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Biomedical subjects

A L Bisno

Publications and source records attributed to A L Bisno.

At least 19 recordsLinked to original sources
PubMed1997

Diagnosis and management of group A streptococcal pharyngitis: a practice guideline. Infectious Diseases Society of America.

This is the second in a series of practice guidelines commissioned by the Infectious Diseases Society of America through its Practice Guidelines Committee. The purpose of these guidelines is to provide assistance to clinicians when making decisions on treating the conditions specified in each guideline. The targeted providers are pediatricians, family practitioners, and internists. The targeted patients and setting for the acute pharyngitis guideline are pediatric, adolescent, and adult outpatients with a complaint of sore throat. Funding was provided by the IDSA. Panel members represented experts in adult and pediatric infectious diseases. The guidelines are evidence-based. A standard ranking system was used for the strength of the recommendations and the quality of the evidence cited in the literature reviewed. The document has been subjected to external review by peer reviewers as well as by the Practice Guidelines Committee and was approved by the IDSA Council. An executive summary, algorithms, and tables highlight the major recommendations. Indicators of quality will assist in guideline implementation. The guideline will be listed on the IDSA home page at http://www.idsociety.org.

Adolescent↗
PubMed1997

Murine model of recurrent group G streptococcal cellulitis: no evidence of protective immunity.

Despite the well-known tendency of cellulitis due to beta-hemolytic streptococci to recur, little is known regarding the mechanisms of human immunity to this infection. We established cellulitis in mice by using a strain of group G streptococcus (1750) originally isolated from the bloodstream of a patient with acute cellulitis. This strain, which has been studied extensively in our laboratory, expresses M protein structurally and functionally analogous to that of group A streptococci, and we have cloned and sequenced the gene encoding this protein (emmMG1). Mice injected with 5 x 10(7) CFU of strain 1750 developed nonlethal necrotic skin and soft tissue infections that healed spontaneously after 14 to 16 days. After healing, the mice were repetitively reinoculated three times with the same challenge dose of 1750. Lesion size did not decrease in severity, size, or time to healing after repetitive challenge. The maximum lesion size and tissue concentration of microorganisms increased between the first and fourth challenges. Pretreatment of 1750 cells with opsonic antisera to MG1 diminished neither the maximum lesion size nor the time course of evolution of the lesions. Thus, in the mouse model used here, there was no evidence of acquired protective immunity to experimentally induced cellulitis.

Animals↗
PubMed1996

Identification of a fibronectin-binding protein (GfbA) in pathogenic group G streptococci.

Attachment to eukaryotic cell surfaces is an essential step in the establishment of colonization and infection by bacterial pathogens. This report examines the adherence capabilities of pathogenic group G streptococci and demonstrates that certain group G streptococcal clinical isolates express a fibronectin-binding protein. This protein, termed GfbA for group G streptococcal fibronectin-binding protein, mediates adherence to human skin fibroblasts (HSF). The gene encoding this protein, gfbA, was isolated, and the complete DNA sequence of gfbA was determined. From this sequence GfbA was predicted to be a 580-amino-acid protein (molecular weight = 64,979) with significant amino acid identity to the group A streptococcal fibronectin-binding proteins SfbI and protein F (PrtF) (76 and 78% identity, respectively). GfbA contains regions with notable identity to the fibronectin-binding repeat domains of PrtF. gfbA(+) strains were able to bind to HSF, and preincubation of the gfbA(+) strains with fibronectin blocked this adherence. In addition, gfbA(+) strains were able to bind radiolabeled fibronectin, and this binding was inhibited with addition of excess unlabeled fibronectin. gfbA-negative strains were not able to bind either the HSF or radiolabeled fibronectin. DNA homologous to gfbA was found in 36% of the group G streptococcal isolates examined. Since not all group G streptococcal strains examined contained gfbA, this suggests there might be other tissue-specific adherence molecules expressed by these pathogenic strains.

Adhesins, Bacterial↗
PubMed1996

M proteins of group C streptococci isolated from patients with acute pharyngitis.

