scholarly journals An Enterococcus faecalis ABC Homologue (Lsa) Is Required for the Resistance of This Species to Clindamycin and Quinupristin-Dalfopristin

2002 ◽  
Vol 46 (6) ◽  
pp. 1845-1850 ◽  
Author(s):  
Kavindra V. Singh ◽  
George M. Weinstock ◽  
Barbara E. Murray
Keyword(s):  
Staphylococcus Aureus ◽  
Lactococcus Lactis ◽  
Enterococcus Faecalis ◽  
Parental Strain ◽  
Enterococcus Faecium ◽  
Wild Type ◽  
Abc Proteins ◽  
Binding Motifs ◽  
Intrinsic Gene ◽  
Characteristic Resistance

ABSTRACT Enterococcus faecalis isolates are resistant to clindamycin (CLI) and quinupristin-dalfopristin (Q-D), and this is thought to be a species characteristic. Disruption of a gene (abc-23, now designated lsa, for “lincosamide and streptogramin A resistance”) of E. faecalis was associated with a ≥40-fold decrease in MICs of Q-D (to 0.75 μg/ml), CLI (to 0.12 to 0.5 μg/ml), and dalfopristin (DAL) (to 4 to 8 μg/ml) for the wild-type E. faecalis parental strain (Q-D MIC, 32 μg/ml; CLI MIC, 32 to 48 μg/ml; DAL MIC, 512 μg/ml). Complementation of the disruption mutant with lsa on a shuttle plasmid resulted in restoration of the MICs of CLI, Q-D, and DAL to wild-type levels. Under high-stringency conditions, lsa was found in 180 of 180 isolates of E. faecalis but in none of 189 other enterococci. Among 19 erm(B)-lacking Enterococcus faecium strains, 9 (47%) were highly susceptible to CLI (MIC, 0.06 to 0.25 μg/ml) and had DAL MICs of 4 to 16 μg/ml; for the remaining erm(B)-lacking E. faecium strains, the CLI and DAL MICs were 4 to >256 and 2 to >128 μg/ml, respectively. In contrast, none of 32 erm(B)-lacking E. faecalis strains were susceptible (CLI MIC range, 16 to 32 μg/ml; DAL MIC range, ≥32 μg/ml). When lsa was introduced into an E. faecium strain initially susceptible to CLI, the MICs of CLI and DAL increased ≥60-fold and that of Q-D increased 6-fold (to 3 to 6 μg/ml). Introduction of lsa into two DAL-resistant (MICs, >128 μg/ml), Q-D-susceptible (MICs, 0.5 and 1.5 μg/ml) E. faecium strains (CLI MICs, 12 and >256 μg/ml) resulted in an increase in the Q-D MICs from 3- to 10-fold (to 8 and >32 μg/ml), respectively. Although efflux was not studied, the similarity (41 to 64%) of the predicted Lsa protein to ABC proteins such as Vga(A), Vga(B), and Msr(A) of Staphylococcus aureus and YjcA of Lactococcus lactis and the presence of Walker A and B ATP-binding motifs suggest that this resistance may be related to efflux of these antibiotics. In conclusion, lsa appears to be an intrinsic gene of E. faecalis that explains the characteristic resistance of this species to CLI and Q-D.

scholarly journals Efeito antimicrobiano do extrato de Cranberry sobre micro-organismos causadores de infecção urinária

2016 ◽  
Vol 11 (31) ◽  
pp. 113-122
Author(s):  
Carla Franco Porto Belmont Souza ◽  
Luiz Eduardo Souza da Silva Irineu ◽  
Renan Silva De Souza ◽  
Renato da Silva Teixeira ◽  
Ivina Sanches Pereira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Proteus Mirabilis ◽  
Enterococcus Faecium ◽  
Vaccinium Macrocarpon ◽  
Mueller Hinton

