[MICRO 20] LEC 15 - Healthcare-associated Infections

Ignaz Semmelweis

Noticed that babies born in the maternity ward handled by medical students/doctors were most likely to get a fever and die compared to those who were in the ward with midwives.

Florence Nightingale

Implemented handwashing and hygiene practices in the war hospital.
Achieved reduction in infections.

NOSOCOMIAL INFECTIONS

= infections absent at the time of admission and was acquired in the healthcare setting
= Associated with prolonged stay in the hospital or inadequate hygiene practices of personnel

Cross-infection

Indirect spread of pathogens from one patient to another on inadequately cleaned hands of hospital personnel

Autoinoculation

Aspiration of oropharyngeal flora into the lungs along the endotracheal tube

Urinary tract infections

From pathogens that spread up the periurethral space from the patient’s perineum or gastrointestinal tract

Intraluminal contamination

contamination due to cross infection by caregivers who are irrigating catheters or emptying drainage bags

pyuria

pus in urine

catheter-associated UTI or CAUTI

Non-localizing systemic symptoms in a patient with urinary catheter
- Fever
- Peripheral leukocytosis
- Altered mental status

catheter-associated asymptomatic bacteriuria

Positive urine culture in the absence of urinary symptoms and systemic symptoms related to the urinary tract in a patient with urinary catheter

D

Some recommended antibiotics for uncomplicated UTI are as follows EXCEPT:

A. Nitrofurantoin
B. Fluoroquinolones
C. Fosfomycin
D. Metronidazole

TRUE

[TRUE OR FALSE] Place bladder catheters only when absolutely needed (eg. to relieve obstruction), not solely for the providers’ convenience

Nosocomial Pneumonia

- Accounts for 10-15% of nosocomial infections
- associated with more deaths than are infections at any other body site

Oropharyngeal colonization

- Elimination of normal flora from antibiotic treatment
- Aspiration around the time of intubation
- Gastroesophageal reflux
- Bacterial overgrowth in the stomach

False; it belongs to non-MDR pathogens

[TRUE OR FALSE] Klebsiella pneumoniae belongs to MDR pathogens

True

[TRUE OR FALSE] Legionella pneumoniophila belongs to MDR pathogens

False; it belongs to non-MDR pathogens

[TRUE OR FALSE] Serratia marcescens belongs to MDR pathogens

Streptococcus pneumoniae

- usually seen in community-acquired pneumonia but can also be observed in ventilator-acquired pneumonia
- Gram-positive, lancet-shaped diplococci
- Catalase negative
- Bile and optochin sensitive
- Positive Quelling reaction

Positive Quelling reaction

Capsular swelling when mixed with antiserum (antibodies against polysaccharide capsule) and methylene blue on a glass slide

Septic shock

splenectomy predisposes to sepsis from encapsulated bacteria

PSEUDOMONAS AERUGINOSA

- Widely distributed in nature and is commonly present in moist environments in hospitals
- Known to cause disease in people with altered and decreased host defenses (neutropenia, chemotherapy, and burn wounds)
- Motile, rod-shaped, Gram-negative; occurs as single bacteria, in pairs, or occasionally in short chains
- In culture, it produces a sweet or grape-like or taco-like odor

Burn wounds

First barrier against infection (skin) is compromised

Pyocyanin

nonfluorescent bluish pigment

Pyoverdine

gives greenish color to the agar (Mueller-Hinton Agar) when combined with pyocyanin

Pyorubin

dark red pigment

Pyomelanin

black pigment

Exotoxin A

causes tissue necrosis by blocking protein synthesis (blocks elongation factor 2)

True

[TRUE OR FALSE] P. aeruginosa is pathogenic only when introduced into areas devoid of normal defenses, such as mucous membranes and skin disrupted by direct tissue damage

meningitis

this disease can occur when P. aeruginosa is introduced by lumbar puncture or neurosurgical procedures

Mild otitis externa

clinical findings of P. aeruginosa that is mostly found in swimmers

Ecthyma gangrenosum

hemorrhagic necrosis of the skin

Folliculitis

clinical findings of P. aeruginosa that is associated with poorly chlorinated hot tubs and swimming pools

False; P. aeruginosa can destroy beta-lactam antibiotics

[TRUE OR FALSE] Beta-lactamase can be used as a treatment for P. aeruginosa

Surgical wound infections

Caused by:
- Patient’s endogenous or hospital acquired and mucosal flora
- Airborne spread of skin squames that may shed to wound (from OR personnel)
- Rarely, airborne spread through droplet nuclei from an infected “disseminator” among the staff

False; should be administered 1 hour before surgery

[TRUE OR FALSE] Administering prophylactic antibiotics within 1 hour after surgery is a must to prevent surgical site infection

INTRAVASCULAR DEVICE-RELATED BACTEREMIA

Infection is derived from cutaneous microflora of the insertion site, with pathogens migrating extraluminal to the catheter tip

True

[TRUE OR FALSE] Diagnosis for intravascular device-related bacteremia include: Recovery of the same species of microorganisms from the peripheral blood cultures (2 sites) and from semi quantitative or quantitative cultures of the vascular catheter tip

True

[TRUE OR FALSE] a devoid of proper handwashing in a hospital setting can produce HAP or VAP

True

[TRUE OR FALSE] The care bundle approach to providing medical care forms part of a more general philosophical change in the way that medicine is practiced

True

[TRUE OR FALSE] The choice of inclusion in a care bundle is heavily based on expert opinion

False; Semmelweis' discovery was hardly accepted because it's merely seen as a simple cure an recommendations

[TRUE OR FALSE] Semmelweis' proposed a practical handwashing measures and his colleagues immediately accepted and practiced it

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