Georges Peter

Prevention of bacterial endocarditis. Recommendations by the American Heart Association.

Objective To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease. Participants An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Society for Gastrointestinal Endoscopy. Evidence The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis, and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using the root words endocarditis, bacteremia, and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the US Preventive Services Task Force categories of evidence. Consensus Process The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment. Conclusions Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate-, and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered; and (6) for gastrointestinal or genitourinary procedures, the prophylactic regimens have been simplified. These changes were instituted to more clearly define when prophylaxis is or is not recommended, improve practitioner and patient compliance, reduce cost and potential gastrointestinal adverse effects, and approach more uniform worldwide recommendations.

Prevention of respiratory syncytial virus infections: Indications for the use of palivizumab and update on the use of RSV-IGIV

The Food and Drug Administration recently approved the use of palivizumab (palē-vizhū-mäb), an intramuscularly administered monoclonal antibody preparation. Recommendations for its use are based on a large, randomized study demonstrating a 55% reduction in the risk of hospitalization attributable to respiratory syncytial virus (RSV) infections in high-risk pediatric patients. Infants and children with chronic lung disease (CLD), formerly designated bronchopulmonary dysplasia, as well as prematurely born infants without CLD experienced a reduced number of hospitalizations while receiving palivizumab compared with a placebo. Both palivizumab and respiratory syncytial virus immune globulin intravenous (RSV-IGIV) are available for protecting high-risk children against serious complications from RSV infections. Palivizumab is preferred for most high-risk children because of ease of administration (intramuscular), lack of interference with measles–mumps–rubella vaccine and varicella vaccine, and lack of complications associated with intravenous administration of human immune globulin products. RSV-IGIV, however, provides additional protection against other respiratory viral illnesses and may be preferred for selected high-risk children including those receiving replacement intravenous immune globulin because of underlying immune deficiency or human immuno-deficiency virus infection. For premature infants about to be discharged from hospitals during the RSV season, physicians could consider administering RSV-IGIV for the first month of prophylaxis. Most of the guidelines from the American Academy of Pediatrics for the selection of infants and children to receive RSV-prophylaxis remain unchanged. Palivizumab has been shown to provide benefit for infants who were 32 to 35 weeks of gestation at birth. RSV-IGIV is contraindicated and palivizumab is not recommended for children with cyanotic congenital heart disease. The number of patients with adverse events judged to be related to palivizumab was similar to that of the placebo group (11% vs 10%, respectively); discontinuation of injections for adverse events related to palivizumab was rare.

Prevention of Bacterial Endocarditis: Recommendations by the American Heart Association

OBJECTIVE To update recommendations issued by the American Heart Association last published in 1990 for the prevention of bacterial endocarditis in individuals at risk for this disease. PARTICIPANTS An ad hoc writing group appointed by the American Heart Association for their expertise in endocarditis and treatment with liaison members representing the American Dental Association, the Infectious Diseases Society of America, the American Academy of Pediatrics, and the American Society for Gastrointestinal Endoscopy. EVIDENCE The recommendations in this article reflect analyses of relevant literature regarding procedure-related endocarditis, in vitro susceptibility data of pathogens causing endocarditis, results of prophylactic studies in animal models of endocarditis, and retrospective analyses of human endocarditis cases in terms of antibiotic prophylaxis usage patterns and apparent prophylaxis failures. MEDLINE database searches from 1936 through 1996 were done using the root words endocarditis, bacteremia, and antibiotic prophylaxis. Recommendations in this document fall into evidence level III of the US Preventive Services Task Force categories of evidence. CONSENSUS PROCESS The recommendations were formulated by the writing group after specific therapeutic regimens were discussed. The consensus statement was subsequently reviewed by outside experts not affiliated with the writing group and by the Science Advisory and Coordinating Committee of the American Heart Association. These guidelines are meant to aid practitioners but are not intended as the standard of care or as a substitute for clinical judgment. CONCLUSIONS Major changes in the updated recommendations include the following: (1) emphasis that most cases of endocarditis are not attributable to an invasive procedure; (2) cardiac conditions are stratified into high-, moderate-, and negligible-risk categories based on potential outcome if endocarditis develops; (3) procedures that may cause bacteremia and for which prophylaxis is recommended are more clearly specified; (4) an algorithm was developed to more clearly define when prophylaxis is recommended for patients with mitral valve prolapse; (5) for oral or dental procedures the initial amoxicillin dose is reduced to 2 g, a follow-up antibiotic dose is no longer recommended, erythromycin is no longer recommended for penicillin-allergic individuals, but clindamycin and other alternatives are offered; and (6) for gastrointestinal or genitourinary procedures, the prophylactic regimens have been simplified. These changes were instituted to more clearly define when prophylaxis is or is not recommended, improve practitioner and patient compliance, reduce cost and potential gastrointestinal adverse effects, and approach more uniform worldwide recommendations.

