scholarly journals Comparative analysis of Bacillus cereus group isolates' resistance using disk diffusion and broth microdilution and the correlation between resistance phenotypes and genotypes

2021 ◽  
Author(s):  
Emma Mills ◽  
Erin Sullivan ◽  
Jasna Kovac
Keyword(s):  
Antimicrobial Resistance ◽  
Bacillus Cereus ◽  
Resistance Genes ◽  
Disk Diffusion ◽  
Broth Microdilution ◽  
Beta Lactam ◽  
Phenotypic Resistance ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Disk Diffusion Assay

A collection of 85 Bacillus cereus group isolates were screened for phenotypic resistance to nine antibiotics using disk diffusion and broth microdilution. The broth microdilution antimicrobial results were interpreted using the CLSI M45 breakpoints for Bacillus spp. Due to the lack of Bacillus spp. disk diffusion breakpoints, the results obtained with the disk diffusion assay were interpreted using the CLSI M100 breakpoints for Staphylococcus spp. We identified significant (p < 0.05) discrepancies in resistance interpretation between the two methods for ampicillin, gentamicin, rifampicin, tetracycline, and trimethoprim/sulfamethoxazole. Antimicrobial resistance genes were detected using unassembled and assembled whole-genome sequences with Ariba and Abricate, respectively, to assess the sensitivity and specificity for predicting phenotypic resistance based on the presence of antimicrobial resistance genes. We found antimicrobial resistance gene presence to be a poor indicator for phenotypic resistance, calling for further investigation of mechanisms underlying antimicrobial resistance in the B. cereusgroup. Genes with poor sensitivity and/or specificity, as determined based on broth microdilution results included rph(rifampicin, 0%, 95%), mphgenes (erythromycin, 0%, 96%), and all vangenes (vancomycin, 100%, 35%). However, Bc(ampicillin, 64%, 100%) andtet genes (tetracycline, 67%, 100%) were highly specific, albeit moderately sensitive indicators of phenotypic resistance based on broth microdilution results. Only beta-lactam resistance genes (Bc, BcII, and blaTEM) were highly sensitive (94%) and specific (100%) markers of resistance to ceftriaxone based on the disk diffusion results, providing further evidence of these beta-lactams' role in nonsusceptibility of Bacillus cereus group isolates to ceftriaxone.

scholarly journals Associations between Antimicrobial Resistance Phenotypes, Antimicrobial Resistance Genes, and Virulence Genes of Fecal Escherichia coli Isolates from Healthy Grow-Finish Pigs

2009 ◽  
Vol 75 (5) ◽  
pp. 1373-1380 ◽  
Author(s):  
Leigh B. Rosengren ◽  
Cheryl L. Waldner ◽  
Richard J. Reid-Smith
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Large Scale ◽  
Virulence Genes ◽  
Antimicrobial Use ◽  
Phenotypic Resistance ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene

ABSTRACT Escherichia coli often carries linked antimicrobial resistance genes on transmissible genetic elements. Through coselection, antimicrobial use may select for unrelated but linked resistance or virulence genes. This study used unconditional statistical associations to investigate the relationships between antimicrobial resistance phenotypes and antimicrobial resistance genes in 151 E. coli isolates from healthy pigs. Phenotypic resistance to each drug was significantly associated with phenotypic resistance to at least one other drug, and every association found that the probability of observing the outcome resistance was increased by the presence of the predictor resistance. With one exception, each statistical association that was identified between a pair of resistance genes had a corresponding significant association identified between the phenotypes mediated by those genes. This suggests that associations between resistance phenotypes might predict coselection. If this hypothesis is confirmed, evaluation of the associations between resistance phenotypes could improve our knowledge of coselection dynamics and provide a cost-effective way to evaluate existing data until large-scale genotypic data collection becomes feasible. This could enable policy makers and users of antimicrobials to consider coselection in antimicrobial use decisions. This study also considered the unconditional relationships between resistance and virulence genes in E. coli from healthy pigs (aidA-1, eae, elt, estA, estB, fedA1, stx1, and stx2). Positive statistical associations would suggest that antimicrobial use may select for virulence in bacteria that may contaminate food or cause diarrhea in pigs. Fortunately, the odds of detecting a virulence gene were rarely increased by the presence of an antimicrobial resistance gene. This suggests that on-farm antimicrobial use did not select for the examined virulence factors in E. coli carried by this population of healthy pigs.

