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Biomedical subjects

J M Steckelberg

Publications and source records attributed to J M Steckelberg.

At least 19 recordsLinked to original sources
PubMed2000

Lack of benefit of intravenous immune globulin in a murine model of group A streptococcal necrotizing fasciitis.

Penicillin, clindamycin, and intravenous immune globulin (Venoglobulin-S; IVIG) alone and in combination were studied in a murine model of group A streptococcal necrotizing fasciitis. As assessed by bacterial clearance, treatment with IVIG was not significantly different from no treatment. All treatment regimens that contained penicillin or clindamycin were more effective (P<.05) than no treatment or treatment with IVIG alone. No significant differences were detected among results of treatment with penicillin, penicillin/clindamycin, penicillin/IVIG, clindamycin/IVIG, or all agents combined. Clindamycin alone was less effective than penicillin/IVIG (P=.02), penicillin/clindamycin (P=.009), clindamycin/IVIG (P=.04), or all agents combined (P=.02). No antagonism was observed with the addition of clindamycin or IVIG to penicillin.

Animals↗
PubMed2000

The biopesticide Paenibacillus popilliae has a vancomycin resistance gene cluster homologous to the enterococcal VanA vancomycin resistance gene cluster.

We have previously identified, in Paenibacillus popilliae, a 708-bp sequence which has homology to the sequence of the enterococcal vanA gene. We have performed further studies revealing five genes encoding homologues of VanY, VanZ, VanH, VanA, and VanX in P. popilliae. The predicted amino acid sequences are similar to those in VanA vancomycin-resistant enterococci: 61% identity for VanY, 21% for VanZ, 74% for VanH, 77% for VanA, and 79% for VanX. The genes in P. popilliae may have been a precursor to or have had ancestral genes in common with vancomycin resistance genes in enterococci. The use of P. popilliae biopesticidal preparations in agricultural practice may have an impact on bacterial resistance in human pathogens.

Amino Acid Sequence↗
PubMed2000

Ciprofloxacin inhibition of experimental fracture healing.

BACKGROUND: Fluoroquinolones, such as ciprofloxacin, have an adverse effect on growing cartilage and endochondral ossification in children. This study was carried out to determine whether ciprofloxacin also has an adverse effect on the healing of experimental fractures. METHODS: Sixty male 300-gram Wistar rats were divided equally into three groups, which received ciprofloxacin, cefazolin, or no treatment for three weeks, beginning seven days after production of a closed, nondisplaced, bilateral femoral fracture. The serum concentrations of the ciprofloxacin and the cefazolin were 2.4 and 146 micrograms per milliliter, respectively. Radiographic, histological, and biomechanical studies were used to evaluate fracture-healing. RESULTS: Radiographs revealed significantly more advanced healing of the control fractures compared with the fractures in the ciprofloxacin-treated group (average stage, 2.1 compared with 1.5, p = 0.01). The cefazolin-treated group was not different from the controls with respect to radiographic healing (average stage, 1.8 compared with 2.1, p = 0.18). Torsional strength-testing of fracture callus exposed to ciprofloxacin revealed a 16 percent decrease in strength compared with the controls (284 compared with 338 newton-millimeters, p = 0.04) and a 49 percent decrease in stiffness (twenty compared with thirty-nine newton-millimeters per degree, p = 0.001). The biomechanical strength in the cefazolin-treated group was not different from that of the controls. Fracture calluses in the animals treated with ciprofloxacin showed abnormalities in cartilage morphology and endochondral bone formation and a significant decrease in the number of chondrocytes compared with the controls (0.77 x 10(4) compared with 1.3 x 10(4) cells per square millimeter, p = 0.004). CONCLUSIONS: These data suggest that experimental fractures exposed to therapeutic concentrations of ciprofloxacin in serum demonstrate diminished healing during the early stages of fracture repair. The administration of ciprofloxacin during early fracture repair may compromise the clinical course of fracture-healing.

Animals↗
PubMed2000

Clinical aspects of antimicrobial resistance.

Soon after penicillin was introduced into clinical use, an enzyme (penicillinase) that inactivated it was discovered. Since then, the variety of antimicrobial agents has increased substantially, along with a parallel increase in resistant pathogenic microorganisms. Resistance is now recognized against all available antimicrobial agents. Factors influencing the emergence of resistance include indiscriminate use of antibiotics, prolonged hospitalizations, increasing numbers of immunocompromised patients, and medical progress resulting in increased use of invasive procedures and devices. This article provides an update on clinical aspects of a few commonly found resistant microorganisms relevant to day-to-day clinical practice. A discussion of all resistant organisms is beyond the scope of this report. Both viral and mycobacterial resistance have been addressed in previous articles in this symposium.

