[Effectiveness of comprehensive echinococcosis control measures with emphasis on management of infectious source in Sichuan Province from 2010 to 2022]

OBJECTIVE

To evaluate the effectiveness of comprehensive echinococcosis control measures with emphasis on management of infectious source in Sichuan Province from 2010 to 2022, so as to provide insights into formulation of future control interventions.

METHODS

Data pertaining to comprehensive echinococcosis control measures with emphasis on management of infectious source and echinococcosis surveillance in Sichuan Province from 2010 to 2022 were collected. The effectiveness of comprehensive echinococcosis control measures with emphasis on management of infectious source was evaluated with prevalence of human echinococcosis, detection of newly diagnosed echinococcosis patients, prevalence of Echinococcus infection in domestic dogs, prevalence of cystic echinococcosis in livestock, prevalence of alveolar echinococcosis in small mammals and awareness of echinococcosis control knowledge, and Spearman's rank correlation analysis.

RESULTS

The prevalence of human echinococcosis reduced from 1.08% in 2010 to 0.40% in 2022 in Sichuan Province (χ2 = 1 482.97, P < 0.05), with a reduction from 0.30% to 0.02% in the detection of newly diagnosed echinococcosis cases (χ2 = 2 776.41, P < 0.05), a reduction from 15.87% to 0.46% in the prevalence of Echinococcus infection in domestic dogs (χ2 = 20 823.96, P < 0.05), a reduction from 8.05% to 1.07% in the prevalence of cystic echinococcosis in livestock (χ2 = 1 296.02, P < 0.05), and the awareness of echinococcosis control knowledge increased from 50.65% to 95.24% (χ2 = 34 938.63, P < 0.05); in addition, there was a year-specific prevalence rate of alveolar echinococcosis in small mammals (χ2 = 164.07, P < 0.05). Spearman's rank correlation analysis revealed that the detection of newly diagnosed echinococcosis cases correlated positively with the prevalence of Echinococcus infections in domestic dogs (rs = 0.823, P < 0.05) and the prevalence of cystic echinococcosis in livestock (rs = 0.795, P < 0.05), and correlated negatively with the awareness of echinococcosis control knowledge (rs = - 0.918, P < 0.05), and the prevalence of Echinococcus infection in domestic dogs correlated positively with the prevalence of cystic echinococcosis in livestock (rs = 0.753, P < 0.05) and negatively with the awareness of echinococcosis control knowledge (rs = -0.747, P < 0.05); however, there was no correlation between the prevalence of Echinococcus infections in domestic dogs and the prevalence of alveolar echinococcosis in small mammals (rs = -0.750, P > 0.05).

CONCLUSIONS

The comprehensive echinococcosis control measures with emphasis on management of infectious source had achieved remarkable effectiveness in Sichuan Province; however, the transmission chain of echinococcosis has not been interrupted. Reinforced comprehensive echinococcosis control measures with emphasis on management of infectious source and sustained tracking evaluation of the effectiveness are recommended in Sichuan Province.

Development of terpenoid repellents against Aedes albopictus: a combined study of biological activity evaluation and computational modelling

To explore novel terpenoid repellents, 22 candidate terpenoid derivatives were synthesized and tested for their electroantennogram (EAG) responses and repellent activities against Aedes albopictus. The results from the EAG experiments revealed that 5-(2-hydroxypropan-2-yl)-2-methylcyclohex-2-en-1-yl formate (compound 1) induced distinct EAG responses in female Aedes albopictus. At concentrations of 0.1, 1, 10, 100, and 1000 mg/L, the EAG response values for compound 1 were 179.59, 183.99, 190.38, 193.80, and 196.66 mV, demonstrating comparable or superior effectiveness to DEET. Repellent activity analysis indicated significant repellent activity for compound 1, closest to the positive control DEET. The in silico assessment of the ADMET profile of compound 1 indicates that it successfully passed the ADMET evaluation. Molecular docking studies exhibited favourable binding of compound 1 to the active site of the odorant binding protein (OBP) of Aedes albopictus, involving hydrophobic forces and hydrogen bond interactions with residues in the OBP pocket. The QSAR model highlighted the influential role of hydrogen-bonding receptors, positively charged surface area of weighted atoms, polarity parameters of molecules, and maximum nuclear-nuclear repulsion force of carbon-carbon bonds on the relative EAG response values of the tested compounds. This study holds substantial significance for the advancement of new terpenoid repellents.

Comparison of Doxycycline or Minocycline to Sulfamethoxazole-Trimethoprim for Treatment of Stenotrophomonas maltophilia Pneumonia

BACKGROUND

Stenotrophomonas maltophilia is a multidrug-resistant organism with limited antibiotic treatment options. Minocycline and doxycycline may be appropriate, but clinical data are limited.

OBJECTIVE

To compare tetracyclines (minocycline and doxycycline [TCN]) with standard of care, sulfamethoxazole-trimethoprim (TMP-SMZ), in S. maltophilia pneumonia treatment.

METHODS

This retrospective, 2-center study evaluated patients treated for S. maltophilia pneumonia with TCN or TMP-SMZ for clinical success, defined as resolution of leukocytosis, fever, and tachypnea. Patients were classified as treatment with TCN or TMP-SMZ based on definitive agent used for ≥50% of the treatment course and ≥4 days. Inclusion criteria were age ≥18 years, S. maltophilia confirmed on respiratory culture from January 2013 to November 2020, and appropriate definitive antibiotic dosing. Pregnancy, incarceration, S. maltophilia-resistant or intermediate to definitive therapy, and combination therapy for treatment of S. maltophilia pneumonia were exclusion criteria. Secondary outcomes were microbiologic success and recurrence or reinfection within 30 days requiring treatment.

RESULTS

A total of 80 patients were included (21 TCN [15 minocycline, 6 doxycycline], 59 TMP-SMZ). There was no difference in clinical success (28.6% vs 25.4%; P = 0.994), microbiologic success (n = 28, 55.6% vs 66.4%; P = 0.677), or recurrence or reinfection (n = 24, 66.7% vs 26.7%; P = 0.092) between TCN and TMP-SMZ, respectively.

CONCLUSION AND RELEVANCE

Clinical and microbiologic success rates were similar in patients treated with TCN compared with TMP-SMZ for S. maltophilia pneumonia. These data suggest minocycline and doxycycline may be options to treat S. maltophilia pneumonia, but conclusive clinical data continue to be lacking.

The Role of Radiotherapy in Patients with Refractory Hodgkin Lymphoma after Brentuximab Vedotin and -/or Immune Checkpoint Inhibitors

PURPOSE/OBJECTIVE(S)

Brentuximab vedotin (BV) and immune checkpoint inhibitors (ICIs) had important roles in the treatment of relapse or refractory (R/R) Hodgkin lymphoma (HL). Treatment of refractory disease after BV and -/or ICIs remains a challenge. This study was conducted to evaluate the efficacy and safety of radiotherapy for R/R HL after failure to BV or ICIs.

MATERIALS/METHODS

We retrospectively analyzed patients in two institutions with R/R HL who had failed after first-line therapy, and were refractory to BV or ICIs, and received radiotherapy (RT) thereafter. The overall response rate (ORR), duration of response (DOR), progression-free survival (PFS) and overall survival (OS) were analyzed.

RESULTS

A total of 19 patients were enrolled. First-line systemic therapy consisted of ABVD (84.2%), AVD + ICIs (10.5%) and BEACOPP (5.3%), respectively. After first-line therapy, 15 patients (78.9%) were refractory, and 4 patients (21.1%) relapsed. After diagnosis of R/R HL, 8 patients (42.1%) received BV, and 17 patients (89.5%) received ICIs. RT was delivered in all 19 patients who failed after BV or ICIs. In 16 efficacy-evaluable patients, the ORR and CR rate were 100% and 100%. The median DOR was 17.2 months (range, 7.9 to 46.7 months). 3 patients progressed at outside of the radiation field. The in-field-response rate was 100%. The 12-month PFS and OS were 84.4% and 100%, respectively. No patients were reported with sever adverse events.

CONCLUSION

This study concluded that radiotherapy was effective and safe for refractory HL after BV or ICIs. Further prospective studies were warranted.

[Prevalence of Echinococcus infection in small mammals captured from Shiqu County, Sichuan Province from 2015 to 2020]

OBJECTIVE

To investigate the prevalence of Echinococcus infection in small mammals in Shiqu County, Sichuan Province from 2015 to 2020, so as to provide insights into echinococcosis control in Shiqu County.

METHODS

One setting with frequent activity of small mammals was sampled as the survey site from each of 9 townships where human alveolar echinococcosis was hyperendemic, in Shiqu County, Sichuan Province from 2015 to 2020. Two quadrats measuring 50 m × 50 m were assigned in each survey site during the period between July and August from 2015 to 2020 to capture all small mammals in quadrats, and the species of small mammals were identified by morphological characteristics. All captured small mammals were dissected in the field and Echinococcus infection was identified by visual examinations. The affected organs of Echinococcus - infected small mammals were collected, and Echinococcus infection was detected using PCR assay, with Echinococcus species characterized. The prevalence of Echinococcus infection was calculated in small mammals, and the trends in the prevalence of Echinococcus infection were analyzed during the period from 2015 to 2020. In addition, the prevalence of Echinococcus infection was compared in small mammals using visual examinations and PCR assay.

