Quantitation and relative distribution of extracellular matrix in Staphylococcus epidermidis biofilm

The relationship between adherence of bacteria to foreign bodies and their deposition of extracellular matrix was examined on glass and suture material. To quantitate bacterial adherence, uptake of [3H]thymidine into bacterial DNA was analyzed. Corresponding amounts of extracellular matrix were measured by a new technique using [14C]glucose incorporation. This study shows that [14C]glucose preferentially labeled bacterial strains in proportion to biofilm production. The ratio of 3H14C in high biofilm producers was 0.9 and in low producers it was 3.7. Radioactive identification of organisms as high and low producers was confirmed by electron microscopy. The results presented here show that production and accumulation of biofilm over time is a stable characteristic in different strains of S. epidermidis. The use of ratios reflecting radiolabeling of bacteria and biofilm by [3H]thymidine and [14C]glucose, respectively, is a quantitative yet simple technique to assess extracellular matrix of different strains of S. epidermidis.     

Experimental treatment of vascular graft infection due to Staphylococcus epidermidis by in situ replacement with a rifampin-bonded polyester graft

In situ prosthetic graft replacement (ISPGR) of an infected prosthesis raises the risk of recurrent infection in the new graft, especially in cases involving drug-resistant microorganisms. The purpose of this animal study was to evaluate in situ replacement of a vascular graft infected by a highly rifampin-resistant strain of Staphylococcus epidermidis with the use of a rifampin-bonded polyester graft. Antibiotic bonding was obtained by soaking grafts in a high dose of rifampin solution (60 mg/mL). The infrarenal abdominal aorta of 20 dogs was replaced using a polyester prosthesis infected with a highly rifampin-resistant strain of Staphylococcus epidermidis. One week later, the 18 surviving animals were randomized into three groups. Group I (n = 6) did not undergo reoperation. Group II (n = 6) underwent ISPGR using a rifampin-bonded prosthesis. Group III (n = 6) underwent ISPGR using an untreated prosthesis. All surviving animals were killed 28 days after the first procedure. Infectious signs were noted and bacteriological study was carried out on explanted prostheses and various tissue samples. The findings of this experimental study show that soaking a polyester prosthesis in a high-dose rifampin solution can prevent reinfection after in situ replacement of a prosthesis infected by a highly rifampin-resistant Staphylococcus epidermidis.     

A rat model of polypropylene graft infection caused by Staphylococcus epidermidis

BACKGROUND: The aim of this study was to constitute a valid graft infection model with Staphylococcus epidermidis in rats. METHODS: Rats were divided into seven groups. In groups 1 and 2, 2 cm x 2 cm polypropylene grafts were incubated with 10(8) c.f.u./mL slime-positive S. epidermidis at 37 degrees C for 2 and 24 h and were then placed subfascially to the groins of rats. In the third group, naive grafts were placed and 0.5 mL of 3 x 10(7) c.f.u. slime-positive S. epidermidis were injected on the inside of the wounds. Rifampicin (30 mg/kg) in group 4 and teicoplanin (20 mg/kg) in group 5 were applied i.p. to rats with 2-h incubated grafts for prophylaxis. The same prophylactic regimens were given to groups 6 and 7 in which rats were incubated for 24 h. At eighth day, rats were killed and wounds were assessed with macroscopic evaluation and cultures. RESULTS: No death occurred in any of the groups. In groups 1 and 2, 100% infection rates were achieved. However, graft infection was detected in only two (20%) of the rats in group 3 (P = 0.001). Prophylactic application of teicoplanin or rifampicin decreased the infection rates significantly in the short-incubation groups. CONCLUSION: Incubation of polypropylene grafts with slime-producing S. epidermidis for 2 and 24 h in the pre-application period achieved the occurrence of a standardized graft infection. Prophylactic use of teicoplanin and rifampicin decreased the infection rates. We propose to use this reproducible and reliable animal model of graft infection in future studies.     

245. Problemkeim Staphylococcus epidermidis in der Implantatchirurgie

Zusammenfassung In einer klinischen Studie der postoperativen Infektionen nach Metallimplantationen und PmmA Einbringung wurde gezeigt, daß Staphylococcus epidermidis sich zum Problemkeim zu entwickeln scheint. 50% der postoperativen Infektionen nach Implantateinbringung wurden durch diesen Keim verursacht. Die Resistenzentwicklung dieses Keimes unter Antibioticatherapie wird anhand von MIC und MBC dargestellt.     

