Retrospective evaluation of a PCR based assay for the direct detection of methicillin-resistant Staphylococcus aureus in clinical specimen.

We evaluated the performance of a PCR-based dipstick assay used in our routine laboratory for the direct detection of Methicillin resistant Staphylococcus aureus (MRSA). 2941 clinical swab specimens were evaluated. Sensitivity and specificity were 94.1% and 98.3%, respectively. The PCR assay combines low instrumentation costs and minor hands-on-time with reliable results for MRSA identification.

Randomized, double-blind crossover study of vaginal microflora and epithelium in women using a tampon with a "winged" apertured film cover and a commercial tampon with a nonwoven fleece cover.

This study compared the safety of a new tampon with a four-winged apertured film cover over its nonwoven cover to improve leakage performance with that of a commercial tampon with a nonwoven cover only. Healthy women (evaluable, n = 69) were randomized to crossover between test and reference tampons in two consecutive menstrual cycles. Qualitative and quantitative analyses of vaginal cultures were conducted pre-, mid-, and postmenstrually for a broad panel of microorganisms, and colposcopy was performed. Similar to previous studies, prevalence and mean colony counts of the majority of microorganisms generally increased midmenstrually and returned or began to return postmenstrually. In contrast to most previous studies, Lactobacillus species remained at similar levels throughout the cycles with both tampons. Neither tampon was associated with clinically significant microbiological changes or abnormalities or with vaginal/cervical epithelial integrity changes on colposcopy. Microbiological and colposcopic evaluations indicate that the apertured film-covered tampon is safe.

Performance of a matrix-assisted laser desorption ionization-time-of-flight mass spectrometry system for the identification of bacterial isolates in the clinical routine laboratory.

BACKGROUND: Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has emerged as a new tool for the fast and reliable identification of microorganisms. We evaluated the performance of a MALDI-TOF MS-system for the identification of various clinical isolates in the routine microbiology setting. MATERIAL AND METHODS: For the evaluation study a set of 1116 bacterial isolates were collected in the routine microbiology laboratory. Additonally 108 isolates of strain culture collections (ATTC, DSMZ) were utilized. Identification of the bacterial isolates was perfomed with a Microflex LT mass spectrometer in combination with the MALDI-Biotyper 2.0 software (Bruker Daltonik GmbH, Bremen, Germany). The results of the MALDI-TOF MS were compared to phenotypic bacterial identification systems used in our routine laboratory. Discrepancies were resolved by 16 S rDNA-sequencing. RESULTS: Of the 108 reference strains tested, 101 (93.5%) were correctly identified to species level. Overall, 1062 (95.2%) of the 1116 strains collected in the routine laboratory were correctly identified with the MALDI-Biotyper. Accuracy for the identification of Enterobacteriaceae, non-fermenting gram-negative rods, staphylococci, enterococci and streptococci with the MALDI-Biotyper was 95.5%, 79.7%, 99.5%, 100% and 93.7%, respectively. Results were available in 12 minutes for direct smear and in 20 min with an extraction method. CONCLUSIONS: The MALDI-TOF method proves to be a fast and reliable method for the identification of the most important bacterial isolates in the clinical laboratory.

A prospective, randomized, double-blind study of vaginal microflora and epithelium in women using a tampon with an apertured film cover compared with those in women using a commercial tampon with a cover of nonwoven fleece.

Healthy women with normal menstrual cycles were randomly assigned to use either a test tampon during cycle 1 and a reference tampon during cycle 2 or a reference tampon during cycle 1 and a test tampon during cycle 2. Tampons were identical except for their cover materials: apertured film for the test tampon and nonwoven fleece for the reference tampon. Product use was doubly blinded. Qualitative and quantitative analyses of vaginal cultures were done pre-, mid-, and postmenstrually for a broad panel of microorganisms, colposcopy was performed, and diary reports were collected; 101 of 105 enrolled subjects completed the study. Midmenstrual findings for a variety of organisms differed from pre- and postmenstrual observations whether subjects were using test or reference tampons. No statistically significant differences were noted in prevalence or colony counts at premenstrual versus mid- and postmenstrual visits for most microorganisms. Prevalences of Gardnerella and anaerobic gram-negative rods were significantly different between tampons at the premenstrual visit, when unusually low values were observed for the test and reference tampons, respectively. None of the changes or differences in microflora were considered to be clinically significant. It is noteworthy, however, that declines in the prevalence and abundance of Lactobacillus during the menstrual periods were less pronounced during the use of both test and reference tampons than those reported from previous studies. Colposcopy showed no abnormal findings with either tampon and no changes in vaginal or cervical epithelial integrity. Thus, all evidence from both microbiological and colposcopic evaluations indicates that the apertured film cover of the test tampon is as safe as the nonwoven cover of the reference tampon.