RESULTS

A total of 2 692 small mammals were captured in the survey sites of Shiqu County from 2015 to 2020, and morphology characterized 1 360 Microtus fuscus (50.52%) and 1 332 Plateau pika (49.48%). The prevalence rates of Echinococcus infection were 35.63%, 19.16%, 21.41%, 8.40%, 7.68% and 4.44% by visual examinations and 18.96%, 5.36%, 5.61%, 4.58%, 3.30% and 0.37% by PCR assay in small mammals in Shiqu County from 2015 to 2020, both showing a tendency towards a decline year by year (χ² = 215.024 and 117.045, both P values < 0.001). The prevalence of Echinococcus infection was significantly higher in small mammals by visual examinations than by PCR assay during the period from 2015 to 2020 except in 2018 (χ²= 33.597, 21.815, 51.373, 17.268 and 9.537, all P values < 0.01). PCR assay detected a reduction in the prevalence of E. multilocularis infection from 10.21% to 0.37% and a reduction in the prevalence of E. shiquicus infection from 8.75% to 0 in small mammals in Shiqu County from 2015 to 2020, both appearing a tendency towards a decline year by year (χ² = 117.045 and 43.436, both P values < 0.001). In addition, the prevalence of E. multilocularis and E. shiquicus infections reduced from 15.19% to 0.45% and from 8.23% to 0 in M. fuscus, and the prevalence of E. multilocularis and E. shiquicus infections reduced from 7.76% to 0 and from 9.01% to 0 in P. pika in Shiqu County from 2015 to 2020.

CONCLUSIONS

M. fuscus and P. pika were dominant species of small mammals in Shiqu County, Sichuan Province from 2015 to 2020, and E. multilocularis infection was mainly found in M. fuscus and E. shiquicus infection mainly found in P. pika. The prevalence of Echinococcus infection appeared a tendency towards a decline in both M. fuscus and P. pika year by year during the period from 2015 to 2020.

958. Is Dalbavancin a Reliable Treatment Option in Socially Challenged Populations?

Background

Dalbavancin (DAL) is a lipoglycopeptide antibacterial that was granted full FDA approval for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in 2014. Due to its long terminal half-life of 14.4 days, DAL has been used off-label to treat infections that require a prolonged duration of treatment, especially in patients with challenging social situations. We aimed to evaluate the differences in outcomes and clinical effectiveness of DAL, primarily in deep-seated infections in an academic health system.

Methods

We performed a retrospective review of all the adult patients ( &gt;18 years old) with DAL orders within our health care system between January 1st, 2016, and July 16th, 2021. Baseline characteristics were collected, including age, gender, race, history of illicit drug use disorder (IDUD), diagnosis, and recommended DAL regimen. Follow-up data, including completion of treatment, outpatient visits to infectious diseases clinic, and recurrence of infection within six months, were also collected.

Results

A total of 50 patients were identified during the study time frame. The median age was 45.5 years, 62% were male, 82% were white, and 62% had a history of IDUD (Table 1). DAL was used predominantly to treat bone and joint infections (e.g., osteomyelitis, septic arthritis), followed by bacteremia, endocarditis, and ABSSSI (Table 1). The most common regimen used is 1500 mg weekly for two doses. Patients with a history of IDUD are less likely to complete the recommended treatment regimen (64.5% vs. 100%; p=0.003), and less likely to follow in the infectious disease clinic (16.1% vs. 52.6%, p=0.016) when compared to patients with no history of IDUD. Twelve patients had either objective evidence or clinical suspicion for recurrence within six months. Although there was a trend for higher recurrence among patients with IDUD (29% vs. 16%), there was no statistical difference with a p-value of 0.332 (Table 2). In addition, DAL was well-tolerated among most patients. Table 1.Baseline characteristics of the study population.

Table 2. Outcomes of patients with dalbavancin orders.

Conclusion

Although DAL is a safe and convenient antimicrobial option, more efforts should be made to establish consistent treatment regimens for its off-label use. Those with social barriers such as IDUD might benefit from additional measures to ensure treatment completion and proper follow-up.

Disclosures

All Authors: No reported disclosures.

Experimental evaluation and structure-activity relationship analysis of bridged-ring terpenoid derivatives as novel Blattella germanica repellent

Cockroaches are urban pests that are very difficult to control. Using repellents is a green, safe and effective strategy for their control. In order to find novel cockroach repellents, the repellent activity of 45 bridged-ring terpenoid derivatives synthesized from β-pinene against Blattella germanica was tested. The relationship between the molecular structure of these bridged-ring terpenoid derivatives and their repellent activity against Blattella germanica was also analysed. The results show that some of the bridged-ring terpenoid derivatives exhibit good repellent activity against Blattella germanica, and six compounds (RR = 60.44-87.32%) show higher repellent activity against Blattella germanica than DEET (RR = 54.77%), making them promising for development as new cockroach repellents. Quantitative structure-activity relationship (QSAR) analysis revealed that the HOMO-1 energy, Kier and Hall index (order 2), Balaban index, and relative positive charged surface area of bridged-ring terpenoid derivatives have effects on repellent activity against Blattella germanica. The present study may provide a theoretical basis for the high-value use of β-pinene and can be helpful to the development of novel repellents against Blattella germanica.

Analysis results of 579 cases of genomic copy number variation sequencing of pregnant women in prenatal diagnosis

OBJECTIVE

This study explored the usefulness of genomic copy number variation sequencing (CNV-Seq) in the prenatal diagnosis of pregnant women.

PATIENTS AND METHODS

Based on prenatal diagnostic indications, CNV-Seq analysis was done in the samples from the 579 pregnant women of the 7 subgroups that included advanced maternal age (group A), high risk noninvasive prenatal test (NIPT) (group B), high risk Down's (Group C), abnormal ultrasound findings (Group D), adverse pregnancy history (Group E), chromosome abnormalities in couples (Group F), and the mixed group (Group G).

RESULTS

A total of 57 (9.84%) cases have abnormal CNV-Seq results. Among them, 21 cases were aneuploid chromosomal number abnormalities (3.63%, 21/579), and 36 cases were CNV abnormalities (6.22%, 36/579), including 7 cases of pathogenic copy number alteration (pCNA) (1.21%, 7/579) and 29 cases variants of uncertain significance (VUS) (5.01%, 29/579). The total detection rates of abnormal CNV-Seq in Group G and Group B were 20.27% (15/74) and 15.91% (14/88), which were significantly higher than those in other groups (p < 0.05). Among 36 cases of abnormal CNV-Seq, 7 cases were chromosome fragment deletion or duplication, which were pathogenic CNV, and some rare chromosomal diseases were detected.

CONCLUSIONS

Patients with a high risk of NIPT or multiple indications of prenatal diagnosis are highly suspected of chromosomal diseases. CNV-Seq is a useful tool for detecting chromosome abnormalities for prenatal diagnosis of pregnant women more accurately and provides more comprehensive information for prenatal diagnosis to reduce birth defects.

The Incidence of Ocular Complications in Candidemic Patients and Implications for the Practice of Routine Eye Exams

Background

Ocular candidiasis is a known complication of candidemia. Given the poor ocular penetration of echinocandins, there is some concern that the increasing use of echinocandins may portend an increased incidence of ophthalmic complications. We examined the changing trends in antifungal prescribing patterns and the incidence of ophthalmic complications after candidemia.

Methods

Patients with blood cultures positive for Candida species between January 2014 and June 2020 who underwent screening fundoscopic examination by an ophthalmologist were analyzed. The χ² analysis was used to compare antifungal prescriptions and ocular exam findings before and after 2016. Trend analysis was also performed to assess temporal changes in prescribing practices and eye exam findings.

Results

There were 226 candidemia cases during the study period, 129 (57.1%) of which underwent screening eye exams. From 2014 to 2015, 24 of 37 (64.5%) patients received eye-penetrating antifungals compared to 36 of 92 (39.1%) from 2016 to 2020 (P = .008). Overall, 30 of 129 (23.3%) patients had abnormal eye exams with the prevalence of abnormal findings being 7 of 37 (18.9%) before 2016 compared to 23 of 92 (25%, P = .46) thereafter. A trend analysis revealed an increase in abnormal eye findings over the study period (P = .008). Of the 30 patients who had abnormal eye exams, 9 (30%) had a change in systemic antifungal therapy from echinocandins to eye-penetrating antifungals. Echinocandin use was associated with abnormal eye findings.

Conclusions

Prescription of eye-penetrating antifungals for candidemia has trended down since 2016. This was associated with a concomitant increase in abnormal findings on screening fundoscopy. Abnormal eye exams were not uncommon throughout our study period.

309. TB Quantiferon Testing Predicts Mortality in Patients with COVID-19

Background

Finding reliable clinical predictors for severity of COVID-19 has been challenging. Interferon gamma (IFNG) plays an important role in viral replication. QuantiFERON-TB (QFT) test relies on IFNG release in response to antigens. A positive or negative test signifies adequate IFNG response, whereas an indeterminate result is obtained when such a response is lacking. In this study, we have attempted to see if an indeterminate QFT result can provide prognostic information on patients with COVID–19.

