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.

Transmission of Zika Virus - Haiti, October 12, 2015-September 10, 2016.

Zika virus disease is caused by infection with a flavivirus with broad geographic distribution and is most frequently transmitted by the bite of an infected mosquito. The disease was first identified in the World Health Organization's Region of the Americas in 2015 and was followed by a surge in reported cases of congenital microcephaly in Brazil; Zika virus disease rapidly spread to the rest of the region and the Caribbean (1), including Haiti. Infection with the virus is associated with adverse fetal outcomes (1) and rare neurologic complications in adults. The magnitude of public health issues associated with Zika virus led the World Health Organization to declare the Zika virus outbreak a Public Health Emergency of International Concern on February 1, 2016 (2). Because many persons with mild Zika virus disease are asymptomatic and might not seek care, it is difficult to estimate the actual incidence of Zika virus infection. During October 12, 2015-September 10, 2016, the Haitian Ministry of Public Health and Population (Ministère de la Santé Publique et de la Population [MSPP]) detected 3,036 suspected cases of Zika virus infection in the general population, 22 suspected cases of Zika virus disease among pregnant women, 13 suspected cases of Guillain-Barré syndrome (GBS), and 29 suspected cases of Zika-associated congenital microcephaly. Nineteen (0.6%) patients with suspected Zika virus disease, residing in Ouest (10 patients), Artibonite (six), and Centre (three) administrative departments,* have been confirmed by laboratory testing, including two among pregnant women and 17 in the general population. Ongoing laboratory-enhanced surveillance to monitor Zika virus disease in Haiti is important to understanding the outbreak and ensuring effective response activities.

Prevalence and Correlates of Genital Infections Among Newly Diagnosed Human Immunodeficiency Virus-Infected Adults Entering Human Immunodeficiency Virus Care in Windhoek, Namibia.

BACKGROUND: Identifying and treating genital infections, including sexually transmitted infections (STI), among newly diagnosed human immunodeficiency virus (HIV)-infected individuals may benefit both public and individual health. We assessed prevalence of genital infections and their correlates among newly diagnosed HIV-infected individuals enrolling in HIV care services in Namibia. METHODS: Newly diagnosed HIV-infected adults entering HIV care at 2 health facilities in Windhoek, Namibia, were recruited from December 2012 to March 2014. Participants provided behavioral and clinical data including CD4+ T lymphocyte counts. Genital and blood specimens were tested for gonorrhea, Chlamydia, trichomoniasis, Mycoplasma genitalium, syphilis, bacterial vaginosis, and vulvovaginal candidiasis. RESULTS: Among 599 adults, 56% were women and 15% reported consistent use of condoms in the past 6 months. The most common infections were bacterial vaginosis (37.2%), trichomoniasis (34.6%) and Chlamydia (14.6%) in women and M. genitalium (11.4%) in men. Correlates for trichomoniasis included being female (adjusted relative risk, [aRR], 7.18; 95% confidence interval [CI], 4.07-12.65), higher education (aRR, 0.58; 95% CI, 0.38-0.89), and lower CD4 cell count (aRR, 1.61; 95% CI, 1.08-2.40). Being female (aRR, 2.39; 95% CI, 1.27-4.50), nonmarried (aRR, 2.30; (95% CI, 1.28-4.14), and having condomless sex (aRR, 2.72; 95% CI, 1.06-7.00) were independently associated with chlamydial infection. Across all infections, female (aRR, 2.31; 95% CI, 1.79-2.98), nonmarried participants (aRR, 1.29; 95% CI, 1.06-1.59), had higher risk to present with any STI, whereas pregnant women (aRR, 1.16, 95% CI 1.03-1.31) were at increased risk of any STI or reproductive tract infection.

Monitoring long-lasting insecticidal net (LLIN) durability to validate net serviceable life assumptions, in Rwanda.

