Antibiotic Susceptibility of <i>Cronobacter</i> spp. Isolated from Clinical Samples

Abstract

<i>Cronobacter</i> spp. have been recognized as causative agents of various severe infections in pre-term or full-term infants as well as elderly adults suffering from serious underlying disease or malignancy. A surveillance study was designed to identify antibiotic resistance among clinical <i>Cronobacter</i> spp. strains, which were isolated from patients of two hospitals between May 2007 and August 2013. Altogether, 52 <i>Cronobacter</i> spp. isolates were analyzed. Although MALDI-TOF mass spectrometry recognized all <i>Cronobacter sakazakii</i> and <i>Cronobacter malonaticus</i> strains, it could not identify <i>Cronobacter muytjensii</i> strain. Nevertheless, all strains were identified as <i>Cronobacter</i> spp. using multilocus sequence typing (MLST). Strains were tested against 17 types of antibiotics, using the standard microdilution method according to the 2018 European Committee on Antimicrobial Susceptibility Testing criteria. Three <i>Cronobacter</i> species were identified as <i>C. sakazakii</i> (n = 33), <i>C. malonaticus</i> (n = 18), and <i>C. muytjensii</i> (n = 1); all isolates were susceptible to all tested antibiotics. All strains were PCR-negative for <i>bla</i> _TEM, <i>bla</i> _SHV, and <i>bla</i> _CTX-M β-lactamase genes, as well. Even though the results of this study showed that <i>Cronobacter</i> spp. isolates were pan-susceptible, continued antibiotic resistance surveillance is warranted.