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Biomedical subjects

G D Overturf

Publications and source records attributed to G D Overturf.

89 records · Page 5Linked to original sources
PubMed1975

In vitro evaluation of BL-S640, a new oral cephalosporin antibiotic.

BL-S640, a new oral cephalosporin analogue, was evaluated in vitro against 102 gram-negative and 80 gram-positive bacteria. The antimicrobial spectrum was similar to that of previous cephalosporin analogues. Good antimicrobial activity against strains of Escherichia coli, Klebsiella, staphylococci, and streptococci was demonstrated. Relatively poor activity and/or resistance was noted among most strains of Proteus, Providencia, Pseudomonas, and Serratia. In comparative studies BL-S640 had better activity against strains of Hemophilus influenzae, Staphylococcus aureus, and Enterobacteriaceae than many cephalosporin analogues. Variation of susceptibility results was dependent upon the type of media and inoculum size. Cross-resistance between BL-S640 cephalexin, cephalothin, and cefazolin was demonstrated. Among strains of Klebsiella the more rapid selection of resistance ot other cephalosporins was in contrast to BL-S640. Experience in vitro with BL-S640 has documented its antimicrobial activity,and further studies of pharmacokinetics and therapeutic efficacy are indicated.

Bacteria↗
PubMed1975

Osteomyelitis and sepsis: severe complications of fetal monitoring.

Sophisticated modern methods of fetal monitoring during labor have improved the prognosis for high-risk infants, but the possible adverse side effects have not yet been fully documented. One infant with osteomyelitis and one with streptococcal sepsis are reported. In the future, greater attention should be paid to such potential complications and new noninvasive techniques of fetal monitoring should be developed.

Cellulitis↗
PubMed1974

Rapid, specific microbiological assay for amikacin (BB-K8).

The emergence of a strain of Providencia stuartii resistant to multiple antibiotics with the exception of amikacin provided a test organism for a microbiological assay for this new semisynthetic aminoglycosidic aminocyclitol. Results can be read at 4 h and are specific for amikacin. The resistance of P. stuartii to all currently used antibiotics allows the utilization of this technique in the presence of other concurrently administered antibiotics and therefore eliminates the need for their inactivation in the assay procedure. The rapidity, specificity, and simplicity of this microbiological assay may provide a technique for routine clinical monitoring of patients on therapeutic regimens and could be utilized by institutions unable to perform the radioimmunoassay or radioassay techniques.

Amikacin↗
PubMed1974

Comparative in vitro evaluation of BL-P1654 and carbenicillin against Pseudomonas.

Prior investigators have reported a broad gram-negative spectrum and a marked anti-Pseudomonas activity in vitro with BL-P1654, 6-[R-alpha-(guanylureido)phenylacetamido]-penicillanic acid. An in vitro comparison of BL-P1654 to carbenicillin was performed against 84 strains of Pseudomonas and 39 strains of Enterobacteriaceae. Mean minimal inhibitory concentrations in Mueller-Hinton broth of BL-P1654 and carbenicillin were 12.5 and 100 mug/ml, respectively. Bactericidal studies with representative strains of Pseudomonas showed a consistent lack of bactericidal activity with BL-P1654. Mean bactericidal concentrations of BL-P1654 and carbenicillin were >/=200 and 100 mug/ml, respectively. The lack of bactericidal activity of BL-P1654 was further substantiated with the "killing curve" technique. Based on these data, BL-P1654 can not be considered a substitute for carbenicillin as the penicillin analogue of choice for Pseudomonas infections.

Anti-Bacterial Agents↗
PubMed1974

Phosphorylation of kanamycin, lividomycin A, amd butirosin B by Providencia stuartii.

The isolation of Providencia stuartii resistant to multiple aminoglycoside antibiotics prompted an investigation into the mechanism of their resistance. Crude enzyme extracts of a strain of P. stuartii inactivated kanamycin, lividomycin A, and butirosin B in the presence of adenosine 5'-triphosphate (ATP), as measured by a microbiological assay. The occurrence of inhibitory concentrations of 500 mug or greater per ml against kanamycin, lividomycin A, and butirosin B, coupled with the inactivation of these antibiotics in the presence of ATP, suggested enzymatic phosphorylation. This was documented by the transfer of the gamma-phosphate of [gamma-(32)P]ATP. In contrast, the inability to inactivate gentamicin or tobramycin by the crude enzyme extracts in the presence of ATP suggests another enzymatic mechanism of resistance for these antibiotics, such as adenylation or acetylation. Of importance is the fact that amikacin, a semisynthetic analogue of kanamycin A which is resistant to inactivation by most resistance transfer factor enzymes, was found to inhibit the growth of P. stuartii at low concentrations.

