Purification and characterization of bacteriocins-like inhibitory substances from food isolated Enterococcus faecalis OS13 with activity against nosocomial enterococci

AbstractNosocomial infections caused by enterococci are an ongoing global threat. Thus, finding therapeutic agents for the treatment of such infections are crucial. Some Enterococcus faecalis strains are able to produce antimicrobial peptides called bacteriocins. We analyzed 65 E. faecalis isolates from 43 food samples and 22 clinical samples in Egypt for 17 common bacteriocin-encoding genes of Enterococcus spp. These genes were absent in 11 isolates that showed antimicrobial activity putatively due to bacteriocins (three from food, including isolate OS13, and eight from clinical isolates). The food-isolated E. faecalis OS13 produced bacteriocin-like inhibitory substances (BLIS) named enterocin OS13, which comprised two peptides (enterocin OS13α OS13β) that inhibited the growth of antibiotic-resistant nosocomial E. faecalis and E. faecium isolates. The molecular weights of enterocin OS13α and OS13β were determined as 8079 Da and 7859 Da, respectively, and both were heat-labile. Enterocin OS13α was sensitive to proteinase K, while enterocin OS13β was resistant. Characterization of E. faecalis OS13 isolate revealed that it belonged to sequence type 116. It was non-hemolytic, bile salt hydrolase-negative, gelatinase-positive, and sensitive to ampicillin, penicillin, vancomycin, erythromycin, kanamycin, and gentamicin. In conclusion, BLIS as enterocin OS13α and OS13β represent antimicrobial agents with activities against antibiotic-resistant enterococcal isolates.

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Prevalence, antibiotic susceptibility and characterization of Vibrio parahaemolyticus isolates in China

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa136 ◽

2020 ◽

Vol 367 (16) ◽

Author(s):

Tengfei Xie ◽

Quan Yu ◽

Xiong Tang ◽

Jing Zhao ◽

Xujun He

Keyword(s):

Vibrio Parahaemolyticus ◽

Antimicrobial Agents ◽

Consensus Sequence ◽

Multidrug Resistant ◽

Food Samples ◽

Retail Markets ◽

Aquatic Product ◽

Resistance Patterns ◽

Maximum Proportion

Abstract Vibrio parahaemolyticus is a marine and estuarine bacterium that poses a major threat to human health worldwide. In this study, from 2017 to 2019, we evaluated 900 food samples collected from China in 2017, with the aim of determining the incidence and features of V. parahaemolyticus in ready-to-eat (RTE) foods, shrimp and fish in China. The contamination rates in these were 3.67, 19.33 and 10.67%, respectively, and the prevalence of V. parahaemolyticus was higher in summer than in winter. In addition, 101 V. parahaemolyticus strains were isolated. Our results suggested that most of the isolates were resistant to aminoglycosides based on the antimicrobial resistance patterns of these aquatic product isolates against 14 antimicrobial agents. Furthermore, most of the isolates were multidrug-resistant. Serotyping showed that the isolates of the O2 serotype comprised the maximum proportion. Enterobacterial repetitive intergenic consensus sequence (ERIC)-PCR results indicated that the isolates (n = 101) could be classified into 12 clusters. There were 82 STs suggesting genetic variation and relatedness among these isolates. Our findings demonstrated the presence of V. parahaemolyticus in foods from Chinese retail markets and show that this methodology can be used for microbiological risk assessment in China.

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Detection of Multiple-Antimicrobial Resistance and Characterization of the Implicated Genes in Escherichia coli Isolates from Foods of Animal Origin in Tunis

Journal of Food Protection ◽

10.4315/0362-028x-72.5.1082 ◽

2009 ◽

Vol 72 (5) ◽

pp. 1082-1088 ◽

Cited By ~ 20

Author(s):

AHLEM JOUINI ◽

KARIM BEN SLAMA ◽

YOLANDA SÁENZ ◽

NAOUEL KLIBI ◽

DANIELA COSTA ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Antimicrobial Agents ◽

