scholarly journals Characteristics of High-Level Aminoglycoside-Resistant Enterococcus faecalis Isolated from Bulk Tank Milk in Korea

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1724
Author(s):  
Hyo Jung Kang ◽  
Sunghyun Yoon ◽  
Koeun Kim ◽  
Young Ju Lee

Enterococci, which are considered environmental mastitis-causing pathogens, have easily acquired aminoglycoside-resistant genes that encode various aminoglycoside-modifying enzymes (AME). Therefore, this study was conducted to compare the distribution of high-level aminoglycoside-resistant (HLAR) and multidrug-resistant (MDR) Enterococcus faecalis (E. faecalis) bacteria isolated from bulk tank milk in four dairy companies in Korea. Moreover, it analyzed the characteristics of their antimicrobial resistance genes and virulence factors. Among the 301 E. faecalis bacteria studied, 185 (61.5%) showed HLAR with no significant differences among the dairy companies. Furthermore, 129 (69.7%) of the 185 HLAR E. faecalis showed MDR without significant differences among companies. In contrast, HLAR E. faecalis from companies A, B, and C were significantly higher in resistance to the four classes than those in company D, which had the highest MDR ability against the three antimicrobial classes (p < 0.05). In addition, in the distribution of AME genes, 72 (38.9%) and 36 (19.5%) of the isolates carried both aac(6′)Ie-aph(2″)-la and ant(6)-Ia genes, and the ant (6)-Ia gene alone, respectively, with significant differences among the companies (p < 0.05). In the distribution of virulence genes, the ace (99.5%), efa A (98.9%), and cad 1 (98.4%) genes were significantly prevalent (p < 0.05). Thus, our results support that an advanced management program by companies is required to minimize the dissemination of antimicrobial resistance and virulence factors.

2011 ◽  
Vol 74 (10) ◽  
pp. 1639-1648 ◽  
Author(s):  
CINDY-LOVE TREMBLAY ◽  
ANN LETELLIER ◽  
SYLVAIN QUESSY ◽  
MARTINE BOULIANNE ◽  
DANIELLE DAIGNAULT ◽  
...  

This study was conducted to characterize the antimicrobial resistance determinants and investigate plasmid colocalization of tetracycline and macrolide genes in Enterococcus faecalis and Enterococcus faecium from broiler chicken and turkey flocks in Canada. A total of 387 E. faecalis and E. faecium isolates were recovered from poultry cecal contents from five processing plants. The percentages of resistant E. faecalis and E. faecium isolates, respectively, were 88.1 and 94% to bacitracin, 0 and 0.9% to chloramphenicol, 0.7 and 14.5% to ciprofloxacin, 72.6 and 80.3% to erythromycin, 3.7 and 41% to flavomycin, 9.6 and 4.3% (high-level resistance) to gentamicin, 25.2 and 17.1% (high-level resistance) to kanamycin, 100 and 94% to lincomycin, 0 and 0% to linezolid, 2.6 and 20.5% to nitrofurantoin, 3 and 27.4% to penicillin, 98.5 and 89.7% to quinupristin-dalfopristin, 7 and 12.8% to salinomycin, 46.7 and 38.5% (high-level resistance) to streptomycin, 95.6 and 89.7% to tetracycline, 73 and 75.2% to tylosin, and 0 and 0% to vancomycin. One predominant multidrug-resistant phenotypic pattern was identified in both E. faecalis and E. faecium (bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, tetracycline, and tylosin). These isolates were further examined by PCR and sequencing for the genes encoding their antimicrobial resistance. Various combinations of vatD, vatE, bcrR, bcrA, bcrB, bcrD, ermB, msrC, linB, tetM, and tetO genes were detected, and ermB, tetM, and bcrB were the most common antimicrobial resistance genes identified. For the first time, plasmid extraction and hybridization revealed colocalization of tetO and ermB genes on a ca. 11-kb plasmid in E. faecalis isolates, and filter mating experiments demonstrated its transferability. Results indicate that the intestinal enterococci of healthy poultry, which can contaminate poultry meat at slaughter, could be a reservoir for quinupristin-dalfopristin, bacitracin, tetracycline, and macrolide resistance genes.


