Changes in the incidence and epidemiology of neonatal group B Streptococcal disease over the last two decades in Crete, Greece

Abstract

Group B streptococcus (GBS) remains a leading cause of neonatal disease. However, GBS rates and prevention strategies vary considerably worldwide. Herein, we investigated the burden and epidemiological trends of neonatal GBS infections in our area (Greece) over the last two decades. We conducted a multicenter retrospective study that includes all cases of culture-proven GBS disease in infants <90 days old in the last 22 years. Neonatal GBS incidence was 0.17/1000 live births (95%CI: 0.11-0.21). A significant increase was noted during the second decade (0.23 vs 0.10/1000, P<0.05). Late onset disease (LOD) significantly increased during the second decade (0.08 vs 0.02, P<0.05). Infants in the LOD group had a higher risk of meningitis (RR 1.8, 95%CI: 1.23-2.71). Long-term neurological sequelae were reported in 42.8% of meningitis cases. The mortality rate was 8%. The incidence of neonatal GBS disease in our area is among the lowest reported, but an increase was noted the last decade mainly due a rise in the LOD. The burden of LOD, the mortality and long-term disability are still substantial, thus effective prevention strategies - including maternal vaccination for neonatal GBS - are needed.

Keywords: Group B streptococcus; early onset; incidence; intrapartum prophylaxis; late onset; neonatal infections.

Figure 1.

Annual incidence of Group B Streptococcus (GBS) infections in infants less than 90 days of age in Crete, Greece. The rate of all cases of GBS are depicted (circles, black line) as well as the incidence of early onset GBS disease (EOD, white bars) and late onset GBS disease (LOD, gray bars) per each year.

Figure 2.

Group B Streptococcus (GBS) rates of early onset disease (EOD), late onset disease (LOD) and total rates of GBS invasive disease in infants less than 90 years old between the decades 1995-2005 and 2006-2016 in Crete, Greece. Boxes show 5–95 percentiles, horizontal line represents median, and whiskers represent minimum and maximum. *P<0.05.

Figure 3.

Percentage of Group B Streptococcus (GBS) invasive disease (sepsis and meningitis) in infants born to Crete the last 22 years. Data are categorized to early onset (0-6 days) or late onset (7-89 days) infections.