Community-acquired lower respiratory tract infections: etiology and treatment

Combining different bacteria in vaccine formulations enhances the chance for antiviral cross-reactive immunity: a detailed in silico analysis for influenza A virus

Bacteria are well known to provide heterologous immunity against viral infections through various mechanisms including the induction of innate trained immunity and adaptive cross-reactive immunity. Cross-reactive immunity from bacteria to viruses is responsible for long-term protection and yet its role has been downplayed due the difficulty of determining antigen-specific responses. Here, we carried out a systematic evaluation of the potential cross-reactive immunity from selected bacteria known to induce heterologous immunity against various viruses causing recurrent respiratory infections. The bacteria selected in this work were Bacillus Calmette Guerin and those included in the poly-bacterial preparation MV130: Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Klebisella pneumoniae, Branhamella catarrhalis and Haemophilus influenzae. The virus included influenza A and B viruses, human rhinovirus A, B and C, respiratory syncytial virus A and B and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through BLAST searches, we first identified the shared peptidome space (identity ≥ 80%, in at least 8 residues) between bacteria and viruses, and subsequently predicted T and B cell epitopes within shared peptides. Interestingly, the potential epitope spaces shared between bacteria in MV130 and viruses are non-overlapping. Hence, combining diverse bacteria can enhance cross-reactive immunity. We next analyzed in detail the cross-reactive T and B cell epitopes between MV130 and influenza A virus. We found that MV130 contains numerous cross-reactive T cell epitopes with high population protection coverage and potentially neutralizing B cell epitopes recognizing hemagglutinin and matrix protein 2. These results contribute to explain the immune enhancing properties of MV130 observed in the clinic against respiratory viral infections.

Economic Evaluation of Vaccines: Belgian Reflections on the Need for a Broader Perspective

OBJECTIVES

The standard framework of economic evaluation of health programs, which is increasingly used for policy funding decisions, is insufficiently equipped to reflect the full range of health and economic benefits conferred by vaccines and thus undervalues vaccination.

METHODS

In 2019, a group of Belgian health economic and clinical experts, supported by 2 senior international vaccination experts (1 American, 1 Belgian), convened 4 roundtable meetings to highlight which particular value elements of vaccination remain neglected in economic evaluations.

RESULTS

They concluded that the standard economic evaluation framework fails to reflect the full value of vaccination with respect to prevention of complications linked to some vaccine-preventable diseases, health gains for caregivers, herd effects, changes in exposure to and distribution of serotypes, the effect on antimicrobial resistance, productivity gains for caregivers and patients, and the distributive implications of vaccination programs.

CONCLUSIONS

Here, suggestions are made regarding how these shortcomings can be addressed in future economic evaluations of vaccines and how a more level playing field between vaccines and other health programs can be created.

Involvement of Mesenchymal Stem Cells in Oral Mucosal Bacterial Immunotherapy

Recent clinical observations indicate that bacterial vaccines induce cross-protection against infections produced by different microorganisms. MV130, a polyvalent bacterial sublingual preparation designed to prevent recurrent respiratory infectious diseases, reduces the infection rate in patients with recurrent respiratory tract infections. On the other hand, mesenchymal stem cells (MSCs) are key cell components that contribute to the maintenance of tissue homeostasis and exert both immunostimulatory and immunosuppressive functions. Herein, we study the effects of MV130 in human MSC functionality as a potential mechanism that contributes to its clinical benefits. We provide evidence that during MV130 sublingual immunization of mice, resident oral mucosa MSCs can take up MV130 components and their numbers remain unchanged after vaccination, in contrast to granulocytes that are recruited from extramucosal tissues. MSCs treated in vitro with MV130 show an increased viability without affecting their differentiation potential. In the short-term, MSC treatment with MV130 induces higher leukocyte recruitment and T cell expansion. In contrast, once T-cell activation is initiated, MV130 stimulation induces an up-regulated expression of immunosuppressor factors in MSCs. Accordingly, MV130-primed MSCs reduce T lymphocyte proliferation, induce the differentiation of dendritic cells with immunosuppressive features and favor M2-like macrophage polarization, thus counterbalancing the immune response. In addition, MSCs trained with MV130 undergo functional changes, enhancing their immunomodulatory response to a secondary stimulus. Finally, we show that MSCs are able to uptake, process and retain a reservoir of the TLR ligands derived from MV130 digestion which can be subsequently transferred to dendritic cells, an additional feature that also may be associated to trained immunity.

Evidence that a primary anti-viral stimulation of the immune response by OM-85 reduces susceptibility to a secondary respiratory bacterial infection in mice

BACKGROUND

Viral respiratory infections may promote bacterial super-infection decreasing the host immune response efficiency. However, using a mice model we recently demonstrated that preventive treatment with the bacterial extract OM-85 reduces the susceptibility to a secondary Streptococcus (S.) pneumoniae infection after influenza virus (I.V.) challenge.

METHODS

To better characterize the efficacy of OM-85 against S. pneumoniae super-infection, a post-hoc analysis was conducted, comparing efficacy (survival) and morbidity signs (clinical score, body temperature and weight loss) in the OM-85 and the control (BLANC) groups of mice after: a) I.V. infection; b) primary S. pneumoniae infection and c) post-I.V. S. pneumoniae super-infection.

RESULTS

After a sublethal I.V. dose, all mice stayed alive at day 5 and no differences in morbidity signs were detected between the OM-85 and the BLANC groups. However, OM-85 pretreatment led to a significantly reduction of the viral load in the lung on day 5 post viral infection and, on day 10, reduced neutrophilic inflammation while increasing influenza-specific CD8 + T-cell proportion in the airways. Conversely to viral infection, exposure to S. pneumoniae induced a dramatic reduction of survival, with no mice surviving on day 3 post infection in the BLANC group, whereas a partial protective effect was observed in OM-85 pre-treated mice (20% of mice surviving at day 3, and 10% at day 4 and 5). The morbidity data substantiated the survival results. Interestingly, in the "super-infection" study, when mice were exposed to a sublethal I.V. dose followed by a secondary S. pneumoniae infection, all mice died by day 4 in the BLANC group. In contrast, in the OM-85 treated group, the survival rate was 70% at day 4 and still 50% at day 5, with positive effects on the clinical scores and on the body temperature already detectable at days 1 and 2.

CONCLUSIONS

The efficacy of OM-85 pre-treatment against S. pneumoniae super-infection reflects a strong and immediate immune reaction from the host, an event that can be explained in part by a "non-specific" activation of the immune system, a positive "immune effect" of the general OM-85- induced immune response against I.V.