We studied 15 strains of group C (Streptococcus equi subsp. equisimilis) [corrected] isolated from the throats of college students with acute pharyngitis and 5 strains isolated from patients with noninfectious problems. Nineteen of the 20 strains resisted phagocytic killing during incubation in normal human blood, suggesting that they might express M proteins. Genomic DNA from all 20 strains hybridized with a probe corresponding to the carboxyterminal one-third of the group A M-protein gene emm24, a region that is highly conserved among M proteins of group A and group G streptococci. The DNA sequences of the N-terminal (variable) regions of the M-protein-encoding genes from two disease-associated group C isolates and one control isolate were determined. The predicted amino acid sequences of the two pharyngitis strains were identical and were 88% homologous to the amino acid sequence of a group G M-protein gene. The predicted terminal amino acid sequence of the control strain does not correspond to any such sequences in the GenBank database. All three strains studied possess the conserved region domain common to class I group A M-protein types epidemiologically associated with rheumatic fever. These studies demonstrate the presence of M proteins in strains of S. equi subsp. equisimilis [corrected] isolated in cases of endemically occurring acute pharyngitis. Certain of these proteins are similar to those of group G streptococci, while others may represent new M types. The similarity in structure and function between M proteins of nonrheumatogenic serogroups and those of rheumatogenic group A streptococci suggests that factors other than or in addition to M protein per se are likely involved in the pathogenesis of rheumatic fever.

Acute Disease↗
PubMed1995

Antibiotic treatment of adults with infective endocarditis due to streptococci, enterococci, staphylococci, and HACEK microorganisms. American Heart Association.

OBJECTIVE: To provide guidelines for the treatment of endocarditis in adults caused by the following microorganisms: viridans streptococci and other streptococci, enterococci, staphylococci, and fastidious gram-negative bacilli of the HACEK group. PARTICIPANTS: An ad hoc writing group appointed by the American Heart Association under the auspices of the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young. EVIDENCE: Published studies of the treatment of patients with endocarditis and the collective clinical experience of this group of experts. CONSENSUS PROCESS: The recommendations were formulated during meetings of the working group and were prepared by a writing committee after the group had agreed on the specific therapeutic regimens. The consensus statement was subsequently reviewed by standing committees of the American Heart Association and by a group of experts not affiliated with the working group. CONCLUSIONS: Sufficient evidence has been published that recommendations regarding treatment of the most common microbiological causes of endocarditis (viridans streptococci, enterococci, Streptococcus bovis, staphylococci, and the HACEK organisms) are justified. There are insufficient published data to make a strong statement regarding the efficacy of specific therapeutic regimens for cases of endocarditis due to microorganisms that uncommonly cause endocarditis. As a useful aid to the practicing clinician, the writing group developed a consensus opinion regarding management of endocarditis caused by the most commonly encountered microorganisms and regarding those cases due to infrequent causes of endocarditis.

Adult↗
PubMed1995

Molecular aspects of bacterial colonization.

Bacteria have developed a wide variety of molecular mechanisms that permit firm adherence to a biologic surface. This review summarizes basic principles involved in this process, as exemplified by adherence of the group A streptococcus to oral epithelium, staphylococci to indwelling prostheses, and Escherichia coli to uroepithelium and enterocytes.

Bacterial Adhesion↗
PubMed1995

M proteins of group G streptococci: mechanisms of resistance to phagocytosis.

Group G streptococci that express M protein and resist phagocytosis in human blood (virulent strains) were compared with strains of groups G and A that are readily phagocytosed (avirulent). Virulent group G streptococci were less effective (P < .05) as activators of the alternative complement pathway (ACP) than were avirulent streptococci. In immunofluorescence studies, C3 bound more avidly to avirulent than to virulent group G streptococci. Resistance of virulent group G strains to ACP opsonization and to phagocytosis was markedly diminished by removal with pepsin of the type-specific portion of the M molecule. Preincubation with fibrinogen did not diminish ACP activation or C3 binding by virulent group G and A streptococci but did exert an antiphagocytic effect. Given the similarity of M proteins of groups G and A in structure and function, other microbial constituents are likely responsible for differences in the spectra of illnesses attributable to the two serogroups.

Antigens, Bacterial↗
PubMed1995

Antimicrobial prophylaxis of infection.

