Search Results (83)

End-stage chronic kidney disease markedly increases susceptibility to infections due to compromised immune function and other physiological alterations. Bacteremia is responsible for higher mortality rates in hemodialysis patients compared to the general population. Our study aimed to investigate the incidence and clinical outcomes among patients with end-stage CKD and associated infections. The study retrospectively analyzed admitted patients between 1 January 2023 and 31 May 2025. Among 56 hospitalized patients with CKD and infection (30 hemodialysis [HD], 26 non-HD), baseline comorbidity profiles were broadly comparable. Microbiology was frequently positive (46/56, 82.1%), dominated by Staphylococcus aureus (25/98, 25.5%), Klebsiella pneumoniae (19.98, 19.4%), and Escherichia coli (15/98, 15.3%). Crude in-hospital mortality was higher in HD (46.7% vs. 15.4%; p = 0.012; RR 3.03). In multivariable logistic regression, HD remained independently associated with death (adjusted OR 38.22, 95% CI 1.55–940.53; p = 0.026), alongside hypotension (OR 17.55, 1.46–210.92; p = 0.024) and male sex (OR 4.41, 1.29–15.11; p = 0.018); model performance was strong (AUC 0.867). In this single-center cohort of infected patients with end-stage CKD, maintenance hemodialysis was independently associated with higher in-hospital mortality, even after adjustment for age, sex, comorbidity burden, hypotension, and length of stay; hypotension and male sex were additional risk factors. LOS and most presenting features did not differ meaningfully by dialysis status. Our findings also emphasize the urgent necessity for heightened surveillance of local antimicrobial resistance patterns and underscore the profound vulnerability of hemodialysis patients to severe infectious outcomes, which is exacerbated by immunosuppressive conditions and the limited efficacy of available therapeutic options against resistant pathogens. Full article

Background/Objectives: Infections remain a leading cause of morbidity and mortality following liver transplantation, with bloodstream infections (BSIs) representing one of the most critical complications. This study aimed to identify factors associated with mortality in liver transplant recipients who developed BSIs over a 10-year period. Methods: This retrospective study was conducted at a tertiary university hospital between 1 April 2014 and 31 December 2024. A total of 467 adult patients underwent liver transplantation during the study period. Among 467 patients, a total of 210 bloodstream infection episodes occurring in 136 patients were included in the study. Results: BSIs occurred in 29.1% (136/467) of patients, with a total of 210 episodes. The median age was 55 years (IQR: 45–63). Most transplants (95.2%) were from living donors. Hepatitis B virus infection (27.1%) was the most common underlying etiology of cirrhosis. The majority of BSIs (61.2%) occurred within the first three months post-transplant. A total of 242 pathogens were isolated, with ESBL-producing Enterobacterales identified in 72.6% and carbapenem-resistant Enterobacterales (CRE) in 30.1% of cases. Notably, carbapenem resistance among Klebsiella spp. was high at 51.78%. The overall mortality rate was 14.28%. Multivariate analysis identified that a high Pitt Bacteremia Score (hazard ratio [HR] 1.502, 95% confidence interval [CI] 1.361–1.657, p < 0.001) and CRE infection (HR 3.644, 95% CI 1.380–9.620, p = 0.009) were independent predictors of mortality. Conclusions: BSIs are a significant post-transplant complication with high antimicrobial resistance. The Pitt bacteremia score is a strong predictor of mortality and may guide early risk stratification and clinical management in liver transplant recipients. Full article

