Risk of resistance and cross-resistance development to selection with imidacloprid and level of heritability in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae): a potential pest of cotton

2020 ◽  
Author(s):  
Mamuna Ijaz ◽  
Sarfraz Ali Shad
Keyword(s):  
Cross Resistance ◽  
Resistance Development ◽  
Potential Pest ◽  
Oxycarenus Hyalinipennis

scholarly journals Comparative Study of the Effect of Solvents on the Efficacy of Neonicotinoid Insecticides Against Malaria Vector Populations Across Africa

2022 ◽  
Author(s):  
Magellan Tchouakui ◽  
Tatiane Assatse ◽  
Leon M. J. Mugenzi ◽  
Benjamin D. Menze ◽  
Daniel Nguiffo-Nguete ◽  
...  
Keyword(s):  
Democratic Republic Of Congo ◽  
Natural Populations ◽  
Resistance Mechanisms ◽  
Lower Mortality ◽  
Malaria Vectors ◽  
Cross Resistance ◽  
Metabolic Resistance ◽  
Resistance Development ◽  
Development Of Resistance ◽  
Bottle Test

Abstract Background New insecticides with a novel mode of action such as neonicotinoids have recently been recommended for public health by WHO. Resistance monitoring of such novel insecticides requires a robust protocol to monitor the development of resistance in natural populations. In this study, we comparatively used three different solvents to assess the susceptibility of malaria vectors to neonicotinoids across Africa.MethodsMosquitoes were collected from May to July 2021 from three agricultural settings in Cameroon (Njombe-Penja, Nkolondom, and Mangoum), the Democratic Republic of Congo (Ndjili-Brasserie), Ghana (Obuasi), and Uganda (Mayuge). Using the CDC bottle test, we compared the effect of three different solvents (ethanol, acetone, MERO) on the efficacy of neonicotinoids against Anopheles gambiae s.l. In addition, TaqMan assays were used to genotype key pyrethroid-resistant markers in An. gambiae and to evaluate potential cross-resistance between pyrethroids and clothianidin.ResultsLower mortality were observed when using absolute ethanol or acetone alone as solvent (11.4- 51.9% mortality in Nkolondom, 31.7- 48.2% in Mangoum, 34.6- 56.1% in Mayµge, 39.4- 45.6% in Obuasi, 83.7- 89.3% in Congo and 71.05- 95.9% in Njombe pendja) compared to acetone + MERO for which 100% mortality were observed for all the populations. Synergist assays (PBO, DEM and DEF) revealed a significant increase of mortality suggesting that metabolic resistance mechanisms are contributing to the reduced susceptibility. A negative association was observed between the L1014F-kdr mutation and clothianidin resistance with a greater frequency of homozygote resistant mosquitoes among the dead than among survivors (OR=0.5; P=0.02). However, the I114T-GSTe2 was in contrast significantly associated with a greater ability to survive clothianidin with a higher frequency of homozygote resistant among survivors than other genotypes (OR=2.10; P=0.013). ConclusionsThis study revealed a contrasted susceptibility pattern depending on the solvents with ethanol/acetone resulting to lower mortality, thus possibly overestimating resistance, whereas the MERO consistently showed a greater efficacy of neonicotinoids but it could prevent to detect early resistance development. Therefore, we recommend monitoring the susceptibility using both acetone alone and acetone+MERO (8-10µg/ml for clothianidin) to capture the accurate resistance profile of the mosquito populations.

scholarly journals Evidence for the Predisposition of Fungicide-Resistant Isolates of Venturia inaequalis to a Preferential Selection for Resistance to Other Fungicides

2001 ◽  
Vol 91 (8) ◽  
pp. 776-781 ◽  
Author(s):  
Wolfram Köller ◽  
W. F. Wilcox
Keyword(s):  
Fungicide Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
The United States ◽  
Cross Resistance ◽  
Resistance Development ◽  
Flexible Response ◽  
Sterol Demethylation Inhibitors ◽  
Selection For ◽  
Selection Of

