Assigment .Apa seven . All instructions attached.

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Case Study 6: Outbreak in a Neonatal Intensive Care Unit

Session Overview Instructions For the purposes of this exercise, you will be asked to work in groups to participate in a healthcare associated infection investigation. Information regarding the scenario will be provided to you in parts, each of which will be followed by related discussion questions. Choose one group member to read each segment of information aloud to the rest of the group. After receiving the information, work as a team to formulate answers to each discussion question. Intended Audience All public health, medical, veterinary, pharmacy, emergency management, hospital and other professionals interested in public health preparedness and field epidemiology. Time Required (estimated) 90 minutes Learning Objectives

 Describe infection control practices in a healthcare setting  Calculate disease prevalence, case-fatality rate, and odds ratio  Create a histogram of cases over time  Choose an appropriate epidemiological study design, given information about an

outbreak  Interpret epidemiologic study results

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Case Study 6: Outbreak in a Neonatal Intensive Care Unit

Pre-Test

1. Which of the following describe contact precautions to prevent the spread of infection in a hospital setting?

a. Limiting patient movement b. Providing gown and gloves for patient c. Using dedicated equipment d. Cleaning and disinfecting patient room daily e. All of the above are contact precautions f. A, B, and D only

2. Prevalence is: a. number of deaths in infected persons

total number of infected persons b. number or cases (new and existing)

population at risk of infection c. number or cases (new and existing)

total number of infected persons d. none of the above

3. True or False: In a case control-study, the controls should represent the

population that gave rise to the case patients.

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Case Study 6: Outbreak in a Neonatal Intensive Care Unit

Student Guide

Situation Healthcare associated infections (HAIs), previously referred to as nosocomial infections, are acquired by patients during their treatment in a healthcare setting. HAIs are of serious concern in the healthcare field. Hospitals are an ideal setting for opportunistic pathogens because they house both highly infectious and highly susceptible patients. Simple infection control practices such as hand washing and thorough cleaning and disinfecting of items have greatly reduced the incidence of HAIs, yet such infections still occur. In the U.S. alone, it is estimated that HAIs are responsible for 1.7 million infections annually, 75,000 of which are fatal. Most hospitals employ an infection control practitioner (ICP) who monitors cases of disease throughout the hospital and ensures that proper hygiene and infection control procedures are followed throughout the hospital. Additionally, many hospitals employ a hospital epidemiologist to assist the ICP in surveillance and epidemiologic investigations, when necessary. The following case study examines what can happen when there is a lapse in surveillance and cases go unreported, and is loosely based on an actual outbreak that occurred in a children’s hospital in the United States.

Update 1: Day 1 You are the hospital epidemiologist in the regional children’s hospital in your state. You receive a call from the infection control practitioner, who was notified of a patient with early signs of a systemic infection by an attending physician in the neonatal intensive care unit (NICU). Despite a variety of differential diagnoses, the physician began antibiotic treatment, knowing that neonates such as this patient are at high risk of developing neonatal sepsis. The physician ordered blood and serum samples, and requested a cerebrospinal fluid (CSF) sample be collected as soon as possible. The infection control practitioner asks for your help in investigating the circumstances of this case.

1. What pertinent information would be helpful for you and the physician to know

regarding this patient? 2. What infectious agents would be of greatest concern to the physician?

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Update 2: Day 2 You find out from the ICP that the patient is 2 week-old infant born prematurely at 33 weeks with underdeveloped lungs and has been intubated in the NICU since birth. The infant began showing signs of cyanosis and the nurse caring for the infant noticed the

child had a rapid heartbeat and a fever of 101.5F.

After initial antibiotic treatment, the patient’s fever dropped to 100.8F but the heart rate remained elevated. A rapid laboratory test revealed gram-negative rods in the patient’s blood and CSF, although specific lab results that will identify the pathogen are still pending. The finding of gram-negative rods in the blood is particularly worrisome and indicative of bacterial sepsis, but the infant appears to be responding well to the antibiotic treatment. In thinking about the source of the infection, the physician reviews the chart of the mother to see if she could have been the source. Although the baby was born premature, the mother showed no signs of infection upon admission to the hospital.

3. Could the mother be the source of infection, why or why not? 4. What might be other sources of infection in this patient? 5. Would you consider this a hospital acquired infection? Discuss what factors would

lead you to determine if an infection is hospital acquired.

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Update 4: Day 2 You receive a call from the ICP, and the results of the laboratory diagnostic tests came back positive for Pseudomonas aeruginosa (su-doe-mo-nas air-rudge-i-nosa). You and the ICP are immediately concerned about the potential spread throughout the NICU and the rest of the hospital. Below is what you know about this pathogen: P. aeruginosa is one of the most common hospital acquired pathogens and can cause severe infections in hospitalized patients. It occurs naturally in the environment, and can be found in soil, water, plants and animals. P. aeruginosa is an opportunistic pathogen, meaning that it predominately infects persons with compromised immune systems. Infection with the bacteria can be localized or systemic if it enters the bloodstream. A 2011 study in the New England Journal of Medicine showed that P. aeruginosa caused 7% of all healthcare-associated infections, including 13% of healthcare associated pneumonia cases. Notably, there are now multidrug resistant strains of P. aeruginosa that cause approximately 400 deaths per year in the U.S. Within the healthcare setting, outbreaks of P. aeruginosa have been linked to contaminated respiratory, endoscopic, urodynamic and pressure monitoring equipment, contaminated sinks, products (e.g., eye drops), tap and bottled water, and even healthcare workers. P. aeruginosa infection is treatable, although acute infections in immunocompromised patients have resulted in a 30% - 60% mortality rate.

