Antimicrobials In Patients Research Articles

332 Impact of Emergency Department Clinical Pharmacist Response to an Automated Electronic Notification System on Timing and Appropriateness of Antimicrobials in Severe Sepsis or Septic Shock in the Emergency Department

Study Objectives: To determine the effect of an emergency department (ED) clinical pharmacist response to an automated electronic notification system on the timing and appropriateness of antimicrobials in patients with severe sepsis or septic shock in the ED. Methods: The study was conducted in an ED at a tertiary care academic medical center with 80,000 visits annually. This was a prospective interventional cohort (01/21/2010 - 006/20/2010) study with a historical control cohort (01/21/2009-06/20/2009). Potentially eligible patients were identified by an electronic notification system. The electronic notification system criteria/algorithm were previously validated in our ED to detect potential patients with severe sepsis and septic shock. The prospective cohort was identified by application of the electronic notification system criteria via radio page in real-time. The historical control cohort was identified by applying the electronic notification system criteria retrospectively to the ED electronic tracking board which retains and stores all patient information for all ED visits on a Microsoft SQL Server 2005 database. Patients were eligible for the study if they met electronic notification system criteria, had severe sepsis or septic shock (per Surviving Sepsis Campaign Guidelines) and presented to the ED while the pharmacist was present (approximately 80 hours/week). A radio page was sent to an ED clinical pharmacist when a patient met electronic notification system criteria. The pharmacist evaluated the patient for the presence of severe sepsis or septic shock, recommended empiric antimicrobials, and facilitated their procurement and administration. Primary outcome measures were: 1) time from ED room assignment to appropriate antimicrobial administration; and 2) proportion of patients with appropriate antimicrobials administered within 3 hours of ED room assignment. Appropriate antimicrobials were defined as having activity against any isolated pathogen or following national or institutional guidelines in culture negative patients. Determination of severe sepsis or septic shock in all electronic notification system patients and assessment of appropriateness of antimicrobials was done by chart review after completion of the study by blinded reviewers. Results: The electronic notification system was triggered 1232 and 1202 times during the intervention and control cohort study periods, respectively. Of these, 160 (13%) and 143 (12%) patients met inclusion criteria in the intervention and control groups respectively. Baseline demographic characteristics and ED length of stay were similar between groups. There was no significant difference in mean time from ED arrival to meeting electronic notification system criteria. Patients in the intervention group had a shorter median time to appropriate antimicrobial administration than in the control group (173 [IQR 182] versus 217IQR 301] minutes, P = 0.03). There were significantly more patients who received appropriate antimicrobials in the ED (73% versus 61% P=0.03). The proportion of patients who received appropriate antimicrobials within 3 hours of ED presentation (room time) was higher in the intervention group compared to controls (47% versus 35%, P=0.048). Conclusion: An ED pharmacist response to an automated electronic notification system resulted in faster time to appropriate antimicrobial administration and a higher rate of appropriate empiric antimicrobial use within 3 hours of presentation. This method is one means of improving the care of patients with severe sepsis and septic shock in the ED.

The impact of systemic fungal infection in patients with perforated oesophagus.

INTRODUCTIONPerforated oesophagus is a surgical emergency with significant morbidity and mortality. Systemic fungal infection represents a poor response to the magnitude of the insult, which adds significantly to the risk of morbidity and mortality in these patients. We reviewed our experience with this group of patients over a six-year period in a tertiary referral centre.METHODSA retrospective clinical review was conducted of patients who were admitted following a ruptured oesophagus over a period of six years (January 2002 – January 2008).RESULTSWe had 27 admissions (18 men and 9 women) following an isolated perforated oesophagus to our unit. The median patient age was 65 years (range: 22–87 years). The majority (n=24,89%) presented with spontaneous perforations (Boerhaave’s syndrome) and three (11%) were iatrogenic. Fungal organisms, predominantly Candida albicans, were positively cultured in pleural or blood samples in 16 (59%) of the 27 patients. Fourteen patients grew yeasts within the first seven days while two showed a delayed growth after ten days. Overall mortality was 5 out of 27 patients (19%). There was no mortality among the group that did not grow yeasts in their blood/pleural fluid while mortality was 31% (5/16) in the group with systemic fungal infection (p<0.001). A positive fungal culture was also associated with increase ventilation time, intensive care unit stay and inpatient hospital stay but not an increased rate of complications.CONCLUSIONSSystemic fungal infection in patients with a ruptured oesophagus affects a significant proportion of these patients and carries a poor prognosis despite advanced critical care interventions. It may represent a general marker of poor host response to a major insult but can add to mortality and morbidity. It is worth considering adding antifungal therapy empirically at an early stage to antimicrobials in patients with an established diagnosis of a perforated oesophagus.