Aminoglycosides↗
PubMed1970

Studies of the relationship between the production of bacteriocines by group A streptococci and acute glomerulonephritis.

The previously reported relationship between nephritogenicity and bacteriocine production among Group A streptococci has been examined. Using techniques comparable to the earlier study, the present study did not reveal any such relationship. Among 73 strains tested, 53% produced bacteriocines; no significant difference was noted between bacteriocines from strains isolated from cases of nephritis and those from a group of strains recovered from patients with other conditions. In addition, no correlation between type and bacteriocine production was observed.

Acute Disease↗
PubMedDate not supplied

Analysing antibody response based on data obtained from serial dilution methods.

We identify several problem areas in statistical analyses of data obtained from serial dilution methods in serology. We provide the mathematical backgrounds of the key elements involved in this field of study and discuss the statistical considerations. The problem areas include the use of the geometric mean as an expression of the average of a set of observations, the use of fold increase to measure antibody response, and the statistical analysis of the change in antibody response with respect to other variables, such as age and pre-titer levels.

Adult↗
PubMedDate not supplied

Role of empiric parenteral antibiotics prior to lumbar puncture in suspected bacterial meningitis: state of the art.

The performance of lumbar puncture (LP) in patients with suspected meningitis is often delayed if, for example, the clinical presentation suggests a need for prior computed tomographic (CT) scan or if patients are initially examined at settings with limited clinical facilities. The role of empiric parenteral antibiotic therapy prior to LP under these circumstances has not been critically analyzed. Review of the literature suggests that in cases of bacterial meningitis (1) the existing data are inadequate to assess the effect of a short delay of therapy on mortality and morbidity; (2) a short period of antibiotic therapy prior to LP does not change cerebrospinal fluid (CSF) white blood cell count, protein, or glucose; (3) the yield of CSF gram stain and culture may be somewhat reduced by a short period of antibiotic therapy, but these tests often remain positive; and (4) adjunctive tests, including blood cultures and CSF antigen tests, can often independently identify the bacterial meningopathogen. The available evidence suggests that if bacterial meningitis is suspected and LP must be delayed, intravenous antibiotics are warranted before CSF is obtained.

Anti-Bacterial Agents↗
PubMedDate not supplied

Treatment of typhoid fever and other systemic salmonelloses with cefotaxime, ceftriaxone, cefoperazone, and other newer cephalosporins.

Third-generation cephalosporins have been considered for the treatment of systemic salmonelloses because of emerging resistance among Salmonella species to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole. Twelve patients with typhoid/paratyphoid fever, nine with nontyphoid salmonella bacteremia, and two with Salmonella meningitis were treated with cefotaxime; one leukemic patient with Salmonella dublin bacteremia received ceftizoxime. All infections were cured except for one in a patient with sickle cell anemia; this patient's illness recurred but was cured with a second course of cefotaxime followed by ceftriaxone. A review of the literature documented cures with cefotaxime in 50 of 61 patients with typhoid/paratyphoid fever, all of four with salmonella osteomyelitis, 12 of 14 with salmonella meningitis, and 44 of 49 with non-typhoid salmonella bacteremia. Ceftriaxone and cefoperazone cured, respectively, 23 of 25 and 32 of 33 patients with typhoid/paratyphoid fever. The relapse rates of typhoid fever treated with cefotaxime, ceftriaxone, and cefoperazone were 6%, 4%, and 0%, respectively. Cefotaxime, ceftriaxone, and cefoperazone are acceptable alternative antibiotics for the treatment of salmonelloses caused by multiresistant organisms.

Adolescent↗
PubMedDate not supplied

Use of trimethoprim-sulfamethoxazole in pediatric infections: relative merits of intravenous administration.

