scholarly journals Development of CRSIPR-Cas13a-based antimicrobials capable of sequence-specific killing of target bacteria

2019 ◽  
Author(s):  
Kotaro Kiga ◽  
Xin-Ee Tan ◽  
Rodrigo Ibarra-Chávez ◽  
Shinya Watanabe ◽  
Yoshifumi Aiba ◽  
...  

AbstractEmergence of antimicrobial-resistant bacteria is an increasingly serious threat to global health, necessitating the development of innovative antimicrobials. We established a series of CRISPR-Cas13a-based antibacterial nucleocapsid, termed CapsidCas13a(s), capable of sequence-specific killing of carbapenem-resistant Escherichia coli and methicillin-resistant Staphylococcus aureus through promiscuous RNA cleavage after recognizing corresponding antimicrobial resistance genes. CapsidCas13a constructs were generated by packaging CRISPR-Cas13a into a bacteriophage capsid to target antimicrobial resistance genes. Contrary to Cas9-based antimicrobials that lack bacterial killing capacity when the target genes are located on a plasmid, the CapsidCas13a(s) exhibited strong bacterial killing activities upon recognizing target genes regardless of their location. The antimicrobials’ treatment efficacy was confirmed using a Galleria mellonella larvae model. Further, we demonstrated that the CapsidCas13a(s) can assist in bacterial gene detection without employing nucleic acid amplification and optical devices.

2020 ◽  
Vol 86 (20) ◽  
Author(s):  
Elizabeth A. Miller ◽  
Julia B. Ponder ◽  
Michelle Willette ◽  
Timothy J. Johnson ◽  
Kimberly L. VanderWaal

ABSTRACT Antimicrobial resistance (AMR) is a well-documented phenomenon in bacteria from many natural ecosystems, including wild animals. However, the specific determinants and spatial distribution of resistant bacteria and antimicrobial resistance genes (ARGs) in the environment remain incompletely understood. In particular, information regarding the importance of anthropogenic sources of AMR relative to that of other biological and ecological influences is lacking. We conducted a cross-sectional study of AMR in great horned owls (Bubo virginianus) and barred owls (Strix varia) admitted to a rehabilitation center in the midwestern United States. A combination of selective culture enrichment and shotgun metagenomic sequencing was used to identify ARGs from Enterobacteriaceae. Overall, the prevalence of AMR was comparable to that in past studies of resistant Enterobacteriaceae in raptors, with acquired ARGs being identified in 23% of samples. Multimodel regression analyses identified seasonality and owl age to be important predictors of the likelihood of the presence of ARGs, with birds sampled during warmer months being more likely to harbor ARGs than those sampled during cooler months and with birds in their hatch year being more likely to harbor β-lactam ARGs than adults. Beyond host-specific determinants, ARG-positive owls were also more likely to be recovered from areas of high agricultural land cover. Spatial clustering analyses identified a significant high-risk cluster of tetracycline resistance gene-positive owls in the southern sampling range, but this could not be explained by any predictor variables. Taken together, these results highlight the complex distribution of AMR in natural environments and suggest that both biological and anthropogenic factors play important roles in determining the emergence and persistence of AMR in wildlife. IMPORTANCE Antimicrobial resistance (AMR) is a multifaceted problem that poses a worldwide threat to human and animal health. Recent reports suggest that wildlife may play an important role in the emergence, dissemination, and persistence of AMR. As such, there have been calls for better integration of wildlife into current research on AMR, including the use of wild animals as biosentinels of AMR contamination in the environment. A One Health approach can be used to gain a better understanding of all AMR sources and pathways, particularly those at the human-animal-environment interface. Our study focuses on this interface in order to assess the effect of human-impacted landscapes on AMR in a wild animal. This work highlights the value of wildlife rehabilitation centers for environmental AMR surveillance and demonstrates how metagenomic sequencing within a spatial epidemiology framework can be used to address questions surrounding AMR complexity in natural ecosystems.


Author(s):  
Na Li ◽  
Chong Liu ◽  
Zhiguo Zhang ◽  
Hongna Li ◽  
Tingting Song ◽  
...  

The extensive use of antimicrobials in animal farms poses serious safety hazards to both the environment and public health, and this trend is likely to continue. Antimicrobial resistance genes (ARGs) are a class of emerging pollutants that are difficult to remove once introduced. Understanding the environmental transfer of antimicrobial-resistant bacteria (ARB) and ARGs is pivotal for creating control measures. In this review, we summarize the research progress on the spread and detection of ARB and ARG pollution related to animal husbandry. Molecular methods such as high-throughput sequencing have greatly enriched the information about ARB communities. However, it remains challenging to delineate mechanisms regarding ARG induction, transmission, and tempo-spatial changes in the whole process, from animal husbandry to multiple ecosystems. As a result, future research should be more focused on the mechanisms of ARG induction, transmission, and control. We also expect that future research will rely more heavily on metagenomic -analysis, metatranscriptomic sequencing, and multi-omics technologies


2017 ◽  
Vol 80 (12) ◽  
pp. 2048-2055 ◽  
Author(s):  
Tao Yu ◽  
Xiaobing Jiang ◽  
Yu Liang ◽  
Yanping Zhu ◽  
Jinhe Tian ◽  
...  

