Antimicrobial therapy for the elderly patient

Risk factors associated with increased discontinuation rate of trimethoprim-sulfamethoxazole used as a primary prophylaxis for Pneumocystis pneumonia: A retrospective cohort study

BACKGROUND

The use of trimethoprim-sulfamethoxazole (TMP-SMX) for Pneumocystis pneumonia (PcP) prophylaxis is often discontinued owing to adverse drug reactions. Half-dosage of TMP-SMX (40/200 mg daily) is considered more tolerable than the conventional dosage (80/400 mg daily). However, patient background characteristics that are associated with the discontinuation of TMP-SMX prophylaxis and suitable for reduced dosage remain unclear. In this study, we aimed to identify the risk factors for the discontinuation of and efficacy of different doses of TMP-SMX prophylaxis in patients with creatinine clearance higher than 30 mL/min.

METHODS

We retrospectively evaluated 318 immunocompromised non-human immunodeficiency virus (HIV)-infected patients (194 men and 124 women; median age, 68.5 [interquartile range, 59-75] years) who underwent TMP-SMX therapy as a primary PcP prophylaxis between July 2014 and August 2019. The patients were segregated into two groups on the basis of dosage: single-strength (SS; n = 244) and half-strength (HS; n = 74) groups. We evaluated PcP occurrence, TMP-SMX discontinuation rate, and discontinuation-related risk factors in these groups.

RESULTS

PcP did not occur in either group. The univariate and multivariate Cox proportional hazards models revealed that the SS dosage and renal function (e.g. serum creatinine and creatinine clearance) were independently associated with prophylaxis discontinuation. At 24 weeks, the HS group presented significantly lower discontinuation rates than the SS group (P = 0.019, log-rank test). In the SS group, patients with mild renal impairment (e.g. serum creatinine ≥0.78 mg/dL or creatinine clearance ≤64.26 mL/min) presented significantly higher TMP-SMX discontinuation rates than those without such an impairment (P < 0.05, log-rank test with Bonferroni correction). This difference was not significant in the HS group.

CONCLUSION

Mild renal impairment might increase the risk of discontinuation of conventional TMP-SMX prophylaxis. In patients with a mild renal impairment, the HS dosage may improve tolerability while maintaining prophylactic efficacy.

Comparison of gram-negative and gram-positive hematogenous pyogenic spondylodiscitis: clinical characteristics and outcomes of treatment

Background

To the best of our knowledge, no study has compared gram-negative bacillary hematogenous pyogenic spondylodiscitis (GNB-HPS) with gram-positive coccal hematogenous pyogenic spondylodiscitis (GPC-HPS) regarding their clinical characteristics and outcomes.

Methods

From January 2003 to January 2013, 54 patients who underwent combined antibiotic and surgical therapy in the treatment of hematogenous pyogenic spondylodiscitis were included.

Results

Compared with 37 GPC-HPS patients, the 17 GNB-HPS patients were more often found to be older individuals, a history of cancer, and a previous history of symptomatic urinary tract infection. They also had a less incidence of epidural abscess formation compared with GPC-HPS patients from findings on magnetic resonance imaging (MRI). Constitutional symptoms were the primary reasons for initial physician visits in GNB-HPS patients whereas pain in the affected spinal region was the most common manifestation in GPC-HPS patients at initial visit. The clinical outcomes of GNB-HPS patients under combined surgical and antibiotic treatment were not different from those of GPC-HPS patients. In multivariate analysis, independent predicting risk factors for GNB-HPS included a malignant history and constitutional symptoms and that for GPC-HPS was epidural abscess.

Conclusions

The clinical manifestations and MRI presentations of GNB-HPS were distinguishable from those of GPC-HPS.

