UhpTE350Q mutation along with the presence of fosA6/5 genes in the genome probably contributes to inherent fosfomycin resistance of Klebsiella pneumoniae / 南方医科大学学报

OBJECTIVE@#To investigate the molecular mechanism underlying inherent fosfomycin resistance of Klebsiella pneumoniae (K. pneumoniae).@*METHODS@#The draft genomic sequences of 14 clinical hypervirulent/hypermucoviscous K. pneumoniae (HvKP/ HmKP) isolates were obtained using the next-generation sequencing technology. The genomic sequences were analyzed using the Resistance Gene Identifier (RGI) software for predicting the resistome based on homology and SNP models in the Comprehensive Antibiotic Resistance Database (CARD) and for identification of the presence of phosphomycin resistancerelated genes uhpt and fosA and their mutations in the bacterial genomes. The results were verified by analyzing a total of 521 full-length genomic sequences of K. pneumonia strains obtained from GenBank.@*RESULTS@#All the 14 clinical isolates of HvKP/ HmKP carried hexose phosphate transporter (UhpT) gene mutation, in which the glutamic acid was mutated to glutamine at 350aa (UhpTE350Q mutation); the presence of fosA6 gene was detected in 12 (85.71%) of the isolates and fosA5 gene was detected in the other 2 (14.29%) isolates. Analysis of the genomic sequences of 521 K. pneumonia strains from GenBank showed that 508 (97.50%) strains carried UhpTE350Q mutation, 439 (84.26%) strains harbored fosA6, and 80 (15.36%) strains harbored fosA5; 507 (97.31%) strains were found to have both UhpTE350Q mutation and fosA6/5 genes in the genome. Only 12 (2.30%) strains carried fosA6/5 genes without UhpTE350Q mutation; 1 (0.19%) strain had only UhpTE350Q mutation without fosA6/5 genes, and another strain contained neither UhpTE350Q mutation nor fosA6/5 genes.@*CONCLUSION@#UhpTE350Q mutation with the presence of fosA6/5 genes are ubiquitous in K. pneumonia genomes, indicating a possible intrinsic mechanism of fosfomycin resistance in the bacterium to limit the use of fosfomycin against infections caused by K. pneumoniae, especially the multi-resistant HvKP/HmKP strains.

Research progress in therapeutic resistance mechanism and therapeutic strategy of cancer stem cells / 国际生物医学工程杂志

Cancer stem cells (CSCs) are a class of cells with self-renewal, differentiation, and tumorigenic potential in tumors. It is currently believed that the resistance of CSCs to chemotherapy and radiotherapy is an important cause of tumor recurrence and metastasis. Researchers have found that related factors in many signaling pathways endow CSCs with the ability to adapt to changes in the microenvironment, including inflammatory factors, hypoxia, low pH, and a lack of nutrients. In recent years, the mechanism of CSCs' resistance to therapy has been studied, mainly including the drug efflux mediated by the ATP-binding cassette transporter, the effect of aldehyde dehydrogenase 1 (ALDH1) activity on tumor stem cells, the enhancement of DNA damage repair and degradation of reactive oxygen species, autophagy, activation of development-related pathways, stimulation of the microenvironment, and EMT. The targeting strategies for CSCs include targeting signaling pathway inhibitors, targeting multidrug resistance, DNA damage repair, ALDH, targeting the tumor microenvironment, immunotherapy, etc. In this review, the research progress in CSCs treatment resistance and related treatment strategies was reviewed.

Detección fenotípica y genotípica de la producción de carbapenemasas tipo NDM-1 y KPC en enterobacterias aisladas en un laboratorio clínico en Maracay, Venezuela / Phenotypic and genotypic detection of the production of carbapenemases type NDM-1 and KPC in isolated Enterobacteriaceae in a clinical laboratory in Maracay, Venezuela

INTRODUCCIÓN: La producción de beta-lactamasas capaces de hidrolizar a los carbapenémicos es uno de los mecanismos de resistencia más preocupantes porque eliminan la última opción terapéutica frente a los microorganismos multi-resistentes. OBJETIVO: Determinar la producción de carbapenemasas tipo KPC y NDM-1, empleando métodos fenotípicos y genotípicos, en enterobacterias aisladas en un laboratorio clínico de la ciudad de Maracay, Venezuela. MÉTODOS: Se determinó la producción de carbapenemasas mediante métodos fenotípicos (según algoritmo de Malbrán) y genotípicos (amplificación de los genes blaNDM-1 y blaKPC por RPC) en enterobacterias aisladas en un laboratorio clínico durante el período marzo-agosto 2018. RESULTADOS: Se identificaron 605 enterobacterias de diferentes especies, siendo Escherichia coli la cepa con mayor porcentaje de aislamiento (61,3%), seguida por Klebsiella pneumoniae (14,9%). Diez y seis enterobacterias (2,64%) fueron positivas para la producción de carbapenemasas: 13 cepas de K. pneumoniae y tres del complejo Enterobacter cloacae. La RPC demostró que 14 cepas (87,5%) contienen el gen blaNDM-1 y dos (12,5%) el gen blaKPC; se observó 100% de concordancia entre la determinación fenotípica y la RPC para ambos grupos de enzimas. CONCLUSIONES: Los resultados mostraron mayor incidencia de la metalo-beta-lactamasa tipo NDM-1, reconocida como una alarma epidemiológica debido a que su rápida diseminación dificulta su control, por lo que la identificación del tipo de enzima permitiría establecer estrategias de manejo y control más certeras con la finalidad de erradicar a dichos patógenos.

