Biomedical subjects

B Pozzetto

Publications and source records attributed to B Pozzetto.

At least 19 recordsLinked to original sources

PubMed2006

Seminal plasma promotes the attraction of Langerhans cells via the secretion of CCL20 by vaginal epithelial cells: involvement in the sexual transmission of HIV.

BACKGROUND: Heterosexual human immunodeficiency virus (HIV) transmission implies the crossing of the vaginal mucosa by virions present in the semen, potentially using Langerhans cells as transporters. The recruitment of these cells in the mucosa is mediated by the chemokine macrophage inflammatory protein 3alpha (CCL20). The aim of this study was to evaluate the capacity of the semen to induce Langerhans cell recruitment via the production of CCL20 by vaginal epithelial cells. METHODS AND RESULTS: Using a vaginal epithelium model based on the SiHa cell line and human seminal plasma, we demonstrated that semen enhanced the production of CCL20. This secretion was regulated by the nuclear factor-kappaB intracellular signalling pathway. Fractionation of the seminal plasma indicated that the secretion of CCL20 was stimulated by high molecular weight compounds present in semen. Migration assays demonstrated that secreted CCL20 was able to promote the recruitment of Langerhans cell precursors (LCps), which remain permissive to X4 and R5 HIV infection. CONCLUSIONS: Our results demonstrate that epithelial cells respond to factors present in semen by secreting CCL20, leading to the enhancement of LCp recruitment. These data argue in favour of the implication of epithelial cells in the heterosexual transmission of HIV.

Cell Movement↗

PubMed2006

Efficacy of environmental measures to decrease the risk of hospital-acquired aspergillosis in patients hospitalised in haematology wards.

This study evaluated a multidisciplinary strategy to decrease the rate of invasive pulmonary aspergillosis (IPA) among adult patients hospitalised in two haematology wards in a single 560-bed building at the University Hospital of Saint-Etienne. Upgrading of the air filtration system and construction of an air-lock chamber at the entrance to the unit were completed during 1994. In 1995, specific hygienic measures were introduced during hospital building work, including the use of plastic barriers, watering during demolition work, reduction of pedestrian traffic in construction areas, and the wearing of high-efficiency filtration masks by immunosuppressed patients when outside the protected unit. This strategy was evaluated by a prospective survey of IPA cases between 1993 and 2001, coupled with environmental surveillance. The number and risk-level of hospital renovation projects increased between 1995 and 2001 (p < 0.01). In parallel, the rate of IPA decreased globally in the haematology unit from 0.85% (1.19/1,000 patients) in 1993 to 0.28% (0.21/1,000 patients) in 2001. The incidence of IPA decreased significantly between 1993-1996 and 1997-2001 (p 0.02, Mann-Whitney test). These results show that a multidisciplinary approach involving engineers, infection control practitioners, mycologists and clinicians enables IPA rates among patients hospitalised in haematology wards to be significantly decreased.

Environmental Microbiology↗

PubMed2005

Evaluation of a total core antigen assay for the diagnosis of hepatitis C virus infection in hemodialysis patients.

Hemodialysis patients are recognized as a group at high risk of infection with hepatitis C virus (HCV). Therefore, such a population should be screened routinely for the presence of HCV viremia. Since nucleic acid techniques remain expensive and largely unavailable in many laboratories in the developing world, the present study assesses the clinical usefulness of the HCV core antigen enzyme immunoassay for the diagnosis of HCV infection in dialysis patients. One hundred seventy-five dialysis patients were screened for the presence of anti-HCV antibodies and HCV RNA in the serum. One hundred twenty-eight serum samples were collected from the 76 patients who were anti-HCV antibody- and/or HCV RNA-positive. These were evaluated for total HCV core antigen. Of these samples, 55 had sufficient volume to be further tested to quantify HCV RNA by reverse transcription polymerase chain reaction (RT-PCR). Genotyping of the HCV strains showed that the majority belonged to genotype 1b (77%). The HCV core antigen assay showed a sensitivity and specificity of 84% and 89%, respectively. The use of core antigen assay has enabled the early detection of three patients who developed an acute hepatitis C infection during the period of study. A correlation study was undertaken between the quantitative values of viral load, expressed as pg/ml of HCV core antigen in serum, and viral RNA in UI/ml. A significant correlation was observed (Pearson's correlation coefficient: 0.552; P<0.001). In conclusion, detection of HCV core antigen in serum is an inexpensive, reliable, and highly specific assay that can be useful in most laboratory settings to diagnose HCV infection, and especially in laboratories where nucleic acid technologies are not yet available.

