Early-onset Streptococcus pneumoniae Neonatal Sepsis and Meningitis in the 13-valent Vaccine Era

Abstract

To the Editors: Streptococcus pneumoniae is a rare cause of invasive infections in neonates, and in the United States and Europe accounts for 1% to 5.5% of neonatal sepsis cases, being more prevalent in developing countries (11.5%).1,2 Most infections occur during the second or third week of life, with a high case fatality rate (50%).1 To know the serotypes involved in neonatal infections in the era of pneumococcal conjugate 13-valent vaccine (PCV13) would be of interest. We report a case of early-onset pneumococcal sepsis and meningitis by serotype 7F, a serotype included in PCV13. CASE REPORT A 1-day-old male neonate presented with fever, grunting, tachypnea and septic appearance. He was vaginally born at term, weighed 2635 g and the Apgar score was 8/9. There was no history of maternal fever, chorioamnionitis and prolonged rupture of membranes or colonization with Streptococcus agalactiae. The chest radiograph was normal. Laboratory investigation revealed pancytopenia, coagulopathy and increased C-reactive protein. Cerebrospinal fluid analysis showed 160 leukocytes (85% polymorphonuclear cells), protein 5.6 g/L and glucose 5 mg/dL; Gram-positive cocci were observed on the Gram-stained smear. Cultures of blood and cerebrospinal fluid were positive for S. pneumoniae. The mother was asymptomatic, but a vaginal culture showed a pure growth of S. pneumoniae. All isolates belonged to serotype 7F and shared identical pattern of pulse field gel electrophoresis, being susceptible to ampicillin and cefotaxime. Treatment with ampicillin plus cefotaxime was administered, but the patient developed septic shock and massive brain hemorrhage that caused his death. COMMENT Early-onset invasive disease caused by S. pneumoniae occurs during the first 72 hours of life and causes sepsis, meningitis and pneumonia. It is less frequent than late onset infections and has a worse prognosis, especially when it starts before 48 hours of life or is secondary to an invasive maternal infection.3 In early-onset disease, pneumococci may reach the fetus via the transplacental route, secondary to maternal bacteremia, ascending from the maternal genital tract or passage through the birth canal. Pneumococcus is not present in the normal vaginal flora, and several studies have demonstrated that genital colonization by this microorganism is uncommon (<0.03%).2,4 Our patient’s mother was asymptomatic, but her vagina was heavily colonized by pneumococci. In this case, the newborn most likely acquired the infection vertically while passing through the colonized birth canal and showed clinical features similar to those of S. agalactiae early-onset infections. The serotype of the isolates, maternal and newborn, was 7F, one of the new serotypes included in PCV13. In Spain, serotype 7F along with 1 and 19A were the most prevalent in invasive infections in 2010, when PCV13 was released.5 However, PCV13 coverage in our children is only 56% because it is not included in the national immunization program, and consequently there is no herd immunity. Although vaccination of childbearing age women with PCV13 would not be cost effective, it could be useful until PCV13 achieves greater coverage in our population.6 Julio F. Fothy, MD Susanne Vetter, MD Antonio Iñigo, MD José Gil, MD José L.Pérez, PhD Juan A. Hervás, MD, PhD Departments of Microbiology and Pediatrics Son Espases University Hospital University Institute of Health Sciences-IUNICS University of The Balearic Islands Palma de Mallorca, Spain