2534 Clinical Pearls in Current Diagnosis and Management of Salmonella paratyphi Infection

Abstract

INTRODUCTION: Typhoid and paratyphoid infections are rarely encountered in the United States, though are a major contributor to disease in developing countries. Growing virulence of organisms and lack of effective paratyphoid vaccination yield major public health concerns. We present two related individuals with typical symptoms of infection at varied presentation intervals. CASE DESCRIPTION/METHODS: A 31-year-old previously healthy female presented with four days of weakness, fevers, nausea, vomiting, and non-bloody diarrhea. She traveled to Pakistan two weeks prior. Admission examination was significant for fever of 100.5°F, hypotension, dry mucous membranes, ill appearance, and diffuse abdominal pain. Laboratory tests revealed white blood cell count 6.5 K/uL, hypoalbuminemia of 3.3 g/dL, alkaline phosphatase 178 U/L, AST 151 U/L, alanine aminotransferase ALT 130 U/L. Abdominal CT demonstrated terminal ileitis with right lower quadrant mesenteric lymphadenopathy up to 1.3 cm (Figure 1). Admission blood cultures grew SalmonellaParatyphi in both aerobic and anaerobic bottles, yet stool cultures remained negative on a second repeated sample. The laboratory reported sensitivity to ampicillin, ceftriaxone, ciprofloxacin and trimethoprim/sulfamethoxazole. However, additional requested sensitivity testing found nalidixic acid resistance, and minimum inhibitory concentration (MIC) of 1 to ciprofloxacin. The husband of the patient above, a 27-year-old male, presented two weeks after the discharge of his wife. He reported fever and chills for five days, with later abdominal cramping and diarrhea. On admission, white blood cell count was 4.9 K/uL with 19% bands, and liver function tests mildly elevated (AST 68 U/L, ALT 72 U/L). One of four blood culture bottles grew Salmonella Paratyphi with equivalent sensitivities. Two stool sample cultures were negative for Salmonella or enteric pathogen. Both patients completed two weeks of oral antibiotics with trimethoprim-sulfamethoxazole and did well subsequently. DISCUSSION: Our cases highlight diagnostic pearls of this condition including relative bradycardia after restoring hydration, leukopenia, transaminitis and ileitis. We demonstrate the utility of blood cultures, and how negative stool cultures may lead to false reassurance. Antibiotic resistance with Salmonella is challenging, particularly if providers are unaware of minimum inhibitory concentration cut-offs before selecting conventional fluoroquinolone therapy.