Alice N. Bessman

Prevalence of Corynebacteria in Diabetic Foot Infections

OBJECTIVE Microbiological flora of diabetic foot infections are usually polymicrobial and frequently include bacteria of the Corynebacterium sp. (diphtheroids). The purpose of this study was to determine the prevalence of these bacteria in both deep and superficial cultures in diabetic patients with foot infections. RESEARCH DESIGN AND METHODS The charts of 50 patients of successive admissions to the Orthopedic-Diabetes Service at our hospital were reviewed to obtain the following data: age, sex, ethnic origin, method of treatment of diabetes, blood glucose level, prior antibiotics, and reports of cultures taken from bedside and intraoperative sites. Data were analyzed to compare the prevalence of diphtheroids in reliable versus nonreliable cultures and the influence of other parameters on the presence of these organisms. RESULTS Fourteen of 19 (74%) of the intraoperative specimens grew diphtheroids compared with 25 of 65 (39%) of the bedside cultures, a highly significant difference. In addition, there was a somewhat greater occurrence of diphtheroids in women compared with men. The likelihood that contamination is the cause for the presence of diphtheroids is highly unlikely, because one arm of the study included cultures derived from deep tissue at the time of the surgical procedure (i.e., the intraoperative cultures). Cultures always grew at least one other organism in addition to the diphtheroid. CONCLUSIONS Corynebacteria, commonly known as diphtheroids, are present as a part of the polymicrobial flora in a large percentage of diabetic patients with foot infections. Because the diphtheroids were identified in culture material taken in the operating room or at the time of incision and drainage in a higher percentage of patients than in specimens from superficial cultures, it is highly unlikely that they are contaminants.

Persistence of polymicrobial abscesses in the poorly controlled diabetic host

Polymicrobial infections are frequently found in soft tissue infections of the lower extremities in diabetic patients. The relative susceptibility to and persistence of soft tissue polymicrobial infections of diabetic and nondiabetic mice using bacteria commonly found in clinical foot infections were studied. Subcutaneous abscesses were induced in three groups of diabetic and nondiabetic mice using: (1) E. coli and enterococcus, (2) enterococcus and Bacteroides fragilis (B. fragilis), and (3) E. coli and B. fragilis. Abscesses were removed at 1 and 2 wk for total colony counts. At 1 wk, there was a significantly greater bacterial growth in the abscesses of the diabetic mice compared with the nondiabetic mice only in the group injected with enterococcus and B. fragilis. There were significantly higher colony counts in the diabetic compared with the nondiabetic mice in all three groups at 2 wk after injection of the bacteria. Two weeks after injection of inocula containing B. fragilis, both in combination with E. coli or enterococcus, all nondiabetic mice had eradicated B. fragilis from the abscesses, but significant numbers of B. fragilis persisted in the abscesses of the diabetic mice. In the diabetic mice, the presence of enterococci was more synergistic for growth of B. fragilis than was the presence of E. coli. These studies demonstrate that the bacteria of polymicrobial soft tissue infections persist for a longer period of time in the diabetic compared with the nondiabetic host. In addition, B. fragilis has increased pathogenicity in the diabetic compared with the nondiabetic host, particularly in the presence of enterococci.

Bacteremia in Diabetic Patients with Infected Lower Extremities

Eleven cases of bacteremia in diabetic patients with infected lower extremities at Rancho Los Amigos Hospital (RLAH) were observed over a 34-mo period. The yearly incidence was 0.6% of admissions to the Ortho-Diabetes service. Aerobic bacteria were recovered in six cases and anaerobic bacteria in five. Bacteroides fragilis was isolated four times, Staphylococcus aureus three times, and nonfragilis Bacteroides sp., Escherichia coli, group B streptococcus, and viridans streptococcus were each seen once. Ten of the 11 patients were febrile at the time of bacteremia. Clinical, laboratory, radiologic, and ultrasonographic parameters were comparable in patients with aerobic and anaerobic bacteremia, and between bacteremi patients and nonbacteremic controls. Fever, however, was significantly more frequent in bacteremic patients. Foul-smelling lesions were seen in two of the five patients with anaerobic bacteremia, and in none of the patients with aerobic bacteremia. Postoperative B. fragilis bacteremia was observed to be transient and resolved without definitive therapy in one patient. Appropriate antibiotic therapy in 10 patients together with surgical intervention in eight cases resulted in resolution of the infection in the remaining patients.

Comparison of continuous and intermittent intravenous insulin therapies for diabetic ketoacidosis.

SummaryTwenty-six diabetic ketoacidotic patients were treated with 3 different intravenous insulin regimes. Group (A) received 50 U initially and at 2 h intervals. Groups (B) and (C) were given continuous infusions of 10 and 2 U per hour respectively without added albumin. In addition, Group (C) received a loading dose of 3 U. The dosages were reduced when serum glucose declined to 300 mg/100 ml. Criteria for admission to the study included a plasma glucose above 350 mg/100 ml, plasma bicarbonate less than 9 mmol/l, serum ketone-bodies detectable by nitroprusside test at 8-fold or greater dilution, and arterial pH less than 7.3. The rate of normalization of blood glucose, bicarbonate, ketone bodies, and pH did not differ between Group (A) and (B). In contrast, the changes in pH, glucose, and ketone-bodies were significantly slower in Group (C). Two patients of Group (C) had worsening of these biochemical parameters during the first 6 h. They were treated successfully with regimen A. At 2 h, plasma immunoreactive insulin concentrations were 47±15, 135±19, and 25±3 μU/ml in previously untreated patients in Groups (A), (B) and (C), respectively. Potassium requirements to maintain adequate blood levels were significantly higher in Group (A). The data demonstrate that 10 U/h infusion of insulin is as effective as 50 U administered intravenously every 2 h. The amount of insulin infused should be reduced to 5 U/h when plasma glucose has declined to 300 mg/100 ml. The recovery is slow, plasma insulin concentration is inadequate and treatment failure may occur with very low insulin doses (2 U/h).

