Theoretical study of the interaction between the antibiotic linezolid and the active site of the 50S ribosomal subunit of the bacterium Haloarcula marismortui.

First antibiotic in the oxazolidinone class, linezolid fights gram-positive multiresistant bacteria by inhibiting protein synthesis through its interaction with the 50S subunit of the functional bacterial ribosome. For its antimicrobial action, it is necessary that its chiral carbon located in the oxazolidinone ring is in the S-conformation. Computational calculation at time-dependent density functional theory methodology, ultraviolet-visible (UV-Vis), and electronic circular dichroism spectra was obtained for noncomplexed and complexed forms of linezolid to verify the possible chirality of nitrogen atom in the acetamide group of the molecule. The molecular system has two chiral centers. So, there are now four possible configurations: RR, RS, SR, and SS. For a better understanding of the system, the electronic spectra at the PBE0/6-311++G(3df,2p) level of theory were obtained. The complexed form was obtained from the crystallographic data of the ribosome, containing the S-linezolid molecular system. The computational results obtained for the electronic properties are in good agreement with the experimental crystallographic data and available theoretical results.

Divergent Pd-catalyzed Functionalization of 4-Oxazolin-2-ones and 4-Methylene-2-oxazolidinones and Synthesis of Heterocyclic-Fused Indoles.

Palladium-catalyzed functionalization was presently performed on two building blocks: 4-oxazolin-2-ones and 4-methylene-2-oxazolidinones. Direct Heck arylation of 4-oxazolin-2-ones led to a series of 5-aryl-4-oxazolin-2-ones, including analogues with N-chiral auxiliary, in an almost quantitative yield. The Pd(II)-catalyzed homocoupling reaction of 4-oxazolin-2-ones provided novel heterocyclic across-ring dienes. Meanwhile, the intramolecular cross-coupling of N-aryl-4-methylene-2-oxazolidinones furnished a series of oxazolo[3,4-a]indol-3-ones. Further functionalization of 4-methylene-2-oxazolidinones afforded substituted indoles and heterocyclic-fused indoles with aryl, bromo, carbinol, formyl, and vinyl groups. A computational study was carried out to account for the behavior of the formylated derivatives. The currently developed methodology was applied to a new formal total synthesis of ellipticine.

Antimicrobial Susceptibility Testing for Enterococci.

Enterococci are major, recalcitrant nosocomial pathogens with a wide repertoire of intrinsic and acquired resistance determinants and the potential of developing resistance to all clinically available antimicrobials. As such, multidrug-resistant enterococci are considered a serious public health threat. Due to limited treatment options and rapid emergence of resistance to all novel agents, the clinical microbiology laboratory plays a critical role in deploying accurate, reproducible, and feasible antimicrobial susceptibility testing methods to guide appropriate treatment of patients with deep-seated enterococcal infections. In this review, we provide an overview of the advantages and disadvantages of existing manual and automated methods that test susceptibility of Enterococcus faecium and Enterococcus faecalis to ß-lactams, aminoglycosides, vancomycin, lipoglycopeptides, oxazolidinones, novel tetracycline-derivatives, and daptomycin. We also identify unique problems and gaps with the performance and clinical utility of antimicrobial susceptibility testing for enterococci, provide recommendations for clinical laboratories to circumvent select problems, and address potential future innovations that can bridge major gaps in susceptibility testing.

Coexistence of the Oxazolidinone Resistance-Associated Genes cfr and optrA in Enterococcus faecalis From a Healthy Piglet in Brazil.

Oxazolidinones are one of the most important antimicrobials potentially active against glycopeptide- and ß-lactam-resistant Gram-positive pathogens. Linezolid-the first oxazolidinone to be approved for clinical use in 2000 by the US Food and Drug Administration-and the newer molecule in the class, tedizolid, inhibit protein synthesis by suppressing the formation of the 70S ribosomal complex in bacteria. Over the past two decades, transferable oxazolidinone resistance genes, in particular cfr and optrA, have been identified in Firmicutes isolated from healthcare-related infections, livestock, and the environment. Our goals in this study were to investigate the genetic contexts and the transferability of the cfr and optrA genes and examine genomic features, such as antimicrobial resistance genes, plasmid incompatibility types, and CRISPR-Cas defenses of a linezolid-resistant Enterococcus faecalis isolated in feces from a healthy pig during an antimicrobial surveillance program for animal production in Brazil. The cfr gene was found to be integrated into a transposon-like structure of 7,759 nt flanked by IS1216E and capable of excising and circularizing, distinguishing it from known genetic contexts for cfr in Enterococcus spp., while optrA was inserted into an Inc18 broad host-range plasmid of >58 kb. Conjugal transfer of cfr and optrA was shown by filter mating. The coexistence of cfr and optrA in an E. faecalis isolated from a healthy nursery pig highlights the need for monitoring the use of antibiotics in the Brazilian swine production system for controlling spread and proliferation of antibiotic resistance.

