Healthcare-Associated Infection and Exposure to Infected or Colonized Concurrent Roommates and Prior Bed Occupants

This dissertation examines factors associated with healthcare-associated infections (HAIs) in four acute care hospitals located in New York City. Specifically, this investigation focuses on the role that the physical environment plays with regard to patient-to-patient transmission. The initial analyses describe the scope of the problem by reporting the incidence of HAIs and antimicrobial resistance over a seven-year period in the study institutions. In total, 19,052 HAIs were identified among 761,426 discharges. HAI rates fell over time within all hospitals and for all organisms and infection types included in the study, and the odds of acquiring an HAI decreased significantly over time for all organisms. Resistance levels were stable for Enterococcus spp., Staphylococcus aureus, Acinetobacter baumannii, and Streptococcus pneumoniae. Multidrug resistance increased for Pseudomonas aeruginosa and decreased for Klebsiella pneumoniae, though imipenem resistance among K. pneumoniae climbed sharply in 2011. A systematic literature review is presented to summarize what is known and unknown about how patients’ exposure to infected or colonized concurrent roommates and prior bed occupants affects their risk of developing HAIs. Eighteen articles meeting the inclusion criteria were identified. More than half reported at least one statistically significant positive association between the infection/colonization status of a roommate or previous room occupant and the development of HAIs. Only a single article identified a statistically significant negative association. The remainder found no associations that reached statistical significance, though this may be due to the fact that they were insufficiently powered. The dissertation concludes with a matched case-control study designed to quantify the association between having a prior bed occupant or roommate with a positive blood, respiratory, urine, or wound culture and subsequent infection with the same organism. In a multivariable analysis controlling for patient characteristics and mutually controlling for each exposure, the odds of being exposed to a prior bed occupant with the same organism were 5.83 (95% Confidence Interval [3.62, 9.39]) times greater for cases versus controls and the odds of being exposed to a roommate with the same organism were 4.82 [3.67, 6.34] times greater

Burden of present-on-admission infections and health care-associated infections, by race and ethnicity

Background: In the United States incidence of sepsis and pneumonia differ by race, but it is unclear whether this is due to intrinsic factors or health care factors. Methods: We conducted a study of 52,006 patients hospitalized during 2006-2008 at a referral hospital in upper Manhattan. We examined how the prevalence of present-on-admission and health care-associated infection compared between non-Hispanic blacks, Hispanics, and non-Hispanic whites adjusting for sociodemographic factors, admission through the emergency department, and comorbid conditions. Results: Non-Hispanic blacks had 1.59-fold (95% confidence interval [CI], 1.29-1.96) and 1.55-fold (95% CI, 1.35-1.77) risk of community-acquired bloodstream infection and urinary tract infection compared with non-Hispanic whites. Hispanic patients had 1.31-fold (95% CI, 1.15-1.49) risk of presenting with community-acquired urinary tract infection compared with non-Hispanic whites. Controlling for admission through the emergency department, comorbidity, and neighborhood income attenuated the differences in prevalence of infections. Conclusions: We found that health disparities in present-on-admission infections might be largely explained by potential lack of ambulatory care, socioeconomic factors, and comorbidity

Risk factors for hospital-acquired antimicrobial-resistant infection caused by Acinetobacter baumannii

Background Acinetobacter baumannii can cause serious healthcare-associated infections (HAIs) and the incidence is increasing, with many strains now resistant to multiple antibiotic classes. The aims of this study were to examine factors associated with HAIs caused by antimicrobial-resistant as compared with antimicrobial-susceptible strains of A. baumannii and to investigate trends in the incidence of resistance over time. Electronic data from two U.S. hospitals in a large urban healthcare system in over the years 2006–2012 were used for the analysis. Multiple logistic regression was used to explore risk factors for infection with A. baumannii resistant to ampicillin or ampicillin/sulbactam in the bloodstream, urinary tract, and respiratory tract. The Cochran-Armitage trend test was used to explore resistance trends over time. Findings A total of 671 adults with first-time A. baumannii infection were included in the analysis; 302 isolates (45 %) were resistant to ampicillin or ampicillin/sulbactam and 369 (55 %) were susceptible. In the multivariable analysis, significant risk factors included longer length of stay prior to infection (Odds Ratio [OR] = 1.03; 95 % Confidence Interval [CI]: 1.01, 1.04), hospital A versus B (OR = 0.35; 95 % CI: 0.13, 0.93), and antibiotic use prior to infection (OR = 2.88; 95 % CI: 1.02, 8.13). Resistance was more common in respiratory infections (OR = 2.96; 95 % CI: 1.04, 8.44). No trend was found between year of infection and resistance. Conclusions The risk factors we identified are consistent with previous findings, but we found no evidence in this population that resistance to ampicillin or ampicillin/sulbactam was increasing over time

