Principles of antibiotic treatment of community-acquired pneumonia in the outpatient setting

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.

Community-Acquired Pneumonia: A Focused Review

Community-acquired pneumonia (CAP) is a common cause for admission to the hospital and contributes significantly to patient morbidity and healthcare cost. We present a review of the epidemiology, pathophysiology, risk factors, symptoms, diagnosis, presentations, risk-stratification, markers, and management of CAP in the United States (US). The overall incidence of CAP is 16 to 23 cases per 1000 persons per year, and the rate increases with age. Some of the risk factors for CAP include comorbidities such as, chronic obstructive pulmonary disease (COPD), asthma, and heart failure. CAP symptoms vary, and typically include productive cough, dyspnea, pleuritic pain, abnormal vital signs (e.g., fever, tachycardia), and abnormal lung examination findings. A diagnosis can be made by radiography, which has the additional benefit of helping to identify patterns associated with typical and atypical CAP. There are risk-stratification calculators that can be used routinely by physicians to triage patients, and to determine adequate management. The Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) developed the Pneumonia Severity Index (PSI) which incorporates 20 risk factors to place patients into 5 classes correlated with mortality risk. In addition, the British Thoracic Society (BTS) established the original severity score CURB (confusion, uremia, respiratory rate, low blood pressure) to identify patients with CAP who may be candidates for outpatient vs. inpatient treatment. Inflammatory markers, such as procalcitonin (PCT), can be used to guide management throughout hospital stay. Antibiotic coverage will vary depending on whether outpatient vs. inpatient management is required.

Short-course versus long-course therapy of the same antibiotic for community-acquired pneumonia in adolescent and adult outpatients

BACKGROUND

Community-acquired pneumonia (CAP) is a lung infection that can be acquired during day-to-day activities in the community (not while receiving care in a hospital). Community-acquired pneumonia poses a significant public health burden in terms of mortality, morbidity, and costs. Shorter antibiotic courses for CAP may limit treatment costs and adverse effects, but the optimal duration of antibiotic treatment is uncertain.

OBJECTIVES

To evaluate the efficacy and safety of short-course versus longer-course treatment with the same antibiotic at the same daily dosage for CAP in non-hospitalised adolescents and adults (outpatients). We planned to investigate non-inferiority of short-course versus longer-term course treatment for efficacy outcomes, and superiority of short-course treatment for safety outcomes.

SEARCH METHODS

We searched CENTRAL, which contains the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, five other databases, and three trials registers on 28 September 2017 together with conference proceedings, reference checking, and contact with experts and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short- and long-courses of the same antibiotic for CAP in adolescent and adult outpatients.

DATA COLLECTION AND ANALYSIS

We planned to use standard Cochrane methods.

MAIN RESULTS

Our searches identified 5260 records. We did not identify any RCTs that compared short- and longer-courses of the same antibiotic for the treatment of adolescents and adult outpatients with CAP.We excluded two RCTs that compared short courses (five compared to seven days) of the same antibiotic at the same daily dose because they evaluated antibiotics (gemifloxacin and telithromycin) not commonly used in practice for the treatment of CAP. In particular, gemifloxacin is no longer approved for the treatment of mild-to-moderate CAP due to its questionable risk-benefit balance, and reported adverse effects. Moreover, the safety profile of telithromycin is also cause for concern.We found one ongoing study that we will assess for inclusion in future updates of the review.

AUTHORS' CONCLUSIONS

We found no eligible RCTs that studied a short-course of antibiotic compared to a longer-course (with the same antibiotic at the same daily dosage) for CAP in adolescent and adult outpatients. The effects of antibiotic therapy duration for CAP in adolescent and adult outpatients remains unclear.

Antibiotics for treating community-acquired pneumonia in people with sickle cell disease

BACKGROUND

As a consequence of their condition, people with sickle cell disease are at high risk of developing an acute infection of the pulmonary parenchyma called community-acquired pneumonia. Many different bacteria can cause this infection and antibiotic treatment is generally needed to resolve it. There is no standardized approach to antibiotic therapy and treatment is likely to vary from country to country. Thus, there is a need to identify the efficacy and safety of different antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. This is an update of a previously published Cochrane Review.

