Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 12 de 12
Filter
1.
Int J Antimicrob Agents ; 30(1): 72-7, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17428640

ABSTRACT

We report seven cases of infective endocarditis caused by USA300 methicillin-resistant Staphylococcus aureus (MRSA) at an urban, tertiary care, academic institution. Five strains were community associated and two were healthcare associated. All patients were injection drug users. Staphylococcus aureus isolates were characterised as USA300-type MRSA using pulsed-field gel electrophoresis. Five cases were right-sided endocarditis and two cases were left-sided. The mean length of in-hospital antimicrobial therapy was 23 days and the mean length of total antibiotic therapy was 55 days. Complications included heart failure resulting in valve replacement in one patient as well as death in that patient. As USA300 strains of MRSA continue to increase in prevalence, clinicians must be aware of the increasing spectrum of illness in considering management and prevention strategies.


Subject(s)
Endocarditis, Bacterial/microbiology , Methicillin Resistance , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/isolation & purification , Adolescent , Adult , Aged , Anti-Bacterial Agents/therapeutic use , Cluster Analysis , Community-Acquired Infections/microbiology , Cross Infection/microbiology , DNA Fingerprinting , Electrophoresis, Gel, Pulsed-Field , Endocarditis, Bacterial/complications , Endocarditis, Bacterial/drug therapy , Female , Hospitalization , Hospitals, Teaching , Hospitals, Urban , Humans , Length of Stay , Male , Middle Aged , Staphylococcal Infections/complications , Staphylococcal Infections/drug therapy , Staphylococcus aureus/classification , Substance Abuse, Intravenous/complications
2.
J Clin Microbiol ; 45(6): 1705-11, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17392441

ABSTRACT

Over a 2-year period (2003 to 2005) patients with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and community-acquired methicillin-susceptible Staphylococcus aureus (CA-MSSA) infections were prospectively identified. Patients infected with CA-MRSA (n = 102 patients) and CA-MSSA (n = 102 patients) had median ages of 46 and 53 years, respectively; the most common sites of infection in the two groups were skin/soft tissue (80 and 93%, respectively), respiratory tract (13 and 6%, respectively), and blood (4 and 1%, respectively). Fourteen percent of patients with CA-MRSA infections and 3% of patients with CA-MSSA infections had household contacts with similar infections (P < 0.01). Among the CA-MRSA isolates, the pulsed-field gel electrophoresis (PFGE) groups detected were USA300 (49%) and USA100 (13%), with 27 PFGE groups overall; 71% of the isolates were staphylococcal chromosome cassette mec (SCCmec) type IV, 29% were SCCmec type II, and 54% had the Panton-Valentine leucocidin (PVL) gene. Among the CA-MSSA isolates there were 33 PFGE groups, with isolates of the USA200 group comprising 11%, isolates of the USA600 group comprising 11%, isolates of the USA100 group comprising 10%, and isolates of the PVL type comprising 10%. Forty-six and 18% of the patients infected with CA-MRSA and CA-MSSA, respectively, were hospitalized (P < 0.001). Fifty percent of the patients received antibiotic therapy alone, 5% received surgery alone, 30% received antibiotics and surgery, 3% received other therapy, and 12% received no treatment. The median durations of antibiotic therapy were 12 and 10 days in the CA-MRSA- and CA-MSSA-infected patients, respectively; 48 and 56% of the patients in the two groups received adequate antimicrobial therapy, respectively (P < 0.001). The clinical success rates of the initial therapy in the two groups were 61 and 84%, respectively (P < 0.001); recurrences were more common in the CA-MRSA group (recurrences were detected in 18 and 6% of the patients in the two groups, respectively [P < 0.001]). CA-MRSA was an independent predictor of clinical failure in multivariate analysis (odds ratio, 3.4; 95% confidence interval, 1.7 to 6.9). In the community setting, the molecular characteristics of the S. aureus strains were heterogeneous. CA-MRSA infections were associated with a more adverse impact on outcome than CA-MSSA infections.