A resistência microbiana tem se mostrado um problema de proporções mundiais, causando estado de morbidade e mortalidade em diversos pacientes. Em vista disso, tem crescido a busca por métodos alternativos naturais de profilaxia. A investigação clínica sugere que o Extrato de Cranberry está entre as melhores propostas de prevenção natural. O Cranberry (Vaccinium macrocarpon) é um fruto que tem crescido comercialmente pelo sabor e propriedades benéficas à saúde. Dentre as formas comercializadas estão: o suco, o chá e as cápsulas contendo o extrato seco. A ação desta planta está relacionada ao tratamento de doenças do trato urinário, por possuir substâncias que inibem a adesão bacteriana ao epitélio do trato urinário, dificultando sua proliferação e reprodução. Dentre todas as infecções relacionadas à assistência a saúde, a Infecção do Trato Urinário é a mais frequentemente associada a procedimentos invasivos. Se não for tratada, pode resultar em complicações como pielonefrite aguda, bacteremia e pionefrose. Portanto, cranberry pode ser uma nova alternativa para o combate das infecções uroepiteliais, por ser um produto natural de preço acessível, e com formas de comercialização diversificada, ao contrário dos antimicrobianos convencionais, que por sua vez são caros e podem acabar causando resistência nos micro-organismos. Este trabalho teve como objetivo avaliar in vitro a atividade antimicrobiana do extrato de Cranberry, adquirido em farmácia de manipulação, sobre 8 micro-organismos isolados de infecções urinárias. As cepas utilizadas, adquiridas da coleção da FIOCRUZ, foram: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Serratia marscecens, Staphylococcus aureus, Enterococcus faecalis e Enterococcus faecium. No estudo, foram utilizados o caldo Mueller Hinton (MH), Extrato de Cranberry e as bactérias patogênicas. O ensaio foi realizado em triplicata, com o uso de um controle de crescimento dos micro-organismos e o experimento para avaliação do crescimento bacteriano na presença do extrato. A turbidez foi medida com o auxílio de um espectrofotômetro, no comprimento de onda de 600 nm, antes e após 24 horas de incubação à 37 ºC. O procedimento forneceu a Densidade Ótica, do qual possibilitou a identificação da inibição microbiana. Para análise estatística foi utilizado o Teste t de Student. O Extrato de Cranberry apresentou atividade antimicrobiana sobre as bactérias Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Serratia marscecens e Enterococcus faecalis (p < 0,05), confirmando seu efeito benéfico em infecções urinárias. No entanto, não teve efeito inibitório significativo sobre Pseudomonas aeruginosa, Proteus mirabilis e Enterococcus faecium (p > 0,05).

scholarly journals Influence of the Protein Kinase C Activator Phorbol Myristate Acetate on the Intracellular Activity of Antibiotics against Hemin- and Menadione-Auxotrophic Small-Colony Variant Mutants of Staphylococcus aureus and Their Wild-Type Parental Strain in Human THP-1 Cells

2012 ◽  
Vol 56 (12) ◽  
pp. 6166-6174 ◽  
Author(s):  
Laetitia G. Garcia ◽  
Sandrine Lemaire ◽  
Barbara C. Kahl ◽  
Karsten Becker ◽  
Richard A. Proctor ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Parental Strain ◽  
Wild Type ◽  
Content Type ◽  
Small Colony Variant ◽  
Intracellular Activity ◽  
Kinase C ◽  
Pharmacodynamic Profile ◽  
Small Colony ◽  
Intracellular Fate

ABSTRACTIn a previous study (L. G. Garcia et al., Antimicrob. Agents Chemother. 56:3700–3711, 2012), we evaluated the intracellular fate ofmenDandhemBmutants (corresponding to menadione- and hemin-dependent small-colony variants, respectively) of the parental COL methicillin-resistantStaphylococcus aureusstrain and the pharmacodynamic profile of the intracellular activity of a series of antibiotics in human THP-1 monocytes. We have now examined the phagocytosis and intracellular persistence of the same strains in THP-1 cells activated by phorbol 12-myristate 13-acetate (PMA) and measured the intracellular activity of gentamicin, moxifloxacin, and oritavancin in these cells. Postphagocytosis intracellular counts and intracellular survival were lower in PMA-activated cells, probably due to their higher killing capacities. Gentamicin and moxifloxacin showed a 5- to 7-fold higher potency (lower static concentrations) against the parental strain, itshemBmutant, and the genetically complemented strain in PMA-activated cells and against themenDstrain in both activated and nonactivated cells. This effect was inhibited when cells were incubated withN-acetylcysteine (a scavenger of oxidant species). In parallel, we observed that the MICs of these drugs were markedly reduced if bacteria had been preexposed to H2O2. In contrast, the intracellular potency of oritavancin was not different in activated and nonactivated cells and was not decreased by the addition ofN-acetylcysteine, regardless of the phenotype of the strains. The oritavancin MIC was also unaffected by preincubation of the bacteria with H2O2. Thus, activation of THP-1 cells by PMA may increase the intracellular potency of certain antibiotics (probably due to synergy with reactive oxygen species), but this effect cannot be generalized to all antibiotics.

scholarly journals Comparative In Vitro Activities and Postantibiotic Effects of the Oxazolidinone Compounds Eperezolid (PNU-100592) and Linezolid (PNU-100766) versus Vancomycin against Staphylococcus aureus, Coagulase-Negative Staphylococci, Enterococcus faecalis, and Enterococcus faecium

