Streptococcus pneumoniae and community-acquired pneumonia: a cause for concern

Prevalence of Penicillin Resistance Among Streptococcus pneumoniae Isolates in a General Hospital in Southwest Saudi Arabia: A Five-Year Retrospective Study

Background The rise in infections caused by penicillin-resistant strains of Streptococcus pneumoniae has become a global concern. However, the magnitude of this problem in Southwest Saudi Arabia has never been investigated. Therefore, this study aims to determine the prevalence of this bacteria in the region using in vitro data. Materials and methods This study retrospectively studied pneumococcal isolates collected by the Microbiology Laboratory of a general hospital in Al Baha, Saudi Arabia, from January 2013 to December 2017. A minimum inhibitory concentration (MIC) ≥ 8 mg/L was used as a cutoff concentration to detect the resistant isolates. Results A total of 201 S. pneumoniae isolates were identified using the VITEK® 2 system (bioMérieux SA, Marcy-l'Étoile, France). Most of these isolates (61%) were obtained from respiratory specimens, including sputum, tracheal aspirates, and bronchoalveolar lavage. Eye swabs accounted for 15% of the isolates, blood samples contributed 12%, ear swabs accounted for 7%, and cerebrospinal fluid (CSF) 3.4%. The resistance of S. pneumoniae during the five years varied from 61% to 76%, with an overall resistance of 70% (141/201). The resistance rate per year was 71% (43/60) in 2013, 76% (35/46) in 2014, 61% (22/36) in 2015, 68% (20/29) in 2016, and 66% (21/30) in 2017. Conclusion The data confirm the presence of penicillin-resistant S. pneumoniae in Southwest Saudi Arabia. Furthermore, the high resistance suggests a potential concern, emphasizing the need for penicillin control, surveillance, and vaccination to address this growing problem.

Microfluidic systems for infectious disease diagnostics

Microorganisms, encompassing both uni- and multicellular entities, exhibit remarkable diversity as omnipresent life forms in nature. They play a pivotal role by supplying essential components for sustaining biological processes across diverse ecosystems, including higher host organisms. The complex interactions within the human gut microbiota are crucial for metabolic functions, immune responses, and biochemical signalling, particularly through the gut-brain axis. Viruses also play important roles in biological processes, for example by increasing genetic diversity through horizontal gene transfer when replicating inside living cells. On the other hand, infection of the human body by microbiological agents may lead to severe physiological disorders and diseases. Infectious diseases pose a significant burden on global healthcare systems, characterized by substantial variations in the epidemiological landscape. Fast spreading antibiotic resistance or uncontrolled outbreaks of communicable diseases are major challenges at present. Furthermore, delivering field-proven point-of-care diagnostic tools to the most severely affected populations in low-resource settings is particularly important and challenging. New paradigms and technological approaches enabling rapid and informed disease management need to be implemented. In this respect, infectious disease diagnostics taking advantage of microfluidic systems combined with integrated biosensor-based pathogen detection offers a host of innovative and promising solutions. In this review, we aim to outline recent activities and progress in the development of microfluidic diagnostic tools. Our literature research mainly covers the last 5 years. We will follow a classification scheme based on the human body systems primarily involved at the clinical level or on specific pathogen transmission modes. Important diseases, such as tuberculosis and malaria, will be addressed more extensively.

Meningitis in critically ill patients admitted to intensive care unit for severe community-acquired pneumococcal pneumonia

BACKGROUND

Although it has been reported that patients with pneumococcal pneumonia may develop meningitis, lumbar puncture is not systematically recommended in these patients, even in patients with associated bacteremia or invasive pneumococcal disease. The aim of this study was to determine the characteristics and outcomes of patients admitted to intensive care unit (ICU) for pneumococcal community-acquired pneumonia who developed meningitis.

METHODS

We retrospectively included all consecutive patients admitted to our ICU from January 2006 to December 2020 for severe pneumococcal community-acquired pneumonia according to American Thoracic Society criteria. Meningitis was defined as pleocytosis > 5 cells/mm3 or a positive culture of cerebrospinal fluid for Streptococcus pneumoniae in lumbar puncture. The primary endpoint was the proportion of patients with meningitis during their ICU stay.

RESULTS

Overall, 262 patients [64(52-75) years old] were included: 154(59%) were male, 80(30%) had chronic respiratory disease, 105(39%) were immunocompromised and 6(2%) were vaccinated against S. pneumoniae. A lumbar puncture was performed in 88(34%) patients with a delay from ICU admission to puncture lumbar of 10.5 (2.8-24.1) h and after the initiation of pneumococcal antibiotherapy in 81(92%) patients. Meningitis was diagnosed in 14 patients: 16% of patients with lumbar puncture and 5% of patients in the whole population. Patients with meningitis had more frequently human immunodeficiency virus positive status (29 vs. 5%, p = 0.02), neurological deficits on ICU admission (43 vs. 16%, p = 0.03) and pneumococcal bacteremia (71 vs. 30%, p < 0.01) than those without. The ICU mortality rate (14 vs. 13%, p = 0.73) and the mortality rate at Day-90 (21 vs. 15%, p = 0.83) did not differ between patients with and without meningitis. The proportion of patients with neurological disorders at ICU discharge was higher in patients with meningitis (64 vs. 23%, p < 0.001) than in those without. The other outcomes did not differ at ICU discharge, Day-30 and Day-90 between the two groups of patients.

CONCLUSION

Meningitis was diagnosed in 16% of patients with severe pneumococcal community-acquired pneumonia in whom a lumbar puncture was performed, was more frequent in patients with pneumococcal bacteremia and was associated with more frequent neurological disorders at ICU discharge. Further studies are needed to confirm these results.

Antibiotic persistence and its impact on the environment

From boon molecules to molecules contributing to rising concern has been the sojourn of antibiotics. The problem of antibiotic contamination has gotten worse due to antibiotics' pervasive use in every aspect of the environment. One such consequence of pollution is the increase in infections with antibiotic resistance. All known antimicrobials being used for human benefit lead to their repetitive and routine release into the environment. The misuse of antibiotics has aggravated the situation to a level that we are short of antibiotics to treat infections as organisms have developed resistance against them. Overconsumption is not just limited to human health care, but also occurs in other areas such as aquaculture, livestock, and veterinary applications for the purpose of improving feed and meat products. Due to their harmful effects on non-target species, the trace level of antibiotics in the aquatic ecosystem presents a significant problem. Since the introduction of antibiotics into the environment is more than their removal, they have been given the status of persistent pollutants. The buildup of antibiotics in the environment threatens aquatic life and may lead to bacterial strains developing resistance. As newer organisms are becoming resistant, there exists a shortage of antibiotics to treat infections. This has presented a very critical problem for the health-care community. Another rising concern is that the development of newer drug molecules as antibiotics is minimal. This review article critically explains the cause and nature of the pollution and the effects of this emerging trend. Also, in the latter sections, why we need newer antibiotics is questioned and discussed.

Cost-utility analysis of the universal pneumococcal vaccination programme for older adults in Norway

The aim of this study was to establish whether the universal pneumococcal vaccination for older adults in Norway is likely to be cost-effective from the perspective of the health care provider. A decision tree model developed by the Public Health Agency of Sweden was adapted to the Norwegian setting. Two cohorts, consisting of 65-year-olds and 75-year-olds grouped into vaccinated and unvaccinated, were followed over a 5-year time horizon. In the base case, the 23-valent polysaccharide vaccine (PPV23) was used while the 13-valent pneumococcal conjugate vaccine (PCV13) was included in scenario analyses only. The costs and health benefits (measured in quality adjusted life years (QALY) gained) were compared in the two cohorts between the vaccinated and unvaccinated groups. The impact of indirect effects of the vaccine, such as herd immunity and serotype replacement, were not investigated. The relative importance of change in price was assessed by performing one-way sensitivity analyses. Under base-case assumptions, the programme for the 75-year-old cohort is expected to be dominant (cost-effective) from the health care perspective at the current maximal pharmacy retail price and at 75% vaccination coverage. In comparison, for the 65-year-old cohort the cost per QALY gained is approximately NOK 601,784 (EUR 61,281) under the base-case assumptions. A reduction in the cost of the vaccine to one quarter of its current level also brings the cost per QALY gained within the acceptable ranges in a Norwegian context for both the 65- and 75-year-old cohorts. There is no exact cost-effectiveness threshold in Norway. However, introducing a vaccination programme against pneumococcal disease for 65-year-olds in Norway is likely to fall within the acceptable range while for the 75-year-old cohort the universal programme appears to be dominant (cost-effective).

