Antibiotic-Resistant Community-Acquired Bacterial Pneumonia

Impact of the COVID-19 pandemic on Haemophilus influenzae infections in pediatric patients hospitalized with community acquired pneumonia

The COVID-19 pandemic has altered the infection landscape for many pathogens. This retrospective study aimed to compare Haemophilus influenzae (H. influenzae) infections in pediatric CAP patients hospitalized before (2018-2019) and during (2020-2022) the COVID-19 pandemic. We analyzed the clinical epidemiology and antimicrobial resistance (AMR) patterns of H. influenzae from a tertiary hospital in southwest China. A total of 986 pediatric CAP patients with H. influenzae-associated infections were included. Compared to 2018, the positivity rate increased in 2019 but dropped significantly in 2020. Although it rose in the following 2 years, the rate in 2022 remained significantly lower than in 2019. Patients' age during the pandemic was significantly higher than in 2018 and 2019, while gender composition remained similar across both periods. Notably, there were significant changes in co-infections with several respiratory pathogens during the pandemic. Resistance rates of H. influenzae isolates to antibiotics varied, with the highest resistance observed for ampicillin (85.9%) and the lowest for cefotaxime (0.0%). Resistance profiles to various antibiotics underwent dramatic changes during the COVID-19 pandemic. Resistance to amoxicillin-clavulanate, cefaclor, cefuroxime, trimethoprim-sulfamethoxazole, and the proportion of multi-drug resistant (MDR) isolates significantly decreased. Additionally, MDR isolates, alongside isolates resistant to specific drugs, were notably prevalent in ampicillin-resistant and β-lactamase-positive isolates. The number of pediatric CAP patients, H. influenzae infections, and isolates resistant to certain antibiotics exhibited seasonal patterns, peaking in the winter of 2018 and 2019. During the COVID-19 pandemic, sharp decreases were observed in February 2020, and there was no resurgence in December 2022. These findings indicate that the COVID-19 pandemic has significantly altered the infection spectrum of H. influenzae in pediatric CAP patients, as evidenced by shifts in positivity rate, demographic characteristics, respiratory co-infections, AMR patterns, and seasonal trends.

Epidemiological and etiological characteristics of 1266 patients with severe acute respiratory infection in central China, 2018-2020: a retrospective survey

BACKGROUND

Severe acute respiratory infection (SARI), a significant global health concern, imposes a substantial disease burden. In China, there is inadequate data concerning the monitoring of respiratory pathogens, particularly bacteria, among patients with SARI. Therefore, this study aims to delineate the demographic, epidemiological, and aetiological characteristics of hospitalised SARI patients in Central China between 2018 and 2020.

METHODS

Eligible patients with SARI admitted to the First Affiliated Hospital of Zhengzhou University between 1 January 2018 and 31 December 2020 were included in this retrospective study. Within the first 24 h of admission, respiratory (including sputum, nasal/throat swabs, bronchoalveolar lavage fluid, thoracocentesis fluid, etc.), urine, and peripheral blood specimens were collected for viral and bacterial testing. A multiplex real-time polymerase chain reaction (PCR) diagnostic approach was used to identify human influenza virus, respiratory syncytial virus, parainfluenza virus, adenovirus, human bocavirus, human coronavirus, human metapneumovirus, and rhinovirus. Bacterial cultures of respiratory specimens were performed with a particular focus on pathogenic microorganisms, including S. pneumoniae, S. aureus, K. pneumoniae, P. aeruginosa, Strep A, H. influenzae, A. baumannii, and E. coli. In cases where bacterial culture results were negative, nucleic acid extraction was performed for PCR to assay for the above-mentioned eight bacteria, as well as L. pneumophila and M. pneumoniae. Additionally, urine specimens were exclusively used to detect Legionella antigens. Furthermore, epidemiological, demographic, and clinical data were obtained from electronic medical records.

RESULTS

The study encompassed 1266 patients, with a mean age of 54 years, among whom 61.6% (780/1266) were males, 61.4% (778/1266) were farmers, and 88.8% (1124/1266) sought medical treatment in 2020. Moreover, 80.3% (1017/1266) were housed in general wards. The most common respiratory symptoms included fever (86.8%, 1122/1266) and cough (77.8%, 986/1266). Chest imaging anomalies were detected in 62.6% (792/1266) of cases, and 58.1% (736/1266) exhibited at least one respiratory pathogen, with 28.5% (361/1266) having multiple infections. Additionally, 95.7% (1212/1266) of the patients were from Henan Province, with the highest proportion (38.3%, 486/1266) falling in the 61-80 years age bracket, predominantly (79.8%, 1010/1266) seeking medical aid in summer and autumn. Bacterial detection rate (39.0%, 495/1266) was higher than viral detection rate (36.9%, 468/1266), with the primary pathogens being influenza virus (13.8%, 175/1266), K. pneumoniae (10.0%, 127/1266), S. pneumoniae (10.0%, 127/1266), adenovirus (8.2%, 105/1266), P. aeruginosa (8.2%, 105/1266), M. pneumoniae (7.8%, 100/1266), and respiratory syncytial virus (7.7%, 98/1266). During spring and winter, there was a significant prevalence of influenza virus and human coronavirus, contrasting with the dominance of parainfluenza viruses in summer and autumn. Respiratory syncytial virus and rhinovirus exhibited higher prevalence across spring, summer, and winter. P. aeruginosa, K. pneumoniae, and M. pneumoniae were identified at similar rates throughout all seasons without distinct spikes in prevalence. However, S. pneumoniae showed a distinctive pattern with a prevalence that doubled during summer and winter. Moreover, the positive detection rates of various other viruses and bacteria were lower, displaying a comparatively erratic prevalence trend. Among patients admitted to the intensive care unit, the predominant nosocomial bacteria were K. pneumoniae (17.2%, 43/249), A. baumannii (13.6%, 34/249), and P. aeruginosa (12.4%, 31/249). Conversely, in patients from general wards, predominant pathogens included influenza virus (14.8%, 151/1017), S. pneumoniae (10.4%, 106/1017), and adenovirus (9.3%, 95/1017). Additionally, paediatric patients exhibited significantly higher positive detection rates for influenza virus (23.9%, 11/46) and M. pneumoniae (32.6%, 15/46) compared to adults and the elderly. Furthermore, adenovirus (10.0%, 67/669) and rhinovirus (6.4%, 43/669) were the primary pathogens in adults, while K. pneumoniae (11.8%, 65/551) and A. baumannii (7.1%, 39/551) prevailed among the elderly, indicating significant differences among the three age groups.