BACKGROUND: To validate assumptions about the length of the distribution-replacement cycle for long-lasting insecticidal nets (LLINs) in Rwanda, the Malaria and other Parasitic Diseases Division, Rwanda Ministry of Health, used World Health Organization methods to independently confirm the three-year LLIN serviceable life span recommendation of WHO. METHODS: Approximately 3,000 coded LLINs, distributed as part of a national campaign, were monitored in six sites, by means of six-monthly visits to selected houses. Two indicators, survivorship/attrition, a measure of the number of nets remaining, and fabric integrity, the proportion of remaining nets in either 'good', 'serviceable' or 'needs replacement' condition, based on holes in the net material, were tracked. To validate the assumption that the intervention would remain effective for three years, LLIN coverage, calculated using either survivorship, or integrity, by removing nets in the 'needs replacement' category from the survivorship total, was compared with the predicted proportion of nets remaining, derived from a net loss model, that assumes an LLIN serviceable life of three years. RESULTS: After two years, there was close agreement between estimated LLIN survivorship at all sites, 75% (range 64-84%), and the predicted proportion of nets remaining, 75%. However, when integrity was considered, observed survivorship at all sites, declined to 42% (range 10-54%). CONCLUSIONS: More than half, 58%, of the LLINs fell into the 'needs replacement' category after two years. While these nets were counted for survivorship, they were judged to be of little-to-no benefit to a user. Therefore, when integrity was taken into account, survivorship was significantly lower than predicted, suggesting that net serviceable life was actually closer to two, rather than three years, and, by extension, that the impact of the intervention during year three of the LLIN distribution-replacement cycle could be well below that seen in years one and two.

Diversity of rotavirus strains circulating in Haiti before and after introduction of monovalent vaccine.

Background: Haiti introduced a monovalent human group A rotavirus (RVA) vaccine (Rotarix) into its routine infant immunization program in April 2014. The goal of the surveillance program was to characterize RVA strains circulating in Haiti before and after RVA vaccine introduction. Methods: Stool samples were collected from children <5 years old presenting with acute gastroenteritis at 16 hospitals in Haiti. RVA antigen enzyme immunoassay (EIA) testing was performed, and G and P genotypes were determined for positive specimens. In this study, genotype data for samples collected from May 2012 through April 2014 (the pre-vaccine introduction era) and May 2014 through July 2019 (post-vaccine introduction era) were analyzed. Results: A total of 809 specimens were tested by the Centers for Disease Control and Prevention. During the pre-vaccine introduction era (May 2012 through April 2014), G12P[8] was the predominant genotype, detected in 88-94% of specimens. There was a high prevalence of the equine-like G3P[8] genotype among Haitian children with RVA after vaccine introduction. Conclusions: The predominance of equine-like G3P[8] in three of five RVA seasons post-vaccine introduction suggests possible vaccine-specific selection pressure in Haiti. These temporal variations in RVA genotype predominance will require continued monitoring in Haiti as the vaccination program continues.

MYCN amplification levels in primary retinoblastoma tumors analyzed by Multiple Ligation-dependent Probe Amplification.

Background: Retinoblastoma (Rb) is a childhood tumor of the developing retina where predisposition is caused by RB1 pathogenic variants. MYCN amplification (MYCNA) has been implicated in around 2% of sporadic unilateral Rb tumors with no detectable RB1 variants. We audited data from tumors collected between 1993 and 2019 to determine if this is the case for patients treated at Barts Health NHS Trust, and how often it occurred alongside RB1 variants. Materials and methods: Screening for MYCNA was carried out by Multiple Ligation Probe Analysis of tumor and blood samples collected for RB1 genetic screening. The cohort consisted of 149 tumors, of which 114 had matched blood samples. Results: 10/149 (6.7%) tumors were positive for MYCNA in a population containing a disproportionate number of cases negative for RB1 pathogenic variants. Of 65 unbiased tumors collected from 2014 to 2019, 2 (3.1%) had MYCNA. All MYCNA samples were from sporadic, unilateral patients and 3/10 (30%) had RB1 pathogenic variants. MYCNA was not detected in any blood sample. No MYCNA tumor had 6p gain which is usually a common alteration in Rbs. Conclusions:MYCNA occurs in a small fraction of Rbs and can occur in the presence of pathogenic RB1 variants. However, where it occurs alongside RB1 alterations, the age of onset appears to be later. MYCNA has yet to be seen as a heritable change. In sporadic cases with early diagnosis, Rbs with no RB1 pathogenic variant identified should be tested for MYCNA. Conversely, tumors with MYCNA should still be screened for RB1 pathogenic variants.

