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Biomedical subjects

O V Martinez

Publications and source records attributed to O V Martinez.

At least 19 recordsLinked to original sources
PubMed2003

Incidence of clostridial contamination in donors' musculoskeletal tissue.

Reports of infection by Clostridium sordellii associated with allograft transplantation have generated considerable interest. We report our experience in recognising clostridial contamination in cadaver donors of musculoskeletal tissue. Tissues obtained from 795 consecutive donors were excised using standard surgical techniques. Samples of blood and bone marrow were also obtained. Donors with clostridia recovered from any site were matched with the preceding donor without clostridia as a procedural and environmental control. The histories of the donors were analysed to determine which variables had a relationship to contamination by running a contingency table and chi-squared test on the variables against the event of a donor being contaminated. Sixty-four donors (8.1%) had clostridia, most commonly C. sordellii. Clostridia were grown from the blood, marrow and tissue samples of 52, 37 and 30 donors, respectively. In eight cases, they were cultured from the tissue samples alone. There was no significant difference in age or gender between the contaminated donors and the control group. Open wounds were more common in control than in contaminated subjects, but only death by drowning in the contaminated group was statistically significant (p = 0.02). The time between death and the excision of tissue which was contaminated (16 hrs 10 mins) compared with control (11 hrs 10 mins) donors was also significant (p < 10(-6)). We conclude that there is clostridial contamination in a significant number of tissue donors, particularly with increasing time between death and tissue excision. Among the most commonly encountered species is C. sordellii. Multiple microbiological cultures, including blood, are necessary in order to identify clostridial contamination.

Adolescent↗
PubMed1994

Tissue distribution of antibiotics in the intervertebral disc.

STUDY DESIGN: This study analyzed the distribution of antibiotics within the intervertebral disc of rabbits. Specimens were tested with specific antibodies against antibiotics using an immunofluorescent technique. OBJECTIVES: The results were correlated to provide a rationale for perioperative prophylaxis of infection. SUMMARY OF BACKGROUND DATA: Several groups of investigators and the recent data from our laboratory showed quantitative changes in penetration of antibiotics into intervertebral disc. No previous study has assessed antibiotic distribution in anulus fibrosus and nucleus pulposus. METHODS: Discs were obtained from rabbits after intravenous injection of penicillin or gentamicin. Antibiotics were localized in tissue sections using specific antibodies with a immunofluorescent method. RESULTS: Penicillin (negatively charged) and gentamicin (positively charged) penetrated the neutrally charged anulus fibrosus, but penicillin had less ability than gentamicin to penetrate into the negatively charged nucleus pulposus. CONCLUSION: Our data suggest that penetration and distribution of antibiotics into avascular intervertebral disc is significantly influenced by the charge of antibiotics.

Animals↗
PubMed1993

Penetration of glycopeptide antibiotics in nucleus pulposus.

The penetration of the glycopeptide antibiotics vancomycin and teicoplanin into the nucleus pulposus of rabbits was studied. Blood samples were obtained at 0.5, 1, 4, 8, and 24 hours after intravenous administration of 30 mg/kg vancomycin or 16 mg/kg teicoplanin. Concentrations of antibiotics were determined in tissue specimens and serum samples by fluorescence polarization immunoassays. Antimicrobial activity in the nucleus pulposus was determined with an agar diffusion method using a strain of Micrococcus luteus as the indicator organism. A peak concentration of vancomycin in the nucleus pulposus was attained 8 hours after drug administration. Teicoplanin reached its maximum level and plateaued 1 and 2 hours, respectively, after injection, and it remained unchanged for the rest of the study. This microbiologic analysis showed that the nucleus pulposus contained an antimicrobial level of glycopeptide antibiotics after administration. Because rabbit nucleus pulposus is similar anatomically to that of humans, these results may have implications regarding the timing and choice of antibiotic administration.

Animals↗
PubMed1987

Risk and detection of pulmonary artery catheter-related infection in septic surgical patients.

Specimen cultures were evaluated in 49 catheterized patients who had a known focus of infection (primarily intra-abdominal peritonitis). Bacteria were recovered from 2% of flush solutions, 14% of transducer domes, 18% of diaphragms, and 24% of cardiac output fluids; however, these bacteria were not found in cultures of the pulmonary artery (PA) catheter segments. The rates of positive PA catheter-aspirate cultures were 30.6% on day 1, 20.4% on day 2, and 32.7% on day 3 (not statistically different). PA catheter-aspirate cultures had a sensitivity of 5.7% and a positive predictive value of 30% for catheter-related infection, and 15% sensitivity and 40% positive predictive value for peripheral bacteremia. While 95% (55 of 58) of the catheter-aspirate cultures were false-positives, only 0.5% (3 of 588) were true-positives. Peripheral blood cultures were positive in 10% of the patients, but the catheter segments were sterile or grew different organisms. Arterial line cultures had zero sensitivity and predictive value to detect catheter-related infection, and 15% sensitivity and 40% predictive value to detect peripheral bacteremia. Thus, PA catheter-aspirate cultures, routine peripheral blood cultures, and arterial cultures cannot be recommended to detect PA catheter-related infection. Catheter-related infection confirmed by catheter-segment cultures was 10.2% when the PA catheters were removed after 73 +/- 6.5 (SD) h. Bacteria from catheter-segment cultures corresponded to those from the primary infection site.

