We investigated the effects of pathogens associated with subclinical intramammary infections on y... more We investigated the effects of pathogens associated with subclinical intramammary infections on yield, composition and quality indicators of goat milk. By means of a longitudinal study, individual half udder milk samples (n = 132) were collected at different lactation periods and assessed for milk yield and physicochemical composition, somatic cell count (SCC), total bacteria count (TBC) and microbiological culture. Staphylococci species accounted for the great majority of the isolates (96.1%). Intramammary infections significantly reduced fat and total solids in goat milk and increased both SCC and TBC. However, these indicators were significantly higher in udder halves affected by S. aureus compared with other staphylococci species.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Abstract The objective of this study was to identify on-farm risk factors associated with microbi... more Abstract The objective of this study was to identify on-farm risk factors associated with microbiological traits and somatic cell counts of goat bulk milk. A cross-sectional study was carried out on 160 goat dairy herds. Bulk tank milk samples were collected aseptically for qualitative (Salmonella enterica) and quantitative (aerobic mesophilic bacteria, total coliforms, E. coli, Staphylococcus spp. and Staphylococcus aureus) microbiological analyses. Additionally, information on various herd characteristics, general management practices, and milking procedures was collected by means of a questionnaire. A model for risk factors associated with the investigated traits was built by means of logistic regression after selection of putative variables by univariable analysis. Absence of pre-dipping, non-discharge of foremilk before milking and confirmed mastitis cases in the herds were identified as major risk factors for high aerobic plate counts. Low milk yield ( 7 years), the use of ponds as water source, long lactation periods (> 210 days), practice of milking in late pregnancy and non-discharge of foremilk before milking were also identified as risk factors for high SCC. The information generated by this study can support intervention measures targeting the improvement of goat milk quality, which is of paramount importance for the continuous development of the goat dairy industry.
Aim: Genomic analysis of a methicillin-resistant Staphylococcus aureus (MRSA) strain cultured fro... more Aim: Genomic analysis of a methicillin-resistant Staphylococcus aureus (MRSA) strain cultured from a non-migratory seabird at Fernando de Noronha Archipelago (Brazilian oceanic islands) was carried out to investigate the potential origin of MRSA genetic determinants in an ecological setting with minimal or absent antimicrobial selective pressure, and minimal interaction with humans and domestic animals. Results: The study determined mecA gene homology and the phylogenetic relatedness with mecA described in Staphylococcus sciuri, which was the major Staphylococcus spp. cultured from the birds. Our findings corroborate in silico assumptions that the mecA gene in MRSA strains clinically relevant for humans and animals originates from S. sciuri ancestors. Conclusion: Coagulase-negative staphylococci seem to be natural reservoirs of methicillin-resistant genes to S. aureus, even in environments with very low antimicrobial selection pressure.
Abstract Small-scale dairy production plays a relevant socioeconomic role contributing to improve... more Abstract Small-scale dairy production plays a relevant socioeconomic role contributing to improve food security in low income rural settings, such as semiarid Brazil. Milk is mainly supplied to local communities, either distributed by government programs to schools and day-care units, or commercialized privately to final consumers or cheesemakers. However, there is a lack of information about the potential public health hazards associated with milk. The aim of this study was to investigate antimicrobial resistance phenotypes, the presence of enterotoxin-encoding genes and genotypic relatedness of Staphylococcus spp. from raw milk samples in the semi-arid Paraiba. High antimicrobial resistant rates were observed for beta-lactams, including penicillin, ampicillin and ceftazidime. Although 14% of the isolates were phenotypically resistant to oxacillin, mecA gene was not detected among S. aureus. Almost 50% of the isolates harbored at least one enterotoxin-encoding gene. Higher genotypic relatedness was observed among staphylococci from closely-related farms, suggesting geographic spread of certain strains. In order to prevent potential microbiological risks related to milk consumption in the region, continuous efforts towards the improvement of raw milk quality are encouraged, including good production practices, such as those related to milk refrigeration on the farms and efficient pasteurization.
