Nasal carriage of staphylococcus aureus and epidemiology of surgical-site infections in a Sudanese university hospital

Surgical site infections (SSI) due to Staphylococcus aureus among 256 male and 158 female patients (mean age, 28 years) undergoing elective surgery at the Soba University Hospital (Khartoum, Sudan) were studied. During an 11-month study period all patients were analyzed for nasal carriage of S. aureus at the time of admission. Follow-up of the development of SSI proceeded until 4 weeks after the operations. In addition, nasal swabs were obtained periodically during the same period from 82 members of the staff. In order to discriminate autoinfection from cross infection, bacterial isolates were typed by random amplification of polymorphic DNA (RAPD), pulsed-field gel electrophoresis (PFGE) of DNA macrorestriction fragments, and restriction fragment length polymorphism analysis of the protein A and coagulase genes. Preoperative cultures revealed the presence of S. aureus in the noses of 98 patients (24%). The overall number of postsurgical wound infections in the entire group was 57 (14%), 24 of which were due to S. aureus. Only 6 of the 98 nasal S. aureus carriers suffered from wound infections by the same species. In these six cases the infecting strain could not be genetically discriminated from the nasal inhabitant, substantiating autoinfection. However, nasal carriage of S. aureus is not a significant risk factor for the development of SSI in this setting (6 of 98 patients with autoinfection versus 18 of 316 patients [414 - 98 patients] with cross infection; P = 0.81), most probably due to the fact that noncarriers are at a significant and relatively large risk for acquiring an independent S. aureus SSI. The other S. aureus strains causing SSI showed a high degree of genetic heterogeneity, demonstrating that it is not an epidemic strain that is causing the SSI. Among the staff personnel screened, 47.4% did not carry S. aureus in the nose at any time during the study period, whereas 13. 2% persistently carried a single strain in the nose. Another 39.5% could be classified as intermittent carriers. When strains derived from staff personnel were genetically typed, it was demonstrated that most of the strains represented genetic variants clearly differing from the isolates causing SSI. On the other hand, possible cross colonization among staff personnel and even cross infection from staff personnel to patients or from patient to patient were demonstrated in some cases, but epidemic spread of a single strain or a few clonally related strains of S. aureus could be excluded.     

Dorsalis pedis flap donor site: acceptable or not?

The dorsalis pedis flap has been used successfully for 20 years, both as a pedicled transfer for local foot reconstruction and as a free microvascular transfer. Proponents cite the reliable vascularity, versatility, ease of harvest, and thinness. Although significant donor-site morbidity has been recognized previously, published reports have inadequately documented the long-term effects of dorsalis pedis flap harvest. The purpose of the present study was to obtain long-term follow-up data regarding the donor site on a total of 10 male patients who underwent dorsalis pedis flap harvest during the period from 1982 to 1984. Standardized questionnaires and chart reviews were completed, and physical examinations and photographs of each patient were carried out when possible. Eight patients were reviewed, and seven of them were examined and photographed (mean follow-up 13 years). All patients had initially experienced delayed donor-site healing (mean 18 months; range 3 to 36 months). In addition, soft-tissue infections (five of eight cases), osteomyelitis (one of eight cases), wound breakdown (seven of eight cases), scarring and contracture (four of seven cases), pain or other uncomfortable sensations in the foot (six of seven cases), and requirement for reoperation (three of eight cases) were significant complications of the procedure. Most patients were able to attain their preoperative level of physical activity (five of eight cases). Although generally favorable reconstructive results were obtained in this series, the long-term follow-up of donor-site healing indicates that this flap should be used with caution. In particular, delayed donor-site healing, need for wound revision, and long-term and possibly permanent donor-site symptoms are common.     

Occurrence of verocytotoxin-producing Escherichia coli O157 on Dutch dairy farms

During the period from September 1996 through November 1996, 10 Dutch dairy farms were visited to collect fecal samples from all cattle present. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. Cattle on 7 of the 10 dairy farms tested positive for O157 VTEC, with the proportion of cattle infected varying from 0.8 to 22.4%. On the seven farms positive for O157 VTEC, the excretion rate was highest in calves ages 4 to 12 months (21.2%). In a follow-up study, two O157 VTEC-positive farms and two O157 VTEC-negative farms identified in the prevalence study were revisited five times at intervals of approximately 3 months. Cattle on each farm tested positive at least once. The proportion of cattle infected varied from 0 to 61.0%. Excretion rates peaked in summer and were lowest in winter. Again, the highest prevalence was observed in calves ages 4 to 12 months (11.8%). O157 VTEC strains were also isolated from fecal samples from horses, ponies, and sheep and from milk filters and stable flies. O157 VTEC isolates were characterized by VT production and type, the presence of the E. coli attaching-and-effacing gene, phage type, and pulsed-field gel electrophoretic genotype. No overlapping strain types were identified among isolates from different farms except one. The predominance of a single type at each sampling suggests that horizontal transmission is an important factor in dissemination of O157 VTEC within a farm. The presence of more than one strain type, both simultaneously and over time, suggests that there was more than one source of O157 VTEC on the farms. Furthermore, this study demonstrated that the O157 VTEC status of a farm cannot be ascertained from a single visit testing a small number of cattle.     

