Evaluating the population-level effects of oxycodone restrictions on prescription opioid utilization in Ontario

PURPOSE

To investigate the impact of restrictions on access to long acting oxycodone on prescription opioid use and opioid-related harms.

METHODS

Administrative health data from Ontario, Canada was used to measure differences in opioids dispensed and ED visits for opioid-related overdose, poisoning or substance use following provincial restrictions on access to publicly insured OxyContin (February 29, 2012) and OxyNeo (February 28, 2013). This study focused on the cohort of provincial drug insurance eligible people (people 65+ and select low-income populations) who were dispensed oxycodone prior to the restrictions. Difference-in-differences models with a propensity score matched comparison group of people who were dispensed non-oxycodone opioids were used to estimate the main effects.

RESULTS

In the six months following the delisting of OxyContin, MMEs per person per week for all opioids fell by an average of 7.5% in people dispensed oxycodone relative to the comparison group, and an average of 13.8% in chronic recipients of oxycodone. In the six months following the restrictions on OxyNeo, MMEs per person per week fell by an average of 3.1% in all people dispensed oxycodone, and 25.2% in chronic oxycodone recipients. The decline in oxycodone dispensing amongst chronic oxycodone recipients corresponded with an increase in dispensing of other opioid formulations, particularly hydromorphone and fentanyl. No important differences were observed for ED visits related to opioid poisoning, overdose, or substance use disorder.

CONCLUSIONS

Province-wide restrictions on access to long acting oxycodone had an impact on quantities of all opioids dispensed to chronic recipients of oxycodone, but small impacts on the full population of people dispensed oxycodone; the decline in use was partially offset by increases in use of other publicly-funded opioid formulations. This study suggests that policies limiting access to specific prescription opioids led to overall reductions in publicly-funded prescription opioid use, particularly in chronic oxycodone recipients, without immediate evidence of changes in opioid-related ED visits. This article is protected by copyright. All rights reserved.

Costimulation of γδTCR and TLR7/8 promotes Vδ2 T-cell antitumor activity by modulating mTOR pathway and APC function

Background

Gamma delta (γδ) T cells are attractive effector cells for cancer immunotherapy. Vδ2 T cells expanded by zoledronic acid (ZOL) are the most commonly used γδ T cells for adoptive cell therapy. However, adoptive transfer of the expanded Vδ2 T cells has limited clinical efficacy.

Methods

We developed a costimulation method for expansion of Vδ2 T cells in PBMCs by activating γδ T-cell receptor (γδTCR) and Toll-like receptor (TLR) 7/8 using isopentenyl pyrophosphate (IPP) and resiquimod, respectively, and tested the functional markers and antitumoral effects in vitro two-dimensional two-dimensional and three-dimensional spheroid models and in vivo models. Single-cell sequencing dataset analysis and reverse-phase protein array were employed for mechanistic studies.

Results

We find that Vδ2 T cells expanded by IPP plus resiquimod showed significantly increased cytotoxicity to tumor cells with lower programmed cell death protein 1 (PD-1) expression than Vδ2 T cells expanded by IPP or ZOL. Mechanistically, the costimulation enhanced the activation of the phosphatidylinositol 3-kinase (PI3K)–protein kinase B (PKB/Akt)–the mammalian target of rapamycin (mTOR) pathway and the TLR7/8–MyD88 pathway. Resiquimod stimulated Vδ2 T-cell expansion in both antigen presenting cell dependent and independent manners. In addition, resiquimod decreased the number of adherent inhibitory antigen-presenting cells (APCs) and suppressed the inhibitory function of APCs by decreasing PD-L1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) expression in these cells during in vitro Vδ2 T-cell expansion. Finally, we showed that human Vδ2 T cells can be expanded from PBMCs and spleen of humanized NSG mice using IPP plus resiquimod or ZOL, demonstrating that humanized mice are a promising preclinical model for studying human γδ T-cell development and function.

Conclusions

Vδ2 T cells expanded by IPP and resiquimod demonstrate improved anti-tumor function and have the potential to increase the efficacy of γδ T cell-based therapies.

