Invasive pneumococcal disease in pediatric organ transplant recipients: a high-risk population

There are few studies on invasive pneumococcal disease in pediatric transplant recipients. Given this fact plus the advent of pneumococcal conjugate vaccines, we conducted a retrospective study at a major pediatric transplant center. The objectives were to determine the incidence and outcomes of invasive pneumococcal diseases in the patient population and to examine the timing of these infections after transplantation. We determined that invasive disease occurred at a rate that was significantly greater than the rate extrapolated from generally healthy children <5 yr of age (176 episodes per 100 000 children per year vs. 35-68.3 per 100 000 children per year). In addition, disease occurred at a median of approximately 20 months after transplantation, thereby theoretically allowing enough time for vaccination with the 7-valent conjugate vaccine. The study also documented significant missed vaccination opportunities.     

A quality improvement initiative to increase pneumococcal vaccination coverage among children after kidney transplant

Pneumococcal vaccination rates among children receiving a kidney transplant remain suboptimal. Current practice guidelines in the United States recommend giving the PPSV23 after priming with the PCV13. We conducted a QI initiative to increase pneumococcal vaccine rates in our kidney transplant recipients by developing an age‐based vaccine algorithm, obtaining vaccine records, and generating reminders for patients and clinicians. A monthly report from the EHR tracked outcomes. The process metric was missed vaccine opportunities, and the overall objective was to improve coverage with both the PCV13 and PPSV23. Over the first six months, we increased the percentage of visits where the vaccine was given from a baseline of 4% to 33%. However, by the end of the 12‐month period, the percentage of eligible visits where the vaccine was given decreased to 8.7%. Nevertheless, over the 12‐month observation period, we were able to increase the percentage of transplant patients receiving the PCV13 and PPSV23 from 6% to 52%. Utilizing an age‐based algorithm and the electronic medical record, vaccine champions can track both missed visit opportunities and the number of vaccinated patients to improve pneumococcal immunization coverage for these high‐risk patients.     

Invasive pneumococcal infections in pediatric cardiac transplant patients

BACKGROUND: Bacterial infections cause significant morbidity and mortality in cardiac transplant patients. Because Streptococcus pneumoniae is the most prominent bacterial pathogen of childhood, the objective of this study was to define the role of S. pneumoniae as a pathogen in the cardiac transplant population. METHODS: Medical records of cardiac transplant patients from March, 1990, through November, 2000, were reviewed to identify invasive pneumococcal infections after transplantation. Demographic, clinical and microbiologic data were reviewed. RESULTS: Nine (11%) of 80 patients had 12 episodes of pneumococcal bacteremia for an incidence rate of 39 cases/1,000 patient years. Patients who were African-American, transplanted before 2 years of age and transplanted because of idiopathic dilated cardiomyopathy were at increased risk of invasive pneumococcal disease (P < 0.05). Six patients were eligible for the 23-valent pneumococcal polysaccharide vaccine before their first invasive infection, but only 1 had received it at the recommended age. Most isolates (82%) were penicillin-susceptible, and no single serotype predominated. There were 2 deaths in the study group, but each was unrelated to infection. Three patients (33%) had recurrent invasive disease with a second serotype an average of 12 months after the first infection. CONCLUSIONS: The incidence of pneumococcal bacteremia in cardiac transplant patients is higher than in the general pediatric population. Risks for infection were being African-American, being younger than 2 years at the time of transplant and being transplanted because of idiopathic cardiomyopathy. It is plausible that pneumococcal vaccine would decrease this risk.     

Post‐transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection‐prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.     

