OXA β-lactamases

The OXA β-lactamases were among the earliest β-lactamases detected; however, these molecular class D β-lactamases were originally relatively rare and always plasmid mediated. They had a substrate profile limited to the penicillins, but some became able to confer resistance to cephalosporins. From the 1980s onwards, isolates of Acinetobacter baumannii that were resistant to the carbapenems emerged, manifested by plasmid-encoded β-lactamases (OXA-23, OXA-40, and OXA-58) categorized as OXA enzymes because of their sequence similarity to earlier OXA β-lactamases. It was soon found that every A. baumannii strain possessed a chromosomally encoded OXA β-lactamase (OXA-51-like), some of which could confer resistance to carbapenems when the genetic environment around the gene promoted its expression. Similarly, Acinetobacter species closely related to A. baumannii also possessed their own chromosomally encoded OXA β-lactamases; some could be transferred to A. baumannii, and they formed the basis of transferable carbapenem resistance in this species. In some cases, the carbapenem-resistant OXA β-lactamases (OXA-48) have migrated into the Enterobacteriaceae and are becoming a significant cause of carbapenem resistance. The emergence of OXA enzymes that can confer resistance to carbapenems, particularly in A. baumannii, has transformed these β-lactamases from a minor hindrance into a major problem set to demote the clinical efficacy of the carbapenems

Dental, cephalometric and anthropometric characteristics in patients with hypohidrotic ectodermal dysplasia

ABSTRACT: The objective of this study was to describe the facial and cephalometric characteristics of 16 patients with hypohidrotic ectodermal dysplasia (HED) being treated at the College of Dentistry of the University of Antioquia and to clinically and radiographically determine which teeth were present or absent; the age of the patients ranged between 5 and 19 years. Hypohidrotic ectodermal dysplasia is a genetic syndrome that mainly affects the embryonic ectodermal originated tissues, it is manifested as a triad which includes: hypotricosis, hypohidrosis and hypodontia; it is present in one of every one hundred thousand born alive. Intraorally, a delay in tooth eruption and conoid shaped teeth are observed, affecting both jaws. Other characteristics are: prominent front and, sunken nasal bridge, retrusion of the maxilla and, protrusion of the mandible. Methods: an univariate descriptive analysis was done using frequency tables, descriptive measurements, average, bar and pie graphs for the qualitative variables and frequency histograms for the quantitative variables. The statistical analysis was done with the SPSS data base, version 15.0. Results and conclusions: the decreased anthropometric measurements were: facial width (85.5%), cutaneous mandibular height for the upper lip (75%) and total upper lip height (56.3%). The increased measurements were: upper face height (81.3%), external inter canthal distance (68.8%) and forehead width (50%). At the skeletal level the cephalometric measurements showed Class III malocclusions with hypoplastic maxillas (62.5%), retrusion (81.3%), mandibles with adequate size and position and concave profiles (75%). The most commonly absent teeth were: upper and lower lateral incisors, upper first bicuspids and lower central incisors.RESUMEN: El objetivo de esta investigación fue describir las características faciales, cefalométricas y determinar cuáles dientes estaban presentes o ausentes tanto clínica como radiográficamente en dieciséis pacientes con displasia ectodérmica hipohidrótica (DEH) de la Facultad de Odontología de la Universidad de Antioquia, en edades entre cinco y diecinueve años. La displasia ectodérmica hipohidrótica (DEH) es un síndrome de tipo hereditario que afecta principalmente los tejidos de origen ectodérmico, se manifiesta como una tríada que incluye: hipotricosis, hipohidrosis e hipodoncia; se presenta en uno de cada cien mil nacidos vivos. Intraoralmente se observa retraso en la erupción, dientes con formas conoides, afectando ambos maxilares. Otras características son: frente, labios prominentes, puente nasal hundido, retrusión del maxilar superior y protrusión mandibular. Métodos: se realizó un análisis descriptivo univariado, utilizando tablas de frecuencia, medidas descriptivas, promedio, gráficas de barras y pastel para las variables cualitativas, e histogramas de frecuencia o polígonas para las variables cuantitativas. El análisis estadístico se realizó con la base de datos SPSS versión 15.0. Resultados y conclusiones: las medidas antropométricas disminuidas fueron: ancho facial (85,5%), alturas mandibular, cutánea del labio superior (75%) y total del labio superior (56,3%). Las medidas que se encontraron aumentadas fueron: altura facial superior (81,3%), distancia intercantal externa (68,8%) y ancho de la frente (50%). En el esqueleto las medidas cefalométricas mostraron en general maloclusiones clase III con maxilares hipoplásicos (62,5%), retrusivos (81,3%), mandíbulas de tamaño y posición adecuada, con perfiles cóncavos (75%). Los dientes que más tuvieron ausencias fueron: laterales superiores e inferiores, primeros premolares superiores y centrales inferiores

Genomics of Klebsiella pneumoniae ST16 producing NDM-1, CTX-M-15, and OXA-232

OBJECTIVES: Genomic characterization of the internationally spread sequence type (ST) 16 carbapenem-resistant Klebsiella pneumoniae. METHODS: The complete genomes of three carbapenem producing ST16 K. pneumoniae from Italian patients were analysed by single-nucleotide polymorphism-based phylogeny, core genome multilocus sequence typing, resistance, plasmid, and virulence content and compared with ten genomes of ST16 strains isolated in other countries. Plasmids carrying blaNDM-1 or blaOXA-232 carbapenemase genes were assembled and sequences were analysed. RESULTS: The internationally spread ST16 K. pneumoniae clone showed variability in terms of distribution of NDM-1 and OXA-232 type carbapenemases. In some ST16 strains, up to six plasmids can be simultaneously present in the same cell, including ColE-like plasmids carrying blaOXA-232 and IncF plasmids carrying blaNDM-1. The differences observed in plasmid, resistance, and virulence content and core genome suggested that there is not a unique, highly conserved ST16 clone, but instead different variants of this lineage circulate worldwide. CONCLUSIONS: The ST16 K. pneumoniae clone has spread worldwide and may become a high-risk clone

