Even with the intensive efforts by public health programs to control and prevent it, non-typhoidal Salmonella (NTS) infection remains an important public health challenge. It is responsible for approximately 150 million illnesses and 60,000 deaths worldwide annually. NTS infection poses significant risks with high rates of morbidity and mortality, leading to potential short- and long-term complications. There is growing concern among health authorities about the increasing incidence of antimicrobial resistance, with multidrug resistance totaling 22.6% in Europe, highlighting an urgent need for new therapeutic approaches. Our review aims to provide a comprehensive overview of NTS infection. We outline the molecular mechanisms involved in the pathogenesis of NTS infection, as well as the events leading to invasive NTS infection and the subsequent complications associated with it. Given the widespread implications of antimicrobial resistance, our review also presents the global landscape of resistance, including multidrug resistance, and delve into the underlying mechanisms driving this resistance. The rising rates of antibiotic resistance frequently lead to treatment failures, emphasizing the importance of investigating alternative therapeutic options. Therefore, in this review we also explore potential alternative therapies that could offer promising approaches to treating NTS infections.

The increasing incidence of antibiotic resistance in bacteria is a major problem in terms of therapeutic options, especially in immunocompromised patients, such as patients from intensive care units (ICUs), HIV-positive patients, patients with malignancies or transplant patients. Commensal bacteria, especially anaerobes, serve to maintain microbial stability by preventing overpopulation with pathogenic bacteria. In immunocompromised patients, microbiota imbalance caused by antibiotic therapy and decreased host immunity favors intestinal overpopulation with pathogenic species, leading to increased bacterial translocation and susceptibility to systemic infections. Infections with multidrug-resistant (MDR) bacteria pose major challenges to the establishment of appropriate treatment and lead to increased mortality. Asymptomatic colonization with MDR bacteria usually precedes infection and tends to persist for long periods of time, and in immunocompromised patients, colonization with MDR bacteria is a risk factor for systemic infections. This review aims to assess the relation between colonization and infection with MDR bacteria in immunocompromised patients such as ICU patients, HIV-positive patients and cancer patients and to identify the prevalence and patterns of MDR bacterial colonization and infection in this category of patients.

Background: The rise in multidrug-resistant (MDR) Gram-negative bacteria (GNB) poses a critical threat to global health, exacerbated by the increased use of antibiotics during the SARS-CoV-2 pandemic. Colistin, often considered a last-resort antibiotic, has seen heightened usage, raising concerns about resistance and clinical outcomes. This study investigates the evolution of colistin resistance in GNB during the SARS-CoV-2 pandemic, with a focus on clinical outcomes in colistin-treated patients. Methods: Conducted in “Saint Spiridon” Hospital, Iasi, Romania, the study assesses antibiotic usage, trend in GNB resistance to colistin, and mortality rates across distinct pandemic phases (pre-pandemic, Delta, Omicron, and post-pandemic). A retrospective longitudinal analysis spanning 2011 to 2023 was performed. Statistical models were employed to analyze mortality risk and assess the pandemic’s impact on antimicrobial dynamics. Results: Colistin usage increased significantly during the pandemic, with the highest doses recorded during the Omicron phase. Resistance to colistin, particularly among A. baumannii and K. pneumoniae, was associated with increased mortality rates. The statistical model demonstrated robust predictive accuracy for mortality across the pandemic phases, with an AUC of 0.866 in the post-pandemic period. The findings underscore the critical role of A. baumannii as a driver of adverse outcomes, with co-infections significantly linked to systemic infections and higher mortality. Conclusions: The study highlights the evolving trends in colistin therapy and resistance, emphasizing the pandemic’s impact on antimicrobial stewardship and the persistent challenges posed by MDR pathogens. We emphasize the need for antimicrobial resistance surveillance, including the monitoring of colistin resistance, which is considered a last-resort antibiotic.