Subject(s)
Anti-Bacterial Agents , Community-Acquired Infections , Methicillin Resistance , Molecular Epidemiology , Staphylococcal Infections , Staphylococcus aureus/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacteremia/drug therapy , Bacteremia/epidemiology , Bacteremia/microbiology , Case-Control Studies , Community-Acquired Infections/drug therapy , Community-Acquired Infections/epidemiology , Community-Acquired Infections/microbiology , Female , Humans , Male , Methicillin/pharmacology , Microbial Sensitivity Tests , Middle Aged , Prevalence , Respiratory Tract Infections/drug therapy , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/microbiology , Risk Factors , Soft Tissue Infections/drug therapy , Soft Tissue Infections/epidemiology , Soft Tissue Infections/microbiology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/epidemiology , Staphylococcal Infections/microbiology , Staphylococcal Skin Infections/drug therapy , Staphylococcal Skin Infections/epidemiology , Staphylococcal Skin Infections/microbiology , Staphylococcus aureus/classification , Staphylococcus aureus/drug effects , Treatment Outcome
3.
J Clin Microbiol ; 44(9): 3361-5, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16954273

ABSTRACT

Three hundred sixty-one quinupristin-dalfopristin (Q-D)-resistant Enterococcus faecium (QDREF) isolates were isolated from humans, turkeys, chickens, swine, dairy and beef cattle from farms, chicken carcasses, and ground pork from grocery stores in the United States from 1995 to 2003. These isolates were evaluated by pulsed-field gel electrophoresis (PFGE) to determine possible commonality between QDREF isolates from human and animal sources. PCR was performed to detect the streptogramin resistance genes vatD, vatE, and vgbA and the macrolide resistance gene ermB to determine the genetic mechanism of resistance in these isolates. QDREF from humans did not have PFGE patterns similar to those from animal sources. vatE was found in 35%, 26%, and 2% of QDREF isolates from turkeys, chickens, and humans, respectively, and was not found in QDREF isolates from other sources. ermB was commonly found in QDREF isolates from all sources. Known streptogramin resistance genes were absent in the majority of isolates, suggesting the presence of other, as-yet-undetermined, mechanisms of Q-D resistance.


Subject(s)
Animals, Domestic/microbiology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/genetics , Enterococcus faecium/drug effects , Gram-Positive Bacterial Infections/microbiology , Meat/microbiology , Virginiamycin/pharmacology , Animals , Bacterial Proteins/genetics , Cattle/microbiology , Chickens/microbiology , Electrophoresis, Gel, Pulsed-Field , Enterococcus faecium/genetics , Enterococcus faecium/isolation & purification , Humans , Turkeys/microbiology , United States
4.
J Clin Microbiol ; 41(3): 1109-13, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12624037

ABSTRACT

We evaluated the molecular mechanism for resistance of 360 enterococci for which the gentamicin MICs were >/=128 micro g/ml. The aac(6')-Ie-aph(2")-Ia, aph(2")-Ic, and aph(2")-Id genes were identified by PCR in isolates from animals, food, and humans. The aph(2")-Ib gene was not identified in any of the isolates. Two Enterococcus faecalis isolates (MICs > 1,024 micro g/ml) from animals failed to generate a PCR product for any of the genes tested and likely contain a new unidentified aminoglycoside resistance gene. Pulsed-field gel electrophoresis (PFGE) analysis showed a diversity of strains. However, 1 human and 18 pork E. faecalis isolates from Michigan with the aac(6')-Ie-aph(2")-Ia gene had related PFGE patterns and 2 E. faecalis isolates from Oregon (1 human and 1 grocery store chicken isolate) had indistinguishable PFGE patterns. We found that when a gentamicin-resistant gene was present in resistant enterococci from animals, that gene was also present in enterococci isolated from food products of the same animal species. Although these data indicate much diversity among gentamicin-resistant enterococci, the data also suggest similarities in gentamicin resistance among enterococci isolated from humans, retail food, and farm animals from geographically diverse areas and provide evidence of the spread of gentamicin-resistant enterococci from animals to humans through the food supply.


Subject(s)
Animal Diseases/transmission , Enterococcus/drug effects , Food Microbiology , Gentamicins/pharmacology , Gram-Positive Bacterial Infections/transmission , Animals , Animals, Domestic/microbiology , Drug Resistance, Bacterial , Enterococcus/pathogenicity , Feces/microbiology , Gram-Positive Bacterial Infections/veterinary , Humans , Microbial Sensitivity Tests , United States
5.
J Clin Microbiol ; 40(12): 4659-65, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12454168