Chronic high Epstein–Barr viral load carriage in pediatric small bowel transplant recipients

Lau AH, Soltys K, Sindhi RK, Bond G, Mazariegos GV, Green M. Chronic high Epstein–Barr viral load carriage in pediatric small bowel transplant recipients.
Pediatr Transplantation 2010: 14:549–553. © 2010 John Wiley & Sons A/S. Abstract: The development of EBV infection and PTLD is normally associated with a high EBV load in peripheral blood. Often, children undergoing primary or reactivation of EBV infection subsequent to ITx will have chronically elevated EBV loads. To better understand this phenomenon and its consequences, we retrospectively reviewed the records of children who underwent ITx (either isolated or part of multivisceral transplantation) at our center from 1992 to 2007, to identify chronic high EBV load carriers in this population. CHL state was defined as the presence of high load for >50% of samples for greater than or equal to six months following either asymptomatic infection or complete clinical resolution of EBV disease/PTLD. Thirty‐five CHL carriers were identified from our patient population. Pretransplant serologies were available on 34 of these patients: 17 were EBV negative and 17 seropositive; one had unknown EBV serostatus prior to transplant. Seven of the 17 seronegative patients developed their CHL carrier state at the time of their primary EBV infection. Thirteen of the 35 (37%) HLC patients developed EBV disease after meeting the definition of high‐load carrier states. EBV‐related diseases developing in CHL carriers included EBV adenitis (n = 1), EBV enteritis (n = 7), PTLD (n = 4), and EBV+ spindle cell tumor (n = 1). Disease was seen in 7/17 of the seronegative (one PTLD) and 6/17 of the seropositive patients (three PTLD). Thirteen of 35 patients (37%) resolved their CHL state without apparent sequelae while nine remain asymptomatic CHL carriers. Three children have had more than one episode of CHL. These data provide important information about the outcome of chronic EBV high‐load carriage in pediatric intestinal transplant recipients.     

Post‐transplant malignancies in pediatric organ transplant recipients

The majority of cancer diagnoses in pediatric solid organ transplant recipients (SOTRs) are post‐transplantation lymphoproliferative disorders (PTLD) or skin cancers. However, pediatric SOTRs are also at significantly elevated risk for multiple other solid and hematological cancers. The risks of specific cancers vary by transplanted organ, underlying disease, and immunosuppression factors. More than one‐quarter of pediatric SOTRs develop cancer within 30 years of transplantation and their risk of solid cancer is 14 times greater than the general population. Pediatric SOTRs are at significantly higher risk of cancer‐associated death. Improving patient survival among pediatric SOTRs puts them at risk of adult epithelial cancers associated with environmental carcinogenic exposures. Vaccination against oncogenic viruses and avoidance of excessive immunosuppression may reduce the risk of solid cancers following transplantation. Patient and family education regarding photoprotection is an essential component of skin cancer prevention. There is significant variability in cancer screening recommendations for SOTRs and general population approaches are typically not validated for transplant populations. An individualized approach to cancer screening should be developed based on estimated cancer risk, patient life expectancy, and screening test performance.     

Impact of surveillance stool culture guided selection of antibiotics in the management of pediatric small bowel transplant recipients

Surveillance stool cultures (SSC) have been used in immunocompromised populations to predict the organisms associated with invasive infections and aid in the selection of empiric antibiotic regimens. To evaluate the utility of this approach in pediatric small bowel transplant (SBT) recipients, we conducted a retrospective review of 33 patients who underwent SBT, 16 of whom had SSC done. In no case was the same organism isolated from SSC and subsequent blood, peritoneal fluid or wound cultures. In the first month post-transplantation, blood cultures were positive in 44% and 35% of patients that had and did not have SSC done, respectively (p = 0.73); peritoneal fluid cultures in 44% and 65% (p = 0.30); and wound cultures in 44% and 24% (p = 0.28). There were no significant differences among both groups in time to first infection, duration of ICU stay following SBT, graft survival or long-term patient survival. We conclude that SSC-guided antibiotic selection does not have a significant impact on the incidence of invasive infections in the first month following SBT or on specific indicators of patient outcome. This suggests that empiric antibiotic regimens should be selected based on clinical presentation and hospital flora and susceptibility patterns.     

Respiratory syncytial virus infections in pediatric transplant recipients: A Canadian Paediatric Surveillance Program study

The incidence and spectrum of severity of RSV infections in SOT or HSCT recipients is not known. From September 2010 through August 2013, pediatricians were surveyed monthly by the CPSP for SOT or HSCT recipients with RSV infection within two yr post‐transplant. There were 24 completed case report forms that fit the inclusion criteria (10 HSCT and 14 SOT recipients). Six of 24 cases (25%) remained outpatients, and 11 (46%) were managed on an inpatient ward, while seven (29%) required intensive care of which five required mechanical ventilation and two died of RSV infection. Ten of 23 cases (43%) were nosocomial with these data not recorded for one case. Many transplant recipients recover uneventfully from RSV infection in the first two yr post‐transplant. However, severe disease and death also occur. Larger studies are required to establish risk factors for poor outcomes. Prevention of nosocomial RSV should be a priority in transplant recipients.     

