745. Comparative Analysis of Multi-Beta-Lactam Resistant and KPC-positive K. pneumoniae and E. coli Clinical Isolates in Puerto Rico for 2009 and 2012
Session: Poster Abstract Session: Antimicrobials: Resistance Mechanisms
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C

The carbapenem antibiotics are used for the treatment of multidrug resistant gram-negative bacterial infections. Bacteria that contain the Klebsiella pneumoniae carbapenemase (KPC) genes are resistant to the Beta-lactam antibiotics, including the carbapenems, and most have resistance factors to other antibiotics classes.  A previous 2009 island wide PCR surveillance study in Puerto Rico (PR) determined the presence of KPC-positive and KPC-negative, multi-beta lactam resistant (MBLR) Klebsiella pneumoniae (Kp) and Escherichia coli (Ec) clinical isolates. This finding highlights a serious medical problem as treatment options are limited. The aim of this study was to compare the KPC-positive and -negative MBLR Kp and Ec isolates, collected during 2 months in 2012 (Kp = 243; Ec = 134), with those obtained in 6 months in 2009 (Kp = 457; Ec= 219) , from the same 17 participating hospitals. MBLR was defined as resistant to any of the carbapenems and/or to two or more extended spectrum beta-lactam antibiotics.


PCR for the identification of KPC, TEM, SHV, CTX-Ms groups, IMP and VIM beta-lactamases genes was performed in all MBLR isolates and the results were subjected to statistical analysis.


Kp continue to be the most common KPC-positive organisms in all geographic areas.  There was no significant difference in the total percentage of KPC-positive Kp (5.5% and 5.6%) or Ec (1.5% and 1.7%) for both periods. No VIM or IMP genes were detected. For the 2012 period, a significant increase (p ≤ 0.01) in KPC-negative MBLR Kp (4% to 15%) and Ec (4% to 9 %) was observed. A highly statistically significant increase (p <0.0001) of CTX-M-1 gene in Ec and Kpisolates was identified in 2012.


The data suggests that KPC-positive Ec and Kp has remained stable during the 3-year period. The reasons for the significant increase in CTXM-1 gene are not clear from this study. We speculate that either, the increase burden and limitations in hospitals isolation rooms caused by KPC-positive bacteria and the MRSA, patients with ESBL positive organisms are not being properly isolated or that there has been an increase in the hospitalization of community patients already colonized or infected with ESBL-positive bacteria.

Teresa Martinez, PhDc1, Guillermo J Vazquez, MD2, Edna E Aquino, MT, PhD2, Jorge L Santana, MD, FIDSA3, Maria I Sante, MD4 and Iraida E Robledo, MS, PhD2, (1)Microbiology and Medical Zoology, University of Puerto Rico, School of Medicine, San Juan, PR, (2)Microbiology and Medical Zoology, Univ PR, School of Medicine, San Juan, PR, (3)Department of Internal Medicine, University of Puerto Rico, School of Medicine, San Juan, PR, (4)Pathology and Laboratory Medicine, University of Puerto Rico, San Juan, PR


T. Martinez, None

G. J. Vazquez, None

E. E. Aquino, None

J. L. Santana, None

M. I. Sante, None

I. E. Robledo, None

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