Staphylococcus
Biochemical characteristics of Staphylococcus: catalase test
- Catalase test - Staphylococci produce catalase - This is tested by addition of hydrogen peroxide to bacteria on a glass slide, and gas bubbles are observed
S. hyicus (coagulase-variable) in pigs causes
- Exudative epidermitis (greasy-pig disease) - Arthritis
Staphylococcus lipase pathogenic effect
breaks down lipids
S. sciuri host
cats, dogs and other animals
S. felis
cats/otitis externa, skin infections
S. xylosus
cattle, sheep/milk, cats, poultry, pigs, horses/skin
S. epidermidis host
cattle/milk; dogs/horses/wound infections
S. chromogenes
cattle/milk; pigs, poultry/skin
Staphylococci in poultry - Bumblefoot diagnosis
clinical signs
Tick pyemia in lambs diagnosis
clinical symptoms & isolation of S. aureus bacteria
Exudative epidermitis / greasy pig disease treatment and control
- early treatment with topical and systemic antibiotics - topical antiseptics - isolate infected pigs - clean and disinfect surfaces - wash sows with antiseptic before farrowing
General characteristics of Staphylococcus spp
- Gram-positive cocci - clusters resembling a bunch of grapes - about 1 um in diameter - most are salt tolerant - resistant to lysozyme - stable in the environment - cause pyogenic infections
Multidrug resistance staphylococcal infections in animals
- MDR to familiar drugs: trimethoprim-sulfonamides, fluoroquinolones, macrolides, tetracyclines, lincosamides (clindamycin) - therefore, vets are left with drugs such as: Rifampin, Chloramphenicol, Aminoglycosides - newer antimicrobial agents: linezolid, ceftaroline, daptomycin and tigecycline have been developed for methicillin-resistant Staphylococcus aureus in humans
Staphylococcal diseases of vet importance - COAGULASE-POSITIVE
- S. aureus - S. pseudintermedius - S. hyicus (coagulase-variable) - S. intermedius - S. schleiferi subsp. coagulans
Note: the Staphylococcus intermedius group consists of:
- S. pseudintermedius - S. intermedius - S. delphini
Otitis externa in dogs
- S. pseudintermedius may be primary or secondary cause - need to treat all contributing factors of the conditions e.g. mites, fungi
Examples of COAGULASE-NEGATIVE staphylococci
- S. sciuri - S. epidermidis - S. xylosus - S. chromogenes - S. caprae - S. equorum - S. felis
Exudative epidermitis / greasy pig disease predisposing factors
- agalactiae in the sow - concurrent infection - weaning
Methicillin-resistance (MR)
- an alternative binding site for Beta-lactam antibiotics (penicillin-binding protein 2A (PBP2A)) is encoded for by mecA/C genes - Mec A/C genes confer resistance to Beta-lactam antibiotics (e.g. penicillin, ampicillin and cephalosporins and others) - MR is used as a marker for resistance to all Beta-lactam antibiotics including penicllins, cephalosporins and carbapenems
Exudative epidermitis / greasy pig disease clinical signs
- anorexia, depression, fever - extensive, exfoliative, non-pruritic dermatitis with a greasy exudate - piglets under 3 weeks of age may die within 24-48 hrs
Bovine staphylococcal mastitis treatment and control
- antimicrobial agents: parenteral antibiotics (IM, SC), intramammary antibiotics, antibiotics - Cephalosporins, cloxacillin, erythromycin, penicillin (if organism is susceptible), penicillin combined with novobiocin, pirlimycin, tetracyclines, tylosin, tilmicosin - Oxytocin: in combination with hand stripping - improve animal husbandry and milking practices - maintain a good milking machine/system
S. aureus in poultry causes
- arthritis and septicemia in turkeys - Bumblefoot - omphalitis
Diagnosis of Staphylococcus: biochemical tests, molecular/genetic testing
- biochemical tests: catalase, coagulase, DNase, latex agglutination tests - molecular/genetic testing - PCR: to detect spa gene codes for Protein A production, to detect MRSA - mecA and mecC gene which encodes an alternative PBP2A binding site; MLST and PFGE, RFLP identify clonal strains; MALDI-TOF
Summary: Staphylococcus spp. can be cultured on
- blood agar plates - common selective and differential media include: MSA, Purple agar
S. aureus in pigs causes
- botryomycosis of mammary glands - impetigo on mammary glands
Summary: Staphylococcus also causes
- bovine mastitis - tick pyemia in lambs - botryomycosis in horses and sows - exudative epidermitis/greasy pig disease - bumblefoot in chickens - in humans: similar to to those for dogs and cats; food poisoning
Staphylococcus cell-associated virulence factors
- capsule - protein A - adhesins
