Nosocomial infections in elderly patients in the United States, 1986-1990. National Nosocomial Infections Surveillance System

Epidemiological relatedness of methicillin-resistant Staphylococcus aureus from a tertiary hospital and a geriatric institution in Spain

From January 2000 to June 2002, 24 Staphylococcus aureus isolates were recovered from decubitus ulcers of patients in a geriatric institution, of which 17 (70.8%) were methicillin-resistant S. aureus (MRSA). Antibiotic resistance and DNA macrorestriction (pulsed-field gel electrophoresis; PFGE) patterns of the MRSA isolates were compared with a collection of 161 MRSA isolates from patients admitted to the institution's reference hospital. PFGE revealed the presence of five clonal types (found also in hospitalised patients) among the 17 MRSA isolates. The findings suggest nosocomial acquisition of the MRSA strains by five patients, with subsequent dissemination of the strains within the institution. The high rate of MRSA highlights the need for epidemiological analysis to control the dissemination of MRSA in long-term care facilities.

Risk factors for nosocomial pneumonia in a geriatric hospital: a control-case one-center study

OBJECTIVES

To determine the risk factors (RFs) and the incidence of nosocomial pneumonia (NP).

DESIGN

Control/case study conducted from January 1 to April 15, 1999. Prospective enrollment.

SETTING

Geriatric university hospital with long-, intermediate-, and short-term care facilities.

PARTICIPANTS

Inpatients aged 65 and older with NP.

MEASUREMENTS

NP diagnosis relied on at least two clinical signs of respiratory infection and on chest radiography. Each NP case was randomly paired with two controls and followed up for 30 days to determine complication and mortality rates. RFs between cases and controls were compared (chi-square test, odds ratio (OR), 95% confidence interval, significance level P =.05). RFs that were significant in univariate analysis were tested using multivariate analysis and logistic regression.

RESULTS

Seventy-five cases of NP were diagnosed in 2,142 patients. The average incidence rate was 3.5% (short-term facilities = 0.5%; intermediate-term facilities = 8.3%; long-term care facilities = 5.3%). The complication rate was 58.1%. The most frequent complications were recurrent NP, heart and respiratory failure, phlebitis, and pressure ulcers. The NP mortality rate was 12.2%. The independent RFs of NP were a history of NP during the previous 6 months (OR = 4.50) and oxygen therapy (OR = 16.15), P <.001. Additional RFs were severe malnutrition, heart failure, prescription of antibiotics during the month preceding the emerging NP, eating dependency, and feeding by nasogastric tube.

CONCLUSION

The main RF for NP is a history of pneumonia. NP prevention in geriatrics should rely on early management of respiratory infections and malnutrition, surveillance of oxygen therapy and enteral feeding, rational use of antibiotics, and adaptation to the patient's dependency.

Urinary tract infection trends in Latin American hospitals: report from the SENTRY antimicrobial surveillance program (1997-2000)

Urinary tract infections (UTI) are one of the most common infectious diseases diagnosed in outpatients as well as in hospitalized patients. The objective of this study was to report the frequency of occurrence and antimicrobial susceptibility of uropathogens collected in Latin America between 1997 to 2000 through the SENTRY Antimicrobial Surveillance Program. Antimicrobial susceptibility testing was performed and results interpreted using reference broth microdilution methods. In the 4 year period, a total of 1961 urine isolates from hospitalized patients were included. The patients' mean age was 51.3 years and most of the infections occurred among women (65.6%). Esherichia coli was the most frequent pathogen isolated followed by Klebsiella spp., Pseudomonas aeruginosa, and Proteus mirabilis. Among the E. coli isolates, piperacillin/tazobactam, aztreonam, extended-spectrum cephalosporins, carbapenems and amikacin constitute reasonable therapeutic options for treatment of serious UTI in Latin America (91.0-100.0% susceptible). High resistance rates to fluoroquinolones (17.5-18.9%) and trimethoprim/sulfamethoxazole (>45.0%) were observed among the E. coli. In contrast, nitrofurantoin displayed susceptibility rate of > 87.0%. Against Klebsiella spp. infections, the only effective therapeutic option would be the carbapenems due to the high number of isolates (>30.0%) producing extended-spectrum beta-lactamases (ESBL). Even the new fluoroquinolones showed limited activity against Klebsiella spp. (72.1-88.6% susceptible) and the P. aeruginosa isolates showed high resistance rates to most antimicrobial agents tested. The results of this survey endorse the importance of Enterobacteriaceae as cause of UTI in Latin America. Our results also demonstrate that the uropathogens isolated in the Latin American medical centers exhibit high resistance to various classes of antimicrobial agents. Carbapenem-resistant P. aeruginosa, ciprofloxacin-resistant E. coli, ESBL-producing K. pneumoniae constitute serious problem in this geographic region.

