Bacterial Pneumonia Caused by Streptococcus pyogenes Infection: A Case Report and Review of the Literature

Pro-inflammatory interactions of streptolysin O toxin with human neutrophils in vitro

The recent global resurgence of severe infections caused by the Group A streptococcus (GAS) pathogen, Streptococcus pyogenes, has focused attention on this microbial pathogen, which produces an array of virulence factors, such as the pore-forming toxin, streptolysin O (SOT). Importantly, the interactions of SOT with human neutrophils (PMN), are not well understood. The current study was designed to investigate the effects of pretreatment of isolated human PMN with purified SOT on several pro-inflammatory activities, including generation of reactive oxygen species (ROS), degranulation (elastase release), influx of extracellular calcium (Ca2+) and release of extracellular DNA (NETosis), using chemiluminescence, spectrophotometric and fluorimetric procedures, respectively. Exposure of PMN to SOT alone caused modest production of ROS and elastase release, while pretreatment with the toxin caused significant augmentation of chemoattractant (fMLP)-activated ROS generation and release of elastase by activated PMN. These effects of treatment of PMN with SOT were associated with both a marked and sustained elevation of cytosolic Ca2+concentrations and significant increases in the concentrations of extracellular DNA, indicative of NETosis. The current study has identified a potential role for SOT in augmenting the Ca2+-dependent pro-inflammatory interactions of PMN, which, if operative in a clinical setting, may contribute to hyper-activation of PMN and GAS-mediated tissue injury.

7-Year (2015-21) longitudinal surveillance of lefamulin in vitro activity against bacterial pathogens collected worldwide from patients with respiratory tract infections including pneumonia and characterization of resistance mechanisms

OBJECTIVES

Lefamulin (Xenleta™), a pleuromutilin antibiotic, was approved for the oral and IV treatment of community-acquired bacterial pneumonia (CABP) in adults in 2019/2020. This study evaluated the in vitro activity of lefamulin and comparators against 19 584 unique bacterial isolates collected from patients with community-acquired respiratory tract infections and hospitalized patients with pneumonia within the global SENTRY Antimicrobial Surveillance Program during 2015-21.

METHODS

Isolates were susceptibility tested by the CLSI broth microdilution method, and resistance mechanisms were investigated in isolates with elevated lefamulin MICs.

RESULTS

Lefamulin exhibited potent antibacterial activity against the most common and typical CABP pathogens tested, including Streptococcus pneumoniae [MIC50/90, 0.06/0.25 mg/L; 99.9% susceptible (S)], Staphylococcus aureus (MIC50/90, 0.06/0.12 mg/L; 99.6% S), Haemophilus influenzae (MIC50/90, 0.5/2 mg/L; 99.1% S) and Moraxella catarrhalis (MIC50/90, 0.06/0.12 mg/L; 100.0% S). Potent activity was also observed against the less common pneumonia pathogens: β-haemolytic (MIC50/90 of 0.03/0.06 mg/L) and viridans group Streptococcus spp. (MIC50/90 of 0.06/0.25 mg/L) and Haemophilus parainfluenzae (MIC50/90 of 1/4 mg/L). Lefamulin's activity was not adversely affected by resistance to macrolides, penicillin, tetracyclines, fluoroquinolones and other resistance phenotypes. Non-susceptibility/resistance to lefamulin was rare and primarily determined by ribosomal protection through vga(A) variants in S. aureus, overexpression of AcrAB-TolC efflux pump in H. influenzae or modifications in L3, L4 and 23SrRNA in Streptococcus spp.

CONCLUSIONS

Based on the coverage of the most important CABP pathogens and lacking cross-resistance, lefamulin may represent a valuable empirical treatment option for ambulatory and hospitalized patients with CABP, particularly in settings with high prevalence of resistance.

