# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 502 | 0 | 0.7754 | A highly specialized flavin mononucleotide riboswitch responds differently to similar ligands and confers roseoflavin resistance to Streptomyces davawensis. Streptomyces davawensis is the only organism known to synthesize the antibiotic roseoflavin, a riboflavin (vitamin B2) analog. Roseoflavin is converted to roseoflavin mononucleotide (RoFMN) and roseoflavin adenine dinucleotide in the cytoplasm of target cells. (Ribo-)Flavin mononucleotide (FMN) riboswitches are genetic elements, which in many bacteria control genes responsible for the biosynthesis and transport of riboflavin. Streptomyces davawensis is roseoflavin resistant, and the closely related bacterium Streptomyces coelicolor is roseoflavin sensitive. The two bacteria served as models to investigate roseoflavin resistance of S. davawensis and to analyze the mode of action of roseoflavin in S. coelicolor. Our experiments demonstrate that the ribB FMN riboswitch of S. davawensis (in contrast to the corresponding riboswitch of S. coelicolor) is able to discriminate between the two very similar flavins FMN and RoFMN and shows opposite responses to the latter ligands. | 2012 | 22740651 |
| 507 | 1 | 0.7745 | Tellurite resistance and reduction by obligately aerobic photosynthetic bacteria. Seven species of obligately aerobic photosynthetic bacteria of the genera Erythromicrobium, Erythrobacter, and Roseococcus demonstrated high-level resistance to tellurite and accumulation of metallic tellurium crystals. High-level resistance without tellurite reduction was observed for Roseococcus thiosulfatophilus and Erythromicrobium ezovicum grown with certain organic carbon sources, implying that tellurite reduction is not essential to confer tellurite resistance. | 1996 | 16535446 |
| 503 | 2 | 0.7711 | Interaction of the chromosomal Tn 551 with two thermosensitive derivatives, pS1 and p delta D, of the plasmid pI9789 in Staphylococcus aureus. The plasmid pI9789::Tn552 carries genes conferring resistance to penicillins and to cadmium, mercury and arsenate ions. The presence of Tn551 at one location in the chromosome of Staphylococcus aureus enhances the frequency of suppression of thermosensitivity of replication of the plasmids pS1 and p delta D which are derivatives of pI9789::Tn552. Bacteriophage propagated on the bacteria in which thermosensitivity of replication had been suppressed was used to transduce cadmium resistance to S. aureus PS80N. The cadmium-resistant transductants obtained carried plasmid pS1 or p delta D with a copy of Tn551 inserted into a specific site on pS1 but into several different sites on p delta D. The possible mechanisms of the suppression are discussed. | 1995 | 7758929 |
| 554 | 3 | 0.7704 | VanZ Reduces the Binding of Lipoglycopeptide Antibiotics to Staphylococcus aureus and Streptococcus pneumoniae Cells. vanZ, a member of the VanA glycopeptide resistance gene cluster, confers resistance to lipoglycopeptide antibiotics independent of cell wall precursor modification by the vanHAX genes. Orthologs of vanZ are present in the genomes of many clinically relevant bacteria, including Enterococcus faecium and Streptococcus pneumoniae; however, vanZ genes are absent in Staphylococcus aureus. Here, we show that the expression of enterococcal vanZ paralogs in S. aureus increases the minimal inhibitory concentrations of lipoglycopeptide antibiotics teicoplanin, dalbavancin, oritavancin and new teicoplanin pseudoaglycone derivatives. The reduction in the binding of fluorescently labeled teicoplanin to the cells suggests the mechanism of VanZ-mediated resistance. In addition, using a genomic vanZ gene knockout mutant of S. pneumoniae, we have shown that the ability of VanZ proteins to compromise the activity of lipoglycopeptide antibiotics by reducing their binding is a more general feature of VanZ-superfamily proteins. | 2020 | 32318043 |
| 105 | 4 | 0.7704 | Resistance of the cholera vaccine candidate IEM108 against CTXPhi infection. The cholera toxin (CT) genes ctxAB are carried on a lysogenic phage of Vibrio cholerae, CTXPhi, which can transfer ctxAB between toxigenic and nontoxigenic strains of bacteria. This transfer may pose a problem when live oral cholera vaccine is given to people in epidemic areas, because the toxin genes can be reacquired by the vaccine strains. To address this problem, we have constructed a live vaccine candidate, IEM108, which carries an El Tor-derived rstR gene. This gene encodes a repressor and can render bacterial resistance to CTXPhi infection. In this study, we evaluated the resistance of IEM108 against CTXPhi infection by using a CTXPhi marked for chloramphenicol (CAF) resistance and an in vivo model. We found that the cloned rstR gene rendered IEM108 immune to infection with the marked CTXPhi. In addition, the infection rate of IEM108 was even lower than that of the native CTXPhi-positive strain. These results suggest that the vaccine candidate IEM108 is resistant to infection by CTXPhi. | 2006 | 16343705 |