Staphylococcus exoenzymes virulence factors
- catalase - coagulase - lipase - elastase - DNase - hyaluronidase - staphylokinase
Exudative epidermitis / greasy pig disease diagnosis
- clinical signs: exudative dermatitis - isolation and ID of S. hyicus
Biochemical characteristics of Staphylococcus: coagulase
- coagulase - a major virulence factor - observing for agglutination when rabbit plasma is combined with a pure colony - Prothrombin - (Coagulase) -> Thrombin - Fibrinogen - (Thrombin) -> Fibrin
Pyoderma in dogs clinical signs
- dermatitis and folliculitis (rarely systemic) - starts as papular lesions -> pustules and small intradermal abscesses - deep skin lesions (furuncles/large haemorrhagic bullae) may rupture -> fistulous tracts with pus
Staphylococcus selective and differential plates: Purple agar
- differentiates S. aureus from S. pseudintermedius - contains: Bromocresol purple as an indicator, 1% maltose
Staphylococcus selective and differential plates: Mannitol Salt Agar (MSA)
- differentiates staphylococci from coliforms and streptococci: aids in diagnosis in mastitis - differentiates between S. aureus/S. pseudintermedius (pathogenic) and non-pathogenic
Summary: Methicillin-resistant staphylococcal infections are
- difficult to treat - may display multidrug resistance
Bovine staphylococcal mastitis diagnosis
- direct microscopic examination of the milk - culture
Pyoderma in dogs treatment
- drain abscesses - depends on whether lesions are deep or superficial - topical antiseptics - topical and/or systemic antibiotics - staphage lysate
Summary: Methicillin resistance is encoded by the mec A/C gene
- encodes for penicillin-binding protein (PBP2A) which is an alternative binding site for Beta-lactam antibiotics - used as an indicator of resistance to Beta-lactams
Staphylococcus exotoxins virulence factors
- enterotoxins - toxic shock syndrome toxin - exfoliative toxin - hemolysins - leukocidin
Staphylococcal diseases in humans
- food poisoning - transmission: readily transferred to food by carriers handling food - foods implicated: rich foods - custard and cream-filled baked goods, puddings, and creamy salad dressings; salads prepared with mayo-based dressings e.g. potato and egg salads; salty foods, ham - risk is increased by: temperature abuse: food at room temp for too long and poor hygiene e.g. poor hand washing, etc. - exfoliating or Scalded Skin syndrome
Cultural characteristics of Staphylococcus
- grow on non-enriched media (non-fastidious) - facultative anaerobes, non-motile - oxidase-negative - non-spore forming - rapid growth in 18-24 hrs at 37 C - moderately sized - some are pigmented (yellowish/golden especially for some S. aureus)
Exudative epidermitis / greasy pig disease transmission
- highly contagious - a commensal of the vaginal mucosa and skin of healthy sows - enter skin through abrasions
Botryomycosis in horses and sows diagnosis
- history, epidemiology and clinical signs - lesion consists of fibrous tissue with foci of pus and sinus tracts
S. intermedius in horses and pigeons causes
- in horses: isolated from the nares - in pigeons: isolated from the upper respiratory tract
Methicillin-resistant staphylococcal (MRS) infections in animals
- initially began as a major problem in hospitals: hospital-associated methicillin-resistant S. aureus (HA-MRSA) - has become a major problem in vet med and animal health: livestock-associated methicillin-resistant S. aureus (LA-MRSA) - transmission between people and pets including vet personnel has been recorded - MR isolates may also be multi-drug resistant (MDR) - MDR isolates are resistant to 3 or more classes of antimicrobial agents
Staphylococci in poultry - Bumblefoot clinical signs
- lameness - decreased food intake and growth rate - economic losses
Staphylococcus general characteristics
- major opportunistic pathogen - associated pyogenic infections - mainly involved in skin and soft tissue infections (SSTI)
Antibiotic sensitivity testing is important due to high occurrence of antimicrobial resistance (AMR):
- many genes associated with antimicrobial resistance - major problem in vet med - S. aureus (MRSA), S. pseudintermedius (MRSP) and some CoNS (MRCoNS) can display methicillin-resistance
S. aureus in goats causes
- mastitis - dermatitis
S. aureus in sheep causes
- mastitis - tick pyemia in lambs - benign folliculitis in lambs - dermatitis
Bovine staphylococcal mastitis pathogenesis
- neutrophils and macrophages are impaired - chronic inflammation - occasionally gangrenous
