Lithiasis of the renal allograft, a rare urological complication following renal transplantation: a single-center experience of 2,045 renal transplantations.

BACKGROUND AND PURPOSE: Urinary lithiasis represents an unusual urologic complication in renal transplantation, with an incidence of 0.17%-1.8%.We present our experience with renal graft lithiasis in our series of renal transplantations. MATERIAL AND METHODS: We reviewed the medical records for 2045 patients who underwent kidney transplantation from January 1983 to July 2013. Among the grafts, 9 patients were found to have allograft lithiasis. In 6 cases, the calculi were localized within the renal unit, and in 3 cases in the ureter. Two of the patients had relapsed after a few years from the first treatment. In both of them the stones were localized again in the ureter. RESULTS: In our series, incidence of graft lithiasis was 0.44% (n = 9). Three of the 9 patients (33.3%) were treated via percutaneous nephrolithotripsy (PCNL), 3 (33.3%) underwent extracorporeal shockwave lithotripsy (ESWL), 2 (22.2%) passed their stones spontaneously, and 1 (11.1%) underwent PCNL after 2 failed ESWL interventions. All patients are currently stone free but still remain under close urologic surveillance. CONCLUSIONS: Urinary stone formation can lead to significant morbidity and graft loss. The treatment options should be similar to those for patients in the general population. Long-term follow-up is substantial to determine the outcome and to prevent the recurrence.

Molecular surveillance of macrolide, tetracycline and quinolone resistance mechanisms in 1191 clinical European Streptococcus pneumoniae isolates.

Streptococcus pneumoniae isolates (n=1191) were collected during a 1997-1999 European surveillance study. In addition to susceptibility data, a molecular epidemiological survey of their mechanisms of resistance to macrolides, tetracyclines, and quinolones was provided. Of the isolates tested, 72.6% were penicillin-susceptible, 19.9% penicillin-intermediate and 7.5% penicillin-resistant. There was an obvious relationship between resistance to penicillin and resistance to erythromycin (19% of all isolates), clindamycin (14%) and tetracycline (23%). Only one isolate was resistant to levofloxacin. Seventy-three percent of the European S. pneumoniae isolates resistant to erythromycin (n=229) carried the erm(B) gene, while the remaining 27% possessed the mef(A) gene. No mutations were detected in 23S rRNA or in ribosomal proteins L4 and L22. All tetracycline-resistant isolates (n=277) carried the tet(M) gene; none carried the tet(O) gene. Classical mutations in gyrA (Ser 81-Phe or Tyr) and parC (Ser 79-Phe and Asp 83-Asn) and efflux contributed to the decreased quinolone susceptibility. This study of recent European S. pneumoniae isolates can be used to recognize any changes in susceptibility patterns and resistance mechanisms that may occur in the future.

Development of resistance to ciprofloxacin, rifampin, and mupirocin in methicillin-susceptible and -resistant Staphylococcus aureus isolates.

A relationship between resistance to methicillin and resistance to fluoroquinolones, rifampin, and mupirocin has been described for Staphylococcus aureus. Differences in resistance rates may be explainable by a higher spontaneous mutation rate (MR) or a faster development of resistance (DIFF) in methicillin-resistant S. aureus (MRSA). No differences in MR, DIFF, and mutations in grlA and gyrA were detected between methicillin-susceptible S. aureus and MRSA. The higher resistance rates in MRSA are not the result of hypermutability of target genes or a faster emergence of different mutations and may be the consequence of clonal spread of multiresistant MRSA.