The burden of community-acquired bacterial pneumonia in the era of antibiotic resistance

Results from the Survey of Antibiotic Resistance (SOAR) 2015-18 in Tunisia, Kenya and Morocco: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

OBJECTIVES

To determine antibiotic susceptibility of community-acquired respiratory tract infection (CA-RTI) isolates of Streptococcus pneumoniae and Haemophilus influenzae collected in 2015-18 from Tunisia, Kenya and Morocco.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

S. pneumoniae isolates from Tunisia (n = 79), Kenya (n = 44) and Morocco (n = 19) and H. influenzae isolates (n = 74) from Tunisia only were collected and analysed. Low antibiotic susceptibility was observed in S. pneumoniae from Tunisia, with >90% susceptible only to the fluoroquinolones (all breakpoints), penicillin (CLSI IV and EUCAST high-dose) and ceftriaxone (CLSI, EUCAST high-dose and PK/PD breakpoints). In addition, isolate susceptibility in Kenya was >90% to amoxicillin and amoxicillin/clavulanic acid (CLSI and PK/PD breakpoints). Antibiotic activity was highest in Morocco, where ≥89.5% of pneumococci were susceptible to most antibiotics, excluding trimethoprim/sulfamethoxazole (68.4% by CLSI or PK/PD and 79%-84.2% by EUCAST), macrolides (79%-84.2% by all breakpoints) and cefaclor (0% by EUCAST and 52.6% by PK/PD). The majority (≥86.5%) of H. influenzae isolates from Tunisia were susceptible to most antibiotics by all available breakpoints, except ampicillin and amoxicillin (almost one-third were β-lactamase positive), trimethoprim/sulfamethoxazole (51.4%-56.8%), cefaclor (1.4% by PK/PD), cefuroxime (4.1% by EUCAST), macrolides (1.4%-2.7% by PK/PD) and cefdinir (66.2% by PK/PD). The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified.

CONCLUSIONS

Low antibiotic susceptibility was observed in S. pneumoniae from Tunisia, but susceptibility was higher in isolates from Kenya and highest in those from Morocco. H. influenzae from Tunisia were highly susceptible to most antibiotics. These factors are important in decision making for empirical therapy of CA-RTIs.

Results from the Survey of Antibiotic Resistance (SOAR) 2015-17 in the Middle East (Kuwait, Lebanon and Saudi Arabia): data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

OBJECTIVES

To determine antibiotic susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolates from community-acquired respiratory tract infections (CA-RTIs) collected in 2015-17 from Kuwait, Lebanon and Saudi Arabia.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

A total of 139 S. pneumoniae isolates were collected from four centres in Kuwait, Lebanon and Saudi Arabia in 2015-17 and 55 H. influenzae isolates were collected and analysed from Saudi Arabia over the same time period. Pneumococci from all three countries were commonly non-susceptible to penicillin based on CLSI oral or low-dose IV penicillin using EUCAST breakpoints (39% in Kuwait to 57.1% in Lebanon) but by CLSI IV and EUCAST high-dose breakpoints most isolates were susceptible (∼90% in Kuwait and Saudi Arabia, and 100% in Lebanon). Isolates from Lebanon were highly susceptible to most other antibiotics (>90%) except cefaclor, oral cefuroxime and cefpodoxime (EUCAST breakpoints only). Overall, susceptibility was significantly lower in Kuwait and Saudi Arabia than Lebanon. Although all H. influenzae isolates (Saudi Arabia only) were β-lactamase negative, 3.6% and 12.7% were ampicillin resistant by CLSI and EUCAST breakpoints, respectively. Otherwise susceptibility was high in H. influenzae. The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified.

CONCLUSIONS

Relatively low antibiotic susceptibility was observed in S. pneumoniae from Kuwait and Saudi Arabia in contrast to Lebanon, where rates of susceptibility were generally higher. Isolates of H. influenzae from Saudi Arabia were susceptible to most antibiotics. These factors are important in decision making for empirical therapy of CA-RTIs.

Results from the Survey of Antibiotic Resistance (SOAR) 2015-17 in Pakistan: data based on CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints

OBJECTIVES

To determine antibiotic susceptibility of community-acquired respiratory tract infection (CA-RTI) isolates of Streptococcus pneumoniae and Haemophilus influenzae collected in 2015-17 from Pakistan.

METHODS

MICs were determined by CLSI broth microdilution and susceptibility was assessed using CLSI, EUCAST (dose-specific) and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

A total of 94 S. pneumoniae and 122 H. influenzae isolates were collected. Susceptibility to penicillin was noted in 23.4% of the S. pneumoniae isolates by CLSI oral/EUCAST low-dose IV breakpoints, although by CLSI IV and EUCAST high-dose breakpoints all isolates were characterized as susceptible. Susceptibility to trimethoprim/sulfamethoxazole (10.6%), macrolides (33%) and cefaclor (28.7%) was low but higher susceptibility was observed to ceftriaxone (100%), amoxicillin and amoxicillin/clavulanic acid (98.9%), cefuroxime (oral, 97.9%), cefpodoxime (96.8%), fluoroquinolones (93.6%-96.8%) and cefdinir (76.6%) by CLSI breakpoints. However, using EUCAST breakpoints, susceptibility to cefpodoxime (70.2%) and cefuroxime (oral, 61.7%) was reduced. H. influenzae isolates were almost all β-lactamase negative (96.7%). Using CLSI breakpoints, ≥93.4% of isolates were susceptible to all antibiotics tested except fluoroquinolones (75.4%-77.1%) and trimethoprim/sulfamethoxazole (41%). The proportion of isolates susceptible using EUCAST breakpoints was similar or identical for penicillins, trimethoprim/sulfamethoxazole and the cephalosporins that have EUCAST breakpoints; the proportion of isolates susceptible using EUCAST breakpoints was similar or identical to that using CSLI breakpoints except for cefuroxime (oral), where only 1.6% of isolates were considered susceptible. Susceptibility of H. influenzae to fluoroquinolones was also lower by EUCAST breakpoints (33.6%-34.4%). The application of different EUCAST breakpoints for low and higher doses for some of the antibiotics (amoxicillin, amoxicillin/clavulanic acid, ampicillin, penicillin, ceftriaxone, clarithromycin, erythromycin, levofloxacin and trimethoprim/sulfamethoxazole) allowed, for the first time in a SOAR study, the effect of raising the dosage on susceptibility to be quantified.