BACKGROUND: The production of carbapenem-hydrolyzing beta-lactamases is one of the most concerning resistance mechanisms since it eliminates the last therapeutic option against multidrug resistant microorganisms. AIM: To determine the production of KPC and NDM-1 type carbapenemases, using phenotypic and genotypic methods, in isolated enterobacteria in a clinical laboratory in the city of Maracay, Venezuela. METHODS: The production of carbapenemases was determined by phenotypic (according to the Malbrán algorithm) and genotypic methods (amplification of the blaNDM-1 and blaKPC genes by PCR) in clinical isolates of Enterobacteriaceae during the period March-August 2018. RESULTS: 605 Enterobacteriaceae of different species were identified, being Escherichia coli the strain with the highest percentage of isolation (61.3%), followed by Klebsiella pneumoniae (14.9%). Sixteen strains (2.64%) were positive for carbapenemases production: 13 strains of K. pneumoniae and three of the Enterobacter cloacae complex. PCR showed that 14 strains (87.5%) carry the blaNDM-1 gene and two strains (12.5%) the blaKPC gene; 100% agreement was observed between phenotypic determination and PCR for both groups of enzymes. CONCLUSIONS: The results of this study showed a higher incidence of metallo-beta-lactamase type NDM-1, which rapid dissemination and consequently difficult control has been cause of epidemiological alert. The identification of the type of enzyme would allow establishing more accurate management and control strategies in order to eradicate these pathogens.

Antibacterial activity and inhibition against Staphylococcus aureus NorA efflux pump by ferulic acid and its esterified derivatives

Objective: To evaluate the inhibitory activity of ferulic acid and four of its esterified derivatives (methyl, ethyl, propyl, and butyl) against resistance mechanisms in Staphylococcus aureus strains. Methods: Ferulic acid derivatives were obtained by esterification with methanol, ethanol, propanol, and butanol, and then characterized by hydrogen and carbon-13 nuclear magnetic resonance analysis. The minimum inhibitory concentrations (MIC) of ferulic acid and its esterified derivatives, ethidium bromide, and norfloxacin were obtained using the microdilution test, while the efflux pump inhibition test was conducted by examining reduction in the MICs of norfloxacin and ethidium bromide. Molecular docking was also carried out using the Schrodinger Suite 2015 molecular modeling software. A three-dimensional model of NorA efflux pump was generated using I-TASSER. The best scoring model was used as a receptor for ligand-receptor docking. Results: The methyl and butyl ester derivatives did not demonstrate significant antimicrobial activity. However, a significant synergic effect was evidenced when norfloxacin was combined with the ethyl and propyl esterified derivatives. The docking study demonstrated favorable energy of interaction between ferulate derivatives and NorA, and amino acid residues TYR57, TYR58, and LEU255 were present commonly in stabilizing all complexes. The PCA analysis corroborated the docking hypothesis that the lipophilic character and hydrogen bond interactions were the most relevant characteristics involved with NorA inhibitors. The pharmacokinetic parameters of ferulic acid derivatives showed good ADMET properties, demonstrating that they can be easily absorbed and have no effect or inhibit the cytochrome P450 enzyme complex, revealing their potential as drug candidates. Conclusions: This study provides strong evidence that the molecular basis for this activity is potentially due to the NorA efflux pump.

Current status and progress of the treatment of acute promyelocytic leukemia / 白血病·淋巴瘤

Acute promyelocytic leukemia (APL) is a special type of acute leukemia. The cure rate of APL has been significantly improved in the past decades due to the use of anthracyclines, all-trans retinoic acid and arsenic. Modern stratified treatment of APL further enhances the therapeutic efficacy and reduces the treatment-related toxicity. This article reviews the history of all-trans retinoic acid and arsenic into clinical application, and the characteristics of disease, treatment status of all-trans retinoic acid and arsenic, treatment mechanism and drug resistance mechanism in APL are introduced.