Sputum colour and bacteria in chronic bronchitis exacerbations: a pooled analysis

We examined the correlation between sputum colour and the presence of potentially pathogenic bacteria in acute exacerbations of chronic bronchitis (AECBs). Data were pooled from six multicentre studies comparing moxifloxacin with other antimicrobials in patients with an AECB. Sputum was collected before antimicrobial therapy, and bacteria were identified by culture and Gram staining. Association between sputum colour and bacteria was determined using logistic regression. Of 4,089 sputum samples, a colour was reported in 4,003; 1,898 (46.4%) were culture-positive. Green or yellow sputum samples were most likely to yield bacteria (58.9% and 45.5% of samples, respectively), compared with 18% of clear and 39% of rust-coloured samples positive for potentially pathogenic microorganisms. Factors predicting a positive culture were sputum colour (the strongest predictor), sputum purulence, increased dyspnoea, male sex and absence of fever. Green or yellow versus white sputum colour was associated with a sensitivity of 94.7% and a specificity of 15% for the presence of bacteria. Sputum colour, particularly green and yellow, was a stronger predictor of potentially pathogenic bacteria than sputum purulence and increased dyspnoea in AECB patients. However, it does not necessarily predict the need for antibiotic treatment in all patients with AECB.

Comparative Efficacy and Safety of Various Anti-Microbials in Patients of Acute Rhinosinusitis at Tertiary-Care Hospital in Uttarakhand (UK)

To compare the efficacy of gatifloxacin, azithromycin with amoxicillin as positive control for the treatment of Acute rhinosinusitis (ARS). To monitor adverse drug reaction profile of amoxicillin, azithromycin and gatifloxacin in patient of ARS. An open randomized trial of comparative efficacy and safety of amoxicillin, azithromycin and gatifloxacin in patients with ARS. Patients were randomized into three groups as under: group 1: patients on oral amoxicillin 500mg TDS for 10days; group 2: patients on oral azithromycin 500mg OD for 5days; group 3: patients on oral gatifloxacin 400mg OD for 10days. Patients were evaluated for signs and symptoms at day 1, day 7 (for group 2), on day 12 (for group 1, 3) as primary end points and 28days after post therapy as secondary end point. All the three antimicrobial drugs i.e., amoxicillin, azithromycin and gatifloxacin were effective in reducing symptoms of acute sinusitis on visual analogue scale scoring. Azithromycin showed significant improvement radiographically on day 7 (P<0.01) and on day 35 (P<0.01). Gatifloxacin elicited very highly significant improvement radiographically on day 40 (P<0.001) and significant improvement on day 12 (P<0.01) when compared with amoxicillin. Azithromycin, the ketolide was associated with lesser adverse effects as compared to amoxicillin. All the three antimicrobial drugs i.e., amoxicillin, azithromycin and gatifloxacin were effective in reducing symptoms of acute sinusitis on visual analogue scale scoring. Gatifloxacin was found to be most effective drug both in terms of improvement in signs and symptoms on visual analogue scale and radiographic scoring and was associated with least adverse events in comparison to rest of two drugs under study.

