Co-infection with Legionella and SARS-CoV-2: a case report

The Global Burden and Trends of Legionella spp. Infection-Associated Diseases from 1990 to 2021: An Observational Study

BACKGROUND

Legionella infections are a major global health issue, yet there's limited research on their impact and trends. We aimed to systematically analyzed the long-term trends in Legionella spp. infection-associated diseases (LSIADs) burden from 1990 to 2021.

METHODS

Age-standardized disability-adjusted life years (ASR-DALYs) and age-standardized death rates (ASDRs) of LSIADs from 1990 to 2021 were accessed from the Global Burden of Disease (GBD) 2021, which utilized the Bayesian hierarchical meta-regression tool and the Cause of Death Ensemble model to estimate these metrics. Trends in disease burden across age, sex, region, and Socio-Demographic Index (SDI) levels were estimated using annual percentage changes (EAPCs) and annual percentage changes (APCs).

RESULTS

Globally, the ASR-DALYs and ASDRs for LSIADs in 2021 were 24.74 and 0.86 per 100,000, respectively, with the highest rates observed in regions with low SDI. From 1990 to 2021, while the overall burden of LSIADs showed a downward trend, the highest ASR-DALYs (101.85 per 100,000) and ASDRs (8.15 per 100,000) were observed in individuals over 70 years of age, accompanied by a corresponding increase in deaths (EAPCs = 0.17%, 95% CI: 0.09-0.26%). Furthermore, increases in ASR-DALYs and ASDRs for LSIADs were also noted among those aged 15-49 years (EAPCs = 0.43% and 0.57%, respectively) and those aged 50-69 years (EAPCs = 0.14% and 0.09%, respectively).

CONCLUSION

Higher disease burdens and increasing trends have been observed in specific age groups and regions, which require the implementation of water quality management plans, enhanced readiness of health facilities, and improved sanitation infrastructure.

Co-Infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV-2) and Human Coronavirus HKU1 (HCoV-HKU1)

Introduction

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human coronavirus HKU1 (HCoV-HKU1) are two forms of human coronaviruses known to cause respiratory tract symptoms. A co-infection with both viruses is rare, particularly in the United States.

Case description

An 85-year-old male presented to the Emergency Department with recurrent falls, diarrhoea and cough, and whose viral panel was positive for both SARS-COV-2 and HCoV-HKU1. The patient developed bacterial pneumonia and was treated with antibacterial agents and glucocorticoids. His past medical history of atrial fibrillation required careful monitoring and subsequent discontinuation of remdesivir, a medication known to cause adverse cardiovascular effects in COVID-19 patients. The length of stay was also prolonged due to delirium and deconditioning. Ultimately, the patient required an urgent ablation followed by the placement of a permanent pacemaker, and anticoagulation therapy was initiated before discharge. The patient had a favourable outcome given the rarity of this case.

Discussion

COVID-19 patients co-infected with other human coronaviruses should be monitored for disease progression and superimposed bacterial infections. Providers should be cautious with the use of remdesivir in cases of co-infection and in severely ill COVID-19 patients who have a history of atrial fibrillation.

LEARNING POINTS

This is a rare clinical case of a patient co-infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human coronavirus HKU1 (HCoV-HKU1), two forms of coronaviruses; the report presents an epidemiological anomaly and a treatment framework.The importance of close monitoring of bacterial infections in coronavirus co-infections is reinforced.The cautious use of remdesivir in patients with a history of atrial fibrillation in severe or unique COVID-19 disease is recommended.

Diagnosis of Legionnaires' Disease Assisted by Next-Generation Sequencing in a Patient with COVID-19

Coinfection in COVID-19 patients is associated with worsening outcome. Among patients with COVID-19, Legionella pneumophila, a common cause of pneumonia, has been reported as a co-occurring respiratory infection. A nonspecific clinical presentation, however, makes an early diagnosis difficult. Bronchoalveolar lavage fluid was collected from a patient suffering from COVID-19 and presenting with pneumonia and sent for metagenomic analysis. Differential abundance analysis was carried out by comparing each taxon reads per million between the bronchoalveolar lavage fluid sample and the negative control. Two replicates of metagenomic sequencing were conducted on bronchoalveolar lavage fluid samples. Within each replicated sequencing, one negative control was sequenced for comparison of taxon abundance in the BALF sample. In both replicates, Legionella pneumophila was the only taxon with significantly higher abundance when compared with the negative control. PCR of the bronchoalveolar further confirmed the presence of L. pneumophila. Several studies have estimated that the incidence of Legionnaires' disease co-infection in patients with COVID-19 infection is approximately 0% to 1.5%. There are some common characteristics of COVID-19 and co-infection with Legionnaires' disease, making it difficult to diagnose bacterial infection early. The diagnosis of these cases is important due to the different treatments used. Current diagnostic tests for Legionnaires' disease include conventional culture, urinary antigen for L. pneumophila serogroup 1, polymerase chain reaction, direct fluorescent antibody stain, and paired serology. The current study demonstrated that metagenomics is a promising approach that facilitated the diagnosis of Legionnaires' disease.

