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Multidrug-Resistant Gram-Negative Bacteria in a Long-Term Care Facility: Prevalence and Risk Factors

OBJECTIVES: To quantify the prevalence, risk factors, and mode of transmission associated with colonization by multidrug‐resistant gram‐negative bacteria (MDRGN) in the long‐term care (LTC) setting.

The Emerging Threat of Multidrug-Resistant Gram-Negative Organisms in Long-Term Care Facilities

Background Infections caused by antimicrobial-resistant bacteria are associated with substantial morbidity and mortality. Residents of long-term care facilities (LTCF) are among the main reservoirs of antimicrobial-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Multidrug-resistant gram-negative organisms (MDRGN) are emerging as important pathogens among LTCF residents. Data on the clinical epidemiology of MDRGN, especially in comparison to VRE and MRSA, are limited. Methods All clinical cultures collected from residents of a 750-bed LTCF for a period of 2 years were analyzed for the presence of MDRGN, VRE, and MRSA. Multidrug resistance among gram-negative bacteria was defined as resistance to three or more antimicrobials or antimicrobial groups including extended-spectrum penicillins (ampicillin/sulbactam or piperacillin/tazobactam), cephalosporins (cefazolin or ceftriaxone), gentamicin, ciprofloxacin, and trimethoprim-sulfamethoxazole (TMP/SMX). Results A total of 1,661 clinical cultures were included in the analysis. MDRGN were recovered from 180 (10.8%) cultures, MRSA from 104 (6.3%), and VRE from 11 (0.6%). MDRGN were isolated more frequently than MRSA or VRE throughout the study period. The prevalence of MDRGN increased significantly from 7% in 2003 to 13% in 2005 (p = .001). More than 80% of MDRGN isolates were resistant to ciprofloxacin, TMP/SMX, and ampicillin/sulbactam. Resistance to three, four, and five or more antimicrobials were identified among 122 (67.8%), 47 (26.1%), and 11 (6.1%) MDRGN isolates, respectively. Conclusions Rates of MDRGN exceeded those of MRSA and VRE and increased throughout the study period. Resistance to multiple, commonly prescribed antimicrobials among MDRGN raises concerns about therapeutic options available to treat MDRGN infections among LTCF residents.

Multidrug-resistant gram-negative bacteria among patients who require chronic hemodialysis.

BACKGROUND AND OBJECTIVES Multidrug-resistant gram-negative bacteria are rapidly spreading throughout the world. The epidemiology of multidrug-resistant gram-negative bacteria in patients who require chronic hemodialysis has not been previously studied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A prospective cohort study of an outpatient hemodialysis unit was conducted. Serial surveillance cultures for multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus were collected from patients who were undergoing chronic hemodialysis. RESULTS Nineteen (28%) of the 67 enrolled patients were colonized with one or more antimicrobial-resistant bacteria at study enrollment. Eleven (16%), nine (13%), and three (5%) patients were colonized with multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus, respectively. Independent risk factors associated with harboring multidrug-resistant gram-negative bacteria at enrollment were residence in a long-term care facility and antibiotic exposure for > or = 7 d in the previous 3 mo. Twenty-two (40%) of 55 patients who had follow-up cultures acquired at least one antimicrobial-resistant bacterium. A total of 20, 15, and 13% of patients acquired multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus, respectively. Antibiotic exposure was the only independent risk factor for multidrug-resistant gram-negative bacteria acquisition. Endogenous multidrug-resistant gram-negative bacteria acquisition was detected among 69% of acquired multidrug-resistant gram-negative bacterial strains. CONCLUSIONS The prevalence and acquisition of multidrug-resistant gram-negative bacteria surpassed that of vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus. Endogenous acquisition, as opposed to patient-to-patient spread, was the predominant mechanism of acquisition. Residence in a long-term care facility and antibiotic exposure may be important factors promoting the spread of multidrug-resistant gram-negative bacteria among this patient population.

