scholarly journals Two Different Tetracycline Resistance Mechanisms, Plasmid-Carried tet(L) and Chromosomally Located Transposon-Associated tet(M), Coexist in Lactobacillus sakei Rits 9

2008 ◽  
Vol 74 (5) ◽  
pp. 1394-1401 ◽  
Author(s):  
Mohammed Salim Ammor ◽  
Miguel Gueimonde ◽  
Morten Danielsen ◽  
Monique Zagorec ◽  
Angela H. A. M. van Hoek ◽  
...  
Keyword(s):  
Efflux Pump ◽  
Expression Patterns ◽  
Starter Culture ◽  
Meat Products ◽  
Tetracycline Resistance ◽  
Raw Milk ◽  
Lactobacillus Sakei ◽  
M Gene ◽  
Resistance Level ◽  
Gene Coding

ABSTRACT Lactobacillus sakei is extensively used as functional starter culture in fermented meat products. One of the safety criteria of a starter culture is the absence of potentially transferable antibiotic resistance determinants. However, tetracycline-resistant L. sakei strains have already been observed. In this paper, we show that tetracycline resistance in L. sakei Rits 9, a strain isolated from Italian Sola cheese made from raw milk, is mediated by a transposon-associated tet(M) gene coding for a ribosomal protection protein and a plasmid-carried tet(L) gene coding for a tetracycline efflux pump. pLS55, the 5-kb plasmid carrying the tet(L) gene, is highly similar to the pMA67 plasmid recently described for Paenibacillus larvae, a species pathogenic to honeybees. pLS55 could be transferred by electroporation into the laboratory strain L. sakei 23K. While the L. sakei 23K transformant containing pLS55 displayed an intermediate tetracycline resistance level (MIC, <32 μg/ml), L. sakei Rits 9, containing both tetracycline-resistant determinants, had a MIC of <256 μg/ml, suggesting that Tet L and Tet M confer different levels of resistance in L. sakei. Remarkably, in the absence of tetracycline, a basal expression of both genes was detected for L. sakei Rits 9. In addition, subinhibitory concentrations of tetracycline affected the expression patterns of tet(M) and tet(L) in different ways: the expression of tet(M) was induced only at high tetracycline concentrations, whereas the expression of tet(L) was up-regulated at lower concentrations. This is the first time that two different mechanisms conferring resistance to tetracycline are characterized for the same strain of a lactic acid bacterium.

scholarly journals Identification and Transferability of Tetracycline Resistance in Streptococcus thermophilus during Milk Fermentation, Storage, and Gastrointestinal Transit

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 65
Author(s):  
Armin Tarrah ◽  
Shadi Pakroo ◽  
Viviana Corich ◽  
Alessio Giacomini
Keyword(s):  
Efflux Pump ◽  
Acquired Resistance ◽  
Gastrointestinal Transit ◽  
Tetracycline Resistance ◽  
Lactobacillus Delbrueckii ◽  
Genomic Islands ◽  
Resistant Bacteria ◽  
Human Pathogens ◽  
Resistance Level ◽  
Milk Fermentation

The existence of antibiotic-resistant bacteria in food products, particularly those carrying acquired resistance genes, has increased concerns about the transmission of these genes from beneficial microbes to human pathogens. In this study, we evaluated the antibiotic resistance-susceptibility patterns of 16 antibiotics in eight S. thermophilus strains, whose genome sequence is available, using phenotypic and genomic approaches. The minimal inhibitory concentration values collected revealed intermediate resistance to aminoglycosides, whereas susceptibility was detected for different classes of β-lactams, quinolones, glycopeptide, macrolides, and sulfonamides in all strains. A high tetracycline resistance level has been detected in strain M17PTZA496, whose genome analysis indicated the presence of the tet(S) gene and the multidrug and toxic compound extrusion (MATE) family efflux pump. Moreover, an in-depth genomic analysis revealed genomic islands and an integrative and mobilizable element (IME) in the proximity of the gene tet(S). However, despite the presence of a prophage, genomic islands, and IME, no horizontal gene transfer was detected to Lactobacillus delbrueckii subsp. lactis DSM 20355 and Lactobacillusrhamnosus GG during 24 h of skim milk fermentation, 2 weeks of refrigerated storage, and 4 h of simulated gastrointestinal transit.

scholarly journals Intra- and Interspecies Conjugal Transfer of Tn916-Like Elements from Lactococcus lactis In Vitro and In Vivo