Current status and progress of the treatment of acute promyelocytic leukemia / 白血病·淋巴瘤

Acute promyelocytic leukemia (APL) is a special type of acute leukemia. The cure rate of APL has been significantly improved in the past decades due to the use of anthracyclines, all-trans retinoic acid and arsenic. Modern stratified treatment of APL further enhances the therapeutic efficacy and reduces the treatment-related toxicity. This article reviews the history of all-trans retinoic acid and arsenic into clinical application, and the characteristics of disease, treatment status of all-trans retinoic acid and arsenic, treatment mechanism and drug resistance mechanism in APL are introduced.

Detection of carbapenem resistance genes in Pseudomonas aeruginosa isolates with several phenotypic susceptibility profiles / Detección de genes de resistencia a carbapenémicos en aislados de Pseudomonas aeruginosa con diferentes perfiles de susceptibilidad fenotípica

Abstract Introduction: Pseudomonas aeruginosa display several resistance mechanisms to carbapenems and such variety makes it difficult to infer from the antibiogram. The aim of this study was to determine the carbapenem resistance genes in P. aeruginosa isolates with different profiles of phe-notypic susceptibility to these antibiotics. Materials and methods: From a microbial collection of P aeruginosa isolates from infected patients, 40 isolates with different carbapenem resistance profiles were selected. The carbapenemases genes, and expression of the OprD porin, the MexAB-OprM efflux pump and the p-lactamase AmpC were determined. Results: From a total of 40 isolates evaluted, in 21 (52.5%) any mechanism of resistance evaluated were detected. In the meropenem-resistant group, overexpression of AmpC (n = 1) and decreased expression of MexAB-OprM (n = 2) and OprD (n = 1) were found. A decrease in the expression of MexAB-OprM was observed in imipenem-resistant group (n = 3) and mutations in the gene encoding the OprD porin (n = 1). Finally, the presence of carbapenemases (VIM, n= 3, KPC-2 / VIM, n = 1) was detected in imipenem-meropenem resistant isolates. Conclusion: The phenotypic susceptibility profiles in P aeruginosa isolates were not explained by the molecular mechanisms explored, with the exception of carbapenemase-producing isolates. These results evidence the complexity of the antibiotic resistance mechanisms involved in this bacterium.

Resumen Introducción: Pseudomonas aeruginosa presenta diferentes mecanismos de resistencia a los carbapenémicos, dificultando su inferencia a partir del antibiograma. El objetivo fue determinar los genes de resistencia a car-bapenémicos en aislados de Pseudomonas aeruginosa con diferentes perfiles de susceptibilidad a estos antibióticos. Materiales y métodos: A partir de una colección microbiana de aislados de P. aeruginosa provenientes de pacientes infectados se seleccionaron 40 aislados con diferentes perfiles de resistencia a carbapenémicos y en los cuales se determinaron los genes de car-bapenemasas, la expresión de la porina OprD, la bomba de expulsión MexAB-OprM y la betalactamasa AmpC. Resultados: El 52,5 % de los aislados no presentó ninguno de los mecanismos de resistencia evaluados. En los resistentes a meropenem se encontró sobreexpresión de AmpC (n=1) y disminución de la expresión de MexAB-OprM (n=2) y OprD (n=1). En los resistentes a imipenem se observó disminución en la expresión de MexAB-OprM (n=3) y mutaciones en el gen que codifica la porina OprD (n=1). En aislados resistentes a imipenem y meropenem se detectó la presencia de carbapenemasas (VIM, n=3, KPC/VIM, n=1). Conclusión: Los mecanismos moleculares hallados no explican el fenotipo de resistencia a carbapenémicos, excepto en los aislados productores de carbapenemasas. Estos resultados evidencian la complejidad de los mecanismos implicados en la resistencia antibiótica en esta bacteria.

Antimicrobial resistance in Neisseria gonorrhoeae: history, molecular mechanisms and epidemiological aspects of an emerging global threat

ABSTRACT Neisseria gonorrhoeae is the agent of gonorrhea, a sexually transmitted infection with an estimate from The World Health Organization of 78 million new cases in people aged 15-49 worldwide during 2012. If left untreated, complications may include pelvic inflammatory disease and infertility. Antimicrobial treatment is usually effective; however, resistance has emerged successively through various molecular mechanisms for all the regularly used therapeutic agents throughout decades. Detection of antimicrobial susceptibility is currently the most critical aspect for N. gonorrhoeae surveillance, however poorly structured health systems pose difficulties. In this review, we compiled data from worldwide reports regarding epidemiology and antimicrobial resistance in N. gonorrhoeae, and highlight the relevance of the implementation of surveillance networks to establish policies for gonorrhea treatment.

