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

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.

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

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.

A high mortality rate associated with multidrug-resistant Acinetobacter baumannii ST79 and ST25 carrying OXA-23 in a Brazilian intensive care unit.

The global spread of carbapenem-resistant Acinetobacter baumannii (A. baumannii) strains has restricted the therapeutic options available to treat infections due to this pathogen. Understanding the prevalence of such infections and the underlying genetic mechanisms of resistance may help in the implementation of adequate measures to control and prevent acquisition of nosocomial infections, especially in an intensive care unit setting. This study describes the molecular characteristics and risk factors associated with OXA-23-producing A. baumannii infections. A case-control study was undertaken from September/2013 to April/2015. Acquisition of OXA-23-producing A. baumannii was found to be associated with the use of nasogastric tubes, haemodialysis, and the use of cephalosporins. These isolates were only susceptible to amikacin, gentamicin, tigecycline, and colistin, and contained the ISAba1 insertion sequence upstream ofblaOXA-23 and blaOXA-51 genes. Twenty-six OXA-23-producing A. baumannii strains belonged to the ST79 (CC79) clonal group,and patients infected or colonised by these isolates had a higher mortality rate (34.6%). In conclusion, this study showed a dissemination of OXA-23-producing A. baumannii strains that was associated with several healthcare-related risk factors and high mortality rates among intensive care unit patients.

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

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.

Risk factors for KPC-producing Klebsiella pneumoniae: watch out for surgery.

This study describes the molecular characteristics and risk factors associated with carbapenem-resistant Klebsiella pneumoniae strains. Risk factors associated with KPC-producing K. pneumoniae strains were investigated in this case-control study from May 2011 to May 2013. Bacterial identification was performed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility was determined by broth microdilution. Carbapenemase production was assessed by both modified Hodge test (MHT) and ertapenem hydrolysis using MALDI-TOF MS. The presence of ß-lactamase-encoding genes was evaluated by PCR and DNA sequencing. Alterations in genes encoding K. pneumoniae outer membrane proteins were analysed by PCR and DNA sequencing as well as SDS-PAGE. Genetic relatedness among strains was determined by pulsed-field gel electrophoresis. This study included 94 patients. Longer hospitalisation, mechanical ventilation, catheters, and previous surgery were associated with KPC-producing K. pneumoniae. Sixty-eight strains showed resistance to carbapenems. Carbapenemase production was detected by MHT in 67 K. pneumoniae strains and by MALDI-TOF MS in 57. The presence of the blaKPC-2 gene was identified in 57 strains. The blaKPC-2 gene was not found in 11 carbapenem-resistant K. pneumoniae; instead, the blaCTX-M-1-like, blaCTX-M-2-like, blaCTX-M-8 like, blaCTX-M-14-like and blaSHV- like genes associated with OmpK35 and OmpK36 alterations were observed. Thirty-three KPC-producing K. pneumoniae strains were clonally related, and patients infected with these strains had a higher mortality rate (78.78 %). Our results show that KPC-producing K. pneumoniae was associated with several healthcare-related risk factors, including recent surgery.

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.

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.