Impact of Monovalent Rotavirus Vaccine on Rotavirus Hospitalizations among Children Younger Than 5 Years of Age in the Ouest and Artibonite Departments, Haiti, 2013 to 2019.

Rotavirus is responsible for 26% of diarrheal deaths in Latin America and the Caribbean. Haiti introduced the monovalent rotavirus vaccine in April 2014. The objective of this analysis is to describe the impact of the rotavirus vaccine on hospitalizations among Haitian children younger than 5 years old during the first 5 years after introduction. This analysis includes all children with diarrhea who were enrolled as part of a sentinel surveillance system at two hospitals from May 2013 to April 2019. We compare the proportion of rotavirus-positive specimens in each post-vaccine introduction year to the pre-vaccine period. To account for the potential dilution of the proportion of rotavirus-positive specimens from a waning cholera outbreak, we also analyzed annual trends in the absolute number of positive stools, fit a two-component finite-mixture model to the negative specimens, and fit a negative binomial time series model to the pre-vaccine rotavirus-positive specimens to predict the number of rotavirus diarrhea hospital admissions in the absence of rotavirus vaccination. The overall percentage of rotavirus-positive specimens declined by 22% the first year after introduction, increased by 17% the second year, and declined by 33% to 50% the subsequent 3 years. All sensitivity analyses confirmed an overall decline. We observed a clear annual rotavirus seasonality before and after vaccine introduction, with the greatest activity in December through April, and a biennial pattern, with high sharp peaks and flatter longer periods of increased rotavirus activity in alternating years, consistent with suboptimal vaccination coverage. Overall, our study shows evidence that the introduction of the rotavirus vaccine reduced the burden of severe rotavirus diarrhea.

Effectiveness of monovalent rotavirus vaccine against hospitalizations due to all rotavirus and equine-like G3P[8] genotypes in Haiti 2014-2019.

BACKGROUND: Rotavirus vaccines are effective in preventing severe rotavirus. Haiti introduced 2-dose monovalent (G1P[8]) rotavirus vaccine recommended for infants at 6 and 10 weeks of age in 2014. We calculated the effectiveness of rotavirus vaccine against hospitalization for acute gastroenteritis in Haiti. METHODS: We enrolled children 6-59 months old admitted May 2014-September 2019 for acute watery diarrhea at any sentinel surveillance hospital. Stool was tested for rotavirus using enzyme immunoassay (EIA) and genotyped with multiplex one-step RT-PCR assay and Sanger sequencing for stratification by genotype. We used a case-negative design where cases were children positive for rotavirus and controls were negative for rotavirus. Only children eligible for vaccination were included and a child was considered vaccinated if vaccine was given ≥ 14 days before enrollment. We used unconditional logistic regression to calculate odds ratios and calculated 2-dose and 1-dose vaccine effectiveness (VE) as (1 - odds ratio) * 100. RESULTS: We included 129 (19%) positive cases and 543 (81%) negative controls. Among cases, 77 (60%) were positive for equine-like G3P[8]. Two doses of rotavirus vaccine were 66% (95% CI: 44, 80) effective against hospitalizations due to any strain of rotavirus and 64% (95% CI: 33, 81) effective against hospitalizations due to the equine-like G3P[8] genotype. CONCLUSIONS: These findings are comparable to other countries in the Americas region. To the best of our knowledge, this is the first VE estimate both against the equine-like G3P[8] genotype and from a Caribbean country. Overall, these results support rotavirus vaccine use and demonstrate the importance of complete vaccination.

