Mamadou Sylla - Academia.edu (original) (raw)

Papers by Mamadou Sylla

HAL (Le Centre pour la Communication Scientifique Directe), 2012

Bulletin of Applied Economics, 2020

The objectives of this article is to target poverty using Dominance-based Rough Set Approach (DRS... more The objectives of this article is to target poverty using Dominance-based Rough Set Approach (DRSA) to help the United Nation’s Countries develop objectives for sustainable development. There are 12 variables divided into 2 perspectives. The first is an economical and technological perspective composed of 6 variables. The second is a sociological and political perspective composed of 6 variables. The methodology proposed classifies all the United Nation’s countries according to three different categories: [A] Developed countries; [B] Emerging economies that need support to acquire category A status; [C] Under Developed countries ranked the lowest and needing special support with regard to the criterion or criteria considered. Using this classification, DRSA provides decision rules to explain the classification and indicating precisely what are the conditions to be part of a higher category. Also, the results indicate what are the conditions to be part of the Under Developed countrie...

We study theoretically the optical properties (, , ) of a series of aromatic anions of the S-,... more We study theoretically the optical properties (, , ) of a series of aromatic anions of the S-, , and substituent groups, with n = 1, 2, 3 benzene rings, by using PM3 parametrization, Ab Initio at Hartree-Fock HF, M¢ller-Plesset MP2 and MP4 levels, and DFT methods at B3LYP level with the 6-31+G(d,p) and 6-311++G(3d,3p) basis sets. The dynamic properties where also evaluated with the Time Dependent Hartree-Fock (TDHF). Coupled Clusters CC methods were used for the benzene-thiolate anion properties only. Additionally, the nonlinear properties at PM3 level of some organometallic thiolates complexes: , where M = Zn, Cd,Hg, Pb and m = 3, 4, were also studied. On the other hand, we determined using the hyper Rayleigh-Scattering HRS experimental technique of some new synthesized chiral carboxylates salts using methanol as solvent and we also measured a series of bases of nucleic acid such as uracil, thymine, adenine, cytosine and 5-fluorouracil compounds in water solutions. Also, was stu...

On presente des resultats theoriques et experimentaux relatifs a l'etude de l'absorption ... more On presente des resultats theoriques et experimentaux relatifs a l'etude de l'absorption non lineaire et du melange 4-onde degenere en regime picoseconde dans les oxydes de bismuth silicium (b. S. O. ) et germanium (b. G. O. ). Les mesures sont faites sans champ electrique exterieur applique sur les cristaux et le modele developpe est base sur le formalisme des susceptibilites non lineaire d'ordre trois. En raison de l'importance de l'activite optique des composes etudies a la longueur d'onde du laser utilise (532 nm), les experiences ont ete effectuees en polarisations circulaires. Les rendements du melange quatre ondes des differents cristaux sont compares a ceux du disulfure de carbone dans les memes conditions d'experiences et les valeurs des coefficients du tenseur de susceptibilites non lineaire du troisieme ordre sont deduites

Pediatric Infectious Disease Journal, 2021

Supplemental Digital Content is available in the text.

Transboundary and Emerging Diseases, 2020

Since November 2018, several countries in West and Central Africa have reported mortalities in do... more Since November 2018, several countries in West and Central Africa have reported mortalities in donkeys and horses. Specifically, more than 66,000 horses and donkeys have succumbed to disease

Applied Economics and Finance, 2020

The unprecedented subprime crisis, the deregulation of the market, bank credit and payment mechan... more The unprecedented subprime crisis, the deregulation of the market, bank credit and payment mechanisms have facilitated the spread of the risk to the whole of economy. This study examines the issue of the processes set up to save the management of the global banking system. To achieve our goal, we conducted a survey of the various techniques used by banks to prevent global financial crises. At the end of our study, we found that the banks while opting for different policies play the same role and are increasingly hard to avoid risk.

