oa Molecular Diagnosis and Vaccines - Plasmid profile of multidrug resistant Pseudomonas aeruginosa strains in a burn unit
Pseudomonas aeruginosa is an important nosocomial pathogen, especially in individuals who are immunocompromised. This study investigates pseudomonas infections in burn wounds of patients at the Menoufiya University Hospital. Pseudomonas isolates were identified to the species level using automatic Sensititre, subjected to antibiotic susceptibility testing. Pseudomonas aeruginosa was the predominant (56.5%) species of Pseudomonas while mixed excellent group, Pseudomonas putida and Pseudomonas fluorscens constituted 19.6%, 15.2% and 8.7% of the isolates respectively. All Pseudomonas isolates were resistant to sulphamethoxazole trimethoprim (SXT), amoxycillin (AML), ampicillin + sulbactam (SAM), cefepime (CP), tetracycline (TE). Most of the strains were resistant to erythromycin (E) (91.3%), amoxycillin + clavulanic acid (AMC) (74.9%), ceftriaxone (CRO) (63%), azetreonam (ATM) (56.5%).Most of the strains were sensitive to amikacin (AK), tobramycin (TOB), gentamicin (CN), cefoperazone (CFP), and piperacillin (PRL) (91.3%, 89.2%, 69.6%, 58.7%, 56.6%) in this descending order of activity. Twenty isolates (43.4%) were ? lactamase producer, out of these isolates, 16 strains (80%) contained plasmids, while 4(20%) were plasmidless. Extended spectrum ? lactamase (ESBLS) was demonstrated in 4(8.6%) of isolates. Plasmid profile analysis showed that 18 isolates (39.1%) harboured plasmids with molecular weight ranging from 1.4 140 MDa. The number of plasmids, ranged from one to five, 8 strains (44.4%) contained 3 plasmids while 7 (38.9%) had one plasmid. 2(11.1%)had 2 plasmids, and one (5.5%) contained 5 plasmids. Resistances to AK, TOB and ATM were associated with the existence of large molecular weight plasmids. Moreover, resistance to increasing number of antibiotics was associated with high molecular weight plasmids. In conclusion, the burn wound represents a susceptible site for opportunistic colonization and multidrug resistant strains, Pseudomonas aeruginosa infection is particularly problematic, plasmid may be responsible for resistance to antibiotics. Resistance to ESBLS is an important problem in Egypt. Implementation of infection control measures may help in reducing further transmission of Pseudomonas clones within the burn units.
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