Bacteremic pneumococcal pneumonia in Sweden: clinical course and outcome and comparison with non-bacteremic pneumococcal and mycoplasmal pneumonias

Clinical Features and Outcomes of Community-Acquired Pneumonia Caused by Haemophilus Influenza

Background

Long regarded as the second most common cause of community-acquired pneumonia (CAP), Haemophilus influenzae has recently been identified with almost equal frequency as pneumococcus in patients hospitalized for CAP. The literature lacks a detailed description of the presentation, clinical features, laboratory and radiologic findings, and outcomes in Haemophilus pneumonia.

Methods

During 2 prospective studies of patients hospitalized for CAP, we identified 33 patients with Haemophilus pneumonia. In order to provide context, we compared clinical findings in these patients with findings in 36 patients with pneumococcal pneumonia identified during the same period. We included and analyzed separately data from patients with viral coinfection. Patients with coinfection by other bacteria were excluded.

Results

Haemophilus pneumonia occurred in older adults who had underlying chronic lung disease, cardiac conditions, and alcohol use disorder, the same population at risk for pneumococcal pneumonia. However, in contrast to pneumococcal pneumonia, patients with Haemophilus pneumonia had less severe infection as shown by absence of septic shock on admission, less confusion, fewer cases of leukopenia or extreme leukocytosis, and no deaths at 30 days. Viral coinfection greatly increased the severity of Haemophilus, but not pneumococcal pneumonia.

Conclusions

We present the first thorough description of Haemophilus pneumonia, show that it is less severe than pneumococcal pneumonia, and document that viral coinfection greatly increases its severity. These distinctions are lost when the label CAP is liberally applied to all patients who come to the hospital from the community for pneumonia.

Assessment of Empiric Vancomycin Regimen in the Neonatal Intensive Care Unit

BACKGROUND

Vancomycin is used to treat serious gram-positive infections in neonates. Currently, there is no consensus on the preferred empiric dosing regimen or target trough vancomycin levels for neonates. The current Fraser Health empiric dosing regimen, implemented in 2010, was designed to achieve target trough levels of 5 to 15 mg/L.

OBJECTIVES

To determine the percentage of neonates receiving vancomycin in whom target trough levels of 5 to 15 mg/L were achieved, to identify the times to negative culture result and clinical resolution, and to determine the incidence of nephrotoxicity.

METHODS

A chart review was completed for patients who had received vancomycin in the neonatal intensive care unit of either Surrey Memorial Hospital or Royal Columbian Hospital from June 2012 to May 2017 and for whom at least 1 interpretable vancomycin level was available.

RESULTS

A total of 87 vancomycin encounters (in 78 neonates) were identified in which the drug had been given according to the Fraser Health empiric dosing regimen. Target trough vancomycin level (5 to 15 mg/L) was achieved in 75% of these encounters. The mean times to negative culture result and clinical resolution were 5 and 6 days, respectively. There was no statistically significant correlation between vancomycin level and time to clinical resolution (rs = 0.366, p = 0.072). Among cases in which the trough vancomycin level exceeded 15 mg/L, the incidence of nephrotoxicity was 22% (4/18).

CONCLUSIONS

The current Fraser Health empiric dosing regimen for vancomycin achieved target trough levels of the drug for most neonates in this study. Targeting trough levels less than 15 mg/L when appropriate to the infection type may limit nephrotoxicity associated with vancomycin in neonates. Further studies are needed to evaluate the clinical significance of various vancomycin levels.

Management of community-acquired pneumonia in immunocompetent adults: updated Swedish guidelines 2017

Based on expert group work, Swedish recommendations for the management of community-acquired pneumonia in adults are here updated. The management of sepsis-induced hypotension is addressed in detail, including monitoring and parenteral therapy. The importance of respiratory support in cases of acute respiratory failure is emphasized. Treatment with high-flow oxygen and non-invasive ventilation is recommended. The use of statins or steroids in general therapy is not found to be fully supported by evidence. In the management of pleural infection, new data show favourable effects of tissue plasminogen activator and deoxyribonuclease installation. Detailed recommendations for the vaccination of risk groups are afforded.

Pneumococcal Disease Prevention Among Adults: Strategies for the Use of Pneumococcal Vaccines

Use of the pneumococcal conjugate vaccines among children in the U.S. since 2000 has dramatically reduced pneumococcal disease burden among adults. Significant vaccine-preventable morbidity and mortality from pneumococcal infections still remains, especially among older adults. The U.S. Advisory Committee on Immunization Practices (ACIP) has recently recommended the routine use of both pneumococcal conjugate (PCV13) and polysaccharide vaccines (PPSV23) for adults ≥65 years. These recommendations were based on the remaining burden of illness among adults and the importance of non-bacteremic pneumonia prevention in light of new evidence confirming the efficacy of PCV13 to prevent pneumococcal pneumonia among older adults. This paper reviews the evidence that led ACIP to make recommendations for PCV13 and PPSV23 use among adults, and highlights potential gaps to be addressed by future studies to inform adult vaccination policy. The changing epidemiology of invasive pneumococcal disease and pneumonia should be closely monitored to evaluate the effectiveness and continued utility of the current vaccination strategy, and to identify future directions for pneumococcal disease prevention among older adults.

Pneumococcal disease prevention among adults: Strategies for the use of pneumococcal vaccines

Use of the pneumococcal conjugate vaccines among children in the US since 2000 has dramatically reduced pneumococcal disease burden among adults. Significant vaccine-preventable morbidity and mortality from pneumococcal infections still remains, especially among older adults. The US Advisory Committee on Immunization Practices (ACIP) has recently recommended the routine use of both pneumococcal conjugate (PCV13) and polysaccharide vaccines (PPSV23) for adults ≥65 years. These recommendations were based on the remaining burden of illness among adults and the importance of non-bacteremic pneumonia prevention in light of new evidence confirming the efficacy of PCV13 to prevent pneumococcal pneumonia among older adults. This paper reviews the evidence that led the ACIP to make recommendations for PCV13 and PPSV23 use among adults, and highlights potential gaps to be addressed by future studies to inform adult vaccination policy. The changing epidemiology of invasive pneumococcal disease and pneumonia should be closely monitored to evaluate the effectiveness and continued utility of the current vaccination strategy, and to identify future directions for pneumococcal disease prevention among older adults.

