Emergence and clonal dissemination of carbapenem-hydrolysing OXA-58-producing Acinetobacter baumannii isolates in Bolivia

Abstract

and the presence of carbapenemases as a mechanism of resistance to imipenem. Isolates were obtained from 46 patients (one isolate per patient; 30 males,16 females) with an age range of 1 day to 84 years, and were collected from different sample types, the majority from respiratory tract infections (17) and wounds (13). Resistance to imipenem was detected in 15 isolates collected from different hospitals of the city. These isolates grouped into the same genotype, named A, and were resistant to all antibiotics tested including imipenem, with susceptibility only to colistin. Experiments to detect carbapenemases revealed the presence of the OXA-58 carbapenemase. Further analysis revealed the location of the bla OXA-58 gene on a 40 kb plasmid. To our knowledge, this is the first report of carbapenem resistance in A. baumannii isolates from Bolivia that is conferred by the OXA-58 carbapenemase. The presence of this gene in a multidrug-resistant clone and its location within a plasmid is of great concern with regard to the spread of carbapenem-resistant A. baumannii in the hospital environment in Bolivia. INTRODUCTIONAcinetobacter baumannii is a nosocomial pathogen responsible for severe infections often diagnosed in patients attending hospitals worldwide. Carbapemens are considered the drugs of choice for treating these infections, but they are not always efficient due to the occurrence of multidrug-resistant strains of this bacterium (Canduela et al., 2006;Coelho et al., 2006;Higgins et al., 2010a;Mendes et al., 2009;Poirel et al., 2010). Mechanisms enabling the development of carbapenem resistance include an induced decrease in membrane permeability, efflux pump overexpression and the production of carbapenemases. Among these mechanisms, the production of carbapenemases plays a major role in carbapenem resistance in most Gram-negative bacilli, including A. baumannii clinical isolates (Canduela et al., 2006;Coelho et al., 2006;Poirel et al., 2010;Queenan & Bush, 2007;Walsh, 2010). The most common type of enzyme occurring in A. baumannii is represented by the carbapenem-hydrolysing class D b-lactamases, which are divided into five phylogenetic groups: OXA-23-like, OXA-24-like, OXA-58-like, OXA-51-like, which is intrinsic to A. baumannii, and the recently described OXA-143-like enzymes (Higgins et al., 2009;Queenan & Bush, 2007).Although A. baumannii is considered an emerging pathogen and much research has been carried out on it, there have been only a few studies concerning the mechanisms conferring carbapenem resistance of this bacterium in Latin American countries (Celenza et al., 2006;Coelho et al., 2006;Sader et al., 2004;Sgambatti et al., 2010). In addition, there are no previous publications regarding the resistance of A. baumannii to imipenem or the occurrence of carbapenemases in A. baumannii isolates in Bolivia.In this study, we analysed the antibiotic resistance, in particular to imipenem, of clinical isolates of A. baumannii obtained from several hospitals in Cochabamba, Bolivia, and the presence of carbape...

First detection of the blaOXA-23 gene in a multidrug-resistant A. baumannii clinical isolate from Cochabamba, Bolivia

“…Moreover, an important increase in the resistance rates occurred from 2008 to 2014, increasing from 35% to 82.8% for imipenem and from 0% to 19.1% for colistin [3,4]. This increasing trend has also been observed in previous Pan American Health Organization (PAHO) and nationwide reports [5,6].…”

“…Detection of hybrids Typing experiments to determine clonal relationship with other worldwide genotypes revealed that Bo995 did not belong to international clones I, II, or III. Moreover, no homology was found with isolates that had been previously identified in the same hospital [3,4]. The dissemination of the blaOXA-23 gene through South America has been related to both monoclonal and polyclonal spread [6,14], so further genotypic analysis is needed to demonstrate the epidemiological origin of Bo995, and in-depth surveillance studies must be carried out in order to prevent the spread of this strain.…”

Multi-drug resistance profiles and the genetic features of Acinetobacter baumannii isolates from Bolivia

“…All strains except isolate 2 were resistant to one or more antibiotics tested. They had previously been confirmed to be clonally related according to their PFGE profiles [22].…”

Sequential outbreaks in a Spanish hospital caused by multiresistant OXA-58-producing Acinetobacter baumannii ST92

“…Of the 83 carbapenem-resistant A. baumannii clinical isolates collected from a series of patients in Spain, 19.3 % were OXA-58-like producers (Ruiz et al, 2007). The appearance and clonal dissemination of carbapenemhydrolysing OXA-58-producing A. baumannii isolates have been described recently in Bolivia (Sevillano et al, 2012).…”