Bacterial Etiology of Lower Respiratory Tract Infections and Their Antimicrobial Susceptibility

BACKGROUND

Lower respiratory tract infection (LRTI) is one of the common major health problems in Nigeria causing morbidity and mortality. The study was conducted to determine the current trends of bacterial etiology of LRTIs among patients who attended the University of Nigeria Teaching Hospital (UNTH) and their antimicrobial susceptibility profile with special interest on pandrug resistance.

MATERIALS AND METHODS

The study was conducted between February 2014 and June 2016 in the bacteriology laboratory of UNTH. Sputum samples of 954 patients with suspected LRTIs were received, after obtaining patients' informed consent and ethical clearance from the UNTH. The samples were collected and processed according to standard laboratory procedures.

RESULTS

The mean age of the patients was 42.6 ± 16.8 years. Of the total 954 sputum samples, 431 (45.2%) were positive for micro-organisms. A single, unique pathogen was recovered in 415 patients (96.3%), and 16 (3.7%) were polymicrobial. The most predominant single pathogen was Klebsiella pneumoniae, 215 (49.9%), and the most prevalent bacterial combination was Klebsiella spp and Pseudomonas aeruginosa, 6 (1.4%). Antimicrobial susceptibility testing shows that most isolates of K pneumoniae were susceptible to imipenem (94.8%). Among the bacteria, Escherichia coli (13.3%) ranked highest, followed by P aeruginosa (12.5%), and the least was Staphylococcus aureus (2.1%).

CONCLUSIONS

Knowledge of the diversity of pathogens responsible for LRTIs and their susceptibility patterns to antibiotics, as well as antibiotic resistance surveillance, are important in the effective management of LRTI with prompt clinical and laboratory diagnosis along with appropriate treatment strategies.

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.

Urine Club Cell 16-kDa Secretory Protein and Childhood Wheezing Illnesses After Lower Respiratory Tract Infections in Infancy

Background: Infants with lower respiratory tract infections (LRTIs) are at an increased risk of developing childhood wheezing illnesses (including asthma), but it is not currently possible to predict those at risk for these long-term outcomes. The current objective was to examine whether urine levels of club cell 16-kDa secretory protein (CC16) at the time of an infant LRTI are associated with the development of childhood wheezing illnesses. Methods: Prospective study of 133 previously healthy infants enrolled during a healthcare visit for a LRTI and followed longitudinally for childhood wheezing illnesses. Urine levels of CC16 at the time of enrollment were measured after validating a commercially available enzyme-linked immunosorbent assay kit for serum. The outcome of interest was parental report of subsequent childhood wheeze (defined as ≥1 episode of wheezing following the initial LRTI) at the 1-year follow-up visit. Logistic regression was used for the main analysis. Results: The median (interquartile range) urine levels of CC16 (ng/mg of creatinine) at the time of an infant LRTI were 11.1 (7.7-20.1) for infants with subsequent childhood wheeze and 13.4 (8.3-61.1) for those without (p = 0.11). In the main multivariate analysis using a logarithmic transformation of the urine levels of CC16, a twofold increase in urine levels of CC16 was associated with ∼30% decreased odds (OR = 0.74 [95% confidence interval (CI) 0.56-0.98], p = 0.04) of subsequent childhood wheeze after adjustment for potential confounders. Conclusions: An inverse association was found between urine levels of CC16 at the time of an infant LRTI and the odds of subsequent childhood wheeze. Urine CC16 may be a useful biomarker of the development of childhood wheezing illnesses after LRTIs in infancy.

In vitro activity of levofloxacin against lower respiratory tract pathogens

Background:

Considerable morbidity and mortality are associated with lower respiratory tract infections (LRTIs) that put a considerable strain on the health budget. Selection of appropriate antibiotics as empirical therapy maximizes positive patient outcomes, and that depends on regular surveillance of infective agents and their antibiograms, which vary according to the geographical areas.

Aim:

The aim was to study the drug susceptibility pattern of the isolated pathogens of the respiratory tract infections.

Settings and Design:

Retrospective study for a period of 1-year 3 months from January 2013 to March 2014 at a Tertiary Care Hospital.

Materials and Methods:

Eleven hundred and eighty-four sputum samples from both outdoor and indoor patients with symptoms of LRTI were processed, and antibiotic sensitivity test was done to commonly used antibiotics. Descriptive statistics was used to analyze the data.

Results:

Among 502 quality sputum samples, 312 (62.15%) samples showed growth of pathogenic bacteria. The most common pathogens were Klebsiella spp. (38.14%), Moraxella spp. (16.02%), Streptococcus pneumoniae (14.10%), Pseudomonas spp. (9.93%), S. aureus (9.29%). It was found that the overall susceptibility pattern was <50% for amoxicillin, amoxicillin-clavulanic acid, cefuroxime, cotrimoxazole and erythromycin whereas for cefotaxime, cefixime, and cefoperazone-sulbactum it was 60.08%, 51.59%, 69.04%, respectively. The susceptibility to ciprofloxacin, ofloxacin, and levofloxacin were 66.67%, 70.19% and 83.33%, respectively.

Conclusion:

Klebsiella spp. was the most common LRTI pathogen. There was limited activity of amoxicillin, amoxicillin-clavulanic acid, cefuroxime, cotrimoxazole and erythromycin for the treatment of LRTI whereas levofloxacin, (being an oral drug with good compliance) had good activity against respiratory pathogens and could be used for empiric treatment in LRTI.

Pneumococcal lower respiratory tract infections in adults: an observational case-control study in primary care in Belgium

Background

Serious lower respiratory tract infections (SLRTIs), especially Streptococcus pneumoniae (SP)-related pneumonia cause considerable morbidity and mortality. Chest imaging, sputum and blood culture are not routinely obtained by general practitioners (GPs). Antibiotic therapy is usually started empirically. The BinaxNOW® and Urine Antigen Detection (UAD) assays have been developed respectively to detect a common antigen from all pneumococcal strains and the 13 pneumococcal serotypes present in the vaccine Prevenar 13® (PCV13).

Methods

OPUS-B was a multicentre, prospective, case-control, observational study of patients with SLRTI in primary care in Belgium, conducted during two winter seasons (2011–2013). A urine sample was collected at baseline for the urine assays. GPs were blinded to the results. All patients with a positive BinaxNOW® test and twice as much randomly selected BinaxNOW® negative patients were followed up. Recorded data included: socio-demographics, medical history, vaccination history, clinical symptoms, CRB-65 score, treatments, hospitalization, blood cultures, healthcare use, EQ-5D score. The objectives were to evaluate the percentage of SP SLRTI within the total number of SLRTIs, to assess the percentage of SP serotypes and to compare the burden of disease between pneumococcal and non-pneumococcal SLRTIs.

