Ketrin C. Silva

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.

Isolation of KPC-2-producing Klebsiella pneumoniae strains belonging to the high-risk multiresistant clonal complex 11 (ST437 and ST340) in urban rivers

Department of Microbiology, Institute of Biomedical Sciences, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Department of Clinical Analysis, School of Pharmacy, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Institute of Biological Sciences, Universidade Federal do Para, Belem, PA, Brazil; School of Public Health, Universidade de Sao Paulo, Sao Paulo, SP, Brazil; Environmental Company of Sao Paulo State (CETESB), Sao Paulo, SP, Brazil

Emergence of Extended-Spectrum-β-Lactamase CTX-M-2-Producing Salmonella enterica Serovars Schwarzengrund and Agona in Poultry Farms

Ketrin C. Silva, Lívia C. Fontes, Andrea M. Moreno, Claudete S. Astolfi-Ferreira, Antonio J. P. Ferreira, Nilton Lincopan Department of Microbiology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil; Department of Preventive Medicine and Animal Health, School of Veterinary Medicine, Universidade de São Paulo, São Paulo, Brazil; Department of Ornitopathology, School of Veterinary Medicine, Universidade de São Paulo, São Paulo, Brazil; School of Pharmacy, Universidade de São Paulo, São Paulo, Brazil

Virulence Profiles, Phylogenetic Background, and Antibiotic Resistance of Escherichia coli Isolated from Turkeys with Airsacculitis

Avian Pathogenic Escherichia coli (APEC) has been studied for decades because of its economic impact on the poultry industry. Recently, the zoonotic potential of APEC and multidrug-resistant strains have emerged. The aim of this study was to characterize 225 APEC isolated from turkeys presenting airsacculitis. The results showed that 92% of strains presented a multidrug-resistance (MDR), and the highest levels of resistance were to sulfamethazine (94%) and tetracycline (83%). Half of these strains were classified in phylogenetic group B2, followed by B1 (28.6%), A (17.1%), and D (4.8%). The prevalence of virulence genes was as follows: salmochelin (iroN, 95%), increased serum survival (iss, 93%), colicin V (cvi/cva, 67%), aerobactin (iucD, 67%), temperature-sensitive haemagglutinin (tsh, 56%), iron-repressible protein (irp2, 51%), invasion brain endothelium (ibeA, 31%), vacuolating autotransporter toxin (vat, 24%), K1 antigen (neuS, 19%), enteroaggregative heat-stable cytotoxin (astA, 17%), and pilus associated with pyelonephritis (papC, 15%). These results demonstrate that the majority of the investigated strains belonged to group B2 and were MDR. These data suggest that turkeys may serve as a reservoir of pathogenic and multidrug-resistance strains, reinforcing the idea that poultry plays a role in the epidemiological chain of ExPEC.

Epidemiologia das betalactamases de espectro estendido no Brasil: impacto clínico e implicações para o agronegócio

The emergence and dissemination of extended-spectrum beta-lactamase bacteria (ESBL) have been reported as a major public health issue, mainly with regard to nosocomial infections. In Brazil, ESBL are widely disseminated among the Enterobacteriaceae family and enzymes TEM, SHV, CTX-M, VEB, BES and GES have been reported in several states. However, the major concern is the high rates of resistant Klebsiella pneumoniae and Escherichia coli strains. Currently, ESBL belonging to CTX-M-2, CTX-M-8 and CTX-M-9 subtypes are the most prevalent in Brazil. Apart from nosocomial infections, ESBL bacteria from outpatient and environmental samples have been identified. CTX-M-2 has been identified in Salmonella samples from animal production, which may have dire consequences for agribusiness, particularly meat export in Brazil. Thus, the regulation of antimicrobial agents is vital in order to avoid the dissemination of multidrug-resistant bacteria and to assure the quality and innocuousness of food products. Therefore, this review aims to report the epidemiology of ESBL in Brazil, focusing on their clinical, environmental and economic impact.

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.

First Characterization of CTX-M-15-Producing Escherichia coli Strains Belonging to Sequence Type (ST) 410, ST224, and ST1284 from Commercial Swine in South America.

ABSTRACT We report for the first time the isolation of CTX-M-15-producing Escherichia coli strains belonging to sequence type (ST) 410, ST224, and ST1284 in commercial swine in Brazil. The blaCTX-M-15 gene was located on F-::A9::B1 and C1::A9::B1 IncF-type plasmids, surrounded by a new genetic context comprising the IS26 insertion sequence truncated with the ISEcp1 element upstream of blaCTX-M-15. These results reveal that commercial swine have become a new reservoir of CTX-M-15-producing bacteria in South America.

Low-virulence phylogenetic background of CTX-M-producing Escherichia coli isolated from extraintestinal infections.

1 Department of Microbiology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil 2 Department of Clinical Analysis, School of Pharmacy, Universidade de São Paulo, São Paulo, Brazil 3 Department of Preventive Medicine and Animal Health, College of Veterinary Medicine, Universidade de São Paulo, São Paulo, Brazil 4 Faculty of Biotechnology, Institute of Biological Sciences, Universidade Federal do Pará, Belém-PA, Brazil 5 Department of Pathology, College of Veterinary Medicine, Universidade de São Paulo, São Paulo, Brazil

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

High-virulence CMY-2- and CTX-M-2-producing avian pathogenic Escherichia coli strains isolated from commercial turkeys

This study reports the high-virulence phylogenetic backgrounds of CMY-2- and CTX-M-2-producing avian pathogenic Escherichia coli strains isolated from turkeys sent to slaughter and condemned by airsacculitis in Brazil. Among 300 air sac samples, seven E. coli strains produced plasmid-mediated CMY-2-type AmpC, of which three carried also the blaCTX-M-2 Extended Spectrum Beta-Lactamase encoding gene. Interestingly, the transfer of the blaCMY-2 gene was positive for three E. coli strains, being associated with the presence of IncI1 plasmids. The complete sequence of the representative pJB10 plasmid revealed that the blaCMY-2 gene was within a transposon-like element in the classical genetic environment consisting of tnpA-blaCMY-2-blc-sugE structure. This plasmid with 94-kb belonged to the sequence type (ST) 12 among IncI1 plasmids, which has been associated with the worldwide spread of blaCMY-2 among Salmonella enterica and E. coli. Furthermore, to the best of our knowledge, this is the first complete sequence of a CMY-2-encoding plasmid derived from an Escherichia coli isolated from food-producing animals in Latin America.