Microbiological profile of community-acquired pneumonia in adults over the last 20 years

Effect of positive microbiological testing on antibiotic de-escalation and outcomes in community-acquired pneumonia: A propensity score analysis

OBJECTIVES

The usefulness of routine microbiological testing for rationalizing antibiotic use in hospitalized patients with community-acquired pneumonia (CAP) continues to be a subject of debate. We aim to determine the effect of positive microbiological testing on antimicrobial de-escalation and clinical outcomes in CAP.

METHODS

A retrospective analysis of a prospectively collected cohort of non-immunosuppressed adults hospitalized with CAP was performed. The primary study outcome was antimicrobial de-escalation. Secondary outcomes included 30-day case-fatality rate, adverse events, and CAP recurrence. Adjustment for confounders, was performed by inverse probability weighting propensity score (IPW-PS), logistic regression and cause-specific Cox model.

RESULTS

Of 3677 patients with CAP, 1924 (52.3%) had any positive microbiological test. Antimicrobial de-escalation was performed in 648/1924 (33.7%) of patients with positive microbiological testing and in 179/1753 (10.2%) of those with non positive results. When propensity score was entered into the multivariate analysis, positive microbiological testing (Adjusted Odds Ratio [AOR] 2.59 (1.96 - 3.41) and clinical stability at day 3 (AOR 1.87; 1.45 - 2.10) were two of the main factors independently associated with antimicrobial de-escalation. After applying an adjusted cause-specific Cox model, antimicrobial de-escalation was not associated with a higher 30-day case-fatality rate (Adjusted Hazard Ratio [AHR] 0.44; 0.14 - 1.43), higher frequency of adverse events (AHR 0.77; 0.53 - 1.12) or CAP recurrence (AHR 0.77; 0.45 - 1.28).

CONCLUSIONS

Antimicrobial de-escalation was more often performed in hospitalized patients with CAP who had positive microbiological tests than in those with non positive results, and it did not adversely affect relevant clinical outcomes.

Absence of Association between Previous Mycoplasma pneumoniae Infection and Subsequent Myasthenia Gravis: A Nationwide Population-Based Matched Cohort Study

Mycoplasma pneumoniae (M. pneumoniae) is not only one of the most common pathogenic bacteria for respiratory infection but also a trigger for many autoimmune diseases. Its infection process shared many similarities with the pathogenesis of myasthenia gravis (MG) at cellular and cytokine levels. Recent case reports demonstrated patients present with MG after M. pneumoniae infection. However, no epidemiological studies ever looked into the association between the two. Our study aimed to investigate the relationship between M. pneumoniae infection and subsequent development of MG. In this population-based retrospective cohort study, the risk of MG was analyzed in patients who were newly diagnosed with M. pneumoniae infection between 2000 and 2013. A total of 2428 M. pneumoniae patients were included and matched with the non-M. pneumoniae control cohort at a 1:4 ratio by age, sex, and index date. Cox proportional hazards regression analysis was applied to analyze the risk of MG development after adjusting for sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The incidence rates of MG in the non-M. pneumoniae and M. pneumoniae cohorts were 0.96 and 1.97 per 10,000 person-years, respectively. Another case-control study of patients with MG (n = 515) was conducted to analyze the impact of M. pneumoniae on MG occurrence as a sensitivity analysis. The analysis yielded consistent absence of a link between M. pneumoniae and MG. Although previous studies have reported that M. pneumoniae infection and MG may share associated immunologic pathways, we found no statistical significance between M. pneumoniae infection and subsequent development of MG in this study.

Vaccine Composition Formulated with a Novel Lactobacillus-Derived Exopolysaccharides Adjuvant Provided High Protection against Staphylococcus aureus

A vaccine that effectively targets methicillin-resistant Staphylococcus aureus (MRSA) is urgently needed, and has been the focus of studies by numerous research groups, but with limited success to date. Recently, our team found that exopolysaccharides derived from probiotic Lactobacilluscasei strain WXD030 as an adjuvant-formulated OVA could upregulate IFN-γ and IL-17 expression in CD4⁺ T cells. In this study, we developed a vaccine (termed rMntC-EPS) composed of S. aureus antigen MntC and Lactobacillus casei exopolysaccharides, which conferred high levels of protection against S. aureus infection. Methods: Six–eight-week-old female mice were vaccinated with purified rMntC-EPS30. The immune protection function of rMntC-EPS30 was assessed by the protective effect of rMntC-EPS30 to S. aureus-induced pulmonary and cutaneous infection in mice, bacterial loads and H&E in injury site, and ELISA for inflammation-related cytokines. The protective mechanism of rMntC-EPS30 was assessed by ELISA for IgG in serum, cytokines in the spleen and lungs of vaccinated mice. In addition, flow cytometry was used for analyzing cellular immune response induced by rMntC-EPS30. For confirmation of our findings, three kinds of mice were used in this study: IL-17A knockout mice, IFN-γ knockout mice and TCRγ/δ knockout mice. Results: rMntC-EPS30 conferred up to 90% protection against S. aureus pulmonary infection and significantly reduced the abscess size in the S. aureus cutaneous model, with clearance of the pathogen. The rMntC-EPS vaccine could induce superior humoral immunity as well as significantly increase IL-17A and IFN-γ production. In addition, we found that rMntC-EPS vaccination induced robust Th 17/γδ T 17 primary and recall responses. Interestingly, this protective effect was distinctly reduced in the IL-17A knockout mice but not in IFN-γ knockout mice. Moreover, in TCRγ/δ knockout mice, rMntC-EPS vaccination neither increased IL-17A secretion nor provided effective protection against S. aureus infection. Conclusions: These data demonstrated that the rMntC formulated with a novel Lactobacillus-derived Exopolysaccharides adjuvant provided high protection against Staphylococcus aureus. The rMntC-EPS vaccine induced γδ T cells and IL-17A might play substantial roles in anti-S. aureus immunity. Our findings provided direct evidence that rMntC-EPS vaccine is a promising candidate for future clinical application against S. aureus-induced pulmonary and cutaneous infection.

Community acquired pneumonia among adult patients at an Egyptian university hospital: bacterial etiology, susceptibility profile and evaluation of the response to initial empiric antibiotic therapy

Background

Effective empirical antibiotic therapy for community acquired pneumonia (CAP), based on frequently updated data about the pattern of bacterial distribution and their antimicrobial susceptibilities, is mandatory.

Aim

To identify the bacterial etiology of CAP in adults and their antibiotic susceptibility patterns and to evaluate the response to initial empirical antibiotic therapy in an Egyptian university hospital.

Settings and design

A cross-sectional hospital-based study.

Patients and methods

CAP cases were selected by systemic random sampling from those admitted to the chest department. All were evaluated at admission and 4 days after starting empiric therapy. Typical bacteria were isolated, identified and tested for their antibiotic susceptibility. An indirect IF assay was used to diagnose atypical bacteria. Clinical response to initial empiric antibiotic therapy was clinically, laboratory and radiologically evaluated.

