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Biomedical subjects

P Ferrieri

Publications and source records attributed to P Ferrieri.

At least 91 records · Page 5Linked to original sources
PubMed1985

Oculoglandular syndrome caused by Francisella tularensis.

Oculoglandular syndrome developed in a 9-year-old boy with a recent history of tick bites and minor eye trauma. Francisella tularensis was isolated on chemically supplemented chocolate agar from a swab of a conjunctival ulcer and an aspirate of a preauricular lymph node, confirming the diagnosis of tularemia. In addition, a rise in agglutination titer to the pathogen was detected in paired sera. The differential diagnosis of oculoglandular syndrome is discussed, with emphasis on the clinical characteristics which led to the diagnosis of tularemia.

Cellulitis↗
PubMed1985

Enzyme-linked immunosorbent assay for identification and measurement of antibodies to group A streptococcal bacteriophage.

A sensitive enzyme immunoassay (ELISA) was developed to identify and measure antibodies to group A streptococcal bacteriophage hyaluronidase. With a purified preparation of bacteriophage hyaluronidase as the solid-phase antigen, the ELISA was shown to be as specific as and more sensitive than the standard bacteriophage neutralization test for measurement of antibody to bacteriophage. In rabbits immunized with bacteriophage, the ELISA detected antibody earlier than the neutralization assay (7 vs. 11 days) and was able to distinguish IgG and IgM class antibodies. A strong correlation was demonstrated between antibody titers measured by ELISA and bacteriophage neutralization (r = 0.88; P less than 0.001). Preliminary data using the ELISA, modified to measure human antibody to bacteriophage hyaluronidase, indicated that an antibody response of both IgG and IgM classes occurred in humans after group A streptococcal infection. This ELISA provided a sensitive method for detection and measurement of antibody to a specific bacteriophage antigen, which will be useful in the investigation of the role of bacteriophage in the pathogenesis of group A streptococcal infections.

Animals↗
PubMed1984

Group B streptococcal Ibc protein antigen: distribution of two determinants in wild-type strains of common serotypes.

Studies were carried out on the distribution of the Ibc protein antigenic marker in wild-type strains of group B streptococci of diverse serotypes isolated from epidemiological studies. Rabbits were immunized with group B streptococcal strain H36B, a prototype Ib strain, to produce antibody to the Ibc protein antigens. One antiserum (no. 970) contained antibody only against the trypsin-sensitive (TS) portion of the Ibc antigen. A second antiserum (no. 973), however, contained antibody to both the TS and the trypsin-resistant (TR) determinants or components of the antigen. A total of 785 wild-type strains of group B streptococci were serotyped by using antiserum 973 as well as antisera to the polysaccharide types Ia, Ib, II, III, and IV. Remarkably, 59% of all the strains tested (462 of 785) reacted positively with the Ibc antiserum, although not all carried both components of the Ibc antigen. Of the 99 Ib strains examined, 84% carried both TS and TR components. In contrast, 96% of the 202 Ic strains carried only the TR component of the Ibc antigen. Antiserum 970 failed to identify these strains. Routine typing with an antiserum which contains antibodies to only one portion of the Ibc antigen could result in significant serotype misidentification. Differentiation of group B streptococcal strains by the presence or absence of individual TS or TR components of the Ibc antigen could prove to be a useful additional epidemiological and serological marker. It is noteworthy that wild-type Ic strains carry, ordinarily, only the TR component, in contrast to the prototype Ic strain, which possesses the complete Ibc protein antigen. The possible contribution of the Ibc antigen to group B streptococcal virulence is of interest and requires further study.

Antigens, Bacterial↗
PubMed1984

Adherence of Haemophilus influenzae to human epithelial cells.

Haemophilus influenzae organisms, both type b and non-typable strains, were tested for their adherence to human buccal epithelial cells. Adherence was determined by visual examination of gram-stained specimens of epithelial cells following incubation with H. influenzae. Among 36 isolates tested, 2 organisms adhered well to buccal cells; a type b nasopharyngeal isolate showed a mean of 19.94 bacteria per cell and a non-typable throat isolate showed a mean of 37.72 bacteria per cell. These isolates readily hemagglutinated human red blood cells. None of the other 12 type b blood or spinal fluid isolates tested adhered well (range 0.04-1.34 bacteria per cell) nor hemagglutinated red cells. There was no difference in the adherence of H. influenzae to buccal mucosal cells from 6 donors, and no difference between epithelial cells obtained from the buccal or nasal mucosa. Although both type b and non-typable H. influenzae strains appear capable of adhering to human epithelial cells, many strains do not. The role of adherence factors in the maintenance of mucosal colonization with these poorly-adherent strains remains unknown.

Carrier State↗
PubMed1984

Systemic candidiasis in very low-birth-weight infants (less than 1,500 grams).

