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.

Brote por Serratia marcescens en una Unidad de Cuidados Intensivos Neonatales: Guayaquil-Ecuador / Serratia marcescens outbreak in Neonatal Intensive Care Unit: Guayaquil, Ecuador

We report a Serratia marcescens outbreak occurred in the NICU of a pediatric hospital in Guayaquil, Ecuador. Nine cases of infection were detected, from which septicemia was developed in 55.5%. The index case was a newborn derived from another institution with septic arthritis caused by the outbreak strain. The infection rate was 17.6% and mortality rate was 33.3%. All isolates were resistant to aminoglycosides and susceptible to third generation cephalosporins and carbapenems. Clonality analysis by pulsed-field gel electrophoresis (PFGE) revealed the presence of two closely related clones confirming the horizontal spread. Measures were taken by the committee such as: strengthening the hand hygiene, patient hygiene and cohort studies of gastrointestinal colonization, which allowed the control of the outbreak.

Comunicamos un brote nosocomial por Serratia marcescens en una Unidad de Cuidados Intensivos en un hospital pediátrico de Guayaquil, Ecuador. Se detectaron nueve casos de infección, manifestándose en 55,5% de los casos como sepsis. El caso índice correspondió a un neonato derivado de otra institución con artritis séptica. La tasa de ataque fue 17,6% (n: 51) y la mortalidad 33,3%. Todos los aislados presentaron resistencia a las cefalosporinas y aminoglucósidos y sensibilidad a carbapenémicos. El análisis de clonalidad reveló la presencia de dos clones estrechamente relacionados, confirmando la diseminación horizontal. Las medidas de control de brote fueron: reforzamiento de higiene de manos, cohorte de los pacientes y búsqueda de colonización gastrointestinal.

Risk Factors for Mortality in Patients with Serratia marcescens Bacteremia

PURPOSE: Over the last 30 years, Serratia marcescens (S. marcescens) has emerged as an important pathogen, and a common cause of nosocomial infections. The aim of this study was to identify risk factors associated with mortality in patients with S. marcescens bacteremia. MATERIALS AND METHODS: We performed a retrospective cohort study of 98 patients who had one or more blood cultures positive for S. marcescens between January 2006 and December 2012 in a tertiary care hospital in Seoul, South Korea. Multiple risk factors were compared with association with 28-day all-cause mortality. RESULTS: The 28-day mortality was 22.4% (22/98 episodes). In a univariate analysis, the onset of bacteremia during the intensive care unit stay (p=0.020), serum albumin level (p=0.011), serum C-reactive protein level (p=0.041), presence of indwelling urinary catheter (p=0.023), and Sequential Oran Failure Assessment (SOFA) score at the onset of bacteremia (p<0.001) were significantly different between patients in the fatal and non-fatal groups. In a multivariate analysis, lower serum albumin level and an elevated SOFA score were independently associated with 28-day mortality [adjusted odds ratio (OR) 0.206, 95% confidential interval (CI) 0.044-0.960, p=0.040, and adjusted OR 1.474, 95% CI 1.200-1.810, p<0.001, respectively]. CONCLUSION: Lower serum albumin level and an elevated SOFA score were significantly associated with adverse outcomes in patients with S. marcescens bacteremia.

The Emergence of the 16S rRNA Methyltransferase RmtB in a Multidrug-Resistant Serratia marcescens Isolate in China

No abstract available.

Discovery of a Fluoroquinolone-Resistant Serratia marcescens Clinical Isolate without Quinolone Resistance-Determining Region Mutations

No abstract available.

Comparison of Antimicrobial Effect of Alcohol Gel according to the Amount and Drying Time in Health Personnel Hand Hygiene

PURPOSE: The purpose of this study was to compare the effect of alcohol gel according to the amount and drying time in health personnel hand hygiene and to promote in their practice adequate and effective hand hygiene. METHODS: The cross-over experimental study was performed with 14 volunteers. Hands were artificially contaminated with 5 mL of 10(8) CFU/mL of Serratia marcescens (ATCC 14756) and four different alcohol gel hand hygiene methods varying by the amount of alcohol gel (2 mL vs. 1 mL) and drying time (complete vs. incomplete) were compared. Samples were collected by glove juice sampling procedures. RESULTS: Mean log reduction values of the four different hand hygiene methods were 2.22+/-0.36, 1.26+/-0.53, 1.49+/-0.60, 0.89+/-0.47 respectively for the 4 groups: adequate amount (2mL) and complete dry (30 seconds rubbing followed by 2 min air-dry), inadequate amount (1 mL) and complete dry, adequate amount and incomplete dry (15 seconds rubbing and no air-dry), and inadequate amount and incomplete dry. The difference was statistically significant in the adequate amount and complete dry group compared to other three groups (p<.001). CONCLUSION: Only alcohol gel hand hygiene with adequate amount and complete drying was satisfactory by U.S. FDA-TFM efficacy requirements for antiseptic hand hygiene products.