CONCLUSIONS

Antibiotic susceptibility in these important respiratory tract pathogens varied in Pakistan based on different breakpoints. These data are important for empirical therapy choices in the treatment of CA-RTIs.

In vitro susceptibility of common bacterial pathogens causing respiratory tract infections in Canada to lefamulin, a new pleuromutilin

Background

Community-acquired pneumonia (CAP) is a significant global health concern. Pathogens causing CAP demonstrate increasing resistance to commonly prescribed empiric treatments. Resistance in Streptococcus pneumoniae, the most prevalent bacterial cause of CAP, has been increasing worldwide, highlighting the need for improved antibacterial agents. Lefamulin, a novel pleuromutilin, is a recently approved therapeutic agent highly active against many lower respiratory tract pathogens. However, to date minimal data are available to describe the in vitro activity of lefamulin against bacterial isolates associated with CAP.

Methods

Common bacterial causes of CAP obtained from both lower respiratory and blood specimen isolates cultured by hospital laboratories across Canada were submitted to the annual CANWARD study's coordinating laboratory in Winnipeg, Canada, from January 2015 to October 2018. A total of 876 bacterial isolates were tested against lefamulin and comparator agents using the Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution method, and minimum inhibitory concentrations (MICs) were interpreted using accepted breakpoints.

Results

All S. pneumoniae isolates tested from both respiratory (n = 315) and blood specimens (n = 167) were susceptible to lefamulin (MIC ≤0.5 μg/mL), including isolates resistant to penicillins, clarithromycin, doxycycline, and trimethoprim-sulfamethoxazole. Lefamulin also inhibited 99.0% of Haemophilus influenzae isolates (regardless of β-lactamase production) (99 specimens; MIC ≤2 μg/mL) and 95.7% of methicillin-susceptible Staphylococcus aureus (MSSA) (MIC ≤0.25 μg/mL; 70 specimens) at their susceptible breakpoints. Conclusions: Lefamulin demonstrated potent in vitro activity against all respiratory isolates tested and may represent a significant advancement in empiric treatment options for CAP.

Activity of novel lactone ketolide nafithromycin against multicentric invasive and non-invasive pneumococcal isolates collected in India

Background

India is among the nations reporting substantial healthcare burden linked to pneumococcal infections. Nafithromycin is a novel lactone ketolide antibiotic, which recently entered Phase 3 development in India for the indication of community-acquired bacterial pneumonia (CABP).

Objectives

To assess the in vitro activity of nafithromycin against serotyped invasive and non-invasive Streptococcus pneumoniae isolates, collected from nine medical centres across India.

Methods

A total of 534 isolates of S. pneumoniae were collected during 2015–20 and serotyped as per CDC protocol. A subset of erythromycin-non-susceptible S. pneumoniae (n = 200) was screened for the presence of erm(B) and mef(A/E) genes. A subset of MDR isolates (n = 54) were also subjected to MLST. The MICs of antibiotics were determined by the reference agar-dilution method (CLSI). Susceptibilities of the comparators were interpreted as per CLSI criteria.

Results

Fifty-nine distinct serotypes were identified among the 534 isolates. Among erythromycin-non-susceptible isolates, erm(B) and mef(A/E) genes were found in 49% and 59% strains respectively, while MLST showed clonal diversity. Azithromycin (67.6% non-susceptible) and clindamycin (31.8% non-susceptible) showed limited activity. Penicillin (for non-meningitis) or quinolone non-susceptibility was low (<11% and <6%, respectively). Nafithromycin showed potent activity with MIC₅₀ and MIC₉₀ of 0.015–0.03 and 0.06 mg/L, respectively, regardless of the macrolide resistance mechanisms.

Conclusions

Indian pneumococcal isolates show poor susceptibilities to macrolides, in concordance with the global trend. Nafithromycin overcomes erm as well as mef-mediated macrolide resistance mechanisms expressed individually or concurrently in S. pneumoniae. This study supports continued clinical development of nafithromycin for pneumococcal infections including CABP.

Lefamulin efficacy and safety in a pooled phase 3 clinical trial population with community-acquired bacterial pneumonia and common clinical comorbidities

Background

Lefamulin, a first-in-class pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia (CABP), was noninferior to moxifloxacin in the Lefamulin Evaluation Against Pneumonia (LEAP) 1 intravenous-to-oral switch study and the LEAP 2 oral-only study. Using pooled LEAP 1/2 data, we examined lefamulin efficacy/safety overall and within subgroups of patients presenting with comorbidities typical in CABP management.

Methods

In LEAP 1, adults with CABP were randomized to receive intravenous lefamulin (150 mg every 12 h) for 5‒7 days or moxifloxacin (400 mg every 24 h) for 7 days, with optional intravenous-to-oral switch if predefined improvement criteria were met. In LEAP 2, adults with CABP were randomized to receive oral lefamulin (600 mg every 12 h) for 5 days or moxifloxacin (400 mg every 24 h) for 7 days. Both studies assessed early clinical response (ECR) at 96 ± 24 h after first study drug dose and investigator assessment of clinical response (IACR) at test-of-cure (5‒10 days after last dose). Pooled analyses of the overall population used a 10% noninferiority margin.

Results

Lefamulin (n = 646) was noninferior to moxifloxacin (n = 643) for ECR (89.3% vs 90.5%, respectively; difference  − 1.1%; 95% CI  − 4.4 to 2.2); IACR success rates at test-of-cure were similarly high (≥ 85.0%). High efficacy with both lefamulin and moxifloxacin was also demonstrated across all well-represented patient subgroups, including those with advanced age, diabetes mellitus, a history of cardiovascular diseases (e.g., hypertension, congestive heart failure, or arrhythmia) or chronic lung diseases (e.g., asthma or chronic obstructive pulmonary disease), elevated liver enzymes, or mild-to-moderate renal dysfunction. No new safety signals were identified.