Crescentic glomerulonephritis associated with totally implantable central venous catheter-related Staphylococcus epidermidis infection

A 59-year-old woman was admitted to our hospital for treatment of acute renal insufficiency. She had been under home intravenous hyperalimentation therapy through a totally implantable central venous catheter for 2 years because of post-radiation enteritis. Clinical examination on admission revealed severe renal insufficiency complicated with hypocomplementemia, marked proteinuria and hematuria. Chest roentgenography demonstrated moderate pulmonary congestion. Hemodialysis was initiated and her pulmonary congestion improved. On the 14th and 21st hospital day, blood culture revealed Staphylococcus epidermidis colonization. Cefazolin was administered and C-reactive protein decreased, however, renal insufficiency and hypocomplementemia did not improve. To investigate the genesis of renal insufficiency, renal biopsy was performed. Light microscopic findings of the kidney revealed severe crescentic glomerulonephritis complicated with moderate tubulointerstitial damage. Immunofluorescence-microscopic findings of the kidney revealed positive IgG, IgM, C3 deposition along the capillary lumen. From these laboratory findings and the clinical course, we diagnosed her renal disease as crescentic glomerulonephritis induced by catheter-related bloodstream infection, and the central venous catheter was removed. After removal, urinary output and hypocomplementemia remarkably improved, however, unfortunately, her renal dysfunction did not improve and maintenance hemodialysis needed to be continued. Although her renal disease was not caused by ventriculo-atrial shunt but by central venous catheter-related bloodstream infection, we supposed that the pathogenesis was a closely similar entity to shunt nephritis.     

Quinupristin/dalfopristin bonding in combination with intraperitoneal antibiotics prevent infection of knitted polyester graft material in a subcutaneous rat pouch model infected with resistant Staphylococcus epidermidis.

OBJECTIVE: to investigate the efficacy of quinupristin/dalfopristin in the prevention of prosthetic graft infection in a rat subcutaneous pouch model. METHODS: graft infections were established in the subcutaneous tissue of 140 male Wistar rats by implantation of Dacron prostheses followed by topical inoculation with Staphylococcus epidermidis with intermediate resistance to glycopeptides. The study included one group without contamination, one contaminated group without prophylaxis, one contaminated group that received 50mg/l quinupristin/dalfopristin-soaked graft, one contaminated group that received 10mg/kg intraperitoneal levofloxacin, one contaminated group that received 3mg/kg intraperitoneal doxycycline, and two contaminated groups that received 50mg/l quinupristin/dalfopristin-soaked plus 10mg/kg intraperitoneal levofloxacin or 3mg/kg intraperitoneal doxycycline. Each group included 20 animals. The grafts were removed after 7 days and evaluated by quantitative culture. RESULTS: quinupristin/dalfopristin showed a significantly higher efficacy than levofloxacin and doxycycline, even though quantitative graft cultures for rats that received only quinupristin/dalfopristin-soaked graft showed bacterial growth. Otherwise, the efficacy of levofloxacin was similar to that of doxycycline. Only the group treated with quinupristin/dalfopristin combined with levofloxacin or doxycycline showed no evidence of staphylococcal infection. CONCLUSIONS: quinupristin/dalfopristin as adjunctive topical antibiotic prophylaxis can be useful for the prevention of vascular graft infections caused by staphylococcal strains with high levels of resistance.     

EPA covalently bound to smooth titanium surfaces decreases viability and biofilm formation of Staphylococcus epidermidis in vitro

Colonization of implant surfaces with bacteria should ideally be prevented right from implantation, as bacteria attaching to the surface will form a biofilm, being then well protected against antibiotic treatment. Therefore, implant coatings should combine antibacterial properties with biocompatibility towards their host tissue. We tested a UV‐induced covalent coating procedure with eicosapentaenoic acid (EPA) for smooth titanium (Ti) surfaces for its ability to prevent attachment and proliferation of Staphylococcus epidermidis and to allow mineralization of MC3T3‐E1 osteoblasts. Bacterial initial attachment was highest for EPA‐coated surfaces, but was reduced by vigorous washing, possibly due to low adhesive strength on those surfaces. We found an increase in the ratio of dead bacteria and in overall biofilm after 16 h on Ti surfaces with covalently bound EPA compared to Ti. The UV‐induced EPA coating did not impair the ability of MC3T3‐E1 preosteoblasts to mineralize, while a reduction in mineralization could be found for UV‐irradiated Ti surfaces and UV‐irradiated surfaces washed with ethanol compared to Ti. Although in vivo studies are needed to evaluate the clinical significance, our results indicate that covalent coating of Ti surfaces with EPA by UV irradiation decreases the survival of S. epidermidis and maintains the mineralization ability of osteoblasts. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1384–1390, 2012     