Epidemiology of pneumococcal disease in a national cohort of older adults

Introduction

Streptococcus pneumoniae is a major cause of morbidity and mortality. We sought to describe the epidemiology of non-invasive and invasive pneumococcal disease in a national Veterans Affairs population within the United States.

Methods

We conducted a retrospective study in older patients (aged ≥50 years) with positive pneumococcal cultures from any site between 2002 and 2011. We described outpatient and inpatient pneumococcal disease incidence per 100,000 clinic visits/hospitalizations. Repeat cultures within a 30-day period were considered to represent the same episode. To describe the epidemiology of serious pneumococcal infections (bacteremia, meningitis, pneumonia), we assessed demographics, clinical characteristics, and risk factors for S. pneumoniae. Pneumonia was defined as a positive respiratory culture with a pneumonia diagnosis code. Bacteremia and meningitis were identified from positive cultures. Generalized linear mixed models were used to quantify changes over time.

Results

Over the study period, we identified 45,983 unique episodes of pneumococcal disease (defined by positive cultures). Incidence decreased significantly by 3.5% per year in outpatients and increased non-significantly by 0.2% per year in inpatients. In 2011, the outpatient and inpatient incidence was 2.6 and 328.1 infections per 100,000 clinic visits/hospitalizations, respectively. Among inpatients with serious infections, chronic disease risk factors for pneumococcal disease increased significantly each year, including respiratory disease (1.9% annually), diabetes (1.3%), and renal failure (1.0%). Overall, 30.2% of inpatients with serious infections had a pneumococcal immunization in the previous 5 years. Invasive disease (37.4% versus 34.9%, P = 0.004) and mortality (14.0% versus 12.7%, P = 0.045) were higher in non-vaccinated patients compared to vaccinated patients.

Conclusions

In our national study of older adults, the baseline health status of those with serious pneumococcal infections worsened over the study period. As the population ages and the chronic disease epidemic grows, the burden of pneumococcal disease is likely to increase thus highlighting the importance of pneumococcal vaccination.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0025-y) contains supplementary material, which is available to authorized users.

Pneumococcus

Pneumococcus is one of the most common bacterial pathogens encountered in medicine. This article summarizes the risk factors, pathogenesis, treatment, and prevention of the spectrum of disease caused by pneumococcus with particular emphasis on antibiotic resistance as well as immunization. This information is useful for physicians caring for patients both as inpatients and outpatients as well as for those concerned with public health and disease prevention.

Swedish guidelines on the management of community-acquired pneumonia in immunocompetent adults--Swedish Society of Infectious Diseases 2012

This document presents the 2012 evidence based guidelines of the Swedish Society of Infectious Diseases for the in- hospital management of adult immunocompetent patients with community-acquired pneumonia (CAP). The prognostic score 'CRB-65' is recommended for the initial assessment of all CAP patients, and should be regarded as an aid for decision-making concerning the level of care required, microbiological investigation, and antibiotic treatment. Due to the favourable antibiotic resistance situation in Sweden, an initial narrow-spectrum antibiotic treatment primarily directed at Streptococcus pneumoniae is recommended in most situations. The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations. In critically ill patients (CRB-65 score 3-4), combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended. A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease. Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation.

Of mice and men: innate immunity in pneumococcal pneumonia

Pneumococcal pneumonia is characterised by an intense inflammatory response induced mainly by cell wall components of the bacterium. Recognition of cell wall components by Toll-like receptors (TLRs) induces intracellular signalling pathways that culminate in the activation of pro-inflammatory genes through nuclear factor kappaB (NF-kappaB). Tumour necrosis factor-alpha (TNFalpha) is one of the earliest mediators produced and induces a second wave of pro- and anti-inflammatory cytokines that orchestrate the immune response. The magnitude of this response in patients with pneumococcal pneumonia is a complex network and many factors must be considered in the analysis of the cytokine production pattern. First, bacterial growth and the inflammatory response are dynamic processes, produced initially as a local phenomenon with a late systemic extension. Second, host characteristics, such as different cytokine gene polymorphisms, can cause a distinct immune response. Finally, other microorganism determinants and even the immunomodulatory effect of antimicrobials may play a role in cytokine production. Recent data on innate immunity against Streptococcus pneumoniae gathered from the murine model of pneumonia, from studies of human genetic polymorphisms associated with increased susceptibility to pneumococcal infection, and from human clinical trials are discussed. Special emphasis has been placed on the description of the chronology of the complex network of innate immunity triggered by pneumococcal infection.

Systemic expression of cytokine production in patients with severe pneumococcal pneumonia: effects of treatment with a beta-lactam versus a fluoroquinolone

Bacterial alveolar invasion is followed by an inflammatory response. A systemic extension of the compartmentalized immune response has been described in patients with severe pneumonia. The data suggest that some antimicrobials may induce a differential release of cytokines. We conducted a prospective, randomized study in adult patients with severe pneumococcal pneumonia to measure the effects of ceftriaxone and levofloxacin in the systemic cytokine expression over time. Demographic, clinical characteristics, and severity scores were recorded. The serum concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, IL-8, IL-10, and IL-1 receptor agonist were measured at 0, 24, 72, and 120 h. A total of 32 patients were included in the study. Both groups were homogeneous in terms of age, comorbidities, severity of disease, and corticosteroid or statin use. With the single exception of IL-1beta, all cytokines were detected in venous blood. All of the cytokines studied showed a similar pattern of progressive decrease over time. No significant differences in the concentrations of any of the cytokines studied were found, with the exception of TNF-alpha, for which lower concentrations were obtained at 120 h in the levofloxacin group (P = 0.014). Basal oxygen saturation (P = 0.034) and heart rate (P = 0.029) returned to normal values earlier in the levofloxacin arm. We demonstrated that in patients with severe pneumococcal pneumonia pro- and anti-inflammatory responses could be detected in venous blood, representing a systemic extension of the compartmentalized response. Treatment with a beta-lactam agent or a fluoroquinolone has different effects on cytokine production and its systemic expression, impacting the clinical course of the disease.

