Abstract
Introduction: Salmonella infection is one of the most common causes of gastroenteritis worldwide. It is associated with high morbidity and mortality if not treated properly. It has developed resistance to multiple antibiotics. These developments are concerning. This study sought to observe common patterns of invasive Salmonella infections, such as the common serotypes involved, presentation, sensitive investigations, and effective treatment. This study also aimed to examine the risk factors that can worsen the infection and increase morbidity and mortality.
Methodology: This retrospective analysis included all patients who were diagnosed with invasive Salmonella infection at King Khalid University Hospital from May 2017 to December 2018. Most patients in this report were immunocompromised; however, a few previously healthy patients. Different types of specimens were collected. Twenty-two patients with invasive Salmonella were included in this study.
Results: Sixteen of them had underlying conditions. The most common presenting symptoms of illness were fever (n = 13), vomiting (n = 6), and diarrhea (n = 4). Most blood samples (94%) were positive for Salmonella. All patients were discharged except three who died; these were all older patients with comorbidities. Although four different antimicrobial resistance patterns were noticed in this study, ciprofloxacin
was the highest significant percentage (62.5%). Of five patients initially treated with ciprofloxacin, three of them expressed resistance to this antibiotic.
Conclusion: The findings of this study support that immunocompromised patients and people with extreme ages are more likely to have serious medical illnesses and at higher risk of infection with Salmonella spp. Therefore, this study emphasises the importance of antimicrobial judicious utilisation. Tackling the escalating antibiotic resistance could be approached by implementing advanced public education levels to maintain high standards of food and water safety. Moreover, the urge to investigating newer drugs against Salmonella with an acceptable safety profile is a cornerstone to attenuate the rapidly acquired bacterial resistance precisely for those who are immunocompromised. Furthermore, predicting the mortality, morbidity and the clinical response is feasible according to the patient parameters and comorbidities.

Key words: Immunocompromised; invasive; ciprofloxacin resistance; Salmonella; Saudi Arabia.