Polyphasic Characterization Reveals that the Human Pathogen Mycobacterium peregrinum Type II Belongs to the Bovine Pathogen Species Mycobacterium senegalense

Abstract

Mycobacterium peregrinum consists of two taxa: types I and II. We evaluated 43 clinical type II strains from throughout the United States. They were responsible for soft-tissue and bone infections, catheter-related infections, and possible pneumonitis. By carbohydrate utilization, they were indistinguishable from type I strains, being D-mannitol and trehalose positive. However, they had a distinct susceptibility pattern that included intermediate ciprofloxacin MICs but low clarithromycin and doxycycline MICs of <1 g/ml. These features were also shared by reference isolates of Mycobacterium senegalense from African bovine cases of "farcy." By 16S rRNA gene sequencing, the type II isolates shared 100% sequence identity with M. senegalense. Partial sequencing of the type II hsp65 gene (441 bp) revealed four sequevars showing >98.4% identity with each other and >98.6% identity with the sequence of five bovine strains of M. senegalense. There was <97.1% identity with M. peregrinum type I isolates and other Mycobacterium fortuitum group species. Sequencing of additional gene targets including the 16S-23S rDNA internal transcribed spacer region and the rpoB gene (partial sequence) revealed a similar phylogenetic grouping. DNA-DNA hybridization showed 76 to 99% relatedness between the bovine and human strains. These studies demonstrate that type II isolates are not isolates of M. peregrinum but represent human strains of M. senegalense. This study is the first to demonstrate this species as a human pathogen. Representative human M. senegalense strains include ATCC 35755 and newly submitted strains ATCC BAA-849, ATCC BAA-850, and ATCC BAA-851.

Mycobacterium senegalense Tissue Infection in a Child After Fish Tank Exposure

“…Susceptibility testing was performed by E-test using the minimum inhibitory concentration (MIC) breakpoints from the Clinical and Laboratory Standards Institute guidelines for the Mycobacterium fortuitum complex because no established guidelines are available specifically for M senegalense (7). In vitro, the organism was susceptible to amikacin (MIC 0.5 µg/mL), clarithromycin (MIC 0.5 µg/mL), ciprofloxacin (MIC 0.25 µg/mL), doxycycline (MIC 0.25 µg/mL), cefoxitin (MIC 8 µg/mL), imipenem (MIC 2 µg/mL) and trimethoprim/ sulfamethoxazole (MIC 0.5/8.5 µg/mL), which are consistent with previously published results (3,8).…”

“…Sequences obtained were compared with a qualitycontrolled sequence database of Mycobacterium type strains and other published strains in the Genbank database (National Institutes of Health, USA) (6). Using a combination of 16S gene sequencing and biochemical testing results (Table 1), the patient's isolate was identified as M senegalense (3,6).…”

Mycobacterium avium in the Postgenomic Era

“…With more access to sequencing technology, some laboratories perform hsp65 gene sequencing in the same manner as that done for 16S rRNA gene sequencing (170). The use of this target as an epidemiological tool for closely related mycobacteria, including MAC organisms, has been investigated (72,86,190,288,289,303). Single SNPs in this region exist among various subsets of M. avium subsp.…”

Antimicrobial Susceptibility Testing, Drug Resistance Mechanisms, and Therapy of Infections with Nontuberculous Mycobacteria

“…This includes accepted pathogenic species such as M. mageritense, M. porcinum, M. mucogenicum, and M. senegalense (54,170,412,414,416,423). Thus, currently, MIC standards that apply to the commonly encountered RGM have also been applied to other less frequently recovered RGM species until more data prove these standards to be nonapplicable.…”