Question

Courses Name: INTRODUCTION TO HOSPITAL EPIDEMIOLOGY PHC 231

Discuss Central Line-Associated Bloodstream Infection (CLABI) "or" Ventilator-Associated Pneumonia (VAP) outbreak in long-term acute care hospital settings. Address the following in your report:

a)   Characterize the epidemiology and microbiology
b)   Describe the agent, and identify the host and the environment that is favorable
for the infection.
c)   Discuss how the infections spread and the types of prevention and
control measures
d)   Identify a population and develop a hypothesis about possible causes
in a testable format with standard statistical notation (the null and the alternative)
e)   Explain how you would choose controls to test this hypothesis?

Answer 1

Ventilator associated Pneumonia

Ventilator associated pneumonia is one of the most common hospital acquired infection in patients in intensive care units. It is associated with increased mortality, morbidity, length of hospital stays and increased cost of hospitalization. Ventilator associated pneumonia is a hospital acquired pneumonia that occurs at 48 hours or more after tracheal intubation with symptom onset 3 days or more after the hospital stay


a)  Characterize the epidemiology and microbiology

Incidence- There is wide variation in incidence of ventilator associated pneumonia in different settings and different countries. Global incidence varies from 8 to 28 percent.

Incidence increases with duration of mechanical ventilation - 3% /day for first 5days, 2%/day for 6-10days and 1%/day after 10 days.

Mortality rate is 27% &43%with antibiotic resistant organism according to critical care societies collaboratives (CCSCs)

Mortality rate in VAP caused by Pseudomonas or Acinetobacter is as high as 76 .

b)   Describe the agent, and identify the host and the environment that is favourable for the infection.

1. Agent- Early-onset VAP is mainly caused by community pathogens with a favourable pattern of antibiotic sensitivity, whereas late-onset VAP is often caused by multidrug-resistant pathogens.

The predominant etiologic agents responsible for early onset (within 4 days) are Staphylococcus aureus, streptococcus Pneumoniae. H. Influenza, Proteus and Klebsiella pneumoniae.

Organism responsible for late onset VAP(after 4 days) are mainly drug resistant Pseudomonas aeruginosa, Methicillin resistant staphylococcus aureus, actinobacteria, enterobacteria, vancomycin resistant enterococci.

2. Host factors- Factors that increases risk for ventilator associated pneumonaie are : age >70 years, underlying Lung Disease, viral Respiratory Tract Infections, severe associated Illnesses or co morbidities, depressed Mental Status, immunocompromising conditions, immobilisation that impede normal pulmonary toilet
3. Environment-intensive care setting, contaminated hands, contaminated equipments, indiscriminate use of antimicrobial agents

c)   Discuss how the infections spread and the types of prevention and
control measures

Spread of infection:

Bacteria enter the lower respiratory tract via following pathways: –

Aspiration of organisms from the oropharynx and GI tract (most common cause)- is primary route of entry of organisms in lower respiratory tract (LRT). Endotracheal tube keeps the vocal cords open-predispose to micro & macro aspiration of colonized bacteria from oropharynx to LRT. Another cause is Leakage of secretion containing bacteria around the ETT cuff.

Interrupted gastro-oesophageal sphincter due naso/ oro gastric tubes for feeding which keeps the gastro oesophageal sphincter open, or positioning of patient also lead to GI reflux and aspiration, increase oropharyngeal colonization and pathogenesis

Direct inoculation – Inhalation aerosols containing bacteria from other patients/ healthcare personnel’s, visitors, inadequate disinfection/sterilization of equipments, contaminated solutions/water for suctioning

Hematogenous spread – from intravenous catheter or other sites of infection in body

Prevention and control measures

1. Design of ICU -Adequate space, lighting, proper function of ventilatory system, facilities for hand washing, Isolation room.
2. Staffing- education, adequate number, quality, importance of personal cleanliness and attention to aseptic procedures.
3. Hand washing and Hand rubbing with alcohol-based solution.
4. Periodical bacterial monitoring and fumigation policy.
5. VAP BUNDLE – A group of interventions related to ventilator care when all are applied simultaneously there is enhanced reduction in incidence of ventilator associated pneumonia than each intervention applied separately. They are

