Table 1.2: Proportion of various syndromes caused by GBS from epidemiological data
Syndrome	Identifying ICD-10-CA codes	Proportion caused by GBS	References
Infant disease
Early onset neonatal infection (0-6d)	P36	16%	Cohen-Wolkoweiz et al 200928: Looked retrospectively at cases of blood culture confirmed early onset neonatal sepsis, defined as < 3d of age, in neonatal ICUs in the United States in late preterm infants; found 120/531 cases of early onset cases to be culture positive for GBS
			Stoll et al 201129: Looked prospectively at culture confirmed early onset sepsis and early onset meningitis cases in a cohort of 400,000 live births under 72h of age in the US 2006 to 2009; found 159 out of 370 confirmed cases of sepsis to be caused by GBS, or 167/611 if one considers sepsis and meningitis and includes those cultures where the organism was considered a contaminant or contained solely coagulase negative staph. All infants in the study were treated with ≥ 5 days antibiotics or died on antibiotics at < 5d.
Late onset neonatal infection	Sepsis codes for infants 3d to 90d of age	5% based on all numbers including the low birth weight infants; 12% based on all numbers excluding the low birth weight papers; 22% according to the Cantey review	Cohen-Wolkoweiz et al 200928: Looked retrospectively at cases of culture confirmed late onset neonatal sepsis, defined as 4–120 days of age, in neonatal ICUs in the United States in late preterm infants; found 26/803 cases of early onset cases to be culture positive for GBS
			Stoll et al 200230: looked retrospectively at culture confirmed LOS in very low birth weight infants in the US 1998–2002; found 30/1313 blood culture positive cases to be caused by GBS
			Byington et al 20033: Retrospectively looked at infants up to 90d of age on Salt Lake City, Utah, 1999 to 2002 with fever; found 6/105 blood culture positive cases to be GBS, out of 1298 infants who were evaluated for fever and had not had antibiotics in the preceding 24 hours and “Approximately 1800” evaluated for fever
			Biondi et al 20133: Retrospectively looked at 3-90d old infants in the US, mainly NYC, and found 41/181 blood culture positive cases to be positive for GBS
			Greenhow et al 20143: Retrospectively analysed blood, urine and CSF 2005 to 2011 a t a hospital in ne California on full term previously healthy infants aged 1 week to 3 months; 23/129 cases of bacteraemia (18%) were GBS.
			Watt et al 201034: Retrospective review of 668 infants with fever without localising source ≤ 90d 1997 to 2006 (in 2 5y blocks). Out of 20 and 52 patients with serious infections evaluated by culture, 5 (25%) and 1 (1.9%) had GBS, or 6/668 of infants evaluated for fever without localising source.
			Ashkenazi-Hoffnung et al 201135: GBS was found to cause 1/151 culture positive cases of fever, or 1/1584 cases of fever before evaluation of culture, in children under 90 days old, studied 2005 to 2009 in Israel
			Cantey et al 201536: retrospective study in Dallas looking at all lab confirmed sepsis on children under 60 days of age May 2011 to December 2013; 30/265 cases associated with GBS (11.3%)
			Cantey et al 20163: a review including the seven papers above; they aggregate the data to say that 22% of cases of bacteraemia in 529 infants ≤ 90d was caused by GBS
Childhood meningitis	G00, G01	< 1m: 18% 1m to < 3m: 39%. 3m to < 3y: 11%. 3y to < 10y: 5%. 10y to 19y: 8%.	Nigrovic et al 200837: looked at 231 cases of lab confirmed meningitis (by CSF culture,, blood culture or CSF latex agglutination) in the US in children 1m to 19y; found total 42 of 231 CSF cultures GBS positive, divided by age as given.
			Stoll et al 201129: Looked prospectively at culture confirmed early onset sepsis and early onset meningitis cases in a cohort of 400,000 live births in the US 2006 to 2009 for infants < 3d; found 3 out of 16 confirmed cases of meningitis to be caused by GBS.
Congenital pneumonia	P23	-	No epidemiological data including GBS available
Maternal disease
Maternal sepsis/Puerperal fever	O75.3, O85	Antepartum 9.7%; postpartum 7.4%	Acosta et al 201438: Looked at pregnant women in the UK with clinical sepsis (including those in whom there was no eventual confirmation by lab testing or in which the organism remained unknown). 13/134 and 17/231 women with pre and postpartum sepsis had GBS on culture respectively.
Chorioamnionitis	O23.5, O42.11, O42.12, O42.13, O42.19	-	No epidemiological data available
Septic abortion	O03.0, O03.5	-	No epidemiological data available
Stillbirth	P95	0 – 12.1%; 2.3%	Nan et al 201539: Systematic review of stillbirth puts the proportion associated with GBS infection to be 0–12.1%, with the most recent US paper available giving 2.3%
All patient groups (data mostly from non-pregnant adults)
Cellulitis and soft tissue infection	L03	0.6%	Noel et al 200840: Multicentre study in the US identifying complicated skin and soft tissue infections in > 18 year olds caused by confirmed or suspected gram positive bacteria in multiple countries between October 2004 and December 2005. Ten out of 784 detected cases before microbiological evaluation were caused by GBS (70 by gram negative infections).
			Jones et al 20034: Used retrospective data from The Surveillance Network to look at culture confirmed skin and soft tissue infections in the USA and EU through the entirety of 2001; found GBS to cause 92/26233 cases registered in the USA and 434/58865 in the EU.
