Características de virulência, resistência e diversidade genética de sorovares de Salmonella com impacto na saúde pública, isolados de frangos de corte no Brasil /

Salmonella Enteritidis, S. Typhimurium and S. Infantis are often associated with cases of human infections worldwide and is transmitted through consumption of contaminated food, particularly those of animal origin, especially chicken meat. This thesis was fractionated into three chapters, the first one relating to general considerations about the topics discussed in the following chapters. The second chapter aimed to evaluate virulence characteristics, antimicrobial resistance and the genetic similarity of 51 strains of S. Infantis isolated in samples of poultry origin from an industry located in the state of São Paulo, Brazil, during the 2009 to 2010 period. The third chapter aimed to analyze 111 strains of S. Enteritidis, 45 of Salmonella Typhimurium and 31 of Salmonella Typhimurium monophasic variant I 4, [5], 12:i:- isolated from chicken carcasses in different brazilian slaughterhouses from 2009 to 2011, and to estimate the risk to human health, based on the presence of virulence genes and antimicrobial resistance, correlating to the pathogenicity profiles (antimicrobial resistance and presence of virulence and resistance genes) with the genetic profile (ribogroup) of the isolates. To evaluate the antimicrobial susceptibility was performed the disk diffusion test for all serotypes of Salmonella, and exclusively to S. Enteritidis and S. Typhimurium, was also verified the minimum inhibitory concentration for ciprofloxacin and ceftazidime antibiotics. The presence of virulence genes invA (invasion), lpfA (fimbriae-adhesion), agfA (fimbriae-biofilm) and sefA (fimbriae-adhesion) were evaluated by PCR. The strains that showed resistance to antibiotics of β-lactams class were evaluated for the presence of resistance genes blaTEM, blaSHV, blaCTX-M and blaAmpC. For resistant strains to quinolones and fluoroquinolones antibiotics classes were searched the qnrA and qnrS genes. The phylogenetic relationship among the isolates was determined by RAPD method for S. Infantis strains, and by ribotyping technique to S. Enteritidis and S. Typhimurium.

Infecções por enterobacteriaceae resistente aos carbapenêmicos em hospital de ensino: epidemiologia e caracterização molecular

Introduction: The production of KPC (Klebsiella pneumoniae carbapenemase) has become an important mechanism of carbapenem-resistance among Enterobacteriaceae strains. In Brazil, KPC is already widespread and its incidence has increased significantly, reducing treatment options. The “perfect storm” combination of the absence of new drug developmentand the emergence of multidrug-resistant strains resulted in the need for the use of older drugs, with greater toxicity, such as polymyxins. Aims: To determine the occurrence of carbapenemase-producing strains in carbapenem-resistant Enterobacteriaceae isolated from patients with nosocomial infection/colonization during September/2014 to August/2015, to determine the risk factors associated with 30-day- mortality and the impact of inappropriate therapy. Materials and Methods: We performed a case control study to assess the risk factors (comorbidities, invasive procedures and inappropriate antimicrobial therapy) associated with 30-day-mortality, considering the first episode of infection in 111 patients. The resistance genes blaKPC, blaIMP, blaVIM and blaNDM-1 were detected by polymerase chain reaction technique. Molecular typing of the strains involved in the outbreak was performed by pulsed field gel electrophoresis technique. The polymyxin resistance was confirmed by the microdilution broth method. Results: 188 episodes of carbapenem-resistant Enterobacteriaceae infections/colonizations were detected; of these, 122 strains were recovered from the hospital laboratory. The presence of blaKPC gene were confirmed in the majority (74.59%) of these isolates. It was not found the presence of blaIMP , blaVIM and blaNDM-1 genes. K. pneumoniae was the most frequent microorganism (77,13%), primarily responsible for urinary tract infections (21,38%) and infections from patients of the Intensive Care Unit (ICU) (61,38%). Multivariate statistical analysis showed as predictors independently associated with mortality: dialysis and bloodstream infection. The Kaplan-Meier curve showed a lower probability of survival in the group of patients receiving antibiotic therapy inappropriately. Antimicrobial use in adult ICU varied during the study period, but positive correlation between increased incidence of strains and the consumption was not observed. In May and July 2015, the occurrence rates of carbapenem-resistant Enterobacteriaceae KPC-producing per 1000 patient-days were higher than the control limit established, confirming two outbreaks, the first caused by colistin-susceptible KPC-producing K. pneumoniae isolates, with a polyclonal profile and the second by a dominant clone of colistin-resistant (≥ 32 μg/mL) KPC-producing K. pneumoniae. The cross transmission between patients became clear by the temporal and spatial relationships observed in the second outbreak, since some patients occupied the same bed, showing problems in hand hygiene adherence among healthcare workers and inadequate terminal disinfection of environment. The outbreak was contained when the ICU was closed to new admissions. Conclusions: The study showed an endemicity of K. pneumoniae KPC-producing in adult ICU, progressing to an epidemic monoclonal expansion, resulted by a very high antibiotic consumption of carbapenems and polymyxins and facilitated by failures in control measures the unit.