Virulence, resistance genes, and transformation amongst environmental isolates of Escherichia coli and Acinetobacter spp.
The association of verotoxic E. coli and Acinetobacter spp. with various antibiotic-resistant, diarrhogenic, and nosocomial infections has been a cause for concern worldwide. E. coli and A. haemolyticus isolated on a number of selective media were screened for virulence factors, antibiotic resistance, and transformation of resistance genes. Out of 69 E. coli isolates obtained, 25 (35.23%), 14 (20.30%), and 28 (40.58%) were positive for Vtx1&2, Vtx1, and Vtx2, respectively, 49 (71.015%) for extendedspectrum beta-lactamases (ESBLs), 34 (49.28%) for serum resistance, 57 (82.61%) for cell surface hydrophobicity, 48 (69.57%) for gelatinase production, and 37 (53.62%) for hemolysin production. For the 14 A. haemolyticus isolates, only 2 (14.29%) in each case from all the samples investigated were positive for Vtx1, Vtx2 and Vtx1&2 respectively, 8 (57.14%) for ESBLs, 7 (50.00%) for serum resistance, 11 (78.57%) for cell surface hydrophobicity, 4 (28.57%) for gelatinase production, and 8 (57.14%) for hemolysin production. Although transformation occurred among the E. coli and Acinetobacter isolates (transformation frequency: 13.3 × 10(-7) -53.4(-7)), there was poor curing of the plasmid genes, a confirmation of the presence of stable antibiotic-resistant genes (DNA concentration between 42.7 and 123.8 microgram) and intragenetic transfer of multidrugresistant genes among the isolates. The isolates were potentially virulent and contained potentially transferable antibiotic resistance genes. Detection of virulence factors, antibiotic resistance genes, and transformation among these isolates is a very significant outcome that will influence approaches to proactive preventive and control measures and future investigations. However, continued surveillance for drug resistance among these bacteria and further investigation of the mechanism of action of their virulence factors are a necessity.
Applied Sciences Faculty, Cape Peninsula University of Technology, Cape Town, South Africa. jameshamuel@yahoo.com
Hamuel James
HJ
Doughari
Patrick Alois
PA
Ndakidemi
Izanne Susan
IS
Human
Spinney
S
Benade
D000150:Acinetobacter / Q000235:genetics / Q000302:isolation & purification*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D001770:Blood Bactericidal Activity; D002473:Cell Wall / Q000737:chemistry; D024881:Drug Resistance, Bacterial; D004783:Environmental Microbiology; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D022761:Gene Transfer, Horizontal; D057927:Hydrophobic and Hydrophilic Interactions; D010957:Plasmids; D014169:Transformation, Bacterial; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000378:metabolism
D001427:Bacterial Toxins; D037521:Virulence Factors; D001618:beta-Lactamases