Inadequate antimicrobial treatment of infections: a risk factor for hospital mortality among critically ill patients

Antibiotic resistance in the intensive care unit

The increase in antibiotic resistance over the past 10 years can be traced to several factors. This includes exogenous transmission of bacteria, usually by hospital personnel. The use of potent antibiotics also can select for resistant bacteria initially present in low quantities. Strategies to reduce antibiotic resistance can be tailored to specific outbreaks in a given ICU. General strategies for reducing antibiotic resistance, on the other hand, include varying the agents used in the ICU over time. Reduction of the duration of therapy may prove to be another method of reducing antibiotic resistance.

Antimicrobial resistance in the intensive care unit: understanding the problem

Antimicrobial resistance is a problem that affects healthcare delivery around the globe. Factors associated with antimicrobial resistance include overuse or misuse of antimicrobial agents, immunosuppressed patients, and increased technology. Cellular mechanisms of antimicrobial resistance include the decreased uptake of a drug, efflux of the drug, enzymatic inactivation, and alterations in the antimicrobial target site. New treatment options are currently available for resistant organisms. Therapeutic strategies such as antibiotic control policies and antibiotic "cycling" have been proposed as methods for minimizing the emergence of more resistant organisms. Little evidence is available to indicate that these strategies are effective in limiting the emergence of resistance. Clinicians are urged to be judicious in their use and choice of antimicrobials.

Clinical importance of delays in the initiation of appropriate antibiotic treatment for ventilator-associated pneumonia

STUDY OBJECTIVES

To determine the influence of initially delayed appropriate antibiotic treatment (IDAAT) on the outcomes of patients with ventilator-associated pneumonia (VAP).

SETTING

Medical ICU of Barnes-Jewish Hospital, St. Louis, a university-affiliated urban teaching hospital.

PATIENTS

One hundred seven consecutive patients receiving mechanical ventilation and antibiotic treatment for VAP.

INTERVENTIONS

Prospective patient surveillance and data collection.

MEASUREMENTS AND RESULTS

All 107 patients eventually received treatment with an antibiotic regimen that was shown in vitro to be active against the bacterial pathogens isolated from their respiratory secretions. Thirty-three patients (30.8%) received antibiotic treatment that was delayed for >or= 24 h after initially meeting diagnostic criteria for VAP. These patients were classified as receiving IDAAT. The most common reason for the administration of IDAAT was a delay in writing the antibiotic orders (n = 25; 75.8%). The mean time (+/- SD) interval from initially meeting the diagnostic criteria for VAP until the administration of antibiotic treatment was 28.6 +/- 5.8 h among patients classified as receiving IDAAT, compared to 12.5 +/- 4.2 h for all other patients (p < 0.001). Forty-four patients (41.1%) with VAP died during their hospitalization. Increasing APACHE (acute physiology and chronic health evaluation) II scores (adjusted odds ratio, 1.13; 95% confidence interval, 1.09 to 1.18; p < 0.001), presence of malignancy (adjusted odds ratio, 3.20; 95% confidence interval, 1.79 to 5.71; p = 0.044), and the administration of IDAAT (adjusted odds ratio, 7.68; 95% confidence interval, 4.50 to 13.09; p < 0.001) were identified as risk factors independently associated with hospital mortality by logistic regression analysis.

CONCLUSION

These data suggest that patients classified as receiving IDAAT are at greater risk for hospital mortality. Clinicians should avoid delaying the administration of appropriate antibiotic treatment to patients with VAP in order to minimize their risk of mortality.

Nosocomial bacteremia caused by antibiotic-resistant gram-negative bacteria in critically ill patients: clinical outcome and length of hospitalization

Population characteristics and outcomes were retrospectively compared for critically ill patients with nosocomial bacteremia caused by antibiotic-susceptible (AB-S; n=208) or antibiotic-resistant (AB-R; n=120) gram-negative bacteria. No significant differences in severity of illness and comorbidity factors were seen between groups. Patients with bacteremia caused by AB-R strains had a longer hospitalization before the onset of the bacteremia. The in-hospital mortality for patients with bacteremia caused by AB-S strains was 41.8%; for patients infected with AB-R strains, it was 45.0% (P=.576). A multivariate survival analysis demonstrated that older age (P=.009), a high-risk source of bacteremia (abdominal and lower respiratory tract; P=.031), and a high acute physiology and chronic health evaluation II-related expected mortality (P=.032) were independently associated with in-hospital mortality (P<.05). Antibiotic resistance in nosocomial bacteremia caused by gram-negative bacteria does not adversely affect the outcome for critically ill patients.

Recent clinical evidence of the efficacy and safety of thiamphenicol glycinate acetylcysteinate and thiamphenicol glycinate

Thiamphenicol is a broad-spectrum antimicrobial agent active against penicillin-resistant Streptococcus pneumoniae, Staphylococcus aureus VISA strains, most methicillin-resistant isolates and atypical pathogens such as Mycoplasma pneumoniae and Chlamydia pneumoniae). Thiamphenicol is present as glycinate hydrochloride (TG) and glycinate acetylcysteinate (TGA) esters in the parenteral and aerosol dosage form. This multicenter, double-blind, randomized clinical trial aimed to evaluate the efficacy and tolerability of aerosol administration of TGA, compared to TG, in the treatment of acute and/or exacerbated infections of the respiratory tract. Results showed that both treatments ameliorated the symptoms (frequency and severity of cough, difficulty in expectoration) associated with the evaluated pathologies, i.e. tracheobronchitis, acute and exacerbated chronic bronchitis. The investigators rated both treatments Good or Very Good in 90% of patients at the end of treatment, with "Very Good" for patients treated with TGA (37%) compared to 28% of patients treated with TG. Both treatments were well tolerated with fewer than 5% of patients experiencing an adverse event.

Linezolid versus vancomycin for the treatment of methicillin-resistant Staphylococcus aureus infections

Linezolid, the first available member of a new antibiotic class, the oxazolidinones, is broadly active against gram-positive bacteria, including drug-resistant strains. In this randomized, open-label trial, hospitalized adults with known or suspected methicillin-resistant Staphylococcus aureus (MRSA) infections were treated with linezolid (600 mg twice daily; n=240) or vancomycin (1 g twice daily; n=220) for 7-28 days. S. aureus was isolated from 53% of patients; 93% of these isolates were MRSA. Skin and soft-tissue infection was the most common diagnosis, followed by pneumonia and urinary tract infection. At the test-of-cure visit (15-21 days after the end of therapy), among evaluable patients with MRSA, there was no statistical difference between the 2 treatment groups with respect to clinical cure rates (73.2% of patients in the linezolid group and 73.1% in the vancomycin group) or microbiological success rates (58.9% in the linezolid group and 63.2% in the vancomycin group). Both regimens were well tolerated, with similar rates of adverse events.

Ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) continues to complicate the course of 8 to 28% of patients receiving mechanical ventilation (MV). In contrast to infections of more frequently involved organs (e.g., urinary tract and skin), for which mortality is low, ranging from 1 to 4%, the mortality rate for VAP ranges from 24 to 50% and can reach 76% in some specific settings or when lung infection is caused by high-risk pathogens. The predominant organisms responsible for infection are Staphylococcus aureus, Pseudomonas aeruginosa, and Enterobacteriaceae, but etiologic agents widely differ according to the population of patients in an intensive care unit, duration of hospital stay, and prior antimicrobial therapy. Because appropriate antimicrobial treatment of patients with VAP significantly improves outcome, more rapid identification of infected patients and accurate selection of antimicrobial agents represent important clinical goals. Our personal bias is that using bronchoscopic techniques to obtain protected brush and bronchoalveolar lavage specimens from the affected area in the lung permits physicians to devise a therapeutic strategy that is superior to one based only on clinical evaluation. When fiberoptic bronchoscopy is not available to physicians treating patients clinically suspected of having VAP, we recommend using either a simplified nonbronchoscopic diagnostic procedure or following a strategy in which decisions regarding antibiotic therapy are based on a clinical score constructed from seven variables. Selection of the initial antimicrobial therapy should be based on predominant flora responsible for VAP at each institution, clinical setting, information provided by direct examination of pulmonary secretions, and intrinsic antibacterial activities of antimicrobial agents and their pharmacokinetic characteristics. Further trials will be needed to clarify the optimal duration of treatment and the circumstances in which monotherapy can be safely used.

Ciprofloxacin as broad-spectrum empiric therapy--are fluoroquinolones still viable monotherapeutic agents compared with beta-lactams: data from the MYSTIC Program (US)?

Antimicrobial susceptibility data from United States medical centers participating in the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC) surveillance program were analyzed. These results indicate that ciprofloxacin resistance in commonly encountered nosocomial pathogens has reached a level where fluoroquinolones may no longer provide assured empiric monotherapy for serious infections nor provide a spectrum as a co-drug equivalent to aminoglycosides. Local susceptibility testing data must be assessed before fluoroquinolone empiric therapy can be used with confidence.

Ventilator-associated pneumonia. Prevention, diagnosis, and therapy

Ventilator-associated pneumonia remains the nosocomial ICU infection of greatest concern. The authors have summarized the clinical trials that have assessed specific strategies to prevent VAP and the current controversies regarding the diagnosis and therapeutic approach to this condition. Improvements in care of patients who are at risk for or who have developed VAP will depend on the judicious application of this information for individual patients.

Role of serial routine microbiologic culture results in the initial management of ventilator-associated pneumonia

Results of routine microbiologic cultures of specimens obtained before the onset of ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients might help to identify the causative microorganisms and thus to select effective initial antimicrobial therapy. To test this hypothesis, we prospectively studied 125 consecutive VAP episodes for which the causative microorganisms were determined using bronchoscopic techniques. Upon entry into the study, each patient's hospital chart was reviewed and culture results of all previously obtained microbiologic specimens were recorded (mean number +/- SD per patient, 45 +/- 38). A total of 220 microorganisms were cultured at significant concentrations (> or = 10(3)/10(4) colony-forming units [cfu]/ml) from bronchoscopic specimens and considered responsible for pneumonia. Of these 220 organisms, only 73 (33%) were recovered before VAP onset, sometimes from multiple sites in the same patient but mainly from prior respiratory secretion cultures (n = 53). Also previously isolated were 342 organisms that were not responsible for VAP, making prospective identifications of the true pathogens difficult. Among the 102 episodes for which prior respiratory secretion culture results had been obtained (mean time before VAP onset, 8 +/- 9 d), all the organisms ultimately responsible for pneumonia were previously recovered from only 36 (35%) of these specimens. Based on these data, the contribution of routine microbiologic specimens in guiding initial antimicrobial therapy decisions for patients with suspected VAP appears limited.

Economic evaluation of linezolid, flucloxacillin and vancomycin in the empirical treatment of cellulitis in UK hospitals: a decision analytical model

Standard antibiotic treatment of infections has become more difficult and costly due to treatment failure associated with the rise in bacterial resistance. New antibiotics that can overcome such resistant pathogens have the potential for great clinical and economic impact. Linezolid is a new antibiotic that is effective in the treatment of both antibiotic-susceptible and antibiotic-resistant Gram-positive bacterial infections, including those resistant to other available antibiotics. This breadth of activity is unique in existing antibiotics for Gram-positive bacteria and serves as the rationale for exploring the hypothesis that linezolid is an appropriate choice when considering empirical treatment of cellulitis in complicated or compromised patients in the nosocomial setting. A decision-modelling approach was used to compare the predicted first-line treatment efficacy and direct medical costs of linezolid with standard treatment of cellulitis among hospitalized patients. For the purposes of this analysis, standard care is defined along two main pathways: (1) initiating care with intravenous (iv) flucloxacillin, switching to vancomycin if the pathogen is found to be resistant to flucloxacillin, or maintaining flucloxacillin if the pathogen is found susceptible, or when culture and sensitivity analysis is inconclusive; or (2) initiating care with vancomycin, switching to iv flucloxacillin if the pathogen is found susceptible to flucloxacillin, maintaining vancomycin if the infection is found resistant, or when culture and sensitivity are inconclusive. For those patients taking iv flucloxacillin, a switch to oral flucloxacillin was allowed when clinically appropriate. We hypothesized that the cost of care of initiating treatment with linezolid would be less than that for both vancomycin and flucloxacillin in resistance risk ranges typically encountered in UK hospitals. In addition, while the registration trials showed equivalence of linezolid with the comparators in known or suspected methicillin-resistant Staphylococcus aureus (MRSA) and in known or suspected methicillin-susceptible Staphylococcus aureus (MSSA) (vancomycin and oxacillin) respectively, we hypothesized that first-line success rates would be higher in empiric treatment with linezolid. Efficacy data were obtained from recent clinical trials with linezolid and standard treatment, and medical resource utilization was obtained from an expert panel of clinicians who were questioned regarding resistant and susceptible infections separately. UK hospital direct medical costs of treatment were determined using standard costing techniques. Base case analyses assumed a residual 80% unknown pathogen rate after culture and susceptibility based on a physician survey and supported in the literature. The analysis in this model predicts that initiating empirical treatment of cellulitis with linezolid will (1) result in higher overall success rates than flucloxacillin for first-line treatment, regardless of resistance risk and (2) be less costly than initiating treatment with flucloxacillin when the likelihood of a patient being infected by a resistant pathogen is greater than 24.1%. Furthermore, initiating treatment with linezolid is predicted to result in higher overall success rates and be less costly than vancomycin across the entire spectrum of the patients' risk of being infected by a resistant pathogen.

