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Biomedical subjects

L M Dunkle

Publications and source records attributed to L M Dunkle.

At least 37 records · Page 2Linked to original sources
PubMed1988

Changing presentation of herpes simplex virus infection in neonates.

We compared the clinical presentation of 95 newborns with herpes simplex virus (HSV) infection from 1973 through 1981 (first period) with data from 196 newborns evaluated from 1982 through 1987 (second period). There was a significant change in the presentation of infection in these infants. From the first to the second period, the frequency of disseminated disease decreased from 50.5% to 22.9%, whereas the frequency of skin, eye, and mouth (SEM) diseases increased from 17.9% to 43.4% (P less than .001). The frequency of infants with central nervous system (CNS) disease remained relatively unchanged--31.6% versus 33.7%. We also compared the demographic and clinical characteristics of the infants and their mothers. For neonates with CNS or disseminated infection, disease duration and frequency of prematurity were significantly decreased in the second period, as was the frequency of skin vesicles for newborns with SEM or disseminated infection. These changes are most likely the consequence of recognizing and treating SEM infection before its progression to more-severe disease.

Central Nervous System↗
PubMed1987

Septic arthritis in childhood. A 13-year review.

Medical records of 111 children discharged with the diagnosis of septic arthritis from 1973 through 1985 were examined; 122 infected joints were identified. Bacteria were isolated from joint fluid of 75 patients and from blood, cerebrospinal fluid, cervix, bone, or wounds of 16. No agent was isolated from 20 patients, of whom eight had been pretreated with antibiotics. The knee and hip were most often affected overall (73/122), although the ankle was as frequently involved with Haemophilus influenzae type b (6/20). Eighty patients' condition resolved with no sequelae; 18 were unavailable for follow-up. Of the 13 patients with permanent sequelae, ten had had hip joint infections. Although Staphylococcus aureus was isolated from patients of all ages, H influenzae type b was the most frequent pathogen in children 6 through 59 months of age.

Adolescent↗
PubMed1987

Correlation of cerebrospinal fluid endotoxinlike activity with clinical and laboratory variables in gram-negative bacterial meningitis in children.

Detection of endotoxinlike activity in cerebrospinal fluid by Limulus amebocyte lysate gelation has been suggested as a useful technique for the diagnosis of gram-negative bacterial meningitis. We prospectively screened 1,503 cerebrospinal fluid specimens with a Limulus amebocyte lysate microassay. The limit of sensitivity of the assay was 0.01 ng/ml. All specimens that were positive for endotoxinlike activity were subjected to confirmatory retesting, after which 38 (86%) remained positive. Comparison with available culture results revealed that 33 of 38 specimens (86%) were culture positive; 3 of the 5 culture-negative specimens were from patients on therapy for gram-negative bacterial meningitis, and 1 was from a neonate. The overall specificity of confirmed positive tests was 99.5%, with a positive predictive value of 97.3%. There was one false-negative specimen, giving an overall sensitivity of 97.3% and a negative predictive value of 99.9%. Endotoxinlike activities of greater than or equal to 150 ng/ml correlated with present illness of less than 2 days' duration (P = 0.024), elevated cerebrospinal fluid protein (P less than 0.05), and seizures (P = 0.004); levels of greater than or equal to 3,000 ng/ml correlated with neutropenia (P = 0.032), and levels of greater than or equal to 3.2 X 10(6) ng/ml correlated with death (P = 0.001). We conclude that the Limulus amebocyte lysate microslide gelation test has prognostic value as a sensitive, specific, simple, inexpensive screening test for gram-negative bacterial meningitis.

Bacterial Infections↗
PubMed1986

Transformation of a plasmid encoding an adhesin of Staphylococcus aureus into a nonadherent staphylococcal strain.

