Search Results (126)

Ventilator-associated pneumonia (VAP) remains the most frequent ICU-acquired infection and a major driver of antimicrobial exposure. Historically, clinicians treated patients for 10–14 days or longer, particularly when multidrug-resistant organisms were suspected. Current evidence from randomized trials and meta-analyses now supports shorter-course therapy (~7 days) for most immunocompetent patients with VAP who demonstrate clinical improvement. Mortality and treatment failure are not increased when compared with longer regimes. The REGARD-VAP trial demonstrated the non-inferiority of individualized ≤7-day therapy compared with conventional longer courses. This remained true even in cohorts rich in non-fermenting Gram-negative bacilli (NF-GNB) and carbapenem-resistant organisms while markedly reducing antibiotic-related toxicity. North American and European guidelines recommend 7–8 days as the default duration, with individualized extension for slow clinical response, bacteremia, uncontrolled foci, or profound immunosuppression. Additionally, biomarker-guided discontinuation, particularly serial procalcitonin (PCT), may reduce antibiotic days when used to enrich clinical assessment. This narrative review synthesizes guideline recommendations, trial evidence, biomarker-guided stewardship, and pathogen- and patient-specific scenarios to provide a practical framework for intensivists: treat until infection is controlled and the patient is improving, usually about 1 week, and extend therapy only with clear justification. Full article

Background/Objectives: International guidelines recommend the use of antibiotic prophylaxis for lung transplantation (LT). Although multiplex PCR (mPCR) has been shown to hasten antibiotic adaptation during pneumonia, its use to guide antibiotic prophylaxis in patients undergoing LT has not been described. We aimed to determine whether mPCR in bronchoalveolar lavage (BAL) in donor and recipient allows the early adaptation of antibiotic prophylaxis during LT. Methods: a retrospective, single-center study to evaluate the proportion of patients for whom mPCR (FilmArray Pneumonia Plus Panel^®, Biomérieux (FAPP)) in the donor and recipient BAL resulted in an early modification of antibiotic prophylaxis. We also compared the time to results using mPCR and standard microbiology and the time spent with inadequate antibiotic prophylaxis. Results: Forty-one patients were included. Donor and recipient mPCR resulted in the early adaptation of antibiotic prophylaxis in 10 (24%) patients. Standard microbiology confirmed the results of mPCR in 90% of them. FAPP resulted in an antibiotic escalation based on donor (9/10) or recipient (1/10) BAL identification, mainly Group 3 Enterobacterales and non-fermenting Gram-negative bacilli. The time to results was 1.7 (1.5–2.4) h for mPCR vs. 74.3 (41.5–92.7) h for standard microbiology (p < 0.001) on donor BAL and 1.7 (1.5–2.4) h vs. 92.8 (48.4–112.9) h (p < 0.001) on recipient BAL. Patients with mPCR-based adaptation had a 71.9 (30.7–92.1) h reduction in the duration of inadequate antibiotic prophylaxis. Conclusions: mPCR in donor and recipient BAL during LT might lead to faster adaptation and a reduction in the time spent with inadequate antibiotic prophylaxis. Full article

Urinary tract infections (UTIs) are among the most common pathologies, with a high incidence in women and hospitalized patients. Their diagnosis is based on the presence of clinical symptoms and signs in addition to the detection of microorganisms in urine trough urine cultures, a time-consuming and resource-intensive test. The goal was to optimize UTI detection through artificial intelligence (machine learning) using non-microbiological laboratory parameters, thereby reducing unnecessary cultures and expediting diagnosis. A total of 4283 urine cultures from patients with suspected UTIs were analyzed in the Microbiology Laboratory of the University Hospital Virgen de las Nieves (Granada, Spain) between 2016 and 2020. Various machine learning algorithms were applied to predict positive urine cultures and the type of isolated microorganism. Random Forest demonstrated the best performance, achieving an accuracy (percentage of correct positive and negative classifications) of 82.2% and an area under the ROC curve of 87.1%. Moreover, the Tree algorithm successfully predicted the presence of Gram-negative bacilli in urine cultures with an accuracy of 79.0%. Among the most relevant predictive variables were the presence of leukocytes and nitrites in the urine dipstick test, along with elevated white cells count, monocyte count, lymphocyte percentage in blood and creatinine levels. The integration of AI algorithms and non-microbiological parameters within the diagnostic and management pathways of UTI holds considerable promise. However, further validation with clinical data is required for integration into hospital practice. Full article

