Purpose: The objectives of this study were to determine if the imported spices from India could serve as a vector for the spread of NDM-1-positive Enterobacteriaceae.
Methods: Samples (n=28) of the imported dried spices produced in India were collected from an international market located in Atlanta, GA. Each spice sample was weighed and analyzed microbiologically. Serial dilutions of each spice were then plated on TSA, ESBL, KPC, and coliform petrifilm plates. Both ESBL and KPC plates detected the presence of the NDM-1-producing bacteria. The selected NDM-1-producing colonies were picked, purified, tested for susceptibility to 15 antibiotics by determining minimum inhibition concentration (MIC), and further tested for species level and the gene encoding NDM-1.
Results: Total bacterial counts on TSA ranged from <100 to 7.3 x 106 CFU/g with the highest count in the black pepper sample. Ten samples were positive for coliforms ranging from <5 to 2.5 x 104 CFU/g, with the highest count in the ground turmeric. Seven samples (Garam Masala, turmeric powder, mustard seed, fennel seed, white chili powder, ground turmeric seed, and ground coriander) were positive for NDM-1 positive bacteria with counts ranging from 750 to 1.4 x 104 CFU/g and 75 to 1.1 x 104 CFU/g on ESBL and KPC, respectively. The Garam Masala sample contained the highest count on both ESBL and KPC. Among five NDM-1 positive isolates, 2 isolates were resistant to two antibiotics, whereas each of the 3 other isolates was resistant to 4, 5, and 7 antibiotics, respectively. The prevalence of antibiotic resistance was in the following order: cefoxitin, nalidixic acid, ampicillin, and ceftiofur.
Significance: Our results demonstrate that NDM-1-positive bacteria are present in imported dried spices from India, and these products could serve as a vector for the spread of the NDM-1-producing Enterobacteriaceae.