Genetic Adaptation and Acquisition of Macrolide Resistance in Haemophilus spp. during Persistent Respiratory Tract Colonization in Chronic Obstructive Pulmonary Disease (COPD) Patients Receiving Long-Term Azithromycin Treatment

Extensively drug-resistant Haemophilus influenzae isolated in Geneva, Switzerland

The emergence of multi-drug resistant (MDR) and even extensively drug-resistant (XDR) strains among H. influenzae was observed in some Asian countries. Herein, we reported the first XDR H. influenzae isolated in Geneva, Switzerland. This strain was isolated in a good-quality sputum sample from a 63 year-old male patient. There was no respiratory infection diagnosed at that time. The strain was non-typeable and pan-β-lactam resistant. According to whole genome sequencing analysis it belongs to sequence type 159 and the ST-107 clonal complex. It was classified into group III + regarding the amino acid substitutions identified in the transpeptidase domain of PBP3.

R, Baldaniya L, kaur J, Rani B, Beig M. Insights into Haemophilus macrolide resistance: A comprehensive systematic review and meta-analysis

BACKGROUND

Haemophilus spp., particularly Haemophilus influenzae, are major global pathogens causing various infections. Macrolides are crucial in treating these infections, but rising resistance to macrolides in Haemophilus spp. highlights the growing threat of antimicrobial resistance (AMR).

OBJECTIVE

This study aims to assess the prevalence of macrolide resistance in Haemophilus spp, across different global regions.

METHODS

A systematic literature search was conducted across PubMed, Embase, Web of Science, and Scopus databases from May 2015 to December 2023 to identify studies on macrolide resistance in Haemophilus spp. The review included English-language full-text articles that reported resistance proportions and sample sizes. Study quality was assessed using the JBI Critical Appraisal Tool. Statistical analysis was performed using a random-effects model using the metafor package in R.

RESULTS

A total of 10,114 articles were retrieved, and after a comprehensive evaluation, 15 studies (from 19 reports) met the eligibility criteria for inclusion in this systematic review and meta-analysis. Most studies (eight reports from three countries) focused on clarithromycin susceptibility, revealing a pooled prevalence of 7.2%. High heterogeneity was observed for azithromycin (I² = 96.31%, p < 0.001). Azithromycin resistance was higher than clarithromycin, with a resistance rate of 9.3% (nine reports), while erythromycin resistance was significantly higher at 79% (four reports). Subgroup analysis revealed significant variations in resistance prevalence based on geographic location and continent for azithromycin, erythromycin, and clarithromycin. Additionally, notable differences were observed in resistance rates depending on antimicrobial susceptibility testing (AST) methods and AST guidelines for both azithromycin and erythromycin. Clarithromycin resistance increased from 0.7% (2015-2019) to 12.6% (2020-2023).

CONCLUSION

The study underscores the significant challenges of macrolide resistance in treating Haemophilus spp. infections. Additionally, ongoing surveillance of resistance patterns and exploring contributing factors are crucial to enhancing treatment effectiveness.

Etiological Characteristics and Risk Factors of Chronic Obstructive Pulmonary Disease Combined with Infection

The distribution characteristics of pathogenic bacteria and the related health risk of pulmonary infection in patients with chronic obstructive pulmonary disease (COPD) were retrospectively analyzed to develop targeted measures to enhance patient prognosis. A retrospective analysis was conducted on the clinical data of 108 patients with COPD complicated with pulmonary infection and 108 patients without pulmonary infection. Analyze the distribution of pathogens in the lung infection group. Perform univariate analysis on the general data of two groups of patients and use multivariate logistic regression analysis to screen for independent risk factors affecting pulmonary infection in COPD patients. The results of univariate analysis showed that the ratio of patients aged ≥ 60 years, complicated with diabetes, duration of hospitalization ≥ 15 days, type of antimicrobial agents ≥ 2, and transforming growth factor-β (TGF-β) and serum tumor necrosis factor-α (TNF-α) in the pulmonary infection group were significantly greater than those in the group without pulmonary infection. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) were significantly lower than in the group without pulmonary infection (P < 0.05). Multivariate Logistic regression analysis showed that unrelated health risks for pulmonary infection in COPD patients were age ≥ 60 years, length of hospitalization ≥ 15 days, combination of diabetes mellitus, and use of ≥ 2 types of antibacterial drugs. Age ≥ 60 years old, hospital stay ≥ 15 days, diabetes patients, and antibacterial drugs ≥ 2 are the risk factors of COPD patients with pulmonary infection.

