Acquisition nosocomiale de bactéries multirésistantes dans un service de néonatologie : étude prospective et analyse des facteurs de risque

A systematic analysis of weekly nasal and rectal swabs was carried out in a neonatal unit in order to detect colonization with multiresistant bacteria (MRB).

PATIENTS AND METHODS

During a 6-month period, rectal and nasal samples were taken in 187 consecutively hospitalized newborns, the day of the admission (day 0) and every week until discharge, in order to detect MRB, mainly methicillin-resistant coagulase negative staphylococci (MRCoNS), Staphylococcus aureus and multi-resistant Gram-negative bacilli.

RESULTS

Among 187 infants, 50 were already colonized at entrance and excluded from the study. In others, 49 (35%) were colonized by at least one MRB, with a total of 71 strains isolated. The most frequent was MRCoNS, especially Staphylococcus epidermidis (66.1%). Gram-negative bacilli accounted for 9.8%. Colonization began earlier with MRCoNS than with Gram-negative bacilli, 7.8 +/- 6 vs. 15.5 +/- 16 days, P=0.004, and finished earlier 22.7 +/- 15 vs. 38.5 +/- 16 days, P=0.03. Colonized children exhibited by univariate analysis a lower birth weight, more frequent parenteral nutrition or previous hospitalization in a neonatal unit and a younger age at admission. Odds ratio for colonization were 4.06 for prematurity and 43.83 for a previous hospitalization. MRCoNS at days 15 (P <0.05) and 22 (P <0.05) were correlated with the empiric use of antibiotics. No nosocomial infection occurred during the study.

CONCLUSION

A high rate of newborns were colonized with MRB in our unit, especially MRCoNS, acquired earlier than Gram-negative bacilli, with a favoring action of empiric antibiotherapy.

New Devices Designed to Improve the Long-Term Results of Endovascular Treatment of Intracranial Aneurysms. A Proposition for a Randomized Clinical Trial to Assess their Safety and Efficacy

SUMMARY

Endovascular coiling can improve the outcome of patients with ruptured intracranial aneurysms, but angiographic recurrences are frequent compared to surgical clipping. New coils or devices have been introduced to improve long-term results of endovascular treatment but none have been the object of a valid clinical trial. We have proposed a multicentric randomized double-blind study comparing radioactive and standard coil occlusion of aneurysms. The purpose of this article is to review issues that are specific to the design of clinical trials to assess embolic agents that could improve the long-term efficacy of endovascular treatment of intracranial aneurysms. The proposed trial is a randomized, multi-center, prospective, controlled trial comparing the new generation coils to standard platinum coils. Blinding, if at all possible, is preferable to minimize bias, at least for follow-up angiographic studies that should cover a period of 18 months. All patients with an intracranial aneurysm eligible for endovascular treatment would be proposed to participate. The study would enrol approximately 500 patients equally divided between the two groups, recruited within two years, to demonstrate a decrease in the recurrence rate, the primary outcome measure, from 20% to 10%. Secondary outcome measures should assure that complications, initial clinical and angiographic results remain unchanged. Independent data safety and monitoring committees are crucial to the credibility of trials and to ensure scientific rigor and objectivity. The scientific demonstration of an improved long-term efficacy, without significant compromise regarding safety, is mandatory before considering the widespread use of a new embolic device for the endovascular treatment of aneurysms.

A randomized trial on the safety and efficacy of endovascular treatment of unruptured intracranial aneurysms is feasible

SUMMARY

The safety and efficacy of endovascular treatment of unruptured intracranial aneurysms remain undetermined. A randomized trial may be the best way to demonstrate the potential benefits of endovascular management. We propose a randomized, prospective, controlled trial comparing the incidence of subarachnoid haemorrage of patients treated by endovascular coiling as compared to conservative management. We would also study a composite outcome combining SAH and the morbidity of treatment. All patients with one or more unruptured aneurysm >> 3 mm eligible for endovascular treatment would be proposed to participate. The study would be conducted in 40-50 centres. The entire study would enrol 1800 patients, recruited over three years and followed for five years, but would be preceded by a feasibility study on 200 patients. A randomized trial comparing endovascular and conservative treatment could have an important impact on the clinical management of intracranial aneurysms.