Economic impact and formulary positioning of linezolid: a new anti-Gram-positive antimicrobial

Gram-positive bacteria have emerged as major causes of colonization and serious infection within the nosocomial and increasingly also within the community setting. These infections have significantly contributed to patient morbidity and mortality as well as prolongation of hospital stay, a key determinant of the cost of an episode of infection in hospital. In many countries globally, infections due to methicillin-resistant Staphylococcus aureus (MRSA) are providing the greatest burden of clinical infection, often occurring in vulnerable patients or "high risk" therapeutic settings. Combined with this scenario is the increasing requirement for health care organizations to provide cost-effective health care as well as care that is delivered on evidence-based practice delivered through formularies or guidelines. This article aims to: 1) summarize the key economic considerations pertinent to these multiresistant infections but with an emphasis on MRSA, 2) discuss the current therapeutic options of managing MRSA infections, and 3) discuss the formulary positioning of linezolid by means of outlining its core strengths, weaknesses and the opportunity it provides to hospital infection management.

Mortality rate attributable to ventilator-associated nosocomial pneumonia in an adult intensive care unit: a prospective case-control study

OBJECTIVE

To evaluate the mortality rate attributable to nosocomial ventilator-associated pneumonia in an intensive care unit.

DESIGN

Prospective, matched, risk-adjusted cohort study.

SETTING

A 18-bed adult medical-surgical intensive care unit in a 1,100-bed regional and teaching hospital in France.

PATIENTS

From January 1, 1996, to April 30, 1999, 135 patients who developed nosocomial pneumonia were matched with 135 control patients without nosocomial pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nosocomial pneumonia was identified on the basis of results of distal bronchial samples. The matching process was conducted according to the following primary criteria: cause of admission, indication for ventilatory support, immunologic status, cardiac status, probability of death (+/-5%), Glasgow Coma Scale score (+/-2 points), age (+/-7 yrs), and duration of exposure to risk. When possible, case and control patients were matched according to five secondary criteria: respiratory and alcoholism status before admission, diagnosis categories, surgical procedure or not, and gender. The mortality rates were compared between case and control patients by using the Kaplan-Meier estimate and the log-rank test. The influence of nosocomial pneumonia on mortality rate then was tested by adjusting for the secondary criteria and other possible confounding factors by using the Cox proportional-hazards model. The matching process was successful for 1,080 of 1,080 primary criteria. The crude intensive care unit mortality rate was higher in patients with nosocomial pneumonia than in control patients (41 vs. 14%; p <.0001). In actuarial survival analysis, the probability of intensive care unit death was higher in the case patients (odds ratio = 2.7, 95% confidence interval = 1.8-3.1, p =.028). After adjustment, the occurrence of nosocomial pneumonia remained an independent risk factor of death (odds ratio = 2.1, 95% confidence interval = 1.2-3.6, p =.008). Nosocomial pneumonia attributable to multiresistant microorganisms was significantly associated with death (odds ratio = 2.6, 95% confidence interval = 1.1-5.8, p =.02). The length of intensive care unit stay was higher in case than in control patients (31 +/- 19 vs. 26 +/- 17 days, p <.0001).

CONCLUSIONS

Nosocomial pneumonia is independently associated with death in the intensive care unit. In addition, it increases the length of intensive care unit stay.

Influence of previous exposure to antibiotic therapy on the susceptibility pattern of Pseudomonas aeruginosa bacteremic isolates

Many patients who present with Pseudomonas aeruginosa bacteremia have been previously exposed to antibiotics. To assess whether resistance of bacteremic strains to antipseudomonal antibiotics (piperacillin, ceftazidime, imipenem, ciprofloxacin, or aminoglycosides) is associated with previous exposure to these drugs, a case-control study including 267 cases of P. aeruginosa bacteremia was conducted. Twenty-five percent of the episodes had been preceded by the exposure to an antipseudomonal antibiotic. Eighty-one strains were resistant to at least 1 antibiotic; 186 were susceptible to all drugs. Via univariate analysis, the risks of resistance to ceftazidime and imipenem were found to be significantly associated with previous receipt of these agents. Using multivariate analysis, exposure to any antipseudomonal antibiotic as a monotherapy was found to be associated with an increased risk of subsequent resistance to itself (odds ratio, 2.5; P=.006). Therefore, clinicians should avoid readministering previously prescribed antibiotics when initiating empiric therapies for possible P. aeruginosa bacteremia, especially when they have been given as monotherapies.

Infection control in the ICU

Nosocomial infections (NIs) now concern 5 to 15% of hospitalized patients and can lead to complications in 25 to 33% of those patients admitted to ICUs. The most common causes are pneumonia related to mechanical ventilation, intra-abdominal infections following trauma or surgery, and bacteremia derived from intravascular devices. This overview is targeted at ICU physicians to convince them that the principles of infection control in the ICU are based on simple concepts and that the application of preventive strategies should not be viewed as an administrative or constraining control of their activity but, rather, as basic measures that are easy to implement at the bedside. A detailed knowledge of the epidemiology, based on adequate surveillance methodologies, is necessary to understand the pathophysiology and the rationale of preventive strategies that have been demonstrated to be effective. The principles of general preventive measures such as the implementation of standard and isolation precautions, and the control of antibiotic use are reviewed. Specific practical measures, targeted at the practical prevention and control of ventilator-associated pneumonia, sinusitis, and bloodstream, urinary tract, and surgical site infections are detailed. Recent data strongly confirm that these strategies may only be effective over prolonged periods if they can be integrated into the behavior of all staff members who are involved in patient care. Accordingly, infection control measures are to be viewed as a priority and have to be integrated fully into the continuous process of improvement of the quality of care.

