1: Infection Control

Case 1
Infection Control

Medical History

This patient donates blood regularly, and at her most recent visit to the blood center, the screening report was positive for Hepatitis C (HCV). The facility reviewed past donation screening records, going back several years, and the reports were all negative for HCV. As mandated by state legislation, the blood center reported the incidence of HCV to the state health department. The patient was seen by her primary care physician who interviewed her about potential risk factors commonly associated with HCV and confirmed the diagnosis of acute HCV with genotype 1a. The physician reported back to the state health department that the only possible risk factor was her visit to the oral surgeon who extracted two third molars with IV sedation.

The state health department sent investigators to the dental facility that was believed to be the source of infection. After interviewing and testing several thousand patients, the investigators identified 96 people with HCV. Of these people; genetic testing identified the Hepatitis C genotype of the case patient that matched with another individual who had oral surgery on the same day. Further investigation revealed a contaminated sedation medication vial that was used for the infected patient and reused for the case patient. The final report included several infection control violations as probable cause for disease transmission (adapted from OK.gov 2016).

The patient’s medical history did not reveal any other significant medical findings or conditions. Vital signs were within normal limits.

Dental History

Patient is aware of her dental health and the importance of regular checkups. She recently visited the oral surgeon for surgical extractions with no oral complications. She is now concerned about transmission of infectious disease.

Social History

Patient is married with two adult children and lives in the suburbs. She is a human resource consultant.

Dental Examination

Extraoral exam revealed no significant findings. Intraorally the patient presents with generalized pink gingiva with light supragingival calculus and biofilm. Class I malocclusion with slight mandibular anterior crowding was noted. Teeth #1 and #16 were removed four months ago. Periodontal examination reveals generalized maxillary and mandibular probing depths of 3–4 mm with bleeding upon probing on posterior quadrants and 1 mm recession on the premolars. Radiographs were current.

Dental Hygiene Diagnosis

Problems Related to Risks and Etiology
Dental fear of disease transmission HCV diagnosis
Dental hypersensitivity Gingival recession
Potential for periodontal disease Generalized light supragingival calculus and biofilm with bleeding upon probing posteriorly on all quadrants

Planned Interventions

Planned Interventions
(to arrest or control disease and regenerate, restore or maintain health)
Clinical Education/Counseling Oral Hygiene Instruction
Adult Prophylaxis
5% NaF fluoride varnish to prevent root caries
Educate about recession prevention and dentinal sensitivity reduction
Educate about periodontal disease and disease prevention
Educate on current infection control practices in the dental office
Modified Stillman’s brushing technique
Interdental cleaning with interproximal brushes
Recommend dentinal hypersensitivity toothpaste with fluoride

Progress Notes

The patient arrived for her appointment 30 minutes before her appointment time. Medical, social, and dental history assessed. Review and tour of infection control office practices. Patient felt comfortable, and the hygiene appointment continued. Oral, dental, and periodontal exams were updated. Treatment plan explained and accepted. Biofilm management was reviewed and tailored to her needs. A recall appointment was scheduled.

History and Clinical Pathophysiology

Gastrointestinal symptoms may appear within two weeks to six months after infection with HCV. HCV is acute, asymptomatic, and cleared by the body within six months approximately 15–25% of the time (Takehara and Hayashi 2007; Heymann 2015). Of the remaining acute cases, 75–85% will become chronic, and can go undetected for 20–30 years until symptoms of cirrhosis and hepatocellular carcinoma are diagnosed (Heymann 2015; CDC.gov 2016).

