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Biomedical subjects

C J Baker

Publications and source records attributed to C J Baker.

At least 271 records · Page 15Linked to original sources
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Bacillus species infections in neonates.

A case of neonatal meningitis due to Bacillus cereus is presented. Postmortem histopathologic examination revealed an invasive disease involving the brain parenchyma, with a cellular composition consistent with an indolent process indicative of possible perinatally acquired infection. One other neonate from our institution with systemic disease due to a nonanthrax bacillus is described, and a review of the English-language literature since 1900 reveals four additional neonates infected with these unusual pathogens. Such Bacillus species infections are rare but should be suspected when gram-positive bacilli are noted on gram stain, especially in an immunocompromised host.

Bacillus↗
PubMedDate not supplied

Role of intravenous immunoglobulin in prevention of late-onset infection in low-birth-weight neonates. The Neonatal IVIG Study Group.

As a result of inadequate placental transport of maternal IgG, preterm neonates of less than 32 weeks' gestation, especially those with birth weights less than 1,500 g, are profoundly hypogammaglobulinemic at birth, a condition that worsens during the first several weeks of life. This hypogammaglobulinemia is believed to contribute to their high frequency of late-onset sepsis, with its accompanying morbidity and mortality. Animal studies suggest that human immunoglobulin prepared for intravenous use (IVIG) improves host defense against pathogens that cause neonatal infections, but studies of IVIG in human neonates have been inconclusive because of the small numbers of infants included, lack of suitable controls, use of clinical rather than strict microbiologic definition of sepsis, and performance only in a single hospital outside the United States. A double-blind, randomized, placebo-controlled multicenter trial in the United States is in progress to determine the efficacy of IVIG in the prevention of late-onset infections in infants with birth weights between 500 and 1,750 g. Infants are infused with 500 mg of IVIG/kg or albumin-saline placebo at 3-7 days of age, 7 days later, and every 14 days for five doses. Efficacy parameters include mortality, number of proved infectious episodes (bacterial, fungal, or viral), and infection-related morbidity. Definitive guidelines for the possible use of prophylactic IVIG in low-birth-weight neonates should result from this evaluation of 500 to 700 infants in the United States.

Agammaglobulinemia↗
PubMedDate not supplied

Potential use of intravenous immune globulin for group B streptococcal infection.

Several lines of evidence suggest that passive immunization as adjunctive therapy for or prevention of group B streptococcal (GBS) sepsis in neonates will require the use of preparations of human intravenous immune globulin (IVIG) that are hyperimmune for protective antibodies to GBS. Results from both in vitro and in vivo experiments utilizing commercially available IVIG preparations suggest that the doses necessary for achieving levels of pathogen-specific antibody capable of promoting efficient opsonization and phagocytosis of GBS may be prohibitive. Several laboratories have reported that standard IVIG preparations contain only modest levels of antibodies to the four capsular polysaccharides of GBS (the protective moieties), are variable in their effect on in vitro opsonophagocytosis by dose and method of preparation, and are significantly less protective in animal models than is IVIG prepared from adults immunized with GBS polysaccharide vaccines. Further, when we gave a single infusion of standard IVIG at a dose of either 500 or 750 mg/kg to 10 premature neonates during the first week of life, opsonophagocytosis of type III GBS by their sera and adult neutrophils was observed only when high levels of specific antibody were achieved, levels only transiently achieved in nonimmune infants. Commercial preparation of human immune globulin hyperimmune for GBS will be required for optimal adjunctive therapy in patients with sepsis due to GBS and for the possible prevention of late-onset infant disease.

Antibodies, Bacterial↗
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Nontypable Haemophilus influenzae (biotype 4) as a neonatal, maternal, and genital pathogen.

