Search Results (1,357)

Background: Acinetobacter baumannii and Klebsiella pneumoniae are important causes of hospital-acquired infections in pediatric patients, but comparative data on their clinical manifestations and inflammatory biomarkers remain limited. Methods: We retrospectively analyzed 55 children with single-positive blood cultures for A. baumannii (n = 20) or K. pneumoniae (n = 35), together with 30 healthy controls. Results: CRP, IL-6, and IL-10 were higher in infected children than in healthy controls. Logistic regression identified CRP and the IL-6/IL-10 ratio as exploratory correlates of infection. In ROC analyses distinguishing infected children from healthy controls, IL-6 showed the highest AUC, followed by IL-10 and CRP. In pathogen-level analyses, the IL-6/IL-10 ratio and lipase showed exploratory discriminatory signals. Conclusions: In this small retrospective case–control cohort, CRP, IL-6, and IL-10 were associated with microbiologically confirmed infection. Lipase may represent a potential biomarker for differentiating A. baumannii from K. pneumoniae infection, but its clinical utility requires prospective validation in larger multicenter cohorts using clinically relevant inpatient control groups. Full article

Acinetobacter baumannii, a Gram-negative opportunistic bacterium in the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, A. baumannii, Pseudomonas aeruginosa and Enterobacter spp.), has emerged as a leading cause of nosocomial infections worldwide. It is known to possess diverse virulence traits and antimicrobial resistance, making it a critical priority pathogen on the World Health Organization’s 2024 Bacterial Priority Pathogens List. Carbapenem-resistant A. baumannii (CRAB) is currently endemic across several continents, with global carbapenem resistance exceeding 70% in healthcare settings and multidrug-resistant infections being associated with alarming mortality rates. This review comprehensively discusses the molecular underpinnings of A. baumannii pathogenesis and virulence, detailing the array of factors coordinated by complex regulatory networks. The convergence of this pathogen’s virulence and antimicrobial resistance traits, resulting in multidrug resistance, leaves clinicians with only a handful of therapeutic options. The review also discusses upcoming therapeutic strategies, including phage therapy, antimicrobial peptides, monoclonal antibodies, photodynamic therapy, and vaccine candidates in the pipeline. While emerging therapeutics show promise, several challenges remain, and integrated approaches are warranted to efficiently combat A. baumannii’s virulence and resistance armamentarium. Full article

Staphylococcus aureus (S. aureus), a leading cause of nosocomial infections, contributes significantly to increased morbidity and mortality, especially when it forms biofilms on medical devices. This pathogen, specifically methicillin-resistant S. aureus (MRSA), remains a challenge to treat due to its ability to form biofilms and rapidly develop resistance against antibiotics. Biofilm formation allows bacteria to adhere to biotic and abiotic surfaces, creating a protective matrix that shields them from immune responses and antibiotic therapies. The widespread prevalence of multidrug-resistant S. aureus biofilms poses a significant therapeutic challenge in clinical settings. Several novel therapeutic strategies have been developed to combat S. aureus biofilm-associated infections. Accumulating evidence suggests that natural plants and their derivatives possess antimicrobial and chemo preventive properties that can disrupt established biofilms. Several plant-derived compounds with anti-biofilm activities have been reported to target the regulatory proteins involved in the Agr quorum sensing (Agr-QS) system, underscoring their potential as therapeutic candidates for the prevention and treatment of biofilm-associated infections. However, despite these encouraging findings, clinical validation of these plant-based agents is essential to ensure their efficacy, safety, and optimal application in treating S. aureus biofilm infections. The continued exploration of natural biofilm inhibitors anticipates the urgent need for new treatments to combat biofilm-associated infections and multidrug-resistant pathogens like MRSA. This review provides a detailed overview of preventive and therapeutic interventions to eradicate biofilm-forming S. aureus infections. Full article

