[Tex/LaTex] Tabular content spilling over right column margin

marginstables

tabular content spilling over right column margin. What's going on here? How can I fix it?

enter image description here

\documentclass[a4paper,12pt]{article}

\author{Peter Cao}
\date{}
\usepackage[font=small,labelfont=bf,tableposition=top]{caption} %apparently needs to come first or options clash with other packages will occur

\usepackage[x11names,dvipsnames]{xcolor} %for use in color links



\usepackage[hyphens]{url}
\usepackage[colorlinks=true,linkcolor=Blue4,citecolor=blue]{hyperref}
\usepackage[hyphenbreaks]{breakurl}
\usepackage{a4wide}
\usepackage{graphicx}

\usepackage[version=3]{mhchem}

\usepackage[T1]{fontenc} %for > and < in text mode
\usepackage{tikz}
\mhchemoptions{arrows=pgf-filled}

\usepackage{booktabs} %for top, middle and bottomline

\usepackage{multirow} %multi column and row spanning

\usepackage{amsmath}


\usepackage{cite}

\usepackage{multirow}
\usepackage{tabularx}




\usepackage{siunitx}

\usepackage{fancyhdr}
%\usepackage{fancyheadings} seems to be obsoleted by fancyhdr

\usepackage{comment}
\usepackage{multicol}


\usepackage{lastpage}

\newcommand{\ignore}[1]{} %a null macro which gobbles up comments, and thus acts as a tool for in-line commenting.


\usepackage{blindtext}




\begin{document}

\begin{multicols}{2}

\subsection*{Results}

{\small
\begin{tabularx}{\columnwidth}{l | c | c}
\toprule
Characteristic & \multicolumn{2}{c}{Result}\\
 \cmidrule(l){2-3}
 & Seaweed isolate & Coral isolate \\
\cmidrule(r){1-1} \cmidrule(l){2-3}
Cell shape & Rod & Rod\\
Gram stain & $-$ & $-$\\
Oxidase & $+$ & $-$\\
Catalase & $+$ & $-$\\
MSA & Growth & No growth\\
Anaerobic & Growth (weak) & No growth\\
Motility & & \\
Indole production & & \\
Hugh \& Leifsons & & \\
\bottomrule
\end{tabularx}
}

\blindtext

\end{multicols}

\end{document}

Updated version demonstrating shrinkage issues:

\documentclass[a4paper,12pt]{article}

\usepackage{booktabs} %for top, middle and bottomline
\usepackage{multirow} %multi column and row spanning
\usepackage{multicol}
\usepackage{graphicx}

\begin{document}

\begin{multicols}{2}

\subsection*{Results}


{\noindent
\resizebox{\columnwidth}{!}{%
\begin{tabular}{@{} l c c @{}}
\toprule
Characteristic & \multicolumn{2}{c}{Result}\\
 \cmidrule{2-3}
 & Seaweed isolate & Coral isolate \\
 \midrule
Cell shape & Rod & Rod\\
Gram stain & $-$ & $-$\\
Oxidase & $+$ & $-$\\
Catalase & $+$ & $-$\\
Anaerobic & Growth (weak) & No growth\\
Motility & & \\
Indole production & & \\
Hugh \& Leifsons & & \\
MSA & Growth & No growth\\
Growth in absence of salt & & \\
Colony pigmentation & White & White \\
\bottomrule
\end{tabular}
}
}



\end{multicols}

\end{document}

enter image description here

Best Answer

I already showed you in the other examples what to do ...

\documentclass[a4paper,12pt]{article}
\date{}
\usepackage[font=small,labelfont=bf,tableposition=top]{caption} %apparently needs to come first or options clash with other packages will occur

\usepackage[x11names,dvipsnames]{xcolor} %for use in color links
\usepackage[hyphens]{url}
\usepackage[colorlinks=true,linkcolor=Blue4,citecolor=blue]{hyperref}
\usepackage[hyphenbreaks]{breakurl}
\usepackage{a4wide}
\usepackage{graphicx}

\usepackage[version=3]{mhchem}

\usepackage[T1]{fontenc} %for > and < in text mode
\usepackage{tikz}
\mhchemoptions{arrows=pgf-filled}

\usepackage{booktabs} %for top, middle and bottomline

\usepackage{multirow} %multi column and row spanning

\usepackage{amsmath}
\usepackage{cite}
\usepackage{multirow}
\usepackage{tabularx}
\usepackage{siunitx}
\usepackage{fancyhdr}
%\usepackage{fancyheadings} seems to be obsoleted by fancyhdr
\usepackage{comment}
\usepackage{multicol}
\usepackage{lastpage}

\newcommand{\ignore}[1]{} %a null macro which gobbles up comments, and thus acts as a tool for in-line commenting.
\usepackage{blindtext}
\begin{document}

\begin{multicols}{2}

\subsection*{Results}

\noindent
\resizebox{\columnwidth}{!}{%
\begin{tabular}{@{} l | c | c @{}}
\toprule
Characteristic & \multicolumn{2}{c}{Result}\\
 \cmidrule(l){2-3}
 & Seaweed isolate & Coral isolate \\
\cmidrule(r){1-1} \cmidrule(l){2-3}
Cell shape & Rod & Rod\\
Gram stain & $-$ & $-$\\
Oxidase & $+$ & $-$\\
Catalase & $+$ & $-$\\
MSA & Growth & No growth\\
Anaerobic & Growth (weak) & No growth\\
Motility & & \\
Indole production & & \\
Hugh \& Leifsons & & \\
\bottomrule
\end{tabular}%
}

\bigskip
\blindtext

\end{multicols}

\end{document}

enter image description here

it is also possible to fiddle with a surrounding tabularx or a \parshape to get "unbalanced" columns:

enter image description here