Diagnosis of Streptococcus pneumoniae infection using circulating antibody secreting cells

BACKGROUND

Streptococcus pneumoniae infections cause morbidity and mortality worldwide. A rapid, simple diagnostic method could reduce the time needed to introduce definitive therapy potentially improving patient outcomes.

METHODS

We introduce two new methods for diagnosing S. pneumoniae infections by measuring the presence of newly activated, pathogen-specific, circulating Antibody Secreting Cells (ASC). First, ASC were detected by ELISpot assays that measure cells secreting antibodies specific for signature antigens. Second, the antibodies secreted by isolated ASC were collected in vitro in a novel matrix, MENSA (media enriched with newly synthesized antibodies) and antibodies against S. pneumoniae antigens were measured using Luminex immunoassays. Each assay was evaluated using blood from S. pneumoniae and non-S. pneumoniae-infected adult patients.

RESULTS

We enrolled 23 patients with culture-confirmed S. pneumoniae infections and 24 controls consisting of 12 non-S. pneumoniae infections, 10 healthy donors and two colonized with S. pneumoniae. By ELISpot assays, twenty-one of 23 infected patients were positive, and all 24 controls were negative. Using MENSA samples, four of five S. pneumoniae-infected patients were positive by Luminex immunoassays while all five non-S. pneumoniae-infected patients were negative.

CONCLUSION

Specific antibodies produced by activated ASC may provide a simple diagnostic for ongoing S. pneumoniae infections. This method has the potential to diagnose acute bacterial infections.

Genotypic and phenotypic characteristics of Streptococcus pneumoniae from community-acquired pneumonia patients and healthy asymptomatic participants in Sichuan province, China

Background

Streptococcus pneumoniae (S. pneumoniae) is the common cause of community-acquired pneumonia (CAP) and is also found in the upper respiratory tract of healthy people. Hence, the study aimed to compare the serotypes, virulence/pili genes, and antibiotic susceptibility of S. pneumoniae from healthy asymptomatic participants and CAP patients.

Methods

Streptococcus pneumoniae were retrospectively collected from health asymptomatic participants and CAP patients in Sichuan, China. The serotypes were tested by multiplex polymerase chain reaction (PCR) or Quellung reaction. Antibiotic susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S. pneumoniae was analyzed by multilocus sequence typing (MLST). Additionally, the presence of virulence/pili genes were detected using PCR.

Results

A total of 83 pneumococcal isolates were collected in the current study. Of these, 52 and 31 isolates were from healthy asymptomatic participants and CAP patients, respectively. Most of S. pneumoniae were resistant to erythromycin (ERY), clindamycin (CLI), tetracycline (TET) and trimethoprim-sulfamethoxazole (SXT). 90.4% isolates were classified as multidrug resistant (MDR). The predominant serotypes were 3, 19F and 19A in the CAP carriers, whereas 3, 6 and 19F were the main serotypes among the asymptomatic carriers. The overall coverage rates of pneumococcal conjugate vaccine (PCV) 10 and PCV13 serotypes were 34.9% and 66.3%, respectively. The predominant sequence types (STs) were ST271, ST320, and ST3397. There were significant differences in some resistance and virulence characteristics between CAP patients and asymptomatic carriers. Additionally, clonal complex (CC) 271 strains had higher percentage in resistance to cefuroxime (CXM) and cefotaxime (CEF), meropenem (MER) and cefepime (CFP), which mainly carried the rlrA and sipA genes.

Conclusions

High coverage rate of PCV13 and high prevalence of MDR indicated the necessity to expand immunization with PCV13 and rationally use the antibiotics in Sichuan, China. Importantly, long-term surveillance should be conducted to assess effectiveness brought by vaccines. Our findings may supply new guidance for developing new pneumococcal vaccines.

Efficacy of Omadacycline Versus Moxifloxacin in the Treatment of Community-Acquired Bacterial Pneumonia by Disease Severity: Results From the OPTIC Study

Background

Severity/mortality risk scores and disease characteristics may assist in deciding whether patients with community-acquired bacterial pneumonia (CABP) require outpatient treatment or hospitalization. The phase 3 OPTIC (Omadacycline for Pneumonia Treatment In the Community) study enrolled patients with Pneumonia Outcomes Research Team (PORT) risk class II–IV. Omadacycline demonstrated noninferiority to moxifloxacin in adults with CABP, at early clinical response (ECR) and posttreatment evaluation (PTE). We assessed efficacy of omadacycline versus moxifloxacin in these patients based on disease severity.

Methods

Patients were randomized 1:1 to receive intravenous (IV) omadacycline (100 mg every 12 hours for 2 doses followed by 100 mg daily [q24h], with optional transition to omadacycline 300 mg orally q24h after 3 days of IV treatment) or moxifloxacin IV 400 mg q24h (with optional transition to 400 mg orally q24h after 3 days of IV treatment). Total treatment duration was 7–14 days. We compared rates of early clinical success (72–120 hours after first dose) and investigator-assessed clinical success at PTE (5–10 days after last dose) in subgroups based (1) on severity/mortality risk scores (PORT, CURB-65, systemic inflammatory response syndrome, quick Sequential [Sepsis-related] Organ Failure Assessment, modified ATS, SMART-COP) and (2) on presence of baseline radiographic characteristics, chronic obstructive pulmonary disease (COPD)/asthma, or bacteremia.

Results

Altogether, 774 patients (omadacycline, n = 386; moxifloxacin, n = 388) were randomized. Clinical success rates (ECR/PTE) were similar between treatment groups (across all subgroups). Efficacy across treatment groups was similar in patients with baseline radiographic characteristics or COPD/asthma, but moxifloxacin had higher clinical success rates in patients with bacteremia.

Conclusions

Efficacy of omadacycline was similar to that of moxifloxacin, regardless of disease severity/mortality risk and disease characteristics.

Bacterial Membrane Vesicles in Pneumonia: From Mediators of Virulence to Innovative Vaccine Candidates

Pneumonia due to respiratory infection with most prominently bacteria, but also viruses, fungi, or parasites is the leading cause of death worldwide among all infectious disease in both adults and infants. The introduction of modern antibiotic treatment regimens and vaccine strategies has helped to lower the burden of bacterial pneumonia, yet due to the unavailability or refusal of vaccines and antimicrobials in parts of the global population, the rise of multidrug resistant pathogens, and high fatality rates even in patients treated with appropriate antibiotics pneumonia remains a global threat. As such, a better understanding of pathogen virulence on the one, and the development of innovative vaccine strategies on the other hand are once again in dire need in the perennial fight of men against microbes. Recent data show that the secretome of bacteria consists not only of soluble mediators of virulence but also to a significant proportion of extracellular vesicles—lipid bilayer-delimited particles that form integral mediators of intercellular communication. Extracellular vesicles are released from cells of all kinds of organisms, including both Gram-negative and Gram-positive bacteria in which case they are commonly termed outer membrane vesicles (OMVs) and membrane vesicles (MVs), respectively. (O)MVs can trigger inflammatory responses to specific pathogens including S. pneumonia, P. aeruginosa, and L. pneumophila and as such, mediate bacterial virulence in pneumonia by challenging the host respiratory epithelium and cellular and humoral immunity. In parallel, however, (O)MVs have recently emerged as auspicious vaccine candidates due to their natural antigenicity and favorable biochemical properties. First studies highlight the efficacy of such vaccines in animal models exposed to (O)MVs from B. pertussis, S. pneumoniae, A. baumannii, and K. pneumoniae. An advanced and balanced recognition of both the detrimental effects of (O)MVs and their immunogenic potential could pave the way to novel treatment strategies in pneumonia and effective preventive approaches.