International Journal of Human Resource Studies, 2019

The implementation of One Capp software within the Middle Office has a very strong impact on the ... more The implementation of One Capp software within the Middle Office has a very strong impact on the Re-Invoicing Servicing service; the importance of demonstrating the impact of ICT within an organization so that all banks are aware of it and can judge the impact of these tools within the various services. Hence, the contribution to a better understanding, by the employees, of the different techniques to obtain a better productivity within the firm concerned. Thus, the company is used as one of the many references in the field of new technologies.

Clinical Infectious Diseases, 2019

See the Editorial commentary by Todd Florin on pages 1058-9.) Background. In 2015, pneumonia rema... more See the Editorial commentary by Todd Florin on pages 1058-9.) Background. In 2015, pneumonia remained the leading cause of mortality in children aged 1-59 months. Methods. Data from 1802 human immunodeficiency virus (HIV)-negative children aged 1-59 months enrolled in the Pneumonia Etiology Research for Child Health (PERCH) study with severe or very severe pneumonia during 2011-2014 were used to build a parsimonious multivariable model predicting mortality using backwards stepwise logistic regression. The PERCH severity score, derived from model coefficients, was validated on a second, temporally discrete dataset of a further 1819 cases and compared to other available scores using the C statistic. Results. Predictors of mortality, across 7 low-and middle-income countries, were age <1 year, female sex, ≥3 days of illness prior to presentation to hospital, low weight for height, unresponsiveness, deep breathing, hypoxemia, grunting, and the absence of cough. The model discriminated well between those who died and those who survived (C statistic = 0.84), but the predictive capacity of the PERCH 5-stratum score derived from the coefficients was moderate (C statistic = 0.76). The performance of the Respiratory Index of Severity in Children score was similar (C statistic = 0.76). The number of World Health Organization (WHO) danger signs demonstrated the highest discrimination (C statistic = 0.82; 1.5% died if no danger signs, 10% if 1 danger sign, and 33% if ≥2 danger signs). Conclusions. The PERCH severity score could be used to interpret geographic variations in pneumonia mortality and etiology. The number of WHO danger signs on presentation to hospital could be the most useful of the currently available tools to aid clinical management of pneumonia.

