Comparative assessment of Sensititre YeastOne and Micronaut-AM EUCAST for antifungal susceptibility testing in candidaemia isolates.

PURPOSE: Antifungal susceptibility testing (AFST) is essential to ensure appropriate antifungal therapy in candidaemia. This study compared two commercial colorimetric broth microdilution tests: Sensititre YeastOne (SYO; Thermo Scientific) and Micronaut-AM EUCAST AFST (M-AM; Bruker) for the AFST of Candida spp. MATERIAL AND METHODS: A total of 74 yeast strains, including C. albicans (n = 40) and non-albicans Candida species (NACS) (n = 34), were obtained from blood cultures of patients admitted to a tertiary care hospital in Belgium from 2017 to 2022. AFST by SYO and by M-AM were performed according to the manufacturers' protocols and interpreted using CLSI and EUCAST guidelines, respectively. Essential and categorical agreements (EA and CA), very major, major and minor discrepancies were calculated for amphotericin B, echinocandins and azoles considering SYO as the reference method. RESULTS: In total, 441 and 392 isolate-antifungal results were evaluable for EA and CA, respectively. SYO and M-AM, showed a high level of concordance for C. albicans strains, with an EA and CA ≥90 % for all tested antifungals. However, we noted significant discordances for NACS, the lowest EA were observed with micafungin (50 %) and voriconazole (58.8 %). These discrepancies were likely due to differences in the raw MIC values obtained by the two methods and the different interpretation breakpoints used by CLSI and EUCAST. CONCLUSION: Our study showed excellent agreement between SYO and M-AM for AFST of C. albicans, while the equivalency was lower for NACS. AFST method should be carefully selected, considering the results might impact the choice of antifungals for non-albicans candidaemia.

A systematic review of epidemiology, risk factors, diagnosis, antifungal resistance, and management of invasive aspergillosis in Africa.

Invasive aspergillosis (IA) affects more than 300,000 people annually worldwide with a case fatality rate reaching 80%. However, in Africa despite the presence of risk factors for the development of IA, the burden of these fungal infections remained unknown. This systematic review aimed to update the available information on the epidemiology and the therapeutic management of IA in Africa. The published papers were systematically searched on major medical databases from September 20 to October 10, 2021. The list of references of eligible articles and the Google scholar database were also checked in order to search for possible eligible articles. Results were reported following the Preferred Reporting Items for Systematic and Meta-analyses (PRISMA) guidelines. The search yielded 1864 articles of which 29 met the inclusion criteria. This systematic review showed the existence of IA in Africa. The prevalence of IA can reach 27% with a fatality rate of more than 60%. The most common clinical form of IA found was invasive pulmonary aspergillosis. The main predisposing conditions identified were neutropenia, HIV/AIDS, renal transplant recipients, and renal failure. Aspergillus section Flavi and Nigri were the main Aspergillus species identified and Aspergillus section Fumigati was uncommon. The main management strategy for IA cases was to start antifungal therapy only after a failure of broad-spectrum antibiotic therapy. This review provided evidence of the existence of invasive aspergillosis in Africa and especially a high rate of undiagnosed invasive aspergillosis cases.

Performance evaluation of direct fluorescent antibody, Focus Diagnostics Simplexa™ Flu A/B & RSV and multi-parameter customized respiratory Taqman® array card in immunocompromised patients.

BACKGROUND: Molecular assays for diagnosis of Flu A, Flu B, and RSV with short turn-around-time (TAT) are of considerable clinical importance. In addition, rapid and accurate diagnosis of a large panel of viral and atypical pathogens can be crucial in immunocompromised patients. OBJECTIVES: First, to evaluate the performance of the Simplexa™ Direct assay system in comparison with direct fluorescent antibody (DFA) and customized Taqman® Array Card (TAC) testing for RSV, Flu A, and Flu B in immunocompromised patients. Second, to evaluate different algorithms for the detection of respiratory pathogens in terms of cost, turn-around-time (TAT) and diagnostic yield. STUDY DESIGN: We collected 125 nasopharyngeal swabs (NTS) and 25 BAL samples from symptomatic immunocompromised patients. Samples for which Simplexa™ and TAC results were discordant underwent verification testing. The TAC assay is based on singleplex RT-PCR, targeting 24 viruses, 8 bacteria and 2 fungi simultaneously. RESULTS: The overall sensitivity was significantly lower for DFA testing than for the two molecular methods (p<0.05). Performance characteristics of Simplexa™ testing were not significantly different compared to TAC testing (p>0.1). For BAL samples only, the sensitivity and specificity of the Simplexa™ assay was 100%. In total, 6.7, 16 and 18% of samples were positive for Flu A, Flu B or RSV by DFA, Simplexa™ and TAC testing, respectively. When considering not only these pathogens but also all results for TAC, the method identified 93 samples with one or more respiratory pathogens (62%). A co-infection rate of 15.3% was found by TAC. The estimated costs and TAT were 8.2€ and 2h for DFA, 31.8€ and 1.5h for Simplexa™ and 55€ and 3h for TAC testing. CONCLUSIONS: Performing the Simplexa™ test 24h a day/7 days a week instead of DFA would considerably improve the overall sensitivity and time-to-result, albeit at a higher cost generated in the laboratory. Performing the TAC would increase the diagnostic yield and detection of co-infections significantly.

Rapid molecular detection of methicillin-resistant Staphylococcus aureus: a cost-effective tool for infection control in critical care?

Control strategies for methicillin-resistant Staphylococcus aureus (MRSA) in critical care remain debated. Timely detection of MRSA carriers is crucial to an effective isolation policy. In this issue, Harbarth and colleagues report rapid MRSA screening among intensive care unit-admitted patients using a PCR assay. Preemptive isolation for all admissions until screened negative for MRSA was associated with a reduction of intensive care unit-acquired MRSA infections in one of two study units. The data provide preliminary evidence to the effectiveness of a MRSA control strategy combining rapid screening by a molecular method and preventive isolation. Further controlled studies are needed to evaluate the cost-effectiveness of this intervention.