Community-acquired pneumonia: aetiology, antibiotic resistance and prospects of phage therapy

Bacteria are the most common aetiological agents of community-acquired pneumonia (CAP) and use a variety of mechanisms to evade the host immune system. With the emerging antibiotic resistance, CAP-causing bacteria have now become resistant to most antibiotics. Consequently, significant morbimortality is attributed to CAP despite their varying rates depending on the clinical setting in which the patients being treated. Therefore, there is a pressing need for a safe and effective alternative or supplement to conventional antibiotics. Bacteriophages could be a ray of hope as they are specific in killing their host bacteria. Several bacteriophages had been identified that can efficiently parasitize bacteria related to CAP infection and have shown a promising protective effect. Thus, bacteriophages have shown immense possibilities against CAP inflicted by multidrug-resistant bacteria. This review provides an overview of common antibiotic-resistant CAP bacteria with a comprehensive summarization of the promising bacteriophage candidates for prospective phage therapy.

Epidemiology, vaccine effectiveness, and risk factors for mortality for pneumococcal disease among hospitalised adults in Singapore: a case-control study

BACKGROUND

Streptococcus pneumoniae infections can lead to severe morbidity and mortality, especially in patients with invasive pneumococcal disease (IPD). This study evaluated factors associated with pneumococcal disease, pneumococcal vaccine effectiveness, and risk factors for all-cause mortality in hospitalised adults with pneumococcal disease in Singapore.

METHODS

Retrospective case-control study of patients tested for pneumococcal disease with streptococcal urinary antigen testing and at least one sterile site culture, during their admission to a tertiary hospital in Singapore from 2015 to 2017. Patients were defined as cases of IPD or non-IPD, or as controls, based on laboratory results and clinical diagnoses. Multivariable models were constructed to determine factors associated with IPD/non-IPD, and risk factors for mortality from pneumococcal disease. Vaccine effectiveness against IPD/non-IPD was estimated using a variation of the test-negative design.

RESULTS

We identified 496 pneumococcal disease cases, of whom 92 (18.5%) had IPD. The mean age of cases was 69.1 ± 15.4 years, and 65.5% were male. Compared with controls (N = 9181), IPD patients were younger (mean age 61.5 ± 16.3 years, vs 72.2 ± 16.1 years in controls; p < 0.001) and with less co-morbidities [median Charlson's score 1 (IQR 0-4), vs 3 (1-5) in controls; p < 0.001]. IPD patients also had the highest proportions with intensive care unit (ICU) admission (20.7%), inpatient mortality (26.1%) and longest median length of stay [9 (IQR 8-17) days]. On multivariable analysis, IPD was negatively associated with prior pneumococcal vaccination (adjusted relative risk ratio = 0.20, 95%CI 0.06-0.69; p = 0.011). Risk factors for mortality among pneumococcal disease patients were ICU admission, diagnosis of IPD, age ≥ 85 years and Charlson's score > 3.

CONCLUSION

Patients with pneumococcal disease (especially IPD) were younger and had less co-morbidities than controls, but had higher risk of severe clinical outcomes and mortality. Pneumococcal vaccination effectiveness against IPD was estimated to be about 80%, and should be encouraged among high-risk patients.

Signal Detection of Adverse Events Following Pneumococcal Vaccines from the Korea Adverse Event Reporting System Database, 2005-2016

PURPOSE

We aimed to analyze the surveillance reports of adverse events (AEs) due to different types of pneumococcal vaccines, in addition to detecting and validating signals of pneumococcal vaccines by comparing AEs with labels.

MATERIALS AND METHODS

We analyzed the percentages of AEs according to vaccine type [pneumococcal polysaccharide vaccines (PPSVs) and pneumococcal conjugate vaccines (PCVs)] in children and adults using data from the Korea Adverse Event Reporting System (KAERS) database from 2005 to 2016. A signal was defined as an AE that met all three indices of data mining: proportional reporting ratio (PRR), reporting odds ratio (ROR), and information component (IC). We validated the detected signals by calculating sensitivity, specificity, as well as positive and negative predictive values of the signals against label information.

RESULTS

Of the 39933 AE reports on vaccination, 5718 (7.0%) were related to pneumococcal vaccine. The most frequent AE after vaccination with PPSV was fever (23.9%) in children and injection-site reaction in adults. The most frequent AE after vaccination with PCV in children was pharyngitis (26.2%). In total, 13 AEs met all three indices for signal detection. Among these, hypotension, apathy, sepsis, and increased serum glutamic oxaloacetic transaminase level were not listed on vaccine labels. In validation analysis, PRR and ROR performed slightly better than IC for adults who were vaccinated with PPSVs.

CONCLUSION

Overall, 13 new signals of PPSVs, including four signals not listed on the labels, were detected. Further research based on additional AE reports is required to confirm the validity of these signals for children.

Inhibition of the PI3K/AKT Signaling Pathway or Overexpression of Beclin1 Blocks Reinfection of Streptococcus pneumoniae After Infection of Influenza A Virus in Severe Community-Acquired Pneumonia

Streptococcus pneumoniae (S. pneumoniae) and viruses are considered as primary risks of community-acquired pneumonia (CAP), and the effects of co-infection bacterial and virus in the prognosis of patients with severe CAP (SCAP) are poorly described. Therefore, this study is conducted to investigate the regulation of Beclin1-PI3K/AKT axis in reinfection of S. pneumoniae after influenza A virus in mice model of bronchoalveolar lavage fluid (BALF). Samples of sputum and BALF were collected from patients with SCAP for etiological detection. The expression of each gene was determined by RT-qPCR and western blot analysis. Influenza A/PR/8/34 and S. pneumoniae were used to establish the mice model of reinfection pneumonia. The virus quantity, expression levels of inflammatory factors, bacterial load, and myeloperoxidase (MPO) activity were tested. HE staining was applied to observe histopathology of lung tissue. The expression of Beclin1 was downregulated and the PI3K/AKT pathway was activated in viral pneumonia. In vivo experiment, the reinfection of S. pneumoniae following influenza A virus infection increased the number of S. pneumoniae population, the activity of MPO, and the expression of TNF-α, IL-6, and IFN-γ in BALF of mice. In contrast, inhibition of the PI3K/AKT pathway or overexpression of Beclin1 reduced the number of S. pneumoniae population, the activity of MPO, and the expression of TNF-α, IL-6, and IFN-γ in BALF of mice reinfected with S. pneumoniae after influenza A virus infection. Collectively, our study demonstrates that inhibition of the PI3K/AKT signaling pathway or overexpressed Beclin1 alleviates reinfection of S. pneumoniae after influenza A virus infection in SCAP.

Allergic inflammation alters the lung microbiome and hinders synergistic co-infection with H1N1 influenza virus and Streptococcus pneumoniae in C57BL/6 mice

Asthma is a chronic airways condition that can be exacerbated during respiratory infections. Our previous work, together with epidemiologic findings that asthmatics were less likely to suffer from severe influenza during the 2009 pandemic, suggest that additional complications of influenza such as increased susceptibility to bacterial superinfection, may be mitigated in allergic hosts. To test this hypothesis, we developed a murine model of 'triple-disease' in which mice rendered allergic to Aspergillus fumigatus were co-infected with influenza A virus and Streptococcus pneumoniae seven days apart. Significant alterations to known synergistic effects of co-infection were noted in the allergic mice including reduced morbidity and mortality, bacterial burden, maintenance of alveolar macrophages, and reduced lung inflammation and damage. The lung microbiome of allergic mice differed from that of non-allergic mice during co-infection and antibiotic-induced perturbation to the microbiome rendered allergic animals susceptible to severe morbidity. Our data suggest that responses to co-infection in allergic hosts likely depends on the immune and microbiome states and that antibiotics should be used with caution in individuals with underlying chronic lung disease.

Streptococcus pneumoniae as a Cause of Community-Acquired Pneumonia in Indian Adolescents and Adults: A Systematic Review and Meta-Analysis

BACKGROUND

Streptococcus pneumoniae is one of the primary cause of community-acquired pneumonia (CAP) worldwide. However, scant data are available on the prevalence of etiological organisms for CAP in adolescent and adult Indian population.

OBJECTIVE

We performed a systematic review and meta-analysis to determine the contribution of S. pneumoniae in the causation of CAP in Indian patients aged 12 years or above.

METHODOLOGY

We performed a systematic search of both indexed and non-indexed publications using PubMed, databases of National Institute of Science Communication and Information Resources (NISCAIR), Annotated Bibliography of Indian Medicine (ABIM), Google Scholar, and hand search including cross-references using key terms 'community acquired pneumonia AND India'. All studies, published between January 1990 and January 2017, that evaluated Indian patients aged above 12 years with a confirmed diagnosis of CAP were eligible for inclusion. Our search retrieved a total of 182 studies, of which only 17 and 12 qualified for inclusion in the systematic review of all etiological organisms, and meta-analysis of S. pneumonia, respectively.