310 T cell intrinsic DNA damage and repair response as a novel marker associated with clinical response to PD-1 blockade

Background

Despite the success of immune checkpoint blockade (ICB), many patients still fail to achieve durable clinical benefit. Previous studies have shown that CD8 T cells are reinvigorated by ICB. However, not all patients with this immunological response experience an effective clinical response, suggesting additional parameters may be relevant.DNA damage and repair (DDR) has been extensively studied in the context of inducing cell death of highly-proliferating tumor cells. However, whether T cell-intrinsic DDR impacts T cell differentiation and function, and how the coordination of DDR affects immunological and clinical response to proliferation-inducing ICBs have been largely unexplored. We hypothesized that the T celI-intrinsic DDR responses to proliferative and genotoxic stress might contribute to the disparity between immunological and clinical response.

Methods

To understand the impact of cell-intrinsic DDR on T cell differentiation and responses to cancer therapies, we developed a novel high-dimensional cytometry platform. This DDR-Immune platform enables simultaneous analysis of T cell differentiation state and multiple DDR pathways at single cell resolution. We then investigated immune reinvigoration and its association with DDR, in a cohort of chemotherapy-resistant hypermutated or microsatellite instability-high (MSI-H) uterine cancer patients treated with nivolumab. Peripheral blood samples were examined every 2–4 weeks after initiating anti-PD-1 treatment (N = 21).

Results

The DDR-Immune platform revealed consistent T cell subset specific patterns of DDR, as well as specific DDR pathways induced by different types of DNA damage, such as γ-irradiation (IR), UV irradiation (UV) or proliferative stress (i.e. anti-CD3/CD28 stimulation). For example, terminally differentiated effector cells had higher DNA damage accumulation and cell death. In contrast, stem cell memory (TSCM) and regulatory T cells (Treg) displayed high DDR with less cell death, suggesting better cell-intrinsic DDR against genotoxic stress for survival advantage. In hypermutated MSI-H uterine cancer patients, CD8 T cells underwent rapid pharmacodynamic proliferation 2–4 weeks after starting PD-1 blockade, which did not correlate with clinical response. Application of the DDR-Immune platform to this cohort revealed, however, that in clinical responders but not clinical non-responders, Ki67+ CD8 T cells responding to PD-1 blockade had rapid induction of DDR represented as a spike increase of phosphorylated-ATM, presumably adapting T cell ‘fitness’ in response to proliferative stress induced by PD-1 blockade.

Conclusions

Collectively, the new platform reveals previously unrecognized roles for T cell-intrinsic DDR as a novel determinant of immune responsiveness and clinical outcome to ICB and have potential application to other cancer therapies including chemotherapy and radiotherapy.

Ethics Approval

The study was approved by MSKCC Ethics Board, approval number 17–180 (NCT03241745).

[A challenge for colorectal surgeons: pathogenesis, progression and management of the secondary tumors of the ovary]

A common clinical problem encountered by colorectal surgeons is the secondary tumors of the ovary (STO), particularly in young female patients. Most STO are from the digestive tract, and the known possible metastatic mechanisms include lymphatic, hematogenous, and intraperitoneal spreading. The molecular and histopathological characteristics of STO from different sites are diverse. It is particularly important to correctly identify the origin and feature of STO, which should be clarified by combining medical history, histopathology, immunohistochemistry, molecular biology, imaging and other means. The prognosis of patients with STO is poor in general. Comprehensive therapies based on surgical resection can benefit some patients. There is no specific treatment for STO at present, but not giving up easily on these patients is the right choice that every surgeon should understand.

Predictors of one year chronic post-surgical pain trajectories following thoracic surgery

PURPOSE

Chronic post-surgical pain (CPSP) is a highly prevalent complication following thoracic surgery. This is a prospective cohort study that aims to describe the pain trajectories of patients undergoing thoracic surgery beginning preoperatively and up to 1 year after surgery METHODS: Two hundred and seventy nine patients undergoing elective thoracic surgery were enrolled. Participants filled out a preoperative questionnaire containing questions about their sociodemographic information, comorbidities as well as several psychological and pain-related statuses. They were then followed-up during their immediate postoperative period and at the three, six and 12 month time-points to track their postoperative pain, complications and pain-related outcomes. Growth mixture modeling was used to construct pain trajectories.