Ageing and infection

Average life expectancy throughout developed countries has rapidly increased during the latter half of the 20th century and geriatric infectious diseases have become an increasingly important issue. Infections in the elderly are not only more frequent and more severe, but they also have distinct features with respect to clinical presentation, laboratory results, microbial epidemiology, treatment, and infection control. Reasons for increased susceptibility include epidemiological elements, immunosenescence, and malnutrition, as well as a large number of age-associated physiological and anatomical alterations. Moreover, ageing may be the cause of infection but infection can also be the cause of ageing. Mechanisms may include enhanced inflammation, pathogen-dependent tissue destruction, or accelerated cellular ageing through increased turnover. In most instances, treatment of infection leads to a satisfactory outcome in the elderly. However, in palliative care situations and in patients with terminal dementia, the decision whether or not to treat an infectious disease is becoming a difficult ethical issue.

Bloodstream infection: differences between young-old, old, and old-old patients

OBJECTIVES

To compare the epidemiological and microbiological characteristics of bloodstream infection (BSI) between the young old (65-75), old (76-85), and old old (>85).

DESIGN

Retrospective study.

SETTING

Forty-six hospitals in southeast France.

PARTICIPANTS

One thousand seven hundred forty patients aged 65 and older with BSI, seen between January 1 and December 31, 1998.

MEASUREMENTS

Epidemiological and microbiological data and outcome.

RESULTS

Community-acquired BSIs (CABSIs) were significantly more frequent in the old old, but microbiological data were similar to those in the young-old group. Conversely, microbiological data were significantly different for nosocomial BSIs (NSBIs). Escherichia coli was the main pathogen in the old old and Staphylococcus aureus in the young old. Mortality was independently associated with the presence of methicillin-resistant S. aureus in NSBI and CABSI.

CONCLUSIONS

The differences in NBSI are important in serious infectious diseases and often require empirical antibiotic therapy. Age is also a risk factor but only for CABSI and suggests that the old-old patients represent a frail population in the community. Further prospective studies are needed to confirm these findings and analyze predisposing factors.

Incidence and risk factors for acquiring nosocomial urinary tract infection in the critically ill

PURPOSE

A urinary tract infection (UTI) is the most common hospital-acquired infection. However, the epidemiology of intensive care unit (ICU)-acquired UTIs is not well defined. The objective of this study was to describe the incidence, risk factors, and clinical outcomes of ICU-acquired UTIs.

MATERIALS AND METHODS

All patients admitted to adult multidisciplinary ICUs in the Calgary Health Region (CHR, population approximately 1 million) during May 1, 1999 to April 30, 2000 were studied using a cohort design.

RESULTS

A total of 1,158 admissions to a CHR ICU were 48 hours in duration or more. A total of 111 episodes of ICU-acquired UTI (defined as >10(5) CFU/mL of 1 or 2 organisms >48 hours after ICU admission) occurred in 105 (9%) patients and 5 (0.4%) had ICU-acquired bacteremic/fungemic UTIs for incidences of 11.3 and 0.5 UTIs per 1,000 ICU days, respectively. Significant independent risk factors for developing an ICU-acquired UTI as determined by a logistic regression model were female gender (adjusted odds ratio [OR(adj)], 2.31; 95% confidence interval [CI], 1.48-3.59) and natural logarithmic transformation of ICU length of stay (OR(adj), 3.96; 95% CI, 3.02-5.17). No differences in admitting vital signs, routine blood tests, APACHE II and TISS scores, or overall hospital mortality rate were observed among patients who developed an ICU-acquired UTI as compared with those who did not. The most common UTI etiologies were Enterococcus spp. (24%), Candida albicans (21%), and Escherichia coli (15%). Only 4 (3%) of the organisms were highly antibiotic resistant.