Acinetobacter baumannii is a formidable nosocomial pathogen responsible for severe hospital-acquired infections. This study aimed to investigate the relationship between genotypic and phenotypic resistance profiles in 36 non-duplicate invasive A. baumannii isolates collected at a tertiary care hospital in Bulgaria over a six-year period (2019–2024). Identification was performed by MALDI-TOF MS and PCR-based detection of bla_OXA-51-like and gyrB. Antimicrobial susceptibility testing to ten agents was performed by gradient diffusion and broth microdilution, and selected resistance genes were detected by conventional PCR. Whole-genome sequencing of 17 representative isolates was conducted to confirm the resistance genotype–phenotype associations and perform MLST. Carbapenem resistance was detected in 34/36 isolates (94.4%), mediated by bla_OXA-23-like (29/34) or bla_OXA-72 (5/34). The armA gene associated with high-level resistance to all three aminoglycosides was identified exclusively in bla_OXA-23-like-positive isolates (18/29). In armA-negative isolates, gentamicin and tobramycin MICs decreased markedly, whereas amikacin MICs remained elevated. In addition, minocycline MICs ≥ 8 mg/L were observed in the presence of armA. Seven distinct genotypic–phenotypic profiles were defined based on these gene–MIC associations. Resistome and phylogenetic analyses confirmed these relationships, with MLST assigning the isolates to established clonal lineages ST2 and ST636 (International Clone II). These findings support the use of targeted genes, such as armA, combined with phenotypic testing to guide empirical therapy and strengthen local surveillance of high-risk A. baumannii clones in hospital settings. Full article

Nosocomial bronchopneumonia is a severe lung infection that develops more than 48 h after hospital admission and is frequently caused by antibiotic-resistant bacteria. It is often identified postmortem in forensic practice, particularly in patients with severe traumatic injuries requiring prolonged hospitalization and immobilization. Diagnosis is typically based on macroscopic findings and histopathological examination of lung tissue. This study aimed to evaluate the diagnostic value of postmortem microbiological testing by comparison with antemortem microbiological data. Ten patients with a clinical diagnosis of nosocomial bronchopneumonia were selected from forensic cases. During autopsy, tracheal swabs and lung tissue samples were collected and subjected to culture-based and molecular analyses. The results were compared with those obtained from antemortem microbiological investigations. Pathogens characteristic of nosocomial infections were identified; however, concordance with in-hospital microbiological data was highest when using next-generation sequencing (NGS) metagenomic analysis. Tracheal swab culture appears to have limited reliability for postmortem identification of bacterial agents in healthcare-associated bronchopneumonia. In contrast, metagenomic next-generation sequencing (mNGS) of lung tissue obtained at autopsy showed the highest concordance with antemortem microbiological findings and may provide valuable complementary diagnostic information, particularly in polymicrobial infections. Full article

Vancomycin-resistant enterococci (VRE) have emerged as major nosocomial pathogens worldwide, primarily due to the acquisition of the vanA gene, which confers high-level resistance to vancomycin. Rapid detection of the vanA gene, which is associated with vancomycin resistance, is crucial for timely clinical management and infection control. Through this research, we aimed to develop an assay combining loop-mediated isothermal amplification and a lateral flow Dipstick (LAMP-LFD) for the rapid detection of the vanA gene in VRE. Genomic DNA was extracted and amplified from 100 clinical urine samples by LAMP targeting vanA under optimized, constant-temperature conditions, with the amplified product then detected using a lateral flow Dipstick assay based on probe pairing. The diagnostic performance of the LAMP-LFD method was evaluated and compared with a conventional PCR reference method. The LAMP-LFD assay successfully detected the vanA gene in all positive samples, with negative samples showing no assay cross-reactivity with 12 species of bacteria commonly found in clinical settings. The developed LAMP–LFD assay showed promising diagnostic performance for detecting the vanA gene in Enterococcus isolates, demonstrating complete agreement with the reference PCR method in this study. Owing to its rapid turnaround time, simplicity, and visual readout, the assay has potential as a molecular screening tool for VRE. However, further validation in larger, multicenter studies and comparison with phenotypic antimicrobial susceptibility testing are required before routine clinical implementation. Full article

