Long-term results after acute therapy of obstructive pyelonephritis.

INTRODUCTION: To evaluate therapeutic results till 5 years after therapy of obstructive pyelonephritis (OPN) emphasizing regular follow-up. MATERIAL AND METHODS: During 5 years, 57 patients with OPN were treated. The patients' charts were reviewed retrospectively for clinical data. These were completed by a questionnaire. RESULTS: In the group of 57 patients (average age 56 years), about two third were women. Urolithiasis (65%) and tumors (21%) were the main causes of obstruction; fever (91%) and loin pain (86%) the main symptoms. Three fourth of the patients showed renal insufficiency and nearly 50% anemia. E. coli and Proteus spp. were the dominating organisms. Sonography detected obstruction in 93% cases. In one third of cases, CT scan was added; 81% percutaneous nephrostomy and 19% ureteral stenting were the initial methods of urinary drainage. During therapy, 23% nephrectomies (19% complete, 4% partial) were performed. Long-term follow-up showed 11% recurrent OPN and 33% recurrent UTI. CONCLUSIONS: After diagnosis of OPN, primary nephrostomy or ureteral stenting and antibiotic therapy are the first measures. If recurrent urinary tract infections or OPN occur, long-term follow-up and low-dose antibiotic prophylaxis may be discussed.

In-vitro analysis of the effect of gentamicin and polyhexanide on bone tissue.

PURPOSE: Though anti-infectives have been used for a long time in surgical procedures, the effect on bone tissue has not been determined for most antibiotics and antiseptics. METHODS: In our in vitro study, 4x4x8 mm(3) blocks of rabbit cancellous bone tissue were incubated with Ringer's solution, gentamicin and Lavasorb(®) each for time intervals of 15 minutes, 30 minutes, one hour, four hours and eight hours. Samples were examined double blinded through optical and electron microscopy. RESULTS: Tissue degeneration was observed in all samples. It was low in Ringer's solution. Samples with Lavasorb showed a moderate degeneration after 15 and 30 minutes, which was accelerated after one hour. Gentamicin led to a moderate degeneration of bone tissue after 15 and 30 minutes and to a more accelerated degeneration after one hour. The effect of gentamicin on bone tissue was more pronounced than the effect of Lavasorb. CONCLUSIONS: This investigation showed that local application of Lavasorb or gentamicin on bone tissue should be restricted to 30 minutes, while Lavasorb showed a better tissue tolerability. This finding could have clinical implications for the management of wounds with open osseous tissue and should be further investigated by in vivo studies.

Bacterial decontamination of surgical wounds treated with Lavasept.

In a prospective randomized controlled double-blind study in 50 acutely injured patients, bacterially contaminated type 2-4 soft tissue wounds were treated with moist dressings of 0.2% Lavasept (fractionated polyhexamethylenbiguanide and macrogolum 4000) solution (n=28) in comparison with Ringer solution (n=22). Standardized swabs were taken on days 0, 2, 8 and 15 and investigated for microorganisms. For a quantitative evaluation, the number of colony forming units (CFU) was determined by a serial dilution technique. The tissue compatibility and anti-inflammatory effect were rated on a scale of 0 (=bad) to 3 (=very good). The most frequently found microorganism was Staphylococcus aureus, which was isolated from 13 wounds. Use of Lavasept led to a faster and significant reduction in microorganisms on the wound surfaces. The number of CFU per wound remained constant or decreased, in contrast to the wounds treated with Ringer solution. This was true for both Gram-positive and Gram-negative bacteria. There was no evidence of impaired wound healing in either group. The anti-inflammatory effect and the tissue compatibility of Lavasept were rated significantly better than that of Ringer solution. It is concluded that Lavasept combines antiseptic action with good tissue compatibility.

Activity of the antiseptic polyhexanide against gram-negative bacteria.

The activity of the antiseptic polyhexanide was tested against 250 gram-negative clinical isolates, that is, 50 isolates each of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Moraxella catarrhalis, and Haemophilus influenzae. Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) were determined by using a serial broth microdilution technique according to DIN 58940. Time-kill studies were performed for reference stains E. coli ATCC 25922, K. pneumoniae ATCC 4352, P. aeruginosa ATCC 15442, M. catarrhalis ATCC 43617, and H. influenzae ATCC 49247. All tested isolates had MICs and MBCs within a range of 1-32 mg/L and were regarded as susceptible to polyhexanide. The highest values were found for P. aeruginosa and H. influenzae with MICs and MBCs of 32 mg/L. Addition of up to 4% albumin to the test medium did not change MICs and MBCs. Time-kill studies of the reference strains showed reduction rates from 3 log10 colony forming units (CFU)/ml to more than 5 log10 CFU/ml for 200 and 400 mg/L polyhexanide within 5-30 min. Testing of polyhexanide in combination with antibiotics showed indifference with amoxicillin, cefotaxime, imipenem, gentamicin, and ciprofloxacin; no antagonism was found. As no resistance and no antagonism with antibiotics were detected, polyhexanide is regarded as suitable agent for topical eradication of gram-negative bacteria.

Inhibition of the anti-staphylococcal activity of the antiseptic polihexanide by mucin.

The antiseptic Lavasept (LS), containing the polymeric biguanide polihexanide (CAS 28757-48-4), possesses microbicidal activity against a broad spectrum of bacteria including Staphylococcus aureus. It is used for antiseptic wound care in concentrations corresponding to 0.2-0.4 mg polihexanide per ml. To obtain basic data on its ability to eradicate S. aureus colonizing the nasal mucosa, the influence of mucin on the anti-staphylococcal activity was investigated. A disk agar-diffusion method was applied. Two reference strains of S. aureus (methicillin-sensitive S. aureus ATCC 29213 and methicillin-resistant S. aureus ATCC 33591) and 20 fresh clinical isolates were used. In the absence of mucin, the growth of all strains was inhibited by polihexanide concentrations of 0.1 mg/ml. In the presence of 0.25% mucin in the test medium, a concentration of 0.4 mg/ml was necessary to inhibit all strains. Mucin concentrations of 0.5% and 1%, that are even lower than the mucin concentrations in healthy nasal secretions, abolished the activity of the therapeutic concentrations of polihexanide. It is concluded that the inactivation of LS by mucin obstructs a reliable clearance of nasal S. aureus carriage.

Influence of mucin on the activity of the antiseptic Lavasept against Staphylococcus aureus.

BACKGROUND: Lavasept, containing the polymeric biguanide polyhexanide, may be effective against Staphylococcus aureus colonizing the nasal mucosa. To obtain basic data on its suitability for that purpose, its antimicrobial activity was examined in the presence of mucin. METHODS: A disk diffusion test was applied using Mueller-Hinton agar, and disks soaked with a therapeutic and a 10-fold higher concentration of Lavasept. Commercially available mucin preparations from porcine stomach were added to the test system. Reference strains and 20 clinically isolates of S. aureus, and reference strains of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans were tested. RESULTS: Supplementation of the test medium with 1% mucin completely abolished the activity of disks loaded with the therapeutically used concentration of the antiseptic. The neutralizing effect of mucin occurred with all test strains. CONCLUSIONS: The inactivation of Lavasept by mucin may hamper a reliable clearance of nasal S. aureus carriage.