Tedizolid (torezolid) for the treatment of complicated skin and skin structure infections.

INTRODUCTION: Acute bacterial skin and skin structure infections (ABSSSI) are among the most frequent infectious diseases. Recently, several new antibiotics with activity against MRSA have been approved. Tedizolid, a second-generation oxazolidinone approved for ABSSSI offers theoretical advantages over first-generation oxazolidinones. AREAS COVERED: A comprehensive online search of Medline, ClinicalTrials.gov, and conference presentations was made, selecting articles between January 2000 and April 2020. In this review, the authors discuss the chemical and microbiological properties of tedizolid, summarize its efficacy, safety, and potential role in the treatment of ABSSSI as well as the potential for future indications. EXPERT OPINION: Tedizolid has proven to be non-inferior compared to linezolid for the treatment of ABSSSI in two registrational phase III clinical trials, being well tolerated. Tedizolid exhibits antibacterial activity against the most important ABSSSI pathogens (including multidrug-resistant strains of MRSA), as well as mycobacteria and Nocardia. It appears to have a safe profile, including decreased myelotoxicity and no significant drug interactions. Preliminary studies with longer duration of therapy seem to confirm these potential benefits. Overall, tedizolid expands the newly acquired armamentarium to treat ABSSSI. The role of tedizolid for other indications is under investigation and has yet to be determined.

Morphoanatomical injuries in Pistia stratiotes L. (Araceae) as a result of exposure to clomazone in water.

Contamination of water sources due to herbicide is of great concern. Clomazone is a pesticide with a high contamination potential which could possibility lixiviate to water streams. Changes caused by residual herbicide include flora modifications which are generally detrimental for some species. The lack of morphological studies performed in aquatic plants exposed to herbicide-contaminated environments has encouraged the development of our research. For the first time, we present a study that aimed to evaluate leaf injuries visible to the naked eye as well as microscopical effects which may be caused by clomazone on Pistia stratiotes. Pistia stratiotes was subjected to five concentrations of clomazone. Our analysis showed leaf injuries, especially after 15 days of clomazone application. Hormesis was observed when the water lettuce was subjected to the lower concentrations. Total leaf area showed increase following by reduction while injured until reaching the highest concentration. Although the concentrations of clomazone tested in our study are not lethal to water lettuce, such herbicide have still caused morphoanatomical damages on leaves which advocates for the use of P. stratiotes as a bioindicator of the presence of herbicides such as clomazone in water.

Transferable Resistance Gene optrA in Enterococcus faecalis from Swine in Brazil.

OptrA is an ATP-binding cassette (ABC)-F protein that confers resistance to oxazolidinones and phenicols and can be either plasmid-encoded or chromosomally encoded. Here, we isolated 13 Enterococcus faecalis strains possessing a linezolid MIC of ≥4 mg/liter from nursery pigs in swine herds located across Brazil. Genome sequence comparison showed that these strains possess optrA in different genetic contexts occurring in 5 different E. faecalis sequence type backgrounds. The optrA gene invariably occurred in association with an araC regulator and a gene encoding a hypothetical protein. In some contexts, this genetic island was able to excise and form a covalently closed circle within the cell; this circle appeared to occur in high abundance and to be transmissible by coresident plasmids.

Phytoremediation by Eremanthus crotonoides and Inga striata decay atrazine and clomazone residues in the soil.