Survival Probability in patients with Covid - 19 and an indeterminate TB Quantiferon test result

Methods

This is a retrospective study of patients who were admitted at our institute with COVID–19 and had a QFT done within one month of the positive SARS-CoV-2 nucleic acid amplification test result. Patient charts were analyzed for clinical course and outcomes, including in-hospital mortality (primary outcome), 90-day mortality, respiratory failure, requirement for intubation and other complications that would portend a more severe disease course.

Results

A total of 120 patient charts were analyzed, out of which 43 (35.8%) had an indeterminate QFT. All the indeterminate results were due to an inadequate mitogen response. The indeterminate QFT group had a 41.86% (18/43) in-hospital mortality vs. 9.09% (7/77) in the negative or positive QFT group (p-value of < 0.001). The 90-day mortality was similar between the two groups. Patients with indeterminate QFT also had a higher incidence of respiratory failure (97.7% vs. 75.3%; p-value = 0.020), requirement for mechanical ventilation (55.8% vs. 23.4%; p-value < 0.001), requirement of ECMO (25.58% vs. 0%; p-vale < 0.001), requirement of pressor (48.83% vs. 14.28%; p-value < 0.001) and requirement for renal replacement therapy (32.5% vs. 1.3%; p-value < 0.001), when compared to patients with a negative or positive QFT. Patients in indeterminate group had a higher hospital length of stay than the other group (p-value = 0.035).

Conclusion

Our study indicates that patients with COVID-19 who fail to mount an adequate IFNG mitogen response in QFT assay have worse clinical outcomes and a more complicated and protracted clinical course. Evaluating cell-mediated immune responses through commercially available IFNG release assays may yield a promising strategy to predict COVID-19 clinical outcomes.

Disclosures

All Authors: No reported disclosures

1235. Roles of Tetracyclines for Treatment of Stenotrophomonas maltophilia Pneumonia

Background

Stenotrophomonas maltophilia is a multidrug resistant organism with limited antibiotic treatment options. Sulfamethoxazole-trimethoprim (TMP-SMZ) is considered first line agent based on in vitro studies and clinical evidence. Minocycline has been showed to be active on in vitro studies and also has been explored in small retrospective studies However, doxycycline in the same class has variable in susceptibility in in vitro studies and has not been evaluated for efficacy in treatment of S. maltophilia infections The purpose of this research is to compare minocycline and doxycycline to TMP-SMZ for treatment of S. maltophilia pneumonia.

Methods

This retrospective, multi-center study evaluated hospitalized patients treated for S. maltophilia pneumonia with minocycline, doxycycline, or TMP-SMZ for clinical success, microbiologic success, and recurrence or reinfection within 30 days that required treatment. The inclusion criteria were patients ≥18 years old with S. maltophilia confirmed on respiratory culture from January 2013 to November 2020. Patients were classified as treatment with tetracyclines (minocycline or doxycycline) or TMP-SMZ based on definitive agent used for ≥50% of the treatment course and a minimum of four days. Patients with S. maltophilia resistant or intermediate to definitive therapy, and patients with combination therapy for treatment for S. maltophilia pneumonia were excluded.

Results

A total of 21 patients were included in tetracyclines group and 59 patients included in TMP-SMZ group. There was no difference in clinical success (28.6% vs. 25.4%; P = 0.994) or microbiologic success (n=28, 55.6% vs. 66.4%; P= 0.677) between tetracyclines and TMP-SMZ, respectively. Recurrence or reinfection requiring treatment (n=24) was higher in the tetracyclines group but not statistically significant compared to TMP-SMZ (66.7% vs. 26.7%; P= 0.092). A subgroup analysis showed no difference between doxycycline, minocycline, and TMP-SMZ for these three aims.

Conclusion

Clinical and microbiologic success were similar in patients treated with tetracyclines compared to TMP-SMZ for S. maltophilia pneumonia. This data suggests minocycline and doxycycline may be an option to treat S. maltophilia pneumonia, but conclusive clinical data continues to be lacking.

Disclosures

Anthony Gentene, PharmD, advisory board with Theravance Biopharma and Mylan (Consultant)

Use of MRI signal intensity ratio to differentiate between autoimmune pancreatitis and pancreatic ductal adenocarcinoma

AIM

To evaluate the accuracy of the lesion-to-erector spinae signal intensity ratio (SIR) on magnetic resonance imaging (MRI) for distinguishing autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDA).

MATERIALS AND METHODS

The MRI data of 21 patients with AIP and 27 patients with PDA were analysed retrospectively, and the signal intensity in pancreatic lesions and erector spinae muscles at the same level on T2-weighted imaging (T2WI), arterial phase (AP) imaging, and delayed phase (DP) imaging was measured for calculation of SIRs.

RESULTS

The mean SIRs of the pancreatic lesions and erector spinae from T2WI, AP, and DP images of AIP patients were 0.96, 1.27, and 1.42, respectively, while those of PDA patients were 1.35, 0.80, and 0.91, respectively. The differences in the SIRs between the AIP and PDA groups were statistically significant (p<0.001), with corresponding area under curve (AUC) values of 0.925, 0.906, and 0.961, respectively. The optimal cut-off values for the SIRs on T2WI, AP and DP images were 1.21, 1.01, and 1.08, respectively. SIR values < 1.21 on T2WI, >1.01 on AP imaging, and >1.08 on DP imaging identified AIP with sensitivities of 85.7%, 90.5%, and 90.5%, respectively, and specificities of 81.5%, 74.6%, and 81.5%, respectively. The AUC values for SIRs did not differ significantly between T2WI and DP imaging or AP and DP imaging (Z = 0.778, p=0.436; Z = 1.279, p=0.201).

CONCLUSION

The SIRs of pancreatic lesions and erector spinae on T2WI, AP, and DP images can be used to differentiate AIP from PDA.

Suprafascial plane endoscopy versus open carpal tunnel release for idiopathic carpal tunnel syndrome: Use of the Accordion Severity Grading System

This study aimed to assess the safety and effectiveness of modified endoscopic technique with a single portal from an external carpal tunnel approach for surgical operations in a suprafascial plane superficial to the transverse carpal ligament. Reversible nerve injury risk is threefold greater with a conventional endoscopic method than with open carpal tunnel release (OCTR), and this suprafascial plane endoscopic release (SPER) should circumvent the problem of hardware in the carpal tunnel encountered with the conventional endoscopic method and liable to cause iatrogenic damage to the median nerve. However, the surgical consequences of the new technique have not been studied. To fill this gap, a retrospective therapeutic study was conducted to compare negative outcomes versus open surgery. The Accordion Severity Grading System was used to grade complications from 0 to 3 according to necessity of treatment. Sequela and failure rates were also compared between the SPER and OCTR groups. Eighty-eight cases in 72 patients with idiopathic carpal tunnel syndrome (ICTS) met the inclusion criteria. SPER was performed in 28 hands in 27 patients, and OCTR in 60 hands in 49 patients. The results showed no significant difference in complication, sequela, or failure rates between groups (p > 0.05). Suprafascial plane endoscopic release, has certain advantages over the open method and was validated as a safe and effective method of treating ICTS.

Comparison of Ceftriaxone and Antipseudomonal β-Lactam Antibiotics Utilized for Potential AmpC β-Lactamase-Producing Organisms

Background: Induction of antibiotic resistance is associated with increased morbidity and mortality in AmpC β-lactamase producing Enterobacteriaceae. The use of ceftriaxone is controversial for treatment of these organisms due to concerns for inducible resistance. This study was designed to compare treatment failure rates between ceftriaxone and antipseudomonal β-lactam antibiotics when used as definitive therapy for organisms most commonly associated with chromosomal AmpC β-lactamase production. Methods: A retrospective, single-center cohort study was performed enrolling patients hospitalized with monomicrobial Enterobacter, Citrobacter, or Serratia spp. infections. The primary objective compared proportion of treatment failure between groups. All patients received either ceftriaxone or an antipseudomonal β-lactam alone within 24 hours of culture finalization, and with a duration of at least 72 hours for definitive treatment. Treatment failure was defined as either clinical failure (abnormal white blood cell count or temperature on day 7 or 14 post-antibiotics) or microbiologic failure (regrowth of the same organism at same site within 14 or 21 days). Results: Of 192 total patients, treatment failure was observed in 24/71 patients (34%) receiving ceftriaxone and in 42/121 patients (35%) receiving antipseudomonal β-lactam (P = .98). No difference was observed between clinical or microbiologic failure rates between groups. The ceftriaxone group had significantly more patients undergoing treatment for urinary tract infections (51% vs 17%, P < .001), but treatment failure rates remained similar between groups when comparing infections of all other sources. Conclusion: Ceftriaxone has comparable treatment failure rates to antipseudomonal β-lactams for susceptible Enterobacteriaceae infections and may be considered as a therapeutic option. Further, prospective research is needed to validate optimal dosing and application in all sites of infection.

[Anatomy of the deep circumflex iliac artery perforators and reconstruction of complex mandibular defects with chimeric deep circumflex iliac artery perforator flap]

OBJECTIVE

To investigate the anatomy of the perforator vessels of the deep circumflex iliac artery (DCIA) and the techniques for repairing mandibular complex defect using chimeric deep circumflex iliac artery perforator flap (DCIAPF).

