Nosocomial Infections

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Nosocomial Infections

• John George

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• Applied to infections neither present nor in
  incubation at the time of admission
• Become manifest after 48 hrs
• Routes Direct contact
• Droplet infection
• Air borne particles
• Hospital procedures

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• Exogenous source being part of hospital
  ecosystem
• Iatrogenic induced by diagnostic or therapeutic
  intervention
• Oppurtunistic in immunosuppressed

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Factors

• Impaired defense
• Environment heavily laden with pathogens
• Invasive procedures diagnostic or therapeutic
  done in hospitals
• Routine use of anti-microbial agents in hospitals
  creates selection pressure for the emergence of
  resistant strains
• Medical staff move from patient to patient,
  providing a way for pathogens to spread.

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Microbiology

• Staphylococcus aureus Phage type 80/81 hospital
  staphylococci
• MRSAVancomycin,Teicoplanin, Mupirocin
• Staphylococcus epidermidiscoagulase ve,present
  on skin
• Nafcillin vancomycin

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• Streptococcus pyogenes susceptible to
  antibiotics.Due to asymptomatic carriers
• EnterococciVancomycin resistant enterococci
  (VRE)present on intact skin
• ciprorifgenta

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• Gram negative bacilli E.coli , Klebsiella ,
  Enterobacter , Proteus , Serratia
• Most important group of hospital pathogens
  Dissemination of R factors conferring multiple
  drug resistance
• 3rd ceph,aminoglycosides

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• Pseudomonas aeruginosa
• Intrinsic resistance to antibiotics
• Ability to survive at low temperatures and in
  disinfectants
• Ceftazidine,Ticarcillin
• Piperacillin

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• Tetanus spores
• Contaminate cotton , sutures , plaster of
  Paris

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• Legionella
• Contamination of potable water
• Azithromycin,Erythromycin

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Viruses

• HIV , Hepatitis B , C blood products
• Chicken pox , viral diarrhoea , CMV , Herpes ,
  Influenza , Enterovirus

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Fungi

• Aspergillus Present on dusty surfaces
• CandidaMouth,vagina
• Floconazole,Ampho B
• Mucor,Fusarium

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Protozoa

• Entamoeba histolytica , Plasmodium , Pneumocystis
  Carinii , Toxoplasma gondii

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Types

• Surgical site / wound infection
• UTI
• Respiratory infection
• Bacteremia
• Gastrointestinal tract infection

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UTI

• Most common type (34)
• GNB,S.aureus,S.epidermidis,E.faecalis Pseudomonas
• RoutesIntraluminal or periurethral
• Clinical featuresfever,dysurea
• frequency,pyurea,suprapubic pain,flank pain

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• Risk factors catheterization(10-12) Female
  gender,lack of antibiotic therapy,Diabetes
  mellitus,improper catheter care,Uremia,colonizatio
  n of the drainage bag

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Diagnosis

• specimens should be taken from catheterised
  patients when patient is febrile
• Specimens should be taken from the catheter and
  not from the bag
• gt100/ml of urine from catheter
• Culture and sensitivity

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Management

• Asymptomatic catheter-associated bacteriuria
  should not be treated.
• Remove or change the catheter,insert the new
  catheter under prudent antibiotic cover.
• Once culture results and sensitivities are known,
  antibiotic therapy can be amended if necessary

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Empirical Rx

• Duration of therapy is mainly guided by clinical
  response

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Prevention

• For lt 2wks
• Sterile closed collecting system
• Aseptic technique during insertion
• Short course of systemic Abs
• Topical periurethral Abs

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Respiratory infection

• 13 of nosocomial infections,mortality 30-50
• Pseudomonas aeuriginosa,GNB(50)
  Staph(10),Acinetobacter,Legionella,RSV
• Clinical features cough,fever,sputum p-roduction

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Risk factors

• intubated patients
• tracheostomy
• unconscious
• elderly patients
• chronic lung disease
• taking H2 blockers
• immunosuppression

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Diagnosis

• Leukocytosis,infiltrate on CXR
• In ICU patients signs are subtle due to fluid
  overload,CHF,ARDS
• Serial Gm stains of sputumPMNs

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Rx
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• Control Hand washing
• Decontamination of respirator
• equipment
• Barrier isolation
  materials,negative pressu-
• re rooms
• H2 blockers and antacids should
  not be
• used
• Minimize aspiration prone
  positioning
• Chemoprophylaxis

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Surgical site infection

• 19 of nosocomial infections
• Risk factors presence of drain
• long preoperative stay
• preoperative shaving gt
• 24hrs
  
• long duration of
• surgery
• health of patient
• tissue anoxia

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• CN staph , Staph Aureus commonest (3-7days)
• Strep pyogenes , clostridia 24-48 hrs
• GNB , Anaerobes 7 days

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• Examine wound for tenderness , induration
  fluctuation , discharge ,dehiscence of sutures
• Perioperative antibiotic prophylaxis , cleansing
  the skin with a disinfectant decreases wound
  infection

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Bacteremia

• Primary bacteremia Isolation of a recognized
  pathogen from blood without an infection at
  another site
• 14 of nosocomial infections
• Gm-ve bacilli, Staph aureus , coagulase ve staph
  , Candida , Enterococci
• Clinical features Fever , cutaneous involvement
  (erythema , induration , tenderness)
  ,hyperventilation , disorien-
• tation , DIC ,ARDS ,oligurea

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• Risk factors
• Duration longer than 72 hours
• Cut down placement
• Lower extremity site
• Poor hand washing

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Diagnosis

• Blood culture2 samples(10ml) from diff sites
• Line is removed , tip sent for quantitative
  culture (gt15 colonies)

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• Control moving of peripheral catheters to a new
  site at intervals , removal of idle catheters ,
  use of catheters impregnated with antinfective
  agents(sil sulfadiazine/
• Chlorhexidine
• IV catheters should be observed for signs and
  symptoms of infection

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Rx

• Remove source of infection
• Empirical therapy against both GP and GN bacteria
• Nafcillin gentamicin
  
• Haemodynamic , respiratory , metabolic support

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Prevention

• Observance of aseptic technique
• Frequent hand washing especially between patients
  , proper use of gloves , masks , face shields
  etc.
• Careful handling, cleaning, and disinfection of
  fomites

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• Where possible use of single-use disposable items
• Patient isolation
• Education of visitors - to avoid certain types of
  touching, wash hands, etc.
• Avoidance of medical procedures that can lead to
  high probability of nosocomial infection
• Various institutional methods such as air
  filtration within the hospital

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• Sterilization of equipment
• Re-usable devices should be
• autoclaved and single use
• devices should be discarded

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• Environmental surfaces, beds, bedrails, bedside
  equipment should be cleaned and disinfected
  regularly
• Care while using broad-spectrum antibiotics .

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Barrier nursing

• Barrier nursing is the use of infection control
  practices aimed at controlling the spread of, and
  destroying, pathogenic organisms
• Anything that comes into direct contact with the
  patient is considered infective and must be
  sterilised before being returned to general use

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• Reverse barrier nursing For those people who
  are most at risk of acquiring infections while in
  hospital.eg organ transplant recipients on
  immunosuppressive therapy

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