Ram Yogev

Intravenous Immune Globulin for the Prevention of Bacterial Infections in Children with Symptomatic Human Immunodeficiency Virus Infection

BACKGROUNDnSerious recurrent bacterial infections are a major cause of morbidity and mortality in children infected with the human immunodeficiency virus (HIV). Because intravenous immune globulin has been shown to prevent bacterial infection in patients with primary immunodeficiency and in uncontrolled studies of HIV-infected children, we undertook a multicenter study of its safety and efficacy in children with symptomatic HIV infection.nnnMETHODSnIn a double-blind trial, 372 HIV-infected children (mean age, 40 months) with clinical or immunologic evidence of HIV disease were randomly assigned to receive either intravenous immune globulin (400 mg per kilogram of body weight) or placebo (0.1 percent albumin) every 28 days. The children were stratified into two groups according to CD4+ lymphocyte count at entry into the study and the clinical classification of the Centers for Disease Control. The median length of follow-up was 17 months.nnnRESULTSnFor children in either group with CD4+ counts greater than or equal to 0.2 x 10(9) per liter (greater than or equal to 200 per cubic millimeter) at entry, treatment with intravenous immune globulin significantly increased the time free from serious infection; estimated infection-free rates after 24 months were 67 percent for children receiving immune globulin as compared with 48 percent for those receiving placebo (P = 0.01). In addition, immune globulin was associated with an overall reduction in the number of both serious and minor bacterial infections (relative risk, 0.68; P = 0.01) and in the number of hospitalizations for acute care (relative risk, 0.65; P = 0.03). No such benefits were seen for children with CD4+ counts below 0.2 x 10(9) per liter at entry. For group 1 overall, there was a trend toward a difference in serious bacterial infection between immune globulin and placebo (24-month infection-free survival, 31 percent for intravenous immune globulin vs. 25 percent for placebo; P = 0.10). For group 2, the estimates of survival without serious infection were 73 percent with intravenous immune globulin as compared with 53 percent with placebo (P = 0.04). There was no effect of treatment on mortality for any group or CD4+ count at entry. Adverse reactions, noted for less than 1 percent of infusions, were minor.nnnCONCLUSIONSnIn symptomatic HIV-infected children the prophylactic use of intravenous immune globulin, is safe, and it significantly increases the time free from serious bacterial infections for those entering treatment with CD4+ lymphocyte counts greater than or equal to 0.2 x 10(9) per liter.

Sputum changes associated with therapy for endobronchial exacerbation in cystic fibrosis

We sought to define objective indicators of the resolution of Pseudomonas aeruginosa endobronchial infection in patients with cystic fibrosis. We prospectively studied 75 patients admitted for treatment of a pulmonary exacerbation and quantitated sputum bacterial density, DNA content, and the concentration of albumin and total protein in sputum, and compared these values with clinical evaluation. Eleven of the 75 patients had systemic signs, fever, and leukocytosis, which we arbitrarily defined as due to endobronchial infection. At the end of hospitalization, these 11 patients were afebrile, had peripheral leukocyte counts in the normal range, and were judged improved. Sputum P. aeruginosa density, DNA content, and total protein content on admission were similar in the two illness groups. Hospitalization and parenteral antibiotic administration for an average of 14.6 days were associated with improved pulmonary function in all 75 subjects (P values for forced vital capacity, forced expiratory volume at 1 second, and peak expiratory flow rate were all less than 0.001). With improvement, there was a decrease in sputum P. aeruginosa density (mean of both groups decreased from 10(7.80) CFU/g on admission to 10(5.96) CFU/g; P less than 0.001), and a decreased DNA concentration (overall mean 4.73 +/- 4.75 on admission to 2.76 +/- 2.49 mg/g; P less than 0.002). The decrease in sputum total protein concentration for both groups was not significant (overall mean 60.5 +/- 48.4 to 43.9 +/- 38.2 mg/g; P = 0.06). Sputum albumin concentrations did not change in either group. We conclude that in cystic fibrosis subjects with a pulmonary exacerbation, bacterial density, sputum DNA and protein content decrease with hospitalization and parenteral antibiotic therapy. At the end of treatment, these indices of sputum infection and inflammation correlate with improved pulmonary function and clinical improvement. These changes are independent of the presence or absence of fever on admission.