The American journal of tropical medicine and hygiene, Jan 26, 2017

Nontyphoidal Salmonella (NTS) are the leading cause of foodborne infections worldwide and a major... more Nontyphoidal Salmonella (NTS) are the leading cause of foodborne infections worldwide and a major cause of bloodstream infections in infants and HIV-infected adults in sub-Saharan Africa (SSA). Salmonella Typhimurium (serogroup B) and Salmonella Enteritidis (serogroup D) are the most common serovars in this region. However, data describing rarer invasive NTS serovars, particularly those belonging to serogroups C1 and C2, circulating in SSA are lacking. We previously conducted systematic blood culture surveillance on pediatric patients in Bamako, Mali, from 2002 to 2014, and the results showed that serovars Typhimurium and Enteritidis accounted for 32% and 36% of isolates, respectively. Here, we present data on 27 Salmonella serogroup C1 strains that were isolated during this previous study. The strains were typed by serum agglutination and multilocus sequence typing (MLST). Sixteen strains were Salmonella Paratyphi C, four were Salmonella Colindale, and two were Salmonella Virchow. ...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrol... more Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Lack of a gold standard for identifying bacterial and viral etiologies of pneumonia has limited e... more Lack of a gold standard for identifying bacterial and viral etiologies of pneumonia has limited evaluation of C-reactive protein (CRP) for identifying bacterial pneumonia. We evaluated the sensitivity and specificity of CRP for identifying bacterial vs respiratory syncytial virus (RSV) pneumonia in the Pneumonia Etiology Research for Child Health (PERCH) multicenter case-control study. We measured serum CRP levels in cases with World Health Organization-defined severe or very severe pneumonia and a subset of community controls. We evaluated the sensitivity and specificity of elevated CRP for "confirmed" bacterial pneumonia (positive blood culture or positive lung aspirate or pleural fluid culture or polymerase chain reaction [PCR]) compared to "RSV pneumonia" (nasopharyngeal/oropharyngeal or induced sputum PCR-positive without confirmed/suspected bacterial pneumonia). Receiver operating characteristic (ROC) curves were constructed to assess the performance of ele...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Chest radiographs (CXRs) are frequently used to assess pneumonia cases. Variations in CXR appeara... more Chest radiographs (CXRs) are frequently used to assess pneumonia cases. Variations in CXR appearances between epidemiological settings and their correlation with clinical signs are not well documented. The Pneumonia Etiology Research for Child Health project enrolled 4232 cases of hospitalized World Health Organization (WHO)-defined severe and very severe pneumonia from 9 sites in 7 countries (Bangladesh, the Gambia, Kenya, Mali, South Africa, Thailand, and Zambia). At admission, each case underwent a standardized assessment of clinical signs and pneumonia risk factors by trained health personnel, and a CXR was taken that was interpreted using the standardized WHO methodology. CXRs were categorized as abnormal (consolidation and/or other infiltrate), normal, or uninterpretable. CXRs were interpretable in 3587 (85%) cases, of which 1935 (54%) were abnormal (site range, 35%-64%). Cases with abnormal CXRs were more likely than those with normal CXRs to have hypoxemia (45% vs 26%), crac...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Previous studies suggested an association between upper airway pneumococcal colonization density ... more Previous studies suggested an association between upper airway pneumococcal colonization density and pneumococcal pneumonia, but data in children are limited. Using data from the Pneumonia Etiology Research for Child Health (PERCH) study, we assessed this potential association. PERCH is a case-control study in 7 countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. Cases were children aged 1-59 months hospitalized with World Health Organization-defined severe or very severe pneumonia. Controls were randomly selected from the community. Microbiologically confirmed pneumococcal pneumonia (MCPP) was confirmed by detection of pneumococcus in a relevant normally sterile body fluid. Colonization density was calculated with quantitative polymerase chain reaction analysis of nasopharyngeal/oropharyngeal specimens. Median colonization density among 56 cases with MCPP (MCPP cases; 17.28 × 106 copies/mL) exceeded that of cases without MCPP (non-MCPP cases; 0.75 × ...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

The etiologic inference of identifying a pathogen in the upper respiratory tract (URT) of childre... more The etiologic inference of identifying a pathogen in the upper respiratory tract (URT) of children with pneumonia is unclear. To determine if viral load could provide evidence of causality of pneumonia, we compared viral load in the URT of children with World Health Organization-defined severe and very severe pneumonia and age-matched community controls. In the 9 developing country sites, nasopharyngeal/oropharyngeal swabs from children with and without pneumonia were tested using quantitative real-time polymerase chain reaction for 17 viruses. The association of viral load with case status was evaluated using logistic regression. Receiver operating characteristic (ROC) curves were constructed to determine optimal discriminatory viral load cutoffs. Viral load density distributions were plotted. The mean viral load was higher in cases than controls for 7 viruses. However, there was substantial overlap in viral load distribution of cases and controls for all viruses. ROC curves to det...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Detection of pneumococcus by lytA polymerase chain reaction (PCR) in blood had poor diagnostic ac... more Detection of pneumococcus by lytA polymerase chain reaction (PCR) in blood had poor diagnostic accuracy for diagnosing pneumococcal pneumonia in children in 9 African and Asian sites. We assessed the value of blood lytA quantification in diagnosing pneumococcal pneumonia. The Pneumonia Etiology Research for Child Health (PERCH) case-control study tested whole blood by PCR for pneumococcus in children aged 1-59 months hospitalized with signs of pneumonia and in age-frequency matched community controls. The distribution of load among PCR-positive participants was compared between microbiologically confirmed pneumococcal pneumonia (MCPP) cases, cases confirmed for nonpneumococcal pathogens, nonconfirmed cases, and controls. Receiver operating characteristic analyses determined the "optimal threshold" that distinguished MCPP cases from controls. Load was available for 290 of 291 cases with pneumococcal PCR detected in blood and 273 of 273 controls. Load was higher in MCPP case...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Induced sputum (IS) may provide diagnostic information about the etiology of pneumonia. The safet... more Induced sputum (IS) may provide diagnostic information about the etiology of pneumonia. The safety of this procedure across a heterogeneous population with severe pneumonia in low- and middle-income countries has not been described. IS specimens were obtained as part a 7-country study of the etiology of severe and very severe pneumonia in hospitalized children <5 years of age. Rigorous clinical monitoring was done before, during, and after the procedure to record oxygen requirement, oxygen saturation, respiratory rate, consciousness level, and other evidence of clinical deterioration. Criteria for IS contraindications were predefined and serious adverse events (SAEs) were reported to ethics committees and a central safety monitor. A total of 4653 IS procedures were done among 3802 children. Thirteen SAEs were reported in relation to collection of IS, or 0.34% of children with at least 1 IS specimen collected (95% confidence interval, 0.15%-0.53%). A drop in oxygen saturation that...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Sputum examination can be useful in diagnosing the cause of pneumonia in adults but is less well ... more Sputum examination can be useful in diagnosing the cause of pneumonia in adults but is less well established in children. We sought to assess the diagnostic utility of polymerase chain reaction (PCR) for detection of respiratory viruses and bacteria in induced sputum (IS) specimens from children hospitalized with severe or very severe pneumonia. Among children aged 1-59 months, we compared organism detection by multiplex PCR in IS and nasopharyngeal/oropharyngeal (NP/OP) specimens. To assess whether organism presence or density in IS specimens was associated with chest radiographic evidence of pneumonia (radiographic pneumonia), we compared prevalence and density in IS specimens from children with radiographic pneumonia and children with suspected pneumonia but without chest radiographic changes or clinical or laboratory findings suggestive of pneumonia (nonpneumonia group). Among 4232 cases with World Health Organization-defined severe or very severe pneumonia, we identified 1935 (...

