scholarly journals Evidence for Extensive Resistance Gene Transfer amongBacteroides spp. and among Bacteroides and Other Genera in the Human Colon

2001 ◽  
Vol 67 (2) ◽  
pp. 561-568 ◽  
Author(s):  
N. B. Shoemaker ◽  
H. Vlamakis ◽  
K. Hayes ◽  
A. A. Salyers
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Dna Sequences ◽  
Human Colon ◽  
Bacillus Sphaericus ◽  
Erythromycin Resistance ◽  
Gram Positive ◽  
Gram Positive Bacteria

ABSTRACT Transfer of antibiotic resistance genes by conjugation is thought to play an important role in the spread of resistance. Yet virtually no information is available about the extent to which such horizontal transfers occur in natural settings. In this paper, we show that conjugal gene transfer has made a major contribution to increased antibiotic resistance in Bacteroides species, a numerically predominant group of human colonic bacteria. Over the past 3 decades, carriage of the tetracycline resistance gene, tetQ, has increased from about 30% to more than 80% of strains. Alleles oftetQ in different Bacteroides species, with one exception, were 96 to 100% identical at the DNA sequence level, as expected if horizontal gene transfer was responsible for their spread. Southern blot analyses showed further that transfer of tetQwas mediated by a conjugative transposon (CTn) of the CTnDOT type. Carriage of two erythromycin resistance genes, ermF andermG, rose from <2 to 23% and accounted for about 70% of the total erythromycin resistances observed. Carriage oftetQ and the erm genes was the same in isolates taken from healthy people with no recent history of antibiotic use as in isolates obtained from patients with Bacteroidesinfections. This finding indicates that resistance transfer is occurring in the community and not just in clinical environments. The high percentage of strains that are carrying these resistance genes in people who are not taking antibiotics is consistent with the hypothesis that once acquired, these resistance genes are stably maintained in the absence of antibiotic selection. Six recently isolated strains carriedermB genes. Two were identical to erm(B)-P fromClostridium perfringens, and the other four had only one to three mismatches. The nine strains with ermG genes had DNA sequences that were more than 99% identical to the ermG ofBacillus sphaericus. Evidently, there is a genetic conduit open between gram-positive bacteria, including bacteria that only pass through the human colon, and the gram-negative Bacteroidesspecies. Our results support the hypothesis that extensive gene transfer occurs among bacteria in the human colon, both within the genus Bacteroides and among Bacteroides species and gram-positive bacteria.

scholarly journals Molecular Analysis of Antibiotic Resistance Gene Clusters in Vibrio cholerae O139 and O1 SXT Constins

2001 ◽  
Vol 45 (11) ◽  
pp. 2991-3000 ◽  
Author(s):  
Bianca Hochhut ◽  
Yasmin Lotfi ◽  
Didier Mazel ◽  
Shah M. Faruque ◽  
Roger Woodgate ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Vibrio Cholerae ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Dna Sequences ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Gene Clusters ◽  
Vibrio Cholerae O139 ◽  
El Tor

ABSTRACT Many recent Asian clinical Vibrio cholerae E1 Tor O1 and O139 isolates are resistant to the antibiotics sulfamethoxazole (Su), trimethoprim (Tm), chloramphenicol (Cm), and streptomycin (Sm). The corresponding resistance genes are located on large conjugative elements (SXT constins) that are integrated into prfC on the V. cholerae chromosome. We determined the DNA sequences of the antibiotic resistance genes in the SXT constin in MO10, an O139 isolate. In SXTMO10, these genes are clustered within a composite transposon-like structure found near the element's 5′ end. The genes conferring resistance to Cm (floR), Su (sulII), and Sm (strA and strB) correspond to previously described genes, whereas the gene conferring resistance to Tm, designated dfr18, is novel. In some other O139 isolates the antibiotic resistance gene cluster was found to be deleted from the SXT-related constin. The El Tor O1 SXT constin, SXTET, does not contain the same resistance genes as SXTMO10. In this constin, the Tm resistance determinant was located nearly 70 kbp away from the other resistance genes and found in a novel type of integron that constitutes a fourth class of resistance integrons. These studies indicate that there is considerable flux in the antibiotic resistance genes found in the SXT family of constins and point to a model for the evolution of these related mobile elements.

scholarly journals Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria

2005 ◽  
Vol 43 (5) ◽  
pp. 2291-2302 ◽  
Author(s):  
V. Perreten ◽  
L. Vorlet-Fawer ◽  
P. Slickers ◽  
R. Ehricht ◽  
P. Kuhnert ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals Correlation between the Resistance Genotype Determined by Multiplex PCR Assays and the Antibiotic Susceptibility Patterns of Staphylococcus aureus andStaphylococcus epidermidis

2000 ◽  
Vol 44 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Francis Martineau ◽  
François J. Picard ◽  
Nicolas Lansac ◽  
Christian Ménard ◽  
Paul H. Roy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Multiplex Pcr ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Disk Diffusion ◽  
Erythromycin Resistance ◽  
Oxacillin Resistance ◽  
Pcr Assays