| 3742 | 5 | 0.7697 | Lipophilic teicoplanin pseudoaglycon derivatives are active against vancomycin- and teicoplanin-resistant enterococci. A selection of nine derivatives of teicoplanin pseudoaglycon were tested in vitro against clinical vancomycin-resistant Enterococcus strains possessing vanA, vanB or both genes. The bacteria were characterized by PCR for the identification of their resistance genes. The tested compounds contain lipoic acid, different carbohydrates and aryl groups as lipophilic moieties. About one-third of the teicoplanin-resistant strains were shown to be susceptible to one or more of the glycopeptide derivatives. | 2017 | 28144040 |
| 110 | 6 | 0.7696 | Resistance to the macrolide antibiotic tylosin is conferred by single methylations at 23S rRNA nucleotides G748 and A2058 acting in synergy. The macrolide antibiotic tylosin has been used extensively in veterinary medicine and exerts potent antimicrobial activity against Gram-positive bacteria. Tylosin-synthesizing strains of the Gram-positive bacterium Streptomyces fradiae protect themselves from their own product by differential expression of four resistance determinants, tlrA, tlrB, tlrC, and tlrD. The tlrB and tlrD genes encode methyltransferases that add single methyl groups at 23S rRNA nucleotides G748 and A2058, respectively. Here we show that methylation by neither TlrB nor TlrD is sufficient on its own to give tylosin resistance, and resistance is conferred by the G748 and A2058 methylations acting together in synergy. This synergistic mechanism of resistance is specific for the macrolides tylosin and mycinamycin that possess sugars extending from the 5- and 14-positions of the macrolactone ring and is not observed for macrolides, such as carbomycin, spiramycin, and erythromycin, that have different constellations of sugars. The manner in which the G748 and A2058 methylations coincide with the glycosylation patterns of tylosin and mycinamycin reflects unambiguously how these macrolides fit into their binding site within the bacterial 50S ribosomal subunit. | 2002 | 12417742 |
| 611 | 7 | 0.7692 | The Staphylococcus aureus FASII bypass escape route from FASII inhibitors. Antimicrobials targeting the fatty acid synthesis (FASII) pathway are being developed as alternative treatments for bacterial infections. Emergence of resistance to FASII inhibitors was mainly considered as a consequence of mutations in the FASII target genes. However, an alternative and efficient anti-FASII resistance strategy, called here FASII bypass, was uncovered. Bacteria that bypass FASII incorporate exogenous fatty acids in membrane lipids, and thus dispense with the need for FASII. This strategy is used by numerous Gram-positive low GC % bacteria, including streptococci, enterococci, and staphylococci. Some bacteria repress FASII genes once fatty acids are available, and "constitutively" shift to FASII bypass. Others, such as the major pathogen Staphylococcus aureus, can undergo high frequency mutations that favor FASII bypass. This capacity is particularly relevant during infection, as the host supplies the fatty acids needed for bacteria to bypass FASII and thus become resistant to FASII inhibitors. Screenings for anti-FASII resistance in the presence of exogenous fatty acids confirmed that FASII bypass confers anti-FASII resistance among clinical and veterinary isolates. Polymorphisms in S. aureus FASII initiation enzymes favor FASII bypass, possibly by increasing availability of acyl-carrier protein, a required intermediate. Here we review FASII bypass and consequences in light of proposed uses of anti-FASII to treat infections, with a focus on FASII bypass in S. aureus. | 2017 | 28728970 |
