Detection and sequence analysis of accessory gene regulator genes of Staphylococcus pseudintermedius isolates

In vitro comparison between antimicrobial and antibiofilm effects of Green Propolis and Baccharis dracunculifolia against Staphylococcus pseudintermedius isolate

Staphylococcus pseudintermedius is the leading cause of canine pyoderma. Honeybee products are common to treat this and other types of infections. High average annual population loss of bees has been observed. This study evaluated antibacterial and antibiofilm profile of Green Propolis and Baccharis dracunculifolia against S. pseudintermedius and the chemical similarities among both. Ethanolic extracts were produced and chemically characterized. The isolates were subjected to treatment with the extracts in both planktonic and sessile forms. Green propolis minimum inhibitory concentration (MIC) was 0.156 mg / mL, and minimum bactericidal concentration (MBC) was 0.312mg / mL. Baccharis dracunculifolia extract MIC and MBC was 0.312mg / mL and 2.5 mg / mL, respectivelly. Both extracts reduced SD55 formation of biofilm at minimum inhibitory concentration and at 1/8 minimum inhibitory concentration. The results observed in relation to ED99, were similar for both extracts. Besides that, similar chemical indicators between both extracts, including the presence of Artepellin C, suggest that the Baccharis dracunculifolia extract could be an alternative to the Green Propolis extract in the treatment of staph infections.

Editor's Highlight: OrganophosphateDiazinon Altered Quorum Sensing, Cell Motility, Stress Response, and Carbohydrate Metabolism of Gut Microbiome

The gut microbiome plays a key role in energy production, immune system development, and host resistance against invading pathogens, etc. Disruption of gut bacterial homeostasis is associated with a number of human diseases. Several environmental chemicals have been reported to induce alterations of the gut microbiome. Diazinon, one of important organophosphate insecticides, has been widely used in agriculture. Diazinon and its metabolites are readily detected in different environmental settings and human urine. The toxicity of organophosphates has been a long-standing public health concern. We recently demonstrated that organophosphate insecticide diazinon perturbed the gut microbiome composition of mice. However, the functional impact of exposure on the gut microbiome has not been adequately assessed yet. In particular, the molecular mechanism responsible for exposure-induced microbial profile and community structure changes has not been identified. Therefore, in this study, we used metatranscriptomics to examine the effects of diazinon exposure on the gut metatranscriptome in C57BL/6 mice. Herein, we demonstrated for the first time that organophosphate diazinon modulated quorum sensing, which may serve as a key mechanism to regulate bacterial population, composition, and more importantly, their functional genes. In addition, we also found that diazinon exposure activated diverse stress response pathways and profoundly impaired energy metabolism of gut bacteria. These findings provide new understandings of the functional interplay between the gut microbiome and environmental chemicals, such as organophosphates.

Methicillin-resistant Staphylococcus pseudintermedius among dogs in the description of novel SCCmec variants

The presence and genetic characteristics of methicillin-resistant Staphylococcus pseudintermedius (MRSP) in Sri Lanka was investigated to add additional insight into global spread, emergence and evolution of MRSP. A total of 234 samples from dogs visiting veterinary clinics were cultured for staphylococci and the genomes of the MRSP isolates were sequenced, to identify resistance genes, the multilocus sequence types (MLST) and spa types. From a questionnaire the history of antimicrobial treatment and patient information was obtained. S. pseudintermedius was isolated from 116/229 samples, eight of these were MRSP. Six MRSP CC45 isolates contained a pseudo-SCC element ΨSCCmec₅₇₃₉₅. Two isolates belonging to ST429 (CC761) and ST121 (CC121) contained novel variants of the SCCmec Type V(T) element. The elements were designated SCCmecV(T)_SL/066, that carried additional transposon-related genes, and SCCmecV(T)_SL/154 that carried a type III restriction-modification system, a type 7 ccr gene complex, and a cadA coding sequence. Thirty-seven percent of the dogs received antimicrobial treatment at the time of sampling of which four dogs were MRSP-positive. The proportion of MRSP among S. pseudintermedius is low compared to other countries, despite the fact that in Sri Lanka antimicrobials for treatment of dogs are available over the counter. Important is the finding of novel type V(T) SCCmec elements, which further underlines the high recombination frequency of SCC elements. The ΨSCCmec₅₇₃₉₅ was found in isolates of CC45, which is the only sequence type of MRSP known to contain this pseudo-cassette.

Dermatophilus congolensis infection in sheep and goats in Delta region of Tamil Nadu

Aim

The study was conducted to isolate and identify Dermatophilus congolensis (DC) using conventional and molecular diagnostic techniques in scab materials collected from skin infections of sheep and goats in the Delta region of Tamil Nadu.

Materials and Methods

A total of 20 scab samples collected from 18 goats and 2 sheep from Nagapattinam, Thanjavur, and Tiruvarur districts of Tamil Nadu. Smears were made from softened scab materials and stained by either Gram's or Giemsa staining. Isolation was attempted on blood agar plates, and colonies were stained by Gram's staining for morphological identification. Identification was also done by biochemical tests and confirmed by 16S rRNA polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis of the amplified product.

Results

The peculiar laddering arrangement of coccoid forms in stained smears prepared from scab materials revealed the presence of DC. Isolated colonies from scab materials of sheep and goats on bovine blood agar plate were small, hemolytic, rough, adherent, and bright orange-yellow in color, but some colonies were white to cream color. Gram-staining of cultured organisms revealed Gram-positive branching filaments with various disintegration stages of organisms. 16S rRNA PCR yielded 500 bp amplicon specific for DC. Sequence analysis of a sheep DC isolate showed 99-100% sequence homology with other DC isolates available in NCBI database, and phylogenetic tree showed a close cluster with DC isolates of Congo, Nigeria, and Angola of Africa. Genes for virulence factors such as serine protease and alkaline ceramidase could not be detected by PCR in any of the DC strains isolated of this study.

Conclusion

The presence of dermatophilosis in Tamil Nadu was established from this study.