Epidemiology and microbiological investigations of community-acquired pneumonia in children admitted at the emergency department of a university hospital

BackgroundThe management of children with community-acquired pneumonia (CAP) is largely influenced by the development of new molecular diagnostic tests that allow the simultaneous detection of a wide range of pathogens.ObjectivesEvaluation of a diagnostic approach including multiplex PCR assays for revisiting the epidemiology and etiology of CAP in children at hospital.Study designChildren of all ages consulting at the Emergency Department of the University hospital of Saint-Etienne, France, during the 2012–2013 winter period were included. In addition to bacterial cultures, the following pathogens were detected using biplex commercially-available rt-PCR tests: adenovirus, respiratory syncytial virus, human metapneumovirus, bocavirus, rhinovirus/enterovirus, coronavirus, influenza viruses A and B, parainfluenza viruses, Mycoplasma pneumoniae and Chlamydophila pneumonia.ResultsFrom 85 patients with CAP, at least one pathogen was identified in 81 cases (95.3%), including 4 bacterial exclusive infections (4.7%), 53 viral exclusive infections (62.4%) and 24 mixed infections (28.2%). Coinfection by at least two viruses was observed in 37 cases (43.5%). Mean age was higher in the case of documented bacterial infection (P < 0.05). In the subgroup of viral exclusive infection, the mean age of severe cases was 2.0 years vs 3.8 years in mild and moderate cases (P < 0.05).ConclusionsThese findings highlight the huge proportion of CAP of viral origin, the high number of co-infection by multiple viruses and the low number of bacterial CAP, notably in children under 5 years, and address the need to re-evaluate the indications of empiric antimicrobial treatment in this age group.     

Hyponatraemia in cases of children with pneumonia

Introduction

Hyponatraemia is the most common electrolyte imbalance seen in clinical practice, and a common laboratory finding in children with community-acquired pneumonia (CAP). This study aimed to identify the incidence of hyponatraemia in cases of CAP, to find predictive tools in order to classify the severity and outcome of CAP and to explore possible differences of clinical importance between the two sexes.

Material and methods

The medical files of 54 children (66.4% males), 4.67 ±2.88 years old, were retro-prospectively reviewed.

Results

35/54 (64.8%) children with pneumonia had normal values of sodium at admission, 18/54 (33.3%) had mild hyponatraemia and 1 child (1.9%) moderate hyponatraemia. Increased heart rhythm and tachypnoea at admission were correlated with lower values of sodium (z= −2.664, p = 0.007 and z = −1.705, p = 0.089 respectively). No differences were found between the two sexes concerning the characteristics of pneumonia or the range of sodium in serum at admission. A correlation was found between sodium admission values and: a) C-reactive protein (p = 0.000), and b) leukocyte count (p = 0.006). Sedimentation rate (p = 0.021) was also considered as a possible risk factor affecting the value of sodium at admission to hospital. Finally, a negative association was also observed between the degree of hyponatraemia and the duration of hospitalization (z = −3.398, p = 0.001).

Conclusions

Although studies in larger population groups are needed, in our study increased heart rhythm, tachypnoea, leucocyte count, C-reactive protein, and also erythrocyte sedimentation rate could be considered as possible risk factors influencing the degree of hyponatraemia, and thus the outcome of hospitalized children with CAP.     

小儿艾滋病合并肺炎诊治93例报告

目的　探讨小儿艾滋病与肺炎之间的发病关系及诊治措施。方法　回顾性分析了中非某地区 93例小儿艾滋病合并肺炎的综合治疗过程。结果　 93例中 ,治愈 81例 ,治愈率 87 1% ,死亡 12例 ,死亡率 12 9%。结论　合理应用普通药物治疗小儿艾滋病合并肺炎效果显著     

Immunohistochemical and in situ detection of cytomegalovirus in lung autopsies of children immunocompromised by secondary interstitial pneumonia

