The virulence pattern and the difficulties encountered in the diagnosis and
treatment of many bacterial infections have turned its dissemination a serious problem
of public health. It is essential, for an effective antimicrobial therapy, to have a precise
and early diagnosis, thereby decreasing the risk of severe and fatal cases. However,
many difficulties are found in conventional bacteriological diagnostic techniques due to
several factors: loss of bacterial viability, delay in bacterial cultivation and the
antibiotic therapy prior to the exam. The molecular biology methods are valuable tools,
especially in the case of serious infectious diseases. These technologies have the ability
to detect infectious agents with greater sensitivity and specificity without the need of
viable parasites in the biological sample, such as the polymerase chain reaction (PCR)
and its variations, the DNA microarray technology and proteomics analyzes. Some of
these methods are already available in laboratories, especially those in the private
network. However, the interpretation of the results requires differing and deep levels of
knowledge, imposing the need for training human resources in order to get a wider
dissemination and exploitation. This chapter describes the characteristics, pathogenicity,
epidemiology and methods of laboratory diagnosis of significant bacterial
infections and the achievements in molecular biology, which may be part of future
routine diagnostic tests and thus, contribute to the prevention and control of infectious
processes.
Keywords: Chlamydia trachomati, Helicobacter pylori, Infectious diseases,
Laboratory diagnostic, Neisseria meningitidis, Staphylococcus aureus.