Two-center collaborative evaluation of performance of the BD phoenix automated microbiology system for identification and antimicrobial susceptibility testing of gram-negative bacteria.

The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, MD) was assessed for identification (ID) and antimicrobial susceptibility testing (AST) of the majority of clinically encountered bacterial isolates in a European collaborative two-center trial. A total of 494 bacterial isolates including various species of the Enterobacteriaceae and 110 nonfermentative gram-negative bacteria were investigated: of these, 385 were single patient isolates, and 109 were challenge strains tested at one center. The performance of the Phoenix extended-spectrum beta-lactamase (ESBL) test was also evaluated for 203 strains of Escherichia coli, Klebsiella pneumoniae, and Klebsiella oxytoca included in the study. Forty-two antimicrobial drugs were tested, including members of the following drug classes: aminoglycosides, beta-lactam antibiotics, beta-lactam/beta-lactamase inhibitors, carbapenems, cephems, monobactams, folate antagonists, quinolones, and others. Phoenix system ID results were compared to those of the laboratories' routine ID systems (API 20E and API CHE, ATB ID32E, ID32GN, and VITEK 2 [bioMérieux, Marcy l'Etoile, France]); Phoenix AST results were compared to those of frozen standard broth microdilution (SBM) panels according to NCCLS (now CLSI) guidelines (NCCLS document M100-S9, approved standard M7-A4). Discrepant results were repeated in duplicate. Concordant IDs of 98.4 and 99.1% were observed for the Enterobacteriaceae and the nonfermentative group, respectively. For AST results, the overall essential agreement was 94.2%; the category agreement was 97.3%; and the very major error rate, major error rate, and minor error rate were 1.6, 0.6, and 1.9%, respectively. In terms of ESBL detection, Phoenix results were 98.5% concordant with those of the reference system, with 98.0% sensitivity and 98.7% specificity. In conclusion, the Phoenix ID results showed high agreement with results of the systems to which they were being compared: the AST performance was highly equivalent to that of the SBM reference method, and the system proved to be very accurate for the detection of ESBL producers.

Usefulness of the GenoType MTBC assay for differentiating species of the Mycobacterium tuberculosis complex in cultures obtained from clinical specimens.

A novel DNA strip assay, GenoType MTBC, was evaluated for differentiation of Mycobacterium tuberculosis complex species from 77 positive liquid cultures in clinical practice. Species identification (M. tuberculosis [71 strains], Mycobacterium bovis subsp. bovis [5 strains], and Mycobacterium africanum subtype I [1 strain]) results were identical to conventional results. The sensitivity was slightly higher for this test than for the AccuProbe assay.

Two-center collaborative evaluation of the performance of the BD Phoenix automated microbiology system for identification and antimicrobial susceptibility testing of Enterococcus spp. and Staphylococcus spp.

The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.) was assessed for identification (ID) and antimicrobial susceptibility testing (AST) for the majority of clinically encountered bacterial isolates in a European collaborative two-center trial. A total of 469 bacterial isolates of the genera Staphylococcus (275 isolates), Enterococcus (179 isolates), and Streptococcus (15 isolates, for ID only) were investigated; of these, 367 were single patient isolates, and 102 were challenge strains tested at one center. Sixty-four antimicrobial drugs were tested, including the following drug classes: aminoglycosides, beta-lactam antibiotics, beta-lactam-beta-lactamase inhibitors, carbapenems, cephems, folate antagonists, quinolones, glycopeptides, macrolides-lincosamides-streptogramin B (MLS), and others. Phoenix ID results were compared to those of the laboratories' routine ID systems (API 32 Staph, API 32 Strep, and VITEK 2 [bioMérieux, Marcy l'Etoile, France]); Phoenix AST results were compared to those of frozen standard broth microdilution (SBM) panels according to NCCLS guidelines (NCCLS document M 100-S 9, approved standard M 7-A 4). Discrepant results were repeated in duplicate. Concordant IDs of 97.1, 98.9, and 100% were observed for staphylococci, enterococci, and streptococci, respectively. For AST results the overall essential agreement was 93.3%; the category agreement was 97.3%; and the very major error rate, major error rate, and minor error rate were 1.2, 1.9, and 1.3%, respectively. In conclusion, the Phoenix ID results showed high agreement with results of the systems to which they were being compared; the AST performance was highly equivalent to that of the SBM reference method.