Antimicrobial Agents and Chemotherapy
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Update to the Multiplex PCR Strategy for Assignment of <i>mec</i> Element Types in <i>Staphylococcus aureus</i> ABSTRACT
Staphylococcal cassette chromosome
mec
(SCC
mec
) typing is important for the identification and definition of methicillin-resistant
Staphylococcus aureus
clones, and for routine purposes, multiplex PCR assays are the most adequate for SCC
mec
typing. Here, we describe an update to the multiplex PCR strategy for SCC
mec
typing that we described in 2002 so that SCC
mec
types IV and V may be properly identified.
Antimicrobial Agents and Chemotherapy - Tập 51 Số 9 - Trang 3374-3377 - 2007
Multiplex PCR Strategy for Rapid Identification of Structural Types and Variants of the <i>mec</i> Element in Methicillin-Resistant <i>Staphylococcus aureus</i> ABSTRACT
Full characterization of methicillin-resistant
Staphylococcus aureus
(MRSA) requires definition of not only the bacterial genetic background but also the structure of the complex and heterologous
mec
element these bacteria carry, which is associated with drug resistance determinant
mecA
. We report the development, validation, and application of a multiplex PCR strategy that allows quick presumptive characterization of the
mec
element types based on the structural features that were shown to be typical of
mec
elements carried by several MRSA clones. The strategy was validated by using a representative collection of pandemic MRSA clones in which the full structure of the associated
mec
elements was previously determined by hybridization and PCR screenings and also by DNA sequencing. The method was tested together with multilocus sequence typing and other typing methods for the characterization of 18 isolates representative of the MRSA clones recovered during a hospital outbreak in Barcelona, Spain. The multiplex PCR was shown to be rapid, robust, and capable in a single assay of identifying five structural types of the
mec
element among these strains, three major and two minor variants, each one of which has been already been seen among MRSA characterized earlier. This technique should be a useful addition to the armamentarium of molecular typing tools for the characterization of MRSA clonal types and for the rapid tentative identification of structural variants of the
mec
element.
Antimicrobial Agents and Chemotherapy - Tập 46 Số 7 - Trang 2155-2161 - 2002
Correlation of in vitro fluconazole resistance of Candida isolates in relation to therapy and symptoms of individuals seropositive for human immunodeficiency virus type 1 Yeast strains isolated from the oropharynx of 87 consecutive patients infected with human immunodeficiency virus type 1 were examined for in vitro susceptibility to fluconazole. Candida albicans was isolated from 73 patients. Fifty-one patients had received antifungal therapy in the month preceding the yeast infection. Thirty-two patients had symptomatic oropharyngeal candidiasis. The MICs were correlated with azole use and with clinical symptoms and signs. Although there is overlap between groups, in vitro testing identified a large group of patients for whose yeast isolates the fluconazole MICs were high and who remained symptomatic while receiving azole therapy. This study supports the ability of in vitro testing to predict the clinical outcome of mucosal fungal infections. The study also demonstrates that azole resistance of oropharyngeal yeasts is a common problem in patients infected with human immunodeficiency virus type 1 and that this azole resistance has clinical relevance.
