Impact of initial antibiotic choice on mortality from pneumococcal pneumonia

Sepsis-Related Lung Injury and the Complication of Extrapulmonary Pneumococcal Pneumonia

Globally, sepsis and pneumonia account for significant mortality and morbidity. A complex interplay of immune-molecular pathways underlies both sepsis and pneumonia, resulting in similar and overlapping disease characteristics. Sepsis could result from unmanaged pneumonia. Similarly, sepsis patients have pneumonia as a common complication in the intensive care unit. A significant percentage of pneumonia is misdiagnosed as septic shock. Therefore, our knowledge of the clinical relationship between pneumonia and sepsis is imperative to the proper management of these syndromes. Regarding pathogenesis and etiology, pneumococcus is one of the leading pathogens implicated in both pneumonia and sepsis syndromes. Growing evidence suggests that pneumococcal pneumonia can potentially disseminate and consequently induce systemic inflammation and severe sepsis. Streptococcus pneumoniae could potentially exploit the function of dendritic cells (DCs) to facilitate bacterial dissemination. This highlights the importance of pathogen-immune cell crosstalk in the pathophysiology of sepsis and pneumonia. The role of DCs in pneumococcal infections and sepsis is not well understood. Therefore, studying the immunologic crosstalk between pneumococcus and host immune mediators is crucial to elucidating the pathophysiology of pneumonia-induced lung injury and sepsis. This knowledge would help mitigate clinical diagnosis and management challenges.

Host genetic variants associated with susceptibility and severity of pneumococcal pneumonia in adult patients

BACKGROUND

Pneumococcal community-acquired pneumonia (P-CAP) is a major cause of morbidity and hospitalization. Several host genetics factors influencing risk of pneumococcal disease have been identified, with less information about its association with P-CAP. The aim of the study was to assess the influence of single nucleotide polymorphisms (SNP) within key genes involved in the innate immune response on the susceptibility to P-CAP and to study whether these polymorphic variants were associated with the severity and outcome of the episodes in a cohort of adult Caucasian patients.

METHODS

Seventeen SNPs from 7 genes (IL-R1, IL-4, IL-10, IL-12B, NFKBIA, NFKBIE, NFKBIZ) were analyzed. For susceptibility, a case-control study including a cohort of 57 adult with P-CAP, and 280 ethnically matched controls was performed. Genetic influence on clinical severity and outcome was evaluated in a prospective observational study including all consecutive adult P-CAP patients from November 2015 to May 2017.

RESULTS

The NFKBIA polymorphism rs696 and a haplotype combination were associated with susceptibility to P-CAP (OR = 0.62, p = 0.005 and OR = 0.63, p = 0.008, respectively). The SNP IL4 rs2227284 was associated with severe P-CAP (OR = 2.17, p = 0.04). IL-R1 (rs3917267) and IL-10 (rs3024509) variants were related with respiratory failure (OR = 3.31, p = 0.001 and OR = 0.18, p = 0.003, respectively) as well as several haplotype combinations in NFKBIA, NFKBIZ, IL-R1 and IL-10 (p = 0,02, p = 0,01, p = 0,001, p = 0,03, respectively). CURB-65 values were associated with the IL-10 rs3024509 variant (beta = - 0.4, p = 0.04), and with haplotype combinations of NFKBIZ and IL-10 (p = 0.05, p = 0.04, respectively). Genetic variants in IL-10 (rs3024509) and in IL-12B (rs730691) were associated with PSI values (beta = - 0.54, p = 0.01, and beta = - 0.28, p = 0.04, respectively), as were allelic combinations in IL-R1 (p = 0.02) and IL-10 (p = 0.01). Finally, several polymorphisms in the IL-R1 gene (rs13020778, rs2160227, & rs3917267) were associated with the time elapsed until clinical stability (beta = - 0.83, p = 0.03; beta = - 1, p = 0.02 and beta = 1.07, p = 0.008, respectively).

CONCLUSIONS

A genetic variant in NFKBIA was associated with susceptibility to P-CAP in adult Caucasian patients and genetic variants from key cytokines of the innate immune response (Il-4, IL-10, IL-R1 and IL-12B) and NF-κB inhibitors were associated with different phenotypes of severe P-CAP. If validated, these SNPs may help to identify people at risk of P-CAP or severe P-CAP on which preventive measures could be applied.

Macrolides for better resolution of community-acquired pneumonia: A global meta-analysis of clinical outcomes with focus on microbial aetiology

OBJECTIVES

This meta-analysis examined the effect of macrolides on resolution of community-acquired pneumonia (CAP) and interpretation of clinical benefit according to microbiology; emphasis is given to data under-reported countries (URCs).

METHODS

This meta-analysis included 47 publications published between 1994 and 2022. Publications were analysed for 30-d mortality (58 759 patients) and resolution of CAP (6465 patients). A separate meta-analysis was done for the prevalence of respiratory pathogens in URCs.

RESULTS

Mortality after 30 d was reduced by the addition of macrolides (odds ratio [OR] 0.65, 95% confidence interval [CI] 0.51-0.82). The OR for CAP resolution when macrolides were added to the treatment regimen was 1.23 (95% CI 1.00-1.52). In the CAP resolution analysis, the most prevalent pathogen was Streptococcus pneumoniae (12.68%; 95% CI 9.36-16.95%). Analysis of the pathogen epidemiology from the URCs included 12 publications. The most prevalent pathogens were S. pneumoniae (24.91%) and Klebsiella pneumoniae (12.90%).

CONCLUSION

The addition of macrolides to the treatment regimen led to 35% relative decrease of 30-d mortality and to 23% relative increase in resolution of CAP.

Multidisciplinary Collaboration for the Optimization of Antibiotic Prescription: Analysis of Clinical Cases of Pneumonia between Emergency, Internal Medicine, and Pharmacy Services

BACKGROUND

Pneumonia is a lung parenchyma acute infection usually treated with antibiotics. Increasing bacterial resistances force the review and control of antibiotic use criteria in different health departments.

OBJECTIVE

Evaluate the adequacy of antibiotic treatment in community-acquired pneumonia in patients initially attended at the emergency department and then admitted to the internal medicine service of the Alto Deba Hospital-Osakidetza Basque Country Health Service (Spain).

METHODS

Observational, retrospective study, based on the review of medical records of patients with community-acquired pneumonia attended at the hospital between January and May 2021. The review was made considering the following items: antimicrobial treatment indication, choice of antibiotic, time of administration of the first dose, adequacy of the de-escalation-sequential therapy, duration of treatment, monitoring of efficacy and adverse effects, and registry in the medical records. The review was made by the research team (professionals from the emergency department, internal medicine, and pharmacy services).