2009 ◽  
Vol 75 (19) ◽  
pp. 6352-6360 ◽  
Author(s):  
Joanna Boguslawska ◽  
Joanna Zycka-Krzesinska ◽  
Andrea Wilcks ◽  
Jacek Bardowski
Keyword(s):  
Antibiotic Resistance ◽  
Lactococcus Lactis ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Raw Milk ◽  
M Gene ◽  
Transfer Resistance

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.

scholarly journals Presence of the Tet M Determinant in a Clinical Isolate of Acinetobacter baumannii

2003 ◽  
Vol 47 (7) ◽  
pp. 2310-2312 ◽  
Author(s):  
Anna Ribera ◽  
Joaquim Ruiz ◽  
Jordi Vila
Keyword(s):  
Staphylococcus Aureus ◽  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Efflux Pump ◽  
Tetracycline Resistance ◽  
M Gene ◽  
Gene Encoding ◽  
Ribosomal Protection

ABSTRACT The tet(M) gene encodes a protein which is related to tetracycline ribosomal protection, one of the mechanisms of tetracycline resistance. A tet(M) gene that is 100% homologous to the tet(M) gene of Staphylococcus aureus has been found in a clinical isolate of Acinetobacter baumannii, which also carries the tet(A) gene encoding a tetracycline efflux pump.

Growth, nisA Gene Expression, and In Situ Activity of Novel Lactococcus lactis subsp. cremoris Costarter Culture in Commercial Hard Cheese Production

2017 ◽  
Vol 80 (12) ◽  
pp. 2137-2146 ◽  
Author(s):  
Dimitrios Noutsopoulos ◽  
Athanasia Kakouri ◽  
Eleftheria Kartezini ◽  
Dimitrios Pappas ◽  
Efstathios Hatziloukas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lactococcus Lactis ◽  
Starter Culture ◽  
Fold Increase ◽  
Raw Milk ◽  
Good Growth ◽  
Lactococcus Lactis Subsp ◽  
Quantitative Expression ◽  
Hard Cheese

ABSTRACT This study evaluated in situ expression of the nisA gene by an indigenous, nisin A–producing (NisA+) Lactococcus lactis subsp. cremoris raw milk genotype, represented by strain M78, in traditional Greek Graviera cheeses under real factory-scale manufacturing and ripening conditions. Cheeses were produced with added a mixed thermophilic and mesophilic commercial starter culture (CSC) or with the CSC plus strain M78 (CSC+M78). Cheeses were sampled after curd cooking (day 0), fermentation of the unsalted molds for 24 h (day 1), brining (day 7), and ripening of the brined molds (14 to 15 kg each) for 30 days in a fully controlled industrial room (16.5°C; 91% relative humidity; day 37). Total RNA was directly extracted from the cheese samples, and the expression of nisA gene was evaluated by real-time reverse transcription PCR (qRT-PCR). Agar overlay and well diffusion bioassays were correspondingly used for in situ detection of the M78 NisA+ colonies in the cheese agar plates and antilisterial activity in whole-cheese slurry samples, respectively. Agar overlay assays showed good growth (&gt;8 log CFU/g of cheese) of the NisA+ strain M78 in coculture with the CSC and vice versa. The nisA expression was detected in CSC+M78 cheese samples only, with its expression levels being the highest (16-fold increase compared with those of the control gene) on day 1, followed by significant reduction on day 7 and almost negligible expression on day 37. Based on the results, certain intrinsic and mainly implicit hurdle factors appeared to reduce growth prevalence rates and decrease nisA gene expression, as well as the nisin A–mediated antilisterial activities of the NisA+ strain M78 postfermentation. To our knowledge, this is the first report on quantitative expression of the nisA gene in a Greek cooked hard cheese during commercial manufacturing and ripening conditions by using a novel, rarely isolated, indigenous NisA+ L. lactis subsp. cremoris genotype as costarter culture.

scholarly journals Features of Lactobacillus sakei isolated from Italian sausages: focus on strains from Ventricina del Vastese

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Carmela Amadoro ◽  
Franca Rossi ◽  
Michele Piccirilli ◽  
Giampaolo Colavita
Keyword(s):  
Meat Products ◽  
Lactobacillus Sakei ◽  
Bacterial Isolates ◽  
Chain Reaction ◽  
Spontaneous Fermentation ◽  
Meat Extract ◽  
Fermented Sausages ◽  
Polymerase Chain ◽  
High Diversity