Standards for adult immunization practices

Since the Standards for Adult Immunization Practices were first published in 1990, healthcare researchers and providers have learned important lessons on how to better achieve and maintain high vaccination rates in adults. The success rate of childhood immunization far exceeds the success rate of adult immunization. Thus, information and practices that will produce higher success rates for adult vaccination are crucial, resulting in overall societal cost savings and substantial reductions in hospitalizations and deaths. The Standards, which were developed to encourage the best immunization practices, represent the collective efforts of more than 100 people from more than 60 organizations. The revised Standards are more comprehensive than the 1990 Standards and focus on the accessibility and availability of vaccines, proper assessment of patient vaccination status, opportunities for patient education, correct procedures for administering vaccines, implementation of strategies to improve vaccination rates, and partnerships with the community to reach target patient populations. The revised Standards are recommended for use by all healthcare professionals and all public and private sector organizations that provide immunizations for adults. All who are involved in adult immunization should strive to follow the Standards in order to create the same level of success achieved by childhood vaccination programs and to meet the Healthy People 2010 goals.

Circulating polyribophosphate in Hemophilus influenzae, type b meningitis. Correlation with clinical course and antibody response.

In systemic infections caused by Hemophilus influenzae, type b, the capsular polysaccharide, polyribophosphate, is released into the circulation. Polyribophosphate was quantitated in serial serum and cerebrospinal fluid samples from 45 children with H. influenzae, type b meningitis by means of a radiolabeled antigen-binding inhibition assay. Polyribophosphate was regularly found in acute serum and cerebrospinal fluid samples and could be detected in unbound form for periods of 1-30 days after initiation of effective therapy. Complexes of polyribophosphate dissociable with acid and pepsin were detected in serum samples from 17 patients, in one case for a period of 145 days after hospitalization. Polyribophosphate levels and patterns of clearance were studied in relation to hospital course and antibody response. Patients with prolonged antigenemia had protracted fevers and severe neurological symptoms during hospitalization, frequently with focal complications.Antipolyribophosphate antibody responses were detected during the first 100 days of convalescence by radioimmunoassay in 79% of the patients studied, including 60% of the children 1 yr or less in age. The intensity of antibody response although clearly related to the age of the patient, was more reliably predicted by the efficiency of antigen clearance. Antibody responses were uniformly of low magnitude in patients with prolonged antigenemia, irrespective of age. Paients who failed to develop antibody to polyribophosphate after meningitis also exhibited impaired antigen clearance. These studies suggest that mechanisms necessary for clearance of polyribophosphate may influence the development and intensity of the humoral immune response and raise the possibility of developmental deficiencies in the clearance system in infants and children.