RESULTS

Fifty-five medical records were reviewed. The adequacy of the treatments showed that antibiotic indication, time of administration of the first dose, and monitoring of efficacy and adverse effects were the items with the greatest agreement between the three departments. This was not the case with the choice of antibiotic, de-escalation/sequential therapy, duration of treatment, and registration in the medical record, which have been widely discussed. The choice of antibiotic was optimal in 63.64% and might have been better in 25.45%. De-escalation/oral sequencing might have been better in 50.91%. The treatment duration was optimal in 45.45% of the patients and excessive in 45.45%.

DISCUSSION

The team agreed to disseminate these data among the hospital professionals and to propose audits and feedback through an antibiotic stewardship program. Besides this, implementing the local guideline and defining stability criteria to apply sequential therapy/de-escalation was considered essential.

Related Factors to Streptococcus pneumoniae Invasive Infection and Clinical Manifestations: The Potential Role of Nasopharyngeal Microbiome

Infections of the lower respiratory tract, such as pneumonia, are one of the leading causes of death worldwide. Streptococcus pneumoniae might colonize the upper respiratory tract and is the main aetiological agent of community-acquired pneumonia (CAP). In the last decades, several factors related to the host, the microorganism and the antibiotic therapy have been investigated to identify risk factors associated with the development of invasive pneumococcal disease (IPD). Nevertheless, these factors themselves do not explain the risk of developing disease or its severity. Recently, some studies have focused on the importance of nasopharyngeal (NP) microbiome and its relation to respiratory health. This review presents existing evidence of the potential role of NP microbiome in the development of IPD.

Treatment and prevention of invasive pneumococcal disease

Invasive pneumococcal disease is a severe infection that mainly affects patients with associated comorbidity. The paediatric conjugate vaccination has resulted in a change in the adult vaccination strategy. The antibiotic resistance of pneumococcus is not currently a severe problem. Nevertheless, the World Health Organisation has included pneumococcus among the bacteria whose treatment requires the introduction of new drugs, such as ceftaroline and ceftobiprole. Although the scientific evidence is still limited, the combination of beta-lactams and macrolides is recommended as empiric therapy for bacteraemic pneumococcal pneumonia.

The dilemma of monotherapy or combination therapy in community-acquired pneumonia

SCOPE

To study the factors associated with mortality in hospitalized patients with community-acquired pneumonia treated with monotherapy or combination therapy.

METHODS

PubMed and Scopus were searched. Patients receiving macrolides, β-lactams and fluoroquinolones, as monotherapy or in combination, were included. Meta-analyses and meta-regressions were performed.

RESULTS

Fifty studies were included. Overall, monotherapy was not associated with higher mortality than combination (RR 1.14, 95% CI 0.99-1.32, I² 84%). Monotherapy was associated with higher mortality than combination in North American and retrospective studies. β-lactam monotherapy was associated with higher mortality than β-lactam/macrolide combination in the primary (1.32, 1.12-1.56, I² 85%) and most sensitivity analyses. There was no difference in mortality between fluoroquinolone monotherapy and β-lactam/macrolide combination (0.98, 0.78-1.23, I² 73%). In meta-regressions, the moderators that could partially explain the observed statistical heterogeneity were the frequency of cancer patients (P = .03) and Pneumonia Severity Index score IV (P = .008).

CONCLUSION

Due to the considerable heterogeneity and inclusion of unadjusted data, it is difficult to recommend a specific antibiotic regimen over another. Specific antibiotic regimens, study design and the characteristics of the population under study seem to influence the reported outcomes.

Impact of antibiotic therapy in severe community-acquired pneumonia: Data from the Infauci study

Antibiotic therapy (AT) is the cornerstone of the management of severe community-acquired pneumonia (CAP). However, the best treatment strategy is far from being established. To evaluate the impact of different aspects of AT on the outcome of critically ill patients with CAP, we performed a post hoc analysis of all CAP patients enrolled in a prospective, observational, multicentre study. Of the 502 patients included, 76% received combination therapy, mainly a β-lactam with a macrolide (80%). AT was inappropriate in 16% of all microbiologically documented CAP (n=177). Hospital and 6months mortality were 34% and 35%. In adjusted multivariate logistic regression analysis, combination AT with a macrolide was independently associated with a reduction in hospital (OR 0.17, 95%CI 0.06-0.51) and 6months (OR 0.21, 95%CI 0.07-0.57) mortality. Prolonged AT (>7days) was associated with a longer ICU (14 vs. 7days; p<0.001) and hospital length of stay (LOS) (25 vs. 17days; p<0.001). Combination AT with a macrolide may be the most suitable AT strategy to improve both short and long term outcome of severe CAP patients. AT >7days had no survival benefit and was associated with a longer LOS.

The order of administration of macrolides and beta-lactams may impact the outcomes of hospitalized patients with community-acquired pneumonia: results from the community-acquired pneumonia organization

BACKGROUND

The beneficial effect of macrolides for the treatment of community-acquired pneumonia (CAP) in combination with beta-lactams may be due to their anti-inflammatory activity. In patients with pneumococcal meningitis, the use of steroids improves outcomes only if they are administered before beta-lactams. The objective of this study was to compare outcomes in hospitalized patients with CAP when macrolides were administered before, simultaneously with, or after beta-lactams.

METHODS

Secondary data analysis of the Community-Acquired Pneumonia Organization (CAPO) International Cohort Study database. Study groups were defined based on the sequence of administration of macrolides and beta-lactams. The study outcomes were time to clinical stability (TCS), length of stay (LOS) and in-hospital mortality. Accelerated failure time models were used to evaluate the adjusted impact of sequential antibiotic administration and time-to-event outcomes, while a logistic regression model was used to evaluate their adjusted impact on mortality.

RESULTS

A total of 99 patients were included in the macrolide before group and 305 in the macrolide after group. Administration of a macrolide before a beta-lactam compared to after a beta-lactam reduced TCS (3 vs. 4 days, p = .011), LOS (6 vs. 7 days, p = .002) and mortality (3 vs. 7.2%, p = .228).

CONCLUSIONS

The administration of macrolides before beta-lactams was associated with a statistically significant decrease in TCS and LOS and a non-statistically significant decrease in mortality. The beneficial effect of macrolides in hospitalized patient with CAP may occur only if administered before beta-lactams.

