Search Results (308)

Background: Pseudomonas aeruginosa is one of the leading agents causing healthcare-associated infections (HAIs) due to its intrinsic resistance, its capacity to acquire resistance mechanisms, and its persistence in hospital environments. In Mexico, it ranks among the most frequently reported pathogens in national surveillance systems. The aim of this study was to characterize antimicrobial resistance profiles and the genetic determinants associated with MDR/XDR phenotypes in P. aeruginosa strains from HAIs at Hospital Juárez de México (HJM). Methods: Sixty-three strains from patients with HAIs were analyzed. Identification was confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility testing followed CLSI guidelines. MDR/XDR phenotypes were classified according to the Latin American consensus for categorizing MDR, XDR, and PDR pathogens. Screening for resistance mechanisms was carried out by PCR for the main β-lactamases circulating at HJM. Finally, mutations in the oprD gene were detected in imipenem-resistant isolates through amino acid sequence alignment. Results: Resistant phenotypes allowed the identification of MDR and XDR profiles. Only the metallo-β-lactamase bla_VIM was detected. Analysis of oprD porin sequences revealed recurrent mutations (S103T, T115K, L170F, G186P, and T189V) associated with imipenem resistance. Conclusions: In P. aeruginosa, the presence of bla_VIM and structural alterations in OprD confirms the multifactorial nature of carbapenem resistance. These findings underscore the need to strengthen microbiological surveillance programs and antimicrobial stewardship strategies to mitigate the impact and spread of MDR/XDR isolates. Full article

Recycled wastewater is vital for the circular economy, especially on water-scarce islands. This study explored the presence of Carbapenem-Resistant Enterobacterales and other emerging pathogens in irrigation water on four Canarian Islands, applying a One Health perspective. Using membrane filtration and MALDI-TOF mass spectrometry, 69 bacterial isolates were identified. The findings revealed that 78% were Gram-negative bacilli like Pseudomonas aeruginosa, Acinetobacter spp., Enterobacteriaceae, etc., while 22% were Gram-positive bacteria, including Enterococcus spp. The main mechanisms of carbapenem resistance in Pseudomonas spp. and Acinetobacter spp. were oxacillinases, followed by metallo-β-lactamases (MBL). In Enterobacteriaceae, characterization of carbapenemase types was less frequent, with oxacillinase 48 (OXA-48) being the most prevalent. The detection of multidrug-resistant organisms in recycled wastewater highlights an urgent need for routine microbiological monitoring in water management to protect both public health and agricultural sustainability. Full article

Antimicrobial resistance in urinary tract infections (UTIs) poses a critical public health challenge, yet comparative data between outpatient and inpatient settings remain limited, particularly in Latin America. This study characterized the epidemiology, microbiology, and resistance patterns of UTIs in northwestern Mexico. A retrospective analysis of 1041 patients with UTI (May–November 2024) was conducted. Microorganism identification and antimicrobial susceptibility were determined using the MicroScan WalkAway system in accordance with CLSI guidelines. Results: Outpatients accounted for 80.5% of cases and inpatients for 19.4%, with a 3.1% mortality rate. Escherichia coli predominated (62.9%), with a significant association with outpatients (p = 0.02), whereas Enterobacter cloacae, Acinetobacter spp., Candida tropicalis, and C. albicans were associated with inpatients (p < 0.05). Pediatric patients exhibited distinctive microbiological profiles: Pseudomonas aeruginosa (9.7% vs. 2.1%, p = 0.032), Enterococcus faecalis (33.3% vs. 16.2%, p = 0.001), and Staphylococcus epidermidis (26.6% vs. 6.5%, p = 0.027) were significantly more prevalent than in adults. Multidrug resistance (MDR) was detected in 27.1% of isolates, and extensive drug resistance (XDR) in 3.2%. XDR was associated with Gram-positive bacteria (12.2% vs. 1.4%, p < 0.001). Carbapenem-resistant Enterobacteriaceae (CRE) were identified in 0.9% (7/772) of cases, with 42.9% occurring in outpatients. Hospitalization (OR: 2.01; 95% CI: 1.43–2.83), surgical services (OR: 1.41; 95% CI: 1.02–1.97), and recent surgery (OR: 2.37; 95% CI: 1.04–5.39) were independent predictors of MDR/XDR infections. Conclusions: These findings demonstrate the emergence of CRE within the community and distinctive pediatric resistance patterns, underscoring the need for tailored antimicrobial stewardship strategies in this region. Full article

