Search

Haemosporidian parasites of birds are found worldwide and include the genera Haemoproteus , Plasmodium and Leucocytozoon. Infection with haemosporidian parasites can affect host physical condition and reproductive success. The aim of this study was to identify the blood parasites and parasitaemia in endemic and non-endemic passerine birds from central Mexico highlands. This study included 157 passerines representing 29 species from 17 families. Overall, 30.6% (48/157) of the birds were infected with blood parasites. Of those, Haemoproteus spp. were found in 14.0% (n = 22), Leucocytozoon spp. 12.1% (n = 19) and microfilariae 0.6% (n = 1). Blood parasites were found in 71.4% (5/7) of endemic bird species and 45.4% (10/22) of non-endemic species. Medium to high parasitaemia (number of parasites/number erythrocytes) was observed in birds with infections of Haemoproteus spp. and Leucocytozoon spp. Co-infections 3.8% (n = 6) were observed in two species of endemic birds. This study contributes to the knowledge of haemoparasites in endemic and non-endemic passerine birds from central Mexico highlands. Additional investigation on the molecular identification of haemosporidian parasites, pathogenicity and health status of these birds is necessary. Triple infection: Haemoproteus spp. (Image 2), Leucocytozoon spp. (Image 3), and microfilaria (➤) parasites (A) of a Catharus occidentalis (B). Photomicrographs. Scale-bar : 10 μm. Image 1 • This is the second recorded study of haemoparasites of endemic passerine birds from central Mexico highlands. • Of the 157 birds, 48 birds (30.6%) were infected with blood parasites. • In the birds it was identified Haemoproteus spp. 14.0%, Leucocytozoon spp. 12.1% and microfilariae 0.6%. • Medium to high parasitemia was observed of Haemoproteus spp. and Leucocytozoon spp. • Co-infections were observed in 3.8% (6/157) of all infected birds. [ABSTRACT FROM AUTHOR]

The members of the Aeromonas genus are important foodborne pathogens, with a worldwide distribution. Wild rainbow trout, from the national protected area Santuario del Agua State Park, Corral de Piedra, were analyzed. Species of Aeromonas were isolated from the trout, and their pathogenic potential was analyzed based on different pathogenicity and virulence factors. The isolates were identified as A. allosaccharophila (n = 15), A. sobria (n = 8), A. veronii (n = 3), A. rivipollensis (n = 2), A. piscicola (n = 2), and A. popoffii (n = 1), by RNA polymerase sigma factor (rpoD) gene sequencing. Sequence similarity with the type strain was 92.2 to 99.6% for A. sobria isolates, 97.8 to 98.0% for A. allosaccharophila isolates, 99.2% for the A. popoffii isolate, 99.2 to 100% for A. piscicola isolates, and 98.2 to 99.2% for A. veronii isolates. Notably, isolates A30T2–gills and A30T2–spleen showed sequence similarity of 98.0% with strain A. media CECT 4232T and 99.0% with strain A. rivipollensis P2G1T. Virulence genes were detected by PCR at the following frequencies: fla and serine protease, 96.77%; aerA, 93.54%; aexT, 87.09%; lipases, 74.19%; ascV and ahyB, 67.74%; exu, 61.29%; act, 41.93%; ascF-G, 38.70%; lafA, 32.26%; alt, 6.46%; aopP, 9.67%; and ast, 3.23%. These results indicate that several Aeromonas species had the potential pathogenicity to infect wild rainbow trout in the waterway created by the Corral de Piedra dam, suggesting they could be an emerging zoonotic pathogen. Different Aeromonas species were isolated from wild rainbow trout. This is the first report of A. rivipollensis in the Americas. Risk exists to the health of the local population that uses this water source. [ABSTRACT FROM AUTHOR]

Meat of bovine origin is one of the major vehicles in the transmission of verotoxigenic Escherichia coli (VTEC) to human consumers. This pathogen can produce serious human illness, including bloody diarrhea and hemolytic uremic syndrome. The aim of the current study was to characterize E. coli isolates (mainly VTEC strains) belonging to several serotypes in samples from cattle carcasses and feces of three municipal slaughter plants from Mexico State. The genetic diversity and molecular relatedness among the isolates was evaluated with multiple-locus variable-number tandem repeat analysis (MLVA). To our knowledge, and with the exception of E. coli O157:H7, this is the first time that serotypes analyzed here have been subtyped by MLVA in Mexico. MLVA typing grouped the 37 strains from this study into 30 distinct genotypes, 26 of which were unique. These findings indicate that cattle carcasses and feces from slaughter plants in Mexico are a source of VTEC that are genetically diverse in terms of serotypes and virulence profiles. The presence of these pathogens in carcasses indicates the high probability of the spread of VTEC strains during slaughter and processing. [ABSTRACT FROM AUTHOR]