Background: Antimicrobial resistance (AMR) in Acinetobacter spp., Pseudomonas spp., and Stenotrophomonas maltophilia poses a significant risk in healthcare-associated infections. Constant monitoring using quantitative metrics is necessary to direct empirical treatment. Methods: We conducted a retrospective observational study at the Fundeni Clinical Institute, Bucharest, Romania, analysing antibiogram data from January 2021 to December 2024. Over 200,000 microbiological records were screened, and 1189 isolates of the three targeted pathogens were included. The Multiple Antibiotic Resistance Index (MARI) was applied to evaluate selective pressure across years, hospital departments, sample types, and hospitalisation categories. Results: Acinetobacter baumannii and Pseudomonas aeruginosa exhibited the highest resistance levels, with median MARI values exceeding 0.25 in 2024, particularly in Intensive Care and Transplant units. In contrast, S. maltophilia showed lower overall MARI values, though resistance variability increased in 2024 (extremes up to 0.30). Notably, resistance to carbapenems in Acinetobacter spp. rebounded in 2024, while Pseudomonas spp. demonstrated a favourable trend of decreasing resistance to several β-lactams. Conclusion: Our findings underscore significant interspecies differences in AMR dynamics and highlight the utility of MARI as a valuable operational indicator. Ongoing local surveillance is needed for refining empirical treatment protocols and informing antimicrobial stewardship in Romanian hospitals. Full article

Background/Objectives: Granulomatous lesions of the head and neck arise from diverse infectious and non-infectious causes, with tuberculosis (TB) being a predominant etiology. This retrospective study analyzed 42 cases from the archives of university of Baghdad, College of Dentistry (1975–2025). This study aimed to characterize the clinicopathological features of these lesions and to assess the diagnostic performance of histochemical stains and real-time PCR in identifying infectious etiologies—particularly Mycobacterium tuberculosis—in formalin-fixed, paraffin-embedded (FFPE) tissue samples. Methods: Definitive diagnoses included 25 TB cases confirmed through clinical, microbiological, and therapeutic follow-up at the Baghdad Tuberculosis Institute, and 17 non-TB cases classified by predefined clinicopathological criteria supported by relevant clinical data. Zieh–Neelsen (ZN), Periodic acid–Schiff (PAS), and Grocott methenamine silver (GMS) stains were employed to identify acid-fast bacilli and fungal organisms. Statistical analysis was performed using SPSS version 26, with significance set at p ≤ 0.05. Results: The mean patient age was 36.28 years (SD = 20.6), with a female predominance (59.5%). Necrotizing granulomas were identified in 69% of cases and were strongly associated with tuberculosis, which was detected in 59.5% of specimens. ZN staining showed a sensitivity of 16.7% for tuberculosis, while PCR sensitivity was highly dependent on sample age. The detection rate was 33.3% in samples archived for less than 10 years but only 10% in older samples, resulting in an overall sensitivity of 24.0% for tuberculous cases. Langhans-type giant cells were significantly more frequent in necrotizing granulomas and strongly associated with tuberculosis infection (p = 0.001). Fungal infections, predominantly aspergillosis, were confirmed by PAS and GMS in 11.9% and 9.5% of cases, respectively, and were confined to non-necrotizing granulomas. The mandible was the most commonly affected site, and soft tissue lesions were significantly associated with necrotizing granulomas (p = 0.004). Conclusions: These findings underscore the complementary role of histopathology, histochemical stains, and molecular diagnostics in improving the evaluation and diagnosis of granulomatous inflammation in head and neck lesions. Full article