Study on the Resistance Mechanisms of Carbapenem-Resistant Klebsiella Oxytoca / 现代检验医学杂志

Objective To investigate the resistance mechanism of Carbapenem-Resistant Klebsiella oxytoca.Methods Car-bapenem-Resistant Klebsiellaoxytoca were collected from Fujian Medical University Union Hospital.The modified hodge test (MHT)was used for carbapenemase phenotype screening.The minimum inhibit concentration(MIC)was detected using agar dilution method for 1 7 drugs.PCR and DNA sequencing were used to detect commonβ-Lactamase genes and carbapene-mases genes.Conj ugation experiments demonstrated the transferability of the carbapenem-resistant determinants.Results 5 Carbapenem-Resistant Klebsiella oxytoca of 4 isolates were positive detected by MHT.Minimum inhibit concentration was detected by using agar dilution method for 17 drugs.More than 80% isolates were resistance to nine drugs.2 isolates conju-gated successfully of 5 Carbapenem-Resistant Klebsiella oxytoca Isolates.There were 2 isolates included carbapenemases gene (1 isolates were only IMP producers,1 isolate contained the IMP and KPC),3 isolates produce ESBLs gene.Conclution The due to CRE strains isolated from Fujian Medical University Union Hospital may be metallo-enzyme carbapenemase and KPC gene.And the isolate that produce two Carbapenem-Resistant gene had been found in this hospital.

Antimicrobial resistance and underlying mechanisms in Staphylococcus aureus isolates

Objective To investigate the antimicrobial susceptibility of 97 clinical Staphylococcus aureus (S. aureus) strains against 14 antimicrobials and corresponding resistance mechanisms. Methods The antimicrobial susceptibility of the isolates was determined using a disk diffusion method and antimicrobial resistance genes were screened by polymerase chain reaction. Mutations responsible for ciprofloxacin and rifampicin resistance were investigated by polymerase chain reaction and DNA sequencing. Results All isolates were found to be susceptible to vancomycin. Various rates of resistance to penicillin (83.5%), ampicillin (77.3%), erythromycin (63.9%), tetracycline (16.5%), amoxicillin/clavulanic acid (16.5%), ciprofloxacin (15.5%), trimethoprim/sulfamethoxazole (15.5%), oxacillin (13.4%), fusidic acid (12.4%), rifampin (6.2%), clindamycin (6.2%), gentamicin (6.2%) and mupirocin (5.2%) were determined. In addition, different combinations of resistance genes were identified among resistant isolates. Ciprofloxacin resistant isolates had mutations in codon 84 (Ser84Leu) and 106 (Gly106Asp) in the gyrA gene. Mutations in grlA were mostly related to Ser80Phe substitution. Leu466Ser mutation in the rpoB gene was detected in all rifampin resistant isolates. All methicillin resistant S. aureus isolates were SCCmec type V. Conclusions In conclusion, it was determined that the isolates were resistant to different classes of antimicrobials at varying rates and resistance was mediated by different genetic mechanisms. Therefore, continuous monitoring of resistance in S. aureus strains is necessary to control their resistance for clinically important antimicrobials.

Antimicrobial resistance and underlying mechanisms in Staphylococcus aureus isolates

OBJECTIVE@#To investigate the antimicrobial susceptibility of 97 clinical Staphylococcus aureus (S. aureus) strains against 14 antimicrobials and corresponding resistance mechanisms.@*METHODS@#The antimicrobial susceptibility of the isolates was determined using a disk diffusion method and antimicrobial resistance genes were screened by polymerase chain reaction. Mutations responsible for ciprofloxacin and rifampicin resistance were investigated by polymerase chain reaction and DNA sequencing.@*RESULTS@#All isolates were found to be susceptible to vancomycin. Various rates of resistance to penicillin (83.5%), ampicillin (77.3%), erythromycin (63.9%), tetracycline (16.5%), amoxicillin/clavulanic acid (16.5%), ciprofloxacin (15.5%), trimethoprim/sulfamethoxazole (15.5%), oxacillin (13.4%), fusidic acid (12.4%), rifampin (6.2%), clindamycin (6.2%), gentamicin (6.2%) and mupirocin (5.2%) were determined. In addition, different combinations of resistance genes were identified among resistant isolates. Ciprofloxacin resistant isolates had mutations in codon 84 (Ser84Leu) and 106 (Gly106Asp) in the gyrA gene. Mutations in grlA were mostly related to Ser80Phe substitution. Leu466Ser mutation in the rpoB gene was detected in all rifampin resistant isolates. All methicillin resistant S. aureus isolates were SCCmec type V.@*CONCLUSIONS@#In conclusion, it was determined that the isolates were resistant to different classes of antimicrobials at varying rates and resistance was mediated by different genetic mechanisms. Therefore, continuous monitoring of resistance in S. aureus strains is necessary to control their resistance for clinically important antimicrobials.

Application of MALDI-TOF MS in detection of bacterial resistance mechanisms / 中华临床感染病杂志

Bacterial resistance has become a serious problem that the whole world is facing.Routine bacterial drug resistance testing methods such as K-B test and dilution method are time-consuming and incapable to identify the specific drug resistance mechanism , which can not meet the needs of clinicians. MALDI-TOF MS overcomes the shortcomings of traditional methods and has broad application prospects in detection of bacterial resistance and drug resistance mechanism.This article reviews the recent progress on the application of MALDI-TOF MS in detection of bacterial drug resistance mechanisms.

