mohammad reza arabestani dr

Pharmaceutical residuals like antibiotics in livestock products and their consumption by humans from food chain can lead to the spread of bacteria resistant to antibiotics. The aim of the current study was to investigate antibiotic resistance and determine the prevalence rate of genes encoding extended spectrum beta-lactamase (ESBLs) in Acinetobacter strains isolated from raw foodstuffs. In this study, 300 samples from protein foodstuffs (mutton, beef, chicken, hamburger, hot dog, sausages) and dairy foodstuffs (raw milk and cheese) were prepared and investigated in terms of contamination with Acinetobacter baumannii from July 2015 to November 2016. The isolated bacteria were identified by biochemical tests to species level and confirmed by the PCR technique via blaOXA-51 gene. Antibiotic resistance of the isolates was studied using the diffusion disc method. Also, the presence of ESBLs enzymes in the isolates wa s done phenotypically and genetically through PCR and combined disk tests. The results showed that 43 strains of A. baumannii were isolated from the protein and dairy foodstuffs, 93% from protein foodstuffs and 7% from dairy foodstuffs. Also, 30% of the isolates had multidrug- resistance (MDR). Further, the findings of PCR illustrated that the prevalence of genes encoding ESBLs in the isolates were: TEM 21%, PER 23.5%, VEB 18.5 % and SHV35%. Foodstuffs can act as a food source for A. baumannii that can lead to transferring and spreading genes encoding antibiotic resistance to humans.

Clindamycin is one of the selective drugs for treatment of staphylococcal infections. Molecular methods can complete phenotypic methods to diagnosis induction resistance to clindamycin. The aim of this study was to identify the genes responsible for the resistance to clindamycin and erythromycin, and determine their antibiotic resistance pattern. 100 isolates of Staphylococcus epidermidis and Staphylococcus saprophyticus were isolated from 466 different clinical specimens using biochemical tests. Using the disc diffusion method, Antibiogram susceptibility test was conducted to determinate lincosamides and tetracycline resistance pattern. Then ermA, ermB, ermC and msrA genes were identified and investigated by PCR method. Out of 100 strains of coagulase-negative staphylococci isolated from clinical specimens, 5 isolates were identified as S. saprophyticus (5%) and 55 isolates of S. epidermidis (55%), respectively. Out of the 5 isolated of S. saprophyticus, 2 (40%) isolates were resistant to methicillin and one (20%) isolate had D phenotype. In addition, 1 isolate had ermA gene and 1 isolate had ermB. Out of the 55 isolates of S. epidermidis, 25 (45.45%) isolates were resistant to methicillin, of which nine (36%) isolates had D phenotype. Also, 4 (16%) isolates had ermA gene, 3 (12%) isolates had ermB, 6 (24%) isolates had ermC and 1 (4%) isolate was carrying the msrA. The phenotypic pattern of resistance to macrolide- lincosamides groups does not have a high degree of accuracy in detecting methicillin-resistant MLSB strains.

As one of the fat-soluble vitamins, vitamin K, can in some cases have intrinsic inhibitory effects on the activity of methicillin-resistant Staphylococcus aureus. The aim of this study, was to determine the effect of vitamin K2 on the expression of mecA and blaZ genes in Multi Drug Resistant Methicilin Resistance S. aureus isolates.
76 clinical isolates of methicillin-resistant S.aureus were isolated by phenotypic tests. For treatment of isolates, concentrations of 1, 10, 50, 100, 200, 300 and 500 μg / ml of vitamin K2 and different time intervals were used. The q-PCR method was used to quantitatively evaluate the genes. It was also used to analyze the results of REST 2008 V3 and SPSS 16 software.
The expression of blaZ and mecA genes was reduced only at a concentration of 500 μg / ml of vitamin K2. Additionally, the 48 and 72 hours incubation times had the best effect on the effect of vitamins on the genes studied. In the isolates from clinical specimens, ulcers and urine reduced the expression of mecA and blaZ genes. Also, there was a significant relationship between incubation time and clinical specimen type on decreasing the expression of the desired genes (P≤0.01, P≤0.05).
In accordance to the results of this study, the use of vitamin K2 can play an important role in the control of methicillin-resistant Staphylococcus aureus strains.

Backgrounds and Aim: Staphylococcus aureus biofilms are involved in a multitude of serious chronic infections. Production of biofilms is a defensive-invasive process controlled and regulated by the aap and icaR genes. The expression levels of these genes play an important role in the formation of biofilm. The aim of this study was to investigate the expression of icaR and aap regulatory genes in clinical isolates of S. aureus resistant to methicillin and gentamicin.
In this analytical study, among 285 samples, we detected 100 isolates of methicillin resistant and 82 isolates of gentamicin resistant S. aureus. Resistant strains were evaluated for the presence of biofilm regulatory genes. The expression levels of regulatory genes were measured by real-time PCR method. We used SPSS software 16 for statistical analysis and also REST 2008 V3 software for analysis of quantitative results.
Among 100 methicillin resistant and 82 gentamicin resistant isolates of S. aureus the highest expression levels of icaR and aap genes were detected in the smears obtained from the wounds and catheters. Moreover, a different pattern of gene expression was observed in multidrug resistant strains in comparison to the strains with lower rate of resistance. Also, there was a significant relationship between the presence and activity of regulatory genes and biofilm formation in different samples (p≤0 / 05).
Considering the frequency of biofilm producing strains of S. aureus in the smears from the catheters and wounds and also increased gene expression, appropriate therapeutic measures should be considered for methicillin and gentamicin resistant of S. aureus.