ABSTRACT Clinical isolates of Staphylococcus aureus (a total of 206) and S. epidermidis (a total of 188) from various countries were tested with multiplex PCR assays to detect clinically relevant antibiotic resistance genes associated with staphylococci. The targeted genes are implicated in resistance to oxacillin (mecA), gentamicin [aac(6′)-aph(2")], and erythromycin (ermA, ermB, ermC, andmsrA). We found a nearly perfect correlation between genotypic and phenotypic analysis for most of these 394 strains, showing the following correlations: 98% for oxacillin resistance, 100% for gentamicin resistance, and 98.5% for erythromycin resistance. The discrepant results were (i) eight strains found to be positive by PCR for mecA or ermC but susceptible to the corresponding antibiotic based on disk diffusion and (ii) six strains of S. aureus found to be negative by PCR for mecA or for the four erythromycin resistance genes targeted but resistant to the corresponding antibiotic. In order to demonstrate in vitro that the eight susceptible strains harboring the resistance gene may become resistant, we subcultured the susceptible strains on media with increasing gradients of the antibiotic. We were able to select cells demonstrating a resistant phenotype for all of these eight strains carrying the resistance gene based on disk diffusion and MIC determinations. The four oxacillin-resistant strains negative for mecA were PCR positive for blaZand had the phenotype of β-lactamase hyperproducers, which could explain their borderline oxacillin resistance phenotype. The erythromycin resistance for the two strains found to be negative by PCR is probably associated with a novel mechanism. This study reiterates the usefulness of DNA-based assays for the detection of antibiotic resistance genes associated with staphylococcal infections.

Characterization of multiresistance gene cfr(C) variants in Campylobacter from China

2019 ◽  
Vol 74 (8) ◽  
pp. 2166-2170 ◽  
Author(s):  
Dejun Liu ◽  
Xing Li ◽  
Weiwen Liu ◽  
Hong Yao ◽  
Zhihai Liu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Genomic Islands ◽  
Campylobacter Coli ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Novel Variants ◽  
The Usa ◽  
Variant Genes

Abstract Objectives To investigate the occurrence, the genetic environment and the functionality of novel variants of the MDR gene cfr(C) in Campylobacter from China. Methods A total of 370 Campylobacter isolates of porcine and chicken origin collected from three regions of China in 2015 were screened for cfr(C) by PCR. The phenotypes and genotypes of cfr(C)-positive isolates were investigated by antimicrobial susceptibility testing, PFGE, MLST, S1-PFGE, Southern blotting and WGS. Quantitative RT–PCR was used to compare the expression levels of the cfr(C) variants in their original isolate and clone constructs in Campylobacter jejuni NCTC 11168. Results Four (1.1%) porcine Campylobacter coli isolates were positive for cfr(C). They failed to show elevated MICs of phenicols. The deduced Cfr(C) sequences identified exhibited 2–6 amino acid changes compared with the original Cfr(C) reported in the USA. Cloning of the cfr(C) variant genes into C. jejuni NCTC 11168 resulted in ≥32-fold increases in the MICs of phenicols, indicating that the cfr(C) variant genes are functional. The cfr(C)-carrying isolates belonged to three genotypes and WGS analysis revealed the cfr(C) genes were chromosomally located in MDR genomic islands, which contained multiple antibiotic resistance genes of Gram-positive origin. Conclusions This study identified chromosomal cfr(C) genes in C. coli isolates from China. They appeared functionally dormant in the original isolates but were fully functional when cloned and expressed in C. jejuni. The cfr(C) genes were co-transferred with other antibiotic resistance genes, possibly from Gram-positive bacteria. These findings reveal new insights into the function and transmission of cfr(C) in Campylobacter.

scholarly journals Characterization of the Tn916-like Transposon Tn3872 in a Strain of Abiotrophia defectiva (Streptococcus defectivus) Causing Sequential Episodes of Endocarditis in a Child

2000 ◽  
Vol 44 (3) ◽  
pp. 790-793 ◽  
Author(s):  
Claire Poyart ◽  
Gilles Quesne ◽  
Philippe Acar ◽  
Patrick Berche ◽  
Patrick Trieu-Cuot
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Tetracycline Resistance Gene ◽  
Conjugative Transposons ◽  
Abiotrophia Defectiva

ABSTRACT Clinical blood isolates from three sequential episodes of endocarditis occurring over a 6-month period in a child with a malformative cardiopathy were investigated. All isolates identified asAbiotrophia defectiva were resistant to erythromycin-clindamycin and to tetracycline-minocycline, due to the presence of sequences homologous to the erythromycin resistance geneermB and to the tetracycline resistance genetet(M), respectively. These resistance genes were located on a chromosomally borne composite Tn916-related transposon. These results demonstrate the involvement of conjugative transposons in the dissemination of antibiotic resistance in the genusAbiotrophia.

scholarly journals Transfer of Antibiotic Resistance Genes from Gram-positive Bacterium to Gram-negative Bacterium

2020 ◽  
Author(s):  
Prasanth Manohar ◽  
Thamaraiselvan Shanthini ◽  
Bulent Bozdogan ◽  
Cecilia Stalsby Lundborg ◽  
Ashok J Tamhankar ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Poultry Litter ◽  
Pathogenic Bacterium ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
16S Rrna Analysis ◽  
Gram Negative ◽  
E Coli

