[Antibiotic resistance of enterococci in Germany]

Treatment of proximal femur infections with antibiotic-loaded cement spacers

In case of periprosthetic hip infections the implantation of antibiotic-loaded PMMA spacers is accepted for an adequate treatment option. Although their indication for the treatment of destructive, bacterial infections of the proximal femur would make sense, literature data are scarce. Hence, the aim of this study was to evaluate the efficacy of antibiotic-impregnated spacers in the treatment of proximal femur infections. In 10 consecutive patients (5 M/ 5 F, mean age 66 y.) with bacterial proximal femur infections, a femoral head/neck resection was prospectively performed with a subsequent implantation of an antibiotic-loaded spacer. The joint-specific outcome was evaluated by the Merle d'Aubigne and the Mayo hip score, the general outcome by SF-36. The time periods were divided into "infection situation", "between stages" and meanly 1 year "after prosthesis implantation". The spacers were meanly implanted over 90 [155-744] days. In all cases an infection eradication could be achieved. After infection eradication, a prosthesis implantation was performed in 8 cases. The general scores showed significant increases at each time period. With regard to the dimension "pain", both scores demonstrated a significant increase between "infection situation" and "between stages", but no significance between "between stages" and "after prosthesis implantation". Spacers could be indicated in the treatment of proximal femur infections. Besides an infection eradication, a pain reduction is also possible.

In vitro evaluation of antibiotic release from and bacteria growth inhibition by antibiotic-loaded acrylic bone cement spacers

The antibiotic release from and the bacteria growth inhibition by antibiotic-loaded acrylic bone cement hip spacers were studied. The cement used was Palacos R, and it was loaded with either one antibiotic powder (gentamicin, vancomycin, teicoplanin, or synercid) [monoantibiotic case] or two antibiotic powders (gentamicin + vancomycin or gentamicin + teicoplanin) [biantibiotic case] and then tested against Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus (MRSA). Antibiotic elution and bacteria growth were measured every 24 h simultaneously by fluorescence polarization immunoassay and photometrically, respectively. The gentamicin + vancomycin combination achieved the longest growth inhibition on S. epidermidis and MRSA (mean of 20 and 14 days, respectively). Gentamicin + teicoplanin-loaded spacers were capable of inhibiting growth on E. faecalis and S. aureus for the longest period (11 and 16 days, respectively). The highest concentrations of gentamicin and vancomycin could be assayed during the first 4 days. Teicoplanin concentrations could be detected only during the first 72 h, synercid was not detected at all, possibly because of the limitation of the detection technique used. A greater percentage of the gentamicin was released than of the vancomycin. The aminoglycosid-glycopeptid combination showed a synergistic effect on the release of gentamicin, but not on vancomycin or teicoplanin. Biantibiotic-impregnated hip spacers proved to be superior to monoantibiotic ones. Because of important differences between the conditions used for the present tests and the in vivo environment, any recommendation with regard to the use of monoantibiotic- and biantibiotic-loaded acrylic bone cement spacers must await the results of further investigations.

MRSA-Infektionen des Bewegungsapparats

INTRODUCTION

We present gentamicin-vancomycin-impregnated beads that can be produced intraoperatively in moulds and demonstrated their successful use in ten cases of problematic Methicillin-resistant Staphylococcus aureus (MRSA) infection.

METHODS

To produce the antibiotically loaded PMMA beads, a two-part mould of polyoxymethylene was used. The mixture of PMMA and antibiotic is poured into the mould halves, and during polymerisation the halves bond together. The in vivo antibiotic concentrations of wound secretion from the redon drainage were measured by fluorescence-polarisation immunoassay, and a concentration/time function was determined. The PMMA beads (2 g of vancomycin plus 0.5 g of gentamicin plus 40 g of PMMA) were implanted in ten patients aged 41-76 years.

RESULTS

In all ten patients, the infection was cured (follow-up 15 months).

CONCLUSION

The combination of gentamicin and vancomycin in the PMMA of standardised beads represents a good alternative in the treatment of MRSA infections. Understanding of the mechanism of antibiotic release from PMMA allows differentiated dosing during systemic application.

Antimicrobial resistance of Enterococci in Lebanon

There is little information on the types of Enterococcus spp and their antibiotic resistance patterns in Lebanon. One hundred and fifty-three consecutive clinical enterococcal isolates collected between 1998 and 1999 were tested against 11 antimicrobial agents using disk diffusion and the Etest. The isolates were identified by conventional methods and API-Strep and were found to consist of Enterococcus faecalis (72.5%), Enterococcus faecium (22.9%), Enterococcus avium (3.2%) and Enterococcus gallinarum (1.3%). The percent of resistant strains of E. faecalis and E. faecium respectively were, ampicillin 0.9 and 14%, erythromycin 59% and 40%, tetracycline 72% and 34%, chloramphenicol 32 and 11%, rifampin 36% and 57%, ciprofloxacin, 23% and 34%, norfloxacin 22 and 8%. High level aminoglycoside (HLA) resistance was found in 19% E. faecalis and 9% E. faecium for gentamicin and 36% and 26% for streptomycin. Excellent correlation was observed between the high level disk tests and the Etest in the detection of HLA resistance but not with the regular disks. None of the isolates showed resistance to vancomycin or teicoplanin except for one E. gallinarum isolate which showed intermediate resistance (MIC 16 mg/l) to vancomycin. These variable antimicrobial rates of resistance suggest a surveillance programme for antimicrobial resistance in this country would be helpful to help control infection, guide empirical antibiotic therapy and implement a policy of antibiotic usage.

Survey of antibiotic resistance among enterococci in North Rhine-Westphalia, Germany

A surveillance study on antibiotic resistance of enterococcal isolates (n = 730) was carried out in North Rhine-Westphalia, Germany, in 1997. Resistance rates to ampicillin (7.4%), high-level gentamicin (15.0%), high-level streptomycin (27.9%), ciprofloxacin (37.9%), vancomycin (1.5%), and teicoplanin (1.5%) were determined. All vancomycin-resistant enterococci (VRE) carried the vanA gene. SmaI and ApaI macrorestriction patterns indicated an intra- and interhospital spread of VRE.

[Febrile neutropenia: practical aspects]

BACKGROUND

Infections are a major cause of mortality in neutropenic patients. They require long hospital stays and highly expensive therapeutic measures. In this review we discuss the practical and pharmaco-economic aspects of the management of febrile neutropenia.

PREVENTION AND THERAPY

Prevention of fever of unknown origin (FUO) demands hygienic and antimicrobiotic measures. First-line antibiotic therapy consists of an aminoglycoside combined with an ureidopenicillin or a 3rd-generation cephalosporin. Double beta-lactam antibiotic combinations are equally effective and less toxic, but more expensive. Monotherapy with carbapenems, ceftazidime, or cefepime appear to offer comparable efficacy. Lung infiltrates require immediate treatment with amphotericin B. If the initial therapeutic regime fails, a carbapenem plus a glycopeptide antibiotic and a parenteral antimycotic drug should be applied after 3 to 4 days. The prophylactic or interventional administration of hematopoietic growth factors is only indicated in special high-risk situations.

CONCLUSIONS

Using the described therapeutic procedure, the response rate exceeds 90%. Consistent, step-wise escalating administration of antibiotics is essential. More evaluation is needed to determine whether selected patients with febrile neutropenia can be treated on an outpatient basis.