Multidrug-resistant (MDR) Klebsiella pneumoniae is a critical cause of nosocomial infections associated with high mortality. Of particular concern is the genomic convergence of multidrug resistance and hypervirulence (MDR-hvKP), which represents a severe public health threat. This study characterised the resistome, virulome, and population structure of seven clinical MDR K. pneumoniae isolates collected between 2024 and 2025 across four Peruvian regions (Moquegua, Ucayali, Loreto, and Lima) using whole-genome sequencing (WGS). Genomic analysis identified six distinct sequence types, with the high-risk clone ST307 being the most prevalent (2/7 isolates), consistently associated with the KL102 capsular locus. Remarkably, one isolate from Loreto (oph_54) exhibited a convergent MDR-hvKP genomic profile (ST218, KL57, virulence score 4), carrying yersiniabactin, salmochelin (iro), and aerobactin (iuc) loci alongside multiple resistance determinants. The isolates presented a robust resistome dominated by the extended-spectrum beta-lactamase gene bla_CTX-M-15 (5/7) and bla_OXA-1, coupled with aac(6′)-Ib-cr and fosA6 genes. Plasmid analysis revealed a predominance of IncFIB(K) replicons. Although exploratory, these findings demonstrate the regional presence of high-risk ST307 lineages and the emergence of convergent MDR-hvKP genomic profiles within the analysed Peruvian hospitals. Immediate and continuous genomic surveillance is urgently required to monitor the potential spread of these highly dangerous, MDR bacterial lineages within these healthcare environments. Full article

Elizabethkingia species have emerged as important nosocomial pathogens associated with multidrug resistance and persistent infections. This study aimed to characterize clinical Elizabethkingia isolates from Northern Thailand regarding antimicrobial susceptibility, virulence-associated phenotypes, and biofilm formation, and to evaluate the antimicrobial and anti-biofilm activity of dialdehyde cellulose (DAC) film. A total of 49 clinical isolates were identified by MALDI-TOF mass spectrometry, with species identification confirmed by 16S rRNA gene sequencing. Antimicrobial susceptibility was determined against 12 agents. Virulence traits (protease, lipase, lecithinase, and hemolysin production) and biofilm formation were assessed using standard phenotypic assays. DAC films were evaluated against selected resistant isolates. Elizabethkingia anophelis predominated, and most isolates exhibited multidrug or extensive drug resistance, with high resistance to carbapenems and cephalosporins. Piperacillin–tazobactam, levofloxacin, and trimethoprim–sulfamethoxazole showed the greatest activity. All isolates demonstrated protease production and time-dependent hemolysis, while lipase and lecithinase activities were absent. Biofilm formation varied among isolates, while DAC films inhibited bacterial growth and prevented detectable biofilm formation in the tested isolates. No significant difference was observed between DAC and DAC supplemented with meropenem in inhibition zone diameters (p = 0.555). Clinical Elizabethkingia isolates demonstrated extensive antimicrobial resistance with conserved virulence traits and heterogeneous biofilm formation. DAC films demonstrated antimicrobial activity and prevented detectable biofilm formation under the experimental conditions. Further studies are warranted to evaluate their mechanism of action and potential applications. Full article

Background: International evidence supports early initiation of ceftazidime-avibactam (CAZ-AVI) in carbapenem-resistant Enterobacterales (CRE) infections, with superior outcomes when therapy is initiated within 72 h. The applicability of this principle to the United Arab Emirates (UAE) requires contextualization against local antimicrobial resistance epidemiology. Methods: This consensus narrative review integrates two evidence streams: (1) national AMR surveillance data from the UAE National Antimicrobial Resistance Surveillance Report 2024—encompassing 195,108 non-duplicate isolates from 318 surveillance sites across all seven Emirates—providing phenotypic susceptibility and resistance rates for key gram-negative pathogens; and (2) a structured review of the published international evidence base on CAZ-AVI clinical efficacy, outcome data, and timing, identified through PubMed searches using the terms “ceftazidime-avibactam”, “empiric therapy”, “carbapenem-resistant Enterobacterales”, and “nosocomial infections”. The risk-stratification framework was developed through expert consensus by the authoring group, informed by the integrated evidence synthesis and structured around established clinical risk factors for carbapenem-resistant gram-negative infection. Results: National carbapenem resistance among Enterobacterales remains low (imipenem 3.4%R; meropenem 1.4%R), with Klebsiella pneumoniae exhibiting the highest carbapenem non-susceptibility (imipenem 5.8% NS; meropenem 2.8% NS). Direct CAZ-AVI susceptibility testing data were available only for Pseudomonas aeruginosa at the emirate level, showing consistently high susceptibility (88–93% across Abu Dhabi, Dubai, and the Northern Emirates); dedicated CAZ-AVI susceptibility data for Klebsiella pneumoniae and Escherichia coli were not reported in any emirate-level antibiogram, representing a significant national surveillance gap. The absence of carbapenemase genotype data (OXA-48 versus NDM/MBL) in the national surveillance dataset is identified as a further critical gap. Conclusions: CAZ-AVI is not supported as a universal empiric therapy for all nosocomial pneumonia in the UAE. A risk-stratified approach is proposed: standard anti-pseudomonal beta-lactams for general nosocomial infections, and early CAZ-AVI for pre-defined high-risk CRE-suspected patients, where the timing benefit is operationally justified primarily by the international outcome evidence, given that UAE-specific CAZ-AVI phenotypic data are currently available only for P. aeruginosa. Investment in carbapenemase molecular surveillance and expanded CAZ-AVI susceptibility reporting is recommended as a national priority to enable precise empiric prescribing. Full article