Plasmid DNA was isolated and purified from a strain of Staphylococcus aureus demonstrating adherence to human epithelial cells, as determined by an assay quantitating adherence of radiolabeled S. aureus to HeLa cells in tissue culture. Other phenotypic characteristics of the donor strain are resistance to ampicillin and absence of hemolysis. A 23.5-kb (kilobase) plasmid was transformed into a nonadherent, ampicillin-sensitive, beta-hemolytic recipient of S. aureus, rendering it both ampicillin-resistant and adherent to a degree approaching that of the donor strain. Plasmid analysis of the donor and transformant strains revealed three identical EcoRI fragments of 7.6 kb, 6.5 kb, and 2.2 kb, together with a 3.6-kb EcoRI fragment in the transformant that demonstrated homology with the last 7.2-kb fragment in the donor. We conclude that an adhesin of S. aureus is encoded by this 23.5-kb penicillinase-encoding plasmid and that techniques of molecular genetics may be utilized to clarify the mechanisms of adherence of S. aureus.

Adhesins, Bacterial↗
PubMed1984

Rapid microprocedure for extraction of plasmid DNA from Staphylococcus aureus.

A rapid micromethod for extraction of plasmid DNA from Staphylococcus aureus in quantities sufficient for restriction endonuclease analysis was developed. The method of "fingerprinting" is useful for identification of epidemic strains in the clinical setting and is more reliable than frequently used determinations of plasmid molecular weight, particularly when small numbers of plasmids are involved.

DNA Restriction Enzymes↗
PubMed1983

pH-dependent oxacillin tolerance of Staphylococcus aureus.

A proportion of clinical isolates of Staphylococcus aureus exhibit resistance to bactericidal activity of certain antibiotics, despite normal susceptibility to inhibition. This phenomenon is termed "tolerance." The methodology used to determine tolerance varies greatly. To clarify the relationship between laboratory methodology and tolerance, we determined the minimal bactericidal concentrations and minimal inhibitory concentrations for 20 clinical isolates by two methods. Inocula were prepared by either 3-h growth of the organism in Mueller-Hinton broth or overnight (22 to 24 h) cultures in Trypticase soy broth (BBL Microbiology Systems, Cockeysville, Md.). All inocula were plated for colony counts and tested for pH. An American Type Culture Collection (Rockville, Md.) reference strain was included in all tests for standardization. Tolerance was defined by the strictest criterion, i.e., a minimal bactericidal concentration/minimal inhibitory concentration ratio of greater than or equal to 100. With the first method, none of the 20 isolates displayed tolerance (mean inoculum pH, 7.15). When inocula were grown in Trypticase soy broth with overnight incubation, 35% (7 of 20) showed tolerance (mean inoculum pH, 6.22). There was a significant association between the decreased bactericidal capacity at high oxacillin concentrations and overnight incubation in Trypticase soy broth (P less than 0.01). We suggest that tolerance in staphylococci is in some way related to the pH value of the inoculating culture. Such pH-induced tolerance may have a clinical corollary in sequestered infections where the pH is acidic.

Hydrogen-Ion Concentration↗
PubMed1983

Age-specific presentation of Campylobacter enteritis in children.

The presentation of Campylobacter enteritis varies with the age of the patient. Abdominal distention is common in infants less than 3 months of age. Fever remains uncommon up to 6 months of age, whereas abdominal pain and fever are common in children more than 1 year of age.

Adolescent↗
PubMed1983

Significance of neutrophils in cerebrospinal fluid samples processed by cytocentrifugation.

We reviewed medical records of 155 pediatric patients whose cerebrospinal fluid (CSF) samples contained an increased proportion of neutrophils when processed by cytocentrifugation, despite normal CSF total white blood cell count. It was determined that these CSF findings occurred more commonly in patients with bacteremia, peripheral leukocytosis, and increased numbers of red blood cells in the CSF. Pulmonary infiltrates in infants and otitis media in children were also significantly associated. Cytocentrifugation allows the identification of neutrophils in the CSF, even in the absence of central nervous system infection. Infants and children with more than 10 per cent neutrophils in CSF require evaluations for focal and bacteremic infections.

