A Preliminary Validation of an Optimal Cutpoint in Total Number of Patient-Reported Symptoms in Head and Neck Cancer for Effective Alignment of Clinical Resources with Patients' Symptom Burden.

Background: Patients with head and neck cancer (HNC) often experience high symptom burden leading to lower quality of life (QoL). Objective: This study aims to conceptually model optimal cutpoint by examining where total number of patient-reported symptoms exceeds patients' coping capacity, leading to a decline in QoL in patients with HNC. Methods: Secondary data analysis of 105 individuals with HNC enrolled in a clinical usefulness study of the NYU Electronic Patient Visit Assessment (ePVA)©, a digital patient-reported symptom measure. Patients completed ePVA and European Organization for Research and Treatment of Cancer (EORTC©) QLQ-C30 v3.0. The total number of patient-reported symptoms was the sum of symptoms as identified by the ePVA questionnaire. Analysis of variance (ANOVA) was used to define optimal cutpoint. Results: Study participants had a mean age of 61.5, were primarily male (67.6%), and had Stage IV HNC (53.3%). The cutpoint of 10 symptoms was associated with significant decline of QoL (F= 44.8, P<.0001), dividing the population into categories of low symptom burden (< 10 symptoms) and high symptom burden (≥ 10 symptoms). Analyses of EORTC© function subscales supported the validity of 10 symptoms as the optimal cutpoint (Physical: F=28.3, P<.0001; Role: F=21.6, P<.0001; Emotional: F=9.5, P=.003; Social: F=33.1, P<.0001). Conclusions: In HNC, defining optimal cutpoints in the total number of patient-reported symptoms is feasible. Implications for Practice: Cutpoints in the total number of patient-reported symptoms may identify patients experiencing a high symptom burden from HNC. Foundational: Using optimal cutpoints of the total number of patient-reported symptoms may help effectively align clinical resources with patients' symptom burden.

Race, Ethnicity, Language, and the Treatment of Low-Risk Febrile Infants.

Importance: Febrile infants at low risk of invasive bacterial infections are unlikely to benefit from lumbar puncture, antibiotics, or hospitalization, yet these are commonly performed. It is not known if there are differences in management by race, ethnicity, or language. Objective: To investigate associations between race, ethnicity, and language and additional interventions (lumbar puncture, empirical antibiotics, and hospitalization) in well-appearing febrile infants at low risk of invasive bacterial infection. Design, Setting, and Participants: This was a multicenter retrospective cross-sectional analysis of infants receiving emergency department care between January 1, 2018, and December 31, 2019. Data were analyzed from December 2022 to July 2023. Pediatric emergency departments were determined through the Pediatric Emergency Medicine Collaborative Research Committee. Well-appearing febrile infants aged 29 to 60 days at low risk of invasive bacterial infection based on blood and urine testing were included. Data were available for 9847 infants, and 4042 were included following exclusions for ill appearance, medical history, and diagnosis of a focal infectious source. Exposures: Infant race and ethnicity (non-Hispanic Black, Hispanic, non-Hispanic White, and other race or ethnicity) and language used for medical care (English and language other than English). Main Outcomes and Measures: The primary outcome was receipt of at least 1 of lumbar puncture, empirical antibiotics, or hospitalization. We performed bivariate and multivariable logistic regression with sum contrasts for comparisons. Individual components were assessed as secondary outcomes. Results: Across 34 sites, 4042 infants (median [IQR] age, 45 [38-53] days; 1561 [44.4% of the 3516 without missing sex] female; 612 [15.1%] non-Hispanic Black, 1054 [26.1%] Hispanic, 1741 [43.1%] non-Hispanic White, and 352 [9.1%] other race or ethnicity; 3555 [88.0%] English and 463 [12.0%] language other than English) met inclusion criteria. The primary outcome occurred in 969 infants (24%). Race and ethnicity were not associated with the primary composite outcome. Compared to the grand mean, infants of families that use a language other than English had higher odds of the primary outcome (adjusted odds ratio [aOR]; 1.16; 95% CI, 1.01-1.33). In secondary analyses, Hispanic infants, compared to the grand mean, had lower odds of hospital admission (aOR, 0.76; 95% CI, 0.63-0.93). Compared to the grand mean, infants of families that use a language other than English had higher odds of hospital admission (aOR, 1.08; 95% CI, 1.08-1.46). Conclusions and Relevance: Among low-risk febrile infants, language used for medical care was associated with the use of at least 1 nonindicated intervention, but race and ethnicity were not. Secondary analyses highlight the complex intersectionality of race, ethnicity, language, and health inequity. As inequitable care may be influenced by communication barriers, new guidelines that emphasize patient-centered communication may create disparities if not implemented with specific attention to equity.

