Antibiotic-resistant organisms among long-term care facility residents on admission to an inpatient geriatrics unit: Retrospective and prospective surveillance

Prevalence and Risk Factors for Multidrug-Resistant Organisms Colonization in Long-Term Care Facilities Around the World: A Review

Elderly people confined to chronic care facilities face an increased risk of acquiring infections by multidrug-resistant organisms (MDROs). This review presents the current knowledge of the prevalence and risk factors for colonization by MDROs in long-term care facilities (LTCF), thereby providing a useful reference to establish objectives for implementing successful antimicrobial stewardship programs (ASPs). We searched in PubMed and Scopus for studies examining the prevalence of MDROs and/or risk factors for the acquisition of MDROs in LTCF. One hundred and thirty-four studies published from 1987 to 2020 were included. The prevalence of MDROs in LTCF varies between the different continents, where Asia reported the highest prevalence of extended-spectrum ß-lactamase (ESBL) Enterobacterales (71.6%), carbapenem resistant (CR) Enterobacterales (6.9%) and methicillin-resistant Staphylococcus aureus (MRSA) (25.6%) and North America the highest prevalence to MDR Pseudomonas aeruginosa (5.4%), MDR Acinetobacter baumannii (15.0%), vancomycin-resistant Enterococcus spp. (VRE) (4.0%), and Clostridioides difficile (26.1%). Furthermore, MDRO prevalence has experienced changes over time, with increases in MDR P. aeruginosa and extended spectrum ß-lactamase producing Enterobacterales observed starting in 2015 and decreases of CR Enterobacterales, MDR A. baumannii, VRE, MRSA and C. difficile. Several risk factors have been found, such as male sex, chronic wounds, the use of medical devices, and previous antibiotic use. The last of these aspects represents one of the most important modifiable factors for reducing colonization with MDROs through implementing ASPs in LTCF.

Nursing Home-Acquired Bloodstream Infection

Objectives:

This article reviews published studies of nursing home-acquired BSI in North America to determine whether there have been changes in the epidemiology of this infection in the past 20 years and to define indications for blood cultures in the nursing home setting.

Methods:

A Medline search was conducted for the period from 1980 to August 2003.

Results:

Seven studies of nursing home-acquired BSI were identified. The incidence of nursing home-acquired BSI was low (0.3 episode per 1,000 resident care-days). Sources of BSI changed little during the past two decades, with urinary tract infection representing approximately 50% of the episodes. The bacteriology also did not change substantially during the past 20 years; gram-negative bacilli were isolated in approximately 50% of the episodes and Escherichia coli was the most commonly isolated organism. In the most recent study, covering the period 1997-2000, resistance to fluoroquinolones and broad-spectrum penicillins and cephalosporins was uncommon among gram-negative blood isolates; MRSA was the most common resistant organism causing nursing home-acquired BSI. Case-fatality rates changed little during the past 20 years; urinary tract infection was associated with the lowest mortality and pneumonia had the highest case-fatality rate.

Conclusion:

There has been little change in the epidemiology of nursing home-acquired BSI in the past 20 years. Given the low incidence of BSI and the low overall yield of positive results of blood cultures (probably ≤ 6%), there is currently no support for the routine use of blood cultures in the nursing home setting.

Comparison of the bacterial isolates and antibiotic resistance patterns of elderly nursing home and general community patients

BACKGROUND

Nursing home-acquired infections may differ from general community-acquired infections in bacteriology and antibiotic resistance. However, there are currently limited data on this topic in the Australian setting.

AIMS

To compare bacterial isolates and antibiotic resistance patterns, from pathology specimens of nursing home and community patients, and to comment on the suitability of empiric antibiotic guidelines for nursing home-acquired infection.

METHODS

This was a retrospective cohort study of patients, aged ≥ 65 years, who resided in either nursing homes or the general community. Patients with a hospital admission in the previous 28 days were excluded. Positive specimen cultures, collected between July 2003 and June 2008 in the Emergency Department and Outpatient Clinics of the Austin Hospital (Melbourne), were examined. The main outcome measures were the bacterial isolates, and their antibiotic resistance patterns, of patients from nursing homes and the general community.

