-
Foodborne Pathogens and Disease Oct 2019Bulk tank milk from 58 dairy goat and sheep flocks located in southern Spain was examined to determine the prevalence and distribution of . A total of 45 isolates were...
Bulk tank milk from 58 dairy goat and sheep flocks located in southern Spain was examined to determine the prevalence and distribution of . A total of 45 isolates were obtained and characterized to determine the species, antimicrobial resistance profile, and genetic similitude by pulse-field gel electrophoresis (PFGE) using I. isolates were confirmed by polymerase chain reaction (PCR) analysis of , and resistance to methicillin was determined by PCR analysis of A. A total of 10 different staphylococcal species were identified, 22.2% and 77.8% of which were coagulase positive and negative, respectively. Twenty-two (48.89%) isolates were resistant to at least one antimicrobial agent. Higher antimicrobial resistance values were obtained against tetracycline (28.9%) and penicillin (22.2%). Two isolates ( and ) were resistant to cefoxitin; however, none of the 45 isolates harbored A. Thirty pulsotypes were detected by PFGE. Interestingly, some isolates of , , , and showed high genetic similarity (>80%). These data suggest that genetically similar staphylococcal isolates circulate among goat and sheep dairy herds, and their different resistance patterns could be influenced by the management systems used.
Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Bacterial; Female; Goats; Microbial Sensitivity Tests; Milk; Polymerase Chain Reaction; Prevalence; Sheep; Spain; Staphylococcal Infections; Staphylococcus; Staphylococcus aureus
PubMed: 31157980
DOI: 10.1089/fpd.2018.2593 -
Frontiers in Microbiology 2019Biogenic amines (BAs) in sausages represent a health risk for consumers, and thus investigating the BAs accumulation mechanism is important to control the BAs. In this...
Biogenic amines (BAs) in sausages represent a health risk for consumers, and thus investigating the BAs accumulation mechanism is important to control the BAs. In this study, the BAs profiles of 16 typical Chinese sausage samples were evaluated, and 8 kinds of common BAs were detected from different samples. As a whole, the BAs contents of the majority of Chinese sausage samples were within the safe dosage range, except that the total BAs and histamine concentrations of sample HBBD were above the toxic dosage levels. Furthermore, the bacterial and fungal communities of the Chinese sausage samples were investigated by high-throughput sequencing analysis, and , , , , , and were identified as the predominant genera. Accordingly, 13 representative strains were selected from the dominant genera, and their BAs formation and degradation properties were evaluated. Finally, the results of fermented meats model experiment indicated that the isolates including Sp, Se, Sc1, Sc2, and Ss could significantly reduce BAs, possessing the potential as the starter cultures to control the BAs in fermented meat products. The present study not only helped to explain the BAs accumulation mechanism in Chinese sausage, but also developed the candidates for potential BAs control in fermented meat products.
PubMed: 31130922
DOI: 10.3389/fmicb.2019.00872 -
Veterinary World Jun 2017This study was devoted to elucidate the tetracycline resistance of coagulase-negative staphylococci (CNS) derived from normal and subclinical mastitic (SCM) buffaloes'...
AIM
This study was devoted to elucidate the tetracycline resistance of coagulase-negative staphylococci (CNS) derived from normal and subclinical mastitic (SCM) buffaloes' milk in Egypt.
MATERIALS AND METHODS
A total of 81 milk samples from 46 normal buffalo milk samples and 35 SCM buffalo milk samples at private dairy farms of Egypt were used in this study. CNS were identified using phenotypic and molecular methods (polymerase chain reaction [PCR]). CNS isolates were tested for tetracycline resistance using routine methods and multiplex PCR targeting tetracycline () resistance genes followed by sequencing of positive PCR products and phylogenetic analysis.
RESULTS
Isolation and identification of 28 (34.5%) CNS from normal and SCM buffaloes' milk, namely, (39.2%), (25.0%), (10.7%), (10.7%), and 3.5% to each of , , , and . Using nested PCR, all the 28 CNS isolates revealed positive for 16srRNA gene specific for genus staphylococci and negative for thermonuclease () gene specific for species. The presence of tetracycline resistance-encoding genes (K, L, M, and O) was detected by multiplex PCR. All isolates were negative for L, M, and O genes while 14 (50%) CNS isolates were positive for K gene, namely, (100%), (100%), (66.6%), (45.4%), and (42.8%). Nucleotide sequencing of K gene followed by phylogenetic analysis showed the high homology between our CNS isolates genes of tetracycline resistance with isolates including Egyptian ones. This proves the transfer of the tetracycline resistance encoding genes between coagulase-negative and coagulase positive spp.
