Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting

CITATION: Reddy, K. & Whitelaw, A. 2021. Can the Xpert MRSA/SA BC assay be used as an antimicrobial stewardship tool? A prospective assay validation and descriptive impact assessment study in a South African setting. BMC Infectious Diseases, 21:177, doi:10.1186/s12879-021-05857-7.The original publication is available at https://bmcinfectdis.biomedcentral.comBackground: Positive blood cultures showing Gram positive cocci in clusters signifies either Staphylococcus aureus or the less-virulent coagulase-negative staphylococci. Rapid identification and methicillin susceptibility determination with the Xpert MRSA/SA BC assay can improve management of S. aureus bloodstream infection and reduce inappropriate antibiotic use. Methods: We prospectively evaluated the Xpert MRSA/SA BC assay in comparison with culture, on samples referred to our laboratory in the Western Cape, South Africa. We interviewed attending clinicians upon culture result availability, to assess antibiotic choices and estimate potential impact of the assay. Results: Of the 231 samples included, there was 100% concordance between the Xpert MRSA/SA BC assay and culture (methicillin-resistant S. aureus 15/15, methicillin-susceptible S. aureus 42/42, coagulase-negative staphylococci 170/170). Time to final result could be reduced by approximately 30 h with the assay. Of the 178 patients with adequate antibiotic history, optimisation of antistaphylococcal therapy could have occurred more than 1 day sooner in 68.9% with S. aureus bloodstream infection (31/45, 95% CI 53.2–81.4%). Six of the 11 patients with methicillin-resistant S. aureus bloodstream infection (54.5%) could have received anti-MRSA cover sooner. Fifty-four days of antibiotic therapy could have been spared, equating to 0.3 days (95% CI, 0.2–0.4) saved per patient, driven by broad-spectrum beta-lactams (32 days, in 18.0% of the cohort). Conclusion: This assay has potential as an antimicrobial stewardship tool; costing and impact on clinical outcome in patients with S. aureus bloodstream infection should be assessed.https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-021-05857-7Publisher's versio

A retrospective analysis of pathogen profile, antimicrobial resistance and mortality in neonatal hospital-acquired bloodstream infections from 2009-2018 at Tygerberg Hospital, South Africa.

BackgroundAnalysis of hospital-acquired bloodstream infection (HA-BSI) trends is important to monitor emerging antimicrobial resistance (AMR) threats and guide empiric antibiotic choices.MethodsA retrospective 10-year review of neonatal HA-BSI was performed at Tygerberg Hospital's neonatal unit in Cape Town, South Africa. Neonatal clinical and laboratory data from 2014 to 2018 (Period 2) was compared with published data from 2009 to 2013 (Period 1).ResultsThe neonatal unit's HA-BSI rate declined between periods from 3.9/1000 inpatient-days in Period 1 to 3.3/1000 inpatient-days in Period 2 (p = 0.002). Pathogen yield and blood culture contamination rate were unchanged (11.0% to 10.4%, p = 0.233; 5.1% to 5.3%, p = 0.636 respectively). Gram-negative pathogens predominated (1047/1636; 64.0%); Klebsiella species, Staphylococcus aureus, Serratia marcescens, Enterococcus species and Acinetobacter baumannii were the most frequent pathogens. Extended spectrum beta-lactamase production was observed in 319/432 (73.8%) of Klebsiella species, methicillin resistance in 171/246 (69.5%) of Staphylococcus aureus and extensive drug resistance in 115/137 (83.9%) of Acinetobacter species (2009-2018). The crude mortality rate of neonatal HA-BSI episodes increased from Period 1 to Period 2 from 139/717 (19.4%) to 179/718 (24.9%) (p = 0.014), but HA-BSI attributable mortality remained unchanged (97/139 [69.8%] vs 118/179 [65.9%], p = 0.542). The in-vitro activity of piperacillin-tazobactam and amikacin declined during Period 2 (74.6% to 61.4%; pConclusionAlthough HA-BSI rates declined in the neonatal unit, antimicrobial resistance rates in BSI pathogens remained high. Continuous BSI surveillance is a valuable tool to detect changes in pathogen and AMR profiles and inform empiric antibiotic recommendations for neonatal units in resource-limited settings