Anti-Bacterial Agents↗
PubMed1999

Immunogenicity of three Haemophilus influenzae type b protein conjugate vaccines in HIV seropositive adults and analysis of predictors of vaccine response.

HIV-seropositive adults may be at increased risk of infection due to Haemophilus influenzae type b (Hib) as compared with HIV-seronegative adults. Protein conjugate vaccines have been demonstrated to induce protective levels of antibodies against Hib in immunocompetent infants and also in HIV-seropositive infants. In this study we determined the immunogenicity of three protein conjugate Hib vaccines (PRP-D, HbOC, HbNOMP) in 135 HIV-seropositive adults who received one dose of Hib vaccine. Anti-polyribosylribitol phosphate (PRP) antibodies were measured at 0, 1, 3 and 12 months postimmunization by the Farr method. We demonstrate that all three vaccines are highly immunogenic and result in protective (> 1.0 microg/ml) levels of antibody. Overall the anti-PRP antibody level was > 1.0 microg/ml in 26% of patients preimmunization, 91% at both 1 and 3 months, and 79% at 12 months postvaccination. Comparison of responses to the three vaccines over time demonstrated differences in the mean geometric anti-PRP antibody level at 1 month (p=0.03) and the 12 month time points (p=0.03) with lower geometric mean levels in the HbNOMP group, though baseline differences in groups limit the interpretation of these findings. In a univariate analysis of baseline characteristics which predicted poor vaccine response, low total IgG2 levels preimmunization predicted a poor antibody response at 1 month (p < 0.01) and at 12 months (p=0.05), while low CD4 T-cell count predicted poor response at 12 months (p < 0.01). We conclude that all three US licensed protein conjugate Hib vaccines are immunogenic in HIV-seropositive adults, and that baseline CD4 T-cell count and IgG2 levels predict the likelihood of antibody response to vaccine.

Adult↗
PubMed1999

In vitro activity of linezolid against vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae.

We report the activity of the new oxazolidinone antimicrobial agent linezolid against 37 clinical isolates of vancomycin-resistant enterococci (including organisms carrying the vanA, vanB, vanC-1, and vanC-2/3 genes), 26 clinical isolates of methicillin-resistant S. aureus and 20 clinical isolates of high-level penicillin-resistant S. pneumoniae. All isolates of vancomycin-resistant enterococci were inhibited by < or = 4 ug/ml of linezolid. All isolates of methicillin-resistant S. aureus were inhibited by < or = 8 ug/ml of linezolid. All isolates of penicillin-resistant S. pneumoniae were inhibited by < or = 2 ug/ml of linezolid. Linezolid inhibits strains of multidrug resistant Gram-positive cocci in vitro at concentrations < or = 8 ug/ml.

Acetamides↗
PubMed1999

Ketolide treatment of Haemophilus influenzae experimental pneumonia.

The MICs of HMR 3004 and HMR 3647 at which 90% of beta-lactamase-producing Haemophilus influenzae isolates were inhibited were 4 and 2 micrograms/ml, respectively. Both HMR 3004 and HMR 3647 were active against beta-lactamase-producing H. influenzae in a murine model of experimental pneumonia. As assessed by pulmonary clearance of H. influenzae, HMR 3004 was more effective (P < 0.05) than was azithromycin, ciprofloxacin, clarithromycin, erythromycin A, pristinamycin, or HMR 3647 in this model.

Animals↗
PubMed1999

Staphylococcus lugdunensis endocarditis: a complication of vasectomy?

Three cases of Staphylococcus lugdunensis endocarditis have been reported in patients with a history of vasectomy preceding the development of endocarditis. We describe a new case of a 39-year-old man who developed infective endocarditis due to S. lugdunensis after vasectomy. He was successfully treated with a 7-week course of intravenous antibiotics and subsequently underwent mitral valve reconstruction for severe mitral regurgitation. The present case further supports an association between vasectomy and S. lugdunensis endocarditis.

Adult↗
PubMed1999

Staphylococcus aureus prosthetic joint infection treated with prosthesis removal and delayed reimplantation arthroplasty.