A special report: suggested procedures for international unrelated donor search from the donor registries and quality assurance working groups of the World Marrow Donor Association (WMDA)

This special report details the World Marrow Donor Association's recommended procedures regarding the international search for an unrelated donor for hematopoietic stem cell transplantation. The responsibilities of the national hubs, transplant center and donor registry staff are outlined for all actions associated with the preliminary search, formal search, donor confirmatory typing and final donor selection.

In vitro combined bactericidal activity of cefpirome and glycopeptides against glycopeptides and oxacillin-resistant staphylococci

Infections caused by coagulase-negative staphylococci are becoming increasingly important, particularly those of nosocomial origin, as the organisms are frequently multi-resistant. New antimicrobial strategies are needed. The bactericidal activity of a combination of cefpirome with either vancomycin or teicoplanin against 12 strains of methicillin-resistant staphylococci with a decreased susceptibility to teicoplanin was determined in vitro by a time killing method. Strains Mu3 and Mu50 of Staphylococcus aureus were also studied. Cefpirome (0.125-0.5 x MIC) combined with vancomycin (0.25-1 x MIC) or teicoplanin (0.125-1 x MIC) acted synergically against 12 isolates over 18 h in most cases. A synergistic killing effect was also observed with the Mu3 and Mu50 strains of glycopeptide-intermediate S. aureus but over a longer period.

[Role of thiamphenicol in the treatment of community-acquired lung infections]

Streptococcus pneumoniae and Haemophilus influenzae are the two main pathogens responsible for bacterial respiratory tract infections. Their antimicrobial susceptibility to antibiotics like beta-lactams, macrolides or fluoroquinolones has been largely studied, while it remains less known to other antibiotics like thiamphenicol, erythromycin, cotrimoxazole or tetracycline, often used in developing countries due to their availability. In this study, the activity of chloramphenicol and thiamphenicol on different respiratory tract pathogens was found to be equivalent. However, thiamphenicol was better in detecting resistant organisms. One hundred S. pneumoniae among which 69% had reduced susceptibility to penicillin (PRSP) and 87 H. influenzae isolates, 39.1% producing beta-lactamase, were recovered from sputum cultures in children. All H. influenzae and all penicillin susceptible S. pneumoniae strains were sensitive to thiamphenicol. Susceptibility of penicillin sensitive S. pneumoniae to erythromycin, cotrimoxazole and tetracycline was 70.9%, 83.9%, and 90.3% respectively. Susceptibility of PRSP to thiamphenicol, erythromycin, cotrimoxazole and tetracycline was 68.1%, 7.2%, 17.4% and 44.9% respectively. Thiamphenicol and chloramphenicol are still active against respiratory pathogens.

Donor and liability insurance of donor registries, donor centers, and collection centers – recommendations

The article presents views and recommendations of the World Marrow Donor Association regarding the need for donor and liability insurance for hematopoietic stem cell donor registries, and donor and collection centers.

Pneumonies communautaires et infection grippale

Children without chronic or serious medical conditions are at increased risk for hospitalization during influenza seasons, mainly with respiratory tract infections. But influenza virus infections frequently remain undiagnosed, even in hospitalized patients. We prospectively studied the rate of concomitant and preceding influenza infections in children hospitalized with a community acquired pneumonia (CAP).

POPULATION AND METHODS

All 1-15-year-old children with CAP requiring hospitalization between 1st April 2000 and 2002 had nasopharyngeal aspirate for viruses, immunofluorescence and serologies for respiratory pathogens. The peak of influenza IgG measured by complement fixation (CF) is transient, and a titer of 1/64 or more indicates an acute influenza infection in the preceding weeks. Children with chronic disease were excluded and a control group of patients from outpatient clinic was measured.