DISCUSSION

In Central China, among patients with SARI, the prevailing viruses included influenza virus, adenovirus, and respiratory syncytial virus. Among bacteria, K. pneumoniae, S. pneumoniae, P. aeruginosa, and M. pneumoniae were frequently identified, with multiple infections being very common. Additionally, there were substantial variations in the pathogen spectrum compositions concerning wards and age groups among patients. Consequently, this study holds promise in offering insights to the government for developing strategies aimed at preventing and managing respiratory infectious diseases effectively.

Evaluation and clinical practice of pathogens and antimicrobial resistance genes of BioFire FilmArray Pneumonia panel in lower respiratory tract infections

BACKGROUND

Existing panels for lower respiratory tract infections (LRTIs) are slow and lack quantification of important pathogens and antimicrobial resistance, which are not solely responsible for their complex etiology and antibiotic resistance. BioFire FilmArray Pneumonia (PN) panels may provide rapid information on their etiology.

METHODS

The bronchoalveolar lavage fluid of 187 patients with LRTIs was simultaneously analyzed using a PN panel and cultivation, and the impact of the PN panel on clinical practice was assessed. The primary endpoint was to compare the consistency between the PN panel and conventional microbiology in terms of etiology and drug resistance, as well as to explore the clinical significance of the PN panel. The secondary endpoint was pathogen detection using the PN panel in patients with community-acquired pneumonia (CAP) or hospital-acquired pneumonia (HAP).

RESULTS

Fifty-seven patients with HAP and 130 with CAP were included. The most common pathogens of HAP were Acinetobacter baumannii and Klebsiella pneumoniae, with the most prevalent antimicrobial resistance (AMR) genes being CTX-M and KPC. For CAP, the most common pathogens were Haemophilus influenzae and Staphylococcus aureus, with the most frequent AMR genes being CTX-M and VIM. Compared with routine bacterial culture, the PN panel demonstrated an 85% combined positive percent agreement (PPA) and 92% negative percent agreement (NPA) for the qualitative identification of 13 bacterial targets. PN detection of bacteria with higher levels of semi-quantitative bacteria was associated with more positive bacterial cultures. Positive concordance between phenotypic resistance and the presence of corresponding AMR determinants was 85%, with 90% positive agreement between CTX-M-type extended-spectrum beta-lactamase gene type and phenotype and 100% agreement for mecA/C and MREJ. The clinical benefit of the PN panel increased by 25.97% compared with traditional cultural tests.

CONCLUSION

The bacterial pathogens and AMR identified by the PN panel were in good agreement with conventional cultivation, and the clinical benefit of the PN panel increased by 25.97% compared with traditional detection. Therefore, the PN panel is recommended for patients with CAP or HAP who require prompt pathogen diagnosis and resistance identification.

Wastewater treatment plants: The missing link in global One-Health surveillance and management of antibiotic resistance

INTRODUCTION

As a global public health crisis, antibiotic resistance (AR) should be monitored and managed under the One-Health concept according to the World Health Organization (WHO), considering the interconnection between humans, animals, and the environment. But this approach often remains focused on human health and rarely on the environment and its compartments, especially wastewater as the main AR receptor. Wastewater treatment plants (WWTPs) not only are not designed for reliving AR but also provide appropriate conditions for enhancing AR through different mechanisms.

METHODS

By reviewing the research-based statistics on the inclusion of WWTPs in the One-Health/AR program crisis, this paper highlights the importance of paying attention to these hotspots, at first. Also, the importance and technical roadmap for the application of WWTPs in both surveillance and management of AR were provided. The current position of these facilities was also evaluated using strengths, weaknesses, opportunities, and threats (SWOT) analysis. In the end, the concluding knowledge gaps and research needs for future investigations were presented.

RESULTS

Despite the fact that wastewater matrices are the hotspot for AR dissemination, WWTPs appear under-represented in One-Health/AR literature. So, of the 414434 articles retrieved for One-Health only 1.5% (n = 6321) focused on AR and about 0.04% (n = 158) on WWTPs. The potential of WWTPs inclusion in AR surveillance has been confirmed by several studies, however, when it comes to its inclusion for management of AR, more evidence should be presented, which confirmed by SWOT results.

DISCUSSION

As such, WWTPs simultaneously provide opportunities for AR surveillance as it is assumed that this medium can reflect the reality of the corresponding society, and for managing unexpected crises which could impact the public. Nonetheless, there are still numerous considerations to change WWTPs role from Achilles' heel to Ajax' shield, including strengthening the research-based knowledge and conducting both surveillance and management strategies of AR under One-Health concept (One-Health/AR) in a clear straightforward framework.

Crisis averted: a world united against the menace of multiple drug-resistant superbugs -pioneering anti-AMR vaccines, RNA interference, nanomedicine, CRISPR-based antimicrobials, bacteriophage therapies, and clinical artificial intelligence strategies to safeguard global antimicrobial arsenal

