Characterization of bacteria and antibiotic resistance in commercially-produced cheeses sold in China

2021 ◽  
Author(s):  
Jinghui Yao ◽  
Jing Gao ◽  
Jianming Guo ◽  
Hengan Wang ◽  
En Zhang ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acquired Resistance ◽  
Antibiotic Resistance Genes ◽  
16S Rrna Gene Sequencing ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Rrna Gene ◽  
Rrna Gene Sequencing

The consumption of cheese in China is increasing rapidly. Little is known about the microbiota, the presence of antibiotic-resistant bacteria, or the distribution of antibiotic resistance genes (ARGs) in commercially-produced cheeses sold in China. These are important criteria for evaluating quality and safety. Thus, this study assessed the metagenomics of fifteen types of cheese using 16S rRNA gene sequencing. Fourteen bacterial genera were detected. Lactococcus , Lactobacillus , and Streptococcus were dominant based on numbers of sequence reads. Multidrug-resistant lactic acid bacteria were isolated from most of the types of cheese. The isolates showed 100% and 91.7% resistance to streptomycin and sulfamethoxazole, respectively, and genes involved in acquired resistance to streptomycin ( strB) and sulfonamides ( sul2) were detected with high frequency. To analyze the distribution of ARGs in the cheeses in overall, 309 ARGs from eight categories of ARG and nine transposase genes were profiled. A total of 169 ARGs were detected in the 15 cheeses; their occurrence and abundance varied significantly between cheeses. Our study demonstrates that there is various diversity of the bacteria and ARGs in cheeses sold in China. The risks associated with multidrug resistance of dominant lactic acid bacteria are of great concern.

scholarly journals Distribution and antimicrobial activity of lactic acid bacteria associated with lychee fruits

2020 ◽  
Vol 25 (6) ◽  
pp. 2079-2085
Author(s):  
LIN-HU NAN ◽  
◽  
YI-SHENG CHEN ◽  
HUI-CHUNG WU ◽  
YU-CHING SU ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Novel Species ◽  
16S Rrna Gene Sequencing ◽  
Mass Spectrometry Analysis ◽  
Rrna Gene ◽  
Spectrometry Analysis ◽  
Gram Positive Bacteria ◽  
Rrna Gene Sequencing

Lychee is a popular fruit in China and southeastern Asia. Although it is very popular, the microbiota of lactic acid bacteria (LAB) associated with lychee remains poorly described. Lychee samples from seven different markets located in three cities in Taiwan were collected and a total of 104 LAB were isolated. Through RFLP analyses of 16S rDNA and rpoA genes for grouping and 16S rRNA gene sequencing, these isolates were finally divided into 6 groups (A to F). The most common genera of LAB in lychee samples were Weissella and Leuconostoc. Weissella confusa strain E was found to produce a bacteriocin active against Listeria monocytogenes and some other Gram-positive bacteria. Mass spectrometry analysis revealed the bacteriocin mass to be approximately 3426.77 Da, which is different to other known Weissella bacteriocins. In addition, strain MB7 included in the genus Leuconostoc was identified as potential novel species or subspecies on the basis of phylogenetic analysis of 16S rRNA, rpoA and pheS gene sequences. Thus, this is the first report describing the distribution and varieties of LAB associated with lychee fruits. In addition, one potential novel LAB species or subspecies and one potential novel bacteriocin were also reported in this study.

scholarly journals The Evolution of Multidrug Resistance in an Isolated Pseudomonas Strain

2020 ◽  
Vol 17 (3) ◽  
pp. 41-50
Author(s):  
Allison Grodnick ◽  
Ashley Fink ◽  
Timothy Johnson ◽  
David Mitchell
Keyword(s):  
Multidrug Resistance ◽  
Bacterial Strain ◽  
Acquired Resistance ◽  
16S Rrna Gene Sequencing ◽  
Multidrug Resistant ◽  
Rrna Gene ◽  
Nucleotide Polymorphisms ◽  
Forest Environment ◽  
Antibiotic Drugs ◽  
Rrna Gene Sequencing