CONCLUSIONS

Nosocomial UTIs develop commonly in the critically ill and women and those with an extended ICU stay are at increased risk. Although ICU-acquired UTIs are markers of morbidity, they do not significantly increase mortality.

Staphylococcus aureus infections and antibiotic resistance in older adults

The prevalence of infection with Staphylococcus aureus among older adults is unknown, but clinical syndromes caused by this organism are common. Bacteremia, pneumonia, endocarditis, and bone and joint infections are encountered with relative frequency in this population, and the clinical presentation may be atypical. Underlying disease and functional debility, rather than age itself, predispose the older adult to staphylococcal carriage and infection. Infections with methicillin-resistant strains of S. aureus are acquired primarily in hospital, rather than in nursing homes or in the community. Lack of clinical suspicion for S. aureus infection and delays in appropriate therapy can be fatal. Staphylococcal infection should be considered for an older adult with risk factors for staphylococcal carriage, comorbid illness, debility, and history of recent hospitalization or nursing home stay. Choices regarding empirical therapy should be made on the basis of knowledge of local antibiotic susceptibility patterns.

Antibiotic duration for treating uncomplicated, symptomatic lower urinary tract infections in elderly women

BACKGROUND

Urinary tract infections are common in elderly patients. Authors of non systematic literature reviews often recommend longer treatment durations (7-14 days) for older patients than for younger women, but the scientific evidence for such recommendations is not clear.

OBJECTIVES

To determine the optimal duration of antibiotic treatment for uncomplicated symptomatic lower urinary tract infections in elderly women.

SEARCH STRATEGY

We contacted known investigators and pharmaceutical companies marketing antibiotics used to treat urinary tract infections, screened the reference list of identified articles, reviews and books, and searched the following data bases: MEDLINE, EMBASE, CINAHL, Healthstar, Popline, Gerolit, Bioethics Line, The Cochrane Library, Dissertation Abstracts International, Index to Scientific & Technical Proceedings.

SELECTION CRITERIA

All randomized controlled trials in which different treatment durations of oral antibiotics for uncomplicated symptomatic lower urinary tract infections in elderly women were compared. We excluded patients with fever or flank pain and those with complicating factors. Trials with treatment durations longer than 14 days or designed for prevention of urinary tract infection were also excluded. No language restriction was applied.

DATA COLLECTION AND ANALYSIS

The quality of all selected trials was assessed and data extracted by the reviewers. Main outcome measures were persistence of urinary symptoms (short-term and long-term efficacy), effect on mental and functional status and adverse drug reactions. To compare the different treatment durations, we defined the following categories of duration: single dose, short course (3-6 days) and long course (7-14 days). Relative risk (RR) and 95% confidence intervals (CI) were calculated for each trial and outcome and were then combined using a random effects model.

MAIN RESULTS

Thirteen trials were included in this review. Six trials compared single dose with short-term treatment (3-6 days), three studies single dose with long-term treatment (7-14 days) and four trials short-term with long term treatment. Eight trials also included younger patients, but provided a subgroup analysis for elderly women. The methodological quality of all trials was low. All trials reported results of bacteriological cure rate; less often clinical outcomes (e.g. improvement or cure of symptoms) were analyzed. Only five trials compared the same antibiotic given for a different length of time. We performed a separate analysis for these trials. The rate of persistent bacteriuria rate at short-term (two weeks post-treatment) was better in the longer treatment group (3-14 days) than in the single dose group (RR 1.84, 95% CI 1.18 to 2.86). However, the rate of persistent bacteria at long term and the clinical cure rate showed no statistically significant difference between the two groups. Patients showed a preference for single dose treatment (RR 0.73, 95% CI 0.66 to 0.88), however this was based on only one trial comparing the same antibiotic. The comparison of short (3-6 days) and longer treatments (7-14 days) did not show any significant difference, but the number of included studies and sample size were low.

