scholarly journals Genetic diversity and antimicrobial resistance of enterococcal isolates from Southern region of Brazil

2006 ◽  
Vol 48 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Pedro Alves d'Azevedo ◽  
Cícero Armídio Gomes Dias ◽  
Lúcia Martins Teixeira
Keyword(s):  
Genetic Diversity ◽  
Antimicrobial Agents ◽  
Acquired Resistance ◽  
Chromosomal Dna ◽  
Pfge Analysis ◽  
Clonal Group ◽  
Group A ◽  
Resistant Strains ◽  
High Level ◽  
The City

In the present study, a total of 455 enterococcal isolates, recovered from patients living in the city of Porto Alegre, State of Rio Grande do Sul, Brazil, during the period from July 1996 to June 1997, were identified to the species level by conventional biochemical and microbiological tests, and assayed for their susceptibilities to antimicrobial agents. The genetic diversity of antimicrobial resistant strains was evaluated by pulsed-field gel electrophoresis (PFGE) analysis of SmaI restricted chromosomal DNA. The most frequent species was Enterococcus faecalis (92.8%). Other species identified were: E. faecium (2.9%), E. gallinarum (1.5%), E. avium (1.1%), E. hirae (0.7%), E. casseliflavus (0.4%), E. durans (0.4%) and E. raffinosus (0.2%). The overall prevalence of isolates with high-level resistance (HLR) to aminoglycosides was 37.8%. HLR to gentamicin was found in 24.8%. No strains with acquired resistance to vancomycin were found. PFGE analysis showed the predominance of clonal group A, comprising strains isolated from different clinical specimens obtained from patients in three hospitals. These results suggest intra and inter-hospital dissemination of one predominant clonal group of E. faecalis isolates with HLR to gentamicin in the hospitals included in this study.

scholarly journals Genotyping and antimicrobial resistance in Escherichia coli from pig carcasses

2017 ◽  
Vol 37 (11) ◽  
pp. 1253-1260 ◽  
Author(s):  
Caroline Pissetti ◽  
Gabriela Orosco Werlang ◽  
Jalusa Deon Kich ◽  
Marisa Cardoso
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Commensal Bacteria ◽  
Pfge Analysis ◽  
Gene Detection ◽  
E Coli ◽  
Antimicrobial Resistance Profile ◽  
Resistant Strains ◽  
Pig Carcasses

ABSTRACT: The increasing antimicrobial resistance observed worldwide in bacteria isolated from human and animals is a matter of extreme concern and has led to the monitoring of antimicrobial resistance in pathogenic and commensal bacteria. The aim of this study was to evaluate the antimicrobial resistance profile of Escherichia coli isolated from pig carcasses and to assess the occurrence of relevant resistance genes. A total of 319 E. coli isolates were tested for antimicrobial susceptibility against different antimicrobial agents. Moreover, the presence of extended-spectrum β-lactamase (ESBL) and inducible ampC-β-lactamase producers was investigated. Eighteen multi-resistant strains were chosen for resistance gene detection and PFGE characterization. The study showed that resistance to antimicrobials is widespread in E. coli isolated from pig carcasses, since 86.2% of the strains were resistant to at least one antimicrobial and 71.5% displayed multi-resistance profiles. No ampC-producing isolates were detected and only one ESBL-producing E. coli was identified. Genes strA (n=15), floR (n=14), aac(3)IVa (n=13), tetB (n=13), sul2 (n=12), tetA (n=11), aph(3)Ia (n=8) and sul3 (n=5) were detected by PCR. PFGE analysis of these multi-resistant E. coli strains showed less than 80% similarity among them. We conclude that antimicrobial multi-resistant E. coli strains are common on pig carcasses and present highly diverse genotypes and resistance phenotypes and genotypes.

scholarly journals Role of embB in natural and acquired resistance to ethambutol in mycobacteria.