Conclusions

Lefamulin may provide a valuable intravenous/oral monotherapy alternative to fluoroquinolones or macrolides for empiric treatment of patients with CABP, including cases of patients at risk for poor outcomes due to age or various comorbidities.

Trial registration

ClinicalTrials.gov LEAP 1 (NCT02559310; Registration Date: 24/09/2015) and LEAP 2 (NCT02813694; Registration Date: 27/06/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01472-z.

Early detection of drug-resistant Streptococcus pneumoniae and Haemophilus influenzae by quantitative flow cytometry

Early detection of drug resistance contributes to combating drug-resistant bacteria and improving patient outcomes. Microbial testing in the laboratory is essential for treating infectious diseases because it can provide critical information related to identifying pathogenic bacteria and their resistance profiles. Despite these clinical requirements, conventional phenotypic testing is time-consuming. Additionally, recent rapid drug resistance tests are not compatible with fastidious bacteria such as Streptococcus and Haemophilus species. In this study, we validated the feasibility of direct bacteria counting using highly sensitive quantitative flow cytometry. Furthermore, by combining flow cytometry and a nucleic acid intercalator, we constructed a highly sensitive method for counting viable fastidious bacteria. These are inherently difficult to measure due to interfering substances from nutrients contained in the medium. Based on the conventional broth microdilution method, our method acquired a few microliter samples in a time series from the same microplate well to exclude the growth curve inconsistency between the samples. Fluorescent staining and flow cytometry measurements were completed within 10 min. Therefore, this approach enabled us to determine antimicrobial resistance for these bacteria within a few hours. Highly sensitive quantitative flow cytometry presents a novel avenue for conducting rapid antimicrobial susceptibility tests.

Omadacycline vs moxifloxacin in adults with community-acquired bacterial pneumonia

OBJECTIVE

Community-acquired bacterial pneumonia (CABP) is a major clinical burden worldwide. In the phase III OPTIC study (NCT02531438) in CABP, omadacycline was found to be non-inferior to moxifloxacin for investigator-assessed clinical response (IACR) at post-treatment evaluation (PTE, 5-10 days after last dose). This article reports the efficacy findings, as specified in the European Medicines Agency (EMA) guidance.

METHODS

Patients were randomized 1:1 to omadacycline 100 mg intravenously (every 12 h for two doses, then every 24 h) with optional transition to 300 mg orally after 3 days, or moxifloxacin 400 mg intravenously (every 24 h) with optional transition to 400 mg orally after 3 days. The total treatment duration was 7-14 days. The primary endpoint for EMA efficacy analysis was IACR at PTE in patients with Pneumonia Patient Outcomes Research Team (PORT) risk class III and IV.

RESULTS

In total, 660 patients were randomized as PORT risk class III and IV. Omadacycline was non-inferior to moxifloxacin at PTE. The clinical success rates were 88.4% and 85.2%, respectively [intent-to-treat population; difference 3.3; 97.5% confidence interval (CI) -2.7 to 9.3], and 92.5% and 90.5%, respectively (clinically evaluable population; difference 2.0; 97.5% CI 3.2-7.4). Clinical success rates with omadacycline and moxifloxacin were similar against identified pathogens and across key subgroups.

CONCLUSIONS

Omadacycline was non-inferior to moxifloxacin for IACR at PTE, with high clinical success across pathogen types and patient subgroups.

Burden of pneumococcal pneumonia requiring ICU admission in France: 1-year prognosis, resources use, and costs

Background

Community-acquired pneumonia (CAP), especially pneumococcal CAP (P-CAP), is associated with a heavy burden of illness as evidenced by high rates of intensive care unit (ICU) admission, mortality, and costs. Although well-defined acutely, determinants influencing long-term burden are less known. This study assessed determinants of 28-day and 1-year mortality and costs among P-CAP patients admitted in ICUs.

Methods

Data regarding all hospital and ICU stays in France in 2014 were extracted from the French healthcare administrative database. All patients admitted in the ICU with a pneumonia diagnosis were included, except those hospitalized for pneumonia within the previous 3 months. The pneumococcal etiology and comorbidities were captured. All hospital stays were included in the cost analysis. Comorbidities and other factors effect on the 28-day and 1-year mortality were assessed using a Cox regression model. Factors associated with increased costs were identified using log-linear regression models.

Results

Among 182,858 patients hospitalized for CAP in France for 1 year, 10,587 (5.8%) had a P-CAP, among whom 1665 (15.7%) required ICU admission. The in-hospital mortality reached 22.8% at day 28 and 32.3% at 1 year. The mortality risk increased with age > 54 years, malignancies (hazard ratio (HR) 1.54, 95% CI [1.23–1.94], p = 0.0002), liver diseases (HR 2.08, 95% CI [1.61–2.69], p < 0.0001), and the illness severity at ICU admission. Compared with non-ICU-admitted patients, ICU survivors remained at higher risk of 1-year mortality. Within the following year, 38.2% (516/1350) of the 28-day survivors required at least another hospital stay, mostly for respiratory diseases. The mean cost of the initial stay was €19,008 for all patients and €11,637 for subsequent hospital stays within 1 year. One-year costs were influenced by age (lower in patients > 75 years old, p = 0.008), chronic cardiac (+ 11% [0.02–0.19], p = 0.019), and respiratory diseases (+ 11% [0.03–0.18], p = 0.006).

Conclusions

P-CAP in ICU-admitted patients was associated with a heavy burden of mortality and costs at one year. Older age was associated with both early and 1-year increased mortality. Malignant and chronic liver diseases were associated with increased mortality, whereas chronic cardiac failure and chronic respiratory disease with increased costs.

