“…Most conventional and standard media are suitable for growing this bacterium. Blood agar, chocolate agar, brain–heart infusion agar, Sabouraud dextrose agar, Columbia agar with 5% defibrinated sheep's blood agar [12] and Löwenstein-Jensen medium will all support the growth of most aerobic actinomycetes. Aerobic conditions are recommended to better grow aerobic actinomycetes.…”
Section: Identification Methodsmentioning
confidence: 99%
“…To date, nine species of the genus Tsukamurella have been isolated from human infections: inchonensis, paurometabola, strandjordii, tyrosinosolvens, pulmonis, hongkongensis and sinensis [10] , [11] . Although Tsukamurella serpentis was recently isolated from the oral cavity of two venomous snakes ( Naja atra ) in China, there is no report of human infection by this species after being bitten [12] .…”
Tsukamurella is an aerobic, Gram-positive and nonmotile bacterium. It was first isolated in 1941 from the mycetoma and ovaries of the bedbug. The primary strains were named Corynebacterium paurometabolum and Gordona aurantiaca and are different from the Collins et al., 1988 classification of the new Tsukamurella genus. Human infections with Tsukamurella species are rare because the species is a kind of saprophyte bacterium; however, most information regarding this species comes from case reports. Molecular markers for the identification Tsukamurella include sequencing of 16S rRNA, groEL, rpoB, secA1 and ssrA genes. Given the lack of information on the treatment of Tsukamurella infections, a combination of various antibiotic agents is recommended.
“…Most conventional and standard media are suitable for growing this bacterium. Blood agar, chocolate agar, brain–heart infusion agar, Sabouraud dextrose agar, Columbia agar with 5% defibrinated sheep's blood agar [12] and Löwenstein-Jensen medium will all support the growth of most aerobic actinomycetes. Aerobic conditions are recommended to better grow aerobic actinomycetes.…”
Section: Identification Methodsmentioning
confidence: 99%
“…To date, nine species of the genus Tsukamurella have been isolated from human infections: inchonensis, paurometabola, strandjordii, tyrosinosolvens, pulmonis, hongkongensis and sinensis [10] , [11] . Although Tsukamurella serpentis was recently isolated from the oral cavity of two venomous snakes ( Naja atra ) in China, there is no report of human infection by this species after being bitten [12] .…”
Tsukamurella is an aerobic, Gram-positive and nonmotile bacterium. It was first isolated in 1941 from the mycetoma and ovaries of the bedbug. The primary strains were named Corynebacterium paurometabolum and Gordona aurantiaca and are different from the Collins et al., 1988 classification of the new Tsukamurella genus. Human infections with Tsukamurella species are rare because the species is a kind of saprophyte bacterium; however, most information regarding this species comes from case reports. Molecular markers for the identification Tsukamurella include sequencing of 16S rRNA, groEL, rpoB, secA1 and ssrA genes. Given the lack of information on the treatment of Tsukamurella infections, a combination of various antibiotic agents is recommended.
“…Although MALDI-TOF MS is well-established to be comparable or superior to conventional biochemical tests in terms of accuracy, we are obliged to emphasize that it is still impossible to completely replace DNA sequencing of conserved regions (e.g. 16S rRNA gene sequencing for bacteria and ITS sequencing for fungi) in reference laboratories, due to its current database limitations [ [134] , [135] , [136] , [137] , [138] ] and inability to confirm novel microbial species [ [139] , [140] , [141] , [142] ]. Fig.…”
Mass spectrometry (MS) is a sensitive, specific and versatile analytical technique in the clinical laboratory that has recently undergone rapid development. From initial use in metabolic profiling, it has matured into applications including clinical toxicology assays, target hormone and metabolite quantitation, and more recently, rapid microbial identification and antimicrobial resistance detection by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In this mini-review, we first succinctly outline the basics of clinical mass spectrometry. Examples of hard ionization (electron ionization) and soft ionization (electrospray ionization, MALDI) are presented to demonstrate their clinical applications. Next, a conceptual discourse on mass selection and determination is presented: quadrupole mass filter, time-of-flight mass spectrometer and the Orbitrap; and MS/MS (tandem-in-space, tandem-in-time and data acquisition), illustrated with clinical examples. Current applications in (1) bacterial and fungal identification, antimicrobial susceptibility testing and phylogenetic classification, (2) general unknown urine toxicology screening and expanded new-born metabolic screening and (3) clinical metabolic profiling by gas chromatography are outlined. Finally, major limitations of MS-based techniques, including the technical challenges of matrix effect and isobaric interference; and novel challenges in the post-genomic era, such as protein molecular variants, are critically discussed from the perspective of service laboratories. Computer technology and structural biology have played important roles in the maturation of this field. MS-based techniques have the potential to replace current analytical techniques, and existing expertise and instrument will undergo rapid evolution. Significant automation and adaptation to regulatory requirements are underway. Mass spectrometry is unleashing its potentials in clinical laboratories.
“…In addition to the association with various human infections, Tsukamurella can also be found in different environmental sources and animals 23 , 26 – 29 . We have recently described another novel species, Tsukamurella serpentis , from the oral cavity of Chinese cobras 30 .…”
Although Tsukamurella infections have been increasingly reported in Europe, Asia, America, and Africa, indicating that diseases caused by this group of bacteria are emerging in a global scale, species identification within this genus is difficult in most clinical microbiology laboratories. Recently, we showed that groEL gene sequencing is useful for identification of all existing Tsukamurella species. Nevertheless, PCR sequencing is still considered expensive, time-consuming, and technically demanding, and therefore is yet to be incorporated as a routine identification method in clinical laboratories. Using groEL gene sequencing as the reference method, 60 Tsukamurella isolates were identified as five different Tsukamurella species [T. tyrosinosolvens (n = 31), T. pulmonis (n = 25), T. hongkongensis (n = 2), T. strandjordii (n = 1), and T. sinensis (n = 1)]. The most common source of the patient isolates were the eye (n = 18), sputum (n = 6), and blood (n = 6). None of the 60 isolates were identified correctly to species level by MALDI-TOF MS with the original Bruker database V.6.0.0.0. Using the Bruker database extended with 15 type and reference strains which covered all the currently recognized 11 Tsukamurella species, 59 of the 60 isolates were correctly identified to the species level with score ≥2.0. MALDI-TOF MS should be useful for routine species identification of Tsukamurella in clinical microbiology laboratories after optimization of the database. T. tyrosinosolvens was the most common species observed in patients with Tsukamurella infections and the predominant species associated with ocular infections.
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