Cooccurrence of Multiple AmpC β-Lactamases in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in Tunisia

Abstract

e Over a period of 40 months, plasmid-mediated AmpC ␤-lactamases were detected in Tunis, Tunisia, in 78 isolates (0.59%) of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. In 67 isolates, only one ampC gene was detected, i.e., bla CMY-2-type (n ‫؍‬ 33), bla ACC (n ‫؍‬ 23), bla DHA (n ‫؍‬ 6) or bla EBC (n ‫؍‬ 5). Multiple ampC genes were detected in 11 isolates, with the following distribution: bla MOX-2 , bla FOX-3 , and bla CMY-4/16 (n ‫؍‬ 6), bla FOX-3 and bla MOX-2 (n ‫؍‬ 3), and bla CMY-4 and bla MOX-2 (n ‫؍‬ 2). A great variety of plasmids carrying these genes was found, independently of the species and the bla gene. If the genetic context of bla CMY-2-type is variable, that of bla MOX-2 , reported in part previously, is unique and that of bla FOX-3 is unique and new.A mpC ␤-lactamases are cephalosporinases that are poorly inhibited by clavulanic acid (1). AmpC production is one of the mechanisms of resistance to ␤-lactams in enterobacteria, conferring resistance to all ␤-lactams except fourth-generation cephalosporins and carbapenems (2). The genes encoding these enzymes are chromosome or plasmid borne (3).Most plasmid-borne AmpC (pAmpC) ␤-lactamase genes are derived from chromosomal genes that have been mobilized onto plasmids. Based on sequence similarities with species-specific AmpC enzymes, pAmpC variants are classified into five evolutionary groups: the CIT variants (CMY-2 types) originating in Citrobacter freundii, the Enterobacter sp. EBC variants (ACT-1 type, MIR-1), the Morganella morganii DHA variants, the Hafnia alvei ACC variants, and the Aeromonas sp. FOX and MOX variants (1, 2). Several genetic elements are involved in the mobilization of pAmpC ␤-lactamase genes, e.g., the insertion sequences IS26 (CMY-13), ISEcp1 (CMY-2-type, ACC-1-type), and ISCR1, associated with complex integrons (DHA-1 type) (1, 2).The geographic scattering of the different types of pAmpC shows that the CMY-2 type is the most frequent, particularly in Europe (e.g., in France, Spain, Italy,), in Canada, Argentina, and Tunisia (8-10), and in Korea and China (11,12). These pAmpC ␤-lactamases were detected among Enterobacteriaceae, especially in Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Salmonella enterica, and Proteus mirabilis, and also in naturally AmpC-producing species such as Enterobacter cloacae, Enterobacter aerogenes, and C. freundii (13-15).The pAmpC genes have also been reported in animals. Indeed, in the United States, CMY-2-producing E. coli strains have been found among canine clinical isolates (16). Clinical disease associated with AmpC-producing E. coli in dogs in Australia was first reported in 2006 (17). More recently, a survey of clinical isolates of E. coli from dogs and horses in the Netherlands revealed that 2% of them were AmpC producers (8). Furthermore, a Swedish study has described CMY-2-producing E. coli isolated from broilers (18). Such enzymes have been found in Klebsiella isolates from companion animals in Italy (19). In Tunisia, CMY-2-producing E. coli isolate...

High prevalence of multidrug resistant ESBL- and plasmid mediated AmpC-producing clinical isolates of Escherichia coli at Maputo Central Hospital, Mozambique

“…The nding of multiple pAmpC-bla genes in single strains has recently been reported in a Tunisian study. Brie y, a total of 11 out of 75 pAmpC positive clinical strains of Enterobacterales were shown to contain up to three different pAmpCs [10]. In contrast to our study, CMY-2 was the most common pAmpC-type in their study.…”

Comparison between Multiplex PCR and Phenotypic Detection Methods for Identifying AmpC B-lactamases Among Clinical Isolates of Enterobacteriaceae in Zagazig University Hospitals, Egypt

“…In the present study, multiplex PCR revealed that CIT is the most predominant gene (64.3%) followed by MOX (21.4%) and DHA (14.3%). CIT-type enzymes appear to be prevalent in China [20], India [34], Turkey [18] and Tunisia [35]. In Egypt, these results agreed with studies carried by [17,23,36] in, which CIT showed the highest prevalence rate (86.9%, 76.5% and 60% respectively).…”

Studies on avian pathogenic Escherichia coli in commercial broiler chicken in South East Queensland

“…Extended-spectrum cephalosporin resistance was encoded by bla CMY-2 and bla DHA-1 genes, which have been previously reported in other animals and other bacterial species in Australia (Abraham et al, 2014;Cherif et al, 2015;Rogers et al, 2014;Sidjabat et al, 2007), but not previously in poultry. The bla CMY-2 gene is the most frequently detected AmpC β-lactamase in food-producing animals worldwide (Borjesson et al, 2013;Bortolaia et al, 2010;Cherif et al, 2015;El-Shazly et al, 2017;Ewers et al, 2012;Jacoby, 2009 Lee et al, 2010;Maamar et al, 2016;Mataseje et al, 2010;Pacholewicz et al, 2015;Rasmussen et al, 2015;Rayamajhi et al, 2010;Rayamajhi et al, 2008;Tagg et al, 2015;Yan et al, 2006).…”

“…The bla CMY-2 and bla DHA-1 genes have been previously reported in other animals and other bacterial species in Australia (Abraham et al, 2014;Cherif et al, 2015;Rogers et al, 2014;Sidjabat et al, 2007). This is of great public health significance as those genes can be transmitted directly (via the food chain or environment) or indirectly (via mobilised plasmid) to other bacterial species…”