• Elevation of head end of bed to at least 30 degrees. Supine position is an independent risk factor for many complications in hospitalized patients.
• Daily interruption of sedation, waking the patient unless contraindicated and assessment for readiness to wean to minimise duration of mechanical ventilation
• Through oral care and suctioning
• Peptic ulcer and deep vein thrombosis prophylaxis

6. Daily oral care - due to absence of mechanical chewing, dental plaque and saliva becomes reservoir for potential pathogens that can cause VAP. Intervention like

• Tooth brushing twice daily
• Rinsing of oral cavity with15 ml of alcohol free anti septic oral solution
• Routine suctioning to prevent accumulation of secretions

7. Nasogastric feeding- monitoring of gastric residue and avoid overfeeding, elevate head end of bed after feeding
8. Suction devices- Policies for use and storage of such suction devices and suction catheter

Change catheter

• Change suction catheter every day

• Rinse with sterile water or NS

• Allow to air dry Should be done using a 14 Fr sterile suction catheter to avoid trauma to mucosa

• apply suction intermittently

9. Changing patient position or turning laterally 2 hourly
10. Monitoring for signs of complications, prompt recording and reporting

d)   Identify a population and develop a hypothesis about possible causes
in a testable format with standard statistical notation (the null and the alternative)

Alternative hypothesis:

There is significant difference in incidence of ventilator associated pneumonia on 7^th day of ventilation among the patients receiving four hourly oral care versus those receiving twelve hourly oral care in intensive care units of selected hospital settings.

Null hypothesis:

There is no significant difference in incidence of ventilator associated pneumonia on 7^th day of ventilation among the patients receiving four hourly oral care versus those receiving twelve hourly oral care in intensive care units of selected hospital settings.

e)   Explain how you would choose controls to test this hypothesis?

1. The study excluded ICU patients whose hospital stay was shorter than 2 days and patients who showed symptoms of infection within 2 days of admission

Controls will be chosen on the basis of following criteria

• No prior co morbidities that can affect incidence of pneumonia
• Nearly similar age or a control for each individual in experimental group
• Ensuring similarity in length of hospital stay in patients in both experimental and control group
• Random allocation of subjects to experimental and control groups after establishing quota for different age groups and sex.

Answer 2

Hospital acquired infections (HAIs) is a major safety concern for both health care providers and the patients. Considering morbidity, mortality, increased length of stay and the cost, efforts should be made to make the hospitals as safe as possible by preventing such infections. These guidelines have been developed for health care personnel involved in patient care in wards and critical care areas and for persons responsible for surveillance and control of infections in hospital

The Centers for Disease Control and Prevention (CDC) defines health care-associated infections (HAIs) as infections acquired while in the health care setting (e.g., inpatient hospital admission, hemodialysis unit, or same-day surgery), with a lack of evidence that the infection was present or incubating at the time of entry into the health care setting. These definitions need to respond to a changing medical environment. Modern medical care has become more invasive and therefore associated with a greater risk of infectious complications. An aging population, the AIDS epidemic, the growth of chemotherapeutic options for cancer treatment, and a growing transplant population have expanded the population at an increased risk for infection as a consequence of interactions with the health care system. Both surgical care and medical care that are increasingly complex and invasive are being provided in non-acute-care settings, making the definition of a health care setting more problematic.

Risk factors commonly reported for hospital-acquired pneumonia often fall into one of the following cathegories: (1) factors that enhance colonization of the oropharinx or stomach; (2) conditions that favor aspiration into the respiratory tract; (3) prolonged ventilatory support; and (4) host factors, such as extremes of age and severe underlying conditions.

Infections can spread in many ways

• Physical contact. Infections, especially skin contagions, are spread by direct physical contact
• Droplet spreading. Colds, strep throat etc.
• Contaminated items
• Bowel movements. ...
• Exposure to blood.

