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Biomedical subjects

C G Mayhall

Publications and source records attributed to C G Mayhall.

At least 55 records · Page 3Linked to original sources
PubMed1983

Microbial growth patterns in intravenous fat emulsions.

Microbial growth patterns were studied in intravenous fat emulsions under conditions that simulated touch contamination before or during administration. Commercially available emulsions of 10% and 20% soybean oil and 10% safflower oil in 500-ml bottles were inoculated with two concentrations of each of four organisms: a coagulase-negative Staphylococcus isolated from a venipuncture site, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. The bottles were kept at room temperature, and samples were taken by direct puncture of the i.v. port at 0, 3, 6, 12, 24, 48, and 72 hours, diluted, and plated. Emulsions were visually inspected daily. Growth of the coagulase-negative Staphylococcus was minimal for 48 hours. E. coli showed substantial growth within 12 hours in all three emulsions. Growth patterns for Ps. aeruginosa were similar in all emulsions, and growth approximated that of E. coli within 48 hours. The growth rate of C. albicans was intermediate between that of Staphylococcus and those of E. coli and Ps. aeruginosa. Growth of C. albicans was greater in 10% safflower oil emulsion than in the other emulsions. No physical changes were observed. The coagulase-negative Staphylococcus showed less growth than C. albicans, Ps. aeruginosa, and E. coli. Substantial growth within 12 hours was seen only with E. coli. C. albicans exhibited preferential growth in 10% safflower oil emulsion.

Bacteria↗
PubMed1981

Aminoglycoside predictions using a hand-held calculator: limitations of the model.

Previously published methods for determining an appropriate aminoglycoside dosage have been adapted for use in the hand-held programmable calculator (Texas Instrument-59). The purpose of this study was to evaluate the accuracy of calculator-generated serum level predictions compared with measured values. Twenty-four adult patients receiving intravenous aminoglycosides (gentamicin, netilmicin, or tobramycin) had urine and serum collected for creatinine clearance calculations and had blood obtained for peak and through aminoglycoside concentration determinations. All but one patient had normal renal function. A statistically significant relationship between predicated and measured creatinine clearance values was found. There was also generally good agreement between the calculator-predicted aminoglycoside levels and the measured levels, although some patients exhibited unexplained deviations. Error in the estimation of creatinine clearance and adjustments for lean body weight did not improve prediction accuracy. We conclude that the hand-held calculator was able to predict measured aminoglycoside levels for most patients with acceptable precision. However, the calculator method offers no real advantage over other methods (except speed in performing the calculation), and may give the user a false sense of security.

Aminoglycosides↗
PubMed1981

Evaluation of a device for monitoring sterility of injectable fluids.

An evaluation of a sterility-testing device (Addi-Chek) that uses total-sample membrane filtration is presented. Parenteral nutrition solutions were deliberately contaminated at low levels with 16 bacterial and four fungal strains. Some contaminated solutions were stored at 20 degrees C or 4 degrees C for up to 24 hours before testing; the rest were tested immediately. Additionally, one liter of pharmacy-prepared infusion fluid was tested each day for 100 days. Broth (added to the Addi-Chek unit after filtration to permit microbial growth) was cultured when it became turbid or after a 10-day incubation. Fifty-nine deliberate-inoculation tests were done. The organism was recovered from 56 of these; the other three tests may have been negative because no organisms were present in the aliquot used for inoculation or because of experimental error. The number of organisms used for inoculation varied from 1 to 80; 86% of the tests used 25 organisms or less. Storage for up to 24 hours at 20 degrees C and 4 degrees C had no effect on the results of sterility testing. In testing 100 units of pharmacy-prepared fluid (not deliberately contaminated), one unit (1%) was found to be contaminated. Pharmacy personnel correctly identified positive and negative Addi-Chek units based on visual turbidity of the broth. It is concluded that Addi-Chek is easy to use and effective in detecting low-level contamination in intravenous fluids.

Drug Combinations↗
PubMed1980

Sequential outbreaks of infection due to Klebsiella pneumoniae in a neonatal intensive care unit: implication of a conjugative R plasmid.

