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Outbreak of Enterobacter cloacae Related to Understaffing, Overcrowding, and Poor Hygiene Practices

Published online by Cambridge University Press:  02 January 2015

Stephan Harbarth
Affiliation:
Infection Control Program, Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
Philippe Sudre
Affiliation:
Division of Infectious Diseases, Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
Sasi Dharan
Affiliation:
Infection Control Program, Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
Mercedes Cadenas
Affiliation:
Neonatal Intensive Care Unit, Department of Pediatrics, University Hospitals of Geneva, Geneva, Switzerland
Didier Pittet*
Affiliation:
Infection Control Program, Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
*
Infection Control Program, Department of Internal Medicine, Hôpitaux Universitaires de Genève, 1211 Geneva 14, Switzerland

Abstract

Objective:

To determine the cause and mode of transmission of a cluster of infections due to Enterobacter cloacae.

Design and Setting:

Retrospective cohort study in a neonatal intensive-care unit (NICU) from December 1996 to January 1997; environmental and laboratory investigations.

Subjects:

60 infants hospitalized in the NICU during the outbreak period.

Main Outcome Measures:

Odds ratios (OR) linking E cloacae colonization or infection and various exposures. All available E cloacae isolates were typed and characterized by contour-clamped homogenous electric-field electrophoresis to confirm possible cross-transmission.

Results:

Of eight case-patients, two had bacteremia; one, pneumonia; one, soft-tissue infection; and four, respiratory colonization. Infants weighing <2,000 g and born before week 33 of gestation were more likely to become cases (P<.001). Multivariate analysis indicated that the use of multidose vials was independently associated with E cloacae carriage (OR, 16.3; 95% confidence interval [CI95], 1.8-∞ P=011). Molecular studies demonstrated three epidemic clones. Cross-transmission was facilitated by understaffing and overcrowding (up to 25 neonates in a unit designed for 15), with an increased risk of E cloacae carriage during the outbreak compared to periods without understaffing and overcrowding (relative risk, 5.97; CI95, 2.2-16.4). Concurrent observation of healthcare worker (HCW) handwashing practices indicated poor compliance. The outbreak was terminated after decrease of work load, increase of hand antisepsis, and reinforcement of single-dose medication.

Conclusions:

Several factors caused and aggravated this outbreak: (1) introduction of E cloacae into the NICU, likely by two previously colonized infants; (2) further transmission by HCWs' hands, facilitated by substantial overcrowding and understaffing in the unit; (3) possible contamination of multidose vials with E cloacae. Overcrowding and understaffing in periods of increased work load may result in outbreaks of nosocomial infections and should be avoided.

Type
Orginal Articles
Copyright
Copyright © The Society for Healthcare Epidemiology of America 1999

