Optimal therapy for severe pneumococcal community-acquired pneumonia

Role of PatAB Transporter in Efflux of Levofloxacin in Streptococcus pneumoniae

PatAB is an ABC bacterial transporter that facilitates the export of antibiotics and dyes. The overexpression of patAB genes conferring efflux-mediated fluoroquinolone resistance has been observed in several laboratory strains and clinical isolates of Streptococcus pneumoniae. Using transformation and whole-genome sequencing, we characterized the fluoroquinolone-resistance mechanism of one S. pneumoniae clinical isolate without mutations in the DNA topoisomerase genes. We identified the PatAB fluoroquinolone efflux-pump as the mechanism conferring a low-level resistance to ciprofloxacin (8 µg/mL) and levofloxacin (4 µg/mL). Genetic transformation experiments with different amplimers revealed that the entire patA plus the 5'-terminus of patB are required for levofloxacin-efflux. By contrast, only the upstream region of the patAB operon, plus the region coding the N-terminus of PatA containing the G39D, T43A, V48A and D100N amino acid changes, are sufficient to confer a ciprofloxacin-efflux phenotype, thus suggesting differences between fluoroquinolones in their binding and/or translocation pathways. In addition, we identified a novel single mutation responsible for the constitutive and ciprofloxacin-inducible upregulation of patAB. This mutation is predicted to destabilize the putative rho-independent transcriptional terminator located upstream of patA, increasing transcription of downstream genes. This is the first report demonstrating the role of the PatAB transporter in levofloxacin-efflux in a pneumoccocal clinical isolate.

Pneumolysin as a potential therapeutic target in severe pneumococcal disease

Acute pulmonary and cardiac injury remain significant causes of morbidity and mortality in those afflicted with severe pneumococcal disease, with the risk for early mortality often persisting several years beyond clinical recovery. Although remaining to be firmly established in the clinical setting, a considerable body of evidence, mostly derived from murine models of experimental infection, has implicated the pneumococcal, cholesterol-binding, pore-forming toxin, pneumolysin (Ply), in the pathogenesis of lung and myocardial dysfunction. Topics covered in this review include the burden of pneumococcal disease, risk factors, virulence determinants of the pneumococcus, complications of severe disease, antibiotic and adjuvant therapies, as well as the structure of Ply and the role of the toxin in disease pathogenesis. Given the increasing recognition of the clinical potential of Ply-neutralisation strategies, the remaining sections of the review are focused on updates of the types, benefits and limitations of currently available therapies which may attenuate, directly and/or indirectly, the injurious actions of Ply. These include recently described experimental therapies such as various phytochemicals and lipids, and a second group of more conventional agents the members of which remain the subject of ongoing clinical evaluation. This latter group, which is covered more extensively, encompasses macrolides, statins, corticosteroids, and platelet-targeted therapies, particularly aspirin.

Decrease in mortality in severe community-acquired pneumococcal pneumonia: impact of improving antibiotic strategies (2000-2013)

OBJECTIVE

The objective of the present study was to compare antibiotic prescribing practices and survival in the ICU for patients with pneumococcal severe community-acquired pneumonia (SCAP) between 2000 and 2013.

METHODS

This was a matched case-control study of two prospectively recorded cohorts in Europe. Eighty patients from the Community-Acquired Pneumonia en la Unidad de Cuidados Intensivos (CAPUCI) II study (case group) were matched with 80 patients from CAPUCI I (control group) based on the following: shock at admission, need of mechanical ventilation, COPD, immunosuppression, and age.

RESULTS

Demographic data were comparable in the two groups. Combined antibiotic therapy increased from 66.2% to 87.5% (P < .01), and the percentage of patients receiving the first dose of antibiotic within 3 h increased from 27.5% to 70.0% (P < .01). ICU mortality was significantly lower (OR, 0.82; 95% CI, 0.68-0.98) in cases, both in the whole population and in the subgroups of patients with shock (OR, 0.67; 95% CI, 0.50-0.89) or receiving mechanical ventilation (OR, 0.73; 95% CI, 0.55-0.96). In the multivariate analysis, ICU mortality increased in patients requiring mechanical ventilation (OR, 5.23; 95% CI, 1.60-17.17) and decreased in patients receiving early antibiotic treatment (OR, 0.36; 95% CI, 0.15-0.87) and combined therapy (OR, 0.19; 95% CI, 0.07-0.51).

