[Pseudomonas aeruginosa and cystic fibrosis: first colonization to chronic infection]. / Pseudomonas aeruginosa et mucoviscidose: "de la primocolonisation a l'infection chronique".

Pseudomonas aeruginosa (Pa) is the most common virulent respiratory pathogen in cystic fibrosis and is characterized by an important capacity of adaptation, adherence and communication. The factors of virulence of Pa play a major part in adherence with the respiratory epithelial cells and in occurrence of infectious episodes. The factors responsible for the transition of first Pa acquisition to the chronic infection are not elucidated yet. The system of secretion of type III and the quorum sensing (QS) play an important role. The QS would intervene in the maturation of the biofilm of Pa, responsible for the "mucoid" phenotype of Pa, associated to a degradation of the respiratory function. We made a retrospective study on the period 1984-2005 within the Center of Cystic fibrosis of Caen allow to determine the percentage of firstly-colonized and chronic infected patients with Pa according to age. At 6 months of life, 11% of the infants were colonized with Pa reaching 48% to 7 years and 85% at the 18 years age. The percentage of chronic children carrying Pa was 0% at 1 year, 11% at 4 years, 44% at 12 years and 74% at 18 years according to the method of Kaplan-Meier. Comparing the period 1984-1994 with that of 1995-2005, the firstly-colonization and the chronic carrying of Pa occurred earlier and significantly during the second period. The current objective, beside the respiratory care, comprises the maintenance of an optimal nutritional statute and, waiting for an effective vaccine, the development of new therapeutic targets in order to attenuate the virulence of the stocks of Pa and as much as possible to delay the age of firstly-colonization and the age of chronic colonization with mucoid Pa.

[Acute respiratory tract infections due to a human metapneumovirus in children: descriptive study and comparison with respiratory syncytial virus infections]. / Infections respiratoires aiguës à métapneumovirus humain chez l'enfant: études descriptive et comparative avec le virus respiratoire syncytial.

BACKGROUND: A new paramyxovirus, the human metapneumovirus was recently isolated. We report the first French cases collected between 2000 and 2002. MATERIAL AND METHODS: Samples were obtained from nasopharyngeal aspirates from children hospitalised for acute respiratory tract infection in hospitals of Caen and Flers in Basse-Normandie. Human metapneumovirus was studied by polymerase chain reaction on negative samples for respiratory syncytial virus, influenza A and B virus, parainfluenza (1, 2 and 3) virus, adenovirus, coronavirus and rhinovirus. Comparison between metapneumovirus virus and respiratory syncytial virus infections was done after matching sex, age and infection month. RESULTS: Twenty-six human metapneumovirus infections were identified. A comparative study of a matched group of children infected by respiratory syncytial virus found no significative difference for hospitalisation motive, clinical criteria and treatment. CONCLUSION: The human metapneumovirus is responsible for typical acute bronchiolitis in children.

[Adenoviral respiratory diseases in healthy children: a study of 116 hospital cases]. / Prise en charge des pathologies respiratoires à adénovirus chez l'enfant immunocompétent: À propos d'une étude rétrospective de 116 enfants hospitalisés.

Adenoviruses most commonly cause respiratory illness; however, depending on the infecting serotype, they may also cause various other diseases. Diagnosis may be difficult to achieve.The clinical findings for 116 children hospitalised with adenoviral infection were studied retrospectively. In 71 children, the diagnosis was based on detection of adenovirus antigen in the nasopharyngeal specimens and in 71 children on viral culture. The clinical picture of adenoviral infection was characterised by high-grade (mean 39°1C) and prolonged fever (mean duration 4,3 days). Upper respiratory and lower respiratory symptoms were the most common infections. Twelve had been admitted to the hospital due to febrile convulsions, 6 had meningitis. Laboratory findings varied from normal values to values seen in bacterial infections. Thus it was difficult to distinguish adenoviral disease from a bacterial disease. Fifty-nine children were referred to the hospital due to infection unresponsive to antimicrobial therapy.Symptoms of respiratory infection caused by adenovirus may range from the common cold syndrome to pneumonia, croup and bronchiolitis. Adenoviruses can be responsible for severe consequences, even in previously healthy children. Studies of the molecular mechanisms of viral infections of the airways could provide important insights into the nature of the inflammatory process involved in asthma and chronic obstructive pulmonary disease. Most infections are mild and require no therapy or only symptomatic treatment. There are at present time no recognised antiviral agents that are effective in treating serious adenovirus disease. The rapid detection of adenovirus antigen in nasopharygeal specimens proved to have a great clinical value in the diagnosis.

