Microbial risks of raw camel milk: Salmonella identification and antimicrobial susceptibility profiling in the pastoral settings of Somali region, Ethiopia

Abstract

Abstract Background Camel milk is the primary means of ensuring food security in pastoral settings of the Somali Region, where usually consumed raw. This untreated camel milk is believed to be a major source of foodborne illnesses; yet, the microbial risks—especially Salmonella contamination of raw camel milk and its antibiograms—are poorly understood in the area. Thus, the study was conducted to identify Salmonella contamination in raw camel milk, determine its antibiograms, and assess community perceptions and public health risks of raw camel milk consumption in the study area. Methods A cross-sectional study was conducted to assess community awareness in public health risks of raw camel milk and identify Salmonella contamination in the production chains: udders, buckets, and bulk milk of raw camel milk, and determine its antibiogram. A total of 384 raw camel milk samples were collected from buckets ( n = 225), bulk milk ( n = 49), and udders ( n = 110) and bacteriologically analyzed by isolation and antimicrobial susceptibility testing. Chi-square, Phi, and Cramer’s V-value were employed to assess the factors and the strength of associations with Salmonella recovery rates, respectively. Result Out of 384 total samples analyzed, 165 Salmonella isolates were recovered, representing an overall recovery rate of 43.0%. These isolates comprised 56 typhoidal Salmonella species (representing 14.6% of total samples) and 109 non-typhoidal Salmonella species (representing 28.4% of total samples). A high recovery rate of Salmonella was observed in bucket milk (109; 48.4%), and bulk milk (20; 40.8%), and bacterial isolation rate were strongly associated (all, p < 0.05; Phi = 0.599 to 0.491) with poor milkers’ hand hygiene (122; 84.1%), buckets and bulk milk not cleaned regularly (84; 76.4%, and 17; 70.8%) respectively, and unsmoked buckets (92; 68.7%). The invitro antibiogram confirmed that isolates were resistant to Erythromycin (100%), Ampicillin (87.5%), and Trimethoprim-sulfamethoxazole (62.5%), while showing high susceptibility to Streptomycin and Amikacin (100%) and Ceftriaxone (66.7%). Nine (75%) isolates of non-typhoidal Salmonella species developed multidrug resistance (MDR), resistant to Trimethoprim-sulfamethoxazole, Ampicillin, and Chloramphenicol. Notably, only the non-typhoidal Salmonella were resistant to Ceftriaxone (41.7%); conversely, the typhoidal Salmonella were highly susceptible (83.3%). Also, all typhoidal Salmonella isolates (100%) were completely resistant to Ampicillin. Conclusion A high prevalence of both typhoidal and non-typhoidal Salmonella species is identified in raw camel milk under poor hygienic practices of milking and public health awareness. The presence of multidrug-resistant Salmonella isolates may have a public health concern in causing food-borne illness and posing a drug resistance threat.