Transmission of Chlamydia trachomatis through sexual partnerships: a comparison between three individual-based models and empirical data

Chlamydia trachomatis is the most common bacterial sexually transmitted infection (STI) in many developed countries. The highest prevalence rates are found among young adults who have frequent partner change rates. Three published individual-based models have incorporated a detailed description of age-specific sexual behaviour in order to quantify the transmission of C. trachomatis in the population and to assess the impact of screening interventions. Owing to varying assumptions about sexual partnership formation and dissolution and the great uncertainty about critical parameters, such models show conflicting results about the impact of preventive interventions. Here, we perform a detailed evaluation of these models by comparing the partnership formation and dissolution dynamics with data from Natsal 2000, a population-based probability sample survey of sexual attitudes and lifestyles in Britain. The data also allow us to describe the dispersion of C. trachomatis infections as a function of sexual behaviour, using the Gini coefficient. We suggest that the Gini coefficient is a useful measure for calibrating infectious disease models that include risk structure and highlight the need to estimate this measure for other STIs.

Role of Toll interleukin-1 receptor (IL-1R) 8, a negative regulator of IL-1R/Toll-like receptor signaling, in resistance to acute Pseudomonas aeruginosa lung infection

Toll interleukin-1 receptor (IL-1R) 8 (TIR8), also known as single Ig IL-1 receptor (IL-R)-related molecule, or SIGIRR, is a member of the IL-1R-like family, primarily expressed by epithelial cells. Current evidence suggests that TIR8 plays a nonredundant role as a negative regulator in vivo under different inflammatory conditions that are dependent on IL-R and Toll-like receptor (TLR) activation. In the present study, we examined the role of TIR8 in innate resistance to acute lung infections caused by Pseudomonas aeruginosa, a Gram-negative pathogen responsible for life-threatening infections in immunocompromised individuals and cystic fibrosis patients. We show that Tir8 deficiency in mice was associated with increased susceptibility to acute P. aeruginosa infection, in terms of mortality and bacterial load, and to exacerbated local and systemic production of proinflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], IL-1β, and IL-6) and chemokines (CXCL1, CXCL2, and CCL2). It has been reported that host defense against P. aeruginosa acute lung infection can be improved by blocking IL-1 since exaggerated IL-1β production may be harmful for the host in this infection. In agreement with these data, IL-1RI deficiency rescues the phenotype observed in Tir8-deficient mice: in Tir8-/- IL-1RI-/- double knockout mice we observed higher survival rates, enhanced bacterial clearance, and reduced levels of local and systemic cytokine and chemokine levels than in Tir8-deficient mice. These results suggest that TIR8 has a nonredundant effect in modulating the inflammation caused by P. aeruginosa, in particular, by negatively regulating IL-1RI signaling, which plays a major role in the pathogenesis of this infectious disease.

Wild immunology: converging on the real world

Recently, the Centre for Immunity, Infection and Evolution sponsored a one-day symposium entitled "Wild Immunology." The CIIE is a new Wellcome Trust-funded initiative with the remit to connect evolutionary biology and ecology with research in immunology and infectious diseases in order to gain an interdisciplinary perspective on challenges to global health. The central question of the symposium was, "Why should we try to understand infection and immunity in wild systems?" Specifically, how does the immune response operate in the wild and how do multiple coinfections and commensalism affect immune responses and host health in these wild systems? The symposium brought together a broad program of speakers, ranging from laboratory immunologists to infectious disease ecologists, working on wild birds, unmanaged animals, wild and laboratory rodents, and on questions ranging from the dynamics of coinfection to how commensal bacteria affect the development of the immune system. The meeting on wild immunology, organized by Amy Pedersen, Simon Babayan, and Rick Maizels, was held at the University of Edinburgh on 30 June 2011.

Predicting bacteremia in children with cancer and fever in chemotherapy-induced neutropenia: results of the prospective multicenter SPOG 2003 FN study

To develop a score predicting the risk of bacteremia in cancer patients with fever and neutropenia (FN), and to evaluate its performance.

Use of linezolid in neonatal and pediatric inpatient facilities-results of a retrospective multicenter survey