A comparative study of bacteremic and non-bacteremic pneumococcal pneumonia

BACKGROUND

Few attempts have been made to compare bacteremic and non-bacteremic pneumococcal pneumonia, mainly because it is difficult to gain agreement on which cases represent non-bacteremic pneumococcal pneumonia. Recently, an immunochromatographic assay for the detection of Streptococcus pneumoniae urinary antigen has been successfully evaluated for the diagnosis of pneumococcal pneumonia. The aim of our study was to examine and compare clinical and radiological features, risk factors, and outcome associated with bacteremic and non-bacteremic groups.

METHODS

A retrospective study (1995-2003) analyzing the clinical records of patients diagnosed with pneumococcal pneumonia in our institution was performed. S. pneumoniae were identified by blood cultures (bacteremic group) and detection of urinary antigen (non-bacteremic group).

RESULTS

There were 82 patients (57 bacteremic and 25 non-bacteremic). In seven non-bacteremic cases, another etiology was detected, i.e., Legionella (n=1) and Chlamydia pneumoniae (n=6). Bacteremic patients were significantly younger (p=<0.001), more likely to have liver disease (p=0.028), current smokers (p=0.024), alcohol and intravenous drug abusers (p=0.014 and p<0.001, respectively), and infected with HIV (p<0.001). Non-bacteremic patients were more likely to have congestive heart failure (p=0.004), chronic obstructive pulmonary disease (p=0.033) and to be former smokers (p=0.004). Bacteremic cases needed more prolonged intravenous antibiotic treatment (6 days vs. 4.5 days; p=0.006) than non-bacteremic cases and their length of stay was also longer.

CONCLUSION

In our study, smoking was the leading risk factor for pneumococcal pneumonia. However, current smokers have an increased risk of bacteremic forms and former smokers and patients with COPD developed non-bacteremic forms more frequently. Bacteremic patients need more prolonged intravenous antibiotic treatment than non-bacteremic patients.

Obesity and smoking are factors associated with poor prognosis in patients with bacteraemia

Background

Bacteraemia is still a major cause of case fatality in all age groups. Our aim was to identify the major underlying conditions constituting risk factors for case fatality in bacteraemia patients.

Methods

The study involved 149 patients (79 male and 70 female) with bacteraemia caused by Staphylococcus aureus (S. aureus) (41 patients), Streptococcus pneumoniae (Str. pneumoniae) (42 patients), β-hemolytic streptococcae (β-hml str.) (23 patients) and Eschericia coli (E. coli) (43 patients). Underlying diseases, alcohol and tobacco consumption and body mass index (BMI) were registered. Laboratory findings and clinical data were registered on admission and 6 consecutive days and on day 10–14. Case fatality was studied within 30 days after positive blood culture. Associations between underlying conditions and case fatality were studied in univariate analysis and in a multivariate model.

Results

Nineteen patients (12.8%) died of bacteraemia. We found obesity (p = 0.002, RR 9.8; 95% CI 2.3 to 41.3), smoking (p < 0.001, RR 16.9; 95% CI 2.1 to 133.5), alcohol abuse (p = 0.008, RR 3.9; 95% CI 1.3 to 11.28), COPD (p = 0.01, RR 8.4; 95% CI 1.9 to 37.1) and rheumatoid arthritis (p = 0.045, RR 5.9; 95% CI 1.2 to 28.8) to be significantly associated with case fatality in bacteraemia in univariate model. The median BMI was significantly higher among those who died compared to survivors (33 vs. 26, p = 0.003). Obesity and smoking also remained independent risk factors for case fatality when their effect was studied together in a multivariate model adjusted with the effect of alcohol abuse, age (continuos variable), sex and causative organism.

Conclusion

Our results indicate that obesity and smoking are prominent risk factors for case fatality in bacteraemic patients. Identification of risk factors underlying fatal outcome in bacteraemia may allow targeting of preventive efforts to individuals likely to derive greatest potential benefit.

Swedish guidelines for the management of community-acquired pneumonia in immunocompetent adults

This document presents the evidence-based guidelines of the Swedish Society of Infectious Diseases for the management of adult immunocompetent patients with community-acquired pneumonia (CAP), who are assessed at hospital. The prognostic score 'CURB-65' is recommended for all CAP patients in the emergency room. The score provides an assessment tool for the decision regarding outpatient treatment or level of hospital supervision, the choice of microbiological investigations, and empirical antibiotic treatment. In patients with non-severe CAP (CURB-65 score 0-2) we recommend initial narrow-spectrum antibiotic treatment, orally or intravenously, primarily directed at Streptococcus pneumoniae. In those with CURB-65 score 3, penicillin G or a cephalosporin intravenously is recommended. For CURB-65 score 0-3 atypical pathogens should be covered only when they are suspected on clinical or epidemiological grounds. In patients with CURB-65 score 4-5 intravenous combination therapy with either cephalosporin/macrolide or penicillin G/fluoroquinolone is recommended. Efforts should be made to identify the CAP aetiology in order to support the ongoing antibiotic treatment or to suggest treatment alterations. Recommended measures for prevention of CAP include influenza -- and pneumococcal -- vaccination to risk groups and efforts for smoking cessation.

Rhabdomyolysis as a result of Streptococcus pneumoniae: report of a case and review

We report the case of a patient who presented with RM associated with bacteremic pneumococcal pneumonia and review the literature on this condition.