Rational Use of Antimicrobials in Patients with Severe Acute Pancreatitis

Infectious complications in severe acute pancreatitis are associated with considerable morbidity and mortality. The course of the disease is often protracted, and patients often stay in the hospital for several weeks. Diagnosis of infected pancreatic necrosis is difficult, and the treatment consists of source control and antibiotic treatment. Antibiotic use should be rational in terms of a rational indication, a rational spectrum, and a rational duration. Prophylactic antibiotics are not effective in reducing the incidence of (peri)-pancreatic infection in patients with severe disease (or even documented necrotizing pancreatitis). The only rational indication for antibiotics is documented infection. The spectrum of empirical antibiotics should include both aerobic and anaerobic gram-negative and gram-positive microorganisms. Also, fungal infections are often present in these patients, and antifungal coverage or even prophylaxis should be considered, especially if multiple risk factors for invasive candidiasis are present. Although initiation of antibiotics may be a difficult decision, stopping antibiotic therapy often proves to be even more difficult. Currently, no tools are available to guide antimicrobial treatment. Antibiotic use is only effective if proper source control has been established.

Analysis of the prophylactic use of antimicrobials in patients undergoing type-Ⅰ incision operation

Analysis of the prophylactic use of antimicrobials in patients undergoing type-Ⅰ incision operation

Treatment of acute bacterial exacerbations of chronic bronchitis

Background: Controversies persist regarding the optimal management of patients with acute exacerbations of chronic bronchitis (AECB). Objective: To evaluate the available evidence on relevant issues, namely the need for administering antimicrobials in patients with AECB, the identification of the subgroup of patients with AECB needing antibiotics, the antimicrobial regimen of choice and its optimal duration, the existence of new agents, and the value of non-antimicrobial regimens for AECB. Methods: Data from various sources of evidence, including recent relevant meta-analyses, were appraised. Conclusion: Administration of antimicrobial agents, combined with bronchodilators and systemic corticosteroids, is warranted in approximately half of AECBs (i.e., in bacterial exacerbations) to achieve a survival benefit. Simple clinical parameters, mainly sputum purulence, and biomarkers, such as procalcitonin, are useful in identifying patients requiring antibiotics. Advanced antibiotics (quinolones, macrolides, or amoxicillin/clavulanic acid) are more effective than ‘old’ antibiotics in AECB; regimens of short duration (for 5 days) are preferred. There is no difference between several classes of advanced antibiotics regarding their short-term effectiveness; however, quinolones are associated with better long-term outcomes than macrolides. Newer quinolones and new formulations of macrolides enrich clinicians' armamentarium against AECB.

Stool Cultures and Antimicrobial Prescriptions Related to Infectious Diarrhea: Carpenter LR, Pont SJ, Cooper WO, et al. J Infect Dis 2008;197:1709–12

Acute diarrheal disease commonly precipitates a visit to the Emergency Department or urgent care clinic. The authors investigated the use of stool culture to guide prescription of antimicrobials in patients with acute diarrhea. The authors performed a retrospective cohort study of people aged < 65 years enrolled in a state-run managed care organization. A total of 315,828 diarrheal episodes were identified with billing codes. Of these, 15,820 (5.0%) were evaluated with stool culture, whereas 32,949 (10.4%) received a prescription for antimicrobials.

Timing of antibiotics in CAP

PurposeTimely administration of antimicrobials in patients with community‐acquired pneumonia is now a standard of care. The purpose of this paper is to present a large observational study to understand the issues that result in a delay in the administration of antibiotics to patients with community‐acquired pneumoniaDesign/methodology/approachThis prospective study involved all six hospitals in the Edmonton area: patients were enrolled at the time of hospitalization if they were adults aged ≥17 years with a clinical presentation consistent with community‐acquired pneumonia. A retrospective chart review was performed to determine the reasons why it took more than eight hours to administer the first dose of antibiotics.FindingsThe paper finds that of all 3,394 hospitalized patients, 646 (19.0 percent) received antibiotics over four hours after admission to the emergency department and in most instances the delay was more than 12 hours. A total of 30 percent of the delays were justifiable – 17 percent due to diagnostic indecision and 13 percent due to recent receipt of an antibiotic at home or at another institution prior to transfer. All the other delays were unnecessary and easily correctable. In this paper the data indicate that only 5.6 percent of 3,394 patients had an adequate reason for delay in antibiotic administration. Thus a reasonable target for timely administration of antibiotics is at least 90 percent of the patient population.Originality/valueThe strengths of this study lie in its large number of patients, inclusiveness and real world context.

