Ventilator-Associated Pneumonia at a Tertiary-Care Center in a Developing Country: Incidence, Microbiology, and Susceptibility Patterns of Isolated Microorganisms

Rebound Inverts the Staphylococcus aureus Bacteremia Prevention Effect of Antibiotic Based Decontamination Interventions in ICU Cohorts with Prolonged Length of Stay

Could rebound explain the paradoxical lack of prevention effect against Staphylococcus aureus blood stream infections (BSIs) with antibiotic-based decontamination intervention (BDI) methods among studies of ICU patients within the literature? Two meta-regression models were applied, each versus the group mean length of stay (LOS). Firstly, the prevention effects against S. aureus BSI [and S. aureus VAP] among 136 studies of antibiotic-BDI versus other interventions were analyzed. Secondly, the S. aureus BSI [and S. aureus VAP] incidence in 268 control and intervention cohorts from studies of antibiotic-BDI versus that among 165 observational cohorts as a benchmark was modelled. In model one, the meta-regression line versus group mean LOS crossed the null, with the antibiotic-BDI prevention effect against S. aureus BSI at mean LOS day 7 (OR 0.45; 0.30 to 0.68) inverted at mean LOS day 20 (OR 1.7; 1.1 to 2.6). In model two, the meta-regression line versus group mean LOS crossed the benchmark line, and the predicted S. aureus BSI incidence for antibiotic-BDI groups was 0.47; 0.09-0.84 percentage points below versus 3.0; 0.12-5.9 above the benchmark in studies with 7 versus 20 days mean LOS, respectively. Rebound within the intervention groups attenuated and inverted the prevention effect of antibiotic-BDI against S. aureus VAP and BSI, respectively. This explains the paradoxical findings.

The Emergence and Dissemination of Multidrug Resistant Pseudomonas aeruginosa in Lebanon: Current Status and Challenges during the Economic Crisis

Pseudomonas aeruginosa is a common cause of healthcare-associated infections and chronic airway diseases in non-clinical settings. P. aeruginosa is intrinsically resistant to a variety of antimicrobials and has the ability to acquire resistance to others, causing increasingly recalcitrant infections and elevating public health concerns. We reviewed the literature on multidrug-resistant (MDR) P. aeruginosa isolated from humans (nosocomial and community-associated), animals, and the environment in Lebanon, a country that has been suffering from a surge in antimicrobial resistance (AMR). We identified 24 studies that described the epidemiology and antimicrobial susceptibility profiles of P. aeruginosa. Our analysis showed that the bacterium was predominant in lesions of patients on mechanical ventilation and in burn patients and those with diabetic foot infections and hematological malignancies. We also found that carbapenem resistance in P. aeruginosa isolates in Lebanon involved both enzymatic and non-enzymatic mechanisms but depended predominantly on VIM-2 production (40.7%). Additionally, MDR P. aeruginosa was detected in animals, where a recent study reported the emergence of carbapenemase-producing P. aeruginosa in livestock in Lebanon. Notably, no studies evaluated the contribution of MDR P. aeruginosa in the environment to human infections. Taken together, our findings highlight the need for AMR surveillance programs and a national action plan to combat resistance in Lebanon.

Microbial etiologies of ventilator-associated pneumonia (VAP) in intensive care unit of Beni-Suef University's Hospital

Background

Ventilator-associated pneumonia (VAP) is a major health problem for people intubated in intensive care units (ICUs), leading to increased mortality rates, hospital stay, and treatment costs. In the present study, the core pathogens causing VAP in Beni-Suef University's Hospital, Egypt, was investigated over a study period of 2 years (2017–2019).

