Group B Streptococcal Infections PDF

762 GROUP B STREPTOCOCCAL INFECTIONS tests as harboring GAS organisms....

762 GROUP B STREPTOCOCCAL INFECTIONS tests as harboring GAS organisms. Household contacts of patients with severe invasive GAS disease, including STSS, are at some increased risk of developing severe invasive GAS disease compared with the gen- eral population. However, the risk is not sufficiently high to warrant routine testing for GAS colonization, and a clearly effective regimen has not been identified to justify rou- tine chemoprophylaxis of all household contacts. However, because of increased risk of sporadic, invasive GAS disease among certain populations (eg, people with human im- munodeficiency virus [HIV] infection) and because of increased risk of death in people 65 years and older who develop invasive GAS disease, physicians may choose to offer target- ed chemoprophylaxis to household contacts who are 65 years and older or who are members of other high-risk populations (eg, people with HIV infection, varicella, or dia- betes mellitus). Because of the rarity of secondary cases and the low risk of invasive GAS infections in children, chemoprophylaxis is not recommended in schools or child care All rights reserved. May not be reproduced in any form without permission from the publisher, except fair uses permitted under U.S. or applicable copyright law. facilities. Bacterial Endocarditis Prophylaxis. 1 The American Heart Association (AHA) has published updated recommendations regarding use of antimicrobial agents to prevent infective en- docarditis (see Prevention of Bacterial Endocarditis, p 1044). The AHA no longer rec- ommends prophylaxis for patients with rheumatic heart disease without a prosthetic valve. However, use of oral antiseptic solutions and maintenance of optimal oral health through daily oral hygiene and regular dental visits remain important components of an overall health care program. For individuals with a prosthetic valve, infective endocarditis prophylaxis still is recommended, and current AHA recommendations should be fol- lowed. If penicillin has been used for secondary prevention of rheumatic fever, an agent other than penicillin should be used for infective endocarditis prophylaxis, because peni- cillin-resistant alpha-hemolytic streptococci are likely to be present in the oral cavity of such patients. Group B Streptococcal Infections CLINICAL MANIFESTATIONS: Group B streptococci are a major cause of perinatal infec- tions, including bacteremia, endometritis, intra-amniotic infection (formerly called chori- oamnionitis), and urinary tract infections in women during pregnancy and immediately postpartum, and of systemic and focal infections in neonates and young infants. Invasive disease in infants is categorized on the basis of chronologic age at onset. Early-onset dis- ease usually occurs within the first 24 hours of life (range, 0 through 6 days) and is charac- terized by signs of systemic infection, respiratory distress, apnea, shock, pneumonia, and less often, meningitis (5%–10% of cases). Late-onset disease, which typically occurs at 3 to 4 weeks of age (range, 7 through 89 days), commonly manifests as occult bacteremia or meningitis (approximately 30% of cases); other focal infections, such as osteomyelitis, sep- Copyright 2018. American Academy of Pediatrics. tic arthritis, necrotizing fasciitis, pneumonia, adenitis, and cellulitis, occur less commonly. Nearly 50% of survivors of early- or late-onset meningitis have long-term neurologic se- quelae (encephalomalacia, cortical blindness, cerebral palsy, visual impairment, hearing 1 Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective endocarditis. Recommendations by the Amer- ican Heart Association. A guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007;116(15):1736–1754 EBSCO Publishing : eBook Academic Collection (EBSCOhost) - printed on 8/17/2021 6:25 AM via UNIV OF SOUTH ALABAMA AN: 1809323 ; Kimberlin, David W., Brady, Michael T., Jackson, Mary Anne, Long, Sarah S..; Red Book 2018 : Report of the Committee on Infectious Diseases Account: s4595122.main.emed  GROUP B STREPTOCOCCAL INFECTIONS 763 deficits, or learning disabilities). Late, late-onset disease occurs at 90 days of age and be- yond, usually in very preterm infants requiring prolonged hospitalization. Group B strep- tococci also cause systemic infections in nonpregnant adults with underlying medical con- ditions, such as diabetes mellitus, obesity, chronic liver or renal disease, malignancy, or other immunocompromising conditions and in adults 65 years and older. ETIOLOGY: Group B streptococci (Streptococcus agalactiae) are gram-positive, aerobic diplo- cocci that typically produce a narrow zone of beta hemolysis on 5% sheep blood agar. These organisms are divided into 10 types on the basis of capsular polysaccharides (Ia, Ib, and II through IX). Types Ia, Ib, II, III, and V account for approximately 95% of cases in infants in the United States, with type IV emerging as an important cause of invasive infections in adults. Type III is the predominant cause of early- and late-onset meningitis and the majority of late-onset