Identifying a list of Salmonella serotypes of concern to target for reducing risk of salmonellosis.

There is an increasing awareness in the field of Salmonella epidemiology that focusing control efforts on those serotypes which cause severe human health outcomes, as opposed to broadly targeting all Salmonella, will likely lead to the greatest advances in decreasing the incidence of salmonellosis. Yet, little guidance exists to support validated, scientific selection of target serotypes. The goal of this perspective is to develop an approach to identifying serotypes of greater concern and present a case study using meat- and poultry-attributed outbreaks to examine challenges in developing a standardized framework for defining target serotypes.

Clinical Characteristics, Antimicrobial Resistance, Virulence Genes and Multi-Locus Sequence Typing of Non-Typhoidal Salmonella Serovar Typhimurium and Enteritidis Strains Isolated from Patients in Chiang Mai, Thailand.

Non-typhoidal salmonellosis (NTS) caused by ingesting Salmonella enterica contaminated food or drink remains a major bacterial foodborne disease. Clinical outcomes of NTS range from self-limited gastroenteritis to life-threatening invasive NTS (iNTS). In this study, we isolated Salmonella spp. from the stool and blood of patients hospitalized at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, between 2016-2021 (a total of 395 cases). Then, serovar Typhimurium and Enteritidis were identified and further characterized by multiplex PCR, and multi-locus sequence typing. Our data show that multidrug resistance (MDR) sequence type 34 (ST34) and ST11 are the predominant sequence types for serovars Typhimurium and Enteritidis, respectively. Most S. Typhimurium ST34 lacks spvB, and most S. Enteritidis ST11 harbor sseI, sodCI, rpoS and spvB genes. NTS can be found in a wide range of ages, and anemia could be a significant factor for S. Typhimurium infection (86.3%). Both S. Typhimurium (6.7%) and S. Enteritidis (25.0%) can cause iNTS in immunocompromised patients. S. Typhimurium conferred MDR phenotype higher than S. Enteritidis with multiple antibiotic resistance indexes of 0.22 and 0.04, respectively. Here, we characterized the important S. Typhimurium, S. Enteritidis, and human clinical factors of NTS within the region.

Therapeutic effects of oral administration of lytic Salmonella phages in a mouse model of non-typhoidal salmonellosis.

Acute non-typhoidal salmonellosis (NTS) caused by a Gram-negative bacterium Salmonella enterica serovar Typhimurium (S. Tm) is one of the most common bacterial foodborne diseases worldwide. Bacteriophages (phages) can specifically target and lyse their host bacteria, including the multidrug-resistant strains, without collateral damage to other bacteria in the community. However, the therapeutic use of Salmonella phages in vivo is still poorly investigated. Salmonella phages ST-W77 and SE-W109 have previously been shown by our group to be useful for biocontrol properties. Here, we tested whether phages ST-W77 and SE-W109 can reduce Salmonella invasion into cultured human cells and confer a therapeutic benefit for acute NTS in a mammalian host. Human colonocytes, T84 cells, were treated with phages ST-W77, SE-W109, and its combination for 5 min before S. Tm infection. Gentamicin protection assays demonstrated that ST-W77 and SE-W109 significantly reduced S. Tm invasion and inflammatory response in human colonocytes. Next, streptomycin-pretreated mice were orally infected with S. Tm (108 CFU/mouse) and treated with a single or a combination of ST-W77 and SE-W109 (1010 PFU/mouse for 4 days) by oral feeding. Our data showed that phage-treated mice had lower S. Tm numbers and tissue inflammation compared to the untreated mice. Our study also revealed that ST-W77 and SE-W109 persist in the mouse gut lumen, but not in systemic sites. Together, these data suggested that Salmonella phages ST-W77 and SE-W109 could be further developed as an alternative approach for treating an acute NTS in mammalian hosts.

Anti-inflammatory Effect of Probiotic Limosilactobacillus reuteri KUB-AC5 Against Salmonella Infection in a Mouse Colitis Model.