Anticipatory prescribing in community end-of-life care.

OBJECTIVES: Our work aims to critically review the use of anticipatory medicines in our inner-city hospice community population and whether our current practices are fit for purpose. METHODS: Retrospective audit of community palliative care patients at the end-of-life prescribed anticipatory medicines within a 3-month period. Anticipatory charts and case notes reviewed. Intervention included updating local guidelines, local teaching for medical and non-medical prescribers and sharing results nationally. Eighteen months later, reaudit was performed assessing impact. RESULTS: In total, 76 patients included. 75/76 (99%) were prescribed an analgesic, antiemetic, antisecretory and anxiolytic. 49/76 (64%) were administered 'as required' medications at home. Haloperidol was the favoured antiemetic (88%), costing our hospice ~£2000/month. Case note review highlighted prescribing and administration issues. Reaudit showed a reduction in prescriptions of antisecretory (by 57%) and antiemetic (by 50%), with a wider range of antiemetics (levomepromazine 47%, haloperidol 35%, cyclizine 14%, metoclopramide 3%) indicating individualised prescribing. Those without an antiemetic prescribed did not later require one dispensing. CONCLUSION: Our work challenges the orthodoxy that an analgesic, antiemetic, antisecretory and anxiolytic medication must always be included for effective anticipatory prescribing. Antiemetics may not be universally required and individualised prescribing was cost-effective and safe at a local level. Further work evaluating the impacts of altered practice on patients, caregivers, professionals and in other community settings is required.

Lung transplant survival with past and concomitant cardiac revascularization.

BACKGROUND: Coronary artery disease is common among lung transplant (LTx) candidates and has historically been viewed as a contraindication to the procedure. Survival outcomes of lung transplant recipients with concomitant coronary artery disease who had prior or perioperative revascularization remain a topic of conversation. METHODS: A retrospective analysis of all single and double lung transplant patients from Feb, 2012 to Aug, 2021 at a single center was performed (n = 880). Patients were split into 4 groups: (1) those who received a preoperative percutaneous coronary intervention, (2) those who received preoperative coronary artery bypass grafting, (3) those who received coronary artery bypass grafting during transplantation, and (4) those who had lung transplantation without revascularization. Groups were compared for demographics, surgical procedure, and survival outcomes using STATA Inc. A p value< 0.05 was considered significant. RESULTS: Most patients receiving LTx were male and white. Pump type (p = 0.810), total ischemic time (p = 0.994), warm ischemic time (p = 0.479), length of stay (p = 0.751), and lung allocation score (p = 0.332) were not significantly different between the four groups. The no revascularization group was younger than the other groups (p<0.01). The diagnosis of Idiopathic Pulmonary Fibrosis was predominant in all groups except the no revascularization group. The pre-coronary artery bypass grafting group had a higher portion of single LTx procedures (p = 0.014). Kaplan-Meier analysis showed no significantly different survival rates after post-LTx between the groups (p = 0.471). Cox Regression analysis showed diagnosis significantly impacted survival rates (p 0.009). CONCLUSIONS: Preoperative or intraoperative revascularization did not affect survival outcomes in lung transplant patients. Selected patients with coronary artery disease may benefit when intervened during lung transplant procedures.

Anaplerotic nutrient stress drives synergy of angiogenesis inhibitors with therapeutics targeting tumor metabolism.