Early goal-directed therapy in the treatment of severe sepsis and septic shock

BACKGROUND

Goal-directed therapy has been used for severe sepsis and septic shock in the intensive care unit. This approach involves adjustments of cardiac preload, afterload, and contractility to balance oxygen delivery with oxygen demand. The purpose of this study was to evaluate the efficacy of early goal-directed therapy before admission to the intensive care unit.

METHODS

We randomly assigned patients who arrived at an urban emergency department with severe sepsis or septic shock to receive either six hours of early goal-directed therapy or standard therapy (as a control) before admission to the intensive care unit. Clinicians who subsequently assumed the care of the patients were blinded to the treatment assignment. In-hospital mortality (the primary efficacy outcome), end points with respect to resuscitation, and Acute Physiology and Chronic Health Evaluation (APACHE II) scores were obtained serially for 72 hours and compared between the study groups.

RESULTS

Of the 263 enrolled patients, 130 were randomly assigned to early goal-directed therapy and 133 to standard therapy; there were no significant differences between the groups with respect to base-line characteristics. In-hospital mortality was 30.5 percent in the group assigned to early goal-directed therapy, as compared with 46.5 percent in the group assigned to standard therapy (P = 0.009). During the interval from 7 to 72 hours, the patients assigned to early goal-directed therapy had a significantly higher mean (+/-SD) central venous oxygen saturation (70.4+/-10.7 percent vs. 65.3+/-11.4 percent), a lower lactate concentration (3.0+/-4.4 vs. 3.9+/-4.4 mmol per liter), a lower base deficit (2.0+/-6.6 vs. 5.1+/-6.7 mmol per liter), and a higher pH (7.40+/-0.12 vs. 7.36+/-0.12) than the patients assigned to standard therapy (P < or = 0.02 for all comparisons). During the same period, mean APACHE II scores were significantly lower, indicating less severe organ dysfunction, in the patients assigned to early goal-directed therapy than in those assigned to standard therapy (13.0+/-6.3 vs. 15.9+/-6.4, P < 0.001).

CONCLUSIONS

Early goal-directed therapy provides significant benefits with respect to outcome in patients with severe sepsis and septic shock.

The microbiology of postoperative peritonitis

Postoperative peritonitis carries a higher risk of complications and mortality than does community-acquired disease. Little, however, is known about the specific microbiology of this condition. To gain insight into this problem, the microbiological findings of 67 patients with postoperative peritonitis were compared with those of 68 patients with community-acquired peritonitis. In a comparison of postoperative peritonitis with community-acquired disease, the number of isolates of enterococci (23 versus 6) and Enterobacter species (13 versus 4) were increased and the number of isolates of Escherichia coli (21 versus 42) were reduced. Antibiotic therapy before reintervention increased the number of resistant organisms at relaparotomy (33% versus 8%). The in vitro efficacy of the primary antibiotic or combination of drugs did not affect mortality rates (40% versus 38% after effective and ineffective treatment, respectively). Thus, the microbiology of postoperative peritonitis differs significantly from that of community-acquired disease, and specific antibiotic therapy is required, despite the doubtful impact on survival.

Using protocols to improve the outcomes of mechanically ventilated patients. Focus on weaning and sedation

The use of nonphysician-directed protocols and guidelines for the management of sedation and weaning has been shown to reduce the duration of mechanical ventilation for patients with acute respiratory failure when compared with conventional physician-directed practices. Practitioners in ICUs frequently are needed to perform multiple tasks and to evaluate numerous elements of clinical information in the care of the critically ill. In this complex environment, protocols and guidelines are one strategy for ensuring that specific tasks are carried out in a timely manner. Simple-to-employ methods for facilitating changes and improvements in the care of hospitalized patients recently have been proposed. These methods emphasize the importance of developing a culture of cooperation within the ICU so protocols and guidelines can be implemented successfully. Such a culture should embrace changes in medical practices in the ICU if they are associated with improved clinical outcomes. The results of studies evaluating the use of protocols and guidelines have important implications for general critical care practices, because many ICUs do not have physicians who are constantly at the patient's bedside. The need for effective communication from the bedside caregiver (e.g., nurse, respiratory therapist, pharmacist, technician) to the physician, so that treatment orders can be changed appropriately, usually results in some delay in the implementation of treatment changes. Protocols are one method for potentially reducing those delays and ensuring that medical care is administered in a more standardized and efficient manner.

Surveillance of antibiotic resistance in European ICUs

Antibiotic resistance among bacteria causing hospital-acquired infections poses a threat, particularly to patients in intensive care units (ICUs). In order to control the spread of resistant bacteria, local, regional and national resistance surveillance data must be used to develop efficient intervention strategies. In an attempt to identify national differences and the dynamics of antibiotic resistance in European ICUs, data have been merged from several networks of resistance surveillance performed during the 1990s. It should be stressed, however, that comparisons of results from different studies using different methods and different population samples must be made with caution. Antibiotic resistance across all species and drugs was, with some exceptions, highest in southern European countries and Russia, and lowest in Scandinavia. More effective strategies are needed to control the selection and spread of resistant organisms. Antibiotic intervention policies, efficient infection control measures and an overall awareness of the serious implications at public health level will contribute to the management of antibiotic resistance.

Experience with a clinical guideline for the treatment of ventilator-associated pneumonia

OBJECTIVE

To evaluate a clinical guideline for the treatment of ventilator-associated pneumonia.

DESIGN

Prospective before-and-after study design.

SETTING

A medical intensive care unit from a university-affiliated, urban teaching hospital.

PATIENTS

Between April 1999 and January 2000, 102 patients were prospectively evaluated.

INTERVENTIONS

Prospective patient surveillance, data collection, and implementation of an antimicrobial guideline for the treatment of ventilator-associated pneumonia.

MEASUREMENTS AND MAIN RESULTS

The main outcome evaluated was the initial administration of adequate antimicrobial treatment as determined by respiratory tract cultures. Secondary outcomes evaluated included the duration of antimicrobial treatment for ventilator-associated pneumonia, hospital mortality, intensive care unit and hospital lengths of stay, and the occurrence of a second episode of ventilator-associated pneumonia. Fifty consecutive patients with ventilator-associated pneumonia were evaluated in the before period and 52 consecutive patients with ventilator-associated pneumonia were evaluated in the after period. Severity of illness using Acute Physiology and Chronic Health Evaluation II (25.8 +/- 5.7 vs. 25.4 +/- 8.1, p =.798) and the clinical pulmonary infection scores (6.6 +/- 1.0 vs. 6.9 +/- 1.2, p =.105) were similar for patients during the two treatment periods. The initial administration of adequate antimicrobial treatment was statistically greater during the after period compared with the before period (94.2% vs. 48.0%, p <.001). The duration of antimicrobial treatment was statistically shorter during the after period compared with the before period (8.6 +/- 5.1 days vs. 14.8 +/- 8.1 days, p <.001). A second episode of ventilator-associated pneumonia occurred statistically less often among patients in the after period (7.7% vs. 24.0%, p =.030).