RESULTS

The first trajectory is characterized by 185 patients (78.1%) with mild pain intensity across the 12 month period. The second is characterized by 32 patients (7.5%) with moderate pain intensity immediately after surgery which decreases markedly by 3 months and remains low at the 12 month follow-up. The final trajectory is characterized by 20 patients (8.4%) with moderate pain intensity immediately after surgery which persists at 12 months. Patients with moderate to severe postoperative pain intensity were much more likely to develop CPSP compared to patients with mild pain intensity. Initial pain intensity levels immediately following surgery as well as levels of pain catastrophizing at baseline were predicting pain trajectory membership. None of the surgical or anesthetic-related variables were significantly associated with pain trajectory membership.

CONCLUSION

Patients who undergo thoracic surgery can have postoperative pain that follows one of the three different types of trajectories. Higher levels of immediate postoperative pain and preoperative pain catastrophizing were associated with moderately severe CPSP.

Patient-reported outcomes in those consuming medical cannabis: a prospective longitudinal observational study in chronic pain patients

PURPOSE

We investigated patients with chronic pain seeking medical cannabis. We assessed their demographics, patterns of cannabis use, and the long-term effectiveness of cannabis on their pain and functional domains.

METHODS

This observational study enrolled patients between 8 September 2015 and 31 July 2018 from community-based cannabis clinics in Ontario, Canada. In addition to collecting demographic information, the primary outcomes studied were pain intensity and pain-related interference scores assessed at baseline, three, six, and 12 months. Using validated questionnaires, we also assessed anxiety, depression, quality of life (QoL), general health symptoms, neuropathic pain, self-reported opioid consumption, and adverse events.

RESULTS

Of the 1,000 patients consented, 757 (76%) participated at one or more of the study time points. At six and 12 months, 230 (30.4%) and 104 (13.7%) of participants were followed up, respectively. Most participants were female (62%), Caucasian (91%), and sought cannabis for pain relief (88%). Time was a significant factor associated with improvement in pain intensity (P < 0.001), pain-related interference scores (P < 0.001), QoL (P < 0.001), and general health symptoms (P < 0.001). Female sex was significantly associated with worse outcomes than male sex including pain intensity (P < 0.001) and pain-related interference (P < 0.001). The proportion of individuals who reported using opioids decreased by half, from 40.8% at baseline to 23.9% at 12 months.

CONCLUSION

Despite significant challenges to collecting long-term observational data on patients who attempted a trial of cannabis products, approximately one-third of patients in the cohort remained on medical cannabis for six months. In this cohort, pain intensity and pain-related interference scores were reduced and QoL and general health symptoms scores were improved compared with baseline.

Alarmin-activated B cells accelerate atherosclerosis after myocardial infarction via plasma cell-immunoglobulin dependent mechanisms

Introduction

Myocardial infarction (MI) accelerates atherosclerosis and for years greatly increases the risk of recurrent cardiovascular events, such as stroke and MI. B cell-derived autoantibodies produced in response to MI also persist for years.

Purpose

We investigated the role of B cells in adaptive immune responses to MI.

Methods

We used an apolipoprotein-E-deficient (ApoE−/−) mouse model of MI-accelerated atherosclerosis to assess the importance of B cells using loss and gain of function approaches. In loss of function experiment, after inducing an MI we depleted B cells using an anti-CD20 antibody. Gain of function experiments involve transfers of purified MI-B cells from different donor mice, isolated one week after MI, into atherosclerotic ApoE−/− mice.

Results

Depletion of B cells in MI mice prevented immunoglobulin G accumulation in plaques and MI-induced acceleration of atherosclerosis. Adoptive transfer of wildtype MI-B cells into atherosclerotic ApoE−/− mice greatly increased IgG accumulation in plaque and accelerated atherosclerosis in recipient mice. Cytokines that promote humoral immunity were also greatly increased in B cells activated by MI. These cells formed germinal centres within the spleen where they differentiated into antibody-producing plasma cells. Transfer of MI-B cells deficient in Blimp-1, the transcriptional repressor that drives their terminal differentiation to antibody-producing plasma cells failed to accelerate atherosclerosis in recipient mice. Alarmins released from infarcted heart were responsible for activation of B cells via toll-like receptors; transfer of MI-B cells deficient in MyD88, the canonical adaptor protein for inflammatory signaling downstream of toll-like receptors, prevented acceleration of atherosclerosis in recipient mice.

