BACKGROUND: Salmonella, an important foodborne pathogen, was estimated to be responsible for 95.1 million cases and 50,771 deaths worldwide. Sixteen serovars were responsible for approximately 80% of Salmonella infections in humans in China, and infections caused by a few uncommon serovars have been reported in recent years, though not with S. Welikade. This study reports the first clinical case caused by S. Welikade in China and places Chinese S. Welikade isolates in the context of global isolates via genomic analysis. For comparison, S. Welikade isolates were also screened in the Chinese Local Surveillance System for Salmonella (CLSSS). The minimum inhibitory concentrations (MICs) of 28 antimicrobial agents were determined using the broth microdilution method. The isolates were sequenced on an Illumina platform to identify antimicrobial resistance genes, virulence genes, and phylogenetic relationships.
RESULTS: The S. Welikade isolate (Sal097) was isolated from a two-year-old boy with acute gastroenteritis in 2021. Along with the other two isolates found in CLSSS, the three Chinese isolates were susceptible to all the examined antimicrobial agents, and their sequence types (STs) were ST5123 (n = 2) and ST3774 (n = 1). Single nucleotide polymorphism (SNP)-based phylogenetic analysis revealed that global S. Welikade strains can be divided into four groups, and these three Chinese isolates were assigned to B (n = 2; Sal097 and XXB1016) and C (n = 1; XXB700). In Group B, the two Chinese ST5123 isolates were closely clustered with three UK ST5123 isolates. In Group C, the Chinese isolate was closely related to the other 12 ST3774 isolates. The number of virulence genes in the S. Welikade isolates ranged from 59 to 152. The galF gene was only present in Group A, the pipB2 gene was only absent from Group A, the avrA gene was only absent from Group B, and the allB, sseK1, sspH2, STM0287, and tlde1 were found only within Group C and D isolates. There were 15 loci unique to the Sal097 isolate.
CONCLUSIONS: This study is the first to characterize and investigate clinical S. Welikade isolates in China. Responsible for a pediatric case of gastroenteritis in 2021, the clinical isolate harbored no antimicrobial resistance and belonged to phylogenetic Group B of global S. Welikade genomes.

Minimum inhibitory concentrations (MIC) assays are often questioned for their representativeness. Especially when foodborne pathogens are tested, it is of crucial importance to also consider parameters of the human digestive system. Hence, the current study aimed to assess the inhibitory capacity of two antibiotics, ciprofloxacin and tetracycline, against Salmonella enterica and Listeria monocytogenes, under representative environmental conditions. More specifically, aspects of the harsh environment of the human gastrointestinal tract (GIT) were gradually added to the experimental conditions starting from simple aerobic lab conditions into an in vitro simulation of the GIT. In this way, the effects of parameters including the anoxic environment, physicochemical conditions of the GIT (low gastric pH, digestive enzymes, bile acids) and the gut microbiota were evaluated. The latter was simulated by including a representative consortium of selected gut bacteria species. In this study, the MIC of the two antibiotics against the relevant foodborne pathogens were established, under the previously mentioned environmental conditions. The results of S. enterica highlighted the importance of the anaerobic environment when conducting such studies, since the pathogen thrived under such conditions. Inclusion of physicochemical barriers led to exactly opposite results for S. enterica and L. monocytogenes since the former became more susceptible to ciprofloxacin while the latter showed lower susceptibility towards tetracycline. Finally, the inclusion of gut bacteria had a bactericidal effect against L. monocytogenes even in the absence of antibiotics, while gut bacteria protected S. enterica from the effect of ciprofloxacin.