Using cluster analysis of cytokines to identify patterns of inflammation in hospitalized patients with community-acquired pneumonia: a pilot study

INTRODUCTION

Patients with severe community-acquired pneumonia (CAP) are believed to have an exaggerated inflammatory response to bacterial infection. Therapies aiming to modulate the inflammatory response have been largely unsuccessful, perhaps reflecting that CAP is a heterogeneous disorder that cannot be modulated by a single anti-inflammatory approach. We hypothesize that the host inflammatory response to pneumonia may be characterized by distinct cytokine patterns, which can be harnessed for personalized therapies.

METHODS

Here, we use hierarchical cluster analysis of cytokines to examine if patterns of inflammatory response in 13 hospitalized patients with CAP can be defined. This was a secondary data analysis of the Community-Acquired Pneumonia Inflammatory Study Group (CAPISG) database. The following cytokines were measured in plasma and sputum on the day of admission: interleukin (IL)-1β, IL-1 receptor antagonist (IL-1ra), IL-6, CXCL8 (IL-8), IL-10, IL-12p40, IL-17, interferon (IFN)γ, tumor necrosis factor (TNF)α, and CXCL10 (IP-10). Hierarchical agglomerative clustering algorithms were used to evaluate clusters of patients within plasma and sputum cytokine determinations.

RESULTS

A total of thirteen patients were included in this pilot study. Cluster analysis identified distinct inflammatory response patterns of cytokines in the plasma, sputum, and the ratio of plasma to sputum.

CONCLUSIONS

Inflammatory response patterns in plasma and sputum can be identified in hospitalized patients with CAP. Characterization of the local and systemic inflammatory response may help to better discriminate patients for enrollment into clinical trials of immunomodulatory therapies.

Using cluster analysis of cytokines to identify patterns of inflammation in hospitalized patients with community-acquired pneumonia: a pilot study

INTRODUCTION

Patients with severe community-acquired pneumonia (CAP) are believed to have an exaggerated inflammatory response to bacterial infection. Therapies aiming to modulate the inflammatory response have been largely unsuccessful, perhaps reflecting that CAP is a heterogeneous disorder that cannot be modulated by a single anti-inflammatory approach. We hypothesize that the host inflammatory response to pneumonia may be characterized by distinct cytokine patterns, which can be harnessed for personalized therapies.

METHODS

Here, we use hierarchical cluster analysis of cytokines to examine if patterns of inflammatory response in 13 hospitalized patients with CAP can be defined. This was a secondary data analysis of the Community-Acquired Pneumonia Inflammatory Study Group (CAPISG) database. The following cytokines were measured in plasma and sputum on the day of admission: interleukin (IL)-1β, IL-1 receptor antagonist (IL-1ra), IL-6, CXCL8 (IL-8), IL-10, IL-12p40, IL-17, interferon (IFN)γ, tumor necrosis factor (TNF)α, and CXCL10 (IP-10). Hierarchical agglomerative clustering algorithms were used to evaluate clusters of patients within plasma and sputum cytokine determinations.

RESULTS

A total of thirteen patients were included in this pilot study. Cluster analysis identified distinct inflammatory response patterns of cytokines in the plasma, sputum, and the ratio of plasma to sputum.

CONCLUSIONS

Inflammatory response patterns in plasma and sputum can be identified in hospitalized patients with CAP. Characterization of the local and systemic inflammatory response may help to better discriminate patients for enrollment into clinical trials of immunomodulatory therapies.

Host-directed therapies for infectious diseases: current status, recent progress, and future prospects

Despite extensive global efforts in the fight against killer infectious diseases, they still cause one in four deaths worldwide and are important causes of long-term functional disability arising from tissue damage. The continuing epidemics of tuberculosis, HIV, malaria, and influenza, and the emergence of novel zoonotic pathogens represent major clinical management challenges worldwide. Newer approaches to improving treatment outcomes are needed to reduce the high morbidity and mortality caused by infectious diseases. Recent insights into pathogen–host interactions, pathogenesis, inflammatory pathways, and the host's innate and acquired immune responses are leading to identification and development of a wide range of host-directed therapies with different mechanisms of action. Host-directed therapeutic strategies are now becoming viable adjuncts to standard antimicrobial treatment. Host-directed therapies include commonly used drugs for non-communicable diseases with good safety profiles, immunomodulatory agents, biologics (eg monoclonal antibodies), nutritional products, and cellular therapy using the patient's own immune or bone marrow mesenchymal stromal cells. We discuss clinically relevant examples of progress in identifying host-directed therapies as adjunct treatment options for bacterial, viral, and parasitic infectious diseases.

Beta-lactam plus macrolides or beta-lactam alone for community-acquired pneumonia: A systematic review and meta-analysis

It is unclear whether in the treatment of community-acquired pneumonia (CAP) beta-lactam plus macrolide antibiotics lead to better survival than beta-lactam alone. We report a systematic review and meta-analysis. Trials and observational studies published in English were included, if they provided sufficient data on odds ratio for all-cause mortality for a beta-lactam plus macrolide regimen compared with beta-lactam alone. Two investigators independently searched for eligible articles. Of 514 articles screened, 14 were included: two open-label randomized controlled trials (RCTs) comprising 1975 patients, one non-RCT interventional study comprising 1011 patients and 11 observational studies comprising 33 332 patients. Random-model meta-analysis yielded an odds ratio for all-cause death for beta-lactam plus macrolide compared with beta-lactam alone of 0.80 (95% CI 0.69-0.92, P = 0.002) with substantial heterogeneity (I(2)  = 59%, P for heterogeneity = 0.002). Severity-based subgroup analysis and meta-regression revealed that adding macrolide had a favourable effect on mortality only for severe CAP. Of the two RCTs, one suggested that macrolide plus beta-lactam lead to better outcome compared with beta-lactam alone, while the other did not. Subgrouping based on study design, that is, RCT versus non-RCT, which was almost identical to subgrouping based on severity, revealed substantial inter-subgroup heterogeneity. Compared with beta-lactam alone, beta-lactam plus macrolide may decrease all-cause death only for severe CAP. However, this conclusion is tentative because this was based mainly on observational studies.

Lung inflammatory pattern and antibiotic treatment in pneumonia

BACKGROUND

In community-acquired pneumonia host inflammatory response against the causative microorganism is necessary for infection resolution. However an excessive response can have deleterious effects. In addition to antimicrobial effects, macrolide antibiotics are known to possess immunomodulatory properties.