RESULTS

A total of 1435 patients met the inclusion criteria. The pooled proportion of patients with S. pneumoniae infection was 19% (95% confidence interval [CI]: 12%-26%; I2 = 94.5% where I2 represents heterogeneity, P < .01). Other major etiological agents are Mycoplasma pneumoniae (15.5% [1.1%-35.5%]), Klebsiella pneumoniae (10.5% [1.6%-24.0%]), and Legionella pneumophila (7.3% [2.5%-23.8%]).

CONCLUSIONS

Analysis found approximately a one-fifth proportion of adult Indian patients of CAP with S. pneumoniae infection, suggesting it as a leading organism for causing CAP compared with other etiological organisms.

Distribution of 13-Valent pneumococcal conjugate vaccine serotype streptococcus pneumoniae in adults 50 Years and Older presenting with community-acquired pneumonia in Israel

BACKGROUND

Community acquired pneumonia (CAP) is a major cause of morbidity and mortality worldwide, and is a leading cause of hospitalization in previously healthy individuals without predisposing risk factors or comorbidities. In this study we determined PCV13 serotype distribution in adults aged ≥50 years with radiographically confirmed CAP in Israel.

METHODS

Subjects aged ≥50 years were enrolled from one of three hospitals (Emek Medical Center, Meir Medical Center and Sheba Medical Center) from March 2014 to July 2015. Information was collected on subject demographics, comorbidities, risk factors, and pneumococcal vaccine immunization status. Subjects presented with suspected CAP supported by radiographic evidence, and provided a urine sample and informed consent. Subjects without radiographic confirmation of CAP or who received PPSV23 within 30 days of study enrollment were excluded from the final analysis. Serotype distribution was performed using the urinary antigen detection (UAD) assay and/or microbiological culture.

RESULTS

Overall, 498 subjects with radiographically confirmed CAP were enrolled in the study. Eighty subjects (16.1%) were positive for any S. pneumoniae serotype by ≥1 assay, and 38 (7.6%) were positive for PCV13 serotypes via the UAD. The overall 30-day mortality rate was 1.2%, though S. pneumoniae was not isolated from any case leading to death.

CONCLUSION

Despite six years of high pneumococcal immunization coverage in children in Israel, we have shown that 7.6% of CAP cases among adults in Israel remain related to PCV13 serotypes; and that the burden of PCV13 may be as high as 47% of observed pneumococcal CAP.

Targeting inflammatory monocytes in sepsis-associated encephalopathy and long-term cognitive impairment

Sepsis-associated encephalopathy manifesting as delirium is a common problem in critical care medicine. In this study, patients that had delirium due to sepsis had significant cognitive impairments at 12-18 months after hospital discharge when compared with controls and Cambridge Neuropsychological Automated Test Battery-standardized scores in spatial recognition memory, pattern recognition memory, and delayed-matching-to-sample tests but not other cognitive functions. A mouse model of S. pneumoniae pneumonia-induced sepsis, which modeled numerous aspects of the human sepsis-associated multiorgan dysfunction, including encephalopathy, also revealed similar deficits in spatial memory but not new task learning. Both humans and mice had large increases in chemokines for myeloid cell recruitment. Intravital imaging of the brains of septic mice revealed increased neutrophil and CCR2+ inflammatory monocyte recruitment (the latter being far more robust), accompanied by subtle microglial activation. Prevention of CCR2+ inflammatory monocyte recruitment, but not neutrophil recruitment, reduced microglial activation and other signs of neuroinflammation and prevented all signs of cognitive impairment after infection. Therefore, therapeutically targeting CCR2+ inflammatory monocytes at the time of sepsis may provide a novel neuroprotective clinical intervention to prevent the development of persistent cognitive impairments.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

We searched for published or unpublished randomized controlled trials.

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Streptococcus pneumoniae-associated pneumonia complicated by purulent pericarditis: case series

Objective:

In the antibiotic era, purulent pericarditis is a rare entity. However, there are still reports of cases of the disease, which is associated with high mortality, and most such cases are attributed to delayed diagnosis. Approximately 40-50% of all cases of purulent pericarditis are caused by Gram-positive bacteria, Streptococcus pneumoniae in particular.

Methods:

We report four cases of pneumococcal pneumonia complicated by pericarditis, with different clinical features and levels of severity.

Results:

In three of the four cases, the main complication was cardiac tamponade. Microbiological screening (urinary antigen testing and pleural fluid culture) confirmed the diagnosis of severe pneumococcal pneumonia complicated by purulent pericarditis.

Conclusions:

In cases of pneumococcal pneumonia complicated by pericarditis, early diagnosis is of paramount importance to avoid severe hemodynamic compromise. The complications of acute pericarditis appear early in the clinical course of the infection. The most serious complications are cardiac tamponade and its consequences. Antibiotic therapy combined with pericardiocentesis drastically reduces the mortality associated with purulent pericarditis.

A Year of Infection in the Intensive Care Unit: Prospective Whole Genome Sequencing of Bacterial Clinical Isolates Reveals Cryptic Transmissions and Novel Microbiota

Bacterial whole genome sequencing holds promise as a disruptive technology in clinical microbiology, but it has not yet been applied systematically or comprehensively within a clinical context. Here, over the course of one year, we performed prospective collection and whole genome sequencing of nearly all bacterial isolates obtained from a tertiary care hospital's intensive care units (ICUs). This unbiased collection of 1,229 bacterial genomes from 391 patients enables detailed exploration of several features of clinical pathogens. A sizable fraction of isolates identified as clinically relevant corresponded to previously undescribed species: 12% of isolates assigned a species-level classification by conventional methods actually qualified as distinct, novel genomospecies on the basis of genomic similarity. Pan-genome analysis of the most frequently encountered pathogens in the collection revealed substantial variation in pan-genome size (1,420 to 20,432 genes) and the rate of gene discovery (1 to 152 genes per isolate sequenced). Surprisingly, although potential nosocomial transmission of actively surveilled pathogens was rare, 8.7% of isolates belonged to genomically related clonal lineages that were present among multiple patients, usually with overlapping hospital admissions, and were associated with clinically significant infection in 62% of patients from which they were recovered. Multi-patient clonal lineages were particularly evident in the neonatal care unit, where seven separate Staphylococcus epidermidis clonal lineages were identified, including one lineage associated with bacteremia in 5/9 neonates. Our study highlights key differences in the information made available by conventional microbiological practices versus whole genome sequencing, and motivates the further integration of microbial genome sequencing into routine clinical care.

Low C-reactive protein values at admission predict mortality in patients with severe community-acquired pneumonia caused by Streptococcus pneumoniae that require intensive care management

Purpose

To identify risk factors associated with mortality in patients with severe community-acquired pneumonia (CAP) caused by S. pneumoniae who require intensive care unit (ICU) management, and to assess the prognostic values of these risk factors at the time of admission.

Methods

Retrospective analysis of all consecutive patients with CAP caused by S. pneumoniae who were admitted to the 32-bed medico-surgical ICU of a community and referral university hospital between 2002 and 2011. Univariate and multivariate analyses were performed on variables available at admission.

Results

Among the 77 adult patients with severe CAP caused by S. pneumoniae who required ICU management, 12 patients died (observed mortality rate 15.6 %). Univariate analysis indicated that septic shock and low C-reactive protein (CRP) values at admission were associated with an increased risk of death. In a multivariate model, after adjustment for age and gender, septic shock [odds ratio (OR), confidence interval 95 %; 4.96, 1.11–22.25; p = 0.036], and CRP (OR 0.99, 0.98–0.99 p = 0.034) remained significantly associated with death. Finally, we assessed the discriminative ability of CRP to predict mortality by computing its receiver operating characteristic curve. The CRP value cut-off for the best sensitivity and specificity was 169.5 mg/L to predict hospital mortality with an area under the curve of 0.72 (0.55–0.89).

Conclusions

The mortality of patients with S. pneumoniae CAP requiring ICU management was much lower than predicted by severity scores. The presence of septic shock and a CRP value at admission <169.5 mg/L predicted a fatal outcome.