REVIEWER'S CONCLUSIONS

This review suggests that single dose antibiotic treatment is less effective but may be better accepted by the patients than longer treatment durations (3-14 days). In addition there was no significant difference between short course (3-6 days) versus longer course (7-14 days) antibiotics. The methodological quality of the identified trials was poor and the optimal treatment duration could not be determined. We therefore need more appropriately designed randomized controlled trials testing the effect, - on clinical relevant outcomes -, of different treatment durations of a given antibiotic in a strictly defined population of elderly women.

Nosocomial infections in geriatric long-term-care and rehabilitation facilities: exploration in the development of a risk index for epidemiological surveillance

OBJECTIVE

To compute a risk index for nosocomial infection (NI) surveillance in geriatric long-term-care facilities (LTCFs) and rehabilitation facilities.

DESIGN

Analysis of data collected during the French national prevalence survey on NIs conducted in 1996. Risk indices were constructed based on the patient case-mix defined according to risk factors for NIs identified in the elderly.

SETTING

248 geriatric units in 77 hospitals located in northern France.

PARTICIPANTS

All hospital inpatients on the day of the survey were included.

RESULTS

Data from 11,254 patients were recorded. The overall rate of infected patients was 9.9%. Urinary tract, respiratory tract, and skin were the most common infection sites in both rehabilitation facilities and LTCFs. Eleven risk indices, categorizing patients in 3 to 7 levels of increasing NI risk, ranging from 2.7% to 36.2%, were obtained. Indices offered risk adjustment according to NI rate stratification and clinical relevance of risk factors such as indwelling devices, open bedsores, swallowing disorders, sphincter incontinence, lack of mobility, immunodeficiency, or rehabilitation activity.

CONCLUSION

The optimal index should be tailored to the strategy selected for NI surveillance in geriatric facilities in view of available financial and human resources.

Pneumonia in the elderly

Pneumonia, including community-acquired, LTCF-acquired, and nosocomial infections, is a major cause of morbidity and mortality among the elderly. The aged with pneumonia often present with atypical features, including confusion, lethargy, and general deterioration of condition (silent infection). Further investigations, such as a chest radiograph frequently are required for diagnosis. The chest radiograph may be normal early on in the course of infection, particularly in dehydrated patients. The elderly are hospitalized more frequently for pneumonia, have a greater need for intravenous therapy, have a longer hospital stay, have a more prolonged course, have greater morbidity, and ultimately have a poorer outcome. Nevertheless, it may not be chronologic age per se that has a negative impact on the manifestations and outcome of pneumonia in the elderly, but rather the presence of underlying comorbid illness. The mainstay of therapy for pneumonia is antibiotics, and studies in the community and hospital have confirmed the important positive impact of early appropriate empiric therapy on outcome. Many relatively simple procedures, including attention to nutrition, influenza and pneumococcal vaccination, and avoidance of intubation, may help limit the occurrence of such infections.

[Annual incidence and risk factors for nosocomial bacterial infections in an acute care geriatric unit]

PURPOSE

Elderly inpatients are particularly exposed to the risk of nosocomial infections, thus the study of their risk factors and consequences is of interest.

METHODS

Among 1,565 subjects referred to a short-term geriatric unit, patients hospitalised for a year for an acute event and unable to move themselves were followed up for the occurrence of nosocomial infections.

