MRSA ST398: Difference between revisions

Revision as of 06:36, 16 February 2025

Methicillin-resistant Staphylococcus aureus (MRSA)

File:MRSA ST398 Staphylococcus aureus VISA 2.jpg

Scanning electron micrograph of MRSA bacteria.

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that is resistant to many antibiotics, including methicillin, penicillin, and amoxicillin. MRSA is a type of Staphylococcus aureus, a common bacterium that can cause a range of illnesses, from minor skin infections to life-threatening diseases such as pneumonia, bloodstream infections, and surgical site infections.

History

MRSA was first discovered in 1961 in the United Kingdom, shortly after the introduction of methicillin. It has since become a major public health concern due to its resistance to multiple antibiotics and its ability to cause outbreaks in healthcare settings and the community.

Epidemiology

MRSA infections are more common in hospitals and other healthcare facilities, where they are known as healthcare-associated MRSA (HA-MRSA). Community-associated MRSA (CA-MRSA) infections occur in otherwise healthy individuals who have not been recently hospitalized or undergone medical procedures.

Pathogenesis

MRSA is able to resist methicillin and other beta-lactam antibiotics due to the presence of the mecA gene, which encodes a penicillin-binding protein (PBP2a) that has a low affinity for these antibiotics. This allows the bacterium to continue synthesizing its cell wall in the presence of methicillin.

Clinical Manifestations

MRSA can cause a variety of infections, including:

Skin and soft tissue infections, such as abscesses, boils, and cellulitis.
Pneumonia, particularly in patients with underlying lung disease.
Bacteremia and sepsis, which can lead to endocarditis and other serious complications.
Surgical site infections, which can complicate recovery from surgery.

Diagnosis

Diagnosis of MRSA is typically made by culturing the bacteria from a sample taken from the infected site and testing for antibiotic susceptibility. Molecular methods, such as PCR, can also be used to detect the presence of the mecA gene.

Treatment

Treatment of MRSA infections depends on the severity and location of the infection. Options include:

Vancomycin, which is often used for serious infections.
Linezolid, which can be used for skin infections and pneumonia.
Daptomycin, which is used for bloodstream infections and right-sided endocarditis.

Prevention

Preventive measures include:

Hand hygiene and the use of personal protective equipment in healthcare settings.
Screening and decolonization of patients and healthcare workers who are carriers of MRSA.
Proper wound care and hygiene in community settings to prevent the spread of CA-MRSA.