New Developments in Antibacterial Choice for Lower Respiratory Tract Infections in Elderly Patients

Elderly patients are at increased risk of developing lower respiratory tract infections compared with younger patients. In this population, pneumonia is a serious illness with high rates of hospitalisation and mortality, especially in patients requiring admission to intensive care units (ICUs). A wide range of pathogens may be involved depending on different settings of acquisition and patient's health status. Streptococcus pneumoniae is the most common bacterial isolate in community-acquired pneumonia, followed by Haemophilus influenzae, Moraxella catarrhalis and atypical pathogens such as Chlamydia pneumoniae, Legionella pneumophila and Mycoplasma pneumoniae. However, elderly patients with comorbid illness, who have been recently hospitalised or are residing in a nursing home, may develop severe pneumonia caused by multidrug resistant staphylococci or pneumococci, and enteric Gram-negative bacilli, including Pseudomonas aeruginosa. Moreover, anaerobes may be involved in aspiration pneumonia. Timely and appropriate empiric treatment is required in order to enhance the likelihood of a good clinical outcome, prevent the spread of antibacterial resistance and reduce the economic impact of pneumonia. International guidelines recommend that elderly outpatients and inpatients (not in ICU) should be treated for the most common bacterial pathogens and the possibility of atypical pathogens. The algorithm for therapy is to use either a selected beta-lactam combined with a macrolide (azithromycin or clarithromycin), or to use monotherapy with a new anti-pneumococcal quinolone, such as levofloxacin, gatifloxacin or moxifloxacin. Oral (amoxicillin, amoxicillin/clavulanic acid, cefuroxime axetil) and intravenous (sulbactam/ampicillin, ceftriaxone, cefotaxime) beta-lactams are agents of choice in outpatients and inpatients, respectively. For patients with severe pneumonia or aspiration pneumonia, the specific algorithm is to use either a macrolide or a quinolone in combination with other agents; the nature and the number of which depends on the presence of risk factors for specific pathogens. Despite these recommendations, clinical resolution of pneumonia in the elderly is often delayed with respect to younger patients, suggesting that optimisation of antibacterial therapy is needed. Recently, some new classes of antibacterials, such as ketolides, oxazolidinones and streptogramins, have been developed for the treatment of multidrug resistant Gram-positive infections. However, the efficacy and safety of these agents in the elderly is yet to be clarified. Treatment guidelines should be modified on the basis of local bacteriology and resistance patterns, while dosage and/or administration route of each antibacterial should be optimised on the basis of new insights on pharmacokinetic/pharmacodynamic parameters and drug interactions. These strategies should be able to reduce the occurrence of risk factors for a poor clinical outcome, hospitalisation and death.

Pneumonia in the elderly

Pneumonia is one of the commonest infections in elderly patients. The pathogens responsible for pneumonias in the elderly are the same as in younger adults. Because of associated cardiopulmonary disease and/or impaired host defenses, pneumonia in elderly patients is associated with increased mortality and morbidity compared to younger patients. The clinical importance of pneumonias in the elderly relates to age-dependent and pathologic changes in the immune system as well as the lungs. Pneumonias in the elderly may be classified, for clinical purposes, according to their location of acquisition, i.e. community-acquired pneumonias, nursing home-acquired pneumonias, or hospital-acquired pneumonias. The clinical presentation of pneumonias in the elderly may be difficult, due to pre-existing cardiopulmonary disease that mimics pneumonia. This review discusses the diagnostic and therapeutic approaches to elderly patients with pneumonia.

Antimicrobial therapy in the elderly

This article focuses on the special characteristics of infection in the elderly and provides an update of the principles of antibiotic selection, use of specific antibiotics, and empiric use of antimicrobials in the treatment of infectious diseases in this particularly vulnerable group. Antituberculous, antifungal, and antiviral agents are mentioned briefly; detailed information regarding these classes of agents in reference to aging can be found in standard reviews of antimicrobial therapy in the elderly.

Drug-induced seizures in the elderly. Causative agents and optimal management

We conducted a review of drugs that were most commonly associated with inducing seizures in the elderly population. The method for determining the risk of these agents includes evaluating the utilisation and the percentage of adverse events in previous studies and case reports. Classes of medications, such as anti-psychotics and antidepressants, are extensively reviewed to provide the clinician with treatment options in high risk patients. The risk of seizures secondary to the withdrawal of alcohol (ethanol) and benzodiazepines, and methods employed to minimise the risk are discussed. In addition, the management of patients with drug-induced seizures is delineated. Drug-induced seizures are a potentially serious adverse effect. It is important that clinicians are aware of which classes of medications and individual medications are associated with reducing seizure threshold.