Food Samples ◽

Animal Origin ◽

E Coli ◽

Antimicrobial Resistance Genes ◽

Class 1 ◽

Agar Dilution

Phenotypic and genotypic characterization of antimicrobial resistance was conducted for 98 Escherichia coli isolates recovered from 40 food samples of animal origin (poultry, sheep, beef, fish, and others) obtained in supermarkets and local butcheries in Tunis during 2004 and 2005. Susceptibility to 15 antimicrobial agents was tested by disk diffusion and agar dilution methods, the mechanisms of resistance were evaluated using PCR and sequencing methods, and the clonal relationship among isolates was evaluated using pulsed-field gel electrophoresis. High resistance was detected to tetracycline, sulphonamides, nalidixic acid, ampicillin, streptomycin, and trimethoprim-sulfamethoxazole (29 to 43% of isolates), but all isolates were susceptible to cefotaxime, ceftazidime, cefoxitin, azthreonam, and amikacin. One-third of the isolates had multiresistant phenotypes (resistance to at least five different families of antimicrobial agents). Different variants of blaTEM, tet, sul, dfrA, aadA, and aac(3) genes were detected in most of the strains resistant to ampicillin, tetracycline, sulphonamide, trimethoprim, streptomycin, and gentamicin, respectively. The presence of class 1 and class 2 integrons was studied in 15 sulphonamide-resistant unrelated E. coli strains, and 14 of these strains harbored class 1 integrons with five different arrangements of gene cassettes, and a class 2 integron with the dfrA1 + sat + aadA1 arrangement was found in one strain. This study revealed the high diversity of antimicrobial resistance genes, some of them included in integrons, in E. coli isolates of food origin.

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The Synergetic Effect of Sitafloxacin-Arbekacin Combination in the Mycobacteroides abscessus Complex

10.21203/rs.3.rs-767954/v1 ◽

2021 ◽

Author(s):

Junko Watanabe ◽

Hiroaki Ihara ◽

Satomi Takei ◽

Ayako Nakamura ◽

Yuichi Fujimoto ◽

...

Keyword(s):

Antimicrobial Agents ◽

Synergistic Effects ◽

Synergetic Effect ◽

University Hospital ◽

New Combination ◽

Clinical Samples ◽

Rapid Progression ◽

Combination Regimen ◽

Antibiotic Resistant ◽

Genus Mycobacterium

Abstract Background Mycobacteroides abscessus (M. abscessus) is the most commonly isolated rapidly growing mycobacteria (RGM) and is one of the most antibiotic-resistant RGM with rapid progression, therefore, treatment of M. abscessus is still challenging. The genus mycobacterium has long been known to have both rough and smooth colony phenotypes. Rough morphotypes generally are more virulent than smooth morphotypes. Recently, the efficacy of sitafloxacin, new fluoroquinolone (FQ), containing regimens against M. abscessus complex have been reported. We here presented a new combination treatment with sitafloxacin that targeted rough morphotypes of M. abscessus, causing aggressive infections. Results Thirty-four clinical strains of M. abscessus were isolated from various clinical samples at the Juntendo university hospital from 2011 to 2020. The susceptibility to a combination of sitafloxacin and antimicrobial agents was compared to that of the antimicrobial agents alone. Ten isolates (90.9%) of M. abscessus subsp. abscessus were susceptible to both sitafloxacin and arbekacin when the combination is administered; while, 11 isolates (50.0%) of M. abscessus subsp. massiliense were susceptible. Synergistic effects against M. abscessus complex were shown in 8 strains (23.5%) treated with sitafloxacin-amikacin combination, 9 (26.5%) and 19 (55.9%) of sitafloxacin-imipenem combination, and sitafloxacin-arbekacin combination, respectively. Sitafloxacin-arbekacin combination also exhibited synergistic effects against 10 strains (45.5%) of M. abscessus subsp. massiliense and 8 stains (72.7%) of M. abscessus subsp. abscessus, a highly resistant subspecies of M. abscessus. The sitafloxacin-arbekacin combination revealed more synergistic effects in rough morphotypes of M. abscessus complex (p = 0.008). Conclusion We demonstrated the synergistic effect of the sitafloxacin-arbekacin combination against M. abscessus complex. Further, this combination regimen might be more effective against M. abscessus subsp. abscessus or rough morphotypes of M. abscessus complex.

