Management of community-acquired pneumonia in the era of pneumococcal resistance: a report from the Drug-Resistant Streptococcus pneumoniae Therapeutic Working Group

Paediatric pulmonary disease-are we diagnosing it right?

Background

It has been reported that differential diagnosis of bacterial or viral pneumonia and tuberculosis (TB) in infants and young children is complex. This could be due to the difficulty in microbiological confirmation in this age group. In this study, we aimed to assess the utility of a real-time multiplex PCR for diagnosis of respiratory pathogens in children with pulmonary TB.

Methods

A total of 185 respiratory samples [bronchoalveolar lavage (15), gastric aspirates (98), induced sputum (21), and sputum (51)] from children aged 3-12 years, attending tertiary care hospitals, Chennai, India, were included in the study. The samples were processed by N acetyl L cysteine (NALC) NAOH treatment and subjected to microbiological investigations for Mycobacterium tuberculosis (MTB) diagnosis that involved smear microscopy, Xpert® MTB/RIF testing, and liquid culture. In addition, DNA extraction from the processed sputum was carried out and was subjected to a multiplex real-time PCR comprising a panel of bacterial and fungal pathogens.

Results

Out of the 185 samples tested, a total of 20 samples were positive for MTB by either one or more identification methods (smear, culture, and GeneXpert). Out of these 20 MTB-positive samples, 15 were positive for one or more bacterial or fungal pathogens, with different cycle threshold values. Among patients with negative MTB test results (n = 165), 145 (87%) tested positive for one or more than one bacterial or fungal pathogens.

Conclusion

The results suggest that tuberculosis could coexist with other respiratory pathogens causing pneumonia. However, a large-scale prospective study from different geographical settings that uses such simultaneous detection methods for diagnosis of childhood tuberculosis and pneumonia will help in assessing the utility of these tests in rapid diagnosis of respiratory infections.

Ceftriaxone versus ampicillin for the treatment of community-acquired pneumonia. A propensity matched cohort study

OBJECTIVES

Ceftriaxone is recommended as first-line antibiotic treatment (with the addition of macrolide) for hospitalised adults with community acquired pneumonia (CAP). Narrower-spectrum β-lactam as ampicillin, may be associated with comparable clinical outcomes, with less emergence of resistant pathogens or Clostridioides difficile infection (CDI). We aimed to examine whether ampicillin and ceftriaxone (with the addition of macrolides for both arms) are comparable for the treatment of hospitalized adults due to CAP.

METHODS

This was a single center, observational cohort study. We included adult patients who were hospitalized in internal medicine wards due to CAP and were treated with either ceftriaxone or ampicillin with the addition of macrolide. A propensity-score model was used. The primary outcome was 30-day all-cause mortality. A multivariable logistic regression analysis and Kaplan-Meier survival analysis was performed. We performed subgroup analyses for the main outcome based on CURB-65 score and age.

RESULTS

A total of 1586 patients fulfilled the inclusion criteria. There was no difference in 30-day mortality rate in the total cohort (28/233 vs. 208/1353 in ampicillin and ceftriaxone arm, respectively; p = 0.184). In the propensity matched cohort (197 in ampicillin and 394 in ceftriaxone arm), there was no significant difference in 30-day all-cause mortality between treatment groups in multivariable analysis of the main model (OR 0.67, 95% CI, 0.37-1.2; p = 0.189) and Kaplan-Meier survival analysis (p = 0.108). Thirty-day mortality rate was (19/197 vs. 57/394, in ampicillin and ceftriaxone arms, respectively; p = 0.108) Patients who were treated with ampicillin experienced significantly lower rates of CDI (0/197, 0% vs. 8/394, 2%; p = 0.044).

DISCUSSION

Ampicillin was associated with comparable clinical outcomes in comparison to ceftriaxone for patients who were hospitalized due to CAP. Ampicillin was associated with significantly lower rate of CDI. Results need to be confirmed by more robust study designs.

Comparison between Ceftriaxone and Sulbactam-Ampicillin as Initial Treatment of Community-Acquired Pneumonia: A Systematic Review and Meta-Analysis

Current guidelines recommend the use of ceftriaxone and sulbactam-ampicillin for the initial treatment of community-acquired pneumonia (CAP). However, there are no clear data on these guidelines. Therefore, this systematic review and meta-analysis aims to evaluate the effectiveness of ceftriaxone and sulbactam-ampicillin in the initial treatment of CAP. The Embase, Scopus, PubMed, Ichushi, and Cumulative Index to Nursing and Allied Health Literature databases were systematically searched from inception to July 2022. The studies included patients who received ceftriaxone or sulbactam-ampicillin as the initial antibiotic therapy for CAP. The mortality and clinical cure rates were evaluated. Of the 2152 citations identified for screening, four studies were included. Results of the pooled analysis indicated no significant differences in the mortality and clinical cure rates between patients treated with ceftriaxone and those treated with sulbactam-ampicillin (mortality, odds ratio [OR]: 1.85, 95% confidence interval [CI]: 0.57–5.96; clinical cure rate, OR: 1.08, 95% CI: 0.18–6.44). This study supports the guidelines for CAP treatment, though further studies are needed to obtain a deeper understanding.

Retrospective Comparison of the Effectiveness and Safety of Ceftriaxone 1 g Twice Daily versus 2 g Once Daily for Treatment of Aspiration Pneumonia

Although a 2 g once daily administration of ceftriaxone remains the standard dosing regimen for the treatment of aspiration pneumonia, there are no studies to investigate the optimal dosing method. Hence, we retrospectively evaluated the effectiveness and safety of 1 g twice daily versus 2 g once daily administration of ceftriaxone in adult patients with aspiration pneumonia. Patients who received ceftriaxone for the treatment of aspiration pneumonia between 2015 and 2021 were included in this study. Clinical responses, inflammatory markers, and incidence of adverse events after completion of ceftriaxone therapy were investigated. In total, 33 patients received 1 g twice daily (group 1) and 28 received 2 g once daily (group 2) ceftriaxone for the treatment of mild-to-moderate aspiration pneumonia. Compared with that of group 1, group 2 demonstrated significantly improved clinical responses (group 1 vs. group 2, 84.8% vs. 100%, p = 0.0316). Although the safety profile was not significantly different between the two groups, the incidence of choleliths during ceftriaxone therapy in group 1 was higher than that in group 2 (31.3% vs. 9.1%, p = 0.174). Therefore, a 2 g once daily administration of ceftriaxone appeared to be a simple regimen adequate for the treatment of inpatients with mild-to-moderate aspiration pneumonia, which might not be heavily involved by anaerobes.

A Broad Learning System to Predict the 28-Day Mortality of Patients Hospitalized with Community-Acquired Pneumonia: A Case-Control Study

This study was to conduct a model based on the broad learning system (BLS) for predicting the 28-day mortality of patients hospitalized with community-acquired pneumonia (CAP). A total of 1,210 eligible CAP cases from Chifeng Municipal Hospital were finally included in this retrospective case-control study. Random forest (RF) and an eXtreme Gradient Boosting (XGB) models were used to develop the prediction models. The data features extracted from BLS are utilized in RF and XGB models to predict the 28-day mortality of CAP patients, which established two integrated models BLS-RF and BLS-XGB. Our results showed the integrated model BLS-XGB as an efficient broad learning system (BLS) for predicting the death risk of patients, which not only performed better than the two basic models but also performed better than the integrated model BLS-RF and two well-known deep learning systems-deep neural network (DNN) and convolutional neural network (CNN). In conclusion, BLS-XGB may be recommended as an efficient model for predicting the 28-day mortality of CAP patients after hospital admission.

