Overview of polymyxin resistance in Enterobacteriaceae

ABSTRACT Polymyxin antibiotics are disfavored owing to their potential clinical toxicity, especially nephrotoxicity. However, the dry antibiotic development pipeline, together with the increasing global prevalence of infections caused by multidrug-resistant (MDR) gram-negative bacteria, have renewed clinical interest in these polypeptide antibiotics. This review highlights the current information regarding the mechanisms of resistance to polymyxins and their molecular epidemiology. Knowledge of the resistance mechanisms and epidemiology of these pathogens is critical for the development of novel antibacterial agents and rapid treatment choices.

High lethality rate of carbapenem-resistant Acinetobacter baumannii in Intensive Care Units of a Brazilian hospital: An epidemiologic surveillance study

ABSTRACT Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a growing threat to public health. Methods: A 3-year retrospective study was conducted to evaluate the prevalence and lethality of multidrug-resistant (MDR) A. baumannii isolated from Brazilian patients. Results: In this study, 219 Acinetobacter baumannii isolates were identified, of which 70.8% (155/219) were isolated from patients hospitalized in intensive care units. Of these, 57.4% (n = 89/155) were assessed, of which 92.1% (82/89) were carbapenem-resistant, and 49 were classified as infected. The lethality rate was 79.6% (39/49). Conclusions: We highlight the need of an effective epidemiological surveillance measure to contain the dissemination of CRAB in the hospital environment.

Multidrug-resistant Acinetobacter baumannii outbreaks: a global problem in healthcare settings

Abstract INTRODUCTION: The increase in the prevalence of multidrug-resistant Acinetobacter baumannii infections in hospital settings has rapidly emerged worldwide as a serious health problem. METHODS: This review synthetizes the epidemiology of multidrug-resistant A. baumannii, highlighting resistance mechanisms. CONCLUSIONS: Understanding the genetic mechanisms of resistance as well as the associated risk factors is critical to develop and implement adequate measures to control and prevent acquisition of nosocomial infections, especially in an intensive care unit setting.

Antibacterial activity of Cinnamomum cassia L. essential oil in a carbapenem- and polymyxin-resistant Klebsiella aerogenes strain

Abstract INTRODUCTION: Essential oils can serve as novel sources of antibiotics for multidrug-resistant bacteria. METHODS: The multidrug-resistance profile of a Klebsiella aerogenes strain was assessed by PCR and sequencing. The antibacterial activity of Cinnamomum cassia essential oil (CCeo) against K. aerogenes was assessed by broth microdilution and time-kill methods. RESULTS: K. aerogenes showed high antibiotic resistance. The genes bla KPC-2, ampC, bla CTX-M-15, bla OXA-1, and bla TEM were present. CCeo exhibited an inhibitory effect with a minimum inhibitory concentration of 17.57 μg/mL. CONCLUSIONS: The antibacterial activity of CCeo makes it a potential candidate for treating carbapenem- and polymyxin-resistant K. aerogenes strains.

Comparison of Treponema pallidum genomes for the prediction of resistance genes

Syphilis is a sexually transmitted infection caused by Treponema pallidum, which is highly prevalent in several countries,including Brazil. The use of bioinformatics’ tools for the identification of resistance genes is an important practice for thestudy of microorganisms, such as T. pallidum. In this study, the complete genomes of 43 strains of T. pallidum, isolatedfrom different countries, were analyzed. A total of 41,514 sequences were obtained, and compared against prokaryoteresistance gene databases using BLASTn, BLASTx and RGI for gene alignment and prediction. From the alignments, itwas possible to identify antibiotic resistance genes for each strain. The genes identified in each comparison were groupedaccording to the antibiotic category in which they show resistance to. The antibiotic-resistant genes related to drugs used totreat syphilis were grouped separately. The in silico tools used have shown to be effective in identifying resistance genes ingenomes of T. pallidum strains. Due to the lack of research and accurate information regarding the antibiotic resistancegenes in T. pallidum, this study serves as a basis for studies in molecular biology whose aim is the identification of thesegenes, besides being a reference to help in the control and treatment of this infection.

Origanum vulgare L. essential oil inhibits the growth of carbapenem-resistant gram-negative bacteria

Abstract INTRODUCTION: Plant products are sources for drug development against multidrug resistant bacteria. METHODS The antimicrobial activity of Origanum vulgare L. essential oil (OVeo) against carbapenem-resistant strains was assessed by disk-diffusion, microdilution (REMA-Resazurin Microtiter Assay), and time kill assays. RESULTS Carbapenemase production was confirmed for all strains. OVeo exhibited a minimum inhibitory concentration of 0.059% v/v for Klebsiella pneumoniae and Serratia marcescens, and of 0.015 % v/v for Acinetobacter baumannii. A decrease in cell count was observed after a 4 h treatment. CONCLUSIONS OVeo antimicrobial effect was rapid and consistent, making it a candidate for developing alternative therapeutic options against carbapenem-resistant strains.

Identification of São Paulo metallo-beta-lactamase-1-producing Pseudomonas aeruginosa in the Central-West region of Brazil: a case study

Abstract: Metallo-beta-lactamase production is an important mechanism for carbapenem resistance of Pseudomonas aeruginosa , which represents an emerging public health challenge. We report the case of a patient admitted to an intensive care unit, with sepsis caused by multidrug-resistant São Paulo Metallo-beta-lactamase-1-producing P. aeruginosa . This is the first case of infection by this pathogenic strain in the State of Mato Grosso do Sul, Brazil. Thus, infection control measures are required for preventing future spread and outbreaks.