Adult↗

PubMed2005

Development of three multiplex RT-PCR assays for the detection of 12 respiratory RNA viruses.

Three multiplex hemi-nested RT-PCR assays were developed to detect simultaneously 12 RNA respiratory viruses: influenza viruses A, B and C, human respiratory syncytial virus (hRSV), human metapneumovirus (hMPV), parainfluenza virus types 1-4 (PIV-1, -2, -3 and -4), human coronavirus OC43 and 229E (HCoV) and rhinovirus (hRV). An internal amplification control was included in one of the RT-PCR assays. The RT-PCR multiplex 1 and the hemi-nested multiplex 1 detected 1 and 0.1 TCID50 of RSV A, respectively, and 0.01 and 0.001 TCID50 of influenza virus A/H3N2, respectively. Two hundred and three nasal aspirates from hospitalised children were retrospectively tested in comparison with two conventional methods: direct immunofluorescence assay and viral isolation technique. Almost all samples (89/91) that were positive by immunofluorescence assay and/or viral isolation technique were detected by the multiplex assay. This method also detected an additional 85 viruses and 33 co-infections. The overall sensitivity (98%), rapidity and enhanced efficiency of these multiplex hemi-nested RT-PCR assays suggest that they would be a significant improvement over conventional methods for the detection of a broad spectrum of respiratory viruses.

Child↗

PubMed2005

[Human immunodeficiency virus type 1 subtypes in cohort of infected patients, Saint-Etienne, France, from 1984 to 2003].

OBJECTIVE: The authors had for aim to study the distribution of HIV-1 subtypes in a cohort of HIV-1 positive patients in the University hospital of Saint-Etienne, France, and to describe the epidemiological characteristics of patients infected with a non-B subtype strain. DESIGN: An epidemiological study was made on 271 HIV-1 positive patients followed up in the Infectious Diseases Department over 20 years. All patients sample were subtyped by serotyping and some samples were also tested by genotyping. RESULTS: Two hundred and sixty-four patients (191 men and 73 women) were found infected by an HIV-1 strain belonging to the M group. After combining serotyping and genotyping results, 195 patients were found infected by a B subtype and 69 by a non-B subtype. Most of the latter strains belonged to an A subtype or related ones. The following factors were shown to be linked to an infection by a non-B strain: being born abroad, having contracted the infection though heterosexual practice, and being a woman. The incidence of non-B strains increased regularly over time (to reach more than 40% in 2003). This progression was especially noted for men born in France with risky sexual behaviour. CONCLUSION: These results indicate that more than 40% of HIV-1 new cases detected in the Saint-Etienne area are related to non-B strains and that strains of A and related subtypes are common in the local population with risky sexual behaviour.

Female↗

PubMed2005

[Epidemiology of nosocomial infections due to Pseudomonas aeruginosa, Burkholderia cepacia and Stenotrophomonas maltophilia].

Non-fermentative Gram negative rods are opportunistic pathogens responsible for nosocomial infections. Using phenotypic markers (serotypes for Pseudomonas aeruginosa and antibiotic susceptibility) allows a preliminary screening of epidemiologically-related strains. However, genotypic markers are necessary to better characterize nosocomial strains for the investigation of outbreaks or cross-transmissions in the hospital setting. Infections due to P. aeruginosa, Burkholderia. cepacia or Stenotrophomonas. maltophilia are usually hospital-acquired and responsible for a high mortality rate as illustrated by the lethality of nosocomial pneumonia due to P. aeruginosa. The severity of these infections is due to the virulence factors of the bacteria and to their occurrence in debilitated patients in whom invasives devices are used. The hospital environment can act as a reservoir with a rate of exogeneous transmission of these bacteria as high as 50% in some studies. To better prevent nosocomial infections related to Gram negative non fermentative rods, the control of the aqueous hospital environment, the strict application of hand disinfection and the investigation of potential cross-transmission in the hospital setting are needed.