Severe community-acquired pneumonia: use of intensive care services and evaluation of American and British Thoracic Society Diagnostic criteria

Despite careful evaluation of changes in hospital care for community-acquired pneumonia (CAP), little is known about intensive care unit (ICU) use in the treatment of this disease. There are criteria that define CAP as "severe," but evaluation of their predictive value is limited. We compared characteristics, course, and outcome of inpatients who did (n = 170) and did not (n = 1,169) receive ICU care in the Pneumonia Patient Outcomes Research Team prospective cohort. We also assessed the predictive characteristics of four prediction rules (the original and revised American Thoracic Society criteria, the British Thoracic Society criteria, and the Pneumonia Severity Index [PSI]) for ICU admission, mechanical ventilation, medical complications, and death (as proxies for severe CAP). ICU patients were more likely to be admitted from home and had more comorbid conditions. Reasons for ICU admission included respiratory failure (57%), hemodynamic monitoring (32%), and shock (16%). ICU patients incurred longer hospital stays (23.2 vs. 9.1 days, p < 0.001), higher hospital costs (21,144 dollars vs. 5,785 dollars, p < 0.001), more nonpulmonary organ dysfunction, and higher hospital mortality (18.2 vs. 5.0%, p < 0.001). Although ICU patients were sicker, 27% were of low risk (PSI Risk Classes I-III). Severity-adjusted ICU admission rates varied across institutions, but mechanical ventilation rates did not. The revised American Thoracic Society criteria rule was the best discriminator of ICU admission and mechanical ventilation (area under the receiver operating characteristic curve, 0.68 and 0.74, respectively) but none of the prediction rules were particularly good. The PSI was the best predictor of medical complications and death (area under the receiver operating characteristic curve, 0.65 and 0.75, respectively), but again, none of the prediction rules were particularly good. In conclusion, ICU use for CAP is common and expensive but admission rates are variable. Clinical prediction rules for severe CAP do not appear adequately robust to guide clinical care at the current time.

Clinical presentation, processes and outcomes of care for patients with pneumococcal pneumonia

OBJECTIVE

To describe the presentation, resolution of symptoms, processes of care, and outcomes of pneumococcal pneumonia, and to compare features of the bacteremic and nonbacteremic forms of this illness.

DESIGN

A prospective cohort study.

SETTING

Five medical institutions in 3 geographic locations.

PARTICIPANTS

Inpatients and outpatients with community-acquired pneumonia (CAP).

MEASUREMENTS

Sociodemographic characteristics, respiratory and nonrespiratory symptoms, and physical examination findings were obtained from interviews or chart review. Severity of illness was assessed using a validated prediction rule for short-term mortality in CAP. Pneumococcal pneumonia was categorized as bacteremic; nonbacteremic, pure etiology; or nonbacteremic, mixed etiology.

MAIN RESULTS

One hundred fifty-eight (6.9%) of 2,287 patients (944 outpatients, 1,343 inpatients) with CAP had pneumococcal pneumonia. Sixty-five (41%) of the 158 with pneumococcal pneumonia were bacteremic; 74 (47%) were nonbacteremic with S. pneumoniae as sole pathogen; and 19 (12%) were nonbacteremic with S. pneumoniae as one of multiple pathogens. The pneumococcal bacteremia rate for outpatients was 2.6% and for inpatients it was 6.6%. Cough, dyspnea, and pleuritic pain were common respiratory symptoms. Hemoptysis occurred in 16% to 22% of the patients. A large number of nonrespiratory symptoms were noted. Bacteremic patients were less likely than nonbacteremic patients to have sputum production and myalgias (60% vs 82% and 33% vs 57%, respectively; P <.01 for both), more likely to have elevated blood urea nitrogen and serum creatinine levels, and more likely to receive penicillin therapy. Half of bacteremic patients were in the low risk category for short-term mortality (groups I to III), similar to the nonbacteremic patients. None of the 32 bacteremic patients in risk groups I to III died, while 7 of 23 (30%) in risk group V died. Intensive care unit admissions and pneumonia-related mortality were similar between bacteremic and nonbacteremic groups, although 46% of the bacteremic group had respiratory failure compared with 32% and 37% for the other groups. The nonbacteremic pure etiology patients returned to household activities faster than bacteremic patients. Symptoms frequently persisted at 30 days: cough (50%); dyspnea (53%); sputum production (48%); pleuritic pain (13%); and fatigue (63%).

CONCLUSIONS

There were few differences in the presentation of bacteremic and nonbacteremic pneumococcal pneumonia. About half of bacteremic pneumococcal pneumonia patients were at low risk for mortality. Symptom resolution frequently was slow.

Bacteremic and nonbacteremic pneumococcal pneumonia. A prospective study

We prospectively identified cases of pneumococcal pneumonia and used stringent criteria to stratify them into bacteremic and nonbacteremic cases. Although patients were distributed among racial groups in proportion to all patients seen at this medical center, the proportion of African-Americans with bacteremic disease was significantly increased. All patients had at least 1 underlying condition predisposing to pneumococcal infection, and most had several. Although the mean number of predisposing factors was greater among bacteremic patients than nonbacteremic patients, only alcohol ingestion was significantly more common. Nearly one-third of patients had substantial anemia (hemoglobin < or = 10 g/dL) on admission, which may have predisposed to infection. In the case of other laboratory abnormalities, such as albumin, creatinine, and bilirubin, it was difficult to determine which abnormality might have predisposed to pneumococcal infection and which might have resulted from it. The radiologic appearance was varied. Airspace consolidation and air bronchogram on chest X-ray were highly associated with bacteremic disease, as was the presence of pleural effusion. Although the Pneumonia Patient Outcomes Research Team (PORT) risk score was a predictor of mortality, it did not help to predict the presence of bacteremia in an individual case. Most patients who died in the first week in hospital were bacteremic, and a high PORT risk score with bacteremia reliably predicted a high likelihood of a fatal outcome. Eleven patients had extrapulmonary disease with meningitis, empyema, and septic arthritis predominating; all of these patients were bacteremic. The antibiotic susceptibility of our strains correlated well with those that have been reported in the United States during the years of this study. The use of numerous antibiotics of different classes in many patients, especially those who were the most ill, precluded analysis of outcome based on antibiotic therapy. Only 17 patients had been vaccinated. Since nearly all patients had conditions for which pneumococcal vaccine is recommended and more than one-third had been hospitalized in the preceding 6 months, the low rate of vaccination can be regarded as a missed opportunity to administer a potentially beneficial vaccine.

