Identification of streptomycin-resistant Erwinia amylovora in Iowa.

Erwinia amylovora is a bacterial pathogen that causes fire blight, an important disease in apples and pears. Applying the antibiotic streptomycin during the phenological bloom stage is considered the most effective management tactic for fire blight. Though streptomycin-resistant (SmR) E. amylovora populations have emerged in major U.S. apple-producing regions, antibiotic resistance data for medium to small-sized apple-producing regions like the Midwest is still lacking. This short communication collected symptomatic fire blight samples from Iowa apple orchards during 2022 and 2023, where recent fire blight outbreaks persisted despite streptomycin use. Among E. amylovora isolates from seven counties in central and eastern Iowa, around 90% of them were SmR. All SmR isolates exhibited a single base pair mutation in codon 43 of the rpsL gene, conferring resistance to streptomycin levels exceeding 1,000 µg/mL. Through clustered regularly interspaced short palindromic repeat (CRISPR) analysis, we characterized two E. amylovora genotypes unique to our region. Whole genome sequencing of one representative SmR isolate, IA01, confirmed its CRISPR genotype and subsequent phylogenetic analysis suggested that IA01 is genetically similar to Michigan isolates and distinct from those in eastern and western regions of North America. Furthermore, the disease-causing ability of IA01 was comparable to that of the highly virulent Ea110 strain, a streptomycin sensitive strain isolated from Michigan, in immature pears. Overall, this study underscores the urgent need for regional strategies to address antibiotic resistance and provide insights into its genetic basis and geographic distribution which are crucial for sustainable orchard management.

Sex-Specific Troponin and Creatine Kinase Thresholds After Coronary Bypass Surgery.

BACKGROUND: The impact of sex-differences on the release of cardiac biomarkers after coronary artery bypass grafting (CABG) remains unknown. The aim of our study was to (1) investigate the impact of sex-differences in cardiac biomarker release after CABG and (2) determine sex-specific thresholds for high-sensitivity cardiac troponin (hs-cTn) and creatine kinase-myocardial band (CK-MB) associated with 30-day major adverse cardiovascular events (MACE) and mortality. METHODS: A consecutive cohort of 3687 patients, comprising 643 women (17.4%) and 3044 men (82.6%), undergoing CABG from 2008 to 2021 in 2 tertiary university centers with serial postoperative cTn and CK-MB measurement was analyzed. The composite primary outcome was MACE at 30 days. Secondary end points were 30-day mortality and 5-year mortality and MACE. Sex-specific thresholds for cTn and CK-MB were determined. RESULTS: Lower levels of cTn were found in women after CABG (69.18 vs 77.57 times the upper reference limit [URL]; P < .001). The optimal threshold value for cTn was calculated at 94.36 times the URL for female patients and 206.07 times the URL for male patients to predict 30-day MACE. Female patients missed by a general threshold had increased risk for MACE or death within 30 days (cTn: MACE: odds ratio [OR], 3.78; 95% CI, 1.03-13.08; P = .035; death: OR, 4.98; 95% CI, 1.20-20.61; P = .027; CK-MB: MACE: OR, 10.04; 95% CI, 2.07-48.75; P < .001; death: OR 13.59; 95% CI, 2.66-69.47; P = .002). CONCLUSIONS: We provide evidence for sex-specific differences in the outcome and biomarker release after CABG. Sex-specific cutoffs are necessary for the diagnosis of perioperative myocardial injury to improve outcomes of women after CABG.

Cardiac shockwave therapy in addition to coronary bypass surgery improves myocardial function in ischaemic heart failure: the CAST-HF trial.

BACKGROUND AND AIMS: In chronic ischaemic heart failure, revascularisation strategies control symptoms but are less effective in improving left ventricular ejection fraction (LVEF). The aim of this trial is to investigate the safety of cardiac shockwave therapy (SWT) as a novel treatment option and its efficacy in increasing cardiac function by inducing angiogenesis and regeneration in hibernating myocardium. METHODS: In this single-blind, parallel-group, sham-controlled trial (cardiac shockwave therapy for ischemic heart failure, CAST-HF; NCT03859466) patients with LVEF ≤40% requiring surgical revascularisation were enrolled. Patients were randomly assigned to undergo direct cardiac SWT or sham treatment in addition to coronary bypass surgery. The primary efficacy endpoint was the improvement in LVEF measured by cardiac magnetic resonance imaging from baseline to 360 days. RESULTS: Overall, 63 patients were randomized, out of which 30 patients of the SWT group and 28 patients of the Sham group attained 1-year follow-up of the primary endpoint. Greater improvement in LVEF was observed in the SWT group (Δ from baseline to 360 days: SWT 11.3%, SD 8.8; Sham 6.3%, SD 7.4, P = .0146). Secondary endpoints included the 6-minute walking test, where patients randomized in the SWT group showed a greater Δ from baseline to 360 days (127.5 m, SD 110.6) than patients in the Sham group (43.6 m, SD 172.1) (P = .028) and Minnesota Living with Heart Failure Questionnaire score on day 360, which was 11.0 points (SD 19.1) for the SWT group and 17.3 points (SD 15.1) for the Sham group (P = .15). Two patients in the treatment group died for non-device-related reasons. CONCLUSIONS: In conclusion, the CAST-HF trial indicates that direct cardiac SWT, in addition to coronary bypass surgery improves LVEF and physical capacity in patients with ischaemic heart failure.