Treatment of severe pneumonia by hinokitiol in a murine antimicrobial-resistant pneumococcal pneumonia model

Streptococcus pneumoniae is often isolated from patients with community-acquired pneumonia. Antibiotics are the primary line of treatment for pneumococcal pneumonia; however, rising antimicrobial resistance is becoming more prevalent. Hinokitiol, which is isolated from trees in the cypress family, has been demonstrated to exert antibacterial activity against S. pneumoniae in vitro regardless of antimicrobial resistance. In this study, the efficacy of hinokitiol was investigated in a mouse pneumonia model. Male 8-week-old BALB/c mice were intratracheally infected with S. pneumoniae strains D39 (antimicrobial susceptible) and NU4471 (macrolide resistant). After 1 h, hinokitiol was injected via the tracheal route. Hinokitiol significantly decreased the number of S. pneumoniae in the bronchoalveolar lavage fluid (BALF) and the concentration of pneumococcal DNA in the serum, regardless of whether bacteria were resistant or susceptible to macrolides. In addition, hinokitiol decreased the infiltration of neutrophils in the lungs, as well as the concentration of inflammatory cytokines in the BALF and serum. Repeated hinokitiol injection at 18 h intervals showed downward trend in the number of S. pneumoniae in the BALF and the concentration of S. pneumoniae DNA in the serum with the number of hinokitiol administrations. These findings suggest that hinokitiol reduced bacterial load and suppressed excessive host immune response in the pneumonia mouse model. Accordingly, hinokitiol warrants further exploration as a potential candidate for the treatment of pneumococcal pneumonia.

Community-Acquired Pneumonia

Community-acquired pneumonia is an infection of the small airways and pulmonary parenchyma that develops in the outpatient setting. Despite the development of new antibiotics and vaccines, pneumonia is still a disease that occurs frequently in children under 5 years of age and is one of the main causes of mortality, especially in developing countries. The biggest challenge in treating pneumonia is to determine the agent, which depends on age, disease severity, immunological condition, geographic location, epidemiological situation, and immunizations. The classic clinical picture presents with fever, coughing, and difficulty in breathing. The physical examination shows tachypnea, reduced breath sounds, and fine crackles. Wheezing may be present in infants with viral pneumonia. The chest X-ray is considered an important tool to confirm the disease diagnosis and may guide specific treatment. Acute-phase reactants have a low sensitivity and specificity to distinguish between virus and bacteria. Microbiological identification does not have a clinical impact for most children with community-acquired pneumonia. Bronchoalveolar lavage may be considered for immunocompromised patients. Antibiotic treatment is empirical based on the best possible etiology, depending on the patient’s age and epidemiological timing. Amoxicillin is the treatment of choice for Streptococcus pneumoniae , and azithromycin is preferred for Mycoplasma pneumoniae.

Ceftriaxone versus ampicillin/sulbactam for the treatment of aspiration-associated pneumonia in adults

Aim: To compare hospital mortality in patients with aspiration-associated pneumonia treated with ceftriaxone (CTRX) and in those treated with ampicillin/sulbactam (ABPC/SBT). Methods: From a Japanese multicentre observational study cohort of patients with pneumonia, those diagnosed with pneumonia and having at least one aspiration-related risk factor were selected. Propensity score-matching analysis was used to balance baseline characteristics of the participants and compare hospital mortality of patients treated with CTRX and those treated with ABPC/SBT. Results: Hospital mortality did not significantly differ between patients treated with CTRX and those treated with ABPC/SBT (6.6 vs 10.7%, risk difference -4.0, 95% CI [-9.4, 1.3]; p = 0.143). Conclusion: Further studies are needed to compare CTRX and ABPC/SBT treatments in patients with aspiration-associated pneumonia.

Mechanism of Macrolide-Induced Inhibition of Pneumolysin Release Involves Impairment of Autolysin Release in Macrolide-Resistant Streptococcus pneumoniae

Streptococcus pneumoniae is a leading cause of community-acquired pneumonia. Over the past 2 decades, macrolide resistance among S. pneumoniae organisms has been increasing steadily and has escalated at an alarming rate worldwide. However, the use of macrolides in the treatment of community-acquired pneumonia has been reported to be effective regardless of the antibiotic susceptibility of the causative pneumococci. Although previous studies suggested that sub-MICs of macrolides inhibit the production of the pneumococcal pore-forming toxin pneumolysin by macrolide-resistant S. pneumoniae (MRSP), the underlying mechanisms of the inhibitory effect have not been fully elucidated. Here, we show that the release of pneumococcal autolysin, which promotes cell lysis and the release of pneumolysin, was inhibited by treatment with azithromycin and erythromycin, whereas replenishing with recombinant autolysin restored the release of pneumolysin from MRSP. Additionally, macrolides significantly downregulated ply transcription followed by a slight decrease of the intracellular pneumolysin level. These findings suggest the mechanisms involved in the inhibition of pneumolysin in MRSP, which may provide an additional explanation for the benefits of macrolides on the outcome of treatment for pneumococcal diseases.

Antimicrobial Resistant Streptococcus pneumoniae: Prevalence, Mechanisms, and Clinical Implications

BACKGROUND

Streptococcus pneumoniae is a major cause of pneumonia, meningitis, sepsis, bacteremia, and otitis media. S. pneumoniae has developed increased resistance to multiple classes of antibiotics.

STUDY DESIGN

Systematic literature review of prevalence, mechanisms, and clinical implications in S. pneumoniae resistance.

AREAS OF UNCERTAINTY

Since S. pneumoniae resistance to penicillin was first reported with subsequent development of resistance to other classes of drugs, selection of appropriate antibiotic treatment is challenging.

DATA SOURCES

We searched PubMed (English language) for citations to antibiotic resistance in S. pneumoniae published before March 1, 2016.

RESULTS

We present a review of S. pneumoniae resistance to beta-lactams, macrolides, lincosamides, fluoroquinolones, tetracyclines, and trimethoprim-sulfamethoxazole (TMP-SMX). There has been a steady decline in susceptibility of S. pneumoniae to commonly used beta-lactams. Phenotypic expression of penicillin resistance occurs as a result of a genetic structural modification in penicillin-binding proteins. Between 20% and 40% of S. pneumoniae isolates are resistant to macrolides. Macrolide resistance mechanisms include ribosomal target site alteration, alteration in antibiotic transport, and modification of the antibiotic. Approximately 22% of S. pneumoniae isolates are resistant to clindamycin. Similar to macrolide resistance, clindamycin involves a target site alteration. The prevalence of fluoroquinolone resistance is low, although increasing. S. pneumoniae resistance to fluoroquinolones occurs by accumulated mutations within the bacterial genome, increased efflux, or acquisition of plasmid-encoded genes. S. pneumoniae resistance has also increased for the tetracyclines. The primary mechanism is mediated by 2 genes that confer ribosomal protection. The prevalence of TMP-SMX resistance is around 35%. As with fluoroquinolones, resistance to TMP-SMX is secondary to mutations in the bacterial genome.