Acinetobacter baumannii has been characterized by CDC, WHO and most National Healthcare Systems worldwide as a critical nosocomial pathogen, and classified as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) pathogen. Mortality of invasive infections due to A. baumannii exceeds 40%. To highlight its impact on public health, ECDC has organized a special project on national lab co-ordination to accurately detect and report carbapenem-resistant strains, to identify epidemiological factors for infection (or colonization) with carbapenem-resistant A. baumanii at clonal and sub-genomic level. This review aims to describe the history, epidemiology, and evolution of resistance of A. baumannii, and stress the caveats associated with the management of systemic infections. Available active antimicrobials and drugs in the pipeline are listed, and available clinical evidence on their pharmacokinetics and efficacy in various types of infections are described. Clinician’s choice of treatment (drug, and monotherapy vs. combination treatment) depends on the patients’ profile, site of infection and antimicrobial resistance profile. Emphasis is laid on specific patient subpopulations, whose management is discussed. Full article

Emerging antimicrobial resistance (AMR) in companion animals represents a global health concern as they serve as potential reservoirs for multidrug-resistant (MDR) bacteria, which can be transmitted to humans. Herein, we provide comprehensive surveillance data on resistance patterns in veterinary hospital settings, focusing on urinary tract infection. A total of 23 bacterial strains were isolated from urine specimens of hospitalized companion animals suspected of urinary tract infections (UTIs) between 2022 and 2024. 16S rRNA sequencing analysis revealed that Escherichia coli (47.8%), Klebsiella pneumoniae (21.7%), and Pseudomonas aeruginosa (8.7%) were predominant uropathogens. Minimum inhibitory concentration and minimum bactericidal concentration tests were employed to analyze AMR patterns across different classes of antibiotics. Moreover, antimicrobial susceptibility test exhibited 73.91% MDR according to the standard definition given by the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines. Most Gram-negative bacteria have been shown to be resistant to beta-lactam antibiotics, especially carbapenems. Notably, an E. coli strain was confirmed to possess the bla_NDM-1 gene encoding the carbapenemase New Delhi metallo-β-lactamase. These findings support the implementation of targeted infection control measures and evidence-based treatment protocols to preserve antimicrobial efficacy in companion animal medicine to minimize potential public health risks through the One Health approach. Full article

Pseudomonas aeruginosa bloodstream infections (PABSIs) are a major clinical challenge due to their association with significant mortality and antimicrobial resistance mechanisms. The COVID-19 pandemic changed antimicrobial practices, intensive care management, and patient risk profiles, potentially influencing the epidemiology and outcomes of PABSIs. In the post-pandemic period, practices were expected to revert to normal. The objective of this scoping review was to identify and summarize reported mortality rates and risk factors for PABSIs in studies published between 2023 and 2025. Literature searches were conducted across PubMed, Web of Science, Embase, and Scopus. Screening was performed in accordance with PRISMA-ScR guidelines. Twenty-two eligible studies were included. Mortality rates varied across the study setting and populations; however, several consistent predictors were consistently identified, including carbapenem exposure, multidrug-resistant Pseudomonas aeruginosa, hematologic disease or malignancy, corticosteroid therapy, sepsis or septic shock, mechanical ventilation, and higher severity-of-illness scores. Few studies have linked molecular mechanisms to patient outcomes, highlighting important gaps in knowledge. Notably, only a small number of studies included the post-pandemic period but did not analyze the data separately. Despite limited available evidence, critically ill and immunocompromised patients remain at greatest risk of death from PABSIs. This review highlights the need for a broader comparative analysis in future. Full article