Streptococcus pyogenes Pneumonia: A Rare and Severe Presentation in a Patient With Asthma

Pneumonia is a common respiratory infection typically caused by pathogens such as Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus. It is characterized by inflammation and infection in the lung parenchyma, often presenting with symptoms such as cough, fever, and difficulty breathing. Empyema, on the other hand, is a severe complication of pneumonia marked by the accumulation of pus in the pleural cavity. Streptococcus pyogenes (S. pyogenes), also known as group A Streptococcus (GAS), is a bacterium that can cause various infections, including pharyngitis and skin infections. In rare cases, it can lead to community-acquired pneumonia. In our case report, we describe a 32-year-old female with a history of mild persistent asthma who contracted influenza B virus, eventually developing pneumonia caused by GAS, S. pyogenes.

Group A Streptococcus Pneumonia in a Previously Healthy Individual: Is It Still a Thing?

Group A streptococcus (GAS) is known to cause many different kinds of infections, including invasive pneumonia in rare cases. When it is the causative agent, it is associated with a more severe disease course, but it can often be adequately treated if caught early enough. We hereby present the case of a 32-year-old male with no past medical history who presented with fever, hemoptysis, and tachycardia. Laboratory results showed leukocytosis, hyponatremia, mild transaminitis, and elevated creatine kinase. Initial imaging findings and clinical presentation were concerning for tuberculosis (TB) vs. community-acquired pneumonia (CAP), as it yielded a consolidation in the right upper lobe. The patient had no obvious risk factor except for imprisonment two years prior to symptoms onset. Empirical antibiotics and steroids were started. Quantiferon and acid-fast bacteria (AFB) were negative, but sputum and blood cultures were positive for Streptococcus pyogenes, ruling out TB. Antibiotic therapy was narrowed down. The patient responded well to therapy, with subsequent resolution of symptoms. The current body of knowledge regarding respiratory infections caused by GAS is limited by multiple factors, including its relative rarity and the diversity of how it can present, especially in a developed country. Its mimicry characteristics of other clinical entities, such as TB, can be deceiving, which can delay appropriate treatment if it occurs in settings where the diagnostic tools are not readily available. By sharing more cases and atypical presentations of this disease, the clinical presentations of this pathogen can be more fully understood, and it can be more rapidly identified and treated.

Unusual Suspect: Streptococcus pyogenes as a Cause of Pneumonia

A 73-year-old male patient with a history of hypertension and coronary artery disease presented to the hospital with dyspnea, nonproductive cough, sore throat, and fever. Prior to presentation, the patient was treated for over a week for upper respiratory infection with conservative management. Images were positive for extensive pleural effusions and consolidations, particularly in the right lung. The patient was admitted with the diagnosis of septic shock secondary to acute hypoxic respiratory failure secondary to community-acquired multifocal pneumonia. Blood and pleural fluid cultures confirmed the diagnosis of Streptococcus pyogenes pneumonia complicated with empyema. Despite a challenging hospital course, including renal failure requiring dialysis and surgical interventions for empyema, the patient improved after completing a 21-day antibiotic regimen. Invasive Group A Streptococcus (iGAS) infections can range from mild to life-threatening. Certain viral infections, such as influenza, can exacerbate these infections, particularly in vulnerable populations like the elderly or those with chronic illnesses. Treatment predominantly involves beta-lactams, supplemented by clindamycin in septic cases.

Pathogenic bacteria recovered from Gene X-pert tuberculosis-negative adult patients in Gondar, Northwest Ethiopia

INTRODUCTION

Lower respiratory tract infections (LRTIs) caused by drug-resistant pathogenic bacteria is a major problem in developing countries including Ethiopia. Therefore, this study aimed to determine the pathogenic bacteria and their antimicrobial susceptibility patterns among Gene X-pert tuberculosis-negative adult patients with clinically suspected LRTIs at the University of Gondar Comprehensive Specialized Referral Hospital, Gondar, Northwest Ethiopia.

