Etiology of Suspected Pneumonia in Adults Admitted to a High-Dependency Unit in Blantyre, Malawi

Hartung, Thomas K.; Chimbayo, D; Oosterhout, Joep J. G. van; Chikaonda, Tarsizio; Doornum, G. J. J. Van; Claas, Eric C. J.; Melchers, Willem J. G.; Molyneux, Malcolm E.; Zijlstra, E.E.

doi:10.4269/ajtmh.2011.10-0640

Cited by 33 publications

(50 citation statements)

References 32 publications

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“…As expected, pneumococcus was the most common bacterial cause of serious ARI in this population, and was particularly prevalent among HIV-infected persons [2], [25], [32], [33], [34], [35], [36]. There was more than a 5-fold increase in the frequency of positive results for pneumococcus when incorporating the urine antigen test, supporting previous evidence that most pneumococcal pneumonia is non-bacteremic [25], [37].…”

Section: Discussionsupporting

confidence: 86%

Etiology and Incidence of Viral and Bacterial Acute Respiratory Illness among Older Children and Adults in Rural Western Kenya, 2007–2010

et al. 2012

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BackgroundFew comprehensive data exist on disease incidence for specific etiologies of acute respiratory illness (ARI) in older children and adults in Africa.Methodology/Principal FindingsFrom March 1, 2007, to February 28, 2010, among a surveillance population of 21,420 persons >5 years old in rural western Kenya, we collected blood for culture and malaria smears, nasopharyngeal and oropharyngeal swabs for quantitative real-time PCR for ten viruses and three atypical bacteria, and urine for pneumococcal antigen testing on outpatients and inpatients meeting a ARI case definition (cough or difficulty breathing or chest pain and temperature >38.0°C or oxygen saturation <90% or hospitalization). We also collected swabs from asymptomatic controls, from which we calculated pathogen-attributable fractions, adjusting for age, season, and HIV-status, in logistic regression. We calculated incidence by pathogen, adjusting for health-seeking for ARI and pathogen-attributable fractions. Among 3,406 ARI patients >5 years old (adjusted annual incidence 12.0 per 100 person-years), influenza A virus was the most common virus (22% overall; 11% inpatients, 27% outpatients) and Streptococcus pneumoniae was the most common bacteria (16% overall; 23% inpatients, 14% outpatients), yielding annual incidences of 2.6 and 1.7 episodes per 100 person-years, respectively. Influenza A virus, influenza B virus, respiratory syncytial virus (RSV) and human metapneumovirus were more prevalent in swabs among cases (22%, 6%, 8% and 5%, respectively) than controls. Adenovirus, parainfluenza viruses, rhinovirus/enterovirus, parechovirus, and Mycoplasma pneumoniae were not more prevalent among cases than controls. Pneumococcus and non-typhi Salmonella were more prevalent among HIV-infected adults, but prevalence of viruses was similar among HIV-infected and HIV-negative individuals. ARI incidence was highest during peak malaria season.Conclusions/SignficanceVaccination against influenza and pneumococcus (by potential herd immunity from childhood vaccination or of HIV-infected adults) might prevent much of the substantial ARI incidence among persons >5 years old in similar rural African settings.

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Section: Discussionsupporting

confidence: 86%

Etiology and Incidence of Viral and Bacterial Acute Respiratory Illness among Older Children and Adults in Rural Western Kenya, 2007–2010

et al. 2012

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“…Indeed, the P. jirovecii fungus is difficult to grow in culture, and the sensitivity of direct microscopic examination is low (26,27,(33)(34)(35). PCR has greatly increased the sensitivity of detection of P. jirovecii DNA.…”

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confidence: 99%

“…This colonization of nonimmunocompromised patients has cast doubt on its importance in sudden infant death syndrome, chronic obstructive pulmonary disease, cystic fibrosis, and other pulmonary syndromes (12,15,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). Although the clinical conditions and diseases for which P. jirovecii is responsible are unclear, the rate of colonization among individuals is underestimated (29).…”