Bloodborne pathogens, Hepatitis A and B were isolated in the 1970s, though an unidentified hepatitis type infection continued to appear in blood transfusions and was labeled Non‐A or Non‐B Hepatitis (NANBH). The molecular structure of HCV was isolated in 1989 from the plasma of infected chimpanzees (Choo et al. 1989) and subsequent serologic testing provided insight into epidemiologic details and disease transmission. HCV is an acellular, obligate parasite that replicates ribonucleic acid (RNA) genetic material (Figure 3.1.1) within liver hepatocytes and is only transmitted by contact with infected human blood (Chevaliez and Pawlotsky 2006; Takehara and Hayashi 2007; Pfaender et al. 2015). The virus can survive in plasma while drying on fomites for up to 16 hours (Kamili et al. 2007), and cool (40° F) environments for up to five months (Ciesek et al. 2010). HCV is isolated into six genetic groups labeled in chronological order of discovery with Arabic numerals (1–6), and subtypes identified with lower case letters (a, b, c) (Choo et al. 1989).

Schematic representation of the major steps of HCV life cycle depicting the receptor binding and endocytosis, and with arrows from fusion and uncoating of (+) RNA to translation and prolyprotein processing, etc.

Figure 3.1.1: Schematic representation of the major steps of HCV life cycle.

Source: Courtesy of Dubuisson (2007).

Diagnosis of HCV is made by the detection of antibodies to the hepatitis virus (anti‐HCV) in a blood test called an enzyme immunoassay (EIA). A patient with a positive EIA should confirm the diagnosis with a more sensitive immunoassay that tests specifically for the presence of HCV RNA (CDC.gov 2016).

In 1998 the National Center for Chronic Disease and Health Promotion (CDC) collected epidemiological data on the prevalence of HCV by testing high‐risk individuals (Table 3.1.1). The data revealed that the largest cohort, who tested positive, was born between 1945 and 1965; “five times higher than among adults born in other years” (CDC.gov 2012). The CDC also reported that 45–85% of these persons were unaware of their HCV status, and in 2012 published recommendations that individuals born between 1945 and 1965 – “baby boomers” – be tested for HCV (CDC.gov 2012).

Table 3.1.1: Individuals with high risk for HCV.

Source: (CDC.gov, 2012).

  • Persons‐Who‐Inject‐Drugs (PWID)
  • Hemodialysis patients
  • Patients who had a blood transfusion or organ transplant before July 1992 or received clotting factor concentrates produced before 1987
  • Persons with a known exposure to HCV by a needle stick
  • Persons born to an HCV‐infected mother
  • Patients with liver inflammation
  • Individuals with HIV

Undetected chronic HCV is the leading cause of liver transplantation in the United States (CDC.gov 2012). Barriers to risk testing by individuals in this cohort include lack of health insurance, alcoholism, and provider knowledge of recommendations, testing methodology, and current guidelines (CDC.gov 2012).

Employers of health‐care providers must abide by the Occupational Safety & Health Administration (OSHA) Bloodborne Pathogens Standard (29 CFR 1910.1030). This federal law mandates that employers of health‐care workers provide a plan for exposure control, engineering and safe work practice controls, hepatitis B (HBV) vaccinations, hazard communication and training, and maintain documentation of exposure incidents. This law also requires compliance with universal precaution guidelines to prevent occupational exposure to bloodborne pathogens and cross contamination (OSHA.gov 1991). These guidelines instruct health‐care workers to consider all patients as potential carriers of bloodborne disease and thus adhere to precautions in the form of personal protective equipment (PPE) – gloves, masks, and eyewear at all times when caring for them. The reasoning behind this approach was that disclosure by infected patients could not always be corroborated through the process of obtaining medical history information or observing visible symptoms, and health‐care providers needed to be protected.

The Standard Precautions Standard, revised Universal Precautions in 2007, by including guidelines for Safe Injection Practices and Respiratory Hygiene/Cough Etiquette (CDC.gov 2007). Safe Injection Practices identified a need to contain outbreaks of HCV and HBV that occur by the “reinsertion of used needles into a multiple‐dose vial or solution container (e.g. saline bag) and use of a single needle/syringe to administer intravenous medication to multiple patients” instead (CDC.gov 2007).