scholarly journals Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

2014 ◽  
Vol 80 (12) ◽  
pp. 3656-3666 ◽  
Author(s):  
Basanta Kumar Biswal ◽  
Ramzi Khairallah ◽  
Kareem Bibi ◽  
Alberto Mazza ◽  
Ronald Gehr ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Peracetic Acid ◽  
Content Type ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Municipal Wastewaters ◽  
The Impact

ABSTRACTWastewater discharges may increase the populations of pathogens, includingEscherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenicEscherichia coli(UPEC), the most abundantE. colipathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766E. coliisolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters.

Formula-fed and Clostridium difficile infected neonatal piglets carry a highly diverse and abundant set of antimicrobial resistance genes

2020 ◽  
Author(s):  
Robert Pieper ◽  
Temesgen Dadi ◽  
Lukasz Grzeskowiak ◽  
Laura Pieper ◽  
Britta Siegmund ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Microbial Colonization ◽  
Metagenomic Data ◽  
Neonatal Piglets ◽  
Gut Colonization ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Genes Encoding

Abstract Background: Clostridium difficile infection (CDI) is an increasing zoonotic health threat and has also been documented as a cause of enteritis outbreaks in neonatal pigs. Furthermore, CDI in neonatal piglets cause changes in microbial gut colonization. We hypothesized that an imbalanced microbial colonization in piglets with CDI could be associated with an altered abundance of antimicrobial resistance genes. Results: We analyzed fecal metagenomic data of lactating sows (S), their piglets during suckling (SP), the same piglets two weeks after weaning (WP), 5-day old artificially reared and formula-fed siblings (FP) and FP infected with C. difficile (FP-CD) for microbiota composition and antimicrobial resistance gene abundance. FP and FP-CD piglets had an immature-type microbiota and increased abundance of antimicrobial resistance genes. A co-occurrence of genes encoding for resistance against aminoglycosides (e.g. aph(3”)-lb, aph(6)-ld, ant(2”)-la), β-lactams (blaCTX-M, blaTEM), fluoroquinolones (pat(A) macrolides (mph(A)), sulfonamides (sul1, sul2), polypeptides (e.g. pmrB, pmrC, arnA, bac(A)) and tetracyclines (e.g. tet(A-D),) was observed. Conclusion: Increased abundance of antimicrobial resistance genes in formula feeding and concomitant CDI may be associated with therapeutic resistance later in life and warrant further studies.

scholarly journals Antimicrobial resistance gene prevalence in a population of patients with advanced dementia is related to specific pathobionts

2019 ◽  
Author(s):  
Aislinn D. Rowan-Nash ◽  
Rafael Araos ◽  
Erika M.C. D’Agata ◽  
Peter Belenky
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
High Frequency ◽  
Multidrug Resistant ◽  
Advanced Dementia ◽  
Dementia Patients ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Multidrug Resistant Organisms