OBJECTIVES

To determine the efficacy and safety of the antibiotic treatment approaches (monotherapy or combined) for people with sickle cell disease suffering from community-acquired pneumonia.

SEARCH METHODS

We searched The Group's Haemoglobinopathies Trials Register (01 September 2016), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched LILACS (1982 to 01 September 2016), African Index Medicus (1982 to 20 October 2016) and WHO ICT Registry (20 October 2016).

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

We intended to summarise data by standard Cochrane methodologies, but no eligible randomized controlled trials were identified.

MAIN RESULTS

We were unable to find any randomized controlled trials on antibiotic treatment approaches for community-acquired pneumonia in people with sickle cell disease.

AUTHORS' CONCLUSIONS

The updated review was unable to identify randomized controlled trials on efficacy and safety of the antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. Randomized controlled trials are needed to establish the optimum antibiotic treatment for this condition. The trials regarding this issue should be structured and reported according to the CONSORT statement for improving the quality of reporting of efficacy and improved reports of harms in clinical research. Triallists should consider including the following outcomes in new trials: number of days to become afebrile; mortality; onset of pain crisis or complications of sickle cell disease following community-acquired pneumonia; diagnosis; hospitalization (admission rate and length of hospital stay); respiratory failure rate; and number of participants receiving a blood transfusion.There are no trials included in the review and we have not identified any relevant trials up to September 2016. We therefore do not plan to update this review until new trials are published.

Antibiotics for treating community acquired pneumonia in people with sickle cell disease

BACKGROUND

As a consequence of their condition, people with sickle cell disease are at high risk of developing an acute infection of the pulmonary parenchyma called community-acquired pneumonia. Many different bacteria can cause this infection and antibiotic treatment is generally needed to resolve it. There is no standardized approach to antibiotic therapy and treatment is likely to vary from country to country. Thus, there is a need to identify the efficacy and safety of different antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia.

OBJECTIVES

To determine the efficacy and safety of the antibiotic treatment approaches (monotherapy or combined) for people with sickle cell disease suffering from community-acquired pneumonia.

SEARCH METHODS

We searched The Group's Haemoglobinopathies Trials Register (25 May 2012), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched LILACS (1982 to 27 April 2012), African Index Medicus (1982 to 27 April 2012) and WHO ICT Registry (27 April 2012).

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

We intended to summarise data by standard Cochrane Collaboration methodologies, but no eligible randomized controlled trials were identified.

MAIN RESULTS

We were unable to find any randomized controlled trials on antibiotic treatment approaches for community-acquired pneumonia in people with sickle cell disease.

AUTHORS' CONCLUSIONS

The updated review was unable to identify randomized controlled trials on efficacy and safety of the antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. Randomized controlled trials are needed to establish the optimum antibiotic treatment for this condition. The trials regarding this issue should be structured and reported according to the CONSORT statement for improving the quality of reporting of efficacy and improved reports of harms in clinical research. Triallists should consider including the following outcomes in new trials: number of days to become afebrile; mortality; onset of pain crisis or complications of SCD following CAP; diagnosis; hospitalisation (admission rate and length of hospital stay); respiratory failure rate; and number of participants receiving a blood transfusion.There are no trials included in the review and we have not identified any relevant trials up to May 2012. We therefore do not plan to update this review until new trials are published.

Selecting against antibiotic-resistant pathogens: optimal treatments in the presence of commensal bacteria

Using optimal control theory as the basic theoretical tool, we investigate the efficacy of different antibiotic treatment protocols in the most exacting of circumstances, described as follows. Viewing a continuous culture device as a proxy for a much more complex host organism, we first inoculate the device with a single bacterial species and deem this the 'commensal' bacterium of our host. We then force the commensal to compete for a single carbon source with a rapidly evolving and fitter 'pathogenic bacterium', the latter so-named because we wish to use a bacteriostatic antibiotic to drive the pathogen toward low population densities. Constructing a mathematical model to mimic the biology, we do so in such a way that the commensal would be eventually excluded by the pathogen if no antibiotic treatment were given to the host or if the antibiotic were over-deployed. Indeed, in our model, all fixed-dose antibiotic treatment regimens will lead to the eventual loss of the commensal from the host proxy. Despite the obvious gravity of the situation for the commensal bacterium, we show by example that it is possible to design drug deployment protocols that support the commensal and reduce the pathogen load. This may be achieved by appropriately fluctuating the concentration of drug in the environment; a result that is to be anticipated from the theory optimal control where bang-bang solutions may be interpreted as intermittent periods of either maximal and minimal drug deployment. While such 'antibiotic pulsing' is near-optimal for a wide range of treatment objectives, we also use this model to evaluate the efficacy of different antibiotic usage strategies to show that dynamically changing antimicrobial therapies may be effective in clearing a bacterial infection even when every 'static monotherapy' fails.

