What is the mechanism of resistance for streptomycin?
The level of resistance that is seen is moderate (i.e. intermediate susceptibility). Mutations at the site of aminoglycoside attachment may interfere with ribosomal binding. Resistance to streptomycin can occur by this mechanism since this agent binds to a single site on the 30S subunit of the ribosome.
What bacteria is streptomycin resistant?
More recently, mutations in rRNA genes have been found to be associated with in vivo acquired drug resistance in bacterial pathogens, e.g., in Mycobacterium tuberculosis resistant to streptomycin (10); most of the mutations found mapped to the 530 region of 16S rRNA (15, 27).
Is there any resistance to streptomycin?
Streptomycin resistance was the most frequent resistance in the cohort accounting for 82.7% (n = 67) of the resistant Mycobacterium tuberculosis isolates. WGS of 149 clinical isolates identified 13 transmission clusters, including three clusters containing only streptomycin resistant isolates.
Which bacteria is more resistant to antibiotics?
Gram-positive bacteria lack this important layer, which makes Gram-negative bacteria more resistant to antibiotics than Gram-positive ones [5,6,7]. Gram-negative bacteria can cause serious diseases in humans, especially in immuno-compromised individuals.
Why is Staphylococcus resistant to streptomycin?
High-level resistance to streptomycin exhibited by many early clinical isolates of S. aureus was due to chromosomal mutations affecting ribosome affinity. Low-level resistance was usually indicative of small multicopy RC plasmids, such as pS194, which carries the streptomycin adenyltransferase-encoding gene str.
Why is streptomycin so effective?
Streptomycin is an effective antibiotic because its structure is similar to that of the anticodons that would usually bind to the ribosome. Streptomycin is significant because it was the first antibiotic that could treat tuberculosis. Over time, bacteria have become resistant to streptomycin.
What is the target of streptomycin?
Streptomycin irreversibly binds to the 16S rRNA and S12 protein within the bacterial 30S ribosomal subunit. As a result, this agent interferes with the assembly of initiation complex between mRNA and the bacterial ribosome, thereby inhibiting the initiation of protein synthesis.
Why is E. coli resistant to streptomycin?
Abstract. Escherichia coli K-12 carrying the R-factor R1 or R6K is resistant to streptomycin. The resistance is due to R-factor-coded enzymes that metabolize the drug. Streptomycin can be inactivated in two ways, either by adenylylation or by phosphorylation; both reactions require adenosine 5′-triphosphate.
Why is streptomycin not used?
A history of clinically significant hypersensitivity to streptomycin is a contraindication to its use. Clinically significant hypersensitivity to other aminoglycosides may contraindicate the use of streptomycin because of the known cross-sensitivity of patients to drugs in this class.
How does streptomycin resistance affect protein synthesis?
This in turn affects the binding of streptomycin to the ribosome. Some of these mutations lead to streptomycin resistance, but some lead to streptomycin dependence. As mentioned above, streptomycin itself can increase errors in protein synthesis.
What is the concentration of antibiotics in streptomycin?
When appropriate, antibiotics or sucrose was added at the following concentrations: kanamycin, hygromycin, or clarithromycin, 50 μg/ml; gentamicin, 15 μg/ml; sucrose, 7.5% (wt/vol). Mapping of streptomycin resistance-conferring mutations.
What are the mics for streptomycin resistance?
The MICs determined (Table (Table5)5) showed high levels of streptomycin resistance for rpsLmutant strains and for rrsmutation 524G→C (>200 μg/ml). rrsmutations 526C→T, 522 C→T, and 523 A→C conferred an intermediate level of resistance (100 μg/ml).
What is rRNA resistance to streptomycin?
A number of mutations in the rpsLgene encoding the S12 polypeptide generate resistance to streptomycin (10, 36, 46, 47, 49). Rather than being a mere scaffold for ribosomal proteins, the rRNA has important functions and is a main target for drugs interfering with bacterial protein synthesis (12, 26, 33, 42).