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Automated analysis of 35-S-methionine labeled proteins by SDS-PAGE as a typing method in a suspected cluster of
M Altwegg1, J Lüthy-Hottenstein, M Grehn
1Department of Medical Microbiology, University of Zürich, Switzerland.
Abstract:
During a nine-month period in 1986, we observed five ornithine decarboxylase-negative isolates of Serratia marcescens from four different patients. All isolates were identical in more than 50 biochemical parameters. Four isolates from three hospitalized patients were essentially identical in their susceptibility patterns to 12 antimicrobial agents. Analysis of 35-S-methionine labeled whole cell proteins by SDS-PAGE with the AMBIS system (Automated Microbiology System Inc., San Diego, CA) suggested that only three of these isolates were identical while the fourth hospital strain was more closely related to the isolate of a patient with no contact to the hospital. These results were confirmed by bacteriocin- and serotyping. We conclude that analysis of these protein patterns--which does not require special reagents - was an adequate method for typing S. marcescens.
Insights
This study identified ornithine decarboxylase-negative Serratia marcescens in patients. Protein pattern analysis proved effective for typing these bacterial isolates.
Area of Science:
- Microbiology
- Bacterial Typing
- Clinical Diagnostics
Background:
- Serratia marcescens is an opportunistic pathogen.
- Accurate bacterial identification and typing are crucial for infection control and epidemiological studies.
Observation:
- Five ornithine decarboxylase-negative Serratia marcescens isolates were identified from four patients over nine months.
- Biochemical profiling showed all isolates were identical in over 50 parameters.
- Antimicrobial susceptibility testing revealed near-identical patterns among four isolates from hospitalized patients.
Findings:
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of 35-S-methionine labeled whole-cell proteins indicated that only three of the four hospital isolates were identical.
- The fourth hospital strain showed closer relatedness to an isolate from a non-hospitalized patient.
- Bacteriocin and serotyping confirmed these protein-based typing results.
Implications:
- Protein pattern analysis using SDS-PAGE is a reliable and cost-effective method for typing Serratia marcescens.
- This technique can aid in distinguishing between closely related bacterial strains in clinical settings.
- Understanding strain relatedness is vital for tracking nosocomial infections and transmission pathways.