CONCLUSIONS

Effective treatment of resistant S. pneumoniae is a growing concern. New classes of drugs, newer formulations of older drugs, combination antibiotic therapy, nonantibiotic modalities, better oversight of antibiotic usage, and enhanced preventive measures hold promise.

Near-infrared photodynamic inactivation of S. pneumoniae and its interaction with RAW 264.7 macrophages

Pneumonia is the main cause of children mortality worldwide, and its major treatment obstacle stems from the microorganisms increasing development of resistance to several antibiotics. Photodynamic therapy has been presenting, for the last decades, promising results for some subtypes of cancer and infections. In this work we aimed to develop a safe and efficient in vitro protocol for photodynamic inactivation of Streptococcus pneumoniae, one of the most commonly found bacteria in pneumonia cases, using two near-infrared light sources and indocyanine green, a FDA approved dye. Photodynamic inactivation experiments with bacteria alone allowed to determine the best parameters for microbial inactivation. Cytotoxicity assays with RAW 264.7 macrophages evaluated the safety of the PDI. To determine if the photodynamic inactivation had a positive or negative effect on the natural killing action of macrophages, we selected and tested fewer indocyanine green concentrations and 10 J/cm² on macrophage-S. pneumoniae co-cultures. We concluded that ICG has potential as a photosensitizer for near-infrared photodynamic inactivation of S. pneumoniae, producing minimum negative impact on RAW 264.7 macrophages and having a positive interaction with the immune cell's microbicidal action.

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.

Pharmacist Impact on Pneumococcal Vaccination Rates through Incorporation of Immunization Assessment into Critical Pathways in an Acute Care Setting

Despite the availability of effective prevention and treatment measures, pneumococcal infection continues to be a significant source of morbidity and mortality. This study evaluated the impact of incorporating the assessment of pneumococcal vaccination status into selected critical pathways of at-risk patients. In a prospective, nonblinded, parallel-group trial, adult inpatients on four critical pathways were randomized into intervention or control groups. Nursing personnel screened all patients for previous pneumococcal vaccination. A pharmacist would then screen all patients for pneumococcal disease risk factors. If vaccination was indicated in the intervention group, the pharmacist educated the patient and/or caregiver, obtained patient consent, and asked the patient's physician for permission to immunize. No further action was undertaken with the control patients. A total of 231 patients were enrolled in the study (107 intervention, 124 control). Initial immunization rates were 46.8% in the control group and 56.1 % in the intervention group. Forty-six patients in the control group and 39 patients in the intervention group were eligible (unvaccinated with indication) for vaccination. Thirty-two (82.1%) of the patients in the intervention group were counseled and 19 (59.4%) were vaccinated. The overall vaccination rates were 73.8% in the intervention group and 56.1% in the control group (P < 0.001). Results indicate that incorporating assessment of pneumococcal immunization status into critical pathways is an effective way to improve immunization rates.

[Should doses of antibiotics be adjusted?]

While we are confronted with the major increase in antibiotic resistance, the preservation of existing antibiotics has become an absolute necessity both to achieve therapeutic success and to limit the risks of the emergence of resistance. The optimization of antibiotic use and dosages must have a threefold objective: guarantee antibacterial efficacy, limit toxicities and limit emergence of resistant strains. However, with the increase in the number of multipathological patients, particularly those with renal or hepatic impairment, the increase in the number of patients with extreme weights and the use of antibiotics with narrower therapeutic margins, the adaptation of antibiotic dosages is becoming increasingly important. By reminding some principles of pharmacokinetics and pharmacodynamics of antibiotics (PK/PD), the necessary objectives for clinical effectiveness of most antibiotic classes are reviewed and several examples of situations where dosage adjustments are necessary will be given. In particular, adjustment of antibiotic dosages in obese patients will be discussed. Adaptation is not limited to the adaptation of the total daily dose. The PK/PD parameters also tell us that the mode of administration (intermittent versus continuous, number of injections per day, etc.) is also an essential point to consider. By taking examples concerning some molecules, infections and difficult clinical situations, we review situations in which dosage adjustments appear necessary.

Antibiotic susceptibility in Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes in Pakistan: a review of results from the Survey of Antibiotic Resistance (SOAR) 2002-15

OBJECTIVES

To investigate changes in the antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes from the Survey of Antibiotic Resistance (SOAR) in community-acquired respiratory tract infections (CA-RTIs) between 2002 and 2015 in Pakistan.

METHODS

This is a review based on previously published studies from 2002-03, 2004-06 and 2007-09 and also new data from 2014-15. Susceptibility was determined by Etest(®) or disc diffusion according to CLSI and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

A total of 706 isolates from CA-RTIs comprising 381 S. pneumoniae, 230 H. influenzae and 95 S. pyogenes were collected between 2002 and 2015 and tested against a range of antibiotics. Antibiotic resistance in S. pneumoniae rose steeply from 2002 to 2009, with isolates non-susceptible to penicillin and macrolides increasing from 10% to 34.1% and from 13%-14% to 29.7%, respectively. Susceptibility to amoxicillin/clavulanic acid (and by inference amoxicillin) remained between 99.4% and 100% from 2002 to 2015. Over the years, the prevalence of susceptibility to cefuroxime was 98%-100% among S. pneumoniae. Resistance in S. pneumoniae to some older antibiotics between 2007 and 2009 was high (86.8% for trimethoprim/sulfamethoxazole and 57.2% for tetracycline). Between 2002 and 2015, ampicillin resistance (β-lactamase-positive strains) among H. influenzae has remained low (between 2.6% and 3.2%) and almost unchanged over the years (H. influenzae was not tested during 2004-06). For S. pyogenes isolates, macrolide resistance reached 22%; however, susceptibility to penicillin, amoxicillin/clavulanic acid and cefuroxime remained stable at 100%.

CONCLUSIONS

In S. pneumoniae from Pakistan, there has been a clear reduction in susceptibility to key antibiotics since 2002, but not to amoxicillin/clavulanic acid (amoxicillin) or cefuroxime. However, susceptibility in H. influenzae has remained stable. Local antibiotic susceptibility/resistance data are essential to support informed prescribing for CA-RTIs and other infections.

The economic burden of methicillin-resistant Staphylococcus aureus in community-onset pneumonia inpatients

BACKGROUND

The quantitative effect of multidrug-resistant bacterial infections on real-world health care resources is not clear. This study aimed to estimate the burden of methicillin-resistant Staphylococcus aureus (MRSA) infections in pneumonia inpatients in Japan.

METHODS

Using a nationwide administrative claims database, we analyzed pneumonia patients who had been hospitalized in 1,063 acute care hospitals. Patients who received anti-MRSA drugs were categorized into an anti-MRSA drug group, and the remaining patients comprised the control group. We estimated the burden of length of stay, in-hospital mortality, total antibiotic agent costs, and total hospitalization costs. Risk adjustments were conducted using propensity score matching.

RESULTS

The study sample comprised 634 patients administered anti-MRSA drugs and 87,427 control patients. In propensity score-matching analysis (1 to 1), the median length of stay, antibiotic costs, and hospitalization costs of the anti-MRSA drug group were significantly higher than those of the control group (21 days vs 14 days [P < .001], $756 vs $172 [P < .001] and $8,741 vs $5,063 [P < .001], respectively); the attributable excess of these indicators were 9.0 ± 1.6 days, $1,044 ± $101, and $5,548 ± $580, respectively.