Adverse Cutaneous Reactions to Antimicrobials in Patients with Human Immunodeficiency Virus Infection

Adverse reactions to medication are significant contributors to morbidity and mortality in patients with human immunodeficiency virus (HIV) infection. Cutaneous events not only constitute a significant portion of these reactions, they may also herald developing systemic reactions such as hemato-, nephro-, and hepatotoxicity. The identification of cutaneous adverse reactions and drug culprits and the proper management of reactions are of paramount importance for these patients. This review focuses specifically on adverse cutaneous reactions to antimicrobials that are commonly used in the management of patients with HIV infection.

Clinical Scoring System for the Prediction of Target Site Penetration of Antimicrobials in Patients with Sepsis

The present study investigated the usefulness of routinely employed scoring systems in predicting tissue penetration of antimicrobials. In addition, a novel, easy to use scoring system was designed for the estimation of tissue penetration of antimicrobials in patients with sepsis. Tissue pharmacokinetics were assessed in skeletal muscle and subcutaneous adipose tissue by use of the microdialysis technique in 34 patients with sepsis. Tissue penetration of antimicrobials was retrospectively determined by the ratios of the area under the concentration-time curves (AUC) in soft tissues (AUCtissue) to the AUC in plasma (AUCplasma). Mortality and sepsis scores currently used in intensive care were consecutively calculated and correlated with the AUCtissue:AUCplasma ratio. Single laboratory and clinical parameters showing the highest correlation with tissue penetration were identified and used in the novel Tissue Penetration Prediction Score (TPPS). The currently used scoring systems Simplified Acute Physiology Scores 3 (r=-0.33, p=0.006), Acute Physiology and Chronic Health Evaluation III (r=-0.27, p=0.03) and Sepsis-Related (or Sequential) Organ Failure Assessment (r=-0.32, p=0.01) showed significant overall correlations with tissue penetration. However, their predictive power for the concentrations of antimicrobials in muscle tissue was not satisfying. The parameters oxygen saturation, serum lactate concentration and the dose per time unit of norepinephrine (noradrenaline) administered showed the best correlation with tissue penetration and were used in the TPPS. Its overall correlation (r=-0.52, p=0.000007) as well as correlations for the concentrations of antimicrobials in muscle (r=-0.46, p=0.006) and adipose tissue (r=-0.59, p=0.0003) were better than the currently used scoring systems. The TPPS may prove to be a powerful tool for the estimation of antimicrobial tissue penetration at the bedside in septic patients. This score may allow for adequate individual dose adjustment in septic patients. However, this needs to be verified in subsequent prospective clinical trials.

Antibiotic policies in surgery: a consensus paper

An antibiotic policy should review general issues regardng the use of antimicrobials in surgery, rather than deal with articular points of prophylaxis or treatment of specific surical site infections (SSIs). The ever-increasing opportunities or the use of antimicrobials in patients with surgical infecion pose many serious problems. Perhaps the most urgent s the excessive, and inappropriate, use of antibiotics, which ay lead to the emergence of antimicrobial resistance. Since arenteral antimicrobial agents are used most intensively in ospitals, hospital antibiotic policies should seek to minimise ntibiotic resistance.

