Microbial Characterization of Yellow Curing Process of Codfish

Research articleYellow cured codfish has a typical yellow colour, distinctive taste, and low salt content due to its special curing process of the raw salted codfish involving several soaks in water of the raw salted codfish, alternated with drying steps. The purpose of this study was to assess the main functional groups of bacteria involved in this process and relate them with physicochemical properties of the product. A total of 28 codfish from Iceland were supplied by two local companies. Seven stages of the curing process were analyzed. From each of these seven stages, four fish samples were collected to carry out the microbial and physicochemical analyses (moisture, salt content, pH, total volatile basic nitrogen (TVB-N), and trimethylamine nitrogen (TMA-N)). Bacteria counts were performed using the MPN method and adequate culture media for aerobic, proteolytic, sulphite-reducing, biogenic amine, and trimethylamine-producing and ammonifying bacteria. Strains isolated from the highest dilutions with microbial growth were used to characterize the predominant bacteria. The results showed that total aerobic counts increased from 3.9 log MPN/g in raw salted codfish to 5.9 log MPN/g in the final. Proteolytic, ammonifying, and trimethylamine bacteria producers also increased to 8, 7.5, and 6.5 log MPN/g, respectively. The salt content decreases (from 17% until 8%) and moisture increases (53% until 67%) during the salted-raw-codfish soaking, favoring sulphite-reducing and biogenic amine-producing species, confirming that desalting enhances potential spoilers. The subsequent drying step benefits proteolytic, ammonifying, and trimethylamine-producing bacteria, with a corresponding non-protein-nitrogen content (TVB-N and TMA-N) increase. The dominant bacteria during yellow curing belong to the genera Staphylococcus, Psychrobacter, Pseudomonas, and Alcaligenes with a clear positive correlation between the content of Staphylococcus and Psychrobacter and TVB-N and TMA-N concentration. Staphylococcus spp. are the dominant bacteria in the steps where the product has a higher salt concentration; thus, it could be particularly useful as an indicator to control the industrially yellow curing process and could have an important role in the development of the final characteristics of this productinfo:eu-repo/semantics/publishedVersio

Sympatric threatened Iberian leuciscids exhibit differences in Aeromonas diversity and skin lesions’ prevalence

Funding: This research was supported by CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Project UIDB/00276/2020 (funded by FCT - Fundação para a Ciência e Tecnologia IP) and by MARE (MARE-ISPA), MARE/UIDB/MAR/04292/2020 and strategic project MARE/UIDP/MAR/04292/2020 (also funded by FCT). MLG thanks funding by the University of Lisbon (PhD fellowship C10571K). TAM thanks partial support by CEAUL (funded by FCT, Portugal, through the project UIDB/00006/2020).Assessments regarding health aspects of Iberian leuciscids are limited. There is currently an information gap regarding effects of infectious diseases on these populations and their role as a possible conservation threat. Moreover, differences in susceptibility to particular agents, such as Aeromonas spp., by different species/populations is not clear. To understand potential differences in Aeromonas diversity and load, as well as in the prevalence and proportion of skin lesions, in fishes exposed to similar environmental conditions, an observational study was implemented. Using a set of 12 individuals belonging to two sympatric Iberian leuciscid species (Squalius pyrenaicus and Iberochondrostoma lusitanicum), the skin lesion score in each individual was analyzed. Furthermore, a bacterial collection of Aeromonas spp. isolated from each individual was created and isolates’ load was quantified by plate counting, identified at species level using a multiplex-PCR assay and virulence profiles established using classical phenotypic methods. The similarity relationships of the isolates were evaluated using a RAPD analysis. The skin lesion score was significantly higher in S. pyrenaicus, while the Aeromonas spp. load did not differ between species. When analyzing Aeromonas species diversity between fishes, different patterns were observed. A predominance of A. hydrophila was detected in S. pyrenaicus individuals, while I. lusitanicum individuals displayed a more diverse structure. Similarly, the virulence index of isolates from S. pyrenaicus was higher, mostly due to the isolated Aeromonas species. Genomic typing clustered the isolates mainly by fish species and skin lesion score. Specific Aeromonas clusters were associated with higher virulence indexes. Current results suggest potential differences in susceptibility to Aeromonas spp. at the fish species/individual level, and constitute important knowledge for proper wildlife management through the signalization of at-risk fish populations and hierarchization of conservation measures.Publisher PDFPeer reviewe