METHODS

A prospective study was performed on 52 admitted patients who developed an inadequate response after 72 hours of antibiotic treatment - non-responders community-acquired pneumonia - (blood and bronchoalveolar lavage), and two control groups: 1) community-acquired pneumonia control (blood) and 2) non-infection control (blood and bronchoalveolar lavage). Cytokine profiles (interleukin (IL)-6, IL-8, IL-10), tumour necrosis factor α and clinical outcomes were assessed.

RESULTS

Non-responders patients treated with macrolide containing regimens showed significantly lower levels of IL-6 and TNF-α in bronchoalveolar lavage fluid and lower IL-8 and IL-10 in blood than those patients treated with non-macrolide regimens. Clinical outcomes showed that patients treated with macrolide regimens required fewer days to reach clinical stability (p < 0.01) and shorter hospitalization periods (p < 0.01).

CONCLUSIONS

After 72 hours of antibiotic effect, patients who received macrolide containing regimens exhibited lower inflammatory cytokine levels in pulmonary and systemic compartments along with faster stabilization of infectious parameters.

Pneumococcal colonisation density: a new marker for disease severity in HIV-infected adults with pneumonia

OBJECTIVE

A high genomic load of Pneumococcus from blood or cerebrospinal fluid has been associated with increased mortality. We aimed to analyse whether nasopharyngeal colonisation density in HIV-infected patients with community-acquired pneumonia (CAP) is associated with markers of disease severity or poor outcome.

METHODS

Quantitative lytA real-time PCR was performed on nasopharyngeal swabs in HIV-infected South African adults hospitalised for acute CAP at Chris Hani Baragwanath Hospital, Soweto, South Africa. Pneumonia aetiology was considered pneumococcal if any sputum culture or Gram stain, urinary pneumococcal C-polysaccharide-based antigen, blood culture or whole blood lytA real-time PCR revealed pneumococci.

RESULTS

There was a moderate correlation between the mean nasopharyngeal colonisation densities and increasing CURB65 scores among all-cause patients with pneumonia (Spearman correlation coefficient r=0.15, p=0.06) or with the Pitt bacteraemia score among patients with pneumococcal bacteraemia (p=0.63). In patients with pneumococcal pneumonia, nasopharyngeal pneumococcal colonisation density was higher among non-survivors than survivors (7.7 vs 6.1 log10 copies/mL, respectively, p=0.02) and among those who had pneumococci identified from blood cultures and/or by whole blood lytA real-time PCR than those with non-bacteraemic pneumococcal pneumonia (6.6 vs 5.6 log10 copies/mL, p=0.03). Nasopharyngeal colonisation density correlated positively with the biomarkers procalcitonin (Spearman correlation coefficient r=0.37, p<0.0001), proadrenomedullin (r=0.39, p=0.008) and copeptin (r=0.30, p=0.01).

CONCLUSIONS

In addition to its previously reported role as a diagnostic tool for pneumococcal pneumonia, quantitative nasopharyngeal colonisation density also correlates with mortality and prognostic biomarkers. It may also be useful as a severity marker for pneumococcal pneumonia in HIV-infected adults.

Contemporary use of ceftaroline fosamil for the treatment of community-acquired bacterial pneumonia: CAPTURE study experience

The Clinical Assessment Program and Teflaro(®) Utilization Registry (CAPTURE) is a multicenter cohort study designed to collect information on the contemporary use of ceftaroline fosamil in the US. Data collected from 398 evaluable patients with community-acquired bacterial pneumonia (CABP) (mean age 64 years) during the first 18 months of the study are presented. Most patients had co-morbidities (76%; primarily structural lung disease), and ≧2 signs and symptoms of CABP (76%). Overall clinical success was 79% which varied little with ceftaroline fosamil usage (monotherapy vs concurrent therapy; first-line vs second-line therapy). Most patients were discharged home (60%) or to another healthcare facility (35%). These data suggest that ceftaroline, in contemporary clinical use, is an effective antibiotic for the treatment of patients with CABP, including those with significant co-morbidities or who required a change of their prior antibiotic therapy.

Impact of macrolide therapy in patients hospitalized with Pseudomonas aeruginosa community-acquired pneumonia

BACKGROUND

Several studies have described a clinical benefit of macrolides due to their immunomodulatory properties in various respiratory diseases. We aimed to assess the effect of macrolide therapy on mortality in patients hospitalized for Pseudomonas aeruginosa community-acquired pneumonia (CAP).

METHODS

We performed a retrospective population-based study of &gt; 150 hospitals in the US Veterans Health Administration. Patients were included if they had a diagnosis of CAP and P aeruginosa was identified as the causative pathogen. Patients with health-care-associated pneumonia and immunosuppression were excluded. Macrolide therapy was considered when administered within the first 48 h of admission. Univariate and multivariable analyses were performed using 30-day mortality as the dependent measure.

RESULTS

We included 402 patients with P aeruginosa CAP, of whom 171 (42.5%) received a macrolide during the first 48 h of admission. These patients were older and white. Macrolide use was not associated with lower 30-day mortality (hazard ratio, 1.14; 95% CI, 0.70-1.83; P = .5). In addition, patients treated with macrolides had no differences in ICU admission, use of mechanical ventilation, use of vasopressors, and length of stay (LOS) compared with patients not treated with macrolides. A subgroup analysis among patients with P aeruginosa CAP in the ICU showed no differences in baseline characteristics and outcomes.

CONCLUSIONS

Macrolide therapy in the first 48 h of admission is not associated with decreased 30-day mortality, ICU admission, need for mechanical ventilation, and LOS in hospitalized patients with P aeruginosa CAP. Larger cohort studies should address the benefit of macrolides as immunomodulators in patients with P aeruginosa CAP.

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.

Macrolides and mortality in critically ill patients with community-acquired pneumonia: a systematic review and meta-analysis

OBJECTIVE

Some studies suggest better outcomes with macrolide therapy for critically ill patients with community-acquired pneumonia. To further explore this, we performed a systematic review of studies with mortality endpoints that compared macrolide therapy with other regimens in critically ill patients with community-acquired pneumonia.

DATA SOURCES

Studies were identified via electronic databases, grey literature, and conference proceedings through May 2013.

STUDY SELECTION

Using prespecified criteria, two reviewers selected studies; studies of outpatients and hospitalized noncritically ill patients were excluded.

DATA EXTRACTION

Two reviewers extracted data and evaluated bias using the Newcastle-Ottawa Scale. Random effects models were used to generate pooled risk ratios and evaluate heterogeneity (I).

