ABSTRACT
The present study aims to evaluate the occurrence and characterize Staphylococcus aureus in meat and meat products marketed in Mansoura, Egypt based on their antimicrobial-resistance pattern and production of enterotoxins. A total of 250 meat samples, categorized as 80 fresh beef samples besides 85 ground beef and 85 beef burger purchased from supermarkets and butchers' shops distributed in Egypt for isolation of Staphylococcus aureus. All isolates were screened for susceptibility to twelve antimicrobial discs. Minimal inhibitory concentration was carried out by twofold serial dilution in nutrient broth. Plasmid and genomic DNA| extraction were done. Polymerase chain reactions were performed for amplification of enterotoxin-encoding genes [sec and seg] Twenty five samples were isolated and identified as S. aureus. Sixty eight isolates were multidrug resistant since they were resistant to at least three different antimicrobial classes. Plasmids isolation from all isolates revealed that 76% of these isolates harbored plasmids. Fifteen isolates [60%] exhibited similar plasmid band size. The size of this plasmid was approximately 23 kbp. For seg gene, it was amplified in 8 isolates [32%] of S. aureus isolates at 550 bp. Five [63%] of the isolates harbored seg gene were multidrug resistant. On the other hand, none of the S. aureus isolates harbored sec gene. The present study confirmed the high prevalence of newly discovered enterotoxin genes [seg] in meat derived staphylococcus aureus and the association between the presence of this gene and multiple drug resistant phenomena
ABSTRACT
Aim: the present study aims to determine the efflux pump resistance by phenotypic and genotypic Methods
Methods: a total of 40 isolates of Pseudomonas aeruginosa were studied for antibiotic susceptibility pattern, , Effect of efflux pump inhibitors [reserpine, carbonyl cyanide mchloropheylhydorazone [CCCP] and omperazole] on the MIC of antibacterial agents, ethidium bromide [EtBr] efflux assay, outer membrane proteins, polymerase chain reaction for the amplification of resistance genes
Results: nearly most of the isolates were multiple resistant as they were resistant to most antimicrobial classes used in this study. CCCP was found to have the highest effect on decreasing the MIC of different antibiotics comparable with reserpine and omperazole. It was found that all tested Pseudomonas aeruginosa isolates extrude EtBr resulting in decrease in fluorescence over the time of assay. In Pseudomonas aeruginosa isolate No.3 and 14 only the control cells extrude EtBr resulting in significant loss in fluorescence. In presence of each of reserpine, CCCP and omperazole/e, an insignificant loss in fluorescence was observed, reflecting blockage of EtBr by these compounds at different levels. All the isolates produced high amount of outer membrane proteins with apparent molecular mass of 54 KDa and 50 KDa. These proteins may be designated as OprJ and OprM or OprN. MexA and MexB genes was detected and amplified in most of the tested isolates of Pseudomonas aeruginosa genomic and plasmid DNA. The amp/icons were visualized at 500 bp and 1000 hp respectively. While OprM gene was amplified successfully in the twenty tested isolates and the amp/icons were visualized at size of 900 bp
ABSTRACT
Urinary tract infections and their complications cause serious health problems affecting millions of people every year. Infections of the urinary tract are the second most common type of infection in the body. About 20% of women are especially prone to UTIs for reasons that are not yet well understood. UTIs in men are not as common as in women but can be very serious when they do occur. Accurate identification of bacterial isolates is an essential task of the clinical microbiology laboratory. Conventional identification methods of these infections lack the precision and the reproducibility, as well as they are time consuming because they rely on the growth of the bacteria. Some groups need days or even weeks to grow. Soon after the DNA becomes the worldwide common language, in this study, we compared the conventional microbiological diagnostic methods with the molecular based techniques. Our main focus was targeted to the PCR and sequencing of ribosomal markers. Our candidate in this study was 16S rRNA gene using different primer sets specifically designed to amplify different regions of our marker. We also focused on how much sequencing information is needed for blind identification of bacterial pathogens. In conclusion, the DNA sequencing based method provides a valuable tool for cheap and accurate diagnosis of Gram-negative bacteria in urinary tract infections which can be applicable in other infections
ABSTRACT
Background: Increased incidence of resistance to beta-lactams among members of the family Enterobacteriaceae has been reported worldwide. Extended spectrum beta-lactamase [ESBL] producing Gram-negative bacteria are becoming a major global concern and usually harbor plasmid-mediated enzymes of the TEM, SHV, OXA, PER, and CTX-M types. The aim of this study is to determine the prevalence of ESBL-producing Enterobacteriaceae in Mansoura hospitals and to molecularly characterize the ESBL-related bla genes, including blaTEM and blaCTX-M
