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Table 1 Antibacterial activity of the biosurfactant extracts (1.00 mg mL−1) against a panel of Gram-negative and Gram-positive bacterial isolates

From: Characterisation and antimicrobial activity of biosurfactant extracts produced by Bacillus amyloliquefaciens and Pseudomonas aeruginosa isolated from a wastewater treatment plant

Organism (strain number) Source Antibacterial inhibition zone diameter (mm) ± SD
Surfactin extract
(0.26 ± 0.09 mg mL−1)
Rhamnolipid extract
(1.12 ± 0.08 mg mL−1)
Gram-negative target organism
 Escherichia coli (ATCC 417373) ATCC 13 ± 0 13.5 ± 0.4
 E. coli (ATCC 13706) ATCC 10 ± 0 29.3 ± 0.9
 Enteroinvasive E. coli (ATCC 43892) ATCC 15 ± 0 22.7 ± 2.1
 GEnteropathogenic E. coli (B170) ATCC 18.3 ± 0.5 20.3 ± 0.5
 Enterohaemorhagic E. coli (O157:H7) ATCC 13.7 ± 0.5 13.7 ± 0.5
 Enterotoxigenic E. coli (H10407) ATCC 17.7 ± 1.2 13 ± 0
 Enteroaggregative E. coli (3591-87) ATCC 12.3 ± 0.5 24.3 ± 1.2
 Klebsiella pneumoniae (ATCC 10031) ATCC 14 ± 1.6 13.5 ± 0.5
 Salmonella typhimurium (ATCC 14028) ATCC 25.3 ± 1.2 20.3 ± 0.5
 Serratia marcescens (ATCC 13880) ATCC 12.7 ± 0.9 14 ± 0
 K. pneumoniae (P2) Clinical 13 ± 0.8 11.7 ± 0.9
 K. pneumoniae (P3) Clinical 13.3 ± 0.2 8.3 ± 0.5
 Salmonella enterica (SE19) Environment 12.5 ± 0.5 14 ± 0
 Acinetobacter sp. (F1S6) Environment 12.3 ± 0.5 13 ± 1.4
 Serratia sp. (SM14) Environment 11.7 ± 0.9 14.3 ± 1.2
 Serratia sp. (L8) Environment 12.5 ± 0.5 9.8 ± 0.8
 Enterobacter sp. (E11) Environment 11.3 ± 0.5 13 ± 0.8
 Enterobacter sp. (E22) Environment 14.2 ± 0.6 13 ± 0.8
 E. coli (K4CCA) Environment 14.5 ± 0.5 17.7 ± 1.9
 K. pneumoniae (k2a) Environment 15.3 ± 0.5 13.7 ± 0.5
Gram-positive target organism
 O Staphylococcus aureus (ATCC 25923) ATCC 14.7 ± 0.5 13.7 ± 0.5
 B. cereus (ATCC 10876) ATCC 10.3 ± 0.5 13 ± 0.8
 B. cereus (LMG 13569) ATCC 13 ± 0.8 17 ± 1.4
 Enterococcus faecalis (S1) Clinical 18.7 ± 0.9 10.7 ± 0.5
 Enterococcus faecalis (S2) Clinical 18.3 ± 1.2 21.7 ± 2.4
 G,O,P,TMRSA (Xen 30) Clinical 15.3 ± 0.5 13.3 ± 0.5
 Bacillus cereus (ST18) Environment Inactive 22.3 ± 0.9
 Enterococcus sp. (C513) Environment 12.3 ± 0.5 15.7 ± 0.5
 Micrococcus sp. (AQ4S2) Environment 14 ± 0 14 ± 1
 S. aureus (C2) Environment 11.5 ± 0.5 14 ± 0
 S. aureus (C3) Environment 12 ± 0 11 ± 0
  1. The surfactin and rhamnolipid extracts were observed to be at 32.8 and 34.4% purity, respectively
  2. Values are the means ± standard deviations (SD) of triplicate measurements; ATCC American Type Culture, O resistant to Oxacillin, G resistant to Gentamicin, T resistant to Tetracycline, P resistant to Penicillin G