Burkholderia Infections↗

PubMed2005

Development and evaluation of Chlamylege, a new commercial test allowing simultaneous detection and identification of Legionella, Chlamydophila pneumoniae, and Mycoplasma pneumoniae in clinical respiratory specimens by multiplex PCR.

This study describes the development and evaluation of a new commercial test, Chlamylege (Argene Inc.), which allows the simultaneous detection in respiratory samples of Chlamydophila pneumoniae, Mycoplasma pneumoniae, and most Legionella species, as well as PCR inhibitors, by using a multiplex PCR and microplate hybridization. The sensitivities of Chlamylege were 1 x 10(-3) IFU, 5 x 10(-2) color-changing units, and 1 CFU per reaction tube for C. pneumoniae, M. pneumoniae, and Legionella pneumophila, respectively. A cohort of 154 clinical samples from patients with documented respiratory infections was analyzed by the kit, including 2 samples from patients with C. pneumoniae infection, 9 samples from patients with M. pneumoniae infection, 19 samples from patients with Legionella species infection, and 114 samples that tested negative for the three pathogens. All the positive specimens were correctly detected and identified by the Chlamylege kit, and no false-positive result was observed with the negative samples. The kit was then evaluated in a pediatric prospective study that included 220 endotracheal aspirates, and the results were compared with those obtained by three single in-house PCR assays. Four specimens were found to be positive for C. pneumoniae and six were found to be positive for M. pneumoniae by using both strategies. The Chlamylege kit detected two additional samples positive for M. pneumoniae and one additional sample positive for a Legionella species other than L. pneumophila; these three samples were shown to be true positive by other techniques. These overall results demonstrate that the Chlamylege assay is sensitive, specific, and convenient for the rapid detection and identification of atypical pathogens in clinical samples from patients with respiratory infections.

Adolescent↗

PubMed2005

The treatment of inguinal hernia in the elderly: open technique or laparoscopic approach?

Well defined and shared quality standards characterize the ideal treatment of inguinal hernia: it should be the least traumatic as regards both the requested type of anaesthesia and the operative technique and the least expensive; it should have the least per-and post-operative morbidity. The chosen technique should be also the easiest to learn and to perform; and his positive results should be the most reproducible. While there are a lot of studies about the comparison between open and laparoscopic surgery, the number of the studies about the specific evaluation of the problem in the aged is very limited. Aim of the paper is to aid in evaluation of the problem in a group of patients, on the basis of the reports and on an initial departmental experience. In conclusion the laparoscopic repair is a complementary choice and not an alternative to the open surgery in the elderly patients.

Adult↗

PubMed2004

Validation of safety procedures for the cryopreservation of semen contaminated with hepatitis C virus in assisted reproductive technology.

BACKGROUND: In France, assisted reproductive technologies involving a hepatitis C virus (HCV)-infected man requires the cryopreservation of potentially infected semen (in order to establish the presence of HCV), hence the need for a safe and secure storage system. We evaluated the safety of high-security straws for the conservation of semen containing HCV RNA under routine conditions. METHODS: Ionomeric resin (IR) straws were filled with seminal plasma spiked with different concentrations of HCV RNA and sealed using a thermo-solder. After a 4% sodium hypochlorite treatment and/or cryopreservation for 7 days in liquid nitrogen, the outside ends of each straw were rinsed with RNAse-free water. RESULTS: No HCV RNA could be detected in any of the water samples. Additional samples included the rinsing water from straws sealed by thermo-solder and from the heating wire used to cut the end of straws containing HCV-positive semen. The latter samples were found positive for both HCV RNA and the protamine-2 gene expressed by spermatozoa. CONCLUSIONS: These results demonstrate the safety of IR straws, the filling system and the thermo-solder for cryopreservation of semen containing HCV in liquid nitrogen. Decontamination of the straw after sealing and the use of disposable scissors to open the straws are strongly recommended.