The atrazine and clomazone molecules have potential to contaminate environments, especially water resources. Phytoremediation decontamination can prevent or reduce the quantity of these products reaching watercourses. The objective was to evaluate the remedial potential and the physiological sensitivity of Eremanthus crotonoides (DC.) Sch. Bip and Inga striata Benth to atrazine and clomazone in soils contaminated with 0.0, 0.5, 1.0 and 2.0 times the recommended commercial dose of these herbicides. The photosynthesis, CO2 consumed stomatal conductance and transpiration of E. crotonoides and I. striata, in soils contaminated with atrazine and clomazone, were evaluated. The herbicide residues were detected by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) 30 days after the last herbicide application. The photosynthesis rate and CO2 consumed by E. crotonoides and I. striata were lower in soils contaminated by atrazine and clomazone. Inga striata had lower stomatal conductance and transpiration in soil contaminated with clomazone. Eremanyhus crotonoides and I. striata reduced the residues of these herbicides. The atrazine and clomazone reduced the physiological variables of E. crotonoides and I. striata. These plants can be used to recover areas with residues of these herbicides, acting as filters that will decrease the amount of herbicides that would reach the watercourses.

Use of Pistia stratiotes for phytoremediation of water resources contaminated by clomazone.

The Pistia stratiotes L. was tested for phytoremediation potential of the compound clomazone in water. Clomazone is a post-emergent herbicide marketed as Gamit®. Five groups with four samples each were evaluated, a low concentration control (LCC: 37.86 mg L-1), low concentration treatment (LCT: 38.16 mg L-1), high concentration control (HCC: 54.71 mg L-1), high concentration treatment (HCT: 54.33 mg L-1), and a plant control group (PCG). Plant resistance to clomazone at determined concentrations and their ability to remove the herbicide from water by HPLC over 24 days were evaluated. The results demonstrate that P. stratiotes has high resistance to clomazone exposure and was able to eliminate up to 90% of the herbicide residues during the experimental period. Under dissipation by P. stratiotes in water, clomazone had a halflife of 19.6 days for in the control treatments, LCC and HCC, and 8.0 days in the treatment groups, LCT and HCT. This study indicates that Pistia stratiotes is an effective phytoremediation agent for the herbicide clomazone in water.

Impact of percentage and particle size of sugarcane biochar on the sorption behavior of clomazone in Red Latosol.

Biochar is a carbonaceous material that has excellent potential as a fertilizer and soil conditioner. However, there is a lack of information concerning the effects of the amount and particle size of this pyrogenic material on the soil sorption capacity. In this work, evaluation was made of changes in clomazone (CMZ) sorption in a Red Latosol following soil conditioning using different percentages (0.25, 0.5, and 1% w/w) of sugarcane biochar in three particle sizes (<106, 106-508, and 508-610 µm). The conditioned soils presented apparent sorption coefficients (Kd) up to 1300 times higher than that of pure soil, besides changes in the behavior of CMZ sorption. The biochar particle size and percentage influenced sorption of the herbicide as well as its retention in the amended soil during desorption processes. Both sorption and desorption Freundlich constants were linearly correlated with the external surface area of the biochar present in the soil.

Actividad in vitro del tedizolid y de antibióticos de comparación en aislamientos de Staphylococcus aureus resistentes a meticilina en infecciones de piel y tejidos blandos en siete hospitales de Colombia / In vitro activity of tedizolid and other comparator drugs in methicillin-resistant Staphylococcus aureus isolates in skin and soft tissue infections in seven Colombian hospitals

Introducción. Staphylococcus aureus resistente a meticilina (SARM) causa infecciones graves de la piel y los tejidos blandos en los hospitales y, en los últimos años, en la comunidad. El tedizolid es una nueva oxazolidinona cuya potencia in vitro ha demostrado ser mayor que la del linezolid frente a este microorganismo. Objetivo. Conocer la actividad antimicrobiana del tedizolid y de algunos antibióticos de comparación en aislamientos de SARM causante de infecciones de piel y tejidos blandos en hospitales de Colombia. Materiales y métodos. Se hizo un estudio multicéntrico prospectivo y descriptivo a lo largo de doce meses en siete hospitales de tercer nivel de Colombia. Se recolectaron aislamientos de SARM de pacientes adultos con infección de piel y tejidos blandos. Se determinó la concentración inhibitoria mínima (CIM) mediante la técnica de ETEST® (bioMérieux) del tedizolid, el linezolid, la vancomicina, la daptomicina, el trimetoprim-sulfametoxazol y la clindamicina. Resultados. Se obtuvieron aislamientos de SARM de 102 pacientes, de los cuales 56 (54,9 %) eran hombres; el promedio de edad fue de 46,8 años. La infección tuvo origen en la comunidad en 77 casos (75,4 %). El tipo de muestra que predominó fue el absceso (69 pacientes: 67,6 %). Todos los aislamientos fueron sensibles a tedizolid, linezolid, daptomicina, trimetoprim-sulfametoxazol y vancomicina. La actividad in vitro del tedizolid fue mayor que la del linezolid. Los intervalos de la CIM del tedizolid oscilaron entre 0,125 µg/ml y 0,5 µg/ml en tanto que los del linezolid fluctuaron entre 1 µg/m y 2 µg/ml. Conclusiones. Las cepas circulantes de SARM en Colombia presentaron una gran sensibilidad al tedizolid, por lo cual sería una alternativa terapéutica para las infecciones de piel y tejidos blandos en nuestro medio.