Sequential outbreaks of infection in a neonatal intensive care unit were due to multiple antibiotic-resistant strains of Klebsiella pneumoniae of different serotypes. In investigations of these outbreaks, the transfer of resistance to gentamicin, ampicillin, cephalothin, carbenicillin, and kanamycin from gentamicin-resistant organisms to standard laboratory recipients and between recipients was observed. Purified plasmid DNA, isolated from all multiple antibiotic-resistant strains, was analyzed by agarose gel electrophoresis, which revealed a common, large plasmid component with a molecular size of 71 megadaltons. Analysis of drug-resistant progeny suggested this plasmid encoded resistance to antibiotics and the information needed for its transmission. The identity of the plasmid from three different sources was established by the use of restriction-enzyme fingerprinting. The dissemination and persistence of this plasmid in environmental and fecal organisms, despite the disappearance of multiple antibiotic-resistant K. pneumoniae, provided a potential source for spread to other bacteria.

DNA↗
PubMed1980

Effect of storage and changes in bacterial growth phase and antibiotic concentrations on antimicrobial tolerance in Staphylococcus aureus.

Forty clinical isolates of Staphylococcus aureus were tested for tolerance to oxacillin and cephalothin by broth dilution susceptibility tests and killing curves. Most experiments were carried out with stationary-phase inocula, but nine tolerant isolates were retested with log-phase inocula. All 40 isolates were retested in killing curves at double the antibiotic concentrations used in initial tests. Isolates were retested for tolerance to oxacillin after storage at --70 degrees C for 1 year. In broth dilution tests, 23 of 40 (57.5%) and 20 of 40 (50%) isolates were tolerant to oxacillin and cephalothin, respectively. By killing curves, 25 of 40 (62.5%) and 22 of 40 (55%) isolates were tolerant to oxacillin and cephalothin, respectively. When nine tolerant isolates were retested with log-phase inocula, none manifested tolerance. Only 25 to 30% of the isolates were tolerant in killing curves performed with oxacillin and cephalothin at concentrations double those used in initial tests. After storage at --70 degrees C for 1 year, only two-thirds of the isolates remained tolerant. In isolates that remained tolerant, the degree of tolerance diminished to about 25% of that observed in initial tests.

Anti-Bacterial Agents↗
PubMed1979

Enterobacter cloacae septicemia in a burn center: epidemiology and control of an outbreak.

An outbreak of infections due to Enterobacter cloacae occurred in the burn center at the Medical College of Virginia (Richmond, Virginia) in 1976. Fifteen patients had bacteremia due to E. cloacae; 10 cases of bacteremia occurred during a six-week period in January and February. The development of bacteremia was significantly related to the extent of third-degree burn and to admission to the burn center in January and February but not to the presence of an intravenous cannula, underlying disease, or antimicrobial therapy. E. cloacae was spread by contaminated hands of personnel and by cross-contamination of hydrotherapy water. A shortage of staff appeared to be an important factor in the occurrence of the outbreak. Control measures included an increase in the number of personnel, instruction of personnel in proper aseptic technique, and adoption of a new hydrotherapy protocol.

Adolescent↗
PubMed1979

Viral hepatitis: prevention and prophylaxis.

Hepatitis A is spread by fecal-oral transmission and accounts for 25% of the cases of sporadic hepatitis in this country; fatal cases have been documented but are unusual, and chronic hepatitis A has not been documented. Hepatitis B is spread by varied routes of transmission, fecal-oral being the least important, and accounts for half the cases of sporadic hepatitis in this country; fatal cases are well documented and chronic hepatitis B is common. The only documented route of transmission of non-A, non-B hepatitis is parenteral; fatal and chronic cases have been documented, and a quarter of the cases of sporadic hepatitis are non-A, non-B. Diagnosis of the etiology of viral hepatitis cannot be determined on clinical grounds but must be made through serologic tests.

Adult↗
PubMed1978

Resistant Enterobacter cloacae in a burn center: the ineffectiveness of silver sulfadiazine.

