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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Identification and characterization of quaternary ammonium compound resistant staphylococci from the food industry
E Heir1, G Sundheim, A L Holck
1MATFORSK, Norwegian Food Research Institute, As, Norway. even.heir@folkehelsa.no
Abstract:
The distribution of known genes conferring resistance to quaternary ammonium compounds (QACs) among different species of staphylococci isolated from the food industry was investigated. Twenty-four isolates hosting one of the genes qacA/qacB, smr, qacG or qacH, were subjected to species identification. Species determination was performed by biochemical analyses (API STAPH), comparative 16S rDNA sequence analysis and tDNA intergenic spacer length polymorphism analysis. Good correlation was obtained between the different methods. The isolates belonged to six different species of coagulase-negative Staphylococcus. The most commonly found species were Staphylococcus epidermidis and Staphylococcus saprophyticus. The results also indicated the possible spread of specific isolates of staphylococci which may reflect the dominance of certain strains in environments were QACs are used on a regular basis. The isolates were further characterized by the resistance phenotype to antimicrobial agents including antibiotics and disinfectants. Resistance to ampicillin, penicillin G and dyes was prevalent in strains harbouring the qacA or qacB genes, features also common among clinical staphylococci containing qacA/qacB. One QAC resistant strain harbouring the smr gene showed resistance to ampicillin, penicillin, tetracycline, erythromycin and trimethoprim. No enterotoxin production was detected among the QAC resistant strains.
Insights
Quaternary ammonium compound (QAC) resistance genes were found in six Staphylococcus species from the food industry. Staphylococcus epidermidis and S. saprophyticus were most common, with some strains showing co-resistance to antibiotics.
Area of Science:
- Microbiology
- Food Safety
- Antimicrobial Resistance
Background:
- Quaternary ammonium compounds (QACs) are widely used disinfectants.
- Understanding QAC resistance in foodborne bacteria is crucial for public health.
- Staphylococci are common contaminants in food processing environments.
Purpose of the Study:
- To investigate the distribution of QAC resistance genes in staphylococci from the food industry.
- To identify the Staphylococcus species carrying these resistance genes.
- To characterize the antimicrobial resistance phenotypes of these isolates.
Main Methods:
- Species identification using API STAPH, 16S rDNA sequencing, and tDNA intergenic spacer length polymorphism.
- Detection of qacA/qacB, smr, qacG, and qacH genes.
- Antimicrobial susceptibility testing for antibiotics and disinfectants.
Main Results:
- Twenty-four QAC-resistant staphylococcal isolates were identified, belonging to six species.
- Staphylococcus epidermidis and Staphylococcus saprophyticus were the most prevalent species.
- Strains with qacA/qacB genes often showed resistance to ampicillin, penicillin G, and dyes; one smr-carrying strain was multidrug-resistant.
Conclusions:
- Specific Staphylococcus species, particularly S. epidermidis and S. saprophyticus, harbor QAC resistance genes in food industry settings.
- The co-occurrence of QAC and antibiotic resistance suggests potential for cross-selection and spread of resistance.
- Monitoring QAC resistance in foodborne staphylococci is important for effective disinfection and control strategies.
