ABSTRACT
Bacteriophage-encoded single strand annealing proteins (SSAPs) are recombinases which can substitute the classical, bacterial RecA and manage the DNA metabolism at different steps of phage propagation. SSAPs have been shown to efficiently promote recombination between short and rather divergent DNA sequences and were exploited for in vivo genetic engineering mainly in Gram-negative bacteria. In opposition to the conserved and almost universal bacterial RecA protein, SSAPs display great sequence diversity. The importance for SSAPs in phage biology and phage-bacteria evolution is underlined by their role as key players in events of horizontal gene transfer (HGT). All of the above provoke a constant interest for the identification and study of new phage recombinase proteins in vivo, in vitro as well as in silico. Despite this, a huge body of putative ssap genes escapes conventional classification, as they are not properly annotated. In this work, we performed a wide-scale identification, classification and analysis of SSAPs encoded by the Firmicutes bacteria and their phages. By using sequence similarity network and gene context analyses, we created a new high quality dataset of phage-related SSAPs, substantially increasing the number of annotated SSAPs. We classified the identified SSAPs into seven distinct families, namely RecA, Gp2.5, RecT/Redß, Erf, Rad52/22, Sak3, and Sak4, organized into three superfamilies. Analysis of the relationships between the revealed protein clusters led us to recognize Sak3-like proteins as a new distinct SSAP family. Our analysis showed an irregular phylogenetic distribution of ssap genes among different bacterial phyla and specific phages, which can be explained by the high rates of ssap HGT. We propose that the evolution of phage recombinases could be tightly linked to the dissemination of bacterial phage-resistance mechanisms (e.g., abortive infection and CRISPR/Cas systems) targeting ssap genes and be a part of the constant phage-bacteria arms race.
ABSTRACT
Resumen OBJETIVO: Identificar los desenlaces perinatales en recién nacidos de madres infectadas con el virus del Zika durante el embarazo. MATERIALES Y MÉTODOS: Estudio observacional, descriptivo, retrospectivo de corte longitudinal, llevado a cabo en el Hospital Regional de Alta Especialidad de la Mujer de Villahermosa, Tabasco, entre enero de 2016 y diciembre de 2017. Se incluyeron todas las pacientes con infección por el virus del Zika, confirmado mediante PCR-RT en suero, que finalizaron el embarazo en el hospital. Las variables de estudio fueron: semanas de gestación y trimestre en el que se estableció el diagnóstico; relación ecográfica de acuerdo con el diámetro biparietal y perímetro cefálico según la edad gestacional; al nacimiento se evaluó la somatometría, alteraciones congénitas, estimación del percentil del perímetro cefálico para la edad gestacional. Para determinar la microcefalia, se utilizó como parámetro el percentil menor de 5 del perímetro cefálico para edad gestacional. RESULTADOS: La muestra total fue de 37 pacientes. El promedio de edad materna fue de 25 años. En 17 de 37 pacientes de estableció el diagnóstico de la infección en el primer trimestre del embarazo; se observó crecimiento proporcional entre las semanas de gestación y las medidas cefálicas durante el seguimiento ultrasonográfico. Se encontró un feto con percentil menor de 5 del diámetro biparietal a las 18.5 semanas, con dilatación del cuarto ventrículo y agrandamiento de la fosa posterior, sugerente de síndrome de Dandy-Wallker. El resto de los fetos fueron sanos. CONCLUSIÓN: Se registró un caso de síndrome de Dandy-Wallker secundario a trisomía 18, comprobada por cariotipo. No se encontraron defectos congénitos atribuibles al virus del Zika en el resto de los pacientes.
Abstract OBJECTIVE: To know the perinatal outcomes in children of infected mothers during pregnancy Zika virus. MATERIALS AND METHODS: An observational, descriptive, longitudinal retrospective study conducted at the Regional Hospital of High Specialty of Women (HRAEM) in Villahermosa Tabasco, from January 2016 to December 2017, included all pregnant women with Zika virus infection confirmed by the State Public Health laboratory using serum RT-PCR, who have completed pregnancy in the HRAEM. the variables studied were: the SDG and diagnostic quarter, ultrasound relationship according to biparietal diameter and cephalic perimeter according to gestational age, at birth the somatometry was evaluated, presence of congenital alterations, cephalic perimeter percentile for gestational age, was used as parameter to determine microcephaly the percentile <5 of the cephalic perimeter for gestational age. RESULTS: The total sample was 37 patients, with maternal age average of 25 years, with 17 of 37 detection in the first trimester of pregnancy, a proportional growth between weeks of gestation and cephalic measures during ultrasonographic follow-up was observed. One fetus was found below the 5th percentile of the biparietal diameter at 18.5 weeks, with dilation of the fourth ventricle and enlargement of the posterior fossa, images suggestive of probable Dandy Wallker syndrome. All other fetuses were found normal. CONCLUSION: At birth, Dandy Wallker syndrome was confirmed in a patient secondary to trisomy 18 corroborated by karyotype. No congenital defects attributable to Zika virus were found in the rest of the patients.
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OBJECTIVE To investigate the distribution and drug resistance of nosocomial infection pathogens. METHODS Statistical methods were used to analyz the data of pathogens origin and drug resistance from 2005 to 2007. RESULTS A total of 326 strains were isolated from 604 nosocomial infection cases (54.0%),from which the Gram-negative bacilli were predominate (44.1%). The isolation rate ot fungi and Gram-positie bacteria was 41.6% and 14.3%,respectiviely. The top three pathogens were the fungi (41.6%),Pseudomonas aeruginosa14.3%,and enterobacter (10.6%). The rate of ampicillin-resistant Escherichia coli was 100%.The isolation rate of MRSA and MRCNS was up to 100.0% and 80.0%. CONCLUSIONS Fungi is common high among pathogens.The emergence of drug-resistant pathogens will continue to be a serious problem,we must take it intimately.
ABSTRACT
[Objective]To examine the effect and safety of the combination of rifampin plus levofloxacin given orally for treating chronic orthopedic implant-related infections. [Methods]From March 2006 to December 2007,13 patients with chronic orthopedic implant-related infections were treated orally with rifampin ,600 mg/day,plus levofloxacin,600mg/day.The study group included 6 males and 7 females, with average age of 51.6 years (range, 17~75 years).During treatment,clinical follow-up was performed, including blood and differential counts ,erythrocyte sedimentation rate , and hepatic enzyme levels,C-reactive protein levels,and radiological data.Cure was defined as the absence of clinical signs and symptoms of infection (fever,local pain,redness,warmth,sinus tract infection ),ESR50 mg/l) without microbiological documentation of infection.[Results]Among 13 patients included in the study and evaluable for safety, one patient had gastrointestinal side effects and was not evaluable for treatment effectiveness. Twelve patients with chronic orthopedic implant-related infections , antibiotics were administrated orally for a total of 6 months . Two patients, on whom pseudoarthrosis presented, were treated with autologous bone graft and internal fixation subsequently. Ten of 12 patients with chronic orthopedic implant-related infections had successful outcomes . Those rates were determined after a post-treatment follow-up of 6 to 27 months (average, 24 months ).The overall success rate was 83.3% among 12 patients.Ten cases had been followed up,and no case had infection recurrence.[Conclusion]With nutrition support, the combination of rifampin plus levofloxacin given orally for treating chronic orthopedic implant-related infections are effective methods.