Healthy lambs are one of the major reservoirs of Shiga toxin-producing Escherichia coli (STEC) and it is known as the cause of foodborne diseases (FBD). The work objective is to characterize (STEC) isolates obtained from rectal swabs of healthy lambs herds, a total of 183 samples were obtained from sheep production units of the State of Mexico. E. coli isolates were confirmed through the amplification of the uid A gene. antimicrobial sensitivity pattern was determined through Kirby-Bauer ( CLSI, 2012 ) test and the presence stx 1 , stx 2 and eae genes from isolates by multiplex PCR. Serotyping was performed using specific anti-O and anti-H sera (SERUNAM, Mexico) for 185 Somatic and 56 flagellar antigens. 126 isolates biochemically and molecularly identified as E. coli were obtained, of which 80 did not express any virulence factor and 46 expressed at least some (STEC) virulence factor. The highest percentage of E. coli resistance was for tetracycline 48.7% (39/80), followed by nalidixic acid 13.7% (11/80), gentamicin 6.2% (5/80) and Ciprofloxacin 3.7% (3/80). Resistance to amikacin, cefotaxime and ceftazidime were not detected. A frequency of 46 STEC isolates (36.2%) were obtained, of which 28/46 (22.0%) expressed stx 1 , stx 2 3/46 (6.5%), stx 1 , stx 2 13/46 (10.2%) and eae 2/46 (1.6%). Thirty different serotypes were obtained. The three serotypes with the highest number of isolates (four each) were: O76:H19, O118:H27 and O146:H21 which have been identified as a cause of diarrhea in human population. An isolate of serogroup O104 was obtained, with a significant importance for European public health. In virtue of the discovered serotypes and the virulence factors distribution, we can affirm that the obtained isolates from lambs in the State of Mexico are classifiable as atypical STEC of low virulence. [ABSTRACT FROM AUTHOR]

The objective of the present study was to determine the in vitro antimicrobial susceptibility of Avibacterium paragallinarum isolates from infectious coryza outbreaks in Dutch commercial poultry, from 2008 till mid-2017. By using a broth microdilution method, minimal inhibitory concentrations (MICs) of 15 antimicrobial agents were assessed, and MIC 50 and MIC 90 values were determined. Additionally, isolates were subjected to different PCRs for the presence of genes that may confer antimicrobial resistance. Besides field isolates, a set of reference strains, among which the nine Kume strains and one Page serovar strain, were included in the study. For broth microdilution testing a new growth medium, recently developed for susceptibility testing of Haemophilus parasuis , was used. The medium proved to be suitable for broth microdilution susceptibility testing of NAD dependent Av. paragallinarum as well; visible growth was obtained in growth control wells and accepting a deviation of one dilution step, MIC values were reproducible. Results of 44 field isolates originating from 25 outbreaks showed relatively good susceptibility to antimicrobial agents that are recommended for the treatment of infectious coryza in the Netherlands, except for tetracycline; circa 75% of the isolates were characterized by MIC values of tetracycline of ≥16 μg/ml. In almost a quarter of these isolates with high MICs of tetracycline, tet genes were detected. For the remaining isolates with elevated MIC values, the mechanism conferring resistance remains to be studied. Of most agents, low MIC values were determined for the nine Kume and one Page serovar reference strains, as well as negative PCR results for resistance genes, being concordant with agar diffusion results reported for these strains. [ABSTRACT FROM AUTHOR]

Ten species of Aeromonas have been previously identified in farmed rainbow trout from Mexico. The aim of the current study was to investigate the pathogenicity of 10 Aeromonas isolates belonging to 10 different Aeromonas species in immersion experimentally-infected rainbow trout fry. Isolates of A. bestiarum , A. hydrophila , A. salmonicida , and A. veronii produced significant mortality (8.8%, 12.2%, 18.8%, and 8.8%, respectively). Isolates of A. caviae and A. sobria produced no significantly mortality (3.3% and 1.1%, respectively). No mortality was recorded in fish infected with A. allosaccharophila , A. lusitana , A. media , or A. popoffii . Microscopic lesions and bacterial reisolation were registered in liver of fish infected with the ten different Aeromonas isolates. Our results suggest that all Aeromonas species included in the study have the ability to colonize the liver. The results have confirmed that species A. bestiarum , A. hydrophila , A. salmonicida , and A. veronii affected fish as elsewhere reported. In conclusion, the variation in pathogenicity of Aeromonas isolates included in the study, emphasizes the importance of active, on-going monitoring of Aeromonas in the Mexican rainbow trout farming. [ABSTRACT FROM AUTHOR]

Highlights: [•] Genetic identification of Aeromonas species from rainbow trout in Mexico reported for the first time. [•] Comparison of phenotypic and genetic identification in a number id Aeromonas isolates. [•] Isolation of Aeromonas from internal organs and lesions, indicating its pathogenic potential. [•] Low antimicrobial resistance trend among studied Aeromonas isolates. [ABSTRACT FROM AUTHOR]