OBJECTIVE

We analyzed the origin, distribution, number and courses of the perforator vessels of the DCIA, and measured the outside diameters of the vessels at the origin in 6 adult cadaveric specimens (12 sides) with latex perfusion. From July, 2018 to September, 2019, based on the results of anatomical study and imaging findings and using the digital surgical guide plate, we harvested DCIAPF from 4 patients for repairing mandibular body or angle defects and oral soft tissue defects.

OBJECTIVE

The perforating vessels of the DCIA included abdominal muscular branches, osteomusculocutaneous branches and terminal musculocutaneous branches. The abdominal muscle branches originated from the DCIA inguinal segment in 4 and from both the inguinal and iliac segments in 2 of the specimens. The osteomusculocutaneous branches all originated from the internal iliac crest in 75% and from both the inguinal and internal iliac crest segments in 25% of cases; the inguinal segment gave rise to only one perforating branch. The number of the musculocutaneous perforating branches was 1 (58.3%) or 2 (41.7%). In the 4 patients undergoing mandibular reconstruction, the DCIAPF survived in all cases with good recovery of the donor site wound. Satisfactory facial appearance with good oral morphology and occlusal relationship was achieved at 1 month postoperatively in all the patients. None of the patients experienced obvious functional abnormalities at the donor site, and imaging examination confirmed successful reconstruction of the oromandibular defects in all the cases.

OBJECTIVE

A good understanding of the anatomic characteristics of the perforator vessels of the DCIA combined with imaging examinations and digital surgery technology facilitates the harvest of DCIAPF for repairing mandibular body or angle defects complicated by oral soft tissue defects.

900. Retrospective Review of Microbiological profile in Post Surgical Spine Infections and Assess the Appropriateness of Current Pre-Op Antibiotic Prophylaxis Policy

Background

SSI is a devastating complication of spine surgery that results in significant morbidity as it requires prolonged antibiotic courses and multiple surgical debridements. It also increases the economic burden on the health care system. So, it becomes important to learn the microbiological profile and assess the current pro-op antibiotic prophylaxis policy.

Methods

All cases reported by the hospital infection control surveillance program based on CDC/NHSN Surveillance definitions between January 2017 and July 2019 were retrospectively reviewed for microbiological data and surgical characteristics using electronic medical record, and non-parametric test was used to assess the difference in proportional distribution of gram-negative organisms between upper and lower spine groups.

Results

Between January 2017 and July 2019, 3561 spine surgeries were performed, 51 cases of SSI were reported, and 50 patients have microbiological data available. The most commonly isolated organism was Staphylococcus aureus (38%), followed by Escherichia coli (12%). There was no statistical difference for the distribution of gram-negative organisms in upper spine (17) and lower spine (33) surgeries (29.4% vs 48.4%, P Value = 0.24). However total gram-negative organisms accounted for 42% cases and lower spine surgical procedures were more likely to be associated with mixed infections including both gram negative and gram-positive organisms (15.1% vs 0%). Cefazolin resistant gram-negative organisms accounted for 22% of all gram-negative infections. Our current pre-op antibiotic policy recommends cefazolin plus or minus vancomycin (If MRSA screen positive) and clindamycin plus vancomycin in patients with severe penicillin allergy.

Table 1: Characteristics of the cultures

Table: 2 Microorganisms isolated from 50 patients with post-surgical spine infections

Figure 1: Proportional distribution of Micro-organisms between lower and upper spine (Percentage on left side and No. of positive cultures on right side)

Conclusion

Although gram-positive organism predominated, there was a substantial portion of gram-negative organisms in post-surgical spine infections. Cefazolin would cover at least half of the gram-negative organisms identified based on our antibiogram susceptibility pattern. However, in patients with penicillin allergy, our current recommended pre-operative antibiotic prophylaxis does not provide gram-negative coverage. We will therefore explore the value of adding an agent with gram negative coverage based on our institutional antibiogram.

Disclosures

All Authors: No reported disclosures

Thin superficial inferior epigastric artery perforator flap for reconstruction of the tongue

The superficial inferior epigastric artery (SIEA) flap is widely used in the repair of large soft tissue defects of the extremities and in breast reconstruction. Because of the high fat content of the abdomen, it has been less used for glossectomy reconstruction. Here we present a series of seven patients who each underwent reconstruction with a thin SIEA flap after resection of the tongue. There were six men and one woman (mean age 48, range 24-66 years). All patients underwent preoperative computed tomographic (CT) angiography, and colour Doppler ultrasound (US) was used to select and map the most suitable SIEA. The flap was raised above the Scarpa's layer while adjusted the plane of dissection according to the specific needs for bulk in each case. All the flaps survived; one flap required a secondary anastomosis because of a venous anastomotic embolus. The size of flap used was 5.0cm×6.0cm - 7.0cm×9.0cm, and the flap was 0.8cm-1.4cm thick. The functional outcome was evaluated at 6 - 18 months follow up, when speech and swallowing were both good in all cases. The dissection above the pubic symphysis is an important refinement of the SIEA flap, and we conclude that the thin SIEA flap is a good choice for reconstruction after excision of cancer of the tongue.

Coping with COVID-19: ventilator splitting with differential driving pressures using standard hospital equipment

The global COVID‐19 pandemic has led to a worldwide shortage of ventilators. This shortage has initiated discussions on how to support multiple patients with a single ventilator (ventilator splitting). Ventilator splitting is incompletely tested, experimental and the effects have not been fully characterised. This study investigated the effect of ventilator splitting on system variables (inspiratory pressure, flow and volume) and the possibility of different ventilation targets for each limb using only standard hospital equipment. Experiments were conducted on two test lungs with different compliances (0.02 l.cmH₂O⁻¹ and 0.04 l.cmH₂O⁻¹). The ventilator was used in both pressure and volume control modes and was set to ventilate the low compliance lungs at end‐tidal volumes of 500 ± 20 ml. A flow restrictor apparatus consisting of a Hoffman clamp and tracheal tube was connected in series to the inspiratory limb of the high compliance test lungs and the resistance modified to achieve end‐tidal volumes of 500 ± 20 ml. The restriction apparatus successfully modified the inspiratory pressure, minute ventilation and volume delivered to the high compliance test lungs in both pressure control (27.3–17.8 cmH₂O, 15.2–8.0 l.min⁻¹ and 980–499 ml, respectively) and volume control (21.0–16.7 cmH₂O, 10.7–7.9 l.min⁻¹ and 659–498 ml, respectively) ventilation modes. Ventilator splitting is not condoned by the authors. However, these experiments demonstrate the capacity to simultaneously ventilate two test lungs of different compliances, and using only standard hospital equipment, modify the delivered pressure, flow and volume in each test lung.

Alveolar heparan sulfate shedding impedes recovery from bleomycin-induced lung injury

The pulmonary epithelial glycocalyx, an anionic cell surface layer enriched in glycosaminoglycans such as heparan sulfate and chondroitin sulfate, contributes to the alveolar barrier. Direct injury to the pulmonary epithelium induces shedding of heparan sulfate into the air space; the impact of this shedding on recovery after lung injury is unknown. Using mass spectrometry, we found that heparan sulfate was shed into the air space for up to 3 wk after intratracheal bleomycin-induced lung injury and coincided with induction of matrix metalloproteinases (MMPs), including MMP2. Delayed inhibition of metalloproteinases, beginning 7 days after bleomycin using the nonspecific MMP inhibitor doxycycline, attenuated heparan sulfate shedding and improved lung function, suggesting that heparan sulfate shedding may impair lung recovery. While we also observed an increase in air space heparanase activity after bleomycin, pharmacological and transgenic inhibition of heparanase in vivo failed to attenuate heparan sulfate shedding or protect against bleomycin-induced lung injury. However, experimental augmentation of airway heparanase activity significantly worsened post-bleomycin outcomes, confirming the importance of epithelial glycocalyx integrity to lung recovery. We hypothesized that MMP-associated heparan sulfate shedding contributed to delayed lung recovery, in part, by the release of large, highly sulfated fragments that sequestered lung-reparative growth factors such as hepatocyte growth factor. In vitro, heparan sulfate bound hepatocyte growth factor and attenuated growth factor signaling, suggesting that heparan sulfate shed into the air space after injury may directly impair lung repair. Accordingly, administration of exogenous heparan sulfate to mice after bleomycin injury increased the likelihood of death due to severe lung dysfunction. Together, our findings demonstrate that alveolar epithelial heparan sulfate shedding impedes lung recovery after bleomycin.

Discrimination between Glioblastoma and Solitary Brain Metastasis: Comparison of Inflow-Based Vascular-Space-Occupancy and Dynamic Susceptibility Contrast MR Imaging

BACKGROUND AND PURPOSE

Accurate differentiation between glioblastoma and solitary brain metastasis is of vital importance clinically. This study aimed to investigate the potential value of the inflow-based vascular-space-occupancy MR imaging technique, which has no need for an exogenous contrast agent, in differentiating glioblastoma and solitary brain metastasis and to compare it with DSC MR imaging.

