Search PubMed⌕ Search

Biomedical subjects

P Ferrieri

Publications and source records attributed to P Ferrieri.

At least 55 records · Page 3Linked to original sources
PubMed1994

Scanning electron microscopic evaluation of different endodontic procedures on dentin morphology of human teeth.

Four manual endodontic instruments, an ultrasonic and an endosonic system were studied with a view to evaluating the morphology of the smear layer and the amount of debris and pulpal residues in the apical third of human extracted straight teeth from 55- to 75-yr-old patients. The manual instruments were K files, Ergoflex files used with the step-back technique, Canal Master with its own technique, and Flex-R with the Roane technique. The ultrasonic system was Suprasson Piezo and the endosonic was Excalibur. Human extracted teeth with straight canals were used and examined under a scanning electron microscope. All manual instrumentations showed a homogeneous compact smear layer and no pulp residues. No statistical differences were observed among the four manual techniques. Ultrasonic technique showed the complete removal of the smear layer, leaving small amounts of pulp debris at the apical third, while the Excalibur showed an almost complete elimination of the smear layer, leaving a homogeneous layer of pulpal residues along the canal.

Aged↗
PubMed1994

Guidelines for long-term management of patients with Kawasaki disease. Report from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association.

Long-term management of patients with Kawasaki disease should be tailored to the degree of coronary arterial involvement. This committee has made recommendations for each risk level about antiplatelet and anticoagulant therapy, physical activity, follow-up assessment by a pediatric cardiologist or primary care physician, and the appropriate diagnostic procedures that may be performed to evaluate cardiac disease. The risk level for a given patient with coronary arterial involvement may change over time because of changes in coronary artery morphology. The recommendations for management presented here are intended as practical interim guidelines until additional prospective or retrospective data are compiled to define more clearly the natural history of Kawasaki disease.

Cardiology↗
PubMed1993

Viridans streptococcal shock in bone marrow transplantation patients.

We have recognized a rapidly progressive, often fatal shock syndrome associated with viridans streptococcal sepsis following bone marrow transplantation (BMT). Of 832 patients receiving a marrow transplant at the University of Minnesota between 1976 and 1988, including 123 with viridans streptococcal bacteremia, 10 patients (8%) developed clinical shock within an average of 2 days (range 0-4 days) of their first positive blood culture. Viridans streptococcal shock occurred in patients early in the transplantation course, between 1 and 28 (median 6) days following BMT when all 10 patients were neutropenic. Six of the 10 patients died as a consequence of their shock or from subsequent complications. The most frequent (6 of 10 patients) viridans streptococcal species isolated in the shock patients was Streptococcus mitis. Of multiple factors analyzed for increased risk of developing viridans streptococcal shock, only younger patient age was significantly associated with the development of shock. Although 58% of BMT recipients with viridans streptococcal bacteremia were younger than 15 years, all 10 patients comprising the shock population were < 15 years of age (P < 0.02). We speculate that certain streptococcal strains may trigger fulminant shock in the immunocompromised BMT patient.

Adolescent↗
PubMed1993

Molecular investigation of clinical Enterococcus faecium isolates highly resistant to gentamicin.

Over a 10-month period, 22 beta-lactamase negative E. faecium strains resistant to ampicillin were isolated from severely compromised hospitalized patients. Most isolates were clinically significant. Twenty of these strains were also resistant to extraordinarily high levels of gentamicin, a finding described rarely in E. faecium. By whole-cell DNA restriction endonuclease digestion, the 20 strains with both ampicillin and high-level gentamicin resistance segregated into only 3 different groups, suggesting introduction of limited clones into this population of patients. Plasmid DNA profiles and plasmid DNA restriction enzyme analysis supported this grouping for 18 of these 20 strains, the two remaining isolates had slightly different profiles. Both strains lacking high-level gentamicin resistance had clearly different molecular profiles. The results of hybridization experiments strongly suggested the presence of a similar genetic determinant of high-level gentamicin resistance in E. faecalis and E. faecium. High-level gentamicin resistance in E. faecium was shown to be transferable on conjugative plasmids, so that further dissemination of this resistance trait may be anticipated. Our data indicate that the use of a nucleic acid probe is a promising diagnostic tool for screening both E. faecium and E. faecalis for high-level gentamicin resistance.

Adult↗
PubMed1993

Agrobacterium infections in humans: experience at one hospital and review.

