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1.
Dis Aquat Organ ; 158: 21-25, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38661134

RESUMO

In order to establish the meaning of data generated in antimicrobial agent susceptibility tests, it is necessary to develop internationally harmonised interpretive criteria. Currently, such criteria have not been developed for data generated in studies of the susceptibility of the fish pathogen Yersinia ruckeri. This work generated the data that would be required to set epidemiological cut-off values for the susceptibility data of this species that had been generated using a standardised disc diffusion method that specified the use of Mueller Hinton agar and incubation at 22°C for 24-28 h. Using this method, sets of inhibition zones data for 4 antimicrobial agents were generated by 3 independent laboratories. The data from these laboratories were aggregated and analysed using the statistically based normalised resistance interpretation. For ampicillin, florfenicol, oxytetracycline and trimethoprim-sulfamethoxazole the cut-off values calculated by this analysis were ≥16, ≥23, ≥24 and ≥30 mm, respectively. Evidence is presented demonstrating that the data for these 4 agents was of sufficient quantity and quality that they could be used by the relevant authorities to set internationally harmonised, consensus epidemiological cut-off values for Y. ruckeri.


Assuntos
Antibacterianos , Doenças dos Peixes , Yersinia ruckeri , Antibacterianos/farmacologia , Doenças dos Peixes/microbiologia , Doenças dos Peixes/epidemiologia , Yersinia ruckeri/efeitos dos fármacos , Animais , Testes de Sensibilidade Microbiana , Yersiniose/veterinária , Yersiniose/microbiologia , Yersiniose/epidemiologia , Farmacorresistência Bacteriana , Peixes
2.
Dis Aquat Organ ; 156: 115-121, 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38095366

RESUMO

This work generates the data needed to set epidemiological cut-off values for disc-diffusion zone measurements of Vibrio cholerae. The susceptibility of 147 European isolates of non-O1/non-O139 V. cholerae to 19 antibiotics was established using a standardised disc diffusion method which specified incubation of Mueller Hinton agar plates at 35°C. Epidemiological cut-off values were calculated by analysis of the zone size data with the statistically based normalised resistance interpretation method. Cut-off values for 17 agents were calculated by analysis of the aggregated data from all 4 laboratories participating in this study. The cut-off values calculated were ≥18 mm for amoxicillin/clavulanate, ≥18 mm for amikacin, ≥19 mm for ampicillin, ≥27 mm for cefepime, ≥31 mm for cefotaxime, ≥24 mm for ceftazidime, ≥24 mm for chloramphenicol, ≥31 mm for ciprofloxacin, ≥16 mm for erythromycin, ≥ 27 mm for florfenicol, ≥16 mm for gentamicin, ≥23 mm for imipenem, ≥25 mm for meropenem, ≥29 mm for nalidixic acid, ≥28 mm for norfloxacin, ≥13 mm for streptomycin and ≥23 mm for tetracycline. For the other 2 agents the data from 1 laboratory was excluded from the censored aggregation because the data from that laboratory was considered excessively imprecise. The cut-off values for these 2 agents calculated for the aggregation of the data from 3 laboratories were ≥23 mm for trimethoprim and ≥24 mm for trimethoprim/sulfamethoxazole. These zone size data will be submitted to the Clinical Laboratory Standards Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) for their consideration in setting international consensus epidemiological cut-off values for non O1/non-O139 V. cholerae.


Assuntos
Antibacterianos , Vibrio cholerae , Animais , Testes de Sensibilidade Microbiana/veterinária , Antibacterianos/farmacologia , Ciprofloxacina , Trimetoprima
3.
Dis Aquat Organ ; 155: 109-123, 2023 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-37650482