CONCLUSIONS

These findings may serve as a reference to support further research on multidrug-resistant bacterial infections and eventually inform policy formulation.

Efficacy of Yeast' Vacuoles as Antimicrobial Agents to Escherichia coli Bacteremia in Rat

Yeast vacuoles, lysosomes, are cell organelles that have antimicrobial activity against several bacteria in vitro. Lysosomes have a potential application to the treatment of pathogens such as antibiotics in vivo. Therefore, the in vivo efficacy of lysosomes was examined in a rat infection model against pathogenic Escherichia coli with varying susceptibilities to standard antimicrobial agents. Before in vivo testing, the concentration-dependent safety of lysosomes was confirmed by blood test and histopathology of normal rats. The therapeutic efficacy of lysosomes was examined in terms of the survival of E. coli in infected rat blood. The complete blood count and histopathology results were affected by the lysosomes concentration. In addition, the E. coli growth was inhibited by the initial injection of lysosomes. These results support the use of lysosomes as a bacterial inhibitor of an infected rat model.

Short-Course Antimicrobial Therapy for the Treatment of Pneumonia

Duration of antimicrobial therapy for the treatment of pneumonia has been inconsistent and is typically at the discretion of the prescriber. Themost common durations of therapy are 7, 10, or 14 days, but courses of 14 days or longer have also been used. Newer data support the use of clinical data to identify resolution of infection, such as defervescence, normalizing white blood cell count, and absence of infiltrate on chest radiograph. Discontinuation of antimicrobials 48 to 72 hours after such clinical resolution may allow for shorter courses of therapy with equivalent efficacy as the more arbitrary end points of 7 to 14 days. The intent of this article is to review the rationale, potential benefit, and relevant studies pertaining to the use of short-course antimicrobial regimens for the treatment of community-acquired and ventilatorassociated pneumonia.

Community Acquired Pneumonia in Internal Medicine: A One-Year Retrospective Study Based on Pneumonia Severity Index

Community acquired pneumonia (CAP) represents the sixth cause of death and the first cause of death for an infectious disease in the USA. The aim of the present study is to evaluate how CAP is managed in a hospital setting, with particular attention to the wards of internal medicine, compared to the recommendations based and validated PSI (Pneumonia Severity Index). 42 subjects were included in the study, 25 males and 17 females. According to the PSI, nine (21%) patients were classified in class I, two (5%) in class II, ten (24%) in class III, fifteen (36%) in class IV and six (14%) in class V. Three patients died during the stay in the hospital (2 males and 1 female), all in the highest PSI class (V). According to the criteria used to evaluate the adequacy of the admission to the hospital, twentyeight patients were classified in the HRG, with an appropriate admission, whilst fourteen (33%) were in the LRG, with an inappropriate admission to the hospital. The data of the study confirm the validity of a PSI based strategy for the management of CAP since admittance to the hospital. This approach is not yet widely implemented in Italy, and a better dialogue between hospital and health system representatives would be convenient, to reduce costs and ensure the safety of patients affected by CAP.

Comparative Outcome Analysis of Penicillin-Based Versus Fluoroquinolone-Based Antibiotic Therapy for Community-Acquired Pneumonia: A Nationwide Population-Based Cohort Study

Community-acquired pneumonia (CAP) is a common but potentially life-threatening condition, but limited information exists on the effectiveness of fluoroquinolones compared to β-lactams in outpatient settings. We aimed to compare the effectiveness and outcomes of penicillins versus respiratory fluoroquinolones for CAP at outpatient clinics.This was a claim-based retrospective cohort study. Patients aged 20 years or older with at least 1 new pneumonia treatment episode were included, and the index penicillin or respiratory fluoroquinolone therapies for a pneumonia episode were at least 5 days in duration. The 2 groups were matched by propensity scores. Cox proportional hazard models were used to compare the rates of hospitalizations/emergence service visits and 30-day mortality. A logistic model was used to compare the likelihood of treatment failure between the 2 groups.After propensity score matching, 2622 matched pairs were included in the final model. The likelihood of treatment failure of fluoroquinolone-based therapy was lower than that of penicillin-based therapy (adjusted odds ratio [AOR], 0.88; 95% confidence interval [95%CI], 0.77-0.99), but no differences were found in hospitalization/emergence service (ES) visits (adjusted hazard ratio [HR], 1.27; 95% CI, 0.92-1.74) and 30-day mortality (adjusted HR, 0.69; 95% CI, 0.30-1.62) between the 2 groups.The likelihood of treatment failure of fluoroquinolone-based therapy was lower than that of penicillin-based therapy for CAP on an outpatient clinic basis. However, this effect may be marginal. Further investigation into the comparative effectiveness of these 2 treatment options is warranted.

Improvement of antibiotic therapy and ICU survival in severe non-pneumococcal community-acquired pneumonia: a matched case-control study

INTRODUCTION

We aimed to compare intensive care unit mortality due to non-pneumococcal severe community-acquired pneumonia between the periods 2000-2002 and 2008-2014, and the impact of the improvement in antibiotic strategies on outcomes.

METHODS

This was a matched case-control study enrolling 144 patients with non-pneumococcal severe pneumonia: 72 patients from the 2000-2002 database (CAPUCI I group) were paired with 72 from the 2008-2014 period (CAPUCI II group), matched by the following variables: microorganism, shock at admission, invasive mechanical ventilation, immunocompromise, chronic obstructive pulmonary disease, and age over 65 years.

RESULTS

The most frequent microorganism was methicillin-susceptible Staphylococcus aureus (22.1%) followed by Legionella pneumophila and Haemophilus influenzae (each 20.7%); prevalence of shock was 59.7%, while 73.6% of patients needed invasive mechanical ventilation. Intensive care unit mortality was significantly lower in the CAPUCI II group (34.7% versus 16.7%; odds ratio (OR) 0.78, 95% confidence interval (CI) 0.64-0.95; p = 0.02). Appropriate therapy according to microorganism was 91.5% in CAPUCI I and 92.7% in CAPUCI II, while combined therapy and early antibiotic treatment were significantly higher in CAPUCI II (76.4 versus 90.3% and 37.5 versus 63.9%; p < 0.05). In the multivariate analysis, combined antibiotic therapy (OR 0.23, 95% CI 0.07-0.74) and early antibiotic treatment (OR 0.07, 95% CI 0.02-0.22) were independently associated with decreased intensive care unit mortality.

CONCLUSIONS

In non-pneumococcal severe community-acquired pneumonia , early antibiotic administration and use of combined antibiotic therapy were both associated with increased intensive care unit survival during the study period.

What Is New in Antibiotic Therapy in Community-Acquired Pneumonia? An Evidence-Based Approach Focusing on Combined Therapy

Despite all published literature, controversies remain about the optimal antibiotic treatment in community-acquired pneumonia. The most debated issue is whether it is necessary to empirically start one or two antibiotics, i.e. whether or not to cover atypical agents. A review of the literature published from 2005 to present was completed, searching for new insights in antibiotic treatment in community-acquired pneumonia (CAP) focusing on monotherapy versus combined therapy. Forty-one articles were identified enrolling outpatients, and patients admitted to the ward and to the intensive care unit: 11 were meta-analyses, 8 clinical trials and 22 observational-prospective and retrospective-studies. Although controversies remain in the treatment of CAP, the use of combination therapy seems to be associated with a lower mortality in case of severe CAP that requires intensive care unit (ICU) admission, especially when a beta-lactam-macrolide association is delivered. Moreover, combination therapy is associated with better outcomes-although not always with a lower mortality-in cases of non-ICU patients with risk factors for a poor outcome, bacteraemic pneumococcal pneumonia and high suspicion of infection by atypical agents. In this setting, it appears that the best choice of treatment may be a beta-lactam-macrolide regimen.

