Novel Antibiotics for Gram-Negative Nosocomial Pneumonia

Nosocomial pneumonia, including hospital-acquired pneumonia and ventilator-associated pneumonia, is the leading cause of death related to hospital-acquired infections among critically ill patients. A growing proportion of these cases are attributed to multi-drug-resistant (MDR-) Gram-negative bacteria (GNB). MDR-GNB pneumonia often leads to delayed appropriate treatment, prolonged hospital stays, and increased morbidity and mortality. This issue is compounded by the increased toxicity profiles of the conventional antibiotics required to treat MDR-GNB infections. In recent years, several novel antibiotics have been licensed for the treatment of GNB nosocomial pneumonia. These novel antibiotics are promising therapeutic options for treatment of nosocomial pneumonia by MDR pathogens with certain mechanisms of resistance. Still, antibiotic resistance remains an evolving global crisis, and resistance to novel antibiotics has started emerging, making their judicious use crucial to prolong their shelf-life. This article presents an up-to-date review of these novel antibiotics and their current role in the antimicrobial armamentarium. We critically present data for the pharmacokinetics/pharmacodynamics, the in vitro spectrum of antimicrobial activity and resistance, and in vivo data for their clinical and microbiological efficacy in trials. Where possible, available data are summarized specifically in patients with nosocomial pneumonia, as this cohort may exhibit 'critical illness' physiology that affects drug efficacy.

Nosocomial sepsis and drug susceptibility pattern among patients admitted to adult intensive care unit of Ayder Comprehensive Specialized Hospital, Northern Ethiopia

OBJECTIVE

Developing nosocomial sepsis within intensive care unit (ICU) is associated with increased mortality, morbidity, and length of hospital stay. But information is scarce regarding nosocomial sepsis in intensive care units of Northern Ethiopia. Hence, this study aims to determine the incidence of nosocomial sepsis, associated factors, bacteriological profile, drug susceptibility pattern, and outcome among patients admitted to the adult ICU of Ayder Comprehensive Specialized Hospital (ACSH), which is the largest tertiary hospital in Northern Ethiopia.

METHOD

Facility-based longitudinal study was conducted by following 278 patients who were admitted for more than 48 h to adult ICU of ACSH, from October 2016 to October 2017. Data were collected from charts, electronic medical records, and microbiology registration book using a checklist. The collected data were subjected to descriptive statistics and multivariable logistic regression using SPSS version 25. Statistical significance was declared at p < 0.05.

RESULT

Of all the patients, 60 (21.6%) of them acquired nosocomial sepsis. The risk of mortality was about two times higher among adult ICU patients who acquired nosocomial sepsis (RR = 2.2; 95% CI of RR = 1.3-3.5; p = 0.003). The odds of acquiring nosocomial sepsis among those who were on a mechanical ventilator (MV) and stayed more than a week were 5.7 and 9.3 times higher, respectively, than their corresponding counterparts. Among 48 isolates, Klebsiella was the most common pathogen. The isolates had a broad antibiotic resistance pattern for cephalosporins, penicillins, and methicillin.

CONCLUSION

The incidence of nosocomial sepsis in the adult ICU patients of ACSH was higher when compared to the incidence reported from some African and Asian countries. Mortality was higher among patients who acquired nosocomial sepsis. Use of MV and longer length of ICU stay were the significant predictors of nosocomial sepsis. The isolates were resistant to several antibiotics. Therefore, strict application of infection prevention strategies and appropriate use of antibiotics is so crucial. As well, priority should be given to patients who develop nosocomial sepsis in ICU.

Validating a prediction tool to determine the risk of nosocomial multidrug-resistant Gram-negative bacilli infection in critically ill patients: A retrospective case-control study

BACKGROUND

The Singapore GSDCS score was developed to enable clinicians predict the risk of nosocomial multidrug-resistant Gram-negative bacilli (RGNB) infection in critically ill patients. We aimed to validate this score in a UK setting.

METHOD

A retrospective case-control study was conducted including patients who stayed for more than 24h in intensive care units (ICUs) across two tertiary National Health Service hospitals in London, UK (April 2011-April 2016). Cases with RGNB and controls with sensitive Gram-negative bacilli (SGNB) infection were identified.

RESULTS

The derived GSDCS score was calculated from when there was a step change in antimicrobial therapy in response to clinical suspicion of infection as follows: prior Gram-negative organism, Surgery, Dialysis with end-stage renal disease, prior Carbapenem use and intensive care Stay of more than 5 days. A total of 110 patients with RGNB infection (cases) were matched 1:1 to 110 geotemporally chosen patients with SGNB infection (controls). The discriminatory ability of the prediction tool by receiver operating characteristic curve analysis in our validation cohort was 0.75 (95% confidence interval 0.65-0.81), which is comparable with the area under the curve of the derivation cohort (0.77). The GSDCS score differentiated between low- (0-1.3), medium- (1.4-2.3) and high-risk (2.4-4.3) patients for RGNB infection (P<0.001) in a UK setting.

CONCLUSION

A simple bedside clinical prediction tool may be used to identify and differentiate patients at low, medium and high risk of RGNB infection prior to initiation of prompt empirical antimicrobial therapy in the intensive care setting.

Reliable Identification of Benign Clinical Course in Aneurysmal Subarachnoid Hemorrhage: A Simple and Qualitative Algorithm

BACKGROUND

A reliable method to specifically identify low vasospasm risk in aneurysmal subarachnoid hemorrhage (aSAH) patients has not been previously proposed.