Trial registration

N/A (study on existing database)

The search for novel treatment strategies for Streptococcus pneumoniae infections

This review provides an overview of the most important novel treatment strategies against Streptococcus pneumoniae infections published over the past 10 years. The pneumococcus causes the majority of community-acquired bacterial pneumonia cases, and it is one of the prime pathogens in bacterial meningitis. Over the last 10 years, extensive research has been conducted to prevent severe pneumococcal infections, with a major focus on (i) boosting the host immune system and (ii) discovering novel antibacterials. Boosting the immune system can be done in two ways, either by actively modulating host immunity, mostly through administration of selective antibodies, or by interfering with pneumococcal virulence factors, thereby supporting the host immune system to effectively overcome an infection. While several of such experimental therapies are promising, few have evolved to clinical trials. The discovery of novel antibacterials is hampered by the high research and development costs versus the relatively low revenues for the pharmaceutical industry. Nevertheless, novel enzymatic assays and target-based drug design, allow the identification of targets and the development of novel molecules to effectively treat this life-threatening pathogen.

Clinical and Microbiologic Efficacy and Safety of Imipenem/Cilastatin/Relebactam in Complicated Infections: A Meta-analysis

BACKGROUND

Antimicrobial resistance is on the rise. The use of redundant and inappropriate antibiotics is contributing to recurrent infections and resistance. Newer antibiotics with more robust coverage for Gram-negative bacteria are in great demand for complicated urinary tract infections (cUTIs), complicated intra-abdominal infections (cIAIs), hospital-acquired bacterial pneumonia (HABP), and ventilator-associated bacterial pneumonia (VABP).

MATERIALS AND METHODS

We performed this meta-analysis to evaluate the efficacy and safety profile of a new antibiotic, Imipenem/cilastatin/relebactam, compared to other broad-spectrum antibiotics for complicated infections. We conducted a systemic review search on PubMed, Embase, and Central Cochrane Registry. We included randomized clinical trials-with the standard of care as comparator arm with Imipenem/cilastatin/relebactam as intervention arm. For continuous variables, the mean difference was used. For discrete variables, we used the odds ratio. For effect sizes, we used a confidence interval of 95%. A P-value of less than 0.05 was used for statistical significance. Analysis was done using a random-effects model irrespective of heterogeneity. Heterogeneity was evaluated using the I² statistic.

RESULTS

The authors observed similar efficacy at clinical and microbiologic response levels on early follow-up and late follow-up compared to the established standard of care. The incidence of drug-related adverse events, serious adverse events, and drug discontinuation due to adverse events were comparable across both groups.

CONCLUSION

Imipenem/cilastatin/relebactam has a non-inferior safety and efficacy profile compared to peer antibiotics to treat severe bacterial infections (cUTIs, cIAIs, HABP, VABP).

The traditional use of southern African medicinal plants for the treatment of bacterial respiratory diseases: A review of the ethnobotany and scientific evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Multiple plant species were used traditionally in southern Africa to treat bacterial respiratory diseases. This review summarises this usage and highlights plant species that are yet to be verified for these activities.

AIM OF THE STUDY

This manuscript reviews the traditional usage of southern African plant species to treat bacterial respiratory diseases with the aim of highlighting gaps in the literature and focusing future studies.

MATERIALS AND METHODS

An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify southern African plants which are used in traditional southern African medicine to treat bacterial respiratory diseases. We also searched for southern African plants whose inhibitory activity against bacterial respiratory pathogens has been conmfirmed, to highlight gaps in the literature and focus future studies.

RESULTS

One hundred and eighty-seven southern African plant species are recorded as traditional therapies for bacterial respiratory infections. Scientific evaluations of 178 plant species were recorded, although only 42 of these were selected for screening on the basis of their ethnobotanical uses. Therefore, the potential of 146 species used teraditionally to treat bacterial respiratory diseases are yet to be verified.

CONCLUSIONS

The inhibitory properties of southern African medicinal plants against bacterial respiratory pathogens is relatively poorly explored and the antibacterial activity of most plant species remains to be verified.

In vitro activity of delafloxacin against highly levofloxacin-resistant invasive isolates of Streptococcus pneumoniae

INTRODUCTION

We report the activity of delafloxacin, a new fluoroquinolone with high affinity for both topoisomerase IV and DNA gyrase, against highly-levofloxacin-resistant invasive strains of Streptococcus pneumoniae.

METHODS

A total of 173 highly-levofloxacin-resistant (MIC>32mg/L) S. pneumoniae invasive isolates were studied. The strains were isolated from blood (n=162) and other sterile fluids (n=11). Serotyping was performed by the Pneumotest-Latex and Quellung reaction. Delafloxacin, levofloxacin, penicillin, cefotaxime, erythromycin and vancomycin MICs were determined by the gradient diffusion method following EUCAST guidelines and breakpoints.

RESULTS

Among the isolates, 32.9% were penicillin non-susceptible, 19.7% cefotaxime non-susceptible, and 76.9% erythromycin resistant. All were susceptible to vancomycin. Delafloxacin MIC50 and MIC90 (mg/L) values were 0.064 and 0.12, respectively; 60% (15/25) of serotype 9V isolates showed delafloxacin MICs≥0.12mg/L.

CONCLUSIONS

Delafloxacin was very active against highly-levofloxacin-resistant invasive isolates of S. pneumoniae. Isolates belonging to serotype 9V showed higher delafloxacin MIC values.

Ambient air pollution and respiratory bacterial infections, a troubling association: epidemiology, underlying mechanisms, and future challenges

The World Health Organization attributed more than four million premature deaths to ambient air pollution in 2016. Numerous epidemiologic studies demonstrate that acute respiratory tract infections and exacerbations of pre-existing chronic airway diseases can result from exposure to ambient (outdoor) air pollution. In this context, the atmosphere contains both chemical and microbial pollutants (bioaerosols), whose impact on human health remains unclear. Therefore, this review: summarises the findings from recent studies on the association between exposure to air pollutants-especially particulate matter and ozone-and onset or exacerbation of respiratory infections (e.g. pneumonia, cystic fibrosis lung infection, and tuberculosis); discusses the mechanisms underlying the relationship between air pollution and respiratory bacterial infections, which is necessary to define prevention and treatment strategies; demonstrates the relevance of air pollution modelling in investigating and preventing the impact of exposure to air pollutants on human health; and outlines future actions required to improve air quality and reduce morbidity and mortality related to air pollution.