Treatment of infections in elderly patients

Infections are common in elderly persons. The clinical manifestations of infection may be atypical or absent in the elderly. The microbial cause for many common infections may be more diverse in elderly patients, and obtaining diagnostic clinical specimens often is more difficult. Aging is associated with changes in pharmacokinetics and a higher rate of adverse drug reactions. These factors impact on the approach to treating infections in the elderly.

Whether to transfer? Factors associated with hospitalization and outcome of elderly long-term care patients with pneumonia

OBJECTIVE

To determine factors associated with the decision to treat elderly long-term care patients with pneumonia in the hospital vs in the long-term care facility (LTCF) and factors associated with patient outcomes.

DESIGN

Retrospective cohort study.

SETTING

Hebrew Rehabilitation Center for Aged.

PATIENTS

Nursing home residents who had an episode of pneumonia, defined as a new respiratory sign or symptom and a new infiltrate.

MEASUREMENTS AND MAIN RESULTS

The majority of the 316 pneumonia episodes (78%) were managed in the LTCF, most (77%) with oral antibiotics. Both patient-related factors, such as elevated respiratory rate, and non-patient-related factors, such as evening evaluation, were associated with hospitalization. No patient who had a do-not-hospitalize (DNH) order was hospitalized. Equal proportions of patients given LTCF therapy (87%) and hospital therapy (88%) survived. Elevated respiratory rate was associated with dying from pneumonia in the LTCF but not in the hospital. Dependent functional status was associated with dying from pneumonia in both sites.

CONCLUSIONS

Many episodes of pneumonia can be managed in the LTCF with oral antibiotics. Because, in the absence of DNH orders, both patient-related and non-patient-related factors are associated with hospital transfer, discussion regarding preferences for hospitalization should occur prior to the development of an acute illness. A high respiratory rate may be a good marker for those LTCF patients requiring hospitalization. Dependent functional status may be a good marker for those LTCF patients unlikely to benefit from hospital transfer.

Critical care for the elderly patient

Elderly individuals will continue to make up a major portion of patients requiring critical care. Age and chronic disease-related factors blunt the reserves with which the elderly can meet the demands of critical surgical illness. The clinician must remain vigilant to subtle changes in the patient's course which may indicate a developing complication and must pay attention to all the details of comprehensive critical care management. With careful attention and timely physiologic support, the elderly patient has as good a chance of surviving as a similarly ill younger patient, although his or her course may be more prolonged. The priorities are the same. Thus, the primary disease must be addressed: necrotic tissue débrided, pus drained, wounds closed, fractures set. Cardiopulmonary performance (oxygen delivery) must be maintained sufficiently to meet the heightened oxygen needs associated with critical illness. This may require invasive hemodynamic monitoring and pharmacologic support. Gas exchange in the lungs must be maintained without compromising cardiovascular function or exhausting the patient. Patients should be kept warm, pain free, and calm. Intravascular volume and the composition of the extracellular fluid must be maintained. Nutritional support should be provided early in amounts sufficient to meet the patient's basal nutritional requirements and increased needs associated with the critical illness. If at all possible, some or all of this nutritional support should be provided via the gastrointestinal tract. The use of specialized nutrients or of agents designed to minimize the catabolism of critical illness or to enhance anabolism is an area of active investigation. The indications for these therapeutic strategies in the elderly should become clearer in the years ahead.

The use of intramuscular cefoperazone versus intramuscular ceftriaxone in patients with nursing home-acquired pneumonia

OBJECTIVE

To compare the efficacy and safety of intramuscular cefoperazone and intramuscular ceftriaxone in the treatment of nursing home-acquired pneumonia in the nursing home setting.

DESIGN

A randomized clinical trial.

SETTING

Skilled nursing wards at the Veterans Home of California.

PATIENTS

104 residents of skilled nursing wards, aged 65 years or older.

INTERVENTIONS

Intramuscular administration of either cefoperazone or ceftriaxone.