The efficacy of antibiotics and other antimicrobial agents in combating bacterial infections faces a grave peril in the form of antimicrobial resistance (AMR), an exceedingly pressing global health issue. The emergence and dissemination of drug-resistant bacteria can be attributed to the rampant overuse and misuse of antibiotics, leading to dire consequences such as organ failure and sepsis. Beyond the realm of individual health, the pervasive specter of AMR casts its ominous shadow upon the economy and society at large, resulting in protracted hospital stays, elevated medical expenditures, and diminished productivity, with particularly dire consequences for vulnerable populations. It is abundantly clear that addressing this ominous threat necessitates a concerted international endeavor encompassing the optimization of antibiotic deployment, the pursuit of novel antimicrobial compounds and therapeutic strategies, the enhancement of surveillance and monitoring of resistant bacterial strains, and the assurance of universal access to efficacious treatments. In the ongoing struggle against this encroaching menace, phage-based therapies, strategically tailored to combat AMR, offer a formidable line of defense. Furthermore, an alluring pathway forward for the development of vaccines lies in the utilization of virus-like particles (VLPs), which have demonstrated their remarkable capacity to elicit a robust immune response against bacterial infections. VLP-based vaccinations, characterized by their absence of genetic material and non-infectious nature, present a markedly safer and more stable alternative to conventional immunization protocols. Encouragingly, preclinical investigations have yielded promising results in the development of VLP vaccines targeting pivotal bacteria implicated in the AMR crisis, including Salmonella, Escherichia coli, and Clostridium difficile. Notwithstanding the undeniable potential of VLP vaccines, formidable challenges persist, including the identification of suitable bacterial markers for vaccination and the formidable prospect of bacterial pathogens evolving mechanisms to thwart the immune response. Nonetheless, the prospect of VLP-based vaccines holds great promise in the relentless fight against AMR, underscoring the need for sustained research and development endeavors. In the quest to marshal more potent defenses against AMR and to pave the way for visionary innovations, cutting-edge techniques that incorporate RNA interference, nanomedicine, and the integration of artificial intelligence are currently under rigorous scrutiny.

Application of Multiplex Fluorescence Polymerase Chain Reaction for Detecting Pathogenic Bacteria in Sputum Samples from Patients with Lower Respiratory Tract Infection

Objective

In this study, we conducted a multi-center research on six common lower respiratory tract pathogens using novel multiplex fluorescence quantitative polymerase chain reaction (PCR), and investigated the additional diagnostic value of this method, to provide a molecular diagnostic basis for clinical practice.

Methods

From March 2019 to October 2021, a total of 2047 respiratory sputum samples were collected from Hunan Provincial People's Hospital (the First Affiliated Hospital of Hunan Normal University), Hunan Provincial Children's Hospital, Jiangxi Provincial Children's Hospital, and Wuhan Infectious Disease Hospital. The samples were analyzed using a novel multiplex fluorescence quantitative PCR method for Klebsiella pneumoniae, Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas aeruginosa, Legionella pneumophila, and Staphylococcus aureus. The results were compared to the results of bacterial culture and sequencing, as well as the results of third-party kits.

Results

Compared to the bacterial culture method, 2047 samples were detected with a sensitivity of 100%, a specificity of 72.22%, and an overall compliance rate of 81.91%. Compared to the sequencing method, the positive agreement percentage was 99.88%, the negative agreement percentage was 97.72%, and the overall agreement rate was 98.84%. Compared to similar control reagents, the positive agreement percentage was 100%, negative agreement percentage was 79.79%, and overall compliance rate was 96.19%.

Conclusion

The multiplex fluorescence PCR method has the advantages of simultaneously detecting multiple pathogenic bacteria and reducing the duration of pathogen culture identification. Combined detection can increase the detection rate, which has favorable performance and application prospects.

Bibliometric Analysis of Global Research Output on Antimicrobial Resistance among Pneumonia Pathogens (2013-2023)

Antimicrobial resistance (AMR) is a pressing global concern, posing significant challenges to the effective treatment of infections, including pneumonia. This bibliometric analysis aims to investigate the research output on AMR among pneumonia pathogens from 2013 to 2023. Data were extracted from the Web of Science Core Collection (WOS-CC) using an inclusive search strategy. The analysis included 152 relevant studies published in 99 different sources, involving 988 authors and yielding an average of 16.33 citations per document over the past decade. The findings reveal a notable increase in research on AMR among pneumonia pathogens, indicating a growing awareness of this critical issue. Collaborative studies were prevalent, with the majority of authors engaging in joint research efforts. Bradford's Law identified twelve core journals that were instrumental in disseminating research in this field, with "Medicine" emerging as the most prolific journal. The USA and China emerged as the leading contributors, while Germany displayed a strong inclination towards collaborative research. Intermountain Medical Center, Saitama Medical University, and Udice-French Research Universities were the most productive institutions, and Yayan J. and Rasche K. were the top authors. Furthermore, the analysis identified commonly encountered microorganisms such as Acinetobacter baumanii and Klebsiella pneumoniae in the context of AMR. Time-based analysis of keywords highlighted the significance of terms like "community-acquired pneumonia" and "ventilator-associated pneumonia". Overall, this comprehensive study sheds light on the global research landscape of AMR among pneumonia pathogens. The insights gained from this analysis are essential for guiding future research priorities and collaborative efforts to combat AMR effectively and improve treatment outcomes for pneumonia and related infections. As the frequency of reports concerning resistance among pneumonia pathogens, notably A. baumannii and K. pneumoniae, continues to rise, there is an immediate requirement for pharmaceutical manufacturers and healthcare providers to respond proactively and ready themselves for the forthcoming implications of this matter. It also underscores the importance of knowledge dissemination and evidence-based interventions to address this growing public health challenge. However, the study acknowledges the limitations associated with using a single publication database and encourages the inclusion of data from other sources in future research.

An Insight into the Exploration of Antibiotic Resistance Genes in Calorie Restricted Diet Fed Mice

Antibiotic resistance genes (ARGs) threaten the success of modern drugs against multidrug resistant infections. ARGs can be transferred to opportunistic pathogens by horizontal gene transfer (HGT). Many studies have investigated the characteristics of ARGs in various chemical stressors. Studies on the effects of dietary nutrition and dietary patterns on ARGs are rare. The study first demonstrated the effect of calorie restricted (CR) diet on the ARGs and mobile genetic elements (MGEs) in mouse feces and explored their relationship with gut microbiota and their functions. The results showed that the abundance of the total ARGs in mouse feces of the CR group increased, especially tetracycline ARGs (tetW-01). The abundance of the MLSB ARGs (ermB) decreased evidently in mouse feces of the CR group. In addition, the total abundance of MGEs decreased evidently in the CR group, especially tnpA-03. In the meantime, the abundance of Lactobacillus and Bifidobacterium in mouse feces of the CR group increased remarkably. The Spearman correlation analysis between gut microbiota and ARGs showed that several probiotics were significantly positively correlated with ARGs (tetW-01), which might be the main contribution to the increase in ARGs of the CR group.