Chlorhexidine maternal-vaginal and neonate body wipes in sepsis and vertical transmission of pathogenic bacteria in South Africa: a randomised, controlled trial.

BACKGROUND: About 500,000 sepsis-related deaths per year arise in the first 3 days of life. On the basis of results from non-randomised studies, use of vaginal chlorhexidine wipes during labour has been proposed as an intervention for the prevention of early-onset neonatal sepsis in developing countries. We therefore assessed the efficacy of chlorhexidine in early-onset neonatal sepsis and vertical transmission of group B streptococcus. METHODS: In a trial in Soweto, South Africa, 8011 women (aged 12-51 years) were randomly assigned in a 1:1 ratio to chlorhexidine vaginal wipes or external genitalia water wipes during active labour, and their 8129 newborn babies were assigned to full-body (intervention group) or foot (control group) washes with chlorhexidine at birth, respectively. In a subset of mothers (n=5144), we gathered maternal lower vaginal swabs and neonatal skin swabs after delivery to assess colonisation with potentially pathogenic bacteria. Primary outcomes were neonatal sepsis in the first 3 days of life and vertical transmission of group B streptococcus. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00136370. FINDINGS: Rates of neonatal sepsis did not differ between the groups (chlorhexidine 141 [3%] of 4072 vs control 148 [4%] of 4057; p=0.6518). Rates of colonisation with group B streptococcus in newborn babies born to mothers in the chlorhexidine (217 [54%] of 401) and control groups (234 [55%] of 429] did not differ (efficacy -0.05%, 95% CI -9.5 to 7.9). INTERPRETATION: Because chlorhexidine intravaginal and neonatal wipes did not prevent neonatal sepsis or the vertical acquisition of potentially pathogenic bacteria among neonates, we need other interventions to reduce childhood mortality. FUNDING: US Agency for International Development, National Vaccine Program Office and Centers for Disease Control's Antimicrobial Resistance Working Group, and Bill & Melinda Gates Foundation.

Oral cholera vaccination coverage after the first global stockpile deployment in Haiti, 2014.

INTRODUCTION: In 2014, an oral cholera vaccine (OCV) campaign targeting 185,314 persons aged ≥1 years was conducted in 3 departments via fixed post and door-to-door strategies. This was the first use of the global OCV stockpile in Haiti. METHODS: We conducted a multi-stage cluster survey to assess departmental OCV coverage. Target population estimates were projected from the 2003 Haiti population census with adjustments for population growth and estimated proportion of pregnant women. In the three departments, we sampled 30/106 enumeration areas (EAs) in Artibonite, 30/244 EAs in Centre, and 20/29 EAs in Ouest; 20 households were systematically sampled in each EA. Household and individual interviews using a standard questionnaire were conducted in each selected household; data on OCV receipt were obtained from vaccination card or verbal report. We calculated OCV campaign coverage estimates and 95% confidence intervals (CIs) accounting for survey design. RESULTS: Overall two-dose OCV coverage was 70% (95% CI: 60, 79), 63% (95% CI: 55, 71), and 44% (95% CI: 35, 53) in Artibonite, Centre, and Ouest, respectively. Two-dose coverage was higher in the 1-4 years age group than among those ≥ 15 years in Artibonite (difference: 11%; 95% CI: 5%, 17%) and Ouest (difference: 12%; 95% CI: 3, 20). A higher percentage of children aged 5-14 years received both recommended doses than did those ≥ 15 years (Artibonite: 14% (95% CI: 8%, 19%) difference; Centre: 11% difference (95% CI: 5%, 17%); Ouest: 10% difference (95% CI: 2%, 17%). The most common reason for not receiving any OCV dose was being absent during the campaign or not having heard about vaccination activities. CONCLUSIONS: While coverage estimates in Artibonite and Centre were comparable with other OCV campaigns in Haiti and elsewhere, inadequate social mobilization and outdated population estimates might have contributed to lower coverage in Ouest.