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe skin and soft tissue infections in hospitals and, more recently, in the community. Tedizolid is a new second-generation oxazolidinone derivative having greater in vitro potency than linezolid against this type of microorganism. Objectives: To evaluate the antimicrobial activity of tedizolid and other comparator antibiotics in MRSA isolates causing skin and soft tissue infections in Colombian hospitals. Materials and methods: We conducted a prospective, multi-center descriptive study in seven tertiary-level hospitals in Colombia along a 12-month period. MRSA isolates were collected from adult patients with skin and soft tissue infections. Tedizolid, linezolid, vancomycin, daptomycin, trimethoprimsulfamethoxazole, and clindamycin minimum inhibitory concentration (MIC) was determined by ETEST® (bioMérieux). Results: MRSA isolates were obtained from 102 patients with an average age of 46.8 years of whom 56 (54.9%) were men. Infection was community-acquired in 77 cases (75.4%). Abscess-related samples predominated (69 patients: 67.6%). All isolates were susceptible to tedizolid, linezolid, daptomycin, trimethoprim-sulfamethoxazole, and vancomycin. Tedizolid had greater in vitro activity than linezolid. Tedizolid MIC intervals ranged from 0.125 µg/mL to 0.5 µg/mL while those of linezolid ranged from 1µg/mL to 2µg/mL. Conclusions: MRSA strains circulating in Colombia are highly susceptible to tedizolid and can be considered a therapeutic alternative for hospitals and/or community-acquired skin and soft tissue infections.

Daptomycin and vancomycin heteroresistance revealed among CC5-SCCmecII MRSA clone and in vitro evaluation of treatment alternatives.

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to the success of clinical treatment. Besides high antimicrobial resistance rates, the presence of heterogeneous vancomycin-intermediate S. aureus (hVISA) and heterogeneous daptomycin-non-susceptible S. aureus (hDNSSA) in the hospital environment is underestimated and is associated with treatment failure. The aim of this study was to investigate MRSA dissemination in a Brazilian hospital and to evaluate the efficacy of various treatment options in vitro. METHODS: MRSA strains were typed by MLST, PFGE and SCCmec typing. Minimum inhibitory concentrations (MICs) to daptomycin, linezolid, quinupristin/dalfopristin, teicoplanin, tetracycline, tigecycline, vancomycin and tedizolid were determined by broth microdilution. The presence of a heterogeneous population was detected by population analysis profile (PAP). Regarding hVISA and hDNSSA strains, the sequences and expression levels of genes involved in resistance to daptomycin and vancomycin were determined as well as cell wall thickness and autolysis. RESULTS: ST5/ST105-SCCmecII lineage was prevalent amongst 27 clinical MRSA characterised in this study. Two hDNSSA strains (one also hVISA) were detected and were confirmed by PAP. Isolate SCMSC29 (hVISA and hDNSSA) showed increased expression of genes involved in cell wall metabolism, slight cell wall thickening, reduction of autolysis, and single nucleotide polymorphisms (SNPs) in the rpoB and mprF genes compared with the susceptible strain SCMSC31. SCMSC35 (hDNSSA) presented SNPs in the rpoB and mprF genes as well as a thickened cell wall. CONCLUSIONS: Despite this worrying and hard to detect phenotype, treatment alternatives such as teicoplanin, linezolid, tetracycline, tigecycline, quinupristin/dalfopristin and tedizolid were all active against these isolates.