Results

There were 26 patients with a BinaxNOW® positive test and 518 patients with a BinaxNOW® negative test. The proportion of pneumococcal SLRTI was 4.8 % (95 % CI: 3.1 %–7.2 %). Sixty-eight percent of positive cases showed serotypes represented in PCV13. In the BinaxNOW-positive patients, women were more numerous, there was less exposure to young children, seasonal influenza vaccination was less frequent, COPD was more frequent, the body temperature and the number of breaths per minute were higher, the systolic blood pressure was lower, the frequency of sputum, infiltrate, chest pain, muscle ache, confusion/disorientation, diarrhoea, pneumonia and exacerbations of COPD was more frequent, EQ-5D index and VAS scale were lower, the number of visits to the GP, of working days lost and of days patients needed assistance were higher.

Conclusions

SP was responsible for approximately 5 % of SLRTIs observed in primary care in Belgium. Pneumococcal infection was associated with a significant increase in morbidity. Sixty-eight percent of serotypes causing SLRTI were potentially preventable by PCV13.

Predictors of viral pneumonia in patients with community-acquired pneumonia

BACKGROUND

Viruses are increasingly recognized as major causes of community-acquired pneumonia (CAP). Few studies have investigated the clinical predictors of viral pneumonia, and the results have been inconsistent. In this study, the clinical predictors of viral pneumonia were investigated in terms of their utility as indicators for viral pneumonia in patients with CAP.

METHODS

Adult patients (≥ 18 years old) with CAP, tested by polymerase chain reaction (PCR) for respiratory virus, at two teaching hospitals between October 2010 and May 2013, were identified retrospectively. Demographic and clinical data were collected by reviewing the hospital electronic medical records.

RESULTS

During the study period, 456 patients with CAP were identified who met the definition, and 327 (72%) patients were tested using the respiratory virus PCR detection test. Viral pneumonia (n = 60) was associated with rhinorrhea, a higher lymphocyte fraction in the white blood cells, lower serum creatinine and ground-glass opacity (GGO) in radiology results, compared to non-viral pneumonia (n = 250) (p < 0.05, each). In a multivariate analysis, rhinorrhea (Odd ratio (OR) 3.52; 95% Confidence interval (CI), 1.58-7.87) and GGO (OR 4.68; 95% CI, 2.48-8.89) were revealed as independent risk factors for viral pneumonia in patients with CAP. The sensitivity, specificity, positive- and negative-predictive values (PPV and NPV) of rhinorrhea were 22, 91, 36 and 83%: the sensitivity, specificity, PPV and NPV of GGO were and 43, 84, 40 and 86%, respectively.

CONCLUSION

Symptom of rhinorrhea and GGO predicted viral pneumonia in patients with CAP. The high specificity of rhinorrhea and GGO suggested that these could be useful indicators for empirical antiviral therapy.

Enhanced Mucosal Antibody Production and Protection against Respiratory Infections Following an Orally Administered Bacterial Extract

Secondary bacterial infections following influenza infection are a pressing problem facing respiratory medicine. Although antibiotic treatment has been highly successful over recent decades, fatalities due to secondary bacterial infections remain one of the leading causes of death associated with influenza. We have assessed whether administration of a bacterial extract alone is sufficient to potentiate immune responses and protect against primary infection with influenza, and secondary infections with either Streptococcus pneumoniae or Klebsiella pneumoniae in mice. We show that oral administration with the bacterial extract, OM-85, leads to a maturation of dendritic cells and B-cells characterized by increases in MHC II, CD86, and CD40, and a reduction in ICOSL. Improved immune responsiveness against influenza virus reduced the threshold of susceptibility to secondary bacterial infections, and thus protected the mice. The protection was associated with enhanced polyclonal B-cell activation and release of antibodies that were effective at neutralizing the virus. Taken together, these data show that oral administration of bacterial extracts provides sufficient mucosal immune stimulation to protect mice against a respiratory tract viral infection and associated sequelae.

Microbiological profile of lower respiratory tract infections in neurological intensive care unit of a tertiary care center from Central India

Background:

Lower respiratory tract infections (LRTI's) are the most frequent infections among patients in intensive care units. The consequences of increased drug resistance are far reaching since bacterial infection of the lower respiratory tract (LRT) is a major cause of death from infectious disease.

Objective:

The study was conducted with the aim of determining the bacterial etiology of LRTI in the neuro intensive care unit (NICU) as well as to update the clinicians with the various antimicrobial alternatives available in the treatment of LRTI.

Subjects and Methods:

The study was conducted for the period of 3 years from January 2010 to December 2012 in the Microbiology Department of a Teaching Tertiary Care Hospital. The LRT specimens from 230 patients admitted in a NICU during the study period were processed. Following culture, the isolated organisms were identified and antimicrobial sensitivity was performed by standard methods.

Results:

Out of the 230 LRT specimens evaluated, 198 (86.08%) were culture positive. A total of 254 pathogens were recovered with a predominance of Gram-negative isolates (n = 243; 96.05%) Pseudomonas aeruginosa was the most dominant pathogen followed by Klebsiella pneumoniae. Alarmingly high percentage of extended spectrum beta-lactamase and methicillin resistant Staphylococcus aureus isolates were detected. The resistance to cephalosporins, aminoglycosides and carbapenem were remarkable.

Conclusions:

Therefore, we can conclude that for effective management of LRTI's, an ultimate and detailed bacteriological diagnosis and susceptible testing is required to overcome global problem of antibiotic resistance.

