Colonization of residents and staff of a long-term-care facility and adjacent acute-care hospital geriatric unit by multiresistant bacteria

• Published in: Clinical microbiology and infection Vol. 16; no. 7; pp. 934 - 944
• Main Authors: March, A., Aschbacher, R., Dhanji, H., Livermore, D.M., Böttcher, A., Sleghel, F., Maggi, S., Noale, M., Larcher, C., Woodford, N.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-07-2010; Blackwell Publishing Ltd; Wiley-Blackwell; Elsevier Limited
• Subjects: Agar; Age; AmpC; Antibiotics; b-Lactamase; Bacteria; Bacteria - drug effects; Bacteria - isolation & purification; beta -Lactamase; Biological and medical sciences; Chronic obstructive pulmonary disease; Colonization; Cross Infection - diagnosis; Cross Infection - epidemiology; Cross Infection - microbiology; Data processing; Dementia disorders; Demography; Drug resistance; Drug Resistance, Multiple, Bacterial; Electrophoresis, Gel, Pulsed-Field; Enterobacteriaceae; Enterobacteriaceae - drug effects; Enterobacteriaceae - isolation & purification; Enterococcus - drug effects; Enterococcus - isolation & purification; Escherichia coli; extended-spectrum β-lactamases; Geriatrics; Health Services for the Aged; Hospital Units; Hospitals; Humans; Infectious diseases; Inguinal Canal - microbiology; Insertion sequences; Italy; Long-Term Care; long-term-care facility; Medical research; Medical sciences; Metallo- beta -lactamase; Metallo-b-lactamase; metallo-β-lactamase; Methicillin-Resistant Staphylococcus aureus - drug effects; Methicillin-Resistant Staphylococcus aureus - isolation & purification; MRSA; Nose - microbiology; Oropharynx - microbiology; Patients; Personnel, Hospital; Plasmids; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Pulsed-field gel electrophoresis; Rectum; Rectum - microbiology; Restriction fragment length polymorphism; risk factor analysis; Risk Factors; screening; Staphylococcus aureus; Staphylococcus infections; Urine; Urine - microbiology; Vancomycin Resistance; VRE; Italy; AmpC; screening; extended-spectrum β-lactamases; long-term-care facility; MRSA; VRE; metallo-β-lactamase; risk factor analysis; Multiple resistance; Bacteria; Micrococcales; Micrococcaceae; Hospital; Staphylococcus aureus; Enterococcus; Health staff; Acute; Risk analysis; Medical screening; Infection; Streptococcaceae; Risk factor; Homes for the aged; Colonization; Geriatrics
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2009.03024.x

Long-term-care facilities (LTCFs) are reservoirs of resistant bacteria. We undertook a point-prevalence survey and risk factor analysis for specific resistance types among residents and staff of a Bolzano LTCF and among geriatric unit patients in the associated acute-care hospital. Urine samples and rectal, inguinal, oropharyngeal and nasal swabs were plated on chromogenic agar; isolates were typed by pulsed-field gel electrophoresis; resistance genes and links to insertion sequences were sought by PCR; plasmids were analysed by PCR, restriction fragment length polymorphism and incompatibility grouping. Demographic data were collected. Of the LTCF residents, 74.8% were colonized with ≥1 resistant organism, 64% with extended-spectrum β-lactamase (ESBL) producers, 38.7% with methicillin-resistant Staphylococcus aureus (MRSA), 6.3% with metallo-β-lactamase (MBL) producers, and 2.7% with vancomycin-resistant enterococci. Corresponding rates for LTCF staff were 27.5%, 14.5%, 14.5%, 1.5% and 0%, respectively. Colonization frequencies for geriatric unit patients were lower than for those in the LTCF. Both clonal spread and plasmid transfer were implicated in the dissemination of MBL producers that harboured IncN plasmids bearing blaVIM-1, qnrS, and blaSHV-12. Most (44/45) ESBL-producing Escherichia coli isolates had blaCTX-M genes of group 1; a few had blaCTX-M genes of group 9 or blaSHV-5; those with blaCTX-M-15 or blaSHV-5 were clonal. Risk factors for colonization of LTCF residents with resistant bacteria included age ≥86 years, antibiotic treatment in the previous 3 months, indwelling devices, chronic obstructive pulmonary disease, physical disability, and the particular LTCF unit; those for geriatric unit patients were age and dementia. In conclusion, ESBL-producing and MBL-producing Enterobacteriaceae and MRSA were prevalent among the LTCF residents and staff, but less so in the hospital geriatric unit. Education of LTCF employees and better infection control are proposed to minimize the spread of resistant bacteria in the facility.