Background and Objectives: Secondary bacterial infection drives poor outcomes in older adults with COVID-19, but age-specific microbiology and its interaction with severity scores are not well defined. We characterized respiratory and pleural pathogens, resistance profiles, and their impact on day-5 SOFA/APACHE II in octogenarians versus younger adults. Methods: We performed a retrospective cohort study of adults with RT-PCR-confirmed coronavirus disease 2019 (COVID-19) at a tertiary infectious diseases center (≥80 years, n = 152; <65 years, n = 327). Respiratory and pleural samples were processed according to EUCAST standards. Identification employed matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pathogen distributions, susceptibilities, and rates of superimposed pneumonia, empyema, and bacteremia were compared by age, and associations between secondary pneumonia, day-5 SOFA/APACHE II, and 28-day mortality were analyzed. Results: Sputum was obtained in 67.1% of older and 65.7% of younger adults, with numerically higher culture positivity in older patients (73.5% vs. 65.1%). Pathogen spectra were similar, dominated by Streptococcus pneumoniae (24.0% vs. 24.3%), methicillin-susceptible Staphylococcus aureus (MSSA) (18.7% vs. 20.7%), methicillin-resistant Staphylococcus aureus (MRSA) (9.3% vs. 6.4%), and Klebsiella pneumoniae, including extended-spectrum β-lactamase (ESBL)-producing strains. Empyema was more frequent in octogenarians (7.9% vs. 3.1%), and pleural cultures were usually positive. Meropenem retained 100% activity against ESBL-producing K. pneumoniae and Pseudomonas in both strata. In ≥80-year-olds, superimposed pneumonia was associated with higher day-5 SOFA (6.6 vs. 5.5) and APACHE II (24.3 vs. 21.0) scores and markedly increased 28-day mortality (37.5% vs. 9.8%). Conclusions: In octogenarians with COVID-19, secondary bacterial pneumonia and empyema are frequent, microbiologically similar to younger adults, and strongly amplify organ dysfunction and mortality even with largely preserved carbapenem susceptibility. Full article

Blood culture remains the gold standard for identifying bloodstream infections caused by bacteria and fungi. Isolation of the culprit microorganism onto agar plates also facilitates antimicrobial susceptibility testing. The purpose of this study was to determine the contamination rates, pathogen profile, and antimicrobial resistance in a secondary healthcare setting in a two-year timeframe. In this study, data regarding blood cultures of the years 2023 and 2024 were retrospectively analyzed to address the above questions. Blood cultures were incubated for seven days before being discarded as negative. The percentage of positive blood cultures for both years was 14.3%. Most positive cultures contained Gram-positive cocci, with a prevalence of coagulase-negative Staphylococci. In descending order, 72.72% were coagulase-negative Staphylococci, 15.15% were Staphylococcus aureus, and 12.12% were Streptococci. One strain of S. aureus was methicillin-resistant (MRSA), and one strain of Enterococcus faecium was vancomycin-resistant (VRE). Of the Gram-negative rods, 78.3% were Enterobacterales. Of these, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the top pathogens. The remainder comprised eight strains of Pseudomonas aeruginosa, four strains of Acinetobacter baumannii (one pandrug-resistant), three strains of Stenotrophomonas maltophilia, one strain of Sphingomonas paucimobilis, and one strain of Campylobacter jejuni. The isolated fungi comprised Candida parapsilosis, Candida glabrata, and Candida tropicalis. Of the isolated Escherichia coli strains, 39.5% were resistant to ciprofloxacin regardless of origin (outpatient or hospitalized patients). Outpatient samples were taken in a Hemodialysis Unit that collaborates with our laboratory, obtained from patients with fever or other signs of infection. Distinguishing true bacteremia from contamination remains challenging. The contamination rate in our study was quite high at 5.3%. Since there is no dedicated phlebotomy team in our healthcare setting, in light of our results, educational courses have been conducted to demonstrate the best practices for sample collection. Full article