Results

Of a total of 213 patients subjected to mechanical ventilation, 60 have developed VAP during their stay in the ICU. The mortality rate reached 41.7% among VAP patients. Sixty bacteria were isolated from an endotracheal aspirate of hospitalized patients. The different isolates were cultured followed by running biochemical tests, sensitivity assays, and automated VITEK®2 System analysis. Unexpectedly, all the isolates were Gram-negative bacteria. Klebsiella pneumoniae were the main pathogen encountered (27/60 isolates) followed by Acientobacter baumannnii (7/60) and other microorganisms belonging to the genera Moraxella, Escherichia, and Pseudomonas (11/60). Antibiotic sensitivity testing was performed via the VITEK®2 System using up to 16 different antibiotics representing 8 different antibiotic classes and subclasses (aminoglycosides, carbapenems, fluoroquinolones, penicillin/β-lactamase inhibitor, extended-spectrum cephalosporins, aminopenicillins, aminopenicillins/β-lactamase inhibitor, folic acid synthesis inhibitor). Majority of the isolates (28/60) showed a remarkable extensive drug resistance (XDR) pattern, while 15 isolates were multi-drug resistant (MDR) and only 6 were pan-drug resistant (PDR) with regard to antibiotics under evaluation.

Conclusion

The association of VAP with multi-drug-resistant bacteria is alarming, and rapid management is crucial. Identification of core pathogens is essential for identifying the most appropriate technique for infection control.

Ten-year surveillance study of ventilator-associated pneumonia at a tertiary care center in Lebanon

BACKGROUND

Ventilator-associated pneumonia (VAP) is associated with significant adverse outcomes in critically-ill patients admitted to the Intensive Care Unit (ICU). Systematic data from Lebanon on VAP are not available and large epidemiological studies from the region are scarce.

METHODS

We conducted a retrospective study over a 10-year period at the American University of Beirut Medical Center (AUBMC), a tertiary referral center in Lebanon in order to describe the incidence, microbiology, and temporal trends of VAP in the medical/surgical ICU.

RESULTS

A total of 162 patients developed VAP over the study period and the overall incidence of VAP was 7.9 per 1000 ventilator-days. There was a statistically significant decrease over time in the incidence of VAP, from 13.1 in 2008 to 1.1 per 1000 ventilator-days in 2017. Multidrug-resistant (MDR) Acinetobacter spp. was the predominant pathogen, both in early- as well as late-onset VAP, followed by Pseudomonas aeruginosa.

CONCLUSIONS

Following significant efforts from the Infection Control and Prevention Program, a considerable reduction in the incidence of VAP was achieved at AUBMC. The predominance of MDR Acinetobacter spp. should be taken into consideration when deciding on empirical therapy in patients with VAP.

Postoperative infection caused by Acinetobacter baumannii misdiagnosed as a free-living amoeba species in a humeral head hemiarthroplasty patient: a case report

BACKGROUND

Acinetobacter baumannii is ubiquitous, facultative intracellular, and opportunistic bacterial pathogen. Its unique abilities allow it to survive in a diverse range of environments, including health care settings, leading to nosocomial infections. And its exceptional ability to develop resistance to multiple antibiotics leaves few drug options for treatment. It has been recognized as a leading cause of nosocomial pneumonia and bacteremia over the world.

CASE PRESENTATION

In this case, a 73-year-old woman presented with a Neer Group VI proximal humeral fracture. Six hours after a successfully performed hemiarthroplasty, she developed continuous fever. Clinical examination revealed that the vitals were regular. Laboratory and radiographic examinations revealed only elevated procalcitonin levels. Blood culture revealed no bacterial or fungal growth. Cooling treatment and empirical broad-spectrum antibiotic therapy showed no apparent effect.

CONCLUSIONS

We report a postoperative infection caused by Acinetobacter baumannii. The infectious pathogen was identified via molecular DNA sequencing and was initially misidentified as a free-living amoeba species upon microscopic examinations. The patient was mistreated with antiamebic combination therapy. Her symptoms persisted for over 4 months and were eventually followed by her death.