Coagulase-negative staphylococci (CoNSs) are major opportunistic pathogens in healthcare settings, particularly affecting immunocompromised patients and those with indwelling medical devices. Their growing antimicrobial resistance and ability to form biofilms present significant therapeutic challenges. This study analyzed 148 clinical CoNS isolates to determine species distribution, antimicrobial resistance, resistance genes, and biofilm production. Staphylococcus epidermidis was the most prevalent species (49.3%), followed by Staphylococcus hominis (27.0%) and Staphylococcus capitis (6.8%). Penicillin (83.8%), erythromycin (72.3%), and cefoxitin (66.2%) showed the highest resistance rates. Notably, 60.8% of isolates were resistant to fusidic acid and 45.3% to clindamycin, with inducible resistance in 12.1%. Among aminoglycosides, tobramycin resistance (45.3%) was most frequent. Resistance to ciprofloxacin and trimethoprim–sulfamethoxazole reached 45.9%, while mupirocin resistance was 17.6%. Among isolates resistant to penicillin and/or cefoxitin (n = 128), the mecA gene was detected in 69.5%; the mecC gene was absent. Only 38.5%% of mupirocin-resistant isolates carried the mupA gene. Trimethoprim resistance was mainly associated with dfrA (60.3%) and dfrG (14.7%). Biofilm super-producers accounted for 64.9% of isolates and non-producers for 7.4%, with no significant link between biofilm formation and antibiotic resistance. These findings reinforce the clinical relevance of multidrug-resistant, mupirocin-resistant, and biofilm-forming CoNSs, underscoring the need for improved surveillance and infection control. Full article