Agrobacteria are noted primarily for their phytopathogenicity and when isolated from human clinical specimens are often considered contaminants or organisms of low pathogenicity. We report six cases at one hospital over a 6 1/2-year period in which infection was accompanied by a compatible clinical syndrome and review 19 cases reported in the literature. Fourteen of the 25 combined cases involved central venous catheter-associated infections. Six cases involved peritonitis, five of which occurred in patients undergoing continuous ambulatory peritoneal dialysis. Additional infections included two non-catheter-associated bacteremias, one prosthetic valve endocarditis, and two urinary tract infections. Most infections were community acquired, and restriction enzyme analysis of Agrobacterium isolates from eight patients at one hospital revealed unique patterns in each case without evidence for clonal dissemination of these strains. Agrobacterium isolates may be resistant to multiple antibiotics, and optimal therapy has not yet been determined. Agrobacteria should be recognized as opportunistic pathogens in the immunocompromised host, particularly in those with indwelling plastic catheters.

Adolescent↗
PubMed1993

Antibody profiles to the group B streptococcal beta antigen in maternal and infant paired sera.

Antibody profiles to the purified beta antigen of the c protein of group B streptococci (GBS) were studied by ELISA and Western immunoblot (WB). The sera from 139 parturient women colonized with GBS, 35 non-colonized parturients and their newborn infants were studied by ELISA; WB was done on 76 maternal and 26 infant sera. Enzyme-labeled anti-IgA (alpha), -IgG (gamma), -IgM (mu), or -IgG (H&L) were used as secondary antibodies. A high prevalence of antibody to the beta antigen was observed by both ELISA and WB among parturient women and their newborns. IgG (H&L) ELISA titers > or = 200 were found in 84% and > or = 800 in 31% of the maternal sera. A significantly higher percentage of women colonized than those non-colonized with GBS had IgG (gamma) titers > or = 800. A significantly higher percentage of women colonized with c protein-positive than c-negative strains of GBS had IgG (H&L) titers > or = 3200. Twelve of 27 women with IgM antibody to the beta antigen also had IgG (gamma) titers > or = 800 and were, in addition, colonized with GBS. Multiple molecular forms of the antigen from 25 to 140 kDa were blotted by the maternal and infant sera. Concordance in the IgG but not in IgA or IgM antibody profiles of maternal and infant paired sera was observed in the overall blotting patterns and ELISA titers. The same titer as the mother was found in 55% of the infant sera and within one dilution in 97%. This suggests active transfer of IgG antibody to the beta antigen across the placenta from mother to baby.

Antibodies, Bacterial↗
PubMed1993

Molecular analysis of multiple isolates of the major serotypes of group B streptococci.

Serotyping of clinical isolates is a widely used technique for epidemiologic study of group B streptococcal infections. However, serotyping cannot definitively determine epidemiologically related or unrelated isolates. We investigated the use of restriction endonuclease analysis (REA) with both conventional agarose gel electrophoresis (AGE) and pulsed-field gel electrophoresis (PFGE) in 50 isolates of the major serotypes of group B streptococci. Single digestion with HindIII and HaeIII and double digestion with HindIII and then EcoRI were used for conventional AGE, and digestion with SmaI was used for PFGE. The molecular profile of one strain was compared with those of the strains within the same serotype as well as with the profiles from strains of different serotypes. Among 10 type Ia, Ia/alpha, Ia/alpha+beta, and Ia/R1 isolates and depending on the restriction enzyme used, we found between five and six REA patterns by conventional AGE and seven by PFGE; among 4 type Ib/alpha+beta isolates we found 2 to 4 REA patterns by conventional AGE and 4 by PFGE; among 21 type II, II/alpha, II/beta, II/alpha+beta, and II/R4 isolates, we found 11 REA patterns by both AGE and PFGE; and among 14 type III, III/R1, and III/R4 isolates, we found from 7 to 12 different REA patterns by AGE and 10 by PFGE. In total, among 13 serotypes and one nontypeable strain, we found 29 to 31 REA patterns by conventional AGE and 33 by PFGE. A particular REA pattern within a serotype was different from the patterns found in the other serotypes, suggesting that REA analysis by using conventional AGE or PFGE is a sensitive method for analyzing genetic relatedness and diversity in group B streptococci and has potential value in molecular epidemiologic studies.

DNA, Bacterial↗
PubMed1993

The microbiologic aspects, including diagnosis, of beta-hemolytic streptococcal and enterococcal infections.