Mortality from invasive pneumococcal pneumonia in the era of antibiotic resistance, 1995-1997

OBJECTIVES

This study examined epidemiologic factors affecting mortality from pneumococcal pneumonia in 1995 through 1997.

METHODS

Persons residing in a surveillance area who had community-acquired pneumonia requiring hospitalization and Streptococcus pneumoniae isolated from a sterile site were included in the analysis. Factors affecting mortality were evaluated in univariate and multivariate analyses. The number of deaths from pneumococcal pneumonia requiring hospitalization in the United States in 1996 was estimated.

RESULTS

Of 5837 cases, 12% were fatal. Increased mortality was associated with older age, underlying disease. Asian race, and residence in Toronto/Peel, Ontario. When these factors were controlled for, increased mortality was not associated with resistance to penicillin or cefotaxime. However, when deaths during the first 4 hospital days were excluded, mortality was significantly associated with penicillin minimum inhibitory concentrations of 4.0 or higher and cefotaxime minimum inhibitory concentrations of 2.0 or higher. In 1996, about 7000 to 12,500 deaths occurred in the United States from pneumococcal pneumonia requiring hospitalization.

CONCLUSIONS

Older age and underlying disease remain the most important factors influencing death from pneumococcal pneumonia. Mortality was not elevated in most infections with beta-lactam-resistant pneumococci.

Etiology of community-acquired pneumonia: impact of age, comorbidity, and severity

The aim of this study was to determine the etiology of community-acquired pneumonia (CAP) and the impact of age, comorbidity, and severity on microbial etiologies of such pneumonia. Overall, 395 consecutive patients with CAP were studied prospectively during a 15-mo period. Regular microbial investigation included examination of sputum, blood culture, and serology. Sampling of pleural fluid, transthoracic puncture, tracheobronchial aspiration, and protected specimen brush (PSB) sampling were performed in selected patients. The microbial etiology was determined in 182 of 395 (46%) cases, and 227 pathogens were detected. The five most frequent pathogens were Streptococcus pneumoniae (65 patients [29%]), Haemophilus influenzae (25 patients [11%]), Influenza virus A and B (23 patients [10%]), Legionella sp. (17 patients [8%]), and Chlamydia pneumoniae (15 patients [7%]). Gram-negative enteric bacilli (GNEB) accounted for 13 cases (6%) and Pseudomonas aeruginosa for 12 cases of pneumonia (5%). Patients aged < 60 yr were at risk for an "atypical" bacterial etiology (odds ratio [OR]: 2.3; 95% confidence interval [CI]: 1.2 to 4.5), especially Mycoplasma pneumoniae (OR: 5.3; 95% CI: 1.7 to 16.8). Comorbid pulmonary, hepatic, and central nervous illnesses, as well as current cigarette smoking and alcohol abuse, were all associated with distinct etiologic patterns. Pneumonia requiring admission to the intensive care unit was independently associated with the pathogens S. pneumoniae (OR: 2.5; 95% CI: 1.3 to 4.7), gram-negative enteric bacilli, and P. aeruginosa (OR: 2.5; 95% CI: 0.99 to 6.5). Clinical and radiographic features of "typical" pneumonia were neither sensitive nor specific for the differentiation of pneumococcal and nonpneumococcal etiologies. These results support a management approach based on the associations between etiology and age, comorbidity, and severity, instead of the traditional syndromic approach to CAP.

Pneumococcal disease in Sweden: experiences and current situation

During the last decade, the incidence of invasive pneumococcal disease in Sweden has risen, seemingly due chiefly to an increasing incidence of pneumococcal bacteremia among the elderly. On the other hand, mortality due to invasive disease in Sweden is low, approximately 10% for bacteremic pneumococcal pneumonia. Beta-lactam resistance in Streptococcus pneumoniae is still a relatively minor problem in Sweden, with only 3%-4% of strains demonstrating decreased susceptibility to penicillin. However, local outbreaks of pneumococcal disease with up to 10% resistance have occurred among children, especially in southern Sweden.

Hospital admissions in children due to pneumococcal pneumonia in England

Hospital records of 116 children under 5 years of age discharged from 11 hospitals in three regions in England with a diagnosis of lobar (pneumococcal) pneumonia were reviewed to estimate the proportion likely to be attributable to infection with Streptococcus pneumoniae. Of these, 100 (86%) had lobar/focal changes on chest X-ray consistent with pneumococcal infection, although only one (1%) had pneumococcus isolated from blood. However, a further 89 (89%) with a lobar/focal picture were considered to be likely or possibly due to pneumococcal infection on the basis of the white cell count, level of C-reactive protein, isolation of the S. pneumoniae from either sputum or nasopharingeal aspirate and failure to identify another responsible pathogen. Of 135 cases with a discharge diagnosis of bronchopneumonia or pneumonia (organism unspecified), two (1%) had S. pneumoniae isolated from blood and a further 95 (70%) had clinical or laboratory features consistent with pneumococcal infection or S. pneumoniae isolated from either sputum or nasopharyngeal aspirate. With the imminent availability of conjugate pneumococcal vaccines, there is a need for improved diagnostic methods for identifying the pathogens responsible for community-acquired pneumonia in young children.