In this study bacterial isolates from <em>Ventricina del Vastese</em> sausage, previously identified as <em>Lactobacillus (L.) sakei</em>, were characterised genotypically, physiologically and on the basis of some technologically relevant traits. A total of 70 <em>L. sakei</em> isolates from sausages manufactured with spontaneous fermentation in the same producing plant were taken into account. Six genotypic groups were distinguished on the basis of Rep-polymerase chain reaction with the GTG<sub>5</sub> primer, some of which were found only in the sausages ripened at temperatures lower than 10°C for the first two months and lower than 16°C for the remaining three months, according to the traditional ripening process. Six strains were selected as representative of the genotypic profiles and further characterised. A high diversity in their fermentation profiles was observed, and different groups were separated on the basis of growth and acidifying capacity in meat extract. None of the strains produced histamine or tyramine <em>in vitro</em>. One strain was able to slightly inhibit <em>Listeria (L.) monocytogenes</em> and <em>L. innocua</em> and all six strains were able to slightly inhibit <em>Enterobacteriaceae</em> isolated from <em>Ventricina del Vastese</em> sausages <em>in vitro</em>. Results showed that most <em>L. sakei</em> strains can have a role in improving the safety of low acidity fermented sausages, even though a limited acidifying capacity was observed in a meat-like substrate, and that <em>L. sakei</em> strains able to produce biogenic amines are unlikely to occur in spontaneously fermented meat products.

scholarly journals Molecular Detection of Staphylococcal Enterotoxins and mecA Genes Products in Selected Food Samples Collected from Different Areas in Khartoum State

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mohammed Yahya Ahmed ◽  
Hashim Abdalbagi Ali ◽  
Babbiker Mohammed Taher Gorish ◽  
Sara Omer Ali ◽  
Eman Saif Aldein Abdalrhim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Meca Gene ◽  
Food Poisoning ◽  
Meat Products ◽  
Low Frequency ◽  
Raw Milk ◽  
Food Samples ◽  
Increased Risk ◽  
Enterotoxin B ◽  
Staphylococcus Aureus Enterotoxins

Staphylococcal food poisoning is an intoxication that results from the consumption of improperly prepared or stored foods containing sufficient amounts of one or more preformed S. aureus enterotoxins. Nowadays, many researchers worldwide noted an emergence of resistant strains such as Staphylococci particularly for the antibiotic methicillin. Therefore, this study was aimed to determine the existence of Staphylococcus aureus and its enterotoxins, mecA genes, in selected food samples. A total of 400 selected food samples were collected from different areas in Khartoum State. The selected foods included cheese, meat products, fish, and raw milk. One hundred samples from each type of food were cultivated, and the resultant growth yielded 137 (34.25%) S. aureus, 126 (31.5%) bacteria other than S. aureus, and 137 (34.25%) yielded no growth. Eighty-four of the 137 S. aureus isolates were randomly selected and tested for the presence of mecA and enterotoxin genes. The oxacillin sensitivity test showed that 15 (11%) of 137 S. aureus isolates were oxacillin resistant. The PCR assay showed that the mecA gene was detected in 15 of 84 (17%) S. aureus isolates. Simultaneously, only 2 (2.385%) out of 84 S. aureus isolates showed an enterotoxin B gene product. There was a relatively moderate prevalence of methicillin-resistant Staphylococcus aureus with very low frequency of enterotoxin B gene in different kinds of selected food samples collected from Khartoum State. These findings elucidate the increased risk on public in Khartoum being affected by Staphylococcal food poisoning upon consumption of dairy or meat products prepared in unhygienic conditions that could lead to intoxication by Staphylococcus aureus enterotoxins.

Efflux pump gene expression study using RNA-seq in multidrug-resistant TB

2021 ◽  
Vol 25 (12) ◽  
pp. 974-981
Author(s):  
J. J. Lee ◽  
H. Y. Kang ◽  
W-I. Lee ◽  
S. Y. Cho ◽  
Y. J. Kim ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Efflux Pump ◽  
Expression Patterns ◽  
Resistance Mechanism ◽  
Multidrug Resistant ◽  
Regulatory Genes ◽  
Control Group ◽  
Rna Expression ◽  
Rna Seq ◽  
Expression Study

BACKGROUND: The mechanism underlying kanamycin (KM) resistance in Mycobacterium tuberculosis is not well understood, although efflux pump proteins are thought to play a role. This study used RNA-seq data to investigate changes in the expression levels of efflux pump genes following exposure to KM.METHODS: RNA expression of efflux pump and regulatory genes following exposure to different concentrations of KM (minimum inhibitory concentration MIC 25 and MIC50) in rrs wild-type strain and rrs A1401G mutated strain were compared with the control group.RESULTS: The selected strains had differential RNA expression patterns. Among the 71 putative efflux pump and regulatory genes, 46 had significant fold changes, and 12 genes (Rv0842, Rv1146, Rv1258c, Rv1473, Rv1686c, Rv1687c, Rv1877, Rv2038c, Rv3065, Rv3197a, Rv3728 and Rv3789) that were overexpressed following exposure to KM were thought to contribute to drug resistance. Rv3197A (whiB7) showed a distinct fold change based on the concentration of KM.CONCLUSION: The significant changes in the expression of the efflux pump and regulatory genes following exposure to KM may provide insights into the identification of a new resistance mechanism.