CONCLUSIONS

The application of a clinical guideline for the treatment of ventilator-associated pneumonia can increase the initial administration of adequate antimicrobial treatment and decrease the overall duration of antibiotic treatment. These findings suggest that similar types of guidelines employing local microbiological data can be used to improve overall antibiotic utilization for the treatment of ventilator-associated pneumonia.

Prospective randomized trials affect the outcomes of intraabdominal infection

OBJECTIVE

To compare the characteristics and outcomes of patients with intraabdominal infections enrolled in prospective randomized trials (PRTs) with those of a cohort of patients not enrolled in a trial.

SUMMARY BACKGROUND DATA

Prospective randomized trials are the gold standard for the evaluation of new treatments. Patients are screened using rigorous eligibility criteria and sometimes are excluded from PRTs because of associated medical conditions or more severe illness. However, the effect that the exclusion of these patients has on the applicability of clinical trial outcomes has not been defined.

METHODS

One hundred sixty-eight adults with intraabdominal infection were treated at a single institution during 7 years. Fifty-three patients were enrolled in four PRTs comparing various antibiotic regimens for treatment; 115 were not enrolled. Patient characteristics and outcomes of these two groups were compared.

RESULTS

Patients with infections from appendicitis (n = 68) had a low severity of illness and similar outcomes in both groups. These patients and those for whom a concurrent PRT was unavailable were excluded from subsequent analysis. Eighty-eight patients (42 PRT, 46 not enrolled) with serious infection remained for analysis. Patients enrolled in PRTs were younger, had less severe illness, had a decreased length of stay, a lower incidence of antibiotic resistance, and less frequent extraabdominal infections than those not enrolled in a trial. Patients enrolled in PRTs were more likely to be cured and were less likely to die. Logistic regression analysis demonstrated that cure was associated with a lower initial severity of illness, absence of antibiotic resistance, and participation in a PRT.

CONCLUSIONS

Patients with intraabdominal infection enrolled in PRTs have an increased likelihood of cure and survival. This is due in part to a lower incidence of antibiotic resistance, which may reflect improved drug selection. Patients not enrolled in PRTs are at greater risk for treatment failure and death because of concomitant illness. Outcomes from PRTs may not be applicable to all patients with intraabdominal infections.

Nosocomial Pneumonia: More Than Just Ventilator-Associated

We reviewed literature published from 1995 through 2000 on developments in ventilator-associated pneumonia. There is no gold standard with which to compare the accuracy of various invasive procedures performed for diagnosis. Moreover, leaders in the field are calling for an outcomes-based analysis to assess the utility of invasive procedures. Two things are clear: 1) adequate empiric therapy is beneficial, and 2) changes in therapy based on recovery of pathogens by invasive means do not affect outcome. Clinicians are urged to review local antimicrobial resistance patterns and to initiate empiric therapy on the basis of those data.

[Cefotaxime, twenty years later. Observational study in critically ill patients]

OBJECTIVE

Afer twenty years of commercial availability of cefotaxime, the objective of this study was to know the reasons and modes of use, administration dosage as well as its effectiveness and tolerance in critically ill patients admitted to Intensive Care Units (ICU) in our country.

DESIGN

Open, prospective, observational, multicenter study.

SUBJECTS

All patients who had cefotaxime administered in monotherapy or in combination with other antibiotics were included as cases in this study.

RESULTS

A total of 624 patients were included in 44 ICUs (average 14 cases). Cefotaxime was indicated for therapy of 274 community-acquired infections (43.9%), 194 prophylaxis (31.1%), and 156 nosocomial infections (25.0%). Both community-acquired pneumonia (149, 34.7%) and mechanical ventilation associated pneumonia (62, 14.4%) predominated, followed by trachebronchitis (60, 13.9%) and central nervous system infections (42, 9.8%). Over half of infections (222, 51.6%) presented as systemic inflammatory response syndrome (SIRS), 133 (30.9%) as severe sepsis, and 75 (17.4%) as septic shock. In 374 (87.0%) out of the 430 cases of infection treatment, cefotaxime wan prescribed on an empirical basis and in 150 of them (40.1%) a further confirmation of the causative agent was obtained. In 120 (27.9%) cases, cefotaxime was administered as monotherapy and in the remaining cases in association with one or more antibiotics.The use of cefotaxime as prophylaxis was evaluated as failure in 31 (16.0%) of the cases, whereas in treatment it was considered as failure in 98 (22.8%) of the 430 cases, 51 community-acquired infections, 27 (27.3%) of ICU-acquired infections, and 20 (35.1%) nosocomial infections acquired outside the ICU. In 127 (29.5%) of the 430 infection treatments the initial treatment was changed. The reasons for the change included clinical failure (36, 28.3%), recovery of an uncovered pathogen with the antibiotic (40, 31.5%), emergence of multi-resistant pathogens (28, 22.0%), to decrease the therapeutic spectrum (7, 5.5%), and other reasons (16). Cefotoxime was also changed in 21 (6.0%) of the 194 cases in which it was used as prophylaxis. In 32 (5.1%) patients 37 adverse effects were noted which were associated with a possible or likely use of cefotaxime. Most notably, diarrhoea in 15 (2.4%) occasions and skin rash in 6 cases (1.0%).

CONCLUSIONS

Cefotaxime is still one of the therapies of choice for community-acquired and nosocomial infections as well as in different prophylactic modes. It is mostly used on an empirical basis and associated with other antibiotics. Clinical and microbiological efficiency is high whereas adverse effects related to its use have been scarce.

Antimicrobial management measures to limit resistance: A process-based conceptual framework

To curb the trend toward increasingly resistant microorganisms, we must at least ensure that antibiotics are used in accordance with the best available scientific evidence. Here we review the control and streamlining measures aimed at optimizing the use of antibiotics, placing an emphasis on their demonstrated effectiveness in the intensive care unit environment. Because of their wide variety, the measures have been organized along the process of choosing, dosing, delivering, and then adjusting the initial antibiotics according to the culture results. By clarifying the range of options available, this process-based conceptual framework assists in best adapting a creative mixture of control measures to a particular healthcare system. The framework also facilitates the overview of a proposed multidisciplinary antibiotic management program, thereby helping to secure the administrative and local provider support necessary for its implementation and continued improvement.