TLR4 mediates pneumolysin-induced ATF3 expression through the JNK/p38 pathway in Streptococcus pneumoniae-infected RAW 264.7 cells

Activating transcription factor-3 (ATF3) acts as a negative regulator of cytokine production during Gram-negative bacterial infection. A recent study reported that ATF3 provides protection from Streptococcus pneumoniae infection by activating cytokines. However, the mechanism by which S. pneumoniae induces ATF3 after infection is still unknown. In this study, we show that ATF3 was upregulated via Toll-like receptor (TLR) pathways in response to S. pneumoniae infection in vitro. Induction was mediated by TLR4 and TLR2, which are in the TLR family. The expression of ATF3 was induced by pneumolysin (PLY), a potent pneumococcal virulence factor, via the TLR4 pathway. Furthermore, ATF3 induction is mediated by p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Thus, this study reveals a potential role of PLY in modulating ATF3 expression, which is required for the regulation of immune responses against pneumococcal infection in macrophages.

Diagnostic Accuracy of Chest x-Ray and Ultrasonography in Detection of Community Acquired Pneumonia; a Brief Report

INTRODUCTION

Chest x-ray (CXR) is the simplest diagnostic tool of Community Acquired Pneumonia (CAP), but it has some limitation. Therefore, the aim of this study is comparing the diagnostic accuracy of CXR and chest ultrasonography (CUS) in detection of CAP.

METHODS

In the present study, a consecutive sample of suspected patients with CAP was underwent CUS, CXR, and chest computed tomography (CT) scan. Diagnostic accuracy of CUS and CXR was assessed by calculating the sensitivity, specificity, predictive values, and likelihood ratios using SPSS 20 statistical software.

RESULTS

30 patients with CAP were enrolled (93.3% male with mean age of 63.8 ± 18.3 years). Sensitivity of CUS and CXR in detection of CAP were 100.0% (95% Cl: 85.4-100.0) and 93.1% (95% Cl: 75.8-98.8), respectively. Specificity of CXR was 0.0 (95% Cl: 0.0-94.5), while the CUS specificity was not calculable.

CONCLUSION

Findings of the present study demonstrated on the higher diagnostic accuracy of CUS versus CXR in detection of pneumonia.

Epidemiology of pneumococcal disease in a national cohort of older adults

Introduction

Streptococcus pneumoniae is a major cause of morbidity and mortality. We sought to describe the epidemiology of non-invasive and invasive pneumococcal disease in a national Veterans Affairs population within the United States.

Methods

We conducted a retrospective study in older patients (aged ≥50 years) with positive pneumococcal cultures from any site between 2002 and 2011. We described outpatient and inpatient pneumococcal disease incidence per 100,000 clinic visits/hospitalizations. Repeat cultures within a 30-day period were considered to represent the same episode. To describe the epidemiology of serious pneumococcal infections (bacteremia, meningitis, pneumonia), we assessed demographics, clinical characteristics, and risk factors for S. pneumoniae. Pneumonia was defined as a positive respiratory culture with a pneumonia diagnosis code. Bacteremia and meningitis were identified from positive cultures. Generalized linear mixed models were used to quantify changes over time.

Results

Over the study period, we identified 45,983 unique episodes of pneumococcal disease (defined by positive cultures). Incidence decreased significantly by 3.5% per year in outpatients and increased non-significantly by 0.2% per year in inpatients. In 2011, the outpatient and inpatient incidence was 2.6 and 328.1 infections per 100,000 clinic visits/hospitalizations, respectively. Among inpatients with serious infections, chronic disease risk factors for pneumococcal disease increased significantly each year, including respiratory disease (1.9% annually), diabetes (1.3%), and renal failure (1.0%). Overall, 30.2% of inpatients with serious infections had a pneumococcal immunization in the previous 5 years. Invasive disease (37.4% versus 34.9%, P = 0.004) and mortality (14.0% versus 12.7%, P = 0.045) were higher in non-vaccinated patients compared to vaccinated patients.

Conclusions

In our national study of older adults, the baseline health status of those with serious pneumococcal infections worsened over the study period. As the population ages and the chronic disease epidemic grows, the burden of pneumococcal disease is likely to increase thus highlighting the importance of pneumococcal vaccination.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0025-y) contains supplementary material, which is available to authorized users.

Evaluation of yield of currently available diagnostics by sample type to optimize detection of respiratory pathogens in patients with a community-acquired pneumonia

BACKGROUND

For the detection of respiratory pathogens, the sampling strategy may influence the diagnostic yield. Ideally, samples from the lower respiratory tract are collected, but they are difficult to obtain.

OBJECTIVES

In this study, we compared the diagnostic yield in sputum and oropharyngeal samples (OPS) for the detection of respiratory pathogens in patients with community-acquired pneumonia (CAP), with the objective to optimize our diagnostic testing algorithm.

METHODS

Matched sputum samples, OPS, blood cultures, serum, and urine samples were taken from patients (>18 years) with CAP and tested for the presence of possible respiratory pathogens using bacterial cultures, PCR for 17 viruses and five bacteria and urinary antigen testing.

RESULTS

When using only conventional methods, that is, blood cultures, sputum culture, urinary antigen tests, a pathogen was detected in 49·6% of patients (n = 57). Adding molecular detection assays increased the yield to 80%. A pathogen was detected in 77 of the 115 patients in OPS or sputum samples by PCR. The sensitivity of the OPS was lower than that of the sputum samples (57% versus 74%). In particular, bacterial pathogens were more often detected in sputum samples. The sensitivity of OPS for the detection of most viruses was higher than in sputum samples (72% versus 66%), except for human rhinovirus and respiratory syncytial virus.

CONCLUSION

Addition of PCR on both OPS and sputum samples significantly increased the diagnostic yield. For molecular detection of bacterial pathogens, a sputum sample is imperative, but for detection of most viral pathogens, an OPS is sufficient.

Randomized, double-blind, multicenter phase 2 study comparing the efficacy and safety of oral solithromycin (CEM-101) to those of oral levofloxacin in the treatment of patients with community-acquired bacterial pneumonia

Solithromycin, a new macrolide, and the first fluoroketolide in clinical development, with activity against macrolide-resistant bacteria, was tested in 132 patients with moderate to moderately severe community-acquired bacterial pneumonia (CABP) in a multicenter, double-blind, randomized phase 2 study. Patients were enrolled and randomized (1:1) to either 800 mg solithromycin orally (PO) on day 1, followed by 400 mg PO daily on days 2 to 5, or 750 mg levofloxacin PO daily on days 1 to 5. Efficacy outcome rates of clinical success at the test-of-cure visit 4 to 11 days after the last dose of study drug were comparable in the intent-to-treat (ITT) (84.6% for solithromycin versus 86.6% for levofloxacin) and microbiological-intent-to-treat (micro-ITT) (77.8% for solithromycin versus 71.4% for levofloxacin) populations. Early response success rates at day 3, defined as improvement in at least two cardinal symptoms of pneumonia, were also comparable (72.3% for solithromycin versus 71.6% for levofloxacin). More patients treated with levofloxacin than with solithromycin experienced treatment-emergent adverse events (TEAEs) during the study (45.6% versus 29.7%). The majority of TEAEs were mild or moderate gastrointestinal symptoms and included nausea (1.6% for solithromycin; 10.3% for levofloxacin), diarrhea (7.8% for solithromycin; 5.9% for levofloxacin), and vomiting (0% for solithromycin; 4.4% for levofloxacin). Six patients, all of whom received levofloxacin, discontinued the study drug due to an adverse event. Solithromycin demonstrated comparable efficacy and favorable safety relative to levofloxacin. These findings support a phase 3 study of solithromycin for the treatment of CABP. (This study has been registered at ClinicalTrials.gov under registration no. NCT01168713.).