Results

Two hundred and seventy CAP patients were included. Bacteria represented 50.4% of them. Klebsiella pneumoniae was the most prevalent bacterium (10.37%) followed by Streptococcus pneumoniae and P. aeruginosa (7.78% each). Overall, 76.2% of isolates showed a multidrug resistant phenotype: 82.61% (19/23) S. pneumoniae, 89.66 % (26/29) K. pneumoniae, 65.22% (15/23) Pseudomonas aeruginosa, 87.50% (7/8) Escherichia coli and 81.25 % (13/16) Staphylococcus aureus. Broad spectrum β-lactams, especially carbapenems, and moxifloxacin showed in vitro efficacy on most of the tested isolates. Forty-three cases (15.9%) were nonresponders, 37 (86%) of them showed bacterial etiology. The highest rate of nonresponsiveness (30.43%) was observed in cases receiving antipseudomonal/antipneumococcal β-lactam plus a fluoroquinolone for suspected P. aeruginosa infection.

Conclusion

Multidrug resistance in bacteria causing CAP and high frequency of isolation of hospital pathogens are prominent features of this study. Azithromycin containing regimens were associated with the lowest rates of nonresponsiveness. Development and implementation of an antibiotic stewardship program are highly recommended for CAP management.

Factors influencing severity of community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality in India. There is a need to understand the risk factors associated with severity of CAP in our population. This study was part of the international global initiative for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia study to evaluate MRSA.

METHODS

A total of 100 consecutive cases of pneumonia admitted to the Department of Pulmonary Medicine in a tertiary care hospital were recruited in the study during March-July 2015. The severity of pneumonia was assessed based on the CURB-65 score. Individuals with pneumonia and CURB-65 score >2 were compared with subjects with CURB-65 score ≤2. Individuals were also evaluated for the causative organism and its resistance pattern with specific reference to the presence of MRSA.

RESULTS

Mean age of patients was 54.03 years, 66% were men. Patients were managed either in the intensive care unit (42%) or wards/high dependency unit (58%), 22% needed noninvasive ventilation and 18% needed mechanical ventilation within 24 h of admission. On multivariate analysis, prior respiratory infection (within last 1 year), obesity (body mass index >30), and alcoholism, old age (>60 years) were independently associated risk factors for severe pneumonia. There were no cases of MRSA. In 34% of cases, organisms could be identified. Most common organisms were Klebsiella (8%), influenza (8%), and Pseudomonas (5%).

CONCLUSION

Prior respiratory infection, obesity, alcoholism, and old age (>60 years) were observed to be important risk factors for severe CAP. Prospective studies should evaluate effect of weight reduction and cessation of alcohol consumption on recurrences of pneumonia in this population and on the severity of pneumonia.

Systematic review of respiratory viral pathogens identified in adults with community-acquired pneumonia in Europe

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Respiratory viruses are potentially implicated in one quarter to one-third of adult cases of community-acquired pneumonia.

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In such cases influenza is the most frequently detected viral pathogen.

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Failure to test for respiratory viruses in hospitalised patients may lead to missed opportunities for early therapeutic intervention.

Community-acquired pneumonia (CAP) is an important respiratory disease and the fifth leading cause of mortality in Europe. The development of molecular diagnostic tests has highlighted the contributions of respiratory viruses to the aetiology of CAP, suggesting the incidence of viral pneumonia may have been previously underestimated. We performed a systematic review and meta-analysis to describe the overall identification of respiratory viruses in adult patients with CAP in Europe, following PRISMA guidelines (PROSPERO; CRD42016037233). We searched EMBASE, MEDLINE, CINAHL, WHOLIS, COCHRANE library and grey literature sources for relevant studies, and screened these against protocol eligibility criteria. Two researchers performed data extraction and risk of bias assessments, independently, using a piloted form. Results were synthesised narratively, and random effects meta-analyses performed to calculate pooled estimates of effect; heterogeneity was quantified using I². Twenty-eight studies met inclusion criteria of which 21 were included in the primary meta-analysis. The pooled proportion of patients with identified respiratory viruses was 22.0% (95% CI: 18.0%–27.0%), rising to 29.0% (25.0%–34.0%) in studies where polymerase chain reaction (PCR) diagnostics were performed. Influenza virus was the most frequently detected virus in 9% (7%–12%) of adults with CAP. Respiratory viruses make a substantial contribution to the aetiology of CAP in adult patients in Europe; one or more respiratory viruses are detected in about one quarter of all cases.

In Vivo Pharmacodynamic Evaluation of Omadacycline (PTK 0796) against Streptococcus pneumoniae in the Murine Pneumonia Model

Omadacycline is a novel aminomethylcycline antibiotic in clinical development for community-acquired bacterial pneumonia (CABP). We used a neutropenic murine pneumonia infection model to characterize the in vivo pharmacodynamic activity of omadacycline against Streptococcus pneumoniae Four strains with various phenotypic resistances to other antimicrobials, including tetracyclines, were utilized. Drug concentration measurements were performed in the plasma and epithelial lining fluid (ELF) after administration of 0.5, 2, 8, and 32 mg/kg. Pharmacokinetic parameters were calculated using a noncompartmental model and were linear over the dose range. Penetration into ELF ranged from 72 to 102%. Omadacycline demonstrated net cidal activity in relation to the initial burden against all four strains. The pharmacokinetic/pharmacodynamic index AUC/MIC correlated well with efficacy (R² = 0.74). The plasma 24-h static dose AUC/MIC values were 16 to 20 (24-h ELF AUC/MIC of 14 to 18). A 1-log₁₀ kill was achieved at 24-h plasma AUC/MIC values of 6.1 to 180 (24-h ELF AUC/MIC values 6.0 to 200). A 2-log₁₀ kill was achieved at 24-h plasma AUC/MIC values of 19 to 56 (24-h ELF AUC/MIC of 17 to 47). The targets identified in this study in combination with in vitro potency and favorable human pharmacokinetics make omadacycline an attractive candidate for further development and study in patients with CABP.