Fluoroquinolones in the management of community-acquired pneumonia in primary care

A literature search was conducted to evaluate the pharmacokinetic and pharmacodynamic profile of the respiratory fluoroquinolones (gemifloxacin, levofloxacin and moxifloxacin) and their efficacy and safety in the management of community-acquired pneumonia (CAP). Data show that CAP is a common presentation in primary care practice, and is associated with high rates of morbidity and mortality, particularly in the elderly. Although the causative pathogens differ depending on treatment setting and patient factors, Streptococcus pneumoniae is the primary pathogen in all treatment settings. As a class, the respiratory fluoroquinolones have a very favorable pharmacokinetic and pharmacodynamic profile. Pharmacodynamic criteria suggest that moxifloxacin and gemifloxacin are more potent against S. pneumoniae, which may have the added benefit of reducing resistance selection and enhancing bacterial eradication. The respiratory fluoroquinolones are also generally well tolerated, and are first-line options for outpatient treatment of CAP in patients with comorbidities or previous antibiotic use.

The Human Lung Microbiome

The human lower respiratory tract is considered sterile in normal healthy individuals (Flanagan et al., 2007; Speert, 2006) despite the fact that every day we breathe in multiple microorganisms present in the air and aspirate thousands of organisms from the mouth and nasopharynx. This apparent sterility is maintained by numerous interrelated components of the lung physical structures such as the mucociliary elevator and components of the innate and adaptive immune systems (discussed below) (reviewed in (Diamond et al., 2000; Gerritsen, 2000)). However, it is possible that the observed sterility might be a result of the laboratory practices applied to study the flora of the lungs. Historically, researchers faced with a set of diseases characterized by a changing and largely cryptic lung microbiome have lacked tools to study lung ecology as a whole and have concentrated on familiar, cultivatable candidate pathogens.

Healthcare utilization in community-acquired pneumonia episodes of care: a comparison across the continuum of managed care

OBJECTIVE

Compare healthcare utilization and total payments for community-acquired pneumonia (CAP) episodes-of-care among 5 health plan designs spanning the continuum of managed care.

RESEARCH DESIGN

Medical and prescription claims analysis of CAP episodes among enrollees of employer-sponsored health plans. Episode characteristics, healthcare utilization, and payments were compared across fee-for-service, Preferred Provider Organizations (PPO), point of service, partial capitation, and Health Maintenance Organizations as defined by the employers. Medstat Episode of Care Grouper Version 2.1.5 was employed to create episodes of CAP care. Categorical and continuous measures of patient and care characteristics across plan designs were compared by chi tests and one-way analysis-of-variance as appropriate. Total per-episode payments for provided services across plan designs were compared using a general linear model with a log-link function and gamma distribution.

RESULTS

Greater average patient age, episode severity, number of office visits, rate of hospitalization, length of stay, and inpatient mortality overall were found within PPO episodes compared with all other plan designs. Total episode payments controlling for age, sex, disease severity, and geography were greatest among PPO episodes and attributed largely to more office visits and longer lengths of hospital stays compared with other plan types.

CONCLUSIONS

As previously shown among other patient populations and conditions, PPO episodes of CAP are associated with greater total payments due in large part to increased resource utilization among the episodes of lowest severity.

