5/18/20151 Group B Streptococcus Group B Streptococcus Adunni Morohunfola, M.D. Dept. of Pediatrics, Texas Tech

5/18/20152 Etiolgy Group B streptococcus(Strep.agalactiae) Facultative encapsulated gram-positive diplococcus Produces a narrow zone of beta hemolysis on blood agar. Most strains are resistant to bacitracin and septrin Positive CAMP

5/18/20153 Etiology Divided into the following serotypes based on capsular polysacch. types Ia, Ib,II and III through VII. All serotypes can cause infections in newborns but Ia,II,III,V account for 90%. Late onset dx and early-onset meningitis is due to type III.

5/18/20154 Epidemiology Epidemiology Approx. 10%-35% of pregnant women are asymptomatic carriers of GBS in the genital and G. Intestinal tract. At birth 1 in 2 infants born to colonized mothers are colonized. 98% of colonized infants are without symptoms, but 1%-2% developed GBS. Nearly 50% of sexual partners of colonized women are colonized themselves.

5/18/20155 Epidemiology Epidemiology Incidence rate of 0.2 – 3.7/1000 live births. Mortality rate of 5-15/1000 live births. More recent surveillance shows a decrease in I.R to 0.8 per 1000 live births-reflection of use of maternal antibiotic prophylaxis. Incidence rate at Thomason: /1000 live births in /1000 live births in 2001.

5/18/20156 Incidence per 1000 live births of early-onset GBS disease at Thomason Hospital Data Source: Dept. of Pediatrics, Texas Tech

5/18/20157 Epidemiology Epidemiology Direct cost of treating neonate with proven GBS – 300 million dollars/year. Indirect costs: Mother’s prophylaxis? Baby‘s treatment for suspected sepsis?

5/18/20158 Transmission/ Incubation period. Vertical transmission: From mother to infant occurs shortly before or during delivery. After delivery, person-to-person transmission can occur via hand contamination. Incubation Period: – early onset disease is less than 6 days –late onset disease is unknown.

5/18/20159 Risk factors for Colonization Infants born < 37weeks Heavily colonized mothers PROM > 18 hrs. Intrapartum fever F Maternal chorioamnionitis GBS bacteruria Maternal age < 20yrs African American ethnicity

5/18/ Early onset vs. Late onset Occurs in 1st week. Usually before 72hrs Pathophysiology. -Colonization. -Immature host defense mech particularly among low birth wt infants. 1week to 6months. Usually at 3-4 weeks. Pathopysiology. - Related to initial colonization. - Alteration of the mucosa barrier by a viral resp tract inf.,weakened host defense,decrease amt of maternal antibodies.

5/18/ Early Onset Vs Late Onset Early Onset Vs Late Onset Transmission: -aquired thru vertical transmission. -ascending infection, duration of rupture of memb. directly proportional to I.R. -during passage thru a colonized birth canal. Transmission: -aquired thru horizontal transmission: -nurseries -hospital personnel -community

5/18/ Early Onset Vs Late onset Clinical Manifestation: -Pneumonia:respiratory distress, tachypnea cyanosis,hypoxaemia apnea -Pulmonary HTN -Shock -Poor feeding -Abnormal temperature -Less often meningitis Clinical manifestation: –Occult bacteremia, meningitis, ventriculitis, and other focal infections, e.g. septic arthritis, osteomyelitis.

5/18/ Laboratory Findings Identification of Gm +ve cocci in pairs and in chains in fluids that are sterile indicate invasive disease. - CSF,Blood,Pleural Fluid,Joint Fluid. Gm +ve cocci in gastric or tracheal aspirate,skin and mucous memb indicate colonization. Rapid antigen test in CSF. - rapid test that identify GBS antigen In other body fluids not recommended.

5/18/ LABORATORY fINDINGS Non specific tests -CBC ;Leukocytosis, Lt shift, increased band count, Increase I.T ratio >0.20,neutropenia, thrombocytopenia. -Incr. CRP. -Cxray showing pneumonia, atelectasis.

5/18/ Differential Diagnosis Sepsis Aspiration pneumonia(meconium) HMD Wet lung(TTNB) Total anomalous pulmonary venous return Poor inspiration film

5/18/ Treatment of GBS Drug of choice; when organism has been identified is Pen G. 200,000U/kg/day. Empirical Rx; Ampicillin + Gent. - used until GBS has been cultured. Also susceptible to: -V ancomycin -Cefotaxime -Ceftriaxone -Chloramphenicol

5/18/ Treatment Supportive care hypoxia- mechanical ventilation DIC-Fresh frozen plasma Seizures-antiseizure medication -Increased ICP SIADH-Fluid restriction

5/18/ Treatment of GBS Meningitis I.V Penicillin G -Infants 7days 300,000U/kg/day. I.V Ampicillin -Infants 7days 300mg/kg/day.

5/18/ Treatment of GBS Meningitis Repeat lumbar puncture hrs after initiation of Rx. Consultation with a specialist in pediatric I.D may be useful.

5/18/ Duration of Rx of GBS Bacteremia –10days. Uncomplicated meningitis –14days. Complicated meningitis -Requires prolonged course,guided by bacteriologic report. Osteomyelitis,ventriculitis-4weeks.

5/18/ Complications of GBS Complications of GBS Mortality rate ranges 5-15% highest in: –very low birth wt infants –Septic shock –Delay in instituting antimicrobial Rx.

5/18/ Complications of GBS Complications of GBS Neurological sequelae: –Mental retardation –Quadriplegia –Hemiplegia –Seizures –Cortical blindness –Bilateral deafness –Hydrocephalus –SIADH

5/18/ Control Measures Screening based Strategy: -All pregnant Offer prophylaxis to GBS carriers. If GBS onset of labor or ROM Rx. Risk factor based strategy: - Prevention based on presence of intrapartum risk factor without screening.

5/18/ Control Measures Important factors of maternal prophylaxis: –Administer intrapartum antibiotics 4 or more hrs before delivery –2 or more doses of Pen.G or Ampicillin.

5/18/ Guidelines Guidelines Empiric mgt of asymptomatic infants: –<35wks whose mom received antibiotic 2 or more doses: CBC,Bld Cx Observe for 48hrs without antibiotics. – >35wks whose mom received antibiotic 2 or more doses: No lab eval required Observe for 48hrs without antibiotics.

5/18/ Guidelines Empiric Mgt. (Contd.) –For infants > 35wks whose moms received 1 dose: May include CBC,CRP,Bld Cx Observe for 48hrs.

5/18/ Incidence rate (per 1000 live births) of early-onset GBS disease prior to use of IPC Data Source: CDC Publications/Thomason

5/18/ Incidence rate (per 1000 live births) of early-onset GBS disease by year and site Data Source: CDC Publications/Thomason

5/18/ Incidence rate (per 1000 live births) of early-onset GBS disease at Thomason Data Source: Dept. of Pediatrics, Texas tech

5/18/ Incidence Rate of EOGBS Disease vs. % of Hospitals with DX Prevention Policy

5/18/ Prognosis Of all survivors of early or late onset GBS meningitis: –25-50% have permanent neurological sequelae –1/3 of these patients will have severe blindness, deafness,and/or global developmental delay.