Items in AFP with MESH term: Streptococcal Infections
Pharyngitis - Article
ABSTRACT: Sore throat is one of the most common reasons for visits to family physicians. While most patients with sore throat have an infectious cause (pharyngitis), fewer than 20 percent have a clear indication for antibiotic therapy (i.e., group A beta-hemolytic streptococcal infection). Useful, well-validated clinical decision rules are available to help family physicians care for patients who present with pharyngitis. Because of recent improvements in rapid streptococcal antigen tests, throat culture can be reserved for patients whose symptoms do not improve over time or who do not respond to antibiotics.
ABSTRACT: Group B streptococcus (GBS) is a leading cause of morbidity and mortality among newborns. Universal screening for GBS among women at 35 to 37 weeks of gestation is more effective than administration of intrapartum antibiotics based on risk factors. Lower vaginal and rectal cultures for GBS are collected at 35 to 37 weeks of gestation, and routine dindamycin and erythromycin susceptibility testing is performed in women allergic to penicillin. Women with GBS bacteriuria in the current pregnancy and those who previously delivered a GBS-septic newborn are not screened but automatically receive intrapartum antibiotics. Intrapartum chemoprophylaxis is selected based on maternal allergy history and susceptibility of GBS isolates. Intravenous penicillin G is the preferred antibiotic, with ampicillin as an alternative. Penicillin G should be administered at least four hours before delivery for maximum effectiveness. Cefazolin is recommended in women allergic to penicillin who are at low risk of anaphylaxis. Clindamycin and erythromycin are options for women at high risk for anaphylaxis, and vancomycin should be used in women allergic to penicillin and whose cultures indicate resistance to clindamycin and erytbromycin or when susceptibility is unknown. Asymptomatic neonates born to GBS-colonized mothers should be observed for at least 24 hours for signs of sepsis. Newborns who appear septic should have diagnostic work-up including blood culture followed by initiation of ampicillin and gentamicin. Studies indicate that intrapartum prophylaxis of GBS carriers and selective administration of antibiotics to newborns reduce neonatal GBS sepsis by as much as 80 to 95 percent.
Evaluation of Poststreptococcal Illness - Article
ABSTRACT: Group A beta-hemolytic streptococcal pharyngitis, scarlet fever, and rarely asymptomatic carrier states are associated with a number of poststreptococcal suppurative and nonsuppurative complications. As in streptococcal pharyngitis, acute rheumatic fever, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection, and poststreptococcal glomerulonephritis most often occur in children. The hallmarks of rheumatic fever include arthritis, carditis, cutaneous disease, chorea, and subsequent acquired valvular disease. Pediatric autoimmune neuropsychiatric disorders encompass a subgroup of illnesses involving the basal ganglia in children with obsessive-compulsive disorders, tic disorders, dystonia, chorea encephalitis, and dystonic choreoathetosis. Poststreptococcal glomerulonephritis is most frequently encountered in children between two and six years of age with a recent history of pharyngitis and a rash in the setting of poor personal hygiene during the winter months. The clinical examination of a patient with possible poststreptococcal complications should begin with an evaluation for signs of inflammation (i.e., complete blood count, erythrocyte sedimentation rate, C-reactive protein) and evidence of a preceding streptococcal infection. Antistreptolysin O titers should be obtained to confirm a recent invasive streptococcal infection. Other important antibody markers include antihyaluronidase, antideoxyribonuclease B, and antistreptokinase antibodies.