2021 ◽  
Author(s):  
Yu Jin Lee ◽  
Koeun Kim ◽  
Young Ju Lee

Abstract Background: Enterococci are environmental pathogens that can cause bovine mastitis and macrolides are widely used for the treatment of bovine mastitis caused by staphylococci and streptococci/enterococci. The aim of this study was performed to compare the phenotypic and genotypic characteristics of high-level erythromycin-resistant (HLER) Enterococcus faecalis (E. faecalis) collected from bulk tank milk of four dairy companies (A, B, C, and D) in Korea. Results: Although isolates from company D showed the highest prevalence of E. faecalis, the prevalence of HLER E. faecalis in company A (73.1%) and C (57.0%) was significantly higher than company D (33.9%) (P < 0.05). A total of 149 HLER E. faecalis isolates showed high rates of resistance to tetracycline (93.3%), followed by doxycycline (70.0%), and chloramphenicol (48.3%). In the distribution of macrolides resistance genes, 147 (98.7%) isolates carried ermB gene alone, and two isolates carried both ermA and ermB genes. No isolates carried ermC, msrA, msrC, or mef genes. In the distribution of other resistance genes, 72 (48.3%) and 60 (40.3%) isolates carried both tetM and tetL genes, and tetM gene alone, respectively, and 38 (25.5%) isolates carried optrA gene. For aminoglycosides resistance genes, the prevalence of both aac(6′)Ie-aph(2″)-la and ant(6′)-Ia genes (43.0%) was the highest. Moreover, 104 (70.0%) isolates harbored Int-Tn gene carrying the Tn916/1545-like transposon. Although the distribution of ermB gene showed no significant difference between the dairy companies, the prevalence of other resistance genes and transposons showed a significant difference between the dairy companies (P < 0.05). Virulence genes, such as ace (99.3%), cad1 and efaA (each 98.7%), and gelE (83.9%), were also highly conserved in the 149 HLER E. faecalis isolates. Conclusions: Our results indicated that HLER E. faecalis isolates from bulk tank milk showed significant differences in phenotypic and genotypic characteristics between the dairy companies. In addition, the prevalence of resistance genes and virulence factors was also high in HLER E. faecalis isolates.


Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 661
Author(s):  
Sunghyun Yoon ◽  
Young Ju Lee

Enterococci are considered to be environmental mastitis-causing pathogens that can easily spread antimicrobial resistance or virulence genes via horizontal transfer. In this study, the molecular characteristics of enterococci from bulk tank milk were investigated to assess the importance of dairy herd management. A total of 338 enterococci (305 Enterococcus faecalis and 33 Enterococcus faecium) were isolated from 1584 batches of bulk tank milk samples from 396 farms affiliated with four dairy companies in Korea, and significant differences (40.6–79.7%) (p < 0.05) in the prevalence of enterococci were observed in the samples from different companies. Enterococci showed the highest resistance to tetracycline (TET) (73.4%), followed by doxycycline (DOX) (49.7%) and erythromycin (ERY) (46.2%), while two enterococci isolates showed resistance to vancomycin (VAN). Among 146 tetracycline (TET) and ERY-resistant enterococci, each 50 (19.4%) enterococci carried combination-resistance and transposon gene types erm(B) + tet(M) + IntTn and erm(B) + tet(L) + tet(M) + IntTn, respectively. The virulence genes such as ace (99.0%), efaA (97.7%), cad1 (95.7%), and gelE (85.9%) were highly conserved in E. faecalis and significantly predominated over E. faecium (p < 0.001). Our results indicate that pathogens from bulk tank milk can also become a reservoir for the dissemination of antimicrobial resistance and virulence factors through cross-contamination processes.


AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Quan Li ◽  
Jian Yin ◽  
Zheng Li ◽  
Zewei Li ◽  
Yuanzhao Du ◽  
...  

AbstractSalmonella is an important food-borne pathogen associated with public health and high economic losses. To investigate the prevalence and the characteristics of Salmonella in a pig slaughterhouse in Yangzhou, a total of 80 Salmonella isolates were isolated from 459 (17.43%) samples in 2016–2017. S. Derby (35/80, 43.75%) was the most prevalent, followed by S. Rissen (16/80, 20.00%) and S. Newlands (11/80, 13.75%). The highest rates of susceptibility were observed to cefoxitin (80/80, 100.0%) and amikacin (80/80, 100.0%), followed by aztreonam (79/80, 98.75%) and nitrofurantoin (79/80, 98.75%). The highest resistance rate was detected for tetracycline (65/80, 81.25%), followed by ampicillin (60/80, 75.00%), bactrim (55/80, 68.75%), and sulfisoxazole (54/80, 67.50%). Overall, 91.25% (73/80) of the isolates were resistant to at least one antibiotic, while 71.25% (57/80) of the isolate strains were multidrug resistant in the antimicrobial susceptibility tested. In addition, 86.36% (19/22) of the 22 antimicrobial resistance genes in the isolates were identified. Our data indicated that the resistance to certain antimicrobials was significantly associated, in part, with antimicrobial resistance genes. Furthermore, 81.25% (65/80) isolates harbored the virulence gene of mogA, of which 2 Salmonella Typhimurium isolates carried the mogA, spvB and spvC virulence genes at the same time. The results showed that swine products in the slaughterhouse were contaminated with multidrug resistant Salmonella commonly, especially some isolates carry the spv virulence genes. The virulence genes might facilitate the dissemination of the resistance genes to consumers along the production chain, suggesting the importance of controlling Salmonella during slaughter for public health.