Detection and reporting of RB1 promoter hypermethylation in diagnostic screening.

BACKGROUND: RB1 gene screening aids clinical management and genetic counselling in retinoblastoma families. Here we present epigenetic changes identified during routine molecular RB1 screening of tumor and blood samples. Complications in interpreting RB1 methylation are discussed. MATERIALS AND METHODS: Screening for RB1 promoter hypermethylation was carried out by Methylation Specific PCR (MS-PCR) after bisulphite modification of DNA. The cohort consisted of 315 tumors, and 204 blood samples, from 497 retinoblastoma patients (22 patients had both blood and tumor screened). RESULTS: 11.4% of retinoblastoma tumors had promoter hypermethylation. It was not routinely detected in blood samples, or in tumors with two other oncogenic RB1 changes. One blood sample had promoter hypermethylation due to an X;13 translocation. One tumor had low level methylation as well as two other oncogenic changes. Histopathological analysis of a small subset of age-matched tumors was similar regardless of promoter hypermethylation status. CONCLUSIONS: Promoter hypermethylation was detected in 11.4% of the retinoblastoma tumors and should be tested for in routine RB1 screening programmes. Constitutional samples are not expected to display RB1 hypermethylation. In a small proportion of cases it may not be possible to use this somatic change in patient management.

Expansion of Vaccination Services and Strengthening Vaccine-Preventable Diseases Surveillance in Haiti, 2010-2016.

Following the 2010 earthquake, Haiti was at heightened risk for vaccine-preventable diseases (VPDs) outbreaks due to the exacerbation of long-standing gaps in the vaccination program and subsequent risk of VPD importation from other countries. Therefore, partners supported the Haitian Ministry of Health and Population to improve vaccination services and VPD surveillance. During 2010-2016, three polio, measles, and rubella vaccination campaigns were implemented, achieving a coverage > 90% among children and maintaining Haiti free of those VPDs. Furthermore, Haiti is on course to eliminate maternal and neonatal tetanus, with 70% of communes achieving tetanus vaccine two-dose coverage > 80% among women of childbearing age. In addition, the vaccine cold chain storage capacity increased by 91% at the central level and 285% at the department level, enabling the introduction of three new vaccines (pentavalent, rotavirus, and pneumococcal conjugate vaccines) that could prevent an estimated 5,227 deaths annually. Haiti moved from the fourth worst performing country in the Americas in 2012 to the sixth best performing country in 2015 for adequate investigation of suspected measles/rubella cases. Sentinel surveillance sites for rotavirus diarrhea and meningococcal meningitis were established to estimate baseline rates of those diseases prior to vaccine introduction and to evaluate the impact of vaccination in the future. In conclusion, Haiti significantly improved vaccination services and VPD surveillance. However, high dependence on external funding and competing vaccination program priorities are potential threats to sustaining the improvements achieved thus far. Political commitment and favorable economic and legal environments are needed to maintain these gains.

Strengthening National Disease Surveillance and Response-Haiti, 2010-2015.

Haiti's health system has faced many challenges over the years, with competing health priorities in the context of chronic financial and human resource limitations. As a result, the existing notifiable disease surveillance system was unable to provide the most basic epidemiologic data for public health decision-making and action. In the wake of the January 2010 earthquake, the Haitian Ministry of Public Health and Population collaborated with the U.S. Centers for Disease Control and Prevention, the Pan American Health Organization, and other local and international partners to implement a functional national surveillance system. More than 7 years later, it is important to take the opportunity to reflect on progress made on surveillance and response in Haiti, including disease detection, reporting, outbreak investigation, and response. The national epidemiologic surveillance network that started with 51 sites in 2010 has been expanded to 357 sites as of December 2015. Disease outbreaks identified via the surveillance system, or other surveillance approaches, are investigated by epidemiologists trained by the Ministry of Health's Field Epidemiology Training Program. Other related surveillance modules have been developed on the same model and electronic platform, allowing the country to document the impact of interventions, track progress, and monitor health problems. Sustainability remains the greatest challenge since most of the funding for surveillance come from external sources.

