an investigation into the antibacterial activities of medicinal plants ...

5.1.5 Standard antimicrobial sensitivity patterns of Gram-positive
and Gram-negative bacteria
All the bacterial strains used in this study were clinical isolates collected from the
NHLS (Main Branch) Port Elizabeth. Antibiotic sensitivity patterns were received with
all of the isolates. The MIC’s of the plant extracts were determined using a selection
of these bacterial strains. Table 8a & 8b display the antibiotic sensitivity patterns of
the selected Gram-positive and Gram-negative bacterial strains, respectively.
The following ten antibiotics were used for sensitivity testing of the Gram-positive
bacteria namely:
penicillin (P10), co-amoxacillin (AMC30), cloxacillin (OX1), ofloxacillin (OFX50),
erytromycin (E15), clindamycin (DA2), vancomycin (VA30), fucidin (FD10),
cotrimoxazole (FXT25), and tetracycline (TE30) (Table 8a).
All the S. aureus strains were resistant to penicillin and sensitive to the rest of the
tested antibiotics except for strain [no. 4] that was resistant to erythromycin (Table
8a).
All the MRSA strains were resistant to penicillin, co-amoxicillin, cloxicillin, and
erythromycin but sensitive to the other antibiotics tested except strain [no. 3] that was
resistant to cotrimoxazole (Table 8a).
All the strains of S. pyogenes were sensitive to all the antibiotics (penicillin,
erythromycin, cotrimoxazole and tetracycline) tested. All E. feacalis strains similar to
S. pyogenes were sensitive to penicillin and erythromycin however; all the E. feacalis
strains were resistant to cotrimoxazole and tetracycline (Table 8a).
Table 8b displayed the antibiotic sensitivity patterns of the Gram-negative bacterial
strains with the following ten antibiotics:
ampicillin (AML10), co-amoxacillin (AMC30), cefazolin (KZ30), cefuroxime (CXM30),
ceftriaxone (CRO30), ceftazidime (CAZ30), gentamycin (GN 10), amikacin (AK30),
ofloxacillin (OFX5) & cotrimoxazole (FXT25).
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