Genotypic insights to Panton-Valentine leukocidin positive methicillin-resistant Staphylococcus aureus isolated from cattle mastitis.

In this research communication we investigate the prevalence and antimicrobial susceptibility of S. aureus harboring virulent genes responsible for mastitis in cattle of Punjab, Pakistan. A total of 690 milk samples were collected from commercial dairy farms for analysis of the prevalence of subclinical and clinical mastitis and isolation of S. aureus. Virulence ability and methicillin resistance in S. aureus (MRSA) was determined by targeting the pvl (the gene for Panton-Valentine leukocidin) and mecA genes, respectively. A total of 175 S. aureus isolates exhibiting prevalence of pvl gene (6.28%) and mecA gene (22.28%) were determined. Antimicrobial susceptibility testing of pvl positive and negative MRSA against different classes of antibiotics revealed 100% resistance against ß-lactams while 100% sensitivity towards tylosin and linezolid.

THEILERIA EQUI INFECTION IN WORKING HORSES OF PAKISTAN: EPIDEMIOLOGY, MOLECULAR CHARACTERIZATION, AND HEMATOBIOCHEMICAL ANALYSIS.

Theileria equi is 1 of the emerging and prevailing tick-borne hemoprotozoans adversely affecting the equids worldwide, including Pakistan. The current study aimed to investigate the prevalence and molecular characterization of T. equi in working horses (n = 194), the comparative efficacy of different diagnostic tests, associated risk factors, and hematobiochemical analysis. The blood samples of horses were subjected to microscopic examination, cELISA, and polymerase chain reaction (PCR) and the results revealed a prevalence of 9.79, 21.13, and 13.40%, respectively, for T. equi in working horses. The comparison of microscopy and cELISA results with PCR showed that cELISA had higher sensitivity (84.62%), but lower specificity (88.69%) and accuracy (88.14%) in comparison to microscopy (57.69, 97.62, and 92.27%). Molecular characterization of T. equi by phylogenetic analysis revealed a 61% resemblance of study isolates with each other OL662926, OL662925, and 82% similarity with isolate OL662924 while also showing homology with T. equi isolates of South Africa, South Korea, India, Pakistan, and Brazil. The risk factor analysis revealed a significant association (P < 0.05) of tick control status, previous tick history, tick infestation, house hygiene, deworming/vaccination, and the presence of other livestock species with T. equi infection in horses. The hematobiochemical profile revealed a significant (P < 0.05) decrease in red blood cells (RBCs), hemoglobin (Hb), packed cell volume (PCV), white blood cells (WBCs), platelet (PLT), phosphorus, and an increase in lymphocytes, granulocytes, aspartate aminotransferase (AST), glucose, bilirubin, blood urea nitrogen (BUN), and creatinine in T. equi-infected horses. The current study is the first comprehensive report for comparative evaluation of microscopy, cELISA, and PCR, assessment of epidemiological risk factors as well as hematobiochemical variations due to T. equi infection in Pakistan.

Molecular evidence of ß-lactam resistant Staphylococcus aureus in equids with respiratory tract infections: Frequency and resistance modulation strategy.

The emergence of antimicrobial-resistant strains in Staphylococcus aureus (ß-lactam and methicillin-resistant) is an overwhelming issue worldwide. Using the purposive sampling technique, 217 equids samples were collected from district Layyah which were subjected to culturing followed by genotypic identification of mecA and blaZ genes by PCR. This study revealed that by phenotypic methods, a prevalence of 44.24%, 56.25%, and 47.92% was found for S. aureus, MRSA, and ß-lactam resistant S. aureus in equids. While genotypically, MRSA was found in 29.63% and ß-lactam resistant S. aureus in 28.26% of equids. In-vitro antibiotic susceptibility testing against S. aureus isolates harboring both mecA and blaZ genes showed a high resistance against Gentamicin (75%), followed by Amoxicillin (66.67%) and Trimethoprim+sulfamethoxazole (58.34%). In an attempt to re-sensitize the resistant bacteria to antibiotics, a combination of antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) was used which revealed synergistic effect of Gentamicin and Trimethoprim+sulfamethoxazole with Phenylbutazone; and Amoxicillin with Flunixin meglumine. Analysis of risk factors revealed significant association with the S. aureus-associated respiratory infection in equids. Phylogenetic analysis of mecA and blaZ genes showed a high resemblance of study isolate's sequences with each other and variable resemblance with already reported isolates obtained from different samples of neighboring countries. This study reports the first molecular characterization and phylogenetic analysis of ß-lactam and methicillin resistant S. aureus in equids in Pakistan. Moreover, this study will help in the resistance modulation of resistant antibiotics (Gentamicin, Amoxicillin, Trimethoprim+sulfamethoxazole) and provide a good insight into planning an effective therapeutic regime.