Personal and Household Hygiene, Environmental Contamination, and Health in Undergraduate Residence Halls in New York City, 2011

Background: While several studies have documented the importance of hand washing in the university setting, the added role of environmental hygiene remains poorly understood. The purpose of this study was to characterize the personal and environmental hygiene habits of college students, define the determinants of hygiene in this population, and assess the relationship between reported hygiene behaviors, environmental contamination, and health status. Methods: 501 undergraduate students completed a previously validated survey assessing baseline demographics, hygiene habits, determinants of hygiene, and health status. Sixty survey respondents had microbiological samples taken from eight standardized surfaces in their dormitory environment. Bacterial contamination was assessed using standard quantitative bacterial culture techniques. Additional culturing for coagulase-positive Staphylococcus and coliforms was performed using selective agar. Results: While the vast majority of study participants (n = 461, 92%) believed that hand washing was important for infection prevention, there was a large amount of variation in reported personal hygiene practices. More women than men reported consistent hand washing before preparing food (p = .002) and after using the toilet (p = .001). Environmental hygiene showed similar variability although 73.3% (n = 367) of subjects reported dormitory cleaning at least once per month. Contamination of certain surfaces was common, with at least one third of all bookshelves, desks, refrigerator handles, toilet handles, and bathroom door handles positive for <10 CFU of bacteria per 4 cm2 area. Coagulase-positive Staphylococcus was detected in three participants' rooms (5%) and coliforms were present in six students' rooms (10%). Surface contamination with any bacteria did not vary by frequency of cleaning or frequency of illness (p<.05). Conclusions: Our results suggest that surface contamination, while prevalent, is unrelated to reported hygiene or health in the university setting. Further research into environmental reservoirs of infectious diseases may delineate whether surface decontamination is an effective target of hygiene interventions in this population

Risk factors for hospital-acquired antimicrobial-resistant infection caused by Acinetobacter baumannii

Background Acinetobacter baumannii can cause serious healthcare-associated infections (HAIs) and the incidence is increasing, with many strains now resistant to multiple antibiotic classes. The aims of this study were to examine factors associated with HAIs caused by antimicrobial-resistant as compared with antimicrobial-susceptible strains of A. baumannii and to investigate trends in the incidence of resistance over time. Electronic data from two U.S. hospitals in a large urban healthcare system in over the years 2006–2012 were used for the analysis. Multiple logistic regression was used to explore risk factors for infection with A. baumannii resistant to ampicillin or ampicillin/sulbactam in the bloodstream, urinary tract, and respiratory tract. The Cochran-Armitage trend test was used to explore resistance trends over time. Findings A total of 671 adults with first-time A. baumannii infection were included in the analysis; 302 isolates (45 %) were resistant to ampicillin or ampicillin/sulbactam and 369 (55 %) were susceptible. In the multivariable analysis, significant risk factors included longer length of stay prior to infection (Odds Ratio [OR] = 1.03; 95 % Confidence Interval [CI]: 1.01, 1.04), hospital A versus B (OR = 0.35; 95 % CI: 0.13, 0.93), and antibiotic use prior to infection (OR = 2.88; 95 % CI: 1.02, 8.13). Resistance was more common in respiratory infections (OR = 2.96; 95 % CI: 1.04, 8.44). No trend was found between year of infection and resistance. Conclusions The risk factors we identified are consistent with previous findings, but we found no evidence in this population that resistance to ampicillin or ampicillin/sulbactam was increasing over time

Differences in college students' knowledge, practices, and beliefs about hand hygiene by gender, class standing, and academic major.

a<p>Chi-square test for independence.</p>b<p>Frequencies do not match total N for all questions because not all respondents answered every question.</p><p>Data are percent (n).</p

Microbial flora on dorm room surfaces by type of dorm, frequency of cleaning, and frequency of illness.

a<p>Chi-square test for independence.</p><p>Data are percent (n) of surfaces with >10 colony forming units.</p