Secondary interstitial pneumonia (SIP), a disease affecting patients immunocompromised by primary underlying diseases during their treatment in hospital, is frequently associated with cytomegalovirus (CMV) infection, a potentially treatable condition. However, in many cases, no infectious agent can be determined, and this clinical disease rapidly progresses to death. Theoretically, SIP could be caused by CMV, which may be present in such small amounts or such configuration that routine histopathological analysis or viral culture techniques cannot detect the virus. To test the hypothesis that immunohistochemistry (IH) and in situ detection by hybridization (ISH) provides more accurate results than the mere histological demonstration of CMV inclusions, these methods were applied to 37 autopsied lung sections obtained from children immunocompromised by primary underlying diseases and who died of SIP. As a result, the cases were subdivided into three groups: (1) children with SIP CMV inclusions (Diffuse alveolar damage-DAD-related) (n = 7); (2) children with SIP without classical viral inclusions (CMV-DAD-related) (n = 3); (3) children with SIP exhibiting nuclear cytopathic effect (not CMV-NSIP-related) (n = 27). In the first group, all three techniques yielded clearly positive results, whereas IH and ISH indicated that three of the children of the second group had CMV-related DAD without histological demonstration of CMV inclusions. In the third group, there were no positive CMV signals. These data indicate that DAD-related CMV infection is an important cause of SIP and of death in children immunosuppressed by primary underlying diseases, and that IH and in situ detection were more sensitive than the histological demonstration of CMV inclusions. A direct involvement of CMV in SIP exhibiting DAD is likely, but not in the non-specific interstitial pneumonia (NSIP) pattern. We conclude that all children with primary underlying diseases should be investigated for CMV SIP using sensitive IH and in situ tests in conjunction with histological routine procedures.     

Correlates of diarrhoea among children below the age of 5 years in Sudan

Background

The Millennium Development Goals recognise child health and survival as an important socio-development issue.

Objectives

To determine the correlates of diarrhoea among children aged below 5 years in north Sudan.

Methods

We conducted secondary data analysis of the Sudan Multiple Cluster Indicators Survey II.

Results

Altogether, 23,295 children were included in the survey. Half (50.0%) of the children were males, and 22.5% of them were of age less than one year. Boys were 3% (p=0.044) more likely to have diarrhoea compared to girls. Compared with the oldest age group (48–59 months), children less than 6 months of age and those aged 36–47 months had 25% and 18% lower prevalence of diarrhoea, respectively, while children aged 6–24 months and those aged 24–35 months had 1.5 fold and 1.17 fold higher prevalence of diarrhoea. Children in urban areas were 6% more likely to have diarrhoea. Children from households with 1 or 2 people per room were 8% less likely to have diarrhoea compared to children from households with more than 3 people per room.

Conclusions

Diarrhoea was associated with child''s age, gender, and social status. Our findings provide a useful baseline for interventions and comparisons with future studies.     

支气管肺炎患儿机体免疫功能变化的分析

目的通过对支气管肺炎患儿T细胞亚群、血清免疫球蛋白、血清补体及细胞因子变化的分析,探讨小儿支气管肺炎机体免疫功能状态及免疫学发病机制,为临床了解病情、选择适当的治疗方案提供理论依据。方法支气管肺炎组65例,男39例,女26例,年龄2个月～13岁,平均年龄4.1岁。对照组20例,男12例,女8例,年龄1～12岁,平均年龄4.3岁。应用多色流式细胞术检测T细胞亚群(CD3+、CD3+CD4+Th、CD3+CD8+Ts、CD3+CD4+Th/CD3+CD8+Ts)、应用免疫散射比浊法检测血清免疫球蛋白(IgG、IgA、IgM)、血清补体(C3、C4)、应用ELISA法检测血清细胞因子(IFN-γ、IL-4)。结果支气管肺炎组T细胞亚群改变明显,CD3+、CD3+CD4+Th显著低于对照组,有统计学意义(P<0.01);CD3+CD8+Ts显著高于对照组,有统计学意义(P<0.01);CD3+CD4+Th/CD3+CD8+Ts比值降低,与对照组相比,有统计学意义(P<0.05)。支气管肺炎组血清IgA、IgG水平显著低于对照组,有统计学意义(P<0.01);支气管肺炎组血清补体C3低于对照组,有统计学意义(P<0.05)。支气管肺炎组血清细胞因子IFN-γ浓度及Th1/Th2比值高于对照组,有统计学意义(P<0.05)。结论支气管肺炎患儿存在细胞免疫和体液免疫功能紊乱,对支气管肺炎患儿检测免疫功能有助于判断病情、指导治疗。     