A Comparison of Cefditoren Pivoxil 8-12 mg/kg/day and Cefditoren Pivoxil 16-20 mg/kg/day in Treatment of Children With Acute Presumed Bacterial Rhinosinusitis: A Prospective, Randomized, Investigator-Blinded, Parallel-Group Study

OBJECTIVES

Cefditoren pivoxil (CDT) has been used in the treatment of rhinosinusitis. However, little is known about the efficacy of this drug at low and high doses. This study was to compare the efficacy and safety of low dose (8-12 mg/kg/day) and high dose (16-20 mg/kg/day) CDT in the treatment of children with uncomplicated acute rhinosinusitis (ARS).

METHODS

This investigation was a randomized, investigator-blinded, and parallel study, conducted in patients (aged 1-15 years) with a clinical diagnosis of uncomplicated ARS. Two groups of patients randomly received low dose or high dose CDT for 14 days. Patients' symptoms were assessed quantitatively using a quantitative symptom score (the S5 score). The changes in sinus symptoms and adverse events were provided by patients and their parents/caregivers. The response rate and adverse effects were evaluated at days 7 and 14. The relapse rate was recorded at days 21 and 28. The recurrences of sinus symptoms at day 60 were also assessed.

RESULTS

One hundred forty patients were recruited and randomized; 72 received low dose CDT (group I) and 68 received high dose CDT (group II). There were no significant differences in demographic data including sex, age, presenting symptoms, medical history, and X-ray findings between two groups. The responses rate at day 14 in groups I and II were 95.5% and 95.4%, respectively (P>0.99). There were no significant differences between groups in relapse rate at day 28 and no recurrence at day 60 in either group. The most common treatment-related adverse events were diarrhea (4.2% in group I vs. 2.9% in group II) and vomiting (2.8% in group I vs. 10.3% in group II). There was no statistically significant difference in adverse events between groups.

CONCLUSION

Both low and high doses regimens of CDT appeared a similar clinical outcome for treatment in uncomplicated ARS in pediatric patients.

Nosokomiale Pneumonie – Antibiotikatherapie und hygienische Interventionsstrategien

Die Pneumonie ist auch in unserer Zeit eine schwere Infektionskrankheit. Sie ist eine der häufigsten infektiösen Todesursachen der westlichen Industrieländer und steht an 3. Stelle unter den Infektionskrankheiten. Jede 4. ärztlich diagnostizierte Pneumonie ist nosokomial erworben. Nosokomiale Pneumonien führen neben einer verlängerten Morbidität und erhöhten Letalität zu einer Verlängerung der Krankenhausverweildauer und zu erheblichen Kosten.

History of antibiotics: from fluoroquinolones to daptomycin (Part 2)

In the Modern Era, physicians attested to the reciprocal influence among a technologically advanced society, rapid scientific progresses in medicine, and the need for new antimicrobials. The results of these changes were not only seen in the prolongation of life expectancy but also by the emergence of new pathogens. We first observed the advent of Gram-negative bacteria as a major source of nosocomial infections. The treatment of these microorganisms was complicated by the appearance and spread of drug resistance. We first focused on the development of two major classes of antimicrobials still currently used for the treatment of Gram-negative bacteria, such as fluoroquinolones and carbapenemes. Subsequently, we directed our attention to the growth of the incidence of infections due to Methicillin-Resistant Staphylococcus aureus (MRSA). Although the first MRSA was already isolated in 1961, the treatment of this new pathogen has been based on the efficacy of vancomycin for more than four decades. Only in the last 15 yr, we assisted in the development of new antimicrobial agents such as linezolid and daptomycin.

Etiology and Anti-microbial Sensitivity of Organisms Causing Community Acquired Pneumonia: A Single Hospital Study

Objective:

The objective of this study was to identify the common etiological pathogens causing community acquired pneumonia (CAP) in our hospital and sensitivity patterns to the common antibiotics used.

Materials and Methods:

This study was undertaken in a 750 bedded multi-specialty referral hospital in Kerala catering to both urban and semi-urban populations. It is a prospective study of patients who attended the medical out-patient department and those admitted with a clinical diagnosis of CAP, during the year 2009. Data were collected based on detailed patient interview, clinical examination and laboratory investigations. The latter included sputum culture and sensitivity pattern. These were tabulated and percentage incidence of etiological pathogens calculated. The antimicrobial sensitivity pattern was also classified by percentage and expressed as bar diagram.

Results:

The study showed Streptococcus pneumoniae to be the most common etiological agent for CAP, in our hospital setting. The other organisms isolated in order of frequency were Klebsiella pneumoniae, Pseudomonas aeruginosa, Alpha hemolytic streptococci, Escherichia coli, Beta hemolytic streptococci and atypical coli. S. pneumoniae was most sensitive to linezolid, followed by amoxicillin-clavulanate (augmentin), cloxacillin and ceftriaxone. Overall, the common pathogens causing CAP showed highest sensitivity to amikacin, followed by ofloxacin, gentamycin, amoxicillin-clavulanate (augmentin), ceftriaxone and linezolid. The least sensitivity rates were shown to amoxicillin and cefoperazone.

Conclusion:

In a hospital setting, empirical management for cases of CAP is not advisable. The present study has shown S. pneumoniae as the most likely pathogen and either linezolid or amikacin as the most likely effective antimicrobial in cases of CAP, in our setting.

Clarithromycin (Biaxin®) extended-release tablet: a therapeutic review

Clarithromycin (Biaxin) extended-release tablets, an advanced generation macrolide, were recently introduced into the USA for the treatment of acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis. The reformulation is intended to improve both patient compliance and tolerability. The extended-release tablets allow convenient once-daily dosing (1000 mg). The extended-release formulation has been shown to be equivalent to the immediate-release formulation concerning area under the plasma concentration time curve. In comparative clinical trials for acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis, clarithromycin extended-release tablets were equivalent to the immediate-release formulation concerning clinical efficacy and bacterial eradication, with improved gastrointestinal tolerability. Similar efficacy and gastrointestinal tolerability results were demonstrated in a recent comparative study of clarithromycin extended-release formulation and amoxicillin-clavulanate in patients with acute exacerbations of chronic bronchitis. Clarithromycin extended-release 1000 mg daily has also been shown to be equivalent to levofloxacin 500 mg daily for the treatment of community-acquired pneumonia in a recent study. The macrolide class of antimicrobials, including clarithromycin extended-release, continues to be a safe and efficacious choice for the out-patient management of community-acquired bacterial respiratory tract infections.