Vascular prosthetic infection with Staphylococcus epidermidis: experimental study of pathogenesis and therapy

To determine whether a slime-producing strain of Staphylococcus epidermidis was capable of producing acute infection of a prosthetic vascular graft, 5 cm segments of knitted Dacron were implanted in the infrarenal aortic position of dogs in three groups of animals. These included a control group (no graft contamination), a contaminated group that received a graft soaked in an S. epidermidis solution (untreated group), and a contaminated group in which perioperative antibiotics (three doses of cefamandole, 100 mg/kg) were administered (prophylaxis group). In all the animals reexploration and graft removal were performed at 10 days, with replacement of the defect being achieved with a new uncontaminated graft. These animals underwent exploration a third time after an additional 10-day period. S. epidermidis was not grown from the control animals (n = 7) but was cultured in 44% of the prophylaxis group (n = 9) and 88% of the untreated group (n = 16) during at least one of the operative procedures (chi 2 = 15.859; p less than 0.001). The pathologic features of acute S. epidermidis infection were best seen in the untreated animals and included anastomotic disruption (56%), periaortic hematoma, and lymphadenopathy (94%). Microscopic examination of the aortic tissues revealed extensive infiltrates of leukocytes, macrophages, and foreign body giant cells with aortic necrosis. These features were less prominent in the prophylaxis animals. We conclude that S. epidermidis is capable of producing acute graft infection with perigraft inflammation and anastomotic disruption. The administration of perioperative antibiotics reduced but did not abolish these effects of bacterial contamination of prosthetic vascular grafts.     

Gelatin-sealed dacron graft is not more susceptible to MRSA infection than PTFE graft.

OBJECTIVES: The purpose of this experimental study was to compare the susceptibility of gelatin-sealed Dacron and PTFE prostheses to infection by MRSA. DESIGN: Prospective, randomized, controlled animal study. MATERIALS AND METHODS: Graft infections were established in the subcutaneous tissues of 60 female Spraque-Dawley rats by the implantation of gelatin-sealed Dacron or PTFE prostheses followed by topical inoculation with methicillin-resistant Staphylococcus aureus. The study groups were as follows: (1A) uncontaminated gelatin-sealed Dacron group, (1B) untreated contaminated gelatin-sealed Dacron group, (1C) contaminated gelatin-sealed Dacron group with intraperitoneal teicoplanin treatment, (2A) uncontaminated PTFE group, (2B) untreated contaminated PTFE group, and (2C) contaminated PTFE group with intraperitoneal teicoplanin treatment. The grafts were removed after 7 days and evaluated for infection by counting the number of adherent bacteria on the graft material after rinsing and sonication. The perigraft tissue was harvested for histopathological study. To investigate the existence of any infection, blood samples were collected by cardiopuncture for a culture analysis. RESULTS: No significant difference in bacteria counts was observed between gelatin-sealed Dacron and PTFE grafts. In groups 1A and 2A, there was no infection detected. The bacterial counts for MRSA were 7.4 x 10(5) in group 1B and 8.6 x 10(5) in group 2B. There was also no infection in groups 1C and 2C. While the difference between group 1B and 2B was not significant (p>.05), bacterial counts in group 1B or 2B were significantly higher than those in other groups. Blood cultures were only positive in four rats in group 1B and in two rats in group 2B. The severities of the inflammation of the perigraft tissues was low in groups 1A and 2A, high in groups 1C and 2C, and between the range from low to moderate in groups 1B and 2B. CONCLUSION: The susceptibility of gelatin-sealed Dacron to bacterial infection was not higher than that of PTFE.     

Staphylococcus epidermidis sepsis in surgical patients

We examined 58 surgical patients with two or more blood cultures positive for Staphylococcus epidermidis to determine factors associated with risk, mortality, and invasive sepsis. Bacterial sepsis was associated with gastrointestinal (GI) operations, total parenteral nutrition, and a regimen of two or more parenteral antibiotics. Mortality was 46% overall and significantly increased with age greater than 50 years, GI operations, other gram-positive sepsis, recurrent sepsis (positive blood culture 24 hours or more after the first blood culture), and the presence of organisms sensitive to three or less antibiotics. Antibiotic therapy appropriate for more than 50% of the S epidermidis organisms cultured from each patient resulted in significant reduction in mortality. Staphylococcus epidermidis should be considered a significant pathogen in critically ill surgical patients. Invasive S epidermidis sepsis can be recognized and requires specific antibiotic therapy.     