Multiplex Urinary Antigen Detection for 13 Streptococcus pneumoniae Serotypes Improves Diagnosis of Pneumococcal Pneumonia in South African HIV-Infected Adults

A serotype-specific urinary antigen detection (UAD) assay for 13 serotypes included in the pneumococcal conjugate vaccine (PCV13) was recently reported as a useful diagnostic tool for pneumococcal pneumonia. We aimed to assess the diagnostic accuracy of the UAD in HIV-infected South African adults. Urine specimens from a well-defined cohort of HIV-infected South African adults with pneumonia were evaluated retrospectively in the UAD assay. Pneumonia was considered pneumococcal if either sputum Gram stain, sputum culture, blood culture, or the immunochromatographic (ICT) BinaxNow S. pneumoniae test (composite diagnostic) was positive. Among 235 enrolled pneumonia patients, the UAD assay was more frequently positive (104 [44.3%]) than the composite diagnostic (71 [30.2%]; P < 0.001) and increased the pneumococcal etiology from 30.2% by an additional 22.6% to 52.8%. The UAD assay detected more pneumococcal etiologies (45.0%) than the serotype-independent ICT (23.4%, P < 0.001). UAD identified 6/7 patients with PCV13 serotype bacteremia without misclassification of bacteremia episodes due to non-PCV13 serotypes. UAD was positive for 5.1% of asymptomatic HIV-infected persons, with higher rates among those with nasopharyngeal carriage. Concordance between serotypes identified by UAD and by Quellung reaction and PCR serotyping was 70/86 (81.4%). UAD identified the dominant serotype in multiple serotype carriage. This study confirms the utility of the UAD assay for HIV-infected adults comparing favorably with other diagnostic tests. A highly valent UAD may become a new standard for detection of pneumococcal pneumonia in adults. Prior to PCV introduction, at least 53% of pneumonia cases were due to pneumococci in HIV-infected South African adults.

Community-associated Staphylococcus aureus pneumonia among Greek children: epidemiology, molecular characteristics, treatment, and outcome

Staphylococcus aureus is an infrequent cause of community-associated (CA-SA) pneumonia in children. The aim of this study was to evaluate the clinical, epidemiological, microbiological, and molecular characteristics of CA-SA pneumonia among children hospitalized in two large tertiary care referral centers during an 8-year period. Cases of CA-SA pneumonia admitted between 2007 and 2014 were retrospectively examined through medical record review. Molecular investigation was performed for available strains; mecA, Panton-Valentine leukocidin (PVL) (lukS-lukF-PV), and fibronectin binding protein A (fnbA) genes were detected by polymerase chain reaction (PCR). Clones were assigned by agr groups, pulsed-field gel electrophoresis (PFGE), SCCmec, and multilocus sequencing typing (MLST). In total, 41 cases were recorded (boys, 61 %), with a median age of 4.3 months (range, 1-175). Methicillin-resistant S. aureus (MRSA) accounted for 31 cases (75.6 %). Complications included empyema (25/41, 61 %), pneumatoceles (7/41, 17 %), and lung abscess (1/41, 2.5 %). Intensive care unit (ICU) admission was required in 58.5 %. Two deaths occurred (4.9 %). Definitive therapy was based on vancomycin with or without other antibiotics (55.9 %), followed by clindamycin and linezolid (26.5 % each). All isolates were susceptible to vancomycin (MIC90 2 mg/L, range 1-2), teicoplanin, and linezolid, whereas 26.8 % were resistant to clindamycin. Among the 25 studied strains, 20 were mecA-positive (MRSA), carrying also the fnbA gene. Of these, 90 % belonged to the ST80-IV/agr3/PVL-positive clone. Methicillin-susceptible S. aureus (MSSA) strains showed polyclonality, 3/5 were PVL-positive, and 3/5 were fnbA-positive. MRSA and particularly the ST80-IV clone predominated among staphylococcal pneumonia cases in children. Treatment provided was effective in all but two patients, despite the relatively high minimum inhibitory concentration (MIC) of vancomycin and a high resistance to clindamycin.

Prevalence, genotyping and macrolide resistance of Mycoplasma pneumoniae among isolates of patients with respiratory tract infections, Central Slovenia, 2006 to 2014

In this retrospective study we employed real-time polymerase chain reaction (PCR) to analyse the occurrence of Mycoplasma pneumoniae among upper and lower respiratory tract infections (RTI) in the Central Region of Slovenia between January 2006 and December 2014. We also used a culture and pyrosequencing approach to genotype strains and infer their potential macrolide resistance. Of a total 9,431 tested samples from in- and out-patient with RTI, 1,255 (13%) were found to be positive by M. pneumoniae PCR. The proportion of positive samples was 19% (947/5,092)among children (≤16 years-old) and 7% (308/4,339) among adults (>16 years-old). Overall, among those PCR tested, the highest proportions of M. pneumonia infections during the study period were observed in 2010 and 2014. In these two years, 18% (218/1,237) and 25% (721/2,844) of samples were positive respectively,indicating epidemic periods. From the 1,255 M. pneumoniae PCR-positive samples, 783 (614 from paediatric and 169 from adult patients) were successfully cultured. Of these, 40% (312/783) were constituted of strains belonging to the P1 type II genomic group, while 60% (469/783) contained strains of the P1 type I group. Two isolates comprised both P1 type Iand II strains. Results of a genotype analysis by year,showed that the dominant M. pneumoniae P1 type during the 2010 epidemic was P1 type II (82% of isolates;81/99), which was replaced by P1 type I in the 2014 epidemic (75%; 384/510). This observation could indicate that the two epidemics may have been driven by a type shift phenomenon, although both types remained present in the studied population during the assessed period of time. Only 1% of strains (7/783) were found to harbour an A2063G mutation in the 23S rRNA gene,which confers macrolide resistance, suggesting that the occurrence of M. pneumoniae macrolide resistance still seems to be sporadic in our geographic area.

Community-acquired pneumonia

Community-acquired pneumonia causes great mortality and morbidity and high costs worldwide. Empirical selection of antibiotic treatment is the cornerstone of management of patients with pneumonia. To reduce the misuse of antibiotics, antibiotic resistance, and side-effects, an empirical, effective, and individualised antibiotic treatment is needed. Follow-up after the start of antibiotic treatment is also important, and management should include early shifts to oral antibiotics, stewardship according to the microbiological results, and short-duration antibiotic treatment that accounts for the clinical stability criteria. New approaches for fast clinical (lung ultrasound) and microbiological (molecular biology) diagnoses are promising. Community-acquired pneumonia is associated with early and late mortality and increased rates of cardiovascular events. Studies are needed that focus on the long-term management of pneumonia.

Development of a Multilocus Sequence Typing Scheme for Molecular Typing of Mycoplasma pneumoniae

Mycoplasma pneumoniae is a major human respiratory pathogen causing both upper and lower respiratory disease in humans of all ages, and it can also result in other serious extrapulmonary sequelae. A multilocus sequence typing (MLST) scheme for M. pneumoniae was developed based on the sequences of eight housekeeping genes (ppa, pgm, gyrB, gmk, glyA, atpA, arcC, and adk) and applied to 55 M. pneumoniae clinical isolates and the two type strains M129 and FH. A total of 12 sequence types (STs) resulted for 57 M. pneumoniae isolates tested, with a discriminatory index of 0.21 STs per isolate. The MLST loci used in this scheme were shown to be stable in 10 strains following 10 sequential subculture passages. Phylogenetic analysis of concatenated sequences of the eight loci indicated two distinct genetic clusters that were directly linked to multilocus variable-number tandem repeat analysis (MLVA) type. Genetic MLST clustering was confirmed by genomic sequence analysis, indicating that the MLST scheme developed in this study is representative of the genome. Furthermore, this MLST scheme was shown to be more discriminatory than both MLVA and P1 typing for the M. pneumoniae isolates examined, providing a method for further and more detailed analysis of observed epidemic peaks of M. pneumoniae infection. This scheme is supported by a public Web-based database (http://pubmlst.org/mpneumoniae).