The spontaneous aortocaval fistula: a complication of the abdominal aortic aneurysm. Case report and review of the literature

AIMS: (i) to compare Helicobacter pylori serology in two 70-year-old cohorts in Gothenburg, Sweden, born 21 years apart, (ii) to study H. pylori serology in a 70-year-old cohort over 20 years. POPULATION AND METHOD: H. pylori serology at the age of 70 was investigated in 98 men and 132 women born in 1901/02 and in 77 men and 113 women born in 1922. In 21 men and 40 women Helicobacter serology was monitored longitudinally with examinations at 70, 81, and 90 years of age. The analyses were performed on frozen samples by use of an in-house enzyme immunoassay with a sensitivity of 0.99, specificity of 1.00 and positive and negative predictive values of 0.96 and 1.00, respectively. Absorbance values <0.500 were interpreted as negative; values of > or = 0.700 were interpreted as positive, and values in between as inconclusive. RESULTS: The 70-year-old cohort, born in 1922, showed a significantly lower proportion of subjects with positive H. pylori serology in both men (57.1% vs 80.6%) and women (48.7% vs 75.8%) compared with 70-year-olds born in 1901/02. There were no significant sex differences in either cohort. No longitudinal increase or decrease could be demonstrated in those who were examined at 70, 81 and 90 years of age. CONCLUSIONS: The difference in H. pylori prevalence between the two cohorts may reflect a rapid change in socio-economic conditions in Sweden during this 20-year period.     

A non-pungent resiniferatoxin analogue, phorbol 12-phenylacetate 13 acetate 20-homovanillate, reveals vanilloid receptor subtypes on rat trigeminal ganglion neurons

Capsaicin, the vanilloid responsible for the pungent taste of hot peppers, binds to receptors found primarily in polymodal nociceptors. Capsaicin initially stimulates polymodal nociceptors and subsequently inhibits them from responding to a variety of stimuli. This property makes it useful clinically as an analgesic and anti-inflammatory compound. There is mounting, albeit indirect, evidence for the existence of several subtypes of vanilloid receptors. One such piece of evidence comes from studying analogues of capsaicin, such as phorbol 12-phenylacetate 13 acetate 20-homovanillate. This compound binds to (capsaicin) vanilloid receptors on sensory neurons, but unlike capsaicin it is non-pungent and does not produce hypothermia. To determine how sensory neurons respond to phorbol 12-phenylacetate 13 acetate 20-homovanillate, and to compare these responses with those evoked by capsaicin, whole-cell patch-clamp measurements were performed on cultured rat trigeminal ganglion neurons. It was found that 63% of the neurons held at -60 mV were activated by 3 microM, phorbol 12-phenylacetate 13 acetate 20-homovanillate, and 87% of these were also activated by 1 microM capsaicin. In a given neuron, phorbol 12-phenylacetate 13 acetate 20-homovanillate, like capsaicin, could activate kinetically distinct inward currents. The current-voltage curves characterizing phorbol 12-phenylacetate 13 acetate 20-homovanillate responses were asymmetric and had reversal potentials at -5.8 +/- 6.0 mV and 10.4 +/- 4 mV. The averaged dose-response curves for phorbol 12-phenylacetate 13 acetate 20-homovanillate were fit to the Hill equation and had binding constants (K(1/2)s) of 2.73 microM and 0.96 microM and Hill coefficients (ns) of approximately 1 for a rapidly- and slowly-activating current, respectively. These parameters are consistent with those obtained from binding experiments and calcium-influx experiments on sensory nerves. Repeated applications of phorbol 12-phenylacetate 13 acetate 20-homovanillate every 3 min caused a complete reduction in the rapidly-activating currents leaving only a reduced slowly-activating current. This provides strong evidence for the independence of these currents and the existence of subtypes of vanilloid receptors. Additional evidence for the existence of receptor subtypes is that 10 microM capsazepine, a specific and competitive inhibitor of capsaicin-evoked responses, did not inhibit the phorbol 12-phenylacetate 13 acetate 20-homovanillate-induced currents in some neurons and partially inhibited them in other neurons. Thus, there are capsazepine-sensitive and capsazepine-insensitive subtypes of vanilloid receptors. In summary, we have obtained electrophysiological and pharmacological evidence for distinct subtypes of vanilloid receptors.     