1997 ◽  
Vol 41 (10) ◽  
pp. 2270-2273 ◽  
Author(s):  
F Alcaide ◽  
G E Pfyffer ◽  
A Telenti
Keyword(s):  
Nontuberculous Mycobacteria ◽  
Practical Implication ◽  
Acquired Resistance ◽  
Fold Increase ◽  
Drug Susceptibility ◽  
Natural Resistance ◽  
Intrinsic Resistance ◽  
Resistant Strains ◽  
High Level

The mycobacterial embCAB operon encodes arabinosyl transferases, putative targets of the antimycobacterial agent ethambutol (EMB). Mutations in embB lead to resistance to EMB in Mycobacterium tuberculosis. The basis for natural, intrinsic resistance to EMB in nontuberculous mycobacteria (NTM) is not known; neither is the practical implication of resistance to EMB in the absence of embB mutations in M. tuberculosis well understood. The conserved embB resistance-determining region (ERDR) of a collection of 13 strains of NTM and 12 EMB-resistant strains of M. tuberculosis was investigated. Genotypes were correlated with drug susceptibility phenotypes. High-level natural resistance to EMB (MIC, . or =64 microg/ml) was associated with a variant amino acid motif in the ERDR of M. abscessus, M. chelonae, and M. leprae. Transfer of the M. abscessus emb allele to M. smegmatis resulted in a 500-fold increase in the MICs. In M. tuberculosis, embB mutations were associated with MICs of > or =20 microg/ml while resistance not associated with an ERDR mutation generally resulted in MICs of < or =10 microg/ml. These data further support the notion that the emb region determines intrinsic and acquired resistance to EMB and might help in the reassessment of the current recommendations for the screening and treatment of infections with EMB-resistant M. tuberculosis and NTM.

scholarly journals Antimicrobial Resistance of Listeria monocytogenes Strains Isolated from Humans in France

2010 ◽  
Vol 54 (6) ◽  
pp. 2728-2731 ◽  
Author(s):  
A. Morvan ◽  
C. Moubareck ◽  
A. Leclercq ◽  
M. Hervé-Bazin ◽  
S. Bremont ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Antimicrobial Resistance ◽  
Resistant Strain ◽  
Temporal Evolution ◽  
Acquired Resistance ◽  
Mechanisms Of Resistance ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance ◽  
Microbiological Surveillance

ABSTRACT Susceptibility to antibiotics of 4,816 clinical L. monocytogenes strains isolated since 1926 was studied, and the temporal evolution of susceptibility to antibiotics was analyzed through several decades. The mechanisms of resistance in each resistant strain were studied. The prevalence of resistant strains was estimated at 1.27% among isolates from humans. Resistance to tetracyclines+ and fluoroquinolones was more common and has recently emerged. Although acquired resistance in clinical L. monocytogenes did not implicate clinically relevant antibiotics, the possibility of resistance gene transfers, the description of the first clinical isolate with high-level resistance to trimethoprim, and the recent increase in penicillin MICs up to 2 μg/ml reinforce the need for microbiological surveillance.

scholarly journals Emergence of Penicillin-ResistantStreptococcus Pneumoniaein Southern Ontario, 1993–94

1995 ◽  
Vol 6 (3) ◽  
pp. 157-160 ◽  
Author(s):  
Andrew E Simor ◽  
Anita Rachlis ◽  
Lisa Louie ◽  
Janet Goodfellow ◽  
Marie Louie
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Tertiary Care ◽  
National Committee ◽  
In Vitro Susceptibility ◽  
Southern Ontario ◽  
Recent Emergence ◽  
Resistant Strains ◽  
High Level