The purpose of this investigation was to describe the use of linezolid in pediatric inpatient facilities. A retrospective multicenter survey including data from nine participating tertiary care pediatric inpatient facilities in Germany and Austria was undertaken. Data on 126 off-label linezolid treatment courses administered to 108 patients were documented. The survey comprises linezolid treatment in a broad spectrum of clinical indications to children of all age groups; the median age was 6.8 years (interquartile range 0.6-15.5 years; range 0.1-21.2 years; ten patients were older than 18 years of age but were treated in pediatric inpatient units). Of the 126 treatment courses, 27 (21%) were administered to preterm infants, 64 (51%) to pediatric oncology patients, and 5% to patients soon after liver transplantation. In 25%, the infection was related to a medical device. Linezolid iv treatment was started after intensive pre-treatment (up to 11 other antibiotics for a median duration of 14 days) and changed to enteral administration in only 4% of all iv courses. In 39 (53%) of 74 courses administered to children older than 1 week and younger than 12 years of age, the dose was not adjusted to age-related pharmacokinetic parameters. In only 17 courses (13%) was a pediatric infectious disease consultant involved in the clinical decision algorithm. Linezolid seemed to have contributed to a favorable outcome in 70% of all treatment courses in this survey. Although retrospective, this survey generates interesting data on the off-label use of linezolid and highlights several important clinical aspects in which the use of this rescue antibiotic in children might be improved.

Voriconazole-induced phototoxicity in children

Voriconazole is used in antifungal prophylaxis. We performed a retrospective review of immunocompromised children receiving prophylaxis with voriconazole during major hospital renovation, who developed phototoxic skin reactions. The overall incidence of phototoxic skin reactions was 33%. A voriconazole dose of ≥6 mg/kg of body weight per dose twice daily was associated with a significantly greater risk to develop phototoxic skin reactions compared with lower doses.

Completeness of reporting in randomized controlled trials of 3 vaccines: a review of adherence to the CONSORT checklist

Clear reporting of randomized controlled trials (RCTs) of vaccines is important for understanding results and assessing their validity. The CONsolidated Standards of Reporting Trials (CONSORT) statement provides guidance to help authors reporting RCTs. The objective was to assess the completeness of reporting of RCTs of vaccines based on the CONSORT 2010 checklist.

First countrywide survey of third-generation cephalosporin-resistant Escherichia coli from broilers, swine, and cattle in Switzerland

The herd prevalence of third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec) was determined for broilers (25.0% [95% confidence interval (CI) 17.6-33.7%]), pigs (3.3% [(95% CI 0.4-11.5%]), and cattle (3.9% [95% CI 0.5-13.5%]), using a sampling strategy that was representative of the livestock population slaughtered in Switzerland between October 2010 and April 2011. The 3GC-R-Ec isolates were characterized by the measurement of the MICs of various antibiotics, microarray analyses, analytical isoelectric focusing, polymerase chain reaction and DNA sequencing for bla genes, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing. CMY-2 (n = 12), CTX-M-1 (n = 11), SHV-12 (n = 5), TEM-52 (n = 3), CTX-M-15 (n = 2), and CTX-M-3 (n = 1) producers were found. The majority of CMY-2 producers fell into 1 PFGE cluster, which predominantly contained ST61, whereas the CTX-M types were carried by heterogeneous clones of E. coli, as shown by the numerous PFGE profiles and STs that were found. This is the first national Swiss study that focuses on the spread of 3GC-R Enterobacteriaceae among slaughtered animals.

The anatomical and cellular basis of immune surveillance in the central nervous system

The central nervous system (CNS) comprises the brain, spinal cord, optic nerves and retina, and contains post-mitotic, delicate cells. As the rigid coverings of the CNS render swelling dangerous and destructive, inflammatory reactions must be carefully controlled in CNS tissues. Nevertheless, effector immune responses that protect the host during CNS infection still occur in the CNS. Here, we describe the anatomical and cellular basis of immune surveillance in the CNS, and explain how this shapes the unique immunology of these tissues. The Review focuses principally on insights gained from the study of autoimmune responses in the CNS and to a lesser extent on models of infectious disease. Furthermore, we propose a new model to explain how antigen-specific T cell responses occur in the CNS.

Clinical Characteristics of Children with Viral Single- and Co-Infections and a Petechial Rash

BACKGROUND:: Children with petechial rash are more likely to undergo invasive diagnostics, to be treated with antibiotics for potential bacterial infection and to be hospitalized. However, viruses have also been associated with petechial rash. Nonetheless, a systematic analysis of viral infections with modern available techniques as quantitative real time polymerase chain reaction (q-PCR) in the context of petechial rash is lacking. The purpose of this pediatric study was to prospectively uncover viral pathogens that may promote the emergence of petechiae and to analyze the correlation with the clinical characteristics and course. METHODS:: We conducted a prospective study in children (0 to 18 years) presenting with petechiae and signs or symptoms of infection at the emergency department between November 2009 and March 2012. In nasopharyngeal aspirates the following viruses were analyzed by q-PCR: Cytomegalovirus, Epstein-Barr virus, parvovirus B19, Influenza A and B, parainfluenza viruses, human respiratory syncytial virus A and B, human metapneumovirus, rhinovirus, enterovirus, adenovirus, human coronavirus OC43, 229E, NL63 and human bocavirus. RESULTS:: A viral pathogen was identified in 67% of the analyzed 58 cases with petechial rash. Virus positive patients showed a significantly higher incidence of lower respiratory tract infections. Forty-one percent were viral co-infections, which were significantly younger than virus negative patients, had a higher leukocyte count and were hospitalized for a longer time. CONCLUSIONS:: A petechial rash is frequently associated viral single- and co-infections and can rapidly be identified via q-PCR.