Tumor angiogenesis is a cancer hallmark, and its therapeutic inhibition has provided meaningful, albeit limited, clinical benefit. While anti-angiogenesis inhibitors deprive the tumor of oxygen and essential nutrients, cancer cells activate metabolic adaptations to diminish therapeutic response. Despite these adaptations, angiogenesis inhibition incurs extensive metabolic stress, prompting us to consider such metabolic stress as an induced vulnerability to therapies targeting cancer metabolism. Metabolomic profiling of angiogenesis-inhibited intracranial xenografts showed universal decrease in tricarboxylic acid cycle intermediates, corroborating a state of anaplerotic nutrient deficit or stress. Accordingly, we show strong synergy between angiogenesis inhibitors (Avastin, Tivozanib) and inhibitors of glycolysis or oxidative phosphorylation through exacerbation of anaplerotic nutrient stress in intracranial orthotopic xenografted gliomas. Our findings were recapitulated in GBM xenografts that do not have genetically predisposed metabolic vulnerabilities at baseline. Thus, our findings cement the central importance of the tricarboxylic acid cycle as the nexus of metabolic vulnerabilities and suggest clinical path hypothesis combining angiogenesis inhibitors with pharmacological cancer interventions targeting tumor metabolism for GBM tumors.

Role of transoral robotic surgery in surgical treatment of early-stage supraglottic larynx carcinoma.

BACKGROUND: There are several options for primary surgical treatment of early-stage supraglottic squamous cell carcinoma (SCC), including transoral robotic surgery (TORS). The purpose of this study was to compare outcomes of TORS to open partial laryngectomy and transoral laser microsurgery (TLM). METHODS: Patients with clinical classification T1-2 supraglottic SCC diagnosed 2010-2019, treated with TORS, open partial laryngectomy, or TLM in the National Cancer Database were selected. RESULTS: One thousand six hundred three patients were included: 17% TORS, 26.5% TLM, 56.5% open. TORS patients had the lowest rates of adjuvant treatment (28.4% vs. TLM: 45.0%, open: 38.5%, p < 0.001), and lower positive margin rates than TLM (16.9% vs. 30.5%, p < 0.001). Thirty-day and ninety-day post-operative mortality did not differ between the approaches. Five-year survival was higher following TORS compared to open surgery (77.8% vs. 66.1%, p = 0.01); this difference persisted following matched-pair analysis. CONCLUSIONS: TORS may be a safe and effective surgical approach for early-stage supraglottic SCC in appropriate patients.

Characteristics of Health Care Financial Assistance Programs Serving the Most Populous U.S. Counties.

County-based health care financial assistance programs offer improved access to health care for indigent populations by reducing or eliminating costs to receive care. We examined health care financial assistance programs serving the 10 most populous U.S. counties. We found that the percent enrollment in a county's program is strongly correlated with the percent uninsured (r=.86) and the percent undocumented (r=.83), and moderately correlated with the percent indigent (r=.43) in a county, suggesting the importance of health care financial assistance programs for these groups. Furthermore, the typical county-based health care financial assistance program covers the same income range (0-138% federal poverty level) and offers similar benefits (including coverage of emergency care and inpatient care) as Medicaid. Counseling services are frequently available to assist applicants. These characteristics allow them to serve as an alternative source of health care funding to those who are ineligible for Medicaid coverage.

Prodrugs of a 1-Hydroxy-2-oxopiperidin-3-yl Phosphonate Enolase Inhibitor for the Treatment of ENO1-Deleted Cancers.

Cancers harboring homozygous deletion of the glycolytic enzyme enolase 1 (ENO1) are selectively vulnerable to inhibition of the paralogous isoform, enolase 2 (ENO2). A previous work described the sustained tumor regression activities of a substrate-competitive phosphonate inhibitor of ENO2, 1-hydroxy-2-oxopiperidin-3-yl phosphonate (HEX) (5), and its bis-pivaloyoxymethyl prodrug, POMHEX (6), in an ENO1-deleted intracranial orthotopic xenograft model of glioblastoma [Nature Metabolism 2020, 2, 1423-1426]. Due to poor pharmacokinetics of bis-ester prodrugs, this study was undertaken to identify potential non-esterase prodrugs for further development. Whereas phosphonoamidate esters were efficiently bioactivated in ENO1-deleted glioma cells, McGuigan prodrugs were not. Other strategies, including cycloSal and lipid prodrugs of 5, exhibited low micromolar IC50 values in ENO1-deleted glioma cells and improved stability in human serum over 6. The activity of select prodrugs was also probed using the NCI-60 cell line screen, supporting its use to examine the relationship between prodrugs and cell line-dependent bioactivation.

Invasive Group A Streptococcal Penicillin Binding Protein 2× Variants Associated with Reduced Susceptibility to ß-Lactam Antibiotics in the United States, 2015-2021.