Cost-effectiveness of new adult pneumococcal vaccination strategies in Italy

Community-acquired pneumonia (CAP) and invasive pneumococcal disease (IPD) are very relevant pathologies among elderly people (≥ 65 y old), with a consequent high disease burden. Immunization with the 23-valent pneumococcal polysaccharide vaccine (PPV23) has been differently implemented in the Italian regions in the past years, reaching overall low coverage rates even in those with medical indications. In 2010, the 13-valent pneumococcal conjugate vaccine (PCV13) became available and recommended in the universal Italian infant immunization program. Since October 2012, indications for use of PCV13 were extended to subjects ≥ 50 y to prevent invasive pneumococcal diseases. The Italian decision makers should now revise regional indications for the prevention of pneumococcal diseases in the elderly. Pharmaco-economic analyses represent a useful tool to value the feasibility of new immunization programs and their sustainability. Therefore, an ad hoc population model was developed in order to value the clinical and economic impact of an adult pneumococcal vaccination program in Italy.   Particularly, different immunization scenarios were modeled: vaccination of 65 y-olds (1 cohort strategy), simultaneous vaccination of people aged 65 and 70 y (double cohort strategy) and, lastly, immunization of people aged 65, 70 and 75 y (triple cohort strategy), thus leading to the vaccination of 5, 10 and 15 cohorts during the 5 y of the program. In addition, the administration of a PPV23 dose one year after PCV13 was evaluated, in order to verify the economic impact of the supplemental serotype coverage in elderly people. The mathematical model valued the clinical impact of PCV13 vaccination on the number of bacteraemic pneumococcal pneumonia (BPP) and pneumococcal meningitis (PM) cases, and related hospitalizations and deaths. Although PCV13 is not yet formally indicated for the prevention of pneumococcal CAP by the European Medicine Agency (differently from FDA, whose indications include all pneumococcal diseases in subjects ≥ 50 y), the model calculated also the possible impact of vaccination on CAP cases (non-bacteraemic), considering the rate of this disease due to S. pneumoniae. The results of the analysis show that, in Italy, an age-based PCV13 vaccination program in elderly people is cost-effective from the payer perspective, with costs per QALY ranging from 17,000 to 22,000 Euro, according to the adopted vaccination strategy. The subsequent PPV23 offer results in an increment of costs per QALY (from 21,000 to 28,000 Euro, according to the vaccination strategy adopted). Pneumococcal vaccination using the conjugate vaccine turned out to be already favorable in the second year of implementation, with incremental costs per QALY comparable to those of other already adopted prevention activities in Italy (for instance, universal HPV vaccination of 12 y-old girls), with further benefits obtained when extending the study period beyond the 5-y horizon of our analysis.

Cethromycin versus clarithromycin for community-acquired pneumonia: comparative efficacy and safety outcomes from two double-blinded, randomized, parallel-group, multicenter, multinational noninferiority studies

Community-acquired pneumonia (CAP) continues to be a major health challenge in the United States and globally. Factors such as overprescribing of antibiotics and noncompliance with dosing regimens have added to the growing antibacterial resistance problem. In addition, several agents available for the treatment of CAP have been associated with serious side effects. Cethromycin is a new ketolide antibiotic that may provide prescribing physicians with an additional agent to supplement a continually limited armamentarium. Two global phase III noninferiority studies (CL05-001 and CL06-001) to evaluate cethromycin safety and efficacy were designed and conducted in patients with mild to moderate CAP. Study CL05-001 demonstrated an 83.1% clinical cure rate in the cethromycin group compared with 81.1% in the clarithromycin group (95% confidence interval [CI], -4.8%, +8.9%) in the intent to treat (ITT) population and a 94.0% cethromycin clinical cure rate compared with a 93.8% clarithromycin cure rate (95% CI, -4.5%, +5.1%) in the per protocol clinical (PPc) population. Study CL06-001 achieved an 82.9% cethromycin clinical cure rate in the ITT population compared with an 88.5% clarithromycin cure rate (95% CI, -11.9%, +0.6%), whereas the clinical cure rate in the PPc population was 91.5% in cethromycin group compared with 95.9% in clarithromycin group (95% CI, -9.1%, +0.3%). Both studies met the primary endpoints for clinical cure rate based on predefined, sliding-scale noninferiority design. Therefore, in comparison with clarithromycin, these two noninferiority studies demonstrated the efficacy and safety of cethromycin, with encouraging findings of efficacy in subjects with Streptococcus pneumoniae bacteremia. No clinically significant adverse events were observed during the studies. Cethromycin may be a potential oral therapy for the outpatient treatment of CAP.

Pneumonia presenting with lower right abdominal pain and migratory polyarthritis

The clinical presentation of community acquired pneumonia (CAP) in adults includes mainly symptoms from the respiratory system, whereas CAP is considered as a main cause of abdominal pain in pediatric patients.

We present the case of a patient, who was admitted to our hospital due to abdominal pain that deteriorated progressively and radiated to the lumbar region. The clinical examination revealed decreased breath sounds at the right lung base after 72 h, while the chest X-ray showed pneumonia of the right lung base. The blood culture isolated Streptococcus pneumoniae, and the patient received penicillin according to the results of the antibiogram. In addition, the patient developed symptoms of migratory arthritis, which resolved after 48 h.

CAP should be included in the differential diagnosis of abdominal pain in adult patients. Furthermore, the hematogenous spread of S. pneumoniae may be associated with the development of migratory arthritis.

Corticotropin-releasing hormone receptor-1 and 2 activity produces divergent resistance against stress-induced pulmonary Streptococcus pneumoniae infection

Utilizing a murine model of S. pneumoniae infection and restraint stress, we determined how corticotropin releasing hormone (CRH-R) receptors impacts disease. CRH-R1 (antalarmin) and CRH-R2 (astressin2B) antagonists were administered intraperitoneally prior to restraint stress followed by pulmonary S. pneumoniae infection. CRH-R1 inhibition is not protective against pneumococcal disease induced by stress. Conversely, CRH-R2 inhibition attenuates stress-induced bacterial growth and significantly prevented severe sepsis. Neutrophillic responses were associated with CRH receptor-specific disease outcome providing a potential cellular target for stress-induced susceptibility to the development of severe pneumococcal disease. CRH receptor-mediated effects on immune responses could prove valuable for novel therapeutics.

Factors affecting the cost effectiveness of antibiotics

In an era of spiraling health care costs and limited resources, policy makers and health care payers are concerned about the cost effectiveness of antibiotics. The aim of this study is to draw on published economic evaluations with a view to identify and illustrate the factors affecting the cost effectiveness of antibiotic treatment of bacterial infections. The findings indicate that the cost effectiveness of antibiotics is influenced by factors relating to the characteristics and the use of antibiotics (i.e., diagnosis, comparative costs and comparative effectiveness, resistance, patient compliance with treatment, and treatment failure) and by external factors (i.e., funding source, clinical pharmacy interventions, and guideline implementation interventions). Physicians need to take into account these factors when prescribing an antibiotic and assess whether a specific antibiotic treatment adds sufficient value to justify its costs.

Factors affecting the cost effectiveness of antibiotics

In an era of spiraling health care costs and limited resources, policy makers and health care payers are concerned about the cost effectiveness of antibiotics. The aim of this study is to draw on published economic evaluations with a view to identify and illustrate the factors affecting the cost effectiveness of antibiotic treatment of bacterial infections. The findings indicate that the cost effectiveness of antibiotics is influenced by factors relating to the characteristics and the use of antibiotics (i.e., diagnosis, comparative costs and comparative effectiveness, resistance, patient compliance with treatment, and treatment failure) and by external factors (i.e., funding source, clinical pharmacy interventions, and guideline implementation interventions). Physicians need to take into account these factors when prescribing an antibiotic and assess whether a specific antibiotic treatment adds sufficient value to justify its costs.

Chronic pulmonary LPS tolerance induces selective immunosuppression while maintaining the neutrophilic response

LPS challenge causes potent activation of innate immunity. Because LPS is ubiquitously present in ambient air, repeated inhalation may lead to activation of the pulmonary immune response. If this activation is unregulated, chronic LPS inhalation would lead to persistent inflammation and organ damage. We hypothesized that the lung uses the mechanism of LPS tolerance to maintain the balance between hypoinflammatory and hyperinflammatory states. We developed a model of chronic pulmonary LPS tolerance induced by pulmonary exposure to 1 microg LPS for 4 consecutive days. Mice were challenged with 10 microg of LPS 24 h later. TNF-alpha protein was significantly decreased in the bronchoalveolar lavage fluid of tolerant versus nontolerant mice, whereas IL-6 levels were significantly increased in the tolerant group. Tolerant mice were also protected from airway hyperresponsiveness. M2 and M3 muscarinic receptor mRNA was significantly decreased in the lungs of tolerant mice, suggesting a mechanism for the decreased airway hyperresponsiveness. CXCL2 was significantly reduced in tolerant mice, but CXCL1 was equivalent between groups. No difference was seen in neutrophil recruitment to the alveolar space. Interestingly, LPS tolerance does not confer cross-tolerance to the Toll-like receptor (TLR) 2 stimulus Pam3Cys. TNF-alpha and IL-6 concentrations were significantly increased in LPS-tolerant mice challenged with Pam3Cys; however, chemokine concentrations were unaffected. Our data show that repeated LPS inhalation results in differential regulation of cytokines but does not inhibit neutrophil recruitment. This unrestricted neutrophil recruitment may represent a mechanism by which individuals may be protected from pulmonary bacterial infection and pneumonia.