6. What steps should the infection control practitioner take to ensure the infection does

not spread to other patients? 7. Considering the information given, does it warrant a full investigation into the

source of the infection?

Update 5: Day 3 In looking over hospital surveillance data given to you by the ICP, you find an alarming trend that the new ICP did not notice. This case of is part of a growing number of P. aeruginosa infections in the NICU reported over the past year, and there have been several cases of P. aeruginosa this month.

8. Aside from an outbreak of disease, what might be other explanations of a rise in

reportable diseases? Are these explanations likely for the observed causes of P. aeruginosa?

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Update 6: Day 3 Although there have been several cases other of P. aeruginosa infection throughout the hospital, the cases outside the NICU are comparable to baseline numbers and are not out of the ordinary. Knowing this, you begin to wonder if the NICU cases are linked to a common source. You decide to do some preliminary research on NICU patients in your hospital and discover the following: Since January of last year, 519 infants were admitted to the NICU, with 439 staying for a period longer than 48 hours, thus putting them at a higher risk of contracting the infection. Forty-six patients were culture positive for P. aeruginosa, including the most recent patient, which sparked your interest in these infections. Despite the success in treating the most recent patient, 16 infected patients in the NICU died from their infection.

9. What is the prevalence of P. aeruginosa infections in patients who visited the NICU

more than 2 days? Prevalence is a proportion that measures disease in a given population that is considered to be at risk. Prevalence is found by dividing the number of infected persons by the total number of people in the population at risk:

Prevalence = number or cases (new and existing)

population at risk of infection 10. Calculate the case-fatality rate of infected patients from the NICU since January of

the previous year. Case-fatality rate is the proportion of deaths in infected persons among the total number of infected persons (Note: Despite its name, a case fatality rate is not a true rate, but simply a proportion).

Case-fatality rate = number of deaths in infected persons total number of infected persons

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Update 7: Day 3 Looking back at past cases since the previous January, you are able to quantify the magnitude of P. aeruginosa infection over a 15-month period. All 46 cases were admitted to the small baby room and mechanically ventilated. In all the cases, infections were either systemic (in bloodstream) or localized in and around the endotracheal tube (ETT). All cases were laboratory confirmed. No P. aeruginosa was isolated from skin or wound cultures. Table 1 below summarizes the results of your chart review:

Table 1. Cases of P. aeruginosa, January 2014-March 2015

Month of Diagnosis Site of infection

Month of Diagnosis

Site of infection

January 2014 ETT August 2014 ETT

February 2014 ETT August 2014 ETT

March 2014 Blood August 2014 Blood

March 2014 ETT September 2014 ETT

April 2014 Blood September 2014 ETT

April 2014 ETT November 2014 Blood

April 2014 ETT November 2014 ETT

April 2014 ETT December 2014 Blood

May 2014 Blood December 2014 Blood

May 2014 ETT December 2014 ETT

May 2014 ETT December 2014 Blood

May 2014 ETT January 2015 ETT

May 2014 Blood January 2015 ETT

May 2014 ETT January 2015 ETT

May 2014 ETT January 2015 ETT

June 2014 ETT February 2015 ETT

June 2014 ETT February 2015 ETT

June 2014 ETT February 2015 ETT

June 2014 ETT March 2015 ETT

June 2014 ETT March 2015 Blood

June 2014 Blood March 2015 Blood

July 2014 Blood March 2015 Blood

July 2014 ETT March 2015 Blood

11. Construct a histogram plotting the number of cases, by type of infection, for each

month of diagnosis beginning with January 2014 and ending in March 2015. (Hint: Plot Blood and ETT on the same graph, differentiated by shading).

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12. Look at the histogram you created. Is this histogram an epidemic curve? Why or why not?

13. What are the next steps in determining the source of the outbreak? 14. Considering that all cases are on mechanical ventilators and a large number of

patients had bacterial colonization on endotracheal tubes, what control measures, if any do you implement?