Responses of macroinvertebrate communities to pesticide application in irrigated rice fields.

The ability to recover to original states after disturbances makes macroinvertebrates useful tools for assessing the impacts of pesticides. Many studies showed that direct exposure to pesticides decreases macroinvertebrate richness and alters their composition. The main objective of this study was to assess recovery patterns in macroinvertebrate communities after pesticide application in irrigated rice fields. We analyzed short-term temporal dynamics of macroinvertebrate communities after application of the herbicides bispyribac-sodium and clomazone and the insecticide chlorantraniliprole, over the rice-growing season in southern Brazil. We selected three conventional rice fields and the recovery of macroinvertebrate communities was also compared with three adjacent natural ponds. The study was developed from November 2011 to February 2012 (rice-growing season). Five macroinvertebrate collections were carried out 3, 7, 14, 38, and 60 days after pesticide application (November 25). Rice fields showed lower richness and abundance than ponds in the period immediately after pesticide application, and recovery rates in the richness of macroinvertebrate communities were more conspicuous as pesticide residuals dissipated from the fields. Macroinvertebrate community structure in rice fields also became more similar to natural ponds as pesticide traces were scarcer. However, macroinvertebrate abundance patterns were not related to pesticide concentrations in the fields. Our results supported the general hypothesis on the negative effects of pesticide application on macroinvertebrate community in irrigated rice fields, although other environmental features (e.g., length of the flooded period) also contributed to explain temporal dynamics in the macroinvertebrate communities from irrigated rice fields.

In vitro activity of tedizolid and other comparator drugs in methicillin-resistant Staphylococcus aureus isolates in skin and soft tissue infections in seven Colombian hospitals / Actividad in vitro del tedizolid y de antibióticos de comparación en aislamientos de Staphylococcus aureus resistentes a meticilina en infecciones de piel y tejidos blandos en siete hospitales de Colombia.

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe skin and soft tissue infections in hospitals and, more recently, in the community. Tedizolid is a new second-generation oxazolidinone derivative having greater in vitro potency than linezolid against this type of microorganism. Objectives: To evaluate the antimicrobial activity of tedizolid and other comparator antibiotics in MRSA isolates causing skin and soft tissue infections in Colombian hospitals. Materials and methods: We conducted a prospective, multi-center descriptive study in seven tertiary-level hospitals in Colombia along a 12-month period. MRSA isolates were collected from adult patients with skin and soft tissue infections. Tedizolid, linezolid, vancomycin, daptomycin, trimethoprim-sulfamethoxazole, and clindamycin minimum inhibitory concentration (MIC) was determined by ETEST® (bioMérieux). Results: MRSA isolates were obtained from 102 patients with an average age of 46.8 years of whom 56 (54.9%) were men. Infection was community-acquired in 77 cases (75.4%). Abscess-related samples predominated (69 patients: 67.6%). All isolates were susceptible to tedizolid, linezolid, daptomycin, trimethoprim-sulfamethoxazole, and vancomycin. Tedizolid had greater in vitro activity than linezolid. Tedizolid MIC intervals ranged from 0.125 µg/mL to 0.5 µg/mL while those of linezolid ranged from 1µg/mL to 2µg/mL. Conclusions: MRSA strains circulating in Colombia are highly susceptible to tedizolid and can be considered a therapeutic alternative for hospitals and/or community-acquired skin and soft tissue infections.

