General Principle of Infection

WHO states : 

Infection prevention and control (IPC) is a practical, evidence-based approach to preventing patients and health workers from being harmed by avoidable infections. Effective IPC requires constant action at all levels of the health system, including policymakers, facility managers, health workers, and those who access health services. IPC is unique in the field of patient safety and quality of care, as it is universally relevant to every health worker and patient, in every health care interaction. Defective IPC causes harm and can kill. Without effective IPC it is impossible to achieve quality health care delivery.

Infection prevention and control affects all aspects of health care, including hand hygiene, surgical site infections, injection safety, antimicrobial resistance, and how hospitals operate during and outside of emergencies. Programs to support IPC are particularly important in low- and middle-income countries, where health care delivery and medical hygiene standards may be negatively affected by secondary infections.

https://www.who.int/health-topics/infection-prevention-and-control#tab=tab_1

General Principles of Infection Control

Bone and joint infections pose a formidable challenge to the orthopedic surgeon.

Surgical site infection rate= 2.8% (U.S. Centers for Disease Control and Prevention (CDC))

Osteomyelitis occurs when an adequate number of sufficiently virulent organisms overcomes the host’s natural defenses

Local skeletal factors also play a role in the development of infection

Unique characteristics of bone infection

   The mere presence of bacteria in bone whether from bacteremia or from direct inoculation is insufficient to produce osteomyelitis. Illness, malnutrition, and inadequacy of the immune system also can contribute to bone and joint infections.  For example, the relative absence of phagocytic cells in the metaphyses of bones in children may explain why acute hematogenous osteomyelitis is more common in this location.

Orthopedics surgeons should evaluate the risk of infection

Patient-Dependent Factors

Nutritional Factors

Why?

Basal energy requirement increases by 30 – 55% in case of infection and trauma

1ᵒ F fever increases Body metabolic rate by 13%

What Determines?

Anthropometric measurements

Height

Weight

Triceps skin fold thickness

Arm muscle circumference

Serum protein and cell types(lymphocytes)

Recommendations for nutritional support:

 Recent weight losses   > 10 lb(4.5 kg),

 Serum albumin levels   < 3.4 g/dL,

 Lymphocyte counts of   < 1500 cells/mm3

With the use of serum albumin and transferrin levels are available

   [(1.2 × serum albumin) + (0.013 × serum transferrin)] − 6.43

If the sum is 0 or a negative number, the patient is nutritionally depleted and is at high risk for sepsis.

IMMUNOLOGICAL STATUS

 Body’s main defense mechanisms

1. Neutrophil response

2. Humoral immunity

3. Cell-mediated immunity and

4. Reticuloendothelial cells

Neutrophils abnormalities

 Neutrophil count decreases < 55/ mm3

  (Staphylococcus aureus, gram-negative bacilli, Aspergillus organisms, and Candida)

Causes:

1. Diabetes

2. Alcoholism

3. Hematological Malignancy

4. Cytotoxic therapy

Humoral Immunity

1. Immunoglobulins

2. Complement factors

Causes:

Splenectomy (hypogammaglobinemia)

  Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria organisms

Complement cascade deficiency:

 S. aureus and gram-negative bacillus infections are common

Cell-Mediated Immunity

Causes:

1.Corticosteroid therapy

2. Malnutrition

3. Lymphoma

4. Systemic lupus erythematosus

5. Immunodeficiency in elderly patients

6. Autoimmune deficiency syndrome

●

Fungal, mycobacterial, herpesvirus ,Pneumocystis jiroveci.

Vaccinations also play a role in the host response

Hepatitis B vaccine

H. influenzae type B vaccine

Other Factors:

Smoking Cessation 4-6 weeks preoperatively

Maintain dental hygiene

Complete any dental treatment before elective surgery

Shower on the day of surgery

SURGEON-DEPENDENT FACTORS

 SKIN PREPARATION

 The skin and hair can be sterilized with alcohol, iodine, hexachlorophene, or chlorhexidine

Impossible to sterilize the hair follicles and sebaceous glands where bacteria normally reside and reproduce.

Hair removal at the operative site is not recommended unless done in the operating room

HAND WASHING

 The most important procedure

Hand scrubbing for 2 minutes is as effective as traditional hand scrubbing for 5 minutes.

Parienti et al.

       Hand scrubbing with an aqueous alcohol solution that is preceded by a 1-minute nonantiseptic hand.

Gloves

U.S. Food and Drug Administration accepts a 2.5% failure rate

Gloves perforation = 48%

Approx. 40 min into the procedure

83% time surgeons in unaware

Index finger or thumb of the non-dominant hand

Preventions??

 Double gloving reduces the exposure rate by as  much as 87%

Biogel indicator gloves increase awareness of perforation

 At a minimum, surgical gloves should be changed every 2 hours.

Drapes

Use of iodine-impregnated incise drapes benefits.

OPERATING ROOM ENVIRONMENT

Airborne bacteria

1 individual sheds =  5,000 to 55,000 particles/min

Conventional operating room air =10 to 15 bacteria per cubic foot   250,000 particles per cubic foot.

Prevention??

1. laminar-airflow systems

2. personnel-isolator system

●

Contaminations reduce the 80 %

Other methods :

Ultraviolet Light

 PROPHYLACTIC ANTIBIOTIC THERAPY

Given 30min-1 hr before incision and continued for 24 hour postoperatively

Administer minimum 5 minutes before tourniquet inflation

If cementation is required= should be antibiotics impregnated

A maximal dose of antibiotic should be given initially.

repeated every 4 hours intraoperatively/the blood loss exceeds 1000 to 1500 mL.

Extending antibiotics >24 hr

 thrombophlebitis

allergic reactions

Superinfections

drug fever

 Evidence now shows that 24 hours of antibiotic administration is just as beneficial as 48 to 72 hours.

Topical Antibiotics

1. A wide spectrum of antibacterial activity,

2. The ability  to remain in contact with normal tissues without causing  significant local irritation,

3. Low systemic absorption  and toxicity,

4. Low allergic

5. Minimal potential to induce bacterial resistance, and

6. Availability in a topical preparation that can be easily suspended in a physiological solution

Blood Transfusion

Optimize pre-operative hemoglobin

In case of anticipated blood loss—transfusion should be more than 48 hr. before surgery

If possible transfusion should be avoided intraoperatively.

Take Home Messages

Bone has unique physiological and anatomical characteristics hence its infection is always challenging

An orthopedic surgeon should evaluate the risk of infection in each patient by considering patient-dependent and surgeon-dependent factors

 Simply stated, it is much easier to prevent an infection than it is to treat it.

Thankyou….