Bacterial and fungal infections in the early post-transplant period after kidney transplantation: etiological agents and their susceptibility

BACKGROUND

Infections remain serious complications in solid-organ transplant recipients, despite professional medical care, the introduction of new immunosuppressive drugs, and treatment that decreases the risk of infections.

METHODS

The study covered 295 adult patients undergoing kidney transplantation (KTx) between September 2001 and December 2007. All the patients were followed prospectively for infections from the KTx date and during the first 4 weeks after surgery. Samples of clinical materials were investigated for microbiological cultures. The microorganisms were cultured and identified in accordance with standard bacteriological procedures. Susceptibility testing was carried out through the use of Clinical and Laboratory Standards Institute procedures.

RESULTS

From 295 KTx recipients, 1073 clinical samples were taken for microbiological examination. Positive cultures were 26.9% (n = 289) of all samples tested; 525 strains were collected. Gram-positive bacteria were isolated in 52.2% (n = 274), Gram-negative bacteria were isolated in 40.8% (n = 214), and fungal strains were isolated in 7% (n = 37). Urine specimens (n = 582) were obtained from 84.5% of 245 recipients during the first month after transplantation. Among the isolated bacterial strains (n = 291), the most common were Gram-negative bacteria (56.4%). Gram-positive bacteria comprised 35.7%; fungal strains were found in 23 cases (7.9%). In surgical site specimens (n = 309), Gram-positive bacteria (72.1%) were the most common. Gram-negative bacteria comprised 24.4%. In blood specimens (n = 138), Gram-positive bacteria (81.6%) were the most common. Gram-negative bacteria comprised 15.8%; fungi were isolated in 2.6%. In respiratory tract specimens (n = 13), among the isolated bacterial strains (n = 8), the most common were Gram-positive bacteria (57.1%). Gram-negative bacteria comprised 14.3%; fungi were isolated in 28.6%.

CONCLUSIONS

Urine samples were predominantly positive after KTx. Our study showed Gram-positive bacteria in 52.2% after kidney transplantation. The proportion of isolates of multi-drug-resistant bacterial strains (MRCNS, vancomycin-resistant strains, high-level aminoglycoside-resistant strains, extended-spectrum beta-lactamase producers, and high-level aminoglycoside-resistant strains) was increased. These data indicate the need for strict adherence to infection control procedures in these patients.

Impact of pretransplant body mass index on early kidney graft function

BACKGROUND

An increase in the number of obese patients on transplantation waiting lists can be observed. There are conflicting results regarding the influence of body mass index (BMI) on graft function.

METHODS

We performed a single-center, retrospective study of 859 adult patients who received a renal graft from deceased donors. BMI (kg/m(2)) was calculated from patients' height and weight at the time of transplantation. Kidney recipients were subgrouped into 4 groups, according to their BMI: Groups A (<18.5; n = 57), B (18.6-24.9; n = 565), C (25-29.9; n = 198) and D (>30; n = 39). Primary or delayed graft function (DGF), acute rejection (AR) episodes, and number of reoperations, graft function expressed by glomerular filtration rate (GFR) and serum creatinine concentration and number of graft loss as well as the recipient's death were analyzed. The follow-up period was 1 year.

RESULTS

Obese patients' grafts do not develop any function more frequently in comparison with their nonobese counterparts (P < .0001; odds ratio [OR], 32.364; 95% CI, 2.174-941.422). Other aspects of the procedure were analyzed to confirm that thesis: Cold ischemia time and number of HLA mismatches affect the frequency of AR (OR, 1.0182 [P = .0029] and OR, 1.1496 [P = .0147], respectively); moreover, donor median creatinine serum concentration (P = .00004) and cold ischemia time (P = .00019) are related to delayed graft function. BMI did not influence the incidence of DGF (P = .08, OR; 1.167; 95% CI, 0.562-2.409), the number of AR episodes (P > .1; OR, 1.745; 95% CI, 0.846-3.575), number of reoperations, GFR (P = .22-.92), or creatinine concentration (P = .09). Number of graft losses (P = .12; OR, 1.8; 95% CI, 0.770-4.184) or patient deaths (P = .216; OR, 3.69; 95% CI, 0.153-36.444) were not influenced.

CONCLUSION

Greater recipient BMI at the time of transplantation has a significant influence on the incidence of primary graft failure.

Bacterial and fungal infections in the early post-transplantation period after simultaneous pancreas-kidney transplantation: etiological agents and their susceptibility

OBJECTIVE

This study aims to evaluate the frequency of microbial isolates and their susceptibility profiles cultured from clinical samples obtained from 26 simultaneous pancreas-kidney transplant (SPK) recipients suspected of infections during the early post-transplantation period.

