Incidence and Risk Factors of Bacterial Infections in Children and Adolescents Following Allogeneic Hematopoietic Stem Cell Transplantation

Introduction:Bacterial infections are serious complication following allogeneic hematopoietic stem cell transplantation (HSCT). There are limited data on the incidence and risk factors in pediatric recipients

Patients and Methods: We retrospectively reviewed medical records of all pediatric patients who received allogeneic HSCT between January 2008 and April 2014 at King Hussein Cancer Center (KHCC) in Jordan. All bacterial infections including blood and non-blood related were included. No prophylaxis antibiotic was routinely used. Piperacillin and Amikacin were used empirically for fever episodes during the first 100 days following HSCT

Results: A total of 200 pediatric patients were identified, with median age of 9 year (2 month-27 year). Sixty percent (n=119) were males. One hundred and nineteen patients (60%) had non-malignant diseases. Peripheral blood (PB) was the stem cell source in 110 (55%), 69 (34.5%) bone marrow and 21 (10.5%) cord blood. Sixty nine percent received myeloablative conditioning (n=137), 26% reduced intensity (n=52) and 5% no conditioning regimen (n=11). One hundred eighty two (91%) were matched-related (140 were HLA identical siblings and 42 were other family donors). A total of 151 bacterial infections were documented in 77 patients (39%). Gram positive (GP) isolates were slightly more prevalent (52%) than gram negative (GN) (48%). One hundred and five episodes were isolated from blood stream (70%), 38 from skin, nasal and throat swabs (24.7%), and 8 from urine (5.3%). The GP isolates were more prevalent from blood stream, while GN were the prevalent ones at other sites (p=0.001). Coagulase negative staphylococcus (CONS) was the most predominant isolate in all sites (33%), followed by Escherichia coli (15%). Most of the bacterial infection episodes (60%) occurred prior to neutrophil engraftment. Eight deaths (10.3%) were attributed to bacterial infection. Risk factors associated with higher risk of bacterial infections included age < 2 years at transplantation (p=0.001), use of PB (p=0.038), myeloablative conditioning (p=0.027), mismatched or unrelated donor (p= 0.002), family donors other than identical siblings (p=0.046), use of TPN (p=0.046), and morphine use for more than 5 days (p=0.011) due to significant mucositis. In a multivariate analysis; age at transplantation < 2 years (HR=6.834; 95% CI 1.528-30.572; p=0.0119) was the only factor associated with higher risk for bacterial infection post HSCT

Conclusion: Bacterial infections are common following allogeneic HSCT in children and adolescents not receiving antibiotic prophylaxis and are associated with significant risk of mortality. Children below 2 years of age are at higher risk. We have prospectively implemented an antibiotic prophylaxis regimen in an effort to decrease bacterial infections.