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Biomedical subjects

K S Scher

Publications and source records attributed to K S Scher.

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

The septic foot in patients with diabetes.

Sixty-five lower-extremity amputations were performed as a result of sepsis in diabetic patients during a 3-year period. Chronic plantar ulcer was the most frequent cause of infection. Other causes of infection included ischemic gangrene, trauma, and web space fissures. Advanced ischemia was infrequent; only 21 (32.3%) had ankle-brachial indices (ABI) less than 0.5. Eight (23.5%) deaths and 12 (35.3%) stump failures followed 34 amputations where the stump was closed, compared with no deaths and 4 (12.9%) stump failures when open amputations were done (p less than 0.02). Partial foot amputations with aggressive local debridement resulted in healing in 10 (71.4%) of 14 cases with revision or grafting. Guillotine transmalleolar amputation is advised when foot salvage is not possible, because only 1 (5.9%) of 17 such procedures could not be revised to the below-knee (B-K) level, whereas 8 (33.3%) of 24 definitive, closed B-K amputations were unsuccessful (p less than 0.02). Infections were polymicrobial, with 5.8 bacterial isolates and 2.3 anaerobes recovered per patient. Anaerobic antibiotic coverage, however, failed to alter outcome. Sepsis, often without advanced ischemia, is an important cause of limb loss in patients with diabetes. Open amputations are recommended, with foot salvage possible in many cases.

Adult↗
PubMed1988

Emergence of antibiotic resistant strains of Bacteroides fragilis.

From 1981 to 1986, antibiotic susceptibility was tested by the agar dilution method in 534 isolates of Bacteroides fragilis organisms recovered from clinical specimens. Drugs evaluated included penicillin, ampicillin, tetracycline, clindamycin, metronidazole and chloramphenicol. Based on in vitro testing, tetracycline, ampicillin and penicillin were ineffective against B. fragilis because of high rates of resistance to these agents (74 per cent tetracycline resistant, 80 per cent ampicillin resistant and 89 per cent penicillin resistant). Throughout the five years of the study, 5.1 per cent of the organisms studied were resistant to clindamycin compared with 2.1 per cent resistant to metronidazole (p less than 0.01) and 0.9 per cent resistant to chloramphenicol (p less than 0.001). More important than the relative resistance rates to the various antibiotics is the observation that this is a dynamic process that is influenced by local practices of administering antibiotics. In 1981, the first year of the survey, no clindamycin resistant B. fragilis isolates were identified; by 1986, 7.8 per cent of the strains proved resistant to this antibiotic. Similarly, no metronidazole or chloramphenicol resistant organisms were demonstrated in 1981 or 1982; thereafter, resistance to these two drugs was noted with increasing frequency each year. The emergence of B. fragilis strains that are resistant to the antibiotics in current use mandates the surveillance of the local susceptibility data to identify important trends. When increasing rates of resistance are noted to one antibiotic, alternative regimens can be used.

Ampicillin↗
PubMed1987

Implications of emergency operations on the colon.

The records of 137 patients undergoing elective colonic operations and 45 patients requiring emergency large bowel operations were reviewed. The mortality rate was 37.8 percent after emergency operations compared with 5.1 percent after elective operations (p less than 0.001). Patient age was not a significant prognostic variable although physiologic status of the patient had a high correlation with both morbidity and mortality. Complications followed 86.7 percent of the emergency operations and 57.7 percent of the elective operations (p less than 0.001). Respiratory failure, renal and hepatic dysfunction, and cardiac events more frequently followed emergency colonic operations. Intraabdominal complications developed after 57.8 percent of the emergency operations compared with 29.9 percent of the elective operations (p less than 0.005). Colonic resection and primary anastomosis in the elective setting was associated with a 7.9 percent mortality rate. A large bowel anastomosis during an emergency operation resulted in a 70 percent mortality rate (p less than 0.001). When emergency colonic operation included creation of a colostomy the mortality rate was 34.4 percent. Although this mortality rate was substantial, it was significantly better than the 70 percent rate that followed attempted anastomosis under unfavorable circumstances (p less than 0.02).

Age Factors↗
PubMed1987

Complications of biliary surgery.