Early recognition of Streptococcus pneumoniae in patients with community-acquired pneumonia

The objective of this study was to assess the predictive value of signs, symptoms, and rapidly available laboratory parameters for pneumococci in community-acquired pneumonia (CAP). A prospective study on patients with CAP who were admitted to hospital was conducted. Clinical and laboratory data were collected according to a protocol. Two hundred sixty-eight patients aged 18 years or older, not living in a nursing home or not admitted to hospital within one week of this admission, with a new infiltrate on the chest radiograph consistent with pneumonia were included. According to microbiological and serological tests, patients were allocated to one of two aetiological groups, Streptococcus pneumoniae or "other pathogens". Seventy-three variables were examined for a correlation with one of the aetiological categories by means of univariate and multivariate analysis. The resulting discriminant function was considered a clinical test for which posttest probabilities for pneumococcal pneumonia were calculated. Streptococcus pneumoniae was demonstrated in 79 patients and other pathogens in 83; no pathogens were detectable in 106 patients. The variables "cardiovascular disease", "acute onset", "pleuritic pain", "gram-positive bacteria in the sputum Gram stain", and "leucocyte count" correctly predicted the cause of CAP in 80% of all cases in both groups. Depending on the prevalence of Streptococcus pneumoniae, posttest probabilities for pneumococcal pneumonia were up to 90%. It is concluded that data on history, together with the result of the Gram stain of sputum and the leucocyte count, can help to distinguish Streptococcus pneumoniae from other pathogens causing CAP.

Bacteraemic pneumococcal disease in a teaching hospital in Finland

A total of 94 adult patients with bacteraemic pneumococcal disease were retrospectively analyzed for the factors associated with a fatal outcome. Included there were 61 males and 33 females with a mean age of 54.1 =/- 17.7 years. Of all patients, 28 (29.8%) were previously healthy, 66 (70.2%) had at least one chronic underlying disease and 29 (30.9%) were classified as alcohol abusers. The total case-fatality rate was 34%, which is higher than in the other recent Scandinavian studies. The disease was fulminant in 13 patients who died within 24 hours of admission. The mortality was significantly higher among those patients who had underlying diseases than among those who were previously healthy (p = 0.03). In addition, unfavourable prognosis was associated with septic shock on arrival (p = 0.03) respiratory insufficiency requiring mechanical ventilation (p < 0.05) and nosocomial infection (p = 0.03). The patients who succumbed were significantly older that those who survived (p < 0.01). Moreover, the absence of leucocytosis, thrombocytopenia and elevated serum creatinine levels predicted an unfavourable outcome. Contradictory to some previous reports, increased mortality was associated neither with the male sex, alcohol abuse nor the focus of infection. The continuously high mortality and rapid lethality of bacteraemic pneumococcal disease underscore the importance of following the present recommendations on the use of pneumococcal vaccine in high-risk patients.

Severe community-acquired pneumonia. Etiology, epidemiology, and prognosis factors. French Study Group for Community-Acquired Pneumonia in the Intensive Care Unit

A prospective study of 132 patients with severe community-acquired pneumonia (CAP) treated in the ICU was carried out to determine the causative agents, the value of the clinical, biological, and radiologic features in predicting the etiology, and to define prognostic factors. The study group included 98 men and 34 women (mean age: 58 +/- 18 years). The most frequent underlying condition was COPD (51 patients, 39 percent). On admission, 35 patients were in shock, 71 were mentally confused, and 81 (61 percent) required mechanical ventilation during their hospitalization. The clinical, laboratory, and radiologic parameters were of little value for predicting the etiology in patients with severe CAP. An etiologic diagnosis was made in 95 (72 percent) patients. The most frequent pathogens were Streptococcus pneumoniae (43 cases [45 percent]), Gram-negative bacilli (14 cases [15 percent]), and Haemophilus influenzae (14 cases [15 percent]) Mortality was 24 percent. It was significantly associated with a age more than 60 years, septic shock, impairment of alertness, mechanical ventilation requirement, bacteremic pneumonia, and S pneumoniae or Enterobacteriaceae as the causes of the pneumonia. Recommendations for antibiotic chemotherapy in patients with severe CAP admitted to the ICU are included.

Quality of published reports of the prognosis of community-acquired pneumonia

OBJECTIVE

To systematically assess the quality of published reports of the prognosis of community-acquired pneumonia using a formal quality assessment instrument.

DESIGN

Retrospective review of studies published during 1966-1991. ARTICLES: 108 articles related to the prognosis of community-acquired pneumonia retrieved by a computerized search.

INTERVENTION

All articles, blinded to author(s), journal title, year of publication, and study institution(s), were independently reviewed by two investigators using a ten-item quality assessment instrument designed to evaluate: 1) identification of the inception cohort (4 items), 2) description of referral patterns (1 item), 3) subject follow-up (2 items), and 4) statistical methods (3 items). Adherence to each of the ten individual quality items and an overall quality score were calculated for all articles and across three time periods.

MAIN RESULTS

Among all 108 articles that underwent quality assessment, 30 were published from 1966 to 1979, 61 from 1980 through 1989, and 17 from 1990 through 1991. The mean total quality score of all articles was 0.55 (range 0.22-0.90). There was a significant trend toward improvement in total quality scores over the three time periods (0.50 to 0.56 to 0.65; p < 0.001). However, several systematic errors in the study design or reporting of these studies were discovered throughout time: only 3.7% provided comparative information about nonenrolled patients, 28.7% determined whether the study institution was a referral center, 36.1% specified inclusion or exclusion criteria, and 45.5% used appropriate statistical analyses to adjust for more than one prognostic factor.

CONCLUSIONS

Despite improvement in overall quality of published articles, systematic errors exist in the design and reporting of studies related to the prognosis of community-acquired pneumonia. The quality assessment tool employed in this study could be used to guide the development of high-quality outcomes research in the future.

Immunogenicity of the 23-valent pneumococcal polysaccharide vaccine in Alaska Native chronic alcoholics compared with nonalcoholic Native and non-Native controls

PURPOSE

This study was designed to evaluate the immunogenicity of the 23-valent pneumococcal polysaccharide vaccine in Alaska Native chronic alcoholics and compare these responses with those in age- and sex-matched nonalcoholic, Native and non-Native control subjects.

