scholarly journals Inhibitory Impact of Bifidobacteria on the Transfer of β-Lactam Resistance among Enterobacteriaceae in the Gnotobiotic Mouse Digestive Tract

2006 ◽  
Vol 73 (3) ◽  
pp. 855-860 ◽  
Author(s):  
C. Moubareck ◽  
M. Lecso ◽  
E. Pinloche ◽  
M. J. Butel ◽  
F. Doucet-Populaire

ABSTRACT While looking for new means to limit the dissemination of antibiotic resistance, we evaluated the role of potentially probiotic bifidobacteria on the transfer of resistance genes between enterobacteria. Transfers of bla genes encoding extended-spectrum β-lactamases (SHV-5 and CTX-M-15) were studied in the absence or presence of bifidobacteria. In vitro, transfer frequencies of these bla genes decreased significantly in the presence of three of five tested strains, i.e., Bifidobacterium longum CUETM-89-215, Bifidobacterium bifidum CIP-56.7T, and Bifidobacterium pseudocatenulatum CIP-104168T. Four transfer experiments were conducted in the digestive tract of gnotobiotic mice, the first three observing the effect of B. longum CUETM-89-215, B. bifidum CIP-56.7T, and B. pseudocatenulatum CIP-104168T on bla SHV-5 transfer and the fourth experiment studying the effect of B. bifidum CIP-56.7T on bla CTX-M-15 transfer. These experiments revealed significant decreases in the transconjugant levels (up to 3 logs) in mice having received B. bifidum CIP-56.7T or B. pseudocatenulatum CIP-104168T compared to control mice. Bifidobacteria appear to have an inhibitory impact on the transfer of antibiotic resistance genes. The inhibitory effect is associated to specific bifidobacterial strains and may be related to the production of thermostable metabolites by these strains.

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yasmin Neves Vieira Sabino ◽  
Mateus Ferreira Santana ◽  
Linda Boniface Oyama ◽  
Fernanda Godoy Santos ◽  
Ana Júlia Silva Moreira ◽  
...  

AbstractInfections caused by multidrug resistant bacteria represent a therapeutic challenge both in clinical settings and in livestock production, but the prevalence of antibiotic resistance genes among the species of bacteria that colonize the gastrointestinal tract of ruminants is not well characterized. Here, we investigate the resistome of 435 ruminal microbial genomes in silico and confirm representative phenotypes in vitro. We find a high abundance of genes encoding tetracycline resistance and evidence that the tet(W) gene is under positive selective pressure. Our findings reveal that tet(W) is located in a novel integrative and conjugative element in several ruminal bacterial genomes. Analyses of rumen microbial metatranscriptomes confirm the expression of the most abundant antibiotic resistance genes. Our data provide insight into antibiotic resistange gene profiles of the main species of ruminal bacteria and reveal the potential role of mobile genetic elements in shaping the resistome of the rumen microbiome, with implications for human and animal health.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
David L Paterson ◽  
Burcu Isler ◽  
Patrick N A Harris

Abstract Ceftriaxone resistance in the Enterobacterales is typically the result of production of ESBLs or AmpC β-lactamases. The genes encoding these enzymes are often co-located with other antibiotic resistance genes leading to resistance to aminoglycosides, quinolones and trimethoprim/sulfamethoxazole. Carbapenems are stable to ESBLs and AmpC giving them reliable in vitro activity against producers of these β-lactamases. In contrast, piperacillin/tazobactam and amoxicillin/clavulanate are compromised by co-production of OXA-1, which is not inhibited by tazobactam or clavulanate. These in vitro findings provide an explanation for the MERINO trial outcomes, where 3.7% (7/191) randomized to meropenem died compared with 12.3% (23/187) randomized to piperacillin/tazobactam as definitive treatment of bloodstream infection due to ceftriaxone-resistant organisms. No randomized trials have yet put cefepime and carbapenems head to head, but some observational studies have shown worse outcomes with cefepime. We argue that carbapenems are the antibiotics of choice for ceftriaxone-resistant Enterobacterales.


2013 ◽  
Vol 80 (4) ◽  
pp. 1482-1488 ◽  
Author(s):  
Jing Yang ◽  
Chao Wang ◽  
Jinyu Wu ◽  
Li Liu ◽  
Gang Zhang ◽  
...  

ABSTRACTThe genusExiguobacteriumcan adapt readily to, and survive in, diverse environments. Our study demonstrated thatExiguobacteriumsp. strain S3-2, isolated from marine sediment, is resistant to five antibiotics. The plasmid pMC1 in this strain carries seven putative resistance genes. We functionally characterized these resistance genes inEscherichia coli, and genes encoding dihydrofolate reductase and macrolide phosphotransferase were considered novel resistance genes based on their low similarities to known resistance genes. The plasmid G+C content distribution was highly heterogeneous. Only the G+C content of one block, which shared significant similarity with a plasmid fromExiguobacterium arabatum, fit well with the mean G+C content of the host. The remainder of the plasmid was composed of mobile elements with a markedly lower G+C ratio than the host. Interestingly, five mobile elements located on pMC1 showed significant similarities to sequences found in pathogens. Our data provided an example of the link between resistance genes in strains from the environment and the clinic and revealed the aggregation of antibiotic resistance genes in bacteria isolated from fish farms.


