poor health status. METHODS: A total of 71 clinical strains of CoNS were isolated from dialysis fluid and needles in a dialysis unit and characterized. Susceptibility to antibiotics, biofilm production and molecular typing by pulsed-field gel electrophoresis (PFGE) were achieved. RESULTS: The main isolated CoNS strains were Staphylococcus epidermidis (45%), Staphylococcus hominis (14%) and Staphylococcus haemolyticus (12.7%). The susceptibility profile of all strains revealed high resistance level to penicillin and oxacillin. PCR detection of oxacillin resistance gene (mecA gene) revealed a higher percentage of positive strains than the classic test (ATB Staph). Slime production test was positive in 60.6% of CoNS strains. PFGE analysis showed the presence of 69 restriction profiles clustered in 56 patterns. CONCLUSIONS: Profiles of all isolates were generally heterogeneous, suggesting independent circulation with some evidence of cross-transmission.

Randomized trial of prevention of catheter-related bloodstream infection by continuous infusion of low-dose unfractionated heparin in patients with hematologic and oncologic disease.

PURPOSE: Infection is a serious complication of central venous catheters in immunocompromised patients. Catheter-related infection may be caused by fibrin deposition associated with catheters. Interventions designed to decrease fibrin deposition have the potential to reduce catheter-related infections. The purpose of this study was to evaluate the role of low-dose unfractionated heparin in preventing catheter-related bloodstream infection in patients with hemato-oncological disease. PATIENTS AND METHODS: This study was a randomized, controlled trial in which patients with nontunneled catheters were randomly assigned to receive either intravenous unfractionated heparin (continuous infusion of 100 U/kg per day) or 50 mL/day of normal saline solution as a continuous infusion (control group). Heparin was continued until the day of discharge. Catheter-related bloodstream infection was defined according to Infectious Disease Society of America guidelines. RESULTS: Two hundred and eight patients were randomly assigned. Four patients were excluded after assignment. Ultimately, 204 patients were analyzed. Catheter-related bloodstream infection occurred in 6.8% (7 of 102 catheters) of those in the heparin group (2.5 events per 1,000 days) and in 16.6% (17 of 102 catheters) of those in the control group (6.4 events per 1,000 days) (P = .03). No other risk factors were found for the development of catheter-related bloodstream infection. Four and five patients experienced severe bleeding in the heparin and control groups, respectively (P = .2). We did not observe heparin-induced thrombocytopenia. CONCLUSION: The use of continuous infusion of low-dose unfractionated heparin (100 U/kg per day) can be a practical and economical approach to the prevention of catheter-related bloodstream infection in patients with hemato-oncological disease.

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.