Research identifies key obstacles faced by this population, ranging from cancer patients to those who are HIV-positive

Immunocompromised patients are becoming a growing segment of those treated in intensive care units (ICUs), presenting a significant challenge due to their vulnerability to opportunistic infections. A study recently published in the scientific journal *Intensive Care Medicine*, involving the D’Or Institute for Research and Education (IDOR), aimed to explore the epidemiology of these infections and propose new approaches for prevention and treatment in critical care settings.

The population of immunocompromised patients in the ICU is quite heterogeneous. Immunosuppressive conditions include inherited or acquired immunodeficiencies, often related to cancer treatment or autoimmune diseases, hematologic disorders, organ transplantation, or HIV infection. It is estimated that about one-third of ICU patients have at least one risk factor for immunosuppression, and cancer patients account for approximately one in six ICU admissions.

Given that these patients may be at higher risk during hospitalization in intensive care units, the current study sought to analyze the epidemiology of ICU-acquired infections to provide foundational information for the development of more effective diagnostic tools and preventive treatments. The research involved an extensive analysis of data from scientific publications over the past 20 years, focusing on terms related to immunosuppression, infections, and antimicrobial resistance.

Antibiotic Resistance in Immunocompromised Patients

Among the infections in immunocompromised patients in the ICU, bloodstream infections (BSIs) are among the most concerning due to their association with significantly increased mortality. These infections can occur through catheters and lead to the proliferation of bacteria, which, if unchecked, can result in severe clinical complications.

Some studies analyzed by the researchers indicate that immunosuppression increases the risk of mortality in these cases, such as the EUROBACT study, which found that patients with hospital-acquired BSIs, especially in the ICU, had a higher risk of mortality when immunocompromised.

This patient population is also particularly susceptible to respiratory infections associated with ventilation, such as ventilator-associated pneumonia (VAP) and ventilator-associated tracheobronchitis (VAT). European and American guidelines consider immunosuppression a risk factor for multidrug-resistant bacteria, recommending the use of broad-spectrum antibiotics.

According to the authors, because these patients often require this type of antibiotic, resistance to these drugs is a growing concern among immunocompromised patients in the ICU. The inappropriate use of these treatments contributes to the increasing antimicrobial resistance that some pathogens develop in the hospital environment.

A promising strategy in these cases would be to personalize treatment based on the specific resistance profile of the pathogens. Additionally, future studies need to focus on better understanding the dynamics of this resistance to improve treatment strategies and clinical outcomes for this patient population.

Viral and Fungal Infections

Viral infections can be acquired in the hospital or represent a reactivation of latent viruses. The most common viruses in immunocompromised patients include influenza, parainfluenza, human metapneumovirus, coronavirus, adenovirus, RSV, and rhinovirus, which can cause pneumonia and other respiratory complications.

The diagnosis of these infections is usually made by PCR tests, which allow for rapid and accurate detection of pathogens. The use of corticosteroids in viral infections is controversial and should be based on specific evidence. The authors note that a lack of response to antiviral treatment or recurrence of the infection may indicate viral resistance, requiring adjustments to therapy.

Immunocompromised patients are also at risk for invasive fungal infections, primarily caused by Candida and Aspergillus. The mortality associated with these infections is high, and treatment involves antifungal medications combined with strict control of infection sources.

Preventive measures include air filtration in ICUs and prophylactic antifungal treatment with posaconazole for patients at high risk of invasive fungal infections. Additional studies are needed to evaluate the effectiveness of these preventive strategies in different subpopulations of immunocompromised patients.

Future Research Areas

To overcome the challenges in caring for immunocompromised patients in the ICU, researchers have identified several key areas for future studies, one of which is the development of accessible methods to assess the immunosuppression status of critical patients, allowing for more personalized treatments for each patient.

Another area for improvement is gaining a more precise understanding of the risk factors and microbiology of ICU infections, as well as identifying biomarkers of immunosuppression to design clinical trials for precision immunotherapies.

A topic that is increasingly gaining attention in this context is the investigation of the patients’ microbiota. According to the authors, this population of microorganisms may play a very significant role in infection prevention and could be associated with other immune-stimulating therapies.

The current study highlights the main factors that make immunocompromised patients a population susceptible to opportunistic infections and antimicrobial resistance in ICUs. The issues raised by the research underscore the urgent need to develop better prevention, diagnostic, and treatment strategies, thereby improving outcomes for this critical patient segment.

Written by Maria Eduarda Ledo de Abreu.