MALDI-TOF MS-Based KPC Direct Detection from Patients' Positive Blood Culture Bottles, Short-Term Cultures, and Colonies at the Hospital.

Carbapenemase resistance in Enterobacterales is a global public health problem and rapid and effective methods for detecting these resistance mechanisms are needed urgently. Our aim was to evaluate the performance of a MALDI-TOF MS-based "Klebsiella pneumoniae carbapenemase" (KPC) detection protocol from patients' positive blood cultures, short-term cultures, and colonies in healthcare settings. Bacterial identification and KPC detection were achieved after protein extraction with organic solvents and target spot loading with suitable organic matrices. The confirmation of KPC production was performed using susceptibility tests and blaKPC amplification using PCR and sequencing. The KPC direct detection (KPC peak at approximately 28.681 Da) from patients' positive blood cultures, short-term cultures, and colonies, once bacterial identification was achieved, showed an overall sensibility and specificity of 100% (CI95: [95%, 100%] and CI95: [99%, 100%], respectively). The concordance between hospital routine bacterial identification protocol and identification using this new methodology from the same extract used for KPC detection was ≥92%. This study represents the pioneering effort to directly detect KPC using MALDI-TOF MS technology, conducted on patient-derived samples obtained from hospitals for validation purposes, in a multi-resistance global context that requires concrete actions to preserve the available therapeutic options and reduce the spread of antibiotic resistance markers.

Feeding on soybean crops changed gut bacteria diversity of the southern green stinkbug (Nezara viridula) and reduced negative effects of some associated bacteria.

BACKGROUND: The southern green stinkbug (Nezara viridula) is a mayor pest of soybean. However, the mechanism underlying stinkbug resistance to soybean defenses is yet ignored. Although gut bacteria could play an essential role in tolerating plant defenses, most studies testing questions related to insect-plant-bacteria interactions have been performed in laboratory condition. Here we performed experiments in laboratory and field conditions with N. viridula and its gut bacteria, studying gut lipid peroxidaxion levels and cysteine activity in infected and unifected nymphs, testing the hypothesis that feeding on field-grown soybean decreases bacterial abundance in stinkbugs. RESULTS: Gut bacterial abundance and infection ratio were higher in N. viridula adults reared in laboratory than in those collected from soybean crops, suggesting that stinkbugs in field conditions may modulate gut bacterial colonization. Manipulating gut microbiota by infecting stinkbugs with Yokenella sp. showed that these bacteria abundance decreased in field conditions, and negatively affected stinkbugs performance and were more aggressive in laboratory rearing than in field conditions. Infected nymphs that fed on soybean pods had lower mortality, higher mass and shorter development period than those reared in the laboratory, and suggested that field conditions helped nymphs to recover from Yokenella sp. infection, despite of increased lipid peroxidation and decreased cysteine proteases activity in nymphs' guts. CONCLUSIONS: Our results demonstrated that feeding on field-grown soybean reduced bacterial abundance and infection in guts of N. viridula and highlighted the importance to test functional activities or pathogenicity of microbes under realistic field conditions prior to establish conclusions on three trophic interactions. © 2022 Society of Chemical Industry.

Phenotypic Detection of Plasmid-Mediated Colistin Resistance in Enterobacteriaceae.

The aim of this work was to evaluate an easy-to-perform assay based upon inhibition of mobile colistin resistance (MCR) activity by EDTA. We included 92 nonrelated isolates of Enterobacteriaceae (74 Escherichia coli, 17 Klebsiella pneumoniae, and 1 Serratia marcescens). Our proposed method is based on a modification of the colistin agar-spot screening test (CAST), a plate containing 3 µg/ml colistin, by adding an extra plate of colistin agar-spot supplemented with EDTA (eCAST). Bacterial growth was evaluated after 24 h of incubation at 35°C. All the colistin-resistant isolates showed development on the CAST plates. Colistin-resistant K. pneumoniae without mcr-1 and S. marcescens also grew on the eCAST plates. In contrast, colistin-resistant MCR-producing E. coli was not able to grow in eCAST plates. The combined CAST/eCAST test could provide a simple and easy-to-perform method to differentiate MCR-producing Enterobacteriaceae from those in which colistin resistance is mediated by chromosomal mechanisms.

Simultaneous Carriage of mcr-1 and Other Antimicrobial Resistance Determinants in Escherichia coli From Poultry.