Antimicrobial agents are used to prevent infections in a variety of clinical circumstances. In certain instances, the precise indications for prophylaxis remain controversial, and the preferred regimens undergo alterations based upon evolving clinical experience, changing patterns of microbial susceptibility, and innovations in medical and surgical practice. This article outlines the general principles underlying the use of antimicrobial prophylaxis and presents recommendations for the use of such prophylaxis in three areas: (1) surgery involving contaminated, clean-contaminated, and clean procedures; (2) prevention of infections due to specific pathogens, including Neisseria meningitidis, Hemophilus influenzae, Streptococcus pneumoniae, and Streptococcus pyogenes; and (3) prevention of infective endocarditis.

Antibiotic Prophylaxis↗
PubMed1993

Absence of HIV transmission from an infected dentist to his patients. An epidemiologic and DNA sequence analysis.

OBJECTIVE: To determine if a general dentist with human immunodeficiency virus (HIV) infection transmitted HIV to any of his patients. DESIGN: A cohort study in which all patients treated by a dentist who developed the acquired immunodeficiency syndrome (AIDS) were identified and attempts were made to contact all patients for HIV antibody testing. SETTING: A general dentistry clinic operated by the Department of Veterans Affairs in southeastern Florida. PARTICIPANTS: All patients treated by a dentist during the 5 3/4 years before he developed AIDS were identified in a computerized registry of dental care. MAIN OUTCOME MEASURES: Attempts were made to contact all living patients for counseling and HIV antibody testing. Living patients with newly identified HIV infection were interviewed, and DNA sequence analysis was performed to compare genetic relatedness of their HIV to that of the dentist. Death certificates were obtained for decreased patients, and the medical records of those with diagnoses suggestive of HIV disease or drug abuse and those dying under the age of 50 years were reviewed in detail. RESULTS: There were 1192 patients who had undergone 9267 procedures, of whom 124 were deceased. A review of the death certificates of the deceased patients identified five who had died with HIV infection, all of whom were either homosexuals or users of illicit intravenous drugs. We were able to locate 962 (92%) of the remaining 1048 patients, and 900 agreed to be tested. Infection with HIV was documented in five of the 900 patients, including four who had clear evidence of risk factors for acquiring HIV infection. One patient who had only a single evaluation by the dentist denied high-risk behavior. Comparative DNA sequence analysis demonstrated that the viruses from the dentist and these five patients were not closely related. CONCLUSION: This study indicates that the risk for transmission of HIV from a general dentist to his patients is minimal in a setting in which universal precautions are strictly observed. Programs to ensure compliance with universal precautions would appear preferable to programs for widespread testing of dentists.

Cohort Studies↗
PubMed1993

Discontinuing rheumatic fever prophylaxis in selected adolescents and young adults. A prospective study.

OBJECTIVE: To assess the safety of discontinuing prophylaxis with antimicrobial agents in patients judged to be at relatively low risk for recurrence of acute rheumatic fever. DESIGN: Observational cohort study. SETTING: Public health clinics in the Southeast Health District of Santiago, Chile. PATIENTS: Fifty-nine patients (19 men, 40 women) ranging in age at study entry from 15 to 44 years (mean, 24.5 years). Forty-eight had completed their prescribed period of prophylaxis. Eleven refused or were allergic to intramuscular benzathine penicillin G and were non-compliant with oral sulfadiazine. INTERVENTION: In patients who did not have carditis during their previous attack(s), prophylaxis was discontinued after 5 years or at age 18, whichever was longer. In those with only mild mitral regurgitation or healed carditis, prophylaxis was stopped after 10 years or at age 25. Symptomatic intercurrent streptococcal throat infections were treated with antibiotics. MEASUREMENTS: Patients were seen every 3 months during the study (July 1982 to September 1988). For the first 4.25 years, throat cultures as well as sera samples for antistreptolysin O and anti-DNAse B assays were obtained at each visit. RESULTS: During laboratory surveillance, significant increases in antibody titers were detected in 56 instances (28.1 [95% CI, 21.7 to 36.5] per 100 patient-years), and 29 isolations of group A streptococci occurred (14.5 [CI, 10.1 to 20.8] per 100 patient-years). The patients were followed for a total of 3349 patient-months, during which time two acute rheumatic fever recurrences were observed (0.7 [CI, 0.2 to 2.6] per 100 patient-years). No recurrences occurred during an outbreak of acute rheumatic fever in 52 patients in the study area in 1986. CONCLUSIONS: These and other data indicate that acute rheumatic fever prophylaxis can safely be discontinued in young adults judged to be at low risk for recurrence and who are maintained under careful prospective surveillance.

