Inter-laboratory variability of caspofungin MICs for Nakaseomyces glabrata isolates - an Irish tertiary hospital experience.

Background: Nakaseomyces glabrata, formerly Candida glabrata, is an opportunistic yeast and emerging cause of human infections. The use of broth microdilution (BMD) methodologies for caspofungin (CSP) antifungal susceptibility testing (AFST) against N. glabrata is reported to be prone to high inter-laboratory variation. We aimed to compare CSP MICs of N. glabrata isolates from our institution with those obtained by the Reference Laboratory for the same isolates. Methods: All clinically significant N. glabrata isolates from 2019 to 2021 inclusive were reviewed. AFST was performed locally using the VITEK2 system with the AST-YS08 card, while E-tests were performed at the Mycology Reference Laboratory (MRL), and agreement between these two methods was evaluated - categorical and essential. Results: Forty-one isolates were reviewed during the study period - 30 from blood cultures, seven from intra-operative theatre specimens and four from sterile site drain fluids. Despite an essential agreement of 100 % within ±2 log2 dilutions, marked discrepancies were noted in interpretative breakpoints between assays with 17 Minor and 16 Major category errors. Categorical agreement was 19.5 %, with the VITEK2 over-estimating resistance. A Mann-Whitney U-test assessed the relationship of MICs across the AFST modalities, and a statistically significant difference was noted, P<0.01, with a higher mean rank for VITKEK2 outputs. Conclusion: While the VITEK2 system is highly applicable, its performance for CSP AFST is unreliable and potentially results in the mis-classification of susceptible isolates as highlighted in our study. The use of VITEK2 AST-YS08 micafungin as a sentinel echinocandin should be explored and/or the evaluation of CSP-specific E-tests as utilized by the MRL. These methods appear more consistent and less prone to the variation seen with BMD for CSP.

Antimicrobial susceptibility patterns of anaerobic bacteria at an Irish University Hospital over a ten-year period (2010-2020).

OBJECTIVES: In recent years various clinical studies have demonstrated poor outcomes in infections caused by anaerobic bacteria due to inappropriate therapy, directly due to emergence of resistant strains. This is a concern given that many anaerobic infections are treated empirically with metronidazole or a beta-lactam/beta-lactamase inhibitor combinations (e.g., co-amoxiclav, piperacillin-tazobactam). To date there is a paucity of available data on antimicrobial resistance trends of anaerobic bacteria in Ireland, and our study aims to determine such patterns among isolates processed at our institution over the last ten years. METHODS: Significant anaerobic bacteria isolated from clinical specimens processed at our laboratory from January 2010 to January 2020 inclusive were reviewed. Bacteria were identified using MALDI-TOF, with E-tests used for antimicrobial susceptibility testing. Data was processed through WHONET. RESULTS: A total of 2098 clinically significant anaerobic bacterial isolates from blood cultures (31%), theatre/intraoperative specimens (30%), aspirates and drain fluid (22%) and wound swabs (17%) were reviewed during the study period; with the majority of isolates being Bacteroides spp (32.79%, n = 688) and Clostridium spp (18.68%, n = 392). With isolates demonstrating well-recognised or inherent resistances excluded, overall resistance to tested antimicrobials was 6.40% to penicillin, 1.71% to metronidazole, 1.43% to co-amoxiclav, 13.63% to clindamycin, 0.43% to piperacillin-tazobactam and 0% to meropenem. CONCLUSION: Metronidazole and beta-lactam/beta-lactamase inhibitor combinations remain highly efficacious against the majority of anaerobic isolates reviewed, and can safely be used as empiric therapy in suspected anaerobic infections. However, periodic surveillance of resistance trends remains important.

European survey of management of patients with multidrug-resistant organisms in rehabilitation facilities.

BACKGROUND: Rehabilitation facilities have among the highest prevalence of multidrug-resistant organism (MDRO) colonization of any inpatient population. There is no formal consensus on how patients with MDROs should be managed in the rehabilitation setting. AIM: The aim of this study was to assess how rehabilitation hospitals throughout Europe manage patients with MDROs, and the impact of MDRO carriage on outcomes. DESIGN: Cross-sectional study. SETTING: Online questionnaire distributed to European rehabilitation facilities. POPULATION: European rehabilitation facilities. METHODS: A Survey Monkey® questionnaire was designed and circulated to rehabilitation hospitals via the European Union of Medical Specialists, Physical and Rehabilitation Medicine Section. RESULTS: Fifty-four responses were received of which 45 were suitable for analysis. Six out of 26 (23%) countries included in the study reported at least one rehabilitation facility with an estimated MDRO prevalence rate of 31% or higher. Screening of all patients on admission was always carried out in 33% (15 of 45) of facilities. Twenty-five of the 45 facilities (69%), aim to isolate, or cohort patients who have MDROs. Patients with MDROs wait longer for admission (36%, 16 of 45) and in the case of five hospitals admission is refused. Fifty-one percent (23 of 45) of facilities reported that colonization with an MDRO severely or moderately limits rehabilitation outcome. CONCLUSIONS: Our research shows that many of the challenges posed by MDROs are common to facilities throughout Europe. We strongly recommend that all patients are screened for MDROs on admission. We stress that any negative impact of a patients MDRO status on their rehabilitation outcome must be minimized. CLINICAL REHABILITATION IMPACT: Specific guidance on the management of rehabilitation patients with MDROs, would allow them to partake in a full rehabilitation program, while limiting the spread of MDROs.

Cytokine responses to Staphylococcus aureus bloodstream infection differ between patient cohorts that have different clinical courses of infection.

BACKGROUND: The clinical course of Staphylococcus aureus bloodstream infection is unpredictable and bacterial virulence, host immune response and patient characteristics are among the factors that contribute to the clinical course of infection. To investigate the relationship between cytokine response and clinical outcome, circulating cytokine levels were investigated in response to S. aureus bloodstream infection in patients with different clinical courses of infection. METHODS: A prospective study was carried out in 61 patients with S. aureus bloodstream infection and circulating levels of IL-6, GRO-γ, RANTES and leptin were assessed over the course of the infection. Levels were compared in patients with complicated courses of infection (e.g. infective endocarditis) versus uncomplicated courses of S. aureus bloodstream infection and methicillin-resistant S. aureus Vs methicillin-susceptible S. aureus infection. RESULTS: Significantly lower leptin levels (p < 0.05) and significantly higher IL-6 levels (p < 0.05) were detected at laboratory diagnosis in patients with complicated compared to uncomplicated S. aureus bloodstream infection. Significantly higher levels of GRO-γ were associated with MRSA infection compared to MSSA infection. CONCLUSIONS: IL-6 may be an early inflammatory marker of complicated S. aureus bloodstream infection. Leptin may be protective against the development of a complicated S. aureus bloodstream infection.

DNA microarray genotyping and virulence and antimicrobial resistance gene profiling of methicillin-resistant Staphylococcus aureus bloodstream isolates from renal patients.

Thirty-six methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates from renal patients were genetically characterized by DNA microarray analysis and spa typing. The isolates were highly clonal, belonging mainly to ST22-MRSA-IV. The immune evasion and enterotoxin gene clusters were found in 29/36 (80%) and 33/36 (92%) isolates, respectively.