A randomized controlled clinical trial of levofloxacin 750 mg versus 500 mg intravenous infusion in the treatment of community-acquired pneumonia

The objective of this study was to compare the efficacy and safety of levofloxacin 750 mg for 5 days versus 500 mg for 7-14 days intravenous (IV) in the treatment of community-acquired pneumonia (CAP). This clinical trial was the first of its kind conducted in Chinese people and also in Asian population. A total of 241 were enrolled and randomized to 750 mg group (n = 121) or 500 mg (n = 120) group from 10 study centers. The median treatment duration was 5.0 days in 750 mg and 9.0 days in 500 mg group. The median total dose was 3750 mg in 750 mg and 4500 mg in 500 mg group. The bacterial eradication rate was 100% in both groups. The overall efficacy rate in 750 mg group was 86.2% (94/109), and 84.7% (94/111), in 500 mg group of full analysis set visit 4, 95% confidence interval of 1.6% (-7.8-10.9%); the statistical results showed that 750 mg group was non-inferior to 500 mg group. The most common clinical adverse drug reactions were injection site adverse reactions in both 750 mg group and 500 mg group; the other common adverse drug reactions were insomnia, nausea, skin rash, etc. The most common drug-related laboratory abnormalities were neutrophil percentage decreased, decreased white blood cell count, alanine aminotransferase, and aspartate aminotransferase elevation in both 750 mg group and 500 mg group. Most of adverse drug reactions were mild in severity and well-tolerated. In summary, the regimen of levofloxacin 750 mg IV for 5 days was at least as effective and well tolerated as 500 mg IV for 7-14 days for the treatment of CAP.

Etiological analysis and predictive diagnostic model building of community-acquired pneumonia in adult outpatients in Beijing, China

BACKGROUND

Etiological epidemiology and diagnosis are important issues in adult community-acquired pneumonia (CAP), and identifying pathogens based on patient clinical features is especially a challenge. CAP-associated main pathogens in adults include viruses as well as bacteria. However, large-scale epidemiological investigations of adult viral CAP in China are still lacking. In this study, we analyzed the etiology of adult CAP in Beijing, China and constructed diagnostic models based on combinations of patient clinical factors.

METHODS

A multicenter cohort was established with 500 adult CAP outpatients enrolled in Beijing between November 2010 to October 2011. Multiplex and quantitative real-time fluorescence PCR were used to detect 15 respiratory viruses and mycoplasma pneumoniae, respectively. Bacteria were detected with culture and enzyme immunoassay of the Streptococcus pneumoniae urinary antigen. Univariate analysis, multivariate analysis, discriminatory analysis and Receiver Operating Characteristic (ROC) curves were used to build predictive models for etiological diagnosis of adult CAP.

RESULTS

Pathogens were detected in 54.2% (271/500) of study patients. Viruses accounted for 36.4% (182/500), mycoplasma pneumoniae for 18.0% (90/500) and bacteria for 14.4% (72/500) of the cases. In 182 of the patients with viruses, 219 virus strains were detected, including 166 single and 53 mixed viral infections. Influenza A virus represented the greatest proportion with 42.0% (92/219) and 9.1% (20/219) in single and mixed viral infections, respectively. Factors selected for the predictive etiological diagnostic model of viral CAP included cough, dyspnea, absence of chest pain and white blood cell count (4.0-10.0) × 10(9)/L, and those of mycoplasma pneumoniae CAP were being younger than 45 years old and the absence of a coexisting disease. However, these models showed low accuracy levels for etiological diagnosis (areas under ROC curve for virus and mycoplasma pneumoniae were both 0.61, P < 0.05).

CONCLUSIONS

Greater consideration should be given to viral and mycoplasma pneumoniae infections in adult CAP outpatients. While predictive etiological diagnostic models of viral and mycoplasma pneumoniae based on combinations of demographic and clinical factors may provide indications of etiology, diagnostic confirmation of CAP remains dependent on laboratory pathogen test results.

Microbiological diagnosis of community-acquired respiratory tract infections by nucleic acid detection

BACKGROUND

Microbiological diagnostic procedures have changed significantly over the last decade. Initially the implementation of the polymerase chain reaction (PCR) resulted in improved detection tests for microbes that were difficult or even impossible to detect by conventional methods such as culture and serology, especially in community-acquired respiratory tract infections (CA-RTI). A further improvement was the development of real-time PCR, which allows end point detection and quantification, and many diagnostic laboratories have now implemented this powerful method.

OBJECTIVE

At present, new performant and convenient molecular tests have emerged targeting in parallel many viruses and bacteria responsible for lower and/or upper respiratory tract infections. The range of test formats and microbial agents detected is evolving very quickly and the added value of these new tests needs to be studied in terms of better use of antibiotics, better patient management, duration of hospitalization and overall costs.

CONCLUSIONS

Molecular tools for a better microbial documentation of CA-RTI are now available. Controlled studies are now required to address the relevance issue of these new methods, such as, for example, the role of some newly detected respiratory viruses or of the microbial DNA load in a particular patient at a particular time. The future challenge for molecular diagnosis will be to become easy to handle, highly efficient and cost-effective, delivering rapid results with a direct impact on clinical management.

Synergistic and feedback signaling mechanisms in the regulation of inflammation in respiratory infections

Pneumonia, the most typical and frequent lower respiratory tract infection (LRTI), is a leading cause of health problems in the United States. Bacteria represent the most prevailing cause of pneumonia in both children and adults. Although pneumonia with a single bacterial infection is common, a significant portion of patients with pneumonia is polymicrobial. This infection is often complexed with other physiological factors such as cytokines and growth factors. Nontypeable Haemophilus influenzae (NTHi) is the most frequently recovered Gram-negative bacterial pathogen in the respiratory system and induces strong inflammatory responses. NTHi also synergizes with other respiratory pathogens, such as Streptococcus pneumoniae and respiratory viruses and pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α). It is noteworthy that NTHi not only synergizes with growth factors such as transforming growth factor-beta (TGF-β), but also utilizes growth factor receptors such as TGF-β receptor and epidermal growth factor receptor (EGFR), to enhance inflammatory responses. Although appropriate inflammation is a protective response against invading pathogens, an uncontrolled inflammatory response is often detrimental to the host. Thus, inflammation must be tightly regulated. The human immune system has evolved strategies for controlling overactive inflammatory response. One such important mechanism is via regulation of negative feedback regulators for inflammation. CYLD, a multifunctional deubiquitinase, was originally reported as a tumor suppressor, but was recently identified as a negative regulator for nuclear factor-kappa B (NF-κB) signaling. It is induced by NTHi and TNF-α via a NF-κB-dependent mechanism, thereby serving as an inducible negative feedback regulator for tightly controlling inflammation in NTHi infection.

Resource use and costs of treating acute cough/lower respiratory tract infections in 13 European countries: results and challenges

The objectives of this study were to estimate the resource use and cost of treating acute cough/lower respiratory tract infection (acute cough/LRTI) in 13 European countries, to explore reasons for differences in cost and to document the challenges that researchers face when collecting information on cost alongside multinational studies. Data on resource use and cost were collected alongside an observational study in 14 primary care networks across 13 European countries and a mean cost was generated for each network. The results show that the mean cost (standard deviation) of treating acute cough/LRTI in Europe ranged from euro23.88 (34.67) in Balatonfüred (Hungary) to euro116.47 (34.29) in Jonkoping (Sweden). The observed differences in costs were statistically significant (P < 0.01). Major cost drivers include general practitioner visits and drug costs in all networks, whilst differences in health systems and regional factors could account for differences in cost between networks. The major barrier to conducting multinational cost studies are barriers associated with identifying cost information.

