Radiographic findings among children hospitalized with severe community-acquired pneumonia.

BACKGROUND: Community-acquired pneumonia (CAP) is a leading cause of childhood death. There are few published reports of radiographic findings among children with severe CAP. OBJECTIVE: To describe chest X-ray (CXR) findings and assess association between these radiographic findings and pneumococcal isolation in children with severe CAP. METHODS: A prospective, multicenter, observational study was conducted in 12 centers in Argentina, Brazil, and the Dominican Republic. Children aged 3-59 months, hospitalized with severe pneumonia, were included. On admission, blood and pleural effusion cultures were performed. Streptococcus pneumoniae was identified according to standard procedures in the respective national reference laboratory. Chest X-rays were taken on admission and read before the culture results were reported. RESULTS: Out of 2,536 enrolled patients, 283 (11.2%) had S. pneumoniae isolated, in 181 cases (7.1%) from blood. The follow radiographic patterns were observed: alveolar infiltrate (75.2%), pleural effusion (15.6%), and interstitial infiltrate (9.2%). Overall, pleural effusion was associated with pneumococcal isolation and pneumococcal bacteremia (P < 0.001). Infiltrates were unilateral (78.7%) or bilateral (21.3%), right-sided (76%) or left-sided (24%), in the lower lobe (53.6%) or the upper lobe (46.4%). Multivariate analysis including patients with affection of only one lobe showed that upper lobe affection and pleural effusion were associated with pneumococcal isolation (OR 1.8, 95% CI, 1.3-2.7; OR 11.0, 95% CI, 4.6-26.8, respectively) and with pneumococcal bacteremia (OR 1.7, 95% CI, 1.2-2.6; OR 3.1, 95% CI, 1.2-8.0, respectively). CONCLUSIONS: Three-quarters of the patients studied had alveolar infiltrates. Upper lobe compromising and pleural effusion were associated with pneumococcal invasive disease.

Hospital-acquired human bocavirus in infants.

Human bocavirus (HBoV) is a respiratory pathogen that affects young children. We screened 511 nasopharyngeal aspirates for hospital-acquired HBoV from infants hospitalised with respiratory infection from January to December 2008. Among 55 children with HBoV infection, 10 cases were hospital-acquired. Compared with the community-acquired cases, coinfection with other respiratory viruses in these patients was uncommon. HBoV should be considered for inclusion in screening protocols for nosocomial childhood respiratory infections, especially in intensive care units.

Performance of indirect immunofluorescence assay, immunochromatography assay and reverse transcription-polymerase chain reaction for detecting human respiratory syncytial virus in nasopharyngeal aspirate samples.

Comparison of the use of indirect immunofluorescence assay (IFA), immunochromatography assay (ICA-BD) and reverse transcription-polymerase chain reaction (RT-PCR) for detecting human respiratory syncytial virus (HRSV) in 306 nasopharyngeal aspirates samples (NPA) was performed in order to assess their analytical performance. By comparing the results obtained using ICA-BD with those using IFA, we found relative indices of 85.0% for sensitivity and 91.2% for specificity, and the positive (PPV) and negative (NPV) predictive values were 85.0% and 91.2%, respectively. The relative indices for sensitivity and specificity as well as the PPV and NPV for RT-PCR were 98.0%, 89.0%, 84.0% and 99.0%, respectively, when compared to the results of IFA. In addition, comparison of the results of ICA-BD and those of RT-PCR yielded relative indices of 79.5% for sensitivity and 95.4% for specificity, as well as PPV and NPV of 92.9% and 86.0%, respectively. Although RT-PCR has shown the best performance, the substantial agreement between the ICA-BD and IFA results suggests that ICA-BD, also in addition to being a rapid and facile assay, could be suitable as an alternative diagnostic screening for HRSV infection in children.

Performance of indirect immunofluorescence assay, immunochromatography assay and reverse transcription-polymerase chain reaction for detecting human respiratory syncytial virus in nasopharyngeal aspirate samples

Comparison of the use of indirect immunofluorescence assay (IFA), immunochromatography assay (ICA-BD) and reverse transcription-polymerase chain reaction (RT-PCR) for detecting human respiratory syncytial virus (HRSV) in 306 nasopharyngeal aspirates samples (NPA) was performed in order to assess their analytical performance. By comparing the results obtained using ICA-BD with those using IFA, we found relative indices of 85.0 percent for sensitivity and 91.2 percent for specificity, and the positive (PPV) and negative (NPV) predictive values were 85.0 percent and 91.2 percent, respectively. The relative indices for sensitivity and specificity as well as the PPV and NPV for RT-PCR were 98.0 percent, 89.0 percent, 84.0 percent and 99.0 percent, respectively, when compared to the results of IFA. In addition, comparison of the results of ICA-BD and those of RT-PCR yielded relative indices of 79.5 percent for sensitivity and 95.4 percent for specificity, as well as PPV and NPV of 92.9 percent and 86.0 percent, respectively. Although RT-PCR has shown the best performance, the substantial agreement between the ICA-BD and IFA results suggests that ICA-BD, also in addition to being a rapid and facile assay, could be suitable as an alternative diagnostic screening for HRSV infection in children.

Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: is the cefoxitin disk diffusion test accurate enough?

We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100% sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92%, respectively, and 98% specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98%, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.

Detection of methicillin resistance in Staphylococcus aureus isolated from pediatric patients: is the cefoxitin disk diffusion test accurate enough?

We evaluated the performance of several methods for the detection of methicillin resistance in Staphylococcus aureus using 101 clinical S. aureus isolates from pediatric patients in a tertiary hospital in Brazil; 50 isolates were mecA-positive and 51 were mecA-negative. The Etest and oxacillin agar screening plates were 100 percent sensitive and specific for mecA presence. Oxacillin and cefoxitin disks gave sensitivities of 96 and 92 percent, respectively, and 98 percent specificity. Alterations of CLSI cefoxitin breakpoints increased sensitivity to 98 percent, without decreasing specificity. Our results highlight the importance of a continuing evaluation of the recommended microbiological methods by different laboratories and in different settings. If necessary, laboratories should use a second test before reporting a strain as susceptible, especially when testing strains isolated from invasive or serious infections. With the new (2007) CLSI breakpoints, the cefoxitin-disk test appears to be a good option for the detection of methicillin resistance in S. aureus.

[Pharmacologic innovations, the fluoroquinolone model]. / Innovations pharmacologiques, le modèle des fluoroquinolones.

OBJECTIVES: Like all the disciplines involved in infectious diseases and antibiotic therapy, pharmacokinetics and pharmacodynamics (PK/PD) of antibiotics have evolved significantly. They include new investigation procedures like in vitro models and new animal models. There is a current trend towards better methods, newer definitions and improved quality of research in this particular field. DEFINITIONS: The current evolution of pharmacology of antibiotics is mainly characterized by the development of pharmacodynamics (PD) which offers the advantage of including microbiology data. New PD parameters have been defined. It is recommended to working groups involved in PK/PD research to compare their results and tend to a consensus on the methods to be used. CONCLUSION: Benefiting from such progress, preclinical phases of PK/PD studies of new molecules as well as revision of older antibiotics permit a rigorous and clinical approach to the use of antibiotics.

[Latest news on fluoroquinolones]. / Dernières nouvelles des fluoroquinolones.

THE AIMS OF NEW FLUOROQUINOLONES: Are to widen the antimicrobial spectrum and eventually reach anaerobic bacteria, to increase the activity on resistant Gram positive bacteria and to enhance the affinity of the molecule for the target enzymes of the bacteria THE EXPECTATIONS WITH THE NEW QUINOLONES: Globally, the tests conducted show far superior activity than that of the agents used for comparison. CONCERNING THE OLDER FLUOROQUINOLONES: Despite the threat of emergence of resistance in pneumococci, questions are raised on the clinical correspondence of the microbiological data obtained, notably with the rates of therapeutic failure, observed in patients exhibiting strains with supposedly high MICs.

[Blood culture update]. / Actualités sur l'hémoculture.

BACKGROUND: Blood culture is one of the most important bacteriological examinations with important clinical and therapeutic consequences. Blood cultures should be ordered in all patients with signs suggesting septicemia, endocarditis or severe infection (pneumococcal pneumonia, bacterial meningitis with bloodstream dissemination). Blood culture methods have evolved considerably over the last twenty years. After using manual methods for many years, read by non-standardized visual methods, the development of media with defined compositions and supplemented to allow growth of bacteria difficult to culture has been associated with the development of automatic blood culture devices. AUTOMATIC DEVICES: These devices have undergone rapid improvement. Semi-automatic devices (Bactec NR-660) were rapidly followed by completely automatic techniques, including four devices currently available: since 1989 Bio-Argos (Rio-Rad) and Bact/Alert (Organon-Teknika) and in 1993, Bactec 9240 (Becton-Dickinson) and Vital (BioMérieux). All these devices allow automatic detection of CO2 produced during bacterial growth. Automatic reading systems provide continuous output avoiding the need for invasive methods and thus the risk of contamination in addition to saving time. Potential application to achieve quantitative blood cultures for intensive care units is in the development stage. CONSEQUENCES: The reliability of these devices is well recognized and their contribution to severe bacterial infection is undeniable. There are certain limitations however related to material cost and the non-identification of the pathogen involved. Molecular biology techniques open new perspectives in this field. The evolution of techniques, definitions, and pathogenic approach to septicemia must be revisited as new infectious situations have been identified at the same time as new investigation tools resulting from considerable technological progress. New methods of blood culture have largely contributed to this progress.