Varicella-zoster virus infections in children infected with human immunodeficiency virus.

Primary varicella-zoster (VZ) infection in eight children with perinatally acquired human immunodeficiency virus infection tended to be severe, prolonged, complicated by bacterial infections and in one case fatal. Depletion of CD4-lymphocytes was associated with chronic and recurrent VZ infection. In some patients convalescent VZ antibody titers were low and did not correlate with recurrence of VZ lesions. Administration of acyclovir appeared to be beneficial in suppressing VZ in human immunodeficiency virus-infected children with primary or recurrent VZ infection.

Invasive pneumococcal infections in children with asplenia.

Background. Asplenia is associated with an increased risk of infections caused by Streptococcus pneumoniae. Overwhelming infection can be fulminate and lead to a fatal outcome. Objective. To review the epidemiology and clinical course of invasive S. pneumoniae infections in children with asplenia before the release of the conjugate pneumococcal vaccine. Methods. Children with S. pneumoniae infections from eight children’s hospitals in the US were identified prospectively from September, 1993, to August, 1999. Further demographic, medical and microbiologic information was gathered retrospectively from the charts of patients with asplenia. Results. Twenty-two asplenic patients with 26 episodes of invasive S. pneumoniae were identified. This represents 1% of the 2581 episodes of invasive S. pneumoniae infections identified in our study. Twelve had congenital asplenia (CA), and 10 had undergone surgical splenectomy. Nine of the patients with CA had associated complex congenital heart disease. The median age at first infection was 12.5 months for CA patients as compared with 69 months in children with surgical splenectomy (P < 0.001). Seventy-five percent of those eligible had received the polysaccharide pneumococcal vaccine. The most common serotypes isolated were 6B (8), 23F (7), 18C (2) and 19A (2). Antimicrobial prophylaxis had been prescribed for 82% of the study cohort. Clinical presentations of the 26 episodes included fever (22), shock (7), petechiae or purpura (7), disseminated intravascular coagulation (5) and respiratory distress (5). Clinical illness included bacteremia alone (12), meningitis alone (8), bacteremia with otitis media-sinusitis (3), bacteremia with pneumonia (2) and meningitis with osteomyelitis (1). Five of the 6 patients who died had meningitis. Three of the survivors (19%) had significant morbidity, and all of them had meningitis. Two patients had 2 episodes each, and 1 patient had 3 episodes. All but 1 of the multiple episodes was with a different serotype. Forty-six percent of isolates were nonsusceptible to penicillin, and 19% were nonsusceptible to ceftriaxone. There was no association between antimicrobial resistance and mortality. Conclusions. Invasive pneumococcal disease in patients with asplenia has a high mortality, especially in those with meningitis. Even though the new conjugate vaccine might increase protection, 19% of patients had disease caused by serotypes not included in the current heptavalent vaccine. Clinicians should continue to be aggressive in evaluating asplenic patients with unexplained fevers.

