Bacterial Skin Infections_Course VIII.ppt

7/25/2019 Bacterial Skin Infections_Course VIII.ppt

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Bacterial SkinBacterial SkinInfectionsInfections

ProfessorSudheer Kher


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Learning Objectives

Enumerate the microbes causing skininfections.

Describe thecharacteristic clinical manifestationsmethods of laboratory diagnosis

principles of managementmethods of prevention of each of theinfections listed.


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Bacterial

Infection of SkinThe SkinDefinition

Skin is largest organ of body. Maintainshomeostasis, protects underlying tissues andorgans, protects body from mechanical injury,damaging substances, and ultraviolet rays ofsun.


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Recurrent skin

infectionsRecurrent skin infections should raisesuspicion of coloni ation

Staphylococcal nasal carriageResistant strains of bacteria !eg, methicillin"resistant Staphylococcus aureus #MRS$%&,'ancer

(oorly controlled diabetes)ther reasons for immunocompromise !eg, *+ ,hepatitis, advanced age, congenital susceptibility&.


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Pyoderma(yoderma is a group name for pyococcal dermatoses-hich are generally purulent. +n tropical countries,pyoderma is a common problem, particularly in thesummer and the monsoon.

The t-o important pyogenic organisms are theStaphylococcus aureus and the Streptococcus pyogenes.

ollicular infections are mainly due to staphylococci/-hile erysipelas and cellulitis are caused by streptococci.

0esides these, other organisms -hich occasionally comeacross in pyodermas are (roteus, (seudomonas and'oliform bacilli.


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Skin Infections

Infection Site Causal Organism

Boil Hair follicle Staphylococcus aureus

Carbuncle Multiple Hair follicles Staphylococcus aureus

Stye Hair follicle of eye lash Staphylococcus aureus

Sycosis barbae Shaving area Staphylococcus aureus

Pemphigus neonatorum Infants skin Staphylococcus aureus

To ic epi!ermalnecrolysis

Infants skin Staphylococcus aureus

Pemphigus neonatorum Infants skin Staphylococcus aureusTo ic epi!ermalnecrolysis

Infants skin Staphylococcus aureus

"rysipelas #ace$ sometimes limbs Streptococcus pyogenes

%cne vulgaris #ace & Back Propionibacterium acnes


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S. aureus produces

skin infection+. Direct infection of skin and adjacent tissuesa. +mpetigob. Ecthyma

c. olliculitisd. urunculosise. 'arbunclef. Sycosis barbae

++. 'utaneous disease due to effect of bacterialto1ina. Staphylococcal scalded skin syndrome

b. To1ic shock syndrome


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!emolyticstreptococcus produces

skin infection+. Direct infection of skin or subcutaneousa. +mpetigo !non bullous&b. Ecthymac. Erysipelasd. 'ellulitise. 2ecroti ing fascitis

++. Secondary infectionEc ema infection


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"olliculitisFolliculitis is a bacterial infection of hairfollicles. #olliculitis is usually cause! byStaphylococcus aureus but occasionallyPseu!omonas aeruginosa 'hot(tubfolliculitis) or other organisms* Hot(tub

folliculitis occurs because of ina!e+uatetreatment of ,ater ,ith chlorine orbromine*


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#olliculitis manifests as superficial pustules orinflammatory no!ules surroun!ing hair follicles*


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"uruncles and

#arbunclesFuruncles are skin abscesses caused bystaphylococcal infection, which involve a

hair follicle and surrounding tissue.Carbuncles are clusters of furunclesconnected subcutaneously, causing

deeper suppuration and scarring. Theyare smaller and more superficial thansubcutaneous abscesses


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#uruncles 'boils) are ten!er no!ules or pustules cause!

by staphylococcal infection* Carbuncles are clusters offuruncles that are subcutaneousl connecte!*


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$reatment of

folliculitisBecause most folliculitis is cause! by S* aureus$ clin!amycin -.lotion or gel may be applie! topically bi! for / to -0 !ays*%lternatively$ ben1oyl pero i!e 2. ,ash may be use! ,hensho,ering for 2 to / !ays* " tensive cutaneous involvement may,arrant systemic therapy 'eg$ cephale in 320 to 200 mg po ti! to +i!for -0 !ays)*

If these measures !o not result in a cure$ or folliculitis recurs$pustules are 4ram staine! an! culture! to rule out gram(negative ormethicillin(resistant S* aureus 'M5S%) etiology$ an! nares areculture! to rule out nasal staphylococcal carriage* Potassiumhy!ro i!e ,et mount shoul! be !one on a plucke! hair to rule outfungal folliculitis*

Treatment for M5S% usually re+uires t,o oral antibiotics$ an! thechoice of therapeutic !rugs shoul! be base! on culture an!sensitivity reports*

Hot(tub folliculitis usually resolves ,ithout treatment* Ho,ever$a!e+uate chlorination of the hot tub is necessary to preventrecurrences an! to protect others from infection*


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%idradenitis suppurativa

Hidradenitis suppurativa is a chronic,scarring inflammation of apocrine

glands of the axillae, groin, and aroundthe nipples and anus.


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#ellulitisCellulitis is acute bacterial infection ofthe skin and subcutaneous tissue most

often caused by streptococci orstaphylococci.