CONCLUSION
CNS isolates have distinguishingly high resistance to tetracycline. Abundant tetracycline usage for mastitis treatment leads to the spread of genetic resistance mechanisms inside CNS strains and among all spp. Consequently, tetracycline is not effective anymore.
PubMed: 28717325
DOI: 10.14202/vetworld.2017.702-710 -
Journal of Microbiology and... Jun 2023Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic...
Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic strategies. We evaluated the effects of a nutraceutical enzyme and botanical blend (NEBB) on established biofilm. Five microbial strains with known implications in chronic human illnesses were tested: , and . The strains were allowed to form biofilm in vitro. Biofilm cultures were treated with NEBB containing enzymes targeted at lipids, proteins, and sugars, also containing the mucolytic compound N-acetyl cysteine, along with antimicrobial extracts from cranberry, berberine, rosemary, and peppermint. The post-treatment biofilm mass was evaluated by crystal-violet staining, and metabolic activity was measured using the MTT assay. Average biofilm mass and metabolic activity for NEBB-treated biofilms were compared to the average of untreated control cultures. Treatment of established biofilm with NEBB resulted in biofilm-disruption, involving significant reductions in biofilm mass and metabolic activity for and both species. For , we observed reduced biofilm mass, but the remaining residual biofilm showed a mild increase in metabolic activity, suggesting a shift from metabolically quiescent, treatment-resistant persister forms of to a more active form, potentially more recognizable by the host immune system. For , low doses of NEBB significantly reduced biofilm mass and metabolic activity while higher doses of NEBB increased biofilm mass and metabolic activity. The results suggest that targeted nutraceutical support may help disrupt biofilm communities, offering new facets for integrative combinational treatment strategies.
Topics: Humans; Anti-Bacterial Agents; Staphylococcus aureus; Anti-Infective Agents; Staphylococcal Infections; Biofilms; Pseudomonas aeruginosa; Microbial Sensitivity Tests
PubMed: 37072676
DOI: 10.4014/jmb.2212.12010 -
Drug Metabolism and Personalized Therapy Dec 2023Antibiotic resistance is rising, prompting innovative strategies for eradicating the epidemic. This study investigated the antibacterial properties of the leaves of a...
OBJECTIVES
Antibiotic resistance is rising, prompting innovative strategies for eradicating the epidemic. This study investigated the antibacterial properties of the leaves of a widely used medicinal plant, .
METHODS
The plant's polar (water, methanol) and non-polar (hexane) extracts were tested against several different bacterial strains using the disc diffusion technique.
RESULTS
In a study, it was found that the water extract had the greatest inhibitory effect on and , with minimum inhibitory concentrations of 16.444 and 19.315 g/mL, respectively. Gram-negative strains were more susceptible to plant extracts than Gram-positive strains. The phytochemical analysis indicated the presence of secondary metabolites such as alkaloids, saponins, flavonoids, tannins, and steroids, where absorbance was recorded at 415 nm. The water extract had the highest amount of phenolics, with a total phenolic content of 53.92 0.47 mg and a total flavonoid content of 7.25 0.08 mg. Results suggest that the extract may have potential therapeutic applications for antimicrobial properties.
CONCLUSIONS
The study concluded that the extract's phenolic group of secondary metabolites were responsible for its antibacterial activity. The study highlights as a promising source for discovering new and effective antibacterial compounds.
Topics: Humans; Plants, Medicinal; Plant Extracts; Justicia; Anti-Infective Agents; Anti-Bacterial Agents; Flavonoids; Water; Phenols; Plant Leaves
PubMed: 37381682
DOI: 10.1515/dmpt-2023-0012 -
Journal of Dairy Science Dec 2019Coagulase-negative staphylococci (CNS) are one of the most common bovine mastitis pathogens found worldwide. In this study, we investigated the prevalence and...