A 7-point evidence-based care discharge protocol for patients hospitalized for exacerbation of COPD: consensus strategy and expert recommendation

Acute exacerbations of COPD (ECOPD) are an important event in the life of a COPD patient as it causes significant deterioration of physical, mental, and social health, hastens disease progression, increases the risk of dying and causes a huge economic loss. Preventing ECOPD is therefore one of the most important goals in the management of COPD. Before the patient is discharged after hospitalization for ECOPD, it is crucial to offer an evidence-based care bundle protocol that will help minimize the future risk of readmissions and death. To develop the content of this quality care bundle, an Expert Working Group was formed, which performed a systematic review of literature, brainstormed, and debated on key clinical issues before arriving at a consensus strategy that could help physicians achieve this goal. A 7-point consensus strategy was prepared, which included: (1) enhancing awareness and seriousness of ECOPD, (2) identifying patients at risk for future exacerbations, (3) optimizing pharmacologic treatment of COPD, (4) identifying and treating comorbidities, (5) preventing bacterial and viral infections, (6) pulmonary rehabilitation, and (7) palliative care. Physicians may find this 7-point care bundle useful to minimize the risk of future exacerbations and reduce morbidity and mortality.

Molecular characterization of macrolide resistance in Haemophilus influenzae and Haemophilus parainfluenzae strains (2018-21)

OBJECTIVES

This study aimed to explore the prevalence of macrolide resistance and the underlying resistance mechanisms in Haemophilus influenzae (n = 2556) and Haemophilus parainfluenzae (n = 510) collected between 2018 and 2021 from Bellvitge University Hospital, Spain.

METHODS

Antimicrobial susceptibility was tested by microdilution. Whole-genome sequencing was performed using Illumina MiSeq and Oxford Nanopore technologies, and sequences were examined for macrolide resistance determinants and mobile genetic structures.

RESULTS

Macrolide resistance was detected in 67 H. influenzae (2.6%) and 52 (10.2%) H. parainfluenzae strains and associated with resistance to other antimicrobials (co-trimoxazole, chloramphenicol, tetracycline). Differences in macrolide resistance existed between the two species. Acquired resistance genes were more prevalent in H. parainfluenzae (35/52; 67.3%) than in H. influenzae (12/67; 17.9%). Gene mutations and amino acid substitutions were more common in H. influenzae (57/67; 85%) than in H. parainfluenzae (16/52; 30.8%). Substitutions in L22 and in 23S rRNA were only detected in H. influenzae (34.3% and 29.0%, respectively), while substitutions in L4 and AcrAB/AcrR were observed in both species. The MEGA element was identified in 35 (67.3%) H. parainfluenzae strains, five located in an integrative and conjugative element (ICE); by contrast, 11 (16.4%) H. influenzae strains contained the MEGA element (all in an ICE). A new ICEHpaHUB8 was described in H. parainfluenzae.

CONCLUSIONS

Macrolide resistance was higher in H. parainfluenzae than in H. influenzae, with differences in the underlying mechanisms. H. parainfluenzae exhibits co-resistance to other antimicrobials, often leading to an extensively drug-resistant phenotype. This highlights the importance of conducting antimicrobial resistance surveillance.

Time to re-set our thinking about airways disease: lessons from history, the resurgence of chronic bronchitis / PBB and modern concepts in microbiology