Acute non-typhoidal salmonellosis (NTS) caused by Salmonella enterica Typhimurium (STM) is among the most prevalent of foodborne diseases. A global rising of antibiotic resistance strains of STM raises an urgent need for alternative methods to control this important pathogen. Major human food animals which harbor STM in their gut are cattle, swine, and poultry. Previous studies showed that the probiotic Limosilactobacillus (Lactobacillus) reuteri KUB-AC5 (AC5) exhibited anti-Salmonella activities in chicken by modulating gut microbiota and the immune response. However, the immunobiotic effect of AC5 in a mammalian host is still not known. Here, we investigated the anti-Salmonella and anti-inflammatory effects of AC5 on STM infection using a mouse colitis model. Three groups of C57BL/6 mice (prophylactic, therapeutic, and combined) were fed with 109 colony-forming units (cfu) AC5 daily for 7, 4, and 11 days, respectively. Then, the mice were challenged with STM compared to the untreated group. By using a specific primer pair, we found that AC5 can transiently colonize mouse gut (colon, cecum, and ileum). Interestingly, AC5 reduced STM gut proliferation and invasion together with attenuated gut inflammation and systemic dissemination in mice. The decreased STM numbers in mouse gut lumen, gut tissues, and spleen possibly came from longer AC5 feeding duration and/or the combinatorial (direct and indirect inhibitory) effect of AC5 on STM. However, AC5 attenuated inflammation (both in the gut and in the spleen) with no difference between these three approaches. This study demonstrated that AC5 confers both direct and indirect inhibitory effects on STM in the inflamed gut.

Non-typhoidal Salmonella bacteraemia in paediatric leukaemia patients.

Non-typhoidal Salmonella (NTS) is an important pathogen that causes gastroenteritis, bacteraemia, and focal infections. Herein, we present our experience with bloodstream infections caused by Salmonella in paediatric leukaemia patients, which has been reported for the first time in both Europe and the US. According to our research, NTS might be a cause of serious infections in paediatric haematology-oncology patients. Following a low bacterial diet and increasing the hygiene of both the children and their surroundings would be beneficial in preventing these infections.

A Case of Gallbladder Perforation Complicated by Acalculous Cholecystitis due to Non-Typhoidal Salmonella / 대한내과학회지

Salmonella infections can cause a variety of diseases, but acute acalculous cholecystitis complicated by gallbladder perforation occurs very rarely in adults. Here, we report a case of acute acalculous cholecystitis with gallbladder perforation after non-typhoidal group D Salmonella infection. A 71-year-old man was admitted with fever, chills, and watery diarrhea. Blood cultures taken on admission were positive for non-typhoidal group D Salmonella. The patient subsequently developed acute acalculous cholecystitis, and abdominal ultrasound and computed tomography revealed gallbladder perforation. Because of other medical problems, cholecystectomy could not be performed. The patient's symptoms and signs were not resolved, even after parenteral antibiotic injection and percutaneous cholecystostomy. Despite meticulous supportive care, the patient died after progression to multiple organ dysfunction.

The Serogroup and Antimicrobial Resistance of Salmonella spp. Isolated from the Clinical Specimens During 6 years in a Tertiary University Hospital / 대한임상미생물학회지

BACKGROUND: Recently, non-typhoidal salmonellosis is increasing and it constituted over 90% of total salmonellosis in 1990s. The antimicrobial resistance of non-typhoidal Salmonella gets higher. So we described the change of serogroup and antimicrobial resistance of Salmonella isolated from clinical specimens in Ewha Womans University Mokdong Hospital during 6 years. METHODS: Clinical specimens were submitted from 1997 to 2002. Stool cultures were inoculated onto MacConkey (MAC) agar and Salmonella-Shigella (SS) agar and into Selenite F (SF) enrichment broth. Identification of Salmonella were performed by Vitek GNI card (BioMerieux, Marcy-I'Eltoile, France) and serotyping were done. Antimicrobial resistance test were performed by Vitek GNS card (BioMerieux, Marcy-I'Eltoile, France). RESULTS: From 1997 to 2002, 594 strains of Salmonella were isolated. Non-typhoidal Salmonella and Salmonella typhi constituted 94.4% and 5.6%. Non-typhoidal Salmonella were mainly composed of group B (21.5%) and group D (48.0%), but in 2002, group C (12.4%) and group E (27.9%) were increased in number. The antimicrobial resistance rate of non-typhpoidal Salmonella were 28% to ampicillin, 4.1% to SXT, 0.2% to ciprofloxacin and 0.7% to ceftriaxone. The animicrobial resistance rate of group B and D Salmonella showed 37.5% and 32.6% to ampicillin, 7.8% and 4.2% to SXT, respectively. CONCLUSIONS: Serogroup B and D Salmonella were most frequently isolated, but group C and E Salmonella have been increased in 2002. Antimicrobial resistance of group B and D Salmonella were higher than other serogroups and have been increased year by year.