| 345 | 8 | 0.7692 | Genetic redundancy, proximity, and functionality of lspA, the target of antibiotic TA, in the Myxococcus xanthus producer strain. We recently showed that type II signal peptidase (SPaseII) encoded by lspA is the target of an antibiotic called TA (myxovirescin), which is made by Myxococcus xanthus. SPaseII cleaves the signal peptide during bacterial lipoprotein processing. Bacteria typically contain one lspA gene; however, strikingly, the M. xanthus DK1622 genome contains four (lspA1 to lspA4). Since two of these genes, lspA3 and lspA4, are located in the giant TA biosynthetic gene cluster, we hypothesized they may play a role in TA resistance. To investigate the functions of the four M. xanthus lspA (lspA(Mx)) genes, we conducted sequence comparisons and found that they contained nearly all the conserved residues characteristic of SPaseII family members. Genetic studies found that an Escherichia coli ΔlspA mutation could be complemented by any of the lspA(Mx) genes in an lpp mutant background, but not in an E. coli lpp(+) background. Because Lpp is the most abundant E. coli lipoprotein, these results suggest the M. xanthus proteins do not function as efficiently as the host enzyme. In E. coli, overexpression of each of the LspA(Mx) proteins conferred TA and globomycin resistance, although LspA3 conferred the highest degree of resistance. In M. xanthus, each lspA(Mx) gene could be deleted and was therefore dispensable for growth. However, lspA3 or lspA4 deletion mutants each exhibited a tan phase variation bias, which likely accounts for their reduced-swarming and delayed-development phenotypes. In summary, we propose that all four LspA(Mx) proteins function as SPaseIIs and that LspA3 and LspA4 might also have roles in TA resistance and regulation, respectively. | 2014 | 24391051 |
| 109 | 9 | 0.7691 | Identification of two putative ATP-cassette genes in Encephalitozoon intestinalis. Currently existing chemotherapeutic compounds are limited and few are effective for treating microsporidiosis. It is possible that resistance of Encephalitozoon to some drugs occurs by efflux mechanisms similar to those previously described for mammalian tumour cells, bacteria or protozoal parasites such as Plasmodium, Leishmania and Entamoeba histolytica. The data in the present study suggest that Encephalitozoon intestinalis contains at least one multidrug resistance gene. We report here two complete sequences EiABC1 and EiABC2, encoding different ATP-binding cassette genes from E. intestinalis, including a P-gp. | 2001 | 11730796 |
| 539 | 10 | 0.7685 | A role of ygfZ in the Escherichia coli response to plumbagin challenge. Plumbagin is found in many herbal plants and inhibits the growth of various bacteria. Escherichia coli strains are relatively resistant to this drug. The mechanism of resistance is not clear. Previous findings showed that plumbagin treatment triggered up-regulation of many genes in E. coli including ahpC, mdaB, nfnB, nfo, sodA, yggX and ygfZ. By analyzing minimal inhibition concentration and inhibition zones of plumbagin in various gene-disruption mutants, ygfZ and sodA were found critical for the bacteria to resist plumbagin toxicity. We also found that the roles of YgfZ and SodA in detoxifying plumbagin are independent of each other. This is because of the fact that ectopically expressed SodA reduced the superoxide stress but not restore the resistance of bacteria when encountering plumbagin at the absence of ygfZ. On the other hand, an ectopically expressed YgfZ was unable to complement and failed to rescue the plumbagin resistance when sodA was perturbed. Furthermore, mutagenesis analysis showed that residue Cys228 within YgfZ fingerprint region was critical for the resistance of E. coli to plumbagin. By solvent extraction and HPLC analysis to follow the fate of the chemical, it was found that plumbagin vanished apparently from the culture of YgfZ-expressing E. coli. A less toxic form, methylated plumbagin, which may represent one of the YgfZ-dependent metabolites, was found in the culture supernatant of the wild type E. coli but not in the ΔygfZ mutant. Our results showed that the presence of ygfZ is not only critical for the E coli resistance to plumbagin but also facilitates the plumbagin degradation. | 2010 | 21059273 |
| 536 | 11 | 0.7684 | Thymidylate synthase gene from Lactococcus lactis as a genetic marker: an alternative to antibiotic resistance genes. The potential of the thymidylate synthase thyA gene cloned from Lactococcus lactis subsp. lactis as a possible alternative selectable marker gene to antibiotic resistance markers has been examined. The thyA mutation is a recessive lethal one; thyA mutants cannot survive in environments containing low amounts of thymidine or thymine (such as Luria-Bertani medium) unless complemented by the thyA gene. The cloned thyA gene was strongly expressed in L. lactis subsp. lactis, Escherichia coli, Rhizobium meliloti, and a fluorescent Pseudomonas strain. In addition, when fused to a promoterless enteric lac operon, the thyA gene drove expression of the lac genes in a number of gram-negative bacteria. In transformation experiments with thyA mutants of E. coli and conjugation experiments with thyA mutants of R. meliloti, the lactococcal thyA gene permitted selection of transformants and transconjugants with the same efficiency as did genes for resistance to ampicillin, chloramphenicol, or tetracycline. Starting from the broad-host-range plasmid pGD500, a plasmid, designated pPR602, was constructed which is completely free of antibiotic resistance genes and has the lactococcal thyA gene fused to a promoterless lac operon. This plasmid will permit growth of thyA mutant strains in the absence of thymidine or thymine and has a number of unique restriction sites which can be used for cloning. | 1990 | 2117883 |
