Iraqi Journal of Medical Sciences








Vol. 9 Issue 4 October - December / 2011
Published on website | Date : 2016-04-07 10:19:36

A STUDY ON HEAVY METALS AND ANTIBIOTIC RESISTANCE OF STAPHYLOCOCCUS AUREUS ISOLATED FROM CLINICAL SPECIMENS

Abdul-Kareem H Abd, Ahmed R Abu-Raghif, Rafah A Samir


Abstract

Background:The trace heavy metals such as Cobalt, Zinc, Copper and Nickel play important roles in bacteria; they regulate a wide array of metabolic function as coenzyme or cofactors. However, some metals like arsenic, mercury and cadmium, are not essential for growth and extremely toxic. Understanding of metal resistance in Staphylococci in association with antibiotics resistance has progressed rapidly in the last years with well-established cadmium, mercury, antimony and arsenic resistance system encoded by plasmids.
Objective:To evaluate antibiotic and heavy metal resistance in Staphylococcus aureus isolates.
Methods: Thirty S. aureus isolates were collected from different clinical specimens. The minimum inhibitory concentration of thirty S. aureus isolates was determined for four types of antibiotics, which were tetracycline, gentamicin, cefotaxime and penicillin-G. Resistance of S. aureus isolates to heavy metals ions (Cobalt, Zinc, Mercury and Cadmium) were tested. Ethidium bromide was used as a curing agent with freshly growing S. aureus to study resistance features link with antibiotic and heavy metal resistance.
Results:The minimum inhibitory concentration of thirty S. aureus 83.3% of the isolates were resisting tetracycline 80% of the isolates were resisting gentamicin 93.3% of the isolates were resisting cefotaxime, and 80% of the isolates were resisting penicillin-G. While, 93.3% of isolates found to be resistant for Cobalt ions, 86.6% resisted Zinc ions, 86.6% resisted Mercury ions. While, 83.3% of isolates resisted Cadmium ions. Using Ethidium bromide as a curing agent showed two groups of cured colonies.
Conclusions:There is strong relationship between multiple antibiotic resistances and multiple heavy metal resistance In addition; there may be two to three types of plasmids depending on results obtained from curing experiment.
Key wards:Heavy metals, S aureus, antibiotics, resistance.


Full-text