One in ten COVID-19 patients develop dangerous bloodstream infections

The study paints a stark picture of how secondary bacterial infections complicate the course of COVID-19, especially in severely ill and immunocompromised patients. These infections often develop due to prolonged hospitalization, mechanical ventilation, or the overuse of corticosteroids and antibiotics during treatment.

A new global study reveals alarming findings on the scale and severity of bloodstream infections (BSIs) among COVID-19 patients. The study, titled “Global Burden of Bloodstream Infections in COVID-19: Prevalence, Antimicrobial Resistance, and Mortality Risk,” published in Viruses, provides a comprehensive global synthesis of how these infections worsen outcomes, elevate mortality, and accelerate antimicrobial resistance in hospitals worldwide.

The research analyzed data from 22 observational studies published between January 2020 and August 2025, encompassing more than 123,000 COVID-19 patients and over 600,000 blood cultures. Using a systematic review and meta-analysis registered under PROSPERO CRD420251089511, the authors examined how often BSIs occur in COVID-19 cases, the types of pathogens responsible, and the role of antibiotic resistance in worsening patient outcomes.

Bloodstream infections: A hidden crisis within the COVID-19 pandemic

The results revealed that bloodstream infections were present in 8.2% of COVID-19 patients globally, with the prevalence rising to 12.5% among intensive care unit (ICU) patients. Even more concerning, pediatric cases showed a 10.8% prevalence, highlighting that children, especially those with multisystem inflammatory syndrome (MIS-C), were not spared. In contrast, patients in non-ICU settings showed lower rates of 5.2%, suggesting that the severity of infection correlates strongly with hospital intensity and invasive treatment.

The study paints a stark picture of how secondary bacterial infections complicate the course of COVID-19, especially in severely ill and immunocompromised patients. These infections often develop due to prolonged hospitalization, mechanical ventilation, or the overuse of corticosteroids and antibiotics during treatment.

Antibiotic resistance escalates as gram-negative bacteria dominate

The study found the dominance of Gram-negative bacteria, which accounted for 61% of all BSI cases. The most frequent pathogens included Klebsiella pneumoniae (26%) and Acinetobacter baumannii (21%), followed by Gram-positive organisms such as Enterococcus spp. (18%) and Staphylococcus aureus (13%). These results demonstrate a troubling shift in hospital microbiology during the pandemic, with multidrug-resistant organisms emerging as leading causes of death in COVID-19 patients.

Antimicrobial resistance (AMR) was a recurring and alarming theme throughout the research. The authors found that 36% of S. aureus isolates were methicillin-resistant (MRSA), while 31% of Enterobacterales were extended-spectrum beta-lactamase (ESBL) producers. These resistance rates far exceed pre-pandemic European averages, showing how COVID-19 disrupted infection control and antimicrobial stewardship practices across health systems.

The widespread use of empirical antibiotics in early pandemic stages, often administered preemptively to manage uncertainty, fueled the rise of resistant strains. The study notes that many ICUs worldwide, already operating under pressure, struggled to maintain stringent hygiene and infection control standards during the pandemic’s peak. This allowed opportunistic bacteria to thrive, increasing the risk of multidrug-resistant infections in critically ill patients.

The authors stress that antimicrobial resistance was not evenly distributed. Regions in Asia-Pacific and Latin America exhibited the highest resistance levels and infection prevalence, pointing to the role of resource disparities, variable diagnostic capacity, and inconsistent antibiotic policies in shaping global outcomes.

Mortality and clinical impact: A dangerous link between COVID-19 and secondary infections

Apart from prevalence and microbiology, the study provides a grim assessment of patient outcomes. COVID-19 patients who developed BSIs were found to have a 2.6 times higher risk of death than those without infection. Mortality among BSI patients averaged 42%, compared to 10–20% among non-BSI COVID-19 cases.

These infections also prolonged hospital stays by an average of 6.8 additional days and increased the likelihood of ICU admission by more than threefold. Key risk factors included mechanical ventilation, immunosuppression, and corticosteroid therapy, all common in severe COVID-19 management. Each of these interventions, while necessary for survival, creates conditions conducive to bacterial invasion and biofilm formation in hospital equipment, heightening infection risk.

In pediatric patients, particularly those with MIS-C, the study observed an even greater vulnerability. The inflammatory and immune dysregulation associated with MIS-C appeared to double the likelihood of bloodstream infection, underscoring the importance of strict infection control in pediatric COVID-19 wards.

The impact of BSIs extends beyond individual cases, it places immense pressure on healthcare systems, increases costs, and undermines post-pandemic recovery. The intersection of viral and bacterial infections during the pandemic years, they argue, has set back global progress in antimicrobial resistance containment by several years.

To sum up, the global burden of bloodstream infections during the COVID-19 era represents a critical inflection point in infectious disease management. This study calls for urgent action to strengthen infection prevention and antimicrobial stewardship programs, particularly in low- and middle-income countries where diagnostic limitations and inconsistent data collection mask the true scale of the problem.

The researchers recommend that hospitals adopt harmonized diagnostic criteria, such as those from the CDC or ECDC, to ensure comparable reporting across regions. Regular AMR surveillance, supported by international databases, could help track pathogen evolution and guide antibiotic policy. Additionally, integrating rapid diagnostic testing and AI-based monitoring systems may improve early detection of bloodstream infections, allowing clinicians to tailor treatments more effectively.