infections in infants. Capsular polysaccharides and pilus- like structures are important virulence factors and are potential vaccine candidates. EPIDEMIOLOGY: Group B streptococci are common inhabitants of the human gastrointestinal and genitourinary tracts. Less commonly, they colonize the pharynx. The colonization rate in pregnant women ranges from 15% to 35%. Colonization during pregnancy can be constant or intermittent. Before recommendations were made for pre- vention of early-onset group B streptococcal (GBS) disease through maternal intrapartum antimicrobial prophylaxis (see Control Measures, p 765), the incidence was 1 to 4 cases per 1000 live births; early-onset disease accounted for approximately 75% of cases in in- fants and occurred in approximately 1 to 2 infants per 100 colonized women. Following widespread implementation of maternal intrapartum antimicrobial prophylaxis, the inci- dence of early-onset disease has decreased by approximately 80% to an estimated 0.25 cases per 1000 live births in 2014. The use of intrapartum chemoprophylaxis has had no measurable effect on late-onset GBS disease. In recent years, the incidence of late-onset disease has nearly equaled that of early-onset disease. The case-fatality ratio in term in- fants ranges from 1% to 3% but is higher in preterm neonates (estimated to be 20% for early-onset disease and 5% for late-onset disease). Approximately 70% of early-onset and 50% of late-onset cases afflict term neonates. Transmission from mother to infant occurs shortly before or during delivery. After delivery, person-to-person transmission can occur. Although uncommon, GBS infection can be acquired in the nursery from health care professionals (probably resulting from omissions in hand hygiene) or visitors and more commonly in the community (colonized family members or caregivers). The risk of early-onset disease is increased in preterm in- fants (less than 37 weeks’ gestation), infants born after the amniotic membranes have been ruptured 18 hours or more, and infants born to women with high genital GBS inoculum, intrapartum fever (temperature 38°C [100.4°F] or greater), intra-amniotic infection (for- merly called chorioamnionitis), GBS bacteriuria during the current pregnancy, or a pre- vious infant with invasive GBS disease. A low or an undetectable maternal concentration of type-specific serum antibody to capsular polysaccharide of the infecting strain also is a predisposing factor for neonatal infection. Other risk factors are intrauterine fetal moni- toring and maternal age younger than 20 years. Black race is an independent risk factor for both early-onset and late-onset disease. Although the incidence of early-onset disease has declined in all racial groups since the 1990s, rates consistently have been higher among black infants (0.54 cases per 1000 live births in 2014) compared with white infants (0.18 cases per 1000 live births), with the highest incidence observed among preterm black infants (0.96 per 1000 live births in 2014). The reason for this racial/ethnic EBSCOhost - printed on 8/17/2021 6:25 AM via UNIV OF SOUTH ALABAMA. All use subject to https://www.ebsco.com/terms-of-use  764 GROUP B STREPTOCOCCAL INFECTIONS disparity is not known. The period of communicability is unknown but can extend throughout the duration of colonization or disease. Infants can remain colonized for sev- eral months after birth and after treatment for systemic infection. Recurrent GBS disease affects an estimated 1% to 3% of appropriately treated infants. The incubation period of early-onset disease is fewer than 7 days. In late-onset and late, late-onset disease, the incubation period from GBS acquisition to disease is unknown. DIAGNOSTIC TESTS: Visualization of Gram-positive cocci in pairs or short chains by Gram stain of body fluids that typically are sterile (eg, cerebrospinal fluid [CSF], pleural fluid, or joint fluid) provides presumptive evidence of infection. Growth of the organism from cultures of blood, CSF, or if present, a suppurative focus is necessary to establish the diagnosis. A meningitis/encephalitis multiplex panel polymerase chain reaction assay cleared by the US Food and Drug Administration (FDA) is approved for direct testing of CSF and detection of GBS along with many other bacterial, viral, and fungal pathogens. Clinical experience with this multiplex assay is limited. For prenatal GBS screening, vagi- nal and rectal swab maternal specimens are collected and enriched in commercially available selective broth mediums for 18 to 24 hours at 35°C to 37°C in ambient air or 5% carbon dioxide and subsequently plated on tryptic soy blood agar or other selective agars for further 24 to 48 hour incubation and isolation. Alternatively, DNA probe assays, latex agglutination assays, and nucleic acid amplification assays are available to detect GBS from enriched broth specimens. One of these FDA-cleared molecular assays also is approved for intrapartum detection of GBS from vaginal/rectal swab specimens collected from pregnant women presenting in labor if GBS colonization is unknown. TREATMENT: Ampicillin plus an aminoglycoside is the initial treatment of