Conclusion

Our data implicate early B cell activation and autoantibodies as a central cause for accelerated atherosclerosis post MI and identifies novel therapeutic strategies towards preventing recurrent cardiovascular events such as MI and stroke.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Health and Medical Research Council of Australia

Engagement with Manage My Pain mobile health application among patients at the Transitional Pain Service

Objective

Mobile health platforms have become an important component of pain self-management programs and hundreds of mobile applications are commercially available for patients to monitor pain. However, few of these applications have been developed in collaboration with healthcare professionals or have been critically evaluated. Manage My Pain is a user-driven mobile health platform developed by ManagingLife in collaboration with clinician researchers. Manage My Pain allows patients to keep a "pain record" and supports communication of this information with clinicians. The current report describes a user engagement study of Manage My Pain among patients at the Transitional Pain Service (TPS) at Toronto General Hospital, a multidisciplinary clinic for patients at high risk of developing postsurgical pain.

Methods

Patients at the TPS were encouraged to register on Manage My Pain as one component of a larger, non-randomized prospective study of treatment predictors and treatment enhancement. Uptake of the application and rates of registration, use, and retention were tracked for 90 days.

Results

Of the 196 patients who consented to the larger study, 132 (67%) also provided consent to the Manage My Pain component, indicating that they found this to be an acceptable treatment adjunct, and 119 (61%) completed registration. Of those who used the app, 67.9% and 43.2% continued to use Manage My Pain beyond 30 and 90 days, respectively. On average, users engaged with the app for 93.14 days (SD = 151.9 days) logged an average of 47.39 total records (SD = 136.1).

Conclusions

Manage My Pain was found acceptable by a majority of patients at an academic pain management program. Rates of user registration and retention were favorable compared to those reported by other applications. Further research is needed to develop strategies to retain users and maximize patient benefit.

Gene signature of antigen processing and presentation machinery predicts response to checkpoint blockade in non-small cell lung cancer (NSCLC) and melanoma

Background

Limited data exist on the role of alterations in HLA Class I antigen processing and presentation machinery in mediating response to immune checkpoint blockade (ICB).

Methods

This retrospective cohort study analyzed transcriptional profiles from pre-treatment tumor samples of 51 chemotherapy-refractory advanced non-small cell lung cancer (NSCLC) patients and two independent melanoma cohorts treated with ICB. An antigen processing machinery (APM) score was generated utilizing eight genes associated with APM (B2M, CALR, NLRC5, PSMB9, PSME1, PSME3, RFX5, and HSP90AB1). Associations were made for therapeutic response, progression-free survival (PFS) and overall survival (OS).

Results

In NSCLC, the APM score was significantly higher in responders compared with non-responders (p=0.0001). An APM score above the median value for the cohort was associated with improved PFS (HR 0.34 (0.18 to 0.64), p=0.001) and OS (HR 0.44 (0.23 to 0.83), p=0.006). The APM score was correlated with an inflammation score based on the established T-cell-inflamed resistance gene expression profile (Pearson’s r=0.58, p<0.0001). However, the APM score better predicted response to ICB relative to the inflammation score with area under a receiving operating characteristics curve of 0.84 and 0.70 for PFS and OS, respectively. In a cohort of 14 high-risk resectable stage III/IV melanoma patients treated with neoadjuvant anti-PD1 ICB, a higher APM score was associated with improved disease-free survival (HR: 0.08 (0.01 to 0.50), p=0.0065). In an additional independent melanoma cohort of 27 metastatic patients treated with ICB, a higher APM score was associated with improved OS (HR 0.29 (0.09 to 0.89), p=0.044).

Conclusion

Our data demonstrate that defects in antigen presentation may be an important feature in predicting outcomes to ICB in both lung cancer and melanoma.

