Papers by David Bamberger
Clinical Infectious Diseases, Sep 1, 1996
Missouri medicine, Jul 1, 2020
Staphylococcus aureus bacteremia (SAB) is a serious cause of bloodstream infection associated wit... more Staphylococcus aureus bacteremia (SAB) is a serious cause of bloodstream infection associated with significant morbidity and mortality. Complications include deep-seated foci of infection including infective endocarditis, device-associated infection, osteoarticular metastases, pleuropulmonary involvement, and recurrent infection. With the 30-day all-cause mortality being around 20%, a collaborative effort of early Infectious Diseases (ID) consultation and Antimicrobial Stewardship Program (ASP) involvement will show improved SAB outcomes and therapy optimization.1.
Antimicrobial Agents and Chemotherapy, Feb 1, 1993
Clinical reports and animal models have demonstrated that cefazolin may have decreased efficacy a... more Clinical reports and animal models have demonstrated that cefazolin may have decreased efficacy against some strains of Staphylococcus aureus because of type A 1-lactamase-mediated hydrolysis. We sought to measure biologically active cefazolin concentrations within abscesses with high concentrations of S. aureus and compare the concentrations with those of cefmetazole, a j3-lactamase-stable cephamycin. A type A 13-lactamaseproducing strain of S. aureus with a demonstrated inoculum effect against cefazolin (MIC at an inoculum of 5 x 10' CFU/ml, 1.0 ,ug/ml; MIC at an inoculum of 5 x 107 CFU/ml, 32.0 ,ug/ml) but not cefmetazole (MICs at inocula of 5 x 105 and 5 x 107 CFU/ml, 2.0 ,g/ml) was used. Cefazolin or cefmetazole (100 mg/kg of body weight every 8 h for 8 days) was administered to rabbits with infected tissue cages. No differences in the concentrations of the two drugs in the uninfected tissue cages were observed. Higher concentrations of cefmetazole than cefazolin were found in infected tissue cages at day 3 (5.9 0.7 versus 2.2 + 0.3 ,ug/ml; P < 0.01), day 5 (9.1 + 2.6 versus 3.6 + 0.7 ,ug/ml; P = 0.02), and day 8 (9.4 + 1.4 versus 4.8 + 0.9 tig/ml; P = 0.01) after infection. Cefazolin and cefmetazole were equally effective in reducing the bacterial concentration in the abscess. In vitro experiments demonstrated greater cefazolin than cefmetazole degradation by S. aureus, but the differences were greater in serum than in abscess fluid supernatants. We conclude that abscess cefazolin concentrations are diminished by type A P-lactamase-producing S. aureus, but this did not affect drug efficacy in this model.
The FASEB Journal, Apr 1, 2009
PubMed, Jun 1, 1988
Nosocomial pneumonia occurs in 0.6% of hospitalized patients. The usual causative agents are gram... more Nosocomial pneumonia occurs in 0.6% of hospitalized patients. The usual causative agents are gram-negative bacilli, Staphylococcus aureus, Streptococcus pneumoniae, and anaerobic bacteria. In immunocompromised hosts, the differential diagnosis also includes fungi, mycobacteria, viruses, Nocardia, and Pneumocystis carinii. Important risk factors for the development of nosocomial pneumonia include prolonged mechanical ventilation, thoracic or upper abdominal surgery, altered mental status, underlying immunosuppression, chronic obstructive pulmonary disease, and the use of antacids or histamine type 2 blockers. Colonization of the oropharynx and tracheal secretions with gram-negative aerobic bacteria is common in hospitalized patients with or without pneumonia. The diagnosis of nosocomial pneumonia is usually based on the clinical features of dyspnea, cough, fever, purulent sputum production, new pulmonary infiltrates, hypoxemia, and leukocytosis. However, the clinician must recognize that the presence of these features is neither sensitive nor specific in the diagnosis of nosocomial pneumonia. Microbiologic diagnosis is also difficult because blood cultures are usually negative, and cultures of tracheal secretions, although usually sensitive, are not specific. Invasive procedures may prove useful, but most have yet to be studied in large groups of patients with nosocomial pneumonia.
Missouri medicine, Jul 1, 2020
Sexually transmitted infections have increased dramatically in the past 10 years. Rates are highe... more Sexually transmitted infections have increased dramatically in the past 10 years. Rates are higher in Missouri than nationally, and higher in the large urban areas, in young adults, racial minority groups, among men having sex with men, and are associated with injection drug and methamphetamine use. Clinicians need to perform an appropriate sexual history and follow guidelines for screening and treatment. There is increasing concern for resistance among gonococcal isolates which limits future treatment options.
