Sensitivity of Argentinean isolates of Leptosphaeria maculans to azoxystrobin, boscalid and prothioconazole

Phytophthora austrocedri is causing widespread mortality of Austrocedrus chilensis in Argentina and Juniperus communis in Britain. The pathogen has also been isolated from J. horizontalis in Germany. Isolates from Britain, Argentina, and Germany are homothallic, with no clear differences in the dimensions of sporangia, oogonia, or oospores. Argentinian and German isolates grew faster than British isolates across a range of media and had a higher temperature tolerance, although most isolates, regardless of origin, grew best at 15°C and all isolates were killed at 25°C. Argentinian and British isolates caused lesions when inoculated onto both A. chilensis and J. communis; however, the Argentinian isolate caused longer lesions on A. chilensis than on J. communis and vice versa for the British isolate. Genetic analyses of nuclear and mitochondrial loci showed that all British isolates are identical. Argentinian isolates and the German isolate are also identical but differ from the British isolates. Single-nucleotide polymorphisms are shared between the British and Argentinian isolates. We concluded that British isolates and Argentinian isolates conform to two distinct clonal lineages of P. austrocedri founded from the same as-yet-unidentified source population. These lineages should be recognized and treated as separate risks by international plant health legislation.

Strawberry mild yellow edge virus (SMYEV) has been detected in most of the strawberry production regions worldwide. However, little is known about differences between distinct isolates. The aim of this study was to enhance the knowledge about the genetic variability of different SMYEV isolates, exploring the phylogenetic relationships and assessing recombinant events among them. The coat protein (CP) gene of 12 Argentinian SMYEV isolates was sequenced. There were 729 nucleotides (nt) in all of the isolates, encoding a protein of 242 amino acids (aa). Argentina isolates shared 81.5–99.6 % nucleotide identity. The comparison of these isolates with 30 SMYEV sequences from other countries published in the GenBank, revealed an identity ranging from 81.6 to 99 %. The phylogenetic analysis showed the presence of four possible subgroups, with the Argentinian isolates being included in all of them. Recombination analysis indicated that 16–2 (KP 284155) Argentinian and AJ577342 Chilean isolates are recombinant and that they are a result of recombination events where parts of the genome were exchanged between different SMYEV sequences.

Comparative analysis of replicative properties of phylogenetically divergent, Argentinean BoHV-4 strains in cell lines from different origins.

While the differential association of Escherichia coli O157 genotypes with animal and human hosts has recently been well documented, little is known about their distribution between countries and how this might affect regional disease rates. Here, we used a 48-plex single nucleotide polymorphism (SNP) assay to segregate 148 E. coli O157 isolates from Australia, Argentina, and the United States into 11 SNP lineages. We also investigated the relationship between SNP lineages, Shiga toxin (Stx) gene profiles, and total Stx production. E. coli O157 isolates clearly segregated into SNP lineages that were differentially associated with each country. Of the 11 SNP lineages, seven were detected among isolates from a single country, two were detected among isolates from all three countries, and another two were detected only among U.S. and Argentinean isolates. A number of Australian (30%) and Argentinean (14%) isolates were associated with novel, previously undescribed SNP lineages that were unique to each country. Isolates within SNP lineages that were strongly associated with the carriage of stx2a produced comparatively more Stx on average than did those lacking the stx2a subtype. Furthermore, the proportion of isolates in stx2a-associated SNP lineages was significantly higher in Argentina and the United States than Australia (P < 0.05). This study provides evidence for the geographic divergence of E. coli O157 and for a prominent role of stx2a in total Stx production. These results also highlight the need for more comprehensive studies of the global distribution of E. coli O157 lineages and the impacts of regionally predominant E. coli O157 lineages on the prevalence and severity of disease.

