Duration of Hospital Admission and the Need for Empirical Antipseudomonal Therapy

Abstract

fTo reduce selective pressure for antimicrobial resistance, empirical use of antipseudomonal antibiotics is often reserved for patients with late-onset hospital-acquired infections. We examined the likelihood of isolating Pseudomonas aeruginosa as a function of time from hospital admission. We conducted a retrospective cohort study of all positive bacterial cultures in a tertiarycare hospital between March 2010 and November 2011. The primary outcome was the proportion of positive cultures yielding P. aeruginosa. Multivariable logistic regression was employed to assess the impact of time from admission on the likelihood of isolating P. aeruginosa, after adjusting for other important risk factors. A total of 7,668 positive cultures were obtained from 4,108 unique patients during the study interval, including 633 (8.3%) yielding P. aeruginosa. The probability of isolating P. aeruginosa increased linearly from 79/2,044 (3.9%) positive cultures obtained on admission to 153/664 (23%) in the 10th week of admission or beyond. The unadjusted odds ratio was 1.002/day (95% confidence interval [CI], 1.0016 to 1.0028; P < 0.0001); the adjusted odds ratio (aOR) was 1.0007/day (95% CI, 1.0001 to 1.0013; P ‫؍‬ 0.02). Other important predictors of P. aeruginosa isolation included respiratory specimen type (aOR, 13.8; 95% CI, 9.1 to 21.1), recent hospital admission (aOR,1.8; 95% CI, 1.4 to 2.3), prior P. aeruginosa isolation during current admission (aOR, 4.9; 95% CI, 3.7 to 6.4), and prior antipseudomonal (aOR, 1.9; 95% CI, 1.4 to 2.5) or nonantipseudomonal (aOR, 1.8; 95% CI, 1.4 to 2.4) antibiotic exposure. It was determined that as time from admission increases, there is a linear increase in the likelihood of P. aeruginosa isolation. Any guidelines which distinguish early from late hospital-acquired infection must consider the implications of time point selection on the likelihood of inadequate P. aeruginosa empirical coverage. P seudomonas aeruginosa is a prototypic nosocomial pathogen. It is among the most common causes of hospital-acquired infections (17), while it is infrequently responsible for communityacquired disease (20). P. aeruginosa is also a prototypic resistant pathogen, intrinsically resistant to most antibacterial agents and able to acquire almost all known mechanisms of antibacterial resistance (21). Very few available antibacterial agents offer reliable antipseudomonal activity. Therefore, as a general principle, use of these drugs is spared, if possible, to avoid driving further increases in resistance. However, minimization of empirical antimicrobials is challenging, because the adequacy of early antibiotic therapy (before microbiological results are available) is strongly associated with patient survival in critically ill patients (8,11,12). The stakes of failing to adequately cover P. aeruginosa during the empirical window may be particularly high (10), since this organism possesses a vast array of virulence factors (23) and is associated with higher clinical failure, relapse, and mortality rates than mos...

Contributors to the length-of-stay trajectory in burn-injured patients

“…In patients with >40%TBSA, approximately 75% of all deaths are known to be related to sepsis [21], and often is followed by multiple organ dysfunction [22]. Further complicating matters is the fact that antibiotic resistance is directly proportional to LOS [23], with the gram-negative Pseudomonas aeruginosa being the predominant pathogen in increased LOS [23, 24]. Multidrug resistant bacteria are now the leading cause of deaths due to sepsis [25].…”

Sending repeat cultures: is there a role in the management of bacteremic episodes? (SCRIBE study)

“…Patients with episodes of bacteremia were identified using the Stewardship Program Integrated Resource Information Technology (SPIRIT) database at SHSC. The database, as previously described [ 13 , 14 ], is automatically populated by health level 7 (HL7) messages from pharmacy, microbiology and electronic patient care databases for all admitted and previously admitted patients. For the patients included in the nested case control analysis, a focused review of the patients’ charts was conducted to extract more detailed clinical data regarding the source of infection and the patients’ clinical status at the time of repeat blood culture collection.…”

Antibacterial activity of five Peruvian medicinal plants against Pseudomonas aeruginosa

“…This term represents their escape from the effects of the antibacterial agents or the nonexistence of newer and more effective antibiotics [2]. P. aeruginosa is the most important toxigenic pathogen within the genus Pseudomonas because of the quantity and types of invasive infections it produces, as well as the noteworthy morbidity and mortality associated [3] . This Gram-negative bacterium has the ability to survive in adverse environments and develop multiple antibiotic resistance mechanisms.…”