RESULTS

Specimens of blood (638), sputum (425), urine (4044) and wound cultures (785) were examined. The bacteriology of blood culture isolates did not differ between the two groups (P= 0.3). However, the bacteriology of sputum, urine and wound cultures differed significantly between the groups (P= 0.025, P < 0.001, P= 0.004 respectively). There were also higher proportions of antibiotic resistance among some bacteria in nursing home patients, especially methicillin resistance among Staphylococcus aureus isolates across all specimen types, and resistance to several empiric antibiotics among Enterobacteriaceae isolates in urine cultures.

CONCLUSION

Empiric antibiotic guidelines appear adequate to treat nursing home-acquired septicaemia and pneumonia. However, guidelines for urinary tract infections and wound infections may need to be refined.

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic

Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

Inflammation and the host response to injury, a large-scale collaborative project: patient-oriented research core--standard operating procedures for clinical care VII--Guidelines for antibiotic administration in severely injured patients

When the clinical decision to treat a critically ill patient with antibiotics has been made, one must attempt to identify the site of infection based on clinical signs and symptoms, laboratory or diagnostic radiology studies. Identification of site requires, examination of patient, inspection of all wounds, chest radiograph, and calculation of clinical pulmonary infection score if ventilated, obtaining blood cultures, urinalysis, and line change if clinical suspicion of central venous catheter (CVC) source. If it is impossible to identify site, obtain cultures from all accessible suspected sites and initiate empiric, broad spectrum antibiotics. If likely site can be identified answer these questions: Is intra-abdominal site suspected? Is pulmonary source of infection suspected? Is skin, skin structure or soft tissue site suspected? If yes, does the patient have clinical signs suspicion for necrotizing soft tissue infection (NSTI)? Is a CVC infection suspected? Risk factors for more complicated infections are discussed and specific antibiotic recommendations are provided for each type and severity of clinical infection. Decision to continue, discontinue and/or alter antibiotic/antimicrobial treatment should be based on the clinical response to treatment, diagnostic or interventional findings, and culture and sensitivity data, bearing in mind that not all patients with infections will have positive cultures because of limitations of specimen handling, microbiology laboratory variations, time between specimen acquisition and culture, or presence of effective antibiotics at the time that specimens were obtained. It should also be noted that not all patients with increased temperature/WBC have an infection. Discontinuation of antibiotics is appropriate if cultures and other diagnostic studies are negative.

Post-ICU mechanical ventilation at 23 long-term care hospitals: a multicenter outcomes study

STUDY OBJECTIVES

This multicenter study was undertaken to characterize the population of ventilator-dependent patients admitted to long-term care hospitals (LTCHs) with weaning programs, and to report treatments, complications, weaning outcome, discharge disposition, and survival in these patients.

DESIGN

Observational study with concurrent data collection.

SETTING

Twenty-three LTCHs in the United States.

PATIENTS

Consecutive ventilator-dependent patients admitted over a 1-year period: March 1, 2002, to February 28, 2003.

RESULTS

A total of 1,419 patients were enrolled in the Ventilation Outcomes Study. Median age of patients was 71.8 years (range, 18 to 97.7 years). Patients averaged 6.9 procedures and treatments during the LTCH hospitalization; median length of stay was 40 days (range, 1 to 365 days). Seven of the 10 most frequent complications treated at the LTCH were infections; congestive heart failure and diabetes mellitus were the most common comorbidities requiring treatment. Outcomes of weaning attempts, scored at LTCH discharge, were 54.1% weaned, 20.9% ventilator dependent, and 25.0% deceased. Median time to wean (n = 766) was 15 days (range, 7 to 30 days). Discharge disposition included 28.8% to home, 49.2% to rehabilitation and extended-care facilities, and 19.5% to short-stay acute hospitals. Nearly one third of patients were known to be alive 12 months after admission to the LTCH.

CONCLUSIONS

Patients admitted to LTCHs for weaning attempts were elderly, with acute-on-chronic diseases, and continued to require considerable medical interventions and treatments. The frequency and type of complications were not surprising following prolonged and aggressive ICU interventions. In the continuum of critical care medicine, more than half of ventilator-dependent survivors of catastrophic illness transferred from the ICU were successfully weaned from prolonged mechanical ventilation in the setting of an LTCH.