ABSTRACT

Thirty-five enterococcal isolates were recovered from dogs diagnosed with urinary tract infections at the Michigan State University Veterinary Teaching Hospital over a 2-year period (1996 to 1998). Isolated species included Enterococcus faecium (n = 13), Enterococcus faecalis (n = 7), Enterococcus gallinarum (n = 11), and Enterococcus casseliflavus (n = 4). Antimicrobial susceptibility testing revealed several different resistance phenotypes, with the majority of the enterococcal isolates exhibiting resistance to three or more antibiotics. One E. faecium isolate, CVM1869, displayed high-level resistance to vancomycin (MIC > 32 micro g/ml) and gentamicin (MIC > 2,048 micro g/ml). Molecular analysis of this isolate revealed the presence of Tn1546 (vanA), responsible for high-level vancomycin resistance, and Tn5281 carrying aac6'-aph2", conferring high-level aminoglycoside resistance. Pulsed-field gel electrophoresis analysis revealed that CVM1869 was a canine E. faecium clone that had acquired Tn1546, perhaps from a human vancomycin-resistant E. faecium. Transposons Tn5281 and Tn1546 were located on two different conjugative plasmids. Sequence analysis revealed that in Tn1546, ORF1 had an 889-bp deletion and an IS1216V insertion at the 5' end and an IS1251 insertion between vanS and vanH. To date, this particular form of Tn1546 has only been described in human clinical vancomycin-resistant enterococcus isolates unique to the United States. Additionally, this is the first report of a vancomycin-resistant E. faecium isolated from a companion animal in the United States.


Subject(s)
Conjugation, Genetic , DNA Transposable Elements/genetics , Dog Diseases/microbiology , Enterococcus faecium/drug effects , Urinary Tract Infections/veterinary , Vancomycin Resistance/genetics , Animals , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Carbon-Oxygen Ligases/genetics , Dogs , Drug Resistance, Multiple, Bacterial , Electrophoresis, Gel, Pulsed-Field , Enterococcus faecium/genetics , Enterococcus faecium/isolation & purification , Gene Transfer, Horizontal , Gentamicins/pharmacology , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/veterinary , Humans , Microbial Sensitivity Tests , Plasmids/genetics , Urinary Tract Infections/microbiology , Vancomycin/pharmacology
6.
Antimicrob Agents Chemother ; 44(10): 2876-9, 2000 Oct.
Article in English | MEDLINE | ID: mdl-10991878

ABSTRACT

A new high-level gentamicin resistance gene, designated aph(2")-Ib, was cloned from Enterococcus faecium SF11770. The deduced amino acid sequence of the 897-bp open reading frame of aph(2")-Ib shares homology with the aminoglycoside-modifying enzymes AAC(6')-APH(2"), APH(2")-Ic, and APH(2")-Id. The observed phosphotransferase activity is designated APH(2")-Ib.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins , Enterococcus faecium/drug effects , Enterococcus faecium/genetics , Phosphotransferases (Alcohol Group Acceptor)/biosynthesis , Cloning, Molecular , DNA, Bacterial/genetics , Drug Resistance, Microbial , Escherichia coli/drug effects , Escherichia coli/genetics , Gentamicins/pharmacology , Molecular Sequence Data , Open Reading Frames/genetics , Phosphotransferases (Alcohol Group Acceptor)/genetics , Plasmids/genetics , Sequence Homology, Nucleic Acid
7.
Antimicrob Agents Chemother ; 44(9): 2545-6, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10952613

ABSTRACT

Enterococcus faecalis LC40 is an ampicillin-susceptible clinical isolate with high-level gentamicin resistance due to the aac(6')-Ie-aph(2")-Ia aminoglycoside resistance gene. The combination of ampicillin plus arbekacin reduced mean bacterial vegetation counts significantly more than ampicillin alone or ampicillin plus gentamicin in a rabbit model of aortic-valve endocarditis caused by E. faecalis LC40.


Subject(s)
Aminoglycosides , Ampicillin/therapeutic use , Anti-Bacterial Agents/therapeutic use , Dibekacin/analogs & derivatives , Dibekacin/therapeutic use , Drug Therapy, Combination/therapeutic use , Endocarditis, Bacterial/drug therapy , Gram-Positive Bacterial Infections/drug therapy , Animals , Anti-Bacterial Agents/pharmacology , Disease Models, Animal , Drug Resistance, Microbial/physiology , Endocarditis, Bacterial/microbiology , Enterococcus faecalis/drug effects , Gentamicins/pharmacology , Gram-Positive Bacterial Infections/microbiology , Microbial Sensitivity Tests , Rabbits , Treatment Outcome
8.
Antimicrob Agents Chemother ; 42(5): 1229-32, 1998 May.
Article in English | MEDLINE | ID: mdl-9593155