Background/Objectives: Clostridioides difficile infection (CDI) is an increasingly recognised nosocomial complication in patients hospitalised with coronavirus disease 2019 (COVID-19), driven by broad-spectrum antibiotic exposure, corticosteroid use, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related intestinal dysbiosis. The contribution of underlying cardiovascular comorbidities, particularly heart failure, to CDI susceptibility in hospitalised COVID-19 patients remains insufficiently characterised. We aimed to evaluate the prevalence, risk factors, and clinical impact of CDI in hospitalised COVID-19 patients at a tertiary Romanian infectious diseases centre, with a specific focus on cardiovascular disease and modifiable antimicrobial-prescribing factors. Methods: This single-centre retrospective observational cohort study enrolled 395 consecutive adult patients hospitalised with SARS-CoV-2 infection confirmed by reverse transcription polymerase chain reaction (RT-PCR) at the “Victor Babeș” Clinical Hospital for Infectious Diseases and Pneumophthisiology, Timișoara, Romania, between 1 March 2020 and 31 December 2024. Patients were stratified into a CDI group (n = 24) and a non-CDI group (n = 371) on the basis of hospital-onset CDI. Demographic, clinical, laboratory, therapeutic, and outcome variables were extracted from electronic medical records. Continuous variables were compared using Student’s independent-samples t-test, categorical variables using Fisher’s exact test; odds ratios (ORs) with exact 95% confidence intervals (CIs) were computed for all binary comparisons, and a parsimonious multivariable logistic regression was used to adjust the antibiotic-exposure effect for age. Temporal relationships between CDI onset and sepsis documentation were also analysed. A two-sided p-value < 0.05 was considered statistically significant. Results: CDI was identified in 24 patients (prevalence 6.1%). The CDI and non-CDI groups were comparable in age (71.1 ± 10.2 vs. 71.7 ± 11.4 years; p = 0.817), sex distribution (50.0% vs. 45.8% female; p = 0.833), and vaccination status (p = 0.383). Heart failure prevalence did not differ between groups (29.2% vs. 26.7%; OR 1.13, 95% CI 0.46–2.81; p = 0.813). Any antibiotic therapy was strongly associated with CDI (95.8% vs. 70.6%; OR 9.57, 95% CI 1.28–71.74; p = 0.004), as was longer duration of antibiotic therapy (8.1 ± 2.2 vs. 5.2 ± 3.7 days; p < 0.001). In the multivariable model, each additional day of antibiotic therapy was independently associated with a 13.6% increase in the odds of CDI (adjusted OR 1.14 per day, 95% CI 1.03–1.26; p = 0.013) after adjustment for age. Piperacillin/tazobactam accounted for 65.2% (15/23) of the recorded pre-CDI broad-spectrum antibiotic regimens among antibiotic-exposed CDI patients. Documented sepsis was substantially more frequent in CDI patients (95.8% vs. 15.4%; p < 0.001) and length of hospitalisation was prolonged (15.6 ± 8.2 vs. 12.0 ± 8.1 days; p = 0.038). In-hospital mortality did not differ significantly (4.2% vs. 7.5%; p = 1.000). Conclusions: Hospital-onset CDI complicated 6.1% of hospitalised COVID-19 admissions and was independently associated with the cumulative duration of antibiotic therapy. Heart failure was not significantly associated with CDI in this cohort; however, given the limited number of CDI events, this should be interpreted as absence of evidence rather than evidence of absence. CDI was also associated with prolonged hospitalisation and high co-occurrence of documented sepsis, although causality cannot be inferred from the retrospective design. These findings support strengthened antibiotic stewardship and targeted CDI surveillance in COVID-19 inpatient wards. Full article

Background: Trichosporon asahii is an emerging opportunistic yeast of growing concern in nosocomial settings, particularly in immunocompromised critically ill patients. Outbreaks in intensive care units remain infrequently reported, and environmental reservoirs are seldom fully characterized. Methods: A prospective outbreak investigation was conducted from 16 August to 29 October 2024 at a 496-bed high-complexity university hospital in Cali, Colombia. Case definitions distinguished healthcare-associated infection (HCAI) from colonization. Active surveillance included clinical cultures, environmental sampling of surfaces, biomedical equipment, and air conditioning duct systems. Microbiological identification was performed using MALDI-ToF mass spectrometry. Results: Nine cases were identified among 74 patients (6.76% attack rate); five were HCAIs, and four were colonizations. Overall mortality was 44%, though 0% was attributable to T. asahii. Primary risk factors included prolonged hospitalization, invasive devices, and broad-spectrum antibiotics. While environmental cultures were negative, maintenance records revealed unscheduled air duct cleaning and intermittent AC failures in the affected unit. Conclusions: Epidemiological evidence suggests that air conditioning malfunctions and temperature fluctuations facilitated fungal dispersal. The outbreak was contained through unit closure, hydrogen peroxide vaporization, and reinforced hand hygiene, highlighting the necessity of rigorous ventilation maintenance in high-complexity units. Full article

Serratia species are Gram-negative pathogens responsible for a wide range of nosocomial infections. This multicenter nationwide retrospective study aimed to describe the epidemiology, clinical characteristics, antimicrobial susceptibility, and outcomes of Serratia infections in pediatric oncology patients and hematopoietic stem cell transplantation (HSCT) recipients in Poland between 2012 and 2023. A total of 36 Serratia infection episodes were identified in patients under 20 years of age, including 30 cases (83.3%) in the oncological (OHD) group and six (16.7%) among HSCT recipients. The median age was 4.30 years. The most common underlying diseases were acute lymphoblastic leukemia (36.1%) and central nervous system tumors (16.7%). Bloodstream infections predominated in OHD patients (33.3%), whereas urinary tract infections were most frequent in HSCT recipients (83.3%). S. marcescens was the most commonly isolated species. More than half of isolates (53.3%) showed antimicrobial resistance, with extended-spectrum β-lactamase (ESBL)-producing strains in 26.7% and AmpC β-lactamase-producing strains in 13.3%. Multidrug resistance occurred in 30%. Treatment most often included amikacin, piperacillin/tazobactam, and carbapenems. Five deaths occurred in the OHD group and one in the HSCT group, none directly related to Serratia infection. Although uncommon, Serratia infections remain clinically relevant due to their high antimicrobial resistance, underscoring the need for antimicrobial stewardship. Full article