Background/Objectives: Healthcare-associated infections caused by multidrug-resistant (MDR) bacteria pose a significant and growing public health challenge, particularly in high-risk settings such as Intensive Care Units (ICUs). Colonization is often asymptomatic but can precede infection and contribute to hospital outbreaks, making early detection critical for infection control and containment. The aim of the study is to evaluate the antibiotic susceptibility patterns of MDR bacteria involved in colonization and/or infection among patients admitted to the ICU at a tertiary care hospital in Northeastern Romania and to investigate the relationship between MDR bacterial colonization and subsequent infection. Methods: A total of 118 patients from ICU were included in this study and a total of 609 bacterial strains were isolated, involved in both colonization and infection, with multiple isolates per patient included if obtained from different sites or time points. Results: A predominance of Gram-negative bacilli was found to be involved in both colonization and infection in the ICU, with Acinetobacter baumannii (n = 146; 26.64%), Klebsiella pneumoniae (n = 146; 26.64%), Escherichia coli (n = 60; 10.95%), and Pseudomonas aeruginosa (n = 56; 10.22%) as the main bacteria involved in colonization, and A. baumannii (n = 23; 37.7%), K. pneumoniae (n = 19; 31.1%), and P. aeruginosa (n = 15; 24.6%) as the main bacteria involved in infections. The study revealed a high diversity of antibiotypes among K. pneumoniae (43 distinct antibiotypes), E. coli (35 distinct antibiotypes) and P. aeruginosa (27 distinct antibiotypes). In contrast, only 6 antibiotypes were identified for A. baumannii, with most strains belonging to a single dominant antibiotype. For K. pneumoniae, E. coli and A. baumannii, infections mainly involved the same antibiotype as that found in colonization, while infections with P. aeruginosa were often linked to different antibiotypes than those involved in colonization. Conclusions: This study demonstrates a high colonization-to-infection link among ICU patients in a Northeastern Romanian tertiary care hospital, and these findings underscore the importance of systematic colonization screening to identify patients at high risk in ICU settings.

Even with significant advances in therapeutic interventions and monitoring protocols, cystic fibrosis (CF) remains a critical pediatric health challenge affecting respiratory function and long-term patient outcomes. CF, caused by mutations in the CFTR gene, disrupts normal mucociliary clearance and creates conditions for chronic respiratory infections. The disorder affects individuals globally, with pediatric patients facing particularly complex microbial challenges that evolve throughout childhood growth. CF poses significant risks with progressive lung function decline and increased mortality, leading to potential short- and long-term respiratory complications. There is a growing concern among clinicians about the dynamic nature of airway microbial communities, with classical pathogens like Pseudomonas aeruginosa and Staphylococcus aureus showing sequential emergence patterns that complicate treatment strategies, highlighting an urgent need for microbiome-informed therapeutic approaches. Our review aims to provide a comprehensive overview of airway microbiome evolution in pediatric CF patients. We outline the molecular and ecological mechanisms involved in microbial community progression, as well as the age-related trajectories leading to pathogen-dominated ecosystems and the subsequent complications associated with microbial dysbiosis. Given the widespread implications of disrupted microbial balance on disease progression, our review also presents the temporal landscape of airway microbiome changes, including age-related microbial succession patterns, and explores the underlying mechanisms driving these ecological shifts. The progressive nature of microbial simplification frequently leads to treatment challenges, emphasizing the importance of investigating microbiome-targeted therapeutic interventions. Therefore, in this review, we also explore established therapeutic strategies, including CFTR modulators and probiotics, which could offer promising approaches to maintaining microbial balance and improving outcomes in pediatric CF patients.

Chronic kidney disease is a really important heath issue, and transplantation is an intervention that can greatly increase patient quality of life and survival. The aim of this study was to perform a comprehensive evaluation of the BK virus, CMV, and EBV in kidney transplant recipients (KTRs); to assess the prevalence of infections; and to test if our detection method would be feasible for use in follow-ups with KTRs. A total of 157 KTRs registered at the Clinical Hospital “Dr. C. I. Parhon”, Iași, Romania, were selected using specific inclusion/exclusion criteria. We tested the blood samples from each patient for BK, EBV, and CMV using a multiplex real-time PCR (qPCR) assay and the TaqMan PCR principle. The highest prevalence was detected for BKV (11/157, 7%), followed by CMV (9/157, 5.7%) and EBV (5/157, 3.2%). By simultaneously detecting three possible nephropathic viruses and oncogenes in KTRs using multiplex real-time PCR, we aimed to optimize their monitoring and follow-up. The prevalence of the tested nephropathogenic viruses—BKV, CMV, and EBV—was comparable to that analyzed in other studies. We demonstrate that the use of qPCR for viral detection in KTRs is a robust, cost-effective method for case monitoring.