Copyright@ Athanasios Galanopoulos | Biomed J Sci & Tech Res | BJSTR. MS.ID.005706. 27700 Research Article ISSN: 2574 -1241 An Outbreak of β -Lactamase Klebsiella Pneumoniae Carbapenemase 2–Producing Klebsiella Pneumoniae Bacteremia in Hematology Patients Panagiotis Bacarakos 1 , Maria Orfanidou 2 , George Ganteris 2 , Eleni Vagiakou 2 , Panagiota Giakkoupi 3 , Evridiki Michalis 1 and Athanasios Galanopoulos 1 * 1 Hematology Department, General Hospital “G. Gennimatas”, Greece 2 Department of Medical Microbiology, General Hospital “G. Gennimatas”, Greece 3 Department of Microbiology, National School of Public Health, Greece *Corresponding author: Athanasios Galanopoulos, General “G. Gennimatas” Hospital, Hematology Department, 154 Mesogion street, 11527 Athens, Greece DOI: 10.26717/BJSTR.2021.35.005706 ARTICLE INFO ABSTRACT We describe an outbreak of bacteremia due to carbapenem resistant Klebsiella pneumoniae carbapenemase-2 (KPC-2)- producing Klebsiella pneunoniae occurred in the Hematology Department of a tertiary care Hospital in Greece. From November 2016 through May 2019, 16 patients with hematologic malignancies, with prolonged history of hospitalization and prolonged administration of antibiotics, were colonized (n= 3), or infected (n= 13) by KPC-2-producing K.pneumoniae. Clinical diagnoses included pneumonia (50 % of cases), bacteremia (75 %) and urinary tract infection (12 %). Overall, 18 KPC-producing K.pneumoniae isolates, mainly from blood (94 %), urine (25%), respiratory (31%), gastrointestinal tract (31%) and catheter tip (6%) were identified. Most patients received a colistin-containing combination treatment. Crude mortality was 93,8% but attributable mortality was 68,8%. The emergence of KPC- producing K. pneumoniae is associated with significant morbidity and mortality among hematologic patients, and warrants focus on rational use of antibiotics, enhancement of infection control measures and implementation of antibiotic resistance surveillance. Keywords: Bacteraemia; KPC-2-Producing K.Pneumoniae; Outbreak; Hematologic Dis- orders Received: March 21, 2021 Published: April 30, 2021 Citation: Panagiotis B, Maria O, George G, Eleni V, Athanasios G, et al., An Outbreak of β -Lactamase Klebsiella Pneumoniae Carbapenemase 2–Producing Klebsiella Pneumoniae Bacteremia in Hematology Patients. Biomed J Sci & Tech Res 35(3)- 2021. BJSTR. MS.ID.005706. Introduction Carbapenems are frequently used for severe hospital infections caused by K. pneumoniae, especially when isolates produce extended-spectrum β-lactamases (ESBLs) or have chromosomal cephalosporinases. The last decade, several studies have documented the emergence of carbapenem resistant K. pneumoniae (CR-KP) worldwide and in Greece. Data from the Greek System for the Surveillance of Antimicrobial Resistance [1] show that among K. pneumoniae blood isolates, carbapenem resistance increased from <1% in 2001 to 42% in medical wards and to 72% in intensive care units (ICUs). Carbapenem resistance is mainly due to the production of carbapenemases which is considered to be the most important molecular mechanism. Carbapenemases belong to four molecular families but Classes A and B and D are of greater clinical importance. Classes A and B are distinguished by the hydrolytic mechanism at the active site. The carbapenemases of Class A utilize serine at their active sites, with KPC being the main representative. The carbapenemases of Class B contain at least one zinc atom at the active site, establishing them as metalloenzymes, with VIM and IMP representing the most prevalent enzymes [2]. In 2001, the first KPC-producing K. pneumoniae isolate was reported in North Carolina [3] and then several reports documented the emergence of Enterobacteriaceae strains from various species