A Novel IncX Plasmid Mediates High-Level Oxytetracycline and Streptomycin Resistance in Erwinia amylovora from Commercial Pear Orchards in California.

Isolates of the fire blight pathogen Erwinia amylovora with high-level resistance to oxytetracycline (minimal inhibitory concentration [MIC] > 100 µg/ml) and to streptomycin (MIC > 100 µg/ml) were recovered from four commercial pear orchards in California between 2018 and 2020. The two representative oxytetracycline- and streptomycin-resistant (OxyTcR-SmR) strains 32-10 and 33-1 were as virulent as the antibiotic susceptible strain 13-1 in causing blossom blight of pear and were recovered more than 50% of the time 7 days after co-inoculation to pear flowers with strain 13-1. In the field, inoculation of strain 32-10 to pear flowers that were pretreated with oxytetracycline at 200 µg/ml did not reduce disease compared with an untreated control. Four OxyTcR-SmR strains were subjected to draft genome sequencing to identify the genetic determinants of antibiotic resistance and their location. A 43.6-kb IncX plasmid, designated pX11-7, was detected in each of the four strains, and this plasmid encoded the tetracycline-resistance gene tetB and the streptomycin-resistance gene pair strAB within a large putatively mobile genetic element consisting of the transposon Tn10 that had inserted within the streptomycin-resistance transposon Tn6082. We also determined that pX11-7 was conjugative and was transferred at a rate that was 104 to 105 higher into an E. amylovora strain isolated in California compared with an E. amylovora strain that was isolated in Michigan. The occurrence of high levels of resistance to both oxytetracycline and streptomycin in E. amylovora strains from commercial pear orchards in California significantly limits the options for blossom blight management in these locations.

Crotalus atrox venom-induced cellular toxicity: Early wound progression involves reactive oxygen species.

Understanding the mechanisms that produce cellular cytotoxicity is fundamental in the field of toxicology. Cytotoxic stimuli can include organic toxins such as hemorrhagic snake venom, which can lead to secondary complications such as the development of necrotic tissue and profuse scarring. These clinical manifestations mimic cytotoxic responses induce by other organic compounds such as organic acids. We used hemorrhagic snake venom and human embryonic kidney cells (HEK 293T) as a model system to better understand the cellular responses involved in venom induced cytotoxicity. Cells stimulated with Crotalus atrox (CA) (western diamondback) venom for 4 or 10 h demonstrated significant cytotoxicity. Results from 2',7'-Dichlorodihydrofluorescein diacetate (H2 DCF-DA) assays determine CA venom stimulation induces a robust production of reactive oxygen species (ROS) over a 3-h time course. In contrast, pretreatment with polyethylene glycol (PEG)-catalase or N-acetyl cysteine (NAC) prior to CA venom stimulation significantly blunted H2 DCFDA fluorescence fold changes and showed greater cytoprotective effects than cells stimulated with CA venom alone. Pre- incubating HEK293T cells with the NADPH oxidase (NOX) pan-inhibitor VAS2870 prior venom stimulation significantly minimized the venom-induced oxidative burst at early timepoints (≤2 h). Collectively, our experiments show that pre-application of antioxidants reduces CA venom induce cellular toxicity. This result highlights the importance of ROS in the early stages of cytotoxicity and suggests muting ROS production in noxious injuries may increase positive clinical outcomes.

Clinical characteristics of RA patients with secondary SS and association with joint damage.

OBJECTIVES: Secondary SS (sSS) is a common extra-articular manifestation of RA. There are conflicting data regarding the association of sSS with worse joint damage. This study aims to characterize sSS patients in an RA cohort and study the association between sSS and joint damage. METHODS: We conducted a cross-sectional study of RA patients with ≥1 year of follow-up at a large academic centre. Subjects with co-morbid diseases that can also result in sicca symptoms were excluded from the analysis. Subjects were considered to have sSS if they were reported as having sSS by their rheumatologist at recruitment into the cohort and had the diagnosis confirmed by chart review. The primary outcome was Sharp score using bilateral hand radiographs at recruitment. We constructed a linear regression model to determine the association of sSS status and Sharp score adjusted by age, gender, disease duration and ACPA and RF status. RESULTS: We studied 829 RA subjects, mean age 57 years, 83% female, mean RA duration 13 years, 74% seropositive; 85 subjects (10.3%) had sSS. We observed a female predominance (95.3%), longer mean disease duration (16.9 years) and higher frequency of RF or ACPA positive among patients with sSS and RA. Having sSS at baseline was associated with higher Sharp scores (P = 0.03), independent of age, gender, RA disease duration and seropositive disease. CONCLUSION: In our RA cohort, RA subjects with sSS had worse joint damage, suggesting that sSS is a marker of more aggressive disease.

Factors influencing emergency department preference for access to healthcare.

INTRODUCTION: African-Americans are more likely than Caucasians to access healthcare through the emergency department (ED); however, the reasons behind this pattern are unclear. The objective is to investigate the effect of race, insurance, socioeconomic status, and perceived health on the preference for ED use. METHODS: This is a prospective study at a tertiary care ED from June to July 2009. Patients were surveyed to capture demographics, healthcare utilization, and baseline health status. The primary outcome of interest was patient-reported routine place of healthcare. Other outcomes included frequency of ED visits in the previous 6 months, barriers to primary care and patient perception of health using select questions from the Medical Outcomes Study Short Form 36 (SF-36). RESULTS: Two hundred and ninety-two patients completed the survey of whom 58% were African-American and 44% were uninsured. African-Americans were equally likely to report 3 or more visits to the ED, but more likely to state a preference for the ED for their usual place of care (24% vs. 13%, p < 0.01). No significant differences between groups were found for barriers to primary care, including insurance. African-Americans less often reported comorbidities or hospitalization within the previous 6 months (23% vs. 34%, p = 0.04). On logistic regression modeling, African-Americans were more than 2 times as likely to select the ED as their usual place of healthcare (OR 2.24, 95% CI 1.22 - 4.08). CONCLUSION: African-Americans, independent of health insurance, are more likely than Caucasians to designate the ED as their routine place of healthcare.

Multiple preoperative endoscopic interventions are associated with worse outcomes after laparoscopic Heller myotomy for achalasia.

BACKGROUND: The effect of preoperative pneumatic dilation or botulinum toxin injection on outcomes after laparoscopic Heller myotomy (LHM) for achalasia is unclear. We compared outcomes in patients with and without multiple preoperative endoscopic interventions. METHODS: This cohort study categorized achalasia patients undergoing first-time LHM by the number of preoperative endoscopic interventions: zero or one intervention vs. two or more interventions. Outcomes of interest included surgical failure (defined as the need for re-intervention), gastrointestinal symptoms, and health-related quality of life. Logistic regression modeling was performed to determine the independent effect of multiple preoperative endoscopic interventions on the likelihood of surgical failure. RESULTS: One hundred thirty-four patients were included; 88 (66%) had zero to one preoperative intervention, and 46 (34%) had multiple (more than one) interventions. The incidence of surgical failure was 7% in the zero to one intervention group and 28% in the more than one intervention group (p < 0.01). Greater improvements in gastrointestinal symptoms and health-related quality of life were seen in the zero to one intervention group. On logistic regression modeling, the likelihood of surgical failure was significantly higher in the more than one intervention group (odds ratio = 5.1, 95% confidence interval 1.6-15.8, p = 0.005). CONCLUSIONS: Multiple endoscopic treatments are associated with poorer outcomes and should be limited to achalasia patients who fail surgical therapy.