The aim of the study was evaluation of the concentrations of interleukin (IL)-1β, IL-8, IL-12β and tumour necrosis factor alpha (TNF-α) in the serum and milk of cows with mastitis caused by Streptococcus agalactiae.

Objective: Present research aims to isolate, identify, and determine the virulence of the Streptococcus agalactiae (group B Streptococcus; GBS), isolated from popped eye disease affected Tilapia and Vietnamese Koi (V. Koi) fishes. Materials and Methods: A total of 330 fish samples were collected, of which Tilapia (n = 180) and V. Koi (n = 150), were collected from 35 affected ponds of four selected districts of Bangladesh. Isolation of the bacterium was done using different culture media (Nutrient broth, Plate count agar, Tryptic Soy Agar, and Blood agar), and identification by using various biochemical tests (con¬ventional and using API 20 Strep kit) and polymerase chain reaction (PCR) using primers against 16S rRNA gene of S. agalactiae. Antibiotic susceptibility of the bacteria was performed using seven different antibiotics disc (Tetracycline, Oxytetracycline, Chlortetracycline, Streptomycin, Ciprofloxacin, Gentamicin, and Neomycin). Virulence of the isolated S. agalactiae was determined by infecting healthy Tilapia and V. Koi fishes through experimental infection. Results: Isolated bacteria were found Gram-positive paired and chained cocci, β-hemolytic and non-motile. Findings of biochemical and serological tests indicate that the isolated bacterium belongs to Group B Streptococcus of Lancefield classification. PCR result also confirmed that the bacteria were S. agalactiae. The bacterial isolates possessed resistance property against all the seven antibiotics used in this study. The isolated GBS was found highly virulent and showed 80%90% mortality for Tilapia and V. Koi fishes in experimental infection within 16 days of post-infection. Conclusion: From the findings of this study, it may be concluded that isolated GBS from the Tilapia and V. Koi fishes were highly virulent and possessed multidrug-resistance properties. [J Adv Vet Anim Res 2021; 8(1.000): 14-23]

Streptococcal species isolated from dairy cows with clinical mastitis were obtained from mastitis research workers in Florida, Louisiana, New York, Vermont, Washington, and West Virginia. Seventy-one streptococcal isolates were tested, including 39 strains of Streptococcus agalactiae, 21 strains of S dysgalactiae, and 11 strains of S uberis. The minimal inhibitory concentration of erythromycin, lincomycin, oxytetracycline, penicillin, spectinomycin, streptomycin, and tetracycline was determined for each isolate. Differences were not detected among strains with respect to geographic origin. None of the strains was resistant to penicillin. Lincomycin was the next most effective antimicrobial, with only 2 resistant strains of each streptococcal species. There were no differences among the streptococcal species with respect to resistance to either penicillin or lincomycin. Streptococcus uberis was more likely to be resistant to erythromycin than were S agalactiae and S dysgalactiae (P < 0.02). Streptococcus agalactiae and S uberis had similar distributions for resistance to oxytetracycline, tetracycline, spectinomycin, and streptomycin. Strains of S dysgalactiae were more likely to have intermediate resistance to oxytetracycline and streptomycin than were strains of S agalactiae and S uberis, which were highly resistant to oxytetracycline and streptomycin (P < 0.001). Differences were not detected among the streptococcal species with respect to resistance to spectinomycin. Resistance to multiple antimicrobials was observed in all streptococcal species tested. Although S dysgalactiae appeared to have a greater percentage of strains (73%) that were resistant to multiple antimicrobials than did S agalactiae (31%) or S uberis (45%), differences were not statistically significant.

Phagocytic and oxidative metabolic activities of bovine blood neutrophils were determined in the presence of glycolytic (NaF) and cytoskeletal (colchicine, cytochalasin B, and prostaglandin E1) inhibitors. Phagocytosis and postphagocytic oxidative metabolic activity, measured by nitroblue tetrazolium reduction, were determined using zymosan, Escherichia coli, Staphylococcus aureus, or Streptococcus agalactiae. Sodium fluoride (1.25 micromolar to 1.25 mM concentrations) did not significantly (P greater than 0.05) inhibit phagocytosis of S aureus and Str agalactiae, whereas phagocytosis of zymosan and E coli was significantly (P less than 0.05) inhibited only at 1.25 mM concentration. Colchicine at 1.25 nM to 1.25 micromolar conce ntrations significantly inhibited phagocytosis of zymosan and E coli, but not of S aureus and Str agalactiae. Cytochalasin B at 1.25 nM to 1.25 micromolar concentrations significantly inhibited phagocytosis of zymosan and all 3 bacteria, whereas prostaglandin E1 was noninhibitory at similar concentrations. Nitroblue tetrazolium reduction, in general, was not significantly affected by NaF and cytoskeletal inhibitors.

Comparisons were made among rapid latex agglutination test and conventional biochemical tests used to identify Streptococcus agalactiae and Staphylococcus aureus. Ninety-eight streptococci and 149 staphylococci isolated from bulk tank milk were tested. Sensitivity and specificity for the latex agglutination test used for identification of Str agalactiae were 97.6 and 98.2%, respectively. Sensitivity and specificity for the latex agglutination test used for identification of S aureus were 90.2 and 67.5%, respectively. Of 25 staphylococci considered false-positive by the latex agglutination test, 14 (56%) were considered tube coagulase-positive. Fifteen staphylococci considered false-positive by latex agglutination test had biotypes representative of S hyicus or S xylosus.