Increased mortality among elderly patients with meticillin-resistant Staphylococcus aureus bacteraemia

Despite the high prevalence of meticillin-resistant Staphylococcus aureus (MRSA) infections among the elderly, outcomes of nosocomial MRSA bloodstream infections (BSI) for this patient population have not been fully examined. We performed a case-control study to compare outcomes of hospital-acquired MRSA BSI among patients >/=65 years of age (cases) with those younger than 65 years of age (controls). In a 430-bed tertiary-care teaching hospital, 100 hospitalized patients >/=18 years of age with S. aureus BSI were included in the study. Measurements obtained were: comorbidities, severity of illness at presentation, antibiotic therapy, haematogenous complications and mortality. Overall mortality was significantly higher among cases than controls [36% vs 12%; odds ratio (OR) 4.1, 95% confidence interval (CI) 1.4-14, P<0.01]. A pulmonary source was identified more frequently among elderly patients compared with younger controls (34% vs 16%; OR 2.7, 95%CI 1.1-8.1, P=0.04). On logistic regression, the following variables were independently associated with MRSA BSI among elderly patients: admission to a medical ward (OR 3.1, 95%CI 1.3-7.6, P=0.02), non-central-venous-catheter-related BSI (OR 3, 95%CI 1.2-7.6, P=0.02) and death (OR 3.7, 95%CI 1.3-11, P=0.02). Among patients who received vancomycin, more cases were treated with a reduced dose of vancomycin due to renal insufficiency compared with controls (64% vs 31%; OR 4, 95%CI 2-9, P=0.01). These data suggest that MRSA BSI is associated with significant mortality among the elderly population. Preventing MRSA acquisition among this patient population is of paramount importance.

Antimicrobial Management of Complicated Skin and Skin Structure Infections in the Era of Emerging Resistance

BACKGROUND

Complicated skin and skin structure infections (cSSSIs) are among the most common infections treated in the hospital setting. The mainstays of treatment continue to be antimicrobial therapy combined with appropriate surgical intervention. Due to increasing resistance among pathogens commonly implicated in cSSSIs, the objectives of this review were to describe the potential pathogens causing skin infections, the implications of resistance to currently used drug therapy, and the role of new antibiotics with activity for pathogens causing cSSSIs.

METHODS

Relevant information from the primary literature and review articles were identified through a MEDLINE search of the medical literature (1980 to the present) using the terms abscess, wound infection, skin and skin structure infection, antibiotics, resistance, quinupristin- dalfopristin, linezolid, daptomycin, tigecycline, oritavancin, and dalbavancin. Meeting posters and slides were identified from the Interscience Conference of Antimicrobial Agents and Chemotherapy (1998-2004) for supplemental data.

RESULTS

The most commonly implicated pathogens in cSSSIs include gram-positive bacteria, specifically Staphylococcus aureus. Gram-negative and mixed organisms are additionally encountered in serious cSSSI. Antimicrobial resistance among both gram-positive and gramnegative bacteria has increased significantly during the last decade, with methicillin resistance among S. aureus approaching 60% in hospitals and becoming more frequent in the community as well. As a result, resistance is the driving factor for treatment failure and rising costs for infection management. Few antimicrobial agents are available currently to treat resistant bacteria in cSSSIs; vancomycin is currently the drug of choice against resistant grampositive cocci; however, resistance to this agent has appeared in enterococci and S. aureus. Several new antibiotics such as linezolid and daptomycin are now available for the management of cSSSIs. Other agents such as tigecycline are under investigation and should be available soon to increase treatment options for cSSSIs caused by resistant bacteria.

CONCLUSIONS

Although the resistance of cSSSI pathogens is problematic, new antibiotics with broad-spectrum activity against resistant gram-positive and gram-negative bacteria are promising for the management of severe cSSSIs.

Prevalence and risk factors of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an Israeli long-term care facility