HAL (Le Centre pour la Communication Scientifique Directe), 2012

Bulletin of Applied Economics, 2020

The objectives of this article is to target poverty using Dominance-based Rough Set Approach (DRS... more The objectives of this article is to target poverty using Dominance-based Rough Set Approach (DRSA) to help the United Nation’s Countries develop objectives for sustainable development. There are 12 variables divided into 2 perspectives. The first is an economical and technological perspective composed of 6 variables. The second is a sociological and political perspective composed of 6 variables. The methodology proposed classifies all the United Nation’s countries according to three different categories: [A] Developed countries; [B] Emerging economies that need support to acquire category A status; [C] Under Developed countries ranked the lowest and needing special support with regard to the criterion or criteria considered. Using this classification, DRSA provides decision rules to explain the classification and indicating precisely what are the conditions to be part of a higher category. Also, the results indicate what are the conditions to be part of the Under Developed countrie...

We study theoretically the optical properties (, , ) of a series of aromatic anions of the S-,... more We study theoretically the optical properties (, , ) of a series of aromatic anions of the S-, , and substituent groups, with n = 1, 2, 3 benzene rings, by using PM3 parametrization, Ab Initio at Hartree-Fock HF, M¢ller-Plesset MP2 and MP4 levels, and DFT methods at B3LYP level with the 6-31+G(d,p) and 6-311++G(3d,3p) basis sets. The dynamic properties where also evaluated with the Time Dependent Hartree-Fock (TDHF). Coupled Clusters CC methods were used for the benzene-thiolate anion properties only. Additionally, the nonlinear properties at PM3 level of some organometallic thiolates complexes: , where M = Zn, Cd,Hg, Pb and m = 3, 4, were also studied. On the other hand, we determined using the hyper Rayleigh-Scattering HRS experimental technique of some new synthesized chiral carboxylates salts using methanol as solvent and we also measured a series of bases of nucleic acid such as uracil, thymine, adenine, cytosine and 5-fluorouracil compounds in water solutions. Also, was stu...