The use of antimicrobial growth promoters (AGPs) in sub-therapeutic doses for long periods promotes the selection of resistant microorganisms and the subsequent risk of spreading this resistance to the human population and the environment. Global concern about antimicrobial resistance development and transference of resistance genes from animal to human has been rising. The goal of our research was to evaluate the susceptibility pattern to different classes of antimicrobials of colistin-resistant Escherichia coli from poultry production systems that use AGPs, and characterize the resistance determinants associated to transferable platforms. E. coli strains (n = 41) were obtained from fecal samples collected from typical Argentine commercial broiler farms and susceptibility for 23 antimicrobials, relevant for human or veterinary medicine, was determined. Isolates were tested by PCR for the presence of mcr-1, extended spectrum ß-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) coding genes. Conjugation and susceptibility patterns of the transconjugant studies were performed. ERIC-PCR and REP-PCR analysis showed a high diversity of the isolates. Resistance to several antimicrobials was determined and all colistin-resistant isolates harbored the mcr-1 gene. CTX-M-2 cefotaximase was the main mechanism responsible for third generation cephalosporins resistance, and PMQR determinants were also identified. In addition, co-transference of the qnrB determinant on the mcr-1-positive transconjugants was corroborated, which suggests that these resistance genes are likely to be located in the same plasmid. In this work a wide range of antimicrobial resistance mechanisms were identified in E. coli strains isolated from the environment of healthy chickens highlighting the risk of antimicrobial abuse/misuse in animals under intensive production systems and its consequences for public health.

Characterized non-transient microbiota from stinkbug (Nezara viridula) midgut deactivates soybean chemical defenses.

The Southern green stinkbug (N. viridula) feeds on developing soybean seeds in spite of their strong defenses against herbivory, making this pest one of the most harmful to soybean crops. To test the hypothesis that midgut bacterial community allows stinkbugs to tolerate chemical defenses of soybean developing seeds, we identified and characterized midgut microbiota of stinkbugs collected from soybean crops, different secondary plant hosts or insects at diapause on Eucalyptus trees. Our study demonstrated that while more than 54% of N. viridula adults collected in the field had no detectable bacteria in the V1-V3 midgut ventricles, the guts of the rest of stinkbugs were colonized by non-transient microbiota (NTM) and transient microbiota not present in stinkbugs at diapause. While transient microbiota Bacillus sp., Micrococcus sp., Streptomyces sp., Staphylococcus sp. and others had low abundance, NTM microbiota was represented by Yokenella sp., Pantoea sp. and Enterococcus sp. isolates. We found some isolates that showed in vitro ß-glucosidase and raffinase activities plus the ability to degrade isoflavonoids and deactivate soybean protease inhibitors. Our results suggest that the stinkbugs´ NTM microbiota may impact on nutrition, detoxification and deactivation of chemical defenses, and Enterococcus sp., Yokenella sp. and Pantoea sp. strains might help stinkbugs to feed on soybean developing seeds in spite of its chemical defenses.

Primer relevamiento de marcadores de resistencia a antibióticos en Enterobacteriaceae en Cochabamba, Bolivia / First survey on antibiotic resistance markers in Enterobacteriaceae in Cochabamba, Bolivia

A molecular survey was conducted in Cochabamba, Bolivia, to characterize the mechanism involved in the resistance to clinically relevant antibiotics. Extended Spectrum β-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) markers were investigated in a total of 101 oxyimino-cephalosporin-resistant enterobacteria recovered from different health centers during four months (2012-2013). CTX-M enzymes were detected in all isolates, being the CTX-M-1 group the most prevalent (88.1%). The presence of blaOXA-1 was detected in 76.4% of these isolates. A high quinolone resistance rate was observed among the included isolates. The aac(6′)-Ib-cr gene was the most frequent PMQR identified (83.0%). Furthermore, 6 isolates harbored the qnrB gene. Interestingly, qepA1 (6) and oqxAB (1), were detected in 7 Escherichia coli, being the latter the first to be reported in Bolivia. This study constitutes the first molecular survey on resistance markers in clinical enterobacterial isolates in Cochabamba, Bolivia, contributing to the regional knowledge of the epidemiological situation. The molecular epidemiology observed herein resembles the scene reported in South America.

