Shigella flexneri serotype 1 infections in men who have sex with men in Vancouver, Canada.

OBJECTIVES: Outbreaks of shigellosis have been documented in men who have sex with men (MSM), associated with interpersonal transmission and underlying HIV infection. We observed a rise in Shigella flexneri isolates identified in a downtown tertiary-care hospital laboratory located within the city centre community health area (CHA-1) of Vancouver, Canada. The objectives of this study were to evaluate clinical outcomes of shigellosis cases among MSM admitted to hospital and to evaluate trends in Shigella cases within Vancouver, Canada. METHODS: Adult rates of shigellosis were analysed by gender and health region, from 2005 to 2011, followed by retrospective chart review of all hospital laboratory-identified S. flexneri cases from 2008 to 2012. Serotyping and pulsed-field gel electrophoresis (PFGE) were performed on these isolates. RESULTS: Although shigellosis rates in men within CHA-1 did not change from 2005 to 2011 (range 33.4-68.5 per 100 000; P = 0.74), they were significantly higher than in other regions within the city of Vancouver (P ≤ 0.001) and the province of British Columbia (P ≤ 0.001). Shigella flexneri rates in men within CHA-1 increased significantly (range 2.3-51.4 per 100 000; P < 0.001), starting in 2008, and were higher than in other regions within Vancouver (P ≤ 0.01). Seventy-nine isolates of S. flexneri from 72 patients were identified by a single hospital laboratory. All patients were male and predominantly MSM (91.7%) and HIV-infected (86.1%), with most (92.6%) demonstrating CD4 counts ≥ 200 cells/µL. In total, 38.0% required hospitalization. Most (87.3%) had S. flexneri serotype 1 infection, with 72.9% of these representing a single PFGE pattern. CONCLUSIONS: We identified high levels of transmission of a primarily clonal strain of S. flexneri serotype 1 in our local MSM population, resulting in a substantial burden of illness and health care resource use secondary to hospital admissions.

Methicillin-resistant Staphylococcus aureus nasal carriage among injection drug users: six years later.

A survey in 2000 to detect methicillin-resistant Staphylococcus aureus (MRSA) colonization in Vancouver downtown east side injection drug users (IDUs) revealed an MRSA nasal colonization incidence of 7.4%. This is a follow-up study to determine the current prevalence of MRSA colonization and to further characterize the isolates and risk factors for colonization. In this point prevalence study of MRSA nasal carriage among IDUs, nasal swabs were cultured to detect S. aureus. Isolates were studied for their antimicrobial susceptibility patterns and the presence of mecA and Panton-Valentine leukocidin (PVL) genes and by pulsed-field gel electrophoresis (PFGE). S. aureus was isolated from 119 of 301 (39.5%) samples; three (2.5%) participants had both methicillin-sensitive S. aureus (MSSA) and MRSA, resulting in 122 isolates. Of these, 54.1% were MSSA and 45.9% were MRSA, with an overall MRSA rate of 18.6%. USA-300 (CMRSA-10) accounted for 75% of all MRSA isolates; 25% were USA-500 (CMRSA-5). None of the USA-500 isolates were positive for PVL; 41 (97.6%) USA-300 isolates contained PVL. One MSSA isolate, from an individual also carrying USA-300, was positive for PVL. The PFGE pattern of this MSSA isolate was related to that of the MRSA strain. The antibiograms of USA-300 compared to USA-500 isolates showed 100% versus 7.1% susceptibility to trimethoprim-sulfamethoxazole (TMP-SMX) and 54.8% versus 7.1% susceptibility to clindamycin. MRSA nasal colonization in this population has increased significantly within the last 6 years, with USA-300 replacing the previous strain. Most of these strains are PVL positive, and all are susceptible to TMP-SMX.

Rapid subcutaneous immunoglobulin administration every second week results in high and stable serum immunoglobulin G levels in patients with primary antibody deficiencies.