Types of prevention and control measures include

• Hand hygiene
• Prevention of surgical site infections
• IPC to combat antimicrobial resistance
• Injection safety
• Burden of health care-associated infections
• Ebola response and recovery
• IPC country capacity-building
• Prevention of sepsis and catheter-associated bloodstream infections
• Prevention of catheter-associated urinary tract infections.

Infection control personnel play an important role in preventing patient and health care worker infections and preventing medical errors. An infection control practitioner (ICP) is typically assigned to perform ongoing surveillance of infections for specific wards, calculate infection rates and report these data to essential personnel, perform staff education and training, respond to and implement outbreak control measures, and consult on employee health issues. Clinical care staff and other health care workers are the frontline defense for applying daily infection control practices to prevent infections and transmission of organisms to other patients. Although training in preventing bloodborne pathogen exposures is required annually by the Occupational Safety and Health Administration, clinical nurses (registered nurses, licensed practical nurses, and certified nursing assistants) and other health care staff should receive additional infection control training and periodic evaluations of aseptic care as a planned patient safety activity

Any patient who is mechanically ventilated is at risk for VAP. The rate of contracting VAP has been described as 3 per cent per day during the first week of mechanical ventilation, 2 per cent per day during week 2 and 1 per cent per day in the ensuing weeks. The overall incidence of VAP ranges widely, from 5 to 67 per cent depending on the diagnostic criteria used. Multiple additional risk factors have been shown to increase the rates of VAP. These are easily divided into non-modifiable and modifiable categories. Non-modifiable risk factors include male gender, increased age (over 60 yr), history of chronic obstructive pulmonary disease, presence of a tracheostomy or cranial trauma, recent neurologic surgery, acute respiratory distress syndrome, multiorgan system failure, and coma. Potentially modifiable risk factors include supine positioning, gastric overdistension, colonization of ventilator circuits, low pressure in the ETT cuff and repeated patient transfers.

As discussed above, any intubated patient is at risk for development of VAP and the longer the duration of mechanical ventilation, the higher the risk. Thus, prevention of VAP must begin with avoiding or limiting time of mechanical ventilation whenever possible. Several strategies have been described to achieve this goal: non-invasive positive pressure ventilation (NPPV), sedation holidays, weaning trials, avoiding re-intubation, and early tracheostomy have all been studied as methods to decrease time of mechanical ventilation and therefore, decrease the risk of VAP

VAP continues to be a commonly encountered challenge amongst critically ill patients and carries significant burdens of morbidity, antibiotic utilization and cost. Studies on prevention strategies directed towards the pathophysiologic mechanisms of VAP have shown variable success. However, certain measures as described in this review have been shown to improve patient outcomes and, therefore, we recommend care providers consider a multidisciplinary strategy incorporating the following: NPPV when able; sedation and weaning protocols for those patients who do require mechanical ventilation; mechanical ventilation protocols including head of bed elevation and oral care; and removal of subglottic secretions. Future research that considers clinical outcomes as primary end points will hopefully result in more detailed prevention strategies.

Answer 3

1) ventilator associated pneumonia:-

VAP is a type of pneumonia that develops 48 hours after endotracheal intubation .it is a minor source of increased illness and death.

Symptoms-

* Fever or low body temperature

*Purulent sputum

*Hypoxemia

Causes-

*Previous aspiration event

*Prior antibiotic exposure

*Underlying heart or lung disease and trauma

Diagnosis:-

*Increased temperature

*Increase in WBC more than 12000 or less than 4000

*Purulent secretions

*Respiratory distress

*Chest X rays

*Positive cultures

a) epidemiology:-

8-28% if patients receiving mechanical ventilation are affected by VAP.

Mainly occurs more often in the first week of mechanical ventilation

In case of gender-men are fount to get more VAP while women more likely die after VAP.

Microbiology:-

Common causative pathogens are gram-negative bacteria such as pseudomonad aeruginosa ,Escherichia coli ,Klebsiella pneumoniae and acinetobacter species.