Is there a role for antibiotic cycling in the intensive care unit?

Antibiotic resistance of bacterial pathogens has emerged as one of the most important issues facing critical care practitioners. Resistance of many commonly encountered bacterial species is increasing and has been associated with greater administration of inadequate antimicrobial therapy to patients within intensive care units. This has resulted in greater patient morbidity, higher mortality rates, and increased healthcare costs. Methods to reduce antimicrobial resistance have focused on increasing adherence to infection control practices and improving antibiotic utilization. Antibiotic cycling is a strategy to reduce antimicrobial resistance by withdrawing an antibiotic or antibiotic class from use and subsequently reintroducing it at a later point in time. The main goal of cycling is to allow resistance rates for specific antibiotics to decrease, or at least remain stable, when their use is periodically eliminated from the intensive care unit.

Using information systems technology to improve antibiotic prescribing

The selection of antimicrobial agents in the hospital setting is still a largely manual task and, therefore, fraught with the potential for error. This includes the choice of agents, dosage regimens, and monitoring for response and toxicity. The authors describe current and future strategies to use information technology to improve the process of antimicrobial selection and to avoid dosing errors and contraindicated drug combinations. The possible role of decision support in preventing the emergence of resistance is also discussed.

Impact of bloodstream infection on outcomes among infected surgical inpatients

OBJECTIVE

To assess the importance of bloodstream infection (BSI) to outcomes among infected surgical patients.

BACKGROUND

Bloodstream infection complicating infection is thought to connote a more serious condition compared with a primary infection alone. The authors recently reported, however, that BSI does not alter outcomes with central venous catheter colonization in the presence of sepsis. The significance of BSI with other infections has been incompletely evaluated.

METHODS

Data on all episodes of infection among surgical patients were collected prospectively during a 38-month period at a single hospital, then analyzed retrospectively to determine the independent prognostic value of BSI for all infections by logistic regression analysis, and for abdominal infections and pneumonia using matched control groups.

RESULTS

During the study period, 2,076 episodes of infection occurred, including 363 with BSI. Patients with BSI had a greater severity of illness and a greater death rate. After logistic regression, however, BSI did not independently predict death. After matching patients with abdominal infections and pneumonia with BSI to patients without BSI but with a similar site of infection, severity of illness, age, and causative organism, no difference in outcome was seen.

CONCLUSIONS

Bloodstream infection is associated with critical illness and death but appears to be a marker of severe primary disease rather than an independent predictor of outcome.

Respiratory infection in the chronically critically ill patient. Ventilator-associated pneumonia and tracheobronchitis

The long-term ventilated patient is at high risk for developing nosocomial pneumonia or tracheobronchitis. In general, the frequency of infection increases with the duration of mechanical ventilation, but the risk appears to be greatest in the first week of intubation. Although these types of infection are common and may have morbidity and mortality impact, the daily risk is less in the long-term ventilated patient than in the acutely ill intubated patient. This reduced daily risk may reflect a "survivor effect," with less healthy patients dying early in the hospital stay and not surviving long enough to undergo tracheostomy and long-term ventilation. A number of factors predispose these patients to infection, including host defense impairment and exposure to large numbers of bacteria. This exposure can occur through the airway, and proper care of respiratory therapy devices is essential to minimize the risk for infection. Most infections of the lower respiratory tract are preceded by airway colonization with EGN bacteria and, with improvement in host defenses and nutrition, infection in the face of colonization is less likely. In some patients, colonization can be eliminated. When the long-term ventilated patient does develop infection, it generally involves highly resistant gram-negative or gram-positive organisms and therapy should be prompt and appropriate. Not all such patients respond to systemic antibiotics, and the use of adjunctive aerosol therapy may have benefit for those with either tracheobronchitis or pneumonia, especially if highly resistant pathogens are present.

An open, randomised, multi-centre study comparing the safety and efficacy of sitafloxacin and imipenem/cilastatin in the intravenous treatment of hospitalised patients with pneumonia

This was a phase II, randomised, open-label, multi-centre study to assess the safety, tolerability, and efficacy of sitafloxacin (DU-6859a, 400 mg once daily) compared with imipenem (imipenem/cilastatin, 500 mg three times daily) in the treatment of hospitalised patients with pneumonia. Patients (n=69) were entered into the study in the intent-to-treat group, 35 in the sitafloxacin and 34 in the imipenem group. Patients (n=65) were included in the clinically evaluable population and 42 in the bacteriologically evaluable population. Baseline demographic data and clinical characteristics were similar for both treatment groups and across all patient populations. The incidence, severity and type of adverse events were similar in both treatment groups. The frequency of adverse events, which were considered to be related to the study of drugs was low and generally similar between the two groups. Mild transient increases in alanine aminotransferase and alkaline phosphatase occurred in the sitafloxacin treatment group, but there were no apparent trends in the other serum enzyme levels. The clinical response at the first and second follow-up assessments indicated that 94-97% of patients in the clinically evaluable population and 91% of patients in the intent-to-treat population were classified as cured in both treatment groups. The bacteriological response was classified as satisfactory for all patients (100%) in the bacteriologically evaluable population in the imipenem treatment group and satisfactory for 90 and 95% of cases at the first and second follow-up assessments in the bacteriologically evaluable population in the sitafloxacin treatment group, respectively. In conclusion, for the treatment of pneumonia, sitafloxacin was considered as safe and as tolerable as imipenem and preliminary data from this study suggest that it may have similar efficacy.

The Year in Review: Critical Care Medicine

Background: There have been significant recent advances in the pharmacotherapeutic management of critically ill patients. The purpose of this article is to review and discuss the most pertinent published literature in the areas of neurology, cardiovascular diseases, infectious diseases, nephrology, hematology, and gastroenterology as it pertains to critical care in order to provide an update for the critical care practitioner.

Methods: We performed a Medline search from July 1999 to December 2000 utilizing terms relating to the pharmacotherapy of the specific aforementioned topics in critical care medicine. We focused on English-language clinical studies performed in adult intensive care unit (ICU) patients. From these articles we selected those that would have a practical impact on drug therapy in the ICU or the development of drug usage guidelines for critically ill patients. Review articles were generally not included.

