Reviews of infectious diseases最新文献

Vaccinia virus recombinants containing the herpes simplex virus (HSV) gene for glycoprotein D type 1 (gD-1) under control of an early (VP176) or late (VP254) vaccinia virus promoter or for HSV glycoprotein type 2 (gD-2) under control of the early promoter (VP221) were studied for their ability to induce protective immunity to HSV-2 in the guinea pig model of cutaneous recurrent disease and the mouse model of fatal disease. Titers of HSV-specific neutralizing antibody were similar in the two groups of immunized animals, but HSV-specific T cell responses were significantly higher in VP176-immunized than in VP254-immunized animals, as determined by lymphoproliferation (P less than .005) and delayed-type hypersensitivity (P less than .01) responses. The reduced responses correlated with poor expression of the gD protein and its impaired processing in infected antigen-presenting cells (splenic adherent and epidermal cells). VP176 immunization protected against primary (P much less than .001) and recurrent (P much less than .001) cutaneous HSV-2 lesions and ganglionic latency (62% protection) in the guinea pig and against zosteriform skin lesions and fatal disease in the mouse. Immunization with VP254 was not protective. In guinea pigs VP221 did not protect against primary HSV-2 cutaneous disease but did reduce the proportion of animals with recurrent disease (P less than .05). This partial protection appears to be associated with the role of type-specific antigenic determinants in gD-2 immunoregulation.

The CSF of 57 infants and children with bacterial or enterovirus meningitis was analyzed for the presence of interferon (IFN). CSF was collected when the diagnosis of meningitis was made; a bacterium or enterovirus was isolated in all cases. IFN was detectable in CSF in 24% of cases of bacterial meningitis and in 75% of cases of viral meningitis. Titers of IFN were generally lower in cases of bacterial meningitis. Neither the presence of IFN nor the level of IFN titers correlated with the patient's age or number of white blood cells or mononuclear cells in the CSF. Coxsackievirus induced production of IFN more consistently and in higher titers than did echovirus. None of 35 control patients had detectable IFN in CSF. A literature review and our data indicate that the presence of IFN in CSF suggests infection of the CNS but does not differentiate bacterial from viral infection. The finding of IFN in the CSF of children with bacterial meningitis supports evidence that bacteria and other nonviral microorganisms induce IFN production. The protective role of IFN in nonviral infections deserves further investigation.

A 39-year-old man developed paroxysmal cough, occasional vomiting after cough, and subconjunctival hemorrhage. His illness was complicated by episodes of seizure, with clonic movements of the arms and legs, brief loss of consciousness, and confusion. The episodes were triggered by mild, unremarkable coughing paroxysms. A diagnosis of pertussis was confirmed serologically by measurement of IgG, IgA, and IgM antibodies to pertussis toxin and filamentous hemagglutinin. Serologic studies confirmed the presence of Bordetella pertussis infection in the patient's 10-year-old daughter and suggested that his wife was infected as well. This case report illustrates the occurrence of typical pertussis with serious complications in an adult. Further research is required to determine the scope of this problem and the need for a program of adult immunization against pertussis.

Two recombinant herpes simplex viruses, of type 1 background, were constructed with two large deletions and duplicate sets (type 1 and type 2) of the genes coding for glycoproteins D, G, and E. One recombinant (R7020) is thymidine kinase-positive, and the other (R7017) is thymidine kinase-negative. Evaluation in rodents indicated that these viruses are genetically stable, capable of establishing latency, protective against severe herpetic diseases, and protective against the establishment of latency. In Aotus monkeys, R7020 replicates at the site of inoculation but does not disseminate in the body. It can reactivate from the latent state but without causing recurrent lesions, even in immunosuppressed monkeys.

