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Piérard Denis. Souveraineté. In: Quaderni, n°63, Printemps 2007. Nouveaux mots du pouvoir : fragments d'un abécédaire. pp. 87-89.

Background: Azithromycin maintenance treatment is widely used inCF patients chronically colonized with Pseudomonas aeruginosa (PA). Sev-eral studies have demonstrated that this treatment decreases the prevalenceof S. aureus (SA) colonization, however the development of macrolideresistance in SA is a concern. Methods: We retrospectively reviewed the medical files of all patientswith chronic PA colonization. Patients were divided into 2 groups: treatmentand control. The treatment group consisted of patients who were treatedwith maintenance azithromycin (250 mg in patients with body weight 40 kg, 3x per week). All spu-tum cultures were reviewed for SA positivity and macrolide resistancebefore and during treatment. The control group consisted of patients withoutazithromycin treatment. Their cultures were evaluated in the last 2 years. Results: In total, 60 patients were chronically colonized with PA. Twen-ty-three patients had a maintenance treatment with azithromycin, 30 werenot treated. Seven patients were excluded due to treatment discontinuation. Median age of patients in the treatment group was 28 years (range 12-46years), vs. 20 years (range 2-49 years) in the control group. Median durationof azithromycin maintenance treatment was 6.6 years (range 0.8-8 years). In total, 1652 sputum samples were evaluated: 291 before treatment(median 13 samples per patient, range 7-21), 883 after treatment (median37/patient, range 0-61), vs. 478 in the control group (median 15/patient,range 7-24). Seventeen of 23 patients had SA positive cultures prior to treatment (vs.29 of 30 controls) (p=0.02). In the treatment group, prior to treatment, 142 of 291 isolates (49%)were SA positive. SA positivity rate did not change during treatment (395 of 883 isolates SA positive, 45%) (p=0.5). Prevalence of SA was higher in thecontrol group (345/478, 72%) (p

The presence of integrons and the antibiotic susceptibility profiles of STEC strains isolated in Belgium were analysed. The collection contained 306 strains, of which 225 were human isolates and 81 originated from different food or animal sources. Integrons were detected by PCR in 7.5?% of the tested isolates and all were class 1 integrons. The integron-positive strains all belonged to the human collection. By RFLP, five different types (A, B, C, D, E) were distinguished. The antibiotic-resistance gene cassettes were identified by sequencing representatives of the five different types. Two types of gene cassettes were found in different combinations, one encoding resistance to streptomycin/spectinomycin and the other encoding resistance to trimethoprim. One of the gene cassettes present was the rarely detected aadA23, which was now apparently for the first time reported in Western Europe. Susceptibility profiling of the strains for 11 antibiotics was done by standard disc diffusion assays. Among the 23 integron-positive strains, 17 different antibiotic susceptibility profiles were found. In the 283 integron-negative strains, 24 different antibiotic susceptibility profiles were observed. The majority of these strains were susceptible to all tested antibiotics (n?=?218, 77.0?%). The integron-positive strains were significantly more resistant to eight of the eleven tested antibiotics compared to the integron-negative strains (P

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Rationale: Risk factors for methicillin-resistant Staphylococcus aureus (MRSA) in Cystic Fibrosis (CF) and the impact on CF disease progression are still under debate. Objectives: To study clinical variables associated with MRSA infection and examine impact on FEV1 evolution in CF patients. Methods: A retrospective case-control study from 2002 to 2010, comparing clinical variables and decline of FEV1 of MRSA positive patients with age-and sex matched controls. Results: Thirty of the 165 CF patients (18.2%) had cultures positive for MRSA. Excluding patients under 4 years, the prevalence became 15.2% (23/151). Chronic infection was found in 19/151 (12.6%). Most apparent differences between the groups were: a higher proportion of patients with genotype F508del, less pancreas sufficient patients, more bronchiectasis and more frequent hospitalization in the MRSA group. The FEV1 recorded one year prior to, and at the moment of MRSA infection, was not significantly different from that obtained in controls. However, FEV1 decline over 2 and 6 year periods, were significantly greater in the MRSA group than in the controls. In fact, over a 6 year period FEV1 decline amounted to -2.6% versus -1.3%predicted per year in the MRSA group and controls respectively (p=0.031). Conclusion: Prevalence of MRSA in CF patients averaged 15%, and MRSA infection was shown to be associated with a particular genotype, presence of bronchiectasis and hospitalization. Our spirometric data also clearly show that a MRSA episode entails an FEV1 decline that is almost double that predicted for CF patients who can remain unaffected by MRSA.