MATERIALS AND METHODS

Twenty patients with glioblastoma and 22 patients with solitary brain metastasis underwent inflow-based vascular-space-occupancy and DSC MR imaging with a 3T clinical scanner. Two neuroradiologists independently measured the maximum inflow-based vascular-space-occupancy-derived arteriolar CBV and DSC-derived CBV values in intratumoral regions and peritumoral T2-hyperintense regions, which were normalized to the contralateral white matter (relative arteriolar CBV and relative CBV, inflow-based vascular-space-occupancy relative arteriolar CBV, and DSC-relative CBV). The intraclass correlation coefficient, Student t test, or Mann-Whitney U test and receiver operating characteristic analysis were performed.

RESULTS

All parameters of both regions had good or excellent interobserver reliability (0.74∼0.89). In peritumoral T2-hyperintese regions, DSC-relative CBV (P < .001), inflow-based vascular-space-occupancy arteriolar CBV (P = .001), and relative arteriolar CBV (P = .005) were significantly higher in glioblastoma than in solitary brain metastasis, with areas under the curve of 0.94, 0.83, and 0.72 for discrimination, respectively. In the intratumoral region, both inflow-based vascular-space-occupancy arteriolar CBV and relative arteriolar CBV were significantly higher in glioblastoma than in solitary brain metastasis (both P < .001), with areas under the curve of 0.91 and 0.90, respectively. Intratumoral DSC-relative CBV showed no significant difference (P = .616) between the 2 groups.

CONCLUSIONS

Inflow-based vascular-space-occupancy has the potential to discriminate glioblastoma from solitary brain metastasis, especially in the intratumoral region.

Out of Sight-Out of Mind: Impact of Cascade Reporting on Antimicrobial Usage

Background

There is a paucity of data evaluating the strategy of suppressing broader-spectrum antibiotic susceptibilities on utilization. Cascade reporting (CR) is a strategy of reporting antimicrobial susceptibility test results in which secondary (eg, broader-spectrum, costlier) agents may only be reported if an organism is resistant to primary agents within a particular drug class. Our objective was to evaluate the impact of ceftriaxone-based cascade reporting on utilization of cefepime and clinical outcomes in patients with ceftriaxone-susceptible Escherichia and Klebsiella clinical cultures.

Methods

We compared post-CR (July 2014-June 2015) with baseline (July 2013-June 2014), evaluating utilization of cefepime, cefazolin, ceftriaxone, ampicillin derivatives, fluoroquinolones, piperacillin/tazobactam, ertapenem, and meropenem; new Clostridium difficile infection; and length of stay (LOS) after the positive culture, 30-day readmission, and in-hospital all-cause mortality.

Results

Mean days of therapy (DOT) among patients who received any antibiotic for cefepime decreased from 1.229 days during the baseline period to 0.813 days post-CR (adjusted relative risk, 0.668; P < .0001). Mean DOT of ceftriaxone increased from 0.864 days to 0.962 days, with an adjusted relative risk of 1.113 (P = .004). No significant differences were detected in other antibiotics including ertapenem and meropenem, demonstrating the direct association of the decrease in cefepime utilization with CR based on ceftriaxone susceptibility. Average LOS in the study population decreased from 14.139 days to 10.882 days from baseline to post-CR and was found to be statistically significant (P < .0001).

Conclusions

In conclusion, we demonstrated significant association of decreased cefepime utilization with the implementation of a CR based on ceftriaxone susceptibility. We demonstrated the safety of deescalation, with LOS being significantly lower during the post-CR period than in the baseline period, with no change in in-hospital mortality.

[Risk factors of human cystic echinococcosis in Shiqu County Sichuan Province: a case-control study]

OBJECTIVE

To identify the main risk factors of human cystic echinococcosis in Shiqu County, Sichuan Province, so as to provide the reference for the formulation of echinococcosis control strategies in Shiqu County.

METHODS

During the period from November 2015 through June 2017, the patients with cystic echinococcosis (case group) and healthy controls (control group) were randomly sampled from Shiqu County as the study subjects. A questionnaire survey was conducted to capture the study subjects'age, gender, ethnicity, occupation, religion, lifestyle, education level, number of household dogs, bovine and sheep, and density of dog feces in the courtyard. The major risk factors of human cystic echinococcosis were identified using a logistic regression model.

RESULTS

Univariate logistic regression analysis showed 7 risk factors with statistical significance between the case and control groups, and age, lifestyle, number of household bovine, number of household sheep, number of house-hold dogs, and the density of dog feces in the courtyard were included in the multivariate logistic regression model (OR = 1.026, 4.792, 1.067, 1.022, 1.709 and 1.095, respectively).

CONCLUSIONS

High age, pastoral nomadic lifestyle, high number of house-hold bovine, high number of household sheep, high number of household dogs and high density of dog feces in the courtyard are strongly associated with the riks of human cystic echinococcosis in Shiqu County.

Effects of progesterone receptor on proliferation of uterine leiomyoma cells

In order to study the mechanism of the effect of progesterone receptor on the growth of primary uterine leiomyoma cells, the primary cells were extracted from uterine leiomyoma cells and identified by immunohistochemistry (IHC). Mitochondrial progesterone receptor-positive [PR-M(+)], mitochondrial progesterone receptor-negative [PR-M(-)], progesterone receptor A (PR-A) and progesterone receptor B (PR-B) were screened by Western blotting. Different concentrations of Mifepristone (MIF), a progesterone receptor antagonist, were used to interfere with PR-M(+) and PR-M(-) cell lines, respectively. Proliferation and apoptosis of PR-M(+) and PR-M(-) cell lines were detected by tetramethylazolyl blue method and flow cytometry, respectively. The expression of Caspase-3 and B-cell lymphoma 2 (Bcl-2) protein was detected by Western blotting. The results showed that the growth of PR-M(+) and PR-M(-) uterine leiomyoma cells was inhibited with the increase of MIF concentration. Furthermore, the proliferation inhibition rate and apoptosis rate were gradually increased. However, the expression of Caspase-3 protein on progesterone receptor M increased, while the expression of Bcl-2 decreased. Moreover, progesterone could induce progesterone receptor M to up-regulate apoptotic protein Caspase-3 and down-regulate anti-apoptotic protein Bcl-2, thus it could inhibit the apoptosis of primary cultured uterine leiomyoma cells and promote the proliferation of leiomyoma cells.

Effects of progesterone receptor on proliferation of uterine leiomyoma cells

In order to study the mechanism of the effect of progesterone receptor on the growth of primary uterine leiomyoma cells, the primary cells were extracted from uterine leiomyoma cells and identified by immunohistochemistry (IHC). Mitochondrial progesterone receptor-positive [PR-M(+)], mitochondrial progesterone receptor-negative [PR-M(-)], progesterone receptor A (PR-A) and progesterone receptor B (PR-B) were screened by Western blotting. Different concentrations of Mifepristone (MIF), a progesterone receptor antagonist, were used to interfere with PR-M(+) and PR-M(-) cell lines, respectively. Proliferation and apoptosis of PR-M(+) and PR-M(-) cell lines were detected by tetramethylazolyl blue method and flow cytometry, respectively. The expression of Caspase-3 and B-cell lymphoma 2 (Bcl-2) protein was detected by Western blotting. The results showed that the growth of PR-M(+) and PR-M(-) uterine leiomyoma cells was inhibited with the increase of MIF concentration. Furthermore, the proliferation inhibition rate and apoptosis rate were gradually increased. However, the expression of Caspase-3 protein on progesterone receptor M increased, while the expression of Bcl-2 decreased. Moreover, progesterone could induce progesterone receptor M to up-regulate apoptotic protein Caspase-3 and down-regulate anti-apoptotic protein Bcl-2, thus it could inhibit the apoptosis of primary cultured uterine leiomyoma cells and promote the proliferation of leiomyoma cells.

159. Comparing Clinical Cure and Patient Outcomes Between Intravenous Therapy and Intravenous (IV)-to-Oral (PO) Step-down Therapy for Treatment of Gram-Negative Bloodstream Infections

Background

There is a paucity of evidence surrounding optimal prescribing practices for the treatment of Gram-negative bloodstream infections (GNBSI). This study aimed to assess the appropriateness of IV-to-PO step-down therapy in the treatment of GNBSI.

Methods

A retrospective cohort study was conducted at the University of Cincinnati Medical Center and West Chest Hospital and included subject’s ≥18 years of age with GNBSI caused by Enterobacteriaceae spp. or Pseudomonas aeruginosa. The primary objective was to compare clinical cure rates between IV-only and IV-to-PO therapy, and to further assess differences in clinical cure rates amongst oral antibiotics of high, moderate, and low bioavailability. The study also aimed to identify factors associated with clinical cure, hospital length of stay, and emergence of multi-drug-resistant organisms (MDRO).

Results

Amongst 215 subjects screened, 99 subjects were included and 64 subjects met criteria for clinical cure. In the univariate analysis, the IV-to-PO group had a higher percentage of clinical cure than IV only therapy (82% vs. 48%, P = 0.001). Of note, the two study groups were significantly different in regards to intensive care status, Pitt bacteremia score, and primary site of infection. Upon further analysis, data from the multivariate logistic regression revealed that critical illness was the only significant factor that negatively impacted clinical cure (OR = 0.208; 95% CI 0.04–0.99; P = 0.049). A total of 49 subjects received oral antibiotics. Majority of patients (82%) in the IV-to-PO group received a moderately bioavailable oral antibiotic. No difference in respect to clinical cure rate was found between the three PO antibiotic bioavailability groups (P = 0.346). The median duration of hospital stay was shorter in the IV-to-PO compared with IV alone group (4 days vs. 9.5 days, respectively, P ≤ 0.001). There was a trend in emergence of MDROs with IV therapy compared with IV-to-PO therapy (10% vs. 2%, P = 0.204).