In the United States, populations of the apple scab pathogen Venturia inaequalis have progressed through three consecutive rounds of fungicide resistance development, first to dodine, then to the benzimidazoles, and most recently to the sterol demethylation inhibitors (DMIs). Analysis of extensive monitoring data have to date provided no indication of detectable cross-resistance or partial cross-resistance of V. inaequalis populations to the three unrelated classes of fungicides prior to the selection of resistant subpopulations. However, in this study, resistance to both benomyl and DMIs developed to significantly higher frequencies within the previously established dodine-resistant population than in the population sensitive to dodine. Accelerated selection of phenotypes double resistant to dodine and the DMI fenarimol was apparent over the course of distinct seasons of apple scab management with either dodine or fenarimol. The data provide evidence for an accelerated speed of resistance development among phenotypes of V. inaequalis already resistant to an unrelated fungicide. This finding represents a departure from the previous model, which assumed entirely independent rounds of resistance developments. The data indicate that phenotypes of V. inaequalis might not only be selected for the trait of fungicide resistance but also for traits allowing a more flexible response to changes in the environment where they compete.

scholarly journals Resistance to Fluopyram, Fluxapyroxad, and Penthiopyrad in Botrytis cinerea from Strawberry

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Achour Amiri ◽  
Stacy M. Heath ◽  
Natalia A. Peres
Keyword(s):  
Succinate Dehydrogenase ◽  
Botrytis Cinerea ◽  
High Resistance ◽  
Gray Mold ◽  
Cross Resistance ◽  
The Novel ◽  
Resistance Development ◽  
Dehydrogenase Gene ◽  
Resistance Patterns ◽  
Subunit B

Succinate dehydrogenase inhibitors (SDHIs) constitute a mainstay in management of gray mold caused by Botrytis cinerea in strawberry and several other crops. In this study, we investigated the risks of resistance development to three newer SDHIs (i.e., fluopyram, fluxapyroxad, and penthiopyrad) and their cross-resistance with the previously registered boscalid. We investigated the mutations in the SdhB subunit and evaluated their impact on microbial fitness in field populations of B. cinerea. Amino acid substitutions associated with resistance to SDHIs were detected at three codons of the SdhB subunit (BH272R/Y/L, BP225F, and BN230I) in the succinate dehydrogenase gene of field isolates from Florida. The BH272R, BH272Y, BH272L, BP225F, and BN230I mutations were detected at frequencies of 51.5, 28.0, 0.5, 2.5, and 4%, respectively. Strong cross-resistance patterns were evident between boscalid and fluxapyroxad and penthiopyrad but not with fluopyram, except in BH272L, BP225F, and BN230I mutants. All five mutations conferred moderate to very high resistance to boscalid whereas the BH272Y conferred resistance to fluxapyroxad and penthiopyrad. The BH272L, BN230I, and BP225F mutations conferred high resistance to all four SDHIs tested. Resistance monitoring following the first use of penthiopyrad in strawberry fields in Florida in 2013 suggests potential for quick selection for highly resistant populations and warrants careful use of the newer SDHIs. No evidence of major fitness costs due to the mutations in the SdhB subunit was found, which indicates the potential ability of the mutants to survive and compete with wild-type isolates. Our study suggests high risks for rapid widespread occurrence of B. cinerea populations resistant to the novel SDHIs unless appropriate rotation strategies are implemented immediately upon registration.

scholarly journals Investigations of the Mode of Action and Resistance Development of Cadazolid, a New Antibiotic for Treatment of Clostridium difficile Infections

2013 ◽  
Vol 58 (2) ◽  
pp. 901-908 ◽  
Author(s):  
Hans H. Locher ◽  
Patrick Caspers ◽  
Thierry Bruyère ◽  
Susanne Schroeder ◽  
Philippe Pfaff ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Clostridium Difficile ◽  
Dna Synthesis ◽  
Mode Of Action ◽  
Cross Resistance ◽  
Resistance Development ◽  
Content Type ◽  
Inhibition Of Protein Synthesis ◽  
Inhibitor Of Protein Synthesis ◽  
Inhibition Of Dna Synthesis