[Nasopharyngeal colonization and antimicrobial resistance of Streptococcus pneumoniae isolated from children with acute rhinopharyngitis] / Colonização e resistência antimicrobiana de Streptococcus pneumoniae isolado em nasofaringe de crianças com rinofaringite aguda.

OBJECTIVE: To determine the prevalence and risk factors for nasopharyngeal colonization by, and to evaluate antimicrobial susceptibility of Streptococcus pneumoniae strains in children with acute rhinopharyngitis. METHODS: We collected nasopharyngeal swab specimens from 400 children aged 3 months to 5 years and with clinical status of acute rhinopharyngitis from June 16, 1997 to May 20, 1998 at the outpatient clinics of two hospitals in the city of São Paulo. Nasopharyngeal specimens were collected pernasally using a calcium alginate swab and plated immediately after collection onto trypticose soy agar with 5% sheep blood and garamicin 5 mcg/ml. Penicillin susceptibility was determined by oxacillin 1 mcg disk screening test and the minimal inhibitory concentration by the E-test. RESULTS: Pneumococci were recovered from 139 children, indicating a colonization prevalence of 35%. The risk factors analyzed indicated that the colonization was more prevalent in children attending day-care centers, children with siblings younger than 5 years, and children with recent use of antimicrobial agents. The prevalence of penicillin non-susceptible strains was of 16 % (20 strains). All strains were intermediately resistant (0.1mcg/ ml

[Epidemiology and management of suspected pneumonia in nursing home residents]. / Epidémiologie et prise en charge des pneumopathies suspectées en maison de retraite.

OBJECTIVE: We conducted a descriptive epidemiology study to examine the conditions of management of infectious lung disease in institutionalized elderly populations (population profile, diagnostic and therapeutic modalities) and to analyze the general and mental consequences in terms of independence (impact of the infectious event on the subject's life style). PATIENTS AND METHODS: A pragmatic survey was conducted by a multicentric observatory composed of 573 general practitioners, practicing in nursing homes. The series included 1790 patients aged over 70 years and residing in nursing homes who developed infectious lung disease over a 10-month period. The MMSE score was used to assess mental status and the Barthel index to assess functional handicap. Each patient was evaluated at the time of the final diagnosis (prescription of an antibiotic or decision for hospitalization) and at most 3 days after the end of this treatment or at discharge from hospital. RESULTS: The elderly population (84 +/- 7 years) was predominantly composed of women. The patients were treated for an acute respiratory infection considered in 30% of the cases to be acute lobar pneumonia. Subgroups of patients were identified for analysis: death (3.7%), x-ray confirmation of the diagnosis (11.5%), hospitalized patients (10.2%). In addition to major deterioration of the general health status, a consequence of the infection more than of the severity of the respiratory symptoms, the development of an acute episode coincided with reduced intellectual functions and onset of a state of confusion. In 70% of the cases, this resulted in a loss of independence of variable importance--simple difficulty for moving around to major functional handicap. The infectious episode was cured or improved (persistence of minor signs not requiring specific treatment) in 94.3% of the cases with appropriate antibiotics: single-drug regimen in 93.7% give per os (75%) or intravenously (25%) using aminopenicillin (with or without a beta lactamase inhibitor) in 80% of the cases. Antibiotic treatment was associated with physical therapy in more than half the cases, and with general conticosteroids in 40%. The treatment scheme was modified in 9.4% of the cases (change of antibiotic in 6%). CONCLUSION: This survey confirms the high risk related to general conditions in elderly institutionalized patients who develop respiratory infection. More than the infection itself, the rapid degradation of the general health status, or decompensation of comorbid states can create life-threatening situations or favor the development of irreversible handicaps.

Guidelines on antimicrobial chemotherapy for prevention and treatment of infections in the intensive care unit.

Severe infections (SIs) in Intensive Care Units (ICUs) constitute difficult therapeutic problems confronting clinicians who deal with severely ill patients. Some SIs are opportunistic infections acquired either in the community or in hospitals, particularly in immunodepressed patients. The great majority of ICU infections are of nosocomial origin. Resistant organisms have led to changing antibiotic therapy in ICU infections. Before microbiology is available, empiric therapy is based on: (i) proper identification of bacterial risks in each infection site; (ii) local surveillance of frequent nosocomial organisms/susceptibility patterns in the ICU; (iii) identification of environmental risk factors and the patient's underlying condition. In documented infection, antibiotic therapy must take into account gram-positive vs gram-negative bacteria or mixed infections, pharmacokinetics/pharmacodynamic parameters of chosen antibiotic(s) and concentrations at the infection site, in order to prevent selection of resistant mutants and to provide the most efficient antibiotic therapy. With increasingly sophisticated intensive care measures, invasive exploratory procedures, and surgical procedures, evolving profiles of hospital infections require updated Guidelines for treatment of severe infections in ICUs. Preventive and therapeutic strategies include control of antibiotic use, and suitable antibacterial treatments which result in shortened hospital stay, improved outcome of hospital infections and significant cost savings.