Between 1976 and 1981 Haemophilus influenzae was identified in 16 women with postpartum bacteremia and 36 neonates with bacteremia or meningitis. H. influenzae was also recovered from neonatal or genital cultures of 50 additional patients. By counter-immunoelectrophoresis 17% of neonatal isolates from blood or cerebrospinal fluid (CSF) were type b. All remaining strains (94% overall) were nontypable (NT). Of the NT blood or CSF isolates, 38% belonged to biotype 4. Of all the NT biotype 4 isolates referred to the Centers for Disease Control during the study, 82% were of genital, neonatal, or maternal origin, a finding that suggests that this isolate is a genital biotype. Clinical disease was similar to that observed in patients infected with group B Streptococcus except for the infrequent (11%) occurrence of meningitis. Maternal bacteremia resulted in mild febrile illness, while neonatal bacteremia was associated with a high incidence of shock, respiratory distress (50%), and death (30%). H. influenzae bacteremia in these two patient groups was rare in Houston before 1976, but since then it has been responsible for 2.5% of cases of significant bacteremia. NT H. influenzae should be recognized as a definite neonatal, maternal, and genital pathogen.

Female↗
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Group B streptococcal vaccines.

In recent years group B Streptococcus (GBS) has been recognized as a major perinatal pathogen. As with other encapsulated bacteria, protective immunity appears to correlate with serum antibody specific for the homologous capsular polysaccharide antigen of each serotype. Since susceptibility of the young infant to disseminated GBS infection relates to type-specific antibody deficiency in maternal serum, immunization of women with purified GBS type-specific polysaccharides has been proposed as a method for the prevention of infant disease through placental transport of protective antibodies. Candidate native polysaccharides from GBS have been purified, immunochemically and structurally characterized, and employed as immunogen in healthy adult volunteers. Native type Ia, II, and III polysaccharides have been shown to be nontoxic, safe, and immunogenic in approximately 65%, 95%, and 70%, respectively, of nonimmune adults. Antibody response to immunization approaches 100% in previously immune volunteers. Vaccine-induced type-specific antibodies to these candidate polysaccharide vaccines promote in vitro opsonophagocytosis, protect animals given a lethal challenge of homologous organisms, and are predominantly of the IgG isotype. Once similar results can be documented in women immunized during the last half of pregnancy, efficacy of these candidate GBS polysaccharide vaccines in the prevention of neonatal and young infant GBS disease should be evaluated.

Adult↗
PubMedDate not supplied

Relapse of Escherichia coli meningitis following therapy with moxalactam.

Bacteriologic relapse occurred in a premature infant with Escherichia coli K1 meningitis 11 days following the completion of a 3-week course of therapy with the new 1-oxa-beta-lactam antibiotic moxalactam. Therapeutic failure was most probably the result of sequestration of viable bacteria in ventricular and/or paraventricular sites. While in vitro data and preliminary clinical evaluation of the new beta-lactam antibiotics indicate that these agents may be useful in the treatment of neonatal Gram-negative enteric meningitis, undue optimism regarding their efficacy, as with former agents, may be unwarranted.

Cephalosporins↗
PubMedDate not supplied

Median sternotomy wound infections in children.

Nine children (25 days to 15 years of age) with infectious complications of median sternotomy are described. Six infections were superficial and in three the sternum and/or mediastinum was involved. Risk factors predisposing to sternal wound infections in six patients were a pump bypass time in excess of 1 hour, excessive postoperative bleeding, low cardiac output for 24 hours or more postoperatively, reexploration for control of bleeding and inadequate antimicrobial prophylaxis. Eight infections were diagnosed at a mean of 15 days postoperatively (range, 5 to 30 days), and chronic sternal osteomyelitis was diagnosed 4 years after operation in one patient. Stability of the sternum was a critical feature differentiating between superficial and deep wound infections. Staphylococcus aureus or Staphylococcus epidermidis was isolated from the wound and/or blood of five patients, and Gram-negative enteric rods were isolated in three patients (two with sternal osteomyelitis and mediastinitis). Local debridement was sufficient for adequate drainage in four patients, but reexploration for debridement and rewiring of the sternum or drainage of mediastinal contents was required in four. All patients improved initially following drainage and administration of parenteral antibiotics for a mean of 12 (superficial infection) or 28 (deep infection) days. Two patients developed chronic sternal osteomyelitis, and one died due to rupture of a mycotic aneurysm of the aorta 7 years postoperatively.

Adolescent↗