choice for a newborn in- fant with presumptive early-onset GBS infection. For empirical therapy of late-onset meningitis, ampicillin and an aminoglycoside or cefotaxime are recommended. If the infant is 2 months or older, vancomycin and ceftriaxone are recommended to ensure that therapy would be appropriate for Streptococcus pneumoniae meningitis until results of cultures confirm GBS. Penicillin G alone is the drug of choice when GBS has been identified as the cause of the infection and when clinical and microbiologic responses have been documented. Ampicillin is an acceptable alternative therapy. For infants with meningitis attributable to GBS, the recommended dosage of penicillin G for infants 7 days or younger is 250 000 to 450 000 U/kg per day, intravenously, in 3 divided doses; for infants older than 7 days, 450 000 to 500 000 U/kg per day, intra- venously, in 4 divided doses is recommended. For ampicillin, the recommended dos- age for infants with meningitis 7 days or younger is 200 to 300 mg/kg per day, intra- venously, in 3 divided doses; the recommended dosage for infants older than 7 days is 300 mg/kg per day, intravenously, in 4 divided doses. For meningitis, especially in the neonate, some experts recommend a second lumbar puncture be performed approximately 24 to 48 hours after initiation of therapy to as- sist in management and prognosis. If CSF sterility is not achieved, a complicated course (eg, cerebral infarcts, cerebritis, ventriculitis) can be expected; an increasing protein concentration suggests an intracranial complication (eg, infarction, subdural empyema, ventricular obstruction). Additional lumbar punctures are indicated if response to therapy is in doubt, neurologic abnormalities persist, or focal neurologic EBSCOhost - printed on 8/17/2021 6:25 AM via UNIV OF SOUTH ALABAMA. All use subject to https://www.ebsco.com/terms-of-use  GROUP B STREPTOCOCCAL INFECTIONS 765 deficits occur. Failed hearing screen, abnormal neurologic examination, and certain cranial imaging abnormalities at discharge predict an adverse long-term outcome. Consultation with a specialist in pediatric infectious diseases can assist in treatment of all cases of neonatal meningitis including GBS. For infants with bacteremia without a defined focus, treatment should be continued for 10 days. For infants with uncomplicated meningitis, 14 days of treatment is satis- factory, but longer periods of treatment may be necessary for infants with prolonged or complicated courses. Septic arthritis or osteomyelitis requires treatment for 3 to 4 weeks; endocarditis or ventriculitis requires treatment for at least 4 weeks. Treatment should be administered exclusively by the parenteral route. Because of the reported increased risk of infection, the birth mates of a multiple birth index case with early- or late-onset disease should be observed carefully and evaluated and treated empirically for suspected systemic infection if signs of illness occur; treat- ment should be continued for a full course for those with confirmed infection. ISOLATION OF THE HOSPITALIZED PATIENT: Standard precautions are recommended, except during a nursery outbreak of disease attributable to group B streptococci (see Con- trol Measures, Nursery Outbreak). CONTROL MEASURES: Chemoprophylaxis. Recommendations from the Centers for Disease Control and Preven- tion (CDC) 1 and American Academy of Pediatrics 2 have been incorporated into a smart phone app (www.cdc.gov/groupbstrep/guidelines/prevention-app.html) and include the following: All pregnant women should have culture screening at 35 to 37 weeks’ gestation for vaginal and rectal GBS colonization. For women who present with preterm labor, GBS screening should be performed and parenteral GBS prophylaxis should be initi- ated. If delivery occurs within 5 weeks and the prior screening result was negative, then no further testing is needed. For those who present >5 weeks after initial preterm labor, then rescreening and management according to the algorithm in the references below is recommended. For women who had a previous infant with invasive GBS disease, intrapartum chem- oprophylaxis always should be administered. Women with group B streptococci isolated from urine during the current pregnancy should receive intrapartum chemoprophylaxis, because these women usually have a high inoculum of group B streptococci at vaginal and rectal sites and are at increased risk of delivering an infant with early-onset GBS disease; culture screening at 35 to 37 weeks’ gestation is not necessary if GBS is isolated from the urine prior to screening. Intrapartum chemoprophylaxis should be given to all pregnant women identified as GBS carriers in the index pregnancy. Colonization during a previous pregnancy is not an indication for intrapartum chemoprophylaxis. If GBS status is not known at onset of labor or rupture of membranes, intrapartum chemoprophylaxis should be administered to all women with gestation less than 37 weeks, duration of membrane rupture 18 hours or longer, or intrapartum temperature 1Centers for Disease Control and Prevention. Prevention of perinatal group B streptococcal disease. Revised guidelines from CDC, 2010. MMWR Recomm Rep. 2010;59(RR-10):1–36 2 American Academy of Pediatrics, Committee on Infectious Diseases. Recommendations for the prevention of perinatal group B streptococcal (GBS) disease. Pediatrics. 