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Background : During the influenza A/H1N1 (A/H1N1) pandemic, CF patients (pts) were considered at risk for severe complications, as for seasonal flu. Data on the real impact of A/H1N1 in CF are scare. Aims : To evaluate the impact of A/H1N1 infection in ourCF clinic (150pts) during the Belgian pandemic Oct-Dec 2009, compared to other risk groups, and to the impact of seasonal flu in previous years. Methods : In all CF patients presenting during the pandemic with fever or pulmonary exacerbation, we collected nasal secretions for PCR and culture and/or blood for serology, to detect respiratory viruses including A/H1N1. All pts are annually, correctly vaccinated against seasonal influenza. Results : A/H1N1 was detected in 15 CF pts (9 aged 0_15 yrs, 4 adolescents and 2 above 18 yrs), in 15 (non CF) children with neurodevelopment desease (NDD), and in 79 healthy children. 12/15 CF pts received oseltamivir, wich was well tolerated, 10/15 received antibiotics of which 4/10 intravenously. Only one 9 yrs old CF girl had permanent respiratory decline with chronic hypoxemia. In our previous seasonal influenza survey 17/21 CF pts were hospitalised and 8 had prolonged oxygen need. In NDD pts A/H1N1 led in 3/15 to lethal respiratory complications (SARI) and in 1/15 to lobectomy. 24/79 healthy children had bacterial pneumonia without any permanent sequelae. Conclusion : Chronic respiratory disease and NDD are considered as risk factors for complicated A/H1N1 infection. Our data suggest that A/H1N1 may be less dangerous in CF than seasonal influenza A despite seasonal vaccination. CF pts seem less at risk compared to NDD patients. Vaccination of vulnerable groups remains crucial.

Distribution of Subtilase cytotoxin among clinical verocytotoxin-producing Escherichia coli isolates Glenn Buvens, Sabine Lauwers, Denis Piérard Department of Microbiology and Infection Control, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium Introduction. Verocytotoxin (vtx)-producing Escherichia coli (VTEC) frequently cause sporadic and epidemic foodborne infections ranging from watery to bloody diarrhea, and may lead to the hemolytic uremic syndrome (HUS). A new cytotoxin called Subtilase cytotoxin (SubAB) was recently described in VTEC strains lacking the 'locus of enterocyte effacement' (LEE) pathogenicity island. Intraperitoneal injection of purified SubAB is lethal in mice, and results in widespread microvascular injury, thrombosis, and necrosis in brain, kidneys, and liver. The striking resemblance between the pathology caused by SubAB in mice, and vtx in humans suffering from HUS raises the question whether SubAB contributes to human disease particularly in LEE-negative VTEC. We assessed the role of this virulence factor in Belgium by searching for its presence in both LEE-negative and LEE-positive human VTEC. Methods. A PCR primer pair targeting the subA sequence of the SubAB operon was used to investigate the prevalence of SubAB in 208 VTEC belonging to 75 different serotypes isolated from human stools in our laboratory between 1990 and 2008. All isolates were also examined for the presence of vtx, intimin (eaeA), enterohemolysin (ehxA), and the STEC auto-agglutinating antigen (saa). Results. Seven (3.4%) isolates were positive for subA, comprising serotypes O105:H18 (2 isolates), O113:H21 (two isolates), O162:H28, O178:H19, and OX183:H18 (one isolate each). The vtx1 gene was present in 105 (50.5%) isolates, 73 (35.1%) carried vtx2, and 30 (14.4%) were positive for both vtx1 and vtx2. The eaeA and ehxA genes were present in 143 (68.8%) and 160 (76.9%) isolates, respectively. Thirteen (6.3%) isolates were saa positive. All subA-positive VTEC harboured vtx2 (in combination with vtx1 in two isolates), were LEE-negative, but carried ehxA and saa. One O178:H19 isolate was recovered from a 76-year-old HUS patient, while the other subA-positive isolates were associated with uncomplicated diarrhea. Conclusion. VTEC isolates carrying SubAB are rare in Belgium. The presence of SubAB in an O178:H19 isolate recovered from an HUS patient suggests that this virulence factor might in some cases contribute to the development of HUS when LEE is absent.