World-Wide Variation in Incidence of Staphylococcus aureus Associated Ventilator-Associated Pneumonia: A Meta-Regression

Staphylococcus aureus (S. aureus) is a common Ventilator-Associated Pneumonia (VAP) isolate. The objective here is to define the extent and possible reasons for geographic variation in the incidences of S. aureus-associated VAP, MRSA-VAP and overall VAP. A meta-regression model of S. aureus-associated VAP incidence per 1000 Mechanical Ventilation Days (MVD) was undertaken using random effects methods among publications obtained from a search of the English language literature. This model incorporated group level factors such as admission to a trauma ICU, year of publication and use of bronchoscopic sampling towards VAP diagnosis. The search identified 133 publications from seven worldwide regions published over three decades. The summary S. aureus-associated VAP incidence was 4.5 (3.9–5.3) per 1000 MVD. The highest S. aureus-associated VAP incidence is amongst reports from the Mediterranean (mean; 95% confidence interval; 6.1; 4.1–8.5) versus that from Asian ICUs (2.1; 1.5–3.0). The incidence of S. aureus-associated VAP varies by up to three-fold (for the lowest versus highest incidence) among seven geographic regions worldwide, whereas the incidence of VAP varies by less than two-fold. Admission to a trauma unit is the most important group level correlate for S. aureus-associated VAP.

Unusually High Incidences of Staphylococcus aureus Infection within Studies of Ventilator Associated Pneumonia Prevention Using Topical Antibiotics: Benchmarking the Evidence Base

Selective digestive decontamination (SDD, topical antibiotic regimens applied to the respiratory tract) appears effective for preventing ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients. However, potential contextual effects of SDD on Staphylococcus aureus infections in the ICU remain unclear. The S. aureus ventilator associated pneumonia (S. aureus VAP), VAP overall and S. aureus bacteremia incidences within component (control and intervention) groups within 27 SDD studies were benchmarked against 115 observational groups. Component groups from 66 studies of various interventions other than SDD provided additional points of reference. In 27 SDD study control groups, the mean S. aureus VAP incidence is 9.6% (95% CI; 6.9–13.2) versus a benchmark derived from 115 observational groups being 4.8% (95% CI; 4.2–5.6). In nine SDD study control groups the mean S. aureus bacteremia incidence is 3.8% (95% CI; 2.1–5.7) versus a benchmark derived from 10 observational groups being 2.1% (95% CI; 1.1–4.1). The incidences of S. aureus VAP and S. aureus bacteremia within the control groups of SDD studies are each higher than literature derived benchmarks. Paradoxically, within the SDD intervention groups, the incidences of both S. aureus VAP and VAP overall are more similar to the benchmarks.

An antibiotic stewardship exercise in the ICU: building a treatment algorithm for the management of ventilator-associated pneumonia based on local epidemiology and the 2016 Infectious Diseases Society of America/American Thoracic Society guidelines

Introduction

Management of ventilator-associated pneumonia (VAP), the most common infection in patients on mechanical ventilation, should be tailored to local microbiological data. The aim of this study was to determine susceptibility patterns of organisms causing VAP to develop a treatment algorithm based on these findings and evidence from the literature.

Materials and methods

This is a retrospective analysis of the microbiological etiology of VAP in the intensive care unit (ICU) of a Lebanese tertiary care hospital from July 2015 to July 2016. We reviewed the latest clinical practice guidelines on VAP and tried to adapt these recommendations to our setting.

Results

In all, 43 patients with 61 VAP episodes were identified, and 75 bacterial isolates caused VAP. Extensively drug-resistant (XDR) Acinetobacter baumannii was the most common organism (37%), and it had occurred endemically throughout the year. Pseudomonas aeruginosa was the next most common organism (31%), and 13% were XDR. Enterobacteriaceae (15%) and Stenotrophomonas maltophilia (12%) shared similar incidences. Our algorithm was based on guidelines, in addition to trials, systematic reviews, and meta-analyses that studied the effectiveness of available antibiotics in treating VAP.