Study on drug resistance mechanism in carbapenem-resistant Citrobacter freundii and treatment strategies / 重庆医学

Objective To explore the drug resistance mechanisms of carbapenem-resistant Citrobacter freundii (C.freundii) and its treatment strategies.Methods Clinical data of 17 strains of carbapenem-resistant C.freundii from this hospital were collected.Carbapenemase resistant genes were amplifies by polymerase chain reaction (PCR).The agar dilution method and the broth dilution method were used to determine the minimal inhibition concentration (MIC) of single antimicrobial drug and drug combination,the partial inhibitory concentration index (Σ FICI) was calculated.Results Eight strains were found to produce blaNDM-1 and 9 strains produced blaIMP,blaKPC,blaSPM and blaoxA-48 were not detected in the study.Furthermore,the synergistic effect and addictive effect of fosfomycin combined imipenem accounted for 75.00％,in which,the synergistic effect was up to 56.25 ％.the synergistic effect and addictive effect of fosfomycin and cefoperazone/sulbactam accounted for 50.00％.Conclusion Fosfomycin combined with imipenem or cefoperazone/sulbactam has good antibacterial activity in vitro,but imipenem combined with fosfomycin may have better effect.

Study on drug resistance mechanism in carbapenem-resistant Citrobacter freundii and treatment strategies / 重庆医学

Objective To explore the drug resistance mechanisms of carbapenem-resistant Citrobacter freundii (C.freundii) and its treatment strategies.Methods Clinical data of 17 strains of carbapenem-resistant C.freundii from this hospital were collected.Carbapenemase resistant genes were amplifies by polymerase chain reaction (PCR).The agar dilution method and the broth dilution method were used to determine the minimal inhibition concentration (MIC) of single antimicrobial drug and drug combination,the partial inhibitory concentration index (Σ FICI) was calculated.Results Eight strains were found to produce blaNDM-1 and 9 strains produced blaIMP,blaKPC,blaSPM and blaoxA-48 were not detected in the study.Furthermore,the synergistic effect and addictive effect of fosfomycin combined imipenem accounted for 75.00％,in which,the synergistic effect was up to 56.25 ％.the synergistic effect and addictive effect of fosfomycin and cefoperazone/sulbactam accounted for 50.00％.Conclusion Fosfomycin combined with imipenem or cefoperazone/sulbactam has good antibacterial activity in vitro,but imipenem combined with fosfomycin may have better effect.

Bases bioquímicas de la tolerancia al estrés osmótico en hongos fitopatógenos: el caso de Macrophomina phaseolina (Tassi) Goid / Biochemical basis of tolerance to osmotic stress in phytopathogenic fungus: The case of Macrophomina phaseolina (Tassi) Goid

El hongo Macrophomina phaseolina (Tassi) Goid., agente causal de la enfermedad denominada «pudrición carbonosa¼, provoca pérdidas significativas en la producción de cultivos como maíz, sorgo, soya y frijol en México. Este hongo, parásito facultativo, muestra amplia capacidad de adaptación a ambientes estresantes, donde existen altas temperaturas y deficiencia hídrica, condiciones frecuentes en gran parte de la agricultura de dicho país. En este trabajo se describen algunos aspectos básicos de la etiología y la epidemiología de M. phaseolina. Asimismo, se revisa la importancia que guardan las respuestas de este hongo a ambientes estresantes, particularmente la deficiencia hídrica, de acuerdo con caracteres morfológicos y del crecimiento, así como fisiológicos, bioquímicos y de patogenicidad. Finalmente, se presentan algunas perspectivas de estudio del género, que enfatizan la necesidad de mejorar su conocimiento, con base en la aplicación de herramientas tradicionales y de biotecnología, y de dilucidar mecanismos de tolerancia al estrés ambiental, extrapolables a otros microorganismos útiles al hombre.

Fungus Macrophomina phaseolina (Tassi) Goid. is the causative agent of charcoal rot disease which causes significant yield losses in major crops such as maize, sorghum, soybean and common beans in Mexico. This fungus is a facultative parasite which shows broad ability to adapt itself to stressed environments where water deficits and/or high temperature stresses commonly occur. These environmental conditions are common for most cultivable lands throughout Mexico. Here we describe some basic facts related to the etiology and epidemiology of the fungus as well as to the importance of responses to stressed environments, particularly to water deficits, based on morphology and growth traits, as well as on physiology, biochemistry and pathogenicity of fungus M. phaseolina. To conclude, we show some perspectives related to future research into the genus, which emphasize the increasing need to improve the knowledge based on the application of both traditional and biotechnological tools in order to elucidate the mechanisms of resistance to environmental stress which can be extrapolated to other useful organisms to man.

