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Hospital Acquired Infections

Hospital Acquired Infections, also known as nosocomial or healthcare-associated infections (HAI) are explained as infections without evidence and not present of incubation at the time the patient was admitted to a healthcare facility. As a better definition/reflection of the expansive healthcare facility settings presently available to patients, the term healthcare-associated infection is more accurate and the term currently used.

This article focuses on the 3 major healthcare-associated infection sites: urinary tract infection, pneumonia, and bloodstream infection, but primarily concentrates on the respiratory aspect: Pneumonia.

Following a few hours after admission, a patient’s natural flora starts to take on characteristics of the bacterial pool surrounding them. Clinically symptomatic infections that become evident 48 hours after hospitalization are deemed hospital-acquired. Symptomatic infections that occur after the patient is discharged from the healthcare facility can also be considered healthcare-associated if the infection was acquired during the healthcare facility stay.

Hospital-based departments and programs of prevention and control and surveillance of healthcare-associated organisms have been in operation since the 1950s. It is expected and monitored that all healthcare professionals take pride with strict adherence to all infection control policies and procedures.

Continued monitoring, along with strict programs of infection control, not only lead to diminished healthcare-associated organisms but also improved resources and prioritization of efforts to increasing medical care quality.

It is of wide-range concern in the medical field that healthcare-associated infections be controlled. They can be systemic or localized, can be associated with medical devices or blood product transfusions or may involve any body system.

Endogenous or exogenous infectious agents may cause healthcare-associated infections.
GI, nasopharynx, or genitourinary tracts normally include microorganisms and may be endogenous sources. Sources that are not part of the patient are considered exogenous. Examples include medical personnel, visitors, the healthcare environment and equipment.
Patient risk factors for invasion include length of in-patient hospital stay, underlying immunocompromised state and severity of illness.

United States
Healthcare-associated acquired infections are estimated to occur in 5% of all admissions in the United States.
International
Both resource-poor and developed countries are faced with the burden of healthcare-associated infections.

Mortality/Morbidity
Healthcare and mortality costs and excess length of stay are the result of healthcare-associated infections. An estimated 1.7 million healthcare-associated infections occurred in the United States, resulting in 99,000 deaths in 2002. In March 2009, annual direct medical costs of healthcare-associated infections that ranged from $28-45 billion were reported by the CDC.

Additionally, a 2009 CDC report showed that intensive care units in the United States, there were 25,000 fewer central line-associated infections than in 2001, showing a 58% decrease. An estimated 27,000 lives were saved between 2001 and 2009, and prevented potential $1.8 billion total health-care costs. Best practices coordinated efforts from professional societies, federal and state agencies, and healthcare personnel in implementing insertion of central lines played a role in this achievement.

Sex
Healthcare-associated organisms do not have a discernible sex choice.
Age
Healthcare-associated infections happen in both pediatric and adult populations. Bloodstream organisms, followed by pneumonia and UTI’s are the most common healthcare-associated infections in children. The most common infections in adults are UTI’s (urinary tract infections). Babies with extremely low birth weight (≤ 1000 g) and children in either the NICU or PICU have increased rates of healthcare-associated acquired organisms.

History
Healthcare-associated pathogen infections are most regularly caused by bacterial, viral, and fungal pathogens. These organisms should be studied in all febrile patients admitted for a non-febrile disease or those who develop clinical symptoms unexplained by the admitting diagnosis.
Patients who have healthcare-associated infections are likely caused by fungal and bacterial pathogens and have a predisposition to infection caused by invasive measures such as the placement of intravascular lines, urinary catheters and invasive endotracheal intubation. In bloodstream infections, ninety-one percent were in patients with central intravenous lines (CVL). Of pneumonia cases 95% were in patients on mechanical ventilation, an of urinary tract infections 77% were in patients with catheters in the urinary tract.

Physical
In addition to the signs and symptoms of systemic infection (i.e. tachycardia, skin rash, fever, general malaise), the introduction/source of healthcare-associated infections may be indicated by the equipment/instrumentation used in various procedures. For instance, an endotracheal tube may be associated with pneumonia, tracheitis or sinusitis. An intravascular catheter may be the source of a line infection or phlebitis and a Foley urinary catheter may be identified with a urinary tract infection.
Patients presenting with pneumonia signs and symptoms may have purulent sputum, fever, cough, and abnormal chest sound findings such as wheezes, crackles or decreased breath sounds.