MEASUREMENTS

The variables analyzed for baseline comparability were demographics (age, sex), clinical variables (duration in nursing home; presence of sputum, fever, cough, or leukocyte count), and clinical symptoms and signs. Efficacy was assessed by days of therapy, final maximum temperature, and clinical and bacteriological response.

RESULTS

Fifty residents received cefoperazone, 1 gm every 12 hours, intramuscularly. Fifty-four residents received ceftriaxone, 1 gm every 24 hours, intramuscularly. The total duration of treatment was scheduled for 10 days. Clinical cure was seen in 45 (90%) of the cefoperazone treatment group and 51 (94%) of the ceftriaxone treatment group, with a mean duration of therapy of 10.30 and 9.90 days, respectively. Satisfactory sputum specimens were collected in 71% of the treated residents; the most common isolate was Streptococcus pneumoniae, followed by Haemophilus influenzae and Staphylococcus aureus, respectively. The overall mortality was 4.5% at long-term follow-up. Both agents were well tolerated and no therapy was discontinued due to intramuscular pain or abnormal laboratory values.

CONCLUSIONS

Intramuscular cefoperazone and intramuscular ceftriaxone are safe and effective in the treatment of nursing home-acquired pneumonia. The clinical outcomes in both treatment groups support their use within this select population without the need for transferring the patient to an acute care hospital. Clinical studies are needed to evaluate the impact of such therapy on the control of health care expenditures within the nursing home facility.

Comparison of vancomycin pharmacokinetics in hospitalized elderly and young patients using a Bayesian forecaster

Limited data have been published that compare the pharmacokinetic parameters of vancomycin in elderly versus young patients. This study was designed to assess vancomycin pharmacokinetics in 148 elderly (> or = 60 years of age) and 140 young (18-59 years of age) hospitalized infected patients. Serum vancomycin concentrations were determined using fluorescence polarization immunoassay. Serum concentration-versus-time data were fitted to a two-compartment Bayesian forecasting program. Elderly versus young vancomycin pharmacokinetic parameters derived were as follows (patients with serum creatinine < or = 1.5 mg/dL); mean +/- standard deviation terminal disposition half-life (t1/2) of 17.8 +/- 11.8 versus 7.5 +/- 6.7 hours, respectively, P < .05; volume of distribution (Vz) of 74.2 +/- 32.3 versus 67.0 +/- 30.7 L, respectively, P = .16; and total body clearance (CL) of 0.71 +/- 0.41 versus 1.22 +/- 0.50 mL/min/kg, respectively, P < .05. Comparing subjects with normal serum creatinine values (< or = 1.5 mg/dL), the elderly required smaller daily doses as compared with the young group to maintain target peak and trough vancomycin serum concentrations (18.2 +/- 5.8 verus 25.2 +/- 7.8 mg/kg/day, P < .05). Stepwise multiple regression models for the pharmacokinetic parameters were developed to assess the predictive power of age, controlling for the effects of gender, total body weight, serum creatinine, and creatinine clearance. Age was consistently an independent and significant predictor of t1/2, Vz, and CL. These data demonstrate that elderly patients exhibit significant differences in vancomycin pharmacokinetic parameters compared with young patients and constitute a patient population in need of individualized vancomycin dosing due to substantial heterogeneity in physiologic and pharmacokinetic parameters.

Difficulty in predicting bacteremia in elderly emergency patients

STUDY OBJECTIVES

To characterize the clinical presentation and identify factors predictive of bacteremia in elderly patients.

DESIGN

Retrospective review of emergency department charts, hospital records, and microbiology reports.

SETTING

Community teaching hospital with annual ED census of 65,000 adults.

PARTICIPANTS

Seven hundred fifty elderly patients (aged 65 to 99 years) who were evaluated by the emergency physician, had blood cultures obtained in the ED, and were hospitalized with a suspected infectious process during a 12-month period.

MEASUREMENTS

Records were analyzed for demographic information, underlying diseases, clinical presentation, laboratory findings, sources of infection, and causative organisms. Using contingency tables, 79 patients with positive blood cultures were compared with a random sample of 136 patients with sterile blood cultures to identify clinical variables significantly (P less than .05) associated with bacteremia. Logistic regression analysis was performed with significant factors to develop a model to predict bacteremia. Sensitivity, specificity, and predictive values were calculated for the model.

