Designing fluoroquinolone breakpoints for Streptococcus pneumoniae by using genetics instead of pharmacokinetics-pharmacodynamics

We determined fluoroquinolone microbiological resistance breakpoints for Streptococcus pneumoniae by using genetic instead of pharmacokinetic-pharmacodynamic parameters. The proposed microbiological breakpoints define resistance as the MIC at which >50% of the isolates carry quinolone resistance-determining region mutations and/or, if data are available, when Monte Carlo simulations demonstrate a <90% chance of bacteriological eradication. The proposed microbiological resistant breakpoints are as follows (in micrograms per milliliter): gatifloxacin, >0.25; gemifloxacin, >0.03; levofloxacin, >1; and moxifloxacin, >0.12. Monte Carlo simulations of the once daily 400-mg doses of gatifloxacin and 750-mg doses levofloxacin demonstrated a high level of target attainment (free-drug area under the concentration-time curve from 0 to 24 h/MIC ratio of 30) by using these new genetically derived breakpoints.

Use of a prefabricated tunica vaginalis fascia flap to reconstruct the tunica albuginea after recurrent penile prosthesis extrusion

PURPOSE

Although a penile prosthesis usually perforates into the urethra, it can extrude through the glans or corporeal shaft. Various materials have been used to reconstruct tunica albuginea but no method of repair has been satisfactory in such difficult cases. Repair of the weakened tunica albuginea should ideally be performed with autogenous tissues. Inasmuch as the scarred tissue bed is inadequate to ensure graft survival and no local flaps are available for this purpose, prefabrication of a local flap has been designed.

MATERIALS AND METHODS

We present 2 cases in which the distal corpus was reconstructed with a prefabricated tunica vaginalis fascia flap. The first stage involves grafting rectus fascia onto the external tunica vaginalis of the testicle. At the second stage the prefabricated tunica vaginalis fascia flap is transposed to the distal corpus, placing it as a buttress between the cylinder and urethra medially or between the cylinder and thin lateral and distal tunica albuginea. The flap also replaces part of the tunica albuginea.

RESULTS

In both patients repair of the tunica albuginea was successful and each has a functioning inflatable penile prosthesis at 2 1/2 1 1/2 years postoperatively, respectively.

CONCLUSIONS

Reconstruction of the weak tunica albuginea with a prefabricated tunica vaginalis fascia flap is an excellent procedure in these difficult cases.