PATIENTS AND METHODS

Data on microbiologic culture of 26 adult patients undergoing SPK were collected prospectively from 2001 to the end of 2006. Isolation and identification of cultured micro-organisms were performed according to standard microbiological procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was made by the Clinical and Laboratory Standards Institute guidelines.

RESULTS

All the patients were followed prospectively for the first 4 weeks after surgery. In total, 263 samples from clinical materials obtained from 26 SPK recipients were cultured. Bacterial cultures were positive in 29.3% (n = 77) clinical samples. Of these, 219 microbial strains were cultured. Gram-positive bacteria were found in 64% (n = 140), Gram-negative bacteria in 22.8% (n = 50), and fungal strains were isolated in 13.2% (n = 29). Incidence rate values for subsequent isolation of micro-organisms in the sub-periods of time for decreasing the SPK were Gram-positive bacteria (102.3-18.7; I versus IV), growing the Gram-negative bacteria (14-46.1 I versus III) IV were 14, decreasing to fungi (22.1-1.6, I versus IV). Until now this early post-transplantation period was considered homogeneous time after transplantation. This study shows that this period is actually heterogenous, with statistically significant differences being observed between results obtained in consecutive 4 weeks after transplantation.

CONCLUSIONS

The results of this study show that the incidence rate was elevated with increasing age in the SPK group of patients. In the SPK group, our data showed the highest rate of isolation of micro-organisms compared with recipients of kidneys or liver.

Characteristics of potential living kidney donors and recipients: donor disqualification reasons--experience of a Polish center

INTRODUCTION

Kidney transplantation is efficacious as a renal replacement, particularly pre-emptive living donation. In Poland, the rate of transplantation of living donor kidneys is only 3%. The aim of the study was to identify the most common reasons to disqualify a potential living kidney donor.

METHODS

We evaluated 124 kidney donor candidates for 111 potential recipients at 1 medical center for genders and ages of donor and recipient; thus relation, donor disqualification reasons, number of potential donors for a particular recipient, prior transplantations, and kidney vasculature.

RESULTS

The 111 recipients of ages 2-62 years had, 1, 2, or 3 potential donors were tested in 101, 1, and 7, cases respectively. We had 18.9% recipients referred for pre-emptive transplantation; 59.5% were on haemodialysis and 21.6% on peritoneal dialysis. In all, 89% recipients sought first kidney transplantations. Kidneys were procured from 49/124 (39.5%) of the initially evaluated donors. The full examination was completed by 92 potential donors with 68/124 donors disqualified early. Single and multiple renal arteries were detected in 56 and 36 potential donors, respectively. Donor disqualification was due to medical contraindications (39.7%), earlier transplantation from a deceased donor (25%), immunologic constraints (23.5%), donor consent withdrawn (6%) or psychological and social reasons (4.4%).

CONCLUSIONS

A considerable number of donor candidates are disqualified for medical reasons.

Uridine diphosphate glucuronosyltransferase 2B7 variant p.His268Tyr as a predictor of kidney allograft early acute rejection

BACKGROUND

Uridine diphosphate glucuronosyltransferase (UGT2B7) is responsible for conversion of mycophenolic acid to mycophenolic acyl-glucuronide (acylMPAG). Conflicting data exist regarding the role of UGT2B7 p.His268Tyr (802C>T, rs7439366) variant in the clinical course following organ transplantation.

STUDY AIM

The aim of this study was to reveal an association between UGT2B7 p.His268Tyr (802C>T, rs7439366) polymorphism and kidney transplantation outcome. STUDY DESIGN, PATIENTS, AND METHOD: Genomic DNA of 235 kidney transplant recipients was genotyped for UGT2B7 802C>T using TagMan single nucleotide polymorphism (SNP) genotyping assay. Maintenance immunosuppression used mycophenolate mofetil (MMF) and cyclosporine A (n = 137) or tacrolimus (n = 98). Primary end-point was biopsy-confirmed acute rejection within 3 and 12 post-transplantation months. Secondary end-points included gastrointestinal side effects, leukopenia, lymphopenia, neutropenia, and infections. Statistical analysis was performed with the aid of SAS System using kernel-smoothed estimates of acute graft rejection hazard function. The log-rank test and hazard ratio were used to reflect association between UGT2B7 802C>T variant and risk of acute graft rejection.

RESULTS

Within 3 postimplantation months 38 (16.2%) patients experienced acute rejection; 33 were allele C carriers in UGT2B7 802C>T SNP and 5 were TT homozygotes (P < .0457). Allele C-associated risk of rejection was 2.50 and remained between 2.19 and 3.02 after adjustment for clinical confounders, ie, HLA mismatch, panel-reactive antibodies, donor age, repeated transplantation, induction therapy, donor type, delayed graft function, applied calcineurin inhibitor, or MMF dosing. We found no association between the polymorphism and gastrointestinal side effects, leukopenia, lymphopenia, neutropenia, and infections.

