Abstract
Disinfectants play an important role in health careassociated
infection control by either minimizing or preventing
microorganism dissemination. This article to study the
morphological changes which may be related to the lose of
antibiotic resistance after disinfectant exposure using SEM.
Showed all isolates resistant to ampicillin, amoxicillin, cloxacillin,
cephalexin, tetracycline, doxycycline, rifampin, chloramphenicol,
trimethoprim cefotaxime and erythromycin, while one of burn
isolates was susceptible for gentamicin, chloramphenicol and
trimethoprim, and 15 of burn, 6 of wound, 5 of ear, and all urine
isolates were susceptible to gentamicin using Kirby-Bauer
method.
The MICs of four common in use disinfectants (Hexatane,
Dettol, Savlon and Povidone – Iodine) were determined for all
isolates. The results showed that the MICs of Hexatane ranged
from (64–512) μg/ml, Dettol (2048–16384) μg/ml,
Savlon (4096:40960)–(32768:327680) μg/ml and for Povidone –
Iodine MICs were (8192–32768) μg/ml. It has been found that
burn and urine isolates were more resistant to disinfectants than
wound and ear isolates. According to the effect of subMICs of
disinfectants at different exposure patterns on antibiotic
resistance, the results showed lose of resistance to tetracycline,
doxycycline, rifampin, chloramphenicol, cefotaxime and
trimethoprim in %72, %72, %68, %22, %28 and %36 of isolates,
respectively. The results of SEM micrograph showed normal
morphology and small sized bacteria with nub formation on some
of them when exposed to dettol, and shape changes in cells with
bulging in exposed to Povidone-iodine, while elongation and
deformation were recorded in some cells in exposed to
Savlon(chlorohexidine/ cetrimide) and Hexatane (chlorohexidine/
gluconate), respectively.