Journal of Infection, May 1, 2006
To determine if differences in drug-related Staphylococcus aureus killing, associated in vivo wit... more To determine if differences in drug-related Staphylococcus aureus killing, associated in vivo with neutropenia, is neutrophil-related in vitro, and the mechanisms of this interaction. Methods: To evaluate the influence of living neutrophils on drugS. aureus interactions, cell wall enzymes, the PBPs, were isolated and their binding to five (beta lactam and other) antibiotics was evaluated following incubation (or not) with neutrophils. S. aureus killing by the test drugs was assayed in growth media of sterile filtered abscess fluid, either neutropenic infected or normal infected. At MBCs for the test isolate, each drug or saline control was incubated with S. aureus 10 6 and dilution-plated. Results: Neutrophil incubation with S. aureus eliminated the S. aureus PBP-2 band in all Western blots irrespective of the drug used to tag the PBPs. Time-kill of S. aureus grown in neutropenic or normal abscess fluid showed greater kill by all drugs in neutropenic abscess fluid (pZ0.029 6 h incubation). Killing difference between the media correlates with drug PBP-2 activity. Conclusions: Drug activity against S. aureus in vitro is changed by neutrophil incubation. The neutrophil-induced loss of S. aureus PBP-2 drug binding suggests novel hostbacterial interaction that may impinge on drug treatment of S. aureus infections.
PubMed, Aug 1, 2007
Staphylococcus aureus bacteremia is a common disease with a high risk of mortality and complicati... more Staphylococcus aureus bacteremia is a common disease with a high risk of mortality and complications. An increasing proportion of cases are methicillin-resistant S.aureus (MRSA), and methicillin-resistance is being observed from both community-acquired bacteremias and in healthcare-associated infections. The duration of bacteremia and transesophageal echocardiographic findings are useful in predicting the likelihood of complications including endocarditis. Therapy with vancomycin has been the mainstay in the treatment of MRSA bacteremias, but is associated with a long duration of bacteremia on therapy and relapses. Loss of susceptibility to vancomycin, due to thickened cell walls and through the acquisition of the vanA gene, has been described. Daptomycin is newly approved lipopeptide that is highly bactericidal against most strains of MRSA. In a randomized trial, daptomycin was demonstrated to be effective in the treatment of S. aureus bacteremia and right-sided endocarditis. However treatment failures associated with isolates with daptomycin non-susceptibility are reported, and there is a correlation between isolates with reduced vancomycin susceptibility and reduced daptomycin susceptibility. Daptomycin is a useful alternative to vancomycin in the therapy of MRSA bacteremia and endocarditis. However the appropriate role of daptomycin in optimizing therapy with MRSA bacteremia and endocarditis remains to be elucidated.
PubMed, Oct 1, 1993
Therapy for osteomyelitis requires a multidisciplinary approach. A precise microbiologic diagnosi... more Therapy for osteomyelitis requires a multidisciplinary approach. A precise microbiologic diagnosis and adequate debridement of necrotic tissue are essential. Acute hematogenous osteomyelitis usually responds to antimicrobial therapy. The presence of an abscess or a metaphyseal cavity in hematogenous osteomyelitis and evidence of spinal cord compression in vertebral osteomyelitis require surgical treatment. Chronic osteomyelitis usually implies that dead bone is present, which requires surgical debridement. Because of the chronicity of the infection and various presentations and surgical approaches, antibiotic treatment must be individualized. In general, however, at least 4 weeks of therapy is required.
PubMed, Dec 15, 2010
Although the annual incidence of bacterial meningitis in the United States is declining, it remai... more Although the annual incidence of bacterial meningitis in the United States is declining, it remains a medical emer- gency with a potential for high morbidity and mortality. Clinical signs and symptoms are unreliable in distinguishing bacterial meningitis from the more common forms of aseptic meningitis; therefore, a lumbar puncture with cerebro- spinal fluid analysis is recommended. Empiric antimicrobial therapy based on age and risk factors must be started promptly in patients with bacterial meningitis. Empiric therapy should not be delayed, even if a lumbar puncture cannot be performed because results of a computed tomography scan are pending or because the patient is awaiting transfer. Concomitant therapy with dexamethasone initiated before or at the time of antimicrobial therapy has been demonstrated to improve morbidity and mortality in adults with Streptococcus pneumoniae infection. Within the United States, almost 30 percent of strains of pneumococci, the most common etiologic agent of bacterial meningitis, are not susceptible to penicillin. Among adults in developed countries, the mortality rate from bacterial meningitis is 21 percent. However, the use of conjugate vaccines has reduced the incidence of bacterial meningitis in children and adults.