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References

1. Sanders, WE Jr, Sanders, CC. Enterobacter spp: pathogens poised to flourish at the turn of the century. Clin Microbiol Rev 1997;10:220241.Google Scholar
2. Acolet, D, Ahmet, Z, Houang, E, Hurley, R, Kaufmann, ME. Enterobacter cloacae in a neonatal intensive care unit: account of an outbreak and its relationship to use of third generation cephalosporins. J Hosp Infect 1994;28:273286.Google Scholar
3. Andersen, BM, Sorlie, D, Hotvedt, R, Almdahl, SM, Olafsen, K, George, R, et al. Multiply beta-lactam resistant Enterobacter cloacae infections linked to the environmental flora in a unit for cardiothoracic and vascular surgery. Scand J Infect Dis 1989;21:181191.CrossRefGoogle Scholar
4. Mayhall, CG, Lamb, VA, Gayle, WE Jr, Haynes, BW Jr. Enterobacter cloacae septicemia in a burn center: epidemiology and control of an outbreak. J Infect Dis 1979;139:166171.CrossRefGoogle Scholar
5. Verweij, PE, van Belkum, A, Melchers, WJ, Voss, A, Hoogkamp Korstanje, JA, Meis, JF. Interrepeat fingerprinting of third-generation cephalosporin-resistant Enterobacter cloacae isolated during an outbreak in a neonatal intensive care unit. Infect Control Hosp Epidemiol 1995;16:2529.CrossRefGoogle Scholar
6. Matsaniotis, NS, Syriopoulou, VP, Theodoridou, MC, Tzanetou, KG, Mostrou, Gl. Enterobacter sepsis in infants and children due to contaminated intravenous fluids. Infect Control 1984;5:471477.CrossRefGoogle ScholarPubMed
7. Jarvis, WR, Highsmith, AK, Allen, JR, Haley, RW. Polymicrobial bacteremia associated with lipid emulsion in a neonatal intensive care unit. Pediatr Infect Dis 1983;2:203208.CrossRefGoogle Scholar
8. Thomas, A, Lalitha, MK, Jesudason, MV, John, S. Transducer related Enterobacter cloacae sepsis in post-operative cardiothoracic patients. J Hosp Infect 1993;25:211214.CrossRefGoogle ScholarPubMed
9. Flynn, DM, Weinstein, RA, Nathan, C, Gaston, MA, Kabins, S. Patients' endogenous flora as the source of “nosocomial” Enterobacter in cardiac surgery. J Infect Dis 1987;156:363368.Google Scholar
10. Goldmann, DA, Leclair, J, Macone, A Bacterial colonization of neonates admitted to an intensive care environment. J Pediatr 1978;93:288293.CrossRefGoogle Scholar
11. Leonard, EM, Van Saene, HK, Shears, P, Walker, J, Tam, P. Pathogenesis of colonization and infection in a neonatal surgical unit Crit Care Med 1990;18:264269.Google Scholar
12. Burman, LG, Berglund, B, Huovinen, P, Tulius, K. Effect of ampicillin versus cefuroxime on the emergence of beta-lactam resistance in faecal Enterobacter cloacae isolates from neonates. J Antimicrob Chemother 1993;31:111116.Google Scholar
13. Bonadio, WA, Margolis, D, Tovar, M. Enterobacter cloacae bacteremia in children: a review of 30 cases in 12 years. Clin Pediatr (Phila) 1991;30:310313.CrossRefGoogle Scholar
14. Andresen, J, Asmar, BI, Dajani, AS. Increasing Enterobacter bacteremia in pediatric patients. Pediatr Infect Dis J 1994;13:787792.CrossRefGoogle ScholarPubMed
15. Garner, JS, Jarvis, WR, Emori, TG, Horan, TC, Hughes, JM. CDC definitions for nosocomial infections. Am J Infect Control 1988;16:128140.CrossRefGoogle ScholarPubMed
16. Lambert, P, Major, L, Saint-Onge, E, Saulnier, D, Tilquin, C, Vanderstraeten, G. L'intégration de la planification des soins et de la mesure de la charge de travail au service des démarches scientifiques du soignant et du gestionnaire: la méthode PRN. In: Thibault, C, ed. Les Systèmes de Mesure de la Charge de Travail en Soins Infirmiers. Montréal, Quebec, Canada: Association des Hôpitaux du Québec; 1990:189194.Google Scholar
17. O'Brien-Pallas, L, Cockerill, R, Leatt, P. Different systems, different costs? An examination of the comparability of workload measurement systems. J Nurs Adm 1992;22:1722.Google Scholar
18. Hernandez, CA, O'Brien-Pallas, LL, Validity and reliability of nursing workload measurement systems: review of validity and reliability theory. Can J Nurs Adm 1996;9:3250.Google Scholar
19. O'Brien-Pallas, L, Irvine, D, Peereboom, E, Murray, M. Measuring nursing workload: understanding the variability. Nurs Econ 1997;15:171182.Google ScholarPubMed
20. Pittet, D, Mourouga, P, Perneger, TV. Compliance with handwashing in a teaching hospital. Infection Control Program. Ann Intern Med 1999;130:126130.CrossRefGoogle Scholar
21. National Committee for Clinical Laboratory Standards. Performance Standards for Antimicrobial Disk Susceptibility. M2 – A5 ed. Villanova, PA, NCCLS; 1993.Google Scholar