ABSTRACT: Erythema nodosum, a painful disorder of the subcutaneous fat, is the most common type of panniculitis. Generally, it is idiopathic, although the most common identifiable cause is streptococcal pharyngitis. Erythema nodosum may be the first sign of a systemic disease such as tuberculosis, bacterial or deep fungal infection, sarcoidosis, inflammatory bowel disease, or cancer. Certain drugs, including oral contraceptives and some antibiotics, also may be etiologic. The hallmark of erythema nodosum is tender, erythematous, subcutaneous nodules that typically are located symmetrically on the anterior surface of the lower extremities. Erythema nodosum does not ulcerate and usually resolves without atrophy or scarring. Most direct and indirect evidence supports the involvement of a type IV delayed hypersensitivity response to numerous antigens. A deep incisional or excisional biopsy specimen should be obtained for adequate visualization. Erythema nodosum represents an inflammatory process involving the septa between subcutaneous fat lobules, with an absence of vasculitis and the presence of radial granulomas. Diagnostic evaluation after comprehensive history and physical examination includes complete blood count with differential; erythrocyte sedimentation rate, C-reactive protein level, or both; testing for streptococcal infection (i.e., throat culture, rapid antigen test, antistreptoly-sin-O titer, and polymerase chain reaction assay); and biopsy. Patients should be stratified by risk for tuberculosis. Further evaluation (e.g., purified protein derivative test, chest radiography, stool cultures) varies based on the individual. Erythema nodosum tends to be self-limited. Any underlying disorders should be treated and supportive care provided. Pain can be managed with nonsteroidal anti-inflammatory drugs.
ABSTRACT: Neonatal group B streptococcal infection is the primary cause of neonatal morbidity related to infection. It can often be prevented by identifying and treating pregnant women who carry group B streptococci or who are at highest risk of transmitting the bacteria to newborns. Increasing evidence and expert opinion support intrapartum treatment of women at relatively high risk of delivering an infant with group B streptococcal infection. Such women can be identified through the use of an anogenital culture for group B streptococci obtained at 35 to 37 weeks of gestation and by the presence of at least one of many risk factors associated with neonatal infection. These risk factors include preterm labor or rupture of the membranes at less than 37 weeks of gestation, previous delivery of an infant with invasive group B streptococcal disease, group B streptococcal bacteriuria during the present pregnancy, maternal intrapartum fever of 38 degrees C (100.4 degrees F) or higher and rupture of the fetal membranes for 18 hours or more. The recommended agent for intrapartum chemoprophylaxis is intravenous penicillin G; clindamycin is used in penicillin-allergic women. The use of risk markers alone to guide the administration of intrapartum antibiotics is much more cost-effective than other preventive strategies, but it exposes more women and infants to antibiotic-associated risks. Management of the infants of treated mothers is empiric and is currently guided by expert opinion.
Perianal Streptococcal Dermatitis - Article
ABSTRACT: Perianal streptococcal dermatitis is a bright red, sharply demarcated rash that is caused by group A beta-hemolytic streptococci. Symptoms include perianal rash, itching and rectal pain; blood-streaked stools may also be seen in one third of patients. It primarily occurs in children between six months and 10 years of age and is often misdiagnosed and treated inappropriately. A rapid streptococcal test of suspicious areas can confirm the diagnosis. Routine skin culture is an alternative diagnostic aid. Treatment with amoxicillin or penicillin is effective. Follow-up is necessary, because recurrences are common.
Management of Bacterial Endocarditis - Article
ABSTRACT: Most cases of bacterial endocarditis involve infection with viridans streptococci, enterococci, coagulase-positive staphylococci or coagulase-negative staphylococci. The choice of antibiotic therapy for bacterial endocarditis is determined by the identity and antibiotic susceptibility of the infecting organism, the type of cardiac valve involved (native or prosthetic) and characteristics of the patient, such as drug allergies. Antibiotic therapies discussed in this report are based on recommendations of the American Heart Association. Treatment with aqueous penicillin or ceftriaxone is effective for most infections caused by streptococci. A combination of penicillin or ampicillin with gentamicin is appropriate for endocarditis caused by enterococci that are not highly resistant to penicillin. Vancomycin should be substituted for penicillin when high-level resistance is present. Resistance of enterococci to multiple antibiotics including vancomycin is becoming an increasing problem. Native valve infection by methicillin-susceptible staphylococci is treated with nafcillin, oxacillin or cefazolin. The addition of gentamicin for the first three to five days may accelerate clearing of bacteremia. Infection of a prosthetic valve by a staphylococcal organism should be treated with three antibiotics: oral rifampin and gentamicin and either nafcillin, oxacillin, cefazolin or vancomycin, depending on susceptibility to methicillin. Vancomycin is substituted for penicillin in patients with a history of immediate-type hypersensitivity to penicillin.