Adolescent↗
PubMed1982

Long-term follow-up of ambulatory management of osteomyelitis.

Over four years, 50 patients with osteomyelitis (32 classified as acute and 18 as subacute or chronic disease) were treated with oral antibiotics in an ambulatory setting. The profile of clinical and laboratory parameters, including etiologic agents, was similar to previous series. Forty-eight patients initially received parenteral drugs, mean duration 14 days (range 0-36). Oral agents administered at home included cephalosporins, clindamycin, dicloxacillin, penicillin VK, amoxicillin, and sulfa-trimethoprim. Mean duration of total therapy was 53.2 days (range 16-365). In follow-up, ranging from 12 to 60 months (mean 35), relapses occurred in one patient with acute and one with chronic disease. Both responded to oral treatment. No residual infection has resulted, although clinical and radiographic sequelae remain in six more patients initially termed subacute or chronic. Long-term follow-up of patients receiving high-dose oral antibiotic therapy for osteomyelitis due to sensitive organisms confirms the safety and efficacy of this mode of treatment and the feasibility of ambulatory management. The outcome after oral therapy is equivalent to that following parenteral therapy. Patients with subacute or chronic disease have a significantly poorer prognosis despite a milder initial illness and longer course of therapy.

Administration, Oral↗
PubMed1981

Auditory evoked potentials in bacterial meningitis.

Auditory evoked potentials obtained on infants and children recovering from bacterial meningitis are effective in early and reliable detection of sensorineural deafness, particularly in those who demonstrate absence of wave I.

Child, Preschool↗
PubMed1981

Eradication of epidemic methicillin-gentamicin-resistant staphylococcus aureus in an intensive care nursery.

A methicillin-resistant strain of Staphylococcus aureus (phage type 47,54,75,83A) became epidemic in our 50 bed level III nursery, with a colonization rate of 70 percent and an infection rate of more than 25 percent. This prevalence and the appearance of gentamicin resistance necessitated epidemic control measures. Standard measures included separate housing for infants in whom colonization had occurred and infants in whom it had not, low nurse to patient ratios, and cohorting of all personnel. Use of all antibiotics was curtailed by the requirement of infectious disease consultation. Gentamicin was available only on order of the Director. The colonization rate fell from 55 percent to 25.4 percent, the first-week colonization rate from 31 percent to 0 percent, and the infection rate from 29.3 percent to 15.9 percent over eight weeks. The mean duration of antibiotic therapy decreased from 12.21 to 9.05 days per treated patient; however, the frequency of gentamicin usage and the proportion of gentamicin resistance were unchanged. Nurse to patient ratios were modified to allow increased admissions, but cohorting was continued for 12 weeks until all infants in whom colonization had occurred were discharged. With the elimination of the reservoir, no further colonization occurred and antibiotic resistance did not reappear. Standard infection control measures can eliminate epidemics of multiple antibiotic-resistant Staph. aureus, and control of antibiotic usage may present re-emergence of resistant strains.

Communicable Disease Control↗
PubMed1979

Antibiotic usage in a pediatric medical center.

Antibiotic usage in a large pediatric teaching hospital was evaluated during a three-month period. A total of 1,067 patients received antibiotics and 295 patient records were reviewed. One hundred sixty-nine courses of antibiotics were administered to surgical patients, 77% for surgical prophylaxis. One hundred forty-seven antibiotic courses administered to medical patients were therapeutic in 61.2% and in 35.3% were given because of suspicion of infection. Ampicillin was the most commonly used antibiotic; cephalosporins were used for surgical prophylaxis. Aminoglycosides were used commonly for suspected infection in medical patients. Antibiotic management was inappropriate in 66% of surgical patients and in 21% of medical patients. Not obtaining appropriate studies prior to and during therapy were common infractions on all services. Surgical prophylaxis was freqently inappropriate by reason of no indication, wrong drug or dose, or inappropriate timing.

Adolescent↗