Grace M. Thorne

Chronic Parvovirus B19 Infection Resulting in Chronic Fatigue Syndrome: Case History and Review

The spectrum of disease caused by parvovirus B19 has been expanding in recent years because of improved and more sensitive methods of detection. There is evidence to suggest that chronic infection occurs in patients who are not detectably immunosuppressed. We report the case of a young woman with recurrent fever and a syndrome indistinguishable from chronic fatigue syndrome. After extensive investigation, we found persistent parvovirus B19 viremia, which was detectable by polymerase chain reaction (PCR) despite the presence of IgM and IgG antibodies to parvovirus B19. Testing of samples from this patient suggested that in some low viremic states parvovirus B19 DNA is detectable by nested PCR in plasma but not in serum. The patients fever resolved with the administration of intravenous immunoglobulin.

Immune response to Escherichia coli O157:H7 in hemolytic uremic syndrome following salmonellosis

Abstract.Escherichia coli O157:H7, a Shiga-like toxin (SLT)-producing enteric pathogen, has been implicated in most cases of post-diarrheal hemolytic uremic syndrome (D+HUS). Infection with other bacterial pathogens such as Salmonella has also preceded D+HUS episodes, leading to speculation that these organisms may also be etiological. We present two children with unrelated D+HUS following salmonellosis. Both children had negative stool cultures on sorbitol-MacConkey agar soon after the onset of diarrhea. After the diagnosis of HUS, both patients had repeat stool cultures positive for Salmonella alone. Polymerase chain reactions for SLT I and II gene sequences in Salmonella isolates were negative. Enzyme-linked imunosorbent assay for specific humoral response to E. coli O157:H7 lipopolysaccharide in acute and convalescent serum samples revealed evidence of heretofore undetected E. coli O157:H7 infection contemporaneous with each D+HUS episode. These cases demonstrate that isolation of only non-SLT-producing microbes from children with D+HUS should raise suspicion of concurrent undetected infection with SLT-producing organisms. Assaying specific immune response to E. coli O157:H7 can be an important epidemiological adjunct. Bacterial infection with non-SLT-producing Salmonella may represent concomitant enteric pathology rather than D+HUS-instigating infection.

Impaired Innate Immunity in the Newborn: Newborn Neutrophils Are Deficient in Bactericidal/Permeability-Increasing Protein (BPI)

OBJECTIVE The mechanisms by which newborns are at increased risk for invasive bacterial infections have been incompletely defined. A central element of innate immunity to bacterial infection is the neutrophil-a cell that contains cytoplasmic granules replete with antibiotic proteins and peptides. The activity of adult neutrophils against gram-negative bacteria is believed to depend to a significant degree on the presence in neutrophil primary (azurophilic) granules of the 55-kDa bactericidal/permeability-increasing protein (BPI), which binds with high affinity to bacterial lipopolysaccharides and kills gram-negative bacteria. In light of the importance of BPI to antibacterial host defense and to investigate possible factors underlying the risk of neonatal bacterial infections, we determined the relative content of BPI in the neutrophils of adults and newborns. DESIGN The cellular content of BPI was determined by Western blotting of neutrophils derived from full-term newborn cord blood (n = 21; mean gestational age: 38.6 weeks) and from adult peripheral blood (n = 22; mean age: 29 years). Extracellular levels of BPI in adult and newborn plasma were assessed by enzyme-linked immunosorbent assay. Neutrophil content of other azurophil granule markers also was assessed: myeloperoxidase by Western blotting and defensin peptides by acid-urea polyacrylamide gel electrophoresis and Coomassie staining. Acid extracts of newborn and adult neutrophils were analyzed for antibacterial activity against serum-resistant encapsulated isolate Escherichia coli K1/r. RESULTS The neutrophils of newborns contain at least threefold to fourfold less BPI per cell than adult neutrophils (67 +/- 13 ng per 10(6) cells vs 234 +/- 27 ng per 10(6) cells). The relative BPI-deficiency of newborn neutrophils apparently was not attributable to perinatal stress-related degranulation of intracellular BPI stores because: 1) newborn and adult neutrophils contained nearly identical amounts of 2 microbicidal constituents derived from the same primary (azurophil) granule compartment as BPI (the enzyme myeloperoxidase as well as defensin peptides), and 2) levels of extracellular BPI in newborn plasma, measured by enzyme-linked immunosorbent assay, represent only approximately 2% of cellular BPI content. As predicted by their lower BPI content, newborn neutrophil acid extracts demonstrated significantly lower antibacterial activity against E coli K1/r than did adult neutrophil acid extracts. CONCLUSION These data suggest that the neutrophils of newborns are selectively deficient in BPI, a central effector of antibacterial activity against gram-negative bacteria. BPI deficiency correlates with decreased antibacterial activity of newborn neutrophil extracts against serum-resistant E coli and could contribute to the increased incidence of gram-negative sepsis among newborns relative to healthy adults.neonatal sepsis, gram-negative bacteria, endotoxin, neutrophil, polymorphonuclear leukocyte, innate immunity, bactericidal/permeability-increasing protein, defensin, myeloperoxidase.