We report the nucleotide sequence and genetic diversity of four Equine Arteritis Virus (EAV) ORF 5 and 6 from Argentina isolates, obtained from asymptomatic virus-shedding stallions. Nucleic acid recovered from the isolates were amplified by RT-PCR and sequenced. Nucleotide and deduced amino acid sequences from the Argentine isolates were compared with 17 sequences available from the GenBank. Phylogenetic analysis revealed that the Argentine isolates grouped together in a definite cluster near European strains. Despite the greater genetic variability among ORF 5 from different isolates and strains of EAV, phylogenetic trees based on ORF 5 and 6 are similar. Both trees showed that virus sequences from America and Europe segregate into distinct clades based on sequence analysis of either ORF 5 or 6. This study constitutes the first characterization of Argentine EAV isolates.

Chicken infectious anemia virus (CAV) is a worldwide-distributed infectious agent that affects commercial poultry. Although this agent was first detected in Argentina in 1994, no further studies on CAV in this country were reported after that. The recent increased occurrence of clinical cases of immunosuppression that could be caused by CAV has prompted this study. Our results confirmed that CAV is still circulating in commercial flocks in Argentina. Phylogenetic analysis focusing on the VP1 nucleotide sequence showed that all Argentinean isolates grouped together in a cluster, sharing a high similarity (> 97%) with genotype B reference strains. However, Argentinean isolates were distantly related to other strains commonly used for vaccination in this country, such as Del-Ros and Cux-1. Sequence analysis of predicted VP1 peptides showed that most of the Argentinean isolates have a glutamine residue at positions 139 and 144, suggesting that these isolates might have a reduced spread in cell culture compared with Cux-1. In addition, a particular amino acid substitution at position 290 is present in all studied Argentinean isolates, as well as in several VP1 sequences from Malaysia, Australia, and Japan isolates. Our results indicate that it is possible to typify CAV strains by comparison of VPI nucleotide sequences alone because the same tree topology was obtained when using the whole genome sequence. The molecular analysis of native strains sheds light into the epidemiology of CAV in Argentinean flocks. In addition, this analysis could be considered in future control strategies focused not only on breeders but on broilers and layer flocks.

Brazil and Argentina have a combined soybean area of 53.6 million hectares, which accounts for over half of the total global production. The soybean crop in South America extends from latitude 8–10° S to 32–36° S. Such a vast, almost contiguous area imposes a serious sanitary risk to the crop. Currently, the prevalence of anthracnose is increasing, with recurring reports of severe epidemics and expressive yield losses. Soybean anthracnose is mainly associated with Colletotrichum truncatum, although other Colletotrichum species have also been reported as causal agents of this disease. Knowledge about the morphological, cultural, and molecular variability of C. truncatum in South America is crucial for disease management. Here, we present data on the molecular, morphological, biological, cultural, and pathogenicity of C. truncatum isolates collected in Brazil and Argentina. Light microscopy and randomly-amplified polymorphic DNA (RAPD) analysis were used for estimating the variability of isolates. Colletotrichum truncatum displayed three types of conidiogenesis, viz. conidial formation from conidiogenous cells on hyphal extremities, in conidiomas in acervuli, and directly from fertile setae (a mechanism yet-unreported for C. truncatum). RAPD profiling was effective in revealing the genetic diversity among C. truncatum isolates. The intra-group similarity was greater among the Argentinian isolates when compared to the Brazilian group. Furthermore, the results indicated a strong correlation between geographical origin and molecular grouping, with the exclusive or semi-exclusive assembling of Brazilian and Argentinian isolates in distinct clades. Finally, a preliminary account of the reaction of soybean accessions to C. truncatum is also included.