On presente des resultats theoriques et experimentaux relatifs a l'etude de l'absorption ... more On presente des resultats theoriques et experimentaux relatifs a l'etude de l'absorption non lineaire et du melange 4-onde degenere en regime picoseconde dans les oxydes de bismuth silicium (b. S. O. ) et germanium (b. G. O. ). Les mesures sont faites sans champ electrique exterieur applique sur les cristaux et le modele developpe est base sur le formalisme des susceptibilites non lineaire d'ordre trois. En raison de l'importance de l'activite optique des composes etudies a la longueur d'onde du laser utilise (532 nm), les experiences ont ete effectuees en polarisations circulaires. Les rendements du melange quatre ondes des differents cristaux sont compares a ceux du disulfure de carbone dans les memes conditions d'experiences et les valeurs des coefficients du tenseur de susceptibilites non lineaire du troisieme ordre sont deduites

Pediatric Infectious Disease Journal, 2021

Supplemental Digital Content is available in the text.

Transboundary and Emerging Diseases, 2020

Since November 2018, several countries in West and Central Africa have reported mortalities in do... more Since November 2018, several countries in West and Central Africa have reported mortalities in donkeys and horses. Specifically, more than 66,000 horses and donkeys have succumbed to disease

Applied Economics and Finance, 2020

The unprecedented subprime crisis, the deregulation of the market, bank credit and payment mechan... more The unprecedented subprime crisis, the deregulation of the market, bank credit and payment mechanisms have facilitated the spread of the risk to the whole of economy. This study examines the issue of the processes set up to save the management of the global banking system. To achieve our goal, we conducted a survey of the various techniques used by banks to prevent global financial crises. At the end of our study, we found that the banks while opting for different policies play the same role and are increasingly hard to avoid risk.

International Journal of Human Resource Studies, 2019

The implementation of One Capp software within the Middle Office has a very strong impact on the ... more The implementation of One Capp software within the Middle Office has a very strong impact on the Re-Invoicing Servicing service; the importance of demonstrating the impact of ICT within an organization so that all banks are aware of it and can judge the impact of these tools within the various services. Hence, the contribution to a better understanding, by the employees, of the different techniques to obtain a better productivity within the firm concerned. Thus, the company is used as one of the many references in the field of new technologies.

Clinical Infectious Diseases, 2019

See the Editorial commentary by Todd Florin on pages 1058-9.) Background. In 2015, pneumonia rema... more See the Editorial commentary by Todd Florin on pages 1058-9.) Background. In 2015, pneumonia remained the leading cause of mortality in children aged 1-59 months. Methods. Data from 1802 human immunodeficiency virus (HIV)-negative children aged 1-59 months enrolled in the Pneumonia Etiology Research for Child Health (PERCH) study with severe or very severe pneumonia during 2011-2014 were used to build a parsimonious multivariable model predicting mortality using backwards stepwise logistic regression. The PERCH severity score, derived from model coefficients, was validated on a second, temporally discrete dataset of a further 1819 cases and compared to other available scores using the C statistic. Results. Predictors of mortality, across 7 low-and middle-income countries, were age <1 year, female sex, ≥3 days of illness prior to presentation to hospital, low weight for height, unresponsiveness, deep breathing, hypoxemia, grunting, and the absence of cough. The model discriminated well between those who died and those who survived (C statistic = 0.84), but the predictive capacity of the PERCH 5-stratum score derived from the coefficients was moderate (C statistic = 0.76). The performance of the Respiratory Index of Severity in Children score was similar (C statistic = 0.76). The number of World Health Organization (WHO) danger signs demonstrated the highest discrimination (C statistic = 0.82; 1.5% died if no danger signs, 10% if 1 danger sign, and 33% if ≥2 danger signs). Conclusions. The PERCH severity score could be used to interpret geographic variations in pneumonia mortality and etiology. The number of WHO danger signs on presentation to hospital could be the most useful of the currently available tools to aid clinical management of pneumonia.