Bacteraemia without focus	A40, A41, A42.7, A22.7, B37.7, A26.7, A28.2, A54.86, A32.7, A39.2, A39.3, A39.4, A21.7, R57.2, A48.3, A02.1, R65.1	1%	Diekema et al 20024: Study using North American SENTRY programme to identify 25,745 culture positive bloodstream infections January 1997 to 2000; found 922 (3.6%) to be caused by beta haemolytic streptococci.
			Lark et al 20014: Seattle study collecting data on blood culture positive community acquired bacteraemia 1994 to 1997; found 8/387 episodes to be caused by beta haemolytic strep
			Rantala et al 20094: Study in Pirkanmaa, India looking at sensitivity of different beta haemolytic strep to antibodies, using blood stream infection samples. Showed than 76/314 cases of bloodstream infection cultured were due to GBS. This proportion can be used to modify the percentage of beta haemolytic strep causing bacteraemia in the above study to estimate the burden of GBS.
Osteomyelitis	M86	4%	Goergens et al 200545: Australian study looking at one hospital 1998-2002, found GBS to account for 2/102 cases of acute haematogenous osteomyelitis in patients less than 16 years of age from January 1998 to June 2002
Urinary tract infections	N10, N30.0	10% for pyelonephritis in pregnancy; 2% of UTIs	Imirzalioglu et a 200846: Analysed 1613 urine samples from patients in Giessen, Germany with culture and PCR. 5/165 of those in which an infection was identified (3%) contained GBS
			Laupland et al 20074, Study which 40618 UTI samples 2004–2005 in Calgary, Canada, in which organisms could be identified; of the ambulatory patients, 2.% had GBS; inpatients 4.9%; nursing home residents, 2.0%. Reviewed, with excellent visualisations of the data, in Foxman 2010.8
			Ulett at al 200949: Looked for GBS in the urine of 34367 patients >18 with clinically suspected UTI in Birmingham house hospital, University of Alabama. 387 (1.1%) had GBS in their urine.
			Bouza et al 200150: One day point prevalence questionnaire in multiple European hospitals 29th February 2000 asking about lab confirmed nosocomially acquired UTIs. Identified 522; in the EU, GBS was not reported as a cause, but in non-EU countries, GBS accounted for 1.6% of cases.
			Jones et al 19995: Looked at organisms from 1698 cases of lab confirmed UTI (1308 US; 390 Canada) Jul-Sep 1997; beta haemolytic strep accounted for 1.2% of the total.
			Mathai et al 20015: Looked at organisms from 1510 cases of lab confirmed UTI in the US and Canada, 1998, 9 of which were GBS (0.6%)
			Grude et al 20015: Looked at 52350 urine samples processed in Norway June 1997 to October 1999, 28066 of which had bacteria present; of these, inpatient samples revealed 0.8% to contain GBS (41/53252) and outpatients outpatients 1.5% (349/22714)
			Flores-Mireles et al 20155: Nature Microbiology Review with a figure citing GBS as the cause of 3% of uncomplicated UTI and 2% of complicated UTI.
			Zhanel et al 20005: Collected 2000 UTI isolates from 10 tertiary care Canadian hospitals Jan-Sep ’98, and found 0.5% (10) to contain GBS.
Peritonitis	K65.0	?	No epidemiological data available
Septic arthritis	M00	13% of children <16; 14% adults	Goergens et al 200545: Australian study looking at clinical cases of septic arthritis in patients <16 years of age in one hospital 1998-2002; found GBS to account for 1/47 of septic arthritis in children.
			Bono et al 201556: Retrospectively looked at cases of septic arthritis in children younger than three months in a hospital in Ohio from 1994 to 2010; identified 14 cases, 5 of which were positive for GBS on aspirate or blood culture.
			Binard et al 200657: Retrospectively identified cases of septic arthritis in patients of any age in Brest Hospital, France between May 2000 and May 2004; Analysed 48 patients with septic arthritis and found 5 (10.4%) of the cases were caused by group B streptococcus
			Nolla et al 200358: Collected all microbiologically proven cases of septic arthritis in patients over 20 years of age, January 1992 to December 2001 in a hospital in Barcelona; found 11/112 patients cases to be associated with GBS infection
			Louthrenoo et al 201459: A study looking retrospectively at 244 septic arthritis patients in Thailand between July 1990 and December 2010, finding 38 (15.57%) to be caused by GBS
Meningitis	G00. G01	2%	Domingo et al 199760: Isolated GBS from 12/278 (4.3%) cases of clinically diagnosed acute bacterial meningitis in patients over 15 years of age 1982 to 1996 in Barcelona and Terrassa .
			Van de Beek et al 20046: Study looking at 683 patients >16 yoa in the Netherlands 1998 to 2002 with culture confirmed acute bacterial meningitis; 5 were due to GBS (0.73%)
Endocarditis	I33.0	1.70%	Sambola et al 20026: Study in 4 Spanish hospitals 1975 to 1998 describing 1771 episodes of endocarditis in patients over 18 years, finding 30 to be caused by GBS.
Endophthalmitis	H44.0	5–10%	Durand 20176: Review paper; states 9% of infectious endophthalmitis is caused by streptococci.
			Jackson et al 20036: Prospectively in St Thomas’ Hospital, London, and through literature search identified culture positive cases of endogenous bacterial endopthalmitis from 1986 to 2001. 4/19 prospectively identified cases and 14/267 review cases were caused by GBS.
Pneumonia	J10.0, J11.0, J12, J13, J14, J15, J16, J17, J18,	?	No epidemiological data including GBS available
Pericarditis/myocarditis	I301, I400	?	No epidemiological data including GBS available
Unspecified bacterial infection	A49.1, A49.9	NA	Initially included in search but later decided to be too non-specific to be useful