RESUMO
Bacterial species are hosts to horizontally acquired mobile genetic elements (MGEs), which encode virulence, toxin, antimicrobial resistance, and other metabolic functions. The bipartite genome of Vibrio cholerae harbors sporadic and conserved MGEs that contribute in the disease development and survival of the pathogens. For a comprehensive understanding of dynamics of MGEs in the bacterial genome, we engineered the genome of V. cholerae and examined in vitro and in vivo stability of genomic islands (GIs), integrative conjugative elements (ICEs), and prophages. Recombinant vectors carrying the integration module of these GIs, ICE and CTXΦ, helped us to understand the efficiency of integrations of MGEs in the V. cholerae chromosome. We have deleted more than 250 acquired genes from 6 different loci in the V. cholerae chromosome and showed contribution of CTX prophage in the essentiality of SOS response master regulator LexA, which is otherwise not essential for viability in other bacteria, including Escherichia coli In addition, we observed that the core genome-encoded RecA helps CTXΦ to bypass V. cholerae immunity and allow it to replicate in the host bacterium in the presence of similar prophage in the chromosome. Finally, our proteomics analysis reveals the importance of MGEs in modulating the levels of cellular proteome. This study engineered the genome of V. cholerae to remove all of the GIs, ICEs, and prophages and revealed important interactions between core and acquired genomes.
Assuntos
Genoma Bacteriano/genética , Ilhas Genômicas/genética , Vibrio cholerae/genética , Proteínas de Bactérias/genética , Conjugação Genética/genética , Engenharia Genética , Sequências Repetitivas Dispersas/genética , Prófagos/genética , Serina Endopeptidases/genética , Vibrio cholerae/patogenicidadeRESUMO
The Bay of Bengal is known as the epicenter for seeding several devastating cholera outbreaks across the globe. Vibrio cholerae, the etiological agent of cholera, has extraordinary competency to acquire exogenous DNA by horizontal gene transfer (HGT) and adapt them into its genome for structuring metabolic processes, developing drug resistance, and colonizing the human intestine. Antimicrobial resistance (AMR) in V. cholerae has become a global concern. However, little is known about the identity of the resistance traits, source of AMR genes, acquisition process, and stability of the genetic elements linked with resistance genes in V. cholerae Here we present details of AMR profiles of 443 V. cholerae strains isolated from the stool samples of diarrheal patients from two regions of India. We sequenced the whole genome of multidrug-resistant (MDR) and extensively drug-resistant (XDR) V. cholerae to identify AMR genes and genomic elements that harbor the resistance traits. Our genomic findings were further confirmed by proteome analysis. We also engineered the genome of V. cholerae to monitor the importance of the autonomously replicating plasmid and core genome in the resistance profile. Our findings provided insights into the genomes of recent cholera isolates and identified several acquired traits including plasmids, transposons, integrative conjugative elements (ICEs), pathogenicity islands (PIs), prophages, and gene cassettes that confer fitness to the pathogen. The knowledge generated from this study would help in better understanding of V. cholerae evolution and management of cholera disease by providing clinical guidance on preferred treatment regimens.
Assuntos
Cólera/microbiologia , Farmacorresistência Bacteriana Múltipla/genética , Transferência Genética Horizontal , Genoma Bacteriano/genética , Vibrio cholerae/genética , Antibacterianos/farmacologia , Conjugação Genética/genética , Elementos de DNA Transponíveis/genética , Diarreia/microbiologia , Evolução Molecular , Fezes/microbiologia , Variação Genética , Ilhas Genômicas/genética , Humanos , Imipenem/farmacologia , Índia , Sequências Repetitivas Dispersas/genética , Fenótipo , Plasmídeos/genética , Prófagos/genética , Proteoma , Vibrio cholerae/efeitos dos fármacos , Vibrio cholerae/isolamento & purificação , Vibrio cholerae/patogenicidade , Vibrio cholerae O1/genética , Vibrio cholerae O1/isolamento & purificação , Vibrio cholerae O1/patogenicidade , Sequenciamento Completo do GenomaRESUMO
Antimicrobial resistance (AMR) among bacterial species that resides in complex ecosystems is a natural phenomenon. Indiscriminate use of antimicrobials in healthcare, livestock, and agriculture provides an evolutionary advantage to the resistant variants to dominate the ecosystem. Ascendency of resistant variants threatens the efficacy of most, if not all, of the antimicrobial drugs commonly used to prevent and/or cure microbial infections. Resistant phenotype is very common in enteric bacteria. The most common mechanisms of AMR are enzymatic modifications to the antimicrobials or their target molecules. In enteric bacteria, most of the resistance traits are acquired by horizontal gene transfer from closely or distantly related bacterial population. AMR traits are generally linked with mobile genetic elements (MGEs) and could rapidly disseminate to the bacterial species through horizontal gene transfer (HGT) from a pool of resistance genes. Although prevalence of AMR genes among pathogenic bacteria is widely studied in the interest of infectious disease management, the resistance profile and the genetic traits that encode resistance to the commensal microbiota residing in the gut of healthy humans are not well-studied. In the present study, we have characterized AMR phenotypes and genotypes of five dominant commensal enteric bacteria isolated from the gut of healthy Indians. Our study revealed that like pathogenic bacteria, enteric commensals are also multidrug-resistant. The genes encoding antibiotic resistance are physically linked with MGEs and could disseminate vertically to the progeny and laterally to the distantly related microbial species. Consequently, the AMR genes present in the chromosome of commensal gut bacteria could be a potential source of resistance functions for other enteric pathogens.