Coagulase-negative staphylococci (CNS) are one of the most common bovine mastitis pathogens found worldwide. In this study, we investigated the prevalence and distribution of CNS species in mastitis milk samples and further characterized the methicillin-resistant (MR) CNS. A total of 311 CNS were isolated from 3,692 quarter milk samples from 1,373 dairy cattle at 81 farms between 2013 and 2017. Further evaluation of the CNS isolates revealed 14 CNS species among the samples and 3 predominant species-namely, Staphylococcus chromogenes, Staphylococcus simulans, and Staphylococcus epidermidis. Resistance was higher in S. epidermidis than in other CNS species except for resistance against oxacillin in Staphylococcus sciuri. Resistance to β-lactams was the most common in all CNS species (8.4% in ampicillin, 21.2% in oxacillin, and 13.5% in penicillin). Conversely, only minimal resistance to cephalothin, ceftiofur, and pirlimycin/novobiocin was found. Twenty-one isolates from 4 species were mecA-carrying MRCNS strains, including 18 S. epidermidis and 1 each of S. sciuri, Staphylococcus equorum, and Staphylococcus hominis. The majority of the mecA-carrying MRCNS isolates were produced in the biofilm. Furthermore, multidrug-resistant sequence type 179 isolate produced the strongest biofilm. Seven genotypes were detected in the 18 MR S. epidermidis strains, the most predominant of which persisted on a farm for 2 yr. Our findings for the antimicrobial susceptibility profiles and genotypic characterization of the MRCNS isolates could provide valuable information for controlling the spread of resistance and the selection of appropriate antimicrobial therapies for mastitis in the future. Further, strategic antibiotic use for mastitis treatment and hygienic management practices aimed at the prevention of the growth of resistant bacteria are urgently needed on dairy farms.
Topics: Animals; Anti-Bacterial Agents; Cattle; Coagulase; Drug Resistance, Bacterial; Farms; Female; Genotype; Mastitis, Bovine; Milk; Oxacillin; Prevalence; Republic of Korea; Staphylococcal Infections; Staphylococcus; Staphylococcus epidermidis
PubMed: 31548061
DOI: 10.3168/jds.2019-17028 -
JAC-antimicrobial Resistance Apr 2024CoNS constitute a significant part of the human microbiota of skin and mucous membranes. They can cause nosocomial infections, and have shown decreased susceptibility to...
BACKGROUND
CoNS constitute a significant part of the human microbiota of skin and mucous membranes. They can cause nosocomial infections, and have shown decreased susceptibility to several antibiotics. The few remaining treatment options include (lipo)glycopeptides such as dalbavancin. However, there is a lack of knowledge concerning whether susceptibility to lipoglycopeptides varies between different species of CoNS.
OBJECTIVES
To determine the susceptibility to dalbavancin in different species of CoNS.
METHODS
We investigated 480 bacterial isolates from 10 CoNS species: , , , , , , , , and . The isolates were randomly selected from different sources of infection, including blood isolates, as well as deep and superficial infections. Antibiotic susceptibility was tested with the gradient test method.
RESULTS
There was a statistically significant difference (ANOVA; < 0.0001) in the MIC distribution for dalbavancin between different CoNS species. was the least susceptible species, with 90% of the isolates having an MIC value for dalbavancin above the EUCAST breakpoint of 0.125 mg/L. The lowest MIC values were seen for , and (all 0.032 mg/L).
CONCLUSIONS
This study demonstrated a difference in dalbavancin susceptibility between different CoNS species, suggesting that species-specific breakpoints for CoNS should be further investigated.
PubMed: 38601789
DOI: 10.1093/jacamr/dlae063 -
Preparative Biochemistry & Biotechnology 2019, among other staphylococcal species, developed multidrug resistance and causes serious health risks that require complex treatments. Therefore, the development of novel...
, among other staphylococcal species, developed multidrug resistance and causes serious health risks that require complex treatments. Therefore, the development of novel and effective strategies to combat these bacteria has been gaining importance. Since lysostaphin is a peptidoglycan hydrolase effective against staphylococcal species, the enzyme has a significant potential for biotechnological applications. Despite promising results of lysostaphin as a bacteriocin capable of killing staphylococcal pathogens, it is still not widely used in healthcare settings due to its high production cost. In this study, medium engineering techniques were applied to improve the expression yield of recombinant lysostaphin in . A new effective inducible promoter system and different mediums were used to enhance lysostaphin production. Our results showed that the composition of autoinduction media enhanced the amount of lysostaphin production 5-fold with the highest level of active lysostaphin at 30 °C. The production cost of 1000 U of lysostaphin was determined as 4-fold lower than the previously proposed technologies. Therefore, the currently developed bench scale study has a great potential as a large-scale fermentation procedure to produce lysostaphin efficiently.