[Incidence rate of community acquired pneumonia in a population cohort registered in BIFAP]

OBJECTIVE

To estimate the incidence rate (IR) of community acquired pneumonia (CAP) using the information in the Primary Healthcare database in Spain.

DESIGN

Retrospective study (2003-2007) using the information registered in the Database for Pharmaco-Epidemiological Research in Primary Care (BIFAP).

STUDY POPULATION

Subjects aged 20 to 79 years old, were followed up until the occurrence of a pneumonia episode, death, age of 80, or the end of the study, whichever came first. CASE SELECTION: A computerised search was performed to detect suggestive cases of pneumonia using ICPC codes (International Classification of Primary Care) and free text. The computerised histories were manually reviewed in order to identify those cases fulfilling the CAP's determined definition. ANALYSE: IR of pneumonia was computed by age, sex and season. The percentage of hospitalisation was estimated. These results were compared with the IR from the United Kingdom using THIN database (The Health Improvement Network).

RESULTS

IR of CAP was 2.69 per 1000 persons-year (IR women=2.29; IR men=3.16) with BIFAP database, and 32 % of the CAP cases were hospitalised. In United Kingdom, IR was 1.07 per 1000 persons-year (IR women=0.93; IR men=1.22) and 17% of CAP were hospitalised.

CONCLUSION

The BIFAP computerised Primary Care database is useful to estimate the incidence rate of CAP in Spain, as well as to compare the results with those obtained using other European computerised Primary Care databases.

Levofloxacin for the treatment of pneumonia caused by Streptococcus pneumoniae including multidrug-resistant strains: pooled analysis

OBJECTIVE

To determine the clinical and microbiologic efficacy of levofloxacin for the treatment of subjects with pneumonia caused by multidrug-resistant (MDR) Streptococcus pneumoniae (MDRSP) and non-MDRSP strains.

RESEARCH DESIGN AND METHODS

A pooled analysis was conducted using data from ten clinical studies in pneumonia: five comparative studies and five noncomparative studies conducted from 1992 to 2002. This analysis included data from levofloxacin-treated subjects with S. pneumoniae isolated at study entry. Susceptibility of S. pneumoniae isolated from subjects at study entry was determined against representative agents from five antimicrobial classes: tetracyclines, sulfonamides, second-generation cephalosporins, penicillins, and macrolides. Isolates were classified as MDRSP (based on resistance to two or more antimicrobial classes) or non-MDRSP (intermediate resistance or susceptible to all classes or resistant to 1 antimicrobial class). Clinical and microbiologic efficacy of levofloxacin (i.v., p.o., or i.v./p.o. for 5 to 14 days) in the microbiologically evaluable population was determined at post-therapy; a test for homogeneity of the odds ratio of the difference in clinical success for comparative versus noncomparative studies was performed.

MAIN OUTCOME MEASURES AND RESULTS

The main outcome measures were clinical success rates and microbiologic eradication rates of 419 microbiologically evaluable levofloxacin-treated subjects with MDRSP or non-MDRSP. Clinical success rates were 96.3% (52/54) and 95.1% (347/365), respectively (difference -1.2; 95% confidence interval [CI]: -6.7, 4.3). Similarly, per pathogen microbiologic eradication rates for MDRSP and non-MDRSP were 96.3% (52/54) and 95.6% (350/366), respectively (difference -0.7; 95% CI: -6.1, 4.8). Study limitations include the use of data from comparative and noncomparative studies. A test for homogeneity of the odds ratios for clinical success in comparative versus noncomparative studies showed no significant difference (p = 0.27).

CONCLUSIONS

These data support the use of levofloxacin for patients with community-acquired pneumonia caused by S. pneumoniae, including MDR strains.

In-vitro bioactivity of Venda medicinal plants used in the treatment of respiratory conditions

Infectious diseases, especially those affecting the respiratory tract, represent a critical problem to health. Crude methanol and water extracts of 10 Venda plants reported to be used ethnomedically in the treatment of respiratory conditions were assessed for their antimicrobial activity against standard strains and clinical isolates of Candida albicans, Haemophilis influenzae, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium smegmatis using the disc diffusion assay. Four of the 10 plants tested possessed antimicrobial activity, but no activity against K. pneumoniae was observed. Minimum inhibitory concentrations, as determined by the broth microdilution assay, showed three plants, Securidaca longepedunculata, Syzygium cordatum, and Tabernaemontana elegans, to possess MICs ≤ 1 mg/mL. Phytochemical screening, performed by separation on thin layer chromatography using a variety of mobile phases and visualization with spray reagents as well as UV light showed various classes of compounds in the active extracts. Some of these have been associated with antioxidant activity, as confirmed in this study. Moreover, these extracts showed toxicity in vitro to lymphocytes. Although three plant species with significant antimicrobial activity were identified, there is a need for further scientific evaluation regarding identification of the bioactive constituents, as well as their toxicity.

Antibacterial resistance patterns in Streptococcus pneumoniae isolated from elderly patients: PROTEKT years 1-5 (1999-2004)

The antibacterial susceptibilities of 6,646 Streptococcus pneumoniae isolates collected in 38 countries from patients >or=65 years of age with community-acquired respiratory tract infections (RTIs) during years 1-5 of the PROTEKT study (1999-2004) were analysed. Rates of erythromycin resistance (36.0%), penicillin non-susceptibility (31.3%; 20.2% resistant plus 11.1% intermediately susceptible) and resistance to multiple antibacterials (37.2%) were stable over the 5 years. The most common macrolide resistance mechanism was erm(B) (61.4%); erm(B)+mef(A) strains increased from 5.4% (year 1) to 7.4% (year 5) (P=0.037). Overall, 37.2% of isolates exhibited resistance to two or more antibacterials, including 15.9% resistant to both penicillin and erythromycin. Antibacterial resistance was highest in the Far East. Telithromycin resistance was rare (0.12%). Appropriate alternative empirical first-line therapies may be required for treating community-acquired RTIs in the elderly.