And gram positive bacteria such as staphylococcus aureus.

b)the agents causes VAP are the gram negative and gram positive bacteria that furnished above.pnemonia is a host response bacterial infection .

c) the resistant bacteria can spread from patient to individuals mostly when they to endotracheal suctioning or when comes in contact with sputum which has been collected in the respiratory tract. Proper use of PPE, sterile techniques and waste management can reduse the slreadspread

prevention and control measures:-

*Discontinue mechanical ventilation as soon as possible

*Restrict bacteria spread by proper hand washing, sterile techniques for invasive procedures.

*Isolation of patient with known resistant organisms

*Antiseptic mouth wash for mouth care

*Use of mask and gloves properly

*Proper waste disposal of infected individuals

Answer 4

A central line - associated blood stream infection (CLABI) is a serious infection that occurs when germs enter the blood stream through the central line. A central line is a catheter that doctors often place in the large vein in the neck, chest or groin to give medications or fluids or to collect blood for medical tests. An Intravenous catheter (also known as IVs) that are used frequently to give medicines or fluids into a vein near the skin surface usually on the arm or hand for short periods of time. But central lines are different from IVs because central lines access a major vein that is close to the heart and can remain in place for weeks or months more likely to cause serious infection.   

a) As a result of the central lines location, this type of catheter can occasionally allow pathogens to gain direct entry into the bloodstream. If this occurs because of the location, the patient becomes unwell or infected quickly. CLABIs lead to prolonged hospital stay and increased health care costs and mortality. An estimated 250,000 bloodstream infections occur annually and most are related to the presence of intravascular devices The main locations are Adult ICUs, Pediatric ICUs, Adult wards, Pediatric wards, oncology units and wards.

b) The main causative organisms are Gram-positive organisms (coagulase-negative staphylococci), staphylococcus aureus, enterococci are the most common.Pathogens associated with an increasing number of infections over the 6 years were Candida species in the ICUs and Enterobacteriaceae in oncology units. Host factors that increase the risk of CLABSIs are chronic illness (malignancy, hemodialysis, gastrointestinal tract disorders, pulmonary hypertension), immune compromised states (bone marrow transplant, end-stage renal disease,diabetus mellitus), malnutrition, prolonged hospitalization before line insertion, catheter type, catheter size, catheter site care, etc. The environment favourable for this infection includes contamination of  the inserton, the patient's skin flora, contamination of the components of IV sets, poor patient hygine, impaired skin integrity, prolonged durationof the catheter,etc.

c) Practices for antimicrobial prophylaxis and empiric antimicrobial therapy should be applied. Restricted to patients with limited vascular access or those who need central access for survival. Hygenic need to health care professional mainly for nursing staffs is needed.

d)The population most infected are the patients of ICUs, oncology units, Surgery units, prolonged hospitalized patients, chronic illness patients, etc

e) Hygenic education to both the healthcare professional and also the patient and their byestanders. Proper instructiions to be given by the healthcare professional to the patient to deal with the catheter while taking fluids. Proper cleaning the area of the catheter site and skin area.

