Prevalence of genes encoding Bi-component leukocidins among clinical isolates of methicillin-resistant staphylococcus aureus

Staphylococcus aureus has been recognized as a major human pathogen and is the major cause of nosocomial infections. Gamma-toxin, leukocidin and other bi-component toxins are a family of proteins encoded by the hlg and luk-PV, respectively. Panton-Valentine leukocidin [PVL] is an example of these toxins and causes leukocyte destruction and tissue necrosis. The aim of this study was to determine the prevalence of bi-component leukocidin in Methicillin - Resistant Staphylococcus aureus [MRSA] isolates in staphylococcal infections. Collectively, 143 isolates of S. aureus were obtained from Tehran University of Medical Sciences hospitals and confirmed with biochemical tests. Then polymerase chain reaction was used to detect luk-PV loci and luk-E/D. Coagulase gene was used as internal control. The antibiotic susceptibility patterns of isolates were determined using disk diffusion method. Out of 149 S. aureus isolates 24.2% were luk-PV positive and 73.8% were luk-E/D positive. There was PVL-positive MRSA isolates with high prevalence in evaluated hospitals. The diseases from these bacteria are with extensive necrosis, leucopenia and even death. We desire that, prevent from progress and death by diagnosis and right treatment

[ effect of sub-minimum inhibitory concentration [S-MIC] of ciprofloxacin and ampicillin on hemolysin activity of Escherichia coli]

Sub-minimum inhibitory concentration [S-MIC] can induce changes in morphology, virulence factors and biochemical properties of bacterial pathogens. The goal of this study is to determine the Sub-MIC effect of ciprofloxacin and ampicillin on the haemolytic activity of E. coli. Two clinical isolates of E. coli with high haemolytic activity was selected. Changes in haemolytic activity of the isolates was assessed after exposing them to MIC and Sub-MIC of ciprofloxacin and ampicillin. Ciprofloxacin decreased haemolytic activity at 1/2, 1/4 and 1/8 Sub-MIC, whereas ampicillin showed no effect on haemolytic activity. We conclude that Sub-MIC concentrations of ciprofloxacin decreased the haemolytic activity of E. coli, whereas ampicillin had no such effect

[Cytolethal distending toxin [CDT] produced by Campylobacter jejuni and Campylobacter coli isolated from chikens by tissue culture method in Isfahan]

Campylobacter jejuni is one of the most common bacterial cause of diarrheal disease in humans throughout the world. Contamination is mainly linked to the consumption of undercooked food products contaminated with Campylobacters. The most characterized toxin proposed is CDT, which has been detected in several Campylobacter species. With regard to the role of broiler chickens in transmission of campylobacter to human and the possible role of CDT in the pathogenesis of Campylobacter, detection of Campylobacter producing CDT is necessary. In this study 368 rectal swabs were collected from chikens. All the specimens were cultured on Skirrows and Blood agar and incubated in microaerophilic conditions at 42°C for 48-72 h. Hella cell was applied to detect CDT in C. jejuni and coil. Campylobacter strains were isolated from 114 [31%] of 368 chicken [101 C. jejuni and 13 C. coli]. Toxin production in C. jejuni and C. coil was 94% and 76.9% respectively. It seems that the majority of C. jejuni and C. coli produce CDT although C. jejuni produces a higher titer