PATIENTS AND METHODS

Native alcoholic patients were recruited from the inpatient medical service and outpatient clinics. Healthy age- and sex-matched Alaska Native and non-Native nonalcoholics were recruited from hospital employees. At the initial visit, a standardized questionnaire, the Alcohol Dependency Scale, was administered to all participants. Participants were examined for liver diseases; blood was drawn for liver function tests and prevaccination pneumococcal antibody levels. Charts of all Native participants were reviewed for alcohol-related diseases. Participants received one dose of the 23-valent pneumococcal vaccine at the time of the initial visit and returned 20 to 55 days after immunization for liver function tests and pneumococcal antibody level measurement. Serotype-specific pneumococcal antibody levels were measured by radioimmunoassay. Logistic regression analysis was used to examine the proportion of persons whose serotype-specific antibody level doubled following vaccination. A model including adjustments for age, sex, and initial antibody level was used to examine the effect of alcohol status and ethnicity on response to the vaccine. Eighty-five persons completed the study. Of these, 41 were chronic alcoholics and 44 were nonalcoholic. Of these, 21 were Alaska Natives and 23 were non-Natives.

RESULTS

Before vaccination, the geometric mean titers (GMTs) were similar in all 3 groups but were slightly higher in Native alcoholic participants for 11 of 12 serotypes tested. For 11 or more serotypes tested, 46% of alcoholics and 27% of nonalcoholics had total antibody levels at or above 500 nanograms of antibody nitrogen per milliliter (p = 0.11). After vaccination, the GMTs were higher in nonalcoholic than in alcoholic participants for serotypes 3, 7F, and 19F (p < 0.05). When Natives and non-Natives were compared, non-Natives had higher antibody levels than Native participants for 10 of 12 serotypes. After vaccination, 83% of alcoholics and 91% of nonalcoholics had pneumococcal antibody levels of more than 500 nanograms of antibody nitrogen per milliliter for at least 11 serotypes. When responses consisting of a twofold or greater increase in antibody level were compared, a greater proportion of nonalcoholics than alcoholics responded to serotypes 3, 4, 7F, 8, and 19F. This difference was significant for types 3 and 19F only (p < 0.05). In alcoholics there was a direct correlation between pneumococcal antibody level and age both before and after vaccination. This was significant before vaccination for serotypes 4, 6B, 18C, and 23F, and after vaccination for these types and for types 1 and 19F. In nonalcoholics there was a correlation between age and antibody response, following vaccination, for serotype 9N and 18C. Alcoholic males had antibody levels higher than that in females for most serotypes, but significantly so only for serotype 12F before vaccination, and for type 14 after vaccination. There were no sex differences seen among nonalcoholics, and no differences in response to vaccine could be detected in patients with or without liver dysfunction.

CONCLUSION

In this study of Alaska Natives with chronic alcoholism, Native and non-Native participants responded adequately to immunization with the 23-valent pneumococcal vaccine, although significant differences in some serotypes were evident.

Deaths in bacteremic pneumococcal pneumonia. A comparison of two populations--Huntington, WVa, and Stockholm, Sweden

The case fatality rate in bacteremic pneumococcal pneumonia (Pnb) has been reported to be lower in Sweden than in the United States. We retrospectively compared 231 adult Pnb patients in Stockholm (STO), Sweden, with 107 patients infected with the same serotypes or groups in Huntington, WVa (HWV). The total case fatality rate was 11/231 (5 percent) in STO versus 28/107 (26 percent) in HWV (p < 0.001), being significantly lower in STO for all age groups. Patients from HWV more often had preexisting chronic diseases, while alcoholism was more prevalent in STO. The case fatality rate was similar among alcoholics in STO and HWV, while it was much higher in nonalcoholic patients with chronic diseases in HWV (22/73;30 percent) than in STO (2/88;2 percent) (p < 0.001). No bias was found that could account for more than a small part of the higher case fatality rate in HWV. Thus, underlying chronic diseases in HWV accounted for some of the increased risk of death in this patient group. However, the major part of the difference in death rates between HWV and STO remains unexplained.

Risk of pneumonia in patients previously treated in hospital for pneumonia

Although elderly patients who are admitted to hospital for any disease have a higher risk of pneumonia subsequently, whether those treated in hospital for pneumonia are at even greater risk is unknown. Therefore we retrospectively assessed morbidity and mortality due to pneumonia after discharge in 573 consecutive patients admitted to hospital for pneumonia, gastrointestinal infection, renal infection, or erysipelas. Average follow-up was 34 months. The incidence rate for pneumonia was 5.45 times higher in the group of patients discharged after pneumonia than in the other groups combined (95% confidence interval 2.89-10.26; p less than 0.001), and this group also had more deaths due to pneumonia (p = 0.06). For patients 50 years or older Streptococcus pneumoniae is the main cause of pneumonia. Pneumococcal vaccination after hospital treatment for an episode of pneumonia might be a cost-effective means of preventing disease in this group.

Bacteraemic pneumococcal pneumonia: a continuously evolving disease

During an 8 year prospective study of community-acquired pneumonia (CAP) requiring hospitalisation we found that 47 of 1118 (4.2%) patients had Streptococcus pneumoniae bacteraemia. Females outnumbered males 27:20. The mean age was 63.4 years and 25% of our patients were admitted from a nursing home. A comparison with the 1071 other patients with CAP showed that patients with bacteraemic pneumococcal pneumonia (BPP) were more likely to be female and to have alcoholism, diabetes mellitus, and chronic obstructive pulmonary disease as co-morbidities. The mortality rate of 19% in BPP was not significantly lower than the 22% rate for the remaining patients with CAP. Four of the nine (44%) patients with BPP who died, did so within 24 h of admission, compared with 29 of 236 (12.3%) (P less than 0.02) who died of CAP. A notable clinical feature was the absence of cough in 19% while overall in only 66% was the cough productive. Most of the patients had a non-specific clinical presentation. Fifty-three per cent had an uncomplicated stay in hospital. We conclude that bacteraemic pneumococcal pneumonia is a continuously evolving disease and for the first time may now be more common in women.