ABSTRACT: Bacteria are responsible for approximately 5 to 10 percent of pharyngitis cases, with group A beta-hemolytic streptococci being the most common bacterial etiology. A positive rapid antigen detection test may be considered definitive evidence for treatment; a negative test should be followed by a confirmatory throat culture when streptococcal pharyngitis is strongly suspected. Treatment goals include prevention of suppurative and nonsuppurative complications, abatement of clinical signs and symptoms, reduction of bacterial transmission and minimization of antimicrobial adverse effects. Antibiotic selection requires consideration of patients' allergies, bacteriologic and clinical efficacy, frequency of administration, duration of therapy, potential side effects, compliance and cost. Oral penicillin remains the drug of choice in most clinical situations, although the more expensive cephalosporins and, perhaps, amoxicillin-clavulanate potassium provide superior bacteriologic and clinical cure rates. Alternative treatments must be used in patients with penicillin allergy, compliance issues or penicillin treatment failure. Patients who do not respond to initial treatment should be given an antimicrobial that is not inactivated by penicillinase-producing organisms (e.g., amoxicillin-clavulanate potassium, a cephalosporin or a macrolide). Patient education may help to reduce recurrence.
Spontaneous Vaginal Delivery - Article
ABSTRACT: Vaginal delivery is a natural process that usually does not require significant medical intervention. Management guided by current knowledge of the relevant screening tests and normal labor process can greatly increase the probability of an uncomplicated delivery and postpartum course. All women should be screened for group B streptococcus; women who test positive should be treated with antibiotics during labor. Routine human immunodeficiency virus screening of all pregnant women, and treatment with antiretroviral medication for those who test positive, can reduce perinatal transmission of the infection. Once a woman is in labor, management should focus on the goal of delivering a healthy newborn while minimizing discomfort and complications for the mother. In a patient who tests negative for group B streptococcus, delaying admission to the labor ward until she is in active labor decreases the number of possible medical interventions during labor and delivery. Once a patient has been admitted to the hospital, providing her with continuous emotional support can improve delivery outcomes and the birthing experience. Epidural analgesia is effective for pain control and should not be discontinued late in labor to reduce the need for operative vaginal delivery. Epidurals prolong labor, but do not increase the risk of cesarean delivery. Research has shown that labor may not progress as rapidly as historically reported; this should be considered before intervening for dystocia. Routine episiotomy increases morbidity and should be abandoned. Once the infant has been delivered, active management of the third stage of labor decreases the risk of postpartum hemorrhage.
ABSTRACT: Common signs and symptoms of streptococcal pharyngitis include sore throat, temperature greater than 100.4 degrees F (38 degrees C), tonsillar exudates, and cervical adenopathy. Cough, coryza, and diarrhea are more common with viral pharyngitis. Available diagnostic tests include throat culture and rapid antigen detection testing. Throat culture is considered the diagnostic standard, although the sensitivity and specificity of rapid antigen detection testing have improved significantly. The modified Centor score can be used to help physicians decide which patients need no testing, throat culture/rapid antigen detection testing, or empiric antibiotic therapy. Penicillin (10 days of oral therapy or one injection of intramuscular benzathine penicillin) is the treatment of choice because of cost, narrow spectrum of activity, and effectiveness. Amoxicillin is equally effective and more palatable. Erythromycin and first-generation cephalosporins are options in patients with penicillin allergy. Increased group A beta-hemolytic streptococcus (GABHS) treatment failure with penicillin has been reported. Although current guidelines recommend first-generation cephalosporins for persons with penicillin allergy, some advocate the use of cephalosporins in all nonallergic patients because of better GABHS eradication and effectiveness against chronic GABHS carriage. Chronic GABHS colonization is common despite appropriate use of antibiotic therapy. Chronic carriers are at low risk of transmitting disease or developing invasive GABHS infections, and there is generally no need to treat carriers. Whether tonsillectomy or adenoidectomy decreases the incidence of GABHS pharyngitis is poorly understood. At this time, the benefits are too small to outweigh the associated costs and surgical risks.