Performance of a solid phase enzyme immunoassay for detection of group A streptococci in a pediatric office laboratory as refereed by a hospital laboratory.

We evaluated the performance of a new rapid solid phase enzyme immunoassay, SUDS Group A Strep (MUREX Corp., Norcross, GA) for the detection of Group A beta-hemolytic streptococci in a pediatric office practice. Duplicate throat swabs were obtained from 341 children with pharyngitis. One swab was used in the SUDS test and the other was cultured in the office laboratory. Office SUDS and culture (sheep blood agar plate, aerobic 24-hour incubation) were compared with culture using reference techniques (sheep blood agar plate, anaerobic 48-hour incubation) in a hospital laboratory. Compared with hospital laboratory culture, the sensitivity of office SUDS (73.8%) was superior to that of office culture (66.6%) at P = 0.05. Specificities were 93.1 and 98.6%, respectively; positive predictive values were 86.1 and 96.6%; and negative predictive values were 85.9 and 83.5%. The sensitivity and specificity of SUDS compared with office culture were 88.5 and 87.8%, respectively, but would have been 93 and 94% had hemolyzed media not been used on several occasions in the office culture procedure. We conclude that SUDS Group A Strep was significantly more sensitive than throat cultures as performed in a typical pediatric practice although the performance of office cultures could have been improved by standard quality control techniques.

Salmonella: The chickens and the eggs

Abstract While poultry meat remains a major vehicle for human salmonella infections, epidemiologic data indicate that the current increase in outbreaks of SE arises from an important new source—intact shell eggs. Studies in the U.S. and U.K. have documented the ability of SE to cause invasive disease in young and old hens (i.e., infection of ovaries, oviducts, and peritoneum that allow for transovarian infection of the developing ovum prior to shell deposition). The persistence of the disease in chickens, and the immune response to various serotypes of SE are unknown and need to be addressed as better test procedures for identifying infected flocks and eggs are designed. Given the probable low minimal infective dose, and the ability of the organism to survive and grow in intact eggs and to survive various cooking procedures, care must be taken in storing and preparing eggs and foods containing eggs. In hospitals, nursing homes, and restaurants, particular care should be taken to reduce the risk of exposure by using pasteurized egg products. The costs of preventing salmonellosis are not known but the cost of a single hospital-based outbreak (involving 242 people and 3 deaths) was estimated to be between

Inability to Detect Respiratory Syncytial Virus in Peripheral Blood Mononuclear Cells of Infants with Bronchiolitis |[dagger]| 893

340,000 and

IMMUNE RESPONSE TO E. COLI O157:H7 IN TWO CHILDREN WITH HEMOLYTIC UREMIC SYNDROME (HUS) FOLLOWING SALMONELLA ENTERITIS. † 2205

1,530,000 at 1985 prices (31). In order to control the rise in SE and eradicate SE from broiler and layer flocks, the basis for the differences in virulence among SE phage types needs to be identified. Such basic information will provide the foundation for specific identification of flocks infected with epidemiologically important strains, and permit the design of suitable systems for intervention and control.

Impaired Innate Immunity in the Newborn: Newborn Neutrophils Are Deficient in Bactericidal/Permeability-Increasing Protein

Inability to Detect Respiratory Syncytial Virus in Peripheral Blood Mononuclear Cells of Infants with Bronchiolitis † 893

Parvovirus B19-associated interstitial lung disease, hepatitis, and myositis

IMMUNE RESPONSE TO E. COLI O157:H7 IN TWO CHILDREN WITH HEMOLYTIC UREMIC SYNDROME (HUS) FOLLOWING SALMONELLA ENTERITIS. † 2205