[Rhinovirus and acute respiratory infections in hospitalized children. Retrospective study 1998-2000]. / Rhinovirus et infections respiratoires aiguës de l'enfant hospitalisé. Etude rétrospective de 1998 à 2000.

OBJECTIVES: Rhinoviruses are the most common aetiological agents of colds, but the frequency and the severity of other locations of the infection are not well known. This study describes the clinical aspects and the severity of rhinovirus infections in hospitalised children. METHODS: Isolation in culture and a RT-PCR were performed for the detection of rhinovirus in nasal aspirates from hospitalised children from September 1998 to October 2000. A group of 211 children found to be positive for rhinovirus was studied. RESULTS: Rhinovirus-infected children suffered from the following clinical syndromes: 60 (28.4%) upper airway infections, 81 (38.4%) bronchiolitis, 25 (11.9%) pneumonias and 12 (4.7%) acute attacks of asthma. Clinical symptoms were wheezing (32%), ronchi (37%) and 29% of children presented with acute distress respiratory syndrome; 40% of the available chest X-Ray were abnormal. Eight children were hospitalised in the intensive care unit and two children died. Twenty-five children (10.9%) had a nosocomial infection; a dual infection was observed in 19 cases (9%) with the following viruses: RSV (3), influenza (2) parainfluenza (8), adenovirus (2), enterovirus (4); 19 (9%) children had a secondary bacterial infection. Rhinoviruses were detected in nasal aspirates in 112 cases (53%) according to the culture and in the rhinovirus culture-negative samples in 99 cases (47%) according to the RT-PCR assay. CONCLUSION: After eliminating cases of bacterial or viral dual infections, the clinical aspects of rhinovirus infections in children are the following: upper respiratory tract infections (25.6%), bronchiolitis ou bronchitis (25.6%), pneumonia (6.2%), acute attack of asthma (5.7%). The virological diagnosis according to culture is mainly improved by molecular techniques.

[Evaluation of diagnosis and follow-up in screened children with cystic fibrosis in Normandy]. / Evaluation du diagnostic et du suivi de la cohorte normande d'enfants dépistés atteints de mucoviscidose.

The neonatal screening programme in Normandy (France) allowed the formation of a homogenous cystic fibrosis (CF) cohort of 150 children diagnosed between 1980 and 1997. At the time of this retrospective study, 11 were deceased, out of which nine had meconium ileus (eight deaths after surgery, one at 5 years of age). Sixty children born between 1980 and 1993 in the Basse-Normandie region were followed up during a mean 80 months following similar protocols. The mean age at diagnosis was 41 days (SD = 27 d) for infants without meconium ileus. The occurrence of Pseudomonas aeruginosa (P. aeruginosa) infection and chronic colonization was studied using a monovariate followed by a multivariate analysis including the following variables: sex; meconium ileus; anthropometric data at birth and at diagnosis; pancreatic insufficiency; radiological data (Brasfield score); microbiology data at diagnosis; and genetic data. P. aeruginosa infection appeared earlier in children with pancreatic insufficiency (OR = 2.2; p < 0.05) or with radiological abnormalities (Brasfield score < 21) at diagnosis (OR = 3.9; p < 0.05). Meconium ileus (OR = 5.3; p < 0.01), pancreatic insufficiency (OR = 3.8; p < 0.01) and Brasfield score < 21 at diagnosis (OR = 5.6; p < 0.001) were prognosis factors for early chronic P. aeruginosa colonization. In CF children without meconium ileus, the major risk factor found through multivariate analysis for earlier infection and for earlier chronic colonization by P. aeruginosa was a diagnosis delay > 40 days (respectively OR = 4.6; p < 0.001 and OR = 10.4; p < 0.005). These results must be compared with the lower Brasfield score at diagnosis in infants diagnosed after 40 days of life (p < 0.01).

[Severe cutaneous Streptococcus pyogenes infections in the child: results of a multicenter survey]. / Infections cutanées sévères à Streptococcus pyogenes chez l'enfant: résultats d'une enquête multicentrique.