ABSTRACTCadazolid is a new oxazolidinone-type antibiotic currently in clinical development for the treatment ofClostridium difficile-associated diarrhea. Here, we report investigations on the mode of action and the propensity for spontaneous resistance development inC. difficilestrains. Macromolecular labeling experiments indicated that cadazolid acts as a potent inhibitor of protein synthesis, while inhibition of DNA synthesis was also observed, albeit only at substantially higher concentrations of the drug. Strong inhibition of protein synthesis was also obtained in strains resistant to linezolid, in agreement with low MICs against such strains. Inhibition of protein synthesis was confirmed in coupled transcription/translation assays using extracts from differentC. difficilestrains, including strains resistant to linezolid, while inhibitory effects in DNA topoisomerase assays were weak or not detectable under the assay conditions. Spontaneous resistance frequencies of cadazolid were low in all strains tested (generally <10−10at 2× to 4× the MIC), and in multiple-passage experiments (up to 13 passages) MICs did not significantly increase. Furthermore, no cross-resistance was observed, as cadazolid retained potent activity against strains resistant or nonsusceptible to linezolid, fluoroquinolones, and the new antibiotic fidaxomicin. In conclusion, the data presented here indicate that cadazolid acts primarily by inhibition of protein synthesis, with weak inhibition of DNA synthesis as a potential second mode of action, and suggest a low potential for spontaneous resistance development.

scholarly journals Development of a Protocol for Predicting Bacterial Resistance to Microbicides

2015 ◽  
Vol 81 (8) ◽  
pp. 2652-2659 ◽  
Author(s):  
Laura Knapp ◽  
Alejandro Amézquita ◽  
Peter McClure ◽  
Sara Stewart ◽  
Jean-Yves Maillard
Keyword(s):  
Antibiotic Susceptibility ◽  
Burkholderia Cepacia ◽  
Bacterial Resistance ◽  
Low Cost ◽  
The United States ◽  
Cross Resistance ◽  
Early Assessment ◽  
Resistance Development ◽  
Content Type ◽  
Development Of Resistance

ABSTRACTRegulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of the development of resistance in organisms targeted by microbicidal products. There is no standard protocol to assess the risk of the development of resistance to microbicidal formulations. This study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. Three industrial isolates (Pseudomonas aeruginosa,Burkholderia cepacia, andKlebsiella pneumoniae) and twoSalmonella entericaserovar Typhimurium strains (SL1344 and 14028S) were exposed to a shampoo, a mouthwash, eye makeup remover, and the microbicides contained within these formulations (chlorhexidine digluconate [CHG] and benzalkonium chloride [BZC]) under realistic, in-use conditions. Baseline and postexposure data were compared. No significant increases in the MIC or the minimum bactericidal concentration (MBC) were observed for any strain after exposure to the three formulations. Increases as high as 100-fold in the MICs and MBCs of CHG and BZC for SL1344 and 14028S were observed but were unstable. Changes in antibiotic susceptibility were not clinically significant. The use of MICs and MBCs combined with antibiotic susceptibility profiling and stability testing generated reproducible data that allowed for an initial prediction of the development of resistance to microbicides. These approaches measure characteristics that are directly relevant to the concern over resistance and cross-resistance development following the use of microbicides. These are low-cost, high-throughput techniques, allowing manufacturers to provide to regulatory bodies, promptly and efficiently, data supporting an early assessment of the risk of resistance development.

scholarly journals Azithromycin in Pseudomonas aeruginosa Biofilms: Bactericidal Activity and Selection of nfxB Mutants

2009 ◽  
Vol 53 (4) ◽  
pp. 1552-1560 ◽  
Author(s):  
Xavier Mulet ◽  
María D. Maciá ◽  
Ana Mena ◽  
Carlos Juan ◽  
José L. Pérez ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bactericidal Activity ◽  
Cross Resistance ◽  
Resistance Development ◽  
Viable Cells ◽  
Knockout Mutants ◽  
Lung Infections ◽  
Selection Of