Background: Artificial non-nutritive sweeteners (NNSs), such as sucralose, have been associated with gut microbiota (GM) alterations. However, the impact of rebaudioside A (reb A), a natural NNS, on GM has received limited scrutiny. Objective: The objective of this study was to examine the response of GM composition to sucralose and reb A in rats under two dietary conditions. Methods: Male Wistar rats (150–200 g) fed with a normal diet (ND) or a high-fat diet (HFD) were randomly assigned to receive sucralose (SCL), reb A (REB), glucose (GLU, control), or sucrose (SUC). The NNS interventions were administered in water at doses equivalent to the acceptable daily intake (ADI). After eight weeks, the GM composition in fecal samples was analyzed through 16S ribosomal RNA gene sequencing. Results: The NNSs did not modify the diversity, structure, phylum-level composition, or Firmicutes/Bacteroidetes (F/B) ratio of the GM in rats under ND or HFD. However, REB with HFD decreased Bacilli and increased Faecalibacterium abundance at the class level. SCL and REB in rats receiving ND reduced the genera Romboutsia and Lactobacillus. Conclusions: Our study suggests that when sucralose or reb A is consumed at recommended doses, there is no alteration in the diversity or the composition of the GM at the phylum level. The clinical relevance of these findings lies in the potential modifications of the GM at specific taxonomic levels by the consumption of these NNSs. Further research involving humans and including a broader range of microbial analyses is warranted. Full article

Background/Objectives: Non-fermenting Gram-negative bacilli (NFGNB) represent a significant clinical challenge due to their intrinsic and acquired resistance, particularly in immunocompromised patients. Infections cause by NFGNB are associated with high morbidity and mortality, especially among patients with cystic fibrosis and hematologic malignancies. This study aimed to assess the in vitro susceptibility of clinically relevant NFGNB isolates to two newer antibiotics, cefiderocol and aztreonam/avibactam, and an established antibiotic, trimethoprim/sulfamethoxazole. Methods: This retrospective, monocentric study analysed 94 NFGNB isolates (30 Pseudomonas aeruginosa, 30 Acinetobacter sp., 24 Stenotrophomonas maltophilia, and 10 Burkholderia cepacia complex). Susceptibility testing for cefiderocol, aztreonam/avibactam, and trimethoprim/sulfamethoxazole was conducted using gradient strip method. MIC values were interpreted using EUCAST breakpoints, ECOFFs, or alternative criteria when necessary. Results: All S. maltophilia isolates were susceptible to cefiderocol (FCR) and aztreonam/avibactam (A/A) based on ECOFFs, with one strain resistant to trimethoprim–sulfamethoxazole (COT). Burkholderia cepacia complex strains also showed high susceptibility to FCR, with only one isolate exceeding the ECOFF for A/A, and 20% resistant to COT. All Acinetobacter sp. isolates were susceptible to FCR; however, most MIC values clustered at or just below the ECOFF value. In P. aeruginosa, one isolate was resistant to FCR, and three isolates (10%) were resistant to A/A. Interestingly, confirmed carbapenemase producers remained susceptible to both FCR and A/A. Most A/A MIC values for P. aeruginosa were just below the ECOFF. Conclusions: Cefiderocol and aztreonam/avibactam demonstrated promising in vitro activity against clinically relevant NFGNB, including carbapenem-resistant strains. These findings support their potential role as therapeutic options for difficult-to-treat infections, particularly in immunocompromised patients. Full article