Antimicrobial Agents and Chemotherapy - Tập 37 Số 11 - Trang 2449-2453 - 1993
Replacement of Broad-Spectrum Cephalosporins by Piperacillin-Tazobactam: Impact on Sustained High Rates of Bacterial Resistance ABSTRACT
We have previously observed a significant reduction of ceftriaxone resistance in
Proteus mirabilis
associated with an increase in the use of cefepime, along with a decrease in the consumption of broad-spectrum cephalosporins (CEP). However, we did not observe such a reduction with
Klebsiella pneumoniae
. Therefore, we sought to determine whether replacement of CEP by piperacillin-tazobactam might be useful in reducing sustained high rates of CEP resistance by this organism. We used a 6-month “before and after model”; during the second (intervention) period, most prescriptions of CEP were changed to piperacillin-tazobactam at the pharmacy. No additional barrier precautions were undertaken. During intervention, consumption of ceftazidime decreased from 17.73 to 1.14 defined daily doses (DDD) per 1,000 patient-days (
P
< 0.0001), whereas that of piperacillin-tazobactam increased from 0 to 30.57 DDD per 1,000 patient-days (
P
< 0.0001). The levels of resistance to CEP by
K. pneumoniae
and
P. mirabilis
decreased from 68.4 and 57.9% to 37.5 and 29.4%, respectively (
P
< 0.05). We conclude that replacement of ceftazidime by piperacillin-tazobactam might be a suitable strategy to decrease endemic CEP resistance by
K. pneumoniae
and
P. mirabilis
, even where there are high bacterial resistance rates and irrespective of any additional precautions for controlling nosocomial infection.
Antimicrobial Agents and Chemotherapy - Tập 48 Số 2 - Trang 392-395 - 2004
Epidemiology and Successful Control of a Large Outbreak Due to <i>Klebsiella pneumoniae</i> Producing ExtendedSpectrum β-Lactamases ABSTRACT
An outbreak due to extended-spectrum β-lactamase-producing
Klebsiella pneumoniae
(ESBL-KP) was detected from May 1993 to June 1995. A total of 145 patients, particularly patients in intensive care units (ICUs) (107 patients [72%]), were colonized or infected. Infection developed in 92 (63%) patients, and primary bacteremia caused by ESBL-KP was the most frequent infection (40 of 92 patients [43%]). A single clone of ESBL-KP was identified by pulsed-field gel electrophoresis analysis throughout the whole period, and no molecular epidemiological relationship could be found between the epidemic strain and non-ESBL-KP isolates. To determine risk factors for ESBL-KP infection weekly rectal swabs were obtained in three serial incidence surveys (470 patients); the probabilities of carriage of ESBL-KP in the digestive tract were 33% (October and November 1993), 40% (May and June 1994), and 0% (October and November 1995) at 10 days of ICU admission. A logistic regression model identified prior carriage of ESBL-KP in the digestive tract (odds ratio, 3.4; 95% confidence interval 1.1 to 10.4) as an independent variable associated with ESBL-KP infection. A statistically significant correlation was observed between the restricted use of oxyimino-β-lactams (189 defined daily doses [DDD]/1,000 patient-days to 24 DDD/1,000 patient-days) and the trends of ESBL-KP infection (
r
= 0.7;
P
= 0.03).
Antimicrobial Agents and Chemotherapy - Tập 42 Số 1 - Trang 53-58 - 1998
Hoạt tính in vitro của linezolid đối với nhóm Mycobacteria không lao tăng trưởng chậm
Antimicrobial Agents and Chemotherapy - Tập 47 Số 5 - Trang 1736-1738 - 2003
Các nồng độ ức chế tối thiểu (MIC) của linezolid trong nghiệm pháp vi pha loãng trong canh thang đã được thử nghiệm trên 341 chủng Mycobacteria không lao tăng trưởng chậm (NTM) thuộc 15 loài. Các giá trị MIC được đề xuất cho thấy tất cả các chủng Mycobacterium marinum, Mycobacterium szulgai, Mycobacterium kansasii, Mycobacterium malmoense và Mycobacterium xenopi, cũng như 90% các chủng Mycobacterium gordonae và Mycobacterium triplex, đều ≤8 μg/ml. Linezolid có tiềm năng điều trị xuất sắc đối với hầu hết các loài NTM.