The purpose of this study was to ascertain the prevalence of extended-spectrum beta-lactamases (ESBLs) among Escherichia coli and Klebsiella pneumoniae strains obtained from urine samples of residents of a long-term care facility and to determine the risk factors for acquisition of ESBL-producing strains. All urine samples collected from January 2003 to October 2003 that were positive for E. coli or K. pneumoniae were tested for the presence of ESBL. Records of patients with ESBL-positive (ESBL-P) samples were analyzed for clinical and demographic data. The records of a matched control group of patients whose urine samples were positive for E. coli or K. pneumoniae but were ESBL-negative (ESBL-N) were also analyzed. The overall rate of ESBLs among the E. coli and K. pneumoniae samples was 25.6%. Of 350 urine samples that grew E. coli, 77 (22%) were positive for ESBL; 34 of 84 (40.5%) samples that grew K. pneumoniae were ESBL-P. Male sex, treatment in the subacute care unit, recent antimicrobial treatment, pressure sores, (percutaneous endoscopic gastrostomy) PEG tube, anemia, hypoalbuminemia, permanent urinary catheter, and any recent invasive procedure were all associated with ESBL-P bacteria in the univariate analysis. The multivariate analysis revealed three independent risk factors for the presence of an ESBL-producing strain: anemia, permanent urinary catheter, and previous antibiotic use. Fluoroquinolones were most strongly associated with the development of ESBL-producing bacteria. The prevalence of ESBL-producing E. coli and K. pneumoniae in the long-term care facility investigated was unexpectedly high and corroborates the notion that long-term care facilities could be important reservoirs of resistant bacteria. Identification of the risk factors for ESBLs is the first step in formulating an effective strategy to curtail the spread of ESBL resistance in long-term care facilities.

Antibiotic-resistant gram-negative bacteria in hospitalized children

Antibiotic-resistant Gram-negative bacilli are a prominent and growing problem among hospitalized children. Epidemics caused by these organisms have been implicated in many outbreaks in children's hospitals, primarily in neonatal intensive care units. These epidemics are characterized by efficient patient-to-patient transmission of the outbreak clone via the hands of caregivers and through exposure of contaminated inanimate sources. The epidemiology of these resistant organisms in pediatric hospitals during endemic periods is more complex. The isolates cultured from hospitalized individuals in the absence of an outbreak usually are unique to each individual and are derived from the patient's endogenous flora or other disparate sources. As in adults, chronic care facilities for children represent significant reservoirs of antibiotic-resistant bacilli that are circulated back into the acute care hospital environment when the child becomes ill.

Methicillin-resistant Staphylococcus aureus and infection control for restorative dental treatment in nursing homes

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in nursing home residents now averages 20-35%. This includes both numerous asymptomatic mostly unidentified carriers, and the occasional patient with an active infection. Among the most common sites for positive MRSA colonization are the nares and mouth (saliva). Ohio State University (OSU) dental students perform routine restorative dental care onsite in local nursing homes using portable equipment including handpieces that can generate aerosols. Using a series of cultured test swabs and plates, this pilot study suggests that protection for both dental health care personnel and patients are provided by the following: 1. universal barrier precautions (for example, gloves, gowns, masks, hats, facial shields, glasses), 2. surface disinfectants, 3. pre-op 0.12% chlorhexidene mouth rinses, 4. high volume evacuation, 5. perioral skin scrubs. Additional infection control methods, techniques and equipment were evaluated and compared including rubber dam isolation, hand excavation and bond technique, high-speed air turbine and electric "high" speed handpiece. There was no indication of a special tendency or heightened ability of MRSA to aerosolize.

Trends in antibiotic use and cost and influence of case-mix and infection rate on antibiotic-prescribing in a long-term care facility

BACKGROUND

Antibiotic use and cost indicators have been developed specifically for the long-term care facility (LTCF) setting. Approximately 50% of the variation in these indicators was explained by the variation in infection rate. The objectives of this study were to further assess the utility of the antibiotic use and cost indicators in a different LTCF and to determine the correlation of case-mix and these indicators.

METHODS

Antibiotic use and cost indicators were collected monthly by unit (N = 10) and by physician (N = 6) at a 433-bed LTCF in Syracuse, New York, from February 1999 to September 2001. Indicators included incidence (number of antibiotic courses per 1000 resident care-days) of antibiotic use, antibiotic utilization ratio ([AUR]; ratio of the number of antibiotic-days to the number of resident care-days), cost per antibiotic-day, and cost per resident care-day. Case-mix variation was measured with the case-mix index (CMI) of the Resource Utilization Group II system. Simple linear and multilinear regression analyses were used to evaluate correlations of continuous variables.

RESULTS

Among the 10 units or 6 physicians, there was a significant difference in the average values for all indicators. Correlation between unit- or physician-specific CMI and antibiotic use or cost indicators or infection rate was poor. However, there was a significant positive correlation between unit- or physician-specific infection rate and incidence of antibiotic use, AUR, and cost per resident care-day but not cost per antibiotic-day. With use of multilinear regression analysis to control for CMI and cost per antibiotic-day, infection rate was a significant predictor of incidence of antibiotic use (R2 = 0.65; P <.001) and AUR (R2 = 0.78; P <.001).