Abstract IA04: Overcoming immune resistance with rationally designed combination immunotherapy

Over the past decade, blockade of the immune checkpoints CTLA-4, PD-1, and PD-L1 has been demonstrated to significantly extend survival of cancer patients across multiple tumor types, including metastatic melanoma, formally proving that immunotherapy is a viable option for the treatment of cancer. These successes have paved the way for the development of additional immune-modulatory antibodies, blocking alternative inhibitory receptors, or engaging costimulatory receptors such as the TNF receptor family member GITR. However, the clinical experience accumulated thus far with checkpoint blockade has clearly shown that only a limited fraction of patients achieve durable clinical benefit with these treatments. This highlights the need to deepen our understanding of the molecular mechanisms underlying response and resistance to immunotherapy and design more personalized and rational combinations based on these therapies. Immune-regulatory mechanisms are one of the major barriers limiting efficacy of immunotherapy. CTLA-4 blockade and GITR costimulation are two immunotherapeutic strategies known to interfere with conventional immunosuppressive regulatory T cells (Tregs). We thus investigated the effects of CTLA-4 blockade and GITR costimulation on suppressive T cells in in vivo mouse melanoma models resistant to these therapies with the aim to clarify the molecular mechanisms underlying refractoriness and provide the rationale to develop more effective therapeutic combinations. To understand the clinical relevance of these findings, we explored the same effects in cancer patients treated with CTLA-4 blockade or GITR costimulation. We found that CTLA-4 blockade, while counteracting conventional Tregs, promotes the expansion of a subset of CD4+Foxp3-T cells expressing high levels of PD-1 (4PD1hi), which constitute a new immunosuppressive T-cell population with T-follicular-helper-like features. Importantly, we observed that anti-CTLA-4 increases the frequency of circulating 4PD1hi in a dose-dependent manner. In contrast, PD-1 blockade decreases 4PD1hi in function of its clinical activity, underscoring the relevance of this cell subset as a pharmacodynamic and prognostic biomarker of checkpoint blockade. These findings indicate that optimizing checkpoint blockade doses and combination regimens so as to keep 4PD1hi in the right balance may favor a positive outcome. In mouse melanoma models of response (early tumors) and refractoriness (advanced tumors) to GITR agonism, we found that anti-GITR efficiently reduces Tregs and increases effector:Treg ratios in both curative and refractory treatment conditions. However, T-cell activation and cytotoxic functions are favored selectively in the presence of low tumor burden. Counteracting exhaustion with PD-1 blockade in combination with GITR agonism restored responsiveness of advanced tumors and CD8+ T-cell functionality. Aligned with the effects of anti-GITR in mice, we found that the agonist anti-human GITR antibody TRX518 decreases Tregs in peripheral blood and tumor to similar extents in patients treated in the first-in-human single-dose monotherapy trial (NCT01239134). However, coincident downregulation of Tregs in the peripheral blood and at the tumor site upon TRX518 was not sufficient to achieve substantial clinical responses in this population of advanced solid cancer patients. This suggests that Treg elimination from advanced tumors may not be sufficient to activate cytotoxic T-cell responses unless the T-cell exhaustion process is concurrently blocked. Based on these preclinical and clinical observations, we have started to explore anti-GITR in combination with PD-1 pathway blockade in patients with advanced solid tumors (NCT02628574). Taken as a whole, these findings illustrate the value of conventional and nonconventional immune-suppressive T cells as biomarkers of biologic and therapeutic activity of immunotherapy in melanoma and other tumor types. In addition, these results indicate that inhibition of immune-regulatory mechanisms, such as immunosuppressive T cells, may need to be associated with strategies able to positively activate T-cell responses to achieve significant clinical benefit.

Citation Format: Roberta Zappasodi, Sadna Budhu, Cynthia Sirard, Jingjing Qi, Cailian Liu, Yanyun Li, Yasin Senbabaoglu, Sasikanth Manne, Billel Gasmi, Hong Zhong, Xia Yang, Moshen Abu-Akeel, David Schaer, Alexander Huang, Walter Newman, Philip Wong, Katherine S. Panageas, Michael A. Postow, Henry Koon, Vamsidhar Velcheti, Margaret K. Callahan, Matthew D. Hellmann, E. John Wherry, Taha Merghoub, Jedd D. Wolchok. Overcoming immune resistance with rationally designed combination immunotherapy [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr IA04.

[Blepharospasm, dry eye and extractable nuclear antigen antibodies (French translation of the article)]

PURPOSE

The goal of this study is to determine a link between benign essential blepharospasm and Sjogren's syndrome by analyzing the presence of extractable nuclear antigens in this population.

METHODS

Seventy-two patients with benign essential blepharospasm (BEB) were included in this study. We eliminated patients with hemifacial spasm or blepharospasm secondary to corneal pathology. We collected the values of the Schirmer I test and the results of the anti-SSA and anti-SSB antibodies.