Subcutaneous immunoglobulin G (SCIG) infusions as life-long replacement therapy in patients with primary antibody deficiences (PAD) is being applied increasingly. However, only a few published pharmacokinetic studies are available for this route of administration. Therefore, the pharmacokinetics of a 16% immunoglobulin G (IgG) preparation intended for subcutaneous use were investigated in patients with common variable immunodeficiency and X-linked agammaglobulinaemia. SCIG infusions (200 mg/kg body weight) were administered to 12 adult patients every 14 days for 24 weeks (total of 144 infusions). Pharmacokinetic parameters were determined based on serum IgG trough levels and antibody levels against tetanus. The median half-life of the total serum IgG and for the tetanus antibodies was 40.6 and 23.3 days respectively. Median in vivo recovery of serum IgG and tetanus immunoglobulins were 36% and 46% respectively. Median, preinfusion serum IgG trough levels per patient were high without major variations between infusions and ranged from 7.24 to 7.86 g/l. Safety, in terms of adverse events including systemic adverse reactions and local tissue reactions at infusions sites, was monitored throughout the study. Six mild, local tissue reactions were observed during the study in one patient. No systemic adverse reactions related to the study drug were observed and no serious other adverse event occurred during the study. It is concluded that the bi-weekly SCIG therapy was well tolerated in the study and that it results in high and stable serum IgG levels, offering an alternative therapy regimen to patients suffering from PAD.

Surveillance summary of hospitalized pediatric enterovirus D68 cases in Canada, September 2014.

BACKGROUND: Enterovirus D68 (EV-D68) has been detected infrequently and has not been associated with severe disease in Canada. In the early fall of 2014, following an unusual case increase in the United States, clusters of EV-D68 among children and some adults manifesting severe symptoms were reported in Canada. OBJECTIVE: To provide an initial epidemiological summary of pediatric cases hospitalized with EV-D68 in Canada. METHODS: A time-limited surveillance pilot was conducted collecting information on pediatric cases (less than 18 years of age) hospitalized with EV-D68 between September 1 and 30, 2014. RESULTS: In total, 268 cases were reported from Ontario (n=210), Alberta (n=45), and British Columbia (n=13). Of the 268 reported cases, 64.9% (n=174) were male; the sex difference was statistically significant (p<0.01). Age was reported for 255 cases, with a mean age for males of 5.4 years and for females of 5.3 years. For cases with data available, 6.8% (18/266) were admitted to an intensive care unit. Of those where clinical illness was recorded, respiratory illness alone was present in 98.3% (227/231), neurologic illness alone was present in 0.4% (n=1), and both illnesses were present in 0.9% of cases (n=2); cases with neither respiratory nor neurologic illness were rare (n=1). Of the 90 cases with additional clinical information available, 43.3% were reported as having asthma. No deaths were reported among the 268 cases. CONCLUSION: The EV-D68 outbreak in Canada in September 2014 represents the beginning of a novel outbreak associated with severe illness in children. These findings provide the first epidemiological summary of severe cases of EV-D68 as an emergent respiratory pathogen in Canada. The continued investigation of this pathogen is necessary to build on these results and capture the full spectrum of associated illness.

Partial anomalous pulmonary venous connection to the right side of the heart.

Partial anomalous pulmonary venous connection to the right side of the heart often complicates surgery for atrial septal defects. Between 1964 and 1987, 39 patients, ranging from 2 to 52 years old, underwent repair of partial anomalous pulmonary venous connection. At least one anomalous pulmonary vein arose from the right upper lobe in 38 patients and right middle lobe in 30 patients and connected to the superior vena cava in 28 patients and the right atrium only in 11 patients. An atrial septal defect was present in 32 patients (82%). Patients who had partial anomalous pulmonary venous connection to the superior vena cava-right atrium junction, the right atrium or both were treated by septal translocation (two patients) or patch redirection of the anomalous pulmonary venous flow to the left atrium through a native atrial septal defect (eight patients) or a surgically created atrial septal defect in two patients with intact atrial septum. For partial anomalous pulmonary venous connection to the high superior vena cava (27 patients), the superior vena cava was transected and oversewn above the anomalous veins. The anomalous pulmonary venous flow was redirected through the proximal superior vena cava into the left atrium across a sinus venous atrial septum defect (22 patients) or a surgically created atrial septal defect in five patients with intact atrial septum. The atrial septal defect was coapted to the intracardiac orifice of the superior vena cava, and the distal superior vena cava was anastomosed to the right atrial appendage. One 31-year-old woman with severe pulmonary hypertension died early and was the only death in the series. A technical error early in the series resulted in one symptomatic superior vena cava obstruction. Only one patient remains in sick sinus syndrome late. All patients remain well over long follow-up (1 to 24 years). Postoperative catheterization or echocardiography has revealed no intracardiac defects, pulmonary venous obstruction, or superior vena cava obstruction (except the one technical error). Correction of partial anomalous pulmonary venous connection should be individualized according to the site of connection of the anomalous pulmonary veins and the location of the atrial defect to minimize undesirable postoperative sequelae often associated with other methods of repair.

