Clinical and Laboratory Features of Mycobacterium porcinum

Abstract

The rapidly growing mycobacterial species Mycobacterium porcinum was described in 1983 by Tsukamura et al. as a causative agent of submandibular lymphadenitis in swine (23). Tsukamura et al. characterized these strains as being similar to M. fortuitum but differing from this species by being D-mannitol and i-myo-inositol positive, nitrate negative, and succinamidase positive and utilizing benzoate as a sole source of carbon in the presence of ammoniacal nitrogen. Until recently, no isolation of this species had been reported since that report.Bönicke studied isolates previously identified as M. fortuitum and placed them into three subgroups (1). Subgroup A was negative for D-mannitol and i-myo-inositol and now is recognized as M. fortuitum. Subgroup B was positive for D-mannitol but negative for i-myo-inositol and is now recognized as M. peregrinum. Subgroup C was positive for mannitol and inositol, and its taxonomic status has taken much longer to establish and is still evolving. A study by Wallace et al. in 1991 showed this subgroup to consist of two major groups. One group was D-sorbitol positive, had low semiquantitative catalase, and was pipemidic acid resistant, and MICs of cefoxitin (27) and clarithromycin (4) were high for members of the group. ␤-Lactamase patterns on polyacrylamide gels following isoelectric focusing (IEF) had previously showed these isolates to have primarily a single enzyme pattern (28). These isolates were named the M. fortuitum third biovariant complex D-sorbitol-positive group, and ATCC 49403 was chosen as the reference strain (27).Subsequent 16S rRNA gene sequencing showed these isolates to have a unique hypervariable A region (11,19) and an 880-bp sequence of ATCC 49403 to differ by 6 to 15 bp from previously recognized species within the M. fortuitum group (11). To date, three species are recognized within this D-sorbitol-positive group based on 16S rDNA complete sequencing and DNA-DNA homology studies: M. mageritense (7,26), M. houstonense (of which ATCC 49403 is the proposed type strain), and M. brisbanense (16).

Mycobacterium setenseInfection in Humans

“…Likewise, the modifi ed broth dilution method showed that the MIC for imipenem was <4 μg/ml for M. fortuitum (9). However, when a broth dilution method was used, the MIC for imipenem ranged from 0.5 μg/mL to 8 μg/mL in 42 M. porcinum strains (7). Together, these data challenge the susceptibility to imipenem in organisms of the M. fortuitum group.…”

“…We initially suspected that the water was the source of M. setense, as previously suspected for M. conceptionense (6) and reported for M. porcinum (7). However, neither M. setense nor M. setense DNA were detected in the well water in October 2007.…”

Mycobacterium monacense sp. nov.

“…In the last few years, a new scenario has appeared, with many novel rapidly growing species being described that are often responsible for disease in humans (Brown-Elliott & Wallace, 2002). The majority of such novel mycobacteria are not pigmented and have emerged from the splitting of the heterogeneous group known, until a few years ago, as the M. fortuitum complex (Wallace et al, 2004;Adékambi et al, 2006). Here, four strains of a scotochromogenic rapidly growing mycobacterium are described.…”

Mycobacterium Porcinum Peritonitis in a Patient on Continuous Ambulatory Peritoneal Dialysis

“…It is a gram-positive, acid fast, pleomorphic bacillus, negative for pigmentation. 15 Mycobacteria are uncommon causes of peritonitis accounting for 3% of cases. Recent reports, however, suggest that the incidence of NTM peritonitis in patients on CAPD is on the rise.…”

“…al. 15 in their review identified 45 clinical isolates of M. porcinum. The most common site of isolation was wound infections (62%), followed by respiratory (18%), central intravenous catheter related infections (16%) and lymph nodes (2%).…”