Degradation of Sulfadiazine by Microbacterium lacus Strain SDZm4, Isolated from Lysimeters Previously Manured with Slurry from Sulfadiazine-Medicated Pigs

Abstract

b Sulfadiazine (SDZ)-degrading bacterial cultures were enriched from the topsoil layer of lysimeters that were formerly treated with manure from pigs medicated with 14 C-labeled SDZ. The loss of about 35% of the applied radioactivity after an incubation period of 3 years was attributed to CO 2 release due to mineralization processes in the lysimeters. Microcosm experiments with moist soil and soil slurries originating from these lysimeters confirmed the presumed mineralization potential, and an SDZ-degrading bacterium was isolated. It was identified as Microbacterium lacus, denoted strain SDZm4. During degradation studies with M. lacus strain SDZm4 using pyrimidine-ring labeled SDZ, SDZ disappeared completely but no 14 CO 2 was released during 10 days of incubation. The entire applied radioactivity (AR) remained in solution and could be assigned to 2-aminopyrimidine. In contrast, for parallel incubations but with phenyl ring-labeled SDZ, 56% of the AR was released as 14 CO 2 , 16% was linked to biomass, and 21% remained as dissolved, not yet identified 14 C. Thus, it was shown that M. lacus extensively mineralized and partly assimilated the phenyl moiety of the SDZ molecule while forming equimolar amounts of 2-aminopyrimidine. This partial degradation might be an important step in the complete mineralization of SDZ by soil microorganisms.

Fate of the antibiotic sulfadiazine in natural soils: Experimental and numerical investigations

“…SDZ biodegradation thus becomes an important and limiting factor for the migration of SDZ in shallow parts of the soil profile. The short half-life that occurred in the lysimeter experiments corresponds well with the SDZ half-lives of 11 to 28 days obtained by Halling-Sørensen (2000) and Tappe et al (2013).…”

“…The first-order degradation was used to represent biotransformation of SDZ and its TPs (Tappe et al, 2013). However, since only one TP, 2-aminopyrimidine, was detected in the field-scale experiments, a set of simultaneously occurring biotransformation pathways was reduced to: i) SDZ into 2-aminopyrimidine, ii) 2-aminopyrimidine into an "unknown" end product, and iii) SDZ into other TPs such as M1, M2, M3, 4-OH-SDZ and N-acetyl-SDZ (Sittig et al, 2012).…”

Dynamics of Soil Bacterial Communities in Response to Repeated Application of Manure Containing Sulfadiazine

“…The enhanced transferability of resistant genes was recently also reported by Jechalke et al [15] in a field experiment using manure from SDZ-treated pigs. However, we cannot exclude that some of the taxa were intrinsically resistant to, or even able to mineralize SDZ as a SDZ degrader identified as Microbacterium lacus was recently isolated from the same Merzenhausen soil [44]. Interestingly, in the present study an OTU affiliated to Leifsonia , which is phylogenetically closely related to Microbacterium was found to be enriched in S100 soils.…”

Biotransformation of tetracycline by a novel bacterial strain Stenotrophomonas maltophilia DT1

“…Different from sulfonamide compounds, whose degradation by pure bacterial cultures [47][48][49] and microbially mediated abiotic processes [50] have been reported, little is known about how microbial processes may transform tetracycline compounds. Several…”