styling verbatim with background color

Question

I am using pandoc to convert Markdown documents containing code blocks to PDF, and the intermediate TeX surrounds the code with \begin{verbatim}...\end{verbatim}. How can I stylize and format these sections to have a background color or a frame around it? I've tried fancyvrb, but the background color does not extend behind the text itself.

I've tried using the verbatim package and after reading the manual was able to modify \verbatim@processline to change the font color or add text in front of each line: \def\verbatim@processline{\fbox{\$ \the\verbatim@line}\par}. I would like to this for the entire chunk and modify other properties (frame, centering, etc) in the future. I thought the best way to do this would be to add a \begin{shaded} into \verbatim and add \end{shaded} into endverbatim. However, I run into an error when I do that:

\makeatletter
\def\verbatim{{\begin\{shaded\}}\begingroup\@verbatim 
\frenchspacing\@vobeyspaces\verbatim@start}
\def\endverbatim{\endtrivlist\endgroup{\end\{shaded\}}}
\makeatother

And the error message:

! Missing \endcsname inserted.
<to be read again>
                   \protect
l.1 \begin{verbatim}

1. Is there a way to insert enclose the verbatim text in an environment that I can stylize later?
2. If not, is there a better way of stylizing the verbatim environment? I cannot change to listings or similar packages that use \begin{lstlisting} since pandoc automatically inserts \begin{verbatim}?

MWE:

\documentclass{beamer}
\usepackage{xcolor, framed}
\definecolor{shadecolor}{RGB}{255,0,0}

\begin{document}

\begin{frame}[fragile]

\begin{verbatim}
Shade this text block
Shade this too
\end{verbatim}

\begin{shaded}
\begin{verbatim}
Shaded text here
And also here
\end{verbatim}
\end{shaded}

\end{frame}

\end{document}