METHODS

This institutional-based cross-sectional study was conducted from February 01 to March 15, 2020. Socio-demographic data were collected by using a structured questionnaire. A total of 254 sputum specimens were collected from Gene X-pert tuberculosis-negative patients. Bacterial recovery was performed using blood, chocolate, and MacConkey agar plates. Bacterial isolates were identified based on Gram staining, colony characteristics, and biochemical reactions. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method. Methicillin resistance of S. aureus was confirmed using cefoxitin (30 µg). Descriptive statistics were calculated for each variable and results are shown in tables and figures.

RESULTS

In this study, the overall sputum culture positivity rate was 145/254 (57.1%). Gram-negative bacteria 111 (64.9%) were predominant compared to Gram-positive bacteria 60 (35.1%). Of the 145 culture-positive cases, 26 (14.8%) had poly-bacterial infections. S. aureus 40 (66.7%) was the predominant Gram-positive bacterium whereas K. pneumoniae 33 (29.7%), was the most isolated Gram-negative bacterium. Bacterial species, such as S. aureus were sensitive to ciprofloxacin 38/40 (95.0%), gentamicin 37/40 (92.5%), cefoxitin 36/40 (90.0%), and clindamycin 34/40 (85.0%). The proportion of Methicillin-resistant S. aureus was low, 4(10.0%). S. pneumoniae was sensitive to chloramphenicol 8/9 (88.9%) and resistant to ciprofloxacin 6/9 (66.7%). K pneumoniae, P. aeruginosa, E. coli, Serratia species, and H. influenzae also demonstrated high levels of resistance to ampicillin at rates of 21/33 (63.6%), 8/8 (100.0%), 15/17 (88.2%), 7/10 (70.0%), and 6/6 (100.0%), respectively.

CONCLUSION

This study revealed a higher burden of Gram-negative and Gram-positive pathogenic bacterial agents, which is responsible for LRTs. Therefore, routine sputum culture identification and antibiotic susceptibility testing should be performed in Gene X-pert tuberculosis-negative patients.

Bacterial Wars-a tool for the prediction of bacterial predominance based on network analysis measures

Bacterial Wars (BW) is a network-based tool that applies a two-step pipeline to display information on the competition of bacterial species found in the same microbiome. It utilizes antimicrobial peptide (AMP) sequence similarities to obtain a relationship between species. The working hypothesis (putative AMP defense) is that friendly species share sequence similarity among the putative AMPs of their proteomes and are therefore immune to their AMPs. This may not happen in competing bacterial species with dissimilar putative AMPs. Similarities in the putative AMPs of bacterial proteomes may be thus used to predict predominance. The tool provides insights as to which bacterial species are more likely to 'die' in a competing environmental niche.

The effects of air pollutants exposure on the transmission and severity of invasive infection caused by an opportunistic pathogen Streptococcus pyogenes

Currently, urbanization is associated with an increase in air pollutants that contribute to invasive pathogen infections by altering the host's innate immunity and antimicrobial resistance capability. Streptococcus pyogenes, also known as Group A Streptococcus (GAS), is a gram-positive opportunistic pathogen that causes a wide range of diseases, especially in children and immunosuppressed individuals. Diesel exhaust particle (DEP), a significant constituent of particulate matter (PM), are considered a prominent risk factor for respiratory illness and circulatory diseases worldwide. Several clinical and epidemiological studies have identified a close association between PM and the prevalence of viral and bacterial infections. This study investigated the role of DEP exposure in increasing pulmonary and blood bacterial counts and mortality during GAS M1 strain infection in mice. Thus, we characterized the upregulation of reactive oxygen species production and disruption of tight junctions in the A549 lung epithelial cell line due to DEP exposure, leading to the upregulation of GAS adhesion and invasion. Furthermore, DEP exposure altered the leukocyte components of infiltrated cells in bronchoalveolar lavage fluid, as determined by Diff-Quik staining. The results highlighted the DEP-related macrophage dysfunction, neutrophil impairment, and imbalance in pro-inflammatory cytokine production via the toll-like receptor 4/mitogen-activated protein kinase signaling axis. Notably, the tolerance of the GAS biofilms toward potent antibiotics and bacterial resistance against environmental stresses was also significantly enhanced by DEP. This study aimed to provide a better understanding of the physiological and molecular interactions between exposure to invasive air pollutants and susceptibility to invasive GAS infections.