Background: Early detection of severe infections in burn patients is difficult due to confounding sterile inflammation. Previous research has shown that Pancreatic Stone Protein (PSP) is less affected by trauma and surgery. Therefore, this study investigated whether longitudinal PSP trends can distinguish sterile post-burn inflammation from clinically relevant infections and indicate response to antimicrobial therapy. Methods: This prospective pilot cohort study included 10 consecutive adult patients with moderate to severe burn injuries admitted to a specialized burn intensive care unit. PSP levels were measured using bedside testing (abioSCOPE^®) daily over a 14-day observation period. Clinical parameters, burn severity as assessed by the Abbreviated Burn Severity Index (ABSI), and the occurrence of severe infectious complications, including pneumonia and bacteremia, were systematically recorded. PSP measurements were not used to guide clinical decision-making. Results: Patients who developed severe infectious complications (pneumonia and/or bacteremia; mean ABSI 8.5) showed a consistent and characteristic increase in PSP levels (>350 ng/mL) over time, with elevations preceding the clinical diagnosis of infection (24–120 h). In contrast, patients without pneumonia or bacteremia (mean ABSI 6) exhibited low and stable PSP (<150 ng/mL) concentrations throughout the observation period, despite the presence of burn-related injury and the expected sterile inflammatory response. Conclusions: In this exploratory cohort study distinct PSP trajectory patterns, with persistently low levels in non-infected patients and rising levels preceding clinically diagnosed infection in several cases, were observed. These preliminary findings suggest that longitudinal PSP monitoring may provide potential utility for infection surveillance in burn ICU patients. However, due to the exploratory design and very limited sample size, the findings should be interpreted cautiously and require validation in larger prospective multicenter studies before conclusions regarding clinical decision-making or patient outcomes can be drawn. Full article

Serratia marcescens is a nosocomial pathogen that has acquired resistance to multiple antibiotics, necessitating alternative antimicrobial strategies. The aim of this study was to isolate and characterize a novel phage (ØAS2) against Serratia marcescens and evaluate its biocontrol potential in dairy matrices. In this study, a lytic bacteriophage specific to S. marcescens, designated ØAS2, was isolated from sewage samples collected in Assiut, Egypt. Phage ØAS2 was characterized using plaque assays, transmission electron microscopy (TEM), host range determination, pH and thermal stability tests, and one-step growth curve analysis. Its ability to inhibit bacterial growth and disrupt biofilms was also evaluated in vitro. TEM revealed that ØAS2 possesses an icosahedral head approximately 47.2 nm in diameter and a very short tail, consistent with the morphology of a member of the class Caudoviricetes that exhibits podovirus-like morphology. The phage exhibited a broad host range, infecting various Serratia strains as well as other Gram-negative bacteria, including Klebsiella spp., Escherichia coli, Salmonella typhi, and Shigella spp. ØAS2 was thermostable up to 60 °C and showed maximum activity at pH 8. One-step growth curve analysis revealed a short latent period of 10 min and a burst size of 115 PFU per infected cell. ØAS2 effectively inhibited the growth of S. marcescens SM02 in vitro and significantly reduced preformed biofilms at different multiplicities of infection (MOIs). When applied to skim milk and fresh soft cheese at various MOIs (Multiplicities of Infection), the phage successfully controlled bacterial contamination under refrigerated storage (7 °C for 7–10 days). At MOI 5.0, phage ØAS2 reduced biofilm biomass by 25.6%, planktonic growth by 85.7%, and achieved a reduction of 2.1 log₁₀ CFU/mL in skim milk. These findings indicate that ØAS2 is a promising biocontrol candidate for managing S. marcescens spoilage in dairy products. Full article