ABSTRACT

Enterococcus casseliflavus UC73 is a clinical blood isolate with high-level resistance to gentamicin. DNA preparations from UC73 failed to hybridize with intragenic probes for aac(6')-Ie-aph(2'')-Ia and aph(2'')-Ic. A 4-kb fragment from UC73 was cloned and found to confer resistance to gentamicin in Escherichia coli DH5alpha transformants. Nucleotide sequence analysis revealed the presence of a 906-bp open reading frame whose deduced amino acid sequence had a region with homology to the aminoglycoside-modifying enzyme APH(2'')-Ic and to the C-terminal domain of the bifunctional enzyme AAC(6')-APH(2''). The gene is designated aph(2'')-Id, and its observed phosphotransferase activity is designated APH(2'')-Id. A PCR-generated intragenic probe hybridized to the genomic DNA from 17 of 118 enterococcal clinical isolates (108 with high-level gentamicin resistance) from five hospitals. All 17 were vancomycin-resistant Enterococcus faecium isolates, and pulsed-field typing revealed three distinct clones. The combination of ampicillin plus either amikacin or neomycin exhibited synergistic killing against E. casseliflavus UC73. Screening and interpretation of high-level aminoglycoside resistance in enterococci may need to be modified to include detection of APH(2'')-Id.


Subject(s)
Bacterial Proteins , Drug Resistance, Microbial/genetics , Enterococcus/genetics , Genes, Bacterial/genetics , Phosphotransferases (Alcohol Group Acceptor)/genetics , Anti-Bacterial Agents/pharmacology , Enterococcus/drug effects , Gentamicins/pharmacology , Phosphotransferases/metabolism
9.
Diagn Microbiol Infect Dis ; 32(3): 141-6, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9884829

ABSTRACT

Enterococci with gentamicin MICs of 256 to 1,024 micrograms/mL were evaluated for susceptibility to ampicillin plus gentamicin synergism. Sixteen of eighteen enterococcal isolates were not susceptible to synergistic killing by ampicillin plus gentamicin; 11 possessed aac(6')-aph(2"), and 4 possessed aph(2")-Ic. A gentamicin MIC of 512 or 1,024 micrograms/mL predicted lack of ampicillin/gentamicin synergism, but a gentamicin MIC of 256 micrograms/mL did not. For six enterococcal strains possessing the gentamicin-resistance gene aph(2")-Ic, ampicillin plus dibekacin, ampicillin plus netilmicin, and ampicillin plus amikacin produced synergistic killing in five, three, and two strains, respectively.


Subject(s)
Ampicillin/pharmacology , Enterococcus faecium/drug effects , Gentamicins/pharmacology , Penicillins/pharmacology , Amikacin/pharmacology , Amikacin/therapeutic use , Ampicillin/therapeutic use , Animals , DNA Primers/chemistry , DNA Probes/chemistry , DNA Restriction Enzymes , Dibekacin/pharmacology , Dibekacin/therapeutic use , Drug Resistance, Microbial/genetics , Drug Synergism , Electrophoresis, Agar Gel , Enterococcus faecium/genetics , Gentamicins/therapeutic use , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Bacterial Infections/microbiology , Humans , Microbial Sensitivity Tests , Netilmicin/pharmacology , Netilmicin/therapeutic use , Penicillins/therapeutic use , Polymerase Chain Reaction
10.
Antimicrob Agents Chemother ; 41(3): 511-4, 1997 Mar.
Article in English | MEDLINE | ID: mdl-9055984

ABSTRACT

Enterococcus gallinarum SF9117 is a veterinary isolate for which the MIC of gentamicin is 256 micrograms/ml. Time-kill studies with a combination of ampicillin plus gentamicin failed to show synergism against SF9117. A probe representing aac(6')-aph(2") did not hybridize to DNA from SF9117. A 3.2-kb fragment from plasmid pYN134 of SF9117 was cloned and conferred resistance to gentamicin in Escherichia coli DH5 alpha. Nucleotide sequence analysis revealed the presence of a 918-bp open reading frame whose deduced amino acid sequence had a region with homology to the C-terminal domain of the bifunctional enzyme AAC(6')-APH(2"). The gene is designated aph(2")-Ic, and its observed phosphotransferase activity is provisionally designated APH(2")-Ic. An intragenic probe hybridized to the genomic DNA from an Enterococcus faecium isolate from the peritoneal fluid of one patient and to the plasmid DNA of an Enterococcus faecalis isolate from the blood of another patient. An enterococcal isolate containing this novel resistance gene might not be readily detected in clinical laboratories that use gentamicin at 500 or 2,000 micrograms/ml for screening for high-level resistance.