A survey of antibiotic resistance in Streptococcus pneumoniae and Haemophilus influenzae in Turkey, 2004–2005

OBJECTIVES

To determine the prevalence of antimicrobial resistance among Streptococcus pneumoniae and Haemophilus influenzae isolated in Turkey as part of Survey Of Antibiotic Resistance, a surveillance programme in the Africa and Middle East region examining the antimicrobial susceptibility of key bacterial pathogens involved in community-acquired respiratory tract infections (CARTIs).

METHODS

Susceptibility was evaluated against a range of antimicrobial agents using disc diffusion and Etest methods.

RESULTS

Six centres in five cities collected 301 S. pneumoniae and 379 H. influenzae isolates between October 2004 and November 2005. Among S. pneumoniae, the prevalence of isolates with intermediate susceptibility (MICs 0.12-1 mg/L) and resistance to penicillin (MICs >or=2 mg/L) was 24.6% and 7.6%, respectively; there was a wide variation between cities (2.4% to 36.9% intermediate and 0% to 23.8% resistant phenotypes). Macrolide-azalide resistance rates exceeded those of penicillin resistance in all cities. Overall, 5.0% of isolates were co-resistant to penicillin and erythromycin and 10.0% were multidrug-resistant (joint resistance to erythromycin, co-trimoxazole and tetracycline). Agents tested to which over 90% of countrywide S. pneumoniae isolates remained susceptible were amoxicillin/clavulanate (98.7%), chloramphenicol (94.7%) and cefprozil (90.6%). Overall, the percentage of H. influenzae isolates producing beta-lactamase was 5.5%, differing widely across the country with the highest prevalence of beta-lactamase production detected in Trabzon (14.0%) and no beta-lactamase-positive isolates found in Izmir. H. influenzae had the highest per cent susceptibility to amoxicillin/clavulanate (99.5%) and ofloxacin (99.2%) while >20% were resistant to co-trimoxazole.

CONCLUSIONS

Prevalence of penicillin and macrolide-azalide resistance among S. pneumoniae appears to be on the increase in Turkey while overall beta-lactamase production in H. influenzae remains relatively low. To adequately monitor the spread of drug-resistant phenotypes among these two important CARTI pathogens, ongoing collection of resistance surveillance data is required-where possible locally as resistance patterns can vary substantially between cities and institutions.

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

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

Improved diagnosis of the etiology of community-acquired pneumonia with real-time polymerase chain reaction

BACKGROUND

Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality. Polymerase chain reaction (PCR) has been shown to be more sensitive than current standard microbiological methods and, therefore, may improve the accuracy of microbiological diagnosis for patients with CAP.

METHODS

Conventional detection techniques and multiplex real-time PCR for atypical bacteria and respiratory viruses were performed on samples collected from 105 adults enrolled in a prospective study. An infiltrate was visible on each patient's chest radiograph, and a pneumonia severity index score was determined for each patient.

RESULTS

Microbiological diagnoses were determined for 52 (49.5%) of 105 patients by conventional techniques and for 80 (76%) of 105 patients by real-time PCR. The time to obtain the result of real-time PCR could be reduced to 6 h. PCR methodology was significantly more sensitive for the detection of atypical pathogens and viruses (P< or =.001). Respiratory viral infections and mixed infections were detected in 15 (14.2%) and 3 (2.8%) of 105 patients, respectively, by conventional methods, but were detected in 59 (56.2%) and 28 (26.5%) of 105, respectively, by real-time PCR. Presence of a mixed infection was significantly associated with severe pneumonia (P=.002). Human rhinoviruses and coronaviruses, OC43 and 229E, were frequently identified pathogens.

CONCLUSIONS

The combined real-time PCR assay is more sensitive for diagnosis of the main viruses and atypical bacteria that cause CAP compared with conventional methods, and obtains results in a clinically relevant time period.

Treatment of acute exacerbation of severe-to-very severe COPD with azithromycin in patients vaccinated against Streptococcus pneumoniae

Sixty-five consecutive eligible adult patients, who were treated as outpatients for stable severe-to-very severe COPD, were enrolled in the study. All of them received 23-valent pneumococcal capsular polysaccharide vaccine intramuscularly. Patients were seen monthly, as well as whenever they had symptoms suggestive of an exacerbation, at our outpatient clinic. Eighteen out of 65 patients suffered from acute exacerbation (AECOPD). Three of these patients presented two episodes of AECOPD. Patients with an acute exacerbation of COPD received azithromycin 500 mg/day once daily for 3 days and a short course of oral prednisolone 25 mg/die. In 16 cases, a single species was isolated, while in the remaining 5 cases at least two species were recovered. Clinical cure or improvement at the end of therapy (3-5 days post-therapy) was reported in 17 episodes of AECOPD with no relapse at the late post-therapy (10-14 days after the completion of treatment). Bacteriologic eradication or presumptive eradication rates at the end of therapy were 86% (24 out of 28 isolates). Azithromycin eradicated all isolates of Haemophilus influenzae, Moraxella catarrhalis, H. parainfluenzae, Klebsiella pneumoniae, and Klebsiella spp. isolated at baseline. Eradication of Sta aureus occurred in 1 of 3 isolates whereas azithromycin was unable to eradicate Pseudomonas aeruginosa isolates. Our data seem to indicate that pneumococcal vaccination reduces the possibility that an AECOPD is caused by Streptococcus pneumoniae. This finding allows the use of antibiotics such as azithromycin, which, otherwise, should be avoided because of resistances.

Optimizing fluoroquinolone utilization in a public hospital: a prospective study of educational intervention

Fluoroquinolone (FQ) utilization should be optimized, with the aim of controlling both multidrug-resistant bacteria and costs. In the present study, the appropriateness of FQ prescriptions for urinary tract infections (UTIs) before and after an educational intervention was examined prospectively. FQ-prescribing physicians received oral and written guidelines between the two phases of the study. All patients admitted to Saint-Antoine University Hospital (Paris) and treated with FQs for UTIs during the study period were included. The main outcome measures of the appropriateness of FQ prescriptions were based on the principles of Antibiotic Utilization Review. The study involved 127 patients. The main prescribing errors before the intervention were wrong routes of administration and failure to take into account antibiotic susceptibility results. The rate of erroneous prescriptions fell by 74.4% after intervention. About 71% of the improvement can be attributed to the intervention (71.4%; 95% confidence interval, 39.3-86.8). The intervention had an overall positive impact on FQ prescription quality. The decrease in inappropriate prescriptions was due mainly to the use of antibiotic susceptibility results (23% vs. 11.5%, P<0.05) and better consideration of indications (18.9% vs. 3.8%; P<0.05). Future educational interventions will cover other indications and will take into account costs and local antimicrobial susceptibility patterns.