Basic principles concerning the collection, transport, and processing of clinical specimens for the detection of Streptococcaceae are given. Identification of beta-hemolytic streptococci (S. pyogenes, S. agalactiae, Lancefield group C and G streptococci, S. anginosus) and enterococci is based on the careful observation of colony morphology and hemolytic pattern on sheep blood agar plates; subsequent genus or species confirmation is achieved by rather simple biochemical or enzymatic tests and by detection of streptococcal cell wall carbohydrate antigens (Lancefield grouping). Rapid antigen tests for the detection of group A and B streptococci directly from pharyngeal and vaginal swabs, respectively, are highly specific, thus allowing an immediate antibiotic therapy in patients with a positive test result. The reported sensitivities of these nonculture tests are too low to exclude streptococcal colonization or infection, however. The elucidation of the genetics of some major virulence factors of group A and B streptococci has contributed to knowledge of their association with disease, and molecular techniques have supplemented the traditional (mostly culture and serologic) methods for an improved understanding of the epidemiology and pathogenesis of streptococcal infections. Recently employed examples include the M protein gene typing of group A streptococci by oligonucleotide probes and the use of PCR assays for the detection of the genes encoding for the pyrogenic exotoxins. Restriction enzyme endonuclease digestions of bacterial DNA in association with DNA fragment separation by conventional or PFGE have been applied successfully to several species of Streptococcaceae (e.g., S. pyogenes, S. agalactiae). Enterococci are important pathogens in the hospital setting, exhibiting high morbidity and mortality rates in bacteremic patients with severe underlying disease. Molecular typing methods have clearly confirmed their potential to be nosocomially transmitted. E. faecalis and E. faecium still account for the majority of human infections, but some of the newer enterococcal species (at present 19 species are recognized) have been encountered as well. The definitive species identification of enterococci requires the performance of an array of biochemical tests. The increasing antimicrobial resistance of enterococci, including high-level resistance to penicillins and aminoglycosides and occasionally also to glycopeptides, has hampered standard therapeutic regimens. All enterococci isolated from serious infections should be tested for high-level gentamicin and streptomycin resistance by one of several methods evaluated; beta-lactamase production (primarily found in E. faecalis) is reliably detected by the nitrocefin test.(ABSTRACT TRUNCATED AT 400 WORDS)

Enterococcus↗
PubMed1992

Characterization of methicillin-susceptible and methicillin-resistant Staphylococcus aureus isolates by molecular typing methods.

Two groups of clinical Staphylococcus aureus isolates were examined by molecular typing methods. Detailed protocols for the technical procedures are described. By means of plasmid DNA profiles, plasmid DNA restriction enzyme digestion, as well as whole-cell DNA endonuclease digestions subjected to conventional agarose gel electrophoresis and pulsed-field gel electrophoresis, eight methicillin-susceptible S. aureus strains from three patients segregated into three different groups. Consecutive isolates from the same patient revealed identical fingerprints. Generally, good agreement between different molecular typing methods also was achieved in the investigation of 28 methicillin-resistant isolates. However, compared to whole-cell DNA restriction endonuclease analysis, plasmid DNA profiling (all but one strain had detectable plasmid DNA) showed a somewhat greater discriminatory ability. The techniques evaluated were reproducible and relatively easy to perform and provided valuable tools for studying the epidemiology of S. aureus in hospitals.

Bacterial Typing Techniques↗
PubMed1992

Identical genes confer high-level resistance to gentamicin upon Enterococcus faecalis, Enterococcus faecium, and Streptococcus agalactiae.

The structural gene coding for the bifunctional aminoglycoside-modifying 6'-acetyltransferase-2''-phosphotransferase (6'AAC-2''APH) enzyme was specifically amplified by the polymerase chain reaction using template DNA of clinical isolates of enterococci (both Enterococcus faecalis and Enterococcus faecium) and the single high-level gentamicin-resistant Streptococcus agalactiae strain identified thus far. The results of the present study demonstrated that the genes encoding this antibiotic resistance trait are highly homologous in these species. In dot blot hybridization assays using nonradioactively labeled oligonucleotide probes, strains with and without high-level gentamicin resistance could be discerned unequivocally. The gene segment encoding 6'-acetylating activity and the gene segment encoding 2''-phosphorylating activity were simultaneously present in all isolates exhibiting high-level gentamicin resistance.