Colistin has re-emerged as a last-resort antibiotic for treating infections caused by multidrug-resistant (MDR) Gram-negative bacilli (GNB). However, increasing resistance threatens its efficacy. This study aimed to evaluate colistin resistance trends among clinical isolates of Gram-negative bacilli isolated over a five-year period at a large Emergency Hospital in North-Eastern Romania. A total of 23,143 GNB strains were isolated during the study period, including 14,531 Enterobacterales and 8294 non-fermenting Gram-negative bacilli. The percentage of colistin-resistant strains among those analyzed was 3.98%. Species-specific analysis focused on Klebsiella spp., Escherichia coli, Enterobacter spp., Citrobacter spp., Pseudomonas spp., and Acinetobacter spp. Klebsiella spp. exhibited the highest prevalence of colistin resistance, accounting for over 80% of all colistin-resistant strains, with annual resistance rates fluctuating between 12.97% and 21.64%. Colistin resistance among E. coli was low (0.18–1.25%). Citrobacter spp. showed no resistance in the last three years of the study, and Enterobacter spp. maintained relatively stable resistance (3–5%). Resistance in Pseudomonas spp. remained below 1%, while Acinetobacter spp. showed a resistance rate of 5.43%. Several distinct resistance phenotypes were identified among Klebsiella spp., Pseudomonas spp., and Acinetobacter spp. strains, reflecting both endemic and sporadic circulation patterns. The study highlights a persistent presence of colistin resistance, especially in Klebsiella spp., underlining the importance of ongoing surveillance. Despite low resistance in other species, the emergence of resistant strains underscores the need for robust antimicrobial stewardship and infection control policies. Full article

Due to the significant number of microbiologically negative periprosthetic joint infections (PJIs), understanding the trend in etiology and resistance patterns is essential for the correct management of these infections. Currently, few studies have been published in Spain. In this study, we analyzed the incidence, clinical characteristics, etiology, and antibiotic resistance in patients with PJIs over the last 5 years in Navarra. In this multicentric and retrospective study, all patients diagnosed with PJIs in Navarra from 2019 to 2023 were included. Of the total 156 PJIs, 23% had negative cultures and 56% of these patients had been treated with antibiotics prior to sampling. Staphylococcus epidermidis with methicillin resistance was the predominant etiological agent, followed by Staphylococcus aureus and Cutibacterium acnes. Forty percent of the Gram-positive cocci (GPC) and 35% of the Gram-negative bacilli (GNB) were multidrug-resistant organisms (MDROs). Quinolone resistance was 46% for staphylococci and 18% for Gram-negatives. In addition, 9% of staphylococci were resistant to rifampicin. Antibiotic therapy administration prior to sampling is one of the main problems for microbiological diagnosis and is present more frequently in culture-negative PJIs (56%). New sequencing techniques could improve this difficulty. The high percentage of resistance in the microorganisms causing PJI leads us to reconsider the empirical treatment for suspected PJI, with the use of different therapeutic approaches depending on the time of infection and the possible use of new non-antibiotic therapies. Full article

In recent years, one of the most important issues in public health is the rapid growth of antibiotic resistance among pathogens. Multidrug-resistant (MDR) strains (mainly Enterobacteriaceae and non-fermenting bacilli) cause severe infections, against which commonly used pharmaceuticals are ineffective. Therefore, there is an urgent need for new treatment options and drugs with innovative mechanisms of action. Natural compounds, especially alkaloids, are showing promising potential in this area. This review focuses on the ability of the isoquinoline alkaloid berberine (BRB) to overcome various resistance mechanisms against conventional antimicrobial agents. BRB has demonstrated significant activity in inhibiting efflux pumps of the RND (Resistance-Nodulation-Cell Division) family, such as MexAB-OprM (P. aeruginosa) and AdeABC (A. baumannii). Moreover, BRB was able to decrease quorum sensing activity in both Gram-positive and Gram-negative pathogens, resulting in reduced biofilm formation and lower bacterial virulence. Additionally, BRB has been identified as a potential inhibitor of FtsZ, a key protein responsible for bacterial cell division. Particularly noteworthy, though requiring further investigation, are reports suggesting that BRB might inhibit β-lactamase enzymes, including NDM, AmpC, and ESβL types. The pleiotropic antibacterial actions of BRB, distinct from the mechanisms of traditional antibiotics, offer hope for breaking bacterial resistance. However, more extensive studies, especially in vivo, are necessary to fully evaluate the clinical potential of BRB and determine its practical applicability in combating antibiotic-resistant infections. Full article