Detection of efflux pump genes in multiresistant Acinetobacter baumannii ST2 in Iran

2021 ◽  
Author(s):  
Zahra Meshkat ◽  
Himen Salimizand ◽  
Yousef Amini ◽  
Davood Mansury ◽  
Abolfazl Rafati Zomorodi ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Genes ◽  
Efflux Pump ◽  
Tetracycline Resistance ◽  
Genomic Diversity ◽  
Expression Level ◽  
Tetracycline Resistance Genes ◽  
Microdilution Method ◽  
Relationship Of ◽  
Repetitive Extragenic Palindromic Pcr

AbstractAcinetobacter baumannii, as a nosocomial pathogen has become a worldwide concern in recent years. In the current study, the resistance to tetracyclines and colistin were assessed in the isolates from different provinces of Iran.During the timeline of this study, a number of 270 isolates of A. baumannii were collected from tracheal aspirates, wounds, urine and blood cultures. The minimum inhibitory concentration (MIC) for tetracycline, doxycycline, minocycline, tigecycline and colistin were evaluated. Tetracycline resistance genes were assessed by PCR. The mean expression level of adeB, adeJ and adeG were assessed using semi quantitative Real-Time PCR. The clonal relationship of the isolates was evaluated by the repetitive extragenic palindromic PCR (REP-PCR), International Clonal (IC) Lineage Multiplex PCR and multilocus sequence typing (MLST) (Pasteur scheme) methods.The MIC by microdilution method showed that 87.5, 51.4, 28, 0.74 and 0% of the isolates were resistant to tetracycline, doxycycline, minocycline, tigecycline and colistin respectively. The prevalence of tetracycline resistance genes was 99.2, 99.2, 98, 86.7, 10, 3.33, 0.37, 0% for adeB, adeJ, adeG, tetB, tetA(39), tetA, tetM and tetH in tetracycline-resistant isolates. Moreover, the expression level of adeB, adeJ, adeG genes in tigecycline-nonsusceptible A. baumannii (TNAB) strain was higher compared to the tigecycline-susceptible A. baumannii (TSAB). A broad genomic diversity was revealed, but ST2 was the most prevalent ST. Our results indicated that tetracycline resistance in Iran is mediated by resistance-nodulation-cell division (RND) and tetB efflux pumps.

scholarly journals CARACTERÍSTICAS DE CULTURAS LÁCTICAS PROBIÓTICAS PARA USO EM PRODUTOS CÁRNEOS FERMENTADOS: SENSIBILIDADE AOS SAIS DE CURA E USO DE ANTIBIÓTICOS PARA CONTAGEM SELETIVA

2005 ◽  
Vol 23 (1) ◽  
Author(s):  
RENATA E. FREITAS DE MACEDO ◽  
SÉRGIO BERTELLI PLANZER JR ◽  
NELCINDO NASCIMENTO TERRA ◽  
RENATO J. SOSSELA FREITAS
Keyword(s):  
Sodium Chloride ◽  
Sodium Nitrite ◽  
Lactobacillus Casei ◽  
Culture Media ◽  
Starter Culture ◽  
Meat Products ◽  
Lactobacillus Paracasei ◽  
Pediococcus Pentosaceus ◽  
Probiotic Strains ◽  
Simultaneous Use

