Potential virulence-associated factors in Brazilian purpuric fever. Brazilian Purpuric Fever Study Group

Carlone, George M.; Gorelkin, Leo; Gheesling, Linda L.; Erwin, Alice L.; Hoiseth, Susan K.; Mulks, Martha H.; O'Connor, S P; Weyant, Robbin S.; Myrick, J. E.; Rubin, Lorry G.

doi:10.1128/jcm.27.4.609-614.1989

Cited by 33 publications

(23 citation statements)

References 30 publications

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“…The infant rat model had previously been shown to be useful for studying Hib pathogenesis, making it attractive for studying the BPF clone (54). Initial observations that the BPF clone was more virulent in this model than were control strains of H. aegyptius supported the notion that the BPF clone had unidentified virulence factors (13,52). For example, bacteremia was detected at 24 h in 66% (38 of 58) of infant rats inoculated intraperitoneally with one of three BPF clone isolates compared to 2% (1 of 59) animals inoculated with a non-BPF clone isolate.…”

Section: Bpf Clone Virulence Factorsmentioning

confidence: 81%

“…A 145-kDa conserved phase-variable surface protein present in BPF clone strains did not contribute to virulence in an infant rat model (49,50). There are genetic and antigenic differences between the IgA1 protease produced by the BPF clone and those produced by non-BPF clone strains of H. aegyptius (13,34). Although this supports the clonal nature of BPF-causing strains, there are no data to suggest that differences in IgA1 protease contribute to BPF pathogenesis.…”

Section: Other Potential Virulence Factorsmentioning

confidence: 88%

“…However, this carbohydrate-reactive material was evident only after the BPF clone had been passaged in mice and the amount of staining was substantially less than what was observed with a Hib control strain. In addition, ruthenium red staining is not specific for the presence of polysaccharide capsule (13). Third, the H. influenzae cap probe was found to hybridize with BPF clone DNA but not with the DNA of non-BPF clone strains, suggesting the presence of H. influenzae cap genes (13).…”

Section: Bpf Clone Virulence Factorsmentioning

confidence: 92%

“…In addition, ruthenium red staining is not specific for the presence of polysaccharide capsule (13). Third, the H. influenzae cap probe was found to hybridize with BPF clone DNA but not with the DNA of non-BPF clone strains, suggesting the presence of H. influenzae cap genes (13). Invasive H. influenzae strains are encapsulated and are of one of six capsular serotypes (a to f); these strains share the cap genes, which are required for encapsulation.…”

Section: Bpf Clone Virulence Factorsmentioning

confidence: 97%

“…However, it was subsequently shown that selective hybridization of the H. influenzae cap probe to the BPF clone strains was due to the presence of insertion element IS1016, which is situated at the cap loci of some Hib strains (19,24,31). Despite the presence of this insertion element, the BPF clone was found to not have the capsular genes that are found in H. influenzae serotypes a to f. In another study, attempts to isolate acidic polysaccharide were unsuccessful (13). Therefore, at present there is no firm evidence that the BPF clone is an encapsulated organism.…”

Section: Bpf Clone Virulence Factorsmentioning

confidence: 99%

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Emergence and Disappearance of a Virulent Clone of Haemophilus influenzae Biogroup aegyptius, Cause of Brazilian Purpuric Fever

2008

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SUMMARY In 1984, children presented to the emergency department of a hospital in the small town of Promissão, São Paulo State, Brazil, with an acute febrile illness that rapidly progressed to death. Local clinicians and public health officials recognized that these children had an unusual illness, which led to outbreak investigations conducted by Brazilian health officials in collaboration with the U.S. Centers for Disease Control and Prevention. The studies that followed are an excellent example of the coordinated and parallel studies that are used to investigate outbreaks of a new disease, which became known as Brazilian purpuric fever (BPF). In the first outbreak investigation, a case-control study confirmed an association between BPF and antecedent conjunctivitis but the etiology of the disease could not be determined. In a subsequent outbreak, children with BPF were found to have bacteremia caused by Haemophilus influenzae biogroup aegyptius (H. aegyptius), an organism previously known mainly to cause self-limited purulent conjunctivitis. Molecular characterization of blood and other isolates demonstrated the clonal nature of the H. aegyptius strains that caused BPF, which were genetically distant from the diverse strains that cause only conjunctivitis. This led to an intense effort to identify the factors causing the unusual invasiveness of the BPF clone, which has yet to definitively identify the virulence factor or factors involved. After a series of outbreaks and sporadic cases through 1993, no additional cases of BPF have been reported.

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Section: Bpf Clone Virulence Factorsmentioning

confidence: 81%