Previous reports in the literature have documented that systemic infection with Candida albicans in very premature infants is frequently fatal (54%) or associated with significant morbidity in survivors (25%). Five patients with a mean birth weight of 829 g had a diagnosis of systemic candidiasis during their stay in a newborn intensive care unit. All infants survived with minimal sequelae following aggressive early treatment with amphotericin B and 5-flucytosine. A review of these five extremely premature infants and 26 previously reported patients suggests the following: (1) disseminated candidiasis is common in the absence of positive findings in blood, CSF, and/or urine cultures; (2) transient candidemia rarely resolves without therapy; (3) meningitis and osteoarthritis occur more frequently than in older patients with disseminated disease; and (4) premature infants tolerate amphotericin B and 5-flucytosine well. Infants who are found to have systemic cultures positive for candidiasis should be treated by (1) removing all factors that predispose to systemic candidiasis (eg, indwelling catheters, broad-spectrum antibiotics); (2) early initiation of systemic antifungal therapy with amphotericin B and 5-flucytosine; and (3) searching for additional foci of disease. After the disease is recognized and treatment is prompt and aggressive, outcome can be substantially improved.

Amphotericin B↗
PubMed1983

Influence of growth temperature of Escherichia coli on K1 capsular antigen production and resistance to opsonization.

When Escherichia coli strains that produce K1 capsular polysaccharide antigen at 37 degrees C were grown at 22 degrees C, K1 antigen was not detected in the supernatant or washed-cell fraction of broth cultures. Significant amounts of K1 polysaccharide were detected only when the organism was grown at temperatures of 30 degrees C or higher. Rabbits immunized with an E. coli K1 strain (serotype O18ac:K1:H7) grown at 37 degrees C produced agglutinating antibody to somatic antigen and precipitating and agglutinating antibody to capsular K1 antigen; those immunized with this strain grown at 22 degrees C produced antibody to somatic antigen, but not to K1 antigen. Antibody to somatic antigen was markedly reduced by adsorption with the organism grown at 22 degrees C, while antibody to capsular antigen was not. E. coli K1 strains grown at 37 degrees C (K1 present) resisted phagocytosis and killing if they were opsonized solely by the alternative complement pathway (ACP) using magnesium ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid-chelated serum. When these strains were grown at 22 degrees C (K1 absent), they were opsonized efficiently by the ACP (28 versus 94% killing, respectively; P less than 0.001). In addition, a non-K1 mutant of an E. coli K1 strain was opsonized efficiently by the ACP although its encapsulated K1 parent was not. Sensitivity of E. coli strains to the bactericidal activity of serum was observed in strains with and without K1 capsular antigen. These studies demonstrated that production of K1 polysaccharide antigen was regulated by environmental temperature and that K1 capsule plays an essential role in rendering the organism resistant to opsonization by the ACP.

Animals↗
PubMed1983

Biochemical markers of the penicillin-induced L phase of a group B, type III Streptococcus sp.

The penicillin-induced L phase of growth of the group B, type III streptococcal strain 76-043 was examined for biochemical properties used for the identification of group B streptococci. After numerous serial subcultures in the cell wall-defective state, this stable L phase continued to produce hemolysin, hippuricase, and CAMP factor in addition to the group- and type-specific antigens. Hemolysin production by the L-phase cells was observed on solid and in liquid media containing sheep erythrocytes. Washed whole L-phase cells hydrolyzed hippuric acid. CAMP factor was detected by the characteristic hemolysis produced on blood agar by L-phase cells or filtered culture supernatants. CAMP factor activity was quantitated by an agar well diffusion system and a macrotube assay with partially purified preparations of CAMP factor and staphylococcal beta-hemolysin. Hyperimmune cow serum neutralized the CAMP activity of the L phase and parent bacterial phase to the same degree, suggesting identity of the CAMP factors. Production of hemolysin, hippuricase, and CAMP factor confirmed the bacterial origin of this L phase. Assay for these biological markers could be used to identify L-phase organisms derived from group B streptococci.

Amidohydrolases↗
PubMed1980

Biochemical and immunological characterization of the extracellular nucleases of group B streptococci.

Nearly all group B streptococcal strains representing the five major serotypes were found to produce extracellular nucleases by screening with an agar-well-diffusion technique in DNA-methyl green agar plates. Three different nucleases have been isolated and partially purified by DEAE-and carboxymethyl-cellulose chromatography. They possessed different mobilities on polyacrylamide gel electrophoresis and different molecular weights. These nucleases, designated I, II, and III, are optimally activated by cations of calcium and manganese and exhibited RNase as well as DNase activity. Despite differences in their physical and biochemical properties, nucleases II and III appear antigenically similar, but distinct from nuclease I. These group B streptococcal nucleases are immunologically different from the nucleases of group A streptococci. Neutralizing activity, probably antibody, to nucleases II and III was found in human sera, and was most prevalent in sera of pregnant women colonized with group B streptococci and in their newborn infants.

Bacterial Proteins↗
PubMed1980

The aetiology of acute cervical adenitis in children: serological and bacteriological studies.

Acute cervical adenitis was investigated in 26 children over a 33-month period. Lymph nodes were aspirated and cultured to yield Staphylococcus aureus or group-A streptococci or both from 22 (84.6%) of the aspriates. Mycobacterium kansasii was isolated from one child. By combined culture and serial serological tests (antistreptolysin-O, anti-DNAase B, and anti-NADase), 50% of the cases were found to be associated with streptococcal infection. In a few children, S. aureus was the only organism recovered, and appeared to be the aetiological agent.

Adolescent↗