AbstractThe emergence of antibiotic resistance due to uncontrolled use of antibiotics in non-humans, poses a major threat for treating bacterial infections in humans. Added to this is the possibility of transfer of resistance from Gram-positive bacteria to Gram-negative bacteria. Therefore, the possibility of resistance gene transfer from a non-human originated pathogenic bacterium to a pathogenic bacterium infecting humans needs evaluation. In this study, poultry litter samples collected from Tamil Nadu, India were screened for the presence of meropenem- and cefotaxime-resistant Staphylococcus sciuri. Standard microbiological techniques and 16S rRNA analysis were used to confirm S. sciuri. In the resistant isolates, resistance genes such as blaNDM-1, blaOXA-48-like, blaKPC, blaVIM, blaIMP and blaCTX-M were screened. Transconjugation studies were performed using donor, S. sciuri and recipient, E. coli AB1157 (Strr). A total of 26 meropenem-resistant and 24 cefotaxime resistant S. sciuri were isolated from poultry litter samples. The presence of blaNDM-1 (n=2), blaIMP (n=8), blaCTX-M-9 (n=5) and blaCTX-M-2 (n=1) was detected. Transconjugation results confirmed that S. sciuri carrying plasmid-borne resistance gene blaNDM-1 conjugated to E. coli AB1157. The transferability of resistance genes from S. sciuri to E. coli could be another possible reason for spread of antibiotic-resistant bacteria in humans.

scholarly journals Early Inoculation of Microbial Suspension in Suckling Piglets Affects the Transmission of Maternal Microbiota and the Associated Antibiotic Resistance Genes

2020 ◽  
Vol 8 (10) ◽  
pp. 1576
Author(s):  
Caroline S. Achard ◽  
Veronique Dupouy ◽  
Laurent Cauquil ◽  
Nathalie Arpaillange ◽  
Alain Bousquet-Melou ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Erythromycin Resistance ◽  
Tetracycline Resistance Gene ◽  
Microbial Species ◽  
Gut Colonization ◽  
16S Rna

Antibiotic resistance of microbes thriving in the animal gut is a growing concern for public health as it may serve as a hidden reservoir for antibiotic resistance genes (ARGs). We compared 16 control piglets to 24 piglets fed for 3 weeks with S1 or S2 fecal suspensions from two sows that were not exposed to antibiotics for at least 6 months: the first suspension decreased the erythromycin resistance gene ermB and the aminoglycoside phosphotransferase gene conferring resistance to kanamycine (aphA3), while the second decreased the tetracycline resistance gene tetL, with an unexpected increase in ARGs. Using 16S RNA sequencing, we identified microbial species that are likely to carry ARGs, such as the lincosamide nucleotidyltransferase lnuB, the cephalosporinase cepA, and the tetracycline resistance genes tetG and tetM, as well as microbes that never co-exist with the tetracycline resistance gene tetQ, the erythromycin resistance gene ermG and aphA3. Since 73% of the microbes detected in the sows were not detected in the piglets at weaning, a neutral model was applied to estimate whether a microbial species is more important than chance would predict. This model confirmed that force-feeding modifies the dynamics of gut colonization. In conclusion, early inoculation of gut microbes is an interesting possibility to stimulate gut microbiota towards a desirable state in pig production, but more work is needed to be able to predict which communities should be used.

scholarly journals Ontology-Aware Deep Learning Enables Novel Antibiotic Resistance Gene Discovery Towards Comprehensive Profiling of ARGs

2021 ◽  
Author(s):  
Yuguo Zha ◽  
Cheng Chen ◽  
Qihong Jiao ◽  
Xiaomei Zeng ◽  
Xuefeng Cui ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Deep Learning ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Gene ◽  
Antibiotic Resistance Genes ◽  
Oral Microbiome ◽  
Gram Positive Bacteria ◽  
Wet Lab ◽  
Deep Learning Model

Antibiotic resistance genes (ARGs) have emerged in pathogens and spread faster than expected, arousing a worldwide concern. Current methods are suitable mainly for the discovery of close homologous ARGs and have limited utility for discovery of novel ARGs, thus rendering the profiling of ARGs incomprehensive. Here, an ontology-aware deep learning model, ONN4ARG (http://onn4arg.xfcui.com/), is proposed for the discovery of novel ARGs based on multi-level annotations. Experiments based on billions of candidate microbial genes collected from various environments show the superiority of ONN4ARG in comprehensive ARG profiling. Enrichment analyses show that ARGs are both environment-specific and host-specific. For example, resistance genes for rifamycin, which is an important antibacterial agent active against gram-positive bacteria, are enriched in Actinobacteria and in soil environment. Case studies verified ONN4ARG's ability for novel ARG discovery. For example, a novel streptomycin resistance gene was discovered from oral microbiome samples and validated through wet-lab experiments. ONN4ARG provides a complete picture of the prevalence of ARGs in microbial communities as well as guidance for detection and reduction of the spread of resistance genes.

Sign in / Sign up

Export Citation Format

Share Document