Incidence of Sustained Ventricular Tachycardia in Patients with Prolonged QTc After the Administration of Azithromycin: A Retrospective Study.

BACKGROUND: Azithromycin has been associated with abnormalities of cardiac repolarization and development of torsades de pointes. Observational data suggest that the risk of death from cardiovascular causes is increased in patients taking azithromycin. Little is known regarding the risk of ventricular arrhythmia in patients with prolongation of the corrected QT interval who receive azithromycin. OBJECTIVE: The purpose of this study was to determine the incidence of sustained ventricular tachycardia in patients with prolonged corrected QT (QTc) who subsequently received azithromycin. METHODS: We performed a retrospective cohort analysis of the incidence of sustained ventricular tachycardia in patients with prolonged QTc (greater than 450 ms) who successively received intravenous (IV) and/or oral azithromycin. Patients hospitalized in a tertiary care teaching hospital between November 2009 and June 2012 were included in the study. The primary outcome was sustained ventricular tachycardia documented in patients on telemetry. RESULTS: Of the 103 patients enrolled in the study, only one patient experienced the primary outcome (0.97 %). The event occurred 1 day after the administration of a single dose of 500 mg IV azithromycin. CONCLUSION: The risk of sustained ventricular tachycardia was 0.97 % in our cohort of patients with prolonged QTc who subsequently received azithromycin. Given the small size of this study, additional research is needed to determine the true incidence of arrhythmia in the population.

Vaccine effectiveness of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine during a pertussis outbreak in Maine.

BACKGROUND: Multiple school-associated pertussis outbreaks were reported in Maine from 2010 to 2011. These outbreaks were associated with an overall increase in pertussis cases statewide. Waning of protection in students recently vaccinated with tetanus, diphtheria, and acellular pertussis (Tdap) has been implicated in the increase in reported rates of pertussis nationally. METHODS: We conducted a retrospective cohort study to evaluate Tdap vaccine effectiveness (VE) among students aged 11-19 years in two schools reporting outbreaks in 2011. All pertussis cases reported from August through November, 2011 at the two schools were included. Vaccination history was verified using provider information, state vaccine registry data, and parental verification. Attack rates (AR) were calculated. VE and duration of protection was calculated as VE=1-(ARvaccinated/ARunvaccinated)×100% using a log binomial regression model. RESULTS: Of 416 students enrolled, 314 were included in the analyses. Twenty-nine cases collectively in Schools A and B. Tdap coverage was 65% at School A and 42% at School B before the start of the outbreak. Among students enrolled in the study, attack rates were 11.9% and 7.7% at Schools A and B, respectively. Overall VE was 68.5% (95% confidence interval (CI) 37.7-86.2). VE was 70.4% (95% CI 17.5-89.4) for School A and 65.2% (95% CI -19.2 to 89.9) for School B. VE <2 years versus ≥2 years from outbreak onset was not significantly different. CONCLUSIONS: Tdap was moderately effective in preventing disease among vaccinated students. Vaccine coverage of 65% or less was suboptimal and might contribute to outbreaks. Waning VE was not demonstrated. Increased vaccination coverage rates as well as further evaluation of the role of acellular vaccine on VE is needed.

Serogroup B Meningococcal Disease Outbreak and Carriage Evaluation at a College - Rhode Island, 2015.

On February 2, 2015, the Rhode Island Department of Health was notified of a case of meningococcal disease in a male undergraduate student at Providence College. Three days later, a second case was reported in a male undergraduate with no contact with the first student, indicating an attack rate of 44 cases per 100,000 students, nearly 500 times higher than the national incidence of 0.15 cases per 100,000 among persons aged 17-22 years (Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC, unpublished data, 2013). Both cases were caused by a rare outbreak strain of Neisseria meningitidis serogroup B (ST-9069); neither case was fatal. In response to the outbreak, potential contacts received antibiotic chemoprophylaxis, and a mass vaccination campaign with a recently licensed serogroup B meningococcal (MenB) vaccine was implemented. In collaboration with CDC, the first phase of a meningococcal carriage evaluation was undertaken.

Rare Incidence of Ventricular Tachycardia and Torsades de Pointes in Hospitalized Patients With Prolonged QT Who Later Received Levofloxacin: A Retrospective Study.

OBJECTIVE: To determine the incidence of ventricular tachycardia and ventricular fibrillation in patients with prolonged corrected QT interval (QTc) who received levofloxacin through retrospective chart review at a tertiary care teaching hospital in the United States. PATIENTS AND METHODS: We selected 1004 consecutive hospitalized patients with prolonged QTc (>450 ms) between October 9, 2009 and June 12, 2012 at our institution. Levofloxacin was administered orally and/or intravenously and adjusted to renal function in the inpatient setting. The primary outcome measure was sustained ventricular tachycardia recorded electrocardiographically. RESULTS: With a median time from the start of levofloxacin use to hospital discharge (or death) of 4 days (range, 1-94 days), only 2 patients (0.2%; 95% CI, 0.0%-0.7%) experienced the primary outcome of sustained ventricular tachycardia after the initiation of levofloxacin use. CONCLUSION: In this study, the short-term risk for sustained ventricular tachycardia in patients with a prolonged QTc who subsequently received levofloxacin was very rare. These results suggest that levofloxacin may be a safe option in patients with prolonged QTc; however, studies with longer follow-up are needed.

Stimulation of murine intestinal secretion by daily genistein injections: gender-dependent differences.

BACKGROUND/AIMS: The effect of daily injections with genistein (naturally occurring phytoestrogen) on intestinal chloride (Cl(-)) secretion was measured with Ussing chamber short circuit current (I(sc), µA/cm(2)), in C57BL/6J male and female mice, using 600 mg/kg genistein/day (600G), 300 mg/kg genistein/day (300G), 150 mg/kg genistein/day (150G) or genistein-free vehicle control (0G) for 1- or 2-weeks. METHODS AND RESULTS: Injecting with 600G elicited significant increases in basal I(sc) in females after 1-week (ñ70 µA/cm(2), n=15, p < 0.05) and in males after 2-weeks (ñ80 µA/cm(2), n=5, p < 0.05) compared to their 0G counterparts. Chloride-free ringer significantly reduced basal I(sc) by 65% in 600G males and 72% in 600G females, suggesting that Cl(-) was the major anion comprising the genistein-stimulated secretion. The forskolin-stimulated (10 µM) I(sc) was significantly inhibited by the CFTR chloride channel inhibitors, glibenclamide (500 µM) and CFTR(inh)-172 (100 µM) in 600G males and females, suggesting some contribution by genistein-dependent CFTR-mediated Cl(-) secretion. We found no associated changes in intestinal morphology, nor change in total CFTR protein with 600G. There was a 5% increase in apical/subapical ratio in 600G males compared to controls (no change in females). CONCLUSION: These data suggest that male and female mice both exhibit increased Cl- secretion with 600G, however, the mechanisms mediating this are gender-dependent.