Levofloxacin : a review of its use as a high-dose, short-course treatment for bacterial infection

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial that is the L-isomer of ofloxacin. A high-dose (750 mg) short-course (5 days) of once-daily levofloxacin is approved for use in the US in the treatment of community-acquired pneumonia (CAP), acute bacterial sinusitis (ABS), complicated urinary tract infections (UTI) and acute pyelonephritis (AP). The broad spectrum antibacterial profile of levofloxacin means that monotherapy is often a possibility in patients with CAP at times when other agents may require combination therapy, although levofloxacin can be used in combination therapy when necessary. The high-dose, short-course levofloxacin regimen maximizes its concentration-dependent bactericidal activity and may reduce the potential for resistance to emerge. In addition, this regimen lends itself to better compliance because of the shorter duration of treatment and the convenient once-daily administration schedule. Oral levofloxacin is rapidly absorbed and is bioequivalent to the intravenous formulation; importantly, patients can transition between the formulations, which results in more options in regards to the treatment regimen and the potential for patients with varying degrees of illness to be treated. Levofloxacin has good tissue penetration and an adequate concentration can be maintained in the urinary tract to treat uropathogens. Levofloxacin is generally well tolerated and has good efficacy in the treatment of patients with CAP, ABS, complicated UTI and AP. The efficacy and tolerability of levofloxacin 500 mg once daily for 10 days in patients with CAP, ABS and UTIs is well established, and the high-dose, short-course levofloxacin regimen has been shown to be noninferior to the 10-day regimen in CAP and ABS, and to have a similar tolerability profile. Similarly, the high-dose, short-course levofloxacin regimen is noninferior to ciprofloxacin in patients with complicated UTI or AP. Thus, levofloxacin is a valuable antimicrobial agent that has activity against a wide range of bacterial pathogens; however, its use should be considered carefully so that the potential for resistance selection can be minimized and its usefulness in severe infections and against a range of penicillin- and macrolide-resistant pathogens can be maintained.

Efficacy of short-course antibiotic regimens for community-acquired pneumonia: a meta-analysis

PURPOSE

There is little consensus on the most appropriate duration of antibiotic treatment for community-acquired pneumonia. The goal of this study is to systematically review randomized controlled trials comparing short-course and extended-course antibiotic regimens for community-acquired pneumonia.

METHODS

We searched MEDLINE, Embase, and CENTRAL, and reviewed reference lists from 1980 through June 2006. Studies were included if they were randomized controlled trials that compared short-course (7 days or less) versus extended-course (>7 days) antibiotic monotherapy for community-acquired pneumonia in adults. The primary outcome measure was failure to achieve clinical improvement.

RESULTS

We found 15 randomized controlled trials matching our inclusion and exclusion criteria comprising 2796 total subjects. Short-course regimens primarily studied the use of azithromycin (n=10), but trials examining beta-lactams (n=2), fluoroquinolones (n=2), and ketolides (n=1) were found as well. Of the extended-course regimens, 3 studies utilized the same antibiotic, whereas 9 involved an antibiotic of the same class. Overall, there was no difference in the risk of clinical failure between the short-course and extended-course regimens (0.89, 95% confidence interval [CI], 0.78-1.02). In addition, there were no differences in the risk of mortality (0.81, 95% CI, 0.46-1.43) or bacteriologic eradication (1.11, 95% CI, 0.76-1.62). In subgroup analyses, there was a trend toward favorable clinical efficacy for the short-course regimens in all antibiotic classes (range of relative risk, 0.88-0.94).

CONCLUSIONS

The available studies suggest that adults with mild to moderate community-acquired pneumonia can be safely and effectively treated with an antibiotic regimen of 7 days or less. Reduction in patient exposure to antibiotics may limit the increasing rates of antimicrobial drug resistance, decrease cost, and improve patient adherence and tolerability.

International classification of diseases codes showed modest sensitivity for detecting community-acquired pneumonia

OBJECTIVE

To estimate the sensitivity of International Classification of Diseases (ICD-9-CM) coding for detecting hospitalized community-acquired pneumonia and to assess possible determinants for misclassification.

STUDY DESIGN AND SETTING

Based on microbiological analysis data, 293 patients with a principal diagnosis of community-acquired pneumonia at seven hospitals in the Netherlands were assigned to three categories (pneumococcal pneumonia, pneumonia with other organism, or pneumonia with no organism specified). For these patients, the assigned principal and secondary ICD-9-CM codes in the hospital discharge record were retrieved and the corresponding sensitivity was calculated. Furthermore, pneumonia-related patient characteristics were compared between correctly and incorrectly coded subjects.

