scholarly journals Characteristics of antibiotic resistant strains of Vibrio cholerae carrying SXT type integrative conjugative elements

2014 ◽  
Vol 19 (3) ◽  
pp. 34-39
Author(s):  
M. V Podshivalova ◽  
Yu. A Kuzyutina ◽  
I. B Zakharova ◽  
Ya. A Lopasteyskaya ◽  
D. V Viktorov

In the paper there is presented a characteristics of antibiotic-resistant strains of Vibrio cholerae, isolated in the Volgograd region during the period of 1980-2000. There were studied cultural and morphological properties of the isolates, their biochemical activity, resistance to antibiotics of different classes, there was performed the detection of virulence genes and sequences of transmissible SXT-element. There was demonstrated the presence of different types of SXT in the content of the genome of the examined strains - SXT MO10 element with cluster of the antibiotic resistance gene sulII-strB-dfr18, SXT ET element carrying the sequences sulII dfrA1, and not having a resistance gene to aminoglycosides strB, and SXT S element with deleted cluster of antibiotic resistance genes.

2017 ◽  
Vol 16 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Nusrat Nahar ◽  
Ridwan Bin Rashid

Vibrio cholerae has long been reported as an important cause of death in developing countries. The study detected the virulence and antibiotic resistance gene of eight V. cholerae isolates through in silico tools. Cholera toxins, ctxA and ctxB were found in six isolates (75%). Seventy-five percent isolates were also found to be positive for zonula occludens toxin, zot which is known to increase the permeability by altering the tight junction of the small intestine. Accessory cholera enterotoxin ace, responsible for fluid accumulation, was detected in four V. cholerae strains. Seven isolates (87.5%) were positive for toxin-coregulated pilus, tcp which helps the bacteria to adhere to gut mucosa. Both ompW and toxR genes were found in 87.5% of the isolates. Twenty-five percent isolates harboured strA, strB, sulII, dfrA1, floR genes and SXT element demonstrating that they were multidrug-resistant (MDG) bacterium. One isolate was found to be positive for tetA gene while no erythromycin resistance gene, ermA and ermB was found. Virulence genes were found in all genotypes indicating that their distribution was not genotypeoriented while genotype 2 harboured no antibiotic resistance genes. This data helps to predict virulence genes associated with cholera and also demonstrates the presence of antibiotic resistance genes. Bacteria acquired the antibiotic resistance gene through natural process which cannot be stopped. So by analyzing the resistance pattern we can choose appropriate antibiotics. In silico study helps us to predict the antibiotic resistant genotypes and can easily identify antibiotic resistant strains which help us to treat cholera infections and reduce the morbidity and mortality rate of the infected individuals.Dhaka Univ. J. Pharm. Sci. 16(1): 77-85, 2017 (June)


2001 ◽  
Vol 45 (11) ◽  
pp. 2991-3000 ◽  
Author(s):  
Bianca Hochhut ◽  
Yasmin Lotfi ◽  
Didier Mazel ◽  
Shah M. Faruque ◽  
Roger Woodgate ◽  
...  

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.


2000 ◽  
Vol 44 (5) ◽  
pp. 1315-1321 ◽  
Author(s):  
Anders Dalsgaard ◽  
Anita Forslund ◽  
Oralak Serichantalergs ◽  
Dorthe Sandvang

ABSTRACT In this study, 176 clinical and environmental Vibrio cholerae strains of different O serotypes isolated in Thailand from 1982 to 1995 were selected and studied for the presence of class 1 integrons, a new group of genetic elements which carry antibiotic resistance genes. Using PCR and DNA sequencing, we found that 44 isolates contained class 1 integrons harboring the aadB,aadA2, blaP1, dfrA1, anddfrA15 gene cassettes, which encode resistance to gentamicin, kanamycin, and tobramycin; streptomycin and spectinomycin; β-lactams; and trimethoprim, respectively. Each cassette array contained only a single antibiotic resistance gene. Although resistance genes in class 1 integrons were found in strains from the same epidemic, as well as in unrelated non-O1, non-O139 strains isolated from children with diarrhea, they were found to encode only some of the antibiotic resistance expressed by the strains. Serotype O139 strains did not contain class 1 integrons. However, the appearance and disappearance of the O139 serotype in the coastal city Samutsakorn in 1992 and 1993 were associated with the emergence of a distinct V. cholerae O1 strain which contained the aadA2resistance gene cassette. A 150-kb self-transmissible plasmid found in three O1 strains isolated in 1982 contained the aadB gene cassette. Surprisingly, several strains harbored two integrons containing different cassettes. Thus, class 1 integrons containing various resistance gene cassettes are distributed among differentV. cholerae O serotypes of mainly clinical origin in Thailand.


Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 230
Author(s):  
Shan Wan ◽  
Min Xia ◽  
Jie Tao ◽  
Yanjun Pang ◽  
Fugen Yu ◽  
...  

In this study, we used a metagenomic approach to analyze microbial communities, antibiotic resistance gene diversity, and human pathogenic bacterium composition in two typical landfills in China. Results showed that the phyla Proteobacteria, Bacteroidetes, and Actinobacteria were predominant in the two landfills, and archaea and fungi were also detected. The genera Methanoculleus, Lysobacter, and Pseudomonas were predominantly present in all samples. sul2, sul1, tetX, and adeF were the four most abundant antibiotic resistance genes. Sixty-nine bacterial pathogens were identified from the two landfills, with Klebsiella pneumoniae, Bordetella pertussis, Pseudomonas aeruginosa, and Bacillus cereus as the major pathogenic microorganisms, indicating the existence of potential environmental risk in landfills. In addition, KEGG pathway analysis indicated the presence of antibiotic resistance genes typically associated with human antibiotic resistance bacterial strains. These results provide insights into the risk of pathogens in landfills, which is important for controlling the potential secondary transmission of pathogens and reducing workers’ health risk during landfill excavation.


BMC Genomics ◽  
2019 ◽  
Vol 20 (S10) ◽  
Author(s):  
Haobin Yao ◽  
Siu-Ming Yiu

Abstract Background Identification of antibiotic resistance genes from environmental samples has been a critical sub-domain of gene discovery which is directly connected to human health. However, it is drawing extraordinary attention in recent years and regarded as a severe threat to human health by many institutions around the world. To satisfy the needs for efficient ARG discovery, a series of online antibiotic resistance gene databases have been published. This article will conduct an in-depth analysis of CARD, one of the most widely used ARG databases. Results The decision model of CARD is based the alignment score with a single ARG type. We discover the occasions where the model is likely to make false prediction, and then propose an optimization method on top of the current CARD model. The optimization is expected to raise the coherence with BLAST homology relationships and improve the confidence for identification of ARGs using the database. Conclusions The absence of public recognized benchmark makes it challenging to evaluate the performance of ARG identification. However, possible wrong predictions and methods for resolving the problem can be inferred by computational analysis of the identification method and the underlying reference sequences. We hope our work can bring insight to the mission of precise ARG type classifications.


2020 ◽  
Vol 22 (2) ◽  
pp. 418-429 ◽  
Author(s):  
Jingyu Wang ◽  
Minghao Sui ◽  
Hongwei Li ◽  
Bojie Yuan

Ultraviolet disinfection could effectively inactivate the antibiotic resistant bacterium vancomycin resistant Enterococcus faecalis, but had a limited removal efficiency for the antibiotic resistance gene–vanB gene.