OBJECTIVE: To estimate in patients with Staphylococcus aureus prosthetic joint infection after total hip arthroplasty (THA) or total knee arthroplasty (TKA) the microorganism-specific cumulative probability of treatment failure after prosthesis removal and delayed reimplantation arthroplasty. PATIENTS AND METHODS: All patients with S aureus THA or TKA infection, according to a strict case definition, who were treated with prosthesis removal and delayed reimplantation arthroplasty at Mayo Clinic Rochester between 1980 and 1991 were identified. The study group comprised patients who were free of infection at the time of reimplantation arthroplasty. This cohort was followed up until treatment failure, infection with another organism, prosthesis removal, death, or loss to follow-up occurred. The Kaplan-Meier survival method was used to estimate the cumulative probability of treatment failure. RESULTS: Among 120 S aureus prosthetic joint infections treated with prosthesis removal during the study period, 38 episodes (22 THA, 16 TKA) in 36 patients met the study inclusion criteria. After a median of 7.4 years (range, 0.9 year-16.4 years) of follow-up, treatment failure occurred in 1 (2.6%) of 38 episodes 1.4 years after reimplantation arthroplasty. The 5-year cumulative probability of treatment failure was 2.8% (95% confidence interval, 0%-8.2%). CONCLUSIONS: These data suggest that prosthesis removal and delayed reimplantation arthroplasty is an effective treatment to limit the recurrence of S aureus prosthetic joint infection, provided there is no evidence of infection at the time of reimplantation arthroplasty.

Adult↗
PubMed1999

Artificial Valve Endocarditis Reduction Trial (AVERT): protocol of a multicenter randomized trial.

BACKGROUND AND AIM OF THE STUDY: This article presents the protocol of the Artificial Valve Endocarditis Reduction Trial (AVERT), a multicenter, international randomized trial to assess the efficacy of the SilzoneTM coating of St. Jude Medical Masters Series mechanical heart valves in the prevention of prosthetic heart valve endocarditis (PVE). A total of 4,400 eligible patients will be randomized within three years of study commencement at 17 participating clinical centers in North America and Europe, with study completion within four years. ELIGIBILITY CRITERIA: Eligible patients are candidates for St. Jude mechanical valves with either the Silzone or conventional cuff, in the mitral and/or aortic position, who give informed written consent to participate. Major exclusion criteria are the presence of prosthetic valves that do not require replacement, and the need for tricuspid valve replacement. Bypass surgery and valve repair are allowed during the implant operation. Patients will be randomized using an envelope-based intraoperative randomization scheme, stratified by clinical center and by the presence of endocarditis at the time of surgery. FOLLOW UP: Patients will be contacted at discharge, three months, and each anniversary of the implant procedure. A brief follow up survey, administered via clinic interview, telephone or mail, will elicit events associated with possible endocarditis (unexplained fever, worsening angina, hospitalization) that will initiate contact with the patient's following physician. OUTCOME ANALYSIS: The primary PVE endpoint will be based upon a published algorithm, with two infectious disease specialists making the final determination of cases classified as possible endocarditis. Study data will be periodically reviewed by a Data Safety Monitoring Board. The primary analysis will be an intention-to-treat comparison of freedom from PVE curves between the Silzone and conventional cuff treatment groups. CONCLUSIONS: AVERT will provide much-needed information on the effectiveness of Silzone in preventing PVE, as well as practice patterns and outcomes of valve replacement.

Clinical Protocols↗
PubMed1998

In vitro activity of LY333328 against vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and penicillin-resistant Streptococcus pneumoniae.

We report the activity of LY333328 against 35 clinical isolates of vancomycin-resistant enterococci (including organisms carrying the vanA, vanB, vanC-1, and vanC-2/3 genes, as determined by PCR), 33 clinical isolates of methicillin-resistant S. aureus, and 29 clinical isolates of high-level penicillin-resistant S. pneumoniae. All isolates of vancomycin-resistant enterococci were inhibited by 2 micrograms/mL LY333328, and 8 micrograms/mL LY333328 was bactericidal against all isolates tested. All isolates of methicillin-resistant S. aureus were inhibited by 1 microgram/mL LY333328, and 4 micrograms/mL LY333328 was bactericidal against all methicillin-resistant S. aureus isolates tested. All isolates of penicillin-resistant S. pneumoniae were inhibited by < 0.125 microgram/mL LY333328, and 0.25 microgram/mL LY333328 was bactericidal against all S. pneumoniae isolates tested. LY333328 is a promising new glycopeptide antimicrobial agent.

Anti-Bacterial Agents↗
PubMed1998

Risk factors for prosthetic joint infection: case-control study.