RESULTS

The overall sensitivity was 72.4% for the principal code and 79.5% for combined principal and secondary codes. For pneumococcal pneumonia (ICD-9-CM code 481) and pneumonia with specified organism (ICD-9-CM code 482-483), the sensitivities were 35% and 18.3%, respectively. Patient characteristics were not significantly different between correctly and incorrectly coded subjects except for duration of hospital stay, which correlated negatively with coding sensitivity (P=0.01).

CONCLUSION

ICD-9-CM codes showed modest sensitivity for detecting community-acquired pneumonia in hospital administrative databases, leaving at least one quarter of pneumonia cases undetected. Sensitivity decreased with longer duration of hospital stay.

Gemifloxacin once daily for 5 days versus 7 days for the treatment of community-acquired pneumonia: a randomized, multicentre, double-blind study

OBJECTIVES

Short-course therapy has been advocated for the treatment of community-acquired pneumonia (CAP). We compared the efficacy and safety of 5 and 7 day courses of gemifloxacin for outpatient treatment of mild-moderate CAP.

PATIENTS AND METHODS

In a multicentre, double-blind, parallel group study, patients were randomized to receive 320 mg of oral gemifloxacin once daily for 5 or 7 days. Over 95% of all patients in each cohort had a Fine score of <or=III. The primary efficacy endpoint was clinical cure at follow-up (days 24-30). Secondary outcomes were clinical and bacteriological responses at the end of therapy (days 7-9) and bacteriological and radiological responses at follow-up. Adverse events (AEs) were also monitored.

RESULTS

In a total of 469 per protocol (PP) patients, clinical resolution at follow-up was 95% and 92% for 5 and 7 day treatments, respectively [95% confidence interval (CI) -1.48, 7.42], indicating non-inferiority of 5 day treatment. Clinical resolution at the end of therapy was 96% for both regimens (95% CI -3.85, 3.42). Bacteriological response rates in PP patients at the end of therapy were 94% and 96% for 5 and 7 day groups, respectively (95% CI -8.27, 3.25) and 91% for both groups at follow-up (95% CI -6.89, 7.93). Radiological success in PP patients at follow-up was 98% and 93% in 5 and 7 day groups, respectively (95% CI 0.35, 7.91). Pre-therapy pathogens were identified in 242 (47.3%) patients, most commonly Streptococcus pneumoniae. Frequency of treatment-related AEs was 21% in both cohorts with discontinuation rates of 1.2% and 2% in the 5 and 7 day groups, respectively. A lower incidence of rash was observed in the 5 day cohort (0.4%) versus the 7 day cohort (2.8%) (P=0.04).

CONCLUSIONS

Gemifloxacin once daily for 5 days is not inferior to 7 days in the PP population with respect to clinical, bacteriological and radiological efficacy. Further work is needed, however, to explore whether fewer treatment days would improve patient compliance and reduce the incidence of AEs.

Clinical pharmacokinetics and gastrointestinal tolerability of a novel extended-release microsphere formulation of azithromycin

BACKGROUND AND OBJECTIVE

A novel oral, extended-release, microsphere formulation of azithromycin (AZSR) was developed to improve the gastrointestinal tolerability profile while allowing administration of an entire treatment course of azithromycin in a single dose. Several phase I clinical pharmacology studies were conducted to (i) identify a well-tolerated single-dose formulation that met a predefined exposure target; and (ii) evaluate the effect of food and antacid on the absorption of this formulation. Of these, five pivotal studies are described here.

METHODS

The pharmacokinetic profile of AZSR was compared with that of the commercially available immediate-release azithromycin formulation (AZM) in an open-label, crossover, single-dose study (Study A), and their gastrointestinal tolerability profiles were compared in an observer-blind, parallel group, single-dose study (Study B). The effects of food (a high-fat meal and a standard meal) and antacid (a single 20 mL dose of Maalox Regular Strength, containing magnesium hydroxide, aluminium hydroxide and simethicone) on the absorption of azithromycin from AZSR were evaluated in three separate open-label, crossover, single-dose studies (Studies C, D and E). Healthy adult subjects were enrolled in all five studies, and all subjects were evaluable for tolerability. The dose used for all azithromycin formulations was 2.0 g. Serum azithromycin concentrations were determined using a validated high-performance liquid chromatography/electrochemical detection method, and pharmacokinetic parameters were analysed using noncompartmental methods.