The American journal of tropical medicine and hygiene, Jan 26, 2017

Nontyphoidal Salmonella (NTS) are the leading cause of foodborne infections worldwide and a major... more Nontyphoidal Salmonella (NTS) are the leading cause of foodborne infections worldwide and a major cause of bloodstream infections in infants and HIV-infected adults in sub-Saharan Africa (SSA). Salmonella Typhimurium (serogroup B) and Salmonella Enteritidis (serogroup D) are the most common serovars in this region. However, data describing rarer invasive NTS serovars, particularly those belonging to serogroups C1 and C2, circulating in SSA are lacking. We previously conducted systematic blood culture surveillance on pediatric patients in Bamako, Mali, from 2002 to 2014, and the results showed that serovars Typhimurium and Enteritidis accounted for 32% and 36% of isolates, respectively. Here, we present data on 27 Salmonella serogroup C1 strains that were isolated during this previous study. The strains were typed by serum agglutination and multilocus sequence typing (MLST). Sixteen strains were Salmonella Paratyphi C, four were Salmonella Colindale, and two were Salmonella Virchow. ...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrol... more Many pneumonia etiology case-control studies exclude controls with respiratory illness from enrollment or analyses. Herein we argue that selecting controls regardless of respiratory symptoms provides the least biased estimates of pneumonia etiology. We review 3 reasons investigators may choose to exclude controls with respiratory symptoms in light of epidemiologic principles of control selection and present data from the Pneumonia Etiology Research for Child Health (PERCH) study where relevant to assess their validity. We conclude that exclusion of controls with respiratory symptoms will result in biased estimates of etiology. Randomly selected community controls, with or without respiratory symptoms, as long as they do not meet the criteria for case-defining pneumonia, are most representative of the general population from which cases arose and the least subject to selection bias.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Lack of a gold standard for identifying bacterial and viral etiologies of pneumonia has limited e... more Lack of a gold standard for identifying bacterial and viral etiologies of pneumonia has limited evaluation of C-reactive protein (CRP) for identifying bacterial pneumonia. We evaluated the sensitivity and specificity of CRP for identifying bacterial vs respiratory syncytial virus (RSV) pneumonia in the Pneumonia Etiology Research for Child Health (PERCH) multicenter case-control study. We measured serum CRP levels in cases with World Health Organization-defined severe or very severe pneumonia and a subset of community controls. We evaluated the sensitivity and specificity of elevated CRP for "confirmed" bacterial pneumonia (positive blood culture or positive lung aspirate or pleural fluid culture or polymerase chain reaction [PCR]) compared to "RSV pneumonia" (nasopharyngeal/oropharyngeal or induced sputum PCR-positive without confirmed/suspected bacterial pneumonia). Receiver operating characteristic (ROC) curves were constructed to assess the performance of ele...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Chest radiographs (CXRs) are frequently used to assess pneumonia cases. Variations in CXR appeara... more Chest radiographs (CXRs) are frequently used to assess pneumonia cases. Variations in CXR appearances between epidemiological settings and their correlation with clinical signs are not well documented. The Pneumonia Etiology Research for Child Health project enrolled 4232 cases of hospitalized World Health Organization (WHO)-defined severe and very severe pneumonia from 9 sites in 7 countries (Bangladesh, the Gambia, Kenya, Mali, South Africa, Thailand, and Zambia). At admission, each case underwent a standardized assessment of clinical signs and pneumonia risk factors by trained health personnel, and a CXR was taken that was interpreted using the standardized WHO methodology. CXRs were categorized as abnormal (consolidation and/or other infiltrate), normal, or uninterpretable. CXRs were interpretable in 3587 (85%) cases, of which 1935 (54%) were abnormal (site range, 35%-64%). Cases with abnormal CXRs were more likely than those with normal CXRs to have hypoxemia (45% vs 26%), crac...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Previous studies suggested an association between upper airway pneumococcal colonization density ... more Previous studies suggested an association between upper airway pneumococcal colonization density and pneumococcal pneumonia, but data in children are limited. Using data from the Pneumonia Etiology Research for Child Health (PERCH) study, we assessed this potential association. PERCH is a case-control study in 7 countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. Cases were children aged 1-59 months hospitalized with World Health Organization-defined severe or very severe pneumonia. Controls were randomly selected from the community. Microbiologically confirmed pneumococcal pneumonia (MCPP) was confirmed by detection of pneumococcus in a relevant normally sterile body fluid. Colonization density was calculated with quantitative polymerase chain reaction analysis of nasopharyngeal/oropharyngeal specimens. Median colonization density among 56 cases with MCPP (MCPP cases; 17.28 × 106 copies/mL) exceeded that of cases without MCPP (non-MCPP cases; 0.75 × ...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