DATA SYNTHESIS

Twenty-eight observational studies (no randomized control trials) were included. Average age ranged from 58 to 78 years and 14-49% were women. In our primary analysis of 9,850 patients, macrolide use was associated with statistically significant lower mortality compared with nonmacrolides (21% [846 of 4,036 patients] vs 24% [1,369 of 5,814]; risk ratio, 0.82; 95% CI, 0.70-0.97; p = 0.02; I = 63%). When macrolide monotherapy was excluded, the macrolide mortality benefit was maintained (21% [737 of 3,447 patients] vs 23% [1,245 of 5,425]; risk ratio, 0.84; 95% CI, 0.71-1.00; p = 0.05; I = 60%). When broadly guideline-concordant regimens were compared, there was a trend to improved mortality and heterogeneity was reduced (20% [511 of 2,561 patients] mortality with beta-lactam/macrolide therapy vs 23% [386 of 1,680] with beta-lactam/fluoroquinolone; risk ratio, 0.83; 95% CI, 0.67-1.03; p = 0.09; I = 25%). When adjusted risk estimates were pooled from eight studies, macrolide therapy was still associated with a significant reduction in mortality (risk ratio, 0.75; 95% CI, 0.58-0.96; p = 0.02; I = 57%).

CONCLUSIONS

In observational studies of almost 10,000 critically ill patients with community-acquired pneumonia, macrolide use was associated with a significant 18% relative (3% absolute) reduction in mortality compared with nonmacrolide therapies. After pooling data from studies that provided adjusted risk estimates, an even larger mortality reduction was observed. These results suggest that macrolides be considered first-line combination treatment in critically ill patients with community-acquired pneumonia and support current guidelines.

β-Lactam/macrolide dual therapy versus β-lactam monotherapy for the treatment of community-acquired pneumonia in adults: a systematic review and meta-analysis

OBJECTIVES

Several studies have compared the clinical effect of β-lactam/macrolide (BLM) dual therapy versus β-lactam (BL) monotherapy in community-acquired pneumonia (CAP) patients. However, the results remain controversial. Thus, we did this meta-analysis to determine which treatment was more effective.

METHODS

Databases comprising PubMed, Embase and the Cochrane Register of Controlled Trials were searched to find relevant studies. The primary outcome was mortality. The Newcastle-Ottawa scale was used to evaluate the methodological quality of included studies. Multivariable-adjusted ORs with 95% CIs were pooled in the random effects model.

RESULTS

Four prospective cohort studies and 12 retrospective cohort studies were included (n = 42 942). Compared with BL monotherapy, BLM dual therapy was significantly associated with reduced mortality (adjusted OR 0.67, 95% CI 0.61-0.73, P < 0.001, I(2) = 3%). Subsequent subgroup analyses confirmed that BLM dual therapy was statistically superior to BL monotherapy in reduction of mortality. Sensitivity analyses strengthened the validity of the results.

CONCLUSIONS

In comparison with BL monotherapy, BLM dual therapy might reduce mortality risk in patients with CAP. Because this finding is based on observational studies, randomized controlled trials are required to demonstrate the usefulness of BLM dual therapy in the treatment of CAP.

Epidemiology and outcome of severe pneumococcal pneumonia admitted to intensive care unit: a multicenter study

INTRODUCTION

Community-acquired pneumonia (CAP) account for a high proportion of ICU admissions, with Streptococcus pneumoniae being the main pathogen responsible for these infections. However, little is known on the clinical features and outcomes of ICU patients with pneumococcal pneumonia. The aims of this study were to provide epidemiological data and to determine risk factors of mortality in patients admitted to ICU for severe S. pneumoniae CAP.

METHODS

We performed a retrospective review of two prospectively-acquired multicentre ICU databases (2001-2008). Patients admitted for management of severe pneumococcal CAP were enrolled if they met the 2001 American Thoracic Society criteria for severe pneumonia, had life-threatening organ failure and had a positive microbiological sample for S. pneumoniae. Patients with bronchitis, aspiration pneumonia or with non-pulmonary pneumococcal infections were excluded.

RESULTS

Two hundred and twenty two patients were included, with a median SAPS II score reaching 47 [36-64]. Acute respiratory failure (n = 154) and septic shock (n = 54) were their most frequent causes of ICU admission. Septic shock occurred in 170 patients (77%) and mechanical ventilation was required in 186 patients (84%); renal replacement therapy was initiated in 70 patients (32%). Bacteraemia was diagnosed in 101 patients. The prevalence of S. pneumoniae strains with decreased susceptibility to penicillin was 39.7%. Although antibiotherapy was adequate in 92.3% of cases, hospital mortality reached 28.8%. In multivariate analysis, independent risk factors for mortality were age (OR 1.05 (95% CI: 1.02-1.08)), male sex (OR 2.83 (95% CI: 1.16-6.91)) and renal replacement therapy (OR 3.78 (95% CI: 1.71-8.36)). Co-morbidities, macrolide administration, concomitant bacteremia or penicillin susceptibility did not influence outcome.

CONCLUSIONS

In ICU, mortality of pneumococcal CAP remains high despite adequate antimicrobial treatment. Baseline demographic data and renal replacement therapy have a major impact on adverse outcome.

Treatment with anti-inflammatory drugs in community-acquired pneumonia

Pneumonia exhibits a broad range of severity, from mildly symptomatic at one end to fulminant septic shock and death at the other. Although an adequate inflammatory response is necessary for the clearance of microorganisms, excessive inflammation can lead to ongoing local and systemic damage. Because of this extended inflammatory response despite appropriate antibiotic therapy, as well as increasing antibiotic resistance, adjuvant therapy for pneumonia that can favourably modify the immune response has become an increasingly relevant approach to improve prognosis. Different adjuvant treatment options for pneumonia have recently been proposed. Promising treatment options include corticosteroids, statins, macrolides and Toll-like receptor antagonists. The aim of this review is to summarize the inflammatory response during pneumonia and discuss the current knowledge and future perspectives regarding the anti-inflammatory treatment options for patients with pneumonia.

Epidemiology, microbiology, and treatment considerations for bacterial pneumonia complicating influenza

Post-influenza bacterial pneumonia is a major cause of morbidity and mortality associated with both seasonal and pandemic influenza virus illness. However, despite much interest in influenza and its complications in recent years, good clinical trial data to inform clinicians in their assessment of treatment options are scant. This paucity of evidence needs to be addressed urgently in order to improve guidance on the management of post-influenza bacterial pneumonia. The objectives of the current article are to evaluate the emergence of the 2009 H1N1 influenza pandemic and use this information as background for an in-depth review of the epidemiology of bacterial pneumonia complicating influenza, to review the bacterial pathogens most likely to be associated with post-influenza bacterial pneumonia, and to discuss treatment considerations in these patients. When determining optimal management approaches, both antiviral and antibacterial agents should be considered, and their selection should be based upon a clear understanding of how their mechanisms of action intervene in the pathogenesis of post-influenza acute bacterial pneumonia.

