RESUMO
The rise in antibiotic-resistant bacteria and contamination of water bodies is a serious issue that demands immense attention of scientific acumen. Here, we examined the pervasiveness of ESBL producing bacteria in Dal Lake and Wular Lake of Kashmir valley, India. Isolates were screened for antibiotic, heavy metal resistant elements, and their coexistence with mobile genetic elements. Out of two hundred one isolates screened, thirty-eight were found positive for ESBL production. Antibiotic profiling of ESBL positive isolates with 16 different drugs representing ß-lactam or -non-ß-lactam, exhibited multidrug resistance phenotype among 55% isolates. Molecular characterization revealed the occurrence of drug resistance determinants blaTEM, AmpC, qnrS, and heavy metal resistance genes (MRGs) merB, merP, merT, silE, silP, silS, and arsC. Furthermore, mobile genetic elements IntI, SulI, ISecp1, TN3, TN21 were also detected. Conjugation assay confirmed the transfer of different ARGs, HMRGs, and mobile elements in recipient Escherichia coli J53 AZR strain. Plasmid incompatibility studies showed blaTEM to be associated with Inc groups B/O, HI1, HI2, I1, N, FIA, and FIB. Co-occurrence of blaTEM, HMRGs, and mobile elements from the aquatic milieu of Kashmir, India has not been reported so far. From this study, the detection of the blaTEM gene in the bacteria Bacillus simplex and Brevibacterium frigoritolerans are found for the first time. Considering all the facts it becomes crucial to conduct studies in natural aquatic environments that could help depict the epidemiological situations in which the resistance mechanism might have clinical relevance.
RESUMO
Natural environment influenced by anthropogenic activities creates selective pressure for acquisition and spread of resistance genes. In this study, we determined the prevalence of Extended Spectrum ß-Lactamases producing gram negative bacteria from the River Yamuna, India, and report the identification and characterization of a novel CTX-M gene variant bla CTX-M-152 . Of the total 230 non-duplicate isolates obtained from collected water samples, 40 isolates were found positive for ESBL production through Inhibitor-Potentiation Disc Diffusion test. Based on their resistance profile, 3% were found exhibiting pandrug resistance (PDR), 47% extensively drug resistance (XDR), and remaining 50% showing multidrug resistant (MDR). Following screening and antimicrobial profiling, characterization of ESBLs (bla TEM and bla CTX-M ), and mercury tolerance determinants (merP, merT, and merB) were performed. In addition to abundance of bla TEM-116 (57.5%) and bla CTX-M-15 (37.5%), bacteria were also found to harbor other variants of ESBLs like bla CTX-M-71 (5%), bla CTX-M-3 (7.5%), bla CTX-M-32 (2.5%), bla CTX-M-152 (7.5%), bla CTX-M-55 (2.5%), along with some non-ESBLs; bla TEM-1 (25%) and bla OXY (5%). Additionally, co-occurrence of mercury tolerance genes were observed among 40% of isolates. In silico studies of the new variant, bla CTX-M-152 were conducted through modeling for the generation of structure followed by docking to determine its catalytic profile. CTX-M-152 was found to be an out-member of CTX-M-group-25 due to Q26H, T154A, G89D, P99S, and D146G substitutions. Five residues Ser70, Asn132, Ser237, Gly238, and Arg273 were found responsible for positioning of cefotaxime into the active site through seven H-bonds with binding energy of -7.6 Kcal/mol. Despite small active site, co-operative interactions of Ser237 and Arg276 were found actively contributing to its high catalytic efficiency. To the best of our knowledge, this is the first report of bla CTX-M-152 of CTX-M-group-25 from Indian subcontinent. Taking a note of bacteria harboring such high proportion of multidrug and mercury resistance determinants, their presence in natural water resources employed for human consumption increases the chances of potential risk to human health. Hence, deeper insights into mechanisms pertaining to resistance development are required to frame out strategies to tackle the situation and prevent acquisition and dissemination of resistance determinants so as to combat the escalating burden of infectious diseases.
RESUMO
BACKGROUND: Tomato leaf curl virus (ToLCV), a constituent of the genus Begomovirus, infects tomato and other plants with a hallmark disease symptom of upward leaf curling. Since microRNAs (miRs) are known to control plants developmental processes, we evaluated the roles of miRNAs in Tomato leaf curl New Delhi virus (ToLCNDV) induced leaf curling. RESULTS: Microarray analyses of miRNAs, isolated from the leaves of both healthy and ToLCNDV agroinfected tomato cv Pusa Ruby, revealed that ToLCNDV infection significantly deregulated various miRNAs representing ~13 different conserved families (e.g., miR319, miR172, etc.). The precursors of these miRNAs showed similar deregulated patterns, indicating that the transcription regulation of respective miRNA genes was perhaps the cause of deregulation. The expression levels of the miRNA-targeted genes were antagonistic with respect to the amount of corresponding miRNA. Such deregulation was tissue-specific in nature as no analogous misexpression was found in flowers. The accumulation of miR159/319 and miR172 was observed to increase with the days post inoculation (dpi) of ToLCNDV agroinfection in tomato cv Pusa Ruby. Similarly, these miRs were also induced in ToLCNDV agroinfected tomato cv JK Asha and chilli plants, both exhibiting leaf curl symptoms. Our results indicate that miR159/319 and miR172 might be associated with leaf curl symptoms. This report raises the possibility of using miRNA(s) as potential signature molecules for ToLCNDV infection. CONCLUSIONS: The expression of several host miRNAs is affected in response to viral infection. The levels of the corresponding pre-miRs and the predicted targets were also deregulated. This change in miRNA expression levels was specific to leaf tissues and observed to be associated with disease progression. Thus, certain host miRs are likely indicator of viral infection and could be potentially employed to develop viral resistance strategies.