Trimethoprim-sulfamethoxazole (TMP-SMZ) has traditionally been employed as an oral formulation for infections in ambulatory pediatric patients. However, therapeutic concentrations of TMP and SMZ in serum and CSF are more consistently attained after intravenous administration. Serum half-life increases with the age of the child, and few significant toxic effects are observed with intravenous administration. Either the necessity to optimize bioavailability because of the underlying seriousness of disease or a desire to avoid other drugs that may be responsible for adverse reactions or hypersensitivity should direct the clinician to administer an intravenous preparation. Serious pediatric infections that might warrant the consideration of intravenous TMP-SMZ include shigellosis, salmonellosis, typhoid fever, nocardiosis, gram-negative bacillary septicemia or meningitis, and infections due to Pneumocystis carinii and malarial parasites. Infections due to Listeria will respond to TMP-SMZ, and infections due to Citrobacter diversus, Acinetobacter species, Pseudomonas cepacia, and Flavobacterium meningosepticum are especially susceptible to TMP-SMZ.

Age Factors↗
PubMedDate not supplied

Antibiotic treatment of acute shigellosis: failure of cefamandole compared with trimethoprim/ sulfamethoxazole and ampicillin.

Intravenously administered ampicillin (AMP), trimethoprim-sulfamethoxazole (TMP-SMX) and cefamandole (CEF) were evaluated in 30 children with shigellosis: 11 children received AMP, 10 TMP-SMX, and 9 CEF for a maximum of five days. Discharge criteria included; afebrile greater than 12 hrs, less than 9 stools/day, absence of seizures, and adequate oral intake. AMP or TMP-SMX patients required significantly fewer median days to meet discharge criteria than those who received CEF. AMP and TMP-SMX patients had fewer median days with fever (one day each) compared with CEF (five days). On day five, 7 of 8 CEF, 3 of 10 AMP and 2 of 9 TMP-SMX treated patients remained culture positive. Inhibitory concentrations against all Shigella isolates from CEF patients all were less than or equal to 0.4 microgram CEF/ml. Intravenous TMP-SMX was equivalent to AMP in treatment of children with shigellosis, while CEF was ineffective despite in vitro activity. Clinical and bacteriologic responses were achieved with AMP and TMP-SMX in the majority of patients with less than 5 days of intravenous therapy.

Ampicillin↗
PubMedDate not supplied

Reactions to booster pneumococcal vaccination in patients with sickle cell disease.

Repeat (booster) pneumococcal vaccination was administered to 32 patients with sickle cell disease in a double blind, placebo-controlled crossover study as early as 2.3 years after initial immunization. A significantly greater proportion of patients reported local pain, swelling or redness after booster, as compared to that after placebo (P less than 0.001), and pneumococcal antibody titer before vaccination was the predominant predictive variable for the development of fever, local pain and swelling after booster. A comparison of reaction rates following primary or booster immunization showed no significant differences in the frequency of reported symptoms except for muscle pain which occurred less frequently after booster (P less than 0.005). The concern for adverse reactions after repeat pneumococcal vaccination should not be an obstacle to the pursuit of further studies on the efficacy of pneumococcal vaccine and booster responses.

Adolescent↗
PubMedDate not supplied

Treatment of bacterial meningitis with ceftazidime.

Ceftazidime was prospectively evaluated in the treatment of bacterial meningitis in 19 pediatric patients. Haemophilus influenzae type b (HIB) was the etiologic agent in 17 patients, and Streptococcus pneumonia and Neisseria meningitidis were the etiologic agents in one patient each. Ceftazidime was administered intravenously in a dosage of 150 mg/kg/day divided into eight hourly doses for a mean of 15 days (range, 14 to 22 days) for H. influenzae type b meningitis. The clinical and microbiologic response was appropriate in all cases. The mean ceftazidime CSF concentration was 6.7 micrograms/ml at approximately 2 hours following iv infusions. This concentration was 16- to greater than 100-fold the minimal bactericidal concentration determined for the isolated pathogens. These preliminary observations support ceftazidime as a candidate cephalosporin for the treatment of bacterial meningitis caused by H. influenzae. Additional study is required to further define its role in meningitis caused by S. pneumoniae and N. meningitidis.

Adolescent↗