RESUMO

This work aims to generate the data needed to set epidemiological cut-off values for minimum inhibitory concentration (MIC) and disc-diffusion zone measurements of Vibrio anguillarum. A total of 261 unique isolates were tested, applying standard methods specifying incubation at 28°C for 24-28 h. Aggregated MIC distributions for a total of 247 isolates were determined in 9 laboratories for 11 agents. Data aggregations of the disc zone for the 10 agents analysed contained between 157 and 218 observations made by 4 to 7 laboratories. Acceptable ranges for quality control (QC) reference strains were available for 7 agents and the related multi-laboratory aggregated data were censored, excluding the data of a laboratory that failed to meet QC requirements. Statistical methods were applied to calculate epidemiological cut-off values. Cut-off values for MIC data were calculated for florfenicol (≤1 µg ml-1), gentamicin (≤4 µg ml-1), oxytetracycline (≤0.25 µg ml-1) and trimethoprim/sulfamethoxazole (≤0.125/2.38 µg ml-1). The cut-off values for disc zone data were calculated for enrofloxacin (≥29 mm), florfenicol (≥27 mm), gentamicin (≥19 mm), oxolinic acid (≥24 mm), oxytetracycline (≥24 mm) and trimethoprim/sulfamethoxazole (≥26 mm). MIC and disc-diffusion zone data for the other agents where not supported by QC, thus yielding only provisional cut-off values (meropenem, ceftazidime). Regardless of whether QC is available, some of the aggregated MIC distributions (enrofloxacin, oxolinic acid), disc zone (sulfamethoxazole), and MIC and disc-diffusion distributions (ampicillin, chloramphenicol) did not meet the statistical requirements. The data produced will be submitted to the Clinical Laboratory Standards Institute for their consideration in setting international consensus epidemiological cut-off values.


Assuntos
Ácido Oxolínico , Oxitetraciclina , Animais , Enrofloxacina , Gentamicinas , Testes de Sensibilidade Microbiana/veterinária , Sulfametoxazol , Trimetoprima
4.
Lett Appl Microbiol ; 71(5): 531-541, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32726860

RESUMO

The present study was aimed at determining antimicrobial susceptibility by a CLSI standard microdilution testing protocol and detecting the resistance genes of motile Aeromonas species isolated from cultured fish. The importance of the minimum inhibitory concentrations was assessed based on statistically determined epidemiological cut-off values calculated by normalized resistance analysis. Unfortunately, CLSI epidemiological cut-off values are available only for Aeromonas salmonicida, and there is no further detailed data on Aeromonas isolated from aquatic animals. The antimicrobial susceptibilities of pre-identified motile Aeromonas species to florfenicol, tetracycline and sulfamethoxazole were determined by calculating epidemiological cut-off values with fully automated and freely available Excel spreadsheets, applying the normalized resistance interpretation (NRI) method. Furthermore, the presence of the antimicrobial resistance genes floR, tetA, tetB, tetC, tetD, tetE, tetH, sulI, sulII and sulIII was detected by PCR analysis and confirmed by sequence analysis. The presence of up to six different genes (multiple antimicrobial resistance) was determined in the Aeromonas isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: Significance and Impact of the Study: In this study, we investigated phenotypic and genotypic antimicrobial resistance characteristics by a novel method based on epidemiological cut-off values. This is the second comprehensive study on the antimicrobial susceptibility characteristics of Aeromonas species using NRI and epidemiological cut-off values. The present research is related to our previous researches focussed on the identification of motile Aeromonads, their prevalence in relation to different fish lengths, seasons and regions, and covered the investigation of Lactococcus garvieae, Yersinia ruckeri, Flavobacterium spp., Enterobacter spp. and Citrobacter spp.