Genomic diversity of Oenococcus oeni from different winemaking regions of Portugal

Oenococcus oeni is an alcohol-tolerant, acidophilic lactic acid bacterium that plays an important role in the elaboration of wine. It is often added as a starter culture to carry out malolactic conversion. Given the economic importance of this reaction, the taxonomic structure of this species has been studied in detail. In the present work, phenotypic and molecular approaches were used to identify 121 lactic acid bacteria strains isolated from the wines of three winemaking regions of Portugal. The strains were differentiated at the genomic level by M13-PCR fingerprinting. Twenty-seven genomic clusters represented by two or more isolates and 21 single-member clusters, based on an 85% similarity level, were recognized by hierarchic numerical analysis. M13-PCR fingerprinting patterns revealed a high level of intraspecific genomic diversity in O. oeni. Moreover, this diversity could be partitioned according to the geographical origin of the isolates. Thus, M13-PCR fingerprint analysis may be an appropriate methodology to study the O. oeni ecology of wine during malolactic fermentation as well as to trace new malolactic starter cultures and evaluate their dominance over the native microbiota

In Vivo Effect of a Nisin–Biogel on the Antimicrobial and Virulence Signatures of Canine Oral Enterococci

Research Areas: Infectious Diseases ; Pharmacology & PharmacyABSTRACT - Periodontal disease is a relevant oral disease in dogs and nisin–biogel has been previously proposed to be used in its control. Enterococci, as inhabitants of the oral cavity with a high genetic versatility, are a reliable bacterial model for antimicrobial studies. Our goal was to evaluate the in vivo influence of the long-term dental application of the nisin–biogel on the virulence and antimicrobial signatures of canine oral enterococci. Twenty dogs were randomly allocated to one of two groups (treatment group—TG with nisin–biogel dental application, or control group—CG without treatment) and submitted to dental plaque sampling at day 0 and after 90 days (T90). Samples were processed for Enterococcus spp. isolation, quantification, identification, molecular typing and antimicrobial and virulence characterization. From a total of 140 enterococci, molecular typing allowed us to obtain 70 representative isolates, mostly identified as E. faecalis and E. faecium. No significant differences (p > 0.05) were observed in the virulence index of the isolates obtained from samples collected from the TG and CG at T90. At T90, a statistically significant difference (p = 0.0008) was observed in the antimicrobial resistance index between the isolates from the TC and CG. Oral enterococci were revealed to be reservoirs of high resistant and virulent phenotypesinfo:eu-repo/semantics/publishedVersio

Molecular epidemiology, virulence traits and antimicrobial resistance signatures of Aeromonas spp. in the critically endangered Iberochondrostoma lusitanicum follow geographical and seasonal patterns