In contrast to significant declines in deaths due to lung cancer and cardiac disease in Westernised countries, the mortality due to 'chronic obstructive pulmonary disease' (COPD) has minimally changed in recent decades while 'the incidence of bronchiectasis' is on the rise. The current focus on producing guidelines for these two airway 'diseases' has hindered progress in both treatment and prevention. The elephant in the room is that neither COPD nor bronchiectasis is a disease but rather a consequence of progressive untreated airway inflammation. To make this case, it is important to review the evolution of our understanding of airway disease and how a pathological appearance (bronchiectasis) and an arbitrary physiological marker of impaired airways (COPD) came to be labelled as 'diseases'. Valuable insights into the natural history of airway disease can be obtained from the pre-antibiotic era. The dramatic impacts of antibiotics on the prevalence of significant airway disease, especially in childhood and early adult life, have largely been forgotten and will be revisited as will the misinterpretation of trials undertaken in those with chronic (bacterial) bronchitis. In the past decades, paediatricians have observed a progressive increase in what is termed 'persistent bacterial bronchitis' (PBB). This condition shares all the same characteristics as 'chronic bronchitis', which is prevalent in young children during the pre-antibiotic era. Additionally, the radiological appearance of bronchiectasis is once again becoming more common in children and, more recently, in adults. Adult physicians remain sceptical about the existence of PBB; however, in one study aimed at assessing the efficacy of antibiotics in adults with persistent symptoms, researchers discovered that the majority of patients exhibiting symptoms of PBB were already on long-term macrolides. In recent decades, there has been a growing recognition of the importance of the respiratory microbiome and an understanding of the ability of bacteria to persist in potentially hostile environments through strategies such as biofilms, intracellular communities, and persister bacteria. This is a challenging field that will likely require new approaches to diagnosis and treatment; however, it needs to be embraced if real progress is to be made.

Multimodal evaluation of drug antibacterial activity reveals cinnamaldehyde analog anti-biofilm effects against Haemophilus influenzae

Biofilm formation by the pathobiont Haemophilus influenzae is associated with human nasopharynx colonization, otitis media in children, and chronic respiratory infections in adults suffering from chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD). β-lactam and quinolone antibiotics are commonly used to treat these infections. However, considering the resistance of biofilm-resident bacteria to antibiotic-mediated killing, the use of antibiotics may be insufficient and require being replaced or complemented with novel strategies. Moreover, unlike the standard minimal inhibitory concentration assay used to assess antibacterial activity against planktonic cells, standardization of methods to evaluate anti-biofilm drug activity is limited. In this work, we detail a panel of protocols for systematic analysis of drug antimicrobial effect on bacterial biofilms, customized to evaluate drug effects against H. influenzae biofilms. Testing of two cinnamaldehyde analogs, (E)-trans-2-nonenal and (E)-3-decen-2-one, demonstrated their effectiveness in both H. influenzae inhibition of biofilm formation and eradication or preformed biofilms. Assay complementarity allowed quantifying the dynamics and extent of the inhibitory effects, also observed for ampicillin resistant clinical strains forming biofilms refractory to this antibiotic. Moreover, cinnamaldehyde analog encapsulation into poly(lactic-co-glycolic acid) (PLGA) polymeric nanoparticles allowed drug vehiculization while maintaining efficacy. Overall, we demonstrate the usefulness of cinnamaldehyde analogs against H. influenzae biofilms, present a test panel that can be easily adapted to a wide range of pathogens and drugs, and highlight the benefits of drug nanoencapsulation towards safe controlled release.

Chronic obstructive pulmonary disease and the airway microbiome: A review for clinicians

Chronic obstructive pulmonary disease (COPD) is a complex heterogeneous disease characterized by progressive airflow limitation and chronic inflammation. The progressive development and long-term repeated acute exacerbation of COPD make many patients still unable to control the deterioration of the disease after active treatment, and even eventually lead to death. An increasing number of studies have shown that the occurrence and development of COPD are closely related to the composition and changes of airway microbiome. This article reviews the interaction between COPD and airway microbiome, the potential mechanisms of interaction, and the treatment methods related to microbiome. We elaborated the internal correlation between airway microbiome and different stages of COPD, inflammatory endotypes, glucocorticoid and antibiotic treatment, analyze the pathophysiological mechanisms such as the "vicious cycle" hypothesis, abnormal inflammation-immune response of the host and the "natural selection" of COPD to airway microbiome, introduce the treatment of COPD related to microbiome and emphasize the predictive value of airway microbiome for the progression, exacerbation and prognosis of COPD, as well as the guiding role for clinical management of patients, in order to provide a new perspective for exploring the pathogenesis of COPD, and also provide clues and guidance for finding new treatment targets.

