Are Antibiotic-Resistant Infections in COVID-19 Patients Accelerating the Post-Antibiotic Era?

The COVID-19 pandemic has deeply disrupted the management of patients in intensive care, while exacerbating another major challenge of modern medicine: antibiotic resistance. Between 2020 and 2022, a study conducted in a Brazilian intensive care unit revealed that nearly 29% of patients with severe forms of COVID-19 developed nosocomial infections—those contracted in the hospital. These infections, often caused by multidrug-resistant bacteria, prolonged stays in intensive care and increased the already high mortality rate of 54.4%.

The most frequent infections were ventilator-associated pneumonias and bloodstream infections. The bacteria involved were predominantly Gram-negative bacilli, such as Acinetobacter baumannii and Klebsiella pneumoniae, two species known for their resistance to carbapenems, a last-resort class of antibiotics. Nearly 94% of Acinetobacter baumannii strains and 86% of Klebsiella pneumoniae strains identified in this study exhibited this resistance. This situation drastically limits the available therapeutic options, as carbapenems are often used as a last resort to treat severe infections.

Another concerning phenomenon was observed: 21.4% of the isolated Gram-negative bacteria were naturally resistant to polymyxin B, a potent antibiotic generally effective against multidrug-resistant strains. Among these bacteria were Serratia, Providencia stuartii, Burkholderia cepacia, and Stenotrophomonas maltophilia. The presence of these pathogens further complicates management, as they reduce the effectiveness of available treatments. Additionally, Ralstonia mannitolilytica, though less well-known, was also identified as having reduced sensitivity to polymyxins.

Patients infected with carbapenem-resistant strains had a nearly threefold higher risk of death than others. This association was confirmed by in-depth statistical analysis, which also showed that mechanical ventilation—often essential for severe COVID-19 cases—multiplied the risk of mortality by more than four. This link is partly explained by the fact that mechanical ventilation reflects advanced clinical deterioration, but also by the increased risk of nosocomial infections associated with the prolonged use of invasive devices such as catheters or endotracheal tubes.

Fungi, particularly those of the Candida genus, also played a significant role, accounting for 13.1% of nosocomial infections. Their presence was especially notable in bloodstream infections, where they constituted 25.5% of cases. The increase in candidemia among COVID-19 patients in intensive care is explained by the weakening of the immune system, often worsened by the use of high-dose corticosteroids to combat severe pulmonary inflammation. These treatments, while necessary to save lives, have also promoted the development of opportunistic infections.

The study also highlighted a clinical paradox: despite a very low rate of confirmed bacterial co-infections at admission, more than 87% of patients received antibiotics upon arrival at the hospital. This practice, driven by the difficulty in distinguishing a viral infection from a bacterial superinfection, contributed to exerting intense selective pressure on bacteria, thereby accelerating the emergence of resistance. The most common initial treatments combined ceftriaxone and azithromycin, a combination frequently used for community-acquired pneumonias. However, clinical trials have since demonstrated that azithromycin provides no benefit in the treatment of COVID-19, raising questions about the excessive use of this antibiotic.

Prolonged stays in intensive care, often necessary for the most severe patients, also played a key role. Patients who developed a nosocomial infection stayed in intensive care for an average of 15 days, compared to just 7 days for those without infection. Among survivors, this difference was even more pronounced: 19 days with infection versus 6 days without. These prolonged stays not only increase the risk of secondary infections but also the costs and workload for healthcare teams, already severely strained by the pandemic.

Most nosocomial infections occurred in 2021, the year when the intensive care unit admitted the highest number of patients, with 229 admissions compared to 71 in 2020. This sudden increase overwhelmed available resources, including healthcare personnel and protective equipment, creating an environment conducive to the spread of infections. In 2022, although the unit’s capacity was maintained, the number of admissions decreased, and with it, the number of infections, suggesting that the experience gained and improved prevention protocols may have played a protective role.

Gram-positive bacteria, such as Enterococcus faecalis or Staphylococcus epidermidis, were less common, but their presence in bloodstream infections serves as a reminder that invasive medical devices, such as central venous catheters, remain a major entry point for these pathogens. Their treatment, while often simpler than that of Gram-negative bacteria, requires heightened vigilance to avoid complications.

This study illustrates how the COVID-19 pandemic acted as an accelerator of the antibiotic resistance crisis. The extreme conditions encountered in intensive care, with massive use of broad-spectrum antibiotics and overwhelmed services, promoted the emergence and dissemination of resistant bacterial strains. Pre-pandemic projections already estimated that resistant infections could cause up to 10 million deaths per year by 2050, surpassing the combined mortality of cancer, diabetes, and road traffic accidents. The recent health crisis has likely accelerated this trend, making it more urgent than ever to strengthen infection prevention strategies and antibiotic management.

Credits

Source Study

DOI: https://doi.org/10.1186/s12982-026-02190-9

Title: Multidrug resistant infections in COVID-19 patients drive the transition toward a post antibiotic era

Journal: Discover Public Health

Publisher: Springer Science and Business Media LLC

Authors: Alex Mauricio Garcia Santos; Eliane Campos Coimbra; Jakson Gomes Figueiredo; João Vitor Alves de Menezes Feitosa; Diego Lins Guedes