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$reatment of

cellulitisTreatment is ,ith antibiotics* #or most patients$ empirictreatment effective against both group % streptococci an! S*aureus is use!*

Oral therapy is usually a!e+uate ,ith !iclo acillin 320 mg orcephale in 200 mg po +i! for mil! infections* 6evoflo acin 200mg po once7!ay or mo iflo acin800 mg po once7!ay ,orks ,ell for patients ,ho are unlikely toa!here to multiple !aily !osing sche!ules*

#or more serious infections$ o acillin or nafcillin - g is given I9+ : h*

Immobili1ation an! elevation of the affecte! area help re!ucee!ema; cool$ ,et !ressings relieve local !iscomfort*


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#utaneous &bscess

cutaneous abscess is a locali!edcollection of pus in the skin and may

occur on any skin surface.


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'rysipelasErysipelas is a type of superficial cellulitis -ith dermallymphatic involvement.Erysipelas is characteri ed clinically by shiny, raised,indurated, and tender pla3ue"like lesions -ith distinct

margins. Erysipelas is most often caused by group $ !or rarelygroup ' or 4& 5"hemolytic streptococci and occursmost fre3uently on the legs and face.)ther causes " Staphylococcus aureus !including

methicillin"resistant S. aureus #MRS$%&, 6lebsiellapneumoniae, *aemophilus influen ae, Escherichiacoli.+t is commonly accompanied by high fever, chills, andmalaise. Erysipelas may be recurrent and may resultin chronic lymphedema.


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"rysipelas is characteri1e! by shiny$ raise!$ in!urate!$an! ten!er pla+ue(like lesions ,ith !istinct margins* It ismost often cause! by


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'ryt!rasmaErythrasma is an intertriginous infectionwith Corynebacterium minutissimum *Most common among patients withdiabetes and among people living in thetropics.


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Impetigo and

'ct!yma"mpetigo is a superficial skin infectionwith crusting or bullae caused by

streptococci, staphylococci, or both .#cthyma is an ulcerative form ofimpetigo.

I ti 'B ll )i ( ll )


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=on(bullous impetigo is a

superficial skin infection thatmanifests as clusters ofvesicles or pustules thatrupture an! !evelop a honey(colore! crust*

Bullous impetigo is a superficialskin infection that manifests asclusters of vesicles or pustules thatenlarge rapi!ly to form bullae* Thebullae burst an! e pose largerbases$ ,hich become covere! ,ithhoney(colore! varnish or crust*

Impetigo 'Bullous)Impetigo '=on(Bullous)


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Ecthyma gangrenosum is abacterial skin infection !caused

by $seudomonas aeruginosa &that usually occurs in people-ith a compromised immunesystem.

Ecthyma is a skin infectionsimilar to impetigo, but more

deeply invasive. 7sually causedby a streptococcus infection ,ecthyma goes through the outerlayer !epidermis& to the deeperlayer !dermis& of skin, possiblycausing scars.


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(ecroti)ing Subcutaneous Infection *(ecroti)ing "asciitis+

Typically caused by a mixture of aerobic and anaerobicorganisms that cause necrosis of subcutaneous tissue, usuallyincluding the fascia.

This infection most commonly affects the extremities and perineum. Affected tissues become red, hot, and swollen,resembling severe cellulitis.

Without timely treatment, the area becomes gangrenous. Patientsare acutely ill. Diagnosis is by history and examination and issupported by evidence of overwhelming infection.

Treatment involves antibiotics and surgical debridement.Prognosis is poor without early, aggressive treatment.


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2ecrotising fasciitis


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$reatment

8.Surgical debridement9. $ntibiotics:. $mputation if necessary


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acterial Infection

of SkinLab. ,iagnosis

Specimen collection.1. Skin biopsy2. Skin swab3. Pus swab

4. Nasal / skin swab


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Lab. ,iagnosisSuspecte! organismsImpetigo> 4roup $ Streptococcus, Staphylococcus

aureus#olliculitis> Staphylococcus aureus, $seudomonas

aeruginosa

#uruncles> Staphylococcus aureusCarbuncles> Staphylococcus aureusCellulitis> 4roup $ Streptococcus, Staphylococcus

aureus, Hemophilus influen!ae"rysipelas> %roup Streptococcus=ecroti1ing fasciitis : %roup Streptococcus,

Clostridium perfringens andother species, &acteroides fragilis,the anaerobes, #nterobacteriaceae,$seudomonas aeruginosa


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Principles of t!erapy ofpyoderma

4ood personal hygieneManagement of predisposing factors

;ocal $ttend to traumas, (ressure, S-eating, 0ites Treat pre"e1isting dermatosis +nvestigate carrier sites< 2ose, $1illa, (erineum

SystemicTreatment of disease like DM2utritional deficiency+mmunodeficiency


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Principles of t!erapy ofpyoderma

;ocal therapy'leaning -ith soap"-ater and -eak

6M2=> solution

Removal of crusts -ith 6M2=> solution

$pplication of antibacterial cream

Systemic therapy

$ntibiotics


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Recurrent stap!ylococcal

infection(ersistent nasal carriage

$bnormal neutrophilic chemota1is

Deficient intracellular killing

+mmunodeficient status

D.M.


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&ntibiotic ResistanceProfiles of -RS&

8== 0"lactam antibiotics> resistant to clindamycin and erythromycin

F resistant to ciproflo1acinC@ resistant to trimethoprimsulfametho1a ole:: resistant to tetracycline

: resistant to rifampin: resistant to fusidic acid9 resistant to mupirocin


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Bacterial Skin Infections_Course VIII.ppt