Conclusion

IV-to-PO stepdown therapy compared with IV therapy alone was noninferior in clinical cure rates in the treatment of GNBSI and may result in fewer hospital days and less emergence of multidrug-resistant organisms. These conclusions are limited by significant differences in severity of illness between groups in this study.

Disclosures

All authors: No reported disclosures.

Crystal Structure of the PX Domain of SNX27

SNX27 is a component of the retromer complex essential for the recycling of transmembrane receptors. SNX27 contains the N-terminal Phox (PX) domain that binds inositol 1,3-diphosphate (Ins(1,3)P₂) and is important for the SNX27 localization. Here, we determined the crystal structure of human SNX27 PX domain by X-ray crystallography. We found that the sulfate ion is located in the positively charged lipid-binding pocket of the PX domain, which mimics the phospholipid recognition. In addition, we modelled the SNX27-PX-Ins(1,3)P₂ complex to better understand the mechanism of Ins(1,3)P₂ recognition by the PX domain of SNX27.

Abstract PD1-08: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: LSZ102 is an orally bioavailable SERD that inhibits ER gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This study is evaluating LSZ102 as a single agent and in combination with the CDK 4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with ER+ ABC. The LSZ102 single agent data are presented below; combination data are not discussed.

Methods: In the dose-escalation phase evaluating single-agent LSZ102 (Arm A), pts (age ≥18 years; ECOG PS 0-1) with histologically confirmed ER+ ABC and progression on endocrine therapy (ET) received LSZ102. The starting dose was 200 mg once daily. The primary objective of Arm A was to characterize the safety and tolerability of LSZ102 and identify a recommended dose for expansion (RDE). Secondary objectives included preliminary antitumor activity and pharmacokinetics (PK).

Results: As of January 22, 2018, 57 pts were enrolled to Arm A (LSZ102 200 mg, n=4; 400 mg, n=6; 450 mg fasted, n=15; 450 mg with food, n=6; 600 mg, n=20; 900 mg, n=6). Median age was 60 years, 75% (n=43) of pts had an ECOG PS of 0, 56% (n=32) had received prior fulvestrant, and 58% (n=33) had received prior CDK4/6 inhibitors; median number of prior lines of therapy (all settings) was 6. At data cut-off, 48 pts had discontinued treatment, most (n=45, 94%) due to disease progression. Dose-limiting toxicities across treatment groups included diarrhea (2 pts in the 900-mg group), vomiting (1 pt in the 600-mg group), and AST and ALT elevation (1 pt in the 450-mg with food group). The most common treatment-related adverse events (AEs) in the treatment period were diarrhea (60%), nausea (56%), and vomiting (30%). In the treatment period, treatment-related grade 3 AEs (12%) were infrequent, and there were no such grade 4 events. Six pts (11%) required dose reduction due to AEs (nausea, vomiting or diarrhea); 4/6 of the dose reductions occurred at 900 mg. Preliminary PK assessment showed rapid absorption and dose-proportional increases in LSZ102 exposure; trough concentrations were above the predicted tumorostatic concentrations at doses of ≥400 mg. Based on PK results for the 450-mg fasted and fed cohorts, LSZ102 exposure does not appear to be affected by dosing with a regular meal. Evidence of ER modulation by immunohistochemistry was observed in paired baseline and on-treatment biopsies. 18F-fluoroestradiol positron emission tomography (FES-PET) analysis (n=6) demonstrated abrogation of FES-PET signal for pts in the 450-mg and 600-mg dose groups. Seventeen pts (29.8%) had a best response of stable disease, and 1 pt, who happened to be in the 600-mg group, achieved a partial response.

Conclusion: In heavily pretreated pts, LSZ102 was well tolerated, demonstrated antitumor activity, and achieved effective exposure levels based on PK and pharmacodynamics. Food intake did not appear to significantly alter the PK profile of LSZ102. Dose escalation for LSZ102 in combination with ribociclib or alpelisib is ongoing and will be reported in a future analysis. An update on the recommended single agent dose and schedule will be presented.

Citation Format: Jhaveri K, Curigliano G, Yap Y-S, Cresta S, Duhoux FP, Terret C, Takahashi S, Ulaner GA, Kundamal N, Baldoni D, Liao S, Crystal A, Juric D. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-08.

Abstract OT1-03-01: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: Although ET remains the basis of therapy for ER+, HER2– ABC, treatment resistance frequently occurs. Novel strategies to target the receptor and/or alternative pathways to overcome therapeutic resistance are under investigation. LSZ102 is a novel, orally bioavailable, nonsteroidal SERD. Preclinically, LSZ102 inhibits ER gene transcription, induces receptor degradation, blocks ER-dependent cell growth, and has synergistic activity with the phosphoinositide 3-kinase (PI3K)-alpha inhibitor alpelisib (BYL719). The present study is evaluating the safety and tolerability of LSZ102 plus alpelisib in patients with ER+, HER2– ABC with progression on ET.

Trial Design: This phase 1/1b, open-label study is enrolling ˜18-30 patients (men and women of any menopausal status) in Arm C of the dose-escalation part of the study, which investigates the combination of LSZ102 and alpelisib; additional study arms will investigate LSZ102 as a single agent or in combination with ribociclib. Enrollment in Arm C started after identification of a safe and tolerable single-agent dose for LSZ102. Alpelisib dosing began at 200 mg/day and will not be escalated beyond the maximum tolerated dose (MTD) determined in the alpelisib single-agent arm of study CBYL719X2101 (400 mg/day). Dose escalation of alpelisib in combination with LSZ102 is guided by BLRM and integrates Cycle 1 DLT rates, lower grade and later cycle AE, PK, PD and preliminary activity to identify a recommended dose for expansion (RDE). Patients will receive treatment until disease progression, unacceptable toxicity, or withdrawal of consent. For inclusion in the study, patients must have histologically confirmed ER+, HER2– ABC and disease progression after ET for ABC or recurrence on/within 12 months of completion of adjuvant ET. In the escalation part of the study, patients are eligible regardless of PIK3CA status. Premenopausal women must receive concomitant treatment with a gonadotropin-releasing hormone agonist. Eligible patients must have adequate bone marrow and organ function, Eastern Cooperative Oncology Group performance status of 0 or 1, and have completed and recovered from acute toxicities of radiotherapy and/or prior anticancer therapy. Exclusion criteria include symptomatic central nervous system metastases, clinically significant cardiac disease or impaired cardiac function (including a QT interval corrected for heart rate using Fridericia's formula [QTcF] &gt;460 ms in women or &gt;450 ms in men), uncontrolled diabetes mellitus type II (or type I), and prior treatment with a PI3K inhibitor. The primary objectives are characterization of safety and tolerability for the combination and identification of a recommended dose. Secondary objectives include characterization of pharmacokinetic properties and pharmacodynamic effects. Recruitment for Arm C is ongoing. NCT02734615

Citation Format: Curigliano G, Cresta S, Yap Y-S, Juric D, Duhoux FP, Terret C, Takahashi S, Layman RM, Kundamal N, Baldoni D, Liao S, Crystal A, Jhaveri K. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT1-03-01.

De novo mutations of STXBP1 in Chinese children with early onset epileptic encephalopathy

To detect syntaxin-binding protein 1 (STXBP1) mutations in Chinese patients with early onset epileptic encephalopathy (EOEE) of unknown etiology. Targeted next-generation sequencing was used to identify STXBP1 mutations in 143 Chinese patients with EOEE of unknown etiology. A filtering process was applied to prioritize rare variants of potential functional significance. Then Sanger sequencing was employed to validate the parental origin of the variants. Detailed clinical and genetic data were collected for 9 STXBP1-positive patients. Eight de novo heterozygous STXBP1 mutations were identified in 9 patients; 5 were novel mutations (c.1155delC, c.1030-1G>A, c.217G>C, c.268G>C, c.1480_1481 insT) and 3 were previously reported (c.1216C> T, c.1217G>A [2 cases], c.875G>A). Two patients had Ohtahara syndrome and 1 had West syndrome at onset, whereas the other 6 presented with EOEE that did not fit a specific recognized epilepsy syndrome. Six of these patients later evolved to West syndrome. All but 2 cases were prescribed more than 2 antiepileptic drugs (AEDs) plus other regimens. Four subjects showed good responses to levetiracetam (LEV) alone or in combination with other AEDs, and one case (1/3) achieved complete freedom from seizures with a ketogenic diet (KD). All patients exhibited severe to profound global developmental delay. Five novel heterozygous de novo STXBP1 mutations were discovered in patients with EOEE from China. STXBP1 mutational analysis should be performed in cases of EOEE of unknown etiology. LEV as monotherapy or adjunctive therapy with other regimens, as well as KD should be considered for management of this patient group.

Trends in drug-resistant tuberculosis in China: data from a clinical tuberculosis centre

OBJECTIVE

To describe the trends in prevalence of drug-resistant tuberculosis (TB) among in-patients in Beijing Chest Hospital, Beijing, China, using a 10-year retrospective study.