Objective: To determine the prevalence of resistance ofStreptococcus pneumoniaeto penicillin and other antimicrobial agents in metropolitan Toronto.Design: Consecutive pneumococcal isolates from different patients were obtained from two private community-based laboratories and from patients assessed in the emergency department of a tertiary-care teaching hospital in Toronto, Ontario between June and December 1993, and between March and October 1994. In vitro susceptibility testing was done by broth microdilution in accordance with National Committee for Clinical Laboratory Standards guidelines.Results: Twenty (7.3±3.1%) of 274 pneumococcal isolates were resistant to penicillin; six (30%) isolates had high-level resistance (minimal inhibitory concentration [mic] 2.0 μg/mL or greater); and 14 isolates had intermediate resistance (mic0.1 to 1.0 μg/mL). Penicillin-resistant strains were also frequently resistant to tetracycline (55%), cotrimoxazole (50%), erythromycin (40%) and cefuroxime (35%). Resistant strains comprised several serotypes: 19F (six isolates), 9V (three), 23F (three), and one each of 6A, 6B, 14, and 19A; four isolates were nontypeable.Conclusions: There has been a recent emergence of penicillin-resistantS pneumoniaein southern Ontario. National and regional surveillance is warranted to determine the extent of the problem elsewhere in Canada.

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

1996 ◽  
Vol 40 (9) ◽  
pp. 2190-2193 ◽  
Author(s):  
A E Simor ◽  
M Louie ◽  
D E Low
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Beta Lactam ◽  
Surveillance Network ◽  
Antibiotic Resistant ◽  
Intermediate Resistance ◽  
Resistant Strains ◽  
High Level ◽  
Level Resistance

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

scholarly journals Susceptibility to antibiotics in escherichiae isolated in a multidisciplinary medical centre

2016 ◽  
Vol 65 (4) ◽  
pp. 83-89
Author(s):  
Nadezda S. Kozlova ◽  
Natalia E. Barantsevich ◽  
Elena P. Barantsevich
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
E Coli ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Resistant Strains ◽  
High Level

Relevance. Antimicrobial resistance in nosocomial strains currently presents a very important problem.  Aim of the study: Study of antibiotic resistance in Escherichia coli, isolated in a multidisciplinary centre.  Materials and Methods. Susceptibility of 151 E. coli strains to 15 antibiotics was studied by microdilution method. Results. The majority of the studied strains were resistant to antibiotics, including: ampicillin (57.0%), ciprofloxacin and moxifloxacin (42.4% each), III and IV generation cephalosporins (37.1% and 34.4%, respectively) and gentamycin (29.1%). The highest activity against E. coliwas shown for carbapenems (resistance to erthapenem – 2.6%, meropenem – 0.7%), in particular, for imipenem – no strains resistant to this drug were isolated. Resistance to amikacin and phosphomycin was low: 3.3% and 1.3% respectively. Wide diversity of antibiotic resistance spectra was revealed in studied strains, with a high level of multidrug resistance (48.0%). Conclusion. Study of susceptibility to antimicrobial agents in E. coli, isolated in a multidisciplinary centre, showed predominance of resistant strains with a high level of multidrug resistance. The appearance of carbapenem-resistant strains in a multidisciplinary centre presents a rising problem.

scholarly journals Culturing Ancient Bacteria Carrying Resistance Genes from Permafrost and Comparative Genomics with Modern Isolates

2020 ◽  
Vol 8 (10) ◽  
pp. 1522
Author(s):  
Pamela Afouda ◽  
Grégory Dubourg ◽  
Anthony Levasseur ◽  
Pierre-Edouard Fournier ◽  
Jeremy Delerce ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Acquired Resistance ◽  
Antibiotic Resistance Genes ◽  
Resistance Mechanisms ◽  
Genome Comparison ◽  
Antibiotics Use ◽  
High Level