Clinical characteristics of hospitalized children with community-acquired pneumonia and respiratory infections: Using machine learning approaches to support pathogen prediction at admission

BackgroundAcute respiratory infections (ARIs) are common in children. We developed machine learning models to predict pediatric ARI pathogens at admission.MethodsWe included hospitalized children with respiratory infections between 2010 and 2018. Clinical features were collected within 24 h of admission to construct models. The outcome of interest was the prediction of 6 common respiratory pathogens, including adenovirus, influenza virus types A and B, parainfluenza virus (PIV), respiratory syncytial virus (RSV), and Mycoplasma pneumoniae (MP). Model performance was estimated using area under the receiver operating characteristic curve (AUROC). Feature importance was measured using Shapley Additive exPlanation (SHAP) values.ResultsA total of 12,694 admissions were included. Models trained with 9 features (age, event pattern, fever, C-reactive protein, white blood cell count, platelet count, lymphocyte ratio, peak temperature, peak heart rate) achieved the best performance (AUROC: MP 0.87, 95% CI 0.83–0.90; RSV 0.84, 95% CI 0.82–0.86; adenovirus 0.81, 95% CI 0.77–0.84; influenza A 0.77, 95% CI 0.73–0.80; influenza B 0.70, 95% CI 0.65–0.75; PIV 0.73, 95% CI 0.69–0.77). Age was the most important feature to predict MP, RSV and PIV infections. Event patterns were useful for influenza virus prediction, and C-reactive protein had the highest SHAP value for adenovirus infections.ConclusionWe demonstrate how artificial intelligence can assist clinicians identify potential pathogens associated with pediatric ARIs upon admission. Our models provide explainable results that could help optimize the use of diagnostic testing. Integrating our models into clinical workflows may lead to improved patient outcomes and reduce unnecessary medical costs.     

Viruses and bacteria in sputum samples of children with community-acquired pneumonia

Few comprehensive studies have searched for viruses and bacteria in children with community-acquired pneumonia (CAP). We identified 76 children hospitalized for pneumonia. Induced sputum samples were analysed for 18 viruses by antigen detection and PCR, and for six bacteria by culture and PCR. Viruses were found in 72% of samples, bacteria in 91%, and both in 66%. Rhinovirus (30%), human bocavirus (18%) and human metapneumovirus (14%) were the most commonly detected viruses. Two viruses were found in 22% of samples and three in 8%. The most common bacteria found were Streptococcus pneumoniae (50%), Haemophilus influenzae (38%), and Moraxella catarrhalis (28%). Rhinovirus–S. pneumoniae was the most commonly found combination of virus and bacterium (16%). All six children with treatment failure had both viruses and bacteria detected in the sputum. Otherwise, we found no special clinical characteristics in those with mixed viral–bacterial detections. With modern molecular diagnostic techniques, there are high rates of both viral and bacterial identification in childhood CAP. The clinical significance of mixed viral–bacterial infections remains unclear, although we found a potential association between them and treatment failure.     

