Study of Genes Found in Streptococcus Agalctiae

Using the information found in the Gram Negative Enteric Baccilli and Gram Positive Cocci Reference books,

The Staphylococcus aureus bacteria belongs to the Staphylococcaceae family. It is small, round shaped, and non-motile. Staphylococcus aureus stains gram positive and can often be found in small clusters (Mandal, 2010). It often forms chains and is a large contributor of soft tissue infections. It is of a yellow color, hence the name ?aureus? which comes from the Latin term ?aurum? for gold (Orenstein, n.d.). Staphylococcus aureus is found in a few spots on the human body, such as the nasal passage, the skin, the oral cavity, and even the gastrointestinal tract. Staphylococci and Streptococci are two different strands of the bacteria and are very hard to distinguish from one another. In order to tell the difference between them, without a microscope, a catalase test needs to be performed. The test is undergone by adding 3% hydrogen peroxide to both samples. Since Staphylococci are catalase positive, meaning they produce catalase, they will produce O? while the Streptococci will not because Streptococci are catalase negative (Todar, n.d.).

Streptococcus pyogenes, also known as Group A streptococcus (GAS), is a β-hemolytic, Gram-positive bacterium that most commonly causes respiratory disease, including pharyngitis or tonsillitis, as well as skin infections such as impetigo and cellulitis. The organism is transmitted via respiratory droplets or by contact with fomites, and commonly infects young children. In addition to the common clinical presentations associated with S. pyogenes, some individuals develop the postinfectious sequelae of rheumatic fever and glomerulonephritis. Due to the severity of these medical consequences, prophylactic antibiotic use is often recommended for any patients with otherwise mild S. pyogenes infections (21).

Streptococcus Pyogenes is a very diverse bacteria with effects ranging from nothing or a mild sore throat, to flesh eating disease, causing death in 40-60% of patients. The major and most common illnesses associated with this bacteria

“Bacterial illness is a result of complex interactions between bacteria and the host. During evolution, humans developed many ways to protect themselves against bacterial pathogens. On the other hand, bacteria have developed strategies to evade, subvert or circumvent these defenses” (Sousa, 2003) “One of the most important characteristics of bacterial pathogenicity is the various strategies developed by prokaryotic organisms to use host molecules for their own benefit” (Sousa, 2003). “To accomplish this, bacteria have evolved elaborate control mechanisms to turn genes on and off, varying the transcriptional activator or

Group A. Streptococcus is a bacterium that causes many different types of infections. It is believed that at least 5-15% percent of the population are carriers of Group A Strep. These carriers tend to carry the bacteria on their skin or in their throats and usually remain asymptomatic.

It is not unusual for some healthy women to harbor Group B streptococcus bacteria in their rectum and vagina. These microorganisms do not usually cause disease when few in number, but when they grow in number and colonize these areas, bacterial infection can become severe.

Agrobacterium causes crown-gall disease, which is a neoplastic development that occurs due to the transfer of a DNA (T-DNA) portion from the bacterial tumor-inducing (Ti) plasmid to the host cell. The molecular machinery required for T-DNA transport into the host cell contains proteins that are encoded by the bacterial chromosomal virulence genes (chv) and by the Ti-plasmid virulence genes (vir). Although we know a lot about the functions of Agrobacterium Vir proteins, and about their role in T-DNA production and processing inside the bacterial cells, less is known about the system by which the T-DNA goes into the host cell. Only in the recent times we have begun exploring the functions

Streptococcus pyogenes is a very common bacteria found in humans. It is very transmissible and can be caught through the air via coughing or sneezing. This form of Strep. illness is referred to as Streptococcal pharyngitis, also known as Strep. throat, which can complicate into Scarlet Fever. It is also possible to be infected through abrasions of the skin, which can result in cellulitis, impetigo, or even necrotizing fasciitis. Aside from human to human contact, these bacteria can also be found in unpasteurized milk. There is no vaccine for Streptococcal infections, though antibiotics such as penicillin still work very well against them.

Streptococcus pneumoniae is found worldwide. The common host is the human body, in which it often does not cause disease but at other times it can cause diseses in particular, pneumonia. It also causes otitis media, bacteremia, meningitis, peritonitis, and sinusitis. The route by which this organism is spread is from human to human in the form of aerosol droplets. When inside the host the organism’s primary site of pneumococcal colonization is the nasopharynx. From this site it can aspire to the lungs, eventually spread to the blood and traverse the blood-brain barrier to the meninges, once inside the blood it can cause infections throughout the body. Symptoms of the disease include sudden

The SPI-2 type III secretion system is a multifunctional virulence system (Fig. 4) that is initiated following entry of bacteria into eukaryotic cells and facilitates bacterial growth in all cell types (Ochman et al.,1996;

Virulence Factors: The most important virulence factor of S. aureus is the specific surface proteins that allow the organism to attach to host proteins. The surface proteins of this bacterium allow it to attach to host proteins such as laminin and fibronectin, which form the extracellular matrix of epithelial and endothelial cells. S. aureus also produces a number of membrane damaging toxins that allow the organism to further invade and harm the host, of which the alpha- toxin is the most well studied and is the protein responsible for septic shock. The alpha- toxin is a protein that binds to a specific receptor in platelets and monocytes in humans, forming pores that eventually destroy the cell.

The pathogenesis of Streptococcus dysgalactiae is attributed to a combination of extracellular factors and properties such as adherence and biofilm formation. The aim of this work was to evaluate the influence of different factors, additives and bovine milk compounds on S. dysgalactiae biofilm formation, as the presence of the gfba gene by PCR. Additionally, extracellular DNA and the effect of DNaseI were evaluated in the biofilms yielded. Optimal biofilm development was observed when the pH was adjusted to 7.0 at 37 ºC. Additives as glucose and lactose reduced biofilm formation as bovine milk compounds tested. PCR assay showed

while the less virulent type II strains do not express CagA and harbor a nontoxic

The bacterium evolved by loosing its genes converting it from a free-living microbe into a pathogen. It needs the host’s nutrients in order to survive. The bacterium latches itself onto the host epithelial cells by a 160 kDa type 1 pilli. The pilli, located on a specific organelle on the polar region of the