Gaps in the wall: understanding cell wall biology to tackle amoxicillin resistance in Streptococcus pneumoniae

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia, and one of the main pathogens responsible for otitis media infections in children. Amoxicillin (AMX) is a broad-spectrum β-lactam antibiotic, used frequently for the treatment of bacterial respiratory tract infections. Here, we discuss the pneumococcal response to AMX, including the mode of action of AMX, the effects on autolysin regulation, and the evolution of resistance through natural transformation. We discuss current knowledge gaps in the synthesis and translocation of peptidoglycan and teichoic acids, major constituents of the pneumococcal cell wall and critical to AMX activity. Furthermore, an outlook of AMX resistance research is presented, including the development of natural competence inhibitors to block evolution via horizontal gene transfer, and the use of high-throughput essentiality screens for the discovery of novel cotherapeutics.

Protective role of FBXL19 in Streptococcus pneumoniae-induced lung injury in pneumonia immature mice

OBJECTIVE

Streptococcus pneumoniae (Spn) is a common pathogen for pediatric pneumonia and leads to severe lung injury. This study is conducted to analyze the role of F-box and leucine rich repeat protein 19 (FBXL19) in Spn-induced lung injury in immature mice.

METHODS

Immature mice were infected with Spn to record the survival rates and bacterial loads in bronchoalveolar lavage fluid. Levels of FBXL19 and FOXM1 in lung tissues were determined via real-time quantitative polymerase chain reaction or Western blotting. After the interference of FBXL19, its impacts on lung inflammatory injury were appraised by the lung wet/dry weight ratio, myeloperoxidase activity, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay. The binding of FBXL19 to forkhead box M1 (FOXM1) in mouse lung epithelial cells was determined. After MG132 treatment, the protein and ubiquitination levels of FOXM1 were measured. The functional rescue experiments were performed to analyze the role of FOXM1 in FBXL19-regulated lung injury.

RESULTS

FBXL19 was downregulated while FOXM1 was upregulated in lung tissues of Spn-infected immature mice. Overexpression of FBXL19 reduced the degree of lung injury and inflammation. FBXL19 can bind to FOXM1 to reduce its protein level via ubiquitination degradation. MG132 reduced the ubiquitination and increased the protein level of FOXM1. Overexpression of FOXM1 reversed the protective role of FBXL19 overexpression in lung injury of Spn immature mice.

CONCLUSION

FBXL19 was downregulated by Spn and FBXL19 overexpression alleviated lung injury by inducing ubiquitination and degradation of FOXM1 in Spn immature mice.

Qiangli Wuhu mixture alleviates LPS-induced pneumonia by inhibiting the TLR4/NF-κB/NLRP3 pathway: a study based on network pharmacology

CONTEXT

Qiangli Wuhu (QLWH) mixture is a concoction approved and registered by Ningxia Medical Products Administration. It has therapeutic effects on various types of pneumonia.

OBJECTIVE

To clarify the mechanisms of QLWH in treating pneumonia.

MATERIALS AND METHODS

The potential targets of QLWH in the treatment of pneumonia were predicted by network pharmacology. Male, Institute of Cancer Research (ICR) mice were randomly divided into five groups of 12 mice, control, vehicle, QLWH (10 and 20 mg/kg) and dexamethasone (DXM), and orally treated twice daily with normal saline, QLWH or DXM. The pneumonia model was established by tracheal instillation of lipopolysaccharide (LPS). After treatment five days, ELISA, H&E staining and Western blot were used to investigate protective effects of QLWH.

RESULTS

Nine hundred and ninety-four active ingredients were found through network pharmacology, corresponding to 135 targets for the treatment of pneumonia; compared to the vehicle group, QLWH (10 and 20 mg/kg) significantly decreased the levels of TNF-α (14.3% and 28.8%), IL-1β (23.9% and 42.8%) and IL-6 (13.2% and 16.1%), increased the levels of IL-10 (134.3% and 172.9%); in terms of mechanism, QLWH down-regulated TLR4/NF-κB/NLRP3 axis related proteins in lung tissue of pneumonia model mice (p < 0.05).

DISCUSSION AND CONCLUSIONS

This study combined network pharmacology and animal experiments, providing effective evidence for the clinical promotion of QLWH. Meanwhile, it is of significance for further development.

The current landscape of microRNAs (miRNAs) in bacterial pneumonia: opportunities and challenges

MicroRNAs (miRNAs), which were initially discovered in Caenorhabditis elegans, can regulate gene expression by recognizing cognate sequences and interfering with the transcriptional or translational machinery. The application of bioinformatics tools for structural analysis and target prediction has largely driven the investigation of certain miRNAs. Notably, it has been found that certain miRNAs which are widely involved in the inflammatory response and immune regulation are closely associated with the occurrence, development, and outcome of bacterial pneumonia. It has been shown that certain miRNA techniques can be used to identify related targets and explore associated signal transduction pathways. This enhances the understanding of bacterial pneumonia, notably for “refractory” or drug-resistant bacterial pneumonia. Although these miRNA-based methods may provide a basis for the clinical diagnosis and treatment of this disease, they still face various challenges, such as low sensitivity, poor specificity, low silencing efficiency, off-target effects, and toxic reactions. The opportunities and challenges of these methods have been completely reviewed, notably in bacterial pneumonia. With the continuous improvement of the current technology, the miRNA-based methods may surmount the aforementioned limitations, providing promising support for the clinical diagnosis and treatment of “refractory” or drug-resistant bacterial pneumonia.

Prokineticin 2 promotes macrophages-mediated antibacterial host defense against bacterial pneumonia

OBJECTIVES

Bacterial pneumonia is a common serious infectious disease with high morbidity and mortality. Prokineticin 2 (PK2) has recently been identified as a novel immunomodulator in a variety of diseases; however, its role in bacterial pneumonia remains unclear.