Assuntos
Farmacorresistência Bacteriana/genética , Microbioma Gastrointestinal/genética , Genes Bacterianos/genética , Fenótipo , Simbiose , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Elementos de DNA Transponíveis/genética , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Transferência Genética Horizontal/genética , Genoma Bacteriano , Genótipo , Humanos , Sequências Repetitivas Dispersas/genética , Metagenoma/genética , Testes de Sensibilidade Microbiana , Transformação Genética/genética , Vibrio cholerae/genética , Sequenciamento Completo do GenomaRESUMO
The cheaper surgical dressings often leave residual adhesive, which can be unsightly and uncomfortable. We describe a simple and cost-effective procedure for removing adhesive residue using micropore tape. This technique can be easily performed by anyone, including the patients themselves.
Assuntos
Adesivos , Bandagens , HumanosRESUMO
Emergence of antimicrobial resistant Gram-negative bacteria has created a serious global health crisis and threatens the effectiveness of most, if not all, antibiotics commonly used to prevent and treat bacterial infections. There is a dearth of detailed studies on the prevalence of antimicrobial resistance (AMR) patterns in India. Here, we have isolated and examined AMR patterns of 654 enteric pathogens and investigated complete genome sequences of isolates from six representative genera, which in aggregate encode resistance against 22 antibiotics representing nine distinct drug classes. This study revealed that ~97% isolates are resistant against ≥2 antibiotics, ~24% isolates are resistant against ≥10 antibiotics and ~3% isolates are resistant against ≥15 antibiotics. Analyses of whole genome sequences of six extensive drug resistant enteric pathogens revealed presence of multiple mobile genetic elements, which are physically linked with resistance traits. These elements are therefore appearing to be responsible for disseminating drug resistance among bacteria through horizontal gene transfer. The present study provides insights into the linkages between the resistance patterns to certain antibiotics and their usage in India. The findings would be useful to understand the genetics of resistance traits and severity of and difficulty in tackling AMR enteric pathogens.
Assuntos
Farmacorresistência Bacteriana/efeitos dos fármacos , Resistência a Múltiplos Medicamentos/genética , Microbioma Gastrointestinal/genética , Antibacterianos/farmacologia , Bactérias/genética , Infecções Bacterianas/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla/genética , Microbioma Gastrointestinal/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Humanos , Índia , Testes de Sensibilidade Microbiana , Fenótipo , Sequenciamento Completo do GenomaRESUMO
To explore the natural microbial community of any ecosystems by high-resolution molecular approaches including next generation sequencing, it is extremely important to develop a sensitive and reproducible DNA extraction method that facilitate isolation of microbial DNA of sufficient purity and quantity from culturable and uncultured microbial species living in that environment. Proper lysis of heterogeneous community microbial cells without damaging their genomes is a major challenge. In this study, we have developed an improved method for extraction of community DNA from different environmental and human origin samples. We introduced a combination of physical, chemical and mechanical lysis methods for proper lysis of microbial inhabitants. The community microbial DNA was precipitated by using salt and organic solvent. Both the quality and quantity of isolated DNA was compared with the existing methodologies and the supremacy of our method was confirmed. Maximum recovery of genomic DNA in the absence of substantial amount of impurities made the method convenient for nucleic acid extraction. The nucleic acids obtained using this method are suitable for different downstream applications. This improved method has been named as the THSTI method to depict the Institute where the method was developed.