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Biomedical subjects

D A Goldmann

Publications and source records attributed to D A Goldmann.

At least 127 records · Page 7Linked to original sources
PubMed1979

Effect of ampicillin and chloramphenicol alone and in combination on ampicillin-susceptible and -resistant Haemophilus influenzae type B.

To evaluate ampicillin (Amp) and chloramphenicol (Cm) alone and in combination against Haemophilus influenzae type b, we examined the viability of 5 log(10) colony-forming units (CFU) of early-log-phase organisms per ml after 4 and 8 h of incubation with the drug(s). Nine Amp-susceptible (Amp(s)) and five Amp-resistant (Amp(r)) systemic isolates were examined. Antibiotic concentrations included: the minimum inhibitory concentration (MIC) of Amp, 50% of the MIC of Amp, 25% of the MIC of Amp, the MIC of Cm, 50% of the MIC of Cm, 25% of the MIC of Cm, and nine combinations of these concentrations. Both Amp and Cm at their MIC significantly reduced bacterial titers of Amp(s)H. influenzae type b after 8 h of incubation (1.36 and 1.47 log(10) CFU/ml, respectively; both p < 0.01); only Cm at its MIC significantly reduced the number of viable organisms after 4 h (0.91 log(10) CFU/ml; P < 0.001). With Amp(r) organisms, significant reductions in mean bacterial titers occurred after 4 and 8 h of incubation in the presence of Amp at its MIC (1.66 and 2.06 log(10) CFU/ml, respectively; both P < 0.02); smaller but significant reductions were noted after 4 and 8 with Cm at its MIC (0.56 and 0.87 log(20) CFU/ml, respectively; both P < 0.025). Antagonism with Amp(s) or Amp(r) strains was not seen. We conclude that combinations of Amp and Cm have indifferent effects on Amp(s) and Amp(r)H. influenzae type b.

Ampicillin↗
PubMed1979

Evaluation of blood culture procedures in a pediatric hospital.

To determine optimal clinical laboratory techniques for detecting pediatric bacteremia, we studied 7,768 consecutive blood cultures in a 1-year period. Blood was inoculated into one vented 50-ml bottle of brucella broth with 0.05% sodium polyanetholsulfonate and one unvented 50-ml bottle of Columbia broth with 0.05% sodium polyanetholsulfonate and 0.05% cysteine. Bottles were visually examined for growth on days 1 through 7 and blindly subcultured aerobically and anaerobically on days 1, 2, and 7. There were 724 (9.3%) positive cultures, and 484 (6.2%) were clinically significant. The most frequent isolates from bacteremic patients were Haemophilus influenzae (24%) and Streptococcus pneumoniae (17%). Growth was noted in only one bottle in 25% of clinically significant isolates. Bottles inoculated with greater than or equal to 1 ml of blood became positive earlier than bottles inoculated with less than 1 ml. After 1 day of incubation, 48% of the clinically significant cultures showed growth on visual examination, whereas 85% showed growth on subculture. Only 19% of Haemophilus isolates were detected visually on day 1, whereas 88% were recovered on subculture. By day 7, 3.5% of all isolates (including 18% of pneumococcal isolates and 1% of Haemophilus isolates) could no longer be recovered on subculture. We conclude that a two-bottle blood culture system and blind subculture within 24 h will optimize detection of pediatric bacteremia.

Bacteria↗
PubMed1979

Comparative study of erythromycin, amoxicillin and ampicillin antimicrobial activity against human respiratory tract pathogens.

An in vitro test system was used to compare the antimicrobial activity of erythromycin, amoxicillin and ampicillin against respiratory tract pathogens isolated from man. The minimum inhibitory concentrations (MICs) of fresh clinical isolates of Streptoccus pyogenes, Streptocuccus pneumoniae, Staphylococcus aureus and Haemophilus influenzae to the macrolide and penicillins ranged between 0.01 and 0.9 microgram/ml. The microbes were exposed to each antibiotic for approximately 3 h at 1x,2x and 5x the relevant MIC. Irreversible surface defects and intracellular lesions were resolved by scanning and transmission electron microscopy in all antibiotic-treated bacterial species, irrespective of the antimicrobial used. In each case, inhibition of growth was recorded by turbometric assay; no significant difference was observed among the declining slopes of post-dosing growth curves for either erythromycin-, amoxicillin- or ampicillin-treated pathogens. The experimental observations show that the onset of antimicrobial activity and the bactericidal effectiveness of equipotent concentrations of erythromycin, amoxicillin and ampicillin were comparable in this study. The results complement previous clinical, bacteriologic and ultrastructure studies in vivo and demonstrate the contribution of the combined in vivo/in vitro study design for better understanding of antimicrobial activity in human respiratory tract infections.

Amoxicillin↗
PubMed1978

Bacterial colonization of neonates admitted to an intensive care environment.