Answer 5

Central line Assoicated blood stream infection:
1, CLABI is a important cause of mortality and morbidity among hospital settings. In ICUs hospitalized patient infections estimated 23,000 in 2009. it was 24, 179 nosocomial BSI from 49hospitals in the US in 1995 and 2002. patient with CLABI in CICU Venous line 86% and in femoral line 22% and jugular access 76.5%. Most common organism detected in blood culture is gram positive(64%) and gram negative (26%(bacilli. the gram-negative organisms in CLABI increased in the developing countries that include klebsilla, pseudomonas spp, e.coli, Acinetobacter spp, proteus spp and staphyloccous epidermidis. estimated 2,50,00 CLABI presented in the intravascular devices.
2, Host factors increase the risk with chronic disease like cancer, GI tract disorder, pulmonary hypertension, nemodialysis and with immunosuppraant patients, TPN infusion, blood transfusion, malnutrition, burns, older age, and long hospital stay, type of catheter used and catheter location. femoral line and internal jugular vein have the highest risk than subclavian vein. poor hygeine and preacutions, site care, poor skills about catheter insertion are the major cause for thris infection. pseudomonas and candida make severe illness and increase the virulence and increase resistance.
3, CLABIs occur when bacteria or germ enters the central line and into the bloodstream. proper hand hygiene, barrier precautions while inserting catheter using maks, cap and gloves, avoiding femoral vein for catheter insertion using chlorhexidine skin antiseptic for catheter dressing. Central site care and avoiding unnecessary catheters can prevent this infection. control measures include routine dressing changes every 2 days using chlorhexidine dressings. Avoiding short term non-funneled catheter, change tubing every 24hours if any blood transfusion and fat deposition occur. assess catheter site for any infection, educate health professionals for the proper procedure for insertion and maintenance, related policies and supplies.
4, CLABI made a substantial threat to hospitalized patients. Monthly data analysis for meta-analysis including elderly population and adults with 12 to 24 months follow-up analysis in ICUs followed by quality improvement, it provided intervention that reduced CLABI after beneficial results with using ITS study design provided effective sizes and confidence intervention. there is no much difference found between population group and baseline infection rates and with suboptimal rates for these studies. it shows a statistically AP value <05 with negative changes for infection rates.

Answer 6

#. Central line associated blood stream infection:

#. Etiology:

-Coagulase negative staph (gm +)

-Staph aureus

-Enterococcus (Gm +)

-Gram neg rods (E-coli, Klebsiella, psuedomonas)

-Candida

#. Epidemiology:

Infection rate in descending order

-Pulm. Artery catheter (3.7%)

-Arterial Catheters (1.7%)

-Central venous Catheter (1.6%)

-PICC line (1.1%)

-Peripheral IV (0.5%)

-Peripheral midline catheter (0.2%)

#. 3 ways for CVC to become infected:

1. Contiguous skin flora

2.Catheter hub contamination

3. Infection binding to catheter from a distant site

#. Risks:

-Prolonged hospitalization prior to Central cath (CVC) insertion

-Multiple CVC's

-Femoral or IJ insertion site

-Lots of bacteria at insertion site

-Multilumen CVC's

-Lack of maximal sterile barriers for CVC insertion

-CVC insertion in ICU or ED

-Sub clavian is the cleanest and most preferred site.

#. When should catheter be removed :-

Reasons to REMOVE:

-Severe sepsis (i.e. LOW BP)

-endocarditis or evidence of spread from catheter

-Suppurative thrombophlebitis (pus)

-Bacteremia lasting more than 72 hours after initial treatment

-If the infection is:

-Staph aureus

-Pseudomonas

-Fungi

-Mycobacteria

-More than 1 bacteria infection (polymicrobial)

#. CLABSI prevention :-

-Use a protocol

-Stay clean

-Remove CVC ASAP

-proper maintenance

-Avoid the danger zones (femoral or IJ)

-Maximal sterile barriers

Diagnosis:

-Confirmed by having the same bacteria found at the tip of the catheter and at another venipuncture site

-The bacteria from the catheter has a higher colony count and turns + 2 hrs faster

Answer 7

Central Line associated bloodstream infection is a serious infection that occurs when germs enter the bloodstream through The Central Line

Symptoms :

Fever

Chills

Red skin

Soreness around the neck

Epidemiology :

In recent prevalence and study 1 in 28 percentage of acute care patients having central Line associated bloodstream infection

Microbiology:

It is mainly caused by gram Negative organisms like pseudomonas, klebsiella, proteus, acinetobacter

Prevention and control measures

Hand hygiene

Apply appropriate skin antiseptic

Ensure that the skin has completely dried before inserting the central line

Use of barrier precautions like sterile gloves

Sterile gown

Cap

Mask

Large sterile drape

Don’t let any visitors to touch the catheter or tubing

The patient should avoid touching the tubing

Answer 8

Ventillator associated pneumonia is a intencive care unit acquired infection. It is seen when ventilation is given through endotracheal tube mechanically. It affects about 4.8%-7.5% patients intubated for longer than 24 hours and is associated with morbidity and mortality. VAP is associated with bacteria infection, the fungus and virus are rarely involved. VAP is caused by the pathogens including streptococcus pneumoniae, Haemophilus influanzae, staphylococcus aureus, klebseilla pneumonea, pseudomonas aeruginosa.