Staphylococcus: Hemolysis on blood agar variable, depending on species:
- non-hemolytic (S. hyicus) - single hemolysis - double hemolysis
Botryomycosis transmission
- post-surgery - trauma with contamination
Tick pyemia in lambs treatment
- prophylactic antibiotics e.g. long-acting tetracycline given to lambs starting at 1 week of age - tick-control measures
Summary: Staphylococcus common clinical conditions in dogs and cats
- pyoderma - otitis externa - mastitis - endometritis - cystitis - osteomyelitis - wound infections
Staphylococcal infections in dogs and cats: Staphylococcus pseudintermedius is associated with
- pyoderma - otitis externa - other suppurative conditions: mastitis, endometritis, cystitis, osteomyelitis, wound infections
Botryomycosis in horses and sows lab diagnosis
- samples - pus, skin biopsy - culture and microscopy
Botryomycosis in horses
- schirrhous cord a few weeks post castration - commonly located in the limbs near the point of the elbow
Biochemical characteristics of staphylococcus: slide vs tube coagulase test
- slide test for BOUND coagulase - tube test for UNBOUND coagulase
Staphylococci in poultry - Bumblefoot treatment
- soaks - scab removal - antibiotic ointments - dressings
Staphylococcal species
- species: >50 species of Staphylococcus described to date - most important species in vet med include: S. aureus - coagulate-positive; S. pseudintermedius - coagulate-positive; S. hyicus - coagulase-variable
Diagnosis of Staphylococcus: specimens, direct microscopy, culture
- specimens: pus, milk or other suitable specimens - direct microscopy: observation of Gram-positive cocci - culture: Blood agar (BAP): observe for colony morphology, hemolysis; Selective media: mannitol salt agar (MSA), purple agar, Baird Parker agar (BPA), Chromogenic agars: CHROMagar MRSA, Brilliance MSRA
Botryomycosis in horses and sows treatment and control
- surgical excision - prolonged systemic antibiotics after sensitivity testing - good hygiene
Pathogenic Streptococcus spp
- tend to be species-adapted - mastitis, metritis, polyarthritis, meningitis, pneumonia
Staphylococcus transmission and predisposing factors
- transmission: endogenous; exogenous - predisposing factors: compromise in the integrity of skin or mucous membranes; impairment in some other host defense; presence of a foreign body - e.g. catheter, suture, prosthesis
Staphylococcus habitat
- worldwide in distribution - occur as commensals/normal flora: skin; mucous membranes; upper respiratory (nares) and lower urogenital tract; transient flora of the GI tract - some are opportunistic pathogens causing pyogenic infections - primary or secondary infections
Staphylococcus exfoliative toxin pathogenic effect
causes blistering, responsible for desquamation
Staphylococcus class
Bacili
Only coagulase-positive staphylococci are pathogenic
False
Staphylococci are catalase-negative
False
Staphylococcus aureus and Staphylococcus pseudintermedius are non-hemolytic
False
Staphylococcus aureus is responsible for greasy pig disease/exudative epidermitis
False
Staphylococcus phylum
Firmicutes
Exudative epidermitis / greasy pig disease aetiology
S. hyicus - causes 'greasy pig disease' - worldwide in distribution - occurs in sucklers and weaned pigs up to 3 months of age
Pyoderma in dogs caused by
S. pseudintermedius
Staphylococcus order
Lactobacillales
S. aureus in horses causes
Scirrhous cord (botryomycosis of the spermatic cord)
S. pseudintermedius in dogs causes
Pyoderma, endometritis, cystitis, otitis externa and other suppurative conditions
Tick pyemia in lambs: aetiological agent:
S. aureus - common in UK and Ireland - introduced into the blood stream through minor trauma and tick bites
Bovine staphylococcal mastitis aetiological agent
S. aureus (mainly) - endogenous/contagious mastitis - adapted to the bovine udder colonizing the teat and teat canal
Botryomycosis in horses and sows aetiology
S. aureus (mainly) causing chronic, suppurative, granulomatous condition
Staphylococci in poultry - Bumblefoot aetiology
S. aureus (mainly) causing pododermatitis/dermatitis, osteomyelitis, arthritis, bacteria and septicemia (rarely)
(PAMP) Pathogen-Associated Molecular Pattern
Staphage Lysate (SPL) administered -> Peptidoglycan (PGN) and LP (Lipoprotein) released into immune system -> T helper cells activated -> Cytokines released -> Phagocytes activated -> Staph ingested and lysed by phagocytes -> PGN and LP of lysed bacteria released into immune system -> LP and PGN released into immune system...
