<i>In Vitro</i> Antimicrobial Susceptibility Differences Between Carbapenem-Resistant KPC-2-Producing and NDM-1-Producing <i>Klebsiella pneumoniae</i> in a Teaching Hospital in Northeast China

Abstract

Carbapenem-resistant <i>Klebsiella pneumoniae</i> (CRKP) has become a serious challenge for clinical treatment and public health. We found that both KPC-2-producing <i>K. pneumoniae</i> (KPC-KP) and NDM-1-producing <i>K. pneumoniae</i> (NDM-KP) are epidemic in a teaching hospital in Northeast China. The main aim of the present study was to compare antimicrobial susceptibility differences between KPC-KP and NDM-KP and elucidate complex resistant genotypes of the KPC-KP and NDM-KP by PCR and sequencing. Among 82 CRKP isolated between January 2015 and December 2016, 59 isolates were KPC-KP and 23 isolates were NDM-KP. All 59 KPC-KP had no susceptibility to gentamicin, tobramycin, levofloxacin, and ciprofloxacin, had very low susceptibility to amikacin (3.39%) and fosfomycin (8.47%), whereas the susceptibility of NDM-KP to the above antibiotics was 21.74%, 13.04%, 17.39%, 17.39%, 69.57%, and 73.91%, respectively. Although the susceptibility of NDM-KP to tigecycline (95.65%) and polymyxin B (73.91%) was higher than that of KPC-KP (84.75% and 69.49%, respectively), the difference was not statistically significant. The MIC₉₀ of KPC-KP and NDM-KP to aztreonam-avibactam were 4 and 2 μg/mL, respectively. All 82 CRKP carried 2 or 3 Extended Spectrum Beta-Lactamase (ESBL) genes, and 79/82 CRKP carried the AmpC gene <i>bla_FOX</i>. The aminoglycoside resistance gene <i>rmtB</i> was detected in 96.61% of KPC-KP and in 21.74% of NDM-KP. It seems that KPC-KP was more resistant to antibiotics than NDM-KP in this study, so that available therapeutic regimens against KPC-KP are very limited. Aztreonam-avibactam may be a promising and valuable option against both KPC-KP and NDM-KP.