Changing bacteriological profile and mortality trends in community acquired pneumonia

There are very few and conflicting Indian data regarding the bacteriological etiology of community acquired pneumonia (CAP). Adding to this agony, there is no credible data from the eastern part of India. This is a cross-sectional study and descriptive in nature over a period of 1-year. Of the 464 cases of the study population, we could isolate aerobic bacteria in 149 patients (32.1%). Streptococcus pneumoniae has been identified as the most common organism causing CAP (68/149). Gram-negative bacilli (GNB) as a group exceeded marginally over S. pneumoniae (69/149). Among GNB, Pseudomonas aeruginosa was the most common organism (31/69), followed by Klebsiella pneumoniae (29/69). Staphylococcus aureus was identified in (12/149) cases. Co-amoxyclav is still the most sensitive drug for S. pneumoniae. P. aeruginosa was most sensitive to imipenam followed by piperacillin-tazobactam.

Predicting risk of drug-resistant organisms in pneumonia: moving beyond the HCAP model

BACKGROUND

Clinical management of community-acquired pneumonia (CAP) is increasingly complicated by antibiotic resistance. CAP due to pathogens resistant to guideline-recommended drugs (CAP-DRP) has increased. 2005 ATS/IDSA guidelines introduced a new category, healthcare-associated pneumonia (HCAP), and recommend extended-spectrum antibiotic treatment for patients meeting HCAP criteria. However, the predictive value of the HCAP model is limited and data suggest that outcomes are not improved using HCAP guideline-concordant therapy. Better methods to predict risk of CAP-DRP are needed.

METHODS

We reviewed currently published literature on the performance status of HCAP as a predictive tool and studies describing additional risk factors for CAP-DRP. We also summarize the performance characteristics of the currently published alternative clinical prediction scores and compare them to that of the HCAP model.

RESULTS

In addition to the five risk factors incorporated in HCAP, at least 13 other factors have been identified. The independent predictive value of any single factor is low, but accumulating factors results in increased risk of CAP-DRP. The performance characteristics of 9 clinical prediction scores are reviewed. Nearly all of the scores outperformed HCAP in their study populations. However, no single model has yet demonstrated adequate specificity to minimize unnecessary antibiotic use, while retaining sufficient sensitivity to prevent inadequate initial empiric antibiotic therapy when validated across a wide range of CAP-DRP prevalence.

CONCLUSIONS

Additional development and validation of prediction scores based upon more refined risk factors for CAP-DRP is needed. Once an accurate, adequately validated prediction score is available, an interventional trial will be needed to determine clinical impact.

Patient Outcomes on Day 4 of Intravenous Antibiotic Therapy in Non-Intensive Care Unit Hospitalized Adults With Community-Acquired Bacterial Pneumonia

BACKGROUND

Community-acquired bacterial pneumonia (CABP) is a leading cause of morbidity and mortality especially in hospitalized patients. In place of clinical end points traditionally used to evaluate antimicrobial efficacy for its treatment, Food and Drug Administration guidelines now require all registration trials to assess clinical response at day 4. The primary objective of this study was to assess health outcomes (length of stay [LOS] and hospital charges) between responders and nonresponders at this time point.

METHODS

The Premier database was used to identify adult patients from 4 participating hospitals with a principal diagnosis of CABP (International Classification of Diseases, Ninth Revision, Clinical Modification, codes 481, 482.0, 483.8, 484.3, 484.5, 485, 486, or 487.0) hospitalized between July 1, 2010, and June 30, 2011. Only non-intensive care unit patients with hospital stays exceeding 2 days and receiving intravenous antibiotic agents within 24 hours of admission were included. After institutional review board approvals, a retrospective chart review extracted data for patient demographics, clinical efficacy variables at day 4, LOS, and total hospital charges. Data analysis included multivariable gamma regression models to control for patient demographics and clinical differences between responders and nonresponders.

RESULTS

A total of 666 patients met study the criteria. Mean (SD) age was 70.7 (17.9) years, and 42.5% were males. Among these patients, 277 (41.6%) achieved clinical response by day 4 of initial antibiotic therapy. The unadjusted mean (SD) LOS was 6.3 (2.8) days for responders and 7.4 (5.6) days for nonresponders (P = 0.0009). Respective unadjusted total hospital charges were $22,827 (SD, $17,724) and $26,403 ($36,882) (P = 0.0031). Adjusted for demographics and clinical factors, nonresponders compared with responders had an increased LOS of 0.9 days (8.4 vs 7.5 days; P = 0.0008), resulting in associated charges of approximately $2500 ($34,139 vs $36,629; P = 0.0768).

CONCLUSIONS

In this real-world chart study, less than half of hospitalized patients with CABP achieved clinical response at day 4 of initial intravenous antibiotic therapy. The observed clinical response was associated with a significantly shorter hospital stay and trended toward lower total hospital charges. These findings corroborate the Food and Drug Administration guidance for assessing antimicrobial therapy at day 4 because responder is associated with improved health outcomes.

Efficacy and safety of moxifloxacin in community acquired pneumonia: a prospective, multicenter, observational study (CAPRIVI)

Background

Community acquired pneumonia (CAP) is a major cause of morbidity, hospitalization, and mortality worldwide. Management of CAP for many patients requires rapid initiation of empirical antibiotic treatment, based on the spectrum of activity of available antimicrobial agents and evidence on local antibiotic resistance. Few data exist on the severity profile and treatment of hospitalized CAP patients in Eastern and Central Europe and the Middle East, in particular on use of moxifloxacin (Avelox®), which is approved in these regions.

Methods

CAPRIVI (Community Acquired Pneumonia: tReatment wIth AVelox® in hospItalized patients) was a prospective observational study in 12 countries: Croatia, France, Hungary, Kazakhstan, Jordan, Kyrgyzstan, Lebanon, Republic of Moldova, Romania, Russia, Ukraine, and Macedonia. Patients aged >18 years were treated with moxifloxacin 400 mg daily following hospitalization with a CAP diagnosis. In addition to efficacy and safety outcomes, data were collected on patient history and disease severity measured by CRB-65 score.

Results

2733 patients were enrolled. A low severity index (i.e., CRB-65 score <2) was reported in 87.5% of CAP patients assessed (n = 1847), an unexpectedly high proportion for hospitalized patients. Moxifloxacin administered for a mean of 10.0 days (range: 2.0 to 39.0 days) was highly effective: 96.7% of patients in the efficacy population (n = 2152) improved and 93.2% were cured of infection during the study. Severity of infection changed from “moderate” or “severe” in 91.8% of patients at baseline to “no infection” or “mild” in 95.5% at last visit. In the safety population (n = 2595), 127 (4.9%) patients had treatment-emergent adverse events (TEAEs) and 40 (1.54%) patients had serious TEAEs; none of these 40 patients died. The safety results were consistent with the known profile of moxifloxacin.