METHODS

The levels of PK2 were measured and analyzed in patients with pneumonia and healthy controls. The effects of PK2 on the host response to pneumonia were evaluated by in vivo animal experiments and in vitro cell experiments.

RESULTS

PK2 levels dramatically decreased in patients with pneumonia compared with healthy controls, and PK2 levels were lower in patients with severe pneumonia than in pneumonia. In a mouse model of bacterial pneumonia, transtracheal administration of recombinant PK2 significantly alleviated lung injury and improved the survival, which was associated with increased host's bacterial clearance capacity, as manifested by decreased pulmonary bacterial loads. PK2 enhanced the chemotaxis, phagocytosis, and killing ability of macrophages, whereas the protective efficacy of PK2 was abolished after macrophage depletion.

CONCLUSION

Impaired alveolar macrophage function caused by decreased PK2 is a new endogenous cause of the occurrence and development of bacterial pneumonia. The administration of recombinant PK2 may be a potential adjuvant therapy for bacterial pneumonia.

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

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

Antimicrobial Resistance Trends of the Most Common Causative Pathogens Associated with Community-acquired Respiratory Infections in China: 2009–2018

Background

Emergence of antimicrobial resistance poses new challenges in the management of community acquired respiratory tract infections (CARTIs). Therefore, surveillance on the antimicrobial susceptibilities of common respiratory pathogens is valuable and guides empirical therapeutic choices in management of CARTIs.

Objective

The objective of the current study is to summarize the antimicrobial resistance trends in common respiratory tract pathogens isolated from patients with CARTIs in China, over a 10-year period (2009–2018).

Methods

Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis strains were collected from multicenter, and antimicrobial susceptibility testing was performed in the research central laboratory of each study period from 2009–2018. The pathogens that accounted for CARTIs in the adult population was considered and summarized.

Results

From 2009–2018 a total of 3750 isolates were collected from 22 cities located across different regions of China. Among these the most common bacterial isolates include S. pneumoniae (53.7%) followed by H. influenza (32.4%), M. catarrhalis (13.9%). S. pneumoniae exhibited reduction in susceptibility and increase in resistance to penicillin, cephalosporins (cefaclor, cefuroxime, ceftriaxone) during the surveillance period. Invasive and noninvasive S. pneumoniae showed similar resistance. In the case of H. influenzae susceptibility to β-lactam and β-lactamase inhibitors (ampicillin, amoxicillin and AMC), SXT, clarithromycin and cephalosporins (cefuroxime, cefaclor, ceftazidime) was reduced over the past 10 years with an exception of ceftriaxone. Overall, moxifloxacin and levofloxacin have the highest susceptibility rates against S. pneumoniae (>95%) and H. influenza (>90%). M. catarrhalis exhibited susceptibility to almost all the tested antimicrobials.

Conclusion

In China the 10-year trends showed a substantial increase in resistance to β-lactam drugs and reduction in sensitivity. However, certain antimicrobial agents namely fluoroquinolones including moxifloxacin and levofloxacin maintained low resistance rates with better susceptibility. Further, with few exceptions decline in susceptibility rates to macrolides and cephalosporins was observed among the tested pathogens.

Ceftriaxone resistance and adequacy of initial antibiotic therapy in community onset bacterial pneumonia

Much remains unknown about the impact of initial antibiotic adequacy on mortality in community onset bacterial pneumonia (COBP). Therefore, we performed a study to determine how the adequacy of initial antibiotic therapy affects in-hospital mortality for patients with COBP.We carried out a retrospective cohort study among the 11 BJC Healthcare community and academic hospitals in Missouri and Illinois. The electronic medical records for BJC Healthcare were queried to obtain a set of patient admissions with culture positive (respiratory or blood) COBP admitted from January 1, 2016 through December 31, 2019. Patients with COBP required an International Classification of Diseases (ICD)-10 diagnostic code for pneumonia, admission to the hospital through an emergency department, a chest radiograph with an infiltrate, an abnormal white blood cell count or temperature, an order for 1 or more new antibiotics, and a positive respiratory or blood culture. Antibiotic selection was deemed adequate if the patient had organisms susceptible to at least one of the antibiotics received according to in vitro testing using standard laboratory breakpoints.Among 36,645 screened pneumonia admissions, 1843 met criteria for culture positive COBP. Eight hundred nineteen (44.4%) had ceftriaxone-resistant (CTX-R) organisms and 1024 had ceftriaxone-sensitive (CTX-S) organisms. The most common CTX-R pathogens were methicillin resistant Staphylococcus aureus (46.9%), Pseudomonas species (38.4%), and Escherichia coli (4.5%). On the day of admission 71% of all patients were given adequate antibiotic treatment (62.2% of CTX-R and 77.9% of CTX-S). Unnecessarily broad initial treatment was administered to 57.1% of CTX-S patients. In a logistic regression model accounting for comorbidities and severity of illness, inadequate therapy on the day of admission was associated with higher in-hospital mortality (P = .005). Among CTX-S patients who were adequately treated, initial use of unnecessarily broad antibiotics was associated with increased in-hospital mortality (P = .003).Ceftriaxone resistance was common in this cohort of culture positive COBP patients. Inappropriate coverage on day of admission was associated with greater likelihood of in-hospital mortality.

Intrapleural injection of urokinase in the treatment of acute Haemophilus influenza empyema in children: A case report and literature review

OBJECTIVE

The purpose of this study is to analyze the clinical data of a child with acute empyema caused by Haemophilus influenzae, and to investigate the diagnosis and treatment of this disease through literature review to improve the clinical understanding of this kind of disease.

METHODS

A 6-year-old female with acute H. influenzae empyema was treated at the Department of Pediatrics of The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China. The pleural puncture fluid turned out to be yellow turbid pus, and the pleural effusion was diagnosed as empyema according to the classification of pleural effusions. High-throughput sequencing revealed the presence of H. influenzae. After comprehensive treatment, including antibiotics, closed pleural drainage, and intrapleural injection of urokinase, the pleural effusion was absorbed and discharged. A systematic literature search in Pubmed, Embase, Scopus, CNKI, Wanfang, and VIP Chinese databases revealed no cases of acute empyema in children caused by H. influenza and treated with urokinase.