Thyroid autoimmunity in Type 2 (non-insulin-dependent) diabetic patients of Caucasoid, black and Mexican origin

SummaryFour hundred and forty-nine patients with Type 2 (non-insulin-dependent) diabetes mellitus and 270 control subjects from Caucasoid, Mexican and black origins were screened for the presence of thyroid microsomal antibodies. Mexican female control subjects had a significantly higher frequency of thyroid microsomal antibodies when compared with black female controls (21% versus 6%, p <0.01). Type 2 diabetic patients did not have a higher frequency of thyroid microsomal antibodies when compared with their sex- and race-matched control counterparts. The subgroup of diabetic patients who required insulin for the control of their blood glucose did not have a higher frequency of thyroid microsomal antibodies when compared with non-insulin-requiring diabetic patients. In conclusion autoimmunity against thyroid gland, as manifested by thyroid microsomal antibodies, is not more common in Type 2 diabetic patients when compared with sex- and race-matched control subjects.

Effect of hemodialysis on red cell organic and inorganic phosphates.

Red cell 2,3 diphosphoglyceric acid (DPG), total nucleotide phosphate, inorganic phosphate, and plasma inorganic phosphate were measured at the onset and termination of 22 hemodialyses performed for chronic renal failure in 19 patients. Plasma inorganic phosphate decreased from a mean of 2.05 mM/liter ± 0.14 to 1.26 mM/liter + 0.09 (p < 0.005) while intracellular inorganic phosphate fell from 1.76 mM/liter ± 0.12 RBC water to 1.21 +0.08 mM/liter ( p< 0.005). Mean DPG was 6.37 mM/liter RBC ±0.23 at the start of the dialysis and 6.08 mM/liter ± 0.24 at the termination (p=n.s.). Mean nucleotide concentration was 5.90 mM phosphorous content/liter RBC ± 0.26 at the start and 5.95 mM/ liter ± 0.21 at the end (p=n.s.). Although there were significant decreases in intracellular and plasma inorganic phosphate concentrations immediately following dialysis, neither the DPG nor nucleotide phosphate concentrations were significantly altered by this short-term procedure. Red cell water inorganic phosphorous rapidly attained identical concentration with plasma water inorganic phosphorous.

Effect of nortestosterone decanoate on red cell 2,3 diphosphoglycerate and hematocrit in hemodialysis patients

The effects of intramuscular 200‐mg nortestosterone decanoate (ND) on red cell 2,3 diphosphoglycerate (DPG) concentration and packed cell volumes (PCV) were compared in 9 patients undergoing chronic hemodialysis for renal failure and in 18 control patients undergoing hemodialysis but not receiving ND. Subjects had received the drug 4.3 ± 0.3 (SEM.) months at the time of DPG determinations. DPG was similar in treated patients and in the control subjects: 6.27 ± 0.22 mM/L RBC and 6.16 ± 0.23 mM/L RBC, respectively. The initial PCV was also similar: 21.72% ± 1.36 and 20.13% ± 0.91. Although the mean PCV during treatment was higher for 5 of 9 ND‐treated patients (p < 0.01), the final PCV prior to termination of therapy was greater than the initial pretreatment PCV in only 2 of these 5 patients (p > 0.05). We conclude that 200 mg ND weekly has no effect on the red cell DPG and a transient unsustained effect in raising the PCV in male chronic hemodialysis patients over a 5‐month period of treatment.

The relation of diabetic control to in vivo pH of soft tissue abscesses

It has been shown that induced soft tissue abscesses have a lower intra-abscess pH in the uncontrolled diabetic host than in the nondiabetic control. These differences were felt to be secondary to alterations in white cell metabolism. The current study compares the intra-abscess pH in three groups of mice: (I) nondiabetic, (II) untreated diabetic, and (III) insulin-treated diabetic. Diabetes was induced with streptozotocin in male white mice. The bacteria used to induce the abscesses were a combination of B. fragilis and Enterococcus. The blood glucose values of groups I, II, and III were 189 mg% (+/- 20.3), 256 mg% (+/- 121.9), and 712.8 mg% (+/- 169.7), respectively. None of the animals were ketotic, and peritoneal pH (reflecting systemic pH) showed no significant differences between groups. There were no significant differences in colony counts between any groups. The intra-abscess pH values of groups I, II, and III were 6.97 (+/- 0.26), 6.85 (+/- 0.41), and 6.08 (+/- 0.70). The differences in intra-abscess pH and blood glucose levels were all significantly different from each other when all three groups were compared. The insulin-treated mice tended to return to normality but had the widest spread of values. Since a decrease in intra-abscess pH has been felt to be a reflection of white cell activity, our studies may be the first to demonstrate an in vivo effect of insulin on white cell activity.