Burden of invasive group B Streptococcus disease in non-pregnant adults: A systematic review and meta-analysis

Abstract

Background Streptococcus agalactiae or group B Streptococcus (GBS) has emerged as an important cause of invasive disease in adults, particularly among the elderly and those with underlying comorbidities. Traditionally, it was recognised as an opportunistic pathogen colonising and causing disease in pregnant women, neonates, and young infants. Reasons for the upsurge of invasive GBS (iGBS) among the elderly remain unclear, although it has been related to risk factors such as underlying chronic diseases, immunosenescence, impaired inflammatory response, and spread of virulent clones. Antibiotics are successfully as treatment or prophylaxis against iGBS. Several candidate vaccines against iGBS are under development. Objectives To conduct a systematic review of the current literature on invasive GBS in order to determine disease incidence and case fatality ratio (CFR) among non-pregnant adults. Additionally, information on risk factors, clinical presentation, serotype distribution, and antimicrobial resistance was also retrieved. Methods Between January and June 2020, electronic searches were conducted in relevant databases: MEDLINE, EMBASE, Global Health, and SCOPUS. Studies were included in the systematic review if they met the inclusion/exclusion criteria. The authors assessed the selected studies for relevance, risk of bias, outcome measures, and heterogeneity. Meta-analyses on incidence and CFR were conducted after evaluating the quality of methods for assessment of exposure and outcomes. Results Pooled estimates of iGBS incidence in non-pregnant adults 15 years and older were 2.86 cases per 100.000 population (95% CI, 1.68–4.34). Incidence rates in older adults were substantially higher, 9.13 (95%CI, 3.53–17.22) and 19.40 (95%CI, 16.26–22.81) per 100.000 population ≥50 and ≥ 65 years old, respectively. Incidence rates ranged from 0.40 (95% CI, 0.30–0.60) in Africa to 5.90 cases per 100.000 population (95% CI, 4.30–7.70) in North America. The overall CFR was and 9.98% (95% CI, 8.47–11.58). CFR was highest in Africa at 22.09% (95% CI, 12.31–33.57). Serotype V was the most prevalent serotype globally and in North America accounting for 43.48% (n = 12926) and 46,72% (n = 12184) of cases, respectively. Serotype Ia was the second and serotype III was more prevalent in Europe (25.0%) and Asia (29.5%). Comorbidities were frequent among non-pregnant adult iGBS cases. Antimicrobial resistance against different antibiotics (i.e., penicillin, erythromycin) is increasing over time. Conclusions This systematic review revealed that iGBS in non-pregnant adults has risen in the last few years and has become a serious public health threat especially in older adults with underlying conditions. Given the current serotype distribution, vaccines including serotypes predominant among non-pregnant adults (i.e., serotypes V, Ia, II, and III) in their formulation are needed to provide breadth of protection. Continued surveillance monitoring potential changes in serotype distribution and antimicrobial resistance patterns are warranted to inform public health interventions.

Heterogeneity of the group B streptococcal type VII secretion system and influence on colonization of the female genital tract

“…As an opportunistic pathogen, GBS (or Streptococcus agalactiae ) asymptomatically resides in the gastrointestinal and/or female genital tract of 25-30% of healthy adults (Wilkinson, 1978, Regan et al ., 1991) but can cause severe infections in some individuals, such as pregnant people and newborns, the elderly, and patients living with cancer or diabetes (Nandyal, 2008, Pimentel et al ., 2016, Russell et al ., 2017, Patras & Nizet, 2018, van Kassel et al ., 2019, Navarro-Torne et al ., 2021). Within the female genital tract, GBS coexists and/or competes with the vaginal microbiota and, therefore, has evolved mechanisms to survive these encounters while also avoiding immune clearance (Okumura & Nizet, 2014, Vrbanac et al ., 2018, Coleman et al ., 2021).…”

Differential Interaction between Invasive Thai Group B Streptococcus Sequence Type 283 and Caco-2 Cells

“…A 12-year retrospective study from 2004 to 2015 obtained from two hospitals in Bangkok, Thailand, revealed that invasive GBS infections were higher among the elderly and middle-aged adults compared to neonates ( Figure S1 ). This reflects a potential health threat to older adults from GBS invasive disease [ 40 ]. There are five major CCs of human GBS circulating around the globe; CC1, CC10, CC17, CC19, and CC23 [ 18 ].…”

Invasive Streptococcus agalactiae Disease With Meningitis and Septic Arthritis in a Non-pregnant Patient

“…However, in some cases, it can present with bacteraemia in non-pregnant adults. Retrospective studies [ 2 , 3 ] and a recent meta-analysis [ 10 ] studied some factors predisposing to develop S. agalactiae infections and bacteraemia in non-pregnant adults, namely diabetes, malignancies, liver and renal disease and immunosuppressive disorders.…”