High-pressure liquid chromatographic quantitation of azlocillin We describe a rapid, precise, and simple procedure for the quantitation of azlocillin in serum and in aqueous solutions by high-pressure, reverse-phase liquid chromatography. This method uses a single precipitation step, detection by dual-wavelength monitoring (220 and 254 nm), and quantitation by comparison with an internal standard. The 10-micron C18 muBondapak column was eluted with 45% (vol/vol) methanol-65% (vol/vol) phosphate buffer. The precision was 4.2 and 5.6% at 50 and 10 micrograms/ml, respectively. The assay was linear up to concentrations of 100 micrograms/ml, with recoveries of 90.4 to 110.5% from serum. The assay was sensitive to 0.4 micrograms of azlocillin per ml. The short turnover time (14 min) and small serum sample size (20 microliters) make the assay ideal for therapeutic drug monitoring and clinical pharmacokinetic studies.
Antimicrobial Agents and Chemotherapy - Tập 24 Số 5 - Trang 750-753 - 1983
Comparison of high-pressure liquid chromatography and bioassay for determination of ciprofloxacin in serum and urine Ciprofloxacin was given orally to 10 healthy volunteers for seven consecutive doses of 250 mg every 12 h. Serum and urine samples were collected at distinct times between 0 and 96 h and analyzed both by high-pressure liquid chromatography and by a microbiological assay. The detection limits were 0.006 and 0.03 microgram/ml, respectively. For each method, imprecision coefficients of variation were less than 6.1% at various concentrations in serum and urine. The means +/- standard deviations of the absolute values of the relative differences between the two methods were 9.3 +/- 6.8% (n = 225) for serum samples and 58.5 +/- 50.4% (n = 70) for urine samples. Comparison of the concentrations in serum measured with high-pressure liquid chromatography and bioassay by regression analysis yielded a slope which was not significantly different from 1.0 (99.9% confidence limits: 0.984 less than slope less than 1.035). In urine, however, the bioassay results were markedly higher than the high-pressure liquid chromatography values (1.327 less than slope less than 1.698), which indicates the presence of antimicrobially active metabolites. The cumulative 12-h urinary recovery after the first and seventh doses averaged 30.2 +/- 8.5 and 26.4 +/- 4.6%, respectively, by high-pressure liquid chromatography, whereas with bioassay 38.2 +/- 5.9 and 45.5 +/- 5.9% activity was recovered. Protein binding appeared to be neither concentration nor pH dependent and averaged 21.9 +/- 4.1%.
Antimicrobial Agents and Chemotherapy - Tập 27 Số 3 - Trang 353-356 - 1985
Improved micromethod for mezlocillin quantitation in serum and urine by high-pressure liquid chromatography A rapid, sensitive, and specific method of analysis for mezlocillin in serum and urine by high-pressure liquid chromatography is described. A solid-phase extraction column was used to remove interfering substances from samples before chromatography. Quantitation included the use of an internal standard, nafcillin. Mezlocillin was chromatographed with a phosphate buffer-acetonitrile (73:27) mobile phase and a C-18 reverse-phase column and detected at a wavelength of 220 nm. The assay had a sensitivity of 1.6 micrograms/ml and a linearity of up to 600 micrograms/ml and 16 mg/ml in serum and urine, respectively, with only 0.1 ml of sample. The interday and intraday coefficients of variation for replicate analyses of spiked serum and urine specimens were less than 6.5%.
Antimicrobial Agents and Chemotherapy - Tập 26 Số 5 - Trang 775-777 - 1984
Comparative activities of ciprofloxacin (Bay o 9867), norfloxacin, pipemidic acid, and nalidixic acid An agar dilution method was used to measure the minimal inhibitory concentrations of ciprofloxacin (Bay o 9867), norfloxacin, pipemidic acid, and nalidixic acid against 496 clinical isolates. Ciprofloxacin and norfloxacin were active against all species tested (90% minimal inhibitory concentrations less than or equal to 8 micrograms/ml), although ciprofloxacin was somewhat more active, e.g., against gram-positive cocci. Pipemidic acid and nalidixic acid were active against most of the members of the Enterobacteriaceae, but Klebsiella species and Providencia stuartii were only inhibited by a high concentration of nalidixic acid.
Antimicrobial Agents and Chemotherapy - Tập 24 Số 2 - Trang 302-304 - 1983
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