Pseudomonas aeruginosa outbreak in a pediatric oncology care unit caused by an errant water jet into contaminated siphons

We analyzed an outbreak of invasive infections with an exotoxin U positive Pseudomonas aeruginosa strain within a pediatric oncology care unit. Environmental sampling and molecular characterization of the Pseudomonas aeruginosa strains led to identification of the outbreak source. An errant water jet into the sink within patient rooms was observed. Optimized outbreak management resulted in an abundance of further Pseudomonas aeruginosa infections within the pediatric oncology care unit.

Hepatitis A vaccines and the elderly

Hepatitis A virus (HAV) exposure in unprotected adults may cause severe and serious symptoms, with risk of both morbidity and mortality increasing with age. As seroprevalence of HAV is low in industrialised countries, and an increasing number of people, with an increasing median age, travel from areas of low HAV endemicity to high endemicity, pre-travel vaccination is warranted. Vaccination of the elderly against HAV, however, may be associated with reduced seroprotection, since the immune response decreases with age. Studies with monovalent hepatitis A vaccine or combined hepatitis A and B vaccine show good efficacy in adults in general. Few studies have assessed the immune response in older adults. The only prospective study with monovalent hepatitis A vaccine in the elderly showed a reduced seroprotection of approximately 65% after a single primary dose in subjects over the age of 50 years, while seroprotection was 98% in this age group after receiving a booster dose. The only prospective study with combined hepatitis A and B vaccine in younger subjects or older than 40 years showed similar seroprotection (99-100%) against HAV compared to a monovalent vaccine after receiving three doses. As data on seroprotection for HAV in the elderly are limited, further studies are needed to elucidate how optimal protection in the elderly can be achieved. In the mean time, based on the available data, the suggestion is made to screen elderly travellers to areas endemic for HAV for the presence of naturally acquired immunity, and, if found susceptible, be immunised well in advance of their trip, to allow time for post-vaccination antibody testing and/or administration of a second dose of the vaccine.

Mansonella perstans causing symptomatic hypereosinophilia in a missionary family

Mansonella perstans is rarely pathogenic. The rare reports of symptomatic cases, however, include severe complications. Three cases of symptomatic hypereosinophilia with multi-organ involvement are described in a missionary family returning from tropical Africa. Pathogenicity may be related to the induction of hypereosinophilia rather than direct host-parasite interactions.

Reversible encephalopathy complicating post-streptococcal glomerulonephritis

We describe a 15-year-old boy with acute transient encephalopathy complicating poststreptococcal glomerulonephritis. Based on advanced magnetic resonance imaging, cerebral alterations were related to cerebrovascular autoregulatory dysfunction (ie, a vasogenic edema) and vasculitis was excluded. These insights into the pathophysiology improve patient management and argue against the therapeutic immunosuppression postulated by some authors.

Treatment options of invasive fungal infections in adults

A panel of infectious disease specialists, clinical microbiologists and hospital epidemiologists of the five Swiss university hospitals reviewed the current literature on the treatment of invasive fungal infections in adults and formulated guidelines for the management of patients in Switzerland. For empirical therapy of Candida bloodstream infection, fluconazole is the drug of choice in non-neutropenic patients with no severe sepsis or septic shock or recent exposure to azoles. Amphotericin B deoxycholate or caspofungin would be the treatment option for patients with previous azole exposure. In neutropenic patients, empirical therapy with amphotericin B deoxycholate is considered first choice. In patients with severe sepsis and septic shock, caspofungin is the drug of first choice. For therapy of microbiologically-documented Candida infection, fluconazole is the drug of choice for infections due to C. albicans, C. tropicalis or C. parapsilosis. When infections are caused by C. glabrata or by C. krusei, caspofungin or amphotericin B deoxycholate are first line therapies. Treatment guidelines for invasive aspergillosis (IA) were stratified into primary therapy, salvage therapy and combination therapy in critically ill patients. Voriconazole is recommended for primary (ie upfront) therapy. Caspofungin, voriconazole (if not used for primary therapy) or liposomal amphotericin B are recommended for salvage therapy for refractory disease. Combination therapy with caspofungin plus voriconazole or liposomal amphotericin B should be considered in critically ill patients. Amphotericin B deoxycholate is recommended as initial therapy for the empirical therapy in patients with neutropenia and persistent fever with close monitoring of adverse events.