Platelets and Their Role in the Pathogenesis of Cardiovascular Events in Patients With Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality throughout the world with much recent and ongoing research focused on the occurrence of cardiovascular events (CVEs) during the infection, which are associated with adverse short-term and long-term survival. Much of the research directed at unraveling the pathogenesis of these events has been undertaken in the settings of experimental and clinical CAP caused by the dangerous, bacterial respiratory pathogen, Streptococcus pneumoniae (pneumococcus), which remains the most common bacterial cause of CAP. Studies of this type have revealed that although platelets play an important role in host defense against infection, there is also increasing recognition that hyperactivation of these cells contributes to a pro-inflammatory, prothrombotic systemic milieu that contributes to the etiology of CVEs. In the case of the pneumococcus, platelet-driven myocardial damage and dysfunction is exacerbated by the direct cardiotoxic actions of pneumolysin, a major pore-forming toxin of this pathogen, which also acts as potent activator of platelets. This review is focused on the role of platelets in host defense against infection, including pneumococcal infection in particular, and reviews the current literature describing the potential mechanisms by which platelet activation contributes to cardiovascular complications in CAP. This is preceded by an evaluation of the burden of pneumococcal infection in CAP, the clinical features and putative pathogenic mechanisms of the CVE, and concludes with an evaluation of the potential utility of the anti-platelet activity of macrolides and various adjunctive therapies.

Lefamulin vs moxifloxacin for community-acquired bacterial pneumonia

Lefamulin is a novel pleuromutilin antibiotic with potent in vitro activity against key community-acquired bacterial pneumonia (CABP) pathogens. However, the clinical efficacy and safety of lefamulin for treating CABP remains unclear.An integrated analysis of 2 phase III trials investigating the clinical efficacy and safety of lefamulin vs moxifloxacin in the treatment of CABP was conducted.A total of 1289 patients (lefamulin group: 646 and moxifloxacin group: 643) were included in this analysis. The early clinical response rate was 89.3% and 90.5% among lefamulin and moxifloxacin group, respectively. Lefamulin was noninferior to moxifloxacin (89.3% vs 90.5%, RR: 0.99, 95% CI: 0.95-1.02, I = 0%). In terms of clinical response at test of cure, no significant difference was observed between the lefamulin and moxifloxacin groups (for modified intention to treat population, RR: 0.98, 95% CI: 0.94-1.02, I = 0%; for clinically evaluable population, RR: 0.96, 95% CI: 0.93-1.00, I = 0%). In the subgroup analysis, the early clinical response rate at early clinical assessment and clinical response rate at test of cure of lefamulin was similar to that of moxifloxacin across different subgpopulations and all baseline CABP pathogens. Lefamulin was associated with a similar risk of adverse events as moxifloxacin.Clinical efficacy and tolerability for lefamulin in the treatment of CABP were similar to those for moxifloxacin.

In vitro and in vivo Evaluation of in silico Predicted Pneumococcal UDPG:PP Inhibitors

Pneumonia, of which Streptococcus pneumoniae is the most common causative agent, is considered one of the three top leading causes of death worldwide. As seen in other bacterial species, antimicrobial resistance is on the rise for this pathogen. Therefore, there is a pressing need for novel antimicrobial strategies to combat these infections. Recently, uridine diphosphate glucose pyrophosphorylase (UDPG:PP) has been put forward as a potential drug target worth investigating. Moreover, earlier research demonstrated that streptococci lacking a functional galU gene (encoding for UDPG:PP) were characterized by significantly reduced in vitro and in vivo virulence. Therefore, in this study we evaluated the anti-virulence activity of potential UDPG:PP inhibitors. They were selected in silico using a tailor-made streptococcal homology model, based on earlier listerial research. While the compounds didn’t affect bacterial growth, nor affected in vitro adhesion to and phagocytosis in macrophages, the amount of polysaccharide capsule was significantly reduced after co-incubation with these inhibitors. Moreover, co-incubation proved to have a positive effect on survival in an in vivo Galleria mellonella larval infection model. Therefore, rather than targeting bacterial survival directly, these compounds proved to have an effect on streptococcal virulence by lowering the amount of polysaccharide and thereby probably boosting recognition of this pathogen by the innate immune system. While the compounds need adaptation to broaden their activity to more streptococcal strains rather than being strain-specific, this study consolidates UDPG:PP as a potential novel drug target.

Clinical Analysis of 25 COVID-19 Infections in Children

BACKGROUND

To describe the characteristics of clinical manifestations of children with 2019 novel coronavirus (2019-nCoV) infection in Chongqing.

METHODS

All 25 children with laboratory-confirmed 2019-nCoV infection by real-time reverse transcription-PCR (RNA-PCR) were admitted from the 4 designated treatment hospitals of 2019-nCoV in Chongqing from January 19 to March 12, 2020. Clinical data and epidemiologic history of these patients were retrospectively collected and analyzed.

RESULTS

The diagnosis was confirmed through RNA-PCR testing. Among the 25 cases, 14 were males and 11 were females. The median age was 11.0 (6.3-14.5) years (range 0.6-17.0 years). All children were related to a family cluster outbreak, and 7 children (28%) with a travel or residence history in Hubei Province. These patients could be categorized into different clinical types, including 8 (32%) asymptomatic, 4 (16%) very mild cases and 13 (52%) common cases. No severe or critical cases were identified. The most common symptoms were cough (13 cases, 52%) and fever (6 cases, 24%). The duration time of clinical symptoms was 13.0 (8.0-25.0) days. In the 25 cases, on admission, 21 cases (84%) had normal white blood cell counts, while only 2 cases (8%) more than 10 × 10/L and 2 cases (8%) less than 4 × 10/L, respectively; 22 cases(88%) had normal CD4+ T lymphocyte counts, while in the remaining 3 cases(8%) this increased mildly; 23 cases had normal CD8+ T lymphocyte counts, while in the remaining 2 cases (8%) CD8+ T lymphocyte counts were mildly increased as well. All Lymphocyte counts were normal. There were no statistical differences of lab results between the groups of asymptomatic cases, mild cases and common cases. There were only 13 cases with abnormal CT imaging, most of which were located in the subpleural area of the bottom of the lung. All patients were treated with interferon, 6 cases combined with Ribavirin, and 12 cases combined with lopinavir or ritonavir. The days from onset to RNA turning negative was 15.20 ± 6.54 days. There was no significant difference of RNA turning negative between the groups of interferon, interferon plus ribavirin and interferon plus lopinavir or ritonavir treatment. All the cases recovered and were discharged from hospital.