Procedures on the gallbladder and extrahepatic biliary tract were the most frequently performed operations in a series of 1500 consecutive abdominal operations done in community hospitals. The operative mortality rate for elective cholecystectomy was 0.3 per cent. The complication rate was 21.4 per cent for cholecystectomy. Patients requiring emergency cholecystectomy had significantly more urinary tract and intra-abdominal problems than those patients who underwent surgery electively. Operative cholangiography was performed during 20.3 per cent of the elective cholecystectomies. There were no biliary tract complications among the cholecystectomy patients who had cholangiography. When this study was not performed, 1.5 per cent of the patients had postoperative bile duct problems. Older surgeons (greater than 60 years of age) and high volume surgeons (greater than 300 cases/year) were significantly less likely to employ cholangiography. The mortality rate for elective common duct exploration was 4.4 per cent, with a complication rate of 60 per cent. There was a 13.3 per cent incidence of retained stones after choledochotomy, though this problem was readily managed by percutaneous extraction through the T-tube tract. Complex biliary tract procedures were performed electively without mortality, though the complication rate for these procedures was 35.3 per cent. Two-thirds of the patients undergoing complex biliary tract operations on an emergency basis died. Board certified general surgeons had the same mortality and complication rates for cholecystectomy as well as common bile duct exploration. Noncertified surgeons had significantly more intraabdominal complications after complex biliary tract procedures compared to their board certified colleagues.

Biliary Tract Surgical Procedures↗
PubMed1986

Duration of antibiotic prophylaxis. An experimental study.

An animal wound model was used to evaluate single dose cefazolin, multiple dose cefazolin, and single dose cefonicid in the prevention of wound infection. Incisions made in Swiss-Webster mice were contaminated with either Staph. aureus (1.94 X 10(8) colony forming units) or E. coli (4.39 X 10(8) colony forming units). Five experimental groups were studied. Group I encompassed control animals given saline solution, Group II animals given 10 mg cefazolin preoperatively, Group III animals given 10 mg of cefazolin preoperatively and postoperatively, Group IV animals given 10 mg of cefonicid preoperatively, and Group V animals given 20 mg of cefonicid preoperatively. All medications were given by intraperitoneal injection. Antibiotics were given 1 hour before operation. Postoperative doses were given 4 hours after operation. Incisions were opened 48 hours after surgery and wound bacterial concentrations were determined. After both Staph. aureus and E. coli contamination, each of the four cephalosporin regimens significantly reduced the mean wound bacterial concentrations compared with that of the control animals (p less than 0.001). Each of the four cephalosporin regimens also significantly reduced the number of infected wounds compared with that of the control subjects (p less than 0.001). No significant differences were noted among the four antibiotic regimens with respect to mean wound bacterial concentration or infection rate. In the context of this model, a single dose of cefazolin seems to be equally effective as multiple doses of the drug for surgical prophylaxis. Extended half-life cephalosporins, like cefonicid, do not appear to be more effective than a single dose of cefazolin, which is a much less expensive antibiotic.

Animals↗
PubMed1986

Anaerobic coverage for wound prophylaxis. Comparison of cefazolin and cefoxitin.

An experimental wound model has been used to evaluate the effectiveness of cefazolin and cefoxitin in the prevention of wound infection. Incisions were contaminated with Staph. aureus, E. coli, or a standardized fecal suspension. Regardless of the contaminant employed, the prophylactic use of either cefazolin or cefoxitin yielded lower wound bacterial concentrations and fewer infections compared with treatment with placebo. Cefazolin proved just as effective as cefoxitin in preventing infection when wounds were contaminated with Staph. aureus or E. coli. Although cefoxitin is the only cephalosporin that offers anaerobic coverage, its prophylactic administration when wounds were contaminated with a standardized fecal suspension did not significantly alter wound bacterial concentrations or infection rates compared with cefazolin. The data from our animal wound model suggest that prophylactic anaerobic coverage is not necessary.

Animals↗
PubMed1986

The significance of clostridial isolates in intra-abdominal sepsis.