Plasma antioxidant depletion after cardiopulmonary bypass in operations for congenital heart disease.

We describe the use of two in vitro tests to characterize plasma antioxidant capacity at the time of cardiac bypass in operations for congenital heart disease in 30 patients aged 3 days to 16 years (average 4.4 +/- 0.9 years [standard error]). Bypass and crossclamp time, circuit volume, and type of operation were recorded for each patient. First, a test of plasma radical antioxidant power measured chain breaking (secondary) antioxidant capacity of plasma to prevent oxidation of linoleic acid in vitro. Second, overall ability of plasma to prevent lipid peroxidation was assessed by a classic test of plasma inhibition of malondialdehyde formation in a beef brain homogenate. Plasma total radical antioxidant power level at baseline was 0.74 +/- 0.03 mumol/ml plasma, which decreased to 0.15 +/- 0.05 mumol/ml plasma after bypass (p < 0.001) and 0.26 +/- 0.08 mumol/ml plasma with recovery (n = 18, p < 0.001). Analysis of variance of postbypass total radical antioxidant power value showed age (p = 0.0002, r = 0.63) and bypass time (p = 0.009, r = 0.4677) to be significant factors. Pump prime volume in milliliters per kilogram and preoperative hemoglobin value were not significant factors. Beef brain malondialdehyde formation in vitro was limited 92% +/- 3% by normal plasma before operation versus 53% +/- 5% after operation (p < 0.001) and 51% +/- 5% at recovery after arrival in the pediatric intensive care unit (p < 0.001). Analysis of variance of the changes from before to after operation showed age p = 0.0015, r = 0.55) and bypass time (p = 0.033, r = 0.39) to be significant factors. Thus antioxidant capacity of plasma is significantly diminished after cardiopulmonary bypass in children. Young patient age and long duration of cardiopulmonary bypass are identified as factors that correlate positively with depletion of antioxidant capacity with bypass.

Preservation of adenosine 5'-triphosphate and mitochondrial function during hypercalcemic reperfusion using verapamil cardioplegia.

Immediate hypercalcemic reperfusion results in ventricular dysfunction and loss of high-energy stores. The purpose of this study was to evaluate the effect of verapamil cardioplegia on the preservation of myocardial energy stores, mitochondrial ultrastructure, and ventricular dysfunction in the postischemic rat heart during immediate hypercalcemic reperfusion. Rats in the control group were subjected to cardioplegia with potassium, while rats in groups 1 to 3 were subjected to the same with verapamil (0.5 mg/L). The control and group 1 rats underwent normocalcemic reperfusion and groups 2 and 3 rats underwent hypercalcemic reperfusion. Myocardial samples were analyzed for adenosine 5'-triphosphate (ATP) content and mitochondrial ultrastructural damage. Hemodynamic parameters of heart rate, aortic flow (AF), and postischemic rate of aortic pressure change (dP/dT) also were evaluated. Data were analyzed using analysis of variance. The ATP stores were preserved at greater than 100% control levels in hearts subjected to verapamil cardioplegia. There was no evidence of irreversible mitochondrial damage. Heart rate, AF, and dP/dT were significantly (p < 0.05) depressed in hearts subjected to verapamil cardioplegia. This study suggests verapamil cardioplegia preserves ATP and mitochondrial function during immediate hypercalcemic reperfusion but does not improve postischemic hemodynamics.

Current management of esophageal impactions.