Cryopreservation↗

PubMed2004

The procedures of hygiene to control hospital-acquired diarrhoea in paediatric wards: a multicentre audit.

An audit was carried out in paediatric wards to study the compliance of healthcare workers (HCWs) to the procedures recommended for the control of hospital-acquired diarrhoea. Thirty-two paediatric wards in the southeast of France participated on a voluntary basis in this prospective observational study after completing a self-administered questionnaire recording measures of hygiene. All the observations were made by the same investigator and focused on preventive procedures: use of single room, handwashing, hand disinfection, overclothing, single-use gloves and masks. Two hundred and seventy patient-HCW contacts were observed, including mainly diapering, temperature measurement, collection of blood sample and catheter care. The isolation of patients in a single room and use of gowns by HCWs were significantly associated with diarrhoea. Whereas handwashing before care was performed by HCWs in more than 95% of all the procedures, the compliance in the use of disposable gloves by HCWs was only of 39.4% for technical procedures (including those with potential exposure to blood) and 20.3% for diapering or temperature measurement. A substantial agreement between reported and observed measures of hygiene was observed for handwashing before contact and hand disinfection with antimicrobial soap before contact. In contrast, this agreement was moderate for use of single room, handwashing after contact, overclothing and wearing disposable gloves after a diaper change. Despite the excellent compliance of HCWs to handwashing, clearer recommendations for the indication and use of disinfectants and disposable gloves are urgently needed.

Child↗

PubMed2004

Evaluation of a prototype HCV NS5b assay for typing strains of hepatitis C virus isolated from Tunisian haemodialysis patients.

Hepatitis C virus (HCV) strains isolated from 68 haemodialysis Tunisian patients exhibiting chronic infection were genotyped targeting the NS5b region of the HCV genome using a prototype assay developed by Bayer HealthCare-Diagnostics (TRUGENE NS5b HCV). The overall results were compared to those obtained with another assay of the same company based on sequencing of the 5' non-coding region (TRUGENE HCV 5'NC genotyping kit). All strains could be typed by the 5'NC typing kit, but only 62 (91; 2%) by the NS5b prototype assay. All the 62 strains typed by both methods exhibited the same pattern at the type level: 57 were type 1, 3 were type 2, and 2 were type 4. At the subtype level, eight strains that gave undetermined results by the 5'NC kit were successfully typed by the NS5b kit; eight additional strains exhibited discrepant results. The overall agreement between the two assays was 74.2% at the subtype level. In conclusion, the NS5b region appears to be much more accurate than the 5'NC region to subtype HCV strains, especially in those isolated from patients attending haemodialysis centres where the subtype distribution suggests frequent nosocomial transmissions.

5' Untranslated Regions↗

PubMed2004

[Prospective follow-up of hospital-acquired diarrhoea in 28 paediatric wards of the south-east part of France during a winter season].

The aim of this study was to evaluate the risk of hospital-acquired diarrhoea during an epidemic period through a prospective multicentre observational study. A systemic investigation of the hospital-acquired diarrhoea (occurring at least 48 h after hospital admission) was conducted through a standardised questionnaire from January to March 1999 in patients of 5 years old or less hospitalised in 28 wards (620 beds) belonging to 20 hospitals located in the south-east part of France. Overall, 241 cases of hospital-acquired diarrhoea were collected, corresponding to a prevalence of 3.3% (3.6% after exclusion of patients admitted for diarrhoea) and a density of incidence of 0.81 per 100 days of hospitalisation. The mean stay duration of hospital-infected patients was greater than 10 days, versus 3.9 days for the other children (P < 0.001). A readmission was required in 27% of the infected children. Rotavirus was involved in 97.8% of microbiologically documented cases (88%). In 50% of the cases, the hospital-acquired diarrhoea was seen in patients with bronchiolitis. Contact isolation measures were prescribed in 88.4% of the cases. These results stress that hospital-acquired diarrhoea represent an important medical and economic load for paediatric units and could be used as reference data to evaluate the impact of preventive measures, especially to reduce readmission and mean stay duration.