Extended release amoxicillin/clavulanate: optimizing a product for respiratory infections based on pharmacodynamic principles

Acute bacterial respiratory tract infections cause a great deal of human morbidity and mortality. Treatment guidelines for these infections include macrolides, doxycycline, beta-lactams and beta-lactam/beta-lactamase inhibitor combinations such as amoxicillin/clavulanic acid to provide coverage for the common respiratory pathogens, including penicillin and macrolide nonsusceptible Streptococcus pneumoniae, as well as beta-lactamase-producing Haemophilus influenzae and Moraxella catarrhalis. In response to recent guidelines recommending higher dose amoxicillin to extend coverage to a higher percentage of S. pneumoniae, a new formulation of amoxicillin/clavulanic acid was developed. This formulation includes a higher amoxicillin dose, with part of the amoxicillin dose being in an extended release formulation, without increasing the clavulanate dose, for twice-daily oral treatment of these infections. Clinical studies of community-acquired pneumonia and acute rhinosinusitis have shown that the new formulation is well tolerated and highly efficacious, with clinical outcomes equivalent to comparators.

Influence of pharmacokinetics/pharmacodynamics of antibacterials in their dosing regimen selection

The choice of antimicrobial dosing in clinical practice in the past was based upon a 'penicillin mentality', that is, on the assumption that the in vivo antimicrobial efficacy is dependent on the duration of drug levels above the minimum inhibitory concentration of target microorganisms. Really, a rational antimicrobial therapy is strongly related to a basic understanding of the influence the patient has on the antibiotic (pharmacokinetics [PKs]) and the patient's response to the specific drug effects (pharmacodynamics [PDs]). PK/PD parameters are essential in facilitating the translation of microbiological activity into clinical situations, ensuring a successful outcome. This review will analyze the typical patterns of antimicrobial activity and the corresponding PK/PD parameters, with a special focus on a PK/PD dosing approach with the most commonly utilized antimicrobial agent classes.

Levofloxacin: update and perspectives on one of the original ‘respiratory quinolones’

The fluoroquinolone class of antimicrobials has enjoyed enormous clinical and marketing success over the past 20 years. These drugs have proven to be extremely useful in a broad range of clinical indications including both common community-acquired as well as nosocomial bacterial infections. Levofloxacin (Levaquin, Tavanic), like ciprofloxacin (Cipro), has established an enviable record of safe and efficacious use, and in many ways has become the agent against which all of the newer fluoroquinolones are judged. New clinical indications in complicated skin and skin structure infections, nosocomial pneumonia and chronic bacterial prostatitis continue to expand the important role of this already versatile drug. In addition, the use of 'short-course, high-dose' therapies are being studied in indications, such as community-acquired pneumonia, in an effort to optimize the efficacy and convenience of the drug while minimizing the future development of resistance. As the use of levofloxacin continues to expand, future challenges will include the threat of increasing antimicrobial resistance and the availability of newer alternative agents, both newer fluoroquinolones as well as agents of other antibiotic classes.

Antibiotic treatment of children with community-acquired pneumonia: comparison of penicillin or ampicillin versus cefuroxime

OBJECTIVE

Adherence to current guidelines for treatment of non-complicated community-acquired pneumonia (CAP) in children, recommending penicillin or ampicillin as first-line treatment, has been poor. Our objective was to examine whether cefuroxime confers an advantage over penicillin or ampicillin for the treatment of children hospitalized with non-complicated CAP.

PATIENTS AND METHODS

All children aged 3 months to 2 years with non-complicated CAP treated with penicillin or ampicillin or cefuroxime, admitted during 2003-2008, in the Departments of Pediatrics, Hadassah University Medical Center were included. Presenting signs, symptoms, laboratory findings at presentation, clinical parameters including number of days with IV antibiotics, oxygen treatment, length of hospital stay, change of antibiotics, and clinical course 72 hr and 1 week after admission, were compared.

RESULTS

Of the 319 children admitted for non-complicated CAP, 66 were treated with IV penicillin or ampicillin, 253 with IV cefuroxime. Number of days of IV treatment, days of oxygen requirement, and days of hospitalization were similar (2.36 ± 1.6 days vs. 2.59 ± 1.6 days, 0.31 ± 1.2 days vs. 0.64 ± 1.3 days, and 2.67 ± 1.4 days vs. 2.96 ± 1.7 days, respectively). Treatment failure was not significantly different (7.6% vs. 4.7%). The number of patients who were febrile or required oxygen 72 hr after admission was similar (13.0% vs. 16.5% and 8.7% vs. 20.9%, respectively). One week after admission no difference between the two groups was seen.

CONCLUSIONS

In previously healthy children, parenteral penicillin or ampicillin for treatment of non-complicated CAP in-hospital is as effective as cefuroxime, and should remain the recommended first-line therapy.

Comparison of Clarithromycin and Amoxicillin/Clavulanic Acid for Community-Acquired Pneumonia in an Era of Drug-Resistant Streptococcus pneumoniae

OBJECTIVE

To compare the safety and efficacy of clarithromycin and amoxicillin/clavulanic acid in patients with community-acquired pneumonia due to penicillin-resistant and/or macrolide-resistant Streptococcus pneumoniae, by selecting clinical investigators who practice in study populations from geographic areas in which a high incidence of resistant strains is reported by surveillance.

DESIGN AND SETTING

Prospective, randomised, investigator-blinded, multicentre study conducted in 45 sites in primary-care and referral centre settings.

PATIENTS AND INTERVENTIONS

327 ambulatory patients diagnosed with radio-graphically confirmed community-acquired pneumonia administered clarithromycin 500mg immediate-release or amoxicillin/clavulanic acid 875mg/125mg twice daily for 7 days.

MAIN OUTCOME MEASURES AND RESULTS

Similarly high clinical cure rates were observed among evaluable patients in both treatment groups at the test-of-cure visit (28-35 days post-treatment): 92% (114/124) for clarithromycin and 91% (117/129) for amoxicillin/clavulanic acid. Of 85 S. pneumoniae strains isolated pretreatment, four (5%) were classified as resistant to macrolides (one mefA, two ermB, and one ermB + mefA) and eight (9%) had reduced susceptibility to penicillin. The overall eradication rate for pathogens isolated from bacteriologically and clinically evaluable patients was 91% for clarithromycin and 93% for amoxicillin/clavulanic acid, and 89% and 92%, respectively, for S. pneumoniae strains. The rates of resolution and/or improvement in clinical signs and symptoms and radiological improvement were similar with clarithromycin to those with amoxicillin/clavulanic acid, as was overall incidence of adverse events.

CONCLUSION

A 7-day course of clarithromycin immediate-release was similar to amoxicillin/clavulanic acid based on high rates (>90%) of clinical cure, radiological improvement and pathogen eradication among ambulatory-care patients with community-acquired pneumonia. As the resistance rate at baseline was low, no conclusion could be made about clarithromycin's efficacy for infections caused by macrolide-resistant S. pneumoniae. Both treatments were well tolerated.

