Immuno-histomorphometric studies and the effect of some antibiotic alternatives on she-camel staphylococcus mastitis

الملخص EN

Bacteriological examination of 50 she camel's udder tissue samples collected from different slaughter houses revealed that Staphylococcus spp.

were the most common isolated bacteria (90 %) as single and mixed infection followed by environmental Streptococcus spp.

(40%) then E.coli (26%) in the form of mixed infection.

Most of the isolated S.aureus and coagulase negative staphylococci (CNS) were resistant to 14 commercially available antibiotic discs.

By using 4 antimicrobial peptides (AMPs) as alternatives to antibiotics; included lysozyme (Lz), lactoferrin (Lf), serum amyloid A (SAA) and haptoglobin (Hp) the results revealed only Lz and Lf have antibacterial activities for both S.aureus and CNS isolated from the udder tissues while SAA and Hp did not show antibacterial effects for the tested strains.

By using combinations of the different antibiotics and the four AMPs we noticed significant synergistic effect for all of them on the tested strains.

Analysis of protein profile of the infected udder tissue samples with both S.aureus and CNS using SDS-PAGE used to evaluate the immunological status of the naturally infected she camel mammary tissue samples with S.aureus or CNS in comparison to bacteriologically negative mammary tissue samples and the results cleared that the concentrations of Lz, Lf, Hp and mSAA were significantly higher in tissue samples infected with both S.aureus and CNS when compared with the non-infected tissue samples.

While the concentration of Lf showed a significant rise in tissue samples infected with CNS when compared with tissue samples infected with S.

aureus.

UPGMA clustering dendrogram analysis was applied to compare the protein fingerprints of the isolated Staphylococcus spp.

and illustrated that there were no or weak similarities in the protein fingerprints of the different isolated S.aureus and CNS strains ranging from (0 – 0.36).

In the present study, histopathological changes in singly isolated S.aureus mastitic tissue sections revealed grossly, varied degrees of congestion with oedema in 19 (38 %) of the mammary tissue samples which represented 7 tissue samples of acute diffuse mastitis (14%) only 2 of them showed suppuration and 12 cases (24%) subacute interstitial mastitis and the majority of tissue samples 26 (52%) showed fibrosis and paleness.

On the other hand, microscopically exhibited severe histological changes which varied from epithelial degeneration, alveolar atrophy and necrosis, in the acute and sub-acute suppurative inflammatory response marked by neutrophil infiltration, congestion, to increased stromal tissue (fibrosis) and presence of non-suppurative inflammation marked by lymphocytic infiltration in alveoli with disappearance of the alveolar lumen, through fibrosis to the complete destruction of the parenchyma in chronic mastitis which was the most majority noticed type of mastitis was chronic non suppurative mastitis.

Histochemicallly, interstitial, perialveolar, intra and inter acinar fibrosis were confirmed with Masson’s Trichrome stain as greenish blue fibres.

The activity of alkaline phosphatase in tissue sections of non mastitic animals showed high secretory activity on the outer boundary of alveolar secretary cells.

While, tissue sections taken from S.

aureus singly infected mastitic animals showed weak alkaline phosphatase activity (AP), on the outer membrane and weak protein expression by protein loci (mercury–bromophenol blue) comparing to the non-mastitic once.

On the other hand histomorphometrically, tissue sections from singly infected S.

aureus showed (P<0.05) significant decrease in alveolar diameter, number of alveoli and alveolar cell population whereas the interstitial connective tissues showed (P<0.05) significant increase compared to the non mastitic tissue.

We concluded that, Staphylococci were the major bacteria causing mastitis in she camels and showed great differences in their protein profiles, consequently caused significant increase in the inflammatory responses of the udder tissues represented by the increase of Lz, Lf, SAA and Hp concentrations in the tissues.

Staphylococci as single infection enough for inducing sever degenerative changes and damage that reflecting impaired activity as well as printed on the different histopathological, histochemical and morphometric changes in she camel’s mammary parenchyma.

Furthermore, this study offers opportunities for development of treatment strategies that may eliminate or even reduce mammary tissue damage caused by Staphylococcal mastitis with or without the use of antibiotics and/or anti-inflammatory molecules like Lz, Lf, SAA and Hp.