CONCLUSIONS

In pneumococcal SCAP, early antibiotic prescription and use of combination therapy increased. Both were associated with improved survival.

Mortality indicators in community-acquired pneumonia requiring intensive care in Turkey

BACKGROUND

Severe community-acquired pneumonia (SCAP) is a fatal disease. This study was conducted to describe an outcome analysis of the intensive care units (ICUs) of Turkey.

METHODS

This study evaluated SCAP cases hospitalized in the ICUs of 19 different hospitals between October 2008 and January 2011. The cases of 413 patients admitted to the ICUs were retrospectively analyzed.

RESULTS

Overall 413 patients were included in the study and 129 (31.2%) died. It was found that bilateral pulmonary involvement (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.1-5.7) and CAP PIRO score (OR 2, 95% CI 1.3-2.9) were independent risk factors for a higher in-ICU mortality, while arterial hypertension (OR 0.3, 95% CI 0.1-0.9) and the application of non-invasive ventilation (OR 0.2, 95% CI 0.1-0.5) decreased mortality. No culture of any kind was obtained for 90 (22%) patients during the entire course of the hospitalization. Blood, bronchoalveolar lavage, and non-bronchoscopic lavage cultures yielded enteric Gram-negatives (n=12), followed by Staphylococcus aureus (n=10), pneumococci (n=6), and Pseudomonas aeruginosa (n=6). For 22% of the patients, none of the culture methods were applied.

CONCLUSIONS

SCAP requiring ICU admission is associated with considerable mortality for ICU patients. Increased awareness appears essential for the microbiological diagnosis of this disease.

Brazilian guidelines for community-acquired pneumonia in immunocompetent adults - 2009

Community-acquired pneumonia continues to be the acute infectious disease that has the greatest medical and social impact regarding morbidity and treatment costs. Children and the elderly are more susceptible to severe complications, thereby justifying the fact that the prevention measures adopted have focused on these age brackets. Despite the advances in the knowledge of etiology and physiopathology, as well as the improvement in preliminary clinical and therapeutic methods, various questions merit further investigation. This is due to the clinical, social, demographical and structural diversity, which cannot be fully predicted. Consequently, guidelines are published in order to compile the most recent knowledge in a systematic way and to promote the rational use of that knowledge in medical practice. Therefore, guidelines are not a rigid set of rules that must be followed, but first and foremost a tool to be used in a critical way, bearing in mind the variability of biological and human responses within their individual and social contexts. This document represents the conclusion of a detailed discussion among the members of the Scientific Board and Respiratory Infection Committee of the Brazilian Thoracic Association. The objective of the work group was to present relevant topics in order to update the previous guidelines. We attempted to avoid the repetition of consensual concepts. The principal objective of creating this document was to present a compilation of the recent advances published in the literature and, consequently, to contribute to improving the quality of the medical care provided to immunocompetent adult patients with community-acquired pneumonia.

Therapy for pneumococcal bacteremia: monotherapy or combination therapy?

PURPOSE OF REVIEW

The issue of whether the outcome of bacteremic pneumococcal infections is improved with the use of combination antibiotic therapy versus monotherapy is still not resolved. This review highlights recent studies that have addressed this issue.

RECENT FINDINGS

Some studies have indicated benefit of combination antibiotic therapy in severely ill patients with community-acquired pneumonia of all-cause. Conversely, in less severely ill hospitalized patients, fluoroquinolone monotherapy was as effective as fluoroquinolone combination regimens and a propensity analysis failed to show benefit of beta-lactam/macrolide combination over beta-lactam monotherapy. Studies across the world have shown a more favorable outcome in patients with community-acquired pneumonia treated with guideline-compliant therapy, mostly beta-lactam/macrolide combination regimens. The only recent study of patients with bacteremic pneumococcal pneumonia failed, however, to show benefit of combination therapy. A large number of investigations have yielded observations that address possible mechanisms by which combination therapy may have benefit, investigating issues such as cover for atypical pathogens, attenuation of pneumococcal virulence factors, and anti-inflammatory activity of the macrolide group of antibiotics.