Introducción. Staphylococcus aureus resistente a meticilina (SARM) causa infecciones graves de la piel y los tejidos blandos en los hospitales y, en los últimos años, en la comunidad. El tedizolid es una nueva oxazolidinona cuya potencia in vitro ha demostrado ser mayor que la del linezolid frente a este microorganismo.Objetivo. Conocer la actividad antimicrobiana del tedizolid y de algunos antibióticos de comparación en aislamientos de SARM causante de infecciones de piel y tejidos blandos en hospitales de Colombia.Materiales y métodos. Se hizo un estudio multicéntrico prospectivo y descriptivo a lo largo de doce meses en siete hospitales de tercer nivel de Colombia. Se recolectaron aislamientos de SARM de pacientes adultos con infección de piel y tejidos blandos. Se determinó la concentración inhibitoria mínima (CIM) mediante la técnica de ETEST® (bioMérieux) del tedizolid, el linezolid, la vancomicina, la daptomicina, el trimetoprim-sulfametoxazol y la clindamicina.Resultados. Se obtuvieron aislamientos de SARM de 102 pacientes, de los cuales 56 (54,9 %) eran hombres; el promedio de edad fue de 46,8 años. La infección tuvo origen en la comunidad en 77 casos (75,4 %). El tipo de muestra que predominó fue el absceso (69 pacientes: 67,6 %). Todos los aislamientos fueron sensibles a tedizolid, linezolid, daptomicina, trimetoprim-sulfametoxazol y vancomicina. La actividad in vitro del tedizolid fue mayor que la del linezolid. Los intervalos de la CIM del tedizolid oscilaron entre 0,125 µg/ml y 0,5 µg/ml en tanto que los del linezolid fluctuaron entre 1 µg/m y 2 µg/ml.Conclusiones. Las cepas circulantes de SARM en Colombia presentaron una gran sensibilidad al tedizolid, por lo cual sería una alternativa terapéutica para las infecciones de piel y tejidos blandos en nuestro medio.

Removal of clomazone herbicide from a synthetic effluent by electrocoagulation.

The aim of this work was to investigate the kinetics of removal of clomazone herbicide from an aqueous solution by electrocoagulation. The experiments were performed in a cylindrical batch reactor with six aluminum electrodes in monopolar mode, arranged in series and connected to a digital DC power. The aqueous solution (tap water + clomazone) with initial pH close to 7.9 was always treated at ambient temperature (≈20 °C) and atmospheric pressure for 5,400 s. For a confidence level of 95% the rate constant of electrocoagulation and the efficiency of removal of clomazone at equilibrium were 2.1 × 10(-3) ± 0.5 × 10(-3) s(-1) and 97.7 ± 2.2%, respectively. The final chemical oxygen demand was 88% lower than that measured initially, while turbidity and apparent color were totally removed from the synthetic solution at a rate close to that of formation of aluminum hydroxides. Some reaction intermediates, such as benzonitrile-2-chloro and 2-chloro-hex-2,4-diene-1,6-dioic-acid determined by gas chromatography mass spectrometry (GC-MS) analysis, explain the ratio of equilibrium to initial total organic carbon approximately between 0.6 and 0.8 at a probability of 95%.

The controversy over the use of cholesteryl ester transfer protein inhibitors: is there some light at the end of the tunnel?

BACKGROUND: According to epidemiological studies, there is no clear relationship between the plasma cholesteryl ester transfer protein (CETP) concentration and the development of atherosclerosis in human populations. Although some studies suggest that increased CETP activity relates to undesirable profiles of plasma lipoproteins, promoting an anti-atherogenic plasma lipoprotein profile by drugs that inhibit CETP has not succeeded in preventing atherosclerosis in humans. MATERIALS AND METHODS: This review describes 28 investigations in human populations dealing with plasma CETP, 11 in mice that express human CETP and seven in animals (six in rabbits and one in mice) in which plasma CETP activity was inhibited by drugs. RESULTS: Present review shows that models in mice expressing human CETP are not illuminating because they report increase as well reduction of atherosclerosis. However, investigations in rabbits and mice that develop severe hypercholesterolaemia clearly indicate that impairment of the plasma CETP activity elicits protection against the development of atherosclerosis; in all of these experiments are attained substantial reductions of the atherogenic lipoproteins, namely, plasma apoB containing lipoproteins. CONCLUSION: These models are strong indicators that the benefit in preventing atherosclerosis should be earned in cases of hyperlipidemia by CETP inhibitors.

Onychomatricoma: a tumor unknown to dermatologists

A sixty-one year old white female was referred to the Dermatology Department to treat an ingrown nail in the inner corner of the left hallux. Examination of the entire nail unit showed the presence of xanthonychia in the outer corner besides thickening and increase in the transverse curvature of the nail plate. Dermoscopy and nuclear magnetic resonance of the free edge of the nail plate detected characteristic signs of onychomatricoma, a diagnosis that was later confirmed by anatomopathological exam.

Integrated assessment of biomarker response in carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) exposed to clomazone.