Serotype replacement of Streptococcus pneumoniae due to seven‐valent pneumococcal conjugate vaccine in Japan

Background

This study examined the trends for the serotypes of S. pneumoniae that have caused infections before (2010) and after (2012) the introduction of PCV‐7 in Japan.

Methods

We examined 458 strains of Streptococcus pneumoniae obtained from 22 pediatric institutions throughout Japan from January to June 2010 (immediately after the introduction of the seven‐valent pneumococcal conjugate vaccine [PCV‐7]), and 370 strains obtained from 19 institutions from January to June 2012 (after PCV‐7 became widely used). The samples were collected from children aged 0–14 years with conditions such as respiratory tract infections (upper airway inflammation, bronchitis, and pneumonia), meningitis, and sepsis.

Results

The most frequent serotype in the 2010 strains was 19F (17.3%), followed by 6B (16.8%), and 23F (15.1%). The most frequent serotype in the 2012 strains was 6C (10.0%), followed by 19F (9.7%), 15A (8.9%) and 15B (8.9%), indicating a significant change in the distribution. The serotypes contained in PCV‐7 were detected in 280 strains (61.1%) in 2010 and in 81 strains (21.9%) in 2012 (P < 0.01). The serotypes contained in PCV‐13 were detected in 356 strains (77.7%) in 2010 and in 146 strains (39.5%) in 2012 (P < 0.01). A total of 129 subjects who had not been vaccinated with PCV‐7 and 127 subjects who had been vaccinated with PCV‐7 at least once, were compared with regard to the 2012 strains. The serotypes contained in PCV‐7 were found in 21 strains (16.5%) in those who had been vaccinated and in 37 strains (28.7%) in those who had not been vaccinated (P < 0.05).

Conclusions

The increased use of PCV‐7 led to decreases in the serotypes contained in PCV‐13 and increases in the serotypes not contained in PCV‐13, suggesting serotype replacement.     

Invasive pneumococcal disease in children with sickle cell disease in the pneumococcal conjugate vaccine era

Invasive pneumococcal disease (IPD) in children with sickle cell disease (SCD) can be devastating. We sought to assess the impact of IPD in children with SCD since licensure of the pneumococcal conjugate vaccines (PCVs). We found 11 cases of IPD giving an incidence of 417 per 100,000 person‐years, much higher than that reported in children without SCD. Although all isolates were sensitive to penicillin, 89% of isolates were nonvaccine serotypes. Further study is needed to characterize the incidence of and risk factors for the development of IPD in SCD in the PCV era to help drive better prevention strategies.     

Epidemiology of invasive and other pneumococcal disease in children in England and Wales 1996–1998

The results of enhanced national surveillance of pneumococcal disease in children <15y of age in England and Wales are reported for the period 1996–1998. Of the 1985 cases of laboratory-confirmed invasive disease (annual incidence 6.6 per 100000 overall and 39.7 per 100000 in infants <1 y of age), 485 (24%) were meningitis (annual incidence of 1.6 per 100000 overall and 15.7 per 100000 in infants <1 y of age). Fifty-nine deaths in children with invasive disease were identified-3% of the total reports. Thirty-one different serogroups/types were identified, with organisms in the 7-valent conjugate vaccine responsible for 69% of the infections in children <5 y of age; this rose to 77% and 82%, respectively, for the 9-and 11-valent vaccines. Resistance to penicillin varied from 2.3% to 6.2% in different years, but erythromycin resistance remained constant at 17%. The vast majority of resistant isolates were in vaccine serotype/groups. Computerized hospital admission records for all children <15 y of age with a discharge diagnosis code indicating probable pneumococcal disease were also analysed for 1997. The annual incidence for cases with a code specifically mentioning S. pneumoniae was 9.9 per 100000 compared with 71.2 per 100000 for lobar pneumonia; the mean duration of stay for both was < 1 wk. The incidence of admission for pneumococcal meningitis (1.9 overall and 19.6 for infants < 1 y of age) was similar to that derived from laboratory reports and resulted in an average duration of stay of 2 wk.
Conclusion : This surveillance has confirmed the substantial burden of morbidity attributable to pneumococcal disease in British children and the potential public health benefits that could be achieved by the use of pneumococcal conjugate vaccines.     