CONCLUSIONS

The morbidity of 2019-nCoV infection in children is lower than in adults and the clinical manifestations and inflammatory biomarkers in children are nonspecific and milder than that in adults. RNA-PCR test is still the most reliable diagnostic method, especially for asymptomatic patients.

Characteristics and outcomes among a hospitalized patient cohort with Streptococcus pneumoniae infection

Infection due to Streptococcus pneumoniae (SP) requiring hospitalization is common. However, recent clinical studies describing patient characteristics and outcomes for SP infection in adults requiring hospitalization are lacking. Our goal was to evaluate patient characteristics, contemporary antibiotic resistance, and clinical outcomes among hospitalized adults with SP infections.A retrospective cohort study was conducted at Barnes-Jewish Hospital (1350 beds) in St. Louis, Missouri, USA for years 2012 through 2016. During the study period, 358 hospitalized adults, excluding those with meningitis, were identified with SP infection. Forty-four patients (12.3%) died within 30 days of the identification of their infection. Among these infections, 99 (27.7%) were assessed to be hospital-acquired and 259 (72.3%) were community-onset infections. The majority of infections involved the respiratory tract (88.5%). Azithromycin resistance was the most common antibiotic resistance at 51.4%, followed by enteral penicillin resistance (45.3%), trimethoprim-sulfamethoxazole (34.1%), second-generation cephalosporin (cefuroxime) (30.7%), and meropenem (22.6%). There were 70 isolates (19.6%) classified as multidrug resistant. Independent predictors of hospital mortality included increasing weight in 1-kilogram increments (adjusted odds ratio [AOR], 1.02; 95% CI, 1.01 - 1.02; P = .048), increasing Charlson Comorbidity Index scores (AOR, 1.31; 95% CI, 1.21 - 1.42; P = .001), and the presence of septic shock (AOR, 3.89; 95% CI, 2.31 - 6.57; P = .009). The median [interquartile range] hospital length of stay was 8.1 days [4.5 days, 16.8 days].Hospitalized patients with infection attributed to SP have significant 30-day mortality and use of hospital resources. Antibiotic resistance is common among isolates associated with infection. Determinants of mortality are primarily severity of illness, underlying comorbidities and increasing patient weight. Efforts to improve the treatment and prevention of SP infections are needed.

Antibiotic-Resistant Community-Acquired Bacterial Pneumonia

Antimicrobial resistance is a global concern, and prudent use of antibiotics is essential to preserve the current armamentarium of effective drugs. Acute respiratory tract infection is the most common reason for antibiotic prescription in adults. In particular, community-acquired pneumonia poses a significant health challenge and economic burden globally, especially in the current landscape of a dense and aging population. By updating the knowledge on the common antimicrobial-resistant pathogens in community-acquired respiratory tract infections, their prevalence, and resistance may pave the way to enhancing appropriate antibiotic use in the ambulatory and health care setting.

Proteomic Investigation Uncovers Potential Targets and Target Sites of Pneumococcal Serine-Threonine Kinase StkP and Phosphatase PhpP

Like eukaryotes, different bacterial species express one or more Ser/Thr kinases and phosphatases that operate in various signaling networks by catalyzing phosphorylation and dephosphorylation of proteins that can immediately regulate biochemical pathways by altering protein function. The human pathogen Streptococcus pneumoniae encodes a single Ser/Thr kinase-phosphatase couple known as StkP-PhpP, which has shown to be crucial in the regulation of cell wall synthesis and cell division. In this study, we applied proteomics to further understand the physiological role of pneumococcal PhpP and StkP with an emphasis on phosphorylation events on Ser and Thr residues. Therefore, the proteome of the non-encapsulated D39 strain (WT), a kinase (ΔstkP), and phosphatase mutant (ΔphpP) were compared in a mass spectrometry based label-free quantification experiment. Results show that a loss of function of PhpP causes an increased abundance of proteins in the phosphate uptake system Pst. Quantitative proteomic data demonstrated an effect of StkP and PhpP on the two-component systems ComDE, LiaRS, CiaRH, and VicRK. To obtain further information on the function, targets and target sites of PhpP and StkP we combined the advantages of phosphopeptide enrichment using titanium dioxide and spectral library based data evaluation for sensitive detection of changes in the phosphoproteome of the wild type and the mutant strains. According to the role of StkP in cell division we identified several proteins involved in cell wall synthesis and cell division that are apparently phosphorylated by StkP. Unlike StkP, the physiological function of the co-expressed PhpP is poorly understood. For the first time we were able to provide a list of previously unknown putative targets of PhpP. Under these new putative targets of PhpP are, among others, five proteins with direct involvement in cell division (DivIVA, GpsB) and peptidoglycan biosynthesis (MltG, MreC, MacP).

The 1-year economic burden of community-acquired pneumonia (CAP) initially managed in the outpatient setting in the USA

Aim: To assess the annual economic burden of community-acquired pneumonia (CAP) initially managed in the outpatient setting. Patients & methods: Patients with an outpatient diagnosis of CAP between January 2012 and December 2016 were identified from the IQVIA (Danbury, CT & Durham, NC, USA) Real-World Data Adjudicated Claims – US Database. All-cause and CAP-related healthcare resource utilization and costs were assessed over the 1-year follow-up. Generalized linear model examined adjusted total cost. Results: Among 256,916 patients with outpatient CAP, a tenth (10.6%) had ≥1 hospitalization and, of these, 18.7% had ≥1 CAP-related hospitalization. The mean total cost per patient was US$14,372; 10.9% was CAP-related and 26.1% was due to inpatient care. The adjusted mean total all-cause cost was US$13,788. Conclusion: Patients with outpatient CAP incurred a substantial annual economic burden.