Related pages

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-MRSA ST398
+== Methicillin-resistant Staphylococcus aureus (MRSA) ==
-Methicillin-resistant *Staphylococcus aureus* (MRSA) ST398 is a strain of the bacterium *Staphylococcus aureus* that is resistant to methicillin and other beta-lactam antibiotics. This particular strain, known as sequence type 398 (ST398), is notable for its association with livestock, particularly pigs, and has been referred to as "livestock-associated MRSA" (LA-MRSA).
+[[File:MRSA_ST398 Staphylococcus_aureus_VISA_2.jpg|thumb|right|300px|Scanning electron micrograph of MRSA bacteria.]]
-==History and Emergence==
+'''Methicillin-resistant Staphylococcus aureus''' ('''MRSA''') is a [[bacterium]] that is resistant to many antibiotics, including methicillin, penicillin, and amoxicillin. MRSA is a type of [[Staphylococcus aureus]], a common bacterium that can cause a range of illnesses, from minor skin infections to life-threatening diseases such as pneumonia, bloodstream infections, and surgical site infections.
-MRSA ST398 was first identified in the early 2000s in the Netherlands and has since been detected in various countries around the world. It emerged as a significant public health concern due to its ability to colonize and infect humans who are in close contact with livestock, especially pigs. The strain was initially discovered in pig farmers and their families, highlighting the zoonotic potential of MRSA ST398.
-==Genetic Characteristics==
+== History ==
-MRSA ST398 belongs to the clonal complex 398 (CC398) and is characterized by the absence of the *SCCmec* type IV element, which is commonly found in community-associated MRSA strains. Instead, it often carries the *SCCmec* type V or other types. The strain is also known for its lack of the Panton-Valentine leukocidin (PVL) toxin, which is associated with virulence in other MRSA strains.
-==Epidemiology==
+MRSA was first discovered in 1961 in the United Kingdom, shortly after the introduction of methicillin. It has since become a major public health concern due to its resistance to multiple antibiotics and its ability to cause outbreaks in healthcare settings and the community.
-MRSA ST398 is primarily associated with livestock, particularly pigs, but it has also been found in other animals such as cattle, poultry, and horses. Human infections are typically linked to direct contact with these animals or their environments. The strain has been reported in Europe, North America, and Asia, with varying prevalence rates depending on the region and the density of livestock farming.
-==Transmission==
+== Epidemiology ==
-Transmission of MRSA ST398 occurs through direct contact with colonized or infected animals, as well as through contaminated environments. Human-to-human transmission is less common but can occur, particularly in healthcare settings or among individuals with close contact with colonized persons.
-==Clinical Manifestations==
+MRSA infections are more common in [[hospital]]s and other healthcare facilities, where they are known as healthcare-associated MRSA (HA-MRSA). Community-associated MRSA (CA-MRSA) infections occur in otherwise healthy individuals who have not been recently hospitalized or undergone medical procedures.
-In humans, MRSA ST398 can cause a range of infections, from mild skin and soft tissue infections to more severe conditions such as pneumonia and bloodstream infections. However, it is often less virulent than other MRSA strains, partly due to the absence of certain virulence factors like PVL.
-==Diagnosis==
+== Pathogenesis ==
-Diagnosis of MRSA ST398 involves microbiological culture and susceptibility testing to confirm methicillin resistance. Molecular typing methods, such as multilocus sequence typing (MLST), are used to identify the specific sequence type 398.
-==Treatment==
+MRSA is able to resist methicillin and other beta-lactam antibiotics due to the presence of the mecA gene, which encodes a penicillin-binding protein (PBP2a) that has a low affinity for these antibiotics. This allows the bacterium to continue synthesizing its cell wall in the presence of methicillin.
-Treatment of MRSA ST398 infections involves the use of antibiotics to which the strain is susceptible. Common options include vancomycin, linezolid, and daptomycin. The choice of antibiotic depends on the severity of the infection and the susceptibility profile of the isolate.
-==Prevention and Control==
+== Clinical Manifestations ==
-Preventive measures focus on reducing the risk of transmission from animals to humans. This includes implementing good hygiene practices in livestock farming, using personal protective equipment, and conducting regular screening of animals and workers. In healthcare settings, standard infection control measures are essential to prevent the spread of MRSA ST398.
+MRSA can cause a variety of infections, including:
+* Skin and soft tissue infections, such as [[abscess]]es, boils, and cellulitis.
+* [[Pneumonia]], particularly in patients with underlying lung disease.
+* [[Bacteremia]] and sepsis, which can lead to [[endocarditis]] and other serious complications.
+* Surgical site infections, which can complicate recovery from surgery.
+== Diagnosis ==
+Diagnosis of MRSA is typically made by culturing the bacteria from a sample taken from the infected site and testing for antibiotic susceptibility. Molecular methods, such as PCR, can also be used to detect the presence of the mecA gene.
+== Treatment ==
+Treatment of MRSA infections depends on the severity and location of the infection. Options include:
+* [[Vancomycin]], which is often used for serious infections.
+* [[Linezolid]], which can be used for skin infections and pneumonia.
+* [[Daptomycin]], which is used for bloodstream infections and right-sided endocarditis.
+== Prevention ==
+Preventive measures include:
+* Hand hygiene and the use of personal protective equipment in healthcare settings.
+* Screening and decolonization of patients and healthcare workers who are carriers of MRSA.
+* Proper wound care and hygiene in community settings to prevent the spread of CA-MRSA.
+== Related pages ==
-==Also see==
-* [[Methicillin-resistant Staphylococcus aureus]]
-* [[Livestock-associated MRSA]]
 * [[Antibiotic resistance]]
-* [[Zoonotic diseases]]
+* [[Staphylococcus aureus]]
+* [[Infection control]]
-{{MRSA}}
+* [[Healthcare-associated infection]]
-{{Antibiotic resistance}}
-[[Category:Staphylococcus aureus]]
 [[Category:Antibiotic-resistant bacteria]]
-[[Category:Zoonotic pathogens]]
+[[Category:Staphylococcaceae]]