CONCLUSIONS

This study provides further evidence that the antibiotic use and cost indicators developed specifically for LTCFs can detect significant variation among units within a facility and among physicians. However, there was no correlation between CMI and antibiotic use or cost indicators. After controlling for case-mix variation and cost per antibiotic-day, variation in infection rate explained most of the variation in incidence of antibiotic use and AUR.

Cost effect of managing methicillin-resistant Staphylococcus aureus in a long-term care facility

OBJECTIVES

The purpose of this study was to measure the total consumption of resources involved in the care of a long-term care facility (LTCF) resident infected with methicillin-resistant Staphylococcus aureus (MRSA).

DESIGN

A retrospective cohort study.

SETTING

A 375-bed LTCF that provides two levels of care.

PARTICIPANTS

Ninety LTCF residents infected with Staphylococcus aureus (mean age +/- standard deviation for methicillin-sensitive Staphylococcus aureus (MSSA) patients = 85 +/- 8.8, for MRSA patients = 82 +/- 9.5, P =.127; 49 MSSA and 41 MRSA patients). Inclusion criteria consisted of identification of a positive S. aureus culture in addition to symptoms/signs consistent with infection. Patients colonized with S. aureus were excluded.

MEASUREMENTS

A standardized data collection tool was used to conduct chart and database review throughout the defined infection period. The type of information collected included demographic, infection characterization, antibiotic regimen, resource assessment, and cost data. The cost data were further categorized into total pharmaceutical, infection management, physician care, nursing care, and total infection cost.

RESULTS

One hundred eleven cases were identified, with 90 cases eligible for evaluation. No difference in population demographics was noted between groups. A significantly higher number of patients in the MRSA group had an indwelling device (P <.001), pressure ulcer(s) (P =.028), or diabetes mellitus (P =.007). There was a significantly higher number of patients with congestive heart failure in the MSSA group (P =.047), but no difference existed in the primary infection site (P =.297) or the incidence of patients with more than two comorbidities (P =.509). The infection characterization variables included were also similar between groups. The most prevalent infection site was the urinary tract (48%) followed by skin/skin structure (38%). Because the majority of patients (82%) developed infection at least 30 days after their LTCF admission, the infections may be considered to have been largely LTCF acquired. The median infection management cost of an MRSA infection was six times greater than that of a MSSA infection (P <.001), whereas the median associated nursing care cost was two times greater (P =.001). The median overall infection cost associated with MRSA was 1.95 times greater than that of MSSA (median (range): MSSA 1,332 US dollars (268-7,265 US dollars) vs MRSA 2,607 US dollars (849-8,895 US dollars), P <.001). Nursing care cost constituted the major portion of the overall infection cost in both groups (MSSA 51%, MRSA 48%). Evaluation of antimicrobial management revealed that infected residents were treated with a wide array of combination therapies (65% of patients received combination therapy).

CONCLUSIONS

The management of a resident infected with MRSA was much more costly to the LTCF than that of an MSSA-infected patient. The general care of the patient and not the specific antibiotic regimen influenced the large difference in cost between groups. The approach to the antibiotic management of these patients was variable. A more streamlined approach to infection management that facilitates a faster cure rate may dramatically lower resource consumption and improve patient outcomes.

Epidemiology of bloodstream infection in nursing home residents: evaluation in a large cohort from multiple homes

This study sought to reevaluate the epidemiology of bloodstream infection in nursing home residents. The records of 166 nursing home residents admitted to an urban, public, university-affiliated hospital with 169 episodes of bloodstream infection between January 1997 and April 2000 were retrospectively reviewed. The most common organisms isolated were Escherichia coli (27% of isolates), Staphylococcus aureus (18%; 29% were methicillin-resistant strains), and Proteus mirabilis (13%). There was minimal resistance to quinolones and third-generation cephalosporins among aerobic gram-negative bacilli. The most common sources were the urinary tract (51% of episodes) and the lungs (11%); a source was not identified in 22% of episodes. Hospital mortality was 18%. Independent predictors of hospital mortality were a pulmonary source of infection, systolic blood pressure <90 mm Hg, and leukocytosis >20,000 cells/mm3. Compared with other studies published in the past 2 decades, mortality was lower. The most common resistant organism was methicillin-resistant S. aureus.