Many issues affect the design, conduct, and analysis of clinical evaluations of perioperative antibiotic prophylaxis. The most important of these are the selection of appropriate procedures for evaluation, the choice of meaningful outcomes, the comparison of outcomes among groups of patients who are really comparable to one another, the unbiased assessment of outcomes, the assessment of a number of patients sufficient to provide adequate statistical power for the detection of meaningful differences, and the generalizing of results. In evaluating perioperative prophylaxis, investigators often strive to identify small absolute differences among the risks of infections with different prophylactic regimens. For many specific procedures and drug regimens, such evaluations are limited by the difficulty of studying a sufficient number of individuals. Although randomized clinical trials are the standard for clinical evaluation, observational data may also prove useful under some circumstances.

Current opinion favors the use of antimicrobial prophylaxis in all operations for acute appendicitis. In clinical trials with placebo controls, the reduction in the rate of postoperative infectious complications is most apparent in perforated and/or gangrenous appendicitis, but benefits are also seen in nonperforated appendicitis and even in those with a normal appendix. In elective colorectal operations, it has been established that all patients should receive prophylactic antibiotics. The choices are an oral bowel preparation consisting of neomycin or kanamycin combined with erythromycin or metronidazole; a parenteral antimicrobial drug such as cefoxitin or cefotetan; or a combined oral/parenteral regimen. Risk factors for postoperative wound infection include a prolonged duration of surgery (greater than 3.5 hours) and rectal resection. The most popular prophylactic regimen employed by American surgeons, particularly in the presence of adverse risk factors, is oral neomycin/erythromycin along with a short course (one to three doses) of a systemic cephalosporin active against anaerobes.

The oxidative metabolic activity of granulocytes can be directly examined by chemiluminescence, a laboratory technique that measures photon emission during well-defined inflammatory or microbicidal events. Numerous studies have utilized chemiluminescence to examine early changes during infectious diseases and other pathologic processes. Studies have suggested that receptors on cell surfaces and oxygenation of granulocytes can reflect the severity of disease as well as provide early diagnostic information. Diseases within virtually every subspecialty of medicine have been studied in this respect, but most investigations have focused on infectious and autoimmune conditions. The present review summarizes current progress in laboratory methods and evaluates the potential application of recently published clinical data. It is apparent that during disease myeloperoxidase- and oxidase-dependent oxygenation activities reflect separate host responses, and independent measurements of these activities will offer a more meaningful understanding of host defense. Immune complexes and other factors in serum may also interact with granulocytes to alter the receptors on cell surfaces and subsequent metabolic activity. In some circumstances, enhanced function of granulocytes may be detrimental to the host.

In 1987 an outbreak of illness due to Listeria monocytogenes occurred in Philadelphia. In contrast to previously studied outbreaks, no source of infection or vehicle of transmission could be identified, and several listerial strains were found to be involved. A hypothesis that was developed and eventually published suggests that clinical listeriosis may occur when individuals who are asymptomatic for listerial infection but whose gastrointestinal tract has been colonized by Listeria organisms become infected with another pathogen. The case of a farmer who developed a brain stem abscess due to L. monocytogenes following an episode of acute enteritis due to Shigella sonnei lends support to this hypothesis.

A patient with spina bifida secondary to an Arnold-Chiari deformity experienced seven episodes of sustained bacteremia due to Staphylococcus aureus over 2 years. Despite an extensive diagnostic evaluation the source of the recurrent bacteremia remained obscure. The patient's mother eventually recalled that a procedure for replacement of a ventriculoatrial shunt performed 16 years earlier had been complicated by retention of a shunt fragment in the bloodstream. Standard radiographic techniques failed to identify an intravascular foreign body; however, ultrafast computerized tomography of the heart demonstrated a density in the right atrium. Atriotomy was performed and a plastic catheter fragment was excised. Bacteremia has not recurred during a follow-up period of 24 months. Patients with recurrent unexplained bacteremia should be evaluated carefully for the presence of occult intravascular catheter fragments that may be retained after surgical procedures or intravascular instrumentation. Ultrafast computed tomographic scanning of the heart is a useful technique for detecting intracardiac catheter fragments.