Os objetivos deste trabalho foram avaliar a resistência de espécies probióticas de Lactobacillus na presença de sais de cura e testar sua sensibilidade frente a diferentes antimicrobianos para o desenvolvimento de meio de cultura seletivo. As culturas Lactobacillus casei, Lactobacillus paracasei e Lactobacillus rhamnosus foram semeadas em ágar MRS contendo concentrações de 0% a 3% de cloreto de sódio e 0 a 200 ppm de nitrito de sódio. O efeito do uso concomitante dos sais de cura foi verificado utilizando-se 3% de cloreto de sódio e 200 ppm de nitrito de sódio. As bactérias probióticas e a cultura starter Pediococcus pentosaceus foram testadas frente a 20 discos de antimicrobianos pela técnica de disco-difusão. O crescimento dos probióticos não apresentou alteração nas diferentes concentrações de cloreto de sódio, assim como nas concentrações de até 200 ppm de nitrito de sódio. Verificou-se resistência ao uso simultâneo de cloreto e nitrito de sódio. Entre os antimicrobianos testados, a tetraciclina apresentou resultados satisfatórios para a inibição dos probióticos permitindo o crescimento isolado da cultura starter. Os probióticos apresentaram desenvolvimento satisfatório na presença dos sais de cura, demonstrando potencial para sua utilização em produtos cárneos fermentados com ação probiótica. CHARACTERISTICS OF PROBIOTIC CULTURES FOR THE USE IN FERMENTED MEAT PRODUCTS - SENSIBILITY TO CURING SALTS AND ANTIBIOTIC USE FOR THE SELECTIVE ENUMERATION Abstract The objective of this study was to evaluate the resistance of probiotic species of Lactobacillus in the presence of curing salts and to test their sensibility in the presence of antibiotics for the development of a selective culture media. The probiotic cultures, Lactobacillus casei, Lactobacillus paracasei spp paracasei and Lactobacillus casei spp rhamnosus, were plated in MRS agar with concentration of 0 to 3% of sodium chloride and 0 to 200 ppm of sodium nitrite. The inhibitory effect of 3% sodium chloride and 200 ppm sodium nitrite in simultaneous use was evaluated for the probiotic strains. The sensibility of the starter culture, Pediococcus pentosaceus and the probiotic cultures in the presence of antibiotic was carried out using 20 different antibiotic discs by the disc-diffusion technique. The growth of the probiotic cultures wasn’t affected at different concentrations of sodium chloride, and even to concentrations of 200 ppm of sodium nitrate. Resistance was verified by simultaneous use of sodium chloride and nitrate. Among the tested antibiotics, tetracycline showed a satisfactory inhibition effect for the probiotic strains, since the growth of starter Pediococcus pentosaceus was not affected. The probiotics showed satisfactory growth in the presence of curing

scholarly journals Novel Tetracycline Resistance Determinant Isolated from an Environmental Strain of Serratia marcescens

2007 ◽  
Vol 73 (7) ◽  
pp. 2199-2206 ◽  
Author(s):  
Stuart A. Thompson ◽  
Elizabeth V. Maani ◽  
Angela H. Lindell ◽  
Catherine J. King ◽  
J. Vaun McArthur
Keyword(s):  
Serratia Marcescens ◽  
Efflux Pump ◽  
Tetracycline Resistance ◽  
Amino Acid Identity ◽  
Resistance Determinant ◽  
Mercury Resistance ◽  
Resistance Locus ◽  
Environmental Strain ◽  
Apparent Lack ◽  
E Coli

ABSTRACT Resistances to tetracycline and mercury were identified in an environmental strain of Serratia marcescens isolated from a stream highly contaminated with heavy metals. As a step toward addressing the mechanisms of coselection of heavy metal and antibiotic resistances, the tetracycline resistance determinant was cloned in Escherichia coli. Within the cloned 13-kb segment, the tetracycline resistance locus was localized by deletion analysis and transposon mutagenesis. DNA sequence analysis of an 8.0-kb region revealed a novel gene [tetA(41)] that was predicted to encode a tetracycline efflux pump. Phylogenetic analysis showed that the TetA(41) protein was most closely related to the Tet(39) efflux protein of Acinetobacter spp. yet had less than 80% amino acid identity with known tetracycline efflux pumps. Adjacent to the tetA(41) gene was a divergently transcribed gene [tetR(41)] predicted to encode a tetracycline-responsive repressor protein. The tetA(41)-tetR(41) intergenic region contained putative operators for TetR(41) binding. The tetA(41) and tetR(41) promoters were analyzed using lacZ fusions, which showed that the expression of both the tetA(41) and tetR(41) genes exhibited TetR(41)-dependent regulation by subinhibitory concentrations of tetracycline. The apparent lack of plasmids in this S. marcescens strain, as well as the presence of metabolic genes adjacent to the tetracycline resistance locus, suggested that the genes were located on the S. marcescens chromosome and may have been acquired by transduction. The cloned Tet 41 determinant did not confer mercury resistance to E. coli, confirming that Tet 41 is a tetracycline-specific efflux pump rather than a multidrug transporter.

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