Antimicrobial resistance and antimicrobial stewardship in South Africa: a survey of healthcare workers in academic and nonacademic hospitals

Abstract Objective: Antimicrobial stewardship programmes (ASPs) facilitate appropriate antimicrobial use and require contextualization for optimal functioning. We aimed to investigate perceptions of and antimicrobial resistance (AMR) and ASPs among healthcare workers in academic and nonacademic hospitals. Design: Cross-sectional survey. Setting: Three academic (Charlotte Maxeke Johannesburg Academic, Inkosi Albert Luthuli, Tygerberg) and three nonacademic hospitals (Leratong, Prince Mshiyeni Memorial, and Paarl) in South Africa from January to June 2022. Participants: Doctors, nurses, and pharmacists. Methods: Voluntary questionnaire using Google Forms, encompassing AMR, ASPs, and selected discipline-specific components. Results: Participants comprised 79 doctors (50 academic), 178 nurses (169 academic), and 21 pharmacists (18 academic) and were female predominant. AMR was a problem in academic hospitals (74.7% vs 51.2%, p 0.004); 73.5% overall reported inappropriate antimicrobial use as a major contributor. Adequate education on antimicrobials occurred in only 36.4% overall. Microbiological testing guided therapy more often in nonacademic settings (80.0% vs 50.2%, p <0.001). In both settings, antimicrobial availability drove selection in 48.2%. Overall, ASPs improved patient care (89.8%) and reduced antimicrobial use (86.9%), although felt to override prescriber autonomy in academic settings (29.4% vs 7.5%, p 0.007), mainly among nurses. Only 50.2% reported successful local ASPs. A minority of pharmacists (20.0%) reported sufficient hospital support for ASPs. Education, involvement of infection control staff, and inclusion of nurses in ASPs were most impactful on AMR. Conclusion: Selected healthcare worker perspectives differ by category and setting and can be targeted to improve ASPs. Further studies should target a higher number of clinical staff in both settings

Decreasing fluconazole susceptibility of clinical South African Cryptococcus neoformans isolates over a decade.

BackgroundFluconazole is used in combination with amphotericin B for induction treatment of cryptococcal meningitis and as monotherapy for consolidation and maintenance treatment. More than 90% of isolates from first episodes of cryptococcal disease had a fluconazole minimum inhibitory concentration (MIC) ≤4 μg/ml in a Gauteng population-based surveillance study of Cryptococcus neoformans in 2007-2008. We assessed whether fluconazole resistance had emerged in clinical cryptococcal isolates over a decade.Methodology and principal findingsWe prospectively collected C. neoformans isolates from 1 January through 31 March 2017 from persons with a first episode of culture-confirmed cryptococcal disease at 37 South African hospitals. Isolates were phenotypically confirmed to C. neoformans species-complex level. We determined fluconazole MICs (range: 0.125 μg/ml to 64 μg/ml) of 229 C. neoformans isolates using custom-made broth microdilution panels prepared, inoculated and read according to Clinical and Laboratory Standards Institute M27-A3 and M60 recommendations. These MIC values were compared to MICs of 249 isolates from earlier surveillance (2007-2008). Clinical data were collected from patients during both surveillance periods. There were more males (61% vs 39%) and more participants on combination induction antifungal treatment (92% vs 32%) in 2017 compared to 2007-2008. The fluconazole MIC50, MIC90 and geometric mean MIC was 4 μg/ml, 8 μg/ml and 4.11 μg/ml in 2017 (n = 229) compared to 1 μg/ml, 2 μg/ml and 2.08 μg/ml in 2007-2008 (n = 249) respectively. Voriconazole, itraconazole and posaconazole Etests were performed on 16 of 229 (7%) C. neoformans isolates with a fluconazole MIC value of ≥16 μg/ml; only one had MIC values of >32 μg/ml for these three antifungal agents.Conclusions and significanceFluconazole MIC50 and MIC90 values were two-fold higher in 2017 compared to 2007-2008. Although there are no breakpoints, higher fluconazole doses may be required to maintain efficacy of standard treatment regimens for cryptococcal meningitis