We analyzed our experience at a university medical center from 1977 to 1990 to assess our success in using esophagoscopy and related treatments for removing esophageal impactions. There were 157 episodes of impaction in 150 patients, consisting of 39 pediatric and 111 adult patients. In the pediatric cases, foreign bodies were most often the cause of impaction, while adult cases were usually caused by food or bones. Esophagoscopy was performed successfully in 32 of 34 pediatric patients in which it was attempted; there was only one complication. Other forms of therapy that were infrequently tried met with variable results. Esophagoscopy was successful in removing the impaction in 104 of 109 attempts in adults. Two perforations occurred, with one resulting in death. Various other methods achieved success in the remaining patients. The data suggest that esophageal impaction can be treated successfully by endoscopy with very low morbidity and mortality.

New limit on CPT violation

A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on fifteen antiproton decay modes. The results are used to place limits on the characteristic mass scale m(X) that could be associated with CPT violation accompanied by baryon number violation.

Transfer by BMT of IgG2 deficiency involving an immunoglobulin heavy chain constant region deletion and a silent IgG2 gene.

A patient suffering from ALL who underwent allogeneic BMT developed complete IgG2 deficiency after BMT. When the donor Ig serum levels were examined, it was found that he also lacked detectable levels of IgG2. The IGHC genes were investigated and a heterozygous 50-70 kb deletion encompassing the genes coding for IgG2 (G2) and IgG4 (G4) (del G2-G4) was found in the white blood cells. The patient had IgG2 levels in the low normal range before BMT. When the patient's fibroblasts were examined to determine his original genotype, they were found to carry the same deletion haplotype, but in combination with a different G2 allele than that present in the transplanted BM cells. The combination of Ig heavy chain constant region gene alleles found in the transplant has also been inherited by a third brother also lacking IgG2. The hemizygous G2 allele present in the donated BM cells was thus 'silent' and the complete IgG2 deficiency had been transferred by the BMT.

Tolerance of sheep-goat chimeras to their component cells.

Four sheep-goat chimeras with a goat or sheep sibling having an identical genotype to one of the two component species of cells were tested for tolerance through mixed lymphocyte response (MLR) and skin grafts. None of the four chimeras showed a response to its sib in MLR and three of the four accepted sib skin grafts. This demonstrates that the chimerism exhibited by these animals was sufficient to render the chimera tolerant to antigens expressed by the sib. Two of the four sibs showed positive responses to their chimeric sibs in MLR and two did not; one negative response was expected because the chimera's lymphocytes were essentially all the same species as the sib's. Chimeric skin grafts were partially accepted by two of the four sibs, suggesting the presence of both sheep and goat cells in the skin grafts derived from the chimeras. Two of the four sibs did not accept chimeric skin grafts, possibly due to lack of compatible cells in the graft. Neither differences between an allo- and xenoresponse in MLR nor time differences in the rejection of allo- and xenografts were observed.

Partial anomalous pulmonary venous connection to the superior vena cava.

BACKGROUND: Correction of partial anomalous pulmonary venous connection to the superior vena cava (SVC) is often complicated by sinus node dysfunction and occasional pacemaker insertion. METHODS: Between 1964 and 1994 40 patients, ranging from 14 months to 52 years old, underwent an operative approach designed to minimize trauma to the sinus node and its blood supply. The SVC was transected and oversewn above the highest anomalous vein. The anomalous pulmonary veins were redirected across a sinus venosus atrial septal defect (33 patients) or a surgically created atrial septal defect (7 patients) into the left atrium. The atrial septal defect rim was coapted to the intracardiac SVC orifice in 23 patients. An intracardiac baffle was used in 17 patients. The cephalad SVC stump was anastomosed to the right atrial appendage. The origin of the pulmonary veins draining into the SVC was right upper lobe (all patients), right middle lobe (33 patients), and the entire right lung (9 patients). RESULTS: One 31-year-old woman died of severe pulmonary hypertension. An early technical error resulted in one symptomatic SVC obstruction. All patients remained well over follow-up (6 months to 30 years), without residual intracardiac defects. Sick sinus syndrome developed late in only 1 patient (2.5%). No patient has required a pacemaker. CONCLUSIONS: The very low incidence of late arrhythmias with cavoatrial reconstruction is most encouraging.

Early primary repair of tetralogy of Fallot.