Imipenem heteroresistance but not tolerance in Haemophilus influenzae during chronic lung infection associated with chronic obstructive pulmonary disease

Antibiotic resistance is a major Public Health challenge worldwide. Mechanisms other than resistance are described as contributors to therapeutic failure. These include heteroresistance and tolerance, which escape the standardized procedures used for antibiotic treatment decision-making as they do not involve changes in minimal inhibitory concentration (MIC). Haemophilus influenzae causes chronic respiratory infection and is associated with exacerbations suffered by chronic obstructive pulmonary disease (COPD) patients. Although resistance to imipenem is rare in this bacterial species, heteroresistance has been reported, and antibiotic tolerance cannot be excluded. Moreover, development of antibiotic heteroresistance or tolerance during within-host H. influenzae pathoadaptive evolution is currently unknown. In this study, we assessed imipenem resistance, heteroresistance and tolerance in a previously sequenced longitudinal collection of H. influenzae COPD respiratory isolates. The use of Etest, disc diffusion, population analysis profiling, tolerance disc (TD)-test methods, and susceptibility breakpoint criteria when available, showed a significant proportion of imipenem heteroresistance with differences in terms of degree among strains, absence of imipenem tolerance, and no specific trends among serial and clonally related strains could be established. Analysis of allelic variation in the ftsI, acrA, acrB, and acrR genes rendered a panel of polymorphisms only found in heteroresistant strains, but gene expression and genome-wide analyses did not show clear genetic traits linked to heteroresistance. In summary, a significant proportion of imipenem heteroresistance was observed among H. influenzae strains isolated from COPD respiratory samples over time. These data should be useful for making more accurate clinical recommendations to COPD patients.

Lung Microbiome as a Treatable Trait in Chronic Respiratory Disorders

Once thought to be a sterile environment, it is now established that lungs are populated by various microorganisms that participate in maintaining lung function and play an important role in shaping lung immune surveillance. Although our comprehension of the molecular and metabolic interactions between microbes and lung cells is still in its infancy, any event causing a persistent qualitative or quantitative variation in the composition of lung microbiome, termed "dysbiosis", has been virtually associated with many respiratory diseases. A deep understanding of the composition and function of the "healthy" lung microbiota and how dysbiosis can cause or participate in disease progression will be pivotal in finding specific therapies aimed at preventing diseases and restoring lung function. Here, we review lung microbiome dysbiosis in different lung pathologies and the mechanisms by which these bacteria can cause or contribute to the severity of the disease. Furthermore, we describe how different respiratory disorders can be caused by the same pathogen, and that the real pathogenetic mechanism is not only dependent by the presence and amount of the main pathogen but can be shaped by the interaction it can build with other bacteria, fungi, and viruses present in the lung. Understanding the nature of this bacteria crosstalk could further our understanding of each respiratory disease leading to the development of new therapeutic strategies.

Systemic and functional effects of continuous azithromycin treatment in patients with severe chronic obstructive pulmonary disease and frequent exacerbations

BACKGROUND

Continuous treatment with azithromycin may lead to fewer acute exacerbations of chronic obstructive pulmonary disease (AECOPD), but little is known of its impact on systemic and functional outcomes in real-life settings.

METHODS

This was a multicenter prospective observational study of patients with severe COPD who started treatment with azithromycin. Tests were compared at baseline and after 3 and 12 months of treatment. These included lung function tests, a 6-min walking test (6MWT), and enzyme-linked immunosorbent assays of serum and sputum markers, such as interleukins (IL-6, IL-8, IL-13, IL-5), tumor necrosis factor receptor 2 (TNFR2), and inflammatory markers. Incidence rate ratios (IRR) and their 95% confidence intervals (95% CI) are reported.

RESULTS

Of the 478 eligible patients, the 42 who started azithromycin experienced reductions in AECOPDs (IRR, 0.34; 95% CI, 0.26-0.45) and hospitalizations (IRR, 0.39; 95% CI, 0.28-0.49). Treatment was also associated with significant improvement in the partial arterial pressure of oxygen (9.2 mmHg, 95% CI 1.4-16.9) at 12 months. While TNFR2 was reduced significantly in both serum and sputum samples, IL-13 and IL-6 were only significantly reduced in serum samples. Moreover, an elevated serum and sputum IL-8 level significantly predicted good clinical response to treatment.

CONCLUSION

Continuous azithromycin treatment in a cohort of patients with severe COPD and frequent exacerbations can significantly reduce the number and severity of exacerbations and improve gas exchange. Treatment changes the pattern of microorganism isolates and decreases the inflammatory response. Of note, IL-8 may have utility as a predictor of clinical response to azithromycin treatment.