ABSTRACT
Purpose: The present study aimed to investigate the distribution of methicillin resistance as well as some virulence factors in S.aureus strains isolated from diabetic and non-diabetic patients by Phenotypic and genotypic methods
Methods: A total of fifty eight isolates were identified as S.aureus [41 isolates from diabetics and 17 isolates from non-diabetics] from infected wounds and abscesses in type I diabetic and non-diabetic patients admitted to 4 different hospitals located at Mansoura and Damietta, Egypt. Resistance to eight antimicrobial agents was detected using disk diffusion method. The isolates were screened for some virulence factors, namely hemolysins, lipases, lecithinase, haemagglutination, slime production and carotenoid pigment. Also, some virulence genes, namely hla, hlb, icaA, icaD, geh and methicillin resistance gene, mecA were also detected
Results: S.aureus was prevalent in 46% of collected specimens. The antibiotic sensitivity test showed that vancomycin was the most active antibiotics against tested strains. Total hemolytic activity was shown by 91% of tested strains. Lipase enzyme was produced by 65.5% of strains while 56.9% of tested strains produce lecithinase enzyme. Haemagglutination was observed in 82.8% of tested strains although 77.6% of strains were positive slime producers. About 93% of tested strains were pigmented. The hla gene was amplified in 33 strains while hlb and geh genes were distributed in almost all tested strains. Both icaA and icaD genes were detected and amplified in 96.5% of tested strains. On the other hand, methicillin resistance was detected in 86% of S.aureus strains
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
ABSTRACT
Background: Gram negative bacteria are responsible for numerous infectious diseases. These diseases can occur in and harm any part of the body, the skin, eyes and the nervous, cardiovascular, respiratory, gastrointestinal and urogenital systems
Methods: In the present study, some phenotypic and molecular typing techniques were applied on 108 strains of E. coli, 88 strains of Ps. aeruginosa and 8 strains of Serratia isolated from different clinical lesions in Mansoura University Hospitals, Egypt
Results: The distribution of antibiotic resistance among the isolated strains showed high incidence of resistance and imipenem was the most active antibiotic. Using the active pyocin typing, 72 strains of Ps. Aeruginosa could be typed into 35 pyotypes. Using PCR technique it was found that 84% of the 50 tested isolates were found to have at least one of the tested ESBLs. Also TolC and AcrA genes were present in all tested E. coli except 4 strains and did not present in Ps. aeruginosa except 4 strains. Plasmid profiles of 23 tested E. coli appear to be diverse. Also the prevalence of plasmids in 22 tested Ps. aeruginosa strains was lower than in tested E. coli therefore 59.1% of tested Ps. aeruginosa strains harbored plasmids. Using Pyrosequencing technique, the sequenced region of gyrA, gyrB and ParC were able to differentiate between the tested strains and neighbor-joining tree was constructed to determine relatedness between the isolated strains. Moreover, Molecular cloning of the whole sequence of bla-TEM, bla-SHV and bla-CTX-M was carried out experimentally to study the expression of these genes and determine which genes of them responsible for the resistance
Conclusion: Molecular-based typing methods of are more advantageous compared with phenotypic typing methods in terms of better discrimination and reproducibility. Significant genetic variation was observed among different strains represented by the diversity of their plasmid profiles. All molecular genetics methods for distinguishing organism subtypes are based on differences in the DNA sequence
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
ABSTRACT
Twenty patients with one of the thalassemia syndromes on regular blood transfusion and ten matched controls were subjected to clinical assessment, 12 lead ECG, serum ferritin level [FER], hemoglobin level [HB], serum electrolytes, echo Doppler examination, signal averaged ECG [SAECG] and 24 hours Holter monitoring. The results indicated that supraventricular and ventricular arrhythmias were much more common in patients group than control group; patients showed higher FER level, lower HB level but no significant difference in serum electrolytes. They also showed larger left ventricular and diastolic and end systolic diameters with no significant difference in ejection fraction. Corrected QT interval was longer in the patients group. SAECG was positive for late potentials in 20% of patients vs no one in the control group. Patients with late potentials [Gp A] were compared with patients with normal SAECG [Gp B]. Multiple regression analysis showed that older age, positive SAECG and lower ejection fraction, respectively, predict the occurrence of higher grades of arrhythmia. Patients with chronic hemolytic disorder on regular blood transfusion frequently had significant arrhythmias. High grade arrhythmias are more encountered with older age, presence of late potentials and lower left ventricular function
Subject(s)
Thalassemia , Blood TransfusionABSTRACT
The effect of six aminoglycoside antibiotics; namely, amikacin [Am], streptomycin [Sm], neomycin [Nm], kanamycin [Km], gentamicin [Gm] and tobramycin [Nn] on protease production by Pseudomonas aeruginosa was studied. Moreover, the possible interaction between isolated crude enzyme and tested aminoglycoside antibiotics was also investigated. Subinhibitory concentrations of aminoglycoside antibiotics produced a slight effect on bacterial growth, while protease production was inhibited at varying degrees. Maximum inhibition was produced by Sm, followed by Nm, Am and Gm. Kanamycin and tobramycin were of no effect on protease production. Pseudomonal protease significantly reduced bacterial activity of both Sm and Km against sensitive and resistant strains of Pseudomonas aeruginosa, whereas none of the tested aminoglycoside antibiotics could exhibit any change in protease activity
Subject(s)
Pseudomonas aeruginosaABSTRACT
The bacteriostatic activity of ampicillin-amikacin and ampicillin-gentamicin combinations was shown to be synergistic against the tested strain of Pseudomonas aeruginosa, fractional inhibitory concentration [FIC] index was 0.25. Pre-incubation of all tested aminoglycosides [gentamicin, tobramycin, kanamycin, amikacin and streptomycin] with the crude pseudomonal beta-lactamase, revealed neither inhibition nor stimulation of such enzyme. Beta-lactam antibiotics, especially ampicillin and benzyl penicillin, inhibited the activity of aminoglycoside-inactivating enzymes produced by Pseudomonas aeruginosa. The tested aminoglycosides and beta-lactams at subinhibitory concentrations were noninducible to beta-lactamase and aminoglycoside inactivating enzymes, respectively. Aminoglycoside-beta-lactam synergism against Pseudomonas aeruginosa was suggested to be in part due to aminoglycoside-inactivating enzyme inhibition by beta-lactams