RESULTS

Among 33 previously healthy children (age 4.9 years, range 1.2-14 years), 8 had a pneumococcal pneumonia, 10 a pneumonia caused by Mycoplasma pneumoniae (MP), 1 by Chlamydia pneumonia, and 8 of unknown origin. In six patients immunofluorescence was positive: Respiratory Syncitial Virus, 2, Adenovirus, 1 and Influenza A, 3 (including a patient with concomitant MP infection). Thirteen of the 33 children (39.4%) had evidence of a recent influenza A infection with CF ab > or = 1/64: with pneumococcal pneumonia, 5/10 with MP pneumonia, 3/8 with unknown origin pneumonia, 9/13 of these previous influenza infections being clinically inapparent. Only 1/30 children of control group (3.3%) had CF ab > or = 1/64.

CONCLUSION

In this study, influenza infection is the direct cause of CAP of children in 12% of cases. In other children with CAP, 39.4% of patients had an influenza infection in the preceding weeks which leads to secondary infection caused by Streptococcus pneumoniae or by MP or other pathogens.

[Ciprofloxacin after clinical failure of beta-lactam antibiotics in children with salmonellosis]

BACKGROUND

Children with enteric fever or severe salmonella infections are usually treated with beta-lactam antibiotics, particularly ceftriaxone. Due to their poor penetration into cells, beta-lactam antibiotics, even if active in vitro, are sometimes clinically ineffective because they cannot reach the intracellular sites of Salmonella multiplication.

OBJECTIVES

To evaluate in a retrospective study usefulness, efficacy and safety of oral ciprofloxacin in patients with severe salmonellosis and clinical failure of ceftriaxone or beta-lactam antibiotics.

PATIENTS AND METHODS

From July 1, 1995 to 2000, the bacteriology laboratory of a French pediatric hospital had identified 215 patients aged between 1 month and 15 years with positive blood or stools for Salmonella sp, 113 of them requiring hospitalization due to their clinical symptoms. Three were excluded for sickle-cell disease or poor nutritional status. None of the 110 strains (including 4 S. typhi, 51 S. typhimurium, 25 S. enteritidis, 6 S. hadar and 5 S. heidelberg) isolated was resistant to ceftriaxone or ciprofloxacin. Forty-one of the 110 strains (37.3%) produced a beta-lactamase. Twelve patients had a rapid recovery without antibiotic treatment, and 98 (mean age 3.9 years) were given antibiotics (ceftriaxone in 91 and amoxicillin in 7) for dysentery (43%), shock (15%) or persistent high fever and severe diarrhea (42%).

RESULTS

In 72 children (mean age = 3.6 years) ceftriaxone treatment (amoxicillin in 5) for 5 or 7 days was rapidly effective: apyrexia was obtained in 1.5 day after the start of treatment and the number of stools per day was 4 or less in 2.2 days. Two to 3 weeks after clinical recovery, asymptomatic carriage was present in 22/38 patients. In the 26 other patients ceftriaxone (amoxicillin in 2) treatment was clinically ineffective, despite good in vitro activity, and was switch for oral ciprofloxacin (20 mg kg(-1) d(-1), 5 days) after 2 to 7 days of lasted fever and/or severe diarrhea. Clinical improvement with ciprofloxacin was obtained in less than 48 h. The strains involved in these 26 patients included the 4 S. typhi and 15 S. typhimurium (P < 0.05), 13/15 (P < 0.01) producing beta-lactamase. Asymptomatic carriage was found in 5/22 patients (P < 0.05) after recovery. None of the patient treated with ciprofloxacin had side effect.

CONCLUSION

In severe salmonellosis, the clinical failure of treatment with ceftriaxone is not rare, particularly in S. typhimurium producing beta-lactamase infection and short treatment with oral ciprofloxacin is safe and allows to obtain a rapid recovery.

Evaluation of a novel monoclonal enzyme immunoassay for detection of Helicobacter pylori antigen in stool from children

BACKGROUND

Reliable non-invasive methods for detection of Helicobacter pylori infection are required to investigate the incidence, transmission, and clearance of infection in childhood.

