9 Antibiotic resistance problems in food animals Flashcards
Which 4 bacteria?
+ hvad er de resistente overfor?
- Staphylococcus aureus (methicillin resistant)
- Escherichia coli (ESBL-producers)
- Campylobacter (fluoroquinolone- and macrolide resistant)
- Salmonella enterica (multi-resistant)
MRSA in production animals
• First discovery:
cow with mastitis in 1970
• Until 2004 very few descriptions of MRSA in milk from
cows despite:
• S. aureus is an important mastitis pathogen
• Cows are often treated with beta-lactams
• LA-MRSA in production animals
hvad gør den?
Prævalens?
Risikofaktorer?
- Colonization – not infection
- Very high prevalence (~100%) within contaminated farms
- Risk factors
- Antibiotic use (tetracycline) and zink
- Poor hygiene (veal calves)
- Large size herd
- Purchase of animals from MRSA-positive farms
LA-MRSA in humans:
Hvad gør den?
smitte?
• Temporary colonization
• Human-human transfer is rare
• Low morbidity and mortality – but can cause serious
infections
• Risk factor:
• Contact to farms with pigs or veal calves
ESBL
An enzyme, which can hydrolize all β-lactams except
carbapenems (+ inactivated by clavulanic acid)
• Often plasmid-encoded, so spreads easily between
bacteria
ESBL
hvor findes det?
• Occurs in Enterobacteriaceae, primarily E. coli and Klebsiella spp but also in Salmonella and other species
• ESBL-producing bacteria are often resistant to other
antibiotic classes (on same plasmid)
ESBL indikator?
- Indicator: resistance to 3. generation cephalosporins, e.g. cefpodoxime and cefotaxime
- ESBL can be encoded by many different genes, primarily CTX-M, TEM, SHV and CMY types
Hvor er ESBL et problem?
Hovedsageligt i fødevarer
Hvornår skal man bekæmpe problemet med ESBL?
Rational use of antibiotics (especially cephalosporins,
fluoroquinolones and amoxi/clav)
• A voluntary ban of cephalosporin use in Denmark
since 2010 appeared to have an immediate effect
Campylobacter
Hvad er den?
• Gram-negative, curved, microaerophilic bacteria
Campylobacter
Hvor findes den?
• In the GI and genital tract of many different animal species
• Often a commensal in animals – but pathogenic in
humans
Campylobacter
Hvad gør den?
• Most common cause of gastroenteritis in the Western world
– potential cause of serious disease in immunocompromised
Campylobacter
Hvilke arter?
• C. jejuni
• 90-95% af Campylobacter incidents in humans
• Widespread in many animals species, in particular
poultry
• C. coli
• 5% of human Campylobacter cases
• Animals: primarily in pigs
Treatment of Campylobacter infections
- Usually no treatment (self-limiting disease)
- Serious disease
- First choice: erythromycin (macrolide)
- Second choice: ciprofloxacin (fluoroquinolone)
- Alternatives: tetracyclines/gentamicin
Antibiotic resistance in Campylobacter – most
important mechanisms:
• Fluoroquinolone (FQ) resistance
• Macrolide resistance
• Fluoroquinolone (FQ) resistance
• Point mutations in gyrA, encoding DNA gyrase A,
which is important for DNA-replication
→ Target modification: FQ cannot bind and replication continues
• Macrolide resistance
• Point mutations in 23S rRNA or ribosomal proteins L4
and L22, which are important for protein synthesis
→ Target modification: macrolides cannot bind and
protein synthesis continues