ABSTRACT Azithromycin (AZM) has shown promising results in the treatment of Pseudomonas aeruginosa chronic lung infections such as those occurring in cystic fibrosis (CF) patients. We evaluated the effect of hypermutation and alginate hyperproduction on the bactericidal activity and resistance development to AZM in P. aeruginosa biofilms. Strains PAO1, its mucA mutant (PAOMA), and their respective mutS-deficient hypermutable derivatives (PAOMS and PAOMSA) were used. Biofilms were incubated with several AZM concentrations for 1, 2, 4, or 7 days, and the numbers of viable cells were determined. During the first 2 days, AZM showed bactericidal activity for all the strains, but in extended AZM incubation for strain PAOMS and especially strain PAOMSA, a marked increased in the number of viable cells was observed, particularly at 4 μg/ml. Biofilms formed by the lineages recovered from the 7-day experiments showed enhanced AZM resistance. Furthermore, most of the independent lineages studied, including those obtained from biofilms treated with AZM concentrations as low as 0.5 μg/ml, showed MexCD-OprJ hyperexpression and mutations in nfxB. The role of nfxB mutation in AZM resistance was further confirmed through the characterization of nfxB and mexD knockout mutants. Results from this work show that, although AZM exhibits bactericidal activity against P. aeruginosa biofilms, resistant mutants are readily selected and that, furthermore, they frequently show cross-resistance to other unrelated antipseudomonal agents such as ciprofloxacin or cefepime but hypersusceptibility to others such as imipenem or tobramycin. Therefore, these results should help guide the selection of appropriate antipseudomonal therapies in CF patients under AZM maintenance treatment.

scholarly journals Detection and Molecular Characterization of Resistance to the Dicarboximide and Benzamide Fungicides in Botrytis cinerea From Tomato in Hubei Province, China

Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1299-1306 ◽  
Author(s):  
M. Adnan ◽  
M. S. Hamada ◽  
G. Q. Li ◽  
C. X. Luo
Keyword(s):  
Botrytis Cinerea ◽  
Management Strategies ◽  
Resistance Management ◽  
Point Mutations ◽  
Hubei Province ◽  
Cross Resistance ◽  
Resistance Development ◽  
Fitness Parameters ◽  
The Mean

Altogether, 192 Botrytis cinerea isolates collected from tomato greenhouses at different locations in Hubei Province were evaluated for their sensitivity to fungicides procymidone and zoxamide. The mean effective concentration to cause 50% growth inhibition (EC50) values of procymidone for sensitive and resistant isolates were 0.25 and 3.60 μg/ml, respectively. The frequency of procymidone-resistant (ProR) isolates was 18%, and the highest frequency was recorded in Jingmen. Positive cross-resistance was observed for ProR isolates to other dicarboximide fungicides but not to phenylpyrroles. Significant differences were observed for fitness parameters (i.e., mycelial growth, osmotic sensitivity, and virulence between sensitive and resistant isolates). Amino acid sequence of the Bos1 gene revealed that ProR isolates carried either point mutations at codon 365 (I365S) or a pair of point mutations at codons 369 (Q369P) and 373 (N373S). For zoxamide, the mean EC50 values for sensitive and resistant isolates were 0.22 and 5.32 μg/ml, respectively. Approximately 14% of the isolates were found to be resistant to zoxamide, and the highest frequency of resistance was also observed in Jingmen. There was positive cross-resistance for zoxamide-resistant (ZoxR) isolates to carbendazim. No significant differences were observed for fitness parameters between zoxamide-sensitive and ZoxR isolates. Sequence analysis of the β-tubulin gene of Botrytis cinerea revealed two previously reported point mutations (E198A and E198K) and one new point mutation (T351I). This new mutation was detected in only those isolates which possessed the E198K but not E198A substitution. This study allows for a better understanding of the resistance development profile in Hubei Province. Results will be useful for the improvement of fungicide resistance management strategies.

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