Search PubMed⌕ Search

Biomedical subjects

J J LiPuma

Publications and source records attributed to J J LiPuma.

48 records · Page 3Linked to original sources
PubMed1991

Clinically inapparent meningitis complicating periorbital cellulitis.

Two young children with periorbital (preseptal) cellulitis were found to have meningitis despite having no signs of meningeal irritation and normal cerebrospinal fluid (CSF) cell counts and chemistries. These cases are reported to remind physicians caring for acutely ill children that periorbital cellulitis can have life-threatening complications and that meningitis can occur in the absence of significant clinical signs and in the presence of an initially normal CSF.

Cellulitis↗
PubMed1991

A novel approach to insertional mutagenesis of Haemophilus influenzae.

Insertional mutagenesis of the Haemophilus influenzae chromosome was accomplished by a novel method employing a 2.2-kbp element, TSTE. This element, consisting of the neo gene of Tn5 flanked by Haemophilus-specific uptake sequences, was ligated to circularized chromosomal fragments before transformation into the homologous strain. Eight mutants defective in the production of haemocin were detected. This strategy provides an efficient mechanism for the insertional mutagenesis of H. influenzae.

DNA Transposable Elements↗
PubMed1990

Person-to-person transmission of Pseudomonas cepacia between patients with cystic fibrosis.

Ribotyping, a method of strain identification based on analysis of bacterial genomic restriction fragment length polymorphisms, was used to investigate the acquisition of Pseudomonas cepacia by a patient with cystic fibrosis. Analysis of isolates recovered from the index patient and his contacts showed person-to-person transmission of this opportunist organism. This documentation of the transmission of P cepacia from one cystic fibrosis patient to another suggests that measures to limit the acquisition of the pathogen by patients with cystic fibrosis may be worth while.

Adult↗
PubMed1990

In-vitro activities of trospectomycin, cefpodoxime, and second-generation cephalosporins against Haemophilus influenzae type b.

The in-vitro activities of trospectomycin, cefpodoxime, cefamandole, cefonicid, and cefuroxime against beta-lactamase-negative and -positive invasive clinical isolates of Haemophilus influenzae type b were determined by the agar dilution method. Trospectomycin and cefpodoxime inhibited 90% of the strains at concentrations of 5 and 0.06 mg/l, respectively, and no differences between the susceptibilities of the beta-lactamase-negative and -positive strains were noted. The activity of cefpodoxime was minimally affected by increased inoculum size, but significant inoculum effects were noted with cefamandole, cefonicid, and cefuroxime with beta-lactamase positive strains.

Anti-Bacterial Agents↗
PubMed1990

Haemocin, the bacteriocin produced by Haemophilus influenzae: species distribution and role in colonization.

Four hundred thirty-eight strains of Haemophilus influenzae were examined for production of and sensitivity to haemocin, a bacteriocin produced by some members of this species. Whereas 199 of 212 (94%) type b isolates produced haemocin, 131 of 134 (98%) nontypeable and 91 of 92 (99%) encapsulated non-type b isolates were sensitive to haemocin. Among strains previously genetically characterized by multilocus enzyme electrophoresis, haemocin production was detected in type b isolates belonging to 25 of 29 (86%) clonally distinct electrophoretic types. None of 60 clonally distinct nontypeable strains produced this substance, and all were sensitive to it in vitro. The genes encoding haemocin production were transformed independently of the genes necessary for capsule expression from a prototypic type b strain to a nontypeable strain. After intranasal inoculation of infant rats with an equal mixture of a non-haemocin-producing strain and its haemocin-producing transformant, organisms capable of haemocin production predominated in both nasopharyngeal and blood cultures. These data demonstrate that haemocin production is strongly associated with type b encapsulated members of this species and suggest a mechanism by which haemocin might play a role in host nasopharyngeal colonization by this pathogen.

Animals↗
PubMed1989

Reactivity of Haemophilus influenzae type b anti-pili antibodies.

The reactivity of anti-pilus antibodies to native and denatured Haemophilus influenzae b (Hib) pili was studied using rabbit serum prepared against piliated H. influenzae b strain M43 (p+) and adsorbed with its non-piliated variant, strain M42 (p-). The specificity of the adsorbed serum for Hib pili was documented by immunogold electron microscopy and by immunoprecipitation, which revealed the 24 kDa pilin band from strain M43 (p+) that was not seen on strain M42 (p-). In immunodot assays, the anti-pilus antibodies reacted with the native pili present on the outer membrane of strain M43 (p+), but on Western blot assay using denatured outer membranes, the anti-pilus antibodies did not react with the 24 kDa pilin subunit. These data demonstrate that the anti-pilus antibodies in the adsorbed serum recognize conformational epitopes that depend on the tertiary or quaternary structure of Hib pili.