Clindamycin treatment of chronic pharyngeal carriage of group A streptococci

We previously demonstrated that chronic pharyngeal carriage of group A beta-hemolytic streptococci (GABHS) can be terminated by intramuscular administration of benzathine penicillin plus 4 days of orally administered rifampin. Because an effective oral regimen would be desirable, we compared clindamycin with P + R for treating GABHS carriage. Healthy, symptom-free GABHS carriers were randomly assigned to receive orally administered clindamycin (20 mg/kg per day) three times a day for 10 days or intramuscularly administered benzathine penicillin with oral doses of rifampin (20 mg/kg per day) twice a day for 4 days. Compliance was documented by antibiotic activity in urine. Throat cultures for GABHS were obtained every 3 weeks for up to 9 weeks after treatment. Patients who had positive throat cultures for their original GABHS T type 3 weeks after randomization were crossed over to the other treatment. Treatment success was defined as eradication of the original GABHS T type, with all follow-up cultures negative. Clindamycin eradicated carriage in 24 (92%) of 26 patients; penicillin plus rifampin was effective in 12 (55%) of 22 patients (p less than 0.025). Including patients crossed over 3 weeks after enrollment, clindamycin was effective in 28 (85%) of 33 treatment courses compared with 12 of 22 courses of penicillin plus rifampin (p less than 0.05). We conclude that 10 days of oral clindamycin therapy was significantly more effective than benzathine penicillin plus 4 days of orally administered rifampin for treatment of symptom-free GABHS carriers.

Ventriculoperitoneal Shunt Infections with Gram-Negative Bacteria

Infection causes major morbidity and mortality in patients with cerebrospinal fluid (CSF) shunts. The prognosis of CSF shunt infections caused by Gram-negative bacteria (GNB) has been thought to be particularly poor. The authors reviewed all GNB shunt infections treated at Childrens Memorial Hospital from January 1986 to January 1990 (n = 23). Of these infections 20 (87%) occurred within 4 weeks after shunt revision (median, 10 days). The most frequent symptoms were fever, lethargy, and irritability; the illness was not severe in the majority of these patients. Escherichia coli was isolated from 12 of 23 patients (52%), Klebsiella pneumoniae from 5 (22%), and mixed GNB from 3 (13%) patients. Initial treatment always included immediate shunt removal, externalized ventricular drainage, and intravenous antibiotics. Extraventricular drainage revision and/or intraventricular antibiotics were required in four patients whose CSF cultures were persistently positive for GNB. At admission, these patients had CSF glucose levels of < 10 mg/dl and CSF positive for GNB by Grams stain. The overall cure rate was 100%, and no recurrence was observed; however, a subsequent infection with a different organism developed in four patients. Only 2 of 19 patients (11%) who were followed up suffered apparent CNS damage. One patient died of unrelated causes shortly after treatment. Our findings indicate that 1) patients with GNB CSF shunt infections often appear relatively well at presentation; 2) CSF positive for GNB by Grams stain and very low CSF glucose levels predict continued positive CSF cultures, despite appropriate antibiotic therapy; and 3) GNB CSF shunt infections can be successfully treated by prompt shunt removal, extraventricular drainage, and intravenous antibiotics.(ABSTRACT TRUNCATED AT 250 WORDS)

The localization of urinary tract infection with99mTc glucoheptonate scintigraphy

A retrospective study was performed of 39 children at the Childrens Memorial Hospital, Chicago, Illinois, who underwent technetium-99m glucoheptonate (99mTcGH) scintigraphy for evaluation of possible urinary tract infection. Clinical and laboratory criteria classified the children as having pyelonephritis, cystitis, or no urinary tract infection. Of 28 children classified as having pyelonephritis, 24 (86%) children had abnormalities on99mTcGH scintigraphy. Only 8 of 19 (42%) renal ultrasound scans and 4 of 17 (24%) intravenous pyelography studies performed in these children demonstrated findings consistent with parenchymal disease. Only 9 of 19 (47%) cystograms demonstrated vesicoureteral reflux. Three children who underwent gallium-67 citrate scintigraphy had localization at the sites of focal defects with99mTcGH scintigraphy.99mTcGH scintigraphy is a sensitive and specific indicator of renal parenchymal involvement that helps localize urinary tract infection to the kidney.