Conclusion

Knowing that resistance can rapidly develop within a practice environment, more research is needed to identify the best strategy for the management of VAP.

World-wide variation in incidence of Acinetobacter associated ventilator associated pneumonia: a meta-regression

Background

Acinetobacter species such as Acinetobacter baumanii are of increasing concern in association with ventilator associated pneumonia (VAP). In the ICU, Acinetobacter infections are known to be subject to seasonal variation but the extent of geographic variation is unclear. The objective here is to define the extent and possible reasons for geographic variation for Acinetobacter associated VAP whether or not these isolates are reported as Acinetobacter baumanii.

Methods

A meta-regression model of VAP associated Acinetobacter incidence within the published literature was undertaken using random effects methods. This model incorporated group level factors such as proportion of trauma admissions, year of publication and reporting practices for Acinetobacter infection.

Results

The search identified 117 studies from seven worldwide regions over 29 years. There is significant variation in Acinetobacter species associated VAP incidence among seven world-wide regions. The highest incidence is amongst reports from the Middle East (mean; 95 % confidence interval; 8.8; 6 · 2–12 · 7 per 1000 mechanical ventilation days) versus that from North American ICU’s (1 · 2; 0 · 8–2 · 1). There is a similar geographic related disparity in incidence among studies reporting specifically as Acinetobacter baumanii. The incidence in ICU’s with a majority of admission being for trauma is >2.5 times that of other ICU’s.

Conclusion

There is greater than fivefold variation in Acinetobacter associated VAP among reports from various geographic regions worldwide. This variation is not explainable by variations in rates of VAP overall, admissions for trauma, publication year or Acinetobacter reporting practices as group level variables.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1921-4) contains supplementary material, which is available to authorized users.

Frequency of hospital acquired pneumonia and its microbiological etiology in medical intensive care unit

OBJECTIVE

The objectives were to assess the frequency of hospital acquired pneumonia (HAP) in patients admitted to intensive care unit (ICU) and to determine the frequencies of different etiological organisms in these patients.

METHODS

This was descriptive cross sectional study, which was carried out in medical ICU of Shifa International Hospital Islamabad from January 2013 to January 2014. A total of 1866 patients were admitted in the department of medicine including medical ICU. They were evaluated for HAP and the causative organisms were cultured from these patients. Identification was carried out by standard biochemical profile of the organisms.

RESULTS

The total number of patients admitted in medical ICU for any reason were 346. HAP was diagnosed in 88 patients (25.4%). The average age of patients admitted in Medical ICU with HAP was 48 years with the range of 16 to 82 years. 56 were male and 32 females. 42 patients (47.7%) died in medical ICU with HAP. Microbiological analysis showed that Pseudomonas aeruginosa were 27 (30.6%), Acinetobacter spp. were 12 (13.6%), Candida albicans were 12 (13.6%), Klebsiellapneumoniae were 9 (10.2%), Streptococcus spp. were 9 (10.2%), Escherichia coli were 5 (5.6%), Stenotrophomonas spp. were 4(4.5%), Methicillin Resistant Staphylococcus Aureus (MRSA) were 4 (4.5%) others organisms 6 (6.8%).

CONCLUSION

The frequency of HAP in Medical ICU of our hospital is 88 out of 346 (25.4%). The commonest organism identified was Pseudomonas aeruginosa (30.6%) followed by Acinetobacter and Candida albican (13.6% each).

Risk factors of multidrug-resistant Acinetobacter baumannii recurrence after successful eradication in ventilated patients

Background

Clinically, multidrug-resistant Acinetobacter baumannii (MDR-AB) recurrence is found in some patients although identified as successfully eradicated. We aim to discover the characteristics of patients with MDR-AB recurrence in the respiratory tract.

Methods

We retrospectively collected 106 chronic respiratory failure patients with MDR-AB harvest in pulmonary secretion culture.

