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Resistance of staphylococci to penicillin-G and cloxacillin
Abstract:
Staphylococcus aureus and epidermidis species from patient cultures and hospital environmental samples were studied for resistance to Penicillin-G and Cloxacillin, a penicillinase resistant penicillin. Only 4--7% of the 232 Staphylococcus aureus strains were sensitive to Penicillin-G; 40--41% were sensitive to Cloxacillin. Patient strains (57) of Staphylococcus epidermidis were sensitive to Penicillin-G in 29% and to Cloxacillin in 53% of the cases. The incidence of sensitivity of the hospital strains (50) of Staphylococcus epidermidis to Penicillin-G was 78% and to Cloxacillin was 93%. In view of their high resistance to Cloxacillin, the strains were evaluated for sensitivity to Gentamicin, an alternate choice for antibiotic therapy. Approximately 90% of the Staphylococcus aureus strains were sensitive to Gentamicin while 99% of the Staphylococcus epidermidis strains were sensitive. This study indicates that differences may exist in regard to antibiotic resistance patterns in various localities and this should be evaluated.
Insights
Staphylococcus aureus and epidermidis exhibit high resistance to Penicillin-G and Cloxacillin. Gentamicin shows high effectiveness against these bacteria, suggesting it as a viable alternative antibiotic therapy.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Pharmacy
Background:
- Staphylococcus species are significant human pathogens.
- Antibiotic resistance in Staphylococcus poses a growing clinical challenge.
- Penicillinase-resistant penicillins like Cloxacillin are often used, but resistance is increasing.
Purpose of the Study:
- To assess the antibiotic resistance patterns of Staphylococcus aureus and Staphylococcus epidermidis.
- To evaluate the sensitivity of these strains to Penicillin-G, Cloxacillin, and Gentamicin.
- To determine the suitability of Gentamicin as an alternative therapy.
Main Methods:
- Bacterial isolates of Staphylococcus aureus and Staphylococcus epidermidis were collected from patient cultures and hospital environmental samples.
- Antibiotic susceptibility testing was performed using Penicillin-G and Cloxacillin.
- Further testing evaluated sensitivity to Gentamicin for strains showing resistance to Cloxacillin.
Main Results:
- A high resistance rate to Penicillin-G was observed in Staphylococcus aureus (93-96%) and Staphylococcus epidermidis (71% in patient strains, 22% in hospital strains).
- Cloxacillin resistance was also significant, particularly in Staphylococcus aureus (59-60%).
- Gentamicin demonstrated high efficacy, with approximately 90% of Staphylococcus aureus and 99% of Staphylococcus epidermidis strains being sensitive.
Conclusions:
- Staphylococcus aureus and Staphylococcus epidermidis display considerable resistance to Penicillin-G and Cloxacillin.
- Gentamicin is a highly effective antibiotic against both species, indicating its potential as an alternative treatment.
- Antibiotic resistance patterns may vary geographically, necessitating local evaluation.