The use of chemometric modelling to determine chemical composition-antimicrobial activity relationships of essential oils used in respiratory tract infections

The antimicrobial effects of essential oils are commonly cited within aromatherapeutic texts for use in respiratory tract infections. These essential oils are inhaled or applied to the skin to treat infections and manage symptoms associated with these conditions. A limited number of these essential oils have been scientifically studied to support these claims, specifically, against respiratory pathogens. This study reports on the minimum inhibitory concentration (MIC) of 49 commercial essential oils recommended for respiratory tract infections, and identifies putative biomarkers responsible for the determined antimicrobial effect following a biochemometric workflow. Essential oils were investigated against nine pathogens. Three essential oils, Amyris balsamifera (amyris), Coriandrum sativum (coriander) and Santalum austrocaledonicum (sandalwood) were identified as having greater activity (MIC value = 0.03-0.13 mg/ml) compared to the other essential oils investigated. The essential oil composition of all 49 oils were determined using Gas Chromatography coupled to Mass Spectroscopy (GC-MS) analysis and the GC-MS data analysed together with the antimicrobial data using chemometric tools. Eugenol was identified as the main biomarker responsible for antimicrobial activity in the majority of the essential oils. The ability of a chemometric model to accurately predict the active and inactive biomarkers of the investigated essential oils against pathogens of the respiratory tract was 80.33%.

Hemorrhagic pneumonia and upper lobe pulmonary cavitary lesion caused by Streptococcus pyogenes

A 33-year-old previously healthy man from Mexico who presented with massive hemoptysis, fevers, chills and found to have cavitary lesions in the right upper lobe of lung was highly suspicious for tuberculosis. The patient was treated with vancomycin, ceftriaxone, azithromycin and placed on isolation for suspected tuberculosis. Sputum AFB stains were negative and blood cultures grew Group A Streptococcus [GAS]. Antibiotics were narrowed down to ampicillin-sulbactam and the patient was discharged with significant clinical improvement. Strep A pyogenes is a rare cause of cavitary hemorrhagic pneumonia but is associated with high mortality. Clinical suspicion and early diagnosis are crucial in saving the patient.

Severe community-acquired pneumonia due to Streptococcus pyogenes in the Newcastle area

Background

An apparent increase in the incidence of severe community-acquired pneumonia (CAP) caused by Streptococcus pyogenes (group A Streptococcus - GAS) was observed during 2017 in the Newcastle area. The study was undertaken to establish whether there was a true increase in severe S. pyogenes pneumonia and to explore its epidemiology and clinical features.

Methods

The study was a retrospective descriptive study of S. pyogenes pneumonia set in two tertiary referral hospitals in Newcastle, a large regional city, during the period 2007 to 2018. Subjects were adults identified as having S. pyogenes pneumonia by searching a database of severe CAP (defined as requiring intensive care unit [ICU] admission) for the period 2007-2018. Laboratory records were also searched for sterile site isolates of S. pyogenes to identify patients not requiring ICU admission.

Results

There were 13 cases of S. pyogenes CAP identified during the study period, of whom 12 (92%) required ICU admission. S. pyogenes accounted for 12/728 (1.6%) cases of severe CAP during the study period. The severity of S. pyogenes pneumonia was high despite a mean patient age of 48 years and 7/13 (54%) having no significant past medical history. The mortality rate was 2/13 (15%). Viral co-infection was found in 6/12 (50%) of patients tested. Overall 7/12 (58%) of the patients with severe S. pyogenes CAP during the study period presented in the winter or spring of 2017.

Conclusions

Streptococcus pyogenes is a rare cause of severe CAP in the Newcastle area, but there was a marked increase in frequency observed during the 2017 influenza season. Further study of the epidemiology of invasive GAS (iGAS) disease in Newcastle is warranted to identify emerging trends in this severe infection.