Genetic heterogeneity and predominance of blaCTX-M -15 in cefotaxime-resistant Enterobacteriaceae isolates colonizing hospitalized children in Tunisia.

Extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae have emerged as important nosocomial pathogens. Community infections by these organisms have been also reported and were associated with previous intestinal colonization. We aimed to characterize cefotaxime-resistant Enterobacteriaceae (CTX-R-En) isolated from hospitalized children in a Tunisian paediatric ward. Seventy CTX-R-En isolates were collected from 227 rectal swabs from hospitalized children in a paediatric ward. Antimicrobial susceptibility testing was determined according to the EUCAST guidelines. Isolates were characterized by polymerase chain reaction (PCR, genes encoding: ESBLs, pAmpC, carbapenemases, plasmid-mediated quinolone resistance, virulence factors in Escherichia coli and Klebsiella pneumoniae isolates, occurrence of classes 1 and 2 integrons, phylogenetic groups of E. coli isolates, ERIC-PCR and PCR-based replicon typing) and conjugal transfer experiments. In total, 65 out of 227 (28·6%) hospitalized children were colonized with CTX-M-R-En, and 70 isolates were identified. Isolates were 59 ESBL-, 7 plasmidic-AmpC (pAmpC)-, 3 ESBL+pAmpC-, and one ESBL+carbapenemase producers. The following bla genes were identified: blaCTX-M-15 (n = 54), blaCTX-M-1 (n = 5), blaCTX-M-9 (n = 2), blaCTX-M-13 (n = 1) and blaCTX-M-14 (n = 1), blaCMY-2 (n = 5), blaCMY-4 (n = 4), blaACC-1 (n = 1) and blaOXA-48 (n = 1). Our results showed that hospitalized children were colonized with various CTX-R-En-producing several beta-lactamase enzymes.

End-stage renal disease in Tunisian infants: Etiology and outcome.

End stage renal disease (ESRD) in infants has particular features in terms of etiologies and therapeutic modalities. The aim of our study is to describe the etiologies and the ESRD outcomes among Tunisian infants. This retrospective study was conducted over 15 years (from January 1998 to December 31, 2013) in the Pediatric Department at Charles Nicolle Hospital. In total, 157 pediatric patients had ESRD. The mean incidence was 4.25 million children. The study involved 24 infants; the sex ratio was equal to 2. The mean age at diagnosis of ESRD was 8 months (range, 1-21 months). Growth retardation was noticed in 14 patients. The main causes were Congenital Anomalies of the Kidneys and Urinary Tract (9 infants) and hereditary renal disease (9 infants). All patients were treated with peritoneal dialysis; 16 infants presented peritonitis. Mortality rate was about 28%. The leading causes of death were cardiovascular diseases and infections.

Compressive behavior of a turtle's shell: experiment, modeling, and simulation.

The turtle's shell acts as a protective armor for the animal. By analyzing a turtle shell via finite element analysis, one can obtain the strength and stiffness attributes to help design man-made armor. As such, finite element analysis was performed on a Terrapene carolina box turtle shell. Experimental data from compression tests were generated to provide insight into the scute through-thickness behavior of the turtle shell. Three regimes can be classified in terms of constitutive modeling: linear elastic, perfectly inelastic, and densification regions, where hardening occurs. For each regime, we developed a model that comprises elasticity and densification theory for porous materials and obtained all the material parameters by correlating the model with experimental data. The different constitutive responses arise as the deformation proceeded through three distinctive layers of the turtle shell carapace. Overall, the phenomenological stress-strain behavior is similar to that of metallic foams.