Antibiotic therapy for seminal infection. Effect on antioxidant activity and T-helper cytokines

OBJECTIVE: To investigate the effect of antibiotic therapy on seminal infection. STUDY DESIGN: The seminal plasma of 50 men was evaluated in three groups: (1) men with seminal infection (20), (2) men with leukocytospermia only (18), and (3) men of proven fertility (12). The evaluation protocol included semen analysis, culture and antibiotic sensitivity test, total antioxidant activity, alpha-tocopherol and retinol, T-helper cytokines, IL-2, IL-8, IL-4 and antisperm antibodies. RESULTS: Sperm parameters were worse with seminal infection: 25 versus 84 million per milliliter for fertile men. Antioxidant activity, total alpha-tocopherol and retinol were reduced in leukocytospermia (P < .02, .01) and seminal infection (P < .01, .05) as compared to controls. Antisperm antibodies IL-2 and IL-8 were highly expressed, while IL-4 was low in men with leukocytospermia and bacteriospermia. Gram-negative organisms were more associated with expression of T-helper 1 cytokines than T-helper 2 cytokines. Antibiotic therapy significantly improved the sperm parameters, antioxidant activity and IL-4 but reduced IL-2 and IL-8 and had no effect on antisperm antibody titer. CONCLUSION: Antibiotic therapy improves sperm parameters by increasing antioxidant activity and IL-4 and by reducing IL-2 and IL-8.     

Relationship between intraoperative color-flow duplex findings and early restenosis after carotid endarterectomy: a preliminary report

PURPOSE: This study was undertaken to examine the relationship between intraoperative color-flow duplex (CFD) findings and the development of restenosis in patients undergoing carotid endarterectomy (CEA). METHODS: Seventy-eight patients (43 male and 35 female; mean age, 65 years) underwent 86 CEAs (eight staged bilateral) and intraoperative CFD during a 31-month period. Three patients (three CEAs, 3%) underwent both CFD and a completion arteriographic scan. Patients were observed in a postoperative protocol using CFD surveillance. The follow-up interval ranged from 6 to 24 months (average, 12 months). RESULTS: After undergoing CEA, 10 patients (10 CEAs, 11%) had an abnormality detected by intraoperative CFD; one was confirmed with a completion arteriographic scan. These abnormalities consisted of elevated peak systolic velocities (PSV) with a mosaic color pattern suggesting turbulence seen in six CEAs, including one internal carotid artery (ICA) with abnormal hemodynamics and an unremarkable completion arteriogram. Intimal defects on B-mode were seen in another four CEAs. These carotid arteries were reexplored, defects (intimal flaps with platelet thrombus) were confirmed by direct examination, and all were repaired with or without a patch (six ICAs, three external carotid arteries, and one common carotid artery). No cerebrovascular events occurred in the perioperative period. No carotid restenosis (> or = 50% diameter reduction) was identified during follow-up of 43 patients (48 CEAs, 56%). Two patients had recurrent neurologic symptoms. CONCLUSION: Intraoperative CFD is an effective test for detecting flow abnormalities or intimal defects in patients undergoing CEA. Ensuring normal intraoperative hemodynamics after CEA may be a major factor associated with decreased incidence of perioperative cerebrovascular events and subsequent carotid artery restenosis.     

Interleukin-12 and interleukin-18 synergistically induce murine tumor regression which involves inhibition of angiogenesis

The antitumor effect and mechanisms activated by murine IL-12 and IL-18, cytokines that induce IFN-gamma production, were studied using engineered SCK murine mammary carcinoma cells. In syngeneic A/J mice, SCK cells expressing mIL-12 or mIL-18 were less tumorigenic and formed tumors more slowly than control cells. Neither SCK.12 nor SCK.18 cells protected significantly against tumorigenesis by distant SCK cells. However, inoculation of the two cell types together synergistically protected 70% of mice from concurrently injected distant SCK cells and 30% of mice from SCK cells established 3 d earlier. Antibody neutralization studies revealed that the antitumor effects of secreted mIL-12 and mIL-18 required IFN-gamma. Interestingly, half the survivors of SCK.12 and/or SCK.18 cells developed protective immunity suggesting that anti-SCK immunity is unlikely to be responsible for protection. Instead, angiogenesis inhibition, assayed by Matrigel implants, appeared to be a property of both SCK.12 and SCK.18 cells and the two cell types together produced significantly greater systemic inhibition of angiogenesis. This suggests that inhibition of tumor angiogenesis is an important part of the systemic antitumor effect produced by mIL-12 and mIL-18.