RESULTS

377 subjects received a single 2.0 g dose of azithromycin as AZSR and/or AZM in the five studies. Compared with AZM, AZSR had a slower absorption rate (57% decrease in the mean peak concentration [C(max)] and an approximate 2.5-hour delay in the time to reach C(max) [t(max)]), with a mean relative bioavailability of 82.8%, which met the predefined exposure target (at least 80% bioavailability relative to AZM). Compared with AZM, AZSR was associated with significantly lower rates of nausea and vomiting. A high-fat meal increased the mean area under the serum concentration-time curve [AUC] from time zero to 72 hours post-dose (AUC(72 h)) by 23% and increased the C(max) of azithromycin by 115%. A standard meal increased the mean C(max) by 119% but had no clinically significant effect on the AUC(72 h). AZSR appeared to be better tolerated in the fasted state than in the fed state. The AUC(72 h) and C(max) of AZSR were not significantly affected by co-administration with a single dose of antacid.

CONCLUSIONS

The extended-release microsphere formulation of azithromycin, AZSR, allows administration of an entire therapeutic course of azithromycin as a well-tolerated single 2.0 g dose. This formulation should be administered on an empty stomach and can be co-administered with antacids.

Angiotensin-converting enzyme inhibitor use and protection against pneumonia in patients with diabetes

OBJECTIVES

Because of the high risk of pneumonia in patients with diabetes, we aimed to assess the effect of angiotensin-converting enzyme (ACE) inhibitor use on the occurrence of pneumonia in a general population of patients with diabetes.

METHODS

The study population comprised all patients in the UK General Practice Research Database who had a diagnosis of diabetes (both type 1 and type 2) between 1987 and 2001. Cases were defined as patients with a first diagnosis of pneumonia. For each case, up to four controls were matched by age, gender, practice, and index date. Patients were classified as current ACE inhibitor user when the index date was between the start and end date of ACE inhibitor therapy. Conditional logistic regression analysis was used to estimate the strength of the association between ACE inhibitor use and pneumonia risk.

RESULTS

ACE inhibitors were used in 12.7% of 4719 cases and in 13.7% of 15,322 matched controls [crude odds ratio (OR)=0.92, 95% confidence interval (CI)=0.82-1.01]. After adjusting for confounding, ACE inhibitor therapy was associated with a significant reduction in pneumonia risk (adjusted OR=0.72, 95% CI=0.64-0.80). The protective association was consistent across different relevant subgroups with the strongest association in patients with a history of stroke. There was a significant dose-effect relationship (P for trend < 0.001).

CONCLUSIONS

The use of ACE inhibitors is associated with a significant reduction in pneumonia risk and, apart from blood pressure-lowering properties, may be useful in the prevention of pneumonia in patients with diabetes.

Comparative pharmacokinetics of azithromycin in serum and white blood cells of healthy subjects receiving a single-dose extended-release regimen versus a 3-day immediate-release regimen

The pharmacokinetic profiles of azithromycin given as a single-dose regimen (2.0-g extended-release microspheres) were characterized in serum and white blood cells (WBC) and compared with those of a 3-day regimen (a 500-mg immediate-release tablet once daily; total dose, 1.5 g) in an open-label, randomized, parallel-group study of 24 healthy adult subjects. Serial blood samples were collected up to 5 days after the start of dosing for both regimens. Safety assessments were conducted throughout the study. A single 2.0-g dose of azithromycin microspheres achieved significantly higher exposures in serum and WBC during the first 24 h after the start of dosing than a 3-day regimen: an approximately threefold higher area under the curve from time zero to 24 h postdose (AUC(0-24)) and an approximately twofold higher mean peak concentration on day 1. The single-dose regimen provided total azithromycin exposures in serum and WBC similar to those of the 3-day regimen, as evidenced by the similar AUC(0-120) and trough azithromycin concentrations in serum and WBC (mononuclear leukocytes [MNL] and polymorphonuclear leukocytes [PMNL]). For both regimens, the average total azithromycin exposures in MNL and PMNL were approximately 300- and 600-fold higher than those in serum. Azithromycin concentrations in MNL and PMNL remained above 10 microg/ml for at least 5 days after the start of dosing for both regimens. This "front-loading" of the dose on day 1 is safely achieved by the extended-release microsphere formulation, which maximizes the drug exposure at the time when the bacterial burden is likely to be highest.