Young age, low weight, and the requirement for transannular patch reconstruction of the right ventricular outflow tract (RVOT) are thought to adversely affect intracardiac repair of tetralogy of Fallot. Forty patients underwent complete repair between January, 1984, and January, 1987. Only infants with pulmonary atresia, complete atrioventricular canal, or coronary artery anomalies were shunted initially. The malalignment ventricular septal defect was closed with a Dacron patch. Infundibular resection was minimized. All atrial communications were left open. Thirty-four patients (85%) had a transannular RVOT patch, and 2 patients (5%) had a nontransannular patch. All 10 infants weighing 3.4 to 9.6 kg had a transannular RVOT patch at 7 weeks to 12 months of age. An RVOT patch was used in 26 of 30 children operated on between 1 and 6 years of age (median age, 24 months). No patient undergoing intracardiac repair died. Postoperative RVOT pullback gradients were between 0 and 35 mm Hg (mean, 18.5 mm Hg). Postoperative pulmonary artery saturation (mean, 73%) did not reveal any residual ventricular septal defect. The right ventricular/arterial pressure ratio was always less than 0.6 (mean, 0.4). All children are doing well at follow-up from two to 37 months. Serial echocardiograms reveal no residual ventricular septal defect and only 1 moderate RVOT gradient. Follow-up cardiac catheterization in 15 patients revealed no residual ventricular septal defect and RVOT gradients between 5 and 35 mm Hg. The right ventricular/left ventricular pressure ratio was always less than 0.6 (mean, 0.48). The early and late results justify continued primary repair of tetralogy of Fallot in symptomatic children, regardless of age or weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of lung decortication in symptomatic empyemas in children.

Despite appropriate antibiotics and pleural drainage, the condition of some children with empyema fails to improve. In a 5-year period, 10 children ranging in age from 2 to 16 years underwent lung decortication for a refractory, symptomatic empyema, which had developed 3 to 5 weeks after an initial pneumonic infiltrate. Responsible organisms included beta-hemolytic streptococci, Haemophilus influenzae, or Streptococcus pneumoniae in 6 children. Negative cultures were found in 4 children. The initial computed tomographic scan of the chest in 4 of 8 patients showed more than 75% limitation of lung expansion by the contents of the empyema cavity. In 4 other patients, an extensive pleural peel was seen on initial computed tomographic scan of the chest. Several studies also showed cystic lesions in the collapsed lung. Multiple computed tomographic scans in 3 patients confirmed the lack of clinical and chest roentgenographic improvement with conservative therapy. At decortication in each, the visceral and parietal pleural peel was completely removed, freeing the trapped lung. Two patients also had a concomitant lobectomy for a necrotic right upper lobe (1 patient) and left lower lobe (1). Clinical improvement was marked, with return of temperature, white blood cell count, and appetite to normal. Postoperative morbidity was minimal. Analysis of these patients in whom traditional conservative therapy failed suggested that the initial management during the early exudative phase was often delayed and was not aggressive enough from the standpoint of pleural drainage.(ABSTRACT TRUNCATED AT 250 WORDS)

Stage I palliation of hypoplastic left heart syndrome: the importance of neoaorta construction.

After Norwood's initial report of successful first-stage palliation of hypoplastic left heart syndrome in neonates, the occurrence of distal aortic obstructions, shunt problems, and late deaths have led to modifications in the surgical technique. Between January 1986 and December 1987, 12 neonates from three to 16 days old underwent stage I palliation with the same objectives. An open atrial septectomy was always performed. The pulmonary artery bifurcation was transected from the main pulmonary artery and closed with an aortic homograft patch. The aortotomy was begun 2 cm below the patent ductus arteriosus insertion and extended across the transverse arch and down the ascending aorta. The neoaorta was constructed using the hypoplastic ascending aorta-transverse aortic arch, the main pulmonary artery, and an aortic homograft augmentation patch. The homograft is hemostatic and pliable, and molds well in forming the neoaorta. A 4-mm shunt was inserted between the right innominate artery and the right pulmonary artery in 5 patients and the neoaorta and the pulmonary artery bifurcation patch in 7 patients. The early systemic oxygen saturation was optimized at 75% to 80% with hyperventilation, high concentration of inspired oxygen, sodium bicarbonate, and the frequent use of vasopressors to maintain an arterial blood pressure of 65 to 75 mm Hg. Two patients (17%) died early after operation; 1 had severe right ventricular dysfunction and both had severe tricuspid regurgitation. There were 2 late deaths at 7 and 13 months, of sepsis and hypoxia. The 8 survivors (67%) continue to do well over follow-up. The preoperative tricuspid regurgitation has remained stable in 3 survivors and disappeared in 2 survivors.(ABSTRACT TRUNCATED AT 250 WORDS)

Intralobar sequestration. A missed diagnosis.