Background: Klebsiella species are a leading cause of Gram-negative bacteremia associated with nosocomial infections. They exhibit higher antimicrobial resistance compared to other Enterobacterales, emphasizing their role as a “sentinel organism”. While the impact of inappropriate empiric therapy has been studied, data specific to Klebsiella bacteremia are limited due to small sample sizes. This study aims to provide high-resolution data on Klebsiella bacteremia and assess the impact of appropriate empirical therapy on clinical outcomes. Methods: We conducted a retrospective study of patients with Klebsiella bacteremia hospitalized at Beilinson Hospital between 2012 and 2022. Patients were categorized into two groups based on the appropriateness of empiric therapy. The primary outcome was 30-day all-cause mortality; subgroup analyses evaluated mortality in ESBL bacteremia treated with either carbapenems or piperacillin-tazobactam, and carbapenems versus aminoglycosides. Propensity score weighting and inverse probability treatment-weighted models were used to adjust for confounding. Results: Among 1132 patients, 79% received appropriate empirical therapy. This therapy was associated with reduced 30-day mortality (OR = 0.59, 95% CI: 0.46–0.76) and a shorter hospital stay (median 7 vs. 11 days, p < 0.001). Other significant risk factors for mortality included a higher Charlson comorbidity score (OR = 1.06), assistance with ADL (OR = 2.16), prior hospitalization (OR = 1.31), and a higher SOFA score (OR = 1.32). No significant mortality differences were observed in ESBL subgroups treated with carbapenems versus piperacillin-tazobactam (p = 0.2) or carbapenems versus aminoglycosides (p = 0.9). Conclusions: Early appropriate empirical therapy significantly reduces 30-day mortality in Klebsiella bacteremia. These findings highlight the importance of timely, appropriate empirical therapy and suggest choosing less broad-spectrum therapy. However, the lack of molecular data on resistance mechanisms limits the ability to assess strain-specific outcomes and may affect generalizability. Despite this, the study offers valuable insights for optimizing empirical therapy and advancing antimicrobial stewardship in the era of rising resistance. Full article

Emerging evidence suggests some bacterial infections may be early signs of hidden cancers rather than random events. Yet this link remains under-recognized in practice, representing an often-missed diagnostic opportunity. Large registry studies show that certain infections are linked to a sharply increased short-term risk of cancer detection, with most of the excess diagnoses clustering in the first 6 months after the index episode. Key associations include the following: (i) anaerobic or gut-derived bacteremia with Bacteroides, Clostridium, Fusobacterium, or pks⁺ Escherichia coli before colorectal neoplasm; (ii) Streptococcus gallolyticus/bovis bacteremia and colorectal neoplasm; (iii) cryptogenic Klebsiella pneumoniae liver abscess and pancreaticobiliary or colorectal cancer; (iv) non-resolving pneumonia and segmental collapse before lung cancer. Overall, short-term cancer detection risks range from about 3% after unselected Gram-negative bacteremia to ~8% or higher after cryptogenic liver abscess—similar to accepted thresholds that justify targeted cancer work-up. Even hidden tumors disrupt immunity, compromise barriers, and create conditions that favor microbial invasion. This review synthesizes evidence for the “sentinel infection phenotype”; outlines pathogen-specific associations, including their possible pathogenetic mechanisms; and proposes a practical diagnostic framework. Recognizing these infection signatures may enable earlier cancer detection and better outcomes. Full article

Background: Patients with hematologic malignancies are highly vulnerable to Gram-negative bacterial bloodstream infections (GNB-BSIs) due to underlying disease-related immunosuppression, intensive chemotherapy, and repeated invasive interventions, rendering these infections a significant cause of morbidity and mortality in this population. This study aimed to evaluate the epidemiological, clinical, and microbiological features of GNB-BSIs in hospitalized patients with hematologic malignancies, and to compare clinical and microbiological factors between survivors and non-survivors. Methods: We conducted a retrospective cohort study in a tertiary university hospital hematology ward in Türkiye, including adult patients diagnosed with BSIs due to Gram-negative bacteria between January 2005 and December 2024. Demographic characteristics, microbiological profiles, antimicrobial resistance rates, and clinical outcomes were analyzed. We compared survivors and non-survivors to determine differences in clinical and microbiological characteristics. Results: A total of 321 patients with hematologic malignancies experienced 441 episodes of GNB-BSIs. The median age was 46 years, and 59% of them were male. The most frequently isolated pathogen was Escherichia coli (53.3%), followed by Klebsiella spp. (20.6%) and Pseudomonas spp. (7.5%). Extended-spectrum β-lactamase-producing/third-generation cephalosporin-resistant (ESBL/3GCR) and carbapenem-resistant isolates were observed in 21.1% and 13.3% of isolates, respectively. The overall mortality rate was 26.5%. ICU admission, multidrug resistance, and persistent bacteremia were observed more often among non-survivors. Additionally, prolonged fever duration (median 8 vs. 3 days, p < 0.0001), elevated CRP (p = 0.001), and higher procalcitonin levels (p = 0.046) were detected in non-survivors. Conclusions: In patients with hematologic malignancies, E. coli and Klebsiella spp. remain the predominant pathogens causing bloodstream infections, while persistent bacteremia, ESBL/3GCR, and carbapenem resistance are associated with higher mortality. Notably, carbapenem resistance showed a temporal increase over the study period, underscoring the need for continuous surveillance and timely adaptation of empirical treatment strategies. Full article