DESIGN

From 2005 to 2014, 18 310 in-patients with TB were recruited for the study, most of whom were referrals; no distinction was made between new and previously treated cases. Drug susceptibility testing (DST) was performed in culture-positive cases using the proportion method to determine multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Risk factors associated with drug resistance were identified.

RESULTS

A total of 5141 (28.0%) samples were culture-positive. DST results showed that 860 (16.7%) cases were MDR-TB and 176 (3.4%) were XDR-TB. MDR-TB and XDR-TB were detected in respectively 21.2% and 12.5% of new cases. The rate of MDR-TB and XDR-TB gradually increased from 2005, with MDR-TB reaching a peak in 2008 and XDR-TB in 2009. These data closely mirror national survey data on this region, patient age and occupation.

CONCLUSION

Trends in MDR-TB and XDR-TB prevalence during the past decade and their inflection points were determined, which complemented reports from previous national surveys. This information is useful for fighting TB in China.

Effects of fat supplementation on plasma glucose, insulin and fatty acid analysis in ponies maintained on a forage-based diet

The objective of this study was to observe how fat incorporated into an equine forage-based diet through supplementation altered levels of plasma glucose, insulin and fatty acids. Five Shetland/Hackney cross pony mares were fed alfalfa pellet diets top dressed with commercially available vegetable oil (blend of soya bean, canola and corn oils) at 0%, 5%, 10% or 15% of diet. Ponies were randomly assigned one of four diets to start, with a 14-day adjustment period between transitioning to another one of the four diets. Ponies were gradually adapted to the new diet within the 14-day period before a five-day trial period. Each pony received all four diets by the end of the study. Each trial was a five-day period with a three-day sample collection. Blood samples for each collection week were taken 0, 30, 60, 90, 120, 150, 180, 210, 240 and 270 min and at 5, 6, 7, 8, 9 and 10 hr post-feeding. Excess fat did not impact plasma glucose (p > .1), nor did it affect blood plasma insulin concentration. While there was no time alteration found for plasma fatty acid concentration (p > .1), C14:0 increased when ponies were fed 0% fat and C18:2 decreased when ponies were fed 0% fat. Plasma fatty acids (% of total FA) were higher in C18:0, C18:1, C18:2 and C20:1 in the added fat diets (p < .1). These findings suggest the amounts reported in this study of fat supplementation on a forage-based diet did influence the fatty acid analysis within the pony, but did not negatively impact blood glucose and insulin concentrations.

Abstract P5-21-04: Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ breast cancer

Background: LSZ102 is an orally bioavailable selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This Phase I/Ib, open-label study is evaluating LSZ102 as a single agent and in combination with the CDK4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with locally advanced/metastatic ER-positive (ER+) breast cancer (BC).

Methods: The primary objective is to characterize the safety and tolerability, and identify a recommended dose and regimen of LSZ102 alone (Arm A) or in combination with ribociclib (Arm B) or alpelisib (Arm C). Secondary objectives include evaluation of preliminary antitumor activity and pharmacokinetics (PK). Eligible pts (aged ≥18 yrs; ECOG PS 0-1) have histologically confirmed ER+ BC that has progressed after endocrine therapy.

Results: As of March 14, 2017, dose escalation evaluating 16 pts in Arm A (LSZ102 200 mg [n=4], 400 mg [n=6], and 600 mg [n=6]) had completed (median age 57.5 yrs; 81% ECOG PS 0; 63% received prior fulvestrant). Five pts (median age 59.0 yrs; 80% ECOG PS 0; 60% received prior fulvestrant) had enrolled in the first cohort of Arm B (LSZ102 200 mg QD + ribociclib 300 mg 3 weeks on/1 week off) with evaluation ongoing. Arm C (LSZ102 + alpelisib) had yet to open. As of March 14, 2017, 9/16 (56%) pts in Arm A had discontinued treatment, all due to progressive disease (PD); in Arm B all pts were still receiving treatment. There were no dose-limiting toxicities in either arm at the dose levels evaluated; dose escalation is ongoing. The most common drug-related adverse events (AEs) were diarrhea (Grade [Gr] 1: 7/16; Gr 2: 2/16 pts), nausea (Gr 1: 6/16; Gr 2: 2/16 pts), and vomiting (Gr 1: 3/16 pts) in Arm A, and hot flush, nausea, vaginal discharge (all Gr 1: 2/5 pts), thrombocytopenia (Gr 1: 1/5; Gr 2: 1/5 pts), and neutropenia (Gr 2: 1/5, Gr 3: 1/5 pts) in Arm B. There were no drug-related Gr 3/4 AEs reported in Arm A; in Arm B, Gr 3 neutropenia, leukopenia, and lymphopenia each occurred in 1/5 pts. Preliminary PK assessment showed single-agent LSZ102 exposure increased dose-proportionally from 200 to 600 mg QD. In combination with ribociclib, exposures were consistent with those of the single agent at the same dose. In Arm A, preliminary evidence of antitumor activity was observed. Efficacy data for Arms B and C were not available as of March 14, 2017. One pt, whose tumor harbored an ESR1 D538G mutation, had been treated with multiple prior therapies in the metastatic setting, including letrozole, exemestane, tamoxifen, exemestane + everolimus, and anastrozole, as well as fulvestrant for 120 days prior to PD, and letrozole + palbociclib for 94 days prior to PD. As of March 14, 2017, this pt had been on LSZ102 treatment (400 mg QD) for 167 days, with a best response of stable disease (14% reduction in sum of diameter of target lesions).

Conclusions: Oral single-agent LSZ102 appears well-tolerated, with a manageable safety profile. Preliminary data also suggest tolerability when combined with ribociclib. Preliminary evidence of single-agent antitumor activity was seen in heavily pretreated pts with ER+ BC in a post-fulvestrant setting.

Citation Format: Juric D, Curigliano G, Cresta S, Yap Y-S, Terret C, Duhoux FP, Takahashi S, Kundamal N, Bhansali S, Liao S, Crystal A, Jhaveri K. Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-04.

Expression of BrpA in Streptococcus mutans is regulated by FNR-box mediated repression

Our previous studies showed that brpA in Streptococcus mutans, which encodes a member of the LytR-CpsA-Psr family of proteins, can be co-transcribed with brpB upstream as a bicistronic operon, and the intergenic region also has strong promoter activity. To elucidate how brpA expression is regulated, the promoter regions were analyzed using polymerase chain reaction-based deletions and site-directed mutagenesis and a promoterless luciferase gene as a reporter. Allelic exchange mutagenesis was also used to examine genes encoding putative trans-acting factors, and the impact of such mutations on brpA expression was analyzed by reporter assays. Multiple elements in the short brpA promoter (nucleotide -1 to -344 relative to start cordon ATG) were shown to have a major impact on brpA expression, including an FNR-box, for a putative binding site of an FNR-type of transcriptional regulator. When compared with the intact brpA promoter, mutations of the highly conserved nucleotides in FNR-box from TTGATgtttAcCtt to TTACAgaaaGtTac resulted in 1362-fold increases of luciferase activity (P < .001), indicative of the FNR-box-mediated repression as a major mechanism in regulation of brpA expression. When luciferase reporter was fused to the upstream brpBA promoter (nucleotides -784 to -1144), luciferase activity was decreased by 4.5-fold (P < .001) in the brpA mutant, TW14D, and by 67.7-fold (P < .001) in the brpB mutant, JB409, compared with the wild-type, UA159. However, no such effects were observed when the reporter gene was fused to the short brpA promoter and its derivatives. These results also suggest that brpA expression in S. mutans is auto-regulated through the upstream brpBA promoter.

[Prostaglandin-associated periorbitopathy]

Glaucoma is one of the leading causes of blindness in the world, second to cataract. The treatment of glaucoma mainly includes drugs, laser and operation, which can slow down the progress of the disease. Prostaglandin is the first-line medication at present. With the constant promotion of clinical application, the local side effects have been found, such as conjunctival congestion, lash lengthening, periorbital and iris pigment deepening, blepharitis and macular edema. As people pay more attention to appearance, periorbitopathy caused by prostaglandin has been reported in recent years, including upper eyelid ptosis and dermatochalasis, deepening of the upper eyelid sulcus, periorbital fat loss, enophthalmos and inferior scleral exposure. The mechanism, performance and treatment methods of these prostaglandin-associated periorbitopathies are reviewed. (Chin J Ophthalmol, 2017, 53: 637-640).

Quantitative structure-activity relationship study of amide mosquito repellents

A quantitative structure-activity relationship (QSAR) study on 43 amide repellents was carried out by the heuristic method in order to reveal the correlations between molecular parameters of these amides and their repellency against Aedes aegypti. Sketches and optimizations of molecular structures were achieved by the Gaussian software package. Generation and screening of molecular parameters were accomplished using CODESSA 2.7.10 software. The leave-one-out method was applied for the model validation. The results showed that a four-descriptor QSAR model with r² of 0.897 was obtained. The average r² values of the training set and test set of the QSAR model were 0.901 and 0.863, respectively, which suggested that the stability and predictability of the model were confirmed. Analysis of the implications of the descriptors that constitute the QSAR model indicated that all the descriptors were related to the charge distribution over the molecule and affect the dipole moment of the repellents.

