Isolation and Identification of Pathogenic Bacteria from Soil Mixed with Hospital Wastes

Abstract

Objective: Hospital solid wastes when not incinerated (nor waste-waters are scientifically treated) remain

as sources of a myriad of pathogenic microorganisms.

Methods: A total of 960 waste samples (soil mixed with waste) were collected from waste disposal site of

the hospital. After successful growth, bacteria were sub-cultured in nutrient agar slants for preservation.

Biochemical characteristics of isolated bacteria were done for identification of bacteria.

Results: A total of 150 collected waste soil samples yielded 103 bacterial colonies, as 65 single and 38

mixed colonies, while 47 samples had no microbial growth. Methicillin resistant S. aureus (MRSA),

vancomycin resistant enterococci (VRE) and Pseudomonas aeruginosa isolates were in numbers, 28, 19

and 18, respectively. Of 103 colonies, 63 and 40 were from wastes of wards and ICUs. Invariably, MRSA

strains were isolated, as single or mixed colonies. The average minimum inhibitory concentration (MIC)

range against oxacillin was recorded as 16 ?g/mL for MRSA, and Vancomycin 16 ?g/mL for VRE and 8 ?g/

mL gentamicin for P. aeruginosa.

Conclusions: Site specific variation and seasonal variations underplay prevalence of different types of

nosocomial spread of opportunistic pathogenic bacteria.