Sexually Transmitted Diseases, May 1, 2019
Background: Current guidelines recommend screening for extragenital gonorrhea (GC) and chlamydia ... more Background: Current guidelines recommend screening for extragenital gonorrhea (GC) and chlamydia (CT) only among men having sex with men (MSM). Extragenital GC and CT is associated with treatment failure and disease transmission. The prevalence of extragenital GC/CT infections in women and in men having sex with women (MSW) are less well studied. We sought to determine the prevalence of extragenital CG and CT among all persons attending a sexually transmitted diseases clinic who engaged in extragenital sexual activity. Methods: We examined demographic and clinical data of all patients who engaged in extragenital sexual activity between January 2012 and October 2014. Nucleic acid amplification testing for GC and CT was performed at sites of exposure among all men and women at pharyngeal, rectal, and urogenital sites. Multivariable logistic regression analyses were performed to determine the extent that age, race/ethnicity, and number of sexual partners predicted a positive test result. Results: Pharyngeal GC was found in 3.1% of MSW, representing 35% of the GC infections in MSW. Thirty-six percent of MSW with pharyngeal GC tested negative at their urogenital site. Pharyngeal GC in MSW prevalence was higher among those with younger age or a higher number of sex partners. Pharyngeal GC, rectal GC, and rectal CT rates were 8.5%, 15.0%, and 16.5%, respectively, among MSM and 3.8%, 4.8%, and 11.8% among women having sex with men (WSM), respectively. Conclusions: Extragenital GC and CT rates of infection was highest among MSM but was also observed in WSM and MSW, representing an unrecognized disease burden.
PubMed, Dec 15, 2005
Because of high incidence, morbidity, and antimicrobial resistance, Staphylococcus aureus infecti... more Because of high incidence, morbidity, and antimicrobial resistance, Staphylococcus aureus infections are a growing concern for family physicians. Strains of S. aureus that are resistant to vancomycin are now recognized. Increasing incidence of unrecognized community-acquired methicillin-resistant S. aureus infections pose a high risk for morbidity and mortality. Although the incidence of complex S. aureus infections is rising, new antimicrobial agents, including daptomycin and linezolid, are available as treatment. S. aureus is a common pathogen in skin, soft-tissue, catheter-related, bone, joint, pulmonary, and central nervous system infections. S. aureus bacteremias are particularly problematic because of the high incidence of associated complicated infections, including infective endocarditis. Adherence to precautions recommended by the Centers for Disease Control and Prevention, especially handwashing, is suboptimal.
Mycoses, Sep 3, 2015
The goal of this study was to report on the potential utility of cerebrospinal fluid (CSF) Coccid... more The goal of this study was to report on the potential utility of cerebrospinal fluid (CSF) Coccidioides antigen testing in the diagnosis and management of Coccidioides meningitis. We retrospectively reviewed medical records of seven patients with Coccidioides meningitis who had Coccidioides antigen tests performed on CSF. In two severely immunocompromised patients, CSF Coccidioides antigen testing was helpful in the diagnosis when other testing modalities were negative. Coccidioides antigen testing was also useful in the management of patients who had progression of disease due to non-adherence, development of resistance, failure of therapy and the presence of vasculitis. Changing antigen levels helped identify disease complications in three patients that led to alterations in therapy or management. On the basis of our review of these seven patients with Coccidioides meningitis, we concluded that the Coccidioides antigen test contributed to the diagnosis and management of patients with Coccidioides meningitis.
Archives of internal medicine, Mar 1, 1992
The purpose of this study was to assess and compare the impact of voluntary compliance and enforc... more The purpose of this study was to assess and compare the impact of voluntary compliance and enforced compliance with institutional guidelines for initiating third-generation cephalosporin therapy. An audit of third-generation cephalosporin use during a 6-month period shortly after ceftriaxone and ceftazidime were added to the hospital formulary already containing cefotaxime was performed. During this period, compliance to institutional guidelines for initiating therapy was voluntary. A follow-up audit during a similar 6-month period was performed to assess compliance with institutional guidelines shortly after an enforcement policy was placed in effect. The results of these two audits were compared to assess usage patterns of these cephalosporins, compliance rates with institutional guidelines for initiating therapy, use of susceptibility testing to guide therapy, effect of use of these drugs on susceptibility patterns within the hospital, and third-generation cephalosporin costs during periods when institutional policy was unenforced and enforced. Only 24.2% of 66 courses of third-generation cephalosporins were initiated in compliance with institutional guidelines during the initial audit period. Susceptibility testing revealed an organism susceptible to a first-generation cephalosporin in 13 courses but in only six instances was a switch to the more narrow-spectrum antibiotic performed. At the time routine susceptibility testing to ceftazidime and ceftriaxone was instituted, 92% of Enterobacter cloacae were sensitive to ceftriaxone and 89% of Pseudomonas aeruginosa were sensitive to ceftazidime. Fifteen months later, when voluntary compliance to institutional policy was terminated, 70% of E cloacae were sensitive to ceftriaxone and 73% of P aeruginosa were sensitive to ceftazidime. During the last 6 months of this period, pharmacy expenditures totaled $50,000. The second audit revealed 85.4% of 48 courses of treatment complied with guidelines for initiating therapy. Since enforcement was instituted, sensitivity of E cloacae to ceftriaxone has risen to 88% and sensitivity of P aeruginosa to ceftazidime has increased to 80%. Pharmacy expenditures decreased to $23,000.