Assuntos
Aeromonas salmonicida/efeitos dos fármacos , Antibacterianos/farmacologia , Sulfametoxazol/farmacologia , Tetraciclina/farmacologia , Tianfenicol/análogos & derivados , Aeromonas salmonicida/genética , Aeromonas salmonicida/isolamento & purificação , Animais , Farmacorresistência Bacteriana/genética , Peixes/microbiologia , Testes de Sensibilidade Microbiana , Tianfenicol/farmacologia
5.
J Fish Dis ; 39(2): 143-54, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25546427

RESUMO

Epidemiological cut-off values were developed for application to antibiotic susceptibility data for Flavobacterium psychrophilum generated by standard CLSI test protocols. The MIC values for ten antibiotic agents against Flavobacterium psychrophilum were determined in two laboratories. For five antibiotics, the data sets were of sufficient quality and quantity to allow the setting of valid epidemiological cut-off values. For these agents, the cut-off values, calculated by the application of the statistically based normalized resistance interpretation method, were ≤16 mg L(-1) for erythromycin, ≤2 mg L(-1) for florfenicol, ≤0.025 mg L(-1) for oxolinic acid (OXO), ≤0.125 mg L(-1) for oxytetracycline and ≤20 (1/19) mg L(-1) for trimethoprim/sulphamethoxazole. For ampicillin and amoxicillin, the majority of putative wild-type observations were 'off scale', and therefore, statistically valid cut-off values could not be calculated. For ormetoprim/sulphadimethoxine, the data were excessively diverse and a valid cut-off could not be determined. For flumequine, the putative wild-type data were extremely skewed, and for enrofloxacin, there was inadequate separation in the MIC values for putative wild-type and non-wild-type strains. It is argued that the adoption of OXO as a class representative for the quinolone group would be a valid method of determining susceptibilities to these agents.


Assuntos
Antibacterianos/farmacologia , Doenças dos Peixes/microbiologia , Infecções por Flavobacteriaceae/veterinária , Flavobacterium/efeitos dos fármacos , Animais , Farmacorresistência Bacteriana , Infecções por Flavobacteriaceae/epidemiologia , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes
7.
Antibiotics (Basel) ; 12(12)2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-38136760

RESUMO

Streptococcus agalactiae is a major health concern in tilapia farming worldwide. In contrast to the availability of susceptibility profile results, interpretative criteria for disk diffusion assays and the influence of serotypes on resistance profiles are not available. To address this, sixty isolates (thirty of each serotype, Ib and III) were evaluated using the disk diffusion assay against six antibiotics, and the epidemiological cut-off value (ECV) was calculated. All the isolates were classified as non-wild type (NWT) for sulfamethoxazole (SUT) and norfloxacin (NOR). The inhibition zones for oxytetracycline (OXY) and doxycycline (DOX) were largely distinct; all serotype Ib and III isolates were classified as wild-type (WT) and NWT, respectively. The results for serotype III of fish group B Streptococcus (GBS) were comparable to the NWT tetracycline profile of human GBS available in EUCAST, suggesting the presence of resistance mechanisms in these fish isolates. The calculation of the cut-off wild type (COWT) values for OXY and DOX was appropriate for both serotypes. Differences between the distribution of florfenicol (FLO) and amoxicillin (AMO) were found, and we attribute this to the faster growth rate of serotype III, which promotes smaller inhibition zones. Therefore, using separate COWT for each serotype is necessary. In conclusion, the serotype of fish GBS affects its susceptibility profile, and it is recommended to use serotype-specific COWT values as interpretative criteria for disk diffusion assays against FLO and AMO.