Child, Preschool↗

PubMed2004

[High prevalence and incidence of hepatitis C virus infections among dialysis patients in the East-Centre of Tunisia].

Hemodialysed patients are recognised as a group at increased risk of infection with hepatitis C virus (HCV). The aim of this study was to determine the prevalence and incidence of HCV infection among dialysis patients of the east-centre part of Tunisia. Two hundred and seventy-six patients dialysed until 2001 were recruited within seven hemodialysis units located in the cities of Sousse, Monastir and Mahdia. The serum markers of HCV infection were tested over the period of March 2000-December 2002, by a 3rd generation ELISA test for antibodies and by qualitative RT-PCR technique for viral RNA. The prevalence of anti-HCV antibodies and of HCV RNA was 32.6% (90 patients) and 25.7% (71 patients), respectively. Between 1998 and 2002, 20 new infections were documented in five of the seven dialysis units corresponding to an incidence of 2.34% per year, with an average time of contamination after the beginning of dialysis of 4.6 years. If all the infections are assessed to have occurred during dialysis, the density of incidence of HCV contamination was 4.4% per year of dialysis. A high correlation was noticed between the presence of HCV markers in serum and the duration of dialysis (F = 34.15, P < 0.0001). In the absence of other risk factors (transfusion, drug-addiction), these results plead for the nosocomial transmission of the observed HCV infections. A phylogenetic analysis of the E2 hypervariable region of the viral genome is in progress to confirm this assumption.

Female↗

PubMed2004

Influence of blood prestorage conditions and white blood cell filtration on the bacterial load of blood deliberately inoculated with Gram-positive and Gram-negative pathogens.

BACKGROUND AND OBJECTIVES: Currently, the bacterial contamination of blood constitutes one of the major infectious risks of transfusion. The aim of this study was to evaluate the bactericidal effect of blood on various bacterial species and to determine the influence of prestorage conditions and white blood cell (WBC) filtration on the reduction of the bacterial load in isolated red blood cells (RBCs). MATERIALS AND METHODS: The growth kinetics of eight different species of bacteria were studied at 20 degrees C in deliberately contaminated RBC units. Further experiments evaluated the effect of prestorage conditions and WBC filtration on the viability of two model bacteria (Klebsiella oxytoca and Staphylococcus epidermidis) in comparison to previous results obtained with Yersinia enterocolitica. RESULTS: For bacteria susceptible to the bactericidal effect of blood (mainly Gram-negative rods), a reduction of the bacterial load was obtained within 2 h of prestorage at 20 degrees C. When the prestorage period was prolonged beyond 3 h at 20 degrees C, rapid growth was observed with some Enterobacteriaceae. Whereas WBC filtration reduced dramatically the viability of Y. enterocolitica, it had only a minimal effect on the viability of S. epidermidis and K. oxytoca. However, the two latter species of bacteria did not survive prolonged storage at 4 degrees C. CONCLUSIONS: Experiments conducted under realistic conditions are needed to determine whether it would be worthwhile recommending the rapid storage of RBCs at 4 degrees C after WBC reduction of the blood product.

Bacteriological Techniques↗

PubMed2004

Bacterial risk and sperm cryopreservation.

Prior to sperm cryopreservation, French guidelines only recommend viral screening for serological status towards human immunodeficiency virus, hepatitis B and C viruses and Treponema palidum. The probability of semen infection by other bacterial pathogens is not taken into consideration by the current recommendations. The objective of the present study was to evaluate this risk and a strategy to reduce it prospectively. Ninety-six patients consulting for sperm cryopreservation underwent a semen culture simultaneously to cryopreservation. The patients were classified into three groups following semen culture results: negative culture (group 1, 77/96, 80.2%), positive culture with saprophytic agents (group 2, 9/96, 9.4%) and positive culture with pathogen agents (group 3, 10/96, 10.4%). For six patients of the latter group showing a genital infection with Ureaplasma urealyticum, a discontinuous gradient selection performed on the cryopreserved sample was efficient to discard bacteria. These data emphasize the usefulness to cultivate semen simultaneously to cryopreservation and demonstrate the ability to remove some microbial agents from semen before its use in assisted reproductive techniques.