UNLABELLED: To assess pediatric cases of severe cutaneous infections due to Streptococcus pyogenes. Since the beginning of 1980, the incidence of cellulitis and necrotizing fasciitis due to S. pyogenes has increased in adults. Serotyping of obtained isolates are in most cases M1, M3 or M5 protein. PATIENTS AND METHOD: A retrospective (1990-2000) survey was carried out in pediatric hospital centers. RESULTS: Three cases of necrotizing fasciitis and 15 of cellulitis were observed. In 30% of the cases, vancella lesions were associated; in the other cases, minor wounds were the site of the infection. Bacteriologic diagnosis was made by local samples in 14 cases; blood cultures were positive in four cases. In 11 cases, initial intravenous treatment consisted of third generation cephalosporin, in six cases of penicillin M or G and in one case of fusidic acid. In the second time, penicillin M was perfused in the majority of the cases. Mean duration of intravenous antibiotics perfusion was 15 days. There were no sequelae or death in this survey. CONCLUSIONS: Despite this study had limited epidemiological characteristics, it confirms that these two infections are rare. The frequency is probably underestimated, due to the difficulty in performing a diagnosis. The major site of infection was the varicella lesion. These two infections are so similar that it is frequent to mistake one infection for the other. Nonsteroidal anti-inflammatory drugs and site of infections did not influence prognosis. The treatment of cellulitis is penicillinotherapy whereas in necrotizing fasciitis early major surgery is often correlated with the rate of survival.

[Viral co-infections in immunocompetent infants with bronchiolitis: prospective epidemiologic study]. / Co-infections virales lors des bronchiolites du nourrisson immunocompétent: étude prospective épidémiologique.

The nature of viral infection was prospectively investigated in 202 immunocompetent infants with bronchiolitis. Nasal aspirates were evaluated by immunofluorescence assay, viral isolation technique and polymerase-chain-reaction-hybridization assay. In 55 infants (27%) more than one respiratory virus were detected. A Rotavirus was found in 40 infants (20%), without any relationship with the respiratory viral status, respiratory syncytial virus being the main virus (46/55), and the association of respiratory syncytial virus and adenovirus being the most frequent (21/55). No difference was found between monoviral infections on the one hand and simultaneous viral infections on the other hand according to age, weight, neonatal disease, past history of personal or familial atopy, central temperature, Silverman's index, oxygen dependency, length of hospitalization, microbiology data. There was no indication that simultaneous virus infections were associated with an increased severity of the bronchiolitis in immunocompetent infants.

[Mucoviscidosis: progress in the diagnosis and management]. / La mucoviscidose: progrès dans le diagnostic et la prise en charge.

Cystic fibrosis (CF) is the most common severe autosomal recessive disorder amongst Caucasian populations. We have learned a great deal on CF during the past 20 years, mainly with the identification of the CFTR gene in 1989. In the same time, improvements in the therapeutic management dramatically changed its clinical outcome: while in 1946 the median survival was 4-5 years, in 2,000, it reaches 30 years in reference centers. Since the prognosis depends on respiratory functions, a large number of clinical trials were designed to improve them; medical, physiotherapic, and surgical interventions such as a bipulmonary grafts allowed to slow the natural decline of respiratory functions. Early diagnosis and maintaining optimal nutrition such as bipulmonary grafts allowed to slow the natural decline of respiratory functions. Early diagnosis and maintaining optimal nutrition are two other determining factors of prognosis. Nowadays the next step is to resolve the problem of the benefit of gene therapy but no significant progress was observed in that field for the past five years.

Detection of viral, Chlamydia pneumoniae and Mycoplasma pneumoniae infections in exacerbations of asthma in children.

BACKGROUND: A high frequency of virus infections has been recently pointed out in the exacerbations of asthma in children. OBJECTIVES: To confirm this, using conventional and molecular detection methods, and expanding the study to younger children. STUDY DESIGN: One hundred and thirty-two nasal aspirates from 75 children hospitalized for a severe attack of asthma were studied (32 infants, mean age 9.1 months; and 43 children, mean age 5.6 years). According to the virus, a viral isolation technique, immunofluorescence assays (IFA) or both were used for the detection of rhinovirus, enterovirus, respiratory syncytial (RS) virus, adenovirus, coronavirus 229E, influenza and parainfluenza virus. Polymerase chain reaction (PCR) assays were used for the detection of rhinovirus, enterovirus, RS virus, adenovirus, coronavirus 229E and OC43, Chlamydia pneumoniae and Mycoplasma pneumoniae. RESULTS: Using IFA and viral isolation techniques, viruses were detected in 33.3% of cases, and by PCR techniques, nucleic acid sequences of virus, Chlamydia pneumoniae and Mycoplasma pneumoniae were obtained in 71.9% of cases. The combination of conventional and molecular techniques detects 81.8% of positive samples. Two organisms were identified in the same nasal sample in 20.4% of the cases. The percentage of detections was higher (85.9%) in the younger group than in the other (77%). The most frequently detected agents were rhinovirus (46.9%) and RS virus (21.2%). Using PCR rather than conventional techniques, the detection rates were increased 5.8- and 1.6-fold in rhinovirus and RS virus infections, respectively. The detection levels of the other organisms are as follows: 9.8, 5.1, 4.5, 4.5, 4.5, 3.7, and 2.2% for enterovirus, influenza virus, Chlamydia pneumoniae, adenovirus, coronavirus, parainfluenza virus, and Mycoplasma pneumoniae, respectively. CONCLUSION: These results confirm the previously reported high frequency of rhinovirus detection in asthmatic exacerbations in children. They also point out the frequency of RS virus detection, and emphasize the fact that PCR assays may be necessary to diagnose respiratory infections in asthma.