RESULTS

Among these 402 immobilised patients (age: 86.3 +/- 7.6 years), 102 nosocomial infections occurred in 91 patients (22.6%), whereas the estimation of the incidence in the total hospitalised population (1,565 subjects, age: 85.1 +/- 6.2 years) was 9.4% (95% confidence interval [CI] 8.3-11.2). Forty-seven point seven percent of nosocomial infections were urinary tract nosocomial infections, 27.5% were lower respiratory nosocomial infections, 9.2% were cutaneous nosocomial infections, 7.3% were septicaemia and 8.2% were of unknown origin. The relative risk (RR) of NI linked to functional dependency for mobility was 5.5 (95% CI: 3.93-7.7, P < 0.001). Other risk factors were: for all nosocomial infections: cancer diagnosis (RR 1.1, 95% CI: 1.1-1.2, P = 0.01); and respectively for urinary tract NI: bladder indwelling (RR 4.8, 95% CI: 2.9-7.7, P < 0.001), pulmonary NI: swallowing disorders (RR 5.4, 95% CI: 2.8-10.5, P < 0.001); and septicaemia: venous catheter (RR 5.4, 95% CI: 1.3-23.3, P = 0.002). NI were associated with an increased length of stay (22.1 +/- 11.7 days in infected patients vs 16.3 +/- 9.5 days in immobilised non-infected subjects, P < 0.001). The mean length of stay for the 1,565 subjects was 10.3 +/- 7.6 days. Death was attributed to nosocomial infections in 13 subjects. In conclusion, functional dependency for mobility, bladder indwelling, venous catheter, swallowing disorders and diagnosis of cancer were risk factors for nosocomial infections in hospitalised elderly subjects in an acutecare setting.

Emerging health care-associated infections in the geriatric population

The increasing number of persons >65 years of age form a special population at risk for nosocomial and other health care-associated infections. The vulnerability of this age group is related to impaired host defenses such as diminished cell-mediated immunity. Lifestyle considerations, e.g., travel and living arrangements, and residence in nursing homes, can further complicate the clinical picture. The magnitude and diversity of health care-associated infections in the aging population are generating new arenas for prevention and control efforts.

Are physicians aware of which of their patients have indwelling urinary catheters?

PURPOSE

Although infections associated with indwelling urinary catheters are common, costly, and morbid, the use of these catheters is unnecessary in more than one-third of patients. We sought to assess whether attending physicians, medical residents, and medical students are aware if their hospitalized patients have an indwelling urinary catheter, and whether physician awareness is associated with appropriate use of these catheters.

METHODS

The physicians and medical students responsible for patients admitted to the medical services at four university-affiliated hospitals were given a list of the patients on their service. For each patient, the provider was asked: "As of yesterday afternoon, did this patient have an indwelling urethral catheter?" Respondents' answers were compared with the results of examining the patient.

RESULTS

Among 288 physicians and students on 56 medical teams, 256 (89%) completed the survey. Of 469 patients, 117 (25%) had an indwelling catheter. There were a total of 319 provider-patient observations among these 117 patients. Overall, providers were unaware of catheterization for 88 (28%) of the 319 provider-patient observations. Unawareness rates by level of training were 21% for students, 22% for interns, 27% for residents, and 38% for attending physicians (P = 0.06). Catheter use was inappropriate in 36 (31%) of the 117 patients with a catheter. Providers were unaware of catheter use for 44 (41%) of the 108 provider-patient observations of patients who were inappropriately catheterized. Catheterization was more likely to be appropriate if respondents were aware of the catheter (odds ratio = 3.7; 95% confidence interval, 2.1 to 6.7, P <0.001).

CONCLUSION

Physicians are commonly unaware that their patients have an indwelling urinary catheter. Inappropriate catheters are more often "forgotten" than appropriate ones. System-wide interventions aimed at discontinuing unnecessary catheterization seem warranted.

Impact of hospital-wide surveillance on hospital-acquired infections in an acute-care hospital in the Netherlands

The goal of surveillance is to identify hospital-acquired infections (HAI) and risk factors, to apply targeted interventions and to evaluate their effect in an ongoing system. Continuing active surveillance in a 270-bed acute-care hospital is being performed on clinical patients, excluding day-care. The period 1984-1997 is described here. Specific surveillance-based interventions included the introduction of antimicrobial prophylaxis in gynaecology patients with postoperative urinary tract catheters and inpatients scheduled for appendicectomy and hysterectomy. General measures included education, implementation of protocols, feedback of surgeon-specific infection rates. In total, 3545 HAI were found in 13 years of surveillance. The incidence was 4.7/100 admissions and 4. 5/1000 patient days. Age-specific incidences ranged from 1.3 in the age-category 1-14 years, to 10.2 in patients aged 75 years and above. If age-specific incidences had remained at their 1984 level, over 3000 additional infections would have occurred, affecting all age groups except those up to 14 years. The distribution of types of infections differed between services. Following the targeted interventions, the rate of infections in gynaecology decreased from 19.4 per 1000 patient days in 1984 to 2.4 per 1000 patient days in 1996. The rates of wound infection following appendicectomy and hysterectomy decreased by 69% and 82%, respectively, in the period following the institution of antimicrobial prophylaxis. Over 4000 micro-organisms were isolated from the HAI; multi-resistant strains were isolated sporadically. We conclude that hospital-wide surveillance of hospital-acquired infections provides appropriate targets for interventions tailored to the specific needs of the hospital. The impact of such interventions can readily be documented from the surveillance data.