AIM

To evaluate a new monoclonal enzyme immunoassay (EIA) (FemtoLab H pylori Cnx) for detection of H pylori antigen in stool in a large cohort of children compared with invasive diagnostic methods and the (13)C urea breath test.

PATIENTS AND METHODS

A total of 302 symptomatic previously untreated children (aged 0.5-18.7 years; 148 girls) were recruited at three centres. H pylori status was defined by results of culture, histology, the rapid urease test, and the (13)C urea breath test. Stool samples were investigated locally by the EIA using two different production lots. According to the manufacturer's recommendations, an optical density (OD) of 0.150 was used as a cut off value.

RESULTS

OD values clearly differentiated between the 92 H pylori infected and the 210 non-infected children (median (5th-95th percentiles) 2.729 (0.232->4.000) v 0.021 (0.009-0.075)). Only two false positive and two false negative results occurred, giving a sensitivity, specificity, positive predictive value, and negative predictive value of 98%, 99%, 98%, and 99%, respectively. No significant relation was found between age and OD values in infected or non-infected children.

CONCLUSIONS

The monoclonal stool antigen EIA was excellent in diagnosing H pylori infection in symptomatic children. Accuracy was independent of the laboratory, production lot used, or the child's age. Because only 18/116 children <6 years of age were infected with H pylori, further validation of the test is needed in young infected children.

Glutamate transporters in the guinea-pig cochlea: partial mRNA sequences, cellular expression and functional implications

In the cochlea, glutamate plays a major role in synaptic transmission between the inner hair cell and the primary auditory neurons. Extracellular glutamate concentration must be regulated to prevent excitotoxicity. This regulation is mediated by excitatory amino acid transporters, membrane proteins that remove glutamate from the synaptic cleft. In this study, we investigated the distribution and activity of three excitatory amino acid transporters subtypes in the guinea-pig cochlea: glutamate aspartate transporter, glutamate transporter and excitatory amino acid carrier. A partial messenger ribonucleic acid sequence was determined for each of these transporters, by polymerase chain reaction with degenerate primers, using guinea-pig brain complementary deoxyribonucleic acid as the template. Primers specific for each transporter were then designed and used to screen a dissected organ of Corti complementary deoxyribonucleic acid library. The cellular distribution of each transporter was examined by immunocytochemistry. We investigated the functional consequences of inhibiting glutamate uptake by recording cochlear potentials during intracochlear perfusion with either l-trans-pyrrolidine-2,4-dicarboxylic acid or dihydrokainate. At the end of the electrophysiological session, cochleas were processed for electron microscopy. Only the glutamate aspartate transporter messenger ribonucleic acid was detected in the organ of Corti. Consistently, glutamate aspartate transporter protein was detected in the inner hair cell-supporting cells and in the ganglion of Corti satellite cells. Glutamate transporter and excitatory amino acid carrier were found in the afferent auditory neurons. Only intracochlear perfusions with l-trans-pyrrolidine-2,4-dicarboxylic acid resulted in a dose-dependent decrease in the amplitude of the cochlear compound action potential, leaving cochlear microphonic potential unaffected. After l-trans-pyrrolidine-2,4-dicarboxylic acid perfusion, cochleas displayed a swelling of the afferent endings typical of excitotoxicity. [(-)1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-4,5-dihydro-3-methylcarbamyl-2,3-benzodiazepine], a selective alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist protects the cochlea against l-trans-pyrrolidine-2,4-dicarboxylic acid effect.

Identification of a mouse orthologue of the CED-6 gene of Caenorhabditis elegans

The rapid engulfment of apoptotic cells is a specialized innate immune response used by organisms to remove apoptotic cells. In mammals, several receptors that recognize apoptotic cells have been identified. Previous analysis of the engulfment gene ced-6 in Caenorhabditis elegans (C. elegans) has suggested that CED-6 is an adapter protein that participates in signal transduction pathway that mediates the specific recognition and engulfment of apoptotic cells. Here, we describe our isolation and partial characterization of a mouse cDNA, which is like an orthologue of C. elegans CED-6. PCR screening of mouse cDNA pool with primers designed from the C. elegans CED-6 cDNA sequence resulted in about 300 bp PCR product which was partially sequenced and then screened to a mouse full-length cDNA library. Thus in this study we report the identification of a novel C. elegans CED-6-like orthologue in mouse, which has probable apoptotic like function.