Cefepime

Cefepime (Maxipime), Maxcef, Cepimax, Cepimex, Axepim, a parenteral fourth-generation cephalosporin, is active against many organisms causative in pneumonia. Cefepime has in vitro activity against Gram-positive organisms including Staphylococcus aureus and penicillin-sensitive, -intermediate and -resistant Streptococcus pneumoniae similar to that of cefotaxime and ceftriaxone. Cefepime also has good activity against Gram-negative organisms, including Pseudomonas aeruginosa, similar to that of ceftazidime. Importantly, cefepime is stable against many of the common plasmid- and chromosome-mediated beta-lactamases and is a poor inducer of AmpC beta-lactamases. As a result, it retains activity against Enterobacteriaceae that are resistant to third-generation cephalosporins, such as derepressed mutants of Enterobacter spp. Cefepime may be hydrolyzed by the extended-spectrum beta-lactamases produced by some members of the Enterobacteriaceae, but to a lesser extent than the third-generation cephalosporins. Monotherapy with cefepime 1 or 2g, usually administered intravenously twice daily, was as effective for clinical and bacteriological response as ceftazidime, ceftriaxone or cefotaxime monotherapy (1 or 2g two or three times daily) in a number of randomized, clinical trials in hospitalized adult, or less commonly, pediatric, patients with generally moderate to severe community-acquired or nosocomial pneumonia. More limited data indicated that monotherapy with cefepime 2g three times daily was also as effective in treating patients with nosocomial pneumonia as imipenem/cilostatin 0.5g four times daily, and when combined with amikacin, cefepime was as effective as ceftazidime plus amikacin. Patients with pneumonia who failed to respond to previous antibacterial therapy with penicillins or other cephalosporins responded to treatment with cefepime. Cefepime is generally well tolerated, with a tolerability profile similar to those of other parenteral cephalosporins. In clinical trials, the majority of adverse events experienced by cefepime recipients were mild to moderate and reversible. The most common adverse events with a causal relationship to cefepime reported in clinical trials included rash and diarrhea. Other, less common, adverse events included pruritus, urticaria, nausea, vomiting oral candidiasis, colitis, headache, fever, erythema and vaginitis.

CONCLUSION

Cefepime is an established and generally well tolerated parenteral drug with a broad spectrum of antibacterial activity which, when administered twice daily, provides coverage of most of the pathogens that may be causative in pneumonia. In randomized clinical trials in hospitalized patients with generally moderate to severe community-acquired or nosocomial pneumonia, cefepime monotherapy exhibited good clinical and bacteriological efficacy. Cefepime may become a preferred antibacterial agent for infections caused by Enterobacter spp. With prudent use in order to prevent the emergence of resistant organisms, cefepime will continue to be a suitable option for the empiric treatment of pneumonia.

Pharmacodynamics for predicting therapeutic outcome and countering resistance spread: The cefditoren case

The relationship between pharmacokinetics and pharmacodynamics is a key instrument to improve antimicrobial stewardship and should be aimed to identification of the drug exposure measure that is closely associated not only with the ability to kill organisms but also to suppress the emergence of resistant subpopulations. This article reviews published studies for efficacy prediction with cefditoren and those aimed to explore its potential for countering resistance spread, focusing on the three most prevalent community-acquired isolates from respiratory infections: Streptococcus pneumoniae (S. pneumoniae), Haemophilus influenzae (H. influenzae) and Streptococcus pyogenes (S. pyogenes). Studies for efficacy prediction include in vitro pharmacodynamic simulations (using physiological concentrations of human albumin) and mice models (taking advantage of the same protein binding rate in mice and humans) to determine the value of the pharmacodynamic indices predicting efficacy, and Monte Carlo simulations to explore population pharmacodynamic coverage, as weapons for establishing breakpoints. Studies exploring the potential of cefditoren (free concentrations obtained with 400 mg cefditoren bid administration) for countering spread of resistance showed its capability for countering (1) intra-strain spread of resistance linked to ftsI gene mutations in H. influenzae; (2) the spread of H. influenzae resistant strains (with ftsI gene mutations) in multi-strain H. influenzae niches or of S. pneumoniae strains with multiple resistance traits in multi-strain S. pneumoniae niches; and (3) for overcoming indirect pathogenicity linked to β-lactamase production by H. influenzae that protects S. pyogenes in multibacterial niches. This revision evidences the ecological potential for cefditoren (countering resistance spread among human-adapted commensals) and its adequate pharmacodynamic coverage of respiratory pathogens (including those resistant to previous oral compounds) producing community-acquired infections.

Update on the clinical utility and optimal use of cefditoren

This article reviews and updates published data on cefditoren. The in vitro activity of cefditoren and its potential pharmacokinetic/pharmacodynamic adequacy to cover emerging resistance phenotypes in the present decade is reviewed. Cefditoren’s in vitro activity against most prevalent bacterial respiratory pathogens in the community and its pharmacokinetic/pharmacodynamic profile suggests a significant role for cefditoren in the treatment of respiratory tract infections. Clinical trials (in acute exacerbations of chronic bronchitis, community-acquired pneumonia, pharyngotonsillitis, and sinusitis) performed during clinical development outside Japan, mainly in adults, are reviewed, together with new clinical studies in the treatment of pharyngotonsillitis, sinusitis, and otitis media in children, mainly in Japan, for efficacy and safety assessment. The results of these studies support the adequacy of cefditoren for the treatment of community-acquired respiratory tract infections with a safety profile similar to previous oral antibiotics. From the data reviewed, it is concluded that cefditoren is an adequate option for the treatment of mild-to-moderate community-acquired respiratory infections, especially in geographical areas with a reported prevalence of phenotypes exhibiting nonsusceptibility to common oral antibiotics.

Pneumonia in adults: the practical emergency department perspective

In those patients who are hospitalized with pneumonia, mortality is 15%. Close to 90% of deaths attributed to pneumonia are in patients older than 65 years. This article provides the emergency physician with an understanding of how to make the diagnosis, initiate early and appropriate antibiotic therapy, risk stratify patients with respect to the severity of illness, and recognize indications for admission. The discussion is balanced with an emphasis on cost-effective management, an understanding of the changing spectrum of pathogenesis, and a cognizance toward variable and less common presentations.

MODELING THE DIFFERENCES IN THE DEVELOPMENT OF A NEW ANTIBIOTIC CLASS VERSUS THE DEVELOPMENT OF A NEXT GENERATION ANTIBIOTIC ON THE TOTAL RESISTANCE IN A HOSPITAL SETTING

The increase in antibiotic resistance continues to pose a major public health risk leading to a more intense focus on ways to limit and even reduce this threat. One such effort is the push for twenty new classes of antibiotics by the year 2020. Most of the current antibiotics used today are derivations of antibiotics first introduced forty to fifty years ago. In this paper, we develop mathematical models to simulate the difference between implementing a next generation antibiotic versus a new class antibiotic within a hospital setting. Using these models, we simulate the short term and long term effects of using the new antibiotic to combat existing levels of antimicrobial resistance. In addition to analyzing the difference in antibiotic classes, we also analyze the effects of the method of administration of the new antibiotic. Simulations suggest a need in the long term for the development of new classes of antibiotics administered in a very structured, targeted manner.

Combination antibiotic therapy for community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common and potentially serious illness that is associated with morbidity and mortality. Although medical care has improved during the past decades, it is still potentially lethal. Streptococcus pneumoniae is the most frequent microorganism isolated. Treatment includes mandatory antibiotic therapy and organ support as needed. There are several antibiotic therapy regimens that include β-lactams or macrolides or fluoroquinolones alone or in combination. Combination antibiotic therapy achieves a better outcome compared with monotherapy and it should be given in the following subset of patients with CAP: outpatients with comorbidities and previous antibiotic therapy, nursing home patients with CAP, hospitalized patients with severe CAP, bacteremic pneumococcal CAP, presence of shock, and necessity of mechanical ventilation. Better outcome is associated with combination therapy that includes a macrolide for wide coverage of atypical pneumonia, polymicrobial pneumonia, or resistant Streptococcus pneumoniae. Macrolides have shown different properties other than antimicrobial activity, such as anti-inflammatory properties. Although this evidence comes from observational, most of them retrospective and nonblinded studies, the findings are consistent. Ideally, a prospective, multicenter, randomized trial should be performed to confirm these findings.