ABSTRACTBackgroundThe issue of antimicrobial resistance continues to grow worldwide, and long-term care facilities are significant reservoirs of antimicrobial-resistant organisms, in part due to high frequency of antimicrobial use. Patients with advanced dementia are particularly vulnerable to multidrug-resistant organism acquisition and antimicrobial overuse, which has negative consequences for the gut microbiome and can contribute to the selection and propagation of antimicrobial resistance genes. In this study, we longitudinally examined a group of advanced dementia patients treated with the fluoroquinolone antimicrobial levofloxacin, finding a correlation between abundance of pathogens and antimicrobial resistance genes, which we confirmed in a larger cohort of subjects with advanced dementia.ResultsWe observed significant inter- and intra-subject heterogeneity in the composition of the microbiota of the longitudinal levofloxacin cohort, suggesting temporal instability. Within this dataset, we did not find significant impacts of levofloxacin on the diversity, composition, function, or resistome of the gut microbiota of this population. However, we were able to link the antimicrobial resistance gene burden in a sample with the relative abundance of several pathobionts – particularly Escherichia coli, Proteus mirabilis, and Enterococcus faecalis, as well as less-prevalent species including Providencia stuartii and Staphylococcus haemolyticus. Furthermore, we used metagenomic assembly and binning to demonstrate that these species had higher genomic resistance gene levels than common gut commensals, and we were able to predict antimicrobial resistance gene burden from the relative abundances of these species in a separate, larger cohort from the same population.ConclusionsWe found that the relative abundances of several pathobionts were correlated with and were even predictive of the level of antimicrobial resistance genes in corresponding samples, and that these species carried high levels of resistances genes in their assembled genomes. In order to test this observation, we utilized a larger metagenomics dataset from a similar population and confirmed the association between pathobiont abundance and antimicrobial resistance genes. Given the high frequency with which these species were found at high levels in this population and the underlying vulnerability to infection with multidrug resistant organisms of advanced dementia patients, attention to microbial blooms of these species may be warranted. Additionally, in this study, we were able to utilize genomic assembly from metagenomic data to more definitively associate antimicrobial resistance gene levels with specific assembled species; as this technology continues to develop, assembly could prove to be a valuable method to monitor both specific resistance genes and blooms of multidrug-resistant organisms.

scholarly journals Occurrence of Virulence and Antimicrobial Resistance Genes in Escherichia coli Isolates from Different Aquatic Ecosystems within the St. Clair River and Detroit River Areas

2006 ◽  
Vol 73 (2) ◽  
pp. 477-484 ◽  
Author(s):  
Katia Hamelin ◽  
Guillaume Bruant ◽  
Abdel El-Shaarawi ◽  
Stephen Hill ◽  
Thomas A. Edge ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Surface Waters ◽  
Aquatic Ecosystems ◽  
Urban Site ◽  
Detroit River ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene

ABSTRACT Although the number of Escherichia coli bacteria in surface waters can differ greatly between locations, relatively little is known about the distribution of E. coli pathotypes in surface waters used as sources for drinking or recreation. DNA microarray technology is a suitable tool for this type of study due to its ability to detect high numbers of virulence and antimicrobial resistance genes simultaneously. Pathotype, phylogenetic group, and antimicrobial resistance gene profiles were determined for 308 E. coli isolates from surface water samples collected from diverse aquatic ecosystems at six different sites in the St. Clair River and Detroit River areas. A higher frequency (48%) of E. coli isolates possessing virulence and antimicrobial resistance genes was observed in an urban site located downstream of wastewater effluent outfalls than in the other examined sites (average of 24%). Most E. coli pathotypes were extraintestinal pathogenic E. coli (ExPEC) pathotypes and belonged to phylogenetic groups B2 and D. The ExPEC pathotypes were found to occur across all aquatic ecosystems investigated, including riverine, estuarine, and offshore lake locations. The results of this environmental study using DNA microarrays highlight the widespread distribution of E. coli pathotypes in aquatic ecosystems and the potential public health threat of E. coli pathotypes originating from municipal wastewater sources.

scholarly journals Diverse commensal E. coli clones and plasmids disseminate antimicrobial resistance genes in domestic animals and children in a semi-rural community in Ecuador

2019 ◽  
Author(s):  
Liseth Salinas ◽  
Paúl Cárdenas ◽  
Timothy J. Johnson ◽  
Karla Vasco ◽  
Jay Graham ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Rural Community ◽  
Resistance Genes ◽  
Domestic Animals ◽  
Drug Resistant ◽  
Phenotypic Resistance ◽  
E Coli ◽  
Antimicrobial Resistance Genes ◽  
Resistance Patterns