RESULTS

There was no bronchopleural fistula and tension pneumothorax during the treatment. One month after discharge, chest computed tomography (CT) revealed no pleural thickening and normal pulmonary function.

CONCLUSION

Pneumonia in the child worsened after an initial improvement of symptoms, which is an issue that requires further medical attention. High-throughput sequencing of pathogens in pleural effusion can improve the detection rate. This study indicated that closed pleural drainage combined with intrapleural injection of urokinase is an effective treatment for H. influenzae empyema in children.

Protective effects of Re-yan-ning mixture on Streptococcus pneumonia in rats based on network pharmacology

CONTEXT

Re-yan-ning mixture (RYNM) is a new national drug approved by China's State Food and Drug Administration for the treatment of colds, simple pneumonia and acute bronchitis.

OBJECTIVE

To determine the mechanism of action of RYNM in the treatment of bacterial pneumonia.

MATERIALS AND METHODS

Using the network pharmacology approach, the multiple components, component candidate targets and multiple therapeutic targets of RYNM were screened and functionally enriched. Also, we established a rat Streptococcus pneumonia model to verify the results of network pharmacology enrichment analysis. Forty male SPF Sprague Dawley rats were divided into four groups of 10 rats: control (normal saline), model (normal saline), levofloxacin-intervened and RYNM-intervened groups. IL-10, NOS2, COX-1, IL-6, TNF-α and NF-κB in serum and BALF were detected by ELISA. Western blot detected IL-17, IL-6, TNF-α, COX-2 and Bcl-2.

RESULTS

The network pharmacology approach successfully identified 48 bioactive components in RYNM, and 65 potential targets and 138 signal pathways involved in the treatment of Streptococcus pneumonia with RYNM. The in vivo experiments indicated that model group has visible inflammation and lesions while RYNM and levofloxacin groups have not. The RYNM exhibited its therapeutic effects on Streptococcus pneumonia mainly via the regulation of cell proliferation and survival through the IL-6/IL-10/IL-17, Bax/Bcl-2, COX-1/COX-2, NF-κB and TNF-α signalling pathways.

DISCUSSION AND CONCLUSIONS

The present study demonstrated the protective effects of RYNM on Streptococcus pneumonia, providing a potential mechanism for the treatment of bacterial pneumonia with RYNM.

Pooled Microbiological Findings and Efficacy Outcomes by Pathogen in Adults With Community-Acquired Bacterial Pneumonia from the Lefamulin Evaluation Against Pneumonia (LEAP) 1 and LEAP 2 Phase 3 Trials of Lefamulin Versus Moxifloxacin

BACKGROUND

Lefamulin, a pleuromutilin antibiotic approved for community-acquired bacterial pneumonia (CABP), was evaluated for microbiological efficacy in a prespecified pooled analysis of LEAP 1 and 2 phase 3 clinical trial data in patients with CABP.

METHODS

In LEAP 1, adults (Pneumonia Outcomes Research Team [PORT] risk class III‒V) received intravenous (IV) lefamulin 150 mg every 12 hours (q12h; 5‒7 days) or moxifloxacin 400 mg every 24 hours (q24h; 7 days), with optional IV-to-oral switch. In LEAP 2, adults (PORT II‒IV) received oral lefamulin 600 mg q12h (5 days) or moxifloxacin 400 mg q24h (7 days). Primary outcomes were early clinical response (ECR) 96±24 hours after treatment start and investigator assessment of clinical response (IACR) 5‒10 days after last dose. Secondary outcomes included ECR and IACR in patients with a baseline CABP pathogen (detected via culture, urinary antigen test, serology, and/or real-time PCR).

RESULTS

Baseline CABP pathogens were detected in 709/1289 patients (55.0% [microbiological intent-to-treat population]). The most frequently identified pathogens in this population were Streptococcus pneumoniae (61.9% of patients) and Haemophilus influenzae (29.9%); 25.1% had atypical pathogens and 33.1% had polymicrobial infections. Pathogens were identified most frequently by PCR from sputum, followed by culture from respiratory specimens. In patients with baseline CABP pathogens, ECR rates were 89.3% (lefamulin) and 93.0% (moxifloxacin); IACR success rates were 83.2% and 86.7%, respectively. Results were consistent across CABP pathogens, including drug-resistant isolates and polymicrobial infections.

CONCLUSIONS

Lefamulin is a valuable IV and oral monotherapy option for empiric and directed CABP treatment in adults.

Systematic Study on a Quantitative Analysis of Multicomponents by Single Marker (QAMS) Method for Simultaneous Determination of Eight Constituents in Pneumonia Mixture by UPLC-MS/MS

Pneumonia mixture was formulated and is available to treat children acute pneumonia and acute bronchitis in our hospital for nearly forty years, but there are few studies of its quality evaluation or control. In this paper, a new strategy for quality evaluation of pneumonia mixture was explored and verified through qualitative and quantitative analyses of multicomponents by single marker (QAMS) by UPLC-MS/MS. Baicalein was selected as an internal reference, and the relative correction factors (RCFs) and the relative retention time (RRT) of (R, S)-goitrin, amygdalin, chlorogenic acid, pseudoephedrine hydrochloride, ephedrine hydrochloride, ammonium glycyrrhizinate, and baicalin were established. The robustness and durability of the QAMS method were investigated. RCF values calculated by the average (AVG) method and linear regression (LRG) method had good repeatability and were acceptable for quantitative analysis, and the RTT combined with the exact masses of precursor and fragment ions and their abundance could be adopted for accurately positioning the chromatographic peak of the eight constituents. The consistency and feasibility of the QAMS method were verified by comparing the contents of the seven components calculated by a classic and validated external standard method (ESM) with those of the QAMS method, which reduces analytical cost and time of detection and avoids the problem of the diversity and large quantity of reference standards. The results demonstrated that the QAMS method developed in this paper could provide a new, alternative, and promising method to comprehensively and effectively determine multicomponents and control the quality of pneumonia mixture or even a group of similar medicines.