Invasive fungal infections in pediatric heart transplant recipients: incidence, risk factors, and outcomes

There are limited data on the incidence or risk factors for IFI in pediatric heart transplant recipients. The purpose of this study was to describe the incidence and types of IFI, to determine risk factors for outcomes of IFI, and to assist in decision-making concerning the need for prophylactic strategies in pediatric heart transplant recipients. Data from a multi-institutional registry of 1854 patients transplanted between 01/93 and 12/04 were analyzed to determine risk factors and outcomes of children with IFI post-heart transplantation. One hundred and thirty-nine episodes of IFI occurred in 123 patients and made up 6.8% of the total number of post-transplant infections. IFI was most commonly attributed to yeast (66.2%), followed by mold (15.8%) and Pneumocystis jiroveci (13%). Ninety percent of the yeast infections were caused by Candida spp., and Aspergillus spp. was causative in 82% of the mold infections. There was a significantly increased risk of fungal infection associated with pretransplant invasive procedures (e.g., ECMO, prior surgery, VAD, mechanical ventilation) with an incremental risk with increasing numbers of invasive procedures (early phase 0 vs. 1, RR 1.3; 0 vs. 3, RR 2.3; p<0.001). In multivariate analysis, previous surgery (p=0.05) and mechanical support at transplantation (p=0.01) remained significant. Forty-nine percent of recipients with IFI died, all within six months post-transplant. Invasive fungal infections are uncommon in pediatric heart transplant recipients. Risk and mortality are highest in the first six months post-transplant especially in patients with previous surgery and those requiring mechanical support. Prophylactic strategies for high-risk patients should be considered and warrants further study.     

Effect of the pneumococcal conjugate vaccine on pneumococcal carriage in Turkish children

Background: The aim of our study was to evaluate the effect of the seven‐valent pneumococcal conjugate vaccine which has recently been included in the national immunization schedule on the nasopharyngeal carriage of Streptococcus pneumoniae in a group of healthy Turkish children. This is the first study determining the efficacy of this vaccine in Turkey. Methods: One hundred and thirty‐eight children who had completed their pneumococcal vaccination series and 109 unvaccinated control subjects aged 12–59 months were included in the study between October 2007 and April 2008. A single nasopharyngeal swab sample was obtained from each subject. Results: S. pneumoniae was isolated in 32 (12.9%) of 247 subjects. No significant differences were detected in pneumococcal carriage rate between the vaccinees and controls (10.1% vs 16.5%). Prevalence of vaccine type (VT) carriage was statistically lower in the vaccinated group than the controls while non‐vaccine type carriage (NVT) was similar. Most frequently isolated vaccine serotype was 23F in the vaccinated group and 19F in the non‐vaccinated group. Of the isolated S. pneumoniae, 13.3% were penicillin susceptible and 86.7% were non‐susceptible. Vaccinees and controls did not differ statistically with respect to carriage rate of penicillin‐resistant S. pneumoniae. All the pneumococcal isolates were susceptible to ceftriaxone, vancomycin, rifampicin and quinolones. Conclusion: Seven‐valent conjugate vaccine induces long‐term protection against carriage of VT S. pneumoniae in Turkish children. The ability of the conjugate vaccine to reduce transmission of antibiotic resistant S. pneumoniae may be possible if its introduction is coupled with a reduction in inappropriate use of antibiotics.     