Estado de la resistencia a insecticidas en Aedes aegypti (Diptera: Culicidae) del municipio Pinar del Río / Situation of resistance to insecticides in Aedes aegypti (Diptera: Culicidae) from Pinar del Rio municipality

Introducción: el programa de control de Aedes aegypti (Linnaeus) (Diptera: Culicidae) en Cuba utiliza temefos como larvicida y piretroides como adulticidas, aunque el organofosforado clorpirifos ha sido utilizado esporádicamente. Conocer el nivel de resistencia a estos insecticidas es esencial para lograr un control efectivo de esta especie. Objetivo: determinar el nivel de resistencia a insecticidas en su grado técnico y en sus formulaciones comerciales en Ae. aegypti de Pinar del Río. Métodos: una cepa de Ae. aegypti del Área de Salud Raúl Sánchez, Pinar del Río, fue evaluada a través de los bioensayos de la Organización Mundial de la Salud para determinar la susceptibilidad en larvas al organofosforado temefos en su formulación técnica. Se evaluaron además tres formulaciones granuladas de temefos (Abatex-G1, Biolarv G-1 y Temefar G-1). En el estado adulto se determinó el nivel de susceptibilidad a los insecticidas piretroides: cipermetrina, deltametrina, lambdacialotrina y al organofosforado clorpirifos, en su formulación técnica. Además se evaluaron algunos en su formulación comercial: Galgotrin 25 EC (cipermetrina), Aqua K-Otrina 2 EW (deltametrina) y Clorcide 44 EC (clorpirifos). Resultados: en larvas, se encontró alta resistencia a temefos, en su formulación técnica, y con los productos en su formulación comercial, se observó una efectividad del 100 por ciento, con recambio diario de agua, de hasta 20 días para Temefar G1, 18 días para Biolarv G1 y 12 días para Abatex G1. En los ensayos de adultos, la cepa resultó susceptible a cipermetrina, deltametrina y clorpirifos, y resistente a lambdacialotrina. Con respecto a las tres formulaciones comerciales evaluadas, solo se observó resistencia a Aqua K-Otrina 2 EW. Conclusiones: el uso de estrategias de control integrado de Ae. aegypti se hace necesario para disminuir la frecuencia de uso de temefos, y así recuperar la efectividad de este insecticida. Además, se evitaría la aparición de resistencia a productos adulticidas que aun mantienen su efectividad para el control efectivo de esta especie en la zona de estudio(AU)

Introduction: the control program of Aedes aegypti (Linnaeus) (Diptera: Culicidae) in Cuba uses temephos as larvicide and pyrethroids as adulticide although the organophosphorate chlorpyrifos has been barely used. The level of knowledge about resistance to insecticides is essential to effectively control this species. Objective: to determine the level of resistance to insecticides of Ae. aegypti from Pinar del Rio in its technical aspect and in commercial formulations. Methods: one Ae. aegypti strain from the health area Raul Sánchez in Pinar del Rio province was evaluated through the World Health Organization bioassays to determine susceptibility of larvae to temephos in its technical formulation. Additionally, three granulated formulations of temephos were evaluated (Abatex-G1, Biolarv G-1 and Temefar G-1). In the adult state, the level of susceptibility to pyrethroids called cypermethrin, deltamethrin, lambda cyhalothrine and to organophosphate chlorpyrifos in its technical formulation. Some of them were evaluated in its commercial formulation (Galgotrin 25 EC (cypermethrin), Aqua K-Otrina 2 EW (deltamethrin) and Clorcide 44 EC (chlorpyrifos). Results: it was found in larvae that the resistance to temephos was high in the technical formulation, but the commercial formulation showed an effectiveness rate of 100 percent., with daily change of water, up to 20 days for Temefar G1, 18 days for Biolarv G1 and 12 for Abatex G1. In the assays with adult vectors, the strain turned to be susceptible to cypermethrin, deltamethrin and chlorpyrifos and resistant to lambda cyhalothrin. Regarding the three evaluated commercial formulations, resistance to Aqua K-Otrina 2 EW was proved. Conclusions: the use of integrated control strategies for Ae. aegypti makes it necessary to reduce the frequency of use of temephos and to recover the effectiveness of this insecticide. Moreover, it will avoid the occurrence of resistance to adulticide products that are still effective for the control of this species in the study area(AU)

Resistencia a insecticidas y sus mecanismos bioquímicos en Aedes aegypti del municipio Boyeros en los años 2010 y 2012 / Insecticide resistance and its biochemical mechanisms in Aedes aegypti mosquitoes from the municipality of Boyeros in the years 2010 and 2012