The most common host for VAP infection are the patient with pre existing pulmonary diseases, multiple organs system failure, coma, AIDS, head trauma and are ventillated for the same. Intubation and mechanical ventilation are the prerequisite for the development of infection.

VAP can occur by various routes like haematogenous spread from a distant focus of infection, contiguous spread, inhalation of infectious aerosol and aspiration. For the prevention of VAP infection, 3 factors associated with the infection has to be focused. That are the aspiration of secretions, the colonisation Of aero digestive tracts and the use of contaminated equipments. The CDC recommended to use non invasive positive pressure ventilation instead of intubation and try to minimise the time of ventilation. In ICU a every day practice of hand hygiene and maintaining patient oral hygiene can prevent the colonisation of bacteria.

Considering the cases of hospital, the VAP infection accounts for 13-18% of all hospital acquired infection. Tracheal intubation in the hospital contribute 3-21fold risk. Risk of infection increased as the time for mechanical ventilation increases. Highest risk is during the first 8-10 days of mechanical ventilation. The patients are selected and catagorised as modifiable and non modifiable patient on the basis of risk associated.

Answer 9

a.) CLABI occurs in 3% - 10% of catheterization, Mortality goes upto 25% as it originates from the I.V Catheter.

Microbiological aspect-

​​​​​​

Organism	Percentage Infection
Staphylococcus aureus	22.0
Coagulase-negative staphylococcus	37.0
Yeasts	9.3
Enteric Gram-negative bacilli	12.4
Enterococci and streptococci	4.9
Pseudomonas	5.5
Other	8.9

b.) Agent - Staphylococcus Aureus, Coagulase negative Staphylococcus,Yeast , Streptococci

Host- Chronic illness (malignancy, hemodialysis, gastrointestinal tract disorders), immune compromised states (bone marrow transplant, end-stage renal disease, diabetes mellitus), malnutrition, prolonged hospitalization before line insertion, catheter type, catheter size, catheter site care, etc.

Environment- Contamination of  the insertion, the patient's skin flora, contamination of the components of IV sets, poor patient hygiene, impaired skin integrity, prolonged duration of the catheter, etc.

c.) The spread of the Infection occurs directly from central Catheter line to Heart and then it Can reach to any organ as the Heart Pumps Blood to all the Organs of Body and it can cause bacteremia and sepsis.

Prevention and Control of this Bacteremia is by Prophylactic and Empericial Microbial Therapy and Removal Of Catheter if the Infection persists is the Best Way out For Treatment.

Answer 10

#. Central line associated blood stream infection:

#. Etiology:

-Coagulase negative staph (gm +)

-Staph aureus

-Enterococcus (Gm +)

-Gram neg rods (E-coli, Klebsiella, psuedomonas)

-Candida

#. Epidemiology:

Infection rate in descending order

-Pulm. Artery catheter (3.7%)

-Arterial Catheters (1.7%)

-Central venous Catheter (1.6%)

-PICC line (1.1%)

-Peripheral IV (0.5%)

-Peripheral midline catheter (0.2%)

#. 3 ways for CVC to become infected:

1. Contiguous skin flora

2.Catheter hub contamination

3. Infection binding to catheter from a distant site

#. Risks:

-Prolonged hospitalization prior to Central cath (CVC) insertion

-Multiple CVC's

-Femoral or IJ insertion site

-Lots of bacteria at insertion site

-Multilumen CVC's

-Lack of maximal sterile barriers for CVC insertion

-CVC insertion in ICU or ED

-Sub clavian is the cleanest and most preferred site.