As an unintentional result of the extensive use of antibiotics in healthcare and agriculture, antibiotics have become an increasingly prevalent selective pressure on bacteria. This forces bacteria to evolve and acquire antibiotic-resistant genes or mutations in order to survive. Suppose a bacterial strain acquires resistance to three or more antibiotics. In that case, it is deemed multidrug-resistant (MDR), and it becomes a potentially more serious problem to solve in the context of healthcare. This study aims to evaluate the acquisition of resistance to multiple antibiotic drugs by an initially susceptible isolated bacterium from a Minnesota forest environment. The bacterium was found to be Pseudomonas by 16s rRNA gene sequencing. Three antibiotics, neomycin, ciprofloxacin, and imipenem, each from a different drug class, were selected to see if this isolate could become resistant over time and exposure. The bacterial strain developed resistance to the selected antibiotics through a series of sequential exposures to increasing concentrations of each drug in this order. As determined by a disc susceptibility test, the initial isolate acquired resistance to all three selected antibiotics. Single nucleotide polymorphisms (SNPs) between the original isolate and the final resistant strain were identified. These SNPs suggest that mutations to efflux transporters and antibiotic protein targets play a role in acquiring and maintaining antibiotic resistance. KEYWORDS: Multidrug Resistance; Antibiotics; Neomycin; Ciprofloxacin; Imipenem; Pseudomonas; Evolution; MDR; Minnesota Environment

scholarly journals Tracking of Intentionally Inoculated Lactic Acid Bacteria Strains in Yogurt and Probiotic Powder

2019 ◽  
Vol 8 (1) ◽  
pp. 5 ◽  
Author(s):  
Anshul Sharma ◽  
Jasmine Kaur ◽  
Sulhee Lee ◽  
Young-Seo Park
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gene Sequence ◽  
Random Amplified Polymorphic Dna ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Sequence Alignments ◽  
Gene Sequence Analysis ◽  
Rrna Gene Sequencing

The present work aimed at tracking intentionally inoculated lactic acid bacteria (LAB) strains in yogurt and probiotic powder. Leuconostoc (Leu.) mesenteroides (11251), Lactobacillus (L.) brevis (B151), and Lactobacillus plantarum (LB41K) strains were tracked in yogurt, and L. plantarum (LB41P) was tracked in a commercial probiotic powder. The yogurt was intentionally inoculated with the selected bacterial strains. Two types of yogurt with known and unknown bacterial pools were utilized. The standard 16S rRNA gene sequencing was used to evaluate the initial screening. The molecular typing tools, random amplified polymorphic DNA (RAPD), repetitive element palindromic PCR (rep-PCR), and comparative gene sequence analysis of selected housekeeping loci were used to track the inoculated dubious strains. Out of 30 random selections for each inoculation, the developed method identified seven (11251), nine (B151), and five (LB41K) colonies in the yogurt. The validation was performed by identifying 7 colonies (LB41P) out of 30 in the probiotic powder. The DNA banding profiles and the gene sequence alignments led to the identification of the correct inoculated strains. Overall, the study summarizes the use of molecular tools to identify the deliberately inoculated LAB strains. In conclusion, the proposed polyphasic approach effectively tracked the intentionally inoculated strains: Leu. mesenteroides, L. brevis, and L. plantarum (LB41K) in yogurt and L. plantarum (LB41P) in probiotic powder. The study demonstrates how to track industrially relevant misused LAB strains in marketable food products.

scholarly journals Starter cultures of lactic acid bacteria for special diet products

2017 ◽  
Vol 1 (1) ◽  
pp. 89-90 ◽  
Author(s):  
Hanna Aljaksandrauna Bareika ◽  
Anatasija Vyachaslavauna Sidarenka ◽  
Galina Ivanovna Novik
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gene Sequencing ◽  
16S Rrna Gene Sequencing ◽  
Starter Cultures ◽  
Protein Profiling ◽  
Rrna Gene ◽  
Biochemical Characteristics ◽  
Special Diet ◽  
Rrna Gene Sequencing

Abstract From fresh and fermented vegetables (cucumber, sauercraut, eggplant), cereals (wheat, rice), legumes (soy) 37 cultures of lactic acid bacteria were isolated. Based on biochemical characteristics, MALDI-TOF MS protein profiling and 16S rRNA gene sequencing they were identified as representatives of Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Enterococcus genera. Six members of Lactobacillus genera and two members of Leuconostoc genera actively producing EPS were selected for further investigation as components of starters for production of special dietetic foodstuffs.

scholarly journals Biosynthesis and Characterization of Silver Nanoparticles produced by Phormidium ambiguum and Desertifilum tharense