8.
Access Microbiol ; 5(7)2023.
Artigo em Inglês | MEDLINE | ID: mdl-37601443

RESUMO

Introduction: Existing breakpoint guidelines are not optimal for interpreting antimicrobial resistance (AMR) data from animal studies and low-income countries, and therefore their utility for analysing such data is limited. There is a need to integrate diverse data sets, such as those from low-income populations and animals, to improve data interpretation. Gap statement: There is very limited research on the relative merits of clinical breakpoints, epidemiological cut-offs (ECOFFs) and normalized resistance interpretation (NRI) breakpoints in interpreting microbiological data, particularly in animal studies and studies from low-income countries. Aim: The aim of this study was to compare antimicrobial resistance in Escherichia coli isolates using ECOFFs, CLSI and NRI breakpoints. Methodology: A total of 59 non-repetitive poultry isolates were selected for investigation based on lactose fermentation on MacConkey agar and subsequent identification and confirmation as E. coli using chromogenic agar and uidA PCR. Kirby Bauer disc diffusion was used for susceptibility testing. For each antimicrobial agent, inhibition zone diameters were measured, and ECOFFs, CLSI and NRI bespoke breakpoints were used for resistance interpretation. Results: According to the interpretation of all breakpoints except ECOFFs, tetracycline resistance was significantly higher (TET) (67.8 -69.5 %), than those for ciprofloxacin (CIPRO) (18.6 -32.2 %), imipenem (IMI) (3.4 -35 %) and ceftazidime (CEF) (1.7 -45.8 %). Prevalence estimates of AMR using CLSI and NRI bespoke breakpoints did not differ for CEF (1.7 % CB and 1.7 % COWT), IMI (3.4 % CB and 4.0 % COWT) and TET (67.8 % CB and 69.5 % COWT). However, with ECOFFs, AMR estimates for CEF, IMI and CIP were significantly higher (45.8, 35.6 and 64.4 %, respectively; P<0.05). Across all the three breakpoints, resistance to ciprofloxacin varied significantly (32.2 % CB, 64.4 % ECOFFs and 18.6 % COWT, P<0.05). Conclusion: AMR interpretation is influenced by the breakpoint used, necessitating further standardization, especially for microbiological breakpoints, in order to harmonize outputs. The AMR ECOFF estimates in the present study were significantly higher compared to CLSI and NRI.

9.
Antibiotics (Basel) ; 11(3)2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-35326806

RESUMO

The emergence of antimicrobial-resistant bacteria is an enormous challenge to public health. Aeromonas hydrophila and Aeromonas veronii are opportunistic pathogens in fish. They exert tremendous adverse effects on aquaculture production, owing to their acquired antibiotic resistance. A few Clinical and Laboratory Standards Institute (CLSI) epidemiological cut-off values (ECVs) against Aeromonas spp. are available. We evaluated antimicrobial susceptibility by establishing 8 ECVs using two analytical methods, normalized resistance interpretation and ECOFFinder. We detected antimicrobial resistance genes in two motile Aeromonas spp. isolated from aquatic animals. Results showed that 89.2% of A. hydrophila and 75.8% of A. veronii isolates were non-wild types according to the oxytetracycline ECVCLSI and ECVNRI, respectively. The antimicrobial resistance genes included tetA, tetB, tetD, tetE, cat, floR, qnrA, qnrB, qnrS, strA-strB, and aac(6')-1b. The most common tet gene in Aeromonas spp. isolates was tetE, followed by tetA. Some strains carried more than one tet gene, with tetA-tetD and tetA-tetE found in A. hydrophila; however, tetB was not detected in any of the strains. Furthermore, 18.6% of A. hydrophila and 24.2% of A. veronii isolates showed presumptive multidrug-resistant phenotypes. The emergence of multidrug resistance among aquatic aeromonads suggests the spread of drug resistance and difficult to treat bacterial infections.

10.
Antibiotics (Basel) ; 9(12)2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33316982

RESUMO

Mycoplasma bovis is an important pathogen causing mostly pneumonia in calves and mastitis in dairy cattle. In the absence of an effective vaccine, antimicrobial therapy remains the main control measure. Antimicrobial use in veal calves is substantially higher than in conventional herds, but whether veal calves also harbor more resistant M. bovis strains is currently unknown. Therefore, we compared antimicrobial susceptibility test results of M. bovis isolates from different cattle sectors and genomic clusters. The minimum inhibitory concentration of nine antimicrobials was determined for 141 Belgian M. bovis isolates (29 dairy, 69 beef, 12 mixed, 31 veal farms), and was used to estimate the epidemiological cut-off. Acquired resistance was frequently observed for the macrolides, while no acquired resistance to oxytetracycline and doxycycline, minimal acquired resistance to florfenicol and tiamulin, and a limited acquired resistance to enrofloxacin was seen. M. bovis isolates from beef cattle or genomic cluster III had higher odds of being gamithromycin-resistant than those from dairy cattle or genomic clusters IV and V. In this study, no cattle industry could be identified as source of resistant M. bovis strains. A single guideline for antimicrobial use for M. bovis infections, with a small remark for gamithromycin, is likely sufficient.

