Serotypes ofSalmonellaIsolated from Faeces of Patients with Acute Diarrhoea in Gwangju Area, Korea, During 2000-2009

Antimicrobial Resistance Profiles and Molecular Characteristics of Salmonella enterica Serovar Agona Isolated from Food-Producing Animals During 2010-2020 in South Korea

Multidrug-resistant (MDR) Salmonella enterica serovar Agona infections affect public health globally. This investigation aimed to ascertain the antimicrobial resistance profiles and molecular characteristics of Salmonella Agona isolates obtained from food-producing animals. A total of 209 Salmonella Agona isolates were recovered from mostly chickens (139 isolates), pigs (56 isolates), cattle (11 isolates), and ducks (3 isolates) between 2010 and 2020 in South Korea. In addition, these Salmonella Agona isolates were obtained from 25 slaughterhouses nationwide. Furthermore, this serotype suddenly increased in chickens in 2020. Salmonella Agona from chickens showed high resistance (69-83%) to ampicillin, streptomycin, tetracycline, trimethoprim/sulfamethoxazole, and chloramphenicol. Moreover, chicken/duck isolates (83.1%) showed significantly higher levels of MDR than cattle/pig isolates (1.5%). For molecular analysis by pulsed-field gel electrophoresis, infrared spectroscopy biotyping, and multilocus sequence typing in combination, a total of 23 types were observed. Especially two major types, P1-III-2-13 and P1-IV-2-13, comprised 59.3% of the total isolates spreading in most farms. Moreover, Salmonella Agona sequence type (ST)13 was predominant (96.7%) among three different STs (ST13, ST11, and ST292) widely detected in chickens (94.3%) in most farms located nationwide. Taken together, MDR Salmonella Agona in chickens might pose a potential risk to public health through direct contact or the food chain.

Prevalence of Multidrug Resistant Salmonellae with Increasing Frequency of Salmonella enterica Serovars Kentucky and Virchow among Hospitalized Diarrheal Cases in and around Delhi, India

Non-typhoidal salmonellae (NTS) are a major cause of acute diarrhea with characteristic multidrug resistance (MDR). In a hospital-based study, 81 NTS were isolated and tested for serotypes and antimicrobial resistance (AMR). Salmonella enterica isolates were classified into 7 different typable serovars, however, 19 (23%) isolates remained untypable. The most common serovars were S. Kentucky (48%), and S. Virchow (22%). Most of the NTS isolates displayed resistance to nalidixic acid (NA) (73%), ciprofloxacin (CIP) (48%), ampicillin (AM) and norfloxacin (NOR) (36% each), and gentamicin (CN) (31%). The AMR profiles for CN and NA; and AM, CIP, NA and NOR, were found to be high in S. Virchow (83%) and S. Kentucky (43%), respectively. Analysis of the pulsed-field gel electrophoresis patterns of S. Kentucky revealed 3 clusters. S. Kentucky has clones closely related to become prominent in recent years in Delhi. The AMR appears to be consistent with the change in MDR patterns during 2014-2017. The observed prevalence of S. Kentucky and S. Virchow in large numbers of diarrheal cases is novel. The NTS are mostly resistant to fluoroquinolones, which is the current drug of choice for treating diarrheal cases. MDR is very common among clonally related S. Kentucky.

Antibiotic Resistance Patterns and Serotypes of Salmonella spp. Isolated at Jeollanam-do in Korea

OBJECTIVES

Few long-term studies have been conducted on the serotype and antibiotic resistance patterns of Salmonella speices (spp.) The aim of this study was to determine the serotypes and antibiotic resistance patterns of Salmonella spp. isolated at Jeollanam-do in Korea from 2004 to 2014.

METHODS

A total of 276 Salmonella samples were evaluated. Serotyping was carried out according to the Kauffmann-White scheme. Antibiotic susceptibility was determined using the Vitek II system with an AST-N169 card.

RESULTS

A total of 22 different serotypes were identified, and the major serotypes were Salmonella Enteritidis (116 strains, 42.0%) and Salmonella Typhimurium (60 strains, 21.7%). The highest resistance was observed in response to nalidixic acid (43.4%), followed by ampicillin (40.5%) and tetracycline (31.6%). Resistance to nalidixic acid was detected in 81.0% of S. Enteritidis. Multidrug resistance was detected in 43.3% of Salmonella spp. S. Enteritidis and S. Typhimurium presented the highest resistance (98.3%) and multidrug resistance rate (73.3%), respectively. The most highly observed antibiotic resistance pattern among Salmonella spp. in this study was ampicillin-chloramphenicol (14 strains, 5.7%).

CONCLUSION

Overall, S. Enteritidis and S. Typhimurium showed higher antibiotic resistance than the other Salmonella serotypes tested in this study. Our study will provide useful information for investigating the sources of Salmonella infections, as well as selecting effective antibiotics for treatment.