Antibiotic resistance pattern of different escherichia coli phylogenetic groups isolated from human urinary tract infection and avian colibacillosis

The emergence and propagation of different phylogenetic groups of antimicrobial-resistant E. coli have become a worldwide health concern in human and veterinary medicine. Therefore, the evaluation of the phylogenetic distribution of antibiotic-resistant E. coli is important for therapeutic and economic purposes. The aims of this study were to determine phylogenetic groups and patterns of antibiotic resistance of E. coli strains isolated from human urinary tract infection and avian colibacillosis. A total of 50 E. coli isolates [25 from human urinary tract infection and 25 from avian colibacillosis] were characterized by culture and assigned as different phylogenetic groups [A, Bl, B2, and D] by triplex PCR assay. Kirby-Bauer disk diffusion method was used to assess the susceptibility of all isolates to ten antibiotics. Results showed that the majority of the human and poultry isolates belonged to phylogenetic groups A and B2 and phylogenetic group Bl of the avian pathogenic strain isolates were the most drug-resistant isolates. Most of the isolates were resistant to at least five antibiotics, and multiple drug resistance was observed in 98% of E. coli isolates. A high degree of resistance was seen against penicillin and erythromycin. According to the results of this study, multidrug-resistance among isolates and high relation between phylogenetic groups and resistance in both human and poultry isolates were observed

Evaluation of different methods to detect methicillin resistance in Staphylococcus aureus [MRSA]

The studies suggest that dogs living with human are potential risk of becoming MRSA carrier and increased risk of infections caused by MRSA. Phenotypic methods to detect methicillin resistance in Staphylococcus aureus [MRSA] are inadequate. The objective of the present study was to determine methicillin resistance in S. aureus by phenotypic susceptibility test [oxacillin disk diffusion, cefoxitin disk diffusion, oxacillin screen agar] and molecular methods [PCR as a gold standard] and the latex agglutination test for the detection of PBP2a and to evaluate the results of these tests for its sensitivity and specificity. A total of 100 swab samples were taken from muzzle site, in more contact with human, of dogs and MRSA were isolated. Oxacillin [1 micro g], cefoxitin [30 micro g] disk diffusion and oxacillin screen agar method were used. The isolates were also subjected to latex agglutination test for detection of PBP2a and PCR to detect mecA gene. By PCR 37% of isolates show the presence of mecA. Latex agglutination was found to be the most sensitive [97.29%] and cefoxitin disk diffusion to be the most specific [96.82%] tests for detection of MRSA. Our finding showed that combining oxacillin screen agar or cefoxitin disk diffusion with latex agglutination improves sensitivity and specificity to detect methicillin resistance S. aureus [MRSA] isolates

Restriction fragment length polymorphism genotyping of human staphylococcus aureus isolates from two hospitals in Urmia region of Iran using the coa Gene

Staphylococcus aureus has become an emerging public health concern. Markers that differentiate tissue-specific lineages are needed to trace the sources of strains. The aims of this study were to determine the genotypic characteristics of S. aureus isolates that are associated with skin and urinary tract infections using polymorphisms in the coagulase gene. Coagulase gene variants among 26 S. aureus isolates from human infected skin [n = 10] and urine [n = 16] samples were investigated by amplification of the repeat units encoding the hypervariable region of the coagulase gene. The amplicons ranged from 490-790 bp and were subjected to restriction fragment length polymorphism [RFLp] analysis with HaeIII. In total, 6 distinct RFLp banding patterns were observed, designated C1-C6.The C1 pattern predominated in skin and urine isolates. Notably, the C3, C5, and C6 patterns were present in isolates from urine, whereas the C2 and C4 genotypes were preferentially detected in skin sample isolates. These data demonstrate the widespread prevalence of certain genotypes and tissue-specific tendency of other genotypes, suggesting the existence of lineage- and tissue-specific genes that mediate the development of tissue-specific pathogenicities of S. aureus isolates.

Detection of neuraminidase activity in pseudomonas aeruginosa PAO1

Some properties of neuraminidase produced by Pseudomonas aeruginosa PAO1 growth in a defined medium [BHI] were examined and evaluated for its features. The obtained supernatant enzyme of P. aeruginosa PAO1 cultures was used in a sensitive fluorometric assay by using 2'-[4-methylumbelliferyl] alpha-D-N acetylneuraminic acid as substrate.As hydrolyzing MUN with neuraminidase; free N-acetylneuraminic acid and 4-methylumbelliferone were formed with a shift in the fluorescence spectra from 315/374 nm [substrate] to 365/450 nm [product]. Enzyme activity was then measured by the fluorescence of 4-methylumbelliferone at 450 nm. Among the culture media to determine the enzyme production, the highest production of P. aeruginosa PAO1 neuraminidase was found in BHI culture media. Neuraminidase production in P. aeruginosa PAO1 paralleled bacterial growth in defined medium [BHI] and was maximal in the late logarithmic phase of growth but decreased during the stationary phase, probably due to protease production or thermal instability. The neuraminidase of P. aeruginosa PAO1 possessed an optimum temperature of 56 °C and the activity was pH-dependent with maximal activity at pH 5. Heating the enzyme at 56 °C for 45 min in the presence of bovine serum albumin destroyed 33.1% of the activity while the addition of Ca[+2], EDTA and N-acetyl neuraminic acid [NANA] decreased activity markedly. Overall, the results indicated that neuraminidase of P. aeruginosa PAO1 is more an extracellular enzyme than K. pneumonia neuraminidase is