Prevalence of B. pertussis infection in children with clinically suspected pertussis

BackgroundPertussis is an important cause of hospitalization in children. Limited data on pertussis have been reported from China. The aim of this study was to characterize clinically suspected pertussis attributable to Bordetella pertussis among children and determine factors associated with longer duration of hospital stay in B. pertussis infection.MethodsTwo hundred and seventeen consecutive children with clinically suspected pertussis were prospectively enrolled in the study between Jan 2016 through Aug 2017. Variables assessed included demographics, clinical symptoms and laboratory findings. Cox proportional hazards regression model were used to predict variables associated with longer duration of hospital stay.ResultsAmong the 217 patients with clinically suspected pertussis, B. pertussis was found in 106 (48.8%) patients. Of the 106 children with B. pertussis infection, 63 (59.4%) patients had coinfections with majority due to rhinovirus (HRV) (30.2%), Mycoplasma pneumoniae (29.2%) and human bocavirus (hBoV) (11.3%). Presence of coinfection [odds ratio (OR): 1.73, CI: 1.17–2.54], age ≤ 3 months (OR: 1.51, CI: 1.09 to 2.27), and WBC count ≥30 × 10⁹/L (OR: 1.66, CI: 1.07 to 2.84) were independently associated with a longer hospital stay.ConclusionsB. pertussis infection had a high coinfection rate with the majority of coinfections due to HRV, M. pneumoniae and hBoV. Presence of coinfection, Age ≤3 months and WBC count ≥30 × 10⁹/L were associated with a longer hospital stay. Children admitted with pertussis need close monitoring when they had evidence of coinfection, Age ≤3 months, WBC count ≥30 × 10⁹/L.     

Gram-negative bacterial pneumonia with secondary aspergillosis in an AIDS patient

Summary A 40-year-old, HIV-infected female patient received antibiotic treatment for a urinary tract infection. After the initial success of therapy and a symptom-free period, she developed pneumonia with septic shock and adult respiratory distress syndrome (ARDS). In spite of intensive care and respirator therapy with positive end-expiratory pressure (PEEP), she died of infectious toxic shock. Autopsy findings showed relapsing, gramnegative, bacterial pneumonia (morphologically compatible with Klebsiella pneumonia) and secondary, invasive aspergillosis. The pathogenesis and epidemiology of these unusual complications of AIDS are discussed.Abbreviations AIDS acquired immunodeficiency syndrome - ARDS adult respiratory distress syndrome - CDC Centers for Disease Control - HIV human immunodeficiency virus - PEEP positive end-expiratory pressure     

Development of an ELISA for detection of Sudan I in food samples using monoclonal antibody

A highly sensitive and specific indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) has been developed using a new monoclonal antibody for detecting the food colourant Sudan I. The half-maximum inhibition concentrations (IC₅₀) and the limit of detection (calculated as IC₂₀) of ELISA for Sudan I were 2 and 0.01 ng mL^?1, respectively. The study showed little cross-activity with Sudan I structural analogues (below 0.01%). The average recoveries in intra- and interassays for Sudan I from fortified fresh tomato and chilli samples by ELISA were in ranges of 82–94% and 79–91%, respectively. The coefficients of variation of intra- and interassays were 6–8% and 6–10%, respectively. The IC₅₀ was approximately 2.0 ng mL^?1 after the Sudan I-Kit had been kept for 180 days.     

Prevalence and correlates of multiple non-communicable diseases risk factors among male and female adults in Sudan: results of the first national STEPS survey in 2016

