Antimicrobial Activity of Andrographis paniculata against Profiled Multidrug-Resistant Isolates from Asymptomatic Bacteriuria

Asymptomatic bacteriuria (ASB) is the presence of actively multiplying bacteria in urine of any individual without any visible signs or symptoms of urinary tract infection (UTI) such as painful urination, frequent urination, fever, abdominal pain, cloudy or strong smelling urine. In this research on antimicrobial activities of Andrographis paniculata against profiled multi drug resistant clinical isolates from asymptomatic bacteriuria, seventy (70) clinical isolates collected from apparently healthy female students of Renaissance University Enugu were used. The isolates were identified and biochemical tests were carried out according to standard methods. The antibiotic susceptibility tests of the isolates was done using the single disk diffusion method according Kirby-Bauer. The leaves of Andrographis paniculata were extracted by cold maceration using methanol as the solvent and their phytochemical analysis done. The antimicrobial susceptibility pattern of the extract against the clinical isolates were determined using the agar disk diffusion technique. The minimum inhibitory concentration (MIC) and the Minimum Bactericidal Concentration (MBC) were done using standard method. The plasmid profiling of the 16 multidrug isolates that were resistant to the extract and ciprofloxacin (positive control) was done using standard method. Furthermore, plasmid curing was done using sodium dodecyl sulpfate (SDS). Their antibacterial susceptibility testing of the resistant isolates were repeated with the leaf extract to confirm their curing. The result of the study showed that 70 identified isolates occurred in the frequency of 15 K. pneumoniae, 10 S. aureus, 16 E. coli, 5 E. fecalis, 2 P. mirabilis, 4 P. aeruginosa, 7 E. aerogenes, 1 S. saprophyticus, 2 S. epidermis, 8 E. cloacae. The antibiotic susceptibility result showed that the isolates showed varying degrees of resistance to Nitrofurantoin, Gentamicin, Cefotaxime, Ofloxacin, Ampiclox, Cefixime, Ceftriaxone Sulbactam, Amoxicillin clavulanate, Nalidixic acid, Cefuroxime, Levofloxacin, Imipenem, The phytochemical analysis of the leaves showed that they contain bioactive compounds such as tannins, alkaloids, saponins, steroids, flavonoids, terpenoids, proteins, carbohydrates, reducing sugars, anthocyanin, and phenols. The extract of A. paniculata had the highest invitro antimicrobial activity against K. pneumoniae (31.60±0.85mm at 100mg/ml) while the least antimicrobial activity was on S. aureus (4.83±0.00 mm at 50mg/ml). The minimum inhibitory concentration of the extract of A. paniculata showed inhibition of the bacterial isolates at 3.125mg/ml and 12.5mg/ml for strains of E. cloacae and P. aeruginosa. The minimum bactericidal concentration of A.paniculata was 6.25mg/ml against strains E. cloacae. Plasmid profile gel images of 16 selected bacterial isolates that were resistant to extract and ciprofloxacin showed 10 samples out of 16 selected bacterial isolates have mild resistant genes in them. The result of the repeated antimicrobial susceptibility after curing with SDS showed that 8 of the bacterial resistant isolates became susceptible to the extract and or ciprofloxacin to which they previously showed resistance prior to curing while the rest of the selected bacterial isolates were not affected by the curing agent as they still maintained their resistance and this showed that their resistance could be plasmid mediated. The result in our findings showed the relationship of plasmids with antibiotic resistance and that methanol extract of A. paniculata has broad-spectrum antimicrobial activity and can serve as natural therapeutic agent against asymptomatic bacteriuria pathogens.