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.

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.

[Current microbiological aspects of community respiratory infection beyond COVID-19]

From a microbiological point of view, both empirical and targeted antimicrobial treatment in respiratory infection is based on the sensitivity profile of isolated microorganisms and the possible resistance mechanisms that they may present. The latter may vary in different geographic areas according to prescription profiles and vaccination programs. Beta-lactam antibiotics, fluoroquinolones, and macrolides are the most commonly used antimicrobials during the exacerbations of chronic obstructive pulmonary disease and community-acquired pneumonia. In their prescription, different aspects such as intrinsic activity, bactericidal effect or their ability to prevent the development of resistance must be taken into account. The latter is related to the PK/PD parameters, the mutant prevention concentration and the so-called selection window. More recently, the potential ecological impact has grown in importance, not only on the intestinal microbiota, but also on the respiratory one. Maintaining the state of eubiosis requires the use of antimicrobials with a low profile of action on anaerobic bacteria. With their use, the resilience of the bacterial populations belonging to the microbiota, the state of resistance of colonization and the collateral damage related to the emergence of resistance to the antimicrobials in pathogens causing the infections and in the bacterial populations integrating the microbiota.

Effect of the Short-Term Use of Fluoroquinolone and β-Lactam Antibiotics on Mouse Gut Microbiota

BACKGROUND

Antibiotics play an important role in the treatment of infectious diseases. However, the overuse of antibiotics increases the spread of drug-resistant bacteria and causes dysbiosis of the intestinal microbiota. Few studies have addressed the longitudinal effects of antibiotics on the microbiome and host immunity.

MATERIALS AND METHODS

In this study, the short-term effect of fluoroquinolone (levofloxacin) and β-lactam antibiotics (meropenem, cefoperazone/sulbactam, and aztreonam) on the gut microbiota of mice was evaluated by 16S rRNA gene sequencing. The susceptibility of Bifidobacterium longum, Lactobacillus lactis, Enterococcus faecium, and Clostridium butyricum to these antimicrobial agents was assessed using the disc diffusion method.

RESULTS

Our results showed that 4-day antibiotic exposure significantly reduced the alpha and beta diversity of gut bacteria and increased serum inflammatory cytokines, and these changes persisted long after antibiotic withdrawal and did not return to pre-treatment levels. Nonetheless, the bacterial community composition tended to return to pre-treatment levels after discontinuing treatment. The tested probiotic strains were resistant to aztreonam but were sensitive to meropenem and cefoperazone/sulbactam.

CONCLUSION

Short-term antibiotic treatment led to significant changes in the intestinal flora with a tendency to recover. The antibiotics had different effects on the intestinal microbial community and probiotic strains. This study provides guidance for the concomitant use of probiotics and antibiotics, and the results emphasize the importance of using broad-spectrum antibiotics responsibly to prevent the long-term disruption of the native microbiota.

High ratio of C-reactive protein/procalcitonin predicts Mycoplasma pneumoniae infection among adults hospitalized with community acquired pneumonia

There is limited data on serum biomarkers in distinguishing Mycoplasma pneumoniae (MP) from Streptococcus pneumoniae (SP) and viral pneumoniae (VP) etiologies of community-acquired pneumonia (CAP). A retrospective study of inpatients diagnosed with CAP at the First Affiliated Hospital of Dali University (Dali, Yunnan, China) between January 2018 and June 2020 was conducted. The demographic, clinical and laboratory data of the patients with CAP were analyzed. Univariate analyses identified predictors for MP infections. The discriminative power of C-reactive protein (CRP), procalcitonin (PCT), CRP/PCT and CRP/PCT >350 μg/ng was assessed by area under the curve (AUC) of the receiver operating characteristic (ROC) curves. A total of 552 CAP patients, including 247 (44.7%) with MP, 152 (27.6%) with SP and 153 (27.7%) with influenza A and B viruses, were enrolled. When comparing MP with SP, cough and CRP/PCT >350 μg/ng (odds ratio [OR]) 2.88, p < .001) were predictors for MP. CRP/PCT >350 μg/ng had 76% sensitivity and 100% specificity (AUC = 0.89, p < .001, 95% confidence interval [CI]:0.81-0.94) to predict MP infections. Furthermore, similar results were again obtained when comparing MP with VP. CRP/PCT >350 μg/ng present better information (OR: 4.70; AUC = 0.92, p < .001, 87% sensitivity and 100% specificity). In addition, comparing MP and non-MP (SP and VP combined), CRP/PCT >350 μg/ng exhibited excellent performance (AUC = 0.90, 95%CI 0.83-0.95, p < .001, 76% sensitivity and 100% specificity). CRP/PCT ratio may be a potential index to distinguish MP-CAP from non-MP-CAP.

Lefamulin: A Novel Semisynthetic Pleuromutilin Antibiotic for Community-acquired Bacterial Pneumonia

Community-acquired bacterial pneumonia (CABP) remains a significant cause of morbidity and mortality worldwide. Antimicrobial resistance, including in pathogens that cause CABP, continues to spread at an alarming rate. Because of these factors, the development of new antibiotic classes is urgently needed. Lefamulin, previously known as BC-3781, is a semisynthetic pleuromutilin antibiotic that was approved by the Food and Drug Administration for the treatment of CABP in adults. Available in both oral and intravenous formulations, lefamulin has potent in vitro activity against both typical and atypical CABP pathogens. The first pleuromutilin to be used systemically in humans, lefamulin has a unique mechanism of action that inhibits protein synthesis by preventing the binding of tRNA for peptide transfer. This review summarizes the available data on lefamulin, including recent evidence from 2 phase III clinical trials (LEAP 1 and LEAP 2), and discusses its potential role in the treatment of CABP.

