12- MRSA and VRE
What are some issues with VRE (Vancomycin Resistant enterococci)
*may be resistant to other antibiotics too - options vary - not a risk to general population -Colonizes in healthy individuals, who serve as the carriers for VRE -check via rectal swab -life threatening in long-term or compromised patients
MRSA
- Drug resistant bacteria -Methicilisan-resistant staph. aureus -Has ESBL -Resistant to commonly used B-lactam antibiotics
MRSA treatment
- IV vancomycin -New strains show antibiotic resistance even to vancomycin and teicoplanin: vancomycin intermediate-resistant staphylococcus aureus (VISA)
What are some issues found with MRSA?
- It is not a risk to the general population -It colonizes in healthy persons, who serve as the carriers -Can be checked via nasal swab
VRE Treatment
-Can be used with antibiotics other than vancomycin -Lab screening determines which antibiotics are effective Asymptomatic carries= don't usually need treatment -VRE Patients with urinary catheters: remove this when not needed
Name some bacterial cell "targets"
-Cell wall structure/biosynthesis -Protein synthesis -Nucleic acid metabolism -Membrane-active compounds
How is MRSA transmitted?
-Direct and physical person to person contact -Droplet nuclei from the mouth and nose
How is VRE transmitted?
-Direct person to person contact (stool, urine, blood) -not droplet nuclei from the mouth and nose -not usual from causal contact: touching, hugging, etc
VRE
-Drug Resistant bacteria - Vancomycin resistant enterococci -Has ESBL
VISA
-Drug resistant bacteria -Vancomycin intermediate-resistant staph. aureus -Has ESBL
VRE Prevention
-Gloves and gowns -Wash hands thoroughly after bathroom/ contact with VRE persons/substances -Frequently disinfect surfaces
MRSA Prevention
-Gloves and gowns -Wash hands well after using bathroom/ after contact w/ MRSA persons/substances -Frequently disinfect surfaces -Patient screening and isolation (?) -Prophylaxis (?)
Enterococcus
-Isolated from up 25% of healthy persons
What are some antibiotics that target the Cell wall structure/ biosynthesis of the bacteria?
-Natural penicillians -Semi-synthetic penicillians -Cephalosporins -Vancomycin
What is MRSA resistant to?
All B-lactams *Penicillian : - chromosomal mutation -Plasmid: weak B-lactasmase (penicillinase) *Methicillin: due to weak gene cassette -plasmid -borne transposon --> Visa--> van A gene (peptidoglycan change confers the vancomycin resistance)
Antibiotic therapy for CA-MRSA
B-lactam resistant BUT SUSCEPTIBLE to fluoroquinolones, trimethoprim/sulfamethoxazole tetracyclines and macrolides (for now- there are more)
How does PRSP encode antibiotic resistance?
Chromosomal mutation (pen binding protein), no B-lactamase
How does MRSA encode antibiotic resistance?
Chromosomal mutation (peptidoglycan), plamid (B-lactamase)
CA-MRSA
Community Acquired MRSA -"Newer" type, virulent -No co-morbidities -More susceptible to non B-lactam antibiotics= more choices -Serious soft tissue infections -Geneotyps differes from CA-MRSA
ESBL
Extended-spectrum B-lactamases
HA-MRSA
Health Care Associated MRSA -"Older" type -Multiple co-morbidities -Less susceptible to non B-lactam antibiotics --> fewer choices -Fewer serious soft tissue infections -Genotypes differ from CA-MRSA
When is MRSA life threatening?
In patients with.. -deep wounds -IV Catheters, entubations, etc. - secondary infection in immunocompromised patients
How does VISA encode antibiotic resistance?
Plasmid borne transposon (peptidoglycan change)
How does VRE encode antibiotic resistance?
Plasmid borne transposon (peptidoglycan change)
Antibiotic therapy for HA-MRSA
Resistant to B-lactams and -B-lactams, macrolides, fluoroquinolones -Clindamycin and trimethoprim/sulfamethoxazole choices: Vancomycin, teicoplanin, etc.
How many types of MRSA are there?
Two : HA-MRSA and CA-MRSA
Are Enterocci apart of the human flora?
Yes, especially in the -human gastrointestinal tract - especially the colon -female genital tract