#. When should catheter be removed :-

Reasons to REMOVE:

-Severe sepsis (i.e. LOW BP)

-endocarditis or evidence of spread from catheter

-Suppurative thrombophlebitis (pus)

-Bacteremia lasting more than 72 hours after initial treatment

-If the infection is:

-Staph aureus

-Pseudomonas

-Fungi

-Mycobacteria

-More than 1 bacteria infection (polymicrobial)

#. CLABSI prevention :-

-Use a protocol

-Stay clean

-Remove CVC ASAP

-proper maintenance

-Avoid the danger zones (femoral or IJ)

-Maximal sterile barriers

Diagnosis:

-Confirmed by having the same bacteria found at the tip of the catheter and at another venipuncture site

-The bacteria from the catheter has a higher colony count and turns + 2 hrs faster

Answer 11

Ventilator associated Pneumonia

Ventilator associated pneumonia is one of the most common hospital acquired infection in patients in intensive care units. It is associated with increased mortality, morbidity, length of hospital stays and increased cost of hospitalization. Ventilator associated pneumonia is a hospital acquired pneumonia that occurs at 48 hours or more after tracheal intubation with symptom onset 3 days or more after the hospital stay.

Characterize the epidemiology and microbiology

Incidence-

There is wide variation in incidence of ventilator associated pneumonia in different settings and different countries. Global incidence varies from 8 to 28 percent per 100 patients on ventilators.

Incidence pneumonia further increases with duration of mechanical ventilation - 3% /day for first 5days, 2%/day for 6-10days and 1%/day after 10 days.

Mortality rate is 27%. It is 43% with antibiotic resistant organism according to critical care societies collaboratives (CCSCs). Higher mortality rates were associated with increasing age, females, presence of comorbidities, admission to medical ICU, patients transfer from wards.

Mortality rate in VAP caused by Pseudomonas or Acinetobacter is as high as 76.

Microbiology:

Early-onset VAP is mainly caused by community pathogens with a favourable pattern of antibiotic sensitivity, whereas late-onset VAP is often caused by multidrug-resistant pathogens.

The predominant etiologic agents responsible for early onset (within 4 days) are streptococcus Pneumoniae. H. Influenza, Staphylococcus aureus, or uncommonly anaerobic bacteris like Proteus and Klebsiella.  

Organism responsible for late onset VAP(after 4 days) are mainly Pseudomonas aeruginosa, Acinetobacter, Enterobacter, vancomycin Methicillin resistant Streptococcus Aureus (MRSA). \

However in most of the cases infection is caused by multiple organisms, aerobic gram-negative bacteria including E. Coli, Klebsiella, Enterobacter, Pseudomonas, Actinobacteria are frequently isolated in specimen from the patients.

Describe the agent, and identify the host and the environment that is favourable for the infection.

Agent-

The following pathogens were identified as causative agent- streptococci, H. Influenza, E. Coli, methicillin-resistant Staphylococcus aureus (MRSA), Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia,

Host factors- Factors that increases risk for ventilator associated pneumonia are :

age >70 years, female sex, pre existing Lung Disease, viral Respiratory Tract Infections, severe associated Illnesses or co morbidities, depressed Mental Status, immunocompromising conditions, immobilisation that impede normal pulmonary toilet

Environment-

intensive care setting, contaminated hands, contaminated equipment’s, solutions, indiscriminate use of antimicrobial agents

Discuss how the infections spread and the types of prevention and
control measures

Spread of infection:

Bacteria enter the lower respiratory tract via following pathways: –

Aspiration of organisms from the oropharynx and GI tract (most common cause)- is primary route of entry of organisms in lower respiratory tract (LRT). Endotracheal tube keeps the vocal cords open-predispose to micro & macro aspiration of colonized bacteria from oropharynx to LRT. Another cause is Leakage of secretion containing bacteria around the ETT cuff.