Clinical and economic consequences of nosocomial catheter-related bacteriuria

Indwelling catheters are strongly associated with the development of bacteriuria, which can lead to significant morbidity in hospitalized patients. This report, a review of the literature, evaluates the infectious outcomes of patients with indwelling catheters to determine the precise clinical and economic impact of catheter-related infection. Statistical pooling was used to estimate the incidence of bacteriuria in hospitalized patients with indwelling catheters. In addition, the proportion of patients with catheter-related bacteriuria in whom symptomatic urinary tract infection and bacteremia will develop was estimated through quantitative synthesis of previous reports. Costs were estimated by using microcosting techniques. Of patients who have indwelling catheters for 2 to 10 days, bacteriuria is expected to develop in 26% (95% confidence interval [CI], 23% to 29%). Among patients with bacteriuria symptoms of urinary tract infection will develop in 24%, (95% CI, 16% to 32%), and bacteremia from a urinary tract source will develop in 3.6% (95% CI, 3.4% to 3.8%). Each episode of symptomatic urinary tract infection is expected to cost an additional $676, and catheter-related bacteremia is likely to cost at least $2836. Given the clinical and economic burden of urinary catheter-related infection, infection control professionals and hospital epidemiologists should use the latest infection control principles and technology to reduce this common complication.

Pneumonia in the elderly

Pneumonia, including community-acquired, long-term care facility-associated, and nosocomial infections, is a major cause of morbidity and mortality in the elderly. The aged with pneumonia often present with atypical features, including confusion, lethargy, and general deterioration of condition (so-called "silent infection"). Further investigations, such as a chest radiograph, are more frequently required for diagnosis, but even these results may be normal early in the course of infection, particularly in dehydrated patients. The elderly are more frequently hospitalized for pneumonia and have a greater need for intravenous therapy, longer hospital stay, more prolonged course, greater morbidity, and, ultimately, a poorer outcome. Yet in many studies it is not chronological age per se that impacts negatively on the manifestations of pneumonia in the elderly but rather the presence of comorbid illness. Antibiotic therapy remains the mainstay of therapy for pneumonia, and both community and hospital-based studies confirm the important positive impact of early appropriate empiric antibiotic therapy on outcome. Attention to nutrition and hydration, the use of pneumococcal and influenza vaccination, and a number of diverse procedures in the hospital setting may help limit the occurrence and impact of such infections.

Methicillin-resistant Staphylococcus aureus: long-term care concerns

Colonization of residents of long-term care facilities with methicillin-resistant Staphylococcus aureus (MRSA) is an important healthcare concern. MRSA colonization is prevalent; in two of the most common sites of colonization, nares and wounds, colonization rates range from 8% to 53%, and 30% to 82%, respectively. With such a large number of patients harboring the organism, it is imperative that long-term care facilities are knowledgeable regarding the overall significance of MRSA, are aware of MRSA infection rates at their facilities, and have established a threshold above which outbreak precautions will be instituted. More importantly, facilities must ensure that appropriate precautions (e.g., hand washing, glove changes, gowns) are utilized to prevent transmission of MRSA to noncolonized residents. If these basic measures are taken, MRSA-colonized residents of long-term facilities should be able to be fully integrated into the everyday activities within the long-term care environment. In the event of an outbreak of MRSA infection, stricter isolation of colonized and infected residents is warranted, and such isolation should be discontinued as soon as the chain of transmission has been disrupted. Systemic antibiotics should be avoided in asymptomatic colonized patients; topical antibiotics like mupirocin should be reserved for short-term administration in outbreak situations.