Acetyltransferases↗
PubMed1992

Similarity between the group B and A streptococcal C5a peptidase genes.

Group B streptococci (GBS) and group A streptococci (GAS) are known to have surface-associated peptidase activity which specifically cleaves C5a (C5a-ase), the primary chemotaxin for polymorphonuclear leukocytes. Amplification products were obtained from GBS genomic DNA template by using the polymerase chain reaction and primers corresponding to the C5a peptidase gene of GAS (scpA12). A restriction map of the GBS full-length amplified gene (scpB) was developed. The scpB restriction map was found to be highly similar to that of the analogous gene in GAS. A 50-bp deletion was located near the 5' end of scpB in a region where repeat sequences are found in scpA12. Hybridization experiments confirmed that other serotypes of GBS also carry an scpB-like gene. These results show that GBS contain a gene, scpB, which is very similar to that harbored by M12 GAS. The probability that scpB encodes the C5a-ase protein is discussed.

Adhesins, Bacterial↗
PubMed1992

Invasive group A streptococcal infections.

Beginning in the mid-1980s and continuing to the present, there has been an apparent increase in the number of severe group A streptococcal infections and their suppurative and nonsuppurative sequelae. The reasons for this epidemiologic change remain incompletely explained. At present, the data seem to suggest that this change is related to the reappearance in the population of not only "new" serotypes, but most likely virulent strains of these serotypes. This has been suggested by available epidemiologic surveys. The pathogenetic mechanism by which these virulent strains cause an increased severity of disease is also incompletely understood. It has been suggested that certain of the streptococcal pyrogenic exotoxins (pyrogenic exotoxin A or B) are associated with strains isolated from severe cases of systemic group A streptococcal infections, but the data conflict in many instances. Clinically, this is an extraordinarily virulent syndrome often leading to the death of the patient within a matter of hours or days. This is despite what would seem to be adequate and appropriate antimicrobial therapy with agents which are effective in vitro against the offending group A streptococcus. Therapy therefore is still based on appropriate antibiotic therapy and support of other systemic manifestations with appropriate medical therapy. At present, prevention of these suppurative and nonsuppurative sequelae is impractical simply because the initial streptococcal infection or colonization is rarely recognized. These events of the last half decade strongly support the need for additional understanding of the epidemiology, pathogenesis, treatment, and prevention of serious group A beta-hemolytic streptococcal infections.

Bacterial Toxins↗
PubMed1992

Laboratory diagnostic methods for central nervous system infections.

Infections of the CNS have a high mortality, and rapid laboratory diagnosis and adequate antimicrobial therapy are critically important for their management. New techniques assist the clinical microbiology laboratory to isolate and identify micro-organisms more rapidly and accurately than with the use of classic procedures. Microbial identification using immunologic and DNA hybridization techniques has importantly reduced the time needed for the diagnosis of infectious diseases. Culture, however, is still the standard method to confirm the identity of an organism isolated from CSF or CNS sites. With the increase in the number of antimicrobial agents and the recognition of resistance in many isolates, antimicrobial susceptibility testing has become extremely important in the selection of optimal antimicrobial therapy. Communication between the physician and the clinical microbiology laboratory is essential for optimum patient care.

Central Nervous System Diseases↗
PubMed1991

Association of exotoxin-producing group A streptococci and severe disease in children.

Clinical features and microbiologic data on all cases of serious (hospitalized) Group A streptococcal infections in children managed at our institution between 1985 and 1988 are presented. All 6 cases were caused by toxin-producing strains. Four of 6 were toxin A-producing strains whereas none of 58 community-acquired (Group A streptococcal) pharyngeal isolates in the same period was a toxin A producer. A review of the literature on the incidence of toxin A-producing strains provides information suggesting a resurgence of such strains in the late 1980s after a relative disappearance of toxin B production in isolates from these patients was also significantly greater than in the isolates acquired from the community in uncomplicated pharyngitis. These findings suggest a role for exotoxin in severe manifestations of Group A streptococcal disease in children.

Adolescent↗
PubMed1991

Isolation of Enterococcus mundtii from normally sterile body sites in two patients.

Enterococcus mundtii, a recently described nonmotile, yellow-pigmented enterococcal species, was isolated from a chronic thigh abscess and from operatively obtained sinus mucosa. It is emphasized that this species may be encountered in clinical specimens and that the correct species identification may be missed when commercially available identification systems are relied on.

Abscess↗