Background: Carbapenem-resistant Enterobacterales (CRE) are designated by the World Health Organization as critical-priority pathogens. While global outcomes are well documented, regional data from the Middle East remain limited. Methods: We performed a retrospective cohort study of adults with confirmed CRE infections admitted to King Fahad Hospital of the University, Saudi Arabia, between 2019 and 2024. Clinical, microbiological, and therapeutic data were analyzed. Primary outcomes were infection recurrence, recurrence-related readmissions, and all-cause mortality at 14, 30, and 90 days. Predictors were assessed using univariate tests and multivariate Cox regression. Results: Among 101 patients (mean age 65 years, 57% female), Klebsiella pneumoniae predominated (94%), with OXA-48 detected in 70%. Most infections were hospital-acquired (78%). Recurrence occurred in 16.8% of cases, with 12.9% requiring readmission. Mortality reached 22.8% at 14 days, 30.7% at 30 days, and 42.6% at 90 days. Diabetes mellitus predicted recurrence (p = 0.024). Independent predictors of 90-day mortality were pneumonia (HR 2.39, 95% CI 1.23–4.64), critical care admission (HR 6.24, 95% CI 2.44–15.97), and hypotension (HR 4.10, 95% CI 1.84–9.15). Elevated Pitt bacteremia and INCREMENT-CPE scores also stratified risk. Conclusions: CRE infections in Saudi Arabia impose a heavy clinical burden, with high recurrence, frequent readmissions, and late mortality. Identifying drivers of recurrence and mortality highlights opportunities for targeted risk stratification. Beyond treatment choices, these findings emphasize the need for proactive surveillance, integrated stewardship, and early recognition of high-risk patients. Region-specific evidence such as this is critical to shaping infection control policies and guiding future multicenter research into novel therapeutic approaches. Full article

Multidrug-resistant (MDR) bloodstream infections (BSIs) constitute a major challenge in intensive care units, with the COVID-19 pandemic compromising infection control and potentially increasing MDR incidence. Comparative data between COVID and non-COVID ICU populations remain limited. The MARTINI study is a retrospective observational analysis held in a tertiary hospital during the COVID-19 pandemic (2020–2022) encompassing adult patients with MDR BSIs admitted to COVID and non-COVID ICUs. Demographics, comorbidities, severity scores, microbiology, resistance patterns, and outcomes were accessed and compared. A binary logistic regression model and multivariate regression was performed to identify independent predictors of ICU mortality. Among the study’s 156 patients (106 COVID-ICU, 50 non-COVID-ICU), COVID-ICU patients were significantly older with higher comorbidity and severity scores. Gram-negative pathogens predominated in both cohorts, mainly Acinetobacter baumannii and Klebsiella pneumoniae, with comparable resistance mechanisms. Timing of bacteremia onset and initiation of appropriate therapy did not differ between groups. However, ICU mortality was markedly higher in COVID-ICU patients (74.5% vs. 38%, p < 0.001). Age, SOFA score, the presence of systemic inflammation (SIRS) and COVID-19 infection were identified as independent predictors of mortality. Although pathogen distribution and resistance were similar across groups, COVID-ICU patients experienced significantly poorer outcomes. Strengthened infection control and timely and targeted antimicrobial therapy are essential to diminish MDR bacteremia risk in critically ill populations. Full article