An audit of pneumococcal and hepatitis vaccination in an outpatient HIV clinic

Background HIV-positive adults are at risk of vaccine preventable infections including Streptococcus pneumoniae, hepatitis A virus (HAV) and hepatitis B virus (HBV). Uptake of immunisations in HIV patients is suboptimal despite evidence of efficacy. Methods: An audit was made of the vaccination records in 200 adult HIV-positive regular clinic attendees, with a CD4+ count >200 cells μL–1. Results: Medical records or laboratory data revealed that 10% had been vaccinated against S. pneumoniae; 74% were immune or immunised against HAV; 40% had evidence of natural infection with HBV and 84% of nonimmune patients had been vaccinated. Conclusions: Strategies to improve vaccine uptake are required.

Infection in the critically ill--questions we should be asking

Best practice in infection control and management in the critically ill continues to generate considerable debate. The wide variation in current practice is witness to this continuing uncertainty. In large part this is due to the lack of a decent evidence base and to an over-reliance on deep-set dogma. Data that go against the grain are often conveniently overlooked and political imperatives frequently supervene. This article highlights some of these discrepancies and argues for a more balanced, scientific approach. In this time of financial restraint, we need to identify true priorities from both health and economic perspectives, and to see what practices can safely and effectively be modified or abandoned.

Death or survival from invasive pneumococcal disease in Scotland: associations with serogroups and multilocus sequence types

We describe associations between death from invasive pneumococcal disease (IPD) and particular serogroups and sequence types (STs) determined by multilocus sequence typing (MLST) using data from Scotland. All IPD episodes where blood or cerebrospinal fluid (CSF) culture isolates were referred to the Scottish Haemophilus, Legionella, Meningococcal and Pneumococcal Reference Laboratory (SHLMPRL) from January 1992 to February 2007 were matched to death certification records by the General Register Office for Scotland. This represented 5959 patients. The median number of IPD cases in Scotland each year was 292. Deaths, from any cause, within 30 days of pneumococcal culture from blood or CSF were considered to have IPD as a contributing factor. Eight hundred and thirty-three patients died within 30 days of culture of Streptococcus pneumoniae from blood or CSF [13.95 %; 95 % confidence interval (13.10, 14.80)]. The highest death rates were in patients over the age of 75. Serotyping data exist for all years but MLST data were only available from 2001 onward. The risk ratio of dying from infection due to particular serogroups or STs compared to dying from IPD due to all other serogroups or STs was calculated. Fisher’s exact test with Bonferroni adjustment for multiple testing was used. Age adjustment was accomplished using the Cochran–Mantel–Haenszel test and 95 % confidence intervals were reported. Serogroups 3, 11 and 16 have increased probability of causing fatal IPD in Scotland while serogroup 1 IPD has a reduced probability of causing death. None of the 20 most common STs were significantly associated with death within 30 days of pneumococcal culture, after age adjustment. We conclude that there is a stronger association between a fatal outcome and pneumococcal capsular serogroup than there is between a fatal outcome and ST.

A survival benefit of combination antibiotic therapy for serious infections associated with sepsis and septic shock is contingent only on the risk of death: a meta-analytic/meta-regression study

OBJECTIVE

To assess whether a potential benefit with combination antibiotic therapy is restricted to the most critically ill subset of patients, particularly those with septic shock.

DATA SOURCES

OVID MEDLINE (1950-October 2009), EMBASE (1980-October 2009), the Cochrane Central Register of Controlled Trials (to third quarter 2009), the ClinicalTrial.gov database, and the SCOPUS database.

STUDY SELECTION

Randomized or observational studies of antimicrobial therapy of serious bacterial infections potentially associated with sepsis or septic shock. Fifty studies met entry criteria.

DATA EXTRACTION

Study design, mortality/clinical response, and other variables were extracted independently by two reviewers. When possible, study datasets were split into mutually exclusive groups with and without shock or critical illness.

DATA SYNTHESIS

Although a pooled odds ratio indicated no overall mortality/clinical response benefit with combination therapy (odds ratio, 0.856; 95% confidence interval, 0.71-1.03; p = .0943; I = 45.1%), stratification of datasets by monotherapy mortality risk demonstrated substantial benefit in the most severely ill subset (monotherapy risk of death >25%; odds ratio of death, 0.51; 95% confidence interval, 0.41-0.64; I = 8.6%). Of those datasets that could be stratified by the presence of shock/critical illness, the more severely ill group consistently demonstrated increased efficacy of a combination therapy strategy (odds ratio, 0.49; 95% confidence interval, 0.35-0.70; p < .0001; I = 0%). An increased risk of death was found in low-risk patients (risk of death <or=15% in the monotherapy arm) exposed to combination therapy (odds ratio, 1.53; 95% confidence interval, 1.16-2.03; p = .003; I = 8.2%). Meta-regression indicated that efficacy of combination therapy was dependent only on the risk of death in the monotherapy group.

CONCLUSION

Combination antibiotic therapy improves survival and clinical response of high-risk, life-threatening infections, particularly those associated with septic shock but may be detrimental to low-risk patients.

Impact of antibiotic therapy on systemic cytokine expression in pneumococcal pneumonia

The aim of this study was to compare the evolution of systemic cytokine levels over time in patients with pneumococal pneumonia treated either with β-lactam monotherapy or with combination therapy (β-lactam plus fluoroquinolone). Prospective observational study of hospitalized non-immunocompromised adults with PP. Concentrations of IL-6, IL-8, IL-10, and TNF-α were determined on days 0, 1, 2, 3, 5, and 7. Patients on β-lactam monotherapy were compared with those receiving combination therapy. Fifty-two patients were enrolled in the study. Concentrations of IL-6, IL-8, and IL-10 decreased rapidly in the first days after admission, in accordance with the mean time to defervescence. High levels of IL-6 were found in patients with the worst outcomes, measured by the need for intensive care unit admission and mortality. No major differences in demographic or clinical characteristics or severity of disease were found between patients treated with β-lactam monotherapy and those treated with combination therapy. IL-6 levels fell more rapidly in patients with combination therapy in the first 48 h (p = 0.016). Our data suggest that systemic expression of IL-6 production in patients with PP correlates with prognosis. Initial combination antibiotic therapy produces a faster decrease in this cytokine in the first 48 h.