Conclusions

The efficacy and safety profiles of moxifloxacin at the recommended dose of 400 mg daily are characterized in this large observational study of hospitalized CAP patients from Eastern and Central Europe and the Middle East. The high response rate in this study, which included patients with a range of disease severities, suggests that treatment with broader-spectrum drugs such as moxifloxacin is appropriate for patients with CAP who are managed in hospital.

Trial registration

ClinicalTrials.gov identifier: NCT00987792

Impact of a clinical decision support system on pharmacy clinical interventions, documentation efforts, and costs

Health care organizations are turning to electronic clinical decision support systems (CDSSs) to increase quality of patient care and promote a safer environment. A CDSS is a promising approach to the aggregation and use of patient data to identify patients who would most benefit from interventions by pharmacy clinicians. However, there are limited published reports describing the impact of CDSS on clinical pharmacy measures. In February 2011, Good Shepherd Medical Center, a 425-bed acute care community hospital in East Texas, implemented a CDSS (TheraDoc clinical surveillance system). Prior to CDSS implementation, clinicians struggled with obtaining and documenting the data needed to support clinical initiatives. The value of having both clinical and staff pharmacists utilizing the CDSS has improved communication and knowledge among staff and improved relationships with medical staff, nursing, and case management. The department of pharmacy increased its clinical interventions from an average of 1,986 per month to 4,065 per month; this represents a 105% increase in the number of interventions. The annual estimated cost savings after CDSS implementation is $2,999,508, representing a 96% increase per year and translating into a $1,469,907 annual return on investment.

Pathogenesis of Staphylococcus aureus necrotizing pneumonia: the role of PVL and an influenza coinfection

Only recently necrotizing pneumonia was defined as a specific disease entity that is caused by a Panton-Valentine leukocidin (PVL)-producing Staphylococcus aureus strain and is frequently preceded by an influenza infection. Necrotizing pneumonia is characterized by a sudden onset and rapid worsening of symptoms, leukopenia, airway hemorrhages, severe respiratory failure and a high mortality rate. Despite clear epidemiological data, the function of PVL in necrotizing pneumonia has been controversially discussed due to conflicting results from different disease models. Furthermore, there are many proposed mechanisms how a viral infection could facilitate and interact with a bacterial superinfection. In this review, we summarize current data from 43 clinical cases and results from various infection models on necrotizing pneumonia. We discuss the contribution of S. aureus PVL and a preceding influenza infection and present a concept of the pathogenesis of necrotizing pneumonia.

Etiology and outcome of severe community acquired pneumonia in immunocompetent adults

BACKGROUND

Community Acquired Pneumonia (CAP) is a commonly encountered disease, one third of which is Severe Community Acquired Pneumonia (SCAP) that can be potentially fatal. There is a paucity of data on etiology and outcome of patients with SCAP in South Asian Population.

METHODS

A retrospective cross-sectional study was conducted from March 2002 till December 2008 on patients of 16 years and above who were admitted with the diagnosis of SCAP in accordance to the criteria of American Thoracic Society Guidelines (2001). The patients underwent clinical and diagnostic evaluations to detect the severity of illness as well as the etiology and other risk factors influencing the eventual outcome of SCAP.

RESULTS

A total of 189 patients were included in the study. The mean age was 60 ± 18.0 years and 110 (58%) patients were males. The most common isolated pathogens were Staphylococcus aureus (15 patients), Streptococcus pneumoniae (14 patients) and Pseudomonas aeruginosa (9 patients). The highest mortality was seen in patients with Pseudomonas aeruginosa (89%) and Staphylococcus aureus (53%). Overall mortality rate was 51%. On univariate analysis, septic shock (p <0.001), prior antibiotic use (p = 0.04), blood urea nitrogen > 30 mg/dl (p = 0.03), hematocrit < 30% (p = 0.03) and Acute Physiology and Chronic Health Evaluation (APACHE) II score > 20 (p < 0.001) were significantly different between the patients who survived as compared to those who did not. On multivariate analysis, septic shock (p <0.001, OR: 4.70; 95% CI= 2.49-8.87) was found to be independently associated with mortality.

CONCLUSION

The microbes causing SCAP in our study are different from the usual spectrum. Staphylococcus aureus and Pseudomonas aeruginosa were the common causative pathogens and associated with high mortality. It is important to establish clinical guidelines for managing SCAP according to the etiologic organisms in our setting.

Low utilisation of diagnostic microbiology for community acquired pneumonia in regional Victoria

Aims

Diagnostic microbiology for community acquired pneumonia (CAP) provides useful information for patient management, infection control and epidemiological surveillance. Newer techniques enhance that information and the time interval for obtaining results. An audit of diagnostic microbiology utilisation, microbiological aetiology, and influence of results on prescribing practices in CAP in a regional Australian hospital setting was performed.

Methods

Clinical, microbiological and outcome data were collected by medical record review of patients discharged from Ballarat Hospital with a diagnosis of CAP over a 12 month period.

Results

Of 184 identified CAP episodes, 47 (25.5%) had no diagnostic microbiology performed. Respiratory virus polymerase chain reaction (PCR) was rarely performed (2.7% of all episodes). Acute serology was frequently requested, however paired acute and convalescent serology was infrequently performed (5/75 testing episodes; 6.7%). CAP severity was not correlated with microbiological investigation intensity. The most common pathogens identified were Streptococcus pneumoniae and Mycoplasma pneumoniae (5.4% and 2.2%, respectively). Diagnostic testing appeared to rarely influence antimicrobial prescribing.

Conclusions

In this setting, diagnostic microbiological tests such as respiratory virus PCR and urinary antigen tests are under-utilised. In contrast, sputum and serological investigations are commonly requested, however rarely influence practice. Interventions to facilitate efficient usage of diagnostic microbiology are required.