Methodology: A total of 40 E. coli, 30 K. pneumoniae and 30 Proteus isolates were studied for antibiotic susceptibility pattern using different betalactam antibiotics and for the presence of ESBLs by combination of double-disc approximation test and inhibitor-potentiated disc-diffusion test. Subsequently, the hyper variable regions of beta-lactamase-encoding genes were amplified and sequenced using dye termination Sanger methodology to study the genetic variation among the clinical isolates
Results: All E. coli isolates were resistant to ampicillin, amoxicillin/clavulanate and cefadroxil. Regarding K. pneumoniae, all isolates were resistant to ampicillin, amoxicillin/clavulanate, cefadroxil, cefoxitin, cefuroxime and cefotaxime. Concerning Proteus species, all isolates were resistant to ampicillin, cefadroxil, cefotriaxone, cefuroxime and cefoperazone. In contrast 95% of E. coli isolates 80% of K. pneumoniae isolates and 90% of Proteus isolates were sensitive to imipenem. The detection of ESBLs by double-disc approximation test and inhibitor-potentiated disc-diffusion test was quiet different. Double disc approximation method lacks sensitivity. It showed false negative results in nearly 92% of the isolates that were concerned positive ESBLs producers by inhibitor-potentiated disc-diffusion test. PCR amplification and sequencing analysis revealed the presence of CTX-M and TEM type ESBLs in the tested isolates and could accurately characterize different types of blaTEM and blaCTX-M among the clinical isolates
Conclusion: Combined use of the conventional ESBLs screening methods and the molecular amplification of the ESBLs encoding genes followed by PCR based sequencing method provides a very valuable tool for identification and characterization of ESBLs producing E. coli, K. pneumoniae, and Proteus clinical isolates
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Aim: The present study was aimed to determine the antimicrobial resistance and Methicillin resistance gene of MRSA isolated from different clinical sources with a comparative study between phenotypic and genotypic methods in respect of accuracies
Methods: A total 49 isolates of MRSA were studied for antibiotic susceptibility pattern, oxacillin and cefoxitin disc diffusion test, SDS_PAGE analysis, DNA extraction and mecA resistant gene detection by PCR
Results: The study included 49 phenotypically detected MRSA isolates by convential methods. All MRSA isolates were resistant to cefoxitin. Although vancomycin was the first drug of choice in treatment for MRSA, it shows a certain resistant for 8.16% of the investigated isolates which is known as VRSA. The result of oxacillin disc diffusion test indicated that 43 isolates were MRSA, although all the tested isolates were considered MRSA according to the results of cefoxitin disc diffusion test. SDS-PAGE showed high degree of similarity among the banding patterns of MRSA. Detection of mecA gene reveled that, it was amplified on chromosomal DNA of 41 out of 49 isolates. Despite all isolates were proved to be a MRSA, only 83.67% gave positive results with PCR
ABSTRACT
Background: Klebsiella species cause 3-7% of all nosocomial infections, placing them in the top 10 of nosocomial bacterial pathogens
Materials: In this respect, we evaluated the differences in some quinolone resistance determinants among 70 clinical isolates of Klebsiella pneumoniae collected from Mansoura University Hospitals
Results: In the present investigation, some molecular typing techniques were applied on 70 isolates of K. pneumoniae isolated from Mansoura University Hospitals from different clinical lesions. The distribution of antibiotic resistance among the isolated strains showed high incidence of resistance to extended-spectrum cephalosporins [70 to 94.29%] and to quinolones [38.57 to 55.7 %] was also observed. Imipenem was the most active antibiotic so; it could be considered the drug of choice for treatment of infections caused by multi-resistant K. pneumoniae. Plasmid profiles of the tested strains appear to be diverse, although some similarities were found among tested strains. Sixty seven out of 70 strains contained plasmid DNA. PCR amplification was used to detect some quinolone resistance determinant genes such as gyrA, gyrB and Onr in the collected Klebsiella pneumoniae isolates. Using pyrosequencing technique, the sequenced region of gyrA gene was able to differentiate between resistant and sensitive strains however, the sequenced region of gyrB gene failed to differentiate between resistant and sensitive strains. Qnr gene was detected in all tested strains except strains No. 24 and 28
Conclusion: Using PCR and DNA sequencing of the target region of gyrA gene, we were able to differentiate between resistant and sensitive strains. While, amplification of another region of gyrB or Qnr genes failed to differentiate between the isolates. But, it could detect different types of mutations between the clinical isolates