Antibiotics for treating community acquired pneumonia in people with sickle cell disease

BACKGROUND

As a consequence of their condition, people with sickle cell disease are at high risk of developing an acute infection of the pulmonary parenchyma called community-acquired pneumonia. Many different bacteria can cause this infection and antibiotic treatment is generally needed to resolve it. There is no standardized approach to antibiotic therapy and treatment is likely to vary from country to country. Thus, there is a need to identify the efficacy and safety of different antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia.

OBJECTIVES

To determine the efficacy and safety of the antibiotic treatment approaches (monotherapy or combined) for people with sickle cell disease suffering from community-acquired pneumonia.

SEARCH STRATEGY

We searched The Group's Haemoglobinopathies Trials Register (December 2005), which comprises references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also searched The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 4, 2005), MEDLINE (1966 to December 5th, 2005), EMBASE (1974 to December 7th, 2005), and LILACS (1982 to December 2005). Date of most recent search: December 2005

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

We intended to summarise data by standard Cochrane Collaboration methodologies, but no eligible randomized controlled trials were identified.

MAIN RESULTS

We were unable to find any randomized controlled trials on antibiotic treatment approaches for community-acquired pneumonia in people with sickle cell disease.

AUTHORS' CONCLUSIONS

We were unable to identify randomized controlled trials on efficacy and safety of the antibiotic treatment approaches for people with sickle cell disease suffering from community-acquired pneumonia. Randomized controlled trials are needed to establish the optimum antibiotic treatment for this condition.

The atypical pneumonias: clinical diagnosis and importance

The most common atypical pneumonias are caused by three zoonotic pathogens, Chlamydia psittaci (psittacosis), Francisella tularensis (tularemia), and Coxiella burnetii (Q fever), and three nonzoonotic pathogens, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella. These atypical agents, unlike the typical pathogens, often cause extrapulmonary manifestations. Atypical CAPs are systemic infectious diseases with a pulmonary component and may be differentiated clinically from typical CAPs by the pattern of extrapulmonary organ involvement which is characteristic for each atypical CAP. Zoonotic pneumonias may be eliminated from diagnostic consideration with a negative contact history. The commonest clinical problem is to differentiate legionnaire's disease from typical CAP as well as from C. pneumoniae or M. pneumonia infection. Legionella is the most important atypical pathogen in terms of severity. It may be clinically differentiated from typical CAP and other atypical pathogens by the use of a weighted point system of syndromic diagnosis based on the characteristic pattern of extrapulmonary features. Because legionnaire's disease often presents as severe CAP, a presumptive diagnosis of Legionella should prompt specific testing and empirical anti-Legionella therapy such as the Winthrop-University Hospital Infectious Disease Division's weighted point score system. Most atypical pathogens are difficult or dangerous to isolate and a definitive laboratory diagnosis is usually based on indirect, i.e., direct flourescent antibody (DFA), indirect flourescent antibody (IFA). Atypical CAP is virtually always monomicrobial; increased IFA IgG tests indicate past exposure and not concurrent infection. Anti-Legionella antibiotics include macrolides, doxycycline, rifampin, quinolones, and telithromycin. The drugs with the highest level of anti-Legionella activity are quinolones and telithromycin. Therapy is usually continued for 2 weeks if potent anti-Legionella drugs are used. In adults, M. pneumoniae and C. pneumoniae may exacerbate or cause asthma. The importance of the atypical pneumonias is not related to their frequency (approximately 15% of CAPs), but to difficulties in their diagnosis, and their nonresponsiveness to beta-lactam therapy. Because of the potential role of C. pneumoniae in coronary artery disease and multiple sclerosis (MS), and the role of M. pneumoniae and C. pneumoniae in causing or exacerbating asthma, atypical CAPs also have public health importance.