BackgroundNon-communicable diseases (NCDs) are on the rise in low- and middle-income countries. The aim of this study was to assess the prevalence and correlates of multiple NCD risk factors (inadequate fruit and vegetable intake, low physical activity, tobacco use, heavy alcohol use, diabetes, hypertension, raised total cholesterol and overweight/obesity) among adults in Sudan.MethodsWe conducted a cross-sectional study using nationally representative data. The analytic cohort included 7,722 participants who were between the ages of 18–69 years old individuals (median age=36 years) that took part in the “2016 Sudan STEPS survey.”ResultsIn all, 34.2% had 0–1 NCD risk factor, 33.5% 2 risk factors, and 32.4% 3 or more NCD risk factors. In adjusted ordinal logistic regression analysis, the odds of having a higher count of NCD risk factors increased from 2.04 to 3.52 from the age group of 35–49 years to age group of 50–69 years when compared to the younger people aged 18–34 years. Men had higher odds (1.21) of higher NCD risk factor count than women. Individuals residing in urban areas had higher odds (1.86) of higher NCD risk factor count than individuals residing in rural areas.ConclusionAlmost one in three participants had three or more NCD risk factors and several associated variables were identified for men and women that can facilitate in designing intervention programmes.     

Application of nested multiplex polymerase chain reaction respiratory and pneumonia panels in children with severe community-acquired pneumonia

Community-acquired pneumonia (CAP) is a serious clinical concern. A lack of accurate diagnosis could hinder pathogen-directed therapeutic strategies. To solve this problem, we evaluated clinical application of nested multiplex polymerase chain reaction (PCR) in children with severe CAP. We prospectively enrolled 60 children with severe CAP requiring intensive care between December 2019 and November 2021 at a tertiary medical center. Nested multiplex PCR respiratory panel (RP) and pneumonia panel (PP) were performed on upper and lower respiratory tract specimens. We integrated standard-of-care tests and quantitative PCR for validation. The combination of RP, PP, and standard-of-care tests could detect at least one pathogen in 98% of cases and the mixed viral-bacterial detection rate was 65%. The positive percent agreement (PPA), and negative percent agreement (NPA) for RP were 94% and 99%; the PPA and NPA for PP were 89% and 98%. The distribution of pathogens was similar in the upper and lower respiratory tracts, and the DNA or RNA copies of pathogens in the lower respiratory tract were equal to or higher than those in the upper respiratory tract. PP detected bacterial pathogens in 40 (67%) cases, and clinicians tended to increase bacterial diagnosis and escalate antimicrobial therapy for them. RP and PP had satisfactory performance to help pediatricians make pathogenic diagnoses and establish therapy earlier. The pathogens in the upper respiratory tract had predictive diagnostic values for lower respiratory tract infections in children with severe CAP.     

A potent antibody-secreting B cell response to Mycoplasma pneumoniae in children with pneumonia

BackgroundMycoplasma pneumoniae is a major pathogen for community-acquired pneumonia and frequently causes outbreaks in children. M. pneumoniae-specific antibody response is detected upon acute infection and the serology is widely used in the clinical setting. Nevertheless, the cellular basis for antigen-specific antibody response to acute M. pneumoniae infection is largely undetermined in children.MethodsHospitalized children with community-acquired pneumonia were enrolled and the infection with M. pneumoniae was confirmed with positive PCR result and negative findings for other pathogens. The M. pneumoniae P1-specific antibody-secreting B cell (ASC) response was examined with the ex vivo enzyme-linked immunosorbent spot assay and the relationships between the ASC frequency and serological level and clinical parameters within M. pneumoniae patients were studied.ResultsA robust M. pneumoniae P1-specific ASC response was detected in the peripheral blood among M. pneumoniae-positive patients. By contrast, no M. pneumoniae-specific ASCs were detected among M. pneumoniae-negative patients. The IgM-secreting B cells are the predominant class and account for over 60% of total circulating M. pneumoniae-specific ASCs in the acute phase of illness. The M. pneumoniae P1-specific ASC frequency significantly correlated with the fever duration, and the IgG ASC frequency significantly correlated with serological titer among patients.ConclusionA rapid and potent elicitation of peripheral M. pneumoniae-specific ASC response to acute infection provides the cellular basis of antigen-specific humoral response and indicates the potential of cell-based diagnostic tool for acute M. pneumoniae infection. Our findings warrant further investigations into functional and molecular aspects of antibody immunity to M. pneumoniae.     