Causes
Representing 64% of all healthcare-associated infections, the top 3 major sites of origin were bloodstream organisms (28%), pneumonia (21%), and urinary tract infection (15%). An invasive device was strongly associated with all of these infections.

A remaining and strong cause of healthcare-acquired infections is Methicillin-resistant staphylococcus aureus (MRSA).

Surgical site infections (SSI) happen within 30 days after the operative procedure and occur with an implant within 1 year.

The healthcare-associated, prevalent cause of gastroenteritis is Clostridium difficile.

Laboratory testing should be guided by the results of a close physical examination review.
Always guide yourself with caution when interpreting laboratory results since not all bacterial or fungal growth are pathogenic on culture. Evidence on cultures may be simple colonization and microbial growth. Always let the following guide you:

• Clinical presentation and evaluation of the patient
• Reason test was obtained
• Method by which the specimen was obtained (i.e. urine culture obtained through a new catheter will less likely be contaminated by microbes or colonization).
• Further conclusive, significant evidence of other infection evidence (i.e. the importance of bacterial growth evidence on suctioned sputum tracheal culture is supported by the presence of X-Ray changes and clinical pneumonia signs and symptoms).

Pneumonia
Acute stage phase reactant (C-reactive protein, WBC count, sedimentation erythrocyte rate) can be raised but not targeting in determining that the pneumonia is viral or bacterial.
A decrease in oxygen saturation and worsening hemodynamics are signs to determining the cause of pneumonia.
The evidence of a new infiltrate on chest X-Ray is a possible pneumonia; however, it may be difficult to differentiate from decrease in air movement/atelectasis.
Sputum gram stain and cultures may be helpful. But, young children may be unable to effectively produce a sputum sample and these phlegm samples could be contaminated by saliva and upper respiratory tract organisms. A sufficient sputum sample will have less than 10 squamous epithelial cells and greater than 25 neutrophils per low-power field, in a culture with strong infection growth.

In sputum samples obtained via suctioning of endotracheal, nasotracheal, or tracheostomy tubes, the sample may not be reliable due to the presence of upper respiratory tract organisms. More reliable methods to obtain specimens for laboratory/microbiologic testing include bronchoalveolar lavage and thoracentesis.
Significant efforts to distinguish between ventilator-associated pneumonia , tracheobronchitis and tracheobronchial colonization and may well prevent non-antibiotic treatment.
Quick diagnostic laboratory testing will be valuable in specific diagnostic patient cases. Examples include antibody test/direct fluorescent for Legionella; polymerase reaction chain tests for Bordetella pertussis; modified acid-fast stains for mycobacteria; Pneumocystis jiroveci; for influenza and respiratory syncytial virus: immunofluorescence tests.

Medical Care
Along with administration of empiric broad-spectrum antimicrobial therapy, symptomatic treatment of shock, hypoventilation, and other complications should be managed.

Pneumonia
Following careful examination of initial cultures of endotracheal suction matter and bronchial lavage wash and tracheal sputum, antibiotic empiric therapy should be streamlined and broad. The determining decision of empiric antibiotic therapy shall certainly consider the risk for pathogens that are multidrug-resistant (MDR). Risk factors for multi-drug resistant therapy include therapy that’s antimicrobial in nature that was received during the last 90 days, currently hospitalized with a stay of 5 or more days, immune or hospital suppression and higher evidence of community antibiotic resistance.
A clear consensus has not been concluded concerning the length of antimicrobial treatment for ventilator-acquired pneumonia (VAP). Many physicians treat with antibiotics for a duration of 14-21 days. However, shorter duration of course antibiotic therapy (about 1 week) may be sufficient for some patients.
Antiviral drugs against influenza have been utilized to treat symptomatic patients and those with chronic lung diseases or immunodeficiency to limit mortality and morbidity.

Prevention
Vigilant adherence to infection control protocols in any healthcare facility is paramount in preventing hospital-associated infections. All healthcare professionals are acutely aware of the risk factors of cross-contamination with use of equipment and therefore follow strict instructions when using and then sterilizing this equipment. There are highly qualified professionals in healthcare facilities whose sole purpose and responsibility is to monitor that these infection control protocols are being followed.