Enterobacter cloacae sepsis was found in 15 burn center patients in 1976, of whom 13 died. Nine of the deaths occurred in the first 60 days. The Burn Center isolates were resistant to silver sulfadiazine (AgSD) in agar cup-plate tests and confirmed by tube dilution tests. Hospital, non-burn isolates of E. cloacae were sensitive to AgSD. All E. cloacae isolates were sensitive to mafenide acetate (MA) in the agar cup-plate tests, but this was not confirmed by the tube dilution tests. The agar cup-plate susceptibility test is a simple, rapid and effective technique for determining resistant and sensitive isolates of E. cloacae. Patients who were changed from AgSD to MA because of resistant E. cloacae infection did not have improved survival. An animal study showed that AgSD was ineffective against this strain of E. cloacae and that MA was more effective than AgSD when applied 24 hr postburn but neither were effective at 48 hr postburn. MA was bacteriostatic but not bactericidal with this E. cloacae strain.

Animals↗
PubMed1978

Incidence and characteristics of antibiotic-tolerant strains of Staphylococcus aureus.

Thirty clinical isolates of Staphylococcus aureus were tested for tolerance to oxacillin, cephalothin, and gentamicin by using killing curves and broth dilution susceptibility tests. Tolerance was defined as the presence of>/=100 colony-forming units per ml remaining after 24 h of incubation of the killing curve suspensions. Nineteen of 30 isolates were tolerant to oxacillin and cephalothin, but none was tolerant to gentamicin. Among the tolerant isolates, there was a wide spectrum of tolerance, with from 0.2 to 43% of the colony-forming units in the starting inoculum remaining after 18 to 24 h of incubation. Tolerance was unrelated to phage type or to any of several other characteristics studied.

Anti-Bacterial Agents↗
PubMed1977

In vitro activity of five oral cephalosporins against anaerobic pathogenic bacteria.

The in vitro inhibitory activities of cefaclor and and cefatrizine, two new orally absorbed cephalosporin antibiotics, against 44 isolates of anaerobic pathogenic bacteria were measured using the agar dilution procedure of the World Health Organization-International Collaborative Study. Tests also were performed with cephalexin, cephaloglycin, and cephadrine, as well as with the parenteral cephamycin antibiotic cefoxitin. Cefoxitin was the most active antibiotic and inhibited the majority of isolates at a concentration of less than or equal to 4 microgram/ml. None of the oral cephalosporins was clearly superior against all of the anaerobic isolates; only cephadrine and cefatrizine appeared to have any potential clinical value.

Bacteroides↗
PubMed1976

Cutaneous protothecosis. Successful treatment with amphotericin B.

A patient had cutaneous protothecosis because of the alga-like organism, Prototheca wickerhamii. In vitro sensitivity tests showed that the organism was sensitive to amphotericin B, and was treated successfully with this polyene antibiotic. As with treatment of some fungal infections, a clinical response was achieved when therapy with low doses of amphotericin B was given during a short period of time. The basis of the amphotericin B response may have been due to a combination of its immunostimulatory and antibiotic properties.

Adult↗
PubMed1976

Variation in the susceptibility of strains of Staphylococcus aureus to oxacillin, cephalothin, and gentamicin.

Three cases of staphylococcal bacteremia caused by organisms that were inhibited by low concentrations of oxacillin, but were resistant to the killing effects of oxacillin, stimulated us to screen 60 clinical isolates of Staphylococcus aureus for their susceptibility to oxacillin, cephalothin, and gentamicin. All 60 strains were inhibited by low concentrations of the antibiotics. The antibiotics were bactericidal against 27 of the 60 strains and only bacteriostatic against the other 33 after 24 h of incubation. However, after 48 h of incubation, the antibiotics were also bactericidal against the latter group.

Adolescent↗
PubMed1976

Preparation and evaluation of 111In-labeled leukocytes as an abscess imaging agent in dogs.

Leukocytes labeled with 111In chelated with 8-hydroxyquinoline were evaluated as an abscess imaging agent in dogs. The labeling technique is simple and offers 75-95% efficiency. The half-clearance time of the labeled leukocytes is 6-10 hours, and the target-to-blood activity ratios are higher than those of other compounds now in use. The authors suggest that 111In-labeled leukocytes replace 67Ga citrate as a routine abscess imaging agent.

Abscess↗