Subject(s)
Anti-Bacterial Agents/pharmacology , Enterococcus/drug effects , Enterococcus/genetics , Genes, Bacterial/genetics , Gentamicins/pharmacology , Amino Acid Sequence , Base Sequence , Cloning, Molecular , Culture Media , DNA, Bacterial/isolation & purification , Drug Resistance, Microbial , Humans , Microbial Sensitivity Tests , Molecular Sequence Data , Polymerase Chain Reaction , Wound Infection/microbiology
11.
Antimicrob Agents Chemother ; 37(11): 2474-7, 1993 Nov.
Article in English | MEDLINE | ID: mdl-8285637

ABSTRACT

A rabbit endocarditis model was utilized to evaluate the virulence conferred by the conjugative plasmid pAD1 with the following strains: Enterococcus faecalis plasmid-free FA2-2 and FA2-2 containing plasmids pAD1 (hemolysin and aggregation substance positive), pAM9058 (insertional inactivation of hemolysin), and pAM944 or pAM947 (insertional inactivation of aggregation substance). All isolates were similar in ability to produce endocarditis. Mean vegetation weight was greater in animals inoculated with strains that produced aggregation substance (P < 0.01). Mortality was significantly increased in animals given FA2-2 containing pAD1 compared with those given all other strains (P < 0.01). These results suggest that the combination of hemolysin and aggregation substance is associated with increased mortality and that vegetation weight is associated with production of aggregation substance in experimental E. faecalis endocarditis.


Subject(s)
Bacterial Proteins/biosynthesis , Endocarditis, Bacterial/metabolism , Enterococcus faecalis , Gram-Positive Bacterial Infections/metabolism , Hemolysin Proteins/metabolism , Plasmids , Sex Attractants/biosynthesis , Animals , Bacterial Proteins/genetics , Colony Count, Microbial , Endocarditis, Bacterial/microbiology , Endocarditis, Bacterial/pathology , Enterococcus faecalis/genetics , Enterococcus faecalis/metabolism , Female , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/pathology , Rabbits , Sex Attractants/genetics
12.
J Clin Microbiol ; 30(11): 2757-61, 1992 Nov.
Article in English | MEDLINE | ID: mdl-1333477

ABSTRACT

Molecular typing methods were compared by using 66 ampicillin-resistant, non-beta-lactamase-producing Enterococcus faecium clinical isolates from diverse geographic areas. Whole-plasmid analysis, restriction enzyme analysis of plasmid DNA with EcoRI and HindIII, and contour-clamped homogeneous electric field electrophoresis with digestion by SmaI and ApaI were performed on all isolates. Whole-plasmid analysis identified 47 different groups. Restriction enzyme analysis of plasmid DNA identified 50 groups when EcoRI was used and 51 groups when HindIII was used. Results with EcoRI and HindIII differed in 9 of 66 isolates. Grouping results with whole-plasmid analysis differed from results of restriction enzyme analysis of plasmid DNA (combining EcoRI and HindIII) in 20 of 66 isolates. Contour-clamped homogeneous electric field electrophoresis identified 46 groups when SmaI was used and 44 groups when ApaI was used. Results with SmaI and ApaI differed in 3 of 66 isolates. Grouping results with contour-clamped homogeneous electric field electrophoresis (combining SmaI and ApaI) differed from results of restriction enzyme analysis of plasmid DNA (combining EcoRI and HindIII) in 17 of 66 isolates. The combined use of whole-plasmid analysis, restriction enzyme analysis of plasmid DNA with two enzymes, and contour-clamped homogeneous electric field electrophoresis with two restriction enzymes should be considered when E. faecium is typed for epidemiologic investigation.


Subject(s)
Enterococcus faecium/classification , Ampicillin Resistance , Bacterial Typing Techniques , DNA Restriction Enzymes , DNA, Bacterial/genetics , Electrophoresis , Enterococcus faecium/genetics , Enterococcus faecium/isolation & purification , Gram-Positive Bacterial Infections/epidemiology , Gram-Positive Bacterial Infections/microbiology , Humans , Plasmids , beta-Lactamases/biosynthesis
SELECTION OF CITATIONS
SEARCH DETAIL
...