2008 ◽  
Vol 74 (19) ◽  
pp. 6032-6040 ◽  
Author(s):  
Anna Rosander ◽  
Eamonn Connolly ◽  
Stefan Roos

ABSTRACT The spread of antibiotic resistance in pathogens is primarily a consequence of the indiscriminate use of antibiotics, but there is concern that food-borne lactic acid bacteria may act as reservoirs of antibiotic resistance genes when distributed in large doses to the gastrointestinal tract. Lactobacillus reuteri ATCC 55730 is a commercially available probiotic strain which has been found to harbor potentially transferable resistance genes. The aims of this study were to define the location and nature of β-lactam, tetracycline, and lincosamide resistance determinants and, if they were found to be acquired, attempt to remove them from the strain by methods that do not genetically modify the organism before subsequently testing whether the probiotic characteristics were retained. No known β-lactam resistance genes was found, but penicillin-binding proteins from ATCC 55730, two additional resistant strains, and three sensitive strains of L. reuteri were sequenced and comparatively analyzed. The β-lactam resistance in ATCC 55730 is probably caused by a number of alterations in the corresponding genes and can be regarded as not transferable. The strain was found to harbor two plasmids carrying tet(W) tetracycline and lnu(A) lincosamide resistance genes, respectively. A new daughter strain, L. reuteri DSM 17938, was derived from ATCC 55730 by removal of the two plasmids, and it was shown to have lost the resistances associated with them. Direct comparison of the parent and daughter strains for a series of in vitro properties and in a human clinical trial confirmed the retained probiotic properties of the daughter strain.


2020 ◽  
Vol 18 (4) ◽  
pp. 477-493
Author(s):  
Johannes Cornelius Jacobus Fourie ◽  
Cornelius Carlos Bezuidenhout ◽  
Tomasz Janusz Sanko ◽  
Charlotte Mienie ◽  
Rasheed Adeleke

Abstract Until recently, research has focused on Clostridium perfringens in clinical settings without considering environmental isolates. In this study, environmental genomes were used to investigate possible antibiotic resistance and the presence of virulence traits in C. perfringens strains from raw surface water. In silico assembly of three C. perfringens strains, DNA generated almost complete genomes setting their length ranging from 3.4 to 3.6 Mbp with GC content of 28.18%. An average of 3,175 open reading frames was identified, with the majority associated with carbohydrate and protein metabolisms. The genomes harboured several antibiotic resistance genes for glycopeptides, macrolide–lincosamide–streptogramin B, β-lactam, trimethoprim, tetracycline and aminoglycosides and also the presence of several genes encoding for polypeptides and multidrug resistance efflux pumps and 35 virulence genes. Some of these encode for haemolysins, sialidase, hyaluronidase, collagenase, perfringolysin O and phospholipase C. All three genomes contained sequences indicating phage, antibiotic resistance and pathogenic islands integration sites. A genomic comparison of these three strains confirmed high similarity and shared core genes with clinical C. perfringens strains, highlighting their health security risks. This study provides a genomic insight into the potential pathogenicity of C. perfringens present in the environment and emphasises the importance of monitoring this niche in the future.


2009 ◽  
Vol 75 (19) ◽  
pp. 6352-6360 ◽  
Author(s):  
Joanna Boguslawska ◽  
Joanna Zycka-Krzesinska ◽  
Andrea Wilcks ◽  
Jacek Bardowski

ABSTRACT Tetracycline-resistant Lactococcus lactis strains originally isolated from Polish raw milk were analyzed for the ability to transfer their antibiotic resistance genes in vitro, using filter mating experiments, and in vivo, using germfree rats. Four of six analyzed L. lactis isolates were able to transfer tetracycline resistance determinants in vitro to L. lactis Bu2-60, at frequencies ranging from 10−5 to 10−7 transconjugants per recipient. Three of these four strains could also transfer resistance in vitro to Enterococcus faecalis JH2-2, whereas no transfer to Bacillus subtilis YBE01, Pseudomonas putida KT2442, Agrobacterium tumefaciens UBAPF2, or Escherichia coli JE2571 was observed. Rats were initially inoculated with the recipient E. faecalis strain JH2-2, and after a week, the L. lactis IBB477 and IBB487 donor strains were introduced. The first transconjugants were detected in fecal samples 3 days after introduction of the donors. A subtherapeutic concentration of tetracycline did not have any significant effect on the number of transconjugants, but transconjugants were observed earlier in animals dosed with this antibiotic. Molecular analysis of in vivo transconjugants containing the tet(M) gene showed that this gene was identical to tet(M) localized on the conjugative transposon Tn916. Primer-specific PCR confirmed that the Tn916 transposon was complete in all analyzed transconjugants and donors. This is the first study showing in vivo transfer of a Tn916-like antibiotic resistance transposon from L. lactis to E. faecalis. These data suggest that in certain cases food lactococci might be involved in the spread of antibiotic resistance genes to other lactic acid bacteria.


