The Mycobacterium fortuitum third biovariant complex (sorbitol-negative and sorbitol-positive) contains unnamed taxa first characterized in 1991. These organisms can cause respiratory infections, a spectrum of soft tissue and skeletal infections, bacteraemia and disseminated disease. To evaluate this group of organisms, clinical reference isolates and the type strains of M. fortuitum third biovariant complex sorbitol-negative (n=21), M. fortuitum third biovariant complex sorbitol-positive (n=3), M. fortuitum (n=3), Mycobacterium peregrinum (pipemidic acid-susceptible) (n=1), Mycobacterium porcinum (n=1), Mycobacterium senegalense (n=2) and Mycobacterium septicum (n=1) were characterized by using conventional phenotypic (morphological, physiological and antimicrobial susceptibilities), chemotaxonomic (HPLC and cellular fatty acids) and genotypic [RFLP of the rRNA gene (ribotyping), PCR-RFLP of a 439 bp segment of the 65 kDa hsp gene (PCR restriction analysis) and 16S rRNA gene sequence] analysis, DNA G+C content and DNA–DNA relatedness analyses. The results of these studies indicated that the strains comprised M. porcinum (n=13), M. septicum (n=1) and four novel closely related genetic groups within the M. fortuitum third biovariant complex: Mycobacterium boenickei sp. nov. (n=6), Mycobacterium houstonense sp. nov. (n=2), Mycobacterium neworleansense sp. nov. (n=1) and Mycobacterium brisbanense sp. nov. (n=1), with type strains ATCC 49935T (=W5998T=DSM 44677T), ATCC 49403T (=W5198T=DSM 44676T) ATCC 49404T (=W6705T=DSM 44679T) and ATCC 49938T (=W6743T=DSM 44680T), respectively.

Four strains of novel, rapidly growing, acid–alcohol-fast-staining bacteria were characterized with a polyphasic approach. Isolates were received by the Centers for Disease Control and Prevention from domestic health department laboratories for reference testing as unidentifiable, clinical mycobacteria. Bacteria were rod-shaped and produced non-pigmented (white to beige), non-photochromogenic, smooth or wrinkled-rough colonies on Middlebrook 7H10 and 7H11 media at 33 °C. The smooth and wrinkled colony forms were representative of two species with 68·0 and 72·0 mol% DNA G+C content. The cell wall contained meso-diaminopimelic acid and mycolic acids. Species were characterized by cellular fatty acids of C10 : 0, C14 : 0, C16 : 1ω9t, C16 : 0, C18 : 1ω9c and 10-methyl C18 : 0 (tuberculostearic acid). HPLC analysis of mycolic acids produced a novel late-emerging, genus-specific mycolate pattern. TLC analysis demonstrated a novel α +-mycolate. Species were 98·9 % similar by comparison of 16S rRNA gene sequences; however, the DNA–DNA association was <28 %. Phylogenetic analysis of 16S rRNA gene sequences demonstrated an association with Rhodococcus equi, although a DNA–DNA relatedness value of 2 % did not support a close relationship. PCR analysis of a proposed, selected actinomycete-specific 439 bp fragment of the 65 kDa heat-shock protein was negative for three of the four isolates. The creation of Segniliparaceae fam. nov. is proposed to encompass the genus Segniliparus gen. nov., including two novel species, the type species Segniliparus rotundus sp. nov. and Segniliparus rugosus sp. nov., with the respective type strains CDC 1076T (=ATCC BAA-972T=CIP 108378T) and CDC 945T (=ATCC BAA-974T=CIP 108380T).

NoteMycobacterium shottsii sp. nov., a slowly growing species isolated from Chesapeake Bay striped bass (Morone saxatilis)