BACKGROUND: Salmonellae are gram-negative, facultatively anaerobic Enterobacteri-aceae consisting of two species, Salmonella enterica and Salmonella bongori. Invasive diseases, such as meningitis, result in hospitalization, short and long-term complications, and high mortality rates.
METHODS: A 4-month-old baby girl was admitted to a district hospital because of diarrhea and fever. WBC count, urinalysis, urine cultures, and stool cultures were normal. She was treated with intravenous cefuroxime for 5 days. She was discharged on oral cefprozil for 5 days. After the end of therapy, she was admitted again to the same hospital with fever, diarrhea, vomits, and irri-tability. Cerebrospinal fluid examination revealed pleocytosis, while S. enterica was isolated. Em-pirical therapy with ceftriaxone, amikacin, and dexamethasone was started. Because of intracranial hypertension signs, she was transferred to the pediatric intensive care unit of our tertiary hospital. Therapy continued with intravenous ceftriaxone. Brain MRI revealed subarachnoid space dilata-tion. Increased head circumference and pulsating bregmatic fontanel led to a new cerebral MRI, in which ventricular dilatation and extraparenchymal subdural collection were noted. Ceftriaxone was changed to cefotaxime and ciprofloxacin was added. She remained clinically well; her brain MRI, a week later, showed marked improvement, and the course of intravenous antibiotics for 5 weeks was completed. Her baseline immunodeficiency screening tests were normal and repeat MRI two months post-treatment cessation did not reveal the previous abnormalities.
CONCLUSIONS: Invasive Salmonella diseases, such as meningitis, are very uncommon in industrial countries nowadays, and the optimal management is yet not well established. Late onset of com-plications from Salmonella meningitis warrants more thorough neurodevelopmental follow-ups.

Mycotic (infected) aortic aneurysm is a severe clinical condition with high morbidity and mortality. Salmonella spp. is a Gram-negative, rod-shaped bacteria that is typically limited to the gastrointestinal tract and resolves spontaneously but can progress to invasive infections such as bacteremia. Serious complications may arise, particularly in debilitated, elderly, and neonatal patients. We describe the case of a 74-year-old female with a history of diabetes and hypertension who presented with shortness of breath, fever, chills, abdominal pain, vomiting, and diarrhea. The patient\'s blood culture tested positive for Salmonella enterica, and she was given ceftriaxone based on the results, but he remained symptomatic. A computed tomography scan of the chest with contrast revealed a mycotic aneurysm of the thoracic aorta. The patient was urgently transferred to a higher level of care and underwent emergency thoracic endovascular aortic repair with stenting and intravenous antibiotics. The presence of an infected aneurysm and associated abscess formation in such high-risk patients makes the endovascular approach more suitable than other options such as open surgery, aneurysmal excision and ligation without arterial reconstruction, excision with immediate reconstruction, and excision with interval reconstruction.

Non-typhoidal Salmonella typically presents with gastroenteritis. However, an invasive Salmonella infection, which may be typically seen in immunocompromised patients, has a propensity for aortic involvement, especially in patients with risk factors for atherosclerosis. Here we present a 60-year-old female with multiple comorbid conditions and currently on immunosuppressants for rheumatoid arthritis, who presented with nausea, vomiting, and fever of three weeks duration and was found to have Salmonella bacteremia. Blood cultures were positive for Salmonella enterica. Computed tomography (CT) abdomen with contrast was concerning for mycotic aortitis. The patient underwent endovascular repair of an aortic ulcer and was treated with a six-week course of ceftriaxone. Mycotic aneurysm is a rare but potentially fatal complication of invasive Salmonella infection. It occurs typically in older men with atherosclerotic risk factors. It mostly presents as fever, back pain, and/or abdominal pain. Our patient was a middle-aged female who presented with non-specific symptoms. CT angiogram is the diagnostic modality of choice and treatment may require surgical vascular repair and long-term antibiotics. A high level of suspicion is needed to diagnose Salmonella-related mycotic aneurysm/aortitis. Early diagnosis and treatment may improve the mortality.

Non-typhoidal Salmonellosis are an important cause of gastroenteritis and invasive disease in developing countries, with increase resistance and mortality in paediatric age group. We report here, a rare case of bacteremia and brain abscess in a 3year old female child with Salmonella enterica serovar Give as a causative organism.

Reptiles, including snakes, can be asymptomatically infected with multiple pathogen microorganisms, including Salmonella spp., which is considered an important concern for public and animal health. Small and uninhabited isles are quite ecologically different from mainland and represent interesting fields of study, to discover unexpected biological and microbiological aspects of their wild inhabitants. This work reports the presence of the very rare Salmonella enterica serovar Yopougon, isolated in a carcass of a native wild snake (Hierophis viridiflavus) from an Italian uninhabited island of Mediterranean Sea, Montecristo. To our knowledge, S. enterica serovar Yopougon was previously isolated only once 34 years earlier in Ivory Coast, from a human fecal sample. In the present study, we present the genomic characterization of the new isolate, the phylogenetic comparison with the previously isolated S. enterica serovar Yopougon strain of human origin and with other sequences available in public databases. In addition, an extensive review of available data in the literature and from our case history is provided. Our finding represents an example of the ability of some pathogens to travel for very long distances within their hosts and then to infect others, even from different taxa.