| 6363 | 12 | 0.7681 | The effect of tetronasin and monensin on fermentation, microbial numbers and the development of ionophore-resistant bacteria in the rumen. The Gram-negative rumen bacteria Fibrobacter succinogenes S85, Prevotella ruminicola M384 and Veillonella parvula L59 were grown in media containing successively increasing concentrations of the ionophores, monensin and tetronasin. All three species became more resistant to the ionophore with which they were grown. Increased resistance to one ionophore caused increased resistance to the other, and cross-resistance to another ionophore--lasalocid--and an antibiotic--avoparcin. Recovery of tetronasin-resistant bacteria from the rumen of monensin-fed sheep increased and vice versa, indicating that similar cross-resistance occurred in vivo. | 1993 | 8407673 |
| 3726 | 13 | 0.7681 | Presence of antibiotic resistance genes in a sewage treatment plant in Thibodaux, Louisiana, USA. Increasing uses and disposals of antibiotics to the environment have increased emergence of various antibiotic resistance. One of the sources for the spread of antibiotic resistance is wastewater treatment plant, where bacteria and antibiotics can come in contact and can acquire antibiotics resistance. There are very few studies on this subject from a small town sewage treatment plant. Therefore, this study was conducted using raw sewage as well as treated sewage from a sewage treatment plant in Thibodaux in rural southeast Louisiana in USA. Samples were collected monthly from the Thibodaux sewage treatment plant and the presence of antibiotic resistance genes was monitored. The study showed the presence of antibiotic resistance genes in both raw and treated sewage in every month of the study period. The genetic transformation assay showed the successful transformation of methicillin resistant gene, mecA to an antibiotic sensitive Staphylococcus aureus, which became antibiotic resistant within 24h. | 2015 | 25662190 |
| 3748 | 14 | 0.7680 | Vancomycin resistance in Gram-positive bacteria other than Enterococcus spp. This is a review article on vancomycin resistance on gram positive bacteria other than enterococci. Epidemiology of varying resistance, its clinical relevance and therapeutic options in infections caused by vancomycin resistant Listeria spp., Corynebacteria, streptococci and staphylocci are discussed. | 2000 | 10720798 |
| 509 | 15 | 0.7676 | A novel toxoflavin-quenching regulation in bacteria and its application to resistance cultivars. The toxoflavin (Txn), broad host range phytotoxin produced by a variety of bacteria, including Burkholderia glumae, is a key pathogenicity factor of B. glumae in rice and field crops. Two bacteria exhibiting Txn-degrading activity were isolated from healthy rice seeds and identified as Sphingomonas adhaesiva and Agrobacterium sp. respectively. The genes stdR and stdA, encoding proteins responsible for Txn degradation of both bacterial isolates, were identical, indicating that horizontal gene transfer occurred between microbial communities in the same ecosystem. We identified a novel Txn-quenching regulation of bacteria, demonstrating that the LysR-type transcriptional regulator (LTTR) StdR induces the expression of the stdA, which encodes a Txn-degrading enzyme, in the presence of Txn as a coinducer. Here we show that the bacterial StdR(Txn) -quenching regulatory system mimics the ToxR(Txn) -mediated biosynthetic regulation of B. glumae. Substrate specificity investigations revealed that Txn is the only coinducer of StdR and that StdA has a high degree of specificity for Txn. Rice plants expressing StdA showed Txn resistance. Collectively, bacteria mimic the mechanism of Txn biosynthesis regulation, employ it in the development of a Txn-quenching regulatory system and share it with neighbouring bacteria for survival in rice environments full of Txn. | 2021 | 34009736 |
