Comparison of phenotypic methods and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry for the identification of aero-tolerant Actinomyces spp. isolated from soft-tissue infections

Ng, Lily Siew Yong; Sim, Janet; Eng, Li Ching; Menon, Sanjay; Tan, Thean Yen

doi:10.1007/s10096-011-1496-3

Cited by 42 publications

(29 citation statements)

References 9 publications

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“…Our results support previous findings that Actinomyces species can be reliably identified using MALDI-TOF MS (10)(11)(12), with all 12 of our tested isolates identified to the species level, as confirmed by molecular testing. Five isolates were correctly identified to the species level by MALDI-TOF MS despite identification scores only reaching genus-level confidence (ie, a p score of Ͻ2.0).…”

Section: Discussionsupporting

confidence: 91%

“…Actinomyces species which are isolated from breast abscess samples may therefore be presumptively identified in the laboratory as diphtheroids based on their morphology and reported as diphtheroids of doubtful or uncertain significance. However, laboratories are increasingly adopting new methods of identification, such as MALDI-TOF MS (13), which allow rapid and increasingly reliable identification of this problematic group of organisms (10)(11)(12). Indeed, most of the cases in Lothian were identified after 2012, which is shortly after our laboratory started using MALDI-TOF MS. With 10 cases diagnosed in 2 years of using MALDI-TOF MS compared to 2 cases over 7 years without MALDI-TOF MS, it is clear that ease of identification is a major factor in the increased recognition of Actinomyces breast infections in our clinical setting.…”

Section: Discussionmentioning

confidence: 99%

“…Subsequently, there is a risk that cultures of Actinomyces species are simply identified morphologically as diphtheroids and dismissed as skin commensals, even when grown from an abscess sample. However, new methods of identification, such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), allow rapid and reliable identification of many bacteria, including Actinomyceslike organisms (10)(11)(12). MALDI-TOF MS and similar technologies are increasingly being adopted by routine diagnostic laboratories worldwide (13).…”

mentioning

confidence: 99%

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Actinomyces species isolated from breast infections

Bing¹,

Loh²,

Helgason³

et al. 2014

European Journal of Surgical Oncology

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Actinomycosis is a chronic infection caused by Actinomyces species characterized by abscess formation, tissue fibrosis, and draining sinuses. The spectrum of infections caused by Actinomyces species ranges from classical invasive actinomycosis to a less invasive form of superficial skin and soft tissue infection. We present a review detailing all Actinomyces species isolated from breast infections in NHS Lothian between 2005 and 2013, Actinomyces species isolated from breast infections referred to the United Kingdom Anaerobe Reference Unit between 1988 and 2014, and cases describing Actinomyces breast infections published in the medical literature since 1994. Actinomyces species are fastidious organisms which can be difficult to identify and are likely to be underascertained as a cause of breast infections. Due to improved diagnostic methods, they are increasingly associated with chronic, recurrent breast infections and may play a more significant role in these infections than has previously been appreciated.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Actinomyces species isolated from breast infections

Bing¹,

Loh²,

Helgason³

et al. 2014

European Journal of Surgical Oncology

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“…Identification by MALDI-TOF MS has been analyzed for single genera of GPR, such as Corynebacterium (13)(14)(15), Actinomyces (16), Nocardia (17), Listeria (18), anaerobic GPR (19), and difficult-to-identify GPR (20,21). These studies were mostly done using the Bruker MALDI Biotyper system and indicated that sample preparation by the direct transfer procedure without additional modification is not sufficient for accurate identification of GPR but that a chemical extraction method is required.…”

mentioning

confidence: 99%

Evaluation of the Bruker MALDI Biotyper for Identification of Gram-Positive Rods: Development of a Diagnostic Algorithm for the Clinical Laboratory

et al. 2014

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Reported matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identification rates of Gram-positive rods (GPR) are low compared to identification rates of Gram-positive cocci. In this study, three sample preparation methods were compared for MALDI-TOF MS identification of 190 well-characterized GPR strains: direct transfer, direct transfer-formic acid preparation, and ethanol-formic acid extraction. Using the interpretation criteria recommended by the manufacturer, identification rates were significantly higher for direct transfer-formic acid preparation and ethanol-formic acid extraction than for direct transfer. Reducing the species cutoff from 2.0 to 1.7 significantly increased species identification rates. In a subsequent prospective study, 215 clinical GPR isolates were analyzed by MALDI-TOF MS, and the results were compared to those for identification using conventional methods, with discrepancies being resolved by 16S rRNA and rpoB gene analysis. Using the direct transfer-formic acid preparation and a species cutoff of 1.7, congruencies on the genus and species levels of 87.4% and 79.1%, respectively, were achieved. In addition, the rate of nonidentified isolates dropped from 12.1% to 5.6% when using an extended database, i.e., the Bruker database amended by reference spectra of the 190 GPR of the retrospective study. Our data demonstrate three ways to improve GPR identification by the Bruker MALDI Biotyper, (i) optimize sample preparation using formic acid, (ii) reduce cutoff scores for species identification, and (iii) expand the database. Based on our results, we suggest an identification algorithm for the clinical laboratory combining MALDI-TOF MS with nucleic acid sequencing.

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“…Several recent publications demonstrate the ability of MALDI-TOF MS to correctly and rapidly identify Actinomyces spp. (15,16,17,18). MALDI-TOF MS may be considered an alternative method for routine identification, provided the database is up to date.…”

mentioning

confidence: 99%

Actinomyces urogenitalis Bacteremia and Tubo-Ovarian Abscess after an In Vitro Fertilization (IVF) Procedure

Hoecke

Beuckelaers

et al. 2013

J Clin Microbiol

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We describe the first case of bacteremia due to Actinomyces urogenitalis. Bacteremia was secondary to a tubo-ovarian abscess following transvaginal oocyte retrieval. Identification was established by matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and confirmed by 16S rRNA gene sequencing. A. urogenitalis should be considered as a potential causative agent of infection after gynecological procedures. CASE REPORT

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Comparison of phenotypic methods and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry for the identification of aero-tolerant Actinomyces spp. isolated from soft-tissue infections

Cited by 42 publications

References 9 publications

Actinomyces species isolated from breast infections

Actinomyces species isolated from breast infections

Evaluation of the Bruker MALDI Biotyper for Identification of Gram-Positive Rods: Development of a Diagnostic Algorithm for the Clinical Laboratory

Actinomyces urogenitalis Bacteremia and Tubo-Ovarian Abscess after an In Vitro Fertilization (IVF) Procedure

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