Bacteria↗
PubMed1986

Bacteriuria in the catheterized surgical intensive care patient.

A prospective microbiologic evaluation of the urine was conducted on 100 catheterized ICU patients. Eight subjects had positive initial bladder urine cultures and were eliminated from further study. The remaining 92 patients were catheterized for up to 22 days, mean 4.8 +/- 4.3 (SD). During the first 5 days, 57 (62%) patients completed the surveillance protocol; seven (12.3%) of these had bladder bacteriuria. Of 20 patients with positive urine cultures, six had microorganisms in the collection bag urine alone. The remaining 14 had organisms both in the bladder and in the bag urine. The urine collection bag was the apparent source of microorganisms in the bladder urine in only three cases. The daily incidence of new cases and the cumulative rate of bladder bacteriuria remained below 7% and 22%, respectively, during the first week of catheterization. These rates are similar to those previously reported for various other patient groups outside the ICU setting. Frequent microbiologic monitoring of the urine seems to be unnecessary for most ICU patients because of the short duration of catheterization.

Adult↗
PubMed1986

Incidence of microbial colonization in open versus closed delivery systems for thermodilution injectate.

The incidence of microbial colonization of injectate was studied in open and closed delivery systems used for thermodilution measurement of cardiac output. Patients with pulmonary artery catheters were prospectively randomized to receive either open two-bottle systems or closed systems. Paired cultures of injectate solution were withdrawn through the stopcock at the time of the initial set-up and every 12 h for 48 h. Injectate from eight (35%) of 23 patients with the open system and one (5%) of 20 patients with the closed system yielded a positive culture (p less than .05). Thirteen (10%) of 129 pairs of cultures were positive from the open system, compared to one (0.9%) of 111 pairs from the closed system (p less than .01). There was no statistically significant difference in the number of cardiac output injections between the two groups, but patients having more than the mean number of injections for cardiac output measurement had a significantly (p less than .05) greater likelihood of positive injectate cultures.

Bacteriological Techniques↗
PubMed1985

Postmortem bacteriology of cadaver tissue donors: an evaluation of blood cultures as an index of tissue sterility.

Microbiological cultures were performed on the blood and bone marrow of 239 cadaver bone donors and 58 "beating heart cadaver" organ donors who had been asymptomatic of sepsis. The incidence of positive blood cultures was significantly lower among the "beating heart cadaver" donors (8.6%) as compared to other donors from whom tissues were excised up to 30 hr postmortem (38%). Microorganisms were isolated from the bones of 82 of 148 (55.4%) bone donors as well as from 36 of 53 (67.9%) "beating heart cadaver" donors who had negative blood cultures. The majority of microbial species recovered from the blood and bone marrow belonged to species normal to the skin microflora (coagulase-negative staphylococci, Bacillus and Propionibacterium species). Species of Clostridium were the second most common organisms isolated from the blood. Blood cultures alone were not useful as indicators of sepsis in cadaver tissue donors or as an index of the sterility of the tissues excised for transplantation.

Bacteriological Techniques↗
PubMed1984

Biliary excretion of aztreonam in patients with biliary tract disease.

The biliary excretion of aztreonam was studied in 10 post-cholecystectomy patients with T-tube biliary drainage (group A) and four other subjects with obstructive biliary tract disease who had recent placement of external biliary drainage (group B). Maximum biliary levels ranged from 9.7 to 88.2 micrograms/ml (mean, 42.9 +/- 7.9 micrograms/ml) and occurred 2.4 h after injection of a single 1-g dose intravenously. Peak biliary levels observed in group B patients were approximately one-third those in group A. Cumulative 12-h biliary excretion (group B) accounted for 0.18 +/- 0.06% of the total dose. In the same period, urinary excretion accounted for 65 to 72% of the total dose. The lower biliary levels of aztreonam observed in group B patients relative to those in group A suggest that in patients with total biliary tract obstruction the liver may not recover full secretory capacity, at least within 3 to 7 days after biliary decompression.

Adult↗
PubMed1984

Ampicillin versus cefamandole in biliary tract surgery. A prospective, randomized clinical and bacteriological study.

A prospective, randomized study was conducted on 219 surgical patients with biliary tract disease. There were 100 patients undergoing elective biliary surgery, and 119 others with suspected biliary sepsis who were assigned to Prophylactic or Therapeutic clinical categories, then randomized into ampicillin or cefamandole treatment groups. Organisms resistant to the antibiotics given were found less often among patients in the cefamandole groups than among those in the ampicillin groups. No postoperative wound or intra-abdominal sepsis (IAS) occurred in the Prophylactic category. In the Therapeutic category there were two cases (3.2%) of wound and IAS in the ampicillin group and one case (1.8%) of wound infection in the cefamandole group. Overall, cefamandole showed superior coverage in vitro against the biliary flora, but both drugs were equally effective in maintaining a low incidence of postoperative sepsis as well as a minimal number of febrile or total hospital days. The authors suggest that the choice of antimicrobials may not be as critical as effective surgical management in the prevention of septic complications following biliary tract surgery.