This research was supported by CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Project UIDB/00276/2020 (funded by FCT—Fundação para a Ciência e Tecnologia IP) and by MARE (MARE-ISPA), MARE/UIDB/MAR/04292/2020 and strategic project MARE/UIDP/MAR/04292/2020 (also funded by FCT). M.L.G. thanks funding by the University of Lisbon (PhD fellowship C10571K). T.A.M. and C.S.M. thank partial support by CEAUL (funded by FCT, Portugal, through the project UIDB/00006/2020).Despite the fact that freshwater fish populations are experiencing severe declines worldwide, our knowledge on the interaction between endangered populations and pathogenic agents remains scarce. In this study, we investigated the prevalence and structure of Aeromonas communities isolated from the critically endangered Iberochondrostoma lusitanicum, a model species for threatened Iberian leuciscids, as well as health parameters in this species. Additionally, we evaluated the virulence profiles, antimicrobial resistance signatures and genomic relationships of the Aeromonas isolates. Lesion prevalence, extension and body condition were deeply affected by location and seasonality, with poorer performances in the dry season. Aeromonas composition shifted among seasons and was also different across river streams. The pathogenic potential of the isolates significantly increased during the dry season. Additionally, isolates displaying clinically relevant antimicrobial resistance phenotypes (carbapenem and fluroquinolone resistance) were detected. As it inhabits intermittent rivers, often reduced to disconnected pools during the summer, the dry season is a critical period for I. lusitanicum, with lower general health status and a higher potential of infection by Aeromonas spp. Habitat quality seems a determining factor on the sustainable development of this fish species. Also, these individuals act as reservoirs of important antimicrobial resistant bacteria with potential implications for public health.Publisher PDFPeer reviewe

Aeromonas spp. prevalence, virulence and antimicrobial resistance in an ex situ program for threatened freshwater fish – a pilot study with protective measures

This research was supported by CIISA - Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Project UIDB/00276/2020 (funded by FCT - Fundação para a Ciência e Tecnologia IP), by MARE (MARE-ISPA), MARE/UIDB/MAR/04292/2020 and strategic project MARE/UIDP/MAR/04292/2020 (also funded by FCT) and by the Zebra Foundation for Veterinary Zoological Education, Grant “A. hydrophila in Iberochondrostoma lusitanicum”. MLG thanks funding by the University of Lisbon (PhD fellowship C10571K). TAM and CM thank partial support by CEAUL (funded by FCT, Portugal, through the project UIDB/00006/2020).Ex situ breeding programs are important conservation tools for endangered freshwater fish. However, developing husbandry techniques that decrease the likelihood of disease, antimicrobial resistance, and virulence determinants acquisition during this process is challenging. In this pilot study, we conducted a captivity experiment with Portuguese nase (Iberochondrostoma lusitanicum), a critically endangered leuciscid species, to investigate the influence of simple protective measures (i.e., material disinfection protocols and animal handling with gloves) on the dynamics of a potential pathogenic genus, Aeromonas, as well as its virulence profiles and antimicrobial resistance signatures. Our findings show that antimicrobial resistance in Aeromonas spp. collected from I. lusitanicum significantly increased during the extent of the assay (5 weeks), with all isolates collected at the end of the study classified as multidrug-resistant. Additionally, humans handling fishes without protective measures were colonized by Aeromonas spp. The use of protective measures suggested a decreasing trend in Aeromonas spp. prevalence in I. lusitanicum, while bacterial isolates displayed significantly lower virulence index values when virulence phenotypical expression was tested at 22 °C. Despite this study representing an initial trial, which needs support from further research, protective measures tested are considered a simple tool to be applied in ex situ breeding programs for aquatic animals worldwide. Furthermore, current results raise concern regarding antimicrobial resistance amplification and zoonotic transmission of Aeromonas spp. in aquatic ex situ programs.Publisher PDFPeer reviewe