The CDC Healthcare Infection Control Practices Advisory Committee (HICPAC) Guideline for Disinfection and Sterilization in Healthcare Facilities (CDC.gov 2008) and the Guidelines for Infection Control in Dental Health‐Care Settings (CDC.gov 2003) include recommended procedures for instrument processing. In general, the guidelines identify and categorize disinfection and sterilization procedures of patient‐care items by the risk of disease transmission: critical, semi‐critical and non‐critical (Table 3.1.2).

Table 3.1.2: There are three categories of patient‐care items depending on their intended use and the potential risk of disease transmission.

Instrument Type Features Examples
CRITICAL Critical items penetrate soft tissue or contact bone, the bloodstream, or other normally sterile tissues of the mouth. They have the highest risk of transmitting infection and should be heat‐sterilized between patient uses.
Alternatively, use sterile, single‐use disposable devices.
Examples include surgical instruments, periodontal scalers, scalpel blades, and surgical dental burs.
SEMI‐CRITICAL Semi‐critical items contact only mucous membranes and do not penetrate soft tissues. As such, they have a lower risk of transmission.
Because most items in this category are heat tolerant, they should be heat sterilized between patient uses. For heat‐sensitive instruments, high‐level disinfection is appropriate.
Examples of semi‐critical instruments include dental mouth mirrors, amalgam condensers, and impression trays. Dental handpieces are a special case. Even though they do not penetrate soft tissue, it is difficult for chemical germicides to reach the internal parts of handpieces. For this reason, they should be heat sterilized using a steam autoclave or chemical vapor sterilizer.
NON‐CRITICAL AND OTHER DEVICES Non‐critical instruments and devices only contact intact (unbroken) skin, which serves as an effective barrier to microorganisms. These items carry such a low risk of transmitting infections that they usually require only cleaning and low‐level disinfection. If using a low‐level disinfectant, according to OSHA, it must have a label claim for killing HIV and HBV. However, if an item is visibly bloody, it should be cleaned and disinfected using an intermediate‐level disinfectant before use on another patient. Examples of instruments in this category include X‐ray head/cones, face bows, pulse oximeter, and blood pressure cuff.

Patient‐care items that penetrate soft tissue and come in contact with blood are categorized as critical and should be sterilized by heat (Table 3.1.2). Sterilization is defined as the inactivation of cellular processes and coagulation of proteins resulting in cell death. The most common equipment in dental offices used for sterilization of heat tolerant instruments is either a gravity displacement or high‐speed pre‐vacuum steam under pressure autoclave. Cleaned and packaged instruments must be definitively placed inside the autoclave to allow for direct contact and steam circulation over a prescribed period of time. Dental health‐care providers should follow manufacturer instructions for use, monitoring gauges for the attainment of pressure and temperature, and allow for minimum sterilization time to reach asepsis. Recommended sterilizing times and temperatures are 30 minutes at 250 °F for a gravity displacement autoclave and four minutes at 132 °F for a high‐speed pre‐vacuum autoclave. Monitoring of sterilization effectiveness is recommended for each procedure. Internal and external indicators, such as heat sensitive tape or internal chemical indicators can verify that a package was exposed to heat for a period, though do not prove that sterilization had been achieved. The placement of heat resistant biological indicators (BIs) containing Geobacillus stearothermophilus is used to confirm that sterilization has been achieved. Spores are more resistant and have a higher threshold to heat sterilization than the common microbial population found on patient‐care instruments (CDC.gov 2003, 2008). Analysis of the BI with evidence of spore death indicates that any pathogen less resistant had also been inactivated.

As highly infectious diseases emerge and are identified, infection control guidelines are revised to accommodate new information and are upheld by state agencies and federal law. Failure to adhere to these guidelines can often have serious consequences for both the provider and the patient.

Take‐Home Hints

  • More than 75% of baby boomers in the United States are HCV infected.
  • CDC reported that acute (new) cases of HCV have almost doubled since 2012.
  • CDC estimated that 2.7–3.9 million people in the United States have chronic HCV.
  • Most persons with chronic HCV are asymptomatic.

Jul 18, 2020 | Posted by in Dental Hygiene | Comments Off on 1: Infection Control

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