In order to evaluate the significance of clostridial species in intra-abdominal infections, the bacteriology records of three hospitals were reviewed during a period of five years. Included in this report were 41 patients from whom clostridial species were recovered from specimens of free peritoneal fluid, abscess cavities or bile. Seven patients died for a mortality rate of 17.1 per cent. Most patients had polymicrobial infections of which clostridial organisms were one of the several anaerobes isolated. Clostridium perfringens was the single most frequently noted species, identified in 23 of the patients, but it was not associated with a different mortality rate than was observed for the other clostridial species. Clostridial bacteremia was uncommon and demonstrated in only one patient. The mean age of the patients was 56.4 years; 56.2 for males and 56.8 for females. Neither age nor sex of the patient influenced the likelihood of survival. The source of the clostridial isolates--bile, abscess cavity or free peritoneal fluid--had no effect upon the outcome. Several underlying conditions were responsible for the intraperitoneal clostridial organisms identified in this series. Only mesenteric infarction proved significantly predictive of a fatal result. Antibiotic coverage specifically directed against clostridia did not influence survival.

Abdomen↗
PubMed1986

The effect of biliary obstruction on a gram-negative bacteremic challenge: a preliminary report.

Alterations in the sequestration and destruction of bacteria were studied after 10 days of biliary obstruction. Intraperitoneal injection of radiolabeled Escherichia coli was used to study bacterial localization in rats 10 days after common duct ligation and transection or sham celiotomy. Animals were sacrificed 4 hours later and uptake by liver, spleen, lung, and kidney were studied with a scintillation counter. No significant difference in localization between the two groups was noted. Bacteremia was induced in a second set of animals and quantitative bacterial organ cultures were performed. Significantly more viable organisms were identified in lung, liver, and kidney of animals that underwent common duct ligation and transection, when compared with controls that underwent sham celiotomy. This suggests that there is a defect in bacterial killing after 10 days of biliary obstruction. The inability to effectively clear and kill gram-negative bacteria in patients with biliary obstruction may account for some of the clinical complications seen in this patient population.

Animals↗
PubMed1986

Acute acalculous cholecystitis complicating aortic aneurysm repair.

In a series of 374 consecutive abdominal aortic aneurysmal repairs, the incidence of acute acalculous cholecystitis was 1.1 per cent. This complication occurred in only one of 352 patients (0.3 per cent) after elective aneurysmorraphy, as compared with three of 22 (13.6 per cent) after emergency repair of a ruptured aneurysm. This difference proved highly significant (p = 0.0001). All of the patients who had postoperative acute cholecystitis after aortic aneurysmal repair had acalculous disease. A mortality rate of 50 per cent was noted for this complication. Technetium cholescintigraphy proved the most valuable diagnostic study when acute cholecystitis was suspected.

Acute Disease↗
PubMed1985

Methods of splenic preservation and their effect on clearance of pneumococcal bacteremia.

The intravascular clearance of type 3 Streptococcus pneumoniae was studied in Sprague-Dawley rats. Sham celiotomy was performed on 20 animals while another 20 rats underwent splenectomy. Four weeks later, bacteremia was induced by intraperitoneal (IP) injection of S. pneumoniae. Serial cultures of peripheral blood were obtained. Splenectomy produced significant impairment of intravascular clearance of bacteria compared to that noted among control animals (p less than 0.01). Eighty animals were divided into four equal groups: I--splenectomy, II--50% splenectomy with the upper half left in situ connected to the short gastric vessels, III--50% splenectomy with the lower half left in situ connected to the hilar vessels, and IV--splenectomy with implantation of splenic fragments. Pneumococcus was administered IP 16 weeks later. Rats were killed 6 hours after bacterial challenge. Residual splenic tissue was weighed. There was significantly less splenic tissue in Groups II-IV than noted in sham animals after 16 weeks (p less than 0.01). The type of partial splenectomy did not significantly affect the weight of residual splenic tissue 16 weeks later. Implantation did yield viable splenic tissue, though the amount proved significantly less than that resulting from either type of partial splenectomy (p less than 0.01). Mean bacterial counts with time for short gastric (Group II) and hilar (Group III) remnant animals were significantly different from those for the asplenic (Group I) rats (p less than 0.02 and p less than 0.001, respectively). Animals with splenic implants (Group IV) were not significantly different from asplenic rats (Group I). Animals with hilar splenic remnants proved significantly different from those with short gastric splenic remnants (p less than 0.01). Partial splenectomy offers protection against pneumococcal bacteremia, though preservation of the hilar blood supply affords the most benefit. The utility of splenic implantation remains unproven.

Animals↗
PubMed1985

Inadequate tetanus protection among the rural elderly.