ABSTRACT The aim of this study was to investigate antimicrobial resistance and the presence and transferability of corresponding resistance genes and integrons in bacteria isolated from cooked meat samples in the People's Republic of China. A total of 150 isolates (22 species belonging to 15 genera) were isolated from 49 samples. Resistance of these isolates to antimicrobials was commonly observed; 42.7, 36.0, and 25.3% of the isolates were resistant to tetracycline, streptomycin, and ampicillin, respectively. Multidrug resistance was observed in 41 (27.3%) of the isolates. Sixteen resistance genes, i.e., blaTEM-1 and blaCTX-M-14 (β-lactams), aac(3)-IIa (gentamicin), strA and strB (streptomycin), qnrB and qnrS (fluoroquinolone), sul1, sul2, and sul3 (sulfamethoxazole), cat1 and cat2 (chloramphenicol), and tetM, tetA, tetS, and tetB (tetracycline), were found in 54 isolates. One isolate of Pseudomonas putida carried qnrB, and sequence analysis of the PCR product revealed 96% identity to qnrB2. The qnr genes were found coresiding and were cotransferred with bla genes in two isolates. Twelve isolates were positive for the class 1 integrase gene, and four isolates carried the class 2 integrase gene. However, no class 3 integrase gene was detected. One isolate of Proteus mirabilis carried dfrA32-ereA-aadA2, and this unusual array could be transferred to Escherichia coli. Nonclassic class 1 integrons lacking qacEΔ1 and sul1 genes were found in 2 of the 12 intI1-positive isolates. Our results revealed the presence of multidrug-resistant bacteria in cooked meats and the presence and transferability of resistance genes in some isolates, suggesting that cooked meat products may act as reservoirs of drug-resistant bacteria and may facilitate the spread of resistance genes.


Author(s):  
Hornel Koudokpon ◽  
Victorien Dougnon ◽  
Christelle Lougbegnon ◽  
Esther Deguenon ◽  
Wassiyath Mousse ◽  
...  

Background: The environment plays an important role in the dissemination of multidrug resistant bacteria, especially through the aquatic ecosystem, including hospital effluents, rivers, but also spring water and drinking water. This study aims to determine selected antimicrobial resistance genes in some aquatic matrices in southern Benin. Methods: Collected water samples were filtered through a membrane 0.22 µm thick. After filtration, the membrane was deposited on Muëller Hinton agar. Then the colonies resulting from this subculture were subjected to a microbiological examination by the conventional method. The antibiotic sensitivity test was carried out by the Kirby Bauer method according to the recommendations of the French Society of Microbiology. Resistance genes were looked for by PCR. Results: Of the 222 water samples collected, 265 bacterial strains were isolated, the majority of which were strains of Coagulase Negative Staphylococcus (CNS) with 37.74% (n = 100), followed by strains of Klebsiella pneumoniae (21.89%; n = 58), Escherichia coli (10.57%; n = 28). All isolated gram-negative bacilli strains are multidrug resistant with resistance of all strains to amoxicillin, ampicillin and amoxicillin + clavulanic acid. Of the 15 resistance genes searched in the genome of Gram-negative bacilli strains, 8 were detected, namely the TEM, SHV, CTX-M15, VIM, NDM, SUL1, SUL2 and AADA genes. Resistance of CNS strains to amoxicillin, oxacillin and cefoxitin was observed. The meca gene was detected in all CNS strains. The vanA and VanB genes were only detected in strains isolated from drinking water in sachets collected from producers and street sellers. Conclusion: These results show the dissemination of resistance genes in Benin and once again confirms the urgency of a global fight against antimicrobial resistance.


2019 ◽  
Vol 64 (2) ◽  
pp. 125-137 ◽  
Author(s):  
Liese Van Gompel ◽  
Wietske Dohmen ◽  
Roosmarijn E C Luiken ◽  
Martijn Bouwknegt ◽  
Lourens Heres ◽  
...  

Abstract Objectives Slaughterhouse staff is occupationally exposed to antimicrobial resistant bacteria. Studies reported high antimicrobial resistance gene (ARG) abundances in slaughter pigs. This cross-sectional study investigated occupational exposure to tetracycline (tetW) and macrolide (ermB) resistance genes and assessed determinants for faecal tetW and ermB carriage among pig slaughterhouse workers. Methods During 2015–2016, 483 faecal samples and personal questionnaires were collected from workers in a Dutch pig abattoir, together with 60 pig faecal samples. Human dermal and respiratory exposure was assessed by examining 198 carcass, 326 gloves, and 33 air samples along the line, next to 198 packed pork chops to indicate potential consumer exposure. Samples were analyzed by qPCR (tetW, ermB). A job exposure matrix was created by calculating the percentage of tetW and ermB positive carcasses or gloves for each job position. Multiple linear regression models were used to link exposure to tetW and ermB carriage. Results Workers are exposed to tetracycline and macrolide resistance genes along the slaughter line. Tetw and ermB gradients were found for carcasses, gloves, and air filters. One packed pork chop contained tetW, ermB was non-detectable. Human faecal tetW and ermB concentrations were lower than in pig faeces. Associations were found between occupational tetW exposure and human faecal tetW carriage, yet, not after model adjustments. Sampling round, nationality, and smoking were determinants for ARG carriage. Conclusion We demonstrated clear environmental tetracycline and macrolide resistance gene exposure gradients along the slaughter line. No robust link was found between ARG exposure and human faecal ARG carriage.