Long considered to be a consequence of human antibiotics use by deduction, antibiotic resistance mechanisms appear to be in fact a much older phenomenon as antibiotic resistance genes have previously been detected from millions of year-old permafrost samples. As these specimens guarantee the viability of archaic bacteria, we herein propose to apply the culturomics approach to recover the bacterial content of a Siberian permafrost sample dated, using the in situ-produced cosmogenic nuclide chlorine36 (36Cl), at 2.7 million years to study the dynamics of bacterial evolution in an evolutionary perspective. As a result, we cultured and sequenced the genomes of 28 ancient bacterial species including one new species. To perform genome comparison between permafrost strains and modern isolates we selected 7 of these species (i.e., Achromobacter insolitus, Bacillus idriensis, Brevundimonas aurantiaca, Janibacter melonis, Kocuria rhizophila, Microbacterium hydrocarbonoxydans and Paracoccus yeei). We observed a high level of variability in genomic content with a percentage of shared genes in the core genomes ranging from 21.23% to 55.59%. In addition, the Single Nucleotide Polymorphism (SNP) comparison between permafrost and modern strains for the same species did not allow a dating of ancient strains based on genomic content. There were no significant differences in antibiotic resistance profiles between modern and ancient isolates of each species. Acquired resistance to antibiotics was phenotypically detected in all gram-negative bacterial species recovered from permafrost, with a significant number of genes coding for antibiotic resistance detected. Taken together, these findings confirm previously obtained data that antibiotic resistance predates humanity as most of antimicrobial agents are natural weapons used in inter-microbial conflicts within the biosphere.

scholarly journals Genetic and Pathogenic Variability of Mycogone perniciosa Isolates Causing Wet Bubble Disease on Agaricus bisporus in China

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 179
Author(s):  
Dan Li ◽  
Frederick Leo Sossah ◽  
Yang Yang ◽  
Zhenghui Liu ◽  
Yueting Dai ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Agaricus Bisporus ◽  
Aflp Analysis ◽  
Disease Management Strategy ◽  
Key Factor ◽  
Colony Color ◽  
Resistant Strains ◽  
Pathogenic Variability ◽  
Different Strains ◽  
High Level

Wet bubble disease, caused by Mycogone perniciosa, is a major threat to Agaricus bisporus production in China. In order to understand the variability of in genetic, pathogenicity, morphology, and symptom production of the fungus, 18 isolates of the pathogen were collected from diseased A. bisporus in different provinces in China. The isolates were characterized by a combination of morphological, cultural, and molecular pathogenicity testing on different strains of A. bisporus and amplified fragment length polymorphism (AFLP) analysis. The 18 isolates were identified by Koch’s postulate and confirmed different pathogenic variability among them. The yellow to brown isolates were more virulent than the white isolates. AFLP markers clustered the isolates into two distinct groups based on their colony color, with a high level of polymorphism of Jaccard similarities ranges from 0.39% to 0.64%. However, there was no evidence of an association between the genetic diversity and the geographical origin of the isolates. Through knowledge of the genetic diversity, phenotypic virulence of M. perniciosa is a key factor for successful breeding of resistant strains of A. bisporus and developing of an integrated disease management strategy to manage wet bubble disease of A. bisporus.

scholarly journals The life and times of the Enterococcus.

1990 ◽  
Vol 3 (1) ◽  
pp. 46-65 ◽  
Author(s):  
B E Murray
Keyword(s):  
Antimicrobial Agents ◽  
Acquired Resistance ◽  
Active Agent ◽  
Bactericidal Effect ◽  
Human Pathogens ◽  
A Cell ◽  
High Level ◽  
Tract Infections ◽  
Level Resistance ◽  
Resistance Traits