Mediating effect of coping styles on the association between psychological capital and psychological distress among Chinese nurses: a cross-sectional study

WHAT IS KNOWN ON THE SUBJECT?: Studies show that psychological capital (PsyCap) is a protective factor against psychological distress, such as depressive symptoms. However, few have attempted to address the role of coping styles in the relationship between PsyCap and psychological distress. WHAT DOES THIS PAPER ADD TO EXISTING KNOWLEDGE?: Our study found moderate levels of PsyCap among nurses in China. Among the subcategories of PsyCap, optimism and hope were most highly correlated with psychological distress. Psychological distress was positively associated with negative coping and negatively associated with positive coping. This study confirmed the partial mediating effect of coping styles in PsyCap and psychological distress among Chinese nurses. In other words, this study found direct and indirect effects of PsyCap on psychological distress mediated via coping styles. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: The significant mediating effect of negative and positive coping styles between PsyCap and psychological distress has implications for hospital administrators, especially nurse leaders. Effective strategies should be implemented to improve PsyCap and coping styles among Chinese nurses, and alleviate psychological distress. Optimism and hope should be emphasized in PsyCap investment. Different styles of coping are influenced and modified by teaching and experience. Therefore, it is essential that nurse managers organize educational and training programmes to provide nurses with relative coping knowledge and techniques, and improve their coping ability. Several studies suggest that coping styles are affected by social support. Thus, nurse managers should assist nurses with social support and enhance coping strategies to reduce psychological distress.

ABSTRACT

Introduction PsyCap includes four categories namely self-efficacy, hope, optimism and resilience. Research has demonstrated that PsyCap and coping styles affect current psychological distress. Nevertheless, few studies have explored the role of coping styles in PsyCap and psychological distress. Aim This study investigated the role of coping styles as a mediator in PsyCap and psychological distress among Chinese nurses. Methods Participants included 538 nurses who completed self-report questionnaires assessing PsyCap, coping styles and psychological distress. Linear regression analyses were used to explore the role of coping styles. Results PsyCap, coping styles and psychological distress were significantly correlated. Among the subcategories of PsyCap, optimism and hope were most highly correlated with psychological distress. Coping styles is a partial mediator of PsyCap and psychological distress. Implications for mental health nursing The significant role of negative and positive coping styles in PsyCap and psychological distress has implications for hospital administrators, especially nurse leaders. Effective strategies should be implemented to improve PsyCap and coping styles among Chinese nurses, to alleviate psychological distress. Optimism and hope should be the focus of the improvement. Different styles of coping are developed from education and experience. Therefore, it is necessary for nurse managers to organize educational and training programmes to improve coping skills among nurses. Studies suggest that coping styles are affected by social support. Thus, nurse managers should also assist nurses with social support and enhance coping strategies to reduce psychological distress.

68 GROWTH AND MARKET QUALITY OF PIGS BORN FROM MAGNETIC NANOPARTICLE-TREATED BOAR SPERMATOZOA

Sperm ejaculates contain a heterogeneous population of nonviable and viable spermatozoal cells. Ejaculates with high concentrations of poor quality or damaged spermatozoa can greatly impair the overall fertility of males. Recently, a novel technique termed nanopurification has been developed (Feugang et al. 2015 IVF Reprod. Med. Genet. 3, 2) to noninvasively target and remove poor quality spermatozoa from boar semen. Such removal will enrich insemination doses with high quality spermatozoa to enhance fertility successes. However, effects associated with offspring born from nanopurified semen and possible meat quality assurance have yet to be extensively studied. The objective of this study was to measure the growth performance and market characteristics of pigs born from standard or nanopurified spermatozoa. Boar semen was obtained in insemination doses from a local stud and was mixed with (nanopurified) magnetic nanoparticles (iron-oxide) specifically designed to interact with acrosome-reacted and apoptotic spermatozoa. After incubation, mixed semen were placed under an electromagnetic field trapping moribund sperm to allow collection of intact and viable spermatozoa. Six gilts were bred with standard non-purified (control; n = 3) or nanopurified (n = 3) semen, with subsequent pregnancies leading to full-term birth of viable offspring. At weaning, pigs of equal sexes (5 male and 5 female) were randomly selected from control (n = 10) and nanopurified (n = 10) litters. Pigs were fed and measured until market weight, at which meat quality and carcass characteristics were assessed. Data (mean ± SEM) were analysed with Student’s t-test and SAS software (SAS Institute Inc., Cary, NC, USA). The threshold of significance was set as P < 0.05. Patterns of growth between groups were comparable up to market size (P > 0.05). Standard pork quality parameters (lean carcass weight, loin eye area, percentage of lean cuts, loin and ham colouring, etc.) revealed no significant differences between groups (P > 0.05). Dressing percentage was found higher in the nanopurified group compared with control, with a 1.5% increase (P < 0.05). Marbling score tended to be significantly higher in the nanopurified group (2.7 ± 0.15) when compared with the control (2.3 ± 0.15). Findings indicate that sperm nanopurification does not impair growth of offspring and could ultimately lead to a higher pork carcass quality. Additional research is being conducted to confirm current findings and identify further effects of nanopurification regarding offspring and carcass quality. This work was supported by USDA-ARS Grant #58–6402–3-018.

64 EFFECTS OF NANOPURIFIED BOAR SEMEN FOR ARTIFICIAL INSEMINATION ON PROTEIN DETECTION IN SWINE OFFSPRING MUSCLE AND FAT TISSUE

Standard extended semen contains both viable and non-viable spermatozoa. Magnetic nanoparticles have proven to be effective in the purification of boar semen by targeting nonviable spermatozoal cells (Feugang et al. 2015 IVF Reprod. Med. Genet. 3, 2), allowing potentially greater efficiency within the pork production industry. Previous research lacks data regarding the biochemical effects on offspring produced from such nanopurified semen. Here, we aim to determine whether there is a difference in protein expression between offspring produced with standard and nanopurified semen. Myoglobin (MYO) and fatty acid synthase (FAS) were chosen as the protein markers for this study because they are often studied in reference to meat quality. Myoglobin provides meat its red colour, and FAS assembles fatty acids contributing to tenderness and palatability. The results produced here will provide a baseline for further research in the meat quality and the safety of consuming meat produced with this nanopurification method. Six sows maintained on our experimental farm were inseminated with standard (CTRL) and nanopurified (NANO) boar semen, leading to the birth of viable full-term piglets. At weaning, 10 pigs (5 male and 5 female) were randomly selected from each group and allowed to grow to market weight. Samples of longissimus muscle and SC back fat were then collected from each pig and prepared for protein analyses. Western immunoblotting and immunofluorescence of tissue samples were performed using anti-MYO and anti-FAS antibodies. Images were appropriately captured and quantified (ImageJ). Data (mean ± SEM) were analysed (ANOVA/Wilcoxon) with P < 0.05 set as threshold of significance. Western immunoblotting confirmed the specificity of each antibody. Myoglobin and FAS proteins were highly detected in muscle and fat tissues, respectively, and there were no differences between groups for each protein. Compared with the CTRL group, immunofluorescence signals of MYO in fat tissues and FAS in muscle tissues were significantly reduced in NANO group pigs, irrespective of the sex. However, MYO immunofluorescence levels in fat tissues and FAS levels in all tissues were significantly reduced in females of the NANO group compared with their counterparts in the CTRL group. In conclusion, MYO and FAS proteins were confirmed as good markers for muscle and fat tissues, respectively, with similar immunofluorescence levels between CTRL and NANO groups. Current preliminary data also show that sperm nanopurification (1) may decrease FAS protein expression in muscle tissue with the possibility to affect meat quality and (2) mainly affected females in this study. Further studies are needed for confirmation of these early findings.

Ethnicity as an independent predictive factor for the results of computed tomography pulmonary angiography and ultrasonography of the lower limbs

BACKGROUND

Asians, Pacific Islanders and Maori have significantly lower rates of venous thromboembolism (VTE) compared to Europeans, but its clinic implication regarding diagnosis and prevention is unclear.

AIMS

To investigate if ethnicity affects the yield of computed tomography pulmonary angiography (CTPA) and ultrasonography of the lower limbs.

METHODS

Data previously collected for 523 patients from another study were used to analyse the effect of ethnicity on the results of CTPA; 1587 consecutive ultrasonography of lower limbs was retrospectively analysed according to ethnicity. The Wells score was retrospectively calculated to determine the pretest probability of VTE.

RESULTS

The positive rates of CTPA were 23.3% for European patients and 9.3% for non-European patients. The rate ratio was 2.50 (confidence interval [CI] 1.27-4.95). European patients were 2.5 times more likely to have a positive scan result than non-Europeans, given same pretest probability. There was a larger difference among patients with low and moderate pretest probability with a rate ratio of 4.27 (CI 1.62-11.3). The positive rates of ultrasound scans (USS) among European patients were 16.6 and 9.0% for non-European patients. Rate ratio was 1.85 (CI 1.27-4.95). The difference was also more significant amongst patients with low and moderate pretest probability. The rate ratio was 2.31 (CI 1.38-3.86) for European patients compared to non-European patients.

CONCLUSION

Given the same pretest probability according to the Wells score, European patients had significantly higher positive rates of CTPA and ultrasonography of the lower limbs than non-European patients. Further prospective studies are required to confirm our findings and establish an appropriate pretest assessment tool for non-European patients.