Primary investigation of 31 infants with suspected congenital rubella syndrome in Sudan

Between 2005 and 2006, clinical specimens were collected from 31 infants with suspected congenital rubella syndrome (CRS) who presented at six hospitals in Khartoum, Sudan. Eleven (35.5%) were laboratory confirmed as CRS cases by testing for anti-rubella IgM, IgG and viral genome. For the first time in Sudan, the rubella virus genome was directly detected in clinical specimens of six CRS cases and two viruses were isolated in cell culture. Phylogenetic analysis suggested that three genotypes of rubella virus (RV; 1E, 2B and 1G) were co-circulating in Sudan. The study introduced the methodology for CRS confirmation and surveillance in Sudan and provides preliminary data.     

An evaluation of clinical stability criteria to predict hospital course in community-acquired pneumonia

A number of different methods exist to assess clinical stability, a key component of pneumonia management. We compared the prognostic value of different stability criteria through a secondary analysis of the Edinburgh pneumonia study database. We studied four clinical stability criteria (Halm's criteria, the ATS criteria, CURB and 50% or more decrease in C-reactive protein from baseline). Outcomes included 30-day mortality, need for mechanical ventilation or vasopressor support (MV/VS), development of a complicated pneumonia, and a combined outcome of the above. A total of 1079 patients (49.8% male), with a median age of 68 years (IQR 53–80), were included. Ninety-three patients (8.6%) died by day 30, 91 patients (8.4%) required MV/VS and 99 patients (9.2%) developed a complicated pneumonia. Patients with increasing severity of pneumonia on admission, assessed by both CURB-65 and PSI, took a progressively longer time to achieve clinical stability assessed by any method (p < 0.001 for all criteria). Halm's criteria had the highest area under the curve (AUC) for prediction of 30-day mortality (AUC 0.95 (0.94–0.96)), need for MV/VS (AUC 0.96 (0.95–0.97)) and combined adverse outcome (AUC 0.96 (0.95–0.97)). C-reactive protein had the highest area under the curve for complicated pneumonia (AUC 0.96 (0.95–0.97)). Adding C-reactive protein to Halm's criteria increased the area under the curve, but the difference was only statistically significant for complicated pneumonia. All of the criteria performed well in predicting adverse outcomes in patients with pneumonia. Halm's criteria performed best when identifying patients at low risk of complications.     

Predicting pneumococcal community-acquired pneumonia in the emergency department: Evaluation of clinical parameters

The aim of this study was to quantify the value of clinical predictors available in the emergency department (ED) in predicting Streptococcus pneumoniae as the cause of community-acquired pneumonia (CAP). A prospective, observational, cohort study of patients with CAP presenting in the ED was performed. Pneumococcal aetiology of CAP was based on either bacteraemia, or S. pneumoniae being cultured from sputum, or urinary immunochromatographic assay positivity, or positivity of a novel serotype-specific urinary antigen detection test. Multivariate logistic regression was used to identify independent predictors and various cut-off values of probability scores were used to evaluate the usefulness of the model. Three hundred and twenty-eight (31.0%) of 1057 patients with CAP had pneumococcal CAP. Nine independent predictors for pneumococcal pneumonia were identified, but the clinical utility of this prediction model was disappointing, because of low positive predictive values or a small yield. Clinical criteria have insufficient diagnostic capacity to predict pneumococcal CAP. Rapid antigen detection tests are needed to diagnose S. pneumoniae at the time of hospital admission.     