Immunization of Humans with Polyribophosphate, the Capsular Antigen of Hemophilus influenzae, Type b

In human volunteers, single injections of purified polyribophosphate elicited antibodies detectable by passive hemagglutination and by serum bactericidal and opsonizing activities against viable Hemophilus influenzae, type b. All three activities rose by 2 wk to maximal levels, at which they remained for at least 6 months. Doses of 1 mug elicited antibody responses in nearly all recipients; higher doses of the antigen, however, produced larger increases in titer. Booster doses of 1 mug given at 6 months did not further increase the antibody titers. A tuberculin-like response was often observed at the site of injections given intradermally.

Prevention of Bacterial Endocarditis

Surgical and dental procedures and instrumentations involving mucosal surfaces or contaminated tissue commonly cause transient bacteremia that rarely persists for more than 15 minutes. Blood-borne bacteria may lodge on damaged or abnormal heart valves or on the endocardium or the endothelium near congenital anatomic defects, resulting in bacterial endocarditis or endarteritis. Although bacteremia is common following many invasive procedures, only a limited number of bacterial species commonly cause endocarditis. It is impossible to predict which patient will develop this infection or which particular procedure will be responsible. Certain cardiac conditions are more often associated with endocarditis than others (Table 1). Furthermore, certain dental and surgical procedures are much more likely to initiate the bacteremia that results in endocarditis than are other procedures (Table 2). Prophylactic antibiotics are recommended for patients at risk for developing endocarditis who are undergoing those procedures most likely to produce bacteremia with organisms that commonly cause endocarditis. Prophylaxis is most effective when given perioperatively in doses that are sufficient to assure adequate antibiotic concentrations in the serum during and after the procedure. To reduce the likelihood of microbial resistance, it is important that prophylactic

Clostridia colonization and clostridial toxin in neonatal necrotizing enterocolitis

produce clinical copper deficiency (except for a lower hematocrit at six months) in premature infants fed much lower copper intakes. This study suggests the age at which infants of different gestations can be expected to have an increase in serum copper and ceruloplasmin concentrations. Infants past that age (after 3 months in most very premature infants) who have very low serum copper concentrations may be copper deficient, especially if clinically compatible, and may benefit from additional copper supplies. Prior to that time, serum copper and ceruloplasmin values are probably inadequate indicators of total body copper status, and the benefit to risk ratio of copper supplementation is not established. In the great majority of infants, serum copper concentrations will rise spontaneously as either the liver, gastrointestinal tract, or both, mature.

A high degree of natural immunologic priming to the capsular polysaccharide may not prevent Haemophilus influenzae type b meningitis.

Background. A current debate is whether the immunologic priming of infants with Haemophilus influenzae type b (Hib) conjugate vaccines would be protective in the absence of circulating antibody to the capsular polysaccharide (PS). Data from the prevaccine era on the PS antibody responses of older children to Hib meningitis may be informative on this issue. Methods. PS antibody was assayed by radioantigen binding in sera taken in the first month postadmission in 47 children ages 2 to 136 months with culture‐proved Hib meningitis. Results. Sera obtained on admission had very low antibody concentrations, and the subsequent response during convalescence was age‐dependent. The major finding is that some patients, including 10 of 11 children older than 2 years, had substantial antibody elevations within a few days of admission, increases resembling the response to PS vaccine in infants primed with PS‐protein conjugate vaccines. Conclusions. In this group of patients with Hib meningitis, natural priming did not prevent infection. Hib may have the ability to invade despite the capacity for a vigorous antibody response.

Alterations in stool flora resulting from oral kanamycin prophylaxis of necrotizing enterocolitis.

To evaluate the effects of oral kanamycin prophylaxis for necrotizing enterocolitis on stool flora, 99 high-risk infants were studied on a double-blind basis during the first month of life. Oral kanamycin prophylaxis resulted in a significant decrase in gram-negative enteric colonization on Days 3 to 5, 10, 17, and 24 compared to control infants ( P P P =0.2). The data indicate that oral kanamycin prophylaxis significantly reduces the colonization rate and overgrowth of gram-negative enteric flora, but does not eliminate the occurrence of NEC in a high-risk group of infants.