Staphylococcus family
Staphylococcaceae
S. aureus in dogs, cats causes
Suppurative conditions like those caused by S. pseudintermedius
Staphylococcus hyicus is non-hemolytic
True
Staphylococcus catalase pathogenic effect
breaks down hydrogen peroxide
Staphylococcus toxic shock syndrome toxin pathogenic effect
a superantigen in humans
Complete haemolysis =
alpha-haemolysin
Staphylococcus capsule pathogenic effect
anti-phagocytic
Staphylococcal infections in dogs and cats: treatment
appropriate antibiotics after sensitivity testing
Tick pyemia in lambs clinical signs
arthritis, ill-thrift, posterior paresis and severe cases septicemia, multi-organ abscesses and death
Staphylococcal infections in dogs and cats: control
aseptic surgical techniques; sanitization of clinics/hospitals
Incomplete haemolysis =
beta-haemolysin
Staphylococcus protein A pathogenic affect
binds IgG in a non-functional orientation to avoid phagocytosis
Staphylococcus adhesins pathogenic effect
binds to host cells, initation of the formation of biofilms
Tick pyemia in lambs: transmission: Ixodes ricinus
bite permits entry of S. aureus + Anaplasma phagocytophilum causing tick fever leading to immune suppression & predisposing to infections
Staphylococcus hyaluronidase pathogenic effect
breaks down connective tissue
Bovine staphylococcal mastitis pathogenesis: infection spreads by milkers, machines, cloths ->
colonization of the apex of the teat, forms microcolonies + minor teat lesions enhance colonization -> enter teat canals, multiply in milk (poor milking machines facilitate entry)
Staphylococcal infections in dogs and cats: diagnosis
culture and microscopy from clinical swabs
Staphylococcus hemolysins pathogenic effect
destroy red blood cells by lysis; alpha-hemolysin/alpha-toxin; Beta-hemolysin/Beta-toxin
Staphylococcus DNase pathogenic effect
digests DNA
Staphylococcus staphylokinase pathogenic effect
dissolves clots
S. pseudintermedius isolated mainly from
dogs and cats
S. delphini isolated from
dolphins, minks, ferrets and badgers
Exudative epidermitis / greasy pig disease MAJOR virulence factor
exfoliative toxin
Staphylococcus enterotoxins pathogenic effect
food poisoning in humans
Staphylococcus =
genus
S. caprae
goats/skin
Summary: antimicrobial sensitivity testing is important due to
high occurrence of resistance
S. equorum
horses/skin
Summary: Both coagulase-positive and coagulase-negative staphylococcus can cause
infections
Some Enterococci are of emerging importance because of
innate resistance to most common antimicrobial drugs
Staphylococcus leukocidin pathogenic effect
kills polymorphonuclear leukocytes
S. aureus in cattle causes
mastitis
Botryomycosis in sows
occurs in mammary tissues
S. schleiferi subsp. coagulans in dogs causes
otitis externa
Staphylococcal infections in dogs and cats: S. schleiferi subsp. coagulans causes
otitis externa in dogs
S. intermedius isolated mainly from
pigeons, dogs, minks, horses
Staphylococcus coagulase pathogenic effect
promotes clotting; may lead to walling off the infection site
Staphylococcus elastase pathogenic effect
protease that breaks down elastin
S. pseudintermedius in cats causes
pyogenic conditions
S. aureus and S. pseudintermedius produce double hemolysis on
sheep blood agar
Staphylococcal infections in dogs and cats: S. aureus occasionally causes
suppurative conditions
Summary: Coagulase activity is only one of many
virulence factors