1998 ◽  
Vol 42 (3) ◽  
pp. 721-724 ◽  
Author(s):  
Michael J. Rybak ◽  
Diane M. Cappelletty ◽  
Tabitha Moldovan ◽  
Jeffrey R. Aeschlimann ◽  
Glenn W. Kaatz
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Inhibitory Activity ◽  
Enterococcus Faecium ◽  
Antibacterial Agents ◽  
Clinical Isolates ◽  
Postantibiotic Effect ◽  
Coagulase Negative Staphylococci ◽  
Time Kill

ABSTRACT The activities of the oxazolidinone antibacterial agents eperezolid (PNU-100592) and linezolid (PNU-100766) were compared with that of vancomycin against clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus (n = 200), coagulase-negative staphylococci (n = 100), and vancomycin-susceptible and -resistant Enterococcus faecalisand Enterococcus faecium (n = 50). Eperezolid and linezolid demonstrated good in vitro inhibitory activity, regardless of methicillin susceptibility for staphylococci (MIC at which 90% of the isolates are inhibited [MIC90] range, 1 to 4 μg/ml) or vancomycin susceptibility for enterococci (MIC90 range, 1 to 4 μg/ml). In time-kill studies, eperezolid and linezolid were bacteriostatic in action. A postantibiotic effect of 0.8 ± 0.5 h was demonstrated for both eperezolid and linezolid against S. aureus, S. epidermidis, E. faecalis, and E. faecium.

scholarly journals Active efflux of antimicrobial agents in wild-type strains of enterococci.

1997 ◽  
Vol 41 (4) ◽  
pp. 869-871 ◽  
Author(s):  
C Lynch ◽  
P Courvalin ◽  
H Nikaido
Keyword(s):  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Antimicrobial Agents ◽  
Wild Type ◽  
Active Efflux ◽  
Energy Dependent ◽  
Reference Strains ◽  
Type Strains

Enterococci are intrinsically resistant to numerous antimicrobial agents. We examined the energy-dependent efflux of radiolabeled drugs from four reference strains of Enterococcus faecalis and a strain of Enterococcus faecium and found that most strains pumped out norfloxacin and chloramphenicol. Efflux of tetracycline was detected only in certain strains.

Prevalence of the aminoglycoside phosphotransferase genes aph(3′)-IIIa and aph(3′)-IIa in Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and Staphylococcus aureus isolates in Austria

2014 ◽  
Vol 63 (2) ◽  
pp. 210-217 ◽  
Author(s):  
Markus Woegerbauer ◽  
Josef Zeinzinger ◽  
Burkhard Springer ◽  
Peter Hufnagl ◽  
Alexander Indra ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Resistance Gene ◽  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Salmonella Enterica ◽  
Gene Pool ◽  
Human Pathogens ◽  
Aminoglycoside Phosphotransferase

The aminoglycoside phosphotransferase aph(3′)-IIa primarily inactivates kanamycin and neomycin, whilst aph(3′)-IIIa also inactivates amikacin. The aim of this study was to determine the frequency of both resistance genes in major human pathogens to obtain their baseline prevalence in the gene pool of these bacterial populations in Austria. In total, 10 541 Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and Staphylococcus aureus isolates were collected representatively without selection bias between 2008 and 2011. Isolates were analysed by aph(3′)-IIIa/nptIII- and aph(3′)-IIa/nptII-specific TaqMan real-time PCR. For positive strains, MICs using Etests were performed and resistance gene sequences were determined. The overall prevalence of aph(3′)-IIIa/nptIII was 1.62 % (95 % confidence interval: 1.38–1.88 %). In Escherichia coli, enterococci, Staphylococcus aureus, P. aeruginosa and Salmonella spp., the aph(3′)-IIIa/nptIII prevalence was 0.47 % (0–1.47 %), 37.53 % (32.84–42.40 %), 2.90 % (1.51–5.02 %), 0 % (0–0.32 %) and 0 % (0–0.037 %), respectively. Eleven of a total of 169 carriers showed single-nucleotide polymorphisms in the resistance allele. The overall prevalence of aph(3′)-IIa/nptII was 0.0096 % (0–0.046 %). Escherichia coli (0–0.70 %), enterococci (0–0.75 %), Staphylococcus aureus (0–0.73 %) and P. aeruginosa (0–0.32 %) did not carry aph(3′)-IIa. A single Salmonella isolate was positive, resulting in an aph(3′)-IIa prevalence of 0.013 % (0–0.058 %). aph(3′)-IIIa/nptIII carriers were moderately prevalent in the strains tested except for in enterococci, which appeared to be an important reservoir for aph(3′)-IIIa. aph(3′)-IIa/nptII genes were detected at clinically irrelevant frequencies and played no significant role in the aminoglycoside resistance gene pool during the observation period.

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