Treatment and prevention of antibiotic associated diarrhea.

Mild or severe episodes of antibiotic-associated diarrhea (AAD) are common side effects of antibiotic therapy. The incidence of AAD differs with the antibiotic and varies from 5 to 25%. The major form of intestinal disorders is the pseudomembranous colitis associated with Clostridium difficile which occurs in 10-20% of all AAD. In most cases of AAD discontinuation or replacement of the inciting antibiotic by another drug with lower AAD risk can be effective. For more severe cases involving C. difficile, the treatment of diarrhea requires an antibiotic treatment, with glycopeptides (vancomycin) or metronidazole. Another approach to AAD treatment or prevention is based on the use of non-pathogenic living organisms, capable of re-establishing the equilibrium of the intestinal ecosystem. Several organisms have been used in treatment or prophylaxis of AAD such as selected strains of Lactobacillus acidophilus, L. bulgaricus, Bifidobacterium longum, and Enterococcus faecium. Another biotherapeutic agent, a non-pathogenic yeast, Saccharomyces boulardii has been used. In animal models of C. difficile colitis initiated by clindamycin, animals treated with S. boulardii (at end of vancomycin therapy) had a significant decrease in C. difficile colony-forming units, and of toxin B production. In several clinical randomised trials (versus placebo), S. boulardii has demonstrated its effectiveness by decreasing significantly the occurrence of C. difficile colitis and preventing the pathogenic effects of toxins A and B of C. difficile. It has been shown to be a safe and effective therapy in relapses of C. difficile colitis. A good response has been seen in children with AAD, treated by S. boulardii only. In ICUs prevention of AAD remains based on limitation of antibiotic overuse and spread of C. difficile or other agents of AAD should be prevented by improved hygiene measures (single rooms, private bathrooms for patients, use of gloves and hand washing for personnel). In addition the increasing use of biotherapeutic agents such as S. boulardii should permit the prevention of the major side effect of antibiotics, i.e. AAD in at risk patients.

[Resistance and new antibiotic strategies. The problem with staphylococcus]. / Résistances et nouvelles stratégies antibiotiques. Les problèmes des staphylocoques.

MRSA outside the hospital: From a major problem almost exclusively encountered in hospitalized patients, methicillin-resistant Staphylococcus aureus (MRSA) infection has become a cause of skin, soft tissue, and even systemic infections outside the hospital. In order to prevent further spread, patients carrying MRSA (recently hospitalized patients, drug abusers, debilitated subjects, etc) must be identified and the mode of acquisition of MRSA infection. (cross transmission between community and non-hospital care centers) must be recognized. Small colony variants: SCV produce non-pigmented colonies that are 10 times smaller than the usual S. aureus colonies and have particular metabolic and genetic properties. They can cause persistent, recurrent and drug-resistant infections. MRSA in France: Data obtained in a case-control study confirms the selection pressure as well as the important colonization pressure exerted by antibiotics on gentamicin-sensitive strains.

[Resistance and new antibiotic strategies. New antistaphylococcal antibiotics]. / Résistances et nouvelles stratégies antibiotiques. Nouveaux antibiotiques antistaphylococciques.

INJECTABLE SPECTROGRAMIN: Combination regimens using quinupristin/dafopristin with either gentamicin or vancomycin have powerful bactericidal activities (even against quinupristin-resistant strains) against methicillin-resistant Staphylococcus aureus (MRSA) in a model of experimental endocarditis in the rabbit. In clinical trials, quinupristin/dalfopristin is becoming a therapeutic alternative to consider after failure of conventional antistaphylococcal treatments. NEW GENERATION CEPHALOSPORINS: These new cephalosporins, particularly C-3 pyridinium-thiomethyl-cephalosporins, new (3-dithiocarbamoyl) cephalosporins, and a series of new compounds with high affinity for MRSA PLP2a, are particularly active against MRSA and are unaffected by beta-lactamases. A NEW CARBAPENEM: This new antibiotic has a wide bactericidal effect against Gram-positive organisms and is active against MRSA as well as penicillin-resistant S. pneumoniae. NEW FLUOROQUINOLONE DERIVATIVES: In vitro, these new derivatives have been found to be active against MRSA, pneumococci non-sensitive to ciprofloxacin, and Bacteroides fragilis, Mycobacterium tuberculosis, Chlamydia pneumoniae.