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Outer membrane protein alterations in Serratia marcescens resistant against aminoglycoside and beta-lactam
Abstract:
Six isolates of Serratia marcescens were recovered sequentially from the respiratory tract of a single patient. The first three isolates were of the 'opaque' (wild-type) colony type and were susceptible to amikacin, cefotaxime, and lamoxactam. The following three isolates were of the small, 'gray' colony variety, significantly less susceptible to the three antibiotics, and revealed three altered outer membrane proteins, as determined with the SDS-PAGE procedure.
Insights
Sequential Serratia marcescens isolates from one patient showed reduced susceptibility to key antibiotics. This change correlated with altered outer membrane proteins, suggesting a mechanism for antibiotic resistance development in respiratory infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Biochemistry
Background:
- Serratia marcescens is an opportunistic pathogen.
- Antibiotic resistance is a growing global health concern.
- Understanding resistance mechanisms is crucial for effective treatment.
Purpose of the Study:
- To investigate the sequential development of antibiotic resistance in Serratia marcescens isolates from a single patient.
- To identify potential molecular changes associated with decreased antibiotic susceptibility.
Main Methods:
- Sequential isolation of Serratia marcescens from patient respiratory tract samples.
- Phenotypic characterization of antibiotic susceptibility (amikacin, cefotaxime, lamoxactam).
- Analysis of outer membrane protein profiles using SDS-PAGE.
Main Results:
- Three initial 'opaque' (wild-type) isolates were susceptible to amikacin, cefotaxime, and lamoxactam.
- Three subsequent 'gray' colony isolates exhibited reduced susceptibility to these antibiotics.
- SDS-PAGE revealed three distinct alterations in outer membrane proteins in the less susceptible isolates.
Conclusions:
- A shift in colony morphology in Serratia marcescens correlated with decreased antibiotic susceptibility.
- Alterations in outer membrane proteins are associated with reduced susceptibility to amikacin, cefotaxime, and lamoxactam.
- This study highlights potential mechanisms of antibiotic resistance acquisition in persistent infections.