Research led in Bellvitge will allow progress in the fight against bacteremia

A group of researchers from 19 state university hospitals, under the direction of doctors Miquel Pujol and Jordi Carratalà, researchers from the Bellvitge Biomedical Research Institute (IDIBELL) and the Infectious Diseases Service of the Bellvitge University Hospital (HUB), published the results of a clinical trial evaluating the efficacy of combined treatment with fosfomycin and cloxacillin in patients with bacteremia due to methicillin-sensitive Staphylococcus aureus (MSSA). This study carried out in collaboration with the Infectious Diseases Services, Pharmacy, Microbiology, and the Clinical Trials Unit of the HUB, was published in the journal Nature Medicine.

MSSA bacteremia represents a major global health challenge, with high rates of therapeutic failure and mortality. With the standard use of cloxacillin as monotherapy, there is increasing interest in finding new treatment strategies to improve outcomes. Despite some promising evidence of synergy between fosfomycin and cloxacillin in in vitro studies, animal models, and clinical observations, the efficacy of the combined use of these antibiotics has not been evaluated in a randomized clinical trial until now.

The clinical trial, led by IDIBELL and the HUB, concluded that combined treatment with fosfomycin and cloxacillin does not significantly improve therapeutic success in hospitalized patients with MSSA bacteremia, compared to treatment with cloxacillin as monotherapy. The overall mortality rate and serious adverse events were similar in both treatment groups, except for the persistence of bacteremia on the third day, which was less frequent in the group that received the combined treatment.

Despite this finding, the important problem of MSSA bacteremia persists, and more clinical trials are needed to explore new treatment strategies that may improve patient prognosis. “Ideally, these trials should be designed taking into account the intrinsic diversity of the infection and more personalized long-term follow-up,” according to doctors Pujol and Carratalà, leaders of the study.

The research team also observed that in patients who received fosfomycin, the presence of S. aureus in the blood decreased more rapidly. This could be relevant to reduce complications and mortality associated with this infection.

A common bacteria in the healthy population

Staphylococcus aureus, known as S. aureus, is one of the most common causes of bacteremia and sepsis. In fact, it is a bacteria that is usually present on the skin in 30-50% of the healthy population. Therefore, infections are not always acquired in the healthcare setting and can also be acquired in the community.

In the healthcare field, when it is necessary to alter the body’s defensive barriers, for example during a surgical procedure or the insertion of a vascular catheter, S. aureus finds an “ideal” access door to produce infections that can lead to bloodstream infection. For this reason, nursing and medical professionals who perform invasive procedures know and apply appropriate prevention measures. However, these procedures are currently performed more frequently in an elderly population, more susceptible to infections in return for greater longevity.

This bacteria, with its virulence, can cause serious infections, including infection of heart valves and joints. S. aureus infections are associated with a high mortality rate, which can range from 15% to 30%, even with standard cloxacillin treatment.

One million deaths in the world every year

Antibiotic resistance is a growing threat to public health, and research remains essential to address this issue and ensure effective treatment for bacterial infections. The VINCat program, created in Catalonia in 2007 by the Catalan Health Service, is an example of addressing this problem and aims to prevent infections related to healthcare, including those caused by S. aureus, and monitor antibiotic use.