Gene expression analysis of the SdeAB multidrug efflux pump in antibiotic-resistant clinical isolates of Serratia marcescens.

Purpose: Many isolates of Serratia marcescens, a well-known opportunistic pathogen, can be multidrug resistant. Fluoroquinolones are among the most important groups of antibiotics used for treatment of these organisms. However, fluoroquinolone resistance among S. marcescens isolates is fast increasing. Drug extrusion through efflux pumps like SdeAB/ HasF is one of the major mechanisms of resistance to fluoroquinolones. This study was carried out to analyze, through gene expression analysis of sdeB, the relative contribution of this mechanism toward fluoroquinolone resistance in clinical isolates of Serratia. Materials and Methods: Total RNA from 45 clinical isolates of S. marcescens was isolated. Quantitative real-time RT PCR was performed on the extracted RNA to study the gene expression of sdeB and was normalized to the sdeB expression in the standard strain of S. marcescens. Results: Of the 45 isolates analyzed, sdeB expression was found to be elevated in 20 isolates (44%). Of these 20 isolates, eight (40%) were fully resistant to at least one of the fluoroquinolones studied. Conversely, of the 20 isolates that over-expressed sdeB, 12 (60%) were fully sensitive to all fluoroquinolones tested. Conclusions: Drug efflux pumps are an important means of fluoroquinolone resistance among clinically important species ofSerratia. The expression of these pumps can be up-regulated in the presence of antibiotics and have the potential for changing the phenotype from sensitive to resistant, thus contributing to therapeutic failures.

Antimicrobial resistance in 11 hospitals in Puerto Rico: results of an antimicrobial resistance management (ARM) program

PURPOSE: The Antimicrobial Resistance Management Program (ARMP) was established in 1997 at the University of Florida as an ongoing project to document trends in antimicrobial susceptibility patterns in inpatient/outpatient isolates and track resistance that may occur with specific antibiotic use. METHODS: Institutions are enrolled at no charge and provide a minimum of 3 years of antibiogram/sensitivity report data, which are reviewed to create a customized analysis of antimicrobial susceptibility trends benchmarked against national/regional comparators. The data, in a HIPAA-compliant non-identifying format, comprise a national aggregate database of 28.4 million isolates from 358 institutions. This database was interrogated to determine resistance rates for eleven hospitals in Puerto Rico from 1998-2003 and, as comparators, those in the database from the State of Florida and all U.S. institutions. RESULTS: Between 1996-2003, data on 328,837 isolates collected from 11 hospitals throughout Puerto Rico, 5,388,897 isolates from 46 institutions in Florida, and 24,951,098 isolates from 358 U.S. institutions for the following organisms (number of antibiotics tested against) were reviewed for susceptibility: coagulase-negative staphylococci (14)/Staphylococcus epidermidis (18), Enterococcus faecalis (7), Enterococcus faecium (5), Enterococcus species (4), Escherichia coli (24), Klebsiella pneumoniae (24), Proteus mirabilis (22), Pseudomonas aeruginosa (14), Serratia marcescens (22), Staphylococcus aureus (23), and Streptococcus pneumoniae (9). Antimicrobial resistance in Puerto Rico varied organism to organism from that observed in Florida and nationally. CONCLUSIONS: This first broad analysis of antimicrobial resistance in Puerto Rico provides important baseline data, both for sentinel surveillance programs and for determining strategies for intervention.

Transferecia de de ß-lactamasas de espectro extendido desde cepas hospitalarias de Klebsiella pneumoniae a otras especies de enterobacterias / Transference of extended-spectrum ß-lactamases from nosocomial strains of Klebsiella pneumoniae to other species of Enterobacteriaceae

Background: Klebsiella pneumoniae is an important pathogenic bacterium, frequently isolated from nosocomial samples, that exhibits wide antimicrobial resistance profiles, including third generation cephalosporins (3GC), aminoglycosides and quinolones. The resistance to 3GC is mainly due to the synthesis of extended spectrum beta lactamases (ESBL), encoded by conjugative plasmids. Aim: To investigate the potential transference of resistance to 3GC from nosocomial strains of K. pneumoniae to other clinical strains of various species of Enterobacteriaceae. Material and methods: The mating experiments were carried out in liquid media and three nosocomial strains of K. pneumoniae were used as donors. These strains were ESBL-producers and resistant to, at least, one of the 3GC assayed. One strain of Citrobacter freundii, Salmonella typhimurium, Serratia marcescens and Escherichia coli, isolated from clinical specimens, were used as recipients. The presence of bla genes was investigated by PCR. Results: The three nosocomial strains of K. pneumoniae were able to transfer the resistance to 3GC and the genes encoding the ESBL to the susceptible recipient strains of enterobacteria. The frequency of transference was as high as 3.2 x 10-2 transconjugants/recipient cell when the strain of Citrobacter freundii was used as recipient. All transconjugants exhibited high level of resistance to the 3GC assayed. Conclusions: Strains of K. pneumoniae isolated from Chilean hospitals are able to disseminate the ESBL genes to clinical strains of others species of Enterobacteriaaceae.

