Comparison of virulence factors and biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections

The aim of this study was to find different prevalence of genes involved in the biofilm formation process and to assess the phenotypic and genotypic markers of biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections. In this study, 215 S. aureus strains were collected from human and dairy cow's infections. The biofilm forming capacity of the strains was evaluated using a colorimetric microtiter plate assay. The genes encoding microbial surface components, recognizing adhesive matrix molecules (MSCRAMMs) (ebpS, eno, fib, fnbA, fnbB, cna and bap), and the intracellular adhesion (ica) genes (icaA, and icaD) were targeted by polymerase chain reaction (PCR)-based method. Approximately 70 of the isolates produced biofilm. Among these, 59.3 were producers of weakly adherent biofilms while 34.8 and 5.8 produced moderate and strong biofilms, respectively. The most prevalent gene was icaD found in 88.4 of the isolates, followed by icaA, fib and eno found in 87.9, 75.8 and 75.3 of the isolates, respectively. The bap gene was not detected in any of the isolates. The prevalence of ebpS and fnbA genes among bovine isolates were significantly higher than those in human isolates, whilst the prevalence of cm gene was significantly higher in the human isolates. In this study, a high prevalence of biofilm production was found among S. aureus strains isolated from human and bovine infections. Most biofilm producing isolates were positive for MSCRAMM, icaA, and icaD genes. (C) 2015 Elsevier Ltd. All rights reserved

Effect of lactose extender with different levels of osmolality and pH on the viability of Bactrian camel (Camelus bactrianus) spermatozoa

Summary The effect of different levels of osmolality and pH of lactose extender on the viability of Bactrian camel spermatozoa was investigated. Semen was collected from 10 Bactrian camel bulls using modified bovine artificial vagina. In experiment I, the extenders consisted of 9, 10, 11, 12 and 13% lactose with respective osmolalities of 290, 333, 350, 376 and 419 mOsm/kg and the pH of 6.9. In experiment II, 10% lactose extender with different levels of pH = 5.9, 6.9, 7.5, 7.9 and 8.9 were compared. All extenders contained 20% egg yolk and antibiotics. There were three replicates (ejaculates) for each trial. After dilution, semen was evaluated for progressive forward motility (PFM), plasma membrane integrity (PMI) and live percentage of sperm, at time 0, 4, 12 and 24 hrs after incubation at 4°C. Viability of sperm was similar among 9-11% lactose concentrations at time 0 and 4. PFM was compromised (<8%) at 10 and 11% lactose extenders at time 12. Although, PFM was greatest at time 0 (P<0.05) for the pH of 6.9, it reduced to 15% at time 4 (P<0.05). At the pH of 5.9-7.9, PMI and live percentage of sperm reduced at time 12 and 24, respectively (P<0.05). In conclusion, 9-11% lactose with the pH of 6.9 may consider as a suitable extender for the shortterm preservation (up to 4 hrs) of Bactrian camel semen maintained at chilled condition (4°C)