Intralobar pulmonary sequestration is an uncommon but distinct clinical entity that may be the unrecognized cause of recurrent pulmonary infections. Between 1967 and 1987, 10 patients, ranging in age from 5 to 39 years, were found to have an intralobar sequestration. Nine patients (90%) had a history of recurrent pulmonary infections, chronic cough, and intermittent fevers. One patient was asymptomatic. Many patients had been treated with antibiotics on numerous occasions. The delay in diagnosis varied between 3 months and 7 years (mean delay, 1.5 years). The chest roentgenogram was abnormal in all patients. The intralobar sequestration was present in the left lower lobe in 7 patients and the right lower lobe in 3 patients. Bronchography was abnormal in 4 patients in whom it was done. Bronchoscopy was performed in 7 patients, but it was only helpful in excluding other diagnoses. Preoperative thoracic arteriography in 9 patients visualized the systemic arterial supply from the thoracic or abdominal aorta to the intralobar sequestration and helped prevent any catastrophic surgical bleeding. A lobectomy was performed in 9 patients and a segmentectomy in 1 patient without morbidity or mortality. In patients with recurrent infections in the same lower lobe, a high index of suspicion for an intralobar sequestration should prompt early diagnostic arteriography and, if confirmed, early operative intervention.

Effects of calcium chloride administration on the postischemic isolated rat heart.

Hypercalcemic reperfusion of the postischemic heart has been associated with ventricular dysfunction and with ultrastructural changes in the mitochondria. The isolated working rat heart model was used to correlate ventricular function, mitochondrial damage, and high-energy phosphate content with degree and timing of hypercalcemia during reperfusion. When administered early during reperfusion, calcium chloride caused a dose-dependent deterioration in ventricular function, whereas calcium augmented function when it was administered after a 15-minute period of normocalcemic reperfusion. Hearts treated with calcium early during reperfusion demonstrated more mitochondrial damage and decreased stores of adenosine triphosphate than those in which calcium administration was delayed. The data indicate that a period of normocalcemic reperfusion should precede calcium administration in the postischemic heart. Mitochondrial damage resulting in decreased synthesis of adenosine triphosphate is likely the cause of ventricular dysfunction associated with calcium administration in the postischemic heart.

An alternative method for repair of partial anomalous pulmonary venous connection to the superior vena cava.

The surgical management of 15 patients with partial anomalous pulmonary venous connection (PAPVC) to the high superior vena cava (SVC) is described. This new technique redirects the anomalous pulmonary venous flow into the left atrium through the cardiac end of the SVC, transected and oversewn above the anomalous pulmonary vein or veins, by coaptation of the atrial septal defect (or of the surgically created septal defect in patients with an intact atrial septum) to the intracardiac orifice of the SVC. Normal SVC-right atrial flow is reconstituted by atriocavoplasty to the cephalad portion of the transected SVC. A 31-year-old woman with severe pulmonary hypertension died early in the series; this was the only death. Surviving patients enjoy full activity. Except for one symptomatic SVC obstruction due to technical error (since relieved), this technique has achieved total correction of these congenital defects with marked reduction in the undesirable postoperative sequelae often associated with other methods of repair.

Unusual location of an atrial myxoma complicated by a secundum atrial septal defect.

Myxomas occur most commonly in the left atrium arising from the fossa ovalis. We report the case of a left atrial myxoma originating from the base of the right inferior pulmonary vein. This large myxoma filled a large secundum atrial septal defect, which was diagnosed intraoperatively. The unusual position of this myxoma and operative management of the associated atrial septal defect are discussed.