Background: Bloodstream infections (BSIs) caused by multidrug-resistant non-fermenting Gram-negative bacilli, particularly Pseudomonas aeruginosa and Acinetobacter baumannii, represent a growing public health concern, especially in tertiary care settings. This study aimed to describe the epidemiological and antimicrobial resistance trends of P. aeruginosa and A. baumannii isolated from blood cultures over an eight-year period (2017–2024) at a tertiary infectious disease hospital in Bucharest, Romania, especially in the context of the disruption caused by the SARS-CoV-2 pandemic. Methods: A retrospective study was conducted on 43,951 blood cultures processed at the National Institute of Infectious Diseases. Species identification and antibiotic susceptibility testing (AST) were performed using VITEK2, MALDI-TOF MS, and supplementary phenotypic methods. AST interpretation followed EUCAST guidelines. Results: Out of all of the positive blood cultures, 112 (3.63%) were P. aeruginosa and 158 (5.12%) A. baumannii. Multidrug-resistance (MDR) was identified in 46% of P. aeruginosa and 90.73% of A. baumannii isolates. Resistance trends varied, with P. aeruginosa showing a decrease in MDR rates post-COVID-19 pandemic and following antimicrobial stewardship implementation. In contrast, A. baumannii displayed persistently high resistance, with carbapenem and aminoglycoside resistance rates reaching 100% by 2024. Colistin resistance, though low overall, increased in the latter years. Conclusions: The findings highlight the dynamic nature of antimicrobial resistance among P. aeruginosa and A. baumannii. Effective infection control and antimicrobial stewardship programs are crucial in curbing the rise of MDR strains, particularly amid healthcare system disruptions such as the COVID-19 pandemic. Full article

Dormancy occurs when Mycobacterium tuberculosis (Mtb) enters a non-replicating and metabolically inactive state in response to hostile environment. During this state, it is highly resistant to conventional antibiotics, which increase the urgency to develop new potential drugs against dormant bacilli. In view of this, the dormancy survival regulator (DosR) protein is thought to be an essential component that plays a key role in bacterial adaptation to dormancy during hypoxic conditions. Herein, the NP-lib database containing natural product compounds was screened virtually against the binding site of the DosR protein using the MTiopen screen web server. A series of computational analyses were performed, including redocking, intermolecular interaction analysis, and MDS, followed by binding free energy analysis. Through screening, 1000 natural product compounds were obtained with docking energy ranging from −8.5 to −4.1 kcal/mol. The top four lead compounds were then selected for further investigation. On comparative analysis of intermolecular interaction, dynamics simulation and MM/GBSA calculation revealed that M3 docked with the DosR protein (docking score = −8.1 kcal/mol, RMSD = ~7 Å and ΔG Bind = −53.51 kcal/mol) exhibited stronger stability than reference compound Ursolic acid (docking score = −6.2 kcal/mol, RMSD = ~13.5 Å and ΔG Bind = −44.51 kcal/mol). Hence, M3 is recommended for further validation through in vitro and in vivo studies against latent tuberculosis infection. Full article

Rising global temperatures challenge poultry production by disrupting the cecal microbiota, which is essential for chicken health. Thermal manipulation (TM) during embryogenesis is a potential strategy to enhance thermotolerance in broilers. This study examined TM’s effects on the cecal microbiome, body weight (BW), and body temperature (BT) under chronic heat stress (CHS). Fertile Indian River eggs (n = 800) were incubated under control (37.8 °C, 56% RH) or TM conditions (39 °C, 65% RH for 18 h per day from embryonic day 10 to 18). On post-hatch day 18, male chicks were assigned to either CHS (35 ± 0.5 °C for five days) or thermoneutral conditions (24 ± 0.5 °C). The CHS-TM group showed a significantly higher BW than the CHS-CON group (p < 0.05). Under thermoneutral conditions, TM chicks had a lower BT on day 1 (p < 0.05), while the CHS-TM group exhibited a non-significant BT reduction compared to the CHS-CON group under heat stress (p > 0.05). An analysis of the gut microbiome showed that the beta diversity analysis (PERMANOVA, p < 0.05) indicated distinct microbial shifts. Firmicutes and Bacteroidota dominated the phylum level, with CHS increased Bacilli and Lactobacillus while reducing Lachnospirales in the CHS-TM group. These findings suggest that TM modulates gut microbiota and mitigates BW loss, offering a potential strategy to enhance broilers’ resilience to heat stress. Full article