Background/Introduction: Carbapenem-resistant Klebsiella pneumoniae (CRKP) bacteremia is a serious public health problem due to its high mortality rate and limited treatment options. This study aimed to identify risk factors associated with ceftazidime–avibactam (CAZ-AVI) resistance in CRKP bacteremia and to evaluate its impact on clinical outcomes. Methods: This retrospective single-center cohort study included adult patients with CRKP bloodstream infections treated at a tertiary hospital in Türkiye between January 2021 and December 2024. Demographic, clinical, and laboratory data were collected, and risk factors for CAZ-AVI resistance and 30-day mortality were analyzed. Results: Among 154 patients, 42.8% had CAZ-AVI-resistant strains. Resistant infections were associated with longer hospital stays and higher Charlson Comorbidity Index (CCI) scores. The resistance rate was lower in patients with intra-abdominal infections, while fluoroquinolone and fosfomycin use was more common in the resistant group. The overall 30-day mortality rate was 57%. Pitt bacteremia score and creatinine levels were identified as independent predictors of mortality. Discussion: CAZ-AVI resistance in CRKP bacteremia appears to develop in patients with prolonged hospitalization and high comorbidity burden. These factors likely increase exposure to resistant microorganisms and antibiotic pressure, complicating treatment outcomes. Conclusions: CAZ-AVI resistance in CRKP bacteremia is associated with specific clinical risk profiles and contributes to high mortality. Identifying high-risk patients and optimizing antimicrobial stewardship are essential to improve prognosis. Full article

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant therapeutic challenge, particularly when multiple resistance mechanisms, such as metallo-β-lactamases (MBLs) and Klebsiella pneumoniae carbapenemase (KPC), coexist. Case description: We describe a case of a 51-year-old male with a post-sternotomy surgical site infection and concurrent bacteremia caused by a CRKP. Sternal swab and mediastinal liquid culture results highlighted CRKP harboring bla_NDM and bla_KPC genes, while the blood isolate showed bla_CTX and bla_KPC, indicating phenotypic resistance to ceftazidime-avibactam. All the strains exhibited phenotypic susceptibility to meropenem-vaborbactam (MEV), despite having a high minimum inhibitory concentration. Following clinical failure of MEV-based therapy, combination treatment with aztreonam (ATM) and imipenem/cilastatin/relebactam (IMI/REL), plus gentamicin, was initiated. Therapy was well tolerated and resulted in microbiological eradication and full clinical recovery. The patient completed 49 days of ATM and IMI/REL without relapse over a 3-month follow-up period. This is, to the best of our knowledge, the first reported case of IMI/REL being used in combination with ATM. Full article

Introduction: Antimicrobial resistance has become a global concern, and few new antimicrobials are currently being developed. Fluopsin C has proven broad-spectrum activity, being a promising candidate for new antimicrobial development. To optimize antimicrobial activity, this research aimed at fluopsin C (Flp) encapsulation in liposomes to achieve controlled release and reduce cytotoxicity. Methods: Liposomal formulations were prepared by extruding formulations based on soy phosphatidylcholine (SPC) or poly (ethylene glycol)-distearoylphosphatidylethanolamine (DSPE-PEG) plus cholesterol, and were characterized by their size, polydispersity index, zeta potential, encapsulation efficiency, shelf-life stability, in vitro release profile, cytotoxicity, and antimicrobial activity against Klebsiella pneumoniae in vitro and in vivo. Results: The results indicated that the DSPE-PEG DMSO+Flp formulation presented superior physicochemical stability and unaltered antimicrobial activity. In vitro, CC₅₀ decreased by 54%. No lethal dose was obtained in mice within the concentration range tested. The most effective doses in vivo were 2 × 2 mg/kg for free fluopsin C and 1 × 2 mg/kg for DSPE-PEG DMSO+Flp, resulting in a 40% reduction in mortality from bacteremia. Only discrete inflammatory infiltration was detected in the liver, while kidney necrosis ranged from discrete to moderate. Encapsulation of fluopsin C in liposomes showed promising features supporting to use against infections by MDR K. pneumoniae. Full article

