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33300.9720Mutants of Escherichia coli altered in both genes coding for the elongation factor Tu. Genetic analysis of a mutant of Escherichia coli resistant to the antibiotic mocimycin is presented. This resistance is due to alterations in both tuf genes coding for the elongation factor Tu. Mocimycin resistance is recessive. Bacteria carryong only one tuf gene from the resistant mutant are still mocimycin sensitive. If the mutant gene is the tufA gene, the seisitive cells can be made resistant through inactivation of the tufB gene by insertion of the bacteriophage milliunits genome. Conditional mocimycin-resistant mutants ban also be isolated when the tufB gene is altered by an amber or a temperature-sensitive mutation. When only the tufB allele from the original mocimycin-resistant mutant is present, inactivation of the wild-type tufA gene fails to give viable mocimycin-resistant progeny. We conclude that the tufA mutant allele codes for a functional mocimycin-resistant EF-Tu, whereas the mutant tufB gene does not code for a functional product.1978360222
605010.9708Vancomycin resistance factor of Lactobacillus rhamnosus GG in relation to enterococcal vancomycin resistance (van) genes. Lactobacillus rhamnosus GG (ATCC 53103) is a probiotic strain used in fermented dairy products in many countries and is also used as a food supplement in the form of freeze-dried powder. The relationship of the vancomycin resistance factor in L. rhamnosus GG and the vancomycin resistance (van) genes of Enterococcus faecalis and E. faecium were studied using polymerase chain reaction (PCR), Southern hybridization and conjugation methods. Our results show that the vancomycin resistance determinant in L. rhamnosus GG is not closely related to enterococcal van genes, since no PCR product was amplified in L. rhamnosus GG with any of the three sets of vanA primers used, and enterococcal vanA, vanB, vnH, vanX, vanZ, vanY, vanS and vanR genes did not hybridize with DNA of L. rhamnosus GG. This strain does not contain plasmids and transfer of chromosomal vancomycin resistance determinant from L. rhamnosus GG to enterococcal species was not detected. Our results are in accordance with previous findings of intrinsically vancomycin-resistant lactic acid bacteria.19989706787
365320.9707Erythromycin-resistant lactic acid bacteria in the healthy gut of vegans, ovo-lacto vegetarians and omnivores. Diet can affect the diversity and composition of gut microbiota. Usage of antibiotics in food production and in human or veterinary medicine has resulted in the emergence of commensal antibiotic resistant bacteria in the human gut. The incidence of erythromycin-resistant lactic acid bacteria (LAB) in the feces of healthy vegans, ovo-lacto vegetarians and omnivores was analyzed. Overall, 155 LAB were isolated and characterized for their phenotypic and genotypic resistance to erythromycin. The isolates belonged to 11 different species within the Enterococcus and Streptococcus genera. Enterococcus faecium was the dominant species in isolates from all the dietary categories. Only 97 out of 155 isolates were resistant to erythromycin after Minimum Inhibitory Concentration (MIC) determination; among them, 19 isolates (7 from vegans, 4 from ovo-lacto vegetarians and 8 from omnivores) carried the erm(B) gene. The copresence of erm(B) and erm(A) genes was only observed in Enterococcus avium from omnivores. Moreover, the transferability of erythromycin resistance genes using multidrug-resistant (MDR) cultures selected from the three groups was assessed, and four out of six isolates were able to transfer the erm(B) gene. Overall, isolates obtained from the omnivore samples showed resistance to a greater number of antibiotics and carried more tested antibiotic resistance genes compared to the isolates from ovo-lacto vegetarians and vegans. In conclusion, our results show that diet does not significantly affect the occurrence of erythromycin-resistant bacteria and that commensal strains may act as a reservoir of antibiotic resistance (AR) genes and as a source of antibiotic resistance spreading.201931374082