New Insights on Streptococcus dysgalactiae subsp. dysgalactiae Isolates

Funding Information: This work was supported by the Unidade de Ciências Biomoleculares Aplicadas-UCIBIO, which is financed by Funding Information: Funding. This work was supported by the Unidade de Ci?ncias Biomoleculares Aplicadas-UCIBIO, which is financed by national funds from FCT/MEC (UIDP/04378/2020 and UIDB/04378/2020) and also by projects PTDC/CVT-EPI/4651/2012 and PTDC/CVT-EPI/6685/2014. FCT-MEC is also acknowledged for grant SFRH/BD/118350/2016 to CA-B. Publisher Copyright: © Copyright © 2021 Alves-Barroco, Caço, Roma-Rodrigues, Fernandes, Bexiga, Oliveira, Chambel, Tenreiro, Mato and Santos-Sanches.Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) has been considered a strict animal pathogen. Nevertheless, the recent reports of human infections suggest a niche expansion for this subspecies, which may be a consequence of the virulence gene acquisition that increases its pathogenicity. Previous studies reported the presence of virulence genes of Streptococcus pyogenes phages among bovine SDSD (collected in 2002–2003); however, the identity of these mobile genetic elements remains to be clarified. Thus, this study aimed to characterize the SDSD isolates collected in 2011–2013 and compare them with SDSD isolates collected in 2002–2003 and pyogenic streptococcus genomes available at the National Center for Biotechnology Information (NCBI) database, including human SDSD and S. dysgalactiae subsp. equisimilis (SDSE) strains to track temporal shifts on bovine SDSD genotypes. The very close genetic relationships between humans SDSD and SDSE were evident from the analysis of housekeeping genes, while bovine SDSD isolates seem more divergent. The results showed that all bovine SDSD harbor Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas IIA system. The widespread presence of this system among bovine SDSD isolates, high conservation of repeat sequences, and the polymorphism observed in spacer can be considered indicators of the system activity. Overall, comparative analysis shows that bovine SDSD isolates carry speK, speC, speL, speM, spd1, and sdn virulence genes of S. pyogenes prophages. Our data suggest that these genes are maintained over time and seem to be exclusively a property of bovine SDSD strains. Although the bovine SDSD genomes characterized in the present study were not sequenced, the data set, including the high homology of superantigens (SAgs) genes between bovine SDSD and S. pyogenes strains, may indicate that events of horizontal genetic transfer occurred before habitat separation. All bovine SDSD isolates were negative for genes of operon encoding streptolysin S, except for sagA gene, while the presence of this operon was detected in all SDSE and human SDSD strains. The data set of this study suggests that the separation between the subspecies “dysgalactiae” and “equisimilis” should be reconsidered. However, a study including the most comprehensive collection of strains from different environments would be required for definitive conclusions regarding the two taxa.publishersversionpublishe

The importance of “one health approach” to the AMR study and surveillance in Angola and other African countries

The dissemination of multidrug-resistant (MDR) bacterial isolates in low- and middle-income countries, including several African countries, is a major concern. The poor sanitary conditions of rural and urban families observed in certain regions may favor the transmission of bacterial infections between animals and humans, including those promoted by strains resistant to practically all available antibiotics. In Angola, in particular, the presence of these strains in human hospitals has already been described. Nevertheless, the information on antimicrobial resistance (AMR) prevalence in Angola is still scarce, especially regarding veterinary isolates.This review aimed to synthesize data on antimicrobial resistance in African countries, with a special focus on Angola, from a One Health perspective. The main goals were to identify research gaps that may require further analysis, and to draw attention to the importance of the conscious use of antimicrobials and the establishment of preventive strategies, aiming to guarantee the safeguarding of public health. To understand these issues, the available literature on AMR in Africa was reviewed. We searched PubMed for articles pertinent to AMR in relevant pathogens in Angola and other African countries. In this review, we focused on AMR rates and surveillance capacity.The principal findings were that, in Africa, especially in sub-Saharan countries, AMR incidence is high due to the lack of legislation on antibiotics, to the close interaction of humans with animals and the environment, and to poverty. The information about current resistance patterns of common pathogenic bacteria is sparse, and the number of quality studies is limited in Angola and in some other Sub-Saharan African countries. Also, studies on the “One Health Approach” focusing on the environment, animals, and humans, are scarce in Africa. The surveillance capacity is minimal, and only a low number of AMR surveillance programs and national health programs are implemented. Most international and cooperative surveillance programs, when implemented, are not properly followed, concluded, nor reported. In Angola, the national health plan does not include AMR control, and there is a consistent omission of data submitted to international surveillance programs. By identifying One Health strengths of each country, AMR can be controlled with a multisectoral approach and governmental commitment