This study assessed the effect of in ovo threonine supplementation on the response of broiler chi... more This study assessed the effect of in ovo threonine supplementation on the response of broiler chicks challenged with Salmonella Enteritidis, considering bacterial counts in cecal contents, intestinal morphology, body weight, and weight gain. Fertilized eggs were inoculated in the amniotic fluid with saline (NT) or 3.5% threonine (T) solution at day 17.5 of incubation. At hatch, chicks were individually weighed and cloacal swabs were screened for Salmonella. At 2 days of age, half of the birds from each in ovo treatment were given either 0.5 mL of nutrient broth (sham-inoculated) or nalidixic acid-resistant Salmonella Enteritidis (SE NalR) in nutrient broth (8.3 × 107 colony forming units (CFU) SE NalR/mL). The birds were distributed using a completely randomized design with four treatments after the Salmonella challenge: no in ovo Thr supplementation and sham-inoculated in the posthatch challenge (NT-SHAM), in ovo Thr supplementation and sham-inoculated (T-SHAM), no in ovo Thr suppl...
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2017
Staphylococcus aureus is considered a major pathogen in veterinary and human medicine, and the em... more Staphylococcus aureus is considered a major pathogen in veterinary and human medicine, and the emergence of multidrug-resistant strains, such as livestock-associated methicillin-resistant S. aureus, means that reliable, inexpensive, and fast methods are required to identify S. aureus obtained from animal sources. We tested the accuracy of a PCR targeting the genes femA, nuc, and coa in identifying S. aureus from animals. A total of 157 Staphylococcus spp. isolates were examined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry; 18 different Staphylococcus species were identified. Of 68 S. aureus isolates, the genes femA, nuc, and coa were found in 61, 53, and 32 isolates, respectively. Considering MALDI-TOF as the gold standard, the PCR assays targeting all 3 genes showed 100% specificity; the sensitivity values were 89.7, 77.9, and 47.0% for femA, nuc, and coa, respectively. Sensitivity was 100% when femA and nuc markers were targeted simul...
This investigation reported for the first time the occurrence of intramammary infections caused b... more This investigation reported for the first time the occurrence of intramammary infections caused by Staphylococcus in primiparous replacement goats before parturition and the persistence of clinical Staphylococcus aureus infection during the lactation period. Subclinical infections, mainly caused by coagulase negative staphylococci (CoNS), did not persist during lactation. Genotyping analysis indicated that environment seems to play a moderate role as source of intramammary infections to goats before parturition, but causative agents of mastitis in lactating animals are not genotypically related to environmental staphylococci. The occurrence and persistence of intramammary infections in replacement goats demonstrate the need to consider those animals as potential sources of infections in dairy goat herds.
Objetivou-se por meio deste estudo a caracterizacao da microbiota do leite caprino atraves do seq... more Objetivou-se por meio deste estudo a caracterizacao da microbiota do leite caprino atraves do sequenciamento do gene 16S rRNA associada a diferentes periodos de lactacao e quando as cabras sao criadas em diferentes regioes geograficas. No primeiro capitulo, apresentamos um referncial teorico que abrange um breve historico sobre o estudo das comunidades microbianas e os metodos utilizados para tal e finalizando com uma apresentacao de estudos metagenomicos com leite caprino e de outras especies baseados no sequenciamento de DNA. No segundo capitulo, objetivou-se determinar a comunidade microbiana do leite caprino ao longo da lactacao em animais livres de infeccao intramamaria. Foram coletadas amostras de leite de cabras mesticas e multiparas em uma propriedade localizada no semiarido paraibano em tres periodos de lactacao: inicial (50 dias), intermediario (100 dias) e final (150 dias). Nocardioides foi o genero bacteriano mais abundante independente do periodo de lactacao. Pseudomona...