Infectious diseases causing diffuse alveolar hemorrhage in immunocompetent patients: a state-of-the-art review

Diffuse alveolar hemorrhage (DAH) represents a syndrome that can complicate many clinical conditions and may be life-threatening, requiring prompt treatment. It is recognized by the signs of acute- or subacute-onset cough, hemoptysis, diffuse radiographic pulmonary infiltrates, anemia, and hypoxemic respiratory distress. DAH is characterized by the accumulation of intra-alveolar red blood cells originating most frequently from the alveolar capillaries. It must be distinguished from localized pulmonary hemorrhage, which is most commonly due to chronic bronchitis, bronchiectasis, tumor, or localized infection. Hemoptysis, the major sign of DAH, may develop suddenly or over a period of days to weeks; this sign may also be initially absent, in which case diagnostic suspicion is established after sequential bronchoalveolar lavage reveals worsening red blood cell counts. The causes of DAH can be divided into infectious and noninfectious, the latter of which may affect immunocompetent or immunodeficient patients. Pulmonary infections are rarely reported in association with DAH, but they should be considered in the diagnostic workup because of the obvious therapeutic implications. In immunocompromised patients, the main infectious diseases that cause DAH are cytomegalovirus, adenovirus, invasive aspergillosis, Mycoplasma, Legionella, and Strongyloides. In immunocompetent patients, the infectious diseases that most frequently cause DAH are influenza A (H1N1), dengue, leptospirosis, malaria, and Staphylococcus aureus infection. Based on a search of the PubMed and Scopus databases, we review the infectious diseases that may cause DAH in immunocompetent patients.

Vaccination of risk groups in England using the 13 valent pneumococcal conjugate vaccine: economic analysis

OBJECTIVE

To estimate the cost effectiveness of vaccinating people with high risk conditions against invasive pneumococcal disease using the 13 valent pneumococcal conjugate vaccine.

DESIGN

Economic evaluation using a cohort model from the perspective of healthcare providers.

SETTING

England.

PARTICIPANTS

People aged 2 years and older at increased risk of invasive pneumococcal disease due to chronic kidney disease; splenic dysfunction; HIV infection; a compromised immune system; chronic heart, liver, or respiratory disease; or diabetes.

MAIN OUTCOME MEASURES

Costs, gains in life years and quality adjusted life years (QALYs), and incremental cost effectiveness ratios.

RESULTS

Increasing indirect protection resulting from the vaccination programme of infants using the 13 valent pneumococcal conjugate vaccine means that the burden of disease preventable by targeting high risk groups will diminish in time. Under base case assumptions--that is, no overall impact on non bacteraemic pneumonia in high risk groups and assuming the high risk vaccination programme would be launched two to three years after the infant programme--the incremental cost effectiveness ratio was estimated to be more than £30,000 (€37,216; $48,210) per QALY gained for most risk groups. If, however, the vaccine does not offer protection against non-bacteraemic pneumococcal pneumonia or the vaccine was introduced concomitantly with the infant 13 valent pneumococcal conjugate vaccination programme then vaccinating high risk people would (more) likely be cost effective. Sensitivity analyses showed that the cost effectiveness was particularly sensitive to assumed herd benefits and vaccine efficacy estimates.

CONCLUSION

Under base case assumptions it is unlikely that a pneumococcal vaccination programme aimed at risk groups could be considered cost effective. Uncertainty could be substantially reduced by establishing the effectiveness of the 13 valent pneumococcal conjugate vaccine against non-bacteraemic pneumococcal pneumonia, particularly in at risk groups.

Role of gamma-delta T cells in host response against Staphylococcus aureus-induced pneumonia

Background

Staphylococcus aureus is the major cause of hospital-acquired and community-acquired pneumonia. Host defense to S.aureus infection is largely mediated by the innate immune system. γδ T cells play an important role in innate immunity to many infectious diseases. However, less is known about the role of these cells during S.aureus-induced pneumonia. In this study, we examined the response and the role of γδ T cells to pulmonary S.aureus infection.

Results

Mice infected with S. aureus intranasally showed rapid γδ T cells accumulation in the lung. Deficiency of γδ T cells led to attenuated bacterial clearance and less tissue damage in lung compared with WT mice. Moreover, TCR-δ^−/− mice exhibited impaired neutrophil recruitment and reduced cytokine production at the site of infection. The γδ T cells in response to pulmonary S. aureus infection mainly secreted IL-17 and γδ T cells deficiency reduced IL-17 production, which might regulate the production of neutrophil-inducing cytokine/chemokine in the S. aureus-infected lungs.

Conclusions

Accumulation of γδ T cells in the lungs to S. aureus infection is beneficial for bacteria clearance and also contributes to the tissue damage. These cells were the primary source of IL-17, which might influence the recruitment of neutrophils at the early stage of infection.

Community-acquired necrotizing pneumonia due to methicillin-sensitive Staphylococcus aureus secreting Panton-Valentine leukocidin: a review of case reports

BACKGROUND

Community-acquired necrotizing pneumonia caused by Panton-Valentine leukocidin (PVL)-secreting Staphylococcus aureus is a highly lethal infection that mainly affects healthy children and young adults. Both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) may carry the PVL-phage, but the majority of publications relate to community-associated methicillin-resistant S. aureus (CA-MRSA) or mixed patient groups. This study focuses on necrotizing pneumonia due to methicillin-sensitive S. aureus strains, with the purpose to determine factors associated with outcome.

METHODS

We report a patient with PVL secreting MSSA necrotizing pneumonia and performed a systematic review of similar case in the literature. We analyzed factors associated with outcome.

RESULTS

A total of 32 patient descriptions were retained for analysis. Septic shock (p = 0.007), influenza-like prodrome (p = 0.02), and the absence of a previous skin and soft-tissue infection (p = 0.024) were associated with fatal outcome. In multivariate analysis, influenza-like prodrome (odds ratio (OR), 7.44; 95% confidence interval (CI), 1.24-44.76; p = 0.028) and absence of previous skin and soft-tissue infection (OR, 0.09; 95% CI, 0.01-0.86; p = 0.036) remained significant predictors of death.

CONCLUSIONS

Influenza-like prodrome may be predictive of adverse outcome in PVL-secreting MSSA necrotizing pneumonia. In contrast, previous skin and soft-tissue infection may be associated with improved prognosis.

Bacteriological and clinical profile of Community acquired pneumonia in hospitalized patients

The aim of our study was to obtain comprehensive insight into the bacteriological and clinical profile of community-acquired pneumonia requiring hospitalization. The patient population consisted of 100 patients admitted with the diagnosis of community-acquired pneumonia (CAP), as defined by British Thoracic society, from December 1998 to Dec 2000, at the Sher- i-Kashmir institute of Medical Sciences Soura, Srinagar, India. Gram negative organisms were the commonest cause (19/29), followed by gram positive (10/29). In 71 cases no etiological cause was obtained. Pseudomonas aeruginosa was the commonest pathogen (10/29), followed by Staphylococcus aureus (7/29), Escherichia coli (6/29), Klebsiella spp. (3/29), Streptococcus pyogenes (1/29), Streptococcus pneumoniae (1/29) and Acinetobacter spp. (1/29). Sputum was the most common etiological source of organism isolation (26) followed by blood (6), pleural fluid (3), and pus culture (1). Maximum number of patients presented with cough (99%), fever (95%), tachycardia (92%), pleuritic chest pain (75%), sputum production (65%) and leucocytosis (43%). The commonest predisposing factors were smoking (65%), COPD (57%), structural lung disease (21%), diabetes mellitus (13%), and decreased level of consciousness following seizure (eight per cent) and chronic alcoholism (one per cent). Fourteen patients, of whom, nine were males and five females, died. Staphylococcus aureus was the causative organism in four, Pseudomonas in two, Klebsiella in one, and no organism was isolated in seven cases. The factors predicting mortality at admission were - age over 62 years, history of COPD or smoking, hypotension, altered sensorium, respiratory failure, leucocytosis, and staphylococcus pneumonia and undetermined etiology. The overall rate of identification of microbial etiology of community-acquired pneumonia was 29%, which is very low, and if serological tests for legionella, mycoplasma and viruses are performed the diagnostic yield would definitely be better. This emphasizes the need for further studies (including the serological tests for Legionella, mycoplasma and viruses) to identify the microbial etiology of CAP.