2021 ◽  
Author(s):  
Amira Lotfy Hanna ◽  
Hayam Hamouda ◽  
Hanan Goda ◽  
Tarek Elsayed ◽  
Mahmoud Sadik
Keyword(s):  
Silver Nanoparticles ◽  
Micrococcus Luteus ◽  
16S Rrna Gene Sequencing ◽  
Inhibition Zone ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Rrna Gene ◽  
Face Centered Cubic ◽  
Ag Nps ◽  
Rrna Gene Sequencing

Abstract The world faces a challenge with pervasion of multidrug resistant bacteria which encouraged the scientists to develop and discover alternative ecofriendly and easy to produce new antibacterial agents. Two Egyptian cyanobacteria were isolated and identified according to 16S rRNA gene sequencing as Phormidium ambiguum and Desertifilum tharense . The sequences were deposited in the GenBank with accession numbers of MW762709 and MW762710 for Desertifilum tharense and Phormidium ambiguum, respectively. These isolates have the ability to produce silver nanoparticles (Ag-NPs) extra- and intracellularly under light and dark conditions. The results of UV-Vis analysis showed promising extracellular Ag-NPs synthesis by Desertifilum tharense and Phormidium ambiguum under light conditions. Therefore, these Ag-NPs were characterized and evaluated for antibacterial and antioxidant activity. TEM, SEM and XRD analyses revealed the spherical crystals with face-centered cubic structures and size range of 6.24–11.4 nm and 6.46–12.2 nm for Ag-NPs of Desertifilum tharense and Phormidium ambiguum , respectively. XRD and EDX results clearly confirmed the successful synthesis of Ag-NPs in its oxide form or chloride form. The FTIR spectrum data confirmed the presence of hydroxyl and amide groups. Desertifilum tharense Ag-NPs displayed the largest inhibition zone ranged from 9 mm against Micrococcus luteus ATCC 10240 to 25 mm against methicillin resistant S. aureus (MRSA) ATCC 43300. For Phormidium ambiguum Ag-NPs, the inhibition zone diameter was in a range of 9–18 mm. The Ag-NPs of Phormidium ambiguum exhibited the highest scavenging activity of 48.7% comparing with that of Desertifilum tharense which displayed 43.753%.

scholarly journals Rep PCR Characterization of Lactic Acid Bacteria Isolated From Raw Cows’ Milk in Algeria.

2021 ◽  
Author(s):  
Akil LOMANI ◽  
Dennis S Nielsen ◽  
Larbi Ahmed Amine ◽  
Tahri Ahmed ◽  
Mediani Ahmed
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bile Salts ◽  
Acid Tolerance ◽  
16S Rrna Gene Sequencing ◽  
Fermented Milk ◽  
Haemolytic Activity ◽  
Rrna Gene ◽  
Rrna Gene Sequencing

Abstract Milk and indigenous fermented, milk based products are a rich source of lactic acid bacteria (LAB) and may serve as a source of potential probiotics. In the present study LAB were isolated from raw cows’ milk sampled at five different Algerian farms. A total of 24 Gram positive, catalase negative isolates where identified to species level using a combination of (GTG) 5-based rep-PCR fingerprinting and 16S rRNA gene sequencing. All isolates were identified as Enterococcus faecium and all isolates had highly similar rep-PCR profiles. Four representative isolates were screened for acid tolerance, bile salts tolerance, antimicrobial susceptibility, antibacterial activity and haemolysis. The four selected strains all exhibited good tolerance to low pH (2, 3, and 4), and to bile salts (concentrations of 0.5%, 1%, and 2%) and were sensitive to chloramphenicol, vancomycin, tetracycline, gentamicine and peniciline G, but were resistant to oxaciline. Cell-free supernatants of the four tested strains all inhibited Staphylococcus aureus, Escherichia coli and Listeria monocytogenes but not Salmonella Typhi. No haemolytic activity was observed.

scholarly journals Characterization of Lactic Acid Bacteria in Pecorino di Farindola Cheese and Manufacturing with a Lacticaseibacillus paracasei Autochthonous Culture

2021 ◽  
Vol 11 (17) ◽  
pp. 7897
Author(s):  
Giuseppe Aprea ◽  
Alessandra Alessiani ◽  
Franca Rossi ◽  
Lorena Sacchini ◽  
Arianna Boni ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Escherichia Coli O157 ◽  
Genes Encoding ◽  
Polymerase Chain ◽  
Rrna Gene Sequencing ◽  
Bacterial Groups