Genetic and Functional Diversity of Pseudomonas aeruginosa in Patients With Chronic Obstructive Pulmonary Disease

Pseudomonas aeruginosa is the most relevant pathogen to the severe exacerbations of patients with chronic obstructive pulmonary disease (COPD). However, the genetic and functional characteristics of P. aeruginosa isolates from COPD airways still remain less understood. In this study, the genetic, phylogenetic, phenotypic, and transcriptional features of P. aeruginosa isolates from COPD sputa were comprehensively explored by susceptibility testing, comparative-genomic analysis, phylogenetic analysis, phenotypic profiling, and comparative-transcriptomic analysis. We found that P. aeruginosa was prevalent in elder COPD patients and highly resisted to many commonly used antibiotics. P. aeruginosa COPD isolates harbored a substantial number of variant sites that might influence the primary metabolism and substance transport system. These isolates were discretely distributed in the phylogenetic tree and clustered with internationally collected P. aeruginosa in two major groups, and could be classified into three groups according to their differences in virulence-related phenotypes. Furthermore, the transcriptional patterns of COPD isolates could be classified into PAO1-like group with reduced protein secretion and motility and PAO1-distinct group with decreased substance transport but enhanced primary metabolism. In conclusion, this study demonstrates that P. aeruginosa isolates from COPD patients have abundant genetic and phenotypic diversity, and provides an important reference for further exploring the survival strategy of P. aeruginosa in COPD airways and the development of anti-pseudomonal therapy.

Reversal of heavy metal-induced antibiotic resistance by dandelion root extracts and taraxasterol

Introduction. Metal exposure is an important factor for inducing antibiotic resistance in bacteria. Dandelion extracts have been used for centuries in traditional Chinese and Native American medicine.

Aim. We assessed the effects of dandelion water extracts and taraxasterol on heavy metal-induced antibiotic resistance in Escherichia coli as well as the underlying mechanisms.

Methodology. Dandelion extracts were obtained through 4 h of boiling in distilled water. Bacterial growth was monitored with a spectrophotometer. Biochemical assays were performed to assess the activities and gene transcriptions of β-lactamase and acetyltransferase. Oxidative stress was determined using an oxidation-sensitive probe, H2DCFDA.

Results. The present study demonstrated that higher concentrations of nickel (>5 µg ml−1), cadmium (>0.1 µg ml−1), arsenic (>0.1 µg ml−1) and copper (>5 µg ml−1) significantly inhibited the growth of E. coli . Lower concentrations of nickel (0.5 µg ml−1), cadmium (0.05 µg ml−1) and arsenic (0.05 µg ml−1) had no effect on bacterial growth, but helped the bacteria become resistant to two antibiotics, kanamycin and ampicillin. The addition of dandelion root extracts and taraxasterol significantly reversed the antibiotic resistance induced by these heavy metals. The supplements of antibiotics and cadmium generated synergistic effects on the activities of β-lactamase and acetyltransferase (two antibiotic resistance-related proteins), which were significantly blocked by either dandelion root extract or taraxasterol. In contrast, oxidative stress was not involved in the preventative roles of dandelion root extracts and taraxasterol in heavy metal-induced antibiotic resistance.

Conclusion. This study suggests that heavy metals induce bacterial antibiotic resistance and dandelion root extracts and taraxasterol could be used to help reverse bacterial resistance to antibiotics.

Risk Factors of Multidrug-Resistant Bacteria in Lower Respiratory Tract Infections: A Systematic Review and Meta-Analysis

Background

Multidrug-resistant (MDR) bacteria are the main cause of lower respiratory tract infections (LRTIs) with high mortality. The purpose of this study is to identify the risk factors associated with MDR by performing a systematic review and meta-analysis.

Methods

PubMed, EMBASE (via Ovid), and Cochrane Library were systematically searched for studies on the risk factors for MDR bacteria in LRTIs as of November 30, 2019. Literature screening, data abstraction, and quality assessment of the eligible studies were performed independently by two researchers.

Results

A total of 3,607 articles were retrieved, of which 21 articles representing 20 cohort studies published in English were included after title/abstract and full-text screening. Among the 21 articles involving 7,650 patients and 1,360 MDR organisms, ten reported the risk factors for MDR Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), ten for MDR GNB, and one for MDR GPB. The meta-analysis results suggested that prior antibiotic treatment, inappropriate antibiotic therapy, chronic lung disease, chronic liver disease and cerebral disease, prior MDR and PA infection/colonization, recent hospitalization, longer hospitalization stay, endotracheal tracheostomy and mechanical ventilation, tube feeding, nursing home residence, and higher disease severity score were independent risk factors for MDR bacteria.

Conclusions

This review identified fourteen clinical factors that might increase the risk of MDR bacteria in patients with LRTIs. Clinicians could take into account these factors when selecting antibiotics for patients and determine whether coverage for MDR bacteria is required. More well-designed studies are needed to confirm the various risk factors for MDR bacteria in the future.

Target the Host, Kill the Bug; Targeting Host Respiratory Immunosuppressive Responses as a Novel Strategy to Improve Bacterial Clearance During Lung Infection

The lung is under constant pressure to protect the body from invading bacteria. An effective inflammatory immune response must be tightly orchestrated to ensure complete clearance of any invading bacteria, while simultaneously ensuring that inflammation is kept under strict control to preserve lung viability. Chronic bacterial lung infections are seen as a major threat to human life with the treatment of these infections becoming more arduous as the prevalence of antibiotic resistance becomes increasingly commonplace. In order to survive within the lung bacteria target the host immune system to prevent eradication. Many bacteria directly target inflammatory cells and cytokines to impair inflammatory responses. However, bacteria also have the capacity to take advantage of and strongly promote anti-inflammatory immune responses in the host lung to inhibit local pro-inflammatory responses that are critical to bacterial elimination. Host cells such as T regulatory cells and myeloid-derived suppressor cells are often enhanced in number and activity during chronic pulmonary infection. By increasing suppressive cell populations and cytokines, bacteria promote a permissive environment suitable for their prolonged survival. This review will explore the anti-inflammatory aspects of the lung immune system that are targeted by bacteria and how bacterial-induced immunosuppression could be inhibited through the use of host-directed therapies to improve treatment options for chronic lung infections.