ABSTRACTThe increased prevalence of antimicrobial resistance (AMR) among Enterobacteriaceae has had major clinical and economic impacts in human medicine. Many of the multi-drug resistant (MDR) Enterobacteriaceae found in humans are community-acquired and linked to food animals (i.e. livestock raised for meat and dairy products). In this study, we examined whether numerically dominant, commensal Escherichia coli strains from humans (n=63 isolates) and domestic animals (n=174 isolates) in the same community and with matching phenotypic AMR patterns, were clonally related or shared the same plasmids. We identified 25 multi-drug resistant isolates (i.e. resistant to 3 or more antimicrobial classes) that shared identical phenotypic resistance patterns. We then investigated the diversity of E. coli clones, AMR genes and plasmids carrying the AMR genes using conjugation, replicon typing and whole genome sequencing. None of the MDR E. coli isolates (from children and domestic animals) analyzed were clonal. While the majority of isolates shared the same antimicrobial resistance genes and replicons, DNA sequencing indicated that these genes and replicons were found on different plasmid structures. Our findings suggest that nonclonal resistance gene dissemination is common in this community and that diverse plasmids carrying AMR genes presents a significant challenge for understanding the movement of AMR in a community.IMPORTANCEEven though Escherichia coli strains may share nearly identical AMR profiles, AMR genes, and overlap in space and time, the diversity of clones and plasmids challenges to research that aims to identify sources of AMR. Horizontal gene transfer appears to play a much larger role than clonal expansion in the spread of AMR in the community.

scholarly journals Raw milk for human consumption may carry antimicrobial resistance genes

2019 ◽  
Author(s):  
Adrienn Gréta Tóth ◽  
István Csabai ◽  
Eszter Krikó ◽  
Dóra Tőzsér ◽  
Gergely Maróti ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Raw Milk ◽  
Human Consumption ◽  
Peptide Antibiotics ◽  
Animal Products ◽  
Milk Samples ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Resistant Strains

AbstractBackgroundThe increasing prevalence of antimicrobial resistance (AMR) is a significant threat to global health. The widespread use of antibiotics is increasingly shortening the time it takes for resistant strains to develop. More and more multi-drug-resistant bacterial strains cause life-threatening infections and the death of tens of thousands of people each year. Beyond disease control animals are often given antibiotics for growth promotion or increased feed efficiency, which further increase the chance of the development of multi-resistant strains. After the consumption of unprocessed animal products, these strains may meet the human bacteriota. Among the foodborne and the human populations, antimicrobial resistance genes (ARGs) may be shared by horizontal gene transfer. This study aims to test the presence of antimicrobial resistance genes in milk metagenome, investigate their genetic position and their linkage to mobile genetic elements.ResultsWe have analyzed raw milk samples from public markets sold for human consumption. The milk samples contained genetic material from various bacterial species and the detailed analysis uncovered the presence of several antimicrobial resistance genes. The samples contained complete ARGs influencing the effectiveness of acridine dye, cephalosporin, cephamycin, fluoroquinolone, penam, peptide antibiotics and tetracycline. One of the ARGs, PC1 beta-lactamase may also be a mobile element that facilitates the transfer of resistance genes to other bacteria, e.g. to the ones living in the human gut.ConclusionBesides the animal products’ antibiotic residuals, their potentially transmissible antimicrobial resistance gene content may also contribute to the development of human pathogenic bacteria’s antimicrobial resistance.

scholarly journals Antimicrobial resistance genes and bacterial diversity in sediments of Guandu River, Brazil

2021 ◽  
Vol 12 (4) ◽  
pp. 116-123
Author(s):  
Gustavo Souza Lima Sant'Anna ◽  
José Maurício Fajardo da Cunha ◽  
Juliana Ferreira Nunes ◽  
Isabel Arjonas Fernandes Avila ◽  
João Vitor da Silva Gonçalves ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
River Sediments ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Temperate Climate ◽  
Beta Lactam ◽  
M Gene ◽  
Antimicrobial Resistance Genes ◽  
Water Catchment