2019 ◽  
Author(s):  
Marinelle Rodrigues ◽  
Sara W. McBride ◽  
Karthik Hullahalli ◽  
Kelli L. Palmer ◽  
Breck A. Duerkop

AbstractThe innovation of new therapies to combat multidrug-resistant (MDR) bacteria is being outpaced by the continued rise of MDR bacterial infections. Of particular concern are hospital-acquired infections (HAIs) recalcitrant to antibiotic therapies. The Gram-positive intestinal pathobiontEnterococcus faecalisis associated with HAIs and some strains are MDR. Therefore, novel strategies to controlE. faecalispopulations are needed. We previously characterized anE. faecalisType II CRISPR-Cas system and demonstrated its utility in the sequence-specific removal of antibiotic resistance determinants. Here we present work describing the adaption of this CRISPR-Cas system into a constitutively expressed module encoded on a pheromone-responsive conjugative plasmid that efficiently transfers toE. faecalisfor the selective removal of antibiotic resistance genes. Usingin vitrocompetition assays, we show that these CRISPR-Cas-encoding delivery plasmids, or CRISPR-Cas antimicrobials, can reduce the occurrence of antibiotic resistance in enterococcal populations in a sequence-specific manner. Furthermore, we demonstrate that deployment of CRISPR-Cas antimicrobials in the murine intestine reduces the occurrence of antibiotic-resistantE. faecalisby several orders of magnitude. Finally, we show thatE. faecalisdonor strains harboring CRISPR-Cas antimicrobials are immune to uptake of antibiotic resistance determinantsin vivo. Our results demonstrate that conjugative delivery of CRISPR-Cas antimicrobials may be adaptable for future deployment from probiotic bacteria for exact targeting of defined MDR bacteria or for precision engineering of polymicrobial communities in the mammalian intestine.ImportanceCRISPR-Cas nucleic acid targeting systems hold promise for the amelioration of multidrug-resistant enterococci, yet the utility of such tools in the context of the intestinal environment where enterococci reside is understudied. We describe the development of a CRISPR-Cas antimicrobial, deployed on a conjugative plasmid, for the targeted removal of antibiotic resistance genes from intestinalEnterococcus faecalis. We demonstrate that CRISPR-Cas targeting reduces antibiotic resistance ofE. faecalisby several orders of magnitude in the intestine. Although barriers exist that influence the penetrance of the conjugative CRISPR-Cas antimicrobial among target recipientE. faecaliscells, the removal of antibiotic resistance genes inE. faecalisupon uptake of the CRISPR-Cas antimicrobial is absolute. In addition, cells that obtain the CRISPR-Cas antimicrobial are immunized against the acquisition of new antibiotic resistance genes. This study suggests a potential path toward plasmid based CRISPR-Cas therapies in the intestine.


2018 ◽  
Author(s):  
Valerie J. Price ◽  
Sara W. McBride ◽  
Karthik Hullahalli ◽  
Anushila Chatterjee ◽  
Breck A. Duerkop ◽  
...  

AbstractCRISPR-Cas systems are barriers to horizontal gene transfer (HGT) in bacteria. Little is known about CRISPR-Cas interactions with conjugative plasmids, and studies investigating CRISPR-Cas/plasmid interactions inin vivomodels relevant to infectious disease are lacking. These are significant gaps in knowledge because conjugative plasmids disseminate antibiotic resistance genes among pathogensin vivo, and it is essential to identify strategies to reduce the spread of these elements. We use enterococci as models to understand the interactions of CRISPR-Cas with conjugative plasmids.Enterococcus faecalisis a native colonizer of the mammalian intestine and harbors pheromone-responsive plasmids (PRPs). PRPs mediate inter- and intraspecies transfer of antibiotic resistance genes. We assessedE. faecalisCRISPR-Cas anti-PRP activity in the mouse intestine and under varyingin vitroconditions. We observed striking differences in CRISPR-Cas efficiencyin vitroversusin vivo. With few exceptions, CRISPR-Cas blocked intestinal PRP dissemination, whilein vitro, the PRP frequently escaped CRISPR-Cas defense. Our results further the understanding of CRISPR-Cas biology by demonstrating that standardin vitroexperiments do not adequately model thein vivoanti-plasmid activity of CRISPR-Cas. Additionally, our work identifies several variables that impact the apparentin vitroanti-plasmid activity of CRISPR-Cas, including planktonic versus biofilm settings, different donor/recipient ratios, production of a plasmid-encoded bacteriocin, and the time point at which matings are sampled. Our results are clinically significant because they demonstrate that barriers to HGT encoded by normal human microbiota can have significant impacts onin vivoantibiotic resistance dissemination.ImportanceCRISPR-Cas is a type of immune system encoded by bacteria that is hypothesized to be a natural impediment to the spread of antibiotic resistance genes. In this study, we directly assessed the impact of CRISPR-Cas on antibiotic resistance dissemination in the mammalian intestine and under varyingin vitroconditions. We observed a robust effect of CRISPR-Cas onin vivobut notin vitrodissemination of antibiotic resistance plasmids in the native mammalian intestinal colonizerEnterococcus faecalis. We conclude that standard laboratory experiments currently do not appropriately model thein vivoconditions where antibiotic resistance dissemination occurs betweenE. faecalisstrains. Moreover, our results demonstrate that CRISPR-Cas encoded by native members of the mammalian intestinal microbiota can block the spread of antibiotic resistance plasmids.