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Production and Extraction Of Antibacterial Bacteriocin from Pediococcus sp. NWD 015

Indonesian Journal of Biotechnology ◽

10.22146/ijbiotech.7566 ◽

2015 ◽

Vol 11 (2) ◽

Author(s):

N. Nofisulastri ◽

Zaenal Bachruddin ◽

Eni Harmayani

Keyword(s):

Heat Treatment ◽

Molecular Weight ◽

Staphylococcus Aureus ◽

Listeria Monocytogenes ◽

Enterococcus Faecalis ◽

Storage Time ◽

Bacteriocin Production ◽

Proteinase K ◽

Bacteriocin Activity

objectives were to study the growth pattern of Pediococcus sp. NWD 015 and bacteriocin activity, extractionand characterization of bacteriocin, and to determine the effect of storage time and temperature on bacteriocinactivity. Results showed that the bacteriocin activity increased during growth and reached the highest activity duringstationary phase. The maximum bacteriocin production reached after incubation of the cell for 12 h at 37oC in TGEbroth and decreased after 96 h incubation. Extraction with adsorbtion-desorbtion method could increased a specificactivity of bacteriocin. Bacteriocin from Pediococcus sp. NWD 015 is inactivated by Proteinase-K; however it is stillactive by heat treatment at 121oC for 15 min and over pH 2 – 11. Bacteriocin of Pediococcus sp. NWD 015 was effectiveagaints Enterococcus faecalis, Staphylococcus aureus, Eschericia coli, Listeria monocytogenes but not against Salmonellathypimurium. The molecular weight of bacteriocin is 4.95 kDa.Keywords : Bacteriocins, Pediococcus sp NWD 015.

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A Study of Isolation and Identification of Multidrug Resistant Pseudomonas aeruginosa from Wound Specimen

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2020/v32i3230930 ◽

2020 ◽

pp. 26-31

Author(s):

Maria Muddassir ◽

Sadaf Munir ◽

Almas Raza ◽

Adeel Iqbal ◽

Muddassir Ahmed ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Multidrug Resistance ◽

Antimicrobial Agents ◽

Morphological Characteristics ◽

Multidrug Resistant ◽

Hospitalized Patients ◽

Clinical Samples ◽

Isolation And Identification ◽

Antimicrobial Drugs ◽

Antibiotic Resistant

Background: Pseudomonas aeruginosa is a clinically important pathogenic microbe in hospitalized patients. It is a major cause of mortality and morbidity having a number of mechanisms that make it antibiotic resistant. Considering the dearth of antimicrobial drugs to treat infection with this pathogen, it has become a necessity to open up new arena for treatment with this organism. Recently, there has been an up rise in the number of multidrug resistant pathogenic strains of Pseudomonas aeruginosa. Objective: Isolation and identification of multidrug resistant Pseudomonas aeruginosa from wound specimens and to evaluate the antibiotic resistant strains of this microbe. Methodology: One hundred and fifty clinical samples of wound were taken from hospitalized patients at Jinnah hospital Lahore during the period of October 2019 to April 2020. In total, twenty (20) isolates of Pseudomonas aeruginosa were identified using the cultural features, morphological characteristics and various biochemical tests plus the Vitek 2 system. Blue/green, brown /blue and yellow/green pigment production showed the presence and growth of Pseudomonas aeruginosa. Results: Percentage of Pseudomonas aeruginosa in females came out to be 15% as compared to 11.42% in males. This was followed by testing susceptibility of isolates of Pseudomonas aeruginosa to various antimicrobial drugs. Piperacillin/tazobactam and meropenem showed the highest efficacy against Pseudomonas aeruginosa. Highest resistance was exhibited against trimethoprim/sulfamethoxazole which was 75%. Conclusion: Most isolates showed multidrug resistance to four or more drugs. Development of multidrug resistance has emerged as a global problem with pathogens commonly causing infections becoming increasingly resistant to antimicrobial agents.