OBJECTIVE

To develop a clinical algorithm using admission aSAH clinical severity and subarachnoid blood distribution to identify patients at low risk of clinical vasospasm.

METHODS

Clinical severities, admission noncontrasted head computerized tomography (CT) scan, and incidences of vasospasm among 291 aSAH patients treated at our institution were evaluated. Admission head CTs were assessed for distributions of cisternal and ventricular blood. Patients with the following 4 criteria experienced considerably lower risk of vasospasm: (1) Hunt Hess grade 1 to 2, (2) Lack of thick subarachnoid blood filling 2 adjacent cisterns, (3) Lack of thick interhemispheric blood, and (4) Lack of biventricular intraventricular hemorrhage.

RESULTS

One hundred thirty-three patients (45.7%) developed cerebral vasospasm. Hunt Hess grade greater than 2 (odds ratio [OR] 4.52, 95% confidence interval [CI] 2.74-7.46), adjacent cistern blood (OR 4.1, 95% CI 2.51-6.7), interhemispheric thick blood (OR 5.72, 95% CI 3.41-9.59), and biventricular intraventricular hemorrhage (OR 1.92, 95% CI 1.19-3.02) were significant risk factors. Application of our algorithm yielded a sensitivity of 29%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 54.5%, which was superior compared to metrics from current institutional practice criteria. Inter-rater agreement was substantial at mean kappa = 0.75.

CONCLUSION

Application of our novel clinical algorithm produced successful identification of aSAH patients who experience zero risk of clinical vasospasm. Our algorithm is simple to apply with high reliability and is superior to currently available clinical and radiographic metrics.

Vasospasm Risk in Surgical ICU Patients With Grade I Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is associated with high mortality. The initial hemorrhage causes death in approximately 25% of patients, with most subsequent mortality being attributable to delayed cerebral ischemia (DCI). Delayed cerebral ischemia generally occurs on post-bleed days 4 through 20, with the incidence peaking at day 8. Because of the risks of DCI, patients with SAH are usually monitored in an intensive care unit (ICU) for 14 to 21 days. Unfortunately, prolonged ICU admissions are expensive and are associated with well-documented risks to patients. We hypothesized that a subset of patients who are at low risk of DCI should be safe to transfer out of the ICU early. All patients admitted to Montefiore Medical Center from 2008 to 2013 with grade I SAH who had their aneurysms successfully protected, had an uncomplicated postoperative course, and had no clinical or ultrasonographic evidence of DCI after day 8 were retrospectively studied. The primary outcome was clinical or ultrasonographic evidence of the development of DCI after day 8. Secondary outcomes included length of ICU and hospital stay and hospital mortality. Forty patients who met the above-mentioned criteria were identified. Of these, only 1 (2.5%) developed ultrasonographic evidence of DCI after day 8 but required no intervention. The mean length of stay in the ICU was until post-bleed day 13, and the mean hospital length of stay was until post-bleed day 14. The in-hospital mortality was 0 of 40. Thus, we identified a low-risk subset of patients with grade I SAH who may be candidates for early transfer out of the ICU.

A prediction tool for nosocomial multi-drug Resistant Gram-Negative Bacilli infections in critically ill patients - prospective observational study

Background

The widespread use of empiric broad spectrum antibiotics has contributed to the global increase of Resistant Gram-Negative Bacilli (RGNB) infections in intensive care units (ICU). The aim of this study was to develop a tool to predict nosocomial RGNB infections among ICU patients for targeted therapy.

Methods

We conducted a prospective observational study from August'07 to December'11. All adult patients who were admitted and stayed for more than 24 hours at the medical and surgical ICU's were included. All patients who developed nosocomial RGNB infections 48 hours after ICU admission were identified. A prediction score was formulated by using independent risk factors obtained from logistic regression analysis. This was prospectively validated with a subsequent cohort of patients admitted to the ICUs during the following time period of January-September 2012.

Results

Seventy-six patients with nosocomial RGNB Infection (31bacteremia) were compared with 1398 patients with Systemic Inflammatory Response Syndrome (SIRS) without any gram negative bacterial infection/colonization admitted to the ICUs during the study period. The following independent risk factors were obtained by a multivariable logistic regression analysis - prior isolation of Gram negative organism (coeff: 1.1, 95% CI 0.5-1.7); Surgery during current admission (coeff: 0.69, 95% CI 0.2-1.2); prior Dialysis with end stage renal disease (coeff: 0.7, 95% CI 0.1-1.1); prior use of Carbapenems (coeff: 1.3, 95% CI 0.3-2.3) and Stay in the ICU for more than 5 days (coeff: 2.4, 95% CI 1.6-3.2). It was validated prospectively in a subsequent cohort (n = 408) and the area-under-the-curve (AUC) of the GSDCS score for predicting nosocomial ICU acquired RGNB infection and bacteremia was 0.77 (95% CI 0.68-0.89 and 0.78 (95% CI 0.69-0.89) respectively. The GSDCS (0-4.3) score clearly differentiated the low (0-1.3), medium (1.4-2.3) and high (2.4-4.3) risk patients, both for RGNB infection (p:0.003) and bacteremia (p:0.009).

Conclusion

GSDCS is a simple bedside clinical score which predicts RGNB infection and bacteremia with high predictive value and differentiates low versus high risk patients. This score will help clinicians to choose appropriate, timely targeted antibiotic therapy and avoid exposure to unnecessary treatment for patients at low risk of nosocomial RGNB infection. This will reduce the selection pressure and help to contain antibiotic resistance in ICUs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0615-z) contains supplementary material, which is available to authorized users.