Prevalence and correlates of disturbed dreaming in children

Relatively little is known about nightmares and other forms of disturbed dreaming in children. This article reviews the literature on the prevalence and correlates of nightmares in children and highlights key methodological issues in the field. Results show that regardless of how they are defined and measured, nightmares affect a significant proportion of children of all ages and there is some evidence to suggest that nightmare frequency may peak around the age of 10. Gender differences in nightmare frequency, with girls reporting more nightmares than do boys, tend to appear between the ages of 10 and 15. Although nightmares are associated with a range of psychosocial difficulties (e.g., stress, behavioural problems), elevated anxiety and concomitant sleep-related disorders (e.g., sleepwalking) are among the most robust correlates of nightmares. Very few studies have examined nightmare treatment in children, but promising results have been obtained with imagery rehearsal therapy. Overall, research in the field has been hampered by inconsistent definitions for nightmares, by extensive variability in questionnaire items used to measure nightmare frequency, and by a lack of awareness of how using parents versus children as respondents may impact results. Longitudinal studies are needed to better understand how nightmares and their correlates evolve during childhood and adolescence, to delineate their clinical significance, and to develop effective and age-appropriate treatment strategies.     

Th17/Treg失衡在肺炎支原体肺炎患儿中的作用及其机制

目的：探讨Th17/Treg失衡在肺炎支原体肺炎患儿中的作用及其机制。方法：纳入2013年6月至2015年1月我院收治的60例肺炎支原体肺炎急性期患儿和30例同期体检的健康儿童为研究对象。流式细胞术分析两组儿童外周血Th17和Treg的百分率,ELISA分析Th17和Treg特异性细胞因子IL-17和IL-10的分泌水平,定量PCR测定Th17和Treg特异性转录因子RORγt和Foxp3 mRNA的表达水平,以及Notch信号分子(Notch1,Hes1和Hey1)的表达水平。结果：与健康儿童相比,肺炎支原体肺炎急性期患儿外周血的Th17的百分率,IL-17分泌水平以及特异性转录因子RORγt的表达水平均明显增高,差异均具有统计学意义(P<0.05),而急性期患儿外周血的Treg的百分率,IL-10分泌水平以及特异性转录因子Foxp3的表达水平均较健康儿童明显降低,差异均具有统计学意义(P<0.05)。进一步分析显示急性期患儿Notch1、Hes1和Hey1的表达水平均明显高于健康儿童,其差异均具有统计学意义(P<0.05)。结论：Th17/Treg失衡参与儿童支原体肺炎的发生发展,Notch信号通路可能通过调节免疫细胞分化和细胞因子分泌参与Th17/Treg失衡。     

Low incidence of multidrug-resistant organisms in patients with healthcare-associated pneumonia requiring hospitalization

Healthcare-associated pneumonia (HCAP) includes a broad spectrum of patients who acquire pneumonia through outpatient contact with the health system. Although limited prospective data exist, it has been suggested that all patients with HCAP should receive empirical therapy with a multidrug regimen directed against drug-resistant organisms. We aimed to determine the differences in aetiology and outcomes between HCAP groups and a community-acquired pneumonia (CAP) group, and to assess the presence of antibiotic-resistant bacteria. All consecutive non-immunocompromised adults hospitalized with pneumonia were prospectively included from 2001 to 2009. Patients who had had recent contact with the health system through nursing homes, home healthcare programmes, haemodialysis clinics or prior hospitalization were considered to have HCAP. A total of 2245 patients with pneumonia were hospitalized through the emergency room, of whom 577 (25.7%) had HCAP. Significant differences in causative pathogens were found between groups. Antibiotic-resistant organisms, including methicillin-resistant Staphylococcus aureus, resistant strains of Pseudomonas aeruginosa, and extendedspectrum β-lactamase-producing Enterobacteriaceae, were scarce in all groups. In contrast, aspiration pneumonia was particularly frequent. No differences were found regarding inappropriate initial empirical antibiotic therapy between groups. Overall mortality was higher in patients who attended a hospital or haemodialysis clinic or received intravenous chemotherapy in the 30 days before pneumonia, and among patients who resided in a nursing home or long-term-care facility. In conclusion, most HCAP patients could be treated in the same way as patients with CAP, after carefully ruling out the presence of aspiration pneumonia.