Update 8 Based on the findings of your research of recent infections in the NICU, you are interested in the possible link between endotracheal tubes and the P. aeruginosa infections, but do not want to narrow your focus before obtaining more evidence to confirm your suspicions. You begin by requesting environmental samples from surfaces in the NICU: ventilator equipment, faucets, sink drains, hand lotion, and cleaning agents. Worried about infections spread via healthcare workers, you obtain cultures from ear canals and hands of any healthcare worker working in the NICU, as ear canals and hands are common colonization sites. You also questioned the workers about recent history of skin or ear infections, and workers’ fingernail length was assessed by the ICP and recorded. The results of the environmental assessment reveal that P. aeruginosa was isolated from 2 sink drains—no other samples tested positive. From the healthcare worker specimen collection, you find that 2 NICU nurses had P. aeruginosa isolated from their hands, but not from their ear canals. You also note that on inspection of their hands, one nurse had long natural fingernails (nurse A) and the second nurse had short natural fingernails (nurse B). You decide to conduct an epidemiologic investigation to look at factors that might have contributed to P. aeruginosa infection.

15. Given this information what type of epidemiologic study design would you use? 16. You decide to conduct a case-control investigation. Discuss what criteria should be

used to classify cases and controls.

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Update 9 In this study, cases were defined as intubated patients with laboratory confirmed P. aeruginosa infection that stayed in the NICU longer than 48 hours during the period between January 1, 2014 and March 31, 2015. Controls were intubated patients admitted to the NICU for more than 48 hours between January 1, 2014 and March 31, 2015. 135 controls were randomly selected from NICU chart reviews of patient visits during the study period and compared against the 46 cases. Of all the experimental variables, you find that contact with an infected nurse was slightly greater than 1, but exposure to the infected nurse with long fingernails was much greater.

17. The odds ratio for contact with an infected nurse was 1.21, with a 95% confidence

interval of 0.35 - 4.65. Do these results imply that contact with an infected nurse was a risk factor for developing P. aeruginosa infection? Why or why not?

Contact with Infected Nurse with long

fingernails Cases Controls

Yes 41 75

No 5 60

18. From table 2 above, calculate the odds of acquiring infection if you had contact with

the infected, long-nailed nurse within this study. The odds of acquiring infection from an infected nurse is found by dividing the number of cases who had contact with the nurse by the number of controls having contact with the nurse.

19. Using the same table, calculate the odds of acquiring infection if you did not have

contact with the long-nailed infected nurse. The odds of being a case if you did not have contact with the long-nailed infected nurse is found by dividing the number of cases who did not have contact with the nurse by the number of controls who did not have contact with the nurse.

20. Calculate the disease odds ratio using the data provided. A disease odds ratio is

found by obtaining the ratio of the probability of being a case among the exposed and the probability of being a case among the non-exposed. These two probabilities have been found in questions 18 and 19, and were 0.54 and 0.083.

Disease odds ratio = odds of infection & having contact with long-nailed infected nurses odds of infection & not having contact w/ long-nailed infected nurse

Table 2. Number of Cases and Controls in Contact with an Infected Nurse

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Conclusion Based on the results of your investigation, it was recommended that nurses in the NICU keep short to medium length nails (<1/4 inch from nailbed). As an added precaution, the nurses carrying P. aeruginosa were assigned to tasks that did not involve contact with NICU patients, but returned to NICU patient care after it was determined they were no longer carrying the bacteria. With the implementation of these recommendations, the number of P. aeruginosa cases declined. Restrictions preventing fingernail length had been in place in certain hospital departments (most notably operating rooms). The investigation on which this study was based led to a more widespread acceptance of fingernail length guidelines.

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References Anderson-Berry AL, Bellig LL, Ohning BL. Neonatal sepsis. eMedicine. 2014. Available at: http://www.emedicine.com/PED/topic2630.htm. Accessed April 6, 2016. Aschengrau A, Seage GR. Essentials of Epidemiology in Public Health. Sudbury: Jones and Bartlett Publishers, Inc; 2003. Bodey GP, Bolivar R, Fainstein V, Jadeja L. Infections caused by Pseudomonas aeruginosa. Rev Infect Dis 1983; 5: 279-313. Centers for Disease Control and Prevention. Healthcare-associated infections (HAIs). 2015. Available at http://www.cdc.gov/HAI/surveillance/index.html. April 6, 2016. Centers for Disease Control and Prevention. Pseudomonas aeruginosa in healthcare settings. 2014. Available at http://www.cdc.gov/HAI/organisms/Pseudomonas.html. April 6, 2016. Magill SS, Edwards JR, Bamberg W, Beldavs ZG, Dumyati G, Kainer MA, et al. Multistate point-prevalence survey of health care-associated infections. N Engl J Med 2014; 370:1198-1208. Moolenaar RL, Crutcher JM, San Joaquin VH, et al. A prolonged outbreak of Pseudomonas aeruginosa in a neonatal intensive care unit: did staff fingernails play a role in disease transmission? Infect Control Hosp Epidemiol 2000; 21:80-85. Naze F, Jouen E, Randriamahazo RT, Simac C, Laurent P, Bleriot A, et al. Pseudomonas aeruginosa outbreak linked to mineral water bottles in a neonatal intensive care unit: fast typing by use of high-resolution melting analysis of a variable-number tandem- repeat locus. J Clin Microbiology 2010;48(9):3146-3152. Occupational Safety and Health Standards (OSHA). 1910.1030. Bloodborne pathogens: Toxic and Hazardous Substances. Occupational Safety and Health Administrator. US Department of Labor.