Background/Objectives: Metallo-β-lactamase (MBL)-producing Gram-negative bacteria represent a growing global health threat due to their broad resistance to β-lactam antibiotics, including carbapenems, which severely limits treatment options. This study aimed to evaluate the in vitro synergistic activity of fosfomycin (FOS) in combination with selected older and newer antimicrobials against MBL-producing Klebsiella pneumoniae and Pseudomonas aeruginosa. Methods: Synergistic interactions were assessed using agar dilution checkerboard on 42 MBL-producing clinical isolates (22 K. pneumoniae, 20 P. aeruginosa) and confirmed using time-kill assays with selected isolates. FOS was tested in combination with colistin (COL), ceftazidime–avibactam (CAZ-AVI), meropenem (MER), amikacin (AMI), aztreonam (AZT), aztreonam–avibactam (AZT-AVI), or cefiderocol (FDC). Results: Most FOS combinations exhibited additive or synergistic effects against clinical isolates. Synergy rates reached 72.7% for the FOS+CAZ-AVI combination (K. pneumoniae) and 65.0% for the FOS+COL combination (P. aeruginosa). An asymmetric synergistic interaction was identified for FOS+CAZ-AVI, with FOS enhancing the activity of CAZ-AVI more markedly than vice versa, especially in K. pneumoniae. Time-kill assays on selected isolates confirmed synergistic and bactericidal activity of FOS+CAZ-AVI and FOS+COL, and showed that bacterial regrowth observed with FOS, CAZ-AVI, and COL alone was suppressed in combination therapy. Conclusions: FOS-based combinations, particularly with CAZ-AVI and COL, demonstrated potent synergistic activity against MBL-producing K. pneumoniae and P. aeruginosa, supporting their potential utility in rational combination therapies for infections due to MBL-producing bacteria. Full article

Antimicrobial resistance (AMR) is a global health threat, increasing morbidity, mortality, and healthcare costs. Multi-drug resistant ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae) cause most hospital-acquired infections. Local data on their resistance profiles remain limited in low-income settings. This study assessed the prevalence and resistance patterns of ESKAPE pathogens isolated from clinical specimens at Rwanda Military Referral and Teaching Hospital. A descriptive cross-sectional study was conducted from June 2022 to January 2023. ESKAPE isolates were identified and tested for antimicrobial susceptibility using the BD Phoenix M50 System. Data on sample type, ward, and demographics were analyzed. Of 744 bacterial findings, 207 (30%) were ESKAPE isolates. After excluding duplicates and non-recovered isolates, 156 were identified as ESKAPE. K. pneumoniae was most common (41%), followed by S. aureus (27%), A. baumannii (13%), P. aeruginosa (11%), and E. cloacae (8%); no E. faecium was detected. Among Gram-negatives, 63% were resistant to third-generation cephalosporins and 32% to carbapenems, with A. baumannii showing highest resistance (85% and 75%). Methicillin-Resistance in Staphylococcus aureus (MRSA) was 7%. This first hospital-based study in Rwanda shows high cephalosporin and carbapenem resistance, highlighting the need to strengthen diagnostics and stewardship. Full article

Multi-drug-resistant Pseudomonas aeruginosa (P. aeruginosa) commonly causes infections that are difficult to treat, necessitating the development of new therapeutics. The search for more effective ways to combat the emergence of bacterial resistance has also led to research into phage-antibiotic synergy (PAS) as a potential therapeutic strategy. The aim of this study was to isolate and characterize virulent phages from water sources that are active against clinical carbapenem-resistant P. aeruginosa isolates, and to evaluate their in vivo efficacy using a Galleria mellonella larvae infection model. The biological and genomic characteristics of the isolated phages were determined using host range analysis, one-step growth curve analysis, transmission electron microscopy analysis and whole-genome sequencing. Two phages (vB_PaMB13 and vB_PaMB17) that demonstrated in vitro synergistic and bactericidal interactions with antipseudomonal antibiotics (tobramycin and ceftazidime) were selected for further investigation using the checkerboard method. The study revealed synergy between all phages and either antibiotic, tobramycin or ceftazidime, against P. aeruginosa. Similarly, the percentage survival rates increased in the in vivo model when both phages and antibiotics were used in combination. Overall, our study provides further support for the idea that phage-antibiotic synergy could be an effective strategy for improving treatment outcomes. Full article

Background: Biliary peritonitis is a severe intra-abdominal emergency with high mortality. Effective management requires source control and appropriate antimicrobial therapy. Methods: This review synthesizes recent literature (2016–2025), as well as established guidelines recommendations on the evolving microbiology and antimicrobial resistance patterns in biliary tract infections, as data on biliary peritonitis is scarce and relatively heterogeneous. Results: The microbiological landscape is stratified by patient history. Community-acquired infections are typically caused by Escherichia coli, Klebsiella pneumoniae, and Enterococcus spp. In contrast, healthcare-associated infections show a shift, with highly resistant pathogens such as Pseudomonas aeruginosa, and a tendency towards polymicrobial infections. The rise of multidrug-resistant (MDR) organisms, including extended-spectrum β-lactamase (ESBL)-producing Enterobacterales, Carbapenem-Resistant Enterobacterales (CRE), and Vancomycin-Resistant Enterococci (VRE), is a critical challenge limiting therapeutic options. Resistance patterns vary geographically, necessitating the use of local data. Conclusions: This review argues for a paradigm shift from severity-based guidelines to a dual-axis model incorporating resistance risk factors (prior healthcare exposure, previous biliary interventions, a history of MDR infections). We propose a risk-stratified approach to empiric antibiotic selection, emphasizing microbiological diagnostics for therapy de-escalation. Future research should focus on prospective studies, novel antibiotics, and rapid diagnostics. Full article