Se llevó a cabo un relevamiento molecular de la resistencia a antibióticos de importancia clínica en aislamientos recuperados en Cochabamba, Bolivia. Se estudiaron los genes codificantes de β-lactamasas de espectro extendido y de resistencia a quinolonas de localización plasmídica (PMQR) en un total de 101 aislamientos de enterobacterias resistentes a oximinocefalosporinas recuperados en distintos centros de salud, durante 4 meses (2012-2013). En todos ellos se detectó la presencia de cefotaximasas, las CTX-M grupo 1 fueron las más prevalentes (88,1%). La presencia de blaOXA-1 se detectó en el 76,4% de estos aislamientos. Se observó una elevada proporción de aislamientos resistentes a quinolonas. El gen aac(6′)-Ib-cr fue el determinante PMQR más frecuentemente identificado (83%). Además, 6 aislamientos resultaron ser portadores de qnrB. Por otro lado, cabe remarcar que 7 Escherichia coli presentaron qepA1 (6) y oqxAB (1); se documenta así por primera vez la presencia de oqxAB en Bolivia. Este estudio constituye el primer relevamiento de marcadores de resistencia en aislamientos clínicos de enterobacterias en Cochabamba, Bolivia; de este modo se contribuye al conocimiento regional de la situación epidemiológica, la cual presenta un escenario similar al observado en el resto de Latinoamérica.

First survey on antibiotic resistance markers in Enterobacteriaceae in Cochabamba, Bolivia.

A molecular survey was conducted in Cochabamba, Bolivia, to characterize the mechanism involved in the resistance to clinically relevant antibiotics. Extended Spectrum ß-lactamase encoding genes and plasmid-mediated quinolone resistance (PMQR) markers were investigated in a total of 101 oxyimino-cephalosporin-resistant enterobacteria recovered from different health centers during four months (2012-2013). CTX-M enzymes were detected in all isolates, being the CTX-M-1 group the most prevalent (88.1%). The presence of blaOXA-1 was detected in 76.4% of these isolates. A high quinolone resistance rate was observed among the included isolates. The aac(6')-Ib-cr gene was the most frequent PMQR identified (83.0%). Furthermore, 6 isolates harbored the qnrB gene. Interestingly, qepA1 (6) and oqxAB (1), were detected in 7 Escherichia coli, being the latter the first to be reported in Bolivia. This study constitutes the first molecular survey on resistance markers in clinical enterobacterial isolates in Cochabamba, Bolivia, contributing to the regional knowledge of the epidemiological situation. The molecular epidemiology observed herein resembles the scene reported in South America.

Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC).

Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2 . Strains carrying intl1 belonged to isolates from environment (n = 1), chicken hamburger (n = 2), dairy calves (n = 4) and pigs (n = 8). Two strains isolated from pigs harbored intl2 and only one intl1 / intl2 , highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria.

Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC)

Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic-uremic syndrome in humans (HUS). Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2. Strains carrying intl1 belonged to isolates from environment (n = 1), chicken hamburger (n = 2), dairy calves (n = 4) and pigs (n = 8). Two strains isolated from pigs harbored intl2 and only one intl1/intl2, highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria.

ß-lactamases produced by amoxicillin-clavulanate-resistant enterobacteria isolated in Buenos Aires, Argentina: a new blaTEM gene.

Resistance to ß-lactam/ß-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second- and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed. Sequencing revealed two different variants of blaTEM-1, being blaTEM-1b the most frequently detected allelle (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis and 1 Raoultella terrigena) followed by blaTEM-1a (1 K. pneumoniae). Amoxicillin-clavulanate resistance seems to be mainly associated with TEM-1 overproduction (mostly in E. coli) or co-expressed with OXA-2-like and/or SHV ß-lactamases (K. pneumoniae and P. mirabilis). A new blaTEM variant (TEM-163) was described in an E. coli strain having an AMC MIC value of 16/8µg/ml. TEM-163 contains Arg275Gln and His289Leu amino acid substitutions. On the basis of the high specific activity and low IC50 for clavulanic acid observed, the resistance pattern seems to be due to overproduction of the new variant of broad spectrum ß-lactamase rather than to an inhibitor-resistant TEM (IRT)-like behavior.