539030.9706Presence of erythromycin and tetracycline resistance genes in lactic acid bacteria from fermented foods of Indian origin. Lactic acid bacteria (LAB) resistant to erythromycin were isolated from different food samples on selective media. The isolates were identified as Enterococcus durans, Enterococcus faecium, Enterococcus lactis, Enterococcus casseliflavus, Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus fermentum, Pediococcus pentosaceus and Leuconostoc mesenteroides. Of the total 60 isolates, 88 % harbored the ermB gene. The efflux gene msrA was identified in E. faecium, E. durans, E. lactis, E. casseliflavus, P. pentosaceus and L. fermentum. Further analysis of the msrA gene by sequencing suggested its homology to msrC. Resistance to tetracycline due to the genes tetM, tetW, tetO, tetK and tetL, alone or in combination, were identified in Lactobacillus species. The tetracycline efflux genes tetK and tetL occurred in P. pentosaceus and Enterococcus species. Since it appeared that LAB had acquired these genes, fermented foods may be a source of antibiotic resistance.201222644346
586440.9703Characterization of the tetracycline resistance plasmid pMD5057 from Lactobacillus plantarum 5057 reveals a composite structure. The 10,877bp tetracycline resistance plasmid pMD5057 from Lactobacillus plantarum 5057 was completely sequenced. The sequence revealed a composite structure containing DNA from up to four different sources. The replication region had homology to other plasmids of lactic acid bacteria while the tetracycline resistance region, containing a tet(M) gene, had high homology to sequences from Clostridium perfringens and Staphylococcus aureus. Within the tetracycline resistance region a Lactobacillus IS-element was found. The remaining part of the plasmid contained three open reading frames with unknown functions. The composite structure with several truncated genes suggests a recent assembly of the plasmid. This is the first sequence of an antibiotic resistance plasmid isolated from L. plantarum.200212383727
599150.9702Transferable plasmid-mediated antibiotic resistance in Listeria monocytogenes. A strain of Listeria monocytogenes, isolated from a patient with meningoencephalitis, was resistant to chloramphenicol, erythromycin, streptomycin, and tetracycline. The genes conferring resistance to these antibiotics were carried by a 37-kb plasmid, pIP811, that was self-transferable to other L monocytogenes cells, to enterococci-streptococci, and to Staphylococcus aureus. The efficacy of transfer and the stability of pIP811 were higher in enterococci-streptococci than in the other gram-positive bacteria. As indicated by nucleic acid hybridisation, the genes in pIP811 conferring resistance to chloramphenicol, erythromycin, and streptomycin were closely related to plasmid-borne determinants that are common in enterococci-streptococci. Plasmid pIP811 shared extensive sequence homology with pAM beta 1, the prototype broad host range resistance plasmid in these two groups of gram-positive cocci. These results suggest that emergence of multiple antibiotic resistance in Listeria spp is due to acquisition of a replicon originating in enterococci-streptococci. The dissemination of resistance to other strains of L monocytogenes is likely.19901972210
10960.9700Identification 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.200111730796
605670.9699Virulence, antibiotic resistance and biogenic amines of bacteriocinogenic lactococci and enterococci isolated from goat milk. The present study aimed to investigate the virulence, antibiotic resistance and biogenic amine production in bacteriocinogenic lactococci and enterococci isolated from goat milk in order to evaluate their safety. Twenty-nine bacteriocinogenic lactic acid bacteria (LAB: 11 Lactococcus spp., and 18 Enterococcus spp.) isolated from raw goat milk were selected and subjected to PCR to identify gelE, cylA, hyl, asa1, esp, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc genes. The expression of virulence factors (gelatinase, hemolysis, lipase, DNAse, tyramine, histamine, putrescine) in different incubation temperatures was assessed by phenotypic methods, as well as the resistance to vancomycin, gentamicin, chloramphenicol, ampicillin and rifampicin (using Etest®). The tested isolates presented distinct combinations of virulence related genes, but not necessarily the expression of such factors. The relevance of identifying virulence-related genes in bacteriocinogenic LAB was highlighted, demanding for care in their usage as starter cultures or biopreservatives due to the possibility of horizontal gene transfer to other bacteria in food systems.201424960293