In vitro activities of novel 2-fluoro-naphthyridine-containing ketolides

In vitro activities of erythromycin A, telithromycin, and two investigational ketolides, JNJ-17155437 and JNJ-17155528, were evaluated against clinical bacterial strains, including selected common respiratory tract pathogens. Against 46 macrolide-susceptible and -resistant Streptococcus pneumoniae strains, the MIC(90) (MIC at which 90% of the isolates tested were inhibited) of the investigational ketolides was 0.25 microg/ml, twofold lower than that of telithromycin and at least 64-fold lower than that of erythromycin A. Against erm(B)-containing pneumococci, the MIC(90) of all the ketolides was 0.06 microg/ml. The MIC(90) of the investigational ketolides against mef(A)-containing pneumococci or pneumococci with both mef(A) and erm(B) was 0.25 microg/ml, two-and fourfold lower, respectively, than that of telithromycin. In contrast, the MICs of the investigational ketolides against macrolide-resistant S. pneumoniae strains with ribosomal mutations were similar to or, in some cases, as much as eightfold higher than those of telithromycin. Against Haemophilus influenzae, MICs of all the ketolides were < or =2 microg/ml. Against three Moraxella catarrhalis isolates, the MIC of the ketolides was 0.25 microg/ml. The ketolides inhibited in vitro protein synthesis, with 50% inhibitory concentrations ranging from 0.23 to 0.27 microM. In time-kill studies against macrolide-susceptible and erm- or mef-containing pneumococci, the ketolides were bacteriostatic to slowly bactericidal, with 24-h log(10) decreases ranging from 2.0 to 4.1 CFU. Intervals of postantibiotic effects for the ketolides against macrolide-susceptible and -resistant S. pneumoniae were 3.0 to 8.1 h.

Antimicrobial susceptibility among community-acquired respiratory tract pathogens in the USA: data from PROTEKT US 2000–01

OBJECTIVES

The PROTEKT US surveillance program (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin in the United States) commenced in 2000 to document the emergence and spread of antimicrobial resistance among respiratory tract pathogens in the United States.

METHODS

During 2000-2001, 206 centers from 154 cities/metropolitan areas collected 16,727 clinical isolates (Streptococcus pneumoniae, n=10103, Streptococcus pyogenes, n=3918, Haemophilus influenzae, n=2706).

RESULTS

Among S. pneumoniae isolates, 38.9% showed decreased susceptibility to penicillin (12.5% intermediate, 26.4% resistant) with marked geographical variability. The erythromycin resistance rate was 31.0% and highly correlated with penicillin resistance. The rate of fluoroquinolone resistance was 0.8%. Telithromycin was nearly uniformly active against S. pneumoniae (MIC(90) 0.5 mg/l). All isolates of S. pyogenes were penicillin-susceptible, 5.5% were resistant to erythromycin. Telithromycin minimum inhibitory concentrations (MICs) were lower than clindamycin and macrolide MICs against S. pyogenes (MIC(90) 0.03 mg/l versus 0.25 mg/l and 0.12 mg/l, respectively). 28.3% of H. influenzae isolates produced beta-lactamase. Telithromycin activity versus H. influenzae was not affected by beta-lactamase production.

CONCLUSIONS

The PROTEKT US study confirms the widespread prevalence of antimicrobial resistance among common bacterial respiratory pathogens in the US, and re-affirms the importance of continued surveillance to guide optimum empiric therapy for patients with Community-acquired respiratory tract infections (CARTIs). The new ketolide, telithromycin, maintained potent activity against study isolates in vitro and offers promise for the effective treatment of CARTIs.

Current Management Issues Associated with Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is a significant cause of morbidity, mortality, and increased cost. Despite numerous managementguidelines, CAP continues to existas a challenge to the learned clinician. Due to a lack of sensitive diagnostic testing, causative pathogens are often not identified, making most therapy empiric. Increasing levels of bacterial resistance to available antimicrobials worldwide has been implicated in driving up the costs of treatment and adversely effecting clinical outcomes. Pharmacists can be part of the solution by encouraging appropriate antimicrobial selection based on resistance patterns in their communities and ensuring appropriate vaccines are employed to prevent CAP.

High-dose, short-course levofloxacin for community-acquired pneumonia: a new treatment paradigm

Levofloxacin demonstrates concentration-dependent bactericidal activity most closely related to the pharmacodynamic parameters of the ratio of area under the concentration-time curve (AUC) to minimum inhibitory concentration (MIC) and the ratio of peak plasma concentration (C(max)) to MIC. Increasing the dose of levofloxacin to 750 mg exploits these parameters by increasing peak drug concentrations, allowing for a shorter course of treatment without diminishing therapeutic benefit. This was demonstrated in a multicenter, randomized, double-blind investigation that compared levofloxacin dosages of 750 mg per day for 5 days with 500 mg per day for 10 days for the treatment of mild to severe community-acquired pneumonia (CAP). In the clinically evaluable population, the clinical success rates were 92.4% (183 of 198 persons) for the 750-mg group and 91.1% (175 of 192 persons) for the 500-mg group (95% confidence interval, -7.0 to 4.4). Microbiologic eradication rates were 93.2% and 92.4% in the 750-mg and 500-mg groups, respectively. These data demonstrate that 750 mg of levofloxacin per day for 5 days is at least as effective as 500 mg per day for 10 days for treatment of mild-to-severe CAP.

Antimicrobials in acute exacerbations of chronic obstructive pulmonary disease - An analysis of the time to next exacerbation before and after the implementation of standing orders

OBJECTIVE

To compare the mean time to next exacerbation in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) before and after the implementation of standing orders.

SETTING

Tertiary care hospital, Halifax, Nova Scotia, Canada.

POPULATION STUDIED

The records of 150 patients were analyzed, 76 were in the preimplementation group, 74 in the postimplementation group.

INTERVENTION

The management and outcomes of patients admitted with an acute exacerbation of COPD before and after the implementation of standing orders were compared.

DESIGN

A retrospective chart review.

MAIN RESULTS

THERE WAS NO DIFFERENCE IN THE MEAN TIME TO NEXT EXACERBATION BETWEEN TREATMENT GROUPS (PREIMPLEMENTATION GROUP: 310 days, postimplementation group: 289 days, P=0.53). Antibiotics were used in 90% of the cases (preimplementation group: 87%, postimplementation group: 93%). The postimplementation group had a 20% increase in the use of first-line agents over the preimplementation group. Overall, first-line agents represented only 37% of the antibiotic courses.