Symptomatic Treatment of Infections in Patients with Advanced Cancer Receiving Hospice Care

Symptom control is one of the primary goals of hospice care. We prospectively followed patients with advanced cancer receiving outpatient hospice care to determine if the use of antimicrobials for a clinically suspected infection improved infection-related symptoms. During a 24-month period, 1,731 patients with a cancer diagnosis were admitted to a community-based outpatient hospice program. Over 89% of the patients had a Karnofsky performance of ≤60%. Six hundred twenty-three of 1,598 study patients were diagnosed with a total of 685 infections. Six hundred thirty-three of the infections were treated with antimicrobials for a clinically suspected infection. Symptoms were recorded, clinically indicated cultures were obtained, and antimicrobials were instituted at the discretion of the attending physician. Patients were subsequently monitored to determine the effects of antimicrobials on infection-related symptoms. A complete or a partial response of infection-related symptoms was observed in 79% of 265 patients with urinary tract infections, 43% of 221 patients with respiratory tract infections, 46% of 63 patients with oral cavity infections, 41% of 59 patients with skin or subcutaneous infections, and none of 25 patients with bacteremia. Fifty-two of the infections were not evaluable due to refusal of antimicrobials or receipt of less than 72 hours of antimicrobials. Patient survival in this study was not affected by the presence of infection or the use of antimicrobials. Although the use of antimicrobials improved symptoms in the majority of patients with urinary tract infections, symptom control was less successful in infections of the respiratory tract, mouth/pharynx, skin/subcutaneous tissue, or blood. Physicians should be aware of the limitations of the use of antimicrobials in patients with advanced cancer receiving hospice care. Treatment guidelines are proposed emphasizing the importance of patient preferences and the use of symptom control as the major indication for the use of antimicrobials in this patient population.

Symptomatic treatment of infections in patients with advanced cancer receiving hospice care

8069 Background: Symptom control is one of the primary goals of hospice care. We prospectively followed patients with advanced cancer receiving outpatient hospice care to determine if the use of antimicrobials for a clinically suspected infection improved infection related symptoms. Methods: During a 24 month period, 1,731 patients with a cancer diagnosis were admitted to a community based outpatient hospice program. 1,598 patients (median age 63.1 yrs, range 27–89; 50% male) consented to be prospectively monitored for infection related symptoms (cough, disorientation, dyspnea, dysuria, fever, frequency, pain). 89% of the patients had a Karnofsky performance of ≤ 60%. 623 of 1,598 study patients were diagnosed with a total of 685 infections. 633 of the clinically suspected infections were treated with antimicrobials for at least 72 hours. Symptoms were recorded, clinically indicated cultures were obtained, and the choice of antimicrobial was instituted at the discretion of the attending physician. Patients were subsequently monitored to determine the effects of antimicrobials on infection related symptoms. Results: A complete or a partial response of infection related symptoms was observed in 79% of 265 patients with urinary tract infections, 43% of 221 patients with respiratory tract infections, 46% of 63 patients with oral cavity infections, 41% of 59 patients with skin or subcutaneous infections, and none of 25 patients with bacteremia. 52 of the infections were not evaluable due to refusal of antimicrobials or receipt of less than 72 hours of antimicrobials. Patient survival was not affected by the presence of infection or the use of antimicrobials. Conclusions: Although the use of antimicrobials improved symptoms in the majority of patients with urinary tract infections, symptom control was less successful in infections of the respiratory tract, mouth/pharynx, skin/subcutaneous tissue, or blood. There are limitations of the use of antimicrobials in patients with advanced cancer receiving hospice care. Treatment guidelines are proposed emphasizing the importance of patient preferences and the use of symptom control as the major indication for the use of antimicrobials in this patient population. No significant financial relationships to disclose.

Lack of development of new antimicrobial drugs: a potential serious threat to public health

Antimicrobial resistance is threatening the management of infections such as pneumonia, tuberculosis, malaria, and AIDS. In the past, resistance could be handled by development of new drugs active against resistant microbes. However, the pharmaceutical industry has reduced its research efforts in infections; genomics has not delivered the anticipated novel therapeutics; new regulatory requirements have increased costs; antibiotic use in common infections-eg, bronchitis and sinusitis-is questioned; and, compared with other drugs, return on investments is lower for antimicrobials. To avoid a serious threat to public health, academia, biotechnology and pharmaceutical industry, regulators, and healthcare providers must find solutions to this problem. Academia should concentrate on technologies to unlock new drug targets, and industry on drug candidates. In addition, regulators and pharmaceutical companies should agree on new clinical-trial designs so that information on therapeutic efficacy is generated in fewer patients-eg, by studying pharmacodynamics of antimicrobials in patients with defined infections.