Influx of Multidrug‐Resistant, Gram‐Negative Bacteria in the Hospital Setting and the Role of Elderly Patients With Bacterial Bloodstream Infection

BACKGROUND Multidrug-resistant (MDR) gram-negative bacteria are reported increasingly frequently among isolates recovered from elderly patients. The clinical epidemiology of bloodstream infection (BSI) due to MDR gram-negative bacteria among elderly patients is unknown. OBJECTIVE To characterize the clinical epidemiology of BSI due to MDR gram-negative bacteria among elderly patients at hospital admission in an effort to provide a greater understanding of these serious infections and ultimately to improve patient outcomes. DESIGN Case-control study. SETTING Tertiary care hospital in Boston, Massachusetts. PATIENTS Patients 65 years of age and older. METHODS From 1999 to 2007, computerized medical records were reviewed for BSI due to MDR gram-negative bacteria within 48 hours of hospital admission. Risk factors for BSI due to these bacteria were identified. RESULTS MDR gram-negative bacteria were recovered from 61 (8%) of 724 elderly patients with BSI caused by gram-negative bacteria. Over the 8 1/2-year study period, the percentage of MDR gram-negative bacteria among bloodstream isolates increased from 2 (1%) of 199 to 34 (16%) of 216. Empiric therapy was ineffective for 38 (63%) of 60 patients with BSI caused by MDR gram-negative bacteria. The variables independently associated with BSI due to these bacteria were as follows: residency in a long-term care facility (odds ratio [OR], 4.9 [95% confidence interval {CI} 1.6-14.9]; P= .006), presence of an invasive device (OR, 6.0 [95% CI, 1.5-23.5]; P= .01), severe sepsis (OR, 7.9 [95% CI, 1.7-37.1]; P= .009), and delayed initiation of effective therapy (OR, 12.8 [95% CI, 3.9-41.1]; P= .001). CONCLUSION The 16-fold increase in BSI due to MDR gram-negative bacteria at hospital admission among elderly patients, especially among those who resided in long-term care facilities prior to admission, contributes further to the expanding body of evidence that these patients are the main reservoirs of MDR gram-negative bacteria. Given their contribution to the influx of antimicrobial-resistant bacteria in the hospital setting, infection control interventions that target this high-risk group need to be considered.

Effect of influenza on functional decline

To examine the relationship between influenza and activity of daily living (ADL) decline and other clinical indicators in nursing home (NH) residents.

The clinical impact of multidrug-resistant gram-negative bacilli in the management of septic shock

Multi-antibiotic drug-resistant (MDR) gram-negative bacilli are becoming a major threat to the standard care of septic patients. Empiric antimicrobial drug regimens to cover likely bacterial pathogens have to be altered in keeping with the spread of MDR pathogens in the health care setting and in the community. Reliable antibiotics for broad spectrum coverage for sepsis such as extended spectrum β-lactam antibiotics, carbapenems, and fluoroquinolones can no longer be counted upon to provide activity against a range of common, virulent pathogens that cause sepsis. In some regions of Asia, South America, and Eastern Europe in particular, MDR pathogens have become a major concern, necessitating the use of potentially toxic and costly antibiotic combinations as initial antibiotic therapy for septic shock. In this brief review, we will focus on the emergence of MDR gram-negative pathogens, resistance mechanisms, and suggest some management and prevention strategies against MDR pathogens.

Treatment for infections with carbapenem- resistant Enterobacteriaceae: what options do we still have?

The global spread of carbapenem-resistant Enterobacteriaceae (CRE) is increasingly becoming a major challenge in clinical and public health settings. To date, the treatment for serious CRE infections remains difficult. The intelligent use of antimicrobials and effective infection control strategies is crucial to prevent further CRE spread. Early consultation with experts in the treatment of infections with multidrug-resistant organisms is valuable in patient management. This brief review will focus on the current, yet limited, treatment options for CRE infections.

Estimating the Effect of Influenza Vaccination on Nursing Home Residents’ Morbidity and Mortality

To estimate the effect of influenza vaccination on hospitalization and mortality in nursing home (NH) residents.

Risk of Clostridium difficile Infection in Hematology-Oncology Patients Colonized With Toxigenic C. difficile

The prevalence of colonization with toxigenic Clostridium difficile among patients with hematological malignancies and/or bone marrow transplant at admission to a 566-bed academic medical care center was 9.3%, and 13.3% of colonized patients developed symptomatic disease during hospitalization. This population may benefit from targeted C. difficile infection control interventions. Infect Control Hosp Epidemiol 2017;38:718-720.

Healthcare Workers’ Hands and Clostridium difficile Spores: Making Progress?

Affiliations: 1. Division of Infectious Diseases, Memorial Hospital of Rhode Island, Warren Alpert Medical School at Brown University, Pawtucket, Rhode Island; 2. Healthcentric Advisors, Providence, Rhode Island; and Department of Health Services, Policy, and Practice, Warren Alpert Medical School at Brown University, Providence, Rhode Island. Received October 1, 2013; accepted October 2, 2013; electronically published November 26, 2013. 2013 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2014/3501-0004