Screening for Streptomycin Resistance-Conferring Mutations in Mycobacterium tuberculosis Clinical Isolates from Poland

Abstract

Currently, mutations in three genes, namely rrs, rpsL, and gidB, encoding 16S rRNA, ribosomal protein S12, and 16S rRNA-specific methyltransferase, respectively, are considered to be involved in conferring resistance to streptomycin (STR) in Mycobacterium tuberculosis. The aim of this study was to investigate the spectrum and frequency of these mutations in M. tuberculosis clinical isolates, both resistant and susceptible to STR. Sixty-four M. tuberculosis isolates recovered from as many TB patients from Poland in 2004 were included in the study. Within the sample were 50 multidrug-resistant (32 STR-resistant and 18 STR-susceptible) and 14 pan-susceptible isolates. Preliminary testing for STR resistance was performed with the 1% proportion method. The MICs of STR were determined by the Etest method. Mutation profiling was carried out by amplifying and sequencing the entire rrs, rpsL, and gidB genes. Non-synonymous mutations in either rrs or rpsL gene were detected in 23 (71.9%) of the STR-resistant and none of the STR-susceptible isolates. Mutations in the gidB gene were distributed among 12 (37.5%) STR-resistant and 13 (40.6%) STR-susceptible isolates. Four (12.5%) STR-resistant isolates were wild-type at all three loci examined. None of the rrs, rpsL or gidB mutations could be linked to low, intermediate or high level of STR resistance. In accordance with previous findings, the gidB 47T→G (L16R) mutation was associated with the Latin American-Mediterranean genotype family, whereas 276A→C (E92D) and 615A→G (A205A) mutations of the gidB gene were associated with the Beijing lineage. The study underlines the usefulness of rrs and rpsL mutations as molecular markers for STR resistance yet not indicative of its level. The gidB polymorphisms can serve as phylogenetic markers.

Frequency of rrs and rpsL mutations in streptomycin-resistant Mycobacterium tuberculosis isolates from Iranian patients

“…Interestingly, the majority of SM-resistant isolates in this study were identified either as MDR or showed resistance to more than one drug. Therefore, resistance to SM could be a diagnostic marker for polydrug resistance and MDR as described previously [3,8]. Double mutation both at rrs and rpsL genes has rarely been reported [3,28].…”

“…Nevertheless, high rates of SM resistance and the risk of toxicity led to a gradual decline in the use of SM. However, SM continues to be an integral part of chemotherapy for TB either in combination therapy or as the first-line agent for cases still susceptible to aminoglycosides [8].…”

Genetic Patterns of rpsL and rrs Genes in Clinical Isolates of Mycobacterium tuberculosis, Isfahan‚ Iran

“…According to previous studies‚ mutations in rpsL gene were likely to be associated with a high-level of STR resistance, whereas mutations in rrs gene were shown to confer to an intermediate-level, and in gidB gene a low-level of STR resistance [11,17,20,7,35,[38][39][40]. Mutations in rpsL, rrs and gidB genes were found in circa 70% of M. tuberculosis isolates that were resistant to STR [21,23].…”

“…Mutations in rpsL, rrs and gidB genes were found in circa 70% of M. tuberculosis isolates that were resistant to STR [21,23]. In the research investigating the three-gene panel (rrs, rpsL, and gidB genes), the proportions of STR-resistant isolates with wild-type alleles at all three loci were almost similar, i.e 11.8% in Korea [41], 12.5% in Sierra Leone [42], 6.9% in Vietnam [27], 22% in Brazil [30] and 12.5% in Poland [7]. The portions were much lower than all studies cited above.…”

“…Two years after taking STR‚ in the same decade‚ M. tuberculosis showed resistance to STR due to the drug's unique use and monotherapeutic application [4][5][6]. The resistance together with the drug's strong adverse effects, such as ototoxicity, nephrotoxicity, fetal auditory toxicity and neuromuscular paralysis‚ resulted in declines in its prescription in recent years [7,8]. Nevertheless, due to increases in MDR-TB strains worldwide‚ STR is still considered an integral component of TB treatment regimens.…”