22. Smith, CL, Cantor, CR. Purification, specific fragmentation, and separation of large DNA molecules. Methods Enzymol 1987;155:449467.Google Scholar
23. Bingen, E. Applications of molecular methods to epidemiologic investigations of nosocomial infections in a pediatric hospital. Infect Control Hosp Epidemiol 1994;15:488493.CrossRefGoogle Scholar
24. Tenover, FC, Arbeit, RD, Goering, RV. How to select and interpret molecular strain typing methods for epidemiological studies of bacterial infections: a review of healthcare epidemiologists. Infect Control Hosp Epidemiol 1997;18:426439.CrossRefGoogle ScholarPubMed
25. Hirji, KF, Menta, CR, Patel, NR. Exact inference for matched case-control studies. Biometrics 1988;44:803814.CrossRefGoogle ScholarPubMed
26. Jarvis, WR, Handwashing—the Semmelweis lesson forgotten? Lancet 1994;344:13111312.CrossRefGoogle ScholarPubMed
27. Huebner, J, Pier, GB, Maslow, JN, Muller, E, Shiro, H, Parent, M, et al. Endemie nosocomial transmission of Staphylococcus epidermidis bacteremia isolates in a neonatal intensive care unit over 10 years. J Infect Dis 1994;169:526531.Google Scholar
28. Eisenach, KD, Reber, RM, Eitzman, DV, Baer, H. Nosocomial infections due to kanamycin-resistant, (R)-factor carrying enteric organisms in an intensive care nursery. Pediatrics 1972;50:395402.CrossRefGoogle Scholar
29. Coudron, PE, Mayhall, CG, Facklam, RR, Spadora, AC, Lamb, VA, Lybrand, MR, et al. Streptococcus faecium outbreak in a neonatal intensive care unit. J Clin Microbiol 1984;20:10441048.CrossRefGoogle Scholar
30. Noya, FJ, Rench, MA, Metzger, TG, Colman, G, Naidoo, J, Baker, CJ. Unusual occurrence of an epidemic of type Ib/c group B streptococcal sepsis in a neonatal intensive care unit. J Infect Dis 1987;155:11351144.CrossRefGoogle Scholar
31. Finkelstein, R, Reinhertz, G, Hashman, N, Merzbach, D. Outbreak of Candida tropicalis fungemia in a neonatal intensive care unit. Infect Control Hosp Epidemiol 1993;14:587590.Google Scholar
32. Chang, HJ, Miller, HL, Watkins, N, Arduino, MJ, Ashford, DA, Midgley, G, et al. An epidemic of Malassezia pachydermatis in an intensive care nursery associated with colonization of health care workers' pet dogs. N Engl J Med 1998;338:706711.CrossRefGoogle Scholar
33. Simmons, B, Bryant, J, Neiman, K, Spencer, L, Arheart, K. The role of handwashing in prevention of endemic intensive care unit infections. Infect Control Hosp Epidemiol 1990;11:589594.CrossRefGoogle ScholarPubMed
34. Powell, J, Bureau, MA, Pare, C, Gaildry, ML, Cabana, D, Patriquin, H. Necrotizing enterocolitis. Epidemic following an outbreak of Enterobacter cloacae type 3305573 in a neonatal intensive care unit. Am J Dis Child 1980;134:11521154.Google Scholar
35. Pittet, D. Nosocomial bloodstream infections. In: Wenzel, RP, ed. Prevention and Control of Nosocomial Infections. 3rd ed. Boston, MA: Williams & Wilkins; 1997:712769.Google Scholar
36. McDonald, LC, Walker, M, Carson, L, Arduino, M, Aguero, SM, Gomez, P, et al. Outbreak of Acinetobacter spp bloodstream infections in a nursery associated with contaminated aerosols and air conditioners. Pediatr Infect Dis J 1998;17:716722.Google Scholar
37. Moore, DL. Newborn nursery and neonatal intensive care unit. In: Olmsted, RN, ed. APIO. Infection Control and Applied Epidemiology. Principles and Practice. 1st ed. St. Louis, MO: Mosby; 1996:section 94, pages 114.Google Scholar
38. Haley, RW, Bregman, D. The role of understaffing and overcrowding in recurrent outbreaks of staphylococcal infection in a neonatal special-care unit J Infect Dis 1982;145:875885.CrossRefGoogle Scholar
39. Haley, RW, Cushion, NB, Tenover, FC, Bannerman, TL, Dryer, D, Ross, J, et al. Eradication of endemic methicillin-resistant Staphylococcus aureus infections from a neonatal intensive care unit. J Infect Dis 1995;171:614624.CrossRefGoogle ScholarPubMed
40. Fridkin, SK, Pear, SM, Williamson, T, Galgiani, JN, Jarvis, WR. The role of understaffing in central venous catheter-associated bloodstream infections. Infect Control Hosp Epidemiol 1996;17:150158.Google Scholar
41. Archibald, LK, Manning, ML, Bell, LM, Banerjee, S, Jarvis, WR, Patient density, nurse-to-patient ratio and nosocomial infection risk in a pediatric cardiac intensive care unit. Pediatr Infect Dis J 1997;16:10451048.Google Scholar
42. Farr, BM. Understaffing: a risk factor for infection in the era of down sizing? Infect Control Hosp Epidemiol 1996;17:147149.Google Scholar