CONCLUSIONS

The implementation of standing orders encouraged the use of first-line agents but did not influence subsequent symptom resolution, length of hospital stay, or the infection-free interval in patients with acute exacerbations of COPD.

Severe community-acquired pneumonia: what's in a name?

PURPOSE OF REVIEW

Formerly, patients with community-acquired pneumonia admitted to an intensive care unit were considered as having the severe form of the disease. Recently, guidelines have distinguished severe and non-severe community-acquired pneumonia based on clinical definitions. In this review, we describe the different definitions of severe community-acquired pneumonia, and whether a differentiation based on these definitions reflects variation in etiology, risk factors, diagnostic approaches and treatment.

RECENT FINDINGS

New definitions do not seem to accurately identify patients with high risks of mortality; patients not admitted to an intensive care unit could also be diagnosed as having severe community-acquired pneumonia. Host-factors, such as genetic factors and underlying diseases, can influence severity of presentation of community-acquired pneumonia. Distribution of pathogens in severe and non-severe disease forms is comparable. Initial antibiotic therapy in patients with severe disease should provide coverage of Streptococcus pneumoniae and Legionella pneumophila, as delay is associated with worse outcomes. However, recent studies also suggested an additional benefit of atypical coverage in non-severe disease. As a result, initial therapy with a beta-lactam plus a macrolide or an anti-pneumococcal fluoroquinolone is recommended for all patients with community-acquired pneumonia. Furthermore, the value of vaccination against pneumococci to prevent episodes of severe disease is yet unknown.

SUMMARY

As current guidelines do not adequately identify patients with high risk of mortality and intensive care unit admittance, clinical judgment remains important. Based on distribution of pathogens, investigational procedures and therapy recommended in recent guidelines, differentiation between severe and non-severe community-acquired pneumonia does not seem useful. Whether atypical coverage indeed has additional value in non-severe or pneumococcal CAP, however, remains to be determined. In addition, the preventive benefit of influenza and pneumococcal vaccination for development of SCAP awaits further evidence.

Comparative bactericidal activity of fluoroquinolones against clinical isolates resistant to fluoroquinolones

The bactericidal activity of levofloxacin, ciprofloxacin, moxifloxacin and norfloxacin against clinical isolates conventionally classified as resistant to fluoroquinolones were compared at their maximum concentrations in serum, urine (except moxifloxacin) and bronchial mucosa (except norfloxacin). Time killing curves against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Streptococcus pneumoniae were performed. Serum concentrations of the tested drugs were not able to produce a bactericidal effect on fluoroquinolone-resistant strains. In the urine series, levofloxacin was always bactericidal (decrease > or = 3 logs CFU/ml), while norfloxacin and ciprofloxacin were bactericidal on E. coli (both), P. mirabilis (norfloxacin) and P. aeruginosa (ciprofloxacin). In the bronchial mucosa series, S. pneumoniae was rapidly killed by levofloxacin and moxifloxacin, and K. pneumoniae by levofloxacin after 12 hours. In conclusion, the maximum levofloxacin concentrations achievable at certain body sites allowed killing even of strains defined as resistant by conventional breakpoints.

Efficacy and safety of azithromycin vs levofloxacin in the outpatient treatment of acute bacterial exacerbations of chronic bronchitis

STUDY OBJECTIVES

To compare the safety and efficacy of oral azithromycin and levofloxacin in the treatment of outpatients with acute bacterial exacerbations of chronic bronchitis (ABECB).

DESIGN

Randomized, double-blinded, double-dummy, multicenter trial with 1:1 treatment allocation.

SETTING

Outpatient treatment setting.

PATIENTS

Two hundred thirty-five male or female outpatients between the ages of 35 and 75 years who had received a clinical diagnosis of ABECB.

INTERVENTIONS

Blinded treatment with either oral azithromycin, 500 mg on day 1 and 250 mg per day for days 2 to 5, or, oral levofloxacin, 500 mg q24h for 7 days.

RESULTS

Both treatments were well-tolerated, with the majority of adverse events being GI in nature. Favorable clinical outcomes in clinically evaluable patients were demonstrated in 89% of patients receiving azithromycin and in 92% of patients receiving levofloxacin by day 4 of therapy. At day 24, the posttherapy visit, favorable responses were approximately 82% and 86%, respectively, for patients in the two treatment groups. The bacterial eradication rates of respiratory pathogens were 96% for azithromycin and 85% for levofloxacin.

CONCLUSIONS

Despite increasing concerns over macrolide resistance and a higher incidence of Gram-negative pathogens, a standard 5-day course of oral azithromycin was clinically and bacteriologically equivalent to a 7-day course of oral levofloxacin in the treatment of patients with ABECB.

Fluoroquinolone treatment of community-acquired pneumonia: a meta-analysis

OBJECTIVE

To determine the role of newer fluoroquinolones (FQs) for adults with community-acquired pneumonia (CAP) whose level of illness allows treatment with an oral antibiotic.

METHODS

Meta-analysis of randomized controlled trials comparing a macrolide, beta-lactam, or doxycycline antibiotic with a newer oral FQ for the treatment of CAP.

RESULTS

Patients (5118), most of whom were <60 years of age and free of coexisting diseases, were enrolled in 13 studies comparing an oral macrolide or beta-lactam antibiotic with an FQ for the treatment of CAP. No previous study compared doxycycline with an FQ. In the intention-to-treat (ITT) population, no trial demonstrated significant differences between FQs or alternative therapies. Summary estimates showed a statistically significant advantage in favor of the FQs in both the ITT (OR 1.22; 95% CI 1.02 to 1.47; p = 0.03) and evaluable populations (OR 1.37; 95% CI 1.11 to 1.68; p = 0.003). The number needed to treat for an FQ advantage was 33 (95% CI 17 to 362) in the ITT population and 37 (95% CI 22 to 121) in the evaluable population. Treatment failures represented slow symptom resolution; no deaths were reported.

CONCLUSIONS

The newer oral FQs showed modest therapeutic benefit compared with the studied alternative antibiotics in adults with CAP. Based on the number needed to treat from the ITT population as a measure of treatment effect, clinicians must decide whether treating 33 patients with an FQ to prevent a single therapeutic failure with another studied antibiotic warrants use of an agent from that class for an illness with a generally favorable outcome regardless of antibiotic selection, and at a time when FQ resistance may be increasing.