Distribution of the forces produced by motor unit activity in the human flexor digitorum profundus

In humans, the flexor digitorum profundus (FDP), which is a multi-tendoned muscle, produces forces that flex the four distal interphalangeal joints of the fingers. We determined whether the force associated with activity in a single motor unit in the FDP was confined to a single finger or distributed to more than one finger during a natural grasp. The discharge of single low-threshold motor units (n = 69) was recorded at sites across the muscle during weak voluntary grasping involving all fingers and spike-triggered averaging of the forces under each of the finger pads was used to assess the distribution pattern. Spike-triggered averaging revealed that time-locked changes in force occurred under the 'test' finger (that finger on which the unit principally acted) as well as under the 'non-test' fingers. However, for the index-, middle- and ring-finger units, the changes in force under non-test fingers were typically small (< 20 % of those under the test finger). For little-finger units, the mean changes in force under the adjacent ring finger were large (>50 % of those under the test finger). The distribution of forces by little-finger units differed significantly from that for each of the other three fingers. Apart from increases in force under non-test fingers, there was occasional unloading of adjacent fingers (22/267 combinations), usually affecting the index finger. The increases in force under the test finger correlated significantly with the background force for units acting on the middle, ring and little fingers. During a functional grasp, the activity of single units in the FDP allows for a relatively selective control of forces at the tips of the index, middle and ring fingers, but this is limited for little-finger units.

Validation of diffusion methods for macrolide susceptibility testing of Helicobacter pylori

Helicobacter pylori resistance to macrolides is increasing, and the need for susceptibility testing has become crucial. The only standardized method is agar dilution, which is not adapted to clinical practice. The present work aimed: (1) to optimize the technical conditions and to assess the reproducibility of the E-test and disk diffusion method for macrolides susceptibility testing of H. pylori, and (2) to assess the performances of these two phenotypic methods in detecting strains harboring a resistance mechanism to macrolides. We used 191 isolates collected in nine centers of France and Belgium. Phenotypic tests were performed on Mueller-Hinton agar supplemented with 10% horse blood, inoculated with a 2-day-old H. pylori suspension (10(8) CFU/ml), and incubated for 72 hr at 37 degrees C under microaerophilic conditions. The reproducibility studied on two randomly selected strains was better for disk diffusion than for the E-test for both clarithromycin and erythromycin. For a subset of 10 strains, the MICs of erythromycin and clarithromycin did not differ from more than one two-fold dilution when determined by E-test or agar dilution method. The breakpoints were for MICs: 1 mg/L for both clarithromycin and erythromycin and for inhibition diameters, 22 mm for clarithromycin and 17 mm for erythromycin. There was a 100% concordance between susceptibility to erythromycin and clarithromycin. However, the susceptible and resistant populations were better separated by testing erythromycin. Of 34 resistant strains, two lacked the A2142G and A2143G point mutations in 23S rRNA by PCR-RFLP. None of 15 tested sensitive strains were positive for one of these two point mutations. For clinical practice, we recommend to assess macrolide susceptibility of H. pylori by using one of these two phenotypic methods under the described technical conditions.

[Nosocomial bacteremias in pediatrics]

OBJECTIVES

To identify pathogenic microorganisms responsible for hospital-acquired bloodstream infections and to evaluate the associated risk factors in pediatric units, in a case-control study over 30 months from January 1st 1997 to June 30th 1999.