Implications of oral infections on systemic diseases in the institutionalized elderly with a special focus on pneumonia

Systemic infection in the elderly patient living in a chronic care setting presents a significant burden to the health care system. The extent to which oral organisms cause systemic infections through hematogenous dissemination in the institutionalized elderly is still unknown. A more likely and common route of systemic infection by oral microorganisms is through aspiration of oropharyngeal fluids containing oral pathogenic microorganisms, which colonize the lower respiratory tract and cause pneumonia. Respiratory pathogens emerge in the dental plaque of elderly patients with very poor oral hygiene and severe periodontal disease. In the chronic care setting, aspiration of oropharyngeal fluids contaminated with these bacteria occurs in patients with diminished host defenses, resulting in bacterial pneumonia. This is also a problem in intensive care units in the hospital setting. In one study, pre-rinsing with a 0.12% chlorhexidine gluconate mouthwash significantly lowered the mortality rate from postsurgical pneumonia in patients undergoing open heart surgery. Selective digestive decontamination, a technique involving the topical application of antimicrobials to reduce the risk of colonization of the respiratory tract, has been used to reduce the incidence of nosocomial pneumonia in the acute care setting of hospitals. This technique has not been employed in the nursing home setting. Whether improving oral hygiene would also lower the risk in either of these settings has not been studied. A number of obstacles must be overcome in designing studies to investigate the relationship between oral infections and lung infections in the institutionalized elderly. Ethical issues must be addressed, and full collaboration of the medical team is required. Future studies should establish whether reducing the risk for pneumonia in the institutionalized elderly is possible through improved oral health.

Catheter-associated urinary tract infections

Millions of urethral catheters are used each year. This device subverts several host defenses to allow bacterial entry at the rate of 3% to 10% incidence per day, and its presence encourages the organism's persistent residence in the urinary tract. Most catheter-associated bacteriurias are asymptomatic. The complications in short-term catheterized patients include fever, acute pyelonephritis, bacteremia, and death; patients with long-term catheters in place are at risk for these complications and catheter obstruction, urinary tract stones, local periurinary infections, chronic renal inflammation, chronic pyelonephritis, and, over years, bladder cancer. The closed catheter system has been a magnificant step forward in the prevention of catheter-associated bacteriuria. Indeed, only two catheter principles are universally recommended: keep the closed catheter system closed and remove the catheter as soon as possible. Most modifications of the closed catheter system have not improved markedly on its ability to postpone bacteriuria. On first inspection, systemic antibiotics seem to be an exception to this rule, but their use results in infection of the bladder with resistant organisms, including candida. This and the effect of side effects on the patient and emergence of resistant bacteria in the medical unit have led most authorities to conclude that antibiotics are not useful for prevention of bacteriuria, nor for treatment of bacteriuria in the asymptomatic catheterized patient. For symptomatic patients, usually with fever or signs of sepsis, treatment of bacteriuria with appropriate systemic antibiotics and removal or replacement of the urethral catheter are indicated. Gloves, hand washing, and segregation of catheterized patients can minimize nosocomial clusters. Because clinicians can only postpone bacteriuria, and once it occurs, clinicians seem unable to prevent its complications, methodologies other than urethral catheters should be used for urine drainage assistance whenever possible. These options include condom, intermittent, suprapubic, and intraurethral catheterization for appropriate patients. The few data available suggest that each one of these catheterization options yields a lower incidence of bacteriuria-and its consequent complications-than urethral catheterization.

Catheter patrols: a unique way to reduce the use of convenience urinary catheters

The increased risk of infections among elders has been was documented. Elder patients often have atypical signs and symptoms that lead to delays in diagnosis and treatment of infection. Urinary incontinence is often overlooked as a sign of infection because of the stereotypical belief that urinary incontinence is a normal part of the aging process. This belief can lead to overuse of indwelling urinary catheters and place the elder patient at even greater risk for infection. The Centers for Disease Control and Prevention's "Guidelines for Prevention of Catheter-Associated Urinary Tract Infections" lists four criteria that are helpful in determining appropriate urinary catheter usage. These guidelines, along with ongoing nursing assessment of the patient's urinary catheter need, play an important role in protecting elder patients from unnecessary catheter-associated urinary tract infections.