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Detection of Pneumocystis jirovecii by Quantitative PCR To Differentiate Colonization and Pneumonia in Immunocompromised HIV-Positive and HIV-Negative Patients

et al. 2016

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dPneumocystis jirovecii pneumonia (PCP) is an acute and life-threatening lung disease caused by the fungus Pneumocystis jirovecii. The presentation of PCP in HIV-positive patients is well-known and consists of a triad of dyspnea, fever, and cough, whereas the presentation of PCP in HIV-negative patients is atypical and consists of a sudden outbreak, O 2 desaturation, and a rapid lethal outcome without therapy. Despite the availability of direct and indirect identification methods, the diagnosis of PCP remains difficult. The cycle threshold (C T ) values obtained by quantitative PCR (qPCR) allow estimation of the fungal burden. The more elevated that the fungal burden is, the higher the probability that the diagnosis is pneumonia. The purposes of the present study were to evaluate the C T values to differentiate colonization and pneumonia in a population of immunocompromised patients overall and patients stratified on the basis of their HIV infection status. Testing of bronchoalveolar lavage (BAL) fluid samples from the whole population of qPCR-positive patients showed a mean C T value for patients with PCP of 28 (95% confidence interval [CI], 26 to 30) and a mean C T value for colonized patients of 35 (95% CI, 34 to 36) (P < 10 ؊3 ). For the subgroup of HIV-positive patients, we demonstrated that a C T value below 27 excluded colonization and a C T value above 30 excluded PCP with a specificity of 100% and a sensitivity of 80%, respectively. In the subgroup of HIV-negative patients, we demonstrated that a C T value below 31 excluded colonization and a C T value above 35 excluded PCP with a specificity of 80% and a sensitivity of 80%, respectively. Thus, qPCR of BAL fluid samples is an important tool for the differentiation of colonization and pneumonia in P. jirovecii-infected immunocompromised patients and patients stratified on the basis of HIV infection status with different C T values.

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“…These marked differences in mortality burden may, in large part, reflect differences in population age distributions, but cause‐specific, age‐standardized mortality data are lacking. Amongst CAP cohorts from Africa, however, the typical trend of increasing mortality rates with advancing age seen in high‐income settings is not consistently found …”

Section: Pneumonia Epidemiology: a Global Perspectivementioning

confidence: 99%

Pneumonia in the developing world: Characteristic features and approach to management

Aston

2017

Respirology

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Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality in adults worldwide, but its epidemiology varies markedly by region. Whilst in high-income countries, the predominant burden of CAP is in the elderly and those with chronic cardiovascular and pulmonary co-morbidity, CAP patients in low-income settings are often of working age and, in sub-Saharan Africa, frequently HIV-positive. Although region-specific aetiological data are limited, they are sufficient to highlight major trends: in high-burden settings, tuberculosis (TB) is a common cause of acute CAP; Gram-negative pathogens such as Klebsiella pneumoniae are regionally important; and HIV-associated opportunistic infections are common but difficult to diagnose. These differences in epidemiology and aetiological profile suggest that modified approaches to diagnosis, severity assessment and empirical antimicrobial therapy of CAP are necessary, but tailored individualized management approaches are constrained by limitations in the availability of radiological and laboratory diagnostic services, as well as medical expertise. The widespread introduction of the Xpert MTB/RIF platform represents a major advance for TB diagnosis, but innovations in rapid diagnostics for other opportunistic pathogens are urgently needed. Severity assessment tools (e.g. CURB65) that are used to guide early management decisions in CAP have not been widely validated in low-income settings and locally adapted tools are required. The optimal approach to initial antimicrobial therapy choices such as the need to provide early empirical cover for atypical bacteria and TB remain poorly defined. Improvements in supportive care such as correcting hypoxaemia and intravenous fluid management represent opportunities for substantial reductions in mortality.

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Etiology of Suspected Pneumonia in Adults Admitted to a High-Dependency Unit in Blantyre, Malawi

Cited by 33 publications

References 32 publications

Etiology and Incidence of Viral and Bacterial Acute Respiratory Illness among Older Children and Adults in Rural Western Kenya, 2007–2010

Etiology and Incidence of Viral and Bacterial Acute Respiratory Illness among Older Children and Adults in Rural Western Kenya, 2007–2010

Detection of Pneumocystis jirovecii by Quantitative PCR To Differentiate Colonization and Pneumonia in Immunocompromised HIV-Positive and HIV-Negative Patients

Pneumonia in the developing world: Characteristic features and approach to management

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