This study focused on the characterization of lactic acid bacteria (LAB) in a renowned traditional Italian cheese, Pecorino di Farindola, in order to select an autochthonous culture and investigate its potential for the improvement of safety and functional properties. Two hundred and six LAB isolated throughout production and maturation from nine cheese lots of three farms were identified by 16S rRNA gene sequencing and tested for the presence of genes encoding virulence factors, vancomycin resistance (for enterococci), biogenic amines (BAs) and bacteriocin production for antimicrobial activity; and for the capacity to survive in the gastrointestinal tract (GIT) based on tolerance to low pH and bile salts and adhesion to CaCo-2 cells. A Lacticaseibacillus paracasei isolate was used in cheese making and determined a decline of spiked Listeria monocytogenes and Escherichia coli O157 faster than in the control cheese. The autochthonous bacterial groups were numerically unaffected, apart from lactobacilli that were recovered in higher numbers in cheese with the addition of the L. paracasei strain. Based on repetitive extragenic palyndrome (Rep) polymerase chain reaction (PCR) profiles, the added strain possibly dominated until day 88 in the cheese. Results encourage further trials with autochthonous cultures in order to efficiently inhibit hazardous bacteria and to enrich a functional microbiota in Pecorino di Farindola and similar cheeses.

scholarly journals Characterization of Lactic Acid Bacteria in Pecorino DI Farindola Cheese and Manufacturing with a Lacticaseibacillus Paracasei Autochthonous Culture

2021 ◽  
Author(s):  
Giuseppe Aprea ◽  
Alessandra Alessiani ◽  
Franca Rossi ◽  
Lorena Sacchini ◽  
Arianna Boni ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Intestinal Tract ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Genes Encoding ◽  
Rrna Gene Sequencing ◽  
Gastro Intestinal Tract ◽  
Bacterial Groups

This study focused on the characterization of lactic acid bacteria (LAB) in a renowned traditional Italian cheese, Pecorino di Farindola, to select an autochthonous culture and investigate its po-tential for the improvement of safety and functional properties. Two hundred and six LAB isolated throughout production and maturation from nine cheese lots of three farms were identified by 16S rRNA gene sequencing and tested for the presence of genes encoding virulence factors, vancomycin resistance (for enterococci), biogenic amines (BAs) and bacteriocin production, for antimicrobial activity, and for the capacity to survive in the gastro-intestinal tract (GIT) based on tolerance to low pH and bile salts and adhesion to CaCo-2 cells. A Lacticaseibacillus paracasei isolate was used in cheese making and determined a decline of spiked Listeria monocytogenes and Escherichia coli O157 faster than in control cheese. The autochthonous bacterial groups were numerically unaffected, apart from lactobacilli that were recovered in higher numbers in the cheese with added L. paracasei. Based on Repetitive Extragenic Palyndrome (Rep) PCR profiles, the added strain possibly dominated until day 88 in cheese. Results encourage further trials with autochthonous cultures to efficiently inhibit hazardous bacteria and enrich a functional microbiota in Pecorino di Farindola and similar cheeses.

scholarly journals Characterization of Lactic Acid Bacteria That Have Ability to Improved Number of Carnosine on Bakasang Based on I6S rRNA Gene

2019 ◽  
Vol 4 (1) ◽  
pp. 106-109
Author(s):  
Helen J. Lawalata ◽  
Jovialine A. Rungkat
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Molecular Characterization ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Fermented Fish ◽  
Rrna Gene Sequencing

Diversity of Lactic acid bacteria (LAB) that have ability to improved number of carnocine on bakasang were determind by application of molecular approach. Molecular characterization of LAB was based on 16S rRNA gene sequencing.  The result  showed that one isolate lactic acid bacteria (Pediococcus sp.B.5.1)   among 9 isolates LAB exhibited the highest ability to improved number of carnocine. The molecular characterization based on 16S rRNA gene sequence showed that the Pediococcus B.5.1 isolate  clearly belonged to members of species Pediococcus acidilactici. Therefore, lactic acid bacteria with the high ability to improved number of carnosine could be found from fermented fish bakasang and make bakasang as a functional food.

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