Background: The gut microbiome affects human health, and patients with cancer are no exception. In those patients, intensive chemotherapy impairs gut barrier integrity, causing dysbiosis, bacterial translocation, and higher infection risk. Objectives: This prospective study, conducted at Children’s Cancer Hospital in Egypt, profiles the microbiome of 29 pediatric patients with AML, and examines how induction chemotherapy and antibiotics affect their microbiome. Methods: Gut microbiome changes were evaluated before treatment (T1), then 7 (T2) and 21–28 days (T3) from induction start. Microbial DNA, extracted from rectal swabs or stool samples, was subjected to 16S rRNA amplicon sequencing, followed by bioinformatics and statistical analyses. Results: Treatment significantly decreased the richness and Shannon diversity of the gut microbiome and caused dysbiosis that was only partially restored at T3. Whereas Firmicutes remained the most abundant phylum throughout, Actinobacteria significantly decreased in abundance after treatment. Proteobacteria had their lowest abundance at T3, while Verrucomicrobacteria were relatively abundant at T1 but undetectable by T3. The abundance of Enterococcus and Klebsiella was associated with stool culture results, and the Proteobacteria-to-Firmicutes ratio was associated with treatment. Conclusions: Gut microbial diversity declined in patients during induction chemotherapy, with a strong association of microbial composition with stool culture results but not with bacteremia. Full article

Among the leading causes of bacteremia are Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. E. coli and K. pneumoniae are increasingly exhibiting resistance to last-resort antibiotics, such as carbapenems. Rapid and accurate identification of these pathogens is critical for timely treatment and infection control. This paper aimed to develop a computer-aided bacterial morphometric technique for identifying and classifying wild-type E. coli, K. pneumoniae, and S. aureus in a field guide fashion. A 3D laser scanning confocal microscope was used to gather key parameters of each organism: length (L, µm), circular diameter (CD, µm), volume (V, µm³), surface area-to-cross-sectional area ratio (SA/CSA, unitless), surface uniformity ratio (Str), and surface texture ratio (Sdr). Microscope images and measurement results showed that S. aureus was spherical with the shortest length (1.08 µm) and smallest volume (0.52 µm³). E. coli and K. pneumoniae were rod-shaped with lengths >2.0 µm and volumes >1.0 µm³. Carbapenem-resistant (CR) strains exhibited larger volumes than their wild-type counterparts. Surface parameters further differentiated strains: wild-type E. coli had a greater surface texture or a less smooth surface (larger Sdr) than K. pneumoniae (lower Sdr) did. CR E. coli had more surface uniformity (lower Str) than CR K. pneumoniae did. A dichotomous key based on shape, circular diameter, volume, length, and surface characteristics was developed to classify the species using a series of paired, contrasting features. This morphometric analysis can aid researchers in quickly identifying bacteria, leading to faster diagnosis of life-threatening diseases and improved treatment decisions. Full article

Infections with multidrug-resistant (MDR) organisms remain a significant cause of morbidity and mortality among liver transplant recipients, despite advances in surgical techniques and immunosuppressive therapy. This prospective observational study aimed to evaluate the impact of targeted perioperative antibiotic prophylaxis against MDR Gram-negative bacteria on postoperative infections and mortality in liver transplant recipients. Seventy-nine adult patients who underwent liver transplantation and were admitted to the ICU for more than 24 h postoperatively were included. Demographics, disease severity scores, comorbidities, and lengths of ICU and hospital stay were recorded. Colonization with carbapenem-resistant Gram-negative bacteria was assessed via preoperative and postoperative cultures from the blood, urine, rectum, and tracheal secretions. Patients were divided into two groups: those with MDR colonization or infection who received targeted prophylaxis and controls who received standard prophylaxis. Infectious complications (30.4%) occurred significantly less frequently than non-infectious ones (62.0%, p = 0.005). The most common infections were bacteremia (22.7%), pneumonia (17.7%), and surgical site infections (2.5%), with most events occurring within 15 days post-transplant. MDR pathogens isolated included Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. Although overall complication and mortality rates at 30 days and 3 months did not differ significantly between groups, the targeted prophylaxis group had fewer infectious complications (22.8% vs. 68.5%, p = 0.008), particularly bacteremia (p = 0.007). Infection-related mortality was also significantly reduced in this group (p = 0.039). These findings suggest that identification of MDR colonization and administration of targeted perioperative antibiotics may reduce septic complications in liver transplant patients. Further prospective studies are warranted to confirm benefits on outcomes and resource utilization. Full article