365480.9699Distribution of Antibiotic Resistance Genes in the Saliva of Healthy Omnivores, Ovo-Lacto-Vegetarians, and Vegans. Food consumption allows the entrance of bacteria and their antibiotic resistance (AR) genes into the human oral cavity. To date, very few studies have examined the influence of diet on the composition of the salivary microbiota, and even fewer investigations have specifically aimed to assess the impact of different long-term diets on the salivary resistome. In this study, the saliva of 144 healthy omnivores, ovo-lacto-vegetarians, and vegans were screened by nested PCR for the occurrence of 12 genes conferring resistance to tetracyclines, macrolide-lincosamide-streptogramin B, vancomycin, and β-lactams. The tet(W), tet(M), and erm(B) genes occurred with the highest frequencies. Overall, no effect of diet on AR gene distribution was seen. Some differences emerged at the recruiting site level, such as the higher frequency of erm(C) in the saliva of the ovo-lacto-vegetarians and omnivores from Bologna and Turin, respectively, and the higher occurrence of tet(K) in the saliva of the omnivores from Bologna. A correlation of the intake of milk and cheese with the abundance of tet(K) and erm(C) genes was seen. Finally, when the occurrence of the 12 AR genes was evaluated along with geographical location, age, and sex as sources of variability, high similarity among the 144 volunteers was seen.202032961926
546190.9697Molecular characteristics and comparative genomics analysis of a clinical Enterococcus casseliflavus with a resistance plasmid. PURPOSE: The aim of this work was to investigate the molecular characterization of a clinical Enterococcus casseliflavus strain with a resistance plasmid. MATERIALS AND METHODS: En. casseliflavus EC369 was isolated from a patient in a hospital in southern China. The minimum inhibitory concentration was found by means of the agar dilution method to determine the antimicrobial susceptibilities of the strains. Whole-genome sequencing and comparative genomics analysis were performed to analyze the mechanism of antibiotic resistance and the horizontal gene transfer of the resistance gene-related mobile genetic elements. RESULTS: En. casseliflavus EC369 showed resistance to erythromycin, kanamycin, and streptomycin, but was susceptible to vancomycin, ampicillin, and streptothricin and other antimicrobials. There were six resistance genes (aph3', ant6, bla, sat4, and two ermBs) carried by a transposon identified on the plasmid pEC369 and a complete resistance gene cluster of vancomycin and a tet (M) gene encoded on the chromosome. This is the first complete plasmid sequence reported in clinically isolated En. casseliflavus. The plasmid with the greatest sequence identity with pEC369 was the plasmid of Enterococcus sp. FDAARGOS_375, followed by the plasmids of Enterococcus faecium strains F12085 and pRE25, whereas the sequence with the greatest identity to the resistance genes carrying a transposon of pEC369 was on the chromosome of Staphylococcus aureus strain GD1677. CONCLUSION: The resistance profiles of En. casseliflavus EC369 might contribute to the resistance genes encoded on the plasmid. The fact that the most similar sequence to the transposon carrying resistance genes of pEC369 was encoded in the chromosome of a S. aureus strain provides insights into the mechanism of dissemination of multidrug resistance between bacteria of different species or genera through horizontal gene transfer.201830464559
5988100.9696Enterococcal vanB resistance locus in anaerobic bacteria in human faeces. While developing a rapid method to detect carriers of vancomycin-resistant enterococci (VRE), we found the vanB gene by PCR in 13 of 50 human faecal specimens that did not contain culturable VRE. Passaging under antibiotic selection allowed us to isolate two species of anaerobic bacteria that were vanB PCR positive, vancomycin resistant, and teicoplanin sensitive. Sequence analysis of the 16S rRNA genes showed that one isolate resembled Eggerthella lenta (98% identity), and the other Clostridium innocuum (92% identity). Southern hybridisation and nucleotide sequencing showed a vanB locus homologous to that in VRE. We propose that vanB resistance in enterococci might arise from gene transfer in the human bowel.200111265957
3742110.9696Lipophilic 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.201728144040
6131120.9695Draft Genome Sequence of Eggerthia catenaformis Strain MAR1 Isolated from Saliva of Healthy Humans. Here, we report the draft genome sequence of Eggerthia catenaformis MAR1 isolated during a screen for d-cycloserine-resistant bacteria from the saliva of healthy humans. Analysis of the genome reveals that the strain has the potential to be a human pathogen and carries genes related to virulence and antibiotic resistance.201728705984
