Although infant deaths from group B streptococcus (GBS) infections declined 80% since the introduction of Centers for Disease Control and Prevention guidelines in 1996, they are still the leading causes of neonatal fatalities.1,2 Early-onset (first week of life) and late-onset (7-90 days after birth) GBS infections occur in 0.28 and 0.25 per 1000 cases, respectively.2 The 2 most frequent consequences of GBS infections are head and neck cellulitis and necrotizing fasciitis (NF), usually involving the skin and soft tissue.2
In infants, cellulitis usually manifests on the face because the oral mucosa is thought to be a source of colonization. In addition to GBS, other infections leading to cellulitis in infants include group A streptococcus and Staphylococcus aureus.2 The initial presentation of cellulitis includes irritability, edema, and erythema.2 Most cellulitis cases are treated with penicillin.2
NF in infants appears as omphalitis, mammitis, or balanitis.2 The causative pathogens are usually polymicrobial (Gram negatives, Staphylococcal species, and anaerobic organisms), so these infections are typically treated with broad-spectrum antibiotics.2 Similar to cellulitis, the presentation includes soft tissue erythema.2 Antibiotics and surgical debridement of the soft tissue are the usual treatments.
“Prompt recognition of cellulitis, and especially NF, is important with systemic intravenous antibiotics,” said Stanford T. Shulman, MD, professor of pediatrics at Northwestern University Feinberg School of Medicine in Chicago, Illinois, and an editorial advisory board member for Infectious Disease Advisor. “NF often requires life-saving surgical debridement in neonates as well as in older patients.”
Prevention Guidelines Save Lives
The CDC’s GBS infection guidelines focus on prevention. The universal recommendation is for all pregnant women to be tested for GBS colonization in the rectum and vagina at 35 to 37 weeks to avoid mother-to-infant transmission.1 Women who colonize GBS are more than 25 times more likely than women without positive cultures to deliver an infant who will be infected with early-onset GBS.1 When the CDC recommended intrapartum antibiotic prophylaxis for women who tested positive for GBS, the incidence of early-onset GBS infections dropped dramatically.1
Despite the CDC’s universal testing recommendations, clinicians should also be aware of other risk factors for early-onset GBS: prematurity, premature rupture of membranes, immunocompromised status, previous antibiotic use, African-American race, previous infantile GBS, and maternal age <20 years.2 In a literature search by Wojtera and colleagues, of the 40 infant cases they reviewed, 98% were late-onset, 65% were boys, and 58% were premature.
Rapid Testing Speeds the Right Treatment
Although strict implementation of the CDC guidelines has saved lives, more could be done to swiftly detect and treat infants who present with GBS leading to sepsis, cellulitis, and other rapidly developing infections.3 The current gold standard for infection detection in neonates is cerebrospinal fluid (CSF) cultures, but they take days to identify the correct pathogen to guide treatment.3
Arora and colleagues obtained 62 CSF samples of suspected bacterial meningitis in infants (0-3 months) with the FilmArray Meningitis/Encephalitis (ME) PCR Panel and compared results with the standard CSF cultures.3 The ME PCR panel identified 12 positive CSF samples from 9 infants: 10 GBS and 2 Escherichia coli vs 5 that tested positive by culture.3
The ME PCR panel identified the 7 CSF samples from infants who had previous antibiotic therapy.3 The PCR assay detects 14 pathogens that cause central nervous system infections (6 bacteria, 7 viruses, and 1 yeast) in approximately 1 hour compared with CSF cultures that can take a day.3 Although the ME PCR assay can more quickly identify the causative pathogens than can traditional CSF cultures, it cannot identify all possible causes of central nervous system infections, such as West Nile virus.3 The ME PCR panel can, however, provide rapid testing of infants who had previously tested negative because of prior antibiotic therapy.3
“Clinicians are now ordering this test on a case-by-case basis, especially if there is treatment of the patient before a spinal tap is done, CSF cultures are negative, and bacterial etiology is strongly suspected,” explained lead author Harbir Singh Arora, MD, pediatric infectious disease specialist at the Children’s Hospital of Michigan in Detroit. “There is no specific protocol, but [the test] is ordered based on clinical judgement.”
Vaccine to the Rescue?
“CDC recommendations for preventing neonatal GBS infections are very important, but they only prevent early-onset GBS infection (first 7 days if life),” said Dr Shulman. “Cellulitis and NF are almost exclusively late-onset infections. No other measures are known to prevent them. Thus, a GBS vaccine is needed.”
Although phase 1 and 2 trials of GBS vaccines have been completed, no GBS vaccine has been licensed.4 As such, the World Health Organization has called on researchers to develop a vaccine with a safety record similar to that of the influenza vaccine that could be administered to pregnant women in the second or third trimester.5
Summary and Clinical Applicability
GBS infections in infants (cellulitis and necrotizing fasciitis), although uncommon in infants, requires swift treatment with antibiotics, and occasionally surgical debridement. Although infant deaths from GBS infections declined 80% since the introduction of Centers for Disease Control and Prevention guidelines in 1996, they are still the leading causes of infectious neonatal fatalities.1,2 Risk factors such as prematurity, immunocompromised state, prior antibiotic use, and maternal GBS should alert clinicians to consider these differential diagnoses.
- Committee on Infectious Diseases; Committee on Fetus and Newborn, Baker CJ, Byington CL, Polin RA. Policy statement—Recommendations for the prevention of perinatal group B streptococcal (GBS) disease. Pediatrics. 2011;128(3):611-616.
- Wojtera M, Cheng H, Fiorini K, Coughlin K, Barton M, Strychowsky J. Group B streptococcal cellulitis and necrotizing fasciitis in infants: a systematic review [published online February 7, 2018]. Pediatr Infect Dis J. doi: 10.1097/INF.0000000000001931
- Arora HS, Asmar BI, Salimnia H, Agarwal P, Chawla S, Abdel-Haq N. Enhanced identification of Group B Streptococcus and Escherichia coli in young infants with meningitis using the Biofire FilmArray Meningitis/Encephalitis Panel. Pediatr Infect Dis J. 2017;36(7):685-687.
- Centers for Disease Control and Prevention. Prevention of perinatal group B Streptococcal disease revised guidelines from CDC, 2010. Morb Mortal Wkly Rep. 2010;59(RR10):1-36.
- World Health Organization. WHO preferred product characteristics for group B streptococcus vaccines. 2017. Published 2017. Accessed March 22, 2018.