Late-onset Neonatal Infections 1997 to 2017 Within a Cohort in Western Sweden—The Last 21 Years of a 43-Year Surveillance

Abstract

Invasive infections affect neonates with the risk of severe morbidity and death, and Streptococcus agalactiae (Group B streptococcus, GBS) remains one of the most common pathogens. The aim of this thesis was to assess infections among neonates and infants, focusing on GBS to better understand prevention and treatment. Clinical data and outcomes were collected from patients' medical records.Paper I was a prospective cohort study of GBS isolates obtained from adults and children with an invasive GBS infection in the years between 2004 and 2009. The study showed that among infants, serotype III was the most prevalent (48%), but serotype V (39%) was most common among adults. Paper II and III were observational, retrospective studies on early-onset (EO) and late-onset (LO) invasive infections among infants living within Gothenburg or five surrounding municipalities, from whom a pathogenic organism was isolated from blood or cerebrospinal fluid during the years 1997-2017. The studies showed that EO infections decreased from 1.4 to 0.9 per 1000 live births from 1997-2007 to 2008-2017. During the same period, the incidence of LO infections increased from 2.0 to 3.1 per 1000 live births. The case fatality rate remained unchanged for both studies. Paper IV was a cohort study of GBS isolates obtained from pregnant or postpartum women and infants with an invasive GBS infection in Western Sweden during 1988-2001 and 2004-2009. The study showed that invasive isolates exhibited more pigmentation compared to commensal isolates.Conclusions: These studies have shown that the incidence of EO infections has declined, but for LO infections, it has increased. The serotype distribution of invasive GBS strains has remained the same. The invasive strains exhibit more pigmentation, which provides the basis for additional studies to determine if routine laboratory testing can be safely used to identify the GBS strains that put the unborn child at risk.

Invasive Group B Streptococcal Disease in Neonates and Infants, Italy, Years 2015–2019

“…A very comprehensive Swedish retrospective study that encompassed forty-three years of surveillance on LOD (using the case definition of symptoms from 72 h of life onward) demonstrated that GBS-LOD incidence significantly doubled in the last 20 years (from 0.16 to 0.33/1000 livebirths). The increase of infection mostly regarded infants born extremely preterm and it represented the first cause of meningitis [45].…”

A decade of neonatal sepsis in Stockholm, Sweden: Gram-positive pathogens were four times as common as Gram-negatives

“…The risk of EOS increases with the occurrence of chorioamnionitis, prolonged rupture of membranes (i.e., > 18 h before birth) and maternal GBS colonization [ 9 ]. In late-onset sepsis (LOS), symptoms occur at > 72 h of age, the infection is usually hospital-acquired and caused by Gram-positive bacteria (GPB), such as CoNS and Staphylococcus aureus [ 10 – 12 ]. Low birth weight and gestational age increase the risk of LOS [ 10 , 12 ].…”

“…In late-onset sepsis (LOS), symptoms occur at > 72 h of age, the infection is usually hospital-acquired and caused by Gram-positive bacteria (GPB), such as CoNS and Staphylococcus aureus [ 10 – 12 ]. Low birth weight and gestational age increase the risk of LOS [ 10 , 12 ].…”