ß-lactamases produced by amoxicillin-clavulanate-resistant enterobacteria isolated in Buenos Aires, Argentina: A new blaTEMgene / ß-lactamasas producidas por enterobacterias resistentes a amoxicilina-ácido clavulánico aisladas en Buenos Aires, Argentina: un nuevo gen blaTEM

La resistencia a la combinación de ß-lactámico/inhibidor de ß-lactamasa en enterobacterias es un problema creciente que no ha sido estudiado intensamente en Argentina. En el presente trabajo, 54/843 enterobacterias recolectadas en un hospital universitario de la ciudad de Buenos Aires fueron resistentes a ampicilina-sulbactama, pero se mantuvieron sensibles a las cefalosporinas de segunda y tercera generación. Se analizaron los mecanismos enzimáticos presentes en los aislamientos que también fueron resistentes a amoxicilina-ácido clavulánico (AMC) (18/54). La secuenciación reveló dos variantes diferentes de blaTEM-1, donde blaTEM-1b es el alelo más frecuentemente detectado (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis y 1 Raoultella terrigena), seguidos por blaTEM-1a(1 K. pneumoniae). La resistencia a AMC parece estar asociada principalmente con la hiperproducción de TEM-1 (sobre todo en E. coli) o con la coexpresión con ß-lactamasas tipo OXA-2 y/o SHV (K. pneumoniae y P. mirabilis). Se describió una nueva variante de blaTEM(TEM-163) en un aislamiento de E. coli que presentó una CIM frente a AMC de 16/8 µg/ml. La enzima TEM-163 contiene dos sustituciones de aminoácidos respecto de TEM-1, Arg275Gln y His289Leu. Teniendo en cuenta la alta actividad específica observada y la baja IC50 para el ácido clavulánico, el patrón de resistencia de este aislamiento parece obedecer a la hiperproducción de la nueva variante de la ß-lactamasa de amplio espectro, en lugar de vincularse con un comportamiento similar al de una TEM resistente a inhibidores (IRT).

Resistance to ß-lactam/ß-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second-and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed. Sequencing revealed two different variants of blaTEM-1, being blaTEM-1b the most frequently detected allelle (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis and 1 Raoultella terrigena) followed by blaTEM-1a(1 K. pneumoniae). Amoxicillin-clavulanate resistance seems to be mainly associated with TEM-1 overproduction (mostly in E. coli) or co-expressed with OXA-2-like and/or SHV ß-lactamases (K. pneumoniae and P. mirabilis). A new blaTEMvariant (TEM-163) was described in an E. coli strain having an AMC MIC value of 16/8 µg/ml. TEM-163 contains Arg275Gln and His289Leu amino acid substitutions. On the basis of the high specific activity and low IC50 for clavulanic acid observed, the resistance pattern seems to be due to overproduction of the new variant of broad spectrumß-lactamase rather than to an inhibitor-resistant TEM (IRT)-like behavior.

ß-lactamases produced by amoxicillin-clavulanate-resistant enterobacteria isolated in Buenos Aires, Argentina: A new blaTEMgene / ß-lactamasas producidas por enterobacterias resistentes a amoxicilina-ácido clavulánico aisladas en Buenos Aires, Argentina: un nuevo gen blaTEM

La resistencia a la combinación de ß-lactámico/inhibidor de ß-lactamasa en enterobacterias es un problema creciente que no ha sido estudiado intensamente en Argentina. En el presente trabajo, 54/843 enterobacterias recolectadas en un hospital universitario de la ciudad de Buenos Aires fueron resistentes a ampicilina-sulbactama, pero se mantuvieron sensibles a las cefalosporinas de segunda y tercera generación. Se analizaron los mecanismos enzimáticos presentes en los aislamientos que también fueron resistentes a amoxicilina-ácido clavulánico (AMC) (18/54). La secuenciación reveló dos variantes diferentes de blaTEM-1, donde blaTEM-1b es el alelo más frecuentemente detectado (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis y 1 Raoultella terrigena), seguidos por blaTEM-1a(1 K. pneumoniae). La resistencia a AMC parece estar asociada principalmente con la hiperproducción de TEM-1 (sobre todo en E. coli) o con la coexpresión con ß-lactamasas tipo OXA-2 y/o SHV (K. pneumoniae y P. mirabilis). Se describió una nueva variante de blaTEM(TEM-163) en un aislamiento de E. coli que presentó una CIM frente a AMC de 16/8 Ag/ml. La enzima TEM-163 contiene dos sustituciones de aminoácidos respecto de TEM-1, Arg275Gln y His289Leu. Teniendo en cuenta la alta actividad específica observada y la baja IC50 para el ácido clavulánico, el patrón de resistencia de este aislamiento parece obedecer a la hiperproducción de la nueva variante de la ß-lactamasa de amplio espectro, en lugar de vincularse con un comportamiento similar al de una TEM resistente a inhibidores (IRT).(AU)