Introducción: el programa de control de Aedes aegypti (L.) (Diptera: Culicidae) en Cuba utiliza fundamentalmente temefos (ABATE) como larvicida y piretroides como adulticidas, y se ha utilizado, esporádicamente, el organofosforado (OF) clorpirifos. El monitoreo de la resistencia a estos insecticidas es esencial para lograr un control efectivo de esta especie. Objetivo: determinar la resistencia a temefos en larvas y sus mecanismos, y evaluar el nivel de resistencia a los insecticidas más utilizados como adulticidasen cinco áreas de salud del municipio Boyeros, La Habana, colectadas indistintamente en los años 2010-2012. Métodos: se evaluó la resistencia a temefos y la eficacia del mismo, en su formulación comercial (ABATEX G1), en larvas, a través de los bioensayos recomendados por la Organización Mundial de la Salud. Los mecanismos de resistencia se realizaron a través de ensayos bioquímicos. La resistencia en el estado adulto se determinó a través del método de las botellas impregnadas. Resultados: la resistencia a temefos en larvas disminuyó del año 2010 al 2012. El producto comercial de temefos mostró 100 por ciento de mortalidad entre 5 y 12 días. Se demostró que las esterasas y monooxigenasas desempeñaron un papel importante en la resistencia a temefos en larvas. En el estado adulto, se observó resistencia a piretroides y a clorpirifos en algunas cepas. Conclusiones: estos resultados corroboran la necesidad de establecer estrategias de control integrado para preservar la vida útil de los insecticidas disponibles para el control de Ae. aegypti en el municipio Boyeros(AU)

Introduction: the program for control of Aedes aegypti (L.) (Diptera: Culicidae) in Cuba is mainly based on the use of temephos (Abate) as larvicide and pyrethroids as adulticides. Organophosphate (OP) insecticide Chlorpyrifos has also been used on occasion. Monitoring resistance to these insecticides is essential to achieve effective control of the species. Objective: determine temephos resistance in larvae and its mechanisms, and evaluate the level of resistance to the insecticides most commonly used as adulticides in five health areas from the municipality of Boyeros, Havana, surveyed in the years 2010 and 2012. Methods: an evaluation was conducted of resistance to and effectiveness of temephos in its commercial formulation (Abatex G1) in larvae, using tests recommended by the World Health Organization. Resistance mechanisms were assessed with biochemical assays. The impregnated bottle bioassay was used to determine resistance in the adult stage. Results: larval resistance to temephos decreased from 2010 to 2012. The commercial product temephos showed 100 percent mortality between 5 and 12 days. Esterases and monooxygenases were found to play an important role in larval resistance to temephos. Some strains showed resistance to pyrethroids and Chlorpyrifos in the adult stage. Conclusions: these results corroborate the need to set up integrated control strategies to preserve the useful life of the insecticides available to control Aedes aegypti in the municipality of Boyeros(AU)

Drug Resistance in Malaria-in a nutshell.

One peek into the history of malaria, shows us that despite many attempts by mankind to counter the development and propagation of malaria, it has always risen back like a ‘phoenix from its ashes’. This has been possible by virtue of the singular ability of the malarial parasite to mutate and evade the actions of various anti-malarial drugs. The emergence of drug resistant malarial parasites by virtue of the various molecular mechanisms, has put the authorities under the cosh and forced the scientists to start generating newer and better anti-malarial drugs. In this review, we have dwelt upon the various molecular mechanisms which have allowed the malaria parasite to develop resistance, as it can serve to educate the scientists in their effort to generate newer anti-malarials.

Characterization of Enzymatic profiles of Aedes aegypti strains from the State of Rio Grande do Norte, Brazil / Caracterização de perfis enzimáticos de cepas do Aedes aegypti do Estado do Rio Grande do Norte, Brasil

Abstract This study was conducted in four strains of Aedes aegypti mosquitoes to evaluate the enzymatic activity profiles in the city of Mossoró, Rio Grande do Norte, and correlate them with biochemical mechanisms of resistance to insecticides. Mosquitos were used to quantify the following detoxification enzymes: Mixed-Function Oxidase (MFO), PNPA-esterase (PNPA-EST), and Acetylcholinesterase (AChE). The profiles were compared statistically with profiles from the Rockefeller strain, through the Kruskal-Wallis test and Dunn's multiple comparisons (p < 0.05). The 99 percentile of the values of enzyme activity from the reference strain was calculated for each enzyme, and the percentage of individuals above the 99 percentile was quantified. The enzyme activities were classified as “Unchanged” (< 15%), “Identified change” (> 15% and < 50%), and “Substantially changed” (> 50%). The statistical analysis revealed significant differences in the MFO and AChE profiles, which are fundamental in the determination of profiles of resistance to insecticides. Three populations were classified as “Substantially changed” for MFO. The altered enzymatic activity showed that the changes could have an important role in exposing resistance to insecticides.