Public health is at risk because Streptococcus agalactiae is increasingly linked to incidences of bovine mastitis in Egypt. In this study, enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) were used to explore the genotyping of several antibiotic resistant Streptococcus agalactiae isolated from bovine mastitis and retail milk. Also, antimicrobial resistance genes were detected. Two hundred and sixty-six (46.7%) strains were isolated from samples of milk obtained from cases of bovine mastitis in dairy farms and retail markets representing 34 (5.96%) Streptococcus agalactiae and 232 (40.7%) other Streptococcus species strains based bacterial identification. By using of disc diffusion assays, it was examined the susceptibility of all Streptococcus isolates to twelve antimicrobial agents. The   highest prevalence of resistance of Streptococcus species was observed against ampicillin (65.5%), amoxicillin (56%), tetracycline (52.5%), ofloxacin (47.8%), and nitrofurantoin (46.9%). High proportion of the S. agalactiae isolates were resistance to amoxicillin (83%), followed by tetracycline (82.4%), nitrofurantoin (64.7%), azithromycin (61.8%), and ampicillin (50%). Most (88.2%) of S. agalactiae showed multiple antibiotic resistances (MAR) phenotypes with MAR index of 0.1-0.7 and 28 different MAR patterns. The results of genetic antimicrobial resistance of S. agalactiae strains revealed amplification of blaTEM (23%) and blaCTX (26%) genes in β-lactam-resistant strains, erm(B) gene (20%), mef(A) (35%) in macrolides resistant isolates, and tet(M) in  (44%) tetracycline resistant strains. Using ERIC-PCR, the present study showed the genetic diversity and heterogeneity among S. agalactiae strains (n=34) that were classified into 19 distinct ERIC-PCR groups (A–S).  Between them, ERIC O (20.6%, 7) was the most widespread group. These results indicated that milk samples served as source of MAR S. agalactiae, consequently posing threats to public health, so the improvement of the hygiene regimen on the farms and promotion of the wise use of antimicrobials are necessary. The obtained findings showed that milk samples were a source of MAR S. agalactiae, endangering public health. As a result, it is essential to enhance farm hygiene practices and promote the responsible use of antimicrobials. Additional research on the epidemiology of S. agalactiae is required to add bacterial genetic information in order to help in rational vaccine strategy in the future.

To investigate the feasibility of using changes in body or mammary temperature to detect mastitis, radiotransmitters were implanted midway between rear udder quarters and in the peritoneal cavity of 5 Holstein cows (1 to 3 months in lactation) housed in an environmental chamber (16 +/- 2 C; lights on 7:00 AM to 11:00 PM). After a 6-week control period, Escherichia coli endotoxin (0.5 mg) was injected after the morning milking into left rear teat cisterns via the teat canal. Wisconsin mastitis test score and somatic cell count in all quarters increased significantly (P < 0.01) by the next milking. Effects were greatest in the endotoxin-exposed quarters. Milk yields for all quarters decreased significantly (P < 0.01) by the first milking after endotoxin injection. Udder and body temperatures at milkings were similar and were not affected by treatment. When temperatures were averaged for the 5 cows for each of 120 time points/d, average temperatures, relative to time of injection of endotoxin, were increased by 0.5 C above baseline at 2.75 hours, peaked at + 2.9 C at 6.50 hours, and remained high through 9.25 hours after injection. Power spectra calculated for individual cows on a daily basis universally indicated an increase in power at low frequencies on the day of injection. Subsequently, Streptococcus agalactiae (200 colony-forming units) was injected into right rear teat cisterns. Wisconsin mastitis test score increased at the second milking after injection. Cell count and quarter milk yield decreased by the third milking. As with endotoxin, injection of S agalactiae could not be detected via a change in temperature at milkings. Of the 5 cows, 3 had a peak in temperature after injection of S agalactiae. Average temperatures for these 3 cows relative to time of injection, were increased by 0.5 C above baseline at 24.25 hours, peaked at + 1.4 C at 26.25 hours, and remained high through 28.75 hours after injection. Power spectra calculated for the day in which a temperature peak was detected for these 3 cows indicated an increase in power at low frequencies, compared with spectra for all other days. Similar increases in power were also detected for the 2 cows that did not have temperature peaks. When clinical signs of mastitis are obvious at milking, there is little advantage of using body temperature for detection of infection. When clinical signs are not obvious, body temperature is often only minimally increased. Thus, monitoring body temperature at milkings adds little to the ability to detect mastitis. Of more interest is the ability to detect transient temperature increases that often develop in association with less-severe infections. Also, as early treatment increases the likelihood of successful treatment, detection of the onset of temperature increases would be advantageous for treatment of severe infections. Detection of a transient temperature peak requires taking temperature readings every 2 hours. To detect mastitis when a temperature peak does not occur requires measurement every 15 minutes to calculate power spectra. The ability to detect the onset of acute clinical infections and subclinical infections, using frequent temperature readings, indicates that development of a practical radiotelemetry system for use on farms may be warranted, depending on cost. The added potential of using body temperature to monitor general health and to detect estrus enhances the economic feasibility of developing such a system.