3665130.9694Vancomycin-resistant gram-positive cocci isolated from the saliva of wild songbirds. We analyzed highly vancomycin-resistant Gram-positive bacteria isolated from the saliva of migratory songbirds captured, sampled, and released from a bird-banding station in western Kansas. Individual bacterial isolates were identified by partial 16S rRNA sequencing. Most of the bacteria in this study were shown to be Staphylococcus succinus with the majority being isolated from the American Robin. Some of these bacteria were shown to carry vanA, vanB, and vanC vancomycin-resistance genes and have the ability to form biofilms. One of the van gene-carrying isolates is also coagulase positive, which is normally considered a virulence factor. Other organisms isolated included Staphylococcus saprophyticus as well as Enterococcus gallinarum. Given the wide range of the American Robin and ease of horizontal gene transfer between Gram-positive cocci, we postulate that these organisms could serve as a reservoir of vancomycin-resistance genes capable of transferring to human pathogens.201323224296
9869140.9694Detection of variants of the pRAS3, pAB5S9, and pSN254 plasmids in Aeromonas salmonicida subsp. salmonicida: multidrug resistance, interspecies exchanges, and plasmid reshaping. The ubiquitous water-borne Gram-negative bacterium Aeromonas salmonicida subsp. salmonicida is the causative agent of furunculosis, a worldwide disease in fish farms. Plasmids carrying antibiotic resistance genes have already been described for this bacterium. The aim of the present study was to identify and characterize additional multidrug resistance plasmids in A. salmonicida subsp. salmonicida. We sequenced the plasmids present in two multiple antibiotic-resistant isolates using high-throughput technologies. We also investigated 19 other isolates with various multidrug resistance profiles by genotyping PCR and assessed their resistance to tetracycline. We identified variants of the pAB5S9 and pSN254 plasmids that carry several antibiotic resistance genes and that have been previously reported in bacteria other than A. salmonicida subsp. salmonicida, which suggests a high level of interspecies exchange. Genotyping analyses and the antibiotic resistance profiles of the 19 other isolates support the idea that multiple versions of pAB5S9 and pSN254 exist in A. salmonicida subsp. salmonicida. We also identified variants of the pRAS3 plasmid. The present study revealed that A. salmonicida subsp. salmonicida harbors a wide variety of plasmids, which suggests that this ubiquitous bacterium may contribute to the spread of antibiotic resistance genes in the environment.201425267667
3567150.9694Cloning and sequence analysis of ermQ, the predominant macrolide-lincosamide-streptogramin B resistance gene in Clostridium perfringens. The erythromycin resistance determinant from Clostridium perfringens JIR100 has been cloned, sequenced, and shown to be expressed in Escherichia coli. An open reading frame with sequence similarity to erm genes from other bacteria was identified and designated the ermQ gene. On the basis of comparative sequence analysis, it was concluded that the ermQ gene represented a new Erm hybridization class, designated ErmQ. Genes belonging to the ErmQ class were found to be widespread in C. perfringens, since 30 of 38 macrolide-lincosamide-streptogramin B-resistant C. perfringens strains, from diverse sources, hybridized to an ermQ-specific gene probe. The ermQ gene therefore represents the most common erythromycin resistance determinant in C. perfringens.19948067735
6051160.9693Antibiotic susceptibility of different lactic acid bacteria strains. Five lactic acid bacteria (LAB) strains belonging to species Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis and Streptococcus thermophilus were tested for their susceptibility to 27 antibiotics. The minimum inhibitory concentrations of each antimicrobial were determined using a microdilution test. Among the strains a high susceptibility was detected for most of the cell-wall synthesis inhibitors (penicillins, cefoxitin and vancomycin) and resistance toward inhibitors of DNA synthesis (trimethoprim/sulfonamides and fluoroquinolones). Generally, the Lactobacillus strains were inhibited by antibiotics such as chloramphenicol, erythromycin and tetracycline at breakpoint levels lower or equal to the levels defined by the European Food Safety Authority. Despite the very similar profile of S. thermophilus LC201 to lactobacilli, the detection of resistance toward erythromycin necessitates the performance of additional tests in order to prove the absence of transferable resistance genes.201122146692