The skin microbiome is identified as one of the crucial factors in several pathological conditions, including its potential capacity in modulating cancer progression and response to treatment. A strong association of Bacilli and Betaproteobacteria classes and the Bacteroidetes phylum with melanoma is described in patients with cutaneous malignancies, while an imbalance of S. epidermidis and S. aureus is related to the progression of other skin cancers. In the present study, we characterized the microbial community in suspected lesions of 35 patients, classified, after histological analysis, as malignant melanoma lesions and benign non-melanoma lesions. Mirrored healthy skin were also included as negative control. No significant difference in alpha and beta diversity was observed when samples were categorized in four different groups (melanoma samples vs. contralateral healthy samples; melanoma samples vs. benign lesions; benign lesions vs. contralateral controls; melanoma controls vs. benign controls). The differential abundance analyses show that Corynebacterium urealyticum is more abundant in melanoma samples compared to their control, while Roseomonas gilardii is less abundant in melanoma. Staphylococcus massiliensis, Bacillus coagulans, Paracoccus yeei, Corynebacterium jeikeium, and Corynebacterium pyruviciproducens are present only in melanoma samples when compared with benign lesions. Full article

Introduction: The increase in the rates of multidrug-resistant bacteria in healthcare environments has been recognized as a global public health problem. In view of the scarcity of data on the neonatal population, this study aimed to provide information on the genotypic and epidemiological characteristics of Gram-negative microorganisms isolated from colonization and infection sites in neonates admitted to a tertiary university center of high complexity. Methods: Enterobacterales and non-fermenting Gram-negative bacilli previously collected in a prospective cohort study were submitted to genotypic identification, detection of extended-spectrum β-lactamases (ESBL), carbapenemases and biofilm production, detection of specific virulence markers in Pseudomonas aeruginosa, and typing by pulsed-field gel electrophoresis. Results: The data found here revealed higher rates of infection by Klebsiella spp. and Serratia marcescens that caused bloodstream infection and pneumonia, respectively. In this study, high biofilm production was observed, with 95.0% of Enterobacterales and 100% of non-fermenting Gram-negative bacilli being producers. Most of the P. aeruginosa isolates carried pathogenicity factors such as alginate, hemolytic phospholipase C, exotoxin A, and rhamnolipids. The phenotypic analysis of ESBL revealed that 16 (5.3%) isolates produced these enzymes. Four of these isolates (66.7%) carried the CTX-M-9 gene, three (50%) carried the TEM gene, and one (16.7%) was positive for the SHV and CMY-2 genes. Univariate and multivariate Cox regression analyses were used to identify risk factors for colonization and infection by Gram-negative microorganisms. The results of multivariate analysis revealed that biofilm production by these microorganisms was associated with the persistence of colonization by the same pathogen in the newborn and increased by 75% the daily probability of the newborn developing infection. The production of ESBL also increased the daily probability of infection by 46.8 times. Conclusions: Enterobacterales showed average biofilm production, while the majority of non-fermenting Gram-negative bacilli were strong producers. The present data increase our knowledge of the molecular epidemiology of important Enterobacterales species, with emphasis on ESBL-producing Enterobacter cloacae and Klebsiella pneumoniae with emerging epidemiological potential in the neonatal intensive care unit of a tertiary university hospital. Furthermore, the results highlight the need for the monitoring and implementation of control measures and for restricting the use of broad-spectrum antibiotics. Full article