Mycoplasma pneumoniae infection in primary care investigated by real-time PCR in England and Wales

Real-time PCR was employed to detect a conserved region of the P1 cytadhesin gene of Mycoplasma pneumoniae in combined nose and throat swabs collected from patients attending GP surgeries during 2005-2009 with symptoms of respiratory tract infection (RTI). Samples were collected as part of an annual winter epidemiological and virological linked study in England and Wales. A total of 3,987 samples were tested, 65 (1.7%, 95%CI 1.3-2.1) had detectable M. pneumoniae DNA. Positive patients were detected of both gender, aged from 9 months to 78 years, who had clinical signs of upper RTI, fever and/or myalgia, an influenza-like illness to lower RTI. Mixed infections were identified in four cases, two with influenza A H1, one with H3 and one with influenza B. Children aged 5-14 years were more likely to have detectable M. pneumoniae in samples than all other age groups (Fishers p = 0.03), attributed to the 2005-2006 season in which 6.0% (12/200, 95%CI 3.4-10.3) of 5-14 year olds had detectable M. pneumoniae in comparison to 2.2% in 2006-2007 (3/141 95%CI 0.5-6.4), 2.2% in 2007-2008 (2/89 95%CI 0.1-8.3) and 0% in 2008-2009 (0/151 95%CI 0-2.9).

Clinical and economic burden of pneumococcal disease in older US adults

We developed a model characterizing rates and costs of pneumococcal disease in the US to estimate the expected annual clinical and economic burden of this condition among older adults. Among the 91.5 million US adults aged >or=50 years, 29,500 cases of invasive pneumococcal disease, 502,600 cases of nonbacteremic pneumococcal pneumonia, and 25,400 pneumococcal-related deaths are estimated to occur yearly; annual direct and indirect costs are estimated to total $3.7 billion and $1.8 billion, respectively. Pneumococcal disease remains a substantial burden among older US adults, despite increased coverage with PPV23 and indirect benefits afforded by PCV7 vaccination of young children.

Subtypes and variants ofMycoplasma pneumoniae: local and temporal changes in Germany 2003–2006 and absence of a correlation between the genotype in the respiratory tract and the occurrence of genotype-specific antibodies in the sera of infected patients

Mycoplasma pneumoniaeis a frequent cause of community-acquired pneumonia. Three subtypes and three variants ofM. pneumoniaehave been described showing sequence differences in the main P1 adhesin. Between 2003 and 2006 we collected respiratory tract samples of adult outpatients with symptoms of pneumonia in a German nationwide network and detectedM. pneumoniaeby real-time PCR in 140 specimens. The strains were typed by sequencing and demonstrated the circulation of subtypes 1 and 2 and variants 2a and 2b. The overall number of isolates belonging to the two variant genotypes increased during the investigation period but the relationship of subtypes and variants within the participating local centres varied strongly. ELISA experiments using sera of acute-phase patients with a knownM. pneumoniaetype in the respiratory tract resulted in no correlation of IgA and IgG antibodies to subtype- and variant-specific regions of theP1gene with the genotype of theM. pneumoniaestrain causing the actual infection.

Etiology of community-acquired pneumonia: increased microbiological yield with new diagnostic methods

BACKGROUND

The microbial etiology of community-acquired pneumonia (CAP) is still not well characterized. During the past few years, polymerase chain reaction (PCR)-based methods have been developed for many pathogens causing respiratory tract infections. The aim of this study was to determine the etiology of CAP among adults-especially the occurrence of mixed infections among patients with CAP-by implementing a new diagnostic PCR platform combined with conventional methods.

METHODS

Adults admitted to Karolinska University Hospital were studied prospectively during a 12-month period. Microbiological testing methods included culture from blood, sputum, and nasopharyngeal secretion samples; sputum samples analyzed by real-time quantitative PCR for Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis; nasopharyngeal specimens analyzed by use of PCR; serological testing for Mycoplasma pneumoniae, Chlamydophila pneumoniae, and viruses common in the respiratory tract; and urine antigen assays for detection of pneumococcal and Legionella pneumophila antigens.

RESULTS

A microbial etiology could be identified for 67% of the patients (n = 124). For patients with complete sampling, a microbiological agent was identified for 89% of the cases. The most frequently detected pathogens were S. pneumoniae (70 patients [38%]) and respiratory virus (53 patients [29%]). Two or more pathogens were present in 43 (35%) of 124 cases with a determined etiology.

CONCLUSIONS

By supplementing traditional diagnostic methods with new PCR-based methods, a high microbial yield was achieved. This was especially evident for patients with complete sampling. Mixed infections were frequent (most commonly S. pneumoniae together with a respiratory virus).

Macrolide-resistant Mycoplasma pneumoniae: characteristics of isolates and clinical aspects of community-acquired pneumonia

Mycoplasma pneumoniae is one of the main pathogens causing community-acquired respiratory tract infections in children and adults. Macrolide (ML) antibiotics are recognized generally as first-choice agents for M. pneumoniae infections, and these antibiotics were thought to have excellent effectiveness against M. pneumoniae for many years. In 2000, however, M. pneumoniae showing resistance to macrolides was isolated from clinical samples obtained from Japanese pediatric patients with community-acquired pneumonia (CAP). Since then, prevalence of ML-resistant M. pneumoniae isolates in pediatric patients has increased rapidly. In 2007, ML-resistant M. pneumoniae isolates were obtained from Japanese adults with CAP; numbers of such isolates also have gradually increased in Japan. Recently, similar antimicrobial resistance in M. pneumoniae has begun to emerge worldwide. In this review, we focus on changes of ML-resistant M. pneumoniae from year to year and consider resistance mechanisms as well as clinical features of patients with resistant M. pneumoniae infection.

Hospital-acquired pneumonia: pathophysiology, diagnosis, and treatment

Hospital-acquired pneumonia (HAP) is one of the most common causes of nosocomial infection, morbidity, and mortality in hospitalized patients. Many patient- and disease-specific factors contribute to the pathophysiology of HAP, particularly in the surgical population. Risk-factor modification and inpatient prevention strategies can have a significant impact on the incidence of HAP. While the best diagnostic strategy remains a subject of some debate, prompt and appropriate antimicrobial therapy in patients suspected of having HAP has been shown to significantly decrease mortality. Because the pathogens responsible for HAP are frequently more virulent and have greater resistance to commonly used antimicrobials than other pathogens, clinicians must have knowledge of the resistance patterns at their institutions to choose appropriate therapy.