BackgroundMost MSSA harbor one of the four different variants of β-lactamase (BlaZ) (A, B, C and D). The CIE is defined as an MIC >16 μg/mL when a high inoculum (107 CFU/mL) is used and depends on the presence of BlaZ. The presence of the CIE has been associated with therapeutic failure in invasive MSSA infections. In some countries of South America, the prevalence of CIE is high, ranging from 36% to 51% (Colombia and Argentina, respectively). Type A BlaZ is most often associated with the CIE due to its high affinity for cefazolin. Here, we developed a rapid test based on the premise that the extracellular form of BlaZ is responsible for the CIE. We aimed to identify invasive MSSA that exhibit the CIE and validate the test in two cohorts of isolates from patients in Colombia and ArgentinaMethods152 MSSA clinical isolates were collected from Colombia (n = 71) and Argentina (n = 81). We determined MIC at standard and high inoculum. We developed a test using induction of BlaZ with ampicillin (150 μg/mL) for 20 minutes and, using the supernatant for incubation with nitrocefin for 30 min. A change in color from yellow to red was considered positive. MSSA TX0117 (BlaZ +, with the CIE), ATCC 29213 (BlaZ-negative) and ATCC 25923 (BlaZ + lacking the CIE) were used as controls. BlaZ typing of all Argentinian isolates was available by sequencingResultsA high proportion (43%) of MSSA exhibited the CIE (34% and 52% of Colombian and Argentinian isolates, respectively) by MIC. The rapid test identified 76% of isolates exhibiting the CIE and correctly ruled out all isolates lacking the CIE (sensitivity 80%, specificity 100%). Furthermore, the rapid test detected all isolates with the CIE that harbored Type A BlaZ from Argentina. Conversely, the test failed to identify the CIE in Argentinian isolates that produce type B and C BlaZ. The sensitivity and specificity of the rapid test for the Colombian isolates whose BlaZ type was unknown were 89% and 100%, respectively.ConclusionA rapid test of less than 2 h can readily identify MSSA isolates exhibiting the CIE. For isolates carrying type A BlaZ, which is highly associated with the CIE, the test had a sensitivity and specificity of 100%. Rapid identification of MSSA with the CIE may have important therapeutic consequences in deep-seated infectionsDisclosuresAll authors: No reported disclosures.

Staphylococcus pseudintermedius is the most common opportunistic pathogen in dogs and methicillin resistance (MRSP) has been identified as an emerging problem in canine pyoderma. Here, we evaluated the antimicrobial resistance (AMR) features and phylogeny of S. pseudintermedius isolated from canine pyoderma cases in Argentina (n = 29) and the United States (n = 29). 62% of isolates showed multi-drug resistance. The AMR genes found: mecA, blaZ, ermB, dfrG, catA, tetM, aac(6')-aph(2″), in addition to tetK and lnuA (only found in U.S. isolates). Two point mutations were detected: grlA(S80I)-gyrA(S84L), and grlA(D84N)-gyrA(S84L) in one U.S. isolate. A mutation in rpoB (H481N) was found in two isolates from Argentina. SCCmec type III, SCCmec type V, ΨSCCmec57395 were identified in the Argentinian isolates; and SCCmec type III, SCCmec type IVg, SCCmec type V, and SCCmec type VII variant in the U.S. cohort. Sequence type (ST) ST71 belonging to a dominant clone was found in isolates from both countries, and ST45 only in Argentinian isolates. This is the first study to comparatively analyze the population structure of canine pyoderma-associated S. pseudintermedius isolates in Argentina and in the U.S. It is important to maintain surveillance on S. pseudintermedius populations to monitor AMR and gain further understanding of its evolution and dissemination.

Hepatitis E virus (HEV) has been identified in 2 Argentine patients with acute hepatitis who reported no history of travel to regions in which HEV is considered endemic. These isolates are the first to be identified in South America. By use of degenerate primers from open reading frames 1 and 2, HEV sequences were obtained from these patients' serum and compared with published HEV sequences. The Argentine isolates are different from all previously identified HEV isolates and are most closely related to each other. The Argentine isolates are distinct from the most geographically related isolate from Mexico as well as isolates from other endemic (China, Southeast Asia, and India) and nonendemic (the United States and Europe) regions. Phylogenetic analysis indicate that the Argentine isolates represent a new genotype of HEV, genotype 8, distinct from the Burmese-like genotype 1, Mexican genotype 2, US genotype 3, Chinese/Taiwan genotype 4, and European genotypes 5-7.

