V Lakshmi1, T Satheeshkumar, G Kulkarni. 1. Department of Microbiology, Nizam's Institute of Medical Sciences, Punjagutta, Hyderabad - 500 082, Andhra Pradesh, India.
Abstract
PURPOSE: Chromogenic media are increasingly being used as versatile tools in early differentiation and identification of bacterial isolates from clinical specimens. We have evaluated the Urichrome II, a newly introduced chromogenic medium, for its utility as a primary isolation and identification medium for urinary microbial isolates. MATERIALS: This study included 5497 consecutively collected midstream and/or catheter catch urine samples obtained from patients attending several clinical services. They were inoculated on blood, MacConkey, cystine lactose electrolyte deficient, and Urichrom II agar plates for isolation of uropathogens. RESULTS: The Urichrom II medium allowed the growth, and primary identification, of the predominant uropathogens like E.coli, Klebsiella spp. and Enterobacter spp. (KES group). The different coloured colonies produced by the breakdown of the chromogenic substrates by the specific enzymes of the bacteria were very useful in the presumptive identification of these organisms even from mixed cultures by the colour differences of the colonies. The medium also supported growth and differentiation of gram positive organisms like Staphylococcus aureus and enterococci. CONCLUSIONS: Urichrom II can be used as a primary culture medium for predominant uropathogens like E.coli, KES group and enterococci. It is an easy to use primary screening medium that considerably reduces the daily workload and thus minimizes or limits the use of identification tests.
PURPOSE: Chromogenic media are increasingly being used as versatile tools in early differentiation and identification of bacterial isolates from clinical specimens. We have evaluated the Urichrome II, a newly introduced chromogenic medium, for its utility as a primary isolation and identification medium for urinary microbial isolates. MATERIALS: This study included 5497 consecutively collected midstream and/or catheter catch urine samples obtained from patients attending several clinical services. They were inoculated on blood, MacConkey, cystine lactose electrolyte deficient, and Urichrom II agar plates for isolation of uropathogens. RESULTS: The Urichrom II medium allowed the growth, and primary identification, of the predominant uropathogens like E.coli, Klebsiella spp. and Enterobacter spp. (KES group). The different coloured colonies produced by the breakdown of the chromogenic substrates by the specific enzymes of the bacteria were very useful in the presumptive identification of these organisms even from mixed cultures by the colour differences of the colonies. The medium also supported growth and differentiation of gram positive organisms like Staphylococcus aureus and enterococci. CONCLUSIONS: Urichrom II can be used as a primary culture medium for predominant uropathogens like E.coli, KES group and enterococci. It is an easy to use primary screening medium that considerably reduces the daily workload and thus minimizes or limits the use of identification tests.