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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Antibiotic resistance, putative virulence factors and curli fimbrination among Cronobacter species
O A Odeyemi1, N Abdullah Sani2
1Aquaculture Microbiology Laboratory, Ecology and Biodiversity Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Launceston, Australia; Food Safety, Security and Quality Research Group, Centre for Biotechnology and Functional Food, Faculty of Science and Technology, National University of Malaysia (UKM), Bangi, 43600, Selangor, Malaysia.
Abstract:
This study aimed to investigate antibiotic resistance and putative virulence factors among Cronobacter sakazakii isolated from powdered infant formula and other sources. The following 9 cultures (CR1-9) were collected from our culture collection: C. sakazakii and 3 Cronobacter species: C. sakazakii ATCC® 29544™, C. muytjensii ATCC® 51329™, C. turicensis E866 were used in this study. Isolates were subjected to antibiotic susceptibility and the following virulence factors (protease, DNase, haemolysin, gelatinase, motility and biofilm formation) using phenotypic methods. All the bacteria were able to form biofilm on agar at 37 °C and were resistant to ampicillin, erythromycin, fosfomycin and sulphamethoxazole. It was observed from this study that tested strains formed weak and strong biofilm with violet dry and rough (rdar), brown dry and rough (bdar), red mucoid and smooth (rmas) colony morphotypes on Congo red agar. Rdar expresses curli and fimbriae, while bdar expresses curli. Both biofilm colony morphotypes are commonly found in Enterobacteriaceae including Salmonella species. This study also reveals a new colony morphotypes in Cronobacter species. Conclusively, there was correlation between putative virulence factors and antibiotic resistance among the tested bacteria. Further study on virulence and antibiotic resistance genes is hereby encouraged.
Insights
Cronobacter sakazakii, a pathogen found in infant formula, exhibits antibiotic resistance and forms biofilms. This study links these traits to virulence factors, highlighting the need for further genetic investigation.
Area of Science:
- Microbiology
- Food Safety
- Bacterial Pathogenesis
Background:
- Cronobacter sakazakii is an opportunistic pathogen frequently isolated from powdered infant formula.
- Understanding its antibiotic resistance and virulence factors is crucial for public health and food safety.
Purpose of the Study:
- To investigate antibiotic resistance and virulence factors in Cronobacter sakazakii and related species.
- To correlate phenotypic traits with antibiotic resistance patterns.
Main Methods:
- Antibiotic susceptibility testing was performed on 9 Cronobacter isolates.
- Virulence factors including protease, DNase, haemolysin, gelatinase, motility, and biofilm formation were assessed using phenotypic methods.
- Colony morphotypes on Congo red agar were analyzed.
Main Results:
- All tested Cronobacter strains formed biofilms at 37°C and showed resistance to ampicillin, erythromycin, fosfomycin, and sulphamethoxazole.
- Distinct colony morphotypes (rdar, bdar, rmas) were observed, with rdar and bdar expressing curli and fimbriae.
- New colony morphotypes were identified in Cronobacter species.
Conclusions:
- A correlation exists between putative virulence factors and antibiotic resistance in the tested Cronobacter species.
- Further research into the genetic basis of virulence and antibiotic resistance is recommended.
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