Molecular Characterization of Four Carbapenem-Resistant (CR) Isolates From a Single Patient

ALESSANDRO MORIANO; TRAGLIA, GERMAN MATIAS; CECILIA CORIGLIANO; JENNIFER S. FERNANDEZ; AGUSTINA FRANCH; ALMUZARA, MARISA; AMPARO HOARD; SABRINA MONTAÑA; EMILIA COHEN; RAMIREZ, MARÍA SOLEDAD

Congreso; ASM Microbe 2019; 2019

The infections with gram-negative bacilli producing carbapenemase is a worldwide major concern. Carbapenemases are not only associated with alarming rates of mortality, but also limited treatment options for infections caused by these organisms. Here we describe the molecular characterization of four carbapenem-resistant (CR) isolates from a 55-year-old male patient with a history of chronic obstructive pulmonary disease, hypertension, and diabetes. The patient was admitted to the intensive care unit due to cranial brain trauma requiring craniectomy with evacuation of the intracerebral hematoma plus surgical clipping of the sylvian aneurysm and placement of an external ventricular shunt.Four different carbapenem resistant isolates from different samples (blood cultures, catheters and urine cultures) of the same patient were obtained. A Klebsiella pneumoniae (Kb846), two Providencia stuartii (Ps848 and Ps850) and a Pseudomonas aeruginosa (PaC850) isolates developed in the patient?s samples. The occurrence of four CR isolates recovered from the same patient, is not a common event. This lead us to characterize the isolates in more detail and try to determine the existence of genetic transfer among them.In order to perform the molecular characterization, total DNA extraction was carried out and used to screen the most prevalent carbepenemase genes (blaVIM, blaNDM, blaKPC, blaIMP), as well as, the presence of mobile elements by PCR reaction followed by sequencing. Moreover, whole genome sequencing (WGS) of the two P. stuartii strains was performed in order to observe the genotypic relationship within and identified additional resistance determinants.The results indicated that Ps848 and Ps850 were positive for blaNDM-1, and Kb846 was positive for blaKPC. However, negative results were obtained in all cases for PaC850. Positive amplifications for class 1 integrons were obtained in all the strains. WGS and PCR cartography revealed the same class 1 integron array in the two P. stuartii strains and PaC850, suggesting interspecies horizontal genetic transfer. Phylogenetic analysis showed that both P. stuartii strains belong to the same clone and share the same antibiotic resistance genes.In this work we present the molecular characterization of four CR isolates from a single patient. The spread of CR isolates remains a significant clinical and public health concern. Therefore, we considered that the detection of CR isolates is an essential first step in combating this problem.