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Isolation and Genetic Characterization of Vancomycin-resistant and mecC+ Methicillin-resistant Staphylococcus aureus Strains in Clinical Samples of Bojnurd, Northeastern Iran

Jundishapur Journal of Microbiology ◽

10.5812/jjm.118949 ◽

2021 ◽

Vol 14 (10) ◽

Author(s):

Parastoo Zarghami Moghaddam ◽

Amir Azimian ◽

Abbas Akhavan Sepahy ◽

Alireza Iranbakhsh

Keyword(s):

Staphylococcus Aureus ◽

Tertiary Hospital ◽

Clinical Samples ◽

Spa Typing ◽

Antibiotic Resistant ◽

Methicillin Resistant ◽

Alpha Hemolysin ◽

Pcr Method ◽

Vancomycin Resistant

Background: The emergence of antibiotic-resistant Staphylococcus aureus strains is one of the major concerns about the various staphylococcal infections. Vancomycin is one the most important effective antibiotics on staphylococcal lethal infections. To date, vancomycin-resistant strains are increasingly isolated in different parts of the world, and it is alerting. Objectives: The current study was designed to evaluate the prevalence, and antibiotic susceptibility pattern of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) isolates in the main tertiary hospital of Bojnurd, Iran. Methods: S. aureus isolates were collected from different clinical samples in Imam Reza Hospital of Bojnurd. After identification of isolates through using conventional methods, they were evaluated by agar screening, disk diffusion, and minimum inhibitory concentration (MIC) methods to determine resistance to vancomycin and methicillin. We also performed polymerase chain reaction (PCR) for the detection of mecA, mecC, vanA, and vanB genes. After confirmation of vancomycin resistance, genetic analysis was performed using SCCmec, agr, and spa typing, and multilocus sequence typing (MLST) methods on VRSA isolates. Results: We found four vancomycin-resistant isolates (1.29%). Also, 75% of isolates were resistant to cefoxitin. Using the PCR method, mecA was found in 73%, mecC in 0.64%, and vanA in 1.29% of isolates. Interestingly, we found two mecC positive isolates in MRSA isolates. The alpha-hemolysin (81.81%) and enterotoxin C (27%) had the highest and lowest toxins percentage, respectively. Among mecA positive isolates, SCCmecIV (37%), SCCmecIII (31.27%), SCCmecI (14%), SCCmecII (11%), and SCCmecV (5.7%) were the most prevalent SCCmec types, respectively. It should be noted that the two mecC positive isolates belonged to SCCmecXI. AgrI (76.29%) was the highest agr type. We recognized t037 as the dominant spa type, and ST239, ST6, ST97, and ST8 were found in VRSA isolates. Conclusions: In our study, the frequency of mecA genes in MRSA isolates was very high. It seems that the resistant isolates belonged to endemic clones of Iran.

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Detection of Salmonella spp. in Retail Raw Food Samples from Vietnam and Characterization of Their Antibiotic Resistance

Applied and Environmental Microbiology ◽

10.1128/aem.00972-07 ◽

2007 ◽

Vol 73 (21) ◽

pp. 6885-6890 ◽

Cited By ~ 84

Author(s):

Thi Thu Hao Van ◽

George Moutafis ◽

Taghrid Istivan ◽

Linh Thuoc Tran ◽

Peter J. Coloe

Keyword(s):

Antibiotic Resistance ◽

Nalidixic Acid ◽

Gene Cluster ◽

Resistance Gene ◽

Antimicrobial Agents ◽

Genomic Island ◽

Antibiotic Resistance Gene ◽

Food Samples ◽

Salmonella Spp

ABSTRACT A study was conducted to examine the levels of Salmonella spp. contamination in raw food samples, including chicken, beef, pork, and shellfish, from Vietnam and to determine their antibiotic resistance characteristics. A total of 180 samples were collected and examined for the presence of Salmonella spp., yielding 91 Salmonella isolates. Sixty-one percent of meat and 18% of shellfish samples were contaminated with Salmonella spp. Susceptibility of all isolates to a variety of antimicrobial agents was tested, and resistance to tetracycline, ampicillin/amoxicillin, nalidixic acid, sulfafurazole, and streptomycin was found in 40.7%, 22.0%, 18.7%, 16.5%, and 14.3% of the isolates, respectively. Resistance to enrofloxacin, trimethoprim, chloramphenicol, kanamycin, and gentamicin was also detected (8.8 to 2.2%). About half (50.5%) of the isolates were resistant to at least one antibiotic, and multiresistant Salmonella isolates, resistant to at least three different classes of antibiotics, were isolated from all food types. One isolate from chicken (serovar Albany) contained a variant of the Salmonella genomic island 1 antibiotic resistance gene cluster. The results show that antibiotic resistance in Salmonella spp. in raw food samples from Vietnam is significant.