We investigated the effects of pathogens associated with subclinical intramammary infections on y... more We investigated the effects of pathogens associated with subclinical intramammary infections on yield, composition and quality indicators of goat milk. By means of a longitudinal study, individual half udder milk samples (n = 132) were collected at different lactation periods and assessed for milk yield and physicochemical composition, somatic cell count (SCC), total bacteria count (TBC) and microbiological culture. Staphylococci species accounted for the great majority of the isolates (96.1%). Intramammary infections significantly reduced fat and total solids in goat milk and increased both SCC and TBC. However, these indicators were significantly higher in udder halves affected by S. aureus compared with other staphylococci species.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Abstract The objective of this study was to identify on-farm risk factors associated with microbi... more Abstract The objective of this study was to identify on-farm risk factors associated with microbiological traits and somatic cell counts of goat bulk milk. A cross-sectional study was carried out on 160 goat dairy herds. Bulk tank milk samples were collected aseptically for qualitative (Salmonella enterica) and quantitative (aerobic mesophilic bacteria, total coliforms, E. coli, Staphylococcus spp. and Staphylococcus aureus) microbiological analyses. Additionally, information on various herd characteristics, general management practices, and milking procedures was collected by means of a questionnaire. A model for risk factors associated with the investigated traits was built by means of logistic regression after selection of putative variables by univariable analysis. Absence of pre-dipping, non-discharge of foremilk before milking and confirmed mastitis cases in the herds were identified as major risk factors for high aerobic plate counts. Low milk yield ( 7 years), the use of ponds as water source, long lactation periods (> 210 days), practice of milking in late pregnancy and non-discharge of foremilk before milking were also identified as risk factors for high SCC. The information generated by this study can support intervention measures targeting the improvement of goat milk quality, which is of paramount importance for the continuous development of the goat dairy industry.
Aim: Genomic analysis of a methicillin-resistant Staphylococcus aureus (MRSA) strain cultured fro... more Aim: Genomic analysis of a methicillin-resistant Staphylococcus aureus (MRSA) strain cultured from a non-migratory seabird at Fernando de Noronha Archipelago (Brazilian oceanic islands) was carried out to investigate the potential origin of MRSA genetic determinants in an ecological setting with minimal or absent antimicrobial selective pressure, and minimal interaction with humans and domestic animals. Results: The study determined mecA gene homology and the phylogenetic relatedness with mecA described in Staphylococcus sciuri, which was the major Staphylococcus spp. cultured from the birds. Our findings corroborate in silico assumptions that the mecA gene in MRSA strains clinically relevant for humans and animals originates from S. sciuri ancestors. Conclusion: Coagulase-negative staphylococci seem to be natural reservoirs of methicillin-resistant genes to S. aureus, even in environments with very low antimicrobial selection pressure.
Abstract Small-scale dairy production plays a relevant socioeconomic role contributing to improve... more Abstract Small-scale dairy production plays a relevant socioeconomic role contributing to improve food security in low income rural settings, such as semiarid Brazil. Milk is mainly supplied to local communities, either distributed by government programs to schools and day-care units, or commercialized privately to final consumers or cheesemakers. However, there is a lack of information about the potential public health hazards associated with milk. The aim of this study was to investigate antimicrobial resistance phenotypes, the presence of enterotoxin-encoding genes and genotypic relatedness of Staphylococcus spp. from raw milk samples in the semi-arid Paraiba. High antimicrobial resistant rates were observed for beta-lactams, including penicillin, ampicillin and ceftazidime. Although 14% of the isolates were phenotypically resistant to oxacillin, mecA gene was not detected among S. aureus. Almost 50% of the isolates harbored at least one enterotoxin-encoding gene. Higher genotypic relatedness was observed among staphylococci from closely-related farms, suggesting geographic spread of certain strains. In order to prevent potential microbiological risks related to milk consumption in the region, continuous efforts towards the improvement of raw milk quality are encouraged, including good production practices, such as those related to milk refrigeration on the farms and efficient pasteurization.