Resumo Este estudo foi realizado em quatro cepas de mosquitos Aedes aegypti da cidade de Mossoró, Rio Grande do Norte, com o intuito de avaliar os perfis de atividade enzimática e correlacioná-los com os mecanismos bioquímicos de resistência a inseticidas. Mosquitos foram utilizados para quantificar as seguintes enzimas de detoxificação: oxidase de Função Mista (MFO), PNPA-esterase (PNPA-EST) e acetilcolinesterase (AChE). Os perfis das populações foram comparados estatisticamente com os da cepa Rockefeller por meio do teste de Kruskal-Wallis e do de comparações múltiplas de Dunn (p < 0,05). O percentil 99 dos valores de atividade enzimática da cepa referência foi calculado para cada enzima, e o percentual de indivíduos acima desse valor foi quantificado. As atividades enzimáticas foram classificadas como “Inalterada” (< 15%), “Alteração Identificada” (> 15% e < 50%), e “Substancialmente Alterada” (> 50%). A análise estatística revelou diferenças significativas nos perfis de MFO e AChE, que são fundamentais na determinação de perfis de resistência a inseticidas. Três populações foram classificadas como “Substancialmente Alteradas” para MFO. Os níveis alterados de atividade enzimática demonstram que essa mudança pode desempenhar um importante papel na resistência a inseticidas.

The drug resistance and molecular mechanisms of human Campylobacter jejuni / 中华传染病杂志

Objective To analyze the characteristics of drug resistance to quinolones and erythromycin of clinical Campylobacter jejuni (C .jejuni) strains and to further investigate its molecular mechanisms .Methods A total of 193 clinical C .jejuni strains were isolated from feces of patients with diarrhea .Drug susceptibilities to ciprofloxacin (CIP ) , gentamycin (GEN ) , azithromycin (AZI ) , erythromycin (ERY) ,chloromycetin (CHL) ,doxycycline (DOX) and tetracycline (TET) were tested using standard agar dilution method . gyrA , gyrB and parC genes were amplified by polymerase chain reaction (RCR) and analyzed for molecular mechanisms of quinolones resistance ,and 23S rRNA , rplD and rplV genes for erythromycin resistance .Chi‐square test or Fisher′s exact two‐tailed tests were used to perform the statistical analysis .Results A total of 193 clinical C . jejuni strains were isolated during 1994—2010 ,among which 43 C .jejuni strains were isolated in 1994—1999 ,80 in 2000—2005 and 70 in 2006—2010 .The drug resistance rates for CIP increased significantly from 55 .8% in 1994—1999 to 95 .0% in 2000—2005 and 94 .3% in 2005—2010 (χ2=41 .94 ,P<0 .01) .The drug resistance rates for GEN were 0 in 1994—1999 ,11 .3% in 2000—2005 and 10 .0% in 2006—2010 ,but with no statistic difference (χ2=5 .078 , P=0 .08) .The drug resistance rates for AZI were 0 in 1994—1999 ,3 .8% in 2000—2005 and 4 .3% in 2006—2010 (χ2=1 .81 ,P=0 .40) .The drug resistance rates for ERY were 0 in 1994—1999 ,1 .3% in 2000—2005 and 4 .3% in 2006—2010 (χ2 = 2 .87 , P= 0 .24 ) . T he drug resistance rates for CHL were 2 .3% in 1994—1999 ,11 .3% in 2000—2005 and 20 .0% in 2006—2010 (χ2 =7 .82 ,P=0 .02) .The drug resistance rates for DOX were 60 .5% in 1994‐1999 ,86 .3% in 2000—2005 and 82 .9% in 2006—2010 (χ2 =12 .18 ,P<0 .01) .The drug resistance rates for TET were 74 .4%in 1994—1999 ,95 .0% in 2000—2005 and 94 .3% in 2006—2010 (χ2 = 15 .46 , P< 0 .01 ) .T he drug resistance rates for CIP‐DOX‐TET were 37 .2% in 1994—1999 ,83 .8% in 2000—2005 and 80 .0% in 2006—2010 (χ2 =33 .53 ,P<0 .01) .The drug resistance rates for CHL‐CIP‐DOX‐TET were 0 in 1994—1999 ,7 .5% in 2000—2005 and 20 .0% in 2006—2010 (χ2=12 .68 ,P<0 .01) .The drug resistance rates for GEN‐CIP‐DOX‐TET were 0 in 1994—1999 ,7 .5% in 2000—2005 and 8 .6% in 2006—2010 (χ2 =3 .74 ,P=0 .15) .All 163 CIP‐resistant C .jejuni strains had C257T mutation on gyrA gene .Mutations on gyrB gene were silent .ParC gene was absent in C .jejuni .Four ERY resistant C .jejuni strains had no mutation on rplD and rplV genes , but 3 of them had A2075G mutation on 23S rRNA gene . Conclusions The antimicrobial resistance rates for C .jejuni increase remarkably over the periods .C257T mutation on gyrA gene and A2075G mutation on 23S rRNA gene are main mechanisms for quinolones resistance and erythromycin resistance ,respectively .