Results: The following topics were found to be either new developments or of potentially significant impact in the management of adult critically ill patients. In the area of neurology, advances were found with respect to optimization of regimens for sedative and neuromuscular blocking agents, validation of sedation scales and tools, and in the treatment of head injury patients. In the cardiovascular diseases, most studies related to the hemodynamic support of septic shock. We focus on developments in fluid resuscitation, optimization of global and regional oxygen transport variables, the repositioning of vasopressor agents, and a return to the use of steroids. Given the high mortality rate associated with the development of acute renal failure in the ICU, there has been a consistent attempt to develop preventative and treatment strategies for these patients, including optimization of antimicrobial dosing methods. Several epidemiological and longitudinal studies document changes in multi-drug antimicrobial resistance patterns. The use of treatment guidelines for antimicrobials in the critically ill improves outcomes in most patients. Significant attention has focused on the characterization of anemia in the ICU and the development of alternative pharmacological strategies in its treatment. Finally, in gastroenterology, the main focus has been the investigation of methods to optimize the delivery of enteral nutrition given its proven benefits in critically ill patients.

Conclusions: Significant advances in the areas of neurological, cardiovascular, infectious diseases, renal, hematological, and gastrointestinal issues in the pharmacotherapy of critically ill patients have been published over the course of the past year. Many of these studies have yielded data that may be incorporated into the pharmacotherapeutic management of ICU patients, hence maximizing outcomes.

Efficacy of meropenem as monotherapy in the treatment of ventilator-associated pneumonia

We performed a prospective, open label, randomized study in intensive care unit patients with ventilator-associated pneumonia (VAP) to determine the efficacy and safety of empiric intravenous (i.v.) meropenem monotherapy compared with the combination of ceftazidime plus amikacin. A total of 140 patients receiving mechanical ventilation and diagnosed with pneumonia were included in the study. Patients were randomized to receive either 1 g meropenem i.v. every 8 hours or 2 g ceftazidime i.v. every 8 hours plus 15 mg/kg amikacin daily, administered to patients with normal renal function as two daily doses. Satisfactory clinical responses (cure or improvement) were achieved at the end of treatment in 68.1% of meropenem-treated patients and 54.9% in the ceftazidime/amikacin-treated group (relative risk 1.25; 95% confidence interval >1.00, 1.55). When non-evaluable patients were excluded from the analysis, the satisfactory clinical response was 82.5% and 66.1% for the meropenem and ceftazidime/amikacin patients, respectively (p = 0.044). Logistic regression demonstrated that treatment with meropenem and both the basic traumatic and medical pathologies were significantly associated with a satisfactory response. Adverse events judged to be possibly or probably related to treatment were reported by seven (10.1%) patients in the meropenem group and by eight patients (11.3%) in the ceftazidime/amikacin group. The results of this study confirm that monotherapy with meropenem is well tolerated and provides superior efficacy to the conventional combination of ceftazidime and amikacin in combating VAP.

Hospital-acquired pneumonia: risk factors, microbiology, and treatment

Pneumonia complicates hospitalization in 0.5 to 2.0% of patients and is associated with considerable morbidity and mortality. Risk factors for hospital-acquired pneumonia (HAP) include mechanical ventilation for > 48 h, residence in an ICU, duration of ICU or hospital stay, severity of underlying illness, and presence of comorbidities. Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter are the most common causes of HAP. Nearly half of HAP cases are polymicrobial. In patients receiving mechanical ventilation, P aeruginosa, Acinetobacter, methicillin-resistant S aureus, and other antibiotic-resistant bacteria assume increasing importance. Optimal therapy for HAP should take into account severity of illness, demographics, specific pathogens involved, and risk factors for antimicrobial resistance. When P aeruginosa is implicated, monotherapy, even with broad-spectrum antibiotics, is associated with rapid evolution of resistance and a high rate of clinical failures. For pseudomonal HAP, we advise combination therapy with an antipseudomonal beta-lactam plus an aminoglycoside or a fluoroquinolone (eg, ciprofloxacin).

Linezolid (PNU-100766) versus vancomycin in the treatment of hospitalized patients with nosocomial pneumonia: a randomized, double-blind, multicenter study

Linezolid, the first oxazolidinone, is active against gram-positive bacteria, including multidrug-resistant strains. This multinational, randomized, double-blind, controlled trial compared the efficacy, safety, and tolerability of linezolid with vancomycin in the treatment of nosocomial pneumonia. A total of 203 patients received intravenous linezolid, 600 mg twice daily, plus aztreonam, and 193 patients received vancomycin, 1 g intravenously twice daily, plus aztreonam for 7-21 days. Clinical and microbiological outcomes were evaluated at test of cure 12-28 days after treatment. Clinical cure rates (71 [66.4%] of 107 for linezolid vs. 62 [68.1%] of 91 for vancomycin) and microbiological success rates (36 [67.9%] of 53 vs. 28 [71.8%] of 39, respectively) for evaluable patients were equivalent between treatment groups. Eradication rates of methicillin-resistant Staphylococcus aureus and safety evaluations were similar between treatment groups. Resistance to either treatment was not detected. Linezolid is a well-tolerated, effective treatment for adults with gram-positive nosocomial pneumonia.

Optimizing antibiotic therapy in the intensive care unit setting

Antibiotics are one of the most common therapies administered in the intensive care unit setting. In addition to treating infections, antibiotic use contributes to the emergence of resistance among pathogenic microorganisms. Therefore, avoiding unnecessary antibiotic use and optimizing the administration of antimicrobial agents will help to improve patient outcomes while minimizing further pressures for resistance. This review will present several strategies aimed at achieving optimal use of antimicrobial agents. It is important to note that each intensive care unit should have a program in place which monitors antibiotic utilization and its effectiveness. Only in this way can the impact of interventions aimed at improving antibiotic use (e.g. antibiotic rotation, de-escalation therapy) be evaluated at the local level.