[Epidemiology of viral infection and asthma]. / Épidémiologie de l'infection virale et asthme.

The first epidemiological data concerning viruses and asthma were obtained in the 1970s and 1980s by viral isolation and serology. Viral infection can be identified in 24 % to 31.9 % of children, and in 13.3 % of adults. The three most frequent viruses are rhinovirus (RV), respiratory syncytial virus (RSV), and parainfluenza viruses (PIV), detected in 8.8 %, 6.4 % and 6 % of cases, respectively. Due to its amplifying properties, the use of PCR increases the frequency of viral detection, and appears particularly appropriate in asthma where the viral load can be reduced. In a study of bronchiolitis, RSV, PIV3, AdV and RV were identified in 39.3 %, 4.3 %, 1.4 % and 3.9 % of cases, respectively, by IF or culture, and in 62.4 %, 8.3 %, 10.8 % and 12.6 % of cases, respectively, by PCR. Two recent epidemiological surveys used molecular diagnosis in asthma attacks. In a series of 61 adults, 27 (44 %) infections were identified: 16 RV, 4 CV OC43, 3 PIV, 1 RSV, 1 VI, 1 Chlamydia psitacci. In children, viral infection was detected in 226 cases (77 %) : 84 RV, 38 CV, 21 IV, 21 PIV, 12 RSV. We have performed a short retrospective survey for 1997, using molecular biology, on 39 nasal aspirates from children consulting for asthma or wheezing bronchitis. Testing for respiratory viruses by conventional techniques identified 8 (20.5 %) viral infections: 3 RV, 3 RSV, 1 IBV and 1 VPI2. After nucleic acid extraction, PCR-hybridization techniques were applied to these samples to detect RSV, AdV, RV, CV 229E, CV OC43, CP and MP sequences. Twenty six aspirates (54 %) were positive only on molecular biology techniques: 11 RSV, 12 RV, 2 enterovirus, 1 CV OC43. Overall 34 (82 %) viral infections were detected in these children, and a mixed RSV-RV infection was identified in 6 cases. Compared to the studies reported in the literature, we observed the same predominance of RV infections, more RSV infections, probably related to the use of PCR, and a lower incidence of CV infections.

Detection of respiratory syncytial virus, parainfluenzavirus 3, adenovirus and rhinovirus sequences in respiratory tract of infants by polymerase chain reaction and hybridization.