Predictors of cardiac allograft vasculopathy in pediatric heart transplant recipients

CAV remains a leading cause of late graft loss and mortality among survivors of pediatric heart transplantation. We sought to define the incidence of CAV and identify its predictors in pediatric heart transplant recipients. The OPTN/UNOS database was analyzed for pediatric recipients who underwent heart transplant between 1987 and 2011. The primary end‐point is time from heart transplantation to development of CAV (CAV‐free survival). To identify predictors of CAV‐free survival, demographic and transplant data were analyzed by the Kaplan–Meier survival method and Cox proportional hazards regression. Of 5211 pediatric heart transplant recipients with at least one‐yr follow‐up, the incidence of CAV at five, 10, and 15 yr was 13%, 25%, and 54%, respectively. Multivariate analysis found that risk of CAV was associated with the following variables: Recipient age 1–4 yr (HR 1.25), 5–9 yr (1.45), 10–18 yr (1.83), donor age >18 yr (1.34), re‐transplantation (2.14), recipient black race (1.55), and donor cigarette use (1.54). Older recipient and donor age, recipient black race, donor cigarette use, and re‐transplantation were highly associated with shorter CAV‐free survival.     

Unusual presentations of BK virus infections in pediatric renal transplant recipients

BKV has emerged as a significant pathogen in the field of transplantation, predominantly causing BKV nephropathy in renal transplant recipients and hemorrhagic cystitis in HSCT recipients. However, case reports describe more diverse complications, and we too present three unusual cases of BKV infections in pediatric renal transplant recipients. First, we describe a case of biopsy‐proven renal damage secondary to BKV prior to the onset of viremia, demonstrating that BKV nephropathy can occur without preceding viremia. We also present two renal transplant recipients with persistent BK viruria, one with BKV‐associated hemorrhagic cystitis and the other with microscopic hematuria. Therefore, we conclude that BKV manifestations may be more diverse than previously thought and suggest clinical utility in urine BKV qPCR testing in specific transplant recipients.     

The use of sirolimus as a rescue therapy in pediatric intestinal transplant recipients

To review our experience with SRL as a second-line therapy in our series of 45 SBTx recipients (1997-2009). Retrospective review of five children converted to SRL: 3 M/2 F; median of three yr old (range 20 months-18 yr); rescue indications, adverse events with SRL, resolution of tacrolimus-related side effects, incidence of rejection, PTLD, or GVHD were summarized. Tacrolimus was discontinued (average 13 months after transplant) because of refractory hemolytic anemia in four patients with decreased renal function and because of advanced renal failure and unclear neutropenia in one. PTLD and GVHD had been previously diagnosed in two. Tacrolimus-related side effects disappeared in all five although other immunosuppressants and splenectomy were used simultaneously or later in most of them. Adverse events reported after the conversion were infections (tuberculosis and Pneumocystis carinii in two) and mild hypertriglyceridemia. No rejection, GVHD, or PTLD episode was observed. Four patients are alive with excellent quality of life (median follow-up 18 months). Sirolimus is a safe rescue therapy in SBTx children when tacrolimus is not well tolerated. Renal function and hematologic disorders seem to improve, although other simultaneous strategies could be also involved. Further studies could demonstrate its efficacy as a first-line treatment.     

Immune cell function assay in pediatric heart transplant recipients

The ImmuKnow^® ICFA reports ex vivo CD4 lymphocyte activation to quantify immunosuppression. Limited organ and age‐specific data exist for pediatric heart transplant recipients. We sought to examine their normative values and ICFA's association with rejection/infection. A total of 380 ICFAs from 58 heart transplant recipients (6.5/recipient) were studied retrospectively. The median age at the time of their first ICFA was 5.3 yr (IQR 2.4–12.1 yr). ICFA levels during immunologic stability (n = 311) were a median of 305 (IQR: 172–483) and mean of 353 (s.d. ± 224) ng ATP/mL. ICFA levels trended lower with advancing age. ICFA levels during immunologic stability increased over time from transplant after the first six months but were not correlated with calcineurin inhibitor levels or the type used. There is no association between ICFA values during stability and rejection (median 368 ATP ng/mL; IQR 153–527) or infection (median 293 ATP ng/mL; IQR 198–432). In contrast to the manufacturer's suggested ranges, the immunologic stable ranges in pediatric cardiac recipients were very different. ICFA values during immunologic stability are related to time from transplant in pediatric heart recipients. ICFA's ability to discriminate rejection or infection from immunologic stability was not demonstrated.