Mycobacterium abscessus and Mycobacterium chelonae are two closely related species that are often not distinguished by clinical laboratories despite the fact they cause diseases requiring different treatment regimens. Multilocus enzyme electrophoresis, PCR-restriction fragment length polymorphism analysis of the 65-kDa heat shock protein gene, biochemical tests, and high-performance liquid chromatography of mycolic acids were used to identify 75 isolates as either M. abscessus or M. chelonae that were originally submitted for drug susceptibility testing. Only 36 of these isolates were submitted with an identification at the species level. Using the above methods, 46 of the isolates were found to be M. abscessus and 29 were identified as M. chelonae. Eight isolates originally submitted as M. chelonae were identified as M. abscessus, and one isolate submitted as M. abscessus was found to be M. chelonae. The four identification methods were in agreement in identifying 74 of the 75 isolates. In drug susceptibility testing, all isolates of M. abscessus exhibited resistance to tobramycin (MIC of 8 to >16 g/ml), while all isolates of M. chelonae were susceptible to this drug (MIC of <4 g/ml). The results suggest that once an identification method is selected, clinical laboratories should be able to easily identify isolates of M. abscessus and M. chelonae.Mycobacterium abscessus and Mycobacterium chelonae are two species of rapidly growing mycobacteria frequently associated with nosocomial outbreaks and pseudo-outbreaks (1,11,24). Widespread outbreaks of postinjection abscesses have occurred due to medications contaminated with M. abscessus (6,22). Contamination of hospital equipment and medications can generally be traced to the ubiquitous presence of these organisms in tap water and their resistance to commonly used disinfectants (24).It is clinically important to correctly identify these organisms since they cause infections requiring different treatment regimens (R. J. Wallace, Jr., B. A. Brown, D. E. Griffith, Letter, Pediatr. Infect. Dis. J. 16:829, 1997). Prior to 1992, M. abscessus was considered a subspecies of M. chelonae. Though Kusunoki and Ezaki (10) firmly established through DNA hybridization that these organisms are separate species, they are nearly indistinguishable phenotypically. Only two biochemical tests, those for sodium chloride tolerance and utilization of citrate, are useful for identifying these organisms at the species level (17), but these tests may take up to 4 weeks to complete (5). Identification of rapidly growing species using high-performance liquid chromatography (HPLC) of mycolic acids has been limited with M. abscessus and M. chelonae because they produce very similar mycolic acid patterns (2). Recently, PCRbased methods targeting polymorphic regions of the 65-kDa heat shock protein (HSP) gene have been used successfully to identify isolates of M. abscessus and M. chelonae (8, 15; A. R. Lakshmy, N. Siddiqi, M. Shamim, M. Deb, G. Mehta, and S. E. Hasnain, Letter, Emerg. Infect. Dis. 6...

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Gordonia species have been recognized as pathogens in immunocompromised and immunocompetent patients. We report the first case of bacteremia due to Gordonia bronchialis in a diabetic patient with a sequestrated lung. Species identification was confirmed with mycolic acid analysis by high-performance liquid chromatography and sequencing of the 16S rRNA gene.A 58-year-old woman with recently discovered diabetes mellitus, long-standing spondylolisthesis, and asthma presented with acute exacerbation of low back pain after an exercise session. Breathlessness, fever, and chills accompanied the pain. The patient had been treated for a pleural effusion and a loculated lung cyst with drainage 15 and 5 years previously, respectively. On physical examination, the patient was febrile with a reduced ability to raise and straighten her right leg and diminished deep tendon reflexes of the right lower limb. The patient's white cell count was elevated, at 15 ϫ 10 9 /liter, with a predominance of polymorphs (86%). Chest X-rays showed pneumonic-type lung consolidation, and consequently the patient was treated with ceftriaxone and clarithromycin for community-acquired pneumonia. Computer-assisted tomography of the thorax suggested a sequestrated lung.Subsequent magnetic resonance imaging of the lumbosacral spine showed a 5-mm air pocket with enhancement surrounding the lesion from L4 to S1. The antimicrobials with which the patient was treated were changed to cloxacillin for osteomyelitis and ceftazidime for possible infection with Burkholderia pseudomallei, which is endemic in the southeast Asia region. On the fifth day, blood cultures taken during admission and incubated in Bactec 9000 (Becton Dickinson, Cockeysville, Md.) were positive for growth. Haemophilus aphrophilus was isolated upon subculture on a blood agar plate and identified by using XV disks and the API NH (bioMérieux, Marcyl'Etoile, France) system. The isolate was found to be susceptible to ceftriaxone by the disk diffusion method. A transthoracic echocardiogram was normal. However, the patient's health did not improve and her neurological status deteriorated, with a loss of ankle reflex. A repeat scan of the lumbar spine demonstrated a subcortical mass at L3 to L4 with a left paravertebral abscess extending inferiorly to the gluteal region. Reincubation of the original blood agar plate for an additional 5 days revealed the presence of a second organism, which formed translucent, nonhemolytic, dry, wrinkled colonies within 24 h; these colonies became opaque, rough, and salmon colored at 72 h. Growth and pigmentation were demonstrated at 35°C with ambient air on Trypticase soy agar with sheep blood, chocolate agar, and brain heart infusion agar. The isolate was a beaded gram-positive bacillus which was weakly acid-fast. The microscopic appearance of the growth on a water agar plate showed symmetra and no aerial hyphae. Tests for lysozyme, casein, tyrosine, and xanthine hydrolysis were negative, while tests for urease and nitrate were positive after 48 h and a test fo...