Staphylococcus epidermidis in diabetic urological patient

We present 6 patients in whom prosthetic failure occurred because of sepsis owing to Staphylococcus epidermidis. Such failure occurs in grafts in other areas and is caused by the high resistance of the organism to conventional antibacterial measures. Therapy with appropriate antibiotics, that is aminoglycosides, vancomycin and rifampin, and the need for an early operation are stressed.     

Affinity of Staphylococcus epidermidis to various prosthetic graft materials.

BACKGROUND: Abdominal wall hernias have always been a major problem for general surgeons. The techniques of repairing primary, recurrent, and incisional hernias have evolved throughout the years at an accelerating trend, especially after production of prosthetic graft materials. Although looked upon with suspicion due to infection, fistula formation, and foreign body reaction, prosthetic graft materials are used deliberately in primary and recurrent hernias. The present study was designed to evaluate bacterial adherence to frequently used prosthetic graft materials. MATERIALS AND METHODS: The study was carried out in five different groups with each group consisting of 10 identical samples of the same kind of prosthetic graft material. The prosthetic graft materials used in the study were polypropylene, polyglactin 910, polyester fibers, steel, and polytetrafluoroethylene (PTFE). These prosthetic graft materials were incubated in vitro with a Staphylococcus epidermidis strain which was ++++ adhesion positive. The degree of adhesion of S. epidermidis to prosthetic graft materials was assessed by the ELISA method. RESULTS: Vicryl grafts showed significantly minimal bacterial adhesion whereas PTFE grafts tended to have more adhesion but this did not reach a statistical significance. Other graft materials did not show any difference for bacterial adhesion (Table 3). CONCLUSION: These results suggest that in vitro S. epidermidis adhesion to Vicryl grafts is less than other types of prosthetic graft materials (P < 0.05 for all comparisons). Further in vitro and in vivo studies are required to confirm these results and to understand the complex interactions among bacteria, graft material, microenvironment, and surgical technique.     

Linezolid alone and in combination with rifampicin prevents experimental vascular graft infection due to methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis

BACKGROUND: In this report we describe the in vivo antibacterial activity of linezolid in an experimental graft infection model in rats and compare it with teicoplanin. The objective of this study was also to determine the effects of the interaction of linezolid when it was combined with rifampicin and test this effect against strains of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. MATERIALS AND METHODS: Graft infections were established in the subcutaneous tissue of 130 Wistar rats by implantation of Dacron grafts followed by a topical inoculation with 2 x 10(7) CFU of clinical isolates of MRSA and MRSE. The study included a control group and six groups for each of the staphylococcal strains: an inoculated group that did not receive any antibiotic prophylaxis, two inoculated groups that received intraperitoneal prophylaxis with teicoplanin or linezolid alone, an inoculated group that received rifampicin-soaked grafts, and two inoculated groups that received a combination prophylaxis consisting of intraperitoneal teicoplanin or linezolid and rifampicin-soaked grafts. RESULTS: There was a reduction in the quantitative bacterial graft cultures in all prophylaxis groups when compared with inoculated control groups. There was not a statistically significant difference between linezolid and teicoplanin prophylaxis groups. The best results were obtained by a combination of rifampicin-soaked grafts with linezolid or teicoplanin. CONCLUSIONS: We found no evidence to suggest that linezolid differs from teicoplanin regarding effectiveness in the prevention of prosthetic vascular graft infection. Linezolid plus rifampicin and teicoplanin plus rifampicin are demonstrated to be valuable prophylactic regimens.     

表皮葡萄球菌生物膜蛋白在假体周围感染诊断中的应用

目的探讨表皮葡萄球菌生物膜蛋白作为抗原诊断假体周围感染的临床价值。方法制作表皮葡萄球菌感染的假体周围感染动物模型，并收集临床假体周围感染患者的血清。以从表皮葡萄球菌444生物膜中提取的蛋白为抗原，用ELISA方法检测感染动物和临床假体周围感染患者的血清中IgG水平。蛋白印迹杂交寻找特异性抗原蛋白。结果感染动物和感染患者血清中的IgG水平明显高于各自对照组，Western—blot结果显示，表皮葡萄球菌生物膜蛋白大小在15KD-37KD之间具有良好的抗原性。结论表皮葡萄球菌生物膜蛋白成份具有良好的抗原性，是引起机体免疫的重要成份。进一步纯化这些蛋白组分并作为诊断假体周围表皮葡萄球菌感染的抗原，具有重要的临床价值。