MAIN RESULTS

The prevalence of bacteremia was 10.6%. Escherichia coli was the most commonly isolated pathogen (29% of cases), and the urinary tract was the most common source of infection (44.3% of cases). Logistic regression analysis showed that altered mental status (odds ratio, 2.88; 95% confidence interval [Cl], 1.52 to 5.50), vomiting (odds ratio, 2.63; 95% Cl, 1.16 to 6.15), and WBC band forms of more than 6% (0.06) (odds ratio, 3.50; 95% Cl, 1.58 to 5.27) were independent predictors of bacteremia. The presence of at least one of these three factors had a sensitivity of 0.85 (95% Cl, 0.75 to 0.92) and a specificity of 0.46 (95% Cl, 0.38 to 0.55) for predicting bacteremia in the study group. The positive predictive value was 0.16 (95% Cl, 0.12 to 0.19) and the negative predictive value was 0.96 (95% Cl, 0.94 to 0.98) for the ED patient group that met inclusion criteria.

CONCLUSION

Elderly patients fail to manifest identifiable clinical features indicative of bloodstream infection. The sensitivity and specificity of the best statistical model for identifying bacteremic elderly patients suggest that clinical indicators alone are unreliable predictors of bacteremia in the geriatric ED population studied.

Infection in the elderly: studies with lomefloxacin

Results of trials of lomefloxacin (400 mg once daily) in elderly patients with uncomplicated urinary tract infections, complicated urinary tract infections, acute bacterial exacerbations of chronic bronchitis, and as prophylaxis for transurethral surgical procedures (400 mg single dose) have been analyzed. In patients greater than or equal to 65 years of age with uncomplicated urinary tract infections, the bacterial eradication rate for lomefloxacin was 100%. In patients with complicated urinary tract infections, the bacterial eradication rate for lomefloxacin (92.2%) was statistically superior to comparator agents (84.9%, p = 0.012). In elderly patients with acute exacerbations of chronic bronchitis caused predominantly by gram-negative pathogens, lomefloxacin eradicated 85.2% of pathogens versus 73.8% for amoxicillin (p = 0.004). Lomefloxacin was 98% effective as a prophylactic agent in transurethral surgery. The bacteriologic and clinical efficacy of lomefloxacin was similar in young and elderly groups of patients. Lomefloxacin appears to be as effective as the comparator drugs in both young and elderly patients.

Pressure ulcers: critical considerations in prevention and management

Pressure ulcer development is a serious problem occurring predominately among elderly persons, who are confined to bed or chair. Factors associated with pressure ulcer development include: cerebrovascular accident, impaired nutritional intake, fecal incontinence, lymphocytopenia and a high comorbidity score. Implementation of preventative measures, such as: in-depth assessment for mobility, a pressure relieving device combined with adequate repositioning, thorough evaluation for nutritional status and urinary incontinence, significantly reduce pressure ulcer incidence. If the pressure ulcer is a partial thickness (Stage II) wound, the causative factors are probably friction and/or moisture. If the ulcer is full thickness (Stage III, IV) it is secondary to pressure and/or shearing forces. The development of wound infection is the most common complication. Osteomyelitis is not an uncommon occurrence and must be initially ruled out in all full thickness pressure ulcers. Surgical debridement of necrotic tissue is necessary prior to further treatment and /or assessments. Cultures and antibiotic therapy are indicated only upon evidence of infection (erythema, edema, cellulitis, osteomyelitis, leukocytosis, bandemia or fever). Topical pharmacologic agents may be used to prevent or treat infection but must be carefully controlled to avoid such adverse effects as toxicity to the wound, allergic reaction and development of resistant pathogens. Proper use of occlusive dressings increase patient comfort, enhance healing, decrease the possibility of infection, save time and reduce costs. A patient presenting an ulcer which fails to improve, or due to its size will take a great deal of time to heal, should be evaluated for surgical closure.