2008 ◽  
Vol 71 (4) ◽  
pp. 760-769 ◽  
Author(s):  
LORI L. McGOWAN-SPICER ◽  
PAULA J. FEDORKA-CRAY ◽  
JONATHAN G. FRYE ◽  
RICHARD J. MEINERSMANN ◽  
JOHN B. BARRETT ◽  
...  

Although enterococci are considered opportunistic nosocomial pathogens, their contribution to foodborne illnesses via dissemination through retail food remains undefined. In this study, prevalence and association of antimicrobial resistance and virulence factors of 80 Enterococcus faecalis isolates from retail food items were investigated. The highest rates of resistance were observed for lincomycin (73 of 80 isolates, 91%) and bacitracin (57 of 80 isolates, 71%), and lower rates of resistance (≤40%) were found for chloramphenicol, ciprofloxacin, erythromycin, flavomycin, gentamicin, kanamycin, nitrofurantoin, penicillin, and tylosin. Overall resistance to antimicrobials was low for most isolates tested. Of the virulence factors tested, the majority of isolates were positive for ccf (78 of 80 isolates, 98%), efaAfs (77 of 80, 96%), and cpd (74 of 80, 93%). Isolates also commonly contained cob (72 of 80 isolates, 90%) and gelE (68 of 80, 85%). Very few isolates contained cylMBA (12 of 80 isolates [15%] for cylM and 9 of 80 isolates [11%] for both cylB and cylA) and efaAfm (2 of 80 isolates, 3%). Positive statistical associations (significance level of 0.05) were found between agg and tetracycline resistance, cylM and erythromycin resistance, and gelE and efaAfs and lincomycin resistance. The presence of the cylB and cylA alleles also was positively correlated with bacitracin and tetracycline resistance. Negative correlations were observed between many of the virulence attributes and resistance to ciprofloxacin, erythromycin, flavomycin, gentamicin, kanamycin, and tylosin. These data suggest that both positive and negative associations exist between antimicrobial resistance genes and virulence factors in E. faecalis isolates from foods commonly purchased from grocery stores.


2021 ◽  
Author(s):  
Hye-Ri Jung ◽  
Young Ju Lee

Abstract Background: Staphylococcus aureus, a persistent and chronic mastitis-causing pathogen, produces various virulence factors, including enterotoxins. This study analyzed the genetic characteristics of bovine mastitis-related virulence factors to evaluate potential pathogenesis in S. aureus isolated from bulk tank milk.Results: Among 93 S. aureus isolates from 396 dairy farms in six factories operated by three dairy companies in Korea, 40 (43.0%) isolates carried at least one or more enterotoxin genes and there were significant differences between factories within the same company (p < 0.05). Moreover, S. aureus carrying enterotoxin genes showed a higher prevalence in all virulence genes tested in this study except for pvl and lukM, which were not detected in any isolate, than the isolates without enterotoxin genes. In particular, the prevalence of six genes (hla, hlb, lukED, fnbA, clfA, and clfB) was significantly higher in S. aureus carrying enterotoxin genes than isolates without enterotoxin genes (p < 0.05). The most common multilocus sequence type (ST) of 40 enterotoxin-producing isolates was ST188, and all isolates of ST188 harbored the see gene. However, none of the isolates of ST1 and ST72 carried the see gene, and all isolates of ST1 carried the seh gene.Conclusions: Although S. aureus isolated from bulk tank milk, not from mastitis, had a high prevalence of enterotoxins and virulence factors simultaneously, posing a public health threat. Moreover, high enterotoxins in bulk tank milk may be reflected by poor hygiene; therefore, it is important to develop strong monitoring and sanitation programs to ensure that dairy factories produce hygienic milk.


2007 ◽  
Vol 53 (3) ◽  
pp. 372-379 ◽  
Author(s):  
N. Klibi ◽  
K. Ben Slama ◽  
Y. Sáenz ◽  
A. Masmoudi ◽  
S. Zanetti ◽  
...  

