Polyclonal emergence of MDR Enterobacter cloacae complex isolates producing multiple extended spectrum beta-lactamases at Maputo Central Hospital, Mozambique

Abstract
Enterobacter spp. are important nosocomial pathogens responsible of a wide variety of infections, mainly due to Extended Spectrum β-Lactamase (ESBL) producing isolates, constituting a global public health issue in terms of clinical treatment and infection control, especially in low-income countries, where last-line treatment is often unavailable and there is weak nosocomial surveillance. In this study, we conducted a phenotypic and molecular characterization of 8 clinical Enterobacter spp. strains, isolated from patient’s blood in three hospitals in Mozambique. Isolates were identified by MALDI-TOF and anti-microbial Susceptibility Testing was performed by VITEK 2 system. Half of isolates were analyzed by PCR for β-lactamases genes, other isolates by Whole Genome Sequencing. We identified all isolates as Enterobacter cloacae complex (ECC), those from Maputo Central Hospital were polyclonal, multidrug resistant (5/8), and ESBL producers (50%), carrying blaCTX-M-15 and different assortment of blaSHV-12, blaTEM-1B and blaOXA-1, and AmpCs blaCMH-3, blaACT-7 and blaACT-9 genes. Resistance determinants linked to fluoroquinolone (aac(6')Ib-cr and qnrB1) and others antimicrobials were also found. Notably, one isolate showed phenotypically resistance to colistin, while another colistin susceptible isolate carried a silent mcr-9 gene. ECC nosocomial surveillance is urgently needed to contain and prevent the dissemination of ESBLs producing clones, and mcr-9 spread to other Enterobacteriaceae.