The annual economic burden among patients hospitalized for community-acquired pneumonia (CAP): a retrospective US cohort study

Objective: To assess the 1-year economic burden among patients hospitalized for community-acquired pneumonia (CAP) in the US.Methods: Adult patients hospitalized for CAP between 1/2012 and 12/2016 were identified from the IQVIA hospital charge data master (CDM) linked to the IQVIA Real-World Data Adjudicated Claims - US Database (date of admission = index date). Patients had continuous enrollment 180-days pre- and 360-days post-index, and empiric antimicrobial treatment (monotherapy [EM] or combination therapy [EC]) and chest x-ray on the index date or day after. All-cause and CAP-related healthcare resource utilization and cost were assessed over the 1-year follow-up. Generalized linear models (GLM) examined adjusted total cost.Results: The cohort comprised 1624 patients hospitalized for CAP (mean age 50.3; 52.8% female). The majority (78.2%) initiated EC, most frequently with beta-lactams + macrolides (30.4%). The index hospitalization was associated with a mean length of stay (LOS) of 5.7 days and mean cost of $17,736; 22.7% had a transfer to the intensive care unit (ICU). All-cause readmission rates at 30- and 180-days were 8.8% and 20.1%, respectively. Mean annual all-cause total cost was $61,928; one-third (33.8%, $20,954) was related to CAP. The primary cost driver was inpatient care, which accounted for more than half (56.0%) of total all-cause cost and 94.3% of total CAP-related cost. Mean total inpatient cost was significantly higher among EC versus EM patients ($37,106 versus $25,999, p = .0399). Adjusted mean total all-cause cost was $55,391.Conclusions: Patients hospitalized for CAP incurred a significant annual economic burden, driven substantially by the high cost of hospitalizations.

A Phase 3 Study to Compare Delafloxacin With Moxifloxacin for the Treatment of Adults With Community-Acquired Bacterial Pneumonia (DEFINE-CABP)

BACKGROUND

The clinical and economic burden of community-acquired bacterial pneumonia (CABP) is significant and is anticipated to increase as the population ages and pathogens become more resistant. Delafloxacin is a fluoroquinolone antibiotic approved in the United States for the treatment of adults with acute bacterial skin and skin structure infections. Delafloxacin's shape and charge profile uniquely impact its spectrum of activity and side effect profile. This phase 3 study compared the efficacy and safety of delafloxacin with moxifloxacin for the treatment of CABP.

METHODS

A randomized, double-blind, comparator-controlled, multicenter, global phase 3 study compared the efficacy and safety of delafloxacin 300 mg twice daily or moxifloxacin 400 mg once daily in adults with CABP. The primary end point was early clinical response (ECR), defined as improvement at 96 (±24) hours after the first dose of study drug. Clinical response at test of cure (TOC) and microbiologic response were also assessed.

RESULTS

In the intent-to-treat analysis population (ITT), ECR rates were 88.9% in the delafloxacin group and 89.0% in the moxifloxacin group. Noninferiority of delafloxacin compared with moxifloxacin was demonstrated. At TOC in the ITT population, the success rates were similar between groups. Treatment-emergent adverse events that were considered at least possibly related to the study drug occurred in 65 subjects (15.2%) in the delafloxacin group and 54 (12.6%) in the moxifloxacin group.

CONCLUSIONS

Intravenous/oral delafloxacin monotherapy is effective and well tolerated in the treatment of adults with CABP, providing coverage for Gram-positive, Gram-negative, and atypical pathogens.

CLINICALTRIALSGOV IDENTIFIER

NCT03534622.

Cigarette smoke exposure induces expression of the pneumococcal erm(B) macrolide resistance gene

INTRODUCTION

Cigarette smoking is a well-recognized risk factor for development of severe, invasive pneumococcal disease. However, little is known about the direct effects of exposure to cigarette smoke on the virulence mechanisms of the pathogen, particularly in respect of resistance to macrolide antibiotics, which are widely used in the treatment of pneumococcal infection. This study aimed to investigate the effects of exposure to cigarette smoke condensate (CSC, 80 and 160 mg/L) and clarithromycin (2 and 8 mg/L), alone and in combination in vitro, on expression of the erm(B) and mef(A) macrolide resistance genes of strains 2507 and 521 (both serotype 23F), respectively, of the pneumococcus.

METHODS

Following exposure to CSC or clarithromycin, individually and in combination, erm(B) and mef(A) gene expression were measured by sequential extraction of RNA, conversion to and amplification of cDNA, and detection by qRT-PCR.

RESULTS

As expected, exposure of both test strains of the pneumococcus to clarithromycin resulted in substantial upregulation of both macrolide resistance genes, which was significantly (p<0.001) augmented by prior exposure to CSC in the case of erm(B), but not mef(A). Somewhat unexpectedly, exposure of strain 2507 to CSC (160 mg/L) alone (in the absence of clarithromycin) also resulted in significant (p<0.05) expression of the erm(B) gene.

CONCLUSION

Although the possible clinical significance remains to be established, these findings suggest that smoking may impede the efficacy of macrolide-based antimicrobial therapy by accelerating the onset and magnitude of erm(B)-mediated resistance, representing a novel pro-infective mechanism of smoking.

Oral Lefamulin vs Moxifloxacin for Early Clinical Response Among Adults With Community-Acquired Bacterial Pneumonia: The LEAP 2 Randomized Clinical Trial

IMPORTANCE

New antibacterials are needed to treat community-acquired bacterial pneumonia (CABP) because of growing antibacterial resistance and safety concerns with standard care.

OBJECTIVE

To evaluate the efficacy and adverse events of a 5-day oral lefamulin regimen in patients with CABP.