Clomazone is considered a potential contaminant of groundwater and is persistent in the environment. To verify the effects of clomazone in Cyprinus carpio and Rhamdia quelen, a method that combines biomarker responses into an index of "integrated biomarker response" (IBR) was used for observed biological alterations in these species. Thiobarbituric acid-reactive substances in liver of carp and silver catfish decreased at both concentrations tested. However, in muscle it increased in carp at 3 mg/L and silver catfish at 6 mg/L. Protein carbonyl increased in liver (3 and 6 mg/L) and muscle (6 mg/L) of carp. In carp, superoxide dismutase (SOD) increased at 3 mg/L and catalase at 6 mg/L. In silver catfish, SOD in liver decreased at 3 mg/L. Glutathione-S-transferase increased at 3 mg/L in muscle of carp. Nonprotein thiol levels decreased at both concentrations in liver of silver catfish and muscle of carp. In silver catfish, acetylcholinesterase (AChE) decreased in brain at 6 mg/L. Nevertheless, AChE in muscle of both species increased at 3 and 6 mg/L. IBR was standardized scores of biomarker responses and was visualized using star plots. The IBR values shown that in carp there was predominantly an induction of parameters, whereas in silver catfish there was inhibition of these responses. In this way, IBR may be a practical tool for the identification of biological alterations in fish exposed to pesticides. In the present study, IBR was efficient for comparisons of fish species using clomazone. This study may serve as a base for evaluation of other pesticides in the rice field, environment, or laboratory experiment.

In vitro susceptibility to methicillin, vancomycin and linezolid of staphylococci isolated from bloodstream infections in eastern Turkey.

Staphylococcus species are one of the major causes of bacterial bloodstream infections. Multi-resistant staphylococci infections are major therapeutic problems. This study was aimed to detect methicillin, linezolid and vancomycin susceptibilities of Staphylococcus isolates. A total of 870 Staphylococcus strains isolated from blood cultures of hospitalized patients with BSI. Antimicrobial susceptibilities of methicillin, linezolid and vancomycin were detected according to the Clinical and Laboratory Standards Institute (CLSI). A total of 771 (88.6%) isolates were coagulase-negative staphylococci (CoNS). 700 (80.5%) isolates were methicillin-resistant (MR) and 170 (19.5%) were methicillin-susceptible (MS). All the MS isolates were also susceptible to linezolid. However 15 (1.7%) of MR strains were resistant to linezolid. The minimum inhibitory concentration range for the linezolid-resistant isolates by Etest was 6-32 µg/mL. The difference between linezolid susceptibilities for MS and MR staphylococci was not quite statistically significant (p = 0.052). There was no statistically significant difference between S. aureus and CoNS isolates for linezolid susceptibility. All of the isolates were susceptible to vancomycin. In conclusion, linezolid is currently an efficient option for the treatment of methicillin-resistant staphylococci infections.

Differential responses of the antioxidant system of ametryn and clomazone tolerant bacteria.

The herbicides ametryn and clomazone are widely used in sugarcane cultivation, and following microbial degradation are considered as soil and water contaminants. The exposure of microorganisms to pesticides can result in oxidative damage due to an increase in the production of reactive oxygen species (ROS). This study investigated the response of the antioxidant systems of two bacterial strains tolerant to the herbicides ametryn and clomazone. Bacteria were isolated from soil with a long history of ametryn and clomazone application. Comparative analyses based on 16S rRNA gene sequences revealed that strain CC07 is phylogenetically related to Pseudomonas aeruginosa and strain 4C07 to P. fulva. The two bacterial strains were grown for 14 h in the presence of separate and combined herbicides. Lipid peroxidation, reduced glutathione content (GSH) and antioxidant enzymes activities were evaluated. The overall results indicated that strain 4C07 formed an efficient mechanism to maintain the cellular redox balance by producing reactive oxygen species (ROS) and subsequently scavenging ROS in the presence of the herbicides. The growth of bacterium strain 4C07 was inhibited in the presence of clomazone alone, or in combination with ametryn, but increased glutathione reductase (GR) and glutathione S-transferase (GST) activities, and a higher GSH concentration were detected. Meanwhile, reduced superoxide dismutase (SOD), catalase (CAT) and GST activities and a lower concentration of GSH were detected in the bacterium strain CC07, which was able to achieve better growth in the presence of the herbicides. The results suggest that the two bacterial strains tolerate the ametryn and clomazone herbicides with distinctly different responses of the antioxidant systems.