Thomas L. Treadwell

Immunogenicity of two recombinant hepatitis B vaccines in older individuals

PURPOSE Currently available hepatitis B vaccines are recombinant, yeast-derived preparations given in 10-micrograms or 20-micrograms doses. The optimum dose remains controversial. We sought to assess the relative immunogenicity of two hepatitis B vaccines, given in different doses, in older individuals. PATIENTS AND METHODS In a multicenter, double-blind, randomized clinical trial, a total of 460 healthy subjects between 39 and 70 years of age were screened and immunized with either Engerix-B 20 micrograms or Recombivax HB 10 micrograms in standard, intramuscular, 3-dose regimens. Of these, 397 subjects were eligible to continue vaccination. Immunogenicity was measured by determination of antibody to hepatitis B surface antigen (anti-HBs). Seroconversion and seroprotection rates, and geometric mean titers of anti-HBs were calculated at 1, 3, 6, and 8 months after the initial dose of vaccine. RESULTS Seroprotection rates for subjects receiving the 20-micrograms dose of vaccine were slightly, but not significantly, greater than for subjects receiving the 10-micrograms dose, at each time point. However, at 3 months, males receiving the higher dose had significantly higher seroprotection rates than males receiving the lower dose: 63% versus 37% (p < 0.001). At 8 months, geometric mean titers for the group receiving Engerix-B 20 micrograms were significantly greater than that for the group receiving Recombivax HB 10 micrograms: 840 mIU/mL versus 340 mIU/mL (p = 0.001). CONCLUSIONS Immunization with the 20-micrograms dose of recombinant hepatitis B virus vaccine appeared to result in more rapid development of seroprotective anti-HBs titers in older men and in higher titers of anti-HBs at the completion of vaccination when compared to the 10-micrograms dose. The latter data suggest that the 20-micrograms dose may result in a longer duration of seroprotective anti-HBs titers.

Surveillance for transmission and antibiotic adverse events among neonates and adults exposed to a healthcare worker with pertussis.

BACKGROUND During a hospital obstetric rotation, a medical student demonstrated classic symptoms of pertussis. The diagnosis was confirmed by isolation of Bordetella pertussis. Because this exposure occurred in a high-risk hospital setting, control measures were undertaken to prevent transmission and illness. OBJECTIVES To identify secondary cases of pertussis, to determine compliance with chemoprophylaxis recommendations, and to monitor for adverse events associated with chemoprophylaxis following a hospital exposure to pertussis. PATIENTS More than 500 individuals were potentially exposed, including 168 neonates; antimicrobial chemoprophylaxis was administered to 281 individuals. Fifty-eight neonates and 194 adults began azithromycin chemoprophylaxis; 18 neonates and 2 adults began erythromycin chemoprophylaxis. METHODS Active surveillance was instituted for (1) secondary cases of pertussis among healthcare coworkers, obstetric patients, their neonates, and labor companions and (2) antibiotic compliance and tolerance. RESULTS No secondary cases of pertussis were confirmed by laboratory tests; however, 26 suspected cases and 5 clinically compatible cases were identified. Antibiotic courses were completed by 95% of the individuals who initiated therapy. Neonates taking azithromycin had statistically significantly less gastrointestinal distress compared with neonates taking erythromycin (12% vs 50%; P = .002); there were no cases of infantile hypertrophic pyloric stenosis. CONCLUSIONS Although it was not possible to assess the effectiveness of the antibiotic regimens, the lack of laboratory-confirmed secondary cases suggests control measures were successful. Data from the 58 neonates who received azithromycin suggest it may be well tolerated in this age group.

Randomized clinical trial of aztreonam and aminoglycoside antibiotics in the treatment of serious infections caused by gram-negative bacilli.

Aztreonam was compared with aminoglycoside antibiotics (tobramycin and amikacin) in a randomized, prospective, clinical trial in serious infections caused by gram-negative bacilli (GNB). A total of 43 evaluable patients with 47 infected sites were treated with aztreonam, and 41 evaluable patients were treated with aminoglycosides for 43 infections. Of patients treated with aztreonam, 17 were bacteremic, as were 12 of those treated with aminoglycosides. Clinical and microbiologic response rates were similar, except that only 5 of 11 patients with pneumonia were considered to be clinically cured with aminoglycoside therapy, while 5 of 6 patients with pneumonia treated with aztreonam were cured. Renal impairment was observed in 9 of 54 patients who received aminoglycoside antibiotics, but in only 2 of 53 patients treated with aztreonam. Hearing impairment developed in one patient treated with tobramycin. Transient elevations of serum transaminase levels occurred in 9 of 53 patients treated with aztreonam and in only 2 of 54 aminoglycoside-treated patients. Diarrhea and superinfection occurred with equal frequency in both groups. Serum concentrations of bactericidal activity could not be correlated with the outcome of therapy. Aztreonam appears to have comparable clinical efficacy with aminoglycoside antibiotics for the treatment of serious infections caused by aerobic and facultative GNB. Its use as a single agent for the treatment of serious lower respiratory infections caused by GNB warrants further evaluation.

Xanthogranulomatous pyelonephritis caused by methicillin-resistant Staphylococcus aureus

Localized xanthogranulomatous pyelonephritis due to methicillin-resistant Staphylococcus aureus developed in a 41-year-old diabetic patient. She had recurrent bacteremia despite appropriate therapy with vancomycin. Nephrectomy was required for cure and clinical diagnosis. This report emphasizes differences in the clinical presentation and pathogenesis of xanthogranulomatous pyelonephritis caused by S. aureus. Compared with the common form of xanthogranulomatous pyelonephritis caused by gram-negative bacilli, the localized disease due to S. aureus probably results from hematogenous seeding and is not associated with nephrolithiasis or ureteral obstruction. Furthermore, this report indicates that xanthogranulomatous pyelonephritis may be caused by methicillin-resistant S. aureus, a rapidly emerging nosocomial pathogen.

Treatment of pancreatitis: When do antibiotics have a role?

Experimental and clinical data on the use of antibiotics in treatment of pancreatitis vary widely, depending on the cause of the disease. Antibiotics have little effect on alcoholic or idiopathic pancreatitis, but they play a major role in treatment of bacterial infections in gallstone pancreatitis. Some antibiotics are effective in necrotizing pancreatitis; however, surgery and extensive debridement are often necessary when abscess is present or multiple-organ failure occurs.

Sphingomonas paucimobilis empyema caused by remote foreign body aspiration

Empyema secondary to foreign body aspiration is rare in adults. We present a case of empyema in a 77-year-old male patient related to a remote aspiration event during a dental procedure. A CT of the chest and bronchoscopy confirmed that a metallic foreign body was located within the right lower lobe bronchus. His pleural fluid culture revealed Sphingomonas paucimobilis which is a low-virulent opportunistic gram-negative bacilli and rarely causes infection. The patient received meropenem followed by levofloxacin and recovered uneventfully. The attempt of foreign body removal was failed due to chronic inflammation, and the patient refused further surgical management.