OBJECTIVES Respiratory syncytial virus (RSV) infection is a common respiratory infection in young children, occurring as a winter epidemic in temperate climates. A rapid and reliable diagnosis is very important for prompt institution of infection control measures. The purpose of this study was to compare RSV Respi-Strip® (Coris-Bioconcept), an immunochromatographic assay, with "in house" reverse transcriptase (RT) PCR and viral culture. The need for incubation of the sample in extraction buffer before insertion of the strip was also evaluated. METHODS Hundred nasopharyngeal aspiration samples were submitted by the emergency department or the pediatric wards from October 15 to November 21, 2008. For viral isolation 3 cell lines were inoculated to optimize recovery: MRC5 , Hep 2 and LLC-MK2. A multiplex RT-PCR followed by hybridization was performed for the detection of RSV and 8 other respiratory RNA-viruses. RSV-Respi-Strip kit® was used according to instructions from the manufacturer. Briefly, 0.25 ml of nasopharyngeal aspirate was mixed with 0.25 ml of extraction buffer and incubated at room temperature for 0, 1 and 10 min. Subsequently strips were inserted into the buffer suspension and incubated for 15 min prior to reading. To calculate test performance samples were considered as true positive if positive by cell culture or if positive by both PCR and RSV Respi-Strip® in culture negative samples. RESULTS 42% of samples were positive by RSV-Respi-Strip. No discrepancies were detected between results of obtained with the different incubation times of the sample in extraction buffer. 25% were positive by cell culture and 54% were positive by PCR. 45% were considered as true positive - 25 positive by cell culture and 20 culture negative but positive by both PCR and RSV-Respi-Strip. 55% were RSV negative. Sensitivity and specificity of culture, PCR and RSV-Respi-strip® were respectively 25/45 (56%) and 55/55(100%); 45/45 (100%) and 46/55 (84%); 41/45 (91%) and 54/55 (98%). CONCLUSION With a sensitivity of 91% and a specificity of 98% this rapid test method can be relied on to make infection control decisions during RSV epidemics. By omitting the incubation step in extraction buffer, the assay time can be reduced from 25 to 15 minutes.

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Background: The HIV-1 viral load (VL) assay is a major tool in the follow-up of HIV-infected individuals. Classical end-point amplification techniques for VL are more and more replaced by real-time technologies. Initial evaluations of the Cobas Ampliprep/Cobas Taqman (CAP/CTM) v1.0 assay were good but afterwards reports about serious underquantification became available. The aim of this study was to investigate if the underquantification problem is solved with the second version of this CAP/CTM assay. Materials & Methods: 381 consecutive HIV-1 positive samples with VL ?4000 copies/ml with Cobas Amplicor were collected in 3 labs. Only one sample per patient was included. The left over material after routine testing of the original specimen was diluted 1:5 or 1:10, aliquoted and tested in parallel with Cobas Ampliprep/Cobas Amplicor (CAP/CA) v1.5, CAP/CTM v1.0 and v2.0. An absolute difference between the results of two methods of more than 0.7 log copies/ml was defined as moderately discrepant and an absolute difference of more than 0.9 log copies/ml was defined as severely discrepant. Criteria to be fulfilled for considering the new methods equivalent to the routine method were as follows: an absolute difference between CAP/CA and respectively CAP/CTM v1.0 and v2.0 of less than 0.7 log c/ml for at least 95% and less than 0.9 log c/ml for at least 99% of all samples. Mean values (log copies/ml) were compared with the t-test for paired data. Results: One sample appeared severely overquantitated with both Taqman assays (+1.29 and +1.84 log copies/ml with v1.0 and v2.0 respectively). This is probably due to a primer mismatch and underquantification with the CAP/CA assay. The patient's CD4 count and clinical presentation correlate better with the higher VL. This result was considered as an outlier and was not taken into account in our calculations. CAP/CTM v1.0 compared to CAP/CA: 36 (9.5%) samples were moderately and 20 (5.3%) samples were severely underquantitated. 2 (0.5%) samples were moderately overquantitated. The overall mean difference between CAP/CTM v1.0 and CAP/CA was -0.32 log copies/ml. This difference is statistically significant. Although this difference is less than 0.5 log copies/ml, accepted as clinically relevant, it clearly illustrates the underquantification problem. Moreover, the number of moderately and severely underquantitated samples is unacceptable. CAP/CTM v2.0 compared to CAP/CA: No samples were moderately or severely underquantitated. 8 (2.1%) samples were moderately and 3 (0.8%) were severely overquantitated. A mean difference of +0.07 log copies/ml was found with the CAP/CTM v2.0 compared to CAP/CA. This difference is statistically but not clinically significant. Conclusions: The criteria to consider the new method equivalent to the routine method are fulfilled only for CAP/CTM v2.0. In this evaluation the underquantification problem with the first version of the CAP/CTM kit was clearly demonstrated and it seems to be solved with the second version of this kit.