The Health Impact of Rabies in Haiti and Recent Developments on the Path Toward Elimination, 2010-2015.

Haiti, a Caribbean country of 10.5 million people, is estimated to have the highest burden of canine-mediated human rabies deaths in the Western Hemisphere, and one of the highest rates of human rabies deaths in the world. Haiti is also the poorest country in the Western Hemisphere and has numerous economic and health priorities that compete for rabies-control resources. As a result, primary rabies-control actions, including canine vaccination programs, surveillance systems for human and animal rabies, and appropriate postbite treatment, have not been fully implemented at a national scale. After the 2010 earthquake that further hindered the development of public health program infrastructure and services, the U.S. Centers for Disease Control and Prevention worked with the Ministry of Public Health and Population and key health development partners (including the Pan-American Health Organization) to provide technical expertise and funding for general disease surveillance systems, laboratory capacity, and selected disease control programs; including rabies. In 2011, a cross-ministerial rabies consortium was convened with participation from multiple international rabies experts to develop a strategy for successful rabies control in Haiti. The consortium focused on seven pillars: 1) enhancement of laboratory diagnostic capacity, 2) development of comprehensive animal surveillance system, 3) development of comprehensive human rabies surveillance system, 4) educational outreach, 5) sustainable human rabies biologics supply, 6) achievement of sustained canine vaccination rates of ≥ 70%, and 7) finalization of a national rabies control strategy. From 2010 until 2015, Haiti has seen improvements in the program infrastructure for canine rabies control. The greatest improvements were seen in the area of animal rabies surveillance, in support of which an internationally recognized rabies laboratory was developed thereby leading to an 18-fold increase in the detection of rabid animals. Canine rabies vaccination practices also improved, from a 2010 level of approximately 12% to a 2015 dog population coverage level estimated to be 45%. Rabies vaccine coverage is still below the goal of 70%, however, the positive trend is encouraging. Gaps exist in the capacity to conduct national surveillance for human rabies cases and access to human rabies vaccine is lacking in many parts of the country. However, control has improved over the past 5 years as a result of the efforts of Haiti's health and agriculture sectors with assistance from multiple international organizations. Haiti is well situated to eliminate canine-mediated human rabies deaths in the near future and should serve as a great example to many developing countries struggling with similar barriers and limitations.

Acquired Resistance to the TRK Inhibitor Entrectinib in Colorectal Cancer.

UNLABELLED: Entrectinib is a first-in-class pan-TRK kinase inhibitor currently undergoing clinical testing in colorectal cancer and other tumor types. A patient with metastatic colorectal cancer harboring an LMNA-NTRK1 rearrangement displayed a remarkable response to treatment with entrectinib, which was followed by the emergence of resistance. To characterize the molecular bases of the patient's relapse, circulating tumor DNA (ctDNA) was collected longitudinally during treatment, and a tissue biopsy, obtained before entrectinib treatment, was transplanted in mice (xenopatient), which then received the same entrectinib regimen until resistance developed. Genetic profiling of ctDNA and xenopatient samples showed acquisition of two point mutations in the catalytic domain of NTRK1, p.G595R and p.G667C. Biochemical and pharmacologic analysis in multiple preclinical models confirmed that either mutation renders the TRKA kinase insensitive to entrectinib. These findings can be immediately exploited to design next-generation TRKA inhibitors. SIGNIFICANCE: We provide proof of principle that analyses of xenopatients (avatar) and liquid biopsies allow the identification of drug resistance mechanisms in parallel with clinical treatment of an individual patient. We describe for the first time that p.G595R and p.G667C TRKA mutations drive acquired resistance to entrectinib in colorectal cancers carrying NTRK1 rearrangements.

Reduction in pediatric hospitalizations for varicella-related invasive group A streptococcal infections in the varicella vaccine era.