2012 ◽  
Vol 56 (9) ◽  
pp. 4703-4706 ◽  
Author(s):  
Jennifer L. Cottell ◽  
Mark A. Webber ◽  
Laura J. V. Piddock

ABSTRACTThe treatment of infections caused by antibiotic-resistant bacteria is one of the great challenges faced by clinicians in the 21st century. Antibiotic resistance genes are often transferred between bacteria by mobile genetic vectors called plasmids. It is commonly believed that removal of antibiotic pressure will reduce the numbers of antibiotic-resistant bacteria due to the perception that carriage of resistance imposes a fitness cost on the bacterium. This study investigated the ability of the plasmid pCT, a globally distributed plasmid that carries an extended-spectrum-β-lactamase (ESBL) resistance gene (blaCTX-M-14), to persist and disseminate in the absence of antibiotic pressure. We investigated key attributes in plasmid success, including conjugation frequencies, bacterial-host growth rates, ability to cause infection, and impact on the fitness of host strains. We also determined the contribution of theblaCTX-M-14gene itself to the biology of the plasmid and host bacterium. Carriage of pCT was found to impose no detectable fitness cost on various bacterial hosts. An absence of antibiotic pressure and inactivation of the antibiotic resistance gene also had no effect on plasmid persistence, conjugation frequency, or bacterial-host biology. In conclusion, plasmids such as pCT have evolved to impose little impact on host strains. Therefore, the persistence of antibiotic resistance genes and their vectors is to be expected in the absence of antibiotic selective pressure regardless of antibiotic stewardship. Other means to reduce plasmid stability are needed to prevent the persistence of these vectors and the antibiotic resistance genes they carry.


2002 ◽  
Vol 184 (15) ◽  
pp. 4259-4269 ◽  
Author(s):  
John W. Beaber ◽  
Bianca Hochhut ◽  
Matthew K. Waldor

ABSTRACT SXT is representative of a family of conjugative-transposon-like mobile genetic elements that encode multiple antibiotic resistance genes. In recent years, SXT-related conjugative, self-transmissible integrating elements have become widespread in Asian Vibrio cholerae. We have determined the 100-kb DNA sequence of SXT. This element appears to be a chimera composed of transposon-associated antibiotic resistance genes linked to a variety of plasmid- and phage-related genes, as well as to many genes from unknown sources. We constructed a nearly comprehensive set of deletions through the use of the one-step chromosomal gene inactivation technique to identify SXT genes involved in conjugative transfer and chromosomal excision. SXT, unlike other conjugative transposons, utilizes a conjugation system related to that encoded by the F plasmid. More than half of the SXT genome, including the composite transposon-like structure that contains its antibiotic resistance genes, was not required for its mobility. Two SXT loci, designated setC and setD, whose predicted amino acid sequences were similar to those of the flagellar regulators FlhC and FlhD, were found to encode regulators that activate the transcription of genes required for SXT excision and transfer. Another locus, designated setR, whose gene product bears similarity to lambdoid phage CI repressors, also appears to regulate SXT gene expression.


2019 ◽  
Author(s):  
Evelyn Loo ◽  
Amanda Zain ◽  
Gaik Chin Yap ◽  
Rikky W Purbojati ◽  
Daniela I Drautz-Moses ◽  
...  

Abstract Background: The rapid spread of multidrug- resistant pathogenic bacteria is a worldwide public health concern. Given the high carriage rate of extended spectrum beta-lactamase (ESBL)- producing Enterobacteriaceae in Asia, we aimed to evaluate community prevalence and dynamics by studying the longitudinal changes in antibiotic resistance gene (ARG) profiles and prevalence of ESBL-producing E coli and K. pneumoniae in the intestinal microbiome of infants participating in the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) study, a longitudinal cohort study of pregnant women and their infants. Methods: We analysed the antibiotic resistance genes profile in the first year of life among 75 infants who had stool samples collected at multiple timepoints using metagenomics. Results: The mean number of ARGs per infant increased with age. The most common ARGs identified confer resistance to aminoglycoside, beta-lactam, macrolide and tetracycline antibiotics; all infants harboured these antibiotic resistance genes at some point in the first year of life. Few ARGs persisted throughout the first year of life. Beta-lactam resistant Escherichia coli and Klebsiella pneumoniae were detected in 4 (5.3%) and 32 (42.7%) of subjects respectively. Conclusion: In this longitudinal cohort study of healthy infants living in a region with high endemic antibacterial resistance, we demonstrate that majority of the infants harboured a number of antibiotic resistance genes in their gut and showed that the infant gut resistome is diverse and dynamic over the first year of life.


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