Rivers provide essential water resources for humans. However, appear to be reservoirs of antimicrobial-resistant genes and dispersal routes of resistant pathogens because human activities promptly influence them. Sediments are the most propitious substrates for bacteria survival and can act as an antimicrobial reservoir. Three sediment samples were collected upstream of the water catchment point of the Guandu Water Treatment Plant (ETA Guandu) to evaluate microbial diversity and antimicrobial resistance genes to sulfonamide (sul1, sul2), tetracycline (tetA, tetB) and beta-lactam (blaCTX-M, blaoxa24 and blaoxa58) by PCR. The most abundant phylum in all samples was Proteobacteria, which was also the most dominant in sediments presenting a pattern already reported in the literature for diversity in tropical and temperate climate rivers. Sulfonamide resistance genes were detected in all samples. The blaCTX-M gene was detected only in one sample, and tetA, tetB, blaoxa24 and blaoxa58 genes were not found in any sample. The presence of antimicrobial resistance genes sul1, sul2, and blaCTX-M indicate that sediments can act as a reservoir of resistance. These findings will provide new data about the bacterial community and antimicrobial resistance genes in Brazilians river sediments.

scholarly journals Microbiome and Antimicrobial Resistance Gene Dynamics in International Travelers

2018 ◽  
Author(s):  
Charles Langelier ◽  
Michael Graves ◽  
Katrina Kalantar ◽  
Saharai Caldera ◽  
Robert Durrant ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Antimicrobial Resistance ◽  
Gut Microbiota ◽  
Microbial Communities ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antimicrobial Resistance Genes ◽  
Antimicrobial Resistance Gene ◽  
Global Exchange ◽  
Generation Sequencing

AbstractWe engaged metagenomic next generation sequencing to longitudinally assess the gut microbiota and antimicrobial resistomes of international travelers to understand global exchange of resistant organisms. Travel resulted in an increase in antimicrobial resistance genes and a greater proportion of Escherichia species within gut microbial communities without impacting diversity.

scholarly journals Antimicrobial Resistance Genes in Enterotoxigenic Escherichia coli O149:K91 Isolates Obtained over a 23-Year Period from Pigs

2003 ◽  
Vol 47 (10) ◽  
pp. 3214-3221 ◽  
Author(s):  
Christine Maynard ◽  
John M. Fairbrother ◽  
Sadjia Bekal ◽  
François Sanschagrin ◽  
Roger C. Levesque ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Antimicrobial Agents ◽  
Enterotoxigenic Escherichia Coli ◽  
Genotypic Resistance ◽  
Class 1 Integron ◽  
Phenotypic Resistance ◽  
Antimicrobial Resistance Genes

ABSTRACT A total of 112 Escherichia coli O149:K91 strains isolated from pigs with diarrhea in Quebec, Canada, between 1978 and 2000 were characterized for their genotypic antimicrobial resistance profiles. Tests for resistance to 10 antimicrobial agents were conducted. Resistance to tetracycline and sulfonamides was found to be the most frequent, but resistance to cefotaxime and ceftiofur was absent. An increase in the number of isolates resistant to at least three antimicrobials was observed over time. The distribution of 28 resistance genes covering six antimicrobial families (beta-lactams, aminoglycosides, phenicols, tetracycline, trimethoprim, and sulfonamides) was assessed by colony hybridization. Significant differences in the distributions of tetracycline [tet(A), tet(B), tet(C)], trimethoprim (dhfrI, dhfrV, dhfrXIII), and sulfonamide (sulI, sulII) resistance genes were observed during the study period (1978 to 2000). Sixty percent of the isolates possessed a class 1 integron, illustrating the importance of integrons in the epidemiology of antibiotic resistance in E. coli strains from pigs. Amplification of the integron's variable region resulted in four distinct fragments of 1, 1.3, 1.6, and 1.8 kb, with the 1.6- and 1.8-kb fragments appearing only during the last half of the study period. Examination of linkages among the different resistance genes showed a variety of positive and negative associations. Association analysis of isolates divided into two groups, those isolated between 1978 and 1989 and those isolated between 1990 and 2000, revealed the appearance of new positive resistance gene associations. Our genotypic resistance analyses of ETEC isolates from pigs indicate that many of the antibiotic resistance genes behind phenotypic resistance are not static but, rather, are in a state of flux driven by various selection forces such as the use of specific antimicrobials.

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