OBJECTIVES: To assess changes in hospitalization rates for invasive group A streptococcal (IGAS) and varicella-associated IGAS (VA-IGAS) infections at a pediatric hospital over a period of 9 years, to characterize clinical features of patients with IGAS infections, and to assess frequency of macrolide-resistant IGAS isolates. Study design Medical records of all hospitalized patients with group A streptococcus isolated from a normally sterile site from 1993 to 2001 were reviewed. Data collected included demographics, clinical course, microbiologic features, outcome, and presence of streptococcal toxic shock syndrome (STSS) or necrotizing fasciitis (NF). Annual hospitalization rates for IGAS were determined. RESULTS: There were 144 patients with IGAS infections, including 11 (8%) with STSS or NF. Overall mortality rate was 2% (3/144) but 18% (2/11) among patients with STSS or NF. Preexisting varicella was present in 16% (23/144); 4 of 23 VA-IGAS cases had STSS or NF. Although there was no change in annual hospitalization rates for IGAS infections during the study period, the percentage of VA-IGAS hospitalizations decreased from 27% in the prevaccine era (1993 to 1995), to 16% during vaccine implementation (1996 to 1998) and 2% during widespread vaccine use (1999 to 2001) (linear-by-linear association, P=.001). Macrolide resistance was low in 1993 to 1995 (5%, 1/19) and 1996 to 1998 (0%, 0/42) among tested IGAS isolates and increased significantly in 1999 to 2001 (13%, 5/38) (Fisher exact, P=.035). CONCLUSIONS: A decline in pediatric varicella-related IGAS hospitalizations was temporally associated with utilization of varicella vaccine. These data reinforce the importance of universal varicella vaccination for children. Increasing macrolide resistance among IGAS isolates indicates a need for continued surveillance.

Imaging metabolism of phosphatidylinositol 4,5-bisphosphate in T-cell GM1-enriched domains containing Ras proteins.

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) and Ras proteins are involved in signalling pathways originating at the plasma membrane. The localisation and metabolism of PI(4,5)P(2) was studied in Jurkat T cells using fluorescence microscopic imaging with EGFP-tagged and antibody probes. Software was developed to objectively quantitate colocalisation and was used to show that plasma membrane PI(4,5)P(2) was enriched in lipid raft-containing patches of GM1 ganglioside, formed by crosslinking cholera toxin B-subunit (CT-B). The PI(4,5)P(2) metabolites phosphatidylinositol 3,4,5-trisphosphate and diacylglycerol appeared in plasma membrane CT-B-GM1 patches upon induction of signalling. Transferrin receptor and the CD45 tyrosine phosphatase did not colocalise with CT-B-GM1 patches, whereas the tyrosine kinase Lck, the scaffolding protein LAT, and endogenous Ras proteins did partially colocalise with CT-B-GM1 patches as did transfected EGFP-K-Ras(4B) and EGFP-H-Ras. The results demonstrate that T-cell PI(4,5)P(2) metabolism is occurring in GM1-enriched domains and that Ras proteins are present in these domains in vivo.

Quantitative electroencephalography in frontotemporal dementia with methylphenidate response: a case study.

Frontotemporal dementia is an underdiagnosed illness with predominant behavioral and executive manifestations. Historically, diagnosis has been based on a combination of clinical history, neuropsychological testing, and brain imaging. No effective treatment currently exists for this disorder. A case is presented using quantitative EEG with methylphenidate challenge correlated with SPECT. The patient underwent neuropsychological testing, a SPECT brain study, and a quantitative EEG, which was repeated after methylphenidate administration. SPECT was significant for hypoperfusion to the bilateral frontotemporal regions, with left-sided hypoperfusion greater than homologous right as demonstrated by LORETA analysis. QEEG correlated with SPECT, and demonstrated profound left greater than right bi-frontotemporal slowing, which normalized partially after methylphenidate administration. The patient has remained on methylphenidate as an outpatient, and has had significant behavioral improvement. Quantitative EEG may provide both diagnostic and therapeutic data with regard to frontotemporal dementia. Further studies of methylphenidate in this population are needed to confirm these data.