Clinical presentation and outcome of hemodialysis tunneled catheter-related bloodstream infection in older persons.

BACKGROUND: The use of a tunneled catheter as the primary vascular access among old hemodialysis patients is frequent. Catheter-related bloodstream infection (CRBSI) is a common complication, associated with increased mortality. Data regarding the clinical presentation and outcomes of CRBSI among old hemodialysis patients is limited. METHODS: All chronic hemodialysis patients hospitalized between 2010 and 2022 with CRBSI were included. Patients were classified into two groups: old adults (≥ 75) and younger patients. Clinical, microbiological, and outcome data were collected and analyzed. RESULTS: One hundred and fifty-four patients with CRBSI were identified. Fifty-seven were aged ≥ 75 years. Mean age in the older and younger groups was 81.2 ± 5 and 59.7 ± 12.7, respectively. Male gender was predominant (64%). Charlson comorbidity score and Pitt bacteremia score were comparable among both groups. Norton score < 14 was more common among old persons (n = 24, 67% versus n = 21, 31%, p < 0.001), as well as nursing-home residence. Gram-negative pathogens and Staphylococcus aureus were common in both groups. The frequency of inappropriate empirical antimicrobial treatment was higher among older persons. Overall, in-hospital and 90-day mortality was high (age ≥ 75, 36.8%, age < 75, 24.7%, p = 0.14). Age was not significantly associated with mortality after adjustment for low Norton score, residence, and inappropriate antimicrobial therapy as well as resistance patterns of bloodstream isolates [OR = 1.2 (95% CI 0.4-3.3), p = 0.76]. CONCLUSIONS: Clinical characteristics and outcomes of CRBSI were comparable among old and young hemodialysis patients. However, the high mortality rate in this cohort suggests that the use of tunneled catheters as a permanent vascular access should be discouraged in both patient groups.

Rate and Risk Factors for Carbapenem Resistant Acinetobacter baumannii Clinical Infections in Colonized Patients.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) is an important cause of nosocomial infections. Active surveillance for CRAB carriage to identify and isolate colonized patients is used to reduce transmission. OBJECTIVES: To assess the rate and risks of clinical infection among CRAB-carrier and non-carrier patients. METHODS: Hospitalized patients from whom CRAB screening-cultures were obtained between January and June 2018 were identified retrospectively. All CRAB-carriers were compared to a convenient sample of non-carriers and were followed to detect development of CRAB clinical infection during admission. RESULTS: We compared 115 CRAB carriers to 166 non-carriers. The median age in the study group was 76 years (IQR 71-87) vs. 65 years (55-79) in the non-carriers group (P < 0.001). Residence in a nursing facility, debilitated state, and admission to medical wards vs. intensive care units were more frequent among CRAB-carriers (P < 0.001). Mechanically ventilated patients included 51 CRAB carriers (44%) and 102 non-carriers (61%). Clinical infection developed in 49 patients (17%), primarily CRAB pneumonia. Of the CRAB-carriers and non-carriers, 26/115 (23%) and 23/166 (14%), respectively, developed a clinical infection (P = 0.05). One-third of the ventilated patients were infected. Debilitated state and antibiotic treatment during hospitalization were linked to higher infection rates (P = 0.01). Adjusted analysis showed that mechanical ventilation and CRAB colonization were strongly associated with clinical infection (P < 0.05). CONCLUSIONS: The rate of CRAB infection among carriers was high. Mechanical ventilation and CRAB colonization were associated with CRAB clinical infection, primarily pneumonia.

The cationic porphyrin TMPyP4 destabilizes the tetraplex form of the fragile X syndrome expanded sequence d(CGG)n.

Fragile X syndrome, the most common cause of inherited mental retardation, is instigated by dynamic expansion of a d(CGG) trinucleotide repeat in the 5'-untranslated region of the first exon of the FMR1 gene, resulting in its silencing. The expanded d(CGG)(n) tract readily folds into hairpin and tetraplex structures which may contribute to the blocking of FMR1 transcription. In this work, we report that the cationic porphyrin 5,10,15,20-tetra(N-methyl-4-pyridyl)porphin (TMPyP4) effectively destabilizes in vitro the G'2 bimolecular tetraplex structure of d(CGG)(n) while it stabilizes the G'2 tetraplex form of the telomeric sequence d(TTAGGG)(2). Similarly to TMPyP4, the hnRNP-related protein CBF-A also destabilizes G'2 tetrahelical d(CGG)(n) while binding and stabilizing tetraplex telomeric DNA. We report that relative to each agent individually, successive incubation of G'2 d(CGG)(n) with TMPyP4 followed by exposure to CBF-A results in a nearly additive extent of disruption of this tetraplex form of the repeat sequence. Our observations open up the prospect of unfolding secondary structures of the expanded FMR1 d(CGG)(n) tract of fragile X cells by their exposure to low molecular size drugs or to proteins such as TMPyP4 or CBF-A.