11.
Front Microbiol ; 8: 503, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28400760

RESUMO

The importance of the role of environment in the dissemination of antimicrobial resistant bacteria is now well recognized. Thus, bacterial indicators to monitor the phenomena are required. The Aeromonas genus is autochthonous in the aquatic environment and easy to detect in any water type, such as freshwater, or wastewater. These microorganisms are also causing infections in humans and animals (including fish). Furthermore, as Aeromonas spp. is able to acquire antimicrobial resistance mechanisms, it is candidate for indicator bacteria to follow antimicrobial resistance dissemination in aquatic environments. Unfortunately, to date, interpretation criteria for Aeromonas spp. for antimicrobial susceptibility tests are scarce in the literature. No epidemiological cut-off values for Aeromonas are currently available at EUCAST to interpret Minimum Inhibitory Concentrations (MIC). The only interpretation criteria available are clinical breakpoints from CLSI that are adapted from Enterobacteriaceae. Based on the results of MIC distributions obtained for a collection of environmental isolates of Aeromonas, this study aimed at proposing tentative epidemiological cut-off values (COWT) for Aeromonas spp. assessing whether the genus is an acceptable level of definition. Thus, 233 isolates collected from 16 rivers were identified at species level using Maldi-Tof (Bruker). Eleven different species were identified, the most abundant were A. bestiarum (n = 54), A. salmonicida (n = 45), A. sobria (n = 41), and A. eucrenophila (n = 37). 96-well micro-plates containing different concentrations of 15 antimicrobials, namely cefotaxime, ceftazidime, chloramphenicol, colistin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, nalidixic acid, oxolinic acid, streptomycin, temocillin, tetracycline, and trimethoprim-sulfamethoxazole, were prepared. The broth micro-dilution method was used to determine the antimicrobial susceptibility of each isolate. The estimation of COWT values was satisfactory obtained at genus level for all antimicrobials except cefotaxime and erythromycin. This first step is an invitation for other research teams to increase the amount of antimicrobial resistance data collected. Then, robustness of our proposed provisional generic epidemiological cut-off values could be assessed by testing antimicrobial susceptibility of various Aeromonas collections.

12.
APMIS ; 124(12): 1023-1030, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27859688

RESUMO

The normalized resistance interpretation (NRI) method was developed in response to a call for a method to calibrate disc diffusion test results making inter-laboratory comparisons possible. The main use of NRI so far has been in individual laboratories, in medical and veterinary medicine and in the field of marine microbiology. The applications of NRI for disc diffusion tests are reviewed and, in addition, a detailed description of the calculation procedure is presented. NRI provides a fully objective method for ECOFF calculations of disc diffusion antimicrobial susceptibility test results.


Assuntos
Bactérias/efeitos dos fármacos , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão/métodos , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão/normas , Bactérias/classificação , Farmacorresistência Bacteriana
13.
APMIS ; 122(11): 1096-101, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24730430

RESUMO

Analysis of 163 disc diffusion data sets, 115 for bacterial species groups and 48 for types strains, published by EUCAST, was used to optimize the setting of the parameters of a standardized protocol for normalized resistance interpretation of these data. The standard deviations of the normalized distributions of these data sets, calculated using this standardized protocol, were shown to be independent of the means of their respective distributions. These standard deviations could, therefore, be used as a metric to quantify the precision of disc diffusion data sets. The median value of the standard deviations for 115 EUCAST data sets produced in multiple laboratory studies of bacterial species groups was 2.3 mm and that for the 48 EUCAST data sets produced in multiple laboratory studies of type strains was 1.5 mm. It is argued that this standardized method for estimating the precision of disc diffusion data provides a tool by which individual laboratories can assess the quality of the disc diffusion data they produce.


Assuntos
Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Padrões de Referência
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