Antibacterial treatment of invasive mechanical ventilation-associated pneumonia

Patients admitted to intensive care units (ICU) are at higher risk of acquiring nosocomial infections than patients in other hospital areas. This is the consequence of both a greater severity of illness with its implications (manipulation, invasiveness) and crossed infection from reservoirs inside the ICU. The most frequent nosocomial infection is invasive ventilation-associated pneumonia (VAP) which leads to an important increase in morbidity and mortality. The most important aetiological agents in VAP are bacteria, with a marked predominance of Staphylococcus aureus and Pseudomonas aeruginosa. These aetiologies may be different depending upon the type of ICU (medical, surgical, coronary) or the presence of certain risk factors (duration of mechanical ventilation before onset of pneumonia, previous exposure to antibacterials). Susceptibilities of the aetiological agents to antibacterials may also vary according to the type of ICU and over time. Data from global studies show an increase in multiresistant bacteria but these data may not be applied to a local ICU. The availability of accurate and updated information on the most frequently encountered organisms in each ICU and their susceptibilities is very important in order to provide the most adequate treatment. A controversial issue is the selection of antibacterials. According to the latest evidence the most adequate approach is a prompt administration of empirical treatment. Based on knowledge of bacterial flora in our own ICU, the choice of an adequate therapeutic regimen will decrease both morbidity and mortality. A second issue is monotherapy versus combined therapy. The most common recommendation, with a few exceptions, is to use combined therapy until microbiological results are received. Another controversy is the choice of antibacterials in the combined regimen. The most commonly recommended combination is that of a beta-lactam with an aminoglycoside, except in early-onset pneumonia without risk factors. The use of monotherapy with a cefalosporin without antipseudomonal activity or amoxicillin-clavulanic acid is the recommended regimen. Treatment should be modified based on microbiological results. There are no well documented recommendations on the prophylactic duration of treatment and it must be based on the aetiological agent and the clinical course. In summary treatment of VAP must be prompt, empirical and combined (beta-lactam plus aminoglycoside ). However, the choice of the antibacterial regimen should follow local guidelines of treatment based upon the knowledge of the most frequently isolated bacterial flora and their susceptibilities in different clinical settings.

Management of antimicrobial use in the intensive care unit

Indications for the use of antimicrobials in critically ill patients are similar to those for other hospitalised patients. However, the selection of agents depends on the particular characteristics of patients in the intensive care unit (ICU), the form of presentation of infection, the type of infection and the bacteriological features of the causative pathogens. The use of antimicrobials in patients admitted to medical-surgical ICUs varies between 33 and 53%. The selection of empirical antimicrobials to be included in treatment protocols of the most common infections depends on the strong interrelationship between patient characteristics, predominant pathogens in each focus. and antimicrobials used for treatment. Epidemiological studies carried out in the past have identified the microorganisms most frequently responsible for community-acquired and nosocomial infections in patients admitted to ICUs. Susceptibility to antimicrobial agents may be different between each geographical area, between each hospital and even within the same hospital service. In addition, susceptibility patterns may change temporarily in relation to the use of particular antimicrobials or in association with other unknown factors so that assessment of endemic antimicrobial resistance patterns is very useful in order to tailor the antimicrobial regimens of therapeutic protocols. Antimicrobial use should not be a routine procedure. The clinical course of the patient (an indicator of effectiveness) should be closely monitored as well as the possible appearance of adverse effects and/or multiresistant pathogens. Controls are based on the assessment of plasma drug concentrations and microbiological surveillance to detect the presence of multiresistant strains or new antibacterial-resistant pathogens. Prevention of the development of multiresistant pathogens is the main goal of the ICU antimicrobial policy. Although a series of general strategies to reduce the presence of multiresistant pathogens have been proposed, the implementation of these recommendations in ICUs requires the cooperation of a member of the intensive care team.

Inadequate treatment of nosocomial infections is associated with certain empiric antibiotic choices

OBJECTIVE

The purpose of this study was to determine the impact of scheduled changes of antibiotic classes, used for the empirical treatment of suspected or documented Gram-negative bacterial infections, on the occurrence of inadequate antimicrobial treatment of nosocomial infections.

DESIGN

Prospective observational study.

SETTING

Medical (19-bed) and surgical (18-bed) intensive care units in an urban teaching hospital.

PATIENTS

A total of 3,668 patients requiring intensive care unit admission were prospectively evaluated during three consecutive time periods.

INTERVENTIONS

During each time period, one antibiotic class was selected for the empirical treatment of Gram-negative bacterial infections as follows: time period 1 (baseline period) (1,323 patients), ceftazidime; time period 2 (1,243 patients), ciprofloxacin; and time period 3 (1,102 patients), cefepime.

MEASUREMENTS AND MAIN RESULTS

The overall administration of inadequate antimicrobial treatment for nosocomial infections decreased during the course of the study (6.1%, 4.7%, and 4.5%; p = .15). This was primarily because of a statistically significant decrease in the administration of inadequate antibiotic treatment for Gram-negative bacterial infections (4.4%, 2.1%, and 1.6%; p < .001). There were no statistically significant differences in the overall hospital mortality rate among the three time periods (15.6%, 16.4%, and 16.2%; p = .828) despite a significant increase in severity of illness as measured with Acute Physiology and Chronic Health Evaluation (APACHE) II scores (15.3 +/- 7.6, 15.7 +/- 8.0, and 20.7 +/- 8.6; p < .001). The hospital mortality rate decreased significantly during time period 3 (20.6%) compared with time period 1 (28.4%; p < .001) and time period 2 (29.5%; p < .001) for patients with an APACHE II score > or = 15.

CONCLUSIONS

These data suggest that scheduled changes of antibiotic classes for the empirical treatment of Gram-negative bacterial infections can reduce the occurrence of inadequate antibiotic treatment for nosocomial infections. Reducing inadequate antibiotic administration may improve the outcomes of critically ill patients with APACHE II scores > or = 15.

Inadequate antimicrobial treatment: an important determinant of outcome for hospitalized patients

Inadequate antimicrobial treatment, generally defined as microbiological documentation of an infection that is not being effectively treated, is an important factor in the emergence of infections due to antibiotic-resistant bacteria. Factors that contribute to inadequate antimicrobial treatment of hospitalized patients include prior antibiotic exposure, use of broad-spectrum antibiotics, prolonged length of stay, prolonged mechanical ventilation, and presence of invasive devices. Strategies to minimize inadequate treatment include consulting an infectious disease specialist, using antibiotic practice guidelines, and identifying quicker methods of microbiological identification. In addition, clinicians should determine the prevailing pathogens that account for the community-acquired and nosocomial infections identified in their hospitals. Clinicians can improve antimicrobial treatment by using empirical combination antibiotic therapy based on individual patient characteristics and the predominant bacterial flora and their antibiotic susceptibility profiles. This broad-spectrum therapy can then be narrowed when initial culture results are received. Further study evaluating the use of antibiotic practice guidelines and strategies to reduce inadequate treatment is necessary to determine their impact on patient outcomes.