Adult↗
PubMed1982

The effect of some beta-lactam antibiotics on Escherichia coli studied by flow cytometry.

The effects of three beta-lactam antibiotics on Escherichia coli were studied by means of flow cytometry. Since these agents block bacterial cell wall synthesis in such manner as to prevent septal formation without appreciably affecting nucleic acid synthesis, the resulting cell elongation caused by these agents can be assessed by nucleic acid fluorescent staining. It was shown by this technique that the somatic effects of cefazolin, cefamandole and moxalactam were related both to the antibiotic concentration and time of exposure to the drugs and were observable within 30 minutes of the initial exposure of the cultures to these agents. These results demonstrate that fluorescent cytometry can provide accurate assessment of the effects of compounds that inhibit cell wall formation. This technology could be a useful tool for comparing antibiotic somatic effects on bacteria and for rapidly and reliably determining their sensitivity and resistance to these agents.

Anti-Bacterial Agents↗
PubMed1982

The effect of osmotic stabilizers on the radiometric detection of osmotically sensitive populations of some gram-negative bacteria.

The effect of four osmotic stabilizers on the radiometric detection of osmotically sensitive populations of E. coli, S. typhimurium, and E. cloacae was studied. The addition of sucrose, sorbitol, glycerol, or ethylene glycoll to BACTEC 6B blood culture medium failed to improve the sensitivity of the system and produced an inhibitory effect on the level of 14CO2 released by organisms previously exposed to lysozyme and ECTA or to penicillin followed by the lysozyme treatment. The same effect was observed both in blood free media and simulated blood cultures. The addition of proline to sucrose-containing hypertonic media had no effect on growth index readings.

Carbon Dioxide↗
PubMed1981

Biliary excretion of moxalactam.

The biliary excretion of moxalactam was studied in 11 postsurgery patients who had indwelling T-tubes inserted in their common bile ducts. Peak levels of moxalactam in the bile reached mean levels of 33.7 +/- 11.1 and 173.7 +/- 67.0 micrograms/ml 2 h after intravenous administration of a single 500- or 2,000-mg dose, respectively. In 5 of the 10 patients given the 2,000-mg dose, peak moxalactam concentrations in the bile were 2 to 12 times higher than simultaneous serum levels, but considerable variation in the biliary excretion of moxalactam was observed among the individual patients.

Bile↗
PubMed1980

The use of a radiometric technic for the rapid detection of contaminated tissue specimens from burned patients.

The 14CO2-dependent BACTEC system for the detection of bacteria in fluid specimens was adapted for the semiquantitative bacteriologic screening of solid tissue samples from 33 burned patients. The radiometric system detected 87% of all specimens harboring > 10(5) organisms per gram of tissue and 100% of all heavily contaminated specimens (> 10(8) organisms per gram) within eight hours of incubation. The BACTEC radiometric system correlated well (98.1%) with conventional culture methods in the detection of all contaminated samples. No false-positive result was obtained from sterile tissue specimens.

Bacteria↗
PubMed1979

Bacteriologic and systemic effects of intraoperative segmental bowel preparation with povidone iodine.

A technique for intraoperative segmental preparation of the large bowel, using 10% povidone iodine, was evaluated in 25 patients undergoing elective colon resection. Qualitative and quantitative bacteriology was obtained from the normal bowel content and from segments of colon treated with povidone iodine or normal saline. Forty-five of 50 segments treated with povidone iodine demonstrated no growth, whereas the segments injected with normal saline maintained bacterial counts of 3.5 x 10(8) colony forming units per milliliter. There were no septic complications in this group of patients and the levels of triiodothyroninc and thyroxin remained unchanged despite a substantial absorption of iodine, as demonstrated by protein-bound iodine determinations. Intraoperative segmental preparation of the colon with 10% povidone iodine is a simple technique that may be useful in the enhancement of other methods of bowel preparation by further reducing the endogenous bacterial inoculum at the time of transection of the colon.

Adult↗
PubMed1979

Effect of osmotic stabilizers on radiometric detection of cell wall-damaged bacteria.

The effect of osmotic stabilizers on the 14CO2-dependent radiometric detection of cell wall-damaged Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa was studied in BACTEC 14C-labeled blood culture medium. The organisms were previously exposed to cefamandole or carbenicillin at 63 to 80% of the minimum inhibitory concentrations. The addition of 10% sucrose, 2.2% glycerol, and 2.2% ethylene glycol to the medium failed to reduce the time required for detection and diminished the amounts of 14CO2 released by the growing cultures. Viable counts made after 4 to 7 h of incubation showed a decreased culture density in osmotically stabilized media as compared with saline or Ficoll controls. Sucrose and Ficoll had little or no inhibitory effect on 14CO2 evolution by P. aeruginosa. The osmotic stabilizers tested did not seem to improve the survival of the bacterial inoculum and failed to increase the sensitivity of the radiometric system of detection.

Blood↗