2011;128(3):611–616 EBSCOhost - printed on 8/17/2021 6:25 AM via UNIV OF SOUTH ALABAMA. All use subject to https://www.ebsco.com/terms-of-use  766 GROUP B STREPTOCOCCAL INFECTIONS of 38.0°C (100.4°F) or greater. Oral antimicrobial agents should not be used to treat women who are found to have GBS colonization during culture screening. If there is GBS bacteriuria, treatment is warranted according to obstetric standards of care. Such treatment is not effective in eliminating carriage of group B streptococci or preventing neonatal disease. Intrapartum antimicrobial prophylaxis is not recommended for cesarean deliveries performed before labor onset in women with intact amniotic membranes. Women ex- pected to undergo cesarean deliveries should undergo routine culture screening, be- cause onset of labor or rupture of membranes can occur before the planned cesarean delivery, and in this circumstance, intrapartum antimicrobial prophylaxis is recom- mended if the culture screen is positive. Intravenous penicillin G (5 million U initially, then 2.5 to 3.0 million U, every 4 hours, until delivery) is the preferred agent for intrapartum chemoprophylaxis because of its efficacy and narrow spectrum of antimicrobial activity. An alternative drug is intravenous ampicillin (2 g initially, then 1 g every 4 hours until delivery). Penicillin-allergic women without a history of anaphylaxis, angioedema, respiratory distress, or urticaria following administration of a penicillin should receive intravenous cefazolin (2 g initially, then 1 g every 8 hours). Cefazolin is recommended because of its ability to achieve high amniotic fluid concentrations and effectively prevent early- onset GBS disease. Penicillin-allergic women at high risk of anaphylaxis should receive intravenous clindamycin (900 mg every 8 hours) if their GBS isolate is documented to be suscepti- ble to clindamycin and erythromycin. If the isolate is sensitive to clindamycin but re- sistant to erythromycin, clindamycin may be used if testing for inducible clindamycin resistance is negative. Approximately 33% (40% if inducible resistance is included) of GBS isolates in the United States were clindamycin resistant in 2014, and the propor- tion may vary by country. If clindamycin susceptibility testing has not been performed or if the organism is resistant, intravenous vancomycin (1 g every 12 hours) should be administered. The efficacy of clindamycin or vancomycin in preventing early-onset GBS disease is not established. Routine use of antimicrobial agents as chemoprophylaxis for neonates born to moth- ers who have received adequate intrapartum chemoprophylaxis is not recommended. Antimicrobial therapy is appropriate only for infants with clinically suspected systemic infection. An algorithm for management of newborn infants is provided in Fig 3.9. The recom- mendations are intended to help clinicians promptly detect and treat cases of early- onset GBS infections. Newborn infants with signs of sepsis should receive a full diagnostic evaluation and initiation of empiric antimicrobial therapy. Well-appearing newborn infants whose mothers had suspected intra-amniotic infection (formerly called chorioamnionitis) should undergo a limited evaluation (includes a blood culture and complete blood cell count with differential and platelet counts). Consultation with obstetric providers is important to determine the level of clinical suspicion for intra-amniotic infection. Infants born to women for whom there is a high level of concern for intra-amniotic infection should receive empirical antimicrobial therapy pending culture results. EBSCOhost - printed on 8/17/2021 6:25 AM via UNIV OF SOUTH ALABAMA. All use subject to https://www.ebsco.com/terms-of-use  GROUP B STREPTOCOCCAL INFECTIONS 767 Fig 3.9. Management of Neonates for Prevention of Early-Onset Group B Streptococcal (GBS) Disease a Full diagnostic evaluation includes complete blood cell (CBC) count with differential, platelets, blood culture, chest radiograph (if respiratory abnormalities are present), and lumbar puncture (if patient stable enough to tolerate procedure and sepsis is suspected). b Antimicrobial therapy should be directed toward the most common causes of neonatal sepsis, including GBS and other organ- isms (including gram-negative pathogens), and should take into account local antimicrobial resistance patterns. c Consultation with obstetric providers is important to determine the level of clinical suspicion for chorioamnionitis (now known as intra-amniotic infection). Intra-amniotic infection is diagnosed clinically, and some of the signs are nonspecific. d Limited evaluation includes blood culture (at birth) and CBC count with differential and platelets (at birth and/or at 6–12 hours of life). e GBS prophylaxis indicated if one or more of the following: (1) mother GBS positive at 35 to 37 weeks’ gestation; (2) GBS status unknown with one or more intrapartum risk factors, including