2015 ◽  
Vol 81 (14) ◽  
pp. 4600-4606 ◽  
Author(s):  
Amira Shousha ◽  
Nattakarn Awaiwanont ◽  
Dmitrij Sofka ◽  
Frans J. M. Smulders ◽  
Peter Paulsen ◽  
...  

ABSTRACTAntimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments. The transfer of antimicrobial resistance genes by phages could underlie the origin of resistant bacteria found in food. We show that chicken meat carries a number of phages capable of transferring antimicrobial resistance. Of 243 phages randomly isolated from chicken meat, about a quarter (24.7%) were able to transduce resistance to one or more of the five antimicrobials tested intoEscherichia coliATCC 13706 (DSM 12242). Resistance to kanamycin was transduced the most often, followed by that to chloramphenicol, with four phages transducing tetracycline resistance and three transducing ampicillin resistance. Phages able to transduce antimicrobial resistance were isolated from 44% of the samples of chicken meat that we tested. The statistically significant (P= 0.01) relationship between the presence of phages transducing kanamycin resistance andE. coliisolates resistant to this antibiotic suggests that transduction may be an important mechanism for transferring kanamycin resistance toE. coli. It appears that the transduction of resistance to certain antimicrobials, e.g., kanamycin, not only is widely distributed inE. coliisolates found on meat but also could represent a major mechanism for resistance transfer. The result is of high importance for animal and human health.


2019 ◽  
Author(s):  
Maria Fernanda Loayza Villa ◽  
Alejandro Torres ◽  
Lixin Zhang ◽  
Gabriel Trueba

Abstract Background: The use of antimicrobials in the animal industry has increased the prevalence of antibiotic resistant bacteria and antimicrobial-resistance genes which can be transferred to human microbiota through the food chain or the environment. To reduce the influx of antibiotic-resistance to the human microbiota, restrictions on antimicrobials (in food animals) have been implemented in different countries. We investigated the impact of an antimicrobial restriction on the frequency of antimicrobial-resistant bacteria in pigs (PCI 1050) from an Ecuadorian farm. Results: No differences in antimicrobial resistant coliforms or antimicrobial resistance genes (richness and abundance) were found when we compared animals fed with or without antibiotics. Nevertheless, the absence of antimicrobials in pigs didn’t impact the productive performance of animals. Conclusion: Fitness costs of antimicrobial resistance in bacteria within intestinal microbiota of animals seems to be overestimated. Avoiding antimicrobials as prophylactics in pigs fed is not enough to control maintenance and spread of antimicrobial resistance.


2009 ◽  
Vol 72 (5) ◽  
pp. 1089-1093 ◽  
Author(s):  
MUEEN ASLAM ◽  
MOUSSA S. DIARRA ◽  
CARA SERVICE ◽  
HEIDI REMPEL

The goal of this study was to assess the distribution of antimicrobial resistance (AMR) genes in Escherichia coli isolates recovered from a commercial beef processing plant. A total of 123 antimicrobial-resistant E. coli isolates were used: 34 from animal hides, 10 from washed carcasses, 27 from conveyers for moving carcasses and meat, 26 from beef trimmings, and 26 from ground meat. The AMR genes for β-lactamase (blaCMY, blaSHV, and blaTEM), tetracycline (tet(A), tet(B), and tet(C)), sulfonamides (sul1, sul2, and sul3), and aminoglycoside (strA and strB) were detected by PCR assay. The distribution of tet(B), tet(C), sul1, blaTEM, strA, and strB genes was significantly different among sample sources. E. coli isolates positive for the tet(B) gene and for both strA and strB genes together were significantly associated with hide, washed carcass, and ground meat samples, whereas sul1 gene was associated with washed carcass and beef trimming samples. The blaTEM gene was significantly associated with ground meat samples. About 50% of tetracycline-resistant E. coli isolates were positive for tet(A) (14%), tet(B) (15%), or tet(C) (21%) genes or both tet(B) and tet(C) genes together (3%). The sul2 gene or both sul1 and sul2 genes were found in 23% of sulfisoxazole-resistant E. coli isolates, whereas the sul3 gene was not found in any of the E. coli isolates tested. The majority of streptomycin-resistant E. coli isolates (76%) were positive for the strA and strB genes together. The blaCMY, blaTEM, and blaSHV genes were found in 12, 56, and 4%, respectively, of ampicillin-resistant E. coli isolates. These data suggest that E. coli isolates harboring AMR genes are widely distributed in meat processing environments and can create a pool of transferable resistance genes for pathogens. The results of this study underscore the need for effective hygienic and sanitation procedures in meat plants to reduce the risks of contamination with antimicrobial-resistant bacteria.


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