A Patient with Concurrent Legionella and COVID-19 Infection in a UK District General Hospital

A 65 year-old gentleman had been brought to our Respiratory Emergency Department for patients with respiratory symptoms and a possible COVID-19 infection with a 3-day history of shortness of breath (SOB), fever, a productive cough of yellow sputum, and right-sided chest pain. The patient had received both vaccinations at the time and initially reported no travel history, although later it was revealed that he had recently stayed at a hotel. He tested positive for COVID-19 and had hyponatremia and a raised procalcitonin, indicating a bacterial infection as well. He had been initiated on our local treatment guidelines for COVID with antibiotics, guided by local hospital guidelines. An atypical pneumonia screen returned a positive result for Legionella urine antigen, and his antibiotic regime was changed accordingly. Our patient deteriorated significantly, and despite being escalated to our intensive care unit (ICU), he unfortunately passed away. Our case highlights the importance of early ICU involvement and escalation of antibiotics in cases of suspected concurrent Legionella and COVID-19 infections.

Legionella pneumophila: The Journey from the Environment to the Blood

An outbreak of a potentially fatal form of pneumonia in 1976 and in the annual convention of the American Legion was the first time that Legionella spp. was identified. Thereafter, the term Legionnaires’ disease (LD) was established. The infection in humans is transmitted by the inhalation of aerosols that contain the microorganisms that belong to the Legionellaceae family and the genus Legionella. The genus Legionella contains genetically heterogeneous species and serogroups. The Legionella pneumophila serogroup 1 (Lp1) is the most often detected strain in outbreaks of LD. The pathogenesis of LD infection initiates with the attachment of the bacterial cells to the host cells, and subsequent intracellular replication. Following invasion, Legionella spp. activates its virulence mechanisms: generation of specific compartments of Legionella-containing vacuole (LCV), and expression of genes that encode a type IV secretion system (T4SS) for the translocation of proteins. The ability of L. pneumophila to transmigrate across the lung’s epithelium barrier leads to bacteremia, spread, and invasion of many organs with subsequent manifestations, complications, and septic shock. The clinical manifestations of LD depend on the bacterial load in the aerosol, the virulence factors, and the immune status of the patient. The infection has two distinct forms: the non- pneumatic form or Pontiac fever, which is a milder febrile flu-like illness, and LD, a more severe form, which includes pneumonia. In addition, the extrapulmonary involvement of LD can include heart, brain, abdomen, and joints.

Legionella pneumophila and Staphylococcus aureus co-infections in a patient with SARS-CoV-2

A man fully mRNA-vaccinated against COVID-19 presented to our hospital with an acute febrile illness, respiratory symptoms and a positive test for SARS-CoV-2. He was later found early into hospitalisation to have two morbid bacterial co-infections: Legionella pneumophila serogroup 1 and methicillin-resistant Staphylococcus aureus (MRSA). Although this patient was initially admitted for COVID-19 management, his initial presentation was remarkable for lobar pneumonia, hyponatraemia and rhabdomyolysis more compatible with Legionnaire's disease than severe COVID-19. On discovery of MRSA pneumonia as a second bacterial infection, immunosuppressive COVID-19 therapies were discontinued and targeted antibiotics towards both bacterial co-infections were initiated. The patient's successful recovery highlighted the need to have high suspicion for bacterial co-infections in patients presenting with community-acquired pneumonia and a positive SARS-CoV-2 test, as patients with serious bacterial co-infections may have worse outcomes with use of immunosuppressive COVID-19 therapies.

SARS-CoV-2-Legionella Co-Infections: A Systematic Review and Meta-Analysis (2020-2021)

Legionnaires' Disease (LD) is a severe, sometimes fatal interstitial pneumonia due to Legionella pneumophila. Since the inception of the SARS-CoV-2 pandemic, some contradictory reports about the effects of lockdown measures on its epidemiology have been published, but no summary evidence has been collected to date. Therefore, we searched two different databases (PubMed and EMBASE) focusing on studies that reported the occurrence of LD among SARS-CoV-2 cases. Data were extracted using a standardized assessment form, and the results of such analyses were systematically reported, summarized, and compared. We identified a total of 38 articles, including 27 observational studies (either prospective or retrospective ones), 10 case reports, and 1 case series. Overall, data on 10,936 SARS-CoV-2 cases were included in the analyses. Of them, 5035 (46.0%) were tested for Legionella either through urinary antigen test or PCR, with 18 positive cases (0.4%). A pooled prevalence of 0.288% (95% Confidence Interval (95% CI) 0.129-0.641), was eventually calculated. Moreover, detailed data on 19 co-infections LD + SARS-CoV-2 were obtained (males: 84.2%; mean age: 61.9 years, range 35 to 83; 78.9% with 1 or more underlying comorbidities), including 16 (84.2%) admissions to the ICU, with a Case Fatality Ratio of 26.3%. In summary, our analyses suggest that the occurrence of SARS-CoV-2-Legionella infections may represent a relatively rare but not irrelevant event, and incident cases are characterized by a dismal prognosis.