We conducted a matched case-control study to determine risk factors for the development of prosthetic joint infection. Cases were patients with prosthetic hip or knee joint infection. Controls were patients who underwent total hip or knee arthroplasty and did not develop prosthetic joint infection. A multiple logistic regression model indicated that risk factors for prosthetic joint infection were the development of a surgical site infection not involving the prosthesis (odds ratio [OR], 35.9; 95% confidence interval [CI], 8.3-154.6), a National Nosocomial Infections Surveillance (NNIS) System surgical patient risk index score of 1 (OR, 1.7; 95% CI, 1.2-2.3) or 2 (OR, 3.9; 95% CI, 2.0-7.5), the presence of a malignancy (OR, 3.1; 95% CI, 1.3-7.2), and a history of joint arthroplasty (OR, 2.0; 95% CI, 1.4-3.0). Our findings suggest that a surgical site infection not involving the joint prosthesis, an NNIS System surgical patient risk index score of 1 or 2, the presence of a malignancy, and a history of a joint arthroplasty are associated with an increased risk of prosthetic joint infection.

Adolescent↗
PubMed1998

Ceftriaxone once daily for four weeks compared with ceftriaxone plus gentamicin once daily for two weeks for treatment of endocarditis due to penicillin-susceptible streptococci. Endocarditis Treatment Consortium Group.

This randomized, multicenter, open-label study compared the efficacy and safety of monotherapy with 2 g of intravenous ceftriaxone once daily for 4 weeks with those of combination therapy with 2 g of intravenous ceftriaxone and 3 mg of intravenous gentamicin/kg once daily for 2 weeks as therapy for endocarditis due to penicillin-susceptible streptococci. Sixty-one patients were enrolled in the study. Clinical cure was observed for 51 evaluable patients both at termination of therapy and at the 3-month follow-up: 25 (96.2%) of 26 monotherapy recipients and 24 (96%) of 25 combination therapy recipients. Of the 23 patients in each treatment group who were microbiologically evaluable, 22 (95.7%) in each group were considered cured. No patient had evidence of relapse. Fourteen patients (27.5%) required cardiac surgery after initiation of treatment, including five monotherapy recipients and nine combination therapy recipients. Adverse effects were minimal in both treatment groups. We conclude that 2 g of ceftriaxone once daily for 4 weeks and 2 g of ceftriaxone in combination with 3 mg of gentamicin/kg once daily for 2 weeks are both effective and safe for the treatment of streptococcal endocarditis.

Adolescent↗
PubMed1998

Molecular, serological, and clinical features of 16 consecutive cases of invasive streptococcal disease. Southeastern Minnesota Streptococcal Working Group.

We performed a comprehensive analysis of the molecular, serological, and clinical features of 16 consecutive cases of invasive streptococcal disease (ISD). The majority of cases were linked to two group A streptococcus (GAS) clones closely related by pulsed-field gel electrophoresis (PFGE) and designated as PFGE-1 and PFGE-1.1. These clones, serotyped as M-3, T-3/B3264, carried an allelic variant of the gene that encodes pyrogenic exotoxin A (speA3) and the gene that encodes streptococcal superantigen (SSA) but different emm alleles that encode M-protein. The characteristics and clinical features of patients were similar to those described in previous reports, regardless of the responsible GAS clone. However, worse clinical outcomes (shock and death) were more frequent when patients infected with PFGE1/1.1 clones were considered as a group and compared with all other patients as a group. One striking feature in some patients with deep tissue infection was a lack of inflammatory cells despite the presence of numerous streptococci. An evaluation of PFGE profiles of GAS isolated elsewhere demonstrated that the PFGE-1 clone has caused invasive disease in other locations in the United States and in Japan.

Adult↗
PubMed1998

DNA sequence resembling vanA and vanB in the vancomycin-resistant biopesticide Bacillus popilliae.

The origin of high-level vancomycin resistance in enterococci is unknown. Biopesticidal powders containing spores of Bacillus popilliae, which is vancomycin-resistant, have been used for >50 years in the United States for suppression of Japanese beetle populations. Using a polymerase chain reaction assay designed to amplify the vanB gene in enterococci, an amplicon in B. popilliae was identified and sequenced. The putative ligase gene in B. popilliae had 76.8% and 68.4%-68.9% nucleotide identity to the sequences of the vanA and vanB genes, respectively. There was 75.3% and 69.3%-69.9% identity between the translation of the putative ligase gene in B. popilliae and the translation of the vanA and vanB genes, respectively. We have identified a gene resembling vanA and vanB in B. popilliae. The gene in B. popilliae may have been a precursor to or have had an ancestral gene in common with vancomycin resistance genes in enterococci.

Amino Acid Sequence↗