The increased availability of antimicrobials and advancements in medical technologies have led to progress in infection management but also challenges, particularly with the rise of drug resistance. A study conducted by the United Kingdom government estimates that by 2050, infections caused by multidrug-resistant organisms will be associated with 10 million deaths per year [1]. In 2019 it was reported that multidrug-resistant lower respiratory tract infections caused approximately 1.5 million deaths [2]. This scenario has significant social, human, and economic consequences, compromising treatment efficacy, limiting therapeutic options, and leading to increased hospitalization rates, hospital length of stays (HLOS), and patient morbidity and mortality [2]. Therefore, efforts have been made to balance the need for broad-spectrum antibiotic therapy with these associated drawbacks.

Pulmonary infections, such as community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP), are among the leading causes of morbidity and mortality in hospitalized patients, particularly in intensive care unit (ICU) patients [3]. Their treatment traditionally involves the empirical use of broad-spectrum antibiotics, including agents targeting MRSA, a pathogen associated with potentially severe pneumonia [4]. While the early administration of glycopeptides, such as vancomycin, is essential to improving survival rates in critically ill patients, this approach must be associated with the rapid identification of the etiological agent to prevent prolonged and unnecessary use of potentially toxic drugs [5]. In fact, vancomycin is an important antimicrobial in the therapy of bacterial pneumonia caused by MRSA, despite having properties that challenge its clinical success, such as a slow bactericidal effect, a profile of important adverse reactions such as allergic reactions, red neck syndrome and relevant nephrotoxicity, and erratic penetration into some organs and tissues [6].

Through the integration of diagnostic tools that generate rapid results, including MRSA nasal swab screening tests, antimicrobial stewardship programs might positively support focused therapy and reduce unneeded exposure to microbiological agents such as vancomycin, which are ultimately related to nephrotoxicity and other systemic complications [6,7].

Screening methods for identifying specific pathogens offer a safe way to narrow the spectrum of antibiotic therapy when combined with careful clinical interpretation, reducing selective pressure and limiting bacterial resistance development. In this context, nasal swabs using polymerase chain reaction (PCR) technology have emerged as an effective tool to guide therapeutic decisions in cases of suspected MRSA pneumonia. This test enables the rapid detection of MRSA colonization within the anterior nares, which is a site greatly associated with upper respiratory tract colonization in individuals at risk, as suggested in recent meta-analyses reporting a negative predictive value (NPV) above 95 % for pneumonia caused by this pathogen [7]. Thus, a negative result can safely rule out MRSA infection, allowing antimicrobial de-escalation in patients with pneumonia of unknown etiology. Other screening methods with similar objectives include respiratory secretion cultures, nasal swab cultures, and PCR testing in samples from different sites, such as the oropharynx, tracheal aspirates, and bronchoalveolar lavage, each with its specific indications and limitations [8]. The essential clinical usability of such screening protocols lies in their ability to assist early and timely vancomycin discontinuation, thereby decreasing drug-induced toxicity, reducing selection pressure, and fostering cost savings and enhanced patient outcomes. However, despite the gradual implementation of PCR testing on nasal swab samples as a screening tool in various healthcare institutions, few studies have been conducted to assess its impact on the rational use of antimicrobials and on hospitalization-related complications, as well as the use of broad-spectrum drugs such as vancomycin.

Therefore, this literature synthesis, which includes a series of meta-analyses, aims to summarize the existing evidence on the clinical impact of MRSA nasal swab screening in hospitalized patients with pneumonia, with a particular focus on its influence on vancomycin use and duration, HLOS, mortality, and the incidence of acute kidney injury (AKI).