| 3754 | 16 | 0.7674 | Cancer departments as a source of resistant bacteria and fungi? Antimicrobial resistance increases worldwide. Among many factors, such as clonal spread of genes of resistance among and intra species, local epidemiology, nosocomial transmission, also consumption of antimicrobials may be responsible. Cancer departments, mainly in centers treating hematologic malignancies and organizing bone marrow transplantation (BMT) are known to have extensive consumption of either prophylactically or therapeutically administered antibiotics and antifungals. It is worthy to remember, that first strains of quinolone resistant E. coli, vancomycin resistant enterococci and staphylococci and fluconazol-resistant Candida albicans appeared in the patients treated for cancer with antineoplastic chemotherapy, resulting in profound granulocytopenia. Therefore, assessment of risks of antibiotic prophylaxis with quinolones and azoles and extensive use of empiric therapy with glycopeptides and polyenes needs to be considered. Intensive prophylactic strategies should be limited to group of high risk, leukemic patients or BMT recipients. | 1999 | 10355526 |
| 3756 | 17 | 0.7673 | Ecological antibiotic policy. Development of resistance to antibiotics is a major problem worldwide. The normal oropharyngeal flora, the intestinal flora and the skin flora play important roles in this development. Within a few days after the onset of antibiotic therapy, resistant Escherichia coli, Haemophilus influenzae and Staphylococcus epidermidis can be detected in the normal flora of volunteers or patients. Horizontal spread of the resistance genes to other species, e.g. Salmonella spp., Staphylococcus aureus and Streptococcus pneumoniae, occurs by conjugation or transformation. An ecologically sound antibiotic policy favours the use of antibiotics with little or no impact on the normal flora. Prodrug antibiotics which are not active against the bacteria in the mouth and the intestine (before absorption) and which are not excreted to a significant degree via the intestine, saliva or skin are therefore preferred. Prodrugs such as pivampicillin, bacampicillin, pivmecillinam and cefuroxime axetil are favourable from an ecological point of view. Experience from Scandinavia supports this, since resistance to mecillinam after 20 years of use is low (about 5%) and stable. | 2000 | 11051626 |
| 3755 | 18 | 0.7673 | Ecological antibiotic policy. Development of resistance to antibiotics is a major problem worldwide. The normal oropharyngeal flora, the intestinal flora and the skin flora play important roles in this development. Within a few days after the onset of antibiotic therapy, resistant Escherichia coli, Haemophilus influenzae and Staphylococcus epidermidis can be detected in the normal flora of volunteers or patients. Horizontal spread of the resistance genes to other species, e.g. SALMONELLA: spp., Staphylococcus aureus and Streptococcus pneumoniae, occurs by conjugation or transformation. An ecologically sound antibiotic policy favours the use of antibiotics with little or no impact on the normal flora. Prodrug antibiotics which are not active against the bacteria in the mouth and the intestine (before absorption) and which are not excreted to a significant degree via the intestine, saliva or skin are therefore preferred. Prodrugs such as pivampicillin, bacampicillin, pivmecillinam and cefuroxime axetil are favourable from an ecological point of view. Experience from Scandinavia supports this, since resistance to mecillinam after 20 years of use is low (about 5%) and stable. | 2000 | 10969054 |
| 3753 | 19 | 0.7668 | Flavophospholipol use in animals: positive implications for antimicrobial resistance based on its microbiologic properties. Bambermycin (flavophospholipol) is a phosphoglycolipid antimicrobial produced by various strains of Streptomyces. It is active primarily against Gram-positive bacteria because of inhibition of transglycosylase and thus of cell wall synthesis. Bambermycin is used as a feed additive growth promoter in cattle, pigs, chickens, and turkeys, but has no therapeutic use in humans or animals. Flavophospholipol is known to suppress certain microorganisms (e.g., Staphylococcus spp. and Enterococcus faecalis) and thus contributes to an improved equilibrium of the gut microflora providing a barrier to colonization with pathogenic bacteria and resultant improved weight gain and feed conversion. Flavophospholipol has also been shown to decrease the frequency of transferable drug resistance among Gram-negative enteropathogens and to reduce the shedding of pathogenic bacteria such as Salmonella in pigs, calves, and chickens. Plasmid-mediated resistance to bambermycin has not been described. Likewise, cross-resistance among bacteria between bambermycin and penicillin, tetracycline, streptomycin, erythromycin, or oleandromycin has not been observed. This brief review summarizes the antimicrobial properties of bambermycin, in particular, its potentially favorable role in decreasing antimicrobial resistance. | 2006 | 16698216 |