Introduction: Eravacycline is a new fluorocycline antibiotic with a broad spectrum of antimicrobial activity approved for the treatment of patients with complicated intra-abdominal infections. This systematic review aimed to evaluate the published data on the resistance of Gram-negative bacterial isolates to eravacycline. Methods: We identified relevant publications by systematically searching Embase, PubMed, Scopus, and Web of Science from their inception to 29 August 2025. Published antimicrobial resistance breakpoints of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the US Food and Drug Administration (FDA) were used. Results: Data on 59,922 Gram-negative bacterial clinical isolates were retrieved from 68 articles after the screening of 283 potentially relevant studies. The resistance of consecutive (non-selected) Escherichia coli ranged from 0.9% to 9.6%. The MIC₅₀ values of eravacycline were ≤0.5 mg/L for Acinetobacter baumannii isolates, including carbapenem-resistant A. baumannii, in the majority of studies. The proportions of resistance were higher among other lactose non-fermenting Gram-negative bacterial isolates, especially Pseudomonas aeruginosa, as well as among selected E. coli with advanced patterns of antimicrobial resistance. Conclusions: The evaluated data support the adequate antimicrobial activity of eravacycline against most Gram-negative bacterial clinical isolates. However, in vitro antimicrobial susceptibility testing and modern molecular diagnostic tests, including those that examine mechanisms of resistance, are helpful for the appropriate use of eravacycline in clinical practice. Full article

Background: Carbapenem-resistant Enterobacterales and difficult-to-treat resistance (DTR) Pseudomonas aeruginosa are a growing public health issue. Cefiderocol demonstrated activity against β-lactamase-producing Gram-negative bacteria (GNB). However, bone PharmacoKinetics (PK) data is lacking. Here, we report a case of post-traumatic chronic osteomyelitis caused by extensively drug-resistant (XDR) Pseudomonas aeruginosa which was successfully treated with cefiderocol. Moreover, we conducted a non-systematic review of the available literature. Case Report: We described the case of a 64-year-old man who was admitted to a traumatology ward after a work accident caused crushing of his left foot. Microbiological tests on intraoperative biopsies demonstrated XDR P. aeruginosa and K. oxytoca. Despite the administrations of different antibiotics regimens and multiple surgical revisions, the patient developed chronic osteomyelitis. To prevent amputation, cefiderocol was prescribed for six weeks, resulting in a complete clinical resolution of osteomyelitis. Review of the Literature: We performed a non-systematic review of the literature searching the public databases PubMed and Google Scholar. We identified nine case reports. In most patients (60%) the cause of osteomyelitis was post-surgical, and all the reported cases were healthcare associated. Osteomyelitis treatment required both antimicrobial therapy and surgery in all the cases described. Cefiderocol was often prescribed in association with other antibiotics (70%). Clinical cure was described in all the reported cases. Conclusions: This study highlights that cefiderocol is safe and efficacious to treat osteomyelitis caused by carbapenem-resistant GNB. However, evidence is limited to a few case reports. Full article

Background: Increasing antimicrobial resistance (AMR) is one of the leading causes of death worldwide. The predominant pathogens that exacerbate the AMR problem are multidrug-resistant (MDR) Gram-negative bacteria (GNB). Due to the increasing adaptation of MDR GNB to commercially available antimicrobial drugs, such as carbapenems as well as third- and fourth-generation cephalosporins, pharmaceutical companies around the world have been forced to produce increasingly innovative chemotherapeutics. Cefiderocol (CFDC) is a novel injectable cephalosporin 5 generation developed by Shionogi, directed against MDR GNB, including strains resistant to carbapenems. Results: Analysis demonstrated its significant efficacy across a wide range of in vitro and in vivo studies against MDR GNB, including Carbapenem-resistant Pseudomonas aeruginosa (CRPA), Carbapenem-resistant Acinetobacter baumannii (CRAB), and carbapenem-resistant Enterobacterales (CRE) (WHO Critical Priority Pathogens). Clinical studies have shown CFDC to be an effective drug with few adverse effects. Conclusions: When used CFDC appropriately within antibiotic stewardship guidelines, this drug is an effective, well-tolerated targeted treatment option for patients with severe clinical conditions. Full article