Non-typhoidal Salmonella infections (NTSI) can cause bacterial diarrhea, mostly leading to self-limiting gastroenteritis. However, in at-risk populations, NTSI can have severe complications. As transmission is most commonly foodborne, infection is rare in the breast- or bottle-fed very young. Another route is increasingly implicated, however, in newborns and infants especially: Contact with reptiles and amphibians. We describe infection with Salmonella enterica subsp. enterica ser. Monschaui (S. Monschaui), transmitted from bearded dragons, in a three-week-old boy. The boy initially appeared well, on the next morning deterioration was dramatic, with tachypnea, tachycardia, and mottled skin. Gram-negative sepsis was documented on day 2. His case prompted a review of published instances of reptile- and amphibian-associated salmonellosis (RAAS), summarized here. Association of S. Monschaui infection with exposure to reptiles and amphibians prompted inquiry into household pets. The parents had kept bearded dragons (Pogona sp.), the last of which died two weeks before the patient was born; confirmation of colonization with S. Monschaui was thus precluded. Among 63 reports (-5,000 cases) of RAAS or S. Monschaui, 62 appeared between 1995 and 2022, 10 were single case reports, and 53 were original articles with -5,000 cases; vectors included turtles, frogs, lizards, and snakes. RAAS is not a new phenomenon, but its incidence recently has risen due to the increased popularity of reptiles and amphibians as non-traditional pets. These animals can carry Salmonella sp. and transmit it to humans, posing a risk particularly to infants and other vulnerable persons. Risk mitigation requires that those bringing such pets into the home be informed of dangers associated with reptile and amphibian contact; that those selling reptiles and amphibians be mandated to inform customers comprehensively may be in order.

BACKGROUND: Salmonella enterica serotype Choleraesuis infections usually cause self-limited gastrointestinal diseases. Extra-abdominal infections are often secondary to bacteremia in immunocompromised individuals and are relatively rare in immunocompetent hosts.
METHODS: A 65-year-old Caucasian female initially presented to the thoracic surgery clinic due to a poorly healing wound on her chest. Her condition started after a mechanical fall hitting her chest with interval development of a tender lump that later spontaneously drained. A chest computed tomography scan with intravenous contrast demonstrated an abnormal infiltration with small foci of fluid and air consistent with a small abscess anterior to the left seventh costal cartilage. Aspirate culture of the abscess grew S. enterica serotype Choleraesuis susceptible to ampicillin and trimethoprim/sulfamethoxazole. The patient had no prior history of signs or symptoms of gastrointestinal infection. Blood cultures were negative. With a background of penicillin allergy, she was treated with trimethoprim/sulfamethoxazole, and later with ceftriaxone due to persistent drainage of the wound. Follow-up chest computed tomography scan with intravenous (IV) contrast showed continued abnormal findings previously seen in the computed tomography scan with the appearance of a sinus tract. The patient subsequently underwent surgical debridement and partial resection of the left seventh costochondral cartilage and excision of the fistula. She had an uneventful recovery and complete resolution of her condition.
CONCLUSIONS: We report a rare case of chest wall abscess with associated costochondritis due to S. enterica serotype Choleraesuis in a patient with no evidence of immunodeficiency nor history of bacteremia. Extraintestinal infections due to Salmonella without documented bacteremia have been previously reported in the literature. History of local trauma to the affected area might contribute to the seeding of infection. Diagnosis is often accomplished by clinical evaluation and culture of the affected area. Treatment often involves targeted antibiotic therapy but may require surgical intervention to achieve source control and cure.

Salmonella Reading is a rare serotype of Salmonella enterica and is associated with sporadic cases and rare outbreaks worldwide. This article describes a rare case of generalized S. Reading infection imported from Indonesia to Moscow, Russia. A 37-year-old man was admitted to the hospital with fever, weakness, and headache after returning from Indonesia. During his stay in Indonesia, he developed symptoms of a gastrointestinal infection, which resolved there. However, upon return to Moscow, his condition worsened due to high fever, and he was diagnosed with a generalized salmonellosis caused by S. Reading (positive blood and stool culture). This case highlights the importance of differential diagnosis in patients with fever. The health risks associated with traveling to exotic countries and the importance of preventive measures are emphasized. This is the first published case of S. Reading in Eastern Europe.