Factors associated with a significant reduction in hospital-wide infection rates

OBJECTIVE

The purpose of this study was to identify factors associated with a significant reduction in hospital-wide nosocomial infection rates.

METHODS

Methods included a 3-year retrospective and a 10-month prospective follow-up study in a 500-bed hospital with total surveillance, with data collected by two ICPs using Centers for Disease Control and Prevention (CDC) definitions.

RESULTS

Infection rates averaged 3.9% over a decade and dropped in 1993 to 2.6% (p < 0.001). This change was unexplained by changes in surveillance methods. Slightly shorter lengths of stay and fewer inpatient surgeries may have had some impact. Additionally, two factors were temporally and statistically associated with the reduction: hospital-wide introduction of the Occupational Health and Safety Administration (OSHA) Blood-borne Pathogen Exposure Control Plan and Body Substance Isolation, and a barrier hand foam.

CONCLUSIONS

Introduction of the OSHA Control Plan, with concomitant increase in glove use and widespread use of a barrier hand foam were associated with a significant reduction in nosocomial infection rates. Other demographic variables (shorter hospital stays and less inpatient surgery) probably also played a role. Risk-adjusted rates are necessary to make within-hospital comparisons over time.

Hospital-acquired infections: diseases with increasingly limited therapies

About 5% of patients admitted to acute-care hospitals acquire nosocomial infections. A variety of factors contribute: increasing age of patients; availability, for treatment of formerly untreatable diseases, of extensive surgical and intensive medical therapies; and frequent use of antimicrobial drugs capable of selecting a resistant microbial flora. Nosocomial infections due to resistant organisms have been a problem ever since infections due to penicillinase-producing Staphylococcus aureus were noted within a few years of the introduction of penicillin. By the 1960s aerobic Gram-negative bacilli had assumed increasing importance as nosocomial pathogens, and many strains were resistant to available antimicrobials. During the 1980s the principal organisms causing nosocomial bloodstream infections were coagulase-negative staphylococci, aerobic Gram-negative bacilli, S. aureus, Candida spp., and Enterococcus spp. Coagulase-negative staphylococci and S. aureus are often methicillin-resistant, requiring parenteral use of vancomycin. Prevalence of vancomycin resistance among enterococcal isolates from patients in intensive care units has increased, likely due to increased use of this drug. Plasmid-mediated gentamicin resistance in up to 50% of enterococcal isolates, along with enhanced penicillin resistance in some strains, leaves few therapeutic options. The emergence of Enterobacteriaceae with chromosomal or plasmid-encoded extended spectrum beta-lactamases presents a world-wide problem of resistance to third generation cephalosporins. Control of these infections rests on (i) monitoring infections with such resistant organisms in an ongoing fashion, (ii) prompt institution of barrier precautions when infected or colonized patients are identified, and (iii) appropriate use of antimicrobials through implementation of antibiotic control programs.

The National Nosocomial Infections Surveillance System: plans for the 1990s and beyond

The National Nosocomial Infections Surveillance (NNIS) System is an ongoing collaborative surveillance system among the Centers for Disease Control (CDC) and United States hospitals to obtain national data on nosocomial infections. This system provides comparative data for hospitals and can be used to identify changes in infection sites, risk factors, and pathogens, and develop efficient surveillance methods. Data are collected prospectively using four surveillance components: hospital-wide, intensive care unit, high-risk nursery, and surgical patient. The limitations of NNIS data include the variability in case-finding methods, infrequency or unavailability of culturing, and lack of consistent methods for post-discharge surveillance. Future plans include more routine feedback of data, studies on the validity of NNIS data, new components, a NNIS consultant group, and more rapid data exchange with NNIS hospitals. Increasing the number of NNIS hospitals and cooperating with other agencies to exchange data may allow NNIS data to be used better for generating benchmark nosocomial infection rates. The NNIS system will continue to evolve as it seeks to find more effective and efficient ways to measure the nosocomial infection experience and assess the influence of patient risk, changes in the delivery of hospital care, and changes in infection control practices on these measures.