24 research outputs found
Ruling Out Bacillus anthracis
Optimization of methods for ruling out Bacillus anthracis leads to increased yields, faster turnaround times, and a lighter workload. We used 72 environmental nonâB. anthracis bacilli to validate methods for ruling out B. anthracis. Most effective were horse blood agar, motility testing after a 2-h incubation in trypticase soy broth, and screening with a B. anthracisâselective agar
Adaptation of Brucella melitensis Antimicrobial Susceptibility Testing to the ISO 20776 Standard and Validation of the Method
This article belongs to the Special Issue Emerging Themes in Brucella and Brucellosis.Brucellosis, mainly caused by Brucella (B.) melitensis, is associated with a risk of chronification
and relapses. Antimicrobial susceptibility testing (AST) standards for B. melitensis are not
available, and the agent is not yet listed in the EUCAST breakpoint tables. CLSI recommendations
for B. melitensis exist, but they do not fulfill the requirements of the ISO 20776 standard regarding
the culture medium and the incubation conditions. Under the third EU Health Programme, laboratories
specializing in the diagnostics of highly pathogenic bacteria in their respective countries
formed a working group within a Joint Action aiming to develop a suitable method for the AST of B. melitensis. Under the supervision of EUCAST representatives, this working group adapted the
CLSI M45 document to the ISO 20776 standard after testing and validation. These adaptations included
the comparison of various culture media, culture conditions and AST methods. A Standard
Operation Procedure was derived and an interlaboratory validation was performed in order to evaluate
the method. The results showed pros and cons for both of the two methods but also indicate
that it is not necessary to abandon MuellerâHinton without additives for the AST of B. melitensis.This research was funded by the EU Health Programme 2014â2020, through the Consumers, Health, Agriculture and Food Executive Agency (CHAFEA, European Commission), the Joint
Action EMERGE (CHAFEA n° 677 066) and the Joint Action SHARP (848096-SHARP JA).info:eu-repo/semantics/publishedVersio
Characterization of <i>Lacticaseibacillus rhamnosus</i>, <i>Levilactobacillus brevis</i> and <i>Lactiplantibacillus plantarum</i> Metabolites and Evaluation of Their Antimicrobial Activity against Food Pathogens
Lactic acid bacteria (LAB) play an important role as natural food preservatives. However, the characterization of the variety of their metabolites is limited. The objective of this study was to determine the production of specific metabolites of Lacticaseibacillus rhamnosus, Levilactobacillus brevis and Lactiplantibacillus plantarum by an optimized liquid chromatography with an ultraviolet/diode detection (HPLC-UV/DAD) method and to investigate their potential antimicrobial activity against specific food pathogens. Based on the results of this study, the main metabolites detected in Levilactobacillus brevis were 103.4 ÎŒg mLâ1 DL-p-Hydroxyphenyllactic acid (OH-PLA) and 2.59 ÎŒg mLâ1 vanillic acid, while 216.2 ÎŒg mLâ1 OH-PLA, 19.0 ÎŒg mLâ1 salicylic acid, 3.7 ÎŒg mLâ1 vanillic acid, 6.9 ÎŒg mLâ1 ferulic acid, 4.2 ÎŒg mLâ1 benzoic acid and 1.4 ÎŒg mLâ1 4-Hydrocinnamic acid were identified in the Lactiplantibacillus plantarum strain and 147.6 ÎŒg mLâ1 OH-PLA and 4.9 ÎŒg mLâ1 ferulic acid were identified in Lacticaseibacillus rhamnosus. This study provides alternative approaches for the molecules involved in the antimicrobial activity of food microorganism fermentation. These molecules may be used as antimicrobial ingredients in the food industry instead of conventional chemical preservatives
Differences in the evolution of imipenem susceptibility among Klebsiella pneumoniae and Escherichia coli isolates during a 6-year period in a tertiary care hospital
The evolution of imipenem disk-diffusion susceptibility results of 2652
strains of Klebsiella pneumoniae and 7596 Escherichia coli isolated
during the period 2000-2005 were analysed. Screening for production of
metallo-beta-lactamases was performed using the EDTA-synergy method. The
percentage rate of K. pneumoniae isolates having a zone diameter <= 25
mm increased from 20% in 2000 to 41% in 2005, whereas the respective
rate of isolates having a zone diameter >= 30 mm decreased from 48 to
23%. These changes were more evident during 2000-2002, followed in 2003
by the isolation of the first imipenem-resistant strains. Regarding E.