Community acquired bacterial pneumonia

IMPORTANCE OF THE FIELD

Community-acquired pneumonia (CAP) is a common and potentially life-threatening illness that continues to be a major medical problem. Among infectious diseases, CAP is the leading cause of death in the world and is associated with a substantial economic burden to health are systems around the globe.

AREAS COVERED IN THIS REVIEW

Recently identified clinical and biochemical tools promise to improve the assessment of CAP severity. Various prognostic scoring systems and predictive biomarkers have been proposed as tools to aid clinicians in key management decisions. This review provides a summary of current evidence about the use of prognostic scoring systems and biomarkers in the management of patients presenting with CAP. According to the existing guidelines, until more accurate and rapid diagnostic methods are available, the initial treatment for most patients with CAP will remain empirical. Some novel antibiotic and nonantibiotic therapies have recently been tested; some empirical antimicrobial regimens are still being debated. This review summarizes the recent advances in the field of therapy and novel approaches. We searched PubMed for English-language references published from 1997 to 2009 using combinations of the following terms: 'community acquired pneumonia', 'community acquired bacterial pneumonia', 'therapy', 'antibiotics', 'antimicrobials', 'prognostic scoring systems', 'biomarkers', 'diagnostic testing', 'guidelines' 'etiological diagnosis'.

WHAT THE READER WILL GAIN

A thorough description about recent advances in the field of therapy and novel approaches of CAP, as well as a summary of current evidence about the use of prognostic scoring systems and biomarkers in the management of patients presenting with CAP, is presented.

TAKE HOME MESSAGE

Recent developments have made significant contributions to the management of CAP patients. However, various hot topics remain open and urgently require prospective studies in order to optimize the outcomes of CAP.

Determinants of outcome in patients with bacteraemic pneumococcal pneumonia: importance of early adequate treatment

We set out to determine the factors influencing mortality in 125 adult patients with bacteraemic pneumococcal community-acquired pneumonia (CAP), assessing the impact on outcomes of early adequate therapy in particular. Presumed prognostic factors with p < 0.1 in the unadjusted model were subjected to multivariate Cox regression analysis, with in-hospital and 90-day mortalities as the dependent variables. A time period of >4 h from admission to start of adequate antibiotic treatment (adjusted hazard ratio (aHR) 2.62, 95% confidence interval (CI) 1.06-6.45; p =0.037) and severe sepsis or septic shock (aHR 5.06, 95% CI 1.63-15.71; p = 0.005) were independently associated with in-hospital mortality. Variables associated with 90-day mortality were Charlson comorbidity index (aHR 1.17, 95% CI 1.02-1.34; p = 0.018), severe sepsis or septic shock (aHR 3.03, 95% CI 1.22-7.51; p = 0.016) and delay of adequate antibiotic therapy >4 h (aHR 2.21, 95% CI 1.01-4.86; p = 0.048). The use of combination therapy was not included in these models but was a protective factor for delayed adequate therapy (aHR 0.53, 95% CI 0.29-0.95; p = 0.033). Administration of adequate antimicrobial therapy within 4 h of arrival is a critical determinant of survival in patients with bacteraemic pneumococcal CAP.

[Bacterial infections in critically ill patients: review of studies published between 2006 and 2008]

A systematic revision of medical publications between 2006 and 2008 regarding bacterial infections that affect the critical patients was performed. Four subjects were selected: Community-acquired pneumonia, ventilator-associated pneumonia, catheter-related bloodstream infection and new antimicrobial treatments. When dealing with community-acquired pneumonia and due to the absence of completely reliable standards, it is necessary to follow the locally adapted guidelines of clinical practice, to identify patients related to the health-care system and admit patients to the ICU in accordance with the criteria. Regarding the etiological diagnosis of ventilator-associated pneumonia, any microbiological information available must be used. Due to the risk of multidrug bacteria, combined empiric therapy should be initiated immediately and then mono-therapy adjusted to the antibiogram should be established. Already established measures for mechanical ventilation associated pneumonia and catheter-related bacteriemias, which have been effective, should be implemented. The empirical treatment of catheter-related bacteremia must be directed towards the most probable pathogens according to the puncture site. The most recently sold antibiotics are basically directed towards multidrug gram positive resistant bacteria. However, for the treatment of gram negative resistant bacilli, the use of the new antimicrobials must be combined with a new evaluation of the antibiotics that have been used for years and the possibility of choosing different administration forms.

Bacteraemic pneumococcal pneumonia in COPD patients: better outcomes than expected

The purpose of the study was to compare the clinical characteristics and outcomes of bacteraemic pneumococcal pneumonia (BPP) in chronic obstructive pulmonary disease (COPD) and non-COPD patients. A case-control study was conducted. Cases were any adult with BPP and forced expiratory volume in 1 second (FEV(1)) <80% and FEV(1)/forced expiratory vital capacity (FVC) <70%. Controls were patients with BPP without clinical diagnosis of COPD matched 1:2 by age, gender and date of isolation. Variables included co-morbidities, serotypes, pneumonia severity index (PSI), treatment and mortality. There were 45 cases and 90 controls. No significant differences were found in Charlson scores, antibiotic treatment, serotype distribution and severity. Malignancy, shock and mechanical ventilation were less frequent in COPD patients. One patient died vs 14 controls (p = 0.02). In univariate analysis, shock, multilobar involvement, Charlson score, heart failure and absence of COPD were associated with mortality. After adjustment for the presence of shock there were no differences in mortality. BPP presents less frequently with shock and has a lower mortality rate in COPD patients than in non-COPD patients.

Medical resource utilization among community-acquired pneumonia patients initially treated with levofloxacin 750 mg daily versus ceftriaxone 1000 mg plus azithromycin 500 mg daily: a US-based study

OBJECTIVE

The 2007 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines recommend that community-acquired pneumonia (CAP) patients admitted to hospital wards initially receive respiratory fluoroquinolone monotherapy or beta-lactam plus macrolide combination therapy. There is little evidence as to which regimen is preferred, or if differences in medical resource utilization exist between therapies. Thus, the authors compared length of hospital stay (LOS) and length of intravenous antibiotic therapy (LOIV) for patients who received initial levofloxacin 750 mg daily versus ceftriaxone 1000 mg plus azithromycin 500 mg daily ('combination therapy').

