Gas-liquid chromatography of cellular fatty acids for identification of staphylococci

Stoakes, Luba; John, Michael; Lannigan, R.; Schieven, Berend C.; Ramos, Michelle Silva; Harley, David; Hussain, Zafar

doi:10.1128/jcm.32.8.1908-1910.1994

Cited by 38 publications

(14 citation statements)

References 22 publications

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“…Methods based on gas-liquid chromatography of staphylococcal cellular fatty acids such as the microbial identification system manufactured by Microbial ID Inc. (Newark, Del.) are labor intensive and show an unacceptable performance for the identification of S. epidermidis (29). In fact, 16 of 36 strains of S. hominis were misidentified as S. epidermidis (16).…”

Section: Discussionmentioning

confidence: 99%

Species-specific and ubiquitous DNA-based assays for rapid identification of Staphylococcus epidermidis

et al. 1996

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Staphylococcus epidermidis is an aerobic gram-positive coccus that is now recognized among the coagulasenegative staphylococci as an etiological agent with an important range of pathogenicity in humans. Several diagnostic kits based on biochemical or immunological reactions can efficiently identify Staphylococcus aureus. However, these tests are often unreliable for the identification of coagulase-negative staphylococcal species including S. epidermidis. Since DNA-based assays for the species-specific identification of S. epidermidis remain unavailable, we have developed such tests in order to improve the accuracy and the rapidity of tests for the diagnosis of S. epidermidis infections. On the basis of the results of hybridization assays with clones randomly selected from an S. epidermidis genomic library, we identified a chromosomal DNA fragment which is specific and 100% ubiquitous for the identification of S. epidermidis. This 705-bp fragment was sequenced and used to design PCR amplification primers. PCR assays with the selected primers were also highly specific and ubiquitous for the identification from bacterial cultures of clinical isolates of S. epidermidis from a variety of anatomic sites. While three strains of S. capitis were misidentified as S. epidermidis with the API Staph-Ident system and 2.5% of the S. epidermidis identifications were inconclusive with the MicroScan Autoscan-4 system, the PCR assay was highly specific and allowed for the correct identification of all 79 S. epidermidis strains tested. The PCR assays developed are simple and can be performed in about 1 h. These DNA-based tests provide novel diagnostic tools for improving the diagnosis of S. epidermidis infections.

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Section: Discussionmentioning

confidence: 99%

Species-specific and ubiquitous DNA-based assays for rapid identification of Staphylococcus epidermidis

et al. 1996

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“…All strains were originally isolated from clinical specimens, and only one strain per patient was included in the study. Isolates were identified by using susceptibility to desferrioxamine (12), conventional biochemical tests, and cellular fatty acid profile analysis as described previously (3,15). Isolates were kept frozen at Ϫ70°C and were subcultured twice before testing.…”

Section: Methodsmentioning

confidence: 99%

Rapid Detection of mecA-Positive andmecA-Negative Coagulase-Negative Staphylococci by an Anti-Penicillin Binding Protein 2a Slide Latex Agglutination Test

Hussain

Stoakes

Garrow

et al. 2000

J. Clin. Microbiol.

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A rapid slide latex agglutination (LA) test, MRSA-Screen (Denka Seiken Co., Niigata, Japan), which detects PBP 2a, was tested for its ability to differentiate between mecA-positive and -negative coagulase-negative staphylococci. A total of 463 isolates from 13 species were included in the study. The mecA gene was detected by PCR, and the oxacillin MIC was determined by the agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The LA test was performed with oxacillininduced isolates. The true-positive and true-negative results were defined on the basis of the presence or the absence of the mecA gene. By PCR, 251 isolates were mecA positive and 212 were mecA negative. The sensitivities, specificities, and positive and negative predictive values for the LA test compared to the NCCLS breakpoint for oxacillin resistance (>0.5 mg/liter) were as follows: for the LA test, 100, 99.5, 99.6, and 100%, respectively; for the NCCLS breakpoint, 100, 60.8, 75.1, and 100%, respectively. One hundred twenty-five mecA-positive isolates were also tested by the LA test without induction of PBP 2a; only 72 (57.6%) gave a positive result and required 3 to 15 min for reaction. With induction, all 251 isolates were positive within 3 min. The LA test was reliable in classifying mecA-negative isolates, but it classified isolates for which the oxacillin MIC was >0.5 mg/liter as oxacillin susceptible. For the reliable detection of oxacillin resistance by the MRSA-Screen in coagulase-negative staphylococci, induction of the mecA gene appears to be necessary.

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“…Previous studies indicated that the agreement between the MIS and the conventional methods for the identification of Staphylococcus species was 87.8%, whereas the overall identification rate with several commercially available identification kits was 85% (22). Furthermore, the fatty acid chromatogram of S. aureus obtained with the MIS is distinct and can be used to separate these strains from other species (22).…”

Section: Fig 2 Rapd Patterns Of the 16mentioning

confidence: 99%

Dissemination of Two Methicillin-Resistant Staphylococcus aureus Clones Exhibiting Negative Staphylase Reactions in Intensive Care Units

Hsueh¹,

Teng

Yang³

et al. 1999

J Clin Microbiol

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From December 1997 to March 1998, 25 methicillin-resistantStaphylococcus aureus (MRSA) isolates exhibiting negative Staphylase (Oxoid Ltd., Basingstoke, England) reactions were identified from various clinical specimens from 13 patients in six intensive care units (ICUs) or in wards following a stay in an ICU at the National Taiwan University Hospital. The characteristics of these isolates have not been previously noted in other MRSA isolates from this hospital. Colonies of all these isolates were grown on Trypticase soy agar supplemented with 5% sheep blood and were nonhemolytic and unpigmented. Seven isolates, initially reported as Staphylococcus haemolyticus (5 isolates) and Staphylococcus epidermidis (2 isolates) by the routine identification scheme and with the Vitek GPI system (bioMerieux Vitek, Inc., Hazelwood, Mo.), were subsequently identified as S. aureus by positive tube coagulase tests, standard biochemical reactions, and characteristic cellular fatty acid chromatograms. The antibiotypes obtained by the E test, coagulase types, restriction fragment length polymorphism profiles of the staphylococcal coagulase gene, and random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates disclosed that two major clones disseminated in the ICUs. Clone 1 (16 isolates) was resistant to clindamycin and was susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ) and was coagulase type II. Clone 2 (eight isolates) was resistant to clindamycin and TMP-SMZ and was coagulase type IV. These two epidemic clones from ICUs are unique and underline the need for caution in identifying MRSA strains with colonial morphologies not of the typical type and with negative Staphylase reactions.

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Gas-liquid chromatography of cellular fatty acids for identification of staphylococci

Cited by 38 publications

References 22 publications

Species-specific and ubiquitous DNA-based assays for rapid identification of Staphylococcus epidermidis

Species-specific and ubiquitous DNA-based assays for rapid identification of Staphylococcus epidermidis

Rapid Detection of mecA-Positive andmecA-Negative Coagulase-Negative Staphylococci by an Anti-Penicillin Binding Protein 2a Slide Latex Agglutination Test

Dissemination of Two Methicillin-Resistant Staphylococcus aureus Clones Exhibiting Negative Staphylase Reactions in Intensive Care Units

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