Agglutination↗
PubMed1989

DNA polymorphisms among Escherichia coli isolated from bacteriuric women.

Restriction fragment length polymorphism (RFLP) patterns, plasmid profiles, and antimicrobial susceptibility patterns of paired sequential Escherichia coli isolates from antibiotic-treated and untreated elderly women were analyzed. Isolates from 26 of 27 subjects who were treated successfully with antibiotics but became reinfected differed by RFLP analysis, whereas 10 of 12 subjects who failed treatment and 11 of 14 untreated subjects had paired isolates with identical RFLP banding patterns. Only 40 of the 53 pairs of isolates could be analyzed by plasmid profiles; 36 of these 40 were concordant with RFLP analysis. Antimicrobial susceptibility patterns showed poor concordance with RFLP analysis. This study demonstrates the utility of RFLP analysis and indicates that isolation of E. coli from elderly women after sterilization of the urinary tract usually results from introduction of a new strain; elderly women who fail antibiotic therapy or receive no therapy may remain persistently infected with the same E. coli strain.

Aged↗
PubMed1988

A broad-spectrum probe for molecular epidemiology of bacteria: ribosomal RNA.

We investigated the use of ribosomal RNA (rRNA) as a probe for molecular epidemiology of bacterial pathogens. The chromosomal DNA of Escherichia coli, Pseudomonas cepacia, and nontypable Haemophilus influenzae was digested with EcoRI. Agarose gel electrophoresis, Southern blotting, and hybridization by 32P-labeled rRNA revealed eight to 13 bands. The P. cepacia and H. influenzae banding patterns, observed by using an E. coli rRNA probe, were identical to those produced with homologous rRNA probes. Polymorphism of several hybridization bands distinguished all E. coli isolates, nine of 10 H. influenzae isolates, and seven of eight P. cepacia isolates. Two to four bands were common to all P. cepacia and E. coli isolates. The banding patterns of H. influenzae isolates cultured from the trachea and blood of an infant and from the mother's cervix were identical. These data demonstrate that this method is a widely applicable system for determining the molecular epidemiology of genetically diverse gram-negative organisms.

DNA Restriction Enzymes↗
PubMed1988

Structural and serological relatedness of Haemophilus influenzae type b pili.

The structural and serological relatedness of the pilus proteins of several isolates of Haemophilus influenzae type b cultured from patients with invasive disease and from different anatomic sites within the same patient was examined. Epithelial cell-adherent variants of 25 nonadherent parent isolates were obtained by selection for organisms that adhered to human erythrocytes. Outer membrane protein analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of an additional 24- to 24.5-kilodalton protein among all adherent variants but absent from all nonadherent parent isolates. Polyclonal rabbit antiserum against the intact native pilus protein of H. influenzae M43 cross-reacted with 20 of 25 adherent H. influenzae in both immunodot and slide-agglutination assays. No differences in reactivity among isolates cultured from more than one anatomic site in the same patient were noted. Anti-M43 pilus antiserum had bactericidal activity against both the homologous strain and a heterologous strain that demonstrated serologic identity in the immunodot and slide agglutination assays. The adherence of these strains to human epithelial cells in vitro was inhibited by Fab fragments purified from the antipilus antiserum. These data indicate that a remarkable degree of homogeneity in pilin subunit size exists among the pili of H. influenzae type b and that major antigenic determinants are shared among most of these pili. Also, antibodies directed against H. influenzae pilus proteins may be able to contribute to host defenses through serum bactericidal activity and by blocking the adherence of this bacterium to host epithelial cells.

Antibodies, Bacterial↗
PubMed1987

Role of capsule in adherence of Haemophilus influenzae type b to human buccal epithelial cells.

The role of capsule in the adherence of Haemophilus influenzae type b to human epithelial cells in vitro was examined. A group of 30 nonadherent isolates did not differ in degree of encapsulation compared with their respective adherent variants. Furthermore, capsule-deficient mutants of both nonadherent and adherent variants did not differ significantly in degree of adherence compared with their respective encapsulated parents. These data indicate that capsule does not significantly influence the adherence of H. influenzae type b to human epithelial cells.

Bacterial Adhesion↗