The etiologic inference of identifying a pathogen in the upper respiratory tract (URT) of childre... more The etiologic inference of identifying a pathogen in the upper respiratory tract (URT) of children with pneumonia is unclear. To determine if viral load could provide evidence of causality of pneumonia, we compared viral load in the URT of children with World Health Organization-defined severe and very severe pneumonia and age-matched community controls. In the 9 developing country sites, nasopharyngeal/oropharyngeal swabs from children with and without pneumonia were tested using quantitative real-time polymerase chain reaction for 17 viruses. The association of viral load with case status was evaluated using logistic regression. Receiver operating characteristic (ROC) curves were constructed to determine optimal discriminatory viral load cutoffs. Viral load density distributions were plotted. The mean viral load was higher in cases than controls for 7 viruses. However, there was substantial overlap in viral load distribution of cases and controls for all viruses. ROC curves to det...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Detection of pneumococcus by lytA polymerase chain reaction (PCR) in blood had poor diagnostic ac... more Detection of pneumococcus by lytA polymerase chain reaction (PCR) in blood had poor diagnostic accuracy for diagnosing pneumococcal pneumonia in children in 9 African and Asian sites. We assessed the value of blood lytA quantification in diagnosing pneumococcal pneumonia. The Pneumonia Etiology Research for Child Health (PERCH) case-control study tested whole blood by PCR for pneumococcus in children aged 1-59 months hospitalized with signs of pneumonia and in age-frequency matched community controls. The distribution of load among PCR-positive participants was compared between microbiologically confirmed pneumococcal pneumonia (MCPP) cases, cases confirmed for nonpneumococcal pathogens, nonconfirmed cases, and controls. Receiver operating characteristic analyses determined the "optimal threshold" that distinguished MCPP cases from controls. Load was available for 290 of 291 cases with pneumococcal PCR detected in blood and 273 of 273 controls. Load was higher in MCPP case...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Induced sputum (IS) may provide diagnostic information about the etiology of pneumonia. The safet... more Induced sputum (IS) may provide diagnostic information about the etiology of pneumonia. The safety of this procedure across a heterogeneous population with severe pneumonia in low- and middle-income countries has not been described. IS specimens were obtained as part a 7-country study of the etiology of severe and very severe pneumonia in hospitalized children <5 years of age. Rigorous clinical monitoring was done before, during, and after the procedure to record oxygen requirement, oxygen saturation, respiratory rate, consciousness level, and other evidence of clinical deterioration. Criteria for IS contraindications were predefined and serious adverse events (SAEs) were reported to ethics committees and a central safety monitor. A total of 4653 IS procedures were done among 3802 children. Thirteen SAEs were reported in relation to collection of IS, or 0.34% of children with at least 1 IS specimen collected (95% confidence interval, 0.15%-0.53%). A drop in oxygen saturation that...

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, Jan 15, 2017

Sputum examination can be useful in diagnosing the cause of pneumonia in adults but is less well ... more Sputum examination can be useful in diagnosing the cause of pneumonia in adults but is less well established in children. We sought to assess the diagnostic utility of polymerase chain reaction (PCR) for detection of respiratory viruses and bacteria in induced sputum (IS) specimens from children hospitalized with severe or very severe pneumonia. Among children aged 1-59 months, we compared organism detection by multiplex PCR in IS and nasopharyngeal/oropharyngeal (NP/OP) specimens. To assess whether organism presence or density in IS specimens was associated with chest radiographic evidence of pneumonia (radiographic pneumonia), we compared prevalence and density in IS specimens from children with radiographic pneumonia and children with suspected pneumonia but without chest radiographic changes or clinical or laboratory findings suggestive of pneumonia (nonpneumonia group). Among 4232 cases with World Health Organization-defined severe or very severe pneumonia, we identified 1935 (...