Enterococci are important human pathogens that are increasingly resistant to antimicrobial agents. These organisms were previously considered part of the genus Streptococcus but have recently been reclassified into their own genus, called Enterococcus. To date, 12 species pathogenic for humans have been described, including the most common human isolates, Enterococcus faecalis and E. faecium. Enterococci cause between 5 and 15% of cases of endocarditis, which is best treated by the combination of a cell wall-active agent (such as penicillin or vancomycin, neither of which alone is usually bactericidal) and an aminoglycoside to which the organism is not highly resistant; this characteristically results in a synergistic bactericidal effect. High-level resistance (MIC, greater than or equal to 2,000 micrograms/ml) to the aminoglycoside eliminates the expected bactericidal effect, and such resistance has now been described for all aminoglycosides. Enterococci can also cause urinary tract infections; intraabdominal, pelvic, and wound infections; superinfections (particularly in patients receiving expanded-spectrum cephalosporins); and bacteremias (often together with other organisms). They are now the third most common organism seen in nosocomial infections. For most of these infections, single-drug therapy, most often with penicillin, ampicillin, or vancomycin, is adequate. Enterococci have a large number of both inherent and acquired resistance traits, including resistance to cephalosporins, clindamycin, tetracycline, and penicillinase-resistant penicillins such as oxacillin, among others. The most recent resistance traits reported are penicillinase resistance (apparently acquired from staphylococci) and vancomycin resistance, both of which can be transferred to other enterococci. It appears likely that we will soon be faced with increasing numbers of enterococci for which there is no adequate therapy.

scholarly journals Antimicrobial resistance of Streptococcus pneumoniae recovered from outpatients in the United States during the winter months of 1994 to 1995: results of a 30-center national surveillance study.

1996 ◽  
Vol 40 (5) ◽  
pp. 1208-1213 ◽  
Author(s):  
G V Doern ◽  
A Brueggemann ◽  
H P Holley ◽  
A M Rauch
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Rank Order ◽  
The United States ◽  
Penicillin Resistance ◽  
National Committee ◽  
Medical Centers ◽  
Resistant Strains ◽  
High Level

A total of 1,527 clinically significant outpatient isolates of Streptococcus pneumoniae were prospectively collected in 30 different U.S. medical centers between November 1994 and April 1995. Overall, 23.6% of strains were not susceptible to penicillin, with 14.1% intermediate and 9.5% high-level resistant. The frequencies of recovery of intermediate and high-level resistant strains varied considerably between different medical centers and in different geographic areas. In general, intermediate and high-level penicillin resistance was most common with isolates of S. pneumoniae recovered from pediatric patients. The in vitro activities of 22 other antimicrobial agents were assessed against this collection of isolates. Ampicillin was consistently 1 twofold dilution less active than penicillin. Amoxicillin and amoxicillin-clavulanate were essentially equivalent to penicillin in activity. The rank order of activity for cephalosporins was cefotaxime = ceftriaxone > or = cefpodoxime > or = cefuroxime > cefprozil > or = cefixime > cefaclor = loracarbef > cefadroxil = cephalexin. The National Committee for Clinical Laboratory Standards [Performance Standards for Antimicrobial Susceptibility Testing, Sixth Information Supplement (M100-S6), 1995] has established MIC breakpoints for resistance (i.e., > or = 2 micrograms/ml) with three cephalosporins versus S. pneumoniae, namely, cefotaxime, ceftriaxone, and cefuroxime. The overall percentages of strains resistant to these three antimicrobial agents were 3, 5, and 12, respectively. The overall frequency of resistance was 10% with all three macrolides examined in this study, clarithromycin, erythromycin, and azithromycin. The overall percentages of chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole resistance were 4.3, 7.5, and 18, respectively. The resistance percentages among the cephalosporins, macrolides, chloramphenicol, tetracycline, and trimethoprim-sulfamethoxazole were consistently higher among penicillin-intermediate strains than among susceptible isolates and even higher still among organisms expressing high-level penicillin resistance. Multiply resistant strains represented 9.1% of the organisms examined in this study. Finally, rifampin resistance was uncommon (i.e., 0.5%), and vancomycin resistance was not detected. The quinopristin-dalfopristin combination was consistently active at concentrations of 0.25 to 4 micrograms/ml, but rates of resistance could not be determined in the absence of established interpretive criteria for MIC results.

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