Antibiotic-resistant microbes represent a growing problem for modern medicine and public health. Projections indicate that deaths from such infections could reach 10 million per year by 2050. Healthcare associated infections (HAI) are among the most significant causes of mortality and morbidity in hospitals, impacting millions of patients globally. The emergence of HAI is associated with resistance to antimicrobials, rapidly worsening the patient’s condition. Antimicrobial resistance determines unresponsiveness to treatment, which can ultimately lead to severe complications such as sepsis and shock. It is estimated that one in every ten patients are susceptible to infection during their stay in hospital, with the microorganism responsible for the infection frequently proving resistant to antibiotics. Among the latter, CRE (carbapenem-resistant Enterobacteriaceae), CRAB (carbapenem-resistant Acinetobacter baumannii), CRPA (carbapenem-resistant Pseudomonas aeruginosa), vancomycin-resistant Enterococcus spp. and methicillin-resistant Staphylococcus aureus (MRSA), commonly referred to as ‘superbugs’, are a major cause of HAIs. The aim of the present study is to provide a comprehensive overview of the global epidemiology of healthcare-associated infections, with particular emphasis on their incidence, distribution over time, and correlation with the socioeconomic status of different countries. Furthermore, the review aims to evaluate the effectiveness of current preventive strategies in reducing the incidence and mortality associated with HAIs. Full article

Neutropenic patients with acute myeloid leukemia (AML) are at high risk for severe, multidrug-resistant infections. Sepsis due to carbapenem-resistant Pseudomonas aeruginosa (CRPA) in this population often leads to septic shock and acute respiratory distress syndrome (ARDS), with historically poor outcomes. CytoSorb™ hemoadsorption has been proposed as an adjunctive therapy for refractory septic shock, but evidence in hematologic malignancies remains limited. This report describes a 29-year-old male with newly diagnosed AML complicated by neutropenic fever, bacteremia due to CRPA, and subsequent hospital-acquired pneumonia progressing to ARDS. Despite multiple antibiotic regimens and aggressive intensive care management, including mechanical ventilation, prone positioning, and continuous renal replacement therapy (CRRT), the patient developed refractory septic shock with persistent lactic acidosis and elevated inflammatory markers. Early adjunctive CytoSorb hemoadsorption was initiated, guided by maximal CytoScore criteria, as part of a comprehensive supportive strategy. Following CytoSorb therapy, the patient demonstrated transient hemodynamic and biochemical improvement; however, profound neutropenia and multi-organ failure persisted. Microbiological clearance of CRPA was not achieved; given confirmed colistin susceptibility and unknown carbapenemase mechanism, a salvage combination of colistin plus ceftazidime–avibactam was employed. Transient hemodynamic improvement was observed after CytoSorb initiation; however, cytokine assays were not performed, and microbiological clearance was not achieved, precluding any mechanistic attribution to CytoSorb. This case highlights the complexity of managing CRPA sepsis and ARDS in neutropenic AML patients, and the challenges in attributing observed clinical improvement to CytoSorb therapy in the context of multiple simultaneous interventions. The absence of cytokine assays (e.g., IL-6, TNF-α) precludes any mechanistic attribution of observed changes to cytokine adsorption, and interpretation should remain descriptive rather than causal. Observed transient changes occurred amid simultaneous interventions (broad-spectrum antibiotics, CRRT, prone ventilation, corticosteroids, and filgrastim), precluding attribution to any single therapy, including CytoSorb. Given the fatal outcome and persistent CRPA positivity, the clinical impact of this observation is limited, and the generalizability of a single-case report is restricted. Cautious interpretation is warranted, and CytoSorb may be considered as part of a comprehensive care bundle rather than as a standalone solution. Alternative tetracycline-based combinations were reviewed but not adopted under our center’s salvage protocol for this XDR presentation. Future studies are warranted to clarify its clinical benefit and optimal timing in this population. Full article