First report of contamination of dried spices and herbs with desiccation-tolerant, biofilm-forming A. baumannii

Abstract

The spread of antibiotic-resistant bacteria through the food chain is an issue of growing concern for public health. Antibiotic-resistant strains of Acinetobacter baumannii are commonly identified in nosocomial infections and have been linked to the highest mortality rates. However, A. baumannii has been detected in various food products, and the extent to which the food chain serves as a reservoir for this pathogen remains largely unclear. The current study aimed at investigating the prevalence of A. baumannii in dried spices, herbs, nuts and dried fruits. The ability of 20 recovered A. baumannii isolates to resist antibiotics, form biofilms and tolerate desiccation was tested. Additionally, multi-locus sequence typing (MLST) was used to genotype the isolates. The antibiotic susceptibility testing revealed that most of the isolates were susceptible, and displayed strong ability to form biofilms. MLST revealed 11 new sequence types (STs), while 9 isolates belonged to 7 known STs. Interestingly, 5 isolates (25%) were able to survive the desiccation conditions up to 56 days. This is the first study to demonstrate that spices and herbs are potential reservoirs for A. baumannii, which underlines the importance of continuous epidemiological surveillance in spices and dried herbs to reduce the risk of A. baumannii spread. Moreover, our findings highlights the need for quality control measures in the processing of dried spices and herbs.