Avaliaçäo da contaminaçäo bacteriana em desinfetantes de uso domiciliar / Evaluation of bacterial contamination in disinfectants for domestic use

Objetivo: Avaliar desinfetantes de uso domiciliar, identificando a presença de bactérias contaminantes, e conhecer o nível de tolerância dessas bactérias ao cloreto de benzalcônio. Métodos: Foram adquiridos aleatoriamente no comércio da regiäo metropolitana de Säo Paulo, SP, Brasil, 52 amostras de desinfetantes de uso domiciliar para análise quanto à presença de bactérias contaminantes. O nível de tolerância dessas bactérias ao cloreto de benzalcônio foi determinado pelo método da macrodiluiçäo em caldo. Resultados: De 52 amostras, 16 (30,77 por cento) estavam contaminadas por bactérias Gram negativas, com contagens variando entre 104 e 106 UFC/ml. Esses contaminantes foram identificados como Alcaligenes xylosoxidans, Burkholderia cepacia e Serratia marcescens. As Concentraçöes Inibitórias Mínimas (CIM: mg/ml) do cloreto de benzalcônio para S. marcescens, A. xylosoxidans e B. cepacia foram: 2,48, 1,23 e 0,30, respectivamente. Conclusöes: Os desinfetantes de uso domiciliar a base de compostos de amônio quaternário säo passíveis de contaminaçäo por bactérias. As CIMs do cloreto de benzalcônio para as bactérias contaminantes estavam abaixo das concentraçöes do princípio ativo presente nos desinfetantes, indicando que a tolerância ao biocida näo é estável, podendo ser perdida com o cultivo das bactérias em meios de cultura sem o biocida

Cadmium resistance in some members of Enterobacteriaceae.

Strains of members of Enterobacteriaceae, namely Escherichia coli (18), Klebsiella aerogenes (16), and Serratia marcescens (16) were screened for Cd resistance or sensitivity. Only one strain each of these was resistant to high levels (25 n moles/0.05 ml) CdCl2. The Minimal inhibitory concentration (MIC) of sensitive strains ranged from 0.8-5 micrograms/ml. All the resistant strains were simultaneously resistant to a number of antibiotics. Treatment with sodium dodecyl sulfate eliminated resistance to Cd and to some antibiotics.

Atividade in vitro do ciprofloxacin frente a microrganismos multirresistentes isolados de casos de infecçäo hospitalar / In vitro activity of ciprofloxacin against isolated multiresistant microorganisms of cross infection cases

Apresenta-se um estudo da atividade inibitória in vitro do ciprofloxacin, um novo derivado carboxiquinolono, frente a 240 cepas de microrganismos multirresistentes isolados de casos de infecçäo hospitalar. Foram utilizadas 42 cepas de Acinetobacter calcoaceticus, 51 de Pseudomonas aeruginosa, 49 de Serratia marcescens, 50 de Klebsiella pneumoniae e 48 de Staphylococcus aureus, as quais foram submetidas às provas de sensibilidade pela técnica da diluiçäo em ágar e da difusäo do disco em ágar. Os seguintes valores foram considerados para a interpretaçäo dos resultados: hallo <- 15mm, resistente (MIC > 2,0microng/ml); halo de 16 a 20mm, intermediário (1,0 < MIC <- 2,0 microng/ml); halo >- 21mm, sensível (MIC <- 1,0 microng/ml). Os resultados mostraram sensibilidade para 93,4% das cepas; 4,1% apresentaram resultados na faixa intermediária, 2 e 2,5% foram resistentes, sendo que, destas, maior incidência ocorreu frente a amostras de A. calcoaceticus. Conclue-se que, do ponto de vista laboratorial, o ciprofloxacin está indicado na terapêutica de infecçöes causadas por bactérias consideradas multirresistentes

Biochemical Characteristics and Antibiotic Susceptibilities of Serratia marcescens Isolated from Clinical Specimens

A minimal test scheme, consisting of deoxyribonuclease (DNase) and tween 80 hydrolysis (TEH) together with a few other biochemical tests, was used to make tentative identification of Serratia marcescens from clinical specimens. The identifications were reevaluated by testing comprehensive biochemical characteristics of 52 isolates, and all were found to be correct. The biochemical reactions of the isolates were very homogenous, showing typical characteristics of the species except in the urease test and acid production from sucrose, adonitol and inositol. These facts support the feasibility of the use of the minimal identification scheme. Pigment production was noted only in 7 isolates invalidating the value of this characteristic for the identification. Fifty-seven isolates were tested for their antibiotic susceptibility. They were found most frequently susceptible to gentamicin (47.4%), chloramphenicol (35.0%) and kanamycin (28.1%). Many isolates (49.1%) were multiply resistant to ampicillin, chloramphenicol, gentamicin, kanamycin, streptomycin and tetracycline.