Pharmacodynamics of Vancomycin and Other Antimicrobials in Patients with Staphylococcus aureus Lower Respiratory Tract Infections

Vancomycin is commonly used to treat staphylococcal infections, but there has not been a definitive analysis of the pharmacokinetics of this antibacterial in relation to minimum inhibitory concentration (MIC) that could be used to determine a target pharmacodynamic index for treatment optimisation. To clarify relationships between vancomycin dosage, serum concentration, MIC and antimicrobial activity by using data gathered from a therapeutic monitoring environment that observes failures in some cases. We investigated all patients with a Staphylococcus aureus lower respiratory tract infection at a 300-bed teaching hospital in the US during a 1-year period. Clinical and pharmacokinetic information was used to determine the following: (i) whether steady-state 24-hour area under the concentration-time curve (AUC24) divided by the MIC (AUC24/MIC) values for vancomycin could be precisely calculated with a software program; (ii) whether the percentage of time vancomycin serum concentrations were above the MIC (%Time>MIC) was an important determinant of vancomycin response; (iii) whether the time to bacterial eradication differed as the AUC24/MIC value increased; (iv) whether the time to bacterial eradication for vancomycin differed compared with other antibacterials at the same AUC24/MIC value; and (v) whether a relationship existed between time to bacterial eradication and time to significant clinical improvement of pneumonia symptoms. The median age of the 108 patients studied was 74 (range 32-93) years. Measured vancomycin AUC24/MIC values were precisely predicted with the A.U.I.C. calculator in a subset of our patients (r2 = 0.935). Clinical and bacteriological response to vancomycin therapy was superior in patients with higher (> or = 400) AUC24/MIC values (p = 0.0046), but no relationship was identified between vancomycin %Time>MIC and infection response. Bacterial eradication of S. aureus (both methicillin-susceptible and methicillin-resistant) occurred more rapidly (p = 0.0402) with vancomycin when a threshold AUC24/MIC value was reached. S. aureus killing rates were slower with vancomycin than with other antistaphylococcal antibacterials (p = 0.002). There was a significant relationship (p < 0.0001) between time to bacterial eradication and the time to substantial improvement in pneumonia score. Vancomycin AUC24/MIC values predict time-related clinical and bacteriological outcomes for patients with lower respiratory tract infections caused by methicillin-resistant S. aureus.

Short-Course, Low-Dose Oral Betamethasone as an Adjunct in the Treatment of Acute Infective Sinusitis

To assess the effect of a short course of low-dose oral corticosteroid used as an adjunct to antimicrobials in patients with acute infective sinusitis. Double-blind, randomised, placebo-controlled study including 42 patients with a clinical diagnosis of acute infective sinusitis. The study was performed at three primary healthcare sites in South Africa during the period January-November 2003. Two equal groups received either betamethasone 1mg orally (n = 21; the treatment group) or placebo tablets (n = 21; the placebo group) once a day in the morning for five consecutive days. All patients received amoxicillin-clavulanic acid 625mg orally, three times daily for 5 days. Patients rated symptoms on a daily symptom score card for 5 days and were examined by the investigator at diagnosis (day 0) and on the second visit (day 6). Headache, facial pain, nasal congestion and dizziness improved significantly from baseline in the treatment group compared with the placebo group over 5 days of treatment (p = 0.028, p </= 0.047, p </= 0.04 and p </= 0.051, respectively). Percussion tenderness improved significantly (p = 0.049) and clearance of purulent secretions almost reached significance (p = 0.058) in the treatment group compared with the placebo group. This study suggests a benefit of oral corticosteroid added to antimicrobial treatment of acute sinusitis and documents the first successful use of a short course of low-dose oral corticosteroid in patients with acute infective sinusitis.