Bronconeumopatías agudas del niño

Las infecciones infantiles afectan con frecuencia al aparato respiratorio inferior. Las clasificaciones convencionales, basadas en el tipo de afección anatómica, radiológica y etiopatogénica, permiten definir entidades clínicas (bronquitis, bronquiolitis, neumopatía); sin embargo, la evaluación de la gravedad del proceso es lo más útil para decidir el tipo y la rapidez del tratamiento. Aunque la etiología viral es la más frecuente, la estrategia fundamental para reducir la morbilidad e incluso la mortalidad de las infecciones respiratorias bajas se basa en el tratamiento adecuado de las neumonías bacterianas. Ante la ausencia de especificidad, es indispensable, cuando esté indicado, recurrir a una antibioticoterapia inicial probabilística que incluya el neumococo. En el niño, las muestras no suelen proceder del parénquima pulmonar y, además, la recogida de las secreciones bronquiales durante los primeros años de vida no es de buena calidad. Al contrario de lo que ocurre con los virus, el examen bacteriológico de las secreciones de las vías respiratorias altas es poco útil, porque los niños suelen ser portadores de gérmenes que pueden causar neumopatías. Los datos clínicos y radiológicos sólo pueden sugerir el diagnóstico. El desarrollo de técnicas que detectan antígenos microbianos o la búsqueda de material genético por biología molecular han permitido mejorar de manera significativa la identificación del patógeno responsable y la elección del tratamiento adecuado. Algunos grupos particulares de pacientes pueden padecer una afección respiratoria por agentes infecciosos inusuales o, incluso, oportunistas. Una proporción importante de la afectación respiratoria del adulto puede atribuirse a las agresiones pulmonares sufridas durante su infancia. La aplicación de vacunas, en especial, la antigripal y la antineumocócica, es fundamental para la prevención de estas afecciones respiratorias.

Japanese Guidelines for the Management of Respiratory Infectious Diseases in Children 2007 with focus on pneumonia

Members of the Japanese Society of Pediatric Pulmonology and the Japanese Society for Pediatric Infectious Diseases developed the Guidelines for the Management of Respiratory Infectious Diseases in Children with the objective of facilitating the appropriate diagnosis and treatment of childhood respiratory infections. To date, a first edition (2004) and a revised edition (2007) have been issued. Many problems complicate the diagnosis of the pathogens responsible for bronchopulmonary infections in children. The Guidelines were the first pediatric guidelines in the world to recommend treatment with antimicrobials suited to causative pathogens as identified from cultures of sputum and other clinical specimens collected from infection sites and satisfying assessment criteria. The major causative microorganisms for pneumonia in infants and children were revealed to be Streptococcus pneumoniae, Haemophilus influenzae and Mycoplasma pneumoniae. This manuscript describes the Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan 2007, with a focus on pneumonia.

Perfil fenotípico e susceptibilidade antimicrobiana de Streptococcus equi isolados de equinos da região Sul do Brasil

As características fenotípicas [morfológicas, bioquímicas, susceptibilidade aos antimicrobianos, índice de resistência múltipla aos antimicrobianos (IRMA), concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) da benzilpenicilina] de 38 isolados de Streptococcus equi oriundos de amostras clínicas de animais com adenite equina foram alvo deste estudo. A fenotipia demonstrou três padrões de colônias, três biotipos de fermentação de carboidratos e variação de 0 a 0,4 no IRMA. Todos os isolados de S. equi demonstraram sensibilidade à penicilina, tanto pelo método de disco difusão quanto pelo método de microdiluição. A CIM e CBM média de benzilpenicilina foi de 0,0095μg/mL e 0,0267μg/mL para S. equi subesp. equi e de 0,0128μg/mL e 0,0380μg/mL para S. equi subesp. zooepidemicus. Os valores de CIM e CBM diferiram entre as subespécies (p<0,05). O diâmetro do halo de inibição de penicilina demonstrou relação com a CIM (ì=0,03638 - 0,00072x) para S. equi subesp. equi. Também foi demonstrada relação entre o diâmetro do halo de inibição de penicilina com a CBM para S. equi subesp. equi (ì=0,10931- 0,00223x). Entretanto para as amostras de S. equi subesp. zooepidemicus esta relação somente foi verificada para a CBM (ì=0,1322 - 0,00271x). A CIM de benzilpenicilina frente às amostras isoladas da região Central, Planalto e Sul do estado do Rio Grande do Sul foram estatisticamente semelhantes, mas diferiram do isolado do estado do Paraná, sugerindo o caráter atípico desta cepa. Todos os isolados de S. equi são sensíveis à penicilina e sulfazotrim, confirmando a eleição destes antimicrobianos para o tratamento das infecções por este agente na clínica veterinária. Os resultados obtidos não dispensam a utilização prudente dos antimicrobianos.

Cefditoren in upper and lower community-acquired respiratory tract infections

This article reviews and updates published data on cefditoren in the evolving scenario of resistance among the most prevalent isolates from respiratory tract infections in the community (Streptococcus pyogenes, Haemophilus influenzae, and Streptococcus pneumoniae). By relating the in vitro activity of cefditoren (in national and multinational surveillance and against isolates with emerging resistant genotypes/phenotypes) to its pharmacokinetics, the cefditoren pharmacodynamic activity predicting efficacy (in humans, animal models, and in vitro simulations) is analyzed prior to reviewing clinical studies (tonsillopharyngitis, sinusitis, acute exacerbations of chronic bronchitis, and community-acquired pneumonia) and the relationship between bacterial eradication and clinical efficacy. The high in vitro activity of cefditoren against the most prevalent respiratory isolates in the community, together with its pharmacokinetics (enabling a twice daily regimen) leading to adequate pharmacodynamic indexes covering all S. pyogenes, H. influenzae, and at least 95% S. pneumoniae isolates, makes cefditoren an antibiotic that will play a significant role in the treatment of respiratory tract infections in the community. In the clinical setting, studies carried out with cefditoren showed that treatments with the 400 mg twice daily regimen were associated with high rates of bacteriological response, even against penicillin-nonsusceptible S. pneumoniae, with good correlation between bacteriological efficacy/response and clinical outcome.

The pharmacokinetics and pharmacodynamics of the carbapanemes: focus on doripenem

Carbapenems are the most potent group of beta-lactam agents, having a broad spectrum of bactericidal activity against both Gram-negative and Gram-positive bacteria including anaerobes. Doripenem is a new carbapenem endowed with excellent bactericidal activity, a wide spectrum of antibacterial activity against difficult nosocomial pathogens, including extended-spectrum beta-lactamase producers. Its high stability in solution render it extremely flexible for dosing and infusion time. It is the only carbapenem which has been registered officially for administration as an extended infusion of more than 4 hours, which can thus enhance its potential clinical efficacy against difficult bacterial pathogens with MICs of 4-8 mg/L.