Viral infection in adults hospitalized with community-acquired pneumonia: prevalence, pathogens, and presentation

Background

The potential role of respiratory viruses in the natural history of community-acquired pneumonia (CAP) in adults has not been well described since the advent of nucleic amplification tests (NATs).

Methods

From 2004 to 2006, adults with CAP who were admitted to five hospitals were prospectively enrolled in the study, and clinical data, cultures, serology, and nasopharyngeal swabs were obtained. NATs from swabs were tested for influenza, human metapneumovirus (hMPV), respiratory syncytial virus (RSV), rhinovirus, parainfluenza virus 1–4, coronaviruses (OC43, 229E, and NL63), and adenovirus.

Results

A total of 193 patients were included; the median age was 71 years, 51% of patients were male, and 47% of patients had severe CAP. Overall, 75 patients (39%) had a pathogen identified. Of these pathogens, 29 were viruses (15%), 38 were bacteria (20%), 8 were mixed (4%), and the rest were “unknown.” Influenza (n = 7), hMPV (n = 7), and RSV (n = 5) accounted for most viral infections; other infections included rhinovirus (n = 4), parainfluenza (n = 3), coronavirus (n = 4), and adenovirus (n = 2). Streptococcus pneumoniae was the most common bacterial infection (37%). Compared with bacterial infection, patients with viral infection were older (76 vs 64 years, respectively; p = 0.01), were more likely to have cardiac disease (66% vs 32%, respectively; p = 0.006), and were more frail (eg, 48% with limited ambulation vs 21% of bacterial infections; p = 0.02). There were few clinically meaningful differences in presentation and no differences in outcomes according to the presence or absence of viral infection.

Conclusions

Viral infections are common in adults with pneumonia. Easily transmissible viruses such as influenza, hMPV, and RSV were the most common, raising concerns about infection control. Routine testing for respiratory viruses may be warranted for adults who have been hospitalized with pneumonia.

The bacteriology of pneumonia diagnosed in Western Australian emergency departments

We used Western Australian emergency department data linked to hospital morbidity, death and microbiology data to describe the bacteriology of pneumonia according to age. The 'atypical' organisms and viruses were not assessed. A total of 6908 patients over a 3-year period were given an emergency department diagnosis of pneumonia, 76.9% were admitted and 6.3% died in hospital. Blood was cultured from 52.9% of patients with 6.4% growing potential pathogens. Streptococcus pneumoniae was the most common organism isolated and accounted for 92% of pathogens in those aged <15 years. Isolation of Enterobacteriaceae species tended to increase with age and accounted for around 25% of isolates from the elderly. Sputum was cultured from 25.3% of patients and bacteria were isolated from 30.3% of samples, commonly Haemophilus influenzae and S. pneumoniae. Isolates from sputum showed no distinct trend across age groups. These patterns question the value of routine blood and sputum cultures and have implications for empiric therapy for the elderly.

[Managing lower respiratory tract infections in immunocompetent patients. Definitions, epidemiology, and diagnostic features]

Les infections respiratoires basses sont une des principales cause de mortalité dans le monde et les pneumopathies représentent en France la première cause de décès d'origine infectieuse. Trois entités nosologiques distinctes sont habituellement isolées en fonction de la localisation infectieuse : la bronchite aiguë, la pneumopathie et la bronchopneumopathie (atteignant les bronches et le parenchyme pulmonaire). En cas d'infections de l'arbre bronchique dans le cadre d'une bronchopathie chronique on parle de décompensation infectieuse de la maladie bronchique. Les deux principales difficultés diagnostiques de ces infections sont de déterminer la présence d'une participation alvéolaire au processus infectieux et de définir l'agent (ou les agents) pathogènes. Ces deux éléments vont conditionner la prise en charge thérapeutique. En dehors de l'examen physique, indispensable dans ce contexte, seule la radiographie thoracique pourra, en cas de persistance d'un doute, permettre de confirmer la présence d'une participation alvéolaire. Le diagnostic microbiologique pose la question de sa nécessité systématique et celui de sa valeur. Il n'est pas indispensable de réaliser un diagnostic microbiologique de certitude dans tous les cas. La décision de documentation doit répondre à deux impératifs : faisabilité et valeur diagnostique. La valeur d'un prélèvement dépend de son aptitude à mettre en évidence l'agent pathogène et dans certains cas de la possibilité d'en déterminer le profil de sensibilité (qui reste une indication majeure à la réalisation de ces prélèvements).

The Role of Viruses in the Aetiology of Community-Acquired Pneumonia in Adults

Background

The role of viruses in community-acquired pneumonia may have been previously underestimated. We aimed to study the incidence and clinical characteristics of community-acquired pneumonia (CAP) due to respiratory viruses in adults adding PCR to routine conventional laboratory tests.

Methods

Consecutive adult patients diagnosed of CAP from January 2003 to March 2004 were included. Conventional tests including cultures of blood, sputum, urine antigen detection of Streptococcus pneumoniae and Legionella pneumophila, and paired serologies were routinely performed. Nasopharyngeal swabs were processed for study of respiratory viruses through antigen detection by indirect immunofluorescence assay, isolation of viruses in cell culture and detection of nucleic acids by two independent multiplex RT-PCR assays. According to the aetiology, patients were categorized in 4 groups: group 1, only virus detected; group 2, only bacteria detected; group 3, viral and bacterial; and group 4, unkown aetiology.

Results

Of 340 patients diagnosed with CAP, 198 had nasopharyngeal swabs available and were included in this study. Aetiology was established in 112 (57%) patients: group 1, n=26 (13%); group 2, n=66 (33%); group 3, n=20 (10%). The most common aetiological agent was S. neumoniae (58 patients, 29%), followed by respiratory viruses (46 patients, 23%). Forty-eight respiratory viruses were identified: influenza virus A ( n=16), respiratory syncytial virus A ( n=5), adenovirus ( n=8), parainfluenza viruses ( n=5), enteroviruses ( n=1), rhinoviruses ( n=8) and coronavirus ( n=5). There were two patients coinfected by two respiratory viruses. Serology detected 6 viruses, immunofluorescence 8, viral culture 12, and PCR 45. For the viruses that could be diagnosed with conventional methods, the sensitivity and specificity of RT-PCR was 85% and 92%, respectively. The only clinical characteristic that significantly distinguished viral from bacterial aetiology was a lower number of leukocytes ( P=0.004).

Conclusion

PCR revealed that viruses represent a common aetiology of CAP. There is an urgent need to reconsider routine laboratory tests for an adequate diagnosis of respiratory viruses, as clinical characteristics are unable to reliably distinguish viral from bacterial aetiology.