Adolescent↗
PubMed1993

Infections associated with prosthetic devices: clinical considerations.

The successful development of synthetic materials and introduction of artificial devices into nearly all body systems has been shadowed by the adaptation of microorganisms to the opportunities these devices afford for eluding defenses and invading the host. Clinicians are faced with the task of recognizing the manifestations of device-associated infection, predicting the likely pathogens involved, knowing the appropriate diagnostic methods, and initiating appropriate therapy. Infections associated with prosthetic heart valves are particularly challenging to successfully treat; surgical replacement may be necessary. Infection associated with an artificial joint usually requires removal of the device in addition to appropriate antibiotics. Intravascular associated infections are the leading cause of nosocomial bacteremias and, because of their intravascular location, these infections are often life catheter threatening if not promptly diagnosed and treated. Even contact lenses, external to epithelial surfaces, may give rise to serious sight-threatening infections. Although artificial devices play a paramount role in medicine today, infection is an ever present potential with which clinicians must be familiar.

Catheters, Indwelling↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of infective endocarditis. Infectious Diseases Society of America and the Food and Drug Administration.

These guidelines describe the design and implementation of clinical trials to assess the safety and efficacy of anti-infective drugs for the treatment of infective endocarditis. Identification and enrollment of patients in clinical trials is based on a modification of traditional criteria. To accrue a sufficient number of patients, only those with streptococcal or staphylococcal endocarditis should be included in studies. Results of treatment with approved drugs allow for projection of expected bacteriologic cure rates and survival rates. Prospective randomized, double-blind studies are recommended. These guidelines are based on the premise that future protocols may include shorter courses of therapy, combinations of drugs, or progression from parenteral to oral therapy. Clinical response is judged as cure, failure, or indeterminate; there is no "improved" category. Microbiologic response is categorized as eradication, persistence, or relapse. When a patient has shown no clinical evidence of active disease for a protracted period, there may be no need to perform a posttreatment blood culture; for such patients, the microbiologic response is termed presumptive eradication. Several months of follow-up may be necessary to detect late relapses.

Anti-Infective Agents↗
PubMed1992

Group G streptococcal M protein exhibits structural features analogous to those of class I M protein of group A streptococci.

We have previously studied a collection of group G streptococcal strains isolated from bacteremic human infections and demonstrated that such strains resist phagocytosis by human polymorphonuclear leukocytes but are type specifically opsonized by homologous antiserum. We have now performed Southern hybridization analysis on genomic DNA from eight blood isolates. All eight isolates showed DNA homology to a group A emm24 gene probe. The M-protein gene of one of the isolates, strain 1750, has now been isolated. This gene (emmG1) encodes a polypeptide of 67 kDa (MG1) which is reactive with antibodies to the partially purified M protein of the parent strain. The predicted amino acid structure of MG1 demonstrates significant identity with the carboxy terminus (C, D, and anchor domains) of M6 and M24 but only limited identity with the amino terminus (variable portion) of these group A M proteins. Southern hybridization of genomic DNA of the eight group G blood isolates with an emmG1 gene probe indicated there were at least four emm alleles associated with these strains. These studies indicate that M proteins of group G streptococci, like those of group A, are genetically heterogeneous. Moreover, MG1 appears to conform to the recently proposed class I structure of M-protein molecules and thus shares certain distinct structural features with the M proteins of well-established rheumatogenic group A streptococcal serotypes. Further comparison of the structures of group G and group A M proteins of throat and skin isolates may cast light on those configurations of the M protein molecules which are and are not critical for the expression of rheumatogenicity.

Amino Acid Sequence↗