This study assessed the effect of in ovo threonine supplementation on the response of broiler chi... more This study assessed the effect of in ovo threonine supplementation on the response of broiler chicks challenged with Salmonella Enteritidis, considering bacterial counts in cecal contents, intestinal morphology, body weight, and weight gain. Fertilized eggs were inoculated in the amniotic fluid with saline (NT) or 3.5% threonine (T) solution at day 17.5 of incubation. At hatch, chicks were individually weighed and cloacal swabs were screened for Salmonella. At 2 days of age, half of the birds from each in ovo treatment were given either 0.5 mL of nutrient broth (sham-inoculated) or nalidixic acid-resistant Salmonella Enteritidis (SE NalR) in nutrient broth (8.3 × 107 colony forming units (CFU) SE NalR/mL). The birds were distributed using a completely randomized design with four treatments after the Salmonella challenge: no in ovo Thr supplementation and sham-inoculated in the posthatch challenge (NT-SHAM), in ovo Thr supplementation and sham-inoculated (T-SHAM), no in ovo Thr suppl...
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2017
Staphylococcus aureus is considered a major pathogen in veterinary and human medicine, and the em... more Staphylococcus aureus is considered a major pathogen in veterinary and human medicine, and the emergence of multidrug-resistant strains, such as livestock-associated methicillin-resistant S. aureus, means that reliable, inexpensive, and fast methods are required to identify S. aureus obtained from animal sources. We tested the accuracy of a PCR targeting the genes femA, nuc, and coa in identifying S. aureus from animals. A total of 157 Staphylococcus spp. isolates were examined by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry; 18 different Staphylococcus species were identified. Of 68 S. aureus isolates, the genes femA, nuc, and coa were found in 61, 53, and 32 isolates, respectively. Considering MALDI-TOF as the gold standard, the PCR assays targeting all 3 genes showed 100% specificity; the sensitivity values were 89.7, 77.9, and 47.0% for femA, nuc, and coa, respectively. Sensitivity was 100% when femA and nuc markers were targeted simul...
This investigation reported for the first time the occurrence of intramammary infections caused b... more This investigation reported for the first time the occurrence of intramammary infections caused by Staphylococcus in primiparous replacement goats before parturition and the persistence of clinical Staphylococcus aureus infection during the lactation period. Subclinical infections, mainly caused by coagulase negative staphylococci (CoNS), did not persist during lactation. Genotyping analysis indicated that environment seems to play a moderate role as source of intramammary infections to goats before parturition, but causative agents of mastitis in lactating animals are not genotypically related to environmental staphylococci. The occurrence and persistence of intramammary infections in replacement goats demonstrate the need to consider those animals as potential sources of infections in dairy goat herds.
Objetivou-se por meio deste estudo a caracterizacao da microbiota do leite caprino atraves do seq... more Objetivou-se por meio deste estudo a caracterizacao da microbiota do leite caprino atraves do sequenciamento do gene 16S rRNA associada a diferentes periodos de lactacao e quando as cabras sao criadas em diferentes regioes geograficas. No primeiro capitulo, apresentamos um referncial teorico que abrange um breve historico sobre o estudo das comunidades microbianas e os metodos utilizados para tal e finalizando com uma apresentacao de estudos metagenomicos com leite caprino e de outras especies baseados no sequenciamento de DNA. No segundo capitulo, objetivou-se determinar a comunidade microbiana do leite caprino ao longo da lactacao em animais livres de infeccao intramamaria. Foram coletadas amostras de leite de cabras mesticas e multiparas em uma propriedade localizada no semiarido paraibano em tres periodos de lactacao: inicial (50 dias), intermediario (100 dias) e final (150 dias). Nocardioides foi o genero bacteriano mais abundante independente do periodo de lactacao. Pseudomona...
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