Lack of influence of beta-lactamase-producing flora on recovery of group A streptococci after treatment of acute pharyngitis

Because production of beta-lactamase by normal pharyngeal flora could account for penicillin treatment failure, we studied the effect of anaerobic and aerobic beta-lactamase-producing bacteria on bacteriologic outcome in acute group A beta-hemolytic streptococcal (GABHS) pharyngitis. We compared 10-day courses of orally administered phenoxymethyl penicillin and amoxicillin-clavulanic acid, using a randomized, single-blind treatment protocol. Eligible patients were 2 to 16 years of age and had culture-proven acute GABHS pharyngitis; 89 patients (43 penicillin, 46 amoxicillin-clavulanic acid) were compliant with therapy. beta-Lactamase-producing organisms were isolated before therapy from the throats of 67% of patients treated with penicillin and 63% treated with amoxicillin-clavulanic acid. Throat cultures after completion of therapy were positive for GABHS in 7 (7.9%) of 89 patients. The initial GABHS T type persisted (treatment failure) in only 4 (4.5%) of 89 patients, including 3 (6.5%) of 46 who received amoxicillin-clavulanic acid and in 1 (2.3%) of 43 who received penicillin (not statistically significant). Bacteriologic treatment failure was unrelated to recovery of beta-lactamase-producing bacteria at the time of enrollment or after treatment. We conclude that beta-lactamase production by normal pharyngeal flora does not fully explain the failure of penicillin therapy for acute streptococcal pharyngitis. Using an antibiotic effective against beta-lactamase-producing bacteria will not eliminate the problem of bacteriologic treatment failure.

Molecular cloning of a gene involved in lipooligosaccharide biosynthesis and virulence expression by Haemophilus influenzae type B

A wild‐type Haemophilus influenzae type b (Hib) genomic DNA library was constructed in the plasmid shuttle vector pGJB103. A virulence‐deficient lipooligosaccharide (LOS) mutant of Hib was used as a recipient for genetic transformation to screen this Hib genomic DNA library for genes involved in LOS expression. A recombinant plasmid containing a 7.8 kb Pstl fragment of Hib DNA was shown to transform this LOS mutant to reactivity with a monoclonal antibody (mAb) specific for a wild‐type LOS epitope. Transformation of two different virulence‐deficient LOS mutants with a 4.4kb BglII fragment of this recombinant plasmid yielded transformants which expressed LOS that bound the wild‐type LOS‐specific mAb and yielded profiles in sodium dodecyl sulphate/polyacrylamide gradient gel electrophoresis different from those of the original LOS mutants. These transformants with structurally altered LOS molecules also exhibited increased virulence in an animal model for invasive Hib disease. The virulence‐transforming ability was further localized to a 1.8kb BglII‐AlwNI fragment of the Hib DNA insert. Nucleotide sequence analysis indicated the presence of a single large open reading frame within this fragment. This open reading frame contained 19 consecutive repeats of the tetramer CAAT near the 5’end. Linker insertion mutagenesis was used to demonstrate directly the involvement of this open reading frame in both LOS biosynthesis and virulence expression by Hib.

Serum tumor necrosis factor alpha, interleukin 1-beta, p24 antigen concentrations and CD4+ cells at various stages of human immunodeficiency virus 1 infection in children.

We measured the serum concentrations of tumor necrosis factor (TNF-alpha), interleukin 1-beta (IL-1-beta), p24 antigen, CD4+/CD8+ cells and immunoglobulins in 35 children at various stages of human immunodeficiency virus infection. Serum TNF-alpha concentrations were significantly higher in children with lymphocytic interstitial pneumonitis and in children with mildly symptomatic illness than in asymptomatic children or children with acquired immunodeficiency syndrome. In addition serum IL-1 concentrations were significantly higher in patients with lymphocytic interstitial pneumonitis than in asymptomatic, mildly symptomatic, or acquired immunodeficiency syndrome patients. Children with lymphocytic interstitial pneumonitis had the highest serum TNF-alpha and IL-1 concentrations. Among symptomatic children serum TNF-alpha concentrations correlated positively with those of IL-1, and both were inversely related to the amount of p24 antigen. TNF-alpha values in excess of 50 pg/ml were observed more frequently among patients with CD4+ cell count greater than 400/mm3 than in those with CD4+ cell count less than 400/mm3. We did not find any association between elevated TNF-alpha concentrations and cachexia, opportunistic infections or progressive encephalopathy.