RESEARCH DESIGN AND METHODS

Adult hospital CAP cases from January 2005 to December 2007 were identified by principal discharge diagnosis code. Patients with a chest infiltrate and medical notes indicative of CAP were included. Direct intensive care unit admits and healthcare-associated cases were excluded. A propensity score technique was used to balance characteristics associated with initial antimicrobial therapy using multivariable regression to derive the scores. Propensity score categories, defined as propensity score quintiles, rather than propensity scores themselves, were used in the least squares regression model to assess the impact of LOS and LOIV.

RESULTS

A total of 495 patients from six hospitals met study criteria. Of these, 313 (63%) received levofloxacin and 182 (37%) received combination therapy. Groups were similar with respect to age, sex, most comorbidities, presenting signs and symptoms, and Pneumonia Severity Index (PSI) risk class. Patients on combination therapy were more likely to have heart failure and receive pre-admission antibiotics. Adjusted least squares mean (+/-SE) LOS and LOIV were shorter with levofloxacin versus combination therapy: LOS, 4.6 +/- 0.17 vs. 5.4 +/- 0.22 days, p < 0.01; and LOIV, 3.6 +/- 0.17 vs. 4.8 +/- 0.21 days, p < 0.01. Results for PSI risk class III or IV patients were: LOS, 5.0 +/- 0.30 vs. 5.9 +/- 0.37 days, p = 0.07; and LOIV, 3.7 +/- 0.33 vs. 5.2 +/- 0.39 days, p < 0.01. Due to the retrospective study design, limited sample size, and scope (single health-network), the authors encourage replication of this study in other data sources.

CONCLUSIONS

Given the LOS and LOIV reductions of 0.8 and 1.2 days, respectively, utilization of levofloxacin 750 mg daily for CAP patients admitted to the medical floor has the potential to result in substantial cost savings for US hospitals.

The impact on community acquired pneumonia empirical therapy of diagnostic bronchoscopic techniques

The aim of the present study was to examine the modification of initial empirical treatment based on the microbiological results of bronchoscopic techniques after comparing the diagnostic yield of protected specimen brush (PSB) and bronchoalveolar lavage (BAL) in the immunocompetent patient with community acquired pneumonia (CAP) with results obtained from conventional sputum cultures. 88 patients with presumptive diagnosis of CAP necessitating hospitalization were prospectively studied. Fibreoptic bronchoscopy with quantitative PSB and BAL cultures for common pathogens, mycobacteria and fungi was performed. Conventional sputum cultures were also obtained. PSB and BAL quantitative cultures added 26.1% and 36.4%, respectively, more microbiological documentation for CAP compared to conventional sputum cultures (p < 0.0001). Gram staining was indicative of the pathogen mostly in cases where Streptococcus pneumoniae was isolated, which was also the most frequently isolated pathogen (19.3%), followed by Haemophilus influenzae (9%). M. tuberculosis was isolated in 6.8% of patients. Modification of treatment ensued in 27.3% of patients because of the application of the cultures of sputum and invasive technique. PSB and BAL added significant information to the aetiological diagnosis of hospitalized immunocompetent patients with CAP.

Pneumococcal antimicrobial resistance: therapeutic strategy and management in community-acquired pneumonia

Streptococcus pneumoniae has been consistently shown to represent the most frequent causative agent of community-acquired pneumonia (CAP) and pneumococcal antibiotic resistance towards different families of antibiotics continues to be a much-debated issue. Microbial resistance causes a great deal of confusion in choosing an empirical treatment for pneumonia and this makes it necessary to know which factors actually determine the real impact of antimicrobial resistance on the outcome of pneumococcal infections. Several different aspects have to be taken into account when analyzing this matter, such as the study design, the condition of the patient at the time of diagnosis, the choice of the initial antimicrobial regimen (combination or monotherapy) and the pharmacokinetic/pharmacodynamic variables of the chosen antibiotic. It is generally accepted that in the treatment of beta-lactam-resistant pneumococcal infections, the use of standard antipneumococcal beta-lactam agents is unlikely to impact negatively on the outcome of CAP when appropriate agents are given in sufficient doses. As a general rule, for infections with penicillin-sensitive strains, penicillin or an aminopenicillin in a standard dosage will be effective; in the cases of strains with intermediate resistance, beta-lactam agents are still considered appropriate treatment although higher dosages are recommended; finally, infections with isolates of high-level penicillin resistance should be treated with alternative agents such as the third-generation cephalosporins or the new antipneumococcal fluoroquinolones. In areas of high prevalence of high-level macrolide resistance, empirical monotherapy with a macrolide is not optimal for the treatment of hospitalised patients with moderate or moderately-severe CAP. Fluoroquinolones are considered to be excellent antibiotics in the treatment of pneumococcal CAP in adults, but their general recommendation has been withheld due to fears of a widespread development of resistance. Most international guidelines recommend combination therapy (beta-lactam plus a macrolide) for the treatment of hospitalised patients with CAP.

Multidrug-resistant Streptococcus pneumoniae infections: current and future therapeutic options

Antibacterial resistance in Streptococcus pneumoniae is increasing worldwide, affecting principally beta-lactams and macrolides (prevalence ranging between approximately 1% and 90% depending on the geographical area). Fluoroquinolone resistance has also started to emerge in countries with high level of antibacterial resistance and consumption. Of more concern, 40% of pneumococci display multi-drug resistant phenotypes, again with highly variable prevalence among countries. Infections caused by resistant pneumococci can still be treated using first-line antibacterials (beta-lactams), provided the dosage is optimised to cover less susceptible strains. Macrolides can no longer be used as monotherapy, but are combined with beta-lactams to cover intracellular bacteria. Ketolides could be an alternative, but toxicity issues have recently restricted the use of telithromycin in the US. The so-called respiratory fluoroquinolones offer the advantages of easy administration and a spectrum covering extracellular and intracellular pathogens. However, their broad spectrum raises questions regarding the global risk of resistance selection and their safety profile is far from optimal for wide use in the community. For multi-drug resistant pneumococci, ketolides and fluoroquinolones could be considered. A large number of drugs with activity against these multi-drug resistant strains (cephalosporins, carbapenems, glycopeptides, lipopeptides, ketolides, lincosamides, oxazolidinones, glycylcyclines, quinolones, deformylase inhibitors) are currently in development. Most of them are only new derivatives in existing classes, with improved intrinsic activity or lower susceptibility to resistance mechanisms. Except for the new fluoroquinolones, these agents are also primarily targeted towards methicillin-resistant Staphylococcus aureus infections; therefore, demonstration of their clinical efficacy in the management of pneumococcal infections is still awaited.