RESULTS

Forty-six of 855 (5.4%) positive blood cultures were attributed to nosocomial infections. They were related to 32 infectious episodes in 28 patients hospitalized for more than 48 hours. The incidence rate was 0.11 per 100 admissions. Gram-positive cocci (n = 14; 38.8%) were the most frequently isolated pathogens (7 cases of Staphylococcus aureus, 5 of coagulase-negative staphylococci), followed by enterobacteria (n = 9; 25%), Pseudomonas aeruginosa (n = 5; 13.8%) and yeasts (n = 5; 13.8%). The major risk factors for hospital-acquired bloodstream infections were: length of stay before positive blood culture (32 +/- 51 days in cases vs 15 +/- 43 days in controls, p < 0.01), presence of central venous catheter [odds ratio (OR): 6.05, 95% confidence interval (CI): 1.87-20.42], number of days with central venous catheter (p < 0.001) and parenteral nutrition (OR: 9.44, 95% CI: 2.03-50.05).

CONCLUSION

Central venous catheter use, length of stay, parenteral nutrition and particularly intravenous lipids are major risk factors for the acquisition of bloodstream infection in hospitalized children.

External power output changes during prolonged cycling with electrical stimulation

This study analysed external power output and physiologic responses in 5 individuals with paraplegia during 40 minutes of electrical stimulation leg cycle exercise. Cycling was performed on a motor-driven isokinetic ergometer that enabled precise determinations of power output. Electrical stimulation was increased to 120-140 mA within the first 5 minutes and remained constant thereafter. Power output increased to 10.7 +/- 3.0 W after 2 minutes, dropped to 5.3 +/- 1.8 W after 6 minutes and subsequently recovered to 8.2 +/- 2.2 and 6.1 +/- 2.3 W after 19.5 and 40 minutes, respectively. Oxygen consumption increased to 0.47 +/- 0.09 l/min after 6 minutes and declined during the second half of the exercise bout. Gross mechanical efficiency after 19.5 minutes was elevated compared with the value after 6 minutes. Heart rate was significantly increased at the end of the trial. The time-dependent variability of power output and physiological responses question the concept of steady state for this form of exercise.

Helicobacter pylori seroprevalence in asymptomatic pregnant women in France

The purpose of our study was to evaluate the incidence of Helicobacter pylori seropositivity in two different populations of asymptomatic pregnant women from different geographic origins during two separate time periods. A retrospective study of consecutive sera obtained from 169 and 302 asymptomatic pregnant women in 1990 and 1999, respectively, was carried out. The global H. pylori seroprevalences for 1990 and 1999 were 21.3 and 21.5% (where P is nonsignificant), respectively. For both periods the H. pylori seroprevalences were significantly higher in non-French pregnant women (66.6 and 50.6%) than in French pregnant women (18.7 and 11.2%) (P = 0.01 and 0.001, respectively). H. pylori seroprevalence in French pregnant women decreased significantly from the first period (18.7%) to the second one (11.2%) (P = 0.03).

[Procalcitonin and viral meningitis: reduction of unnecessary antibiotics by measurement during an outbreak]

OBJECTIVE

Viral meningitis are often treated with antibiotics in emergency because routine analysis of CSF is not always efficient for distinguishing between viral and bacterial infection. The aim of the study was to evaluate the usefulness of procalcitonin (PCT) to reduce antibiotic treatments.

METHODS AND RESULTS

A blood PCT level < 0.5 ng/mL was prospectively used for the diagnosis of viral origin of meningitis in 58 patients (two months-14 years), in which enterovirus was isolated by culture or PCR during an outbreak (May-June 2000). CSF cells range was 10 to 2800/mL (m: 244), PMN 5 to 2464/mL and CSF proteins range was 0.19 to 0.92 mg/dL (m: 0.37). Seventeen patients received antibiotic therapy in admission. In nine patients, PCT (dosage was routinely measured 3/week) result < 0.5 ng/mL was obtained in 24 h and in 48 h in six: treatment was then stopped and children led hospital. In two patients, PCT was > 1 ng/mL because of bacterial coinfection. CSF and PCT values were similar to those of an already published control group.

CONCLUSION

PCT dosage allowed to shorten hospitalization of 4.47 (controls) to 2.06 (patients) days in patients receiving unnecessary antibiotic treatments. During this outbreak, PCT dosage allowed to reduce 40 days of hospitalization.