Description and Analysis of Bacteremia by Gram Negative Bacilli in Neutropenic Oncohematological Pediatric Patients in a Third Level Hospital
Authors: Sormani Maria Ines , Torre valeria , Alancay Alejandra , Regalado Anastasia , Fagnani Marcio , Lagala Yanina , Lovano Fiorella , Maydana Mara , Esposto Sofía , Morales Juan Carlos , Gil Maria Florencia , Fasano Maria Victoria 
Published: November 2023

Abstract

INTRODUCTION
Bacteremia is one of the main post-chemotherapy complications in oncohematological patients. Neutropenia is the most frequent risk factor for its development. Determining an adequate empirical treatment based on local epidemiology is essential to reduce the morbidity and mortality associated.

MATERIALS AND METHODS
A retrospective and descriptive study was performed. It included episodes of Gram-Negative Bacilli (GNB) bacteremia in neutropenic patients under 18 years of age with hemato-oncological diseases admitted to a high-complexity pediatric hospital from January 1, 2018 to December 31, 2021. Bone marrow and solid organ transplants were excluded.
In all cases, a p-value &lt;0.05 was considered significant. Statistical analysis was performed using R version 4.2.2.

OBJECTIVES
Evaluate the clinical and laboratory findings, microbiological characteristics, resistance patterns and empirical antibiotic treatment (EAT) of GNB bacteraemias in neutropenic oncohematological patients.

RESULTS
Fifty-two episodes of bacteremia were evaluated in 44 patients. Forty (76.9%) episodes presented severe neutropenia.
The median age was 128 (59;168) months and females were predominant (59.3%).
The most frequent underlying disease was acute lymphoid leukemia (ALL) in 30 cases (57.7%), of which 12 were relapsed (40%) and 9 (30%) induction.
The median number of days since the last chemotherapy was 10.
A percent of 78.8% (41/52) had platelets less than 50000 mg/dl; the PCR value was greater than 90 mg/dl in 44.2% (23/52) . Forty-two bacteremias (80.7%) presented with fever.
Thirteen (25%) primary bacteraemias were identified. As to secondary bacteremia, the main associated focus was the central venous catheter in 23 cases (44.2%) followed by abdominal focus in 13 (25%).
The most frequent bacteria were Escherichia coli (23), Klebsiella pneumoniae (13), Enterobacter cloacae (7), Stenotrophomonas maltophilia (3) and Pseudomonas aeruginosa (3).
In 18 of the microorganisms, multiresistance mechanisms (MDR) were detected, the main one being extended-spectrum beta-lactamases (ESBL) in 25% (13/52) with the following distribution: Klebsiella pneumoniae 69.2% (9/13), Escherichia coli 23.1 % (3/13), Enterobacter cloacae 7.7% (1/13). Moreover, two isolations of Enterobacter cloacae with resistance to cephalosporins due to hyperproduction of ampC-type Betalactamases and one of Klebsiella pneumoniae with the presence of Metallobetacarbapenemases (MBL) were detected.
The coverage against GNB was achieved mostly by piperacillin-tazobactam. In 32.6% of the cases the EAT was not adequate.
Fifteen patients (28.8%) developed septic shock, 7 of which showed ESBL-resistant microorganisms (p=0.034), 13 patients died and 8 of them presented MDR isolates (p= 0.037).

CONCLUSIONS
GNB MDR bacteremia in neutropenic oncohematological patients is associated with high morbidity and mortality. Knowing the local epidemiology in each institution is essential to establish an adequate EAT favoring the rational use of antibiotics and preventing increased resistance.