5392170.9693Characterization and transfer of antibiotic resistance in lactic acid bacteria from fermented food products. The study provides phenotypic and molecular analyses of the antibiotic resistance in lactic acid bacteria (LAB) from fermented foods in Xi'an, China. LAB strains (n = 84) belonging to 16 species of Lactobacillus (n = 73), and Streptococcus thermophilus (n = 11) were isolated and identified by sequencing their 16S rRNA gene. All strains were susceptible to ampicillin, bacitracin, and cefsulodin, and intrinsically resistant to nalidixic acid, kanamycin, and vancomycin (except L. bulgaricus, L. acidophilus, and S. thermophilus, which were susceptible to vancomycin). Some strains had acquired resistance for penicillin (n = 2), erythromycin (n = 9), clindamycin (n = 5), and tetracycline (n = 14), while resistance to gentamycin, ciprofloxacin, streptomycin, and chloramphenicol was species dependent. Minimum inhibitory concentrations presented in this study will help to review microbiological breakpoints for some of the species of Lactobacillus. The erm(B) gene was detected from two strains of each of L. fermentum and L. vaginalis, and one strain of each of L. plantarum, L. salivarius, L. acidophilus, L. animalis, and S. thermophilus. The tet genes were identified from 12 strains of lactobacilli from traditional foods. This is the first time, the authors identified tet(S) gene from L. brevis and L. kefiri. The erm(B) gene from L. fermentum NWL24 and L. salivarius NWL33, and tet(M) gene from L. plantarum NWL22 and L. brevis NWL59 were successfully transferred to Enterococcus faecalis 181 by filter mating. It was concluded that acquired antibiotic resistance is well dispersed in fermented food products in Xi'an, China and its transferability to other genera should be monitored closely.201121212956
5399180.9693Characterisation and transferability of antibiotic resistance genes from lactic acid bacteria isolated from Irish pork and beef abattoirs. Lactic acid bacteria isolated from Irish pork and beef abattoirs were analysed for their susceptibility to antimicrobials. Thirty-seven isolates (12 enterococci, 10 lactobacilli, 8 streptococci, 3 lactococci, 2 Leuconostoc, and 2 pediococci) were examined for phenotypic resistance using the E-test and their minimum inhibitory concentration to a panel of six antibiotics (ampicillin, chloramphenicol, erythromycin, streptomycin, tetracycline, and vancomycin) was recorded. The corresponding genetic determinants responsible were characterised by PCR. Also, the transferability of these resistance markers was assessed in filter mating assays. Of the 37 isolates, 33 were found to be resistant to one or more antibiotics. All strains were susceptible to ampicillin and chloramphenicol. The erm(B) and msrA/B genes were detected among the 11 erythromycin-resistant strains of enterococci, lactobacilli, and streptococci. Two tetracycline-resistant strains, Lactobacillus plantarum and Leuconostoc mesenteroides spp., contained tet(M) and tet(S) genes respectively. Intrinsic streptomycin resistance was observed in lactobacilli, streptococci, lactococci and Leuconostoc species; none of the common genetic determinants (strA, strB, aadA, aadE) were identified. Four of 10 strains of Enterococcus faecium were resistant to vancomycin; however, no corresponding genetic determinants for this phenotype were identified. Enterococcus faecalis strains were susceptible to vancomycin. L. plantarum, L. mesenteroides and Pediococcus pentosaceus were intrinsically resistant to vancomycin. Transfer of antibiotic resistance determinants was demonstrated in one strain, wherein the tet(M) gene of L. plantarum (23) isolated from a pork abattoir was transferred to Lactococcus lactis BU-2-60 and to E. faecalis JH2-2. This study identified the presence of antibiotic resistance markers in Irish meat isolates and, in one example, resistance was conjugally transferred to other LAB strains.201020074643
6140190.9692Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells. Lactobacillus plantarum KLDS1.0391 is a probiotic strain isolated from the traditional fermented dairy products and identified to produce bacteriocin against Gram-positive and Gram-negative bacteria. Previous studies showed that the strain has a high resistance to gastrointestinal stress and has a high adhesion ability to the intestinal epithelial cells (Caco-2). We reported the entire genome sequence of this strain, which contains a circular 2,886,607-bp chromosome and three circular plasmids. Genes, which are related to the biosynthesis of bacteriocins, the stress resistance to gastrointestinal tract environment and adhesive performance, were identified. Whole genome sequence of Lactobacillus plantarum KLDS1.0391 will be helpful for its applications in food industry.201728676278