Comprehensive Therapy, Jun 1, 2000
The diagnosis and therapy of osteomyelitis remains difficult despite recent advances. Clinical de... more The diagnosis and therapy of osteomyelitis remains difficult despite recent advances. Clinical decision making is also difficult because of considerable variations in the types of disease observed and the lack of large comparative trials studying the variety of approaches.
Journal of Antimicrobial Chemotherapy, 1995
We studied the efficacy and pharmacokinetics of azithromycin in a rabbit tissue-cage Staphylococc... more We studied the efficacy and pharmacokinetics of azithromycin in a rabbit tissue-cage Staphylococcus aureus abscess model. A dosage of 15 mg/kg/day azithromycin was administered to rabbits with 24 h or 2 week old infected tissue cages and to uninfected controls. Concentrations of azithromycin were higher in the infected compared with the uninfected tissue cages. Azithromycin was effective in reducing the bacterial concentrations in both groups of infected tissue cages by approximately 3 log10 cfu/mL compared with untreated controls after 8 days of therapy. Fifty percent of the 24 h and 29% of the 2 week infected tissue cages became culture-negative.
Clinical Infectious Diseases, Apr 1, 1999
The Journal of Infectious Diseases, Oct 1, 1993
Microbial growth and antimicrobial bacterial killing are both diminished in abscesses. It was pos... more Microbial growth and antimicrobial bacterial killing are both diminished in abscesses. It was postulated that zinc depletion in abscesses, perhaps secondary to a neutrophil protein resembling calprotectin, may be partly responsible for these effects. In a rabbit tissue-cage abscess model, pooled abscess supernatant concentration of zinc was &lt; 1.53 microM. The addition of 41.7 microM zinc had no effect on Staphylococcus aureus growth or the bacterial killing effect of cefazolin in serum. In abscess fluid supernatants, bacterial growth without antibiotic and bacterial killing by cefazolin were both enhanced by the addition of zinc. Fractionation of the abscess fluid with ultrafiltration membranes showed that these effects could be reproduced with the fraction between 30 and 50 kDa. These findings suggest that a protein in abscess fluid supernatants that resembles the neutrophil protein calprotectin may, through its zinc binding effects, inhibit microbial growth within an abscess but also inhibit the activity of bactericidal antibiotics.
Annals of Internal Medicine, Sep 1, 1995
To describe the association between fluconazole and reversible alopecia. A retrospective survey o... more To describe the association between fluconazole and reversible alopecia. A retrospective survey of 1) patients enrolled in NIAID Mycoses Study Group (MSG) protocols involving the long-term use of fluconazole for treatment of endemic mycoses and 2) patients treated with fluconazole outside of a protocol setting but by the MSG investigators who were MSG members. 26 MSG sites in the United States. 33 patients with various deep and superficial mycoses who developed alopecia while receiving fluconazole. 11 of 26 investigators reported a total of 33 patients with substantial alopecia related to fluconazole therapy. Underlying mycoses included blastomycosis, sporotrichosis, histoplasmosis, cryptococcosis, coccidioidomycosis, and mucosal candidiasis. In separate MSG studies, 17 of 136 (12.5%) and 8 of 40 (20%) patients had substantial reversible alopecia associated with fluconazole therapy. Eight patients who were not in the protocol had similar adverse effects. Twenty-nine of 33 patients (88%) received at least 400 mg of fluconazole daily for a mean of 7.1 months. Alopecia developed a median of 3 months after initiation of fluconazole therapy and involved the scalp in all patients. Other sites were involved in about one third of patients. Three patients required wigs because of extensive hair loss. Alopecia resolved within 6 months of discontinuation of fluconazole therapy or reduction of the daily dose by at least 50%. Alopecia appears to be a common adverse event associated with higher-dose (400 mg/d) fluconazole given for 2 months or longer. This effect may be severe but is reversed by discontinuing fluconazole therapy or substantially reducing the daily dose.
Journal of Infectious Diseases, 2016
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Papers by David Bamberger