DESIGN, SETTING, AND PARTICIPANTS

A phase 3, noninferiority randomized clinical trial conducted at 99 sites in 19 countries that included adults aged 18 years or older with a Pneumonia Outcomes Research Team (PORT) risk class of II, III, or IV; radiographically documented pneumonia; acute illness; 3 or more CABP symptoms; and 2 or more vital sign abnormalities. The first patient visit was on August 30, 2016, and patients were followed up for 30 days; the final follow-up visit was on January 2, 2018.

INTERVENTIONS

Patients were randomized 1:1 to receive oral lefamulin (600 mg every 12 hours for 5 days; n = 370) or moxifloxacin (400 mg every 24 hours for 7 days; n = 368).

MAIN OUTCOMES AND MEASURES

The US Food and Drug Administration (FDA) primary end point was early clinical response at 96 hours (within a 24-hour window) after the first dose of either study drug in the intent-to-treat (ITT) population (all randomized patients). Responders were defined as alive, showing improvement in 2 or more of the 4 CABP symptoms, having no worsening of any CABP symptoms, and not receiving any nonstudy antibacterial drug for current CABP episode. The European Medicines Agency coprimary end points (FDA secondary end points) were investigator assessment of clinical response at test of cure (5-10 days after last dose) in the modified ITT population and in the clinically evaluable population. The noninferiority margin was 10% for early clinical response and investigator assessment of clinical response.

RESULTS

Among 738 randomized patients (mean age, 57.5 years; 351 women [47.6%]; 360 had a PORT risk class of III or IV [48.8%]), 707 (95.8%) completed the trial. Early clinical response rates were 90.8% with lefamulin and 90.8% with moxifloxacin (difference, 0.1% [1-sided 97.5% CI, -4.4% to ∞]). Rates of investigator assessment of clinical response success were 87.5% with lefamulin and 89.1% with moxifloxacin in the modified ITT population (difference, -1.6% [1-sided 97.5% CI, -6.3% to ∞]) and 89.7% and 93.6%, respectively, in the clinically evaluable population (difference, -3.9% [1-sided 97.5% CI, -8.2% to ∞]) at test of cure. The most frequently reported treatment-emergent adverse events were gastrointestinal (diarrhea: 45/368 [12.2%] in lefamulin group and 4/368 [1.1%] in moxifloxacin group; nausea: 19/368 [5.2%] in lefamulin group and 7/368 [1.9%] in moxifloxacin group).

CONCLUSIONS AND RELEVANCE

Among patients with CABP, 5-day oral lefamulin was noninferior to 7-day oral moxifloxacin with respect to early clinical response at 96 hours after first dose.

TRIAL REGISTRATIONS

ClinicalTrials.gov Identifier: NCT02813694; European Clinical Trials Identifier: 2015-004782-92.

Efficacy and Safety of Ceftaroline for the Treatment of Community-Acquired Pneumonia: A Systemic Review and Meta-Analysis of Randomized Controlled Trials

This study aimed to compare the clinical efficacy and safety of ceftaroline with those of ceftriaxone for treating community-acquired pneumonia (CAP). The PubMed, Cochrane Library, Embase, and clinicalTrials.gov databases were searched until April 2019. This meta-analysis only included randomized controlled trials (RCTs) that evaluated ceftaroline and ceftriaxone for the treatment of CAP. The primary outcome was the clinical cure rate, and the secondary outcome was the risk of adverse events (AEs). Five RCTs were included. Overall, at the test of cure (TOC), the clinical cure rate of ceftaroline was superior to the rates of ceftriaxone for the treatment of CAP (modified intent-to-treat population (MITT) population, odds ratio (OR) 1.61, 95% confidence interval (CI) 1.31–1.99, I² = 0%; clinically evaluable (CE) population, OR 1.38, 95% CI 1.07–1.78, I² = 14%). Similarly, the clinical cure rate of ceftaroline was superior to that of ceftriaxone at the end of therapy (EOT) (MITT population, OR 1.57, 95% CI 1.16–2.11, I² = 0%; CE population, OR 1.64, 95% CI 1.15–2.33, I² = 0%). For adult patients, the clinical cure rate of ceftaroline remained superior to that of ceftriaxone at TOC (MITT population, OR 1.66, 95% CI 1.34–2.06, I² = 0%; CE population, OR 1.39, 95% CI 1.08–1.80, I² = 30%) and at EOT (MITT population, OR 1.64, 95% CI 1.20–2.24, I² = 0%; CE population, OR 1.65, 95% CI 1.15–2.36, I² = 0%). Ceftaroline and ceftriaxone did not differ significantly in the risk of serious AEs, treatment-emergent AEs, and discontinuation of the study drug owing to an AE. In conclusion, the clinical efficacy of ceftaroline is similar to that of ceftriaxone for the treatment of CAP. Furthermore, this antibiotic is as tolerable as ceftriaxone.

Antibacterial Activity of Lefamulin against Pathogens Most Commonly Causing Community-Acquired Bacterial Pneumonia: SENTRY Antimicrobial Surveillance Program (2015-2016)

Lefamulin, the first semisynthetic pleuromutilin antibacterial for intravenous and oral treatment of community-acquired bacterial pneumonia (CABP), and comparators were evaluated for in vitro activity against a global collection of pathogens commonly causing CABP (n = 8595) from the 2015 and 2016 SENTRY Antimicrobial Surveillance Program. Lefamulin was highly active against the pathogens Streptococcus pneumoniae, including multidrug-resistant and extensively drug-resistant strains (MIC50/90 for total and resistant subsets, 0.06/0.12 μg/ml; 100% inhibited at ≤1 μg/ml), Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA; both MIC50/90, 0.06/0.12 μg/ml; 99.8% and 99.6% inhibited at ≤1 μg/ml, respectively), Haemophilus influenzae (MIC50/90, 0.5/1 μg/ml; 93.8% inhibited at ≤1 μg/ml), and Moraxella catarrhalis (MIC50/90, 0.06/0.12 μg/ml; 100% inhibited at ≤0.25 μg/ml), and its activity was unaffected by resistance to other antibacterial classes.