All known group A streptococci [GAS] are susceptible to ß-lactam antibiotics. We recently identified an invasive GAS (iGAS) variant (emm43.4/PBP2x-T553K) with unusually high minimum inhibitory concentrations (MICs) for ampicillin and amoxicillin, although clinically susceptible to ß-lactams. We aimed to quantitate PBP2x variants, small changes in ß-lactam MICs, and lineages within contemporary population-based iGAS. PBP2x substitutions were comprehensively identified among 13,727 iGAS recovered during 2015-2021, in the USA. Isolates were subjected to antimicrobial susceptibility testing employing low range agar diffusion and PBP2x variants were subjected to phylogenetic analyses. Fifty-five variants were defined based upon substitutions within an assigned PBP2x transpeptidase domain. Twenty-nine of these variants, representing 338/13,727 (2.5%) isolates and 16 emm types, exhibited slightly elevated ß-lactam MICs, none of which were above clinical breakpoints. The emm43.4/PBP2x-T553K variant, comprised of two isolates, displayed the most significant phenotype (ampicillin MIC 0.25 µg/ml) and harbored missense mutations within 3 non-PBP genes with known involvement in antibiotic efflux, membrane insertion of PBP2x, and peptidoglycan remodeling. The proportion of all PBP2x variants with elevated MICs remained stable throughout 2015-2021 (<3.0%). The predominant lineage (emm4/PBP2x-M593T/ermT) was resistant to macrolides/lincosamides and comprised 129/340 (37.9%) of isolates with elevated ß-lactam MICs. Continuing ß-lactam selective pressure is likely to have selected PBP2x variants that had escaped scrutiny due to MICs that remain below clinical cutoffs. Higher MICs exhibited by emm43.4/PBP2x-T553K are probably rare due to the requirement of additional mutations. Although elevated ß-lactam MICs remain uncommon, emm43.4/PBP2x-T553K and emm4/PBP2x-M593T/ermT lineages indicate that antibiotic stewardship and strain monitoring is necessary.

Invasive Pneumococcal Disease Clusters Disproportionally Impact Persons Experiencing Homelessness, Injecting Drug Users, and the Western United States.

BACKGROUND: Invasive pneumococcal disease (IPD) isolates forming genomic clusters can reflect rapid disease transmission between vulnerable individuals. METHODS: We performed whole genome sequencing of 2820 IPD isolates recovered during 2019 through Centers for Disease Control and Prevention's Active Bacterial Core surveillance to provide strain information (serotypes, resistance, genotypes), and 2778 of these genomes were analyzed to detect highly related genomic clusters. RESULTS: Isolates from persons experiencing homelessness (PEH) were more often within genomic clusters than those from persons not experiencing homelessness (PNEH) (105/198 [53.0%] vs 592/2551 [23.2%]; P < .001). The 4 western sites accounted for 33.4% (929/2778) of isolates subjected to cluster analysis yet accounted for 48.7% (343/705) of clustering isolates (P < .001) and 75.8% (150/198) of isolates recovered from PEH (P < .001). Serotypes most frequent among PEH were (in rank order) 12F, 4, 3, 9N, 8, 20, and 22F, all of which were among the 10 serotypes exhibiting the highest proportions of clustering isolates among all cases. These serotypes accounted for 44.9% (1265/2820) of all IPD cases and are included within available vaccines. CONCLUSIONS: We identified serotype-specific and geographic differences in IPD transmission. We show the vulnerability of PEH within different regions to rapidly spreading IPD transmission networks representing several pneumococcal serotypes included in available vaccines.

Including Surgical Resection in the Multimodal Management of Very Locally Advanced Sinonasal Cancer.