[Clinical trial of chemotherapy identified according to chemosensitivity assay for oral cancer patients with unresectable recurrent lesions]

Treatment of patients with unresectable recurrent oral cancer is quite difficult. In particular,there is no scientific evidence to select anti-cancer drugs for patients who were given previous radiation therapy. To select optional chemotherapy regimens, we have employed a new chemosensitivity testing method, a collagen gel droplet embedded culture sensitivity test (CD-DST) for patients with unresectable oral cancer. Six oral cancer patients with recurrence and/or metastatic disease were treated with the optional chemotherapy based on the results of CD-DST. No result was obtained due to a problem of poor growth of tumor cells in one case. In another case, we could not find a sensitive anti-cancer drug among the agents we examined. These 2 patients were treated with selected palliative pain control therapy. Optional chemotherapy based on the results of CD-DST was given to 4 patients showing sensitivity to the anti-cancer drugs examined. Tumor recession or tumor dormancy was observed clinically during a definite period. Toxicity was mild and the median survival was 10.9 months. We therefore conclude that the examination with CD-DST may provide important scientific evidence to determine a suitable chemotherapy for patients with advanced oral cancer.

Prior outpatient antibacterial therapy as prognostic factor for mortality in hospitalized pneumonia patients

STUDY OBJECTIVES

To assess whether prior outpatient treatment is associated with outcome in patients hospitalized for community-acquired pneumonia (CAP).

PATIENTS AND METHODS

All patients with a first hospital admission for CAP between 1995 and 2000 were selected. Patients were divided into two groups, one of patients with use of antibacterial agents prior to hospitalization and one of patients treated as inpatient directly. The main outcome measures were duration of hospital stay and in-hospital mortality.

RESULTS

The two patient groups comprised 296 and 794 patients, respectively. The median duration of hospital stay was 10 days and was similar for both groups. In patients with respiratory diseases or heart failure, the median duration of hospital stay was 12 and 14 days, respectively. The overall in-hospital mortality was 7.2% and did not largely differ between both groups. In patients with congestive heart failure, the mortality was 9.8% for controls and 23.3% for patients hospitalized after initial outpatient treatment (adjusted OR 2.78, 95% CI 1.01-7.81).

CONCLUSIONS

Prior outpatient antibacterial therapy is not associated with outcome in hospitalized pneumonia patients. In patients with underlying chronic heart failure, prior outpatient antibiotic is associated with a significant increased mortality.

Appropriate outpatient treatment of acute bacterial exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis (AECB), which are characteristic of chronic obstructive pulmonary disease (COPD), contribute to morbidity and decreased quality of life for patients with COPD. A significant proportion of these exacerbations are due to bacterial infections. The Council for Appropriate and Rational Antibiotic Therapy (CARAT) criteria provide guidance for choosing the optimal drug at its optimal dose and duration for antimicrobial treatment of AECB due to bacterial infection. Evidence-based guidelines recommend stratifying patients according to risk factors to improve selection of targeted antimicrobial therapy. With increasing rates of resistance to some antimicrobials, resistance is also an important consideration for reducing treatment failures and decreasing the need for further pharmacologic treatment. Fluoroquinolones are recommended as first-line therapy for patients with chronic bronchitis who have risk factors; gatifloxacin, gemifloxacin, and levofloxacin are highly active against commonly encountered pathogens. Safety profiles are an important consideration because adverse events and poor tolerability can reduce patient adherence rates, which in turn can lead to poorer outcomes. Safety profiles also become an important consideration as shorter-course, higher-dose therapies become more prevalent. First-line therapy with a well-tolerated antibiotic that is active against the predominant pathogens, combined with low resistance rates and a convenient once-a-day dosing regimen, may reduce overall costs. Fluoroquinolones exhibit low resistance, good activity levels, and high respiratory penetration, and they are particularly well suited for shorter-course, higher-dose regimens in selected patients. Shorter-course, higher dose regimens, in turn, may be more effective, cost-efficient, and appropriate for controlling the rise of resistance than standard regimens.