Topics: Arabinose; Bacterial Proteins; Culture Media; Enzyme Induction; Enzyme Stability; Escherichia coli; Fermentation; Lysostaphin; Metabolic Engineering; Promoter Regions, Genetic; Recombinant Proteins; Staphylococcus; Temperature; Time Factors
PubMed: 31017522
DOI: 10.1080/10826068.2019.1599393 -
Avian Pathology : Journal of the W.V.P.A Feb 2017This report suggests a strong association between coagulase-negative Staphylococcus simulans and endocarditis in broiler chickens of a single flock. Clinical signs...
This report suggests a strong association between coagulase-negative Staphylococcus simulans and endocarditis in broiler chickens of a single flock. Clinical signs included increased mortality and lameness, and some dead chickens were found on their backs. Lesions included cauliflower-like, fibrinous vegetative lesions on the left atrioventricular valve; cream-coloured, necrotic foci of varying size in the liver; and necrosis of the femoral head. Histopathological examination of the heart revealed multifocal conglomerates of bacterial colonies attached to the valvular endocardium, threads of fibrin, and inflammatory cells with the presence of heterophils. S. simulans strains were first identified by API ID32, and then confirmed with Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry and by partial sequencing of the rpoB and dnaJ genes. These bacteria were resistant to methicillin but sensitive to vancomycin and characterized by slime production and protease activity.
Topics: Animals; Anti-Infective Agents; Chickens; Drug Resistance, Bacterial; Endocarditis; Fibrin; Methicillin; Necrosis; Staphylococcal Infections; Staphylococcus; Vancomycin; Virulence Factors
PubMed: 27329995
DOI: 10.1080/03079457.2016.1203392 -
Journal of Dairy Science Nov 2023Subclinical mastitis can be common among freshly calved heifers (FCH), but the prevalence differs between herds, possibly due to variation in risk factors. The aims of...
Subclinical mastitis can be common among freshly calved heifers (FCH), but the prevalence differs between herds, possibly due to variation in risk factors. The aims of this observational study were to identify differences in occurrence of intramammary infection (IMI) in FCH between herds with documented good or poorer first-parity udder health based on cow somatic cell count (CSCC) in early lactation, and to study herd differences in animal factors important for udder health, such as udder and hock skin lesions and animal cleanliness. Three groups of herds were included: those with high proportions of FCH with low CSCC (≤75,000 cells/mL) at the first 2 milk recordings after calving (LL), herds with high proportions of FCH with high CSCC (>100,000 cells/mL) at the first and low CSCC at the second recording (HL), and herds with high proportions of FCH with high CSCC at both recordings (HH). Thirty-nine herds (13 LL, 11 HL, 15 HH) were visited 3 times during a 12-mo period for observation of cleanliness and hock lesions, and sampling of udder and teat skin using swab cloths of milk-fed calves, early-pregnant heifers, and late-pregnant heifers. In 25 (9 LL, 9 HL, 7 HH) udder quarter samples from colostrum and milk on d 3 to 4 after calving were taken by the farmers from FCH during one year. The farmers also provided information on calving (individual or group), use of restraint and oxytocin at milking, and presence of teat and udder skin lesions. Bacterial growth in swab samples and quarter samples was investigated by culturing, and a selection of isolates was genotyped using whole-genome sequencing. Cleanliness, hock and udder skin lesions other than udder-thigh dermatitis, and growth of bacteria in swab samples did not differ between herd groups. It was more common that FCH from LL herds, compared with FCH in HH and HL herds, calved in a group of animals. Use of restraint at milking was more common in LL herds than in HH herds, whereas presence of udder-thigh dermatitis was lowest in LL herds. Specific infection was found in 14% of 5,593 quarter samples from 722 FCH. The most common IMI was Staphylococcus chromogenes. Growth of Staphylococcus simulans was more common in HH than in LL and HL herds. In colostrum samples, Staphylococcus haemolyticus was more common in HL and HH than in LL herds. The proportion of quarters with the same specific infection at both samplings was higher in HH than in LL herds and tended to be higher in HH than in HL herds. The proportion of quarters with Staph. chromogenes IMI at both samplings tended to differ between herd groups and was highest in HH herds. Whole-genome sequencing found the same sequence type of Staph. chromogenes and Staphylococcus aureus in both samples in almost all quarters with the same infection at both samplings. The differences in IMI between herd groups were in line with the higher somatic cell count in HH herds. The reasons for the predominance of Staph. chromogenes IMI in FCH need further studies.
PubMed: 37210369
DOI: 10.3168/jds.2022-22995