Comparison of the automated Phoenix with the Vitek 2 for the identification of Streptococcus pneumoniae

Rapid and accurate identification of Streptococcus pneumoniae is a critical component in the optimal management of infected patients. The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.) was evaluated for identification of S. pneumoniae (n = 311) and was compared to the Vitek 2 (bioMérieux, Marcy l'Etoile, France). Strains with discordant identification between methods were resolved with 16S rRNA gene sequencing as the gold standard. The Phoenix and the Vitek 2 correctly identified 96.8% (n = 301) and 95.2% (n = 296) of S. pneumoniae strains, respectively. Overall, there was no statistically significant difference in the performance of the 2 automated systems for the identification of S. pneumoniae in this study. The Vitek 2 mean time-to-results for all streptococcal identification was 1.5 h faster than that for the Phoenix. We conclude that the automated Phoenix and the Vitek 2 systems are comparable in their ability to identify S. pneumoniae and are preferable to the use of routine biochemical assays, which have delayed time-to-results and are not dependably accurate.

Epidemiology of invasive pneumococcal disease in BC during the introduction of conjugated pneumococcal vaccine

OBJECTIVES

Antimicrobial resistance in Streptococcus pneumoniae has increased in recent decades. We linked two surveillance programs to evaluate trends in incidence, serotype distribution, and antimicrobial resistance in invasive pneumococcal disease (IPD) since the heptavalent pneumococcal conjugate vaccine (PCV7) was introduced in BC in 2003.

METHODS

IPD case reports for BC from 2002-2005 from the BC Centre for Disease Control were linked to serotype and antimicrobial susceptibility results from the National Centre for Streptococcus (NCS).

RESULTS

There was a significant decrease in IPD incidence in children <5 from 54/100,000 in 2002 to 16/100,000 population in 2005 (70% decrease, p < 0.001). The most dramatic decline was in children aged 1 year, where the rate fell from 135/100,000 to 15/100,000 (89% decrease, p for trend <0.001). Overall, 728/1288 (56.5%) reported cases of IPD were referred to NCS. For all matched cases, the proportion of isolates of PCV7 preventable serotypes decreased from 68.9% to 43.8% (p for trend <0.001) between 2002 and 2005. In children <2 years, this proportion decreased from 83.0% (39/47 cases) to 16.7% (1/6 cases) (p = 0.006). The prevalence of non-susceptible isolates was highest for trimethoprim-sulfamethoxazole (15.3%, 111/725 tested), penicillin (9.1%, 66/728), and erythromycin (9.1%, 66/727). 10.3% (75/728) were non-susceptible to > or =2 classes of antimicrobials. Children <15 years of age had the highest proportion of non-susceptible isolates.

DISCUSSION

The incidence of IPD in children has decreased significantly since the introduction of PCV7. Comprehensive serotype and antimicrobial susceptibility can aid in evaluating the impact of immunization programs.

A cost-effectiveness analysis of antimicrobial treatment of community-acquired pneumonia taking into account resistance in Belgium

OBJECTIVE

This article assesses the cost-effectiveness of outpatient antimicrobial treatment of community-acquired pneumonia (CAP) taking into account resistance in Belgium.

RESEARCH DESIGN AND METHODS

Our decision analytic model focused on mild to moderate CAP, but did not consider severe CAP. Treatment pathways reflected empirical treatment initiated in the absence of data on CAP aetiology. First-line treatment consisted of moxifloxacin, co-amoxiclav, cefuroxime or clarithromycin. If first-line treatment was unsuccessful, patients were either hospitalised or second-line treatment with a different antimicrobial was initiated. Clinical failure rates were obtained from the published literature or expert opinion. Costs were calculated using published sources from the third-party payer perspective.

MAIN OUTCOME MEASURES

Effectiveness measures included first-line clinical failure avoided, second-line treatment avoided, hospitalisation avoided and death avoided. Healthcare costs were included, but costs of productivity loss were not considered.

RESULTS

Costs of treating a CAP episode amounted to 144E with moxifloxacin/co-amoxiclav; 222E with co-amoxiclav/clarithromycin; 211E with cefuroxime/moxifloxacin; and 193E with clarithromycin/moxifloxacin. The rate of first-line failure was 5%, 16%, 19% and 18% for these four treatment strategies, respectively. The rate of second-line treatment amounted to 4%, 13%, 16% and 15%, respectively. The hospitalisation rate was 1%, 4%, 4% and 4%, respectively. The death rate was 0.01%, 0.04%, 0.03% and 0.03%, respectively. Sensitivity analyses supported the dominance of moxifloxacin/co-amoxiclav in nearly all scenarios.

CONCLUSIONS

First-line treatment of CAP patients with moxifloxacin followed by co-amoxiclav or hospitalisation if required was more effective and less costly as compared with first-line treatment with co-amoxiclav, cefuroxime or clarithromycin.

Epidemiology of invasive pneumococcal disease in BC during the introduction of conjugated pneumococcal vaccine

OBJECTIVES

Antimicrobial resistance in Streptococcus pneumoniae has increased in recent decades. We linked two surveillance programs to evaluate trends in incidence, serotype distribution, and antimicrobial resistance in invasive pneumococcal disease (IPD) since the heptavalent pneumococcal conjugate vaccine (PCV7) was introduced in BC in 2003.

METHODS

IPD case reports for BC from 2002-2005 from the BC Centre for Disease Control were linked to serotype and antimicrobial susceptibility results from the National Centre for Streptococcus (NCS).

RESULTS

There was a significant decrease in IPD incidence in children <5 from 54/100,000 in 2002 to 16/100,000 population in 2005 (70% decrease, p < 0.001). The most dramatic decline was in children aged 1 year, where the rate fell from 135/100,000 to 15/100,000 (89% decrease, p for trend <0.001). Overall, 728/1288 (56.5%) reported cases of IPD were referred to NCS. For all matched cases, the proportion of isolates of PCV7 preventable serotypes decreased from 68.9% to 43.8% (p for trend <0.001) between 2002 and 2005. In children <2 years, this proportion decreased from 83.0% (39/47 cases) to 16.7% (1/6 cases) (p = 0.006). The prevalence of non-susceptible isolates was highest for trimethoprim-sulfamethoxazole (15.3%, 111/725 tested), penicillin (9.1%, 66/728), and erythromycin (9.1%, 66/727). 10.3% (75/728) were non-susceptible to > or =2 classes of antimicrobials. Children <15 years of age had the highest proportion of non-susceptible isolates.

DISCUSSION

The incidence of IPD in children has decreased significantly since the introduction of PCV7. Comprehensive serotype and antimicrobial susceptibility can aid in evaluating the impact of immunization programs.

Cirrhosis-induced defects in innate pulmonary defenses against Streptococcus pneumoniae

Background

The risk of mortality from pneumonia caused by Streptococcus pneumoniae is increased in patients with cirrhosis. However, the specific pneumococcal virulence factors and host immune defects responsible for this finding have not been clearly established. This study used a cirrhotic rat model of pneumococcal pneumonia to identify defect(s) in innate pulmonary defenses in the cirrhotic host and to determine the impact of the pneumococcal toxin pneumolysin on these defenses in the setting of severe cirrhosis.

Results

No cirrhosis-associated defects in mucociliary clearance of pneumococci were found in these studies, but early intrapulmonary killing of the organisms before the arrival of neutrophils was significantly impaired. This defect was exacerbated by pneumolysin production in cirrhotic but not in control rats. Neutrophil-mediated killing of a particularly virulent type 3 pneumococcal strain also was significantly diminished within the lungs of cirrhotic rats with ascites. Levels of lysozyme and complement component C3 were both significantly reduced in bronchoalveolar lavage fluid from cirrhotic rats. Finally, complement deposition was reduced on the surface of pneumococci recovered from the lungs of cirrhotic rats in comparison to organisms recovered from the lungs of control animals.

