Phenotypic and genotypic characterization of enteroaggregative Escherichia coli isolates from pediatric population in Pakistan

Enteroaggregative Escherichia coli (EAEC) are a leading cause of diarrhea among children. The objective of this study was to define the frequency of EAEC among diarrheal children from flood‐affected areas as well as sporadic cases, determine multidrug resistance, and evaluation of virulence using an in vivo model of pathogenesis. Stool samples were collected from 225 diarrheal children from 2010 to 2011 from flood‐affected areas as well as from sporadic cases in Pakistan. Identified EAEC isolates were characterized by phylogrouping, antibiotic resistance patterns including the extended‐spectrum beta lactamase spectrum, single nucleotide polymorphism detection in gyrA and parC, and virulence potential using wax worm, G. mellonella. A total of 35 (12.5%) confirmed EAEC isolates were identified among 225 E. coli isolates. EAEC isolates displayed high resistance to tetracycline, ampicillin, and cefaclor. A total of 34.28% were ESBL positive. Single nucleotide polymorphism detection revealed 37.14% and 68.57% isolates were positive for SNPs in gyrA (A₆₆₀‐T₆₆₀) and parC (C₃₃₀‐T₃₃₀), respectively. Phylogrouping revealed that B2 phylogroup was more prevalent among all EAEC isolates tested followed by D, A, B1, and non‐typeable (NT). Infection of G. mellonella with EAEC showed that killing infective dose was 100% higher than E. coli DH5 alpha control. EAEC are prevalent among Pakistani children with diarrhea, they are highly resistant to antibiotics, and predominantly fall into B2 phylogroup. Epidemiologic surveillance of EAEC and other E. coli pathotypes is critical to assess not only the role of these pathogens in diarrheal disease but also to determine the extent of multidrug resistance among the population.     

Routine childhood vaccination programme coverage,El Salvador, 2011—In search of timeliness

While assessing immunization programmes, not only vaccination coverage is important, but also timely receipt of vaccines. We estimated both vaccination coverage and timeliness, as well as reasons for non-vaccination, and identified predictors of delayed or missed vaccination, for vaccines of the first two years of age, in El Salvador.     

Nonrenewal spike train statistics: causes and functional consequences on neural coding

Many neurons display significant patterning in their spike trains (e.g. oscillations, bursting), and there is accumulating evidence that information is contained in these patterns. In many cases, this patterning is caused by intrinsic mechanisms rather than external signals. In this review, we focus on spiking activity that displays nonrenewal statistics (i.e. memory that persists from one firing to the next). Such statistics are seen in both peripheral and central neurons and appear to be ubiquitous in the CNS. We review the principal mechanisms that can give rise to nonrenewal spike train statistics. These are separated into intrinsic mechanisms such as relative refractoriness and network mechanisms such as coupling with delayed inhibitory feedback. Next, we focus on the functional roles for nonrenewal spike train statistics. These can either increase or decrease information transmission. We also focus on how such statistics can give rise to an optimal integration timescale at which spike train variability is minimal and how this might be exploited by sensory systems to maximize the detection of weak signals. We finish by pointing out some interesting future directions for research in this area. In particular, we explore the interesting possibility that synaptic dynamics might be matched with the nonrenewal spiking statistics of presynaptic spike trains in order to further improve information transmission.     

Medical students’ skills in image interpretation before and after training: A comparison between 3rd-year and 6th-year students from two different medical curricula

The purpose of this study was to assess student's performance in the interpretation of images before and after training in radiology, by comparing two groups, 6th-year and 3rd-year students, from two different medical curricula. Students participated in an anonymous evaluation consisting of the interpretation of 12 radiological images accompanied with the salient history and clinical data by answering 60 open-ended questions about technique, anatomy, semiology, and clinics. The number of correct, incorrect and blank responses of each group was used to compare pre- and post-training results. Unpaired two-sample t-test was used to evaluate differences between groups. A significant increase in correct responses was found in both groups after training. The comparison between both groups did not show differences for incorrect answers of the whole test and correct answers about anatomy in the pre-training evaluation. The percentage of correct answers to the median question improved from 15.5% to 53.3% for 6th-year students and from 8.3% to 41.1% for 3rd-year students. The post-training evaluation showed a significant increase of correct answers of 6th-year students with respect to 3rd-year students (mean ± standard deviation 53.6 ± 31.3% and 38.7 ± 29.9% respectively), mainly due to differences in technical and clinical questions. This study provides objective and quantitative evidence of pre- and post-training student skills in image interpretation. The similarities found in the previous level of knowledge and skills of both groups emphasizes the suitable change of the first-time training in radiology, from the 6th to the 3rd year course in medical curricula.     

From recipe to research: introducing undergraduate students to the nature of science using a hybrid practical course centred on drug discovery for neglected diseases

1. Download : Download high-res image (93KB)
2. Download : Download full-size image