Phenotypic and genotypic determination of virulence factors were carried out in 46 high-level gentamicin-resistant (HLGR) clinical Enterococcus faecalis (n = 34) and Enterococcus faecium (n = 12) isolates recovered from different patients in La Rabta Hospital in Tunis, Tunisia, between 2000 and 2003 (all these isolates harboured the aac(6′)–aph(2″) gene). The genes encoding virulence factors (agg, gelE, ace, cylLLS, esp, cpd, and fsrB) were analysed by PCR and sequencing. The production of gelatinase and hemolysin, the adherence to caco-2 and hep-2 cells, and the capacity for biofilm formation were investigated in all 46 HLGR enterococci. The percentages of E. faecalis isolates harbouring virulence genes were as follows: gelE, cpd, and ace (100%); fsrB (62%); agg (56%); cylLLS (41.2%); and esp (26.5%). The only virulence gene detected among the 12 HLGR E. faecium isolates was esp (58%). Gelatinase activity was detected in 22 of the 34 E. faecalis isolates (65%, most of them with the gelE+–fsrB+ genotype); the remaining 12 isolates were gelatinase-negative (with the gelE+–fsrB– genotype and the deletion of a 23.9 kb fragment of the fsr locus). Overall, 64% of the cylLLS-containing E. faecalis isolates showed β-hemolysis. A high proportion of our HLGR E. faecalis isolates, in contrast to E. faecium, showed moderate or strong biofilm formation or adherence to caco-2 and hep-2 cells.


2021 ◽  
Vol 12 ◽  
Author(s):  
Mohammed Elbediwi ◽  
Yanting Tang ◽  
Dawei Shi ◽  
Hazem Ramadan ◽  
Yaohui Xu ◽  
...  

Salmonella spp. is recognized as an important zoonotic pathogen. The emergence of antimicrobial resistance in Salmonella enterica poses a great public health concern worldwide. While the knowledge on the incidence and the characterization of different S. enterica serovars causing chick embryo death remains obscure in China. In this study, we obtained 45 S. enterica isolates from 2,139 dead chick embryo samples collected from 28 breeding chicken hatcheries in Henan province. The antimicrobial susceptibility assay was performed by the broth microdilution method and the results showed that 31/45 (68.8%) isolates were multidrug-resistant (≥3 antimicrobial classes). Besides the highest resistance rate was observed in the aminoglycoside class, all the isolates were susceptible to chloramphenicol, azithromycin, and imipenem. Furthermore, genomic characterization revealed that S. Enteritidis (33.33%; 15/45) was a frequent serovar that harbored a higher number of virulence factors compared to other serovars. Importantly, genes encoding β-lactamases were identified in three serovars (Thompson, Enteritidis, and Kottbus), whereas plasmid-mediated quinolone resistance genes (qnrB4) were detected in certain isolates of S. Thompson and the two S. Kottbus isolates. All the examined isolates harbored the typical virulence factors from Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Additionally, a correlation analysis between the antimicrobial resistance genes, phenotype, and plasmids was conducted among Salmonella isolates. It showed strong positive correlations (r &lt; 0.6) between the different antimicrobial-resistant genes belonging to certain antimicrobial classes. Besides, IncF plasmid showed a strong negative correlation (r &gt; −0.6) with IncHI2 and IncHI2A plasmids. Together, our study demonstrated antimicrobial-resistant S. enterica circulating in breeding chicken hatcheries in Henan province, highlighting the advanced approach, by using genomic characterization and statistical analysis, in conducting the routine monitoring of the emerging antimicrobial-resistant pathogens. Our findings also proposed that the day-old breeder chicks trading could be one of the potential pathways for the dissemination of multidrug-resistant S. enterica serovars.


Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1057
Author(s):  
Jaclyn G. McCutcheon ◽  
Jonathan J. Dennis

The isolation and characterization of bacteriophages for the treatment of infections caused by the multidrug resistant pathogen Stenotrophomonas maltophilia is imperative as nosocomial and community-acquired infections are rapidly increasing in prevalence. This increase is largely due to the numerous virulence factors and antimicrobial resistance genes encoded by this bacterium. Research on S. maltophilia phages to date has focused on the isolation and in vitro characterization of novel phages, often including genomic characterization, from the environment or by induction from bacterial strains. This review summarizes the clinical significance, virulence factors, and antimicrobial resistance mechanisms of S. maltophilia, as well as all phages isolated and characterized to date and strategies for their use. We further address the limited in vivo phage therapy studies conducted against this bacterium and discuss the future research needed to spearhead phages as an alternative treatment option against multidrug resistant S. maltophilia.


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