Interrupted gastro-oesophageal sphincter due naso/ oro gastric tubes for feeding which keeps the gastro oesophageal sphincter open, or positioning of patient also lead to GI reflux and aspiration, increase oropharyngeal colonization and pathogenesis

Direct inoculation – Inhalation aerosols containing bacteria from other patients/ healthcare personnel’s, visitors, inadequate disinfection/sterilization of equipments, contaminated solutions/water for suctioning

Hematogenous spread – from intravenous catheter or other sites of infection in body

Prevention and control measures

1. Design of ICU -Adequate space, lighting, proper function of ventilatory system, facilities for hand washing, Isolation room.

2. Staffing- education, adequate number, quality, importance of personal cleanliness and attention to aseptic procedures.

3. Hand washing and Hand rubbing with alcohol-based solution.

4. Periodical bacterial monitoring and fumigation policy.

5. VAP BUNDLE – A group of interventions related to ventilator care when all are applied simultaneously there is enhanced reduction in incidence of ventilator associated pneumonia than each intervention applied separately. They are

a. Elevation of head end of bed to at least 30 degrees. Supine position is an independent risk factor for many complications in hospitalized patients.

b. Daily interruption of sedation, waking the patient unless contraindicated and assessment for readiness to wean to minimise duration of mechanical ventilation

c. Through oral care and suctioning

d. Peptic ulcer and deep vein thrombosis prophylaxis

6. Daily oral care - due to absence of mechanical chewing, dental plaque and saliva becomes reservoir for potential pathogens that can cause VAP. Intervention like

7. Tooth brushing twice daily

8. Rinsing of oral cavity with15 ml of alcohol free anti septic oral solution

9. Routine suctioning to prevent accumulation of secretions

10. Nasogastric feeding- monitoring of gastric residue and avoid overfeeding, elevate head end of bed after feeding

11. Suction devices- Policies for use and storage of such suction devices and suction catheter

12. Change catheter

13. Change suction catheter every day

14. Rinse with sterile water or NS

15. Allow to air dry Should be done using a 14 Fr sterile suction catheter to avoid trauma to mucosa

16. apply suction intermittently

17. Changing patient position or turning laterally 2 hourly

18. Monitoring for signs of complications, prompt recording and reporting

Identify a population and develop a hypothesis about possible causes
in a testable format with standard statistical notation (the null and the alternative)

Population for study:

Target population: All patients who are in intensive care units and are on mechanical ventilation

Accessible population: Patients in intensive care units of selected hospitals who are on mechanical ventilation and meet the inclusion criteria for the study

Alternative hypothesis:

There is significant difference in incidence of ventilator associated pneumonia on 7th day of ventilation among the patients receiving four hourly oral care versus those patients receiving twelve hourly oral care in intensive care units

Null hypothesis:

There is no significant difference in incidence of ventilator associated pneumonia on 7th day of ventilation among the patients receiving four hourly oral care versus those patients receiving twelve hourly oral care in intensive care units

Choosing controls

Controls will be chosen on the basis of following criteria

· No prior co morbidities that can affect incidence of ventilator associated pneumonia

· Dividing population in different strata according to age, sex, duration on ventilation, mode of admission direct to ICU or transferred from ward and then choosing samples from each strata purposively

· Random allocation of subjects to experimental and control groups after establishing quota for different age groups and sex.

· Study can be conducted retrospectively for ethical consideration

Answer 12

A . HAI are infections that patients get while receiving treatment for medical or surgical conditions, and many HAIs are preventable. The four most common types of HAIs are related to invasive devices or surgical procedures and include: Catheter-associatedurinary tract infection  (CAUTI) Central line- bloodstream infection (CLABSI) Surgical site infection (SSI). At any given time, about 1 in 25 inpatients have an infection related to hospital care. Here we discuss common HAI , symptoms, control measures.

B. Hospital-acquired infections are caused by viral, bacterial, and fungal pathogens; the most common types are bloodstream infection (BSI), pneumonia (eg, ventilator-associated pneumonia [VAP]), urinary tract infection(UTI), and surgical site infection (SSI).

Answer 13

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