Conclusion

Increased mortality from pneumococcal pneumonia in this cirrhotic host is related to defects in both early pre-neutrophil- and later neutrophil-mediated pulmonary killing of the organisms. The fact that pneumolysin production impaired pre-neutrophil-mediated pneumococcal killing in cirrhotic but not control rats suggests that pneumolysin may be particularly detrimental to this defense mechanism in the severely cirrhotic host. The decrease in neutrophil-mediated killing of pneumococci within the lungs of the cirrhotic host is related to insufficient deposition of host proteins such as complement C3 on their surfaces. Pneumolysin likely plays a role in complement consumption within the lungs. Our studies, however, were unable to determine whether pneumolysin more negatively impacted this defense mechanism in cirrhotic than in control rats. These findings contribute to our understanding of the defects in innate pulmonary defenses that lead to increased mortality from pneumococcal pneumonia in the severely cirrhotic host. They also suggest that pneumolysin may be a particularly potent pneumococcal virulence factor in the setting of cirrhosis.

Antimicrobial susceptibility and genetic characteristics of Streptococcus pneumoniae isolates indicating possible nosocomial transmission routes in a community hospital in Japan

A clinical study was designed to study Streptococcus pneumoniae isolates recovered from a community hospital in Japan from April 2001 to November 2002. A total of 73 isolates were defined as derived from inpatient, outpatient, and hospital staff groups. The MIC results showed that 20 strains (27.4%) were susceptible to penicillin G, 39 strains (53.4%) had intermediate resistance, and 14 strains (19.2%) had full resistance. Low susceptibility to macrolides was also detected: 32.9%, 32.9%, and 34.2% of all strains were resistant to erythromycin, clarithromycin, and azithromycin, respectively. Thirty strains (41%) were resistant to at least two different kinds of antibiotics. Nineteen disparate serotypes were detected besides two nontypeable strains, and the predominant serotypes were 19F and 23F. Pulsed-field gel electrophoresis (PFGE) pattern A was dominant in the serotype 19F group; this pattern was similar to that of the international clone Taiwan 19F. A total of 10 different patterns were detected in the 23F group and were distinguishable from those of the international clones Spain 23F and Taiwan 23F. Pattern b strains were identified in the same ward, and pattern d strains were found both in patients with nosocomial pneumococcal infections (NPI) and in outpatients. In conclusion, drug-resistant S. pneumoniae was spreading rapidly, especially isolates of the serotype 19F and 23F groups. PFGE data revealed interpatient transmission and suggested that there might be some association between NPI patient strains and outpatient strains.

Amoxicillin is effective against penicillin-resistant Streptococcus pneumoniae strains in a mouse pneumonia model simulating human pharmacokinetics

High-dose oral amoxicillin (3 g/day) is the recommended empirical outpatient treatment of community-acquired pneumonia (CAP) in many European guidelines. To investigate the clinical efficacy of this treatment in CAP caused by Streptococcus pneumoniae strains with MICs of amoxicillin > or =2 microg/ml, we used a lethal bacteremic pneumonia model in leukopenic female Swiss mice with induced renal failure to replicate amoxicillin kinetics in humans given 1 g/8 h orally. Amoxicillin (15 mg/kg of body weight/8 h subcutaneously) was given for 3 days. We used four S. pneumoniae strains with differing amoxicillin susceptibility and tolerance profiles. Rapid bacterial killing occurred with an amoxicillin-susceptible nontolerant strain: after 4 h, blood cultures were negative and lung homogenate counts under the 2 log(10) CFU/ml detection threshold (6.5 log(10) CFU/ml in controls, P < 0.01). With an amoxicillin-intermediate nontolerant strain, significant pulmonary bacterial clearance was observed after 24 h (4.3 versus 7.9 log(10) CFU/ml, P < 0.01), and counts were undetectable 12 h after treatment completion. With an amoxicillin-intermediate tolerant strain, 24-h bacterial clearance was similar (5.4 versus 8.3 log(10) CFU/ml, P < 0.05), but 12 h after treatment completion, lung homogenates contained 3.3 log(10) CFU/ml. Similar results were obtained with an amoxicillin-resistant and -tolerant strain. Day 10 survival rates were usually similar across strains. Amoxicillin with pharmacokinetics simulating 1 g/8 h orally in humans is bactericidal in mice with pneumonia due to S. pneumoniae for which MICs were 2 to 4 microg/ml. The killing rate depends not only on resistance but also on tolerance of the S. pneumoniae strains.

Differential activation of inflammatory pathways in A549 type II pneumocytes by Streptococcus pneumoniae strains with different adherence properties

Background

Adherence of Streptococcus pneumoniae bacteria to lung cells is a first step in the progression from asymptomatic carriage to pneumonia. Adherence abilities vary widely among S. pneumoniae patient isolates. In this study, the binding properties of S. pneumoniae isolates and the effects of binding on activation of the Nuclear Factor-Kappa-B (NFκB) pathway and cytokine secretion by type II pneumocytes were measured.

Methods

Mechanisms of high- and low-binding S. pneumoniae adherence to A549 cells were investigated by blocking putative receptors on bacteria and host cells with antibody and by eluting choline-binding proteins off of bacterial surfaces. NFκB activation was measured by western blot and immunocytochemistry and cytokine secretion was detected by a protein array.

Results

This study shows that S. pneumoniae isolates from pneumonia patients (n = 298) can vary by as much as 1000-fold in their ability to bind to human lung epithelial cells. This difference resulted in differential activation of the NFκB pathway. High-, but not low-binding S. pneumoniae used Choline-binding protein A (CbpA) to bind to complement component C3 on epithelial cell surfaces. Interleukin-8 (IL-8) was the only cytokine secreted by cells treated with either low- or high-binding S. pneumoniae.

Conclusion

These results indicate that S. pneumoniae clinical isolates are not homogeneous in their interaction with host epithelial cells. The differential activation of host cells by high- and low-binding S. pneumoniae strains could have implications for the treatment of pneumococcal pneumonia and for vaccine development.

Telithromycin in the treatment of acute bacterial sinusitis, acute exacerbations of chronic bronchitis, and community-acquired pneumonia

Acute bacterial sinusitis (ABS), acute exacerbations of chronic bronchitis (AECB), and community-acquired pneumonia (CAP) are common conditions and constitute a substantial socioeconomic burden. The ketolides are a new class of antibacterials with a targeted spectrum of antibacterial activity. In vitro, telithromycin is active against common bacterial pathogens that cause upper and lower respiratory tract infections, including some isolates that are resistant to other antibiotic classes. In 2004, telithromycin was the first ketolide antibiotic approved for clinical use by the US Food and Drug Administration for the treatment of adult outpatients with ABS, AECB, and mild-to-moderate CAP. This review discusses the use of telithromycin in the treatment of these infections, providing an overview of its antibacterial activity, pharmacokinetic and pharmacodynamic properties, clinical efficacy, and tolerability-safety, and concludes that telithromycin is an appropriate option for the treatment of community-acquired ABS, AECB, and mild-to-moderate CAP.

In vitro selection of resistance to clarithromycin in Streptococcus pneumoniae clinical isolates

In this study the effects of exposure to serum, lung and breakpoint concentrations on Streptococcus pneumoniae susceptibility to clarithromycin, azithromycin, amoxicillin/clavulanate, levofloxacin and moxifloxacin were evaluated. Development of resistance was determined by multi-step and single-step methodologies. In the first experimental set, minimum inhibitory concentrations (MICs) were determined after 10 passages on antibiotic-gradient plates and 10 passages on antibiotic-free plates. Acquisition of resistance was defined as an increase of > or = 4-fold from the starting MIC. In single-step studies, the rate of spontaneous mutations was calculated after a passage on antibiotic-containing agar plates. Azithromycin and levofloxacin gave the highest number of strains with MIC increased of at least 4 times the starting value, followed by moxifloxacin and by clarithromycin which only at the lowest concentration tested selected for resistance in 5 strains. Amoxicillin/clavulanate never displayed > or = 4-fold MIC increase. Frequencies of mutation were lower for clarithromycin and moxifloxacin than for the comparators. At lung concentrations clarithromycin had limited potential to select for resistance.