Identification and Antimicrobial Susceptibility of Serovar Choleraesuis in a Salmonella Outbreak in Central-Western Albania

Abstract

Abstract Swine paratyphoid infection is caused by the swine-adapted Salmonella enterica serovar Choleraesuis. Infected individuals remain healthy carriers, and if the infection occurs at the end of the fattening period, it could pose a threat to human health. The present work aimed to assess antimicrobial susceptibility of S. enterica serovar Choleraesuis serotypes isolated from domestic pigs in central-western Albania, and to assess the presence and circulation of antibiotic-resistant paratyphoid Salmonella in Albania. Increasing mortality was reported in 6 farrow-to-finish pig farms located in the western and central parts of the country from December 2022 to April 2023. Post-mortem examination revealed macroscopic lesions in different organs indicating Salmonella infection. Four serovars Choleraesuis were isolated out of 24 different Salmonella spp. Multi-drug resistance (MDR), extensively drug-resistant (XDR), and Pan Drug Resistance (PDR) was calculated. Three out of four isolates showed MDR, and one out of four showed XDR. All S. enterica serovar Choleraesuis isolates showed resistance to at least two antimicrobials. Three isolates were observed to display MAR index values >0.2 indicating high-risk contaminated sources with frequent use of antibiotics. The predominant antimicrobial resistance was observed for amoxicillin, oxytetracycline, sulfamethoxazole, trimethoprim, spiramycin, colistin sulpha, and doxycycline. The findings emphasize the importance of strict biosecurity measures in affected pig farms, and prevention and control of S. enterica serovar Choleraesuis in the farm sanitary programs in Albania.