Anti-Bacterial Agents↗

PubMed2004

Surveillance network for herpes simplex virus resistance to antiviral drugs: 3-year follow-up.

Herpes simplex virus (HSV) infections are very common in the general population and among immunocompromised patients. Acyclovir (ACV) is an effective treatment which is widely used. We deemed it essential to conduct a wide and coordinated survey of the emergence of ACV-resistant HSV strains. We have formed a network of 15 virology laboratories which have isolated and identified, between May 1999 and April 2002, HSV type 1 (HSV-1) and HSV-2 strains among hospitalized subjects. The sensitivity of each isolate to ACV was evaluated by a colorimetric test (C. Danve, F. Morfin, D. Thouvenot, and M. Aymard, J. Virol. Methods 105:207-217, 2002). During this study, 3900 isolated strains among 3357 patients were collected; 55% of the patients were immunocompetent. Only six immunocompetent patients excreted ACV-resistant HSV strains (0.32%), including one female patient not treated with ACV who was infected primary by an ACV-resistant strain. Among the 54 immunocompromised patients from whom ACV-resistant HSV strains were isolated (3.5%), the bone marrow transplantation patients showed the highest prevalence of resistance (10.9%), whereas among patients infected by human immunodeficiency virus, the prevalence was 4.2%. In 38% of the cases, the patients who excreted the ACV-resistant strains were treated with foscarnet (PFA), and 61% of them developed resistance to PFA. The collection of a large number of isolates enabled an evaluation of the prevalence of resistance of HSV strains to antiviral drugs to be made. This prevalence has remained stable over the last 10 years, as much among immunocompetent patients as among immunocompromised patients.

Acyclovir↗

PubMed2003

[Epidemic outbreaks control involving Staphylococcus aureus with reduced sensitivity to glycopeptides].

This study describes two epidemic outbreaks involving Staphylococcus aureus with reduced sensitivity to glycopeptides, one in 2000 involving eight patients and the other in 2001-2002 involving 16 patients. These strains were detected rapidly, thanks to routine screening for the offending organisms in the bacteriology laboratory of our hospital. The clonal character of these strains was confirmed by pulsed field electrophoresis. The management of these epidemic outbreaks confirmed (i) the need for systematic adoption of standard precautions, (ii) the importance of circulating information in combating multi-resistant bacteria, as well as the difficulties in transferring colonised patients to different hospital wards, and (iii) the intermittent nature of S. aureus carriage, resulting in a need for prolonged surveillance of colonised and/or infected patients. In addition, our study underlines the value of a multi-disciplinary approach to the management of diffusion of multi-resistant bacteria.

Anti-Bacterial Agents↗

PubMed2003

[Possible implication of student nurses in the transmission of methicillin-resistant Staphylococcus aureus during a nosocomial outbreak].

We report an outbreak of infections due to methicillin-resistant Staphylococcus aureus (MRSA) in a medical unit and the possible implication of student nurses in the dissemination of the epidemic strain. A retrospective epidemiological study looking for hospitalised patients colonised or infected with MRSA from the 1st of June to the 30th of September 2001 in the unit was conducted. An audit of delivered cares and a nasal screening of health care workers (HCW) was performed. Six patients were colonised or infected with a MRSA strain, four of them exhibiting a bacteremia. Six HCW had a nasal carriage of MRSA. Typing of the MRSA strains by pulsed field gel electrophoresis demonstrated an epidemic clone isolated from five of six patients, two student nurses and one HCW not implicated in nursing cares. This report illustrates the risk of nosocomial outbreak linked to cares delivered by student nurses.

Cross Infection↗