A longitudinal study of class and subclass antibody response to pneumococcal vaccination in splenectomized individuals with special reference to patients with Hodgkin's disease

Antibody class and subclass response to pneumococcal vaccination was monitored in 173 splenectomized individuals. The distribution according to indication for splenectomy was Hodgkin's disease (HD; n = 41), non-Hodgkin lymphoma (NHL; n = 25), autoimmune hemolytic anemia or idiopathic thrombocytopenic purpura (n = 17), accidental splenectomy during abdominal surgery for malignant (AMA; n = 15) and benign (ABE; n = 42) disease and splenectomy due to splenic rupture caused by trauma (TRAUMA; n = 33). Pre-vaccination total IgG pneumococcal antibody values (i.e. against the whole antigen = the vaccine) in the NHL patients were lower than in the ABE and TRAUMA groups (p less than 0.05). The response to vaccination in HD and NHL patients did not differ from that in the other patient groups. Furthermore, pre-vaccination values did not differ between HD patients vaccinated before splenectomy and treatment and those vaccinated after, although the former group showed a better response to vaccination (p less than 0.05). HD and TRAUMA patients were followed by serial serum sampling. The antibody values declined to pre-treatment levels after 3 years but no differences either between HD and TRAUMA patients or between HD patients vaccinated before or after splenectomy and treatment were observed with regard to antibody decrease. It is concluded that pneumococcal antibody levels increased in all splenectomized patient groups following vaccination. The pattern of the antibody decline motivates revaccination studies in patients 2 yr post-immunization.

Diagnostic fiberoptic bronchoscopy and protected brush culture in patients with community-acquired pneumonia

A model for performing fiberoptic bronchoscopy as a supplement to noninvasive diagnostic methods, in patients with community-acquired pneumonia, was prospectively studied. Twenty-four patients underwent bronchoscopy, seven pilot patients and 17 of 277 (6 percent) consecutive patients with CAP. Indications for FOB were early therapy failure (less than or equal to 72h)(n = 7), late therapy failure (greater than 72h)(n = 11), or before start of antibiotic therapy in severely ill or immunocompromised patients (n = 6). Samples were obtained by aspiration of bronchial secretion and with a protected brush catheter from which quantitative cultures with a detection level of 10(4) colony forming units per ml were performed. Results concluded that FOB, with the use of quantitative PB-cultures, offered a safe and specific diagnostic tool, which on special indications, can be of great value in the management of patients with CAP.

Comparison of three methods for detection of pneumococcal antigen in sputum of patients with community-acquired pneumonia

In a prospective study of 249 patients with community-acquired pneumonia, three tests for the detection of pneumococcal antigen in sputum were compared: a coagglutination test for detecting capsular antigens (Cap-CoA), a sandwich enzyme immunoassay (PnC-EIA) and a coagglutination test (PnC-CoA), both the latter detecting the pneumococcal C-polysaccharide common to all pneumococcal types. Sixty-three patients had culture-positive pneumococcal pneumonia, 45 pneumonia caused by other bacteria and 141 pneumonia of viral or unknown etiology. The sensitivity of Cap-CoA (63%) and PnC-CoA (65%) was somewhat higher than that of PnC-EIA (49%), but not significantly so. The specificity was 96-98% for all three methods. Using PnC-CoA 66 patients with possible pneumococcal infection were detected, the diagnosis being verified by culture in 41. Using Cap-CoA 59 such patients were detected, the diagnosis being verified in 40, and using the PnC-EIA 47 such patients were detected, the diagnosis being verified in 31. Antigen was found almost as often in non-purulent as in purulent samples, and as often in washed as in non-washed purulent samples. However, antibiotic treatment before the sputum sample was obtained resulted in significantly lower sensitivity of both PnC-CoA and Cap-CoA. This study confirms the high sensitivity and specificity of methods for pneumococcal antigen detection in sputum. Since CoA is easier and quicker to perform, and cheaper than the EIA, either PnC-CoA or Cap-CoA would seem to be the technique of choice for detection of pneumococcal antigen, whereby all sputum samples, including non-purulent samples, can be used.

Clinical implications of positive blood cultures

Positive blood cultures can be classified according to their veracity (true-positive or false-positive culture), clinical severity (inconsequential or life threatening), place of origin (community acquired or nosocomial), source (primary or secondary), duration (transient, intermittent, or continuous), pattern of occurrence (single episode, persistent, or recurrent), or intensity (high or low grade). In general, however, positive blood cultures identify a patient population at high risk of death. In my studies, patients with positive blood cultures were 12 times more likely to die during hospitalization than patients without positive blood cultures. Many bacteremias and fungemias occur in complicated clinical settings, and it appears that only about one-half of the deaths among affected patients are due directly to infection. Hence, it is appropriate to speak of "crude mortality" and "attributable mortality." Among hospitalized patients, recent trends include rising incidences of Staphylococcus aureus and coagulase-negative staphylococcal and enterococcal bacteremias and a dramatic increase in the incidence of fungemias. The diagnostic and therapeutic implications of blood cultures positive for specific microorganisms continue to evolve and are the subject of a large and growing medical literature.

Bacteremic pneumococcal pneumonia in Stockholm, Sweden, in 1984

The case fatality rate among adults with community-acquired bacteremic pneumococcal pneumonia (Pnb) in Stockholm in 1984 was 11% (7/62), corresponding to an incidence of fatal Pnb of 0.5/100,000. This figure is low compared to data from the US and the UK, but corresponds well to our finding of a 7% mortality among patients with Pnb in a recent study covering part of the Stockholm population (2 hospitals).