OBJECTIVE: Sinonasal cancer often presents as locoregionally advanced disease. National guidelines recommend management of stage T4b tumors with systemic therapy and radiotherapy, but recent studies suggest that including surgical resection in the multimodal treatment of these tumors may improve local control and survival. We queried the National Cancer Database to examine patterns of care and outcomes in T4b sinonasal squamous cell carcinoma (SCC). STUDY DESIGN: Prospectively gathered data. SETTING: National Cancer Database. METHODS: Patients with T4b N0-3 M0 sinonasal squamous cell carcinoma diagnosed in 2004 to 2016 were stratified between those who received chemoradiotherapy and those who underwent surgical resection with neoadjuvant or adjuvant treatment. The overall survival of each cohort was assessed via Kaplan-Meier analysis and Cox proportional hazard models, with repeat analysis after reweighting of data via inverse probability of treatment weighting. RESULTS: Among 805 patients included in analysis, 2-year overall survival for patients undergoing surgical resection was 60.8% (95% CI, 56.1%-65.9%), while for patients undergoing chemoradiotherapy it was 46.7% (95% CI, 41.9%-52.0%). On Cox regression analysis, the inclusion of surgery in management was associated with improved survival in univariate analysis (hazard ratio [HR], 0.723 [95% CI, 0.606-0.862]; P < .001) and multivariate analysis (HR, 0.739 [95% CI, 0.618-0.885]; P = .001). Results with reweighted data were consistent in univariate analysis (HR, 0.765 [95% CI, 0.636-0.920]; P = .004]). CONCLUSION: Surgical treatment with neoadjuvant or adjuvant treatment for stage T4b sinonasal SCC was associated with promising survival outcomes, suggesting a role for incorporating surgery in treatment of select T4b SCC, particularly when removal of all macroscopic disease is feasible.

Nasopharyngeal Carriage of Streptococcus pneumoniae Among Young Children in Haiti Before Pneumococcal Conjugate Vaccine Introduction.

BACKGROUND: Streptococcus pneumoniae, or pneumococcus, is a leading cause of morbidity and mortality in children worldwide. Pneumococcal conjugate vaccines (PCV) reduce carriage in the nasopharynx, preventing disease. We conducted a pneumococcal carriage study to estimate the prevalence of pneumococcal colonization, identify risk factors for colonization, and describe antimicrobial susceptibility patterns among pneumococci colonizing young children in Port-au-Prince, Haiti, before introduction of 13-valent PCV (PCV13). METHODS: We conducted a cross-sectional study of children aged 6-24 months at an immunization clinic in Port-au-Prince between September 2015 and January 2016. Consenting parents were interviewed about factors associated with pneumococcal carriage; nasopharyngeal swabs were collected from each child and cultured for pneumococcus after broth enrichment. Pneumococcal isolates were serotyped and underwent antimicrobial susceptibility testing. We compared frequency of demographic, clinical, and environmental factors among pneumococcus-colonized children (carriers) to those who were not colonized (noncarriers) using unadjusted bivariate analysis and multivariate logistic regression. RESULTS: Pneumococcus was isolated from 308 of the 685 (45.0%) children enrolled. Overall, 157 isolates (50.8%) were PCV13 vaccine-type serotypes; most common were 6A (13.3%), 19F (12.6%), 6B (9.7%), and 23F (6.1%). Vaccine-type isolates were significantly more likely to be nonsusceptible to ≥1 antimicrobial (63.1% vs 45.4%, P = .002). On bivariate analysis, carriers were significantly more likely than noncarriers to live in a household without electricity or running water, to share a bedroom with ≥3 people, to have a mother or father who did not complete secondary education, and to have respiratory symptoms in the 24 hours before enrollment (P < .05 for all comparisons). On multivariable analysis, completion of the pentavalent vaccination series (targeting diphtheria, pertussis, tetanus, hepatitis B, and Haemophilus influenzae type b) remained significantly more common among noncarriers. CONCLUSIONS: Nearly a quarter of healthy children surveyed in Haiti were colonized with vaccine-type pneumococcal serotypes. This baseline carriage study will enable estimation of vaccine impact following nationwide introduction of PCV13.

Homozygous MTAP deletion in primary human glioblastoma is not associated with elevation of methylthioadenosine.

Homozygous deletion of methylthioadenosine phosphorylase (MTAP) in cancers such as glioblastoma represents a potentially targetable vulnerability. Homozygous MTAP-deleted cell lines in culture show elevation of MTAP's substrate metabolite, methylthioadenosine (MTA). High levels of MTA inhibit protein arginine methyltransferase 5 (PRMT5), which sensitizes MTAP-deleted cells to PRMT5 and methionine adenosyltransferase 2A (MAT2A) inhibition. While this concept has been extensively corroborated in vitro, the clinical relevance relies on exhibiting significant MTA accumulation in human glioblastoma. In this work, using comprehensive metabolomic profiling, we show that MTA secreted by MTAP-deleted cells in vitro results in high levels of extracellular MTA. We further demonstrate that homozygous MTAP-deleted primary glioblastoma tumors do not significantly accumulate MTA in vivo due to metabolism of MTA by MTAP-expressing stroma. These findings highlight metabolic discrepancies between in vitro models and primary human tumors that must be considered when developing strategies for precision therapies targeting glioblastoma with homozygous MTAP deletion.