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Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates from Egyptian Patients

10.21203/rs.3.rs-123397/v1 ◽

2020 ◽

Author(s):

Reem M Hassan ◽

Sherifa T Salem ◽

Saly Ismail Mostafa Hassan ◽

Asmaa Hegab ◽

Yasmine S Elkholy

Keyword(s):

Acinetobacter Baumannii ◽

Molecular Characterization ◽

Antimicrobial Agents ◽

Treatment Options ◽

Carbapenem Resistance ◽

Common Mechanism ◽

Carbapenem Resistant ◽

Egyptian Patients ◽

Global Threat

Abstract Acinetobacter baumannii (A. baumannii) represents a global threat owing to its ability to resist most of the currently available antimicrobial agents. Moreover, emergence of carbapenem resistant A. baumannii (CR-AB) isolates limits the available treatment options. Enzymatic degradation by variety of ß-lactamases, have been identified as the most common mechanism of carbapenem resistance in A. baumannii. The alarming increase in the prevalence of CR-AB necessitates continuous screening and molecular characterization to appreciate the problem. The present study was performed to assess the prevalence and characterize carbapenemases among 206 CR-AB isolated from various clinical specimens collected from different intensive care units at Kasr Al-Aini Hospital. All isolates were confirmed to be A. baumannii by detection of the blaOXA-51-like gene. Molecular screening of 13 common Ambler class bla carbapenemases genes in addition to insertion sequence (IS-1) upstream OXA-23 was performed by using four sets of multiplex PCR, followed by identification using gene sequencing technology. Among the investigated genes, the prevalence of blaOXA-23, and blaOXA-58 were 77.7%, and 1.9%, respectively. The ISAba1 was detected in 10% of the blaOXA-23 positive isolates. The prevalence of metallo-β-lactamases (MBLs) studied; blaNDM-1, blaSPM, blaVIM, blaSIM-1 were 11.7%, 6.3%, 0.5%, and 0.5% respectively. One of class A; bla KPC was detected in 10.7% of the investigated isolates. blaOXA-24/40, blaIMP, blaGES, blaVEB and blaGIM were not detected in any of the studied isolates. Moreover, 18.4% of the isolates have shown to harbor two or more of the screened bla genes. We concluded that the most prevalent type of ß-lactamases genes among CR-AB isolates collected from Egyptian patients were blaOXA-23 followed by blaNDM-1 and blaKPC.

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Characterization of the Ends and Target Site of a Novel Tetracycline Resistance-Encoding Conjugative Transposon from Enterococcus faecium 664.1H1

Journal of Bacteriology ◽

10.1128/jb.00129-06 ◽

2006 ◽

Vol 188 (12) ◽

pp. 4356-4361 ◽

Cited By ~ 17

Author(s):

Adam P. Roberts ◽

Ian J. Davis ◽

Lorna Seville ◽

Aurelie Villedieu ◽

Peter Mullany

Keyword(s):

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Tetracycline Resistance ◽

Direct Repeat ◽

Target Site ◽

Specific Site ◽

Pathogenicity Islands ◽

Conjugative Transposon ◽

Antibiotic Resistant

ABSTRACT Enterococcus faecium 664.1H1 is multiply antibiotic resistant and mercury resistant. In this study, the genetic support for the tetracycline resistance of E. faecium 664.1H1 was characterized. The tet(S) gene is responsible for tetracycline resistance, and this gene is located on the chromosome of E. faecium 664.1H1, on a novel conjugative transposon. The element is transferable to Enterococcus faecalis, where it integrates into a specific site. The element was designated EfcTn1. The integrase of EfcTn1 is related to the integrase proteins found on staphylococcal pathogenicity islands. We show that the transposon is flanked by an 18-bp direct repeat, a copy of which is also present at the target site and at the joint of a circular form, and we propose a mechanism of insertion and excision.

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