Fernanda Esposito

Silent dissemination of colistin-resistant Escherichia coli in South America could contribute to the global spread of the mcr-1 gene.

During a Brazilian multicentric antimicrobial resistance surveillance study, colistin resistance was investigated in 4,620 Enterobacteriaceae isolated from human, animal, food and environmental samples collected from 2000 to 2016. We present evidence that mcr-1-positive Escherichia coli has been emerging in South America since at least 2012, supporting a previous report on the possible acquisition of mcr-1-harbouring E. coli by European travellers visiting Latin American countries.

First Report of the Globally Disseminated IncX4 Plasmid Carrying the mcr-1 Gene in a Colistin-Resistant Escherichia coli Sequence Type 101 Isolate from a Human Infection in Brazil

ABSTRACT A colistin-resistant Escherichia coli strain was recovered from a patient with a diabetic foot infection in Brazil. Whole-genome analysis revealed that the E. coli isolate belonged to the widespread sequence type (ST) 101 and harbored the mcr-1 gene on an IncX4 plasmid that was highly similar to mcr-1-bearing IncX4 plasmids that were recently identified in Enterobacteriaceae from food, animal, and human samples recovered on different continents. These results suggest that self-transmissible IncX4-type plasmids may represent promiscuous plasmids contributing to the intercontinental spread of the mcr-1 gene.

Escherichia coli carrying IncX4 plasmid-mediated mcr-1 and blaCTX-M genes in infected migratory Magellanic penguins (Spheniscus magellanicus).

Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of S~ ao Paulo, S~ ao Paulo, Brazil; Department of Clinical Analysis, Faculty of Pharmaceutical Sciences, University of S~ ao Paulo, S~ ao Paulo, Brazil; Department of Pathology, School of Veterinary Medicine and Animal Science, University of S~ ao Paulo, S~ ao Paulo, Brazil; Veterinary Unit of Santos Aquarium, Santos, Brazil; Department of Microbiology, Institute of Biomedical Sciences, University of S~ ao Paulo, S~ ao Paulo, Brazil

Chicken Meat as a Reservoir of Colistin-Resistant Escherichia coli Strains Carrying mcr-1 Genes in South America

ABSTRACT The detection and rapid spread of colistin-resistant Enterobacteriaceae carrying the mcr-1 gene has created an urgent need to strengthen surveillance. In this study, eight clonally unrelated colistin-resistant Escherichia coli isolates carrying mcr-1 and blaCTX-M or blaCMY-2 genes were isolated from commercial chicken meat in Brazil. Most E. coli strains carried IncX4 plasmids, previously identified in human and animal isolates. These results highlight a new reservoir of mcr-1-harboring E. coli strains in South America.

Colistin-Resistant mcr-1-Positive Escherichia coli on Public Beaches, an Infectious Threat Emerging in Recreational Waters

ABSTRACT The emergence and rapid spread of colistin-resistant Escherichia coli carrying the mcr-1 gene have generated an urgent need to strengthen surveillance. We performed a meticulous investigation of strains of this sort, which resulted in the identification of international clones of E. coli carrying IncX4-plasmid-mediated mcr-1 and blaCTX-M genes in recreational waters of public urban beaches in cities with high tourist turnover, highlighting a new environmental reservoir.

Detection of Colistin-Resistant MCR-1-Positive Escherichia coli by Use of Assays Based on Inhibition by EDTA and Zeta Potential

ABSTRACT The emergence and rapid dissemination of colistin-resistant Escherichia coli carrying the plasmid-mediated mcr-1 gene have created an urgent need to develop specific screening methods. In this study, we evaluated four assays based on the inhibition of MCR-1 activity by EDTA: (i) a combined-disk test (CDT) comparing the inhibition zones of colistin and colistin (10 μg) plus EDTA (100 mM); (ii) reduction of colistin MIC (CMR) in the presence of EDTA (80 μg/ml); (iii) a modified rapid polymyxin Nordmann/Poirel test (MPNP); and (iv) alteration of zeta potential (RZP = ZP+EDTA/ZP−EDTA). We obtained encouraging results for the detection of MCR-1 in E. coli isolates recovered from human, food, and animal samples, using the following assay parameters: ≥3 mm difference in the inhibition zones between colistin disks without and with EDTA; ≥4-fold colistin MIC decrease in the presence of EDTA; RZP of ≥2.5; and the absence of metabolic activity and proliferation, indicated by unchanged color of phenol red in the presence of colistin-EDTA, in the MPNP test. In this regard, the CDT, CMR, RZP, and MPNP assays exhibited sensitivities of 96.7, 96.7, 95.1, and 96.7% and specificities of 89.6, 83.3, 100, and 100%, respectively, for detecting MCR-1-positive E. coli. Our results demonstrate that inhibition by EDTA and zeta potential assays may provide simple and inexpensive methods for the presumptive detection of MCR-1-producing E. coli isolates in human and veterinary diagnostic laboratories.