Graves' disease patients with iron deficiency anemia: serologic evidence of co-existent autoimmune gastritis.

BACKGROUND: Graves' disease (GD) has been associated with iron deficiency anemia (IDA). Atrophic gastritis leads to IDA and has been associated with autoimmune thyroid disease. This study prospectively determined the prevalence of atrophic gastritis markers and the relationship between these markers and markers of IDA in GD subjects. METHODS: Newly diagnosed GD patients (90) and controls (41) were studied. Of the newly diagnosed GD patients, 65 were consecutively enrolled and identified with GD irrespective of anemia, 25 had GD and IDA. Thyroid function, hematologic indices, and atrophic gastritis markers [parietal-cell antibodies (PCab), Helicobacter pylori antibodies (H. pylori ab), mean serum gastrin levels] were examined. RESULTS: GD patients presenting with IDA were twice as likely (64% vs. 32%, P=0.049) to harbor PCabs when compared to all other GD subjects. Unselected GD subjects (n=65) had significantly higher PCab (37% vs. 7%, P<0.001) compared to controls. Gastrin levels were significantly elevated in all GD subjects compared to controls (105 vs. 39 pg/ml, P<0.0001). This difference was magnified in PCab+ subjects (202 vs. 64 pg/ml, P=0.003). In all GD subjects, PCabs were associated with increased gastrin levels (202 vs. 75 pg/ml, P=0.0004) and lower ferritin levels (52 vs. 95, P=0.05). In GD anemic subjects, PCabs were associated with lower mean corpuscular volume (75 vs. 81, P=0.001). Gastrin levels correlated inversely with ferritin levels in all GD subjects and positively with TIBC in GD anemic subjects. CONCLUSIONS: A significant subset of patients presenting with GD may suffer from IDA due to concurrent autoimmune atrophic gastritis.

Children's hospital quality ratings: where are we and can we do better?

OBJECTIVE: Hospital quality ratings are intended to guide patients and payers to the highest quality hospitals. Their success in achieving this goal has been limited by inconsistencies between ratings and questionable data collection methods. Despite these shortcomings, their popularity and importance are increasing. The purpose of this review is to identify the strengths and weaknesses of the US News and World Report (USNWR) Best Children's Hospitals Report and Leapfrog Pediatric Care Survey and discuss improvement opportunities. METHODS: A structured literature review was performed analyzing hospital quality surveys. Previously published criteria were used to compare the USNWR Best Children's Hospitals Report and Leapfrog Pediatric Care Survey. RESULTS: This narrative review highlights the strengths and weakness of both the USNWR Best Children's Hospitals Report and the Leapfrog Pediatric Care Survey, including a letter grade comparison. CONCLUSION: Existing children's hospital rating systems are lacking. We suggest specific improvements that may better enable these reports to influence the quality of pediatric care.

Upsurge of Conjugate Vaccine Serotype 4 Invasive Pneumococcal Disease Clusters Among Adults Experiencing Homelessness in California, Colorado, and New Mexico.

After 7-valent pneumococcal conjugate vaccine introduction in the United States in 2000, invasive pneumococcal disease (IPD) due to serotype 4 greatly decreased in children and adults. Starting in 2013, serotype 4 IPD incidence increased among adults within 3 of 10 Active Bacterial Core surveillance sites. Of 325 serotype 4 cases among adults in 2010-2018, 36% were persons experiencing homelessness (PEH); incidence of serotype 4 IPD among PEH was 100-300 times higher than in the general population within these 3 areas. Genome sequencing for isolates recovered 2015-2018 (n = 246), revealed that increases in serotype 4 IPD were driven by lineages ST10172, ST244, and ST695. Within each lineage, clusters of near-identical isolates indicated close temporal relatedness. Increases in serotype 4 IPD were limited to Colorado, California, and New Mexico, with highest increases among PEH, who were at increased risk for exposure to and infections caused by these strains.