2020 ◽  
Vol 295 (32) ◽  
pp. 10870-10884 ◽  
Author(s):  
J. Andrew N. Alexander ◽  
Mariia Radaeva ◽  
Dustin T. King ◽  
Henry F. Chambers ◽  
Artem Cherkasov ◽  
...  

Methicillin-resistant Staphylococcus aureus (MRSA) infections cause significant mortality and morbidity globally. MRSA resistance to β-lactam antibiotics is mediated by two divergons that control levels of a β-lactamase, PC1, and a penicillin-binding protein poorly acylated by β-lactam antibiotics, PBP2a. Expression of genes encoding these proteins is controlled by two integral membrane proteins, BlaR1 and MecR1, which both have an extracellular β-lactam–binding sensor domain. Here, we solved the X-ray crystallographic structures of the BlaR1 and MecR1 sensor domains in complex with avibactam, a diazabicyclooctane β-lactamase inhibitor at 1.6–2.0 Å resolution. Additionally, we show that S. aureus SF8300, a clinically relevant strain from the USA300 clone of MRSA, responds to avibactam by up-regulating the expression of the blaZ and pbp2a antibiotic-resistance genes, encoding PC1 and PBP2a, respectively. The BlaR1–avibactam structure of the carbamoyl-enzyme intermediate revealed that avibactam is bound to the active-site serine in two orientations ∼180° to each other. Although a physiological role of the observed alternative pose remains to be validated, our structural results hint at the presence of a secondary sulfate-binding pocket that could be exploited in the design of future inhibitors of BlaR1/MecR1 sensor domains or the structurally similar class D β-lactamases. The MecR1–avibactam structure adopted a singular avibactam orientation similar to one of the two states observed in the BlaR1–avibactam structure. Given avibactam up-regulates expression of blaZ and pbp2a antibiotic resistance genes, we suggest further consideration and research is needed to explore what effects administering β-lactam–avibactam combinations have on treating MRSA infections.


2021 ◽  
Vol 31 (4) ◽  
pp. 51-60
Author(s):  
Vu Nhi Ha ◽  
Kieu Chi Thanh ◽  
Nguyen Thai Son ◽  
Dao Van Thang ◽  
Tran Huy Hoang

Acinetobacter baumannii (A. baumannii) is currently ranked as the frst concern for the development of new antibiotics due to its capacity of resistance to all available families of antibiotics. The most common mechanism of antibiotic resistance development in A. baumannii is through the acquisition of mobile genetic elements such as plasmid, transposon and integrons carrying resistance genes. A. baumannii strain TN81 was isolated from sputum specimen of a 45-year-old man at Thanh Nhan Hospital (Hanoi, Vietnam) and confrmed to be a multidrug resistance strain with high minimum inhibitory concentration value of 8/9 type of antibiotics, especially colistin. De novo assembly of the whole genome shotgun sequence of strain TN81 yielded an estimated genome size of 3,739,193 bp with 593 contigs and N50 is 9,126 bp. MLST analysis showed that TN81 belongs to ST164, which was frst reported as genome assembly in Vietnam. Resistance genes identifcation through database found that TN81 contained 12 genes encoding for antibiotic resistance. Notably, we performed de novo assembly of plasmid through short read sequence and identifed two potential plasmid-encoded antibiotic resistance genes (ant(2’’)-Ia / aadB and tet (39), which were reported for the first time as in ST164 group. This study aimed to investigate the plasmid-containing antibiotic resistance genes from a nosocomial isolate of Acinetobacter baumannii. Conclusively, all of these results would be crucial information on antibiotic resistance in A. baumannii in Vietnam.


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