Trypanosoma (Schizotrypanum) cruzi: repetitive DNA sequence evolution in three geographically distinct isolates

Wheat streak mosaic virus (WSMV) was first detected in Argentina in 2002. Comparison of 78 WSMV coat protein sequences revealed that three Argentine isolates were closely related to isolates from the American Pacific Northwest (APNW) and Australia. Complete sequences were determined for one Argentine isolate, four APNW isolates, and three additional isolates from other regions of the USA. Comparison of these eight new sequences with five previously sequenced isolates of WSMV confirmed close affinity of WSMV from Argentina with APNW isolates. Collectively, these results indicate concurrent establishment of the same WSMV lineage in both Argentina and Australia.

First finding of genetic and antigenic diversity in 1b-BVDV isolates from Argentina

Fungicide resistance in <i>Cercospora</i> species causing cercospora leaf blight and purple seed stain of soybean in Argentina

During the 2018 growing season, cotton plants in several fields in Georgia were observed with symptoms that included leaf curling, reddening and drooping of leaves, subsequent distortion of leaf growth above the nodes where reddened leaves were first observed, and shortening of upper internodes and their discoloration to deep green. These symptoms were visible in the upper portion of the plants, resembling “cotton blue” disease caused by cotton leafroll dwarf virus (CLRDV) (family Luteoviridae, genus Polerovirus). The symptoms were observed sporadically with less than 10% disease incidence within affected fields. CLRDV is a phloem-limited virus with single-stranded, positive-sense RNA genome, transmitted by aphids (Aphis gossypii) in a persistent, circulative, nonpropagative manner (Distefano et al. 2010; Sharman et al. 2015). A total of 93 symptomatic and asymptomatic leaves and petioles were collected from several different commercial cotton fields in the southern part of the state. Total RNA was extracted using the modified cetyltrimethylammonium bromide method (Sharman et al. 2015). Complementary DNA (cDNA) was synthesized from 2.5 µg of total RNA using Superscript III reverse transcription (Invitrogen, U.S.A.) and specific reverse primers targeting different open reading frames (ORFs) of the virus genome. The cDNA was used for polymerase chain reaction (PCR) with primers CLRDV3675F and Pol3982R targeting ORF 3 of the virus (310-bp product, Sharman et al. 2015) and primers 17 and 18 targeting ORF 5 (1,065-bp product, Distefano et al. 2010). A new set of primers, SB11F (5′-AGGTTTTCTGGTAGCAGTACCAATATCAACGTTA-3′) and SB11R (5′-TATCTTGCATTGTGGATTTCCCTCATAA-3′), was developed to amplify the 803-bp fragment spanning complete ORF 3 and ORF 4, encoding virus coat protein and movement protein genes. Using the three different sets of primers, products of predicted sizes were amplified from the symptomatic tissues, but not from asymptomatic tissues collected from fields and negative controls including asymptomatic leaves from plants grown in an insect-free controlled growth chamber and DNase/RNase free water (Invitrogen). Reverse transcription PCR products were gel purified, cloned into TOPO-TA cloning vector (Invitrogen), and sequenced using Sanger sequencing (GeneScript, NJ). The consensus sequence of three clones for ORF 3 and 4 from this study (MK290759 and MK290760) when analyzed using NCBI-BLASTn showed 97% sequence identity with the Brazilian and Argentinean isolates (KF906261.1 and KF359947.1, respectively) and many other isolates from South American and Asian countries. ORF 3 and 4 sequences from Georgia shared 98 to 99% identity among themselves. The partial sequences for ORF 5 (MK513938 and MK513939) shared 95% identity with the isolate from Argentina (KF359946.1 and KF359947.1). The presence of the virus was detected in all the symptomatic samples collected from 14 counties in Georgia, covering the entire cotton growing region of the state. To the best of our knowledge, this is the first report of CLRDV in Georgia, U.S.A. CLRDV infection of cotton has been reported in other cotton-growing regions in Africa, Asia, South America, and, more recently, in Alabama, U.S.A. (Avelar et al. 2018; Correa et al. 2005; Distefano et al. 2010; Mukherjee et al. 2012). With its rapid spread, this virus could pose an imminent threat and cause severe economic losses to the cotton industry. Further research is needed to elucidate epidemiology, symptomatology, vector transmission, and crop losses owing to CLRDV in the United States.