BACKGROUND: Immunofluorescence assay (IFA) of viral antigens in nasal aspirates is largely used for the diagnosis of respiratory syncytial virus (RSV), parainfluenzavirus (PIV) type 3 and adenovirus (AdV) infections, whilst rhinovirus (RV) are detected by virus isolation technique (VIT) only. Using the two techniques, IFA and VIT, a significant number of specimens remain negative in spite of clinical and epidemiological presumptions of viral infection. OBJECTIVES AND STUDY DESIGN: The polymerase chain reaction (PCR) should improve the sensitivity of viral detection in clinical specimens. From October 1995 to March 1996, 277 nasal aspirates from hospitalized infants were tested simultaneously by IFA, VIT, polymerase chain reaction and hybridization with a DNA enzyme immunoassay (PCR-EIA) for RSV, PIV-3, AdV and RV. RESULTS: RSV were detected in 177 (64%) samples, PIV-3 in 23 (8%), RV in 40 (14%), and AdV in 30 (10%). PCR-EIA detected RSV in more samples 173 (62%) than IFA/VIT: 109 (39%) (P < 10(-7)). In most cases (79%), RSV-infected infants had lower respiratory tract disease, and routine and PCR techniques were positive. Out of the 23 PIV-3 infections, 12 were IFA/VIT- and PCR-EIA-positive, and 11 IFA/VIT-negative and PCR-EIA-positive. For RV, 35 (87%) specimens were PCR EIA-positive and 11 (27%) culture-positive; for AdV 30 samples were PCR-EIA-positive and four were culture-positive. Simultaneous viral infections were revealed in a significantly higher proportion than in conventional techniques: 18% (50/277) versus 2.5% (7/277); P < 10(-7). One RSV infection in four was associated with the presence of another virus, mainly PIV-3 (16 cases) and AdV (13 cases). CONCLUSIONS: PCR-EIA detects more positive-specimens than IFA/VIT, 1.5 times more for RSV, 1.9 for PIV-3, 4 for RV and 10 for AdV, respectively. This increased sensitivity of viral detection by PCR-EIA compared to the IFA/VIT could suggest that samples containing low levels of virus are missed by routine methods IFA/VIT, and consequently, RSV or PIV-3, and above all RV or AdV are overlooked as agents of respiratory diseases. However, apart from the fact that the economic and convenient aspects of virus diagnostic cannot be missed, it is difficult to answer the following questions: what is the meaning of the detection of a viral sequences in nasal aspirates of infants, or may PCR have detected virus in patients who would not developed disease?

Detection of respiratory syncytial virus by reverse transcription-PCR and hybridization with a DNA enzyme immunoassay.

Nasal aspirates from 238 infants hospitalized with acute respiratory infections during the winter of 1994 and 1995 were tested for respiratory syncytial virus (RSV) by immunofluorescence assay (IFA) and the viral isolation technique (VIT) and by two PCR and hybridization methods: reverse transcription PCR 1 (RT-PCR1), which amplifies the RNAs of all RSV strains, and RT-PCR-2, which allows subgroup classification of RSV. RT-PCR-1 and RT-PCR-2 detected viral sequences in 56.7% (135 of 238) and 48.3% (115 of 238) of the samples, respectively, while only 80 (33.6%) samples were found to be positive by IFA and VIT. Of the PCR-positive specimens, 57 were missed by these routine techniques in RT-PCR-1 and 45 were missed in RT-PCR-2. Although the RSV-PCR-1 and RSV-PCR-2 techniques amplified two different sequences of the RSV genome, they gave similar results for 218 (91.6%) nasal aspirates. Compared with conventional methods, the sensitivity, specificity, and agreement were 97.5, 63.9, and 75.2%, respectively, for RT-PCR-1 and 89.7, 71.9, and 77.7%, respectively, for RT-PCR-2, and for these two RT-PCR assays, the positive predictive value (PPV) and the index of agreement (kappa) were comparable and moderate, respectively: PPV was 57.8% and kappa was 0.52 in RT-PCR-1, and PPV was 60.9% and kappa was 0.54 in RT-PCR-2. However, there was a perfect correlation between the two RT-PCRs, with a PPV of 100% and an excellent index of agreement (kappa = 0.88). Therefore, most RT-PCR results were really true positive, and VIT and IFA, which missed some of them, appeared to be less sensitive.

A cross-sectional study of plasma and urinary aluminum levels in term and preterm infants.

High aluminum levels have been reported in sick and intravenously fed premature infants; however, aluminum is a ubiquitous pollutant of food. This study compares the usual aluminum levels of healthy newborns from birth to the third month of life with those of enterally fed premature infants free of renal failure. Plasma and urine concentrations were determined 66 times in full-term newborns (n = 58), 56 times in a group of preterm infants whose gestational age at birth was 28 to 32 weeks (n = 36) and 54 times in another group of preterm infants whose gestational age at birth was 33 to 36 weeks (n = 50). Daily aluminum intakes (+/- SE) of the full-term infants and the two groups of preterm infants were 0.42 +/- 0.05, 0.64 +/- 0.03, and 0.52 +/- 0.03 mumol/kg per day, respectively (p = .05). Plasma aluminum levels were 0.29 +/- 0.05, 0.49 +/- 0.06, and 0.39 +/- 0.05 mumol/L (p = .007); urine excretion levels were 0.80 +/- 0.12, 0.77 +/- 0.21, and 0.78 +/- 0.2 mumol of aluminum/mmol of creatinine (p value not significant). Although the metabolic consequences of the high aluminum intakes and blood levels we have observed in very low birth weight infants remain to be assessed, these results suggest that more attention should be paid to the aluminum status and intake of healthy premature babies.