Background and aims: Non-responding and recurrent CA-LRTI are frequent in children and known causes of high morbidity. Documentation of etiology is difficult but important for prevention and treatment strategies. We aimed to document the possibly responsible pathogens. Methods: Retrospective analyses of bronchoalveolar lavage fluid (BAL) (aerobe and viral culture, viral PCR), nasopharyngeal aspirate (viral PCR and culture) and blood culture, for all (otherwise healthy) children, who underwent a flexible bronchoscopy with BAL, for CA-LRTI, from 2005- 2007. Results: 384 children (128 acute non-responding (broncho)-pneumonia, 123 recurrent (broncho)-pneumonia, 92 persistent X-ray abnormalities and 41 persistent wheezers) were included. The median age was 33.1m (range: 1.0-171.6m) and female:male ratio was 1:1.2. 143/384 (37.2%) patients received antibiotics with certainty before BAL. Bacterial cultures were negative in 156/384 (40.6%) patients. BAL-cultures were positive in 227/384 (59.1%) patients and blood cultures in 3/384 (all S. pneumoniae). In BAL, Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae were most often isolated, in respectively 164, 55 and 33 patients. 148/164 (90.2%) H. influenzae strains were not typable, 2 belonged to serotype e and 1 to serotype b. Biotypes 2 and 3 were predominant and 42/164 (25.6%) were ?-lactamase producers. SGT's 23, 19 and 6 were the predominant pneumoccoccal serotypes. In 96/380 (25.2%) patients viral PCR and/or cultures were positive: RSV, parainfluenzavirus type 3 and human metapneumovirus being most isolated. Mixed bacterial/viral infections were found in 62/380 (16.3%) patients. Conclusions: Non-typable H. influenzae was the most isolated pathogen, possibly responsible for the non-responding or recurrent character of the CA-LRTI.

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Introduction: Although pertussis immunisation is recommended for paediatric health care workers (HCW), vaccine uptake remains low and outbreak may still occur. In 2008, a 6 month-old cardiac patient originating from Algeria, developed severe pertussis and was admitted to PICU. Objective: To describe infection control intervention during a pertussis oubreak in our 16 beds paediatric cardiac surgery and 14 beds PICU unit. Methods: Confirmed pertussis case : Positive PCR on nasopharyngeal aspirate (NPA). HCW, patients and parents were interviewed to search for cough and pertussis vaccine status. B. pertussis PCR detection was performed in all unvaccinated direct contact of index case. Serology was performed in unvaccinated contact HCW and parents. Immunisation was proposed to all HCW. Contact patients and parents were given antibiotic prophylaxis and cardiac surgery unit was quarantined for 5 days. Active surveillance was performed for 10 weeks. Résultats: 4/61 and 19/54 HCW had received a pertussis vaccine in surgery and ICU respectively. 151 NPA were performed and 7 (4,6 %) confirmed cases have been identified (2 children, 2 nurses and 3 mothers), 2 of which were symptomatic. No cases were acquired in ICU. No children were identified with pertussis symptoms and 7 HCW had symptoms of cough, one was paroxysmal and one prolonged. No serology was positive (55 performed). Antibiotics treatments or prophylaxis were administered to 38 persons. 82 HCW were vaccinated, 29 and 18 from surgery and ICU respectively. Conclusions: Pertussis outbreak control required drastic containment measures. Pertussis immunisation of HCW should be actively recommanded to avoid outbreaks.

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