Pulsed field gel electrophoresis & plasmid profile of Pseudomonas aeruginosa at two hospitals in Tehran, Iran.
OBJECTIVE
Pseudomonas aeruginosa is a common cause of nosocomial infections and exhibits innate resistance to a wide range of antibiotics. This study was undertaken to determine the resistance patterns of P. aeruginosa isolates recovered from patients at two hospitals in Tehran, to investigate the presence of plasmids and to genetically characterize them by pulsed field gel electrophoresis (PFGE).


METHODS
The susceptibility of 104 isolates of P. aeruginosa to 13 different antibiotics was determined by agar disk diffusion method. The alkaline lysis method was used for plasmid extraction. PFGE technique was optimized for DNA fingerprinting of isolates.


RESULTS
The isolates showed resistance to 13 different antibiotics ceftizoxime (99%), lomefloxacin (94.3%), ceftazidime (59.6%), ticarcillin (50%), ceftriaxone (44.3%), cefoperazone (37.5%), tobramycin (34.6%), piperacillin and gentamicin (33.7%), carbenicillin (25%), amikacin (22%), ciprofloxacin (15.4%) and imipenem (2.9%). Plasmids were detected in 31 isolates (29.8%) that produced 15 different patterns. In total, 84 DNA banding patterns were detected by PFGE. The dominant PFGE type, Pattern A with 14 isolates was found at both hospitals. The remaining isolates were grouped in B, C, D and PF1-PF80. The majority of isolates with the identical plasmid profiles and resistance patterns produced closely related DNA fingerprints by PFGE.


CONCLUSIONS
Isolates in pattern A were distributed widely at both hospitals and the environment. Absence of plasmids in majority of isolates indicated low typeability and discriminatory power of this technique.
Nikbin
V S
VS
Department of Biology, Faculty of Science, Alzahra University,Tehran, I.R., Iran.
Abdi-Ali
A
A
Feizabadi
M M
MM
Gharavi
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016172:DNA Fingerprinting; D016521:Electrophoresis, Gel, Pulsed-Field; D006761:Hospitals; D006801:Humans; D007492:Iran; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics*
D000900:Anti-Bacterial Agents