In order to elucidate some of the factors responsible for the high rate of nosocomial infection associated with neonatal intensive care, we studied bacterial colonization in 63 infants admitted to a neonatal intensive care unit. In a six-month period, cultures of nose, throat, umbilicus, and stool were obtained on admission and every three days from all infants staying in the NICU greater than or equal to 3 days. Study infants did not develop "normal" aerobic flora. Forty-eight percent of infants grew Escherichia coli from stool, but 52% had stool colonization with Klebsiella, Enterobacter, or Citrobacter, the only other Enterobacteriaceae encountered. KEC were also isolated from throat, nose, and umbilicus in 22%, 22%, and 24% of patients, respectively. The risk of stool colonization with KEC increased with duration of hospitalization: 2% of infants were colonized on admission, 60% after 15 days, and 91% after 30 days. Stool colonization with E. coli seemed to protect infants from colonization with other gram-negative bacilli. Thirteen of 20 infants, however, developed pharyngeal GNB colonization in spite of pre-existing abundant growth of alpha streptococci. Antibiotic therapy for greater than 3 days was associated with the isolation of KEC in stool and GNB in the throat, but birth weight less than 2,500 gm and lack of breast milk feedings were not.

Boston↗
PubMed1978

The role of nationwide nosocomial infection surveillance in detecting epidemic bacteremia due to contaminated intravenous fluids.

Since January, 1970, the Center for Disease Control (CDC) has corridnated surveillance of nosocomial infections in a group of voluntarily cooperating hispitals in the United States. In 1970, this surveillance system failed to realize one of its major goals: detection of a nationwide epidemic of septicemia caused by contaminated intravenous products. However, retrospective review of infections reported to CDC revealed that the data received were sufficient for the outbreak to have been recognized. Beginning in July, 1970, one month after the contaminated products were first distributed and five months before the outbreak was actually detected. CDC data showed a persistent increase in the incidence of Enterobacter and Erwinia (presently designated Enterobacter agglomerans) bacteremia. Furthermore, monthly rates of cases of bacteremia caused by these organisms were higher in hospitals using the contaminated intravenous products than for hospitals not using them. Failure to detect this outbreak at the time of its occurrence was due to delays in data processing and insufficiently sophisticated data analysis. Based on this experience, CDC has modified the surveillance system to aid recognition of future outbreaks.

Cross Infection↗
PubMed1977

Correlation of netilmicin agar dilution and disk diffusion susceptibilities.

A study of 283 isolates of gram-negative bacilli revealed a good correlation (r = -0.74) between disk diffusion zones of inhibition and agar dilution minimal inhibitory concentrations. Regression analysis suggested that strains with zone sizes =/<11 mm should be considered resistant, but 34 of 45 strains resistant by minimal inhibitory concentration (including 27 strains of Pseudomonas aeruginosa) would have been called susceptible using this break point.

Anti-Bacterial Agents↗
PubMed1977

Cephalothin prophylaxis in cardiac valve surgery. A prospective, double-blind comparison of two-day and six-day regimens.

A prospective, double-blind study comparing a 6 day with a 2 day regimen of cephalothin prophylaxis was conducted among 200 patients undergoing prosthetic valve replacement. No cases of endocarditis occurred during the 2 month follow-up. Sternal wound infection developed in 2.8 per cent of the 6 day group and 2.1 per cent of the 2 day group. Pneumonia developed in 8.5 per cent of the 6 day and 5.3 per cent of the 2 day group; most of the bacteria isolated were susceptible to cephalothin. Urinary tract infection developed more frequently in the 2 day group (17.0 versus 8.5 per cent), particularly during the first 6 postoperative days. Three of 11 patients with no detectable cephalothin in their sera at the close of operation developed staphylococcal wound infections, compared with 2 of 175 patients whose sera contained cephalothin at the close of surgery (p = 0.002, Fisher's exact test). A short course of prophylactic antibiotics is prudent, but there is no justification for prolonging their administration.

Cephalothin↗
PubMed1976

False-positive blood cultures. Association with nonsterile blood collection tubes.

A substantial increase in blood cultures positive for a Serratia marcescens strain unusually sensitive to antibiotics was noted in two large hospitals within six months. Because the patients' illnesses seemed incompatible with Serratia bacteremia, contamination of blood cultures was suspected. Investigation suggested that pediatric-sized vacuum tubes containing ethylenediamine tetraacetic acid (EDTA) were the source of the organisms, and the epidemic strain of Serratia was recovered from 41 (35%) of the 116 tubes cultured. Mock trials showed that reflux from tube to syringe can occur while vacuum tubes are being filled. Because contaminated EDTA tubes were sometimes inoculated before blood culture bottles in these hospitals, cross-contamination occurred. Most evacuated specimen tubes are not guaranteed sterile by the manufacturer. False-positive blood cultures stemming from the use of nonsterile tubes can be eliminated by inoculating blood culture bottles before other specimen tubes. Because false-positive blood cultures may lead to unnecessary antibiotic therapy, health-care workers should guard against the potential hazard associated with use of these tubes.

Blood↗
PubMedDate not supplied

Methodologic issues in hospital epidemiology. IV. Risk ratios, confounding, effect modification, and the analysis of multiple variables.

Most information in hospital epidemiology comes from observational studies of hospitalized patients, not from planned experiments. Data from observational studies have frequently been used to investigate the effect of exposure to a single factor as a cause or determinant of a discrete outcome, such as infection or death. In such observational studies, the characteristics of study patients may vary widely even within a single hospital. In these investigations, extraneous variables such as differing severity of underlying illness, acting in concert with the exposure variable being studied, may distort the apparent effect of the exposure on the outcome through confounding or may modify the effect of the exposure on the outcome without distorting the relation between them. The data from six published studies are reanalyzed through the use of stratification by severity of underlying illness in order to demonstrate the impact of confounding and effect modification by a third, extraneous variable. Simple methods for dealing with confounding and effect modification in data from hospital epidemiology are presented.

Analysis of Variance↗