Frequency of sensitization to antimicrobials in patients with atopic eczema compared with nonatopic individuals: analysis of multicentre surveillance data, 1995-1999.

Atopic eczema, a multifactorial disease, is influenced by bacterial factors, particularly Staphylococcus aureus. Consequently, treatment includes therapy with antibiotics and nonantibiotic antimicrobials. In our study the sensitizing potential of some topical antimicrobials was investigated by comparing proportions sensitized to various antibiotics and antiseptics between patients with current or past atopic eczema, and patients who had never had atopic eczema. Data of all patients patch tested in the Departments of Dermatology participating in the Information Network of Departments of Dermatology (IVDK) between 1995 and 1999 were analysed. Patients with a current leg ulcer or stasis dermatitis that might cause a confounding effect were excluded. Controlling for the additional confounding effect of sex and particularly age, we did not find that patients with atopic eczema had a generally higher risk compared with nonatopic individuals. While the risk of sensitization should always be considered when applying topical therapy, our data-within the methodological limitations of this type of study-would not support a very restrictive use of these agents in the management of atopic eczema.

A prospective observational study of the effect of penicillin skin testing on antibiotic use in the intensive care unit.

Patients with penicillin allergy admitted to the intensive care unit (ICU) frequently receive non-beta-lactam antimicrobials for the treatment of infection. The use of these antimicrobials, more commonly vancomycin and fluoroquinolones, is associated with the emergence of multidrug-resistant infections. The penicillin skin test (PST) can help detect patients at risk of developing an immediate allergic reaction to penicillin and those patients with a negative PST may be able to use a penicillin antibiotic safely. We determined the incidence of true penicillin allergy, the percentage of patients changed to a beta-lactam antimicrobial when the test was negative, the safety of the test, and the safety of administration of beta-lactam antimicrobials in patients with a negative test. Skin testing was performed using standard methodology. One hundred patients admitted to 4 ICUs were prospectively studied; 58 of them were male. The mean age was 63 years. Ninety-six patients had the PST: one was positive (1.04%), 10 (10.4%) were nondiagnostic, and 85 (88.5%) were negative. Of the 38 patients who received antimicrobials for therapeutic reasons, 31(81.5%) had the antibiotic changed to a beta-lactam antimicrobial after a negative reading versus 7 patients of the 57 (12%) who had received a prophylactic antimicrobial (P < .001). No adverse effects were reported after the PST or after antimicrobial administration. The PST is a safe, reliable, and effective strategy to reduce the use of non-beta-lactam antimicrobials in patients who are labeled as penicillin allergic and admitted to the ICU.

Lectura interpretada del antibiograma: ¿ejercicio intelectual o necesidad clínica?

Clinical categorisation of susceptibility testing results according to criteria established by different committees is daily performed in clinical microbiology laboratories. By this process clinicians can predict the therapeutic success of antimicrobial treatment in patients infected with susceptible microorganisms. In addition, microbiology laboratories that include a suitable number of antimicrobial agents in susceptibility tests can perform interpretive reading of the antibiogram. With this approach, resistance phenotypes are recognized and allow microbiologist: a) detection of mechanisms of resistance, including low levels of expression; b) modification of clinical classifications that are inconsistent with the inferred resistance mechanism; and c) inference of susceptibility values for antimicrobials that are not included in the antibiogram. In the laboratory, this approach facilitates quality control and validation of susceptibility results. Moreover, it increases the value of the results obtained because new mechanisms of resistance can be characterized and the epidemiology of resistance can be established. From the clinical point of view, this approach contributes to improving the adequacy of treatment (since it is useful for predicting therapeutic failure with the use of antimicrobials in patients with infections due to resistant microorganisms) and to controlling and defining antimicrobial policies. Despite the growing complexity of resistance mechanisms, which makes interpretative reading of the antibiogram difficult, this process should be incorporated into routine practice in microbiology laboratories. Interpretive reading of antibiograms is clinically necessary and not simply a intellectual exercise.