RESULTS

Our study included 72 patients (144 eyes) whose 62 women (86.1%). Mean age was 74.3 years±10.73. Average Schirmer I test was 3.14mm±4.00mm. Five women (8% of this female population) had positive anti-SSA and SSB antibodies. Their mean age was 65.66 years±13.24 whereas the negative antibody patients had an average age of 75.42±9.27. There was no significant difference between their Schimer I test and the Schirmer I of negative antibody population.

CONCLUSION

This study illustrates the possible association between the presence of Sjögren's syndrome and the occurrence of a BEB justifying the search for anti-SSA and anti SSB in blepharospasm patients.

Rates of COVID-19-related Outcomes in Cancer compared to non-Cancer Patients

Cancer patients are a vulnerable population postulated to be at higher risk for severe COVID-19 infection. Increased COVID-19 morbidity and mortality in cancer patients may be attributable to age, comorbidities, smoking, healthcare exposure, and cancer treatments, and partially to the cancer itself. Most studies to date have focused on hospitalized patients with severe COVID-19, thereby limiting the generalizability and interpretability of the association between cancer and COVID-19 severity. We compared outcomes of SARS-CoV-2 infection in 323 patients enrolled prior to the pandemic in a large academic biobank (n=67 cancer patients and n=256 non-cancer patients). After adjusting for demographics, smoking status, and comorbidities, a diagnosis of cancer was independently associated with higher odds of hospitalization (OR 2.16, 95% CI 1.12-4.18) and 30-day mortality (OR 5.67, CI 1.49-21.59). These associations were primarily driven by patients with active cancer. These results emphasize the critical importance of preventing SARS-CoV-2 exposure and mitigating infection in cancer patients.

Blepharospasm, dry eye and extractable nuclear antigen antibodies

PURPOSE

To study whether there is an association between benign essential blepharospasm and Sjögren's syndrome by analyzing the presence of antibodies to extractable nuclear antigens in this population.

METHODS

Seventy-two patients with benign essential blepharospasm (BEB) were included in this study. We excluded patients with hemifacial spasm or blepharospasm secondary to known corneal pathology. We recorded results of Schirmer I testing as well as levels of anti-SSA/Ro and anti-SSB/La antibodies.

RESULTS

Our study included 72 patients (144 eyes), of which 62 (86.1%) were women. The mean age was 74.3±10.73 years. The mean Schirmer I test result was 3.14±4.00mm. Five women (8% of this female population) were found to have positive anti-SSA/Ro and anti-SSB/La antibodies. Their mean age was 65.66±13.24 years, while the mean age of the antibody-negative patients was 75.42±9.27 years. There was no statistically significant difference between the Schirmer I tests of the antibody positive and negative patients.

CONCLUSION

This study demonstrates a possible association between Sjögren's syndrome and benign essential blepharospasm, justifying anti-SSA/Ro and anti-SSB/La testing in these patients.

Efficacy of a Latex Agglutination Test for Rapid Identification of Staphylococcus aureus: Collaborative Study

Fifteen laboratories completed a collaborative study comparing the efficacy of a latex agglutination kit (Aureus Test) with that of AOAC Official Method 987.09 (coagulase test for identification of Staphylococcus aureus). Each laboratory analyzed 240 strains of bacteria, including 160 isolates of S. aureus and 80 isolates of other bacteria. Upon receipt of cultures, collaborators subcultured each isolate on both tryptic soy agar (TSA) and Baird-Parker agar medium (BPA) to determine whether the growth medium has any effect on either method. For cultures grown on TSA, the latex test had sensitivity and specificity rates of 99.2 and 97.1 %, respectively, whereas the coagulase test had respective rates of 98.4 and 92.5%. For cultures able to grow on BPA, the latex test had sensitivity and specificity rates of 99.2 and 96.6%, respectively, while the coagulase test had respective rates of 98.3 and 91.3%. By using the McNemar pairwise comparison test of the 2 methods, the falsepositive and false-negative rates of the latex test were significantly lower (p &lt; 0.01) than those of the coagulase test for strains grown either on TSA or BPA. The latex agglutination test for identification of S. aureus isolated from foods has been adopted by AOAC INTERNATIONAL.