Three cases of tetanus occurring in a community in southern West Virginia in five years prompted a survey of the immunization status of the population of this region. An immunization history was obtained from 540 consecutive patients seen at three different health care facilities. Of these, 386 (71.5%) had received prior tetanus protection, 65 (12%) had never been immunized, and 89 (16.5%) were uncertain or had received incomplete immunization. Of the 65 nonimmunized patients, 54 (83%) were older than 50 and only 11 (17%) were younger. Compared to the total group sampled, significantly more nonimmunized patients (both male and female) were older than 50 (P less than .001). Also, significantly more of these never immunized individuals lived in rural areas (P less than .001). In a group of 222 patients identified as being at increased risk of having tetanus, 65 (29%) had never been immunized, 89 (40%) were of uncertain or incomplete status, and 68 (30.5%) had been immunized more than ten years previously. One hundred twenty (54%) high-risk patients were older than 50 and 103 (46%) were younger. Compared to the entire population sampled, high-risk patients included significantly more who were older than 50 (P less than .001). Also, significantly more high-risk patients lived in rural areas (P less than .007). When treating injured patients, it is important to recall that many older adults living in rural areas are not adequately immunized against tetanus. Such patients should receive human tetanus immunoglobulin, as well as tetanus toxoid.

Adolescent↗
PubMed1985

Which cephalosporin for wound prophylaxis? An experimental comparison of three drugs.

An experimental wound model was used to evaluate the effectiveness of cefazolin, cefamandole, and cefotaxime in the prevention of wound infection. Incisions were contaminated with Staphylococcus aureus, Escherichia coli, or a standardized fecal suspension. Regardless of the contaminant employed, the prophylactic use of either cefazolin, cefamandole, or cefotaxime yielded lower concentrations of bacteria in the wounds and fewer infections compared with treatment with saline solution. Within the context of this experimental model, cefazolin proved equally as effective as the newer and more expensive cephalosporins, cefamandole and cefotaxime.

Animals↗
PubMed1985

Infectivity of vascular sutures.

Bacterial adherence to vascular sutures was evaluated in vitro using radioactively labeled Staphylococcus aureus. The following suture materials were tested: polypropylene, silicone-treated braided polyester, and Teflon-treated braided polyester. Significantly fewer bacteria adhered to the monofilament polypropylene than either of the braided polyester sutures. There was no significant difference between silicone-treated and Teflon-treated polyester from the standpoint of bacterial adherence. Vascular sutures were evaluated in vivo using a mouse wound model. Sutures were tested with and without knots. When tested without knots, fewer bacteria were recovered from wounds containing polypropylene suture compared to either of the braided materials, although this apparent advantage did not prove to be statistically significant. When studied with knots, the differences among types of suture were much less marked and, again, not significant. The purported contribution of the monofilament structure of a suture to its infection resistance may have been overstated.

Adhesiveness↗
PubMed1985

Intraperitoneal splenic implants do not alter clearance of pneumococcal bacteremia.

The effect of intraperitoneal splenic autotransplants was studied in Sprague-Dawley rats. Twenty animals underwent total splenectomy. Splenectomy was performed in another group of 20 rats, after which the spleen was diced into 15 pieces and replaced within the leaves of the small bowel mesentery. Twelve weeks later pneumococcal bacteremia was induced by intraperitoneal injection of 5 X 10(6) Streptococcus pneumoniae. Quantitative blood cultures were obtained from the tail vein 15, 30, 45, 60, 90, and 240 minutes after injection. Mean bacterial counts with time for animals bearing splenic autotransplants were not significantly different from completely asplenic rats. At autopsy, all animals receiving splenic implants were found to have viable splenic tissue among the leaves of the small bowel mesentery. This study shows that even allowing 12 weeks for maximal regeneration, splenic autotransplants fail to significantly alter the clearance of an established bacteremia.

Animals↗
PubMed1984

A comparison of topical and systemic cefazolin for wound prophylaxis.

An experimental wound infection model was used to compare the effectiveness of topical and systemic cefazolin in the prevention of wound infection. Studies were conducted using both Staphylococcus aureus and Escherichia coli as the contaminating organisms. Regardless of the wound pathogen studied, there were no significant differences between topical and systemic cefazolin with regard to wound bacterial concentrations and the incidence of wound infection.

Administration, Topical↗