CONCLUSION

UGT2B7 802C>T genotyping may help identify patients with excessive early acute rejection risk.

Herpes encephalitis during natalizumab treatment in multiple sclerosis

In this case report we describe the first non-fatal herpes simplex virus encephalitis (HSE) case with natalizumab for multiple sclerosis (MS). A 36-year-old woman, previously treated with immunomodulatory and immunosuppressive drugs for MS, developed acute encephalitis after 6 monthly natalizumab perfusions. Brain imaging demonstrated suggestive bi-temporal lesions. Herpes simplex virus type-1 DNA was detected in cerebrospinal fluid. The patient improved gradually after a 21-day course of intravenous acyclovir, but neuropsychiatric changes remained 5 months later. Our non-fatal case of HSE and other reported cases of herpes infections provide evidence of an increased risk with natalizumab and point to the need for clinicians to maintain awareness.

Complications of transplantation of kidneys from expanded-criteria donors

BACKGROUND

Organ shortage is the primary barrier to kidney transplantation. To maximize organ use, organs from expanded-criteria donors (ECDs) have been used increasingly. Expanded-criteria donors are defined as individuals older than 60 years or older than 50 years with at least 2 of the following risk factors: hypertension, stroke as the cause of death, or serum creatinine concentration greater than 1.5 mg/dL.

OBJECTIVE

To assess the incidence of complications posttransplantation in ECD kidneys compared with kidneys from standard-criteria cadaveric donors (SCDs).

PATIENTS AND METHODS

One hundred seventy-two patients received cadaveric renal transplants between January 1, 2006, and August 31, 2008. Donor and recipient data were collected, as well as patient and graft survival and immediate, delayed, or slow graft function. Complication rates for lymphocele, urinary leak, thrombosis, hematoma, urinary tract infection, and cytomegalovirus infection were recorded. Follow-up was for 3 to 35 months, ending on November 30, 2008.

RESULTS

Overall, mean 1-year graft survival was 86.9%, and mean creatinine concentration was 1.58 mg/dL. One incidence of primary nonfunction (0.6%) was observed. More than 25% of transplanted kidneys were from ECDs. No significant differences were noted in postoperative complications between recipients of ECD or SCD organs.

CONCLUSION

The rate of complications in recipients of ECD and SCD kidneys is comparable.

Serum concentration of vitamin D and parathyroid hormone after living kidney donation

BACKGROUND

Metabolic consequences resulting from loss of renal mass in living kidney donors remain uncertain. There is recent focus on the changes in the active form of vitamin D because it is an agent for cancer regulation. The objective of the study was to measure serum concentrations of 1,25-dihydroxycholecalciferol, parathyroid hormone and insulin-like growth factor-1 (IGF-1) in living donors after kidney donation.

PATIENTS AND METHODS

Forty living kidney donors reported for follow-up visits. Their mean age was 46.14 years. They were women in 52.5% of cases. The mean observation period was 65.6 months. Serum 1,25(OH)2D3 and IGF-1 concentrations were measured by radioimmunoassay after extraction. Serum intact parathyroid hormone (PTH) was quantified using an enhanced chemiluminescence immunoassay system.

RESULTS

1,25-dihydroxycholecalciferol deficiency in 57.5% patients after nephrectomy was the most important change we noted. No correlation was observed between 1,25(OH)2D3 and PTH. A decreased serum IGF-1 concentration was observed in 17.5% of donors. However, decreases in both serum IGF-1 and 1,25(OH)2D3 concentrations were observed in 12.5% of donors.

CONCLUSION

Prospective studies may be essential to determine metabolic changes after nephrectomy among living kidney donors.

Molecular epidemiology of vancomycin-resistant Enterococcus faecalis among patients of transplantology wards

OBJECTIVE

Vancomycin-resistant enterococci (VRE) require epidemiological monitoring especially in transplantation wards. The aim of our work was to perform a molecular analysis of vancomycin-resistant Enterococcus faecalis (VREfl) strains among solid organ recipients during various years.

MATERIALS AND METHODS

Strains were examined for the presence of different genes determining vancomycin resistance: vanA, vanB, vanD, or vanG by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP)-pulsed field gel electrophoresis (PFGE) was performed on bacterial DNA digested with SmaI enzyme.

RESULTS

From 2003 to 2006, we isolated 12 strains of VREfl from 8 patients (2 liver and 6 kidney transplantations). All strains harbored the vanA gene. Among the strains, 5 displayed patterns similar to each other, despite being isolated from different patients, and were susceptible to ampicillin with high resistance to aminoglycosides.

CONCLUSIONS

These results suggested that a single strain of VREfl was present for 3 years in closely related hospital wards, but it disappeared in the following years.