SUMMARY

Despite a number of recent studies, the definitive decision regarding the need for combination antibiotic therapy for the effective management of bacteremic pneumococcal infections has not yet been formally resolved.

Mortality in ICU patients with bacterial community-acquired pneumonia: when antibiotics are not enough

BACKGROUND

It remains uncertain why immunocompetent patients with bacterial community-acquired pneumonia (CAP) die, in spite of adequate antibiotics.

METHODS

This is a secondary analysis of the CAPUCI database which was a prospective observational multicentre study. Two hundred and twelve immunocompetent patients admitted to 33 Spanish ICUs for CAP were analyzed. Comparisons were made for lifestyle risk factors, comorbidities and severity of illness. ICU mortality was the principal outcome variable.

RESULTS

Bacteremic CAP (43.3 vs. 21.1%) and empyema (11.5 vs. 2.2%) were more frequent (P < 0.05) in patients with Streptococcus pneumoniae CAP. Higher rates of adequate empiric therapy (95.8 vs. 75.5%, P < 0.05) were observed in patients with S. pneumoniae CAP. Patients with non-pneumococcal CAP experienced more shock (66.7 vs. 50.8%, P < 0.05), and need for mechanical ventilation (83.3 vs. 61.5%, P < 0.05). ICU mortality was 20.7 and 28% [OR 1.49(0.74-2.98)] among immunocompetent patients with S. pneumoniae (n = 122) and non-pneumococci (n = 90), in spite of initial adequate antibiotic. Multivariable regression analysis in these 184 immunocompetent patients with adequate empirical antibiotic treatment identified the following variables as independently associated with mortality: shock (HR 13.03); acute renal failure (HR 4.79), and APACHE II score higher than 24 (HR 2.22).

CONCLUSIONS

Mortality remains unacceptably high in immunocompetent patients admitted to the ICU with bacterial pneumonia, despite adequate initial antibiotics and comorbidities management. Patients with shock, acute renal failure and APACHE II score higher than 24 should be considered for inclusion in trials of adjunctive therapy in order to improve CAP survival.

Combination antibiotic therapy improves survival in patients with community-acquired pneumonia and shock*

OBJECTIVE

To assess whether combination antibiotic therapy improves outcome of severe community-acquired pneumonia in the subset of patients with shock.

DESIGN

Secondary analysis of a prospective observational, cohort study.

SETTING

Thirty-three intensive care units (ICUs) in Spain.

PATIENTS

Patients were 529 adults with community-acquired pneumonia requiring ICU admission.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Two hundred and seventy (51%) patients required vasoactive drugs and were categorized as having shock. The effects of combination antibiotic therapy and monotherapy on survival were compared using univariate analysis and a Cox regression model. The adjusted 28-day in-ICU mortality was similar (p = .99) for combination antibiotic therapy and monotherapy in the absence of shock. However, in patients with shock, combination antibiotic therapy was associated with significantly higher adjusted 28-day in-ICU survival (hazard ratio, 1.69; 95% confidence interval, 1.09-2.60; p = .01) in a Cox hazard regression model. Even when monotherapy was appropriate, it achieved a lower 28-day in-ICU survival than an adequate antibiotic combination (hazard ratio, 1.64; 95% confidence interval, 1.01-2.64).

CONCLUSIONS

Combination antibiotic therapy does not seem to increase ICU survival in all patients with severe community-acquired pneumonia. However, in the subset of patients with shock, combination antibiotic therapy improves survival rates.

Current Concepts of Severe Pneumococcal Community-acquired Pneumonia

Community-acquired pneumonia (CAP) is a major health problem, even in developed countries, being the leading cause of death due to infectious diseases in the USA [1]. CAP has a wide clinical spectrum of severity: up to 80% of patients are successfully managed in primary care, but 1 % of patients with CAP are classified as having severe disease, needing intensive care unit (ICU) admission, with 20–50% dying despite all available support and treatment options being utilized. Streptococcus pneumoniae is the most common cause of CAP, enclosing the subset group of patients having severe disease [2]. Moreover, bacteremia is not uncommon in pneumococcal CAP (20%) and has been associated with increased severity and mortality compared with non-bacteremic pneumonia [3].

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this new feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest will be abstracted monthly regarding a broad scope of topics.