First Report of an OXA-23 Carbapenemase-Producing Acinetobacter baumannii Clinical Isolate Related to Tn2006 in Spain

A carbapenem-resistant Acinetobacter baumannii clinical isolate belonging to European clone II and sequence type 2 was recov-ered from a patient in the Son Espases hospital in Mallorca, Spain. Genetic analysis showed the presence of the bla OXA-23 gene in association with the widely disseminated transposon Tn2006. This is the first reported identification of A. baumannii carrying bla OXA-23 in Spain

Evaluación de los cambios esqueléticos y dentales producidos con el tratamiento con placas de acetato y elásticos de clase III en pacientes con mesio-relación esquelética y dental en dentición primaria o mixta temprana

ABSTRACT: Several authors have suggested the early treatment of oclusal alterations looking forward to change craniofacial growth conditions and diminish their expression with different appliances, one of them proposed by Franchi and Baccetti in 1998 for cases of mesiorrelations, which consists in bimaxilar resin splints with smooth oclusal planes and class III intermaxillary elastics. The present study pretended to evaluate the cephalometric and clinic changes with this therapy in 9 patients 4 and 7 years old with skeletal mesiorrelation during one year of treatment. Cephalic X-rays and dental casts were taken to each patient before starting the treatment at six months and one year later. The results show skeletal and dentoalveolar changes in the maxilla and the mandible. On the vertical plane it is suggested that a sagittal dysplasia compensation occurs and the changes in the soft tissues suggested the enhancement of facial aesthetics. It can be concluded that the therapy works positively in the mesio – relation in the children studied.RESUMEN: Varios autores han sugerido el tratamiento temprano de las alteraciones oclusales con el fin de cambiar las condiciones de crecimiento craneofacial y disminuir la expresión de las mismas y han sugerido diferentes aparatologías, una de ellas es la propuesta por Franchi y Baccetti en 1998 para las mesiorrelaciones, que consiste en placas de acetato bimaxilares con planos oclusales lisos y elásticos claseIII. Este estudio, evaluó los cambios clínicos y cefalométricos obtenidos con dicha terapia en 9 pacientes entre 4 y 7 años con mesiorrelación esquelética durante un año de tratamiento. Se tomaron radiografías cefálicas laterales y modelos de estudio antes, a los seis meses y al finalizar el tratamiento. Los resultados indican cambios positivos esqueléticos y dentoalveolares, tanto en el maxilar como en la mandíbula. En el plano vertical los cambios sugieren compensación de la displasia sagital por la rotación mandibular y los cambios en los tejidos blandos mostraron mejoramiento en la estética facial. Se puede concluir que la terapia es favorable para el mejoramiento de la mesiorrelación en los niños estudiados

Standardized Treatment of Active Tuberculosis in Patients with Previous Treatment and/or with Mono-resistance to Isoniazid: A Systematic Review and Meta-analysis

Performing a systematic review of studies evaluating retreatment of tuberculosis or treatment of isoniazid mono-resistant infection, Dick Menzies and colleagues find a paucity of evidence to support the WHO-recommended regimen

Rationing tests for drug-resistant tuberculosis - who are we prepared to miss?

BACKGROUND: Early identification of patients with drug-resistant tuberculosis (DR-TB) increases the likelihood of treatment success and interrupts transmission. Resource-constrained settings use risk profiling to ration the use of drug susceptibility testing (DST). Nevertheless, no studies have yet quantified how many patients with DR-TB this strategy will miss. METHODS: A total of 1,545 subjects, who presented to Lima health centres with possible TB symptoms, completed a clinic-epidemiological questionnaire and provided sputum samples for TB culture and DST. The proportion of drug resistance in this population was calculated and the data was analysed to demonstrate the effect of rationing tests to patients with multidrug-resistant TB (MDR-TB) risk factors on the number of tests needed and corresponding proportion of missed patients with DR-TB. RESULTS: Overall, 147/1,545 (9.5%) subjects had culture-positive TB, of which 32 (21.8%) had DR-TB (MDR, 13.6%; isoniazid mono-resistant, 7.5%; rifampicin mono-resistant, 0.7%). A total of 553 subjects (35.8%) reported one or more MDR-TB risk factors; of these, 506 (91.5%; 95% CI, 88.9-93.7%) did not have TB, 32/553 (5.8%; 95% CI, 3.4-8.1%) had drug-susceptible TB, and only 15/553 (2.7%; 95% CI, 1.5-4.4%) had DR-TB. Rationing DST to those with an MDR-TB risk factor would have missed more than half of the DR-TB population (17/32, 53.2%; 95% CI, 34.7-70.9). CONCLUSIONS: Rationing DST based on known MDR-TB risk factors misses an unacceptable proportion of patients with drug-resistance in settings with ongoing DR-TB transmission. Investment in diagnostic services to allow universal DST for people with presumptive TB should be a high priority