Virulent nontyphoidal Salmonella producing CTX-M and CMY-2 β-lactamases from livestock, food and human infection, Brazil.

Qu ezia Moura, Miriam R. Fernandes, Ketrin C. Silva, Daniel F. Monte, Fernanda Esposito, Milena Dropa, C esar Noronha, Andrea M. Moreno, Mariza Landgraf, F abio J. Negr~ao, and Nilton Lincopan a,b Department of Microbiology, Institute of Biomedical Sciences, Universidade de S~ao Paulo, S~ao Paulo, Brazil; Department of Clinical Analysis, School of Pharmacy, Universidade de S~ao Paulo, S~ao Paulo, Brazil; School of Veterinary Medicine, Universidade de S~ao Paulo, S~ao Paulo, Brazil; Food and Experimental Nutrition Department, School of Pharmacy & Food Research Center, Universidade de S~ao Paulo, S~ao Paulo, Brazil; Public Health Laboratory, School of Public Health, Universidade de S~ao Paulo, S~ao Paulo, Brazil; State Center for Clinical Analysis, S~ao Paulo, S~ao Paulo, Brazil; Health Sciences Research Laboratory, School of Health Sciences, Universidade Federal da Grande Dourados, Dourados, Brazil

Changed epidemiology during intra and interhospital spread of high-risk clones of vanA-containing Enterococcus in Brazilian hospitals

We report changes in the molecular epidemiology of vanA-containing Enterococcus during the intra and interhospital spread of high-risk clones, in Southeastern Brazil. While VRE faecalis predominated during 1998 to 2006, a reversal has been observed in the last years, where VRE faecium belonging to ST114, ST203, ST412, ST478 and ST858 have become endemic.

Microbicidal gentamicin-alginate hydrogels

Sodium alginate (Alg) reacted with antibiotic gentamicin sulfate (GS) in an aqueous-phase condition mediated by carbodiimide chemistry, in the molar ratios Alg: GS of (1:0.5), (1:1) and (1:2). The Alg-GS conjugated derivatives were characterized by elemental analysis for nitrogen content, Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analyses (TGA) and water sorption measurements. XPS and FTIR-ATR analyses clearly indicated that GS molecules covalently attached to the backbone of the alginate chains by amide bond formation. The highest amount of GS bound to Alg (43.5 ± 0.4 wt%) and the highest swelling ratio (4962 ± 661%) were observed for the Alg-GS (1:2) sample. Bioluminescence assays with Pseudomonas aeruginosa PAO1/lecA:lux and colony forming counting of Staphylococcus aureus and Escherichia coli upon contact with all Alg-GS conjugates revealed microbicidal activity; however, Alg-GS (1:2) was the most efficient, due to the highest GS content.

Authors' reply: Escherichia coli harbouring mcr-1 gene isolated from poultry not exposed to polymyxins in Brazil.

To the editor: The foregoing letter by Lentz et al. examined the occurrence of the mcr-1 gene in Escherichia coli isolates recovered from chicken cloacal swabs collected between August and October of 2015, from a poultry slaughterhouse in southern Brazil [1], providing valuable additional data on the epidemiology of this novel gene. Of 343 animals screened, 10 (3%) different chickens belonging to three flocks from three different breeders were found with mcr-1 positive E. coli isolates [1]. None of these chickens had been reportedly exposed to polymyxins (as growth promoter) [1]. The authors therefore considered their findings as contradicting the plausible hypothesis that the emergence of the mcr-1 gene is linked to the use of polymyxins in animal feed in Brazilian livestock [2], suggesting that others compounds or factors may also be involved in the selection of this gene.