Neonatal Salmonella Paratyphi B Sepsis: A Case Report

Introduction

Enteric fever is uncommon in children <2 y of age and rare in neonates. In a recent large study on neonatal sepsis that included 840 culture positive neonates, Salmonella was not isolated in any of the samples. ¹ We report the case of a 26 d old baby who had Salmonella Paratyphi B septicemia.

Case Report

A 26 d old male baby was admitted to the Neonatal Intensive Care Unit (NICU) with the complaints of fever and decreased feeding for 2 d. There was no history of dullness or lethargy and the baby was passing urine and stools. The baby was a single, term baby with a birth weight of 1900 g. The baby was on breast feeds and inappropriately constituted formula milk by bottle. The baby weighed 1882 g at admission and was febrile (temperature 38.5°C), the respiratory rate was 76/min and the Downes score was 4/10. The heart rate was 170/min, pulses were well palpable, and the capillary refill time was <3 s. The baby was lethargic, sick looking, and the systemic examination was unremarkable. The blood sugar at admission was 78 mg/dL. The baby was given supportive care and oxygen by nasal prongs. Injection ampicillin and gentamicin were started by intravenous route after withdrawing a sample for automated blood culture and sensitivity and the baby was started on expressed breast milk by orogastric tube. The baby had a seizure on the day of admission, which was managed as per protocol. The complete blood count was within normal limits, C reactive protein was 29 mg/L, electrolytes were within normal limits, and meningitis was ruled out. The baby improved on day 2 of admission but continued to need oxygen by prongs. Blood culture revealed Salmonella Paratyphi B sensitive to ampicillin and cefotaxime. Cefotaxime was started and gentamicin was stopped on day 3 of admission. The baby gradually improved, became afebrile on day 4 of admission, was maintaining SpO in room air by day 5, and started accepting breast feeds. The urine culture of the baby also did not grow any organism. A stool sample of the mother was sent for culture, which did not isolate any pathogenic organisms. The baby was discharged after completion of 14 d of intravenous antibiotics.

Discussion

There have been sporadic case reports of Salmonella Typhi and Paratyphi A sepsis in neonates, mainly from India and other developing and under developed countries, but Paratyphi B being very uncommon.^{2, 3} Neonatal Salmonella meningitis and brain abscess cases have also been reported, but they are mainly caused by nontyphoidal strains. ⁴ Salmonella species may cause early onset as well as late onset sepsis. Vertical transmission is most likely in early onset sepsis, which could be by transplacental route or from the birth canal during vaginal delivery. The mother may be asymptomatic or symptomatic with fever as the chief complaint just before delivery. Blood culture of the mother should be done if she is symptomatic, urine and stool samples should be also sent if the mother is asymptomatic. In our case the mother was asymptomatic, and her stool culture did not isolate any pathogenic organisms. Mohanty et al presented a case series of 5 newborns with Salmonella Typhi and Paratyphi A septicemia. All babies had early onset sepsis but none of the mothers’ sample was positive for Salmonella. ⁵ They also reviewed other cases of neonatal typhoid and paratyphoid cases (all cases were Paratyphi A) reported in the past and found that the mothers’ culture was positive in <10% cases. Babies presenting with late onset septicemia may acquire the infection due to contaminated feeds. The source of infection may be the mother who is a carrier. In our case, the baby was on bottle feeds so most likely route of infection was feco-oral. The infection could have come through contaminated water used for reconstituting formula feeds. Nontyphoidal Salmonella species have been reported to cause outbreaks in nurseries. The source of infection in such outbreaks can be through suction devices, resuscitation equipment, thermometers, etc. ⁶ There has been a report of Salmonella typhimurium outbreak that was linked to feeding the neonates with pooled expressed breast milk, one of the mothers’ breastmilk was positive for Salmonella typhimurium.^{7, 8} There have been individual case reports of neonatal salmonella, the route of spread being breast milk and the babies were exclusively breastfed. ⁹

Salmonella sepsis presents with nonspecific signs and symptoms, seen in septicemia due to any other organism. Features typical of typhoid fever seen in older population are missing. The baby may have jaundice, fever, respiratory distress, diarrhea, seizures, and cough. Asymptomatic infection or fecal carriers have also been reported in neonates. Asymptomatic infection may be explained by transient bacteremia in cases where there is vertical transmission. Salmonella also causes suppurative arthritis and osteomyelitis in neonates. Mortality reported is high (30%) in cases of neonatal salmonella infection.

Conclusion

It is difficult to suspect Salmonella Paratyphi B infection in neonates as there are no specific clinical or laboratory markers for it. Early recognition of Salmonella sepsis is important as blood isolates of Salmonella are intrinsically resistant to aminoglycosides. The key to diagnosis is sending a blood culture sample in all symptomatic newborns before starting antibiotics. Exclusive breastfeeding will protect the baby from acquiring infection from feco-oral route.