coli, a similar decrease was observed (the rates of isolates having a
zone diameter <= 25 mm and >= 30 mm changed from 7% and 68% in 2000,
to 32% and 36% in 2005, respectively) following the respective changes
of K. pneumoniae. A total of 20 K. pneumoniae strains, but no E. coli,
were confirmed as metalto-beta-lactamase producers. In conclusion, a
decrease of the imipenem susceptibility prior to the isolation of the
first resistant strains in a tertiary care hospital was detected, as
well as differences in this decrease between the two species. These
findings indicate that monitoring of the evolution of imipenem
susceptibility in real-time may help in unveiling forthcoming resistance
and in implementing the appropriate diagnostic techniques. (c) 2006
Elsevier B.V. and the International Society of Chemotherapy. All rights
reserved
Effect of Low-Level Laser Irradiation (810 nm) on the Proliferation and Differentiation of Osteoblast-Like Cells Cultured on SLA Titanium Discs Exposed to a Peri-implantitis Environment: Effect of LLLT on osteoblast-like cells exposed to a peri-implantitis environment
Introduction: Elimination of inflammation and re-osseointegration are the major objectives of peri-implantitis therapy. Existing data, however, do not support any decontamination approach. Thus, the present in vitro study aims to assess whether the air-debriding decontamination method with erythritol powder restores the biocompatibility of infected titanium discs and to investigate the potent biomodulatory ability of diode laser (810 nm) irradiation to promote cell proliferation and differentiation of premature osteoblast-like cells (MG63) towards osteocytes.Methods: The experimental groups consisted of cells seeded on titanium discs exposed or not in a peri-implantitis environment with or without biomodulation. Infected discs were cleaned with airflow with erythritol powder. Cell cultures seeded on tricalcium phosphate (TCP) surfaces with or without biomodulation with a laser (810 nm) were used as controls. The study evaluated cell viability, proliferation, adhesion (SEM) at 24, 48 and 72 hours, and surface roughness changes (profilometry), as well as the effects of low-level laser therapy (LLLT) on ALP, OSC, TGF-b1, Runx2, and BMP-7 expression in MG63 cellsâ genetic profile on days 7, 14, and 21.Results: The MTT assay as well as the FDA/PI method revealed that cell proliferation did not show significant differences between sterile and decontaminated discs at any time point. SEM photographs on day 7 showed that osteoblast-like cells adhered to both sterile and disinfected surfaces, while surface roughness did not change based on amplitude parameters. The combination of airflow and LLLT revealed a biomodulated effect on the differentiation of osteoblast-like cells about the impact of laser irradiation on the genetic profile of the MG63 cells.Conclusion: In all groups tested, osteoblast-like cells were able to colonize, proliferate, and differentiate, suggesting a restoration of biocompatibility of infected discs using airflow. Furthermore, photomodulation may promote the differentiation of osteoblast-like cells cultured on both sterile and disinfected titanium surfaces
Molecular Evidence of a Broad Range of Pathogenic Bacteria in Ctenocephalides spp.: Should We Re-Examine the Role of Fleas in the Transmission of Pathogens?
The internal microbiome of common cat and dog fleas was studied for DNA evidence of pathogenic bacteria. Fleas were grouped in pools by parasitized animal. DNA was extracted and investigated with 16S metagenomics for medically relevant (MR) bacteria, based on the definitions of the International Statistical Classification of Diseases and Related Health Problems (WHO). The MR bacterial species totaled 40, were found in 60% of flea-pools (N = 100), and included Acinetobacterbaumannii, Bacteroidesfragilis, Clostridiumperfringens, Enterococcusfaecalis, E. mundtii, Fusobacteriumnucleatum, Haemophilusaegyptius, Kingellakingae, Klebsiellapneumoniae, Leptotrichiabuccalis, L. hofstadii, Moraxellalacunata, Pasteurellamultocida, Propionibacteriumacnes, P. propionicum, Proteusmirabilis, Pseudomonasaeruginosa, Rickettsiaaustralis, R. hoogstraalii, Salmonellaenterica, and various Bartonella, Staphylococcus, and Streptococcus species. B. henselae (p = 0.004) and B. clarridgeiae (p = 0.006) occurred more frequently in fleas from cats, whereas Rickettsiahoogstraalii (p = 0.031) and Propionibacteriumacnes (p = 0.029) had a preference in fleas from stray animals. Most of the discovered MR species can form biofilm, and human exposure may theoretically occur through the flea-host interface. The fitness of these pathogenic bacteria to cause infection and the potential role of fleas in the transmission of a broad range of diseases should be further investigated
Address for correspondence:
In the present study, antibiotic resistance data generated in Greece by the WHONET Network were further analyzed by the use of data mining techniques. More specifically association rules were extracted among data collected in the Microbiology Dept. of âSismanoglion â General Hospital, a 500-bed general hospital, in Athens, Greece. The data studied were the susceptibility results, as well as data concerning the patientâs wards, the day of isolation and the type of clinical specimen, of a total of 20,794 bacterial isolates collected in the period January 1 st 1996 to December 31 st 2000,. The factors used to measure the importance of each association rule were its strength (confidence), its support, its coverage, its leverage and its lift. Two main rule categories were generated, one associating clinical specimen, time and ward of isolation, with bacterial species and the second one associating the same attributes with resistant phenotypes. The factors most often used to compare and evaluate different rules were leverage and lift. The system generated association rules in an unsupervised automatic way and revealed pieces of knowledge not easily available with standard supervised procedures of analysis, thus making it very useful in an automated public health surveillance system.