Resistance to ß-lactam/ß-lactamase inhibitors in enterobacteria is a growing problem that has not been intensively studied in Argentina. In the present work, 54/843 enterobacteria collected in a teaching hospital of Buenos Aires city were ampicillin-sulbactam-resistant isolates remaining susceptible to second-and third-generation cephalosporins. The enzymatic mechanisms present in the isolates, which were also amoxicillin-clavulanic acid (AMC)-resistant (18/54) were herein analyzed. Sequencing revealed two different variants of blaTEM-1, being blaTEM-1b the most frequently detected allelle (10 Escherichia coli, 3 Klebsiella pneumoniae, 2 Proteus mirabilis and 1 Raoultella terrigena) followed by blaTEM-1a(1 K. pneumoniae). Amoxicillin-clavulanate resistance seems to be mainly associated with TEM-1 overproduction (mostly in E. coli) or co-expressed with OXA-2-like and/or SHV ß-lactamases (K. pneumoniae and P. mirabilis). A new blaTEMvariant (TEM-163) was described in an E. coli strain having an AMC MIC value of 16/8 Ag/ml. TEM-163 contains Arg275Gln and His289Leu amino acid substitutions. On the basis of the high specific activity and low IC50 for clavulanic acid observed, the resistance pattern seems to be due to overproduction of the new variant of broad spectrumß-lactamase rather than to an inhibitor-resistant TEM (IRT)-like behavior.(AU)

First isolate of KPC-2-producing Klebsiella pneumonaie sequence type 23 from the Americas.

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas. Acquisition of resistant markers in virulent clones could mark an evolutionary step toward the establishment of these clones as major nosocomial pathogens.

First detection of CMY-2 plasmid mediated ß-lactamase in Salmonella Heidelberg in South America.

Salmonella enterica serovar Heidelberg ranks among the most prevalent causes of human salmonellosis in the United States and Canada, although it has been infrequently reported in South American and European countries. Most Salmonella infections are self-limiting; however, some invasive infections require antimicrobial therapy. In this work we characterized an oxyimino-cephalosporin resistant S. Heidelberg isolate recovered from an inpatient in a Buenos Aires hospital. CMY-2 was responsible for the ß-lactam resistance profile. S. Heidelberg contained a 97kb plasmid belonging to the Inc N group harboring blaCMY-2. ISEcp1 was located upstream blaCMY-2 driving its expression and mobilization. The isolate belonged to sequence type 15 and virotyping revealed the presence of sopE gene. In this study we identified the first CMY-2 producing isolate of S. Heidelberg in Argentina and even in South America.

Primera detección de CMY-2 en Salmonella Heidelberg en Sudamérica / First detection of CMY-2 plasmid mediated ß-lactamase in Salmonella Heidelberg in South America

Salmonellaenterica serovar Heidelberg es uno de los principales agentes causantes de salmonelosis en humanos en Estados Unidos y Canadá, sin embargo, resulta infrecuente en los países de Sudamérica y Europa. En este trabajo se caracterizó un aislamiento de S. Heidelberg resistente a oximino-cefalosporinas recuperado de un paciente internaen un hospital de la Ciudad de Buenos Aires. Se evidenció la presencia de un plásmido de 97 kbperteneciente al grupo de incompatibilidad IncN, portador del gen blaCMY-2. ISEcp1 fue localizado corriente arriba de blaCMY-2, promoviendo su expresión y movilización.El aislamiento de S. Heidelberg correspondió al secuenciotipo 15 y en la virotipifi cación se detectó el gen sopE. En este trabajo describimos por primera vez la producción de CMY-2 en una cepa de S. Heidelberg en nuestro país y América Latina

Salmonellaenterica serovar Heidelberg ranks among the most prevalent causes of human salmonellosis in the United States and Canada, although it has been infrequently reported in South American and European countries.Most Salmonella infections are self-limiting; however, some invasive infections require antimicrobial therapy. In this work we characterized an oxyimino-cephalosporin resistant S. Heidelberg isolate recovered from an inpatient in a Buenos Aires hospital. CMY-2 was responsible for the ß-lactam resistance profi le. S. Heidelberg contained a 97 kb plasmid belonging to the Inc N groupharboring blaCMY-2. ISEcp1 was located upstream blaCMY-2 driving its expression and mobilization.The isolate belonged to sequence type 15 and virotyping revealed the presence of sopE gene. In this study we identifi ed the fi rst CMY-2 producing isolate of S. Heidelberg in Argentina and even in South Americ