Results

MDR-AB was successfully eradicated in 69 patients. Diabetes mellitus (p = 0.030, odds ratio [OR]: 2.7, 95% confidence interval [CI]: 1.1–6.4) and acute respiratory distress syndrome (p = 0.001, OR = 4.8, 95% CI: 1.8–12.7) reduce the MDR-AB eradication rate. Besides, a classification of colonization or infection was made beyond the 69 MDR-AB eradicated patients. In the colonization group, diabetes mellitus (p = 0.009; OR = 5.1, 95% CI: 1.5–17.6) is the only independent factor to increase the recurrence rate. Glycated hemoglobin level is also analyzed for each group to investigate diabetes control effect, but no significant difference found.

Conclusions

Diabetes mellitus is a risk factor of MDR-AB recurrence among MDR-AB-colonized patients; the impact of localized pneumonia patch in MDR-AB-infected patients requires further study to be clarified.

National Survey of Thai Infectious Disease Physicians on Treatment of Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia: The Role of Infection Control Awareness

OBJECTIVE To evaluate the expected and treatment outcomes of Thai infectious disease physicians (IDPs) regarding carbapenem-resistant Acinetobacter baumannii (CRAB) ventilator-associated pneumonia (VAP) METHODS From June 1, 2014, to March 1, 2015, survey data regarding the expected and clinical success rates of CRAB VAP treatment were collected from all Thai IDPs. The expected success rate was defined as the expectation of clinical response after CRAB VAP treatment for the given case scenario. Clinical success rate was defined as the overall reported success rate of CRAB VAP treatment based on the clinical practice of each IDP. The expected and clinical success rates were divided into low (80%) categories and were then compared with standard clinical response rates archived in the existing literature. RESULTS Of 183 total Thai IDPs, 111 (60%) were enrolled in this study. The median expected and clinical success rates were 68% and 58%, respectively. Using multivariate analysis, we determined that working in a hospital that implemented the standard intervention combined with an intensified infection control (IC) intervention for CRAB (adjusted odds ratio [aOR], 3.01; 95% confidence interval [CI], 1.17-7.73; P=.02) was associated with standard and high expected rates (>60%). Being a board-certified IDP (aOR, 5.76; 95% CI, 2.16-15.37; P60%). We identified a significant correlation between expected and clinical success rates (r=0.58; P<.001). CONCLUSIONS Awareness of IC among IDPs can improve physicians' expected and clinical success rates for CRAB VAP treatment, and treatment experience impacts overall treatment success. Infect. Control Hosp. Epidemiol. 2015;37(1):61-69.

COPD patients with ventilator-associated pneumonia: implications for management

Data on the occurrence and outcome of patients with chronic obstructive pulmonary disease (COPD) and ventilator-associated pneumonia (VAP) are quite limited. The aim of this study was to determine if COPD intensive care unit (ICU) patients have a higher rate of VAP development, different microbiological aetiology or have worse outcomes than other patients without VAP. A secondary analysis of a large prospective, observational study conducted in 27 European ICUs was carried out. Trauma patients were excluded. Of 2082 intubated patients included in the study, 397 (19.1%) had COPD; 79 (19.9%) patients with COPD and 332 (19.7%) patients without COPD developed VAP. ICU mortality increased by 17% (p < 0.05) when COPD patients developed VAP, remaining an independent predictor of mortality [odds ratio (OR) 2.28; 95% confidence interval (CI) 1.35-3.87]. The development of VAP in COPD patients was associated with a median increase of 12 days in the duration of mechanical ventilation and >13 days in ICU stay (p < 0.05). Pseudomonas aeruginosa was more common in VAP when COPD was present (29.1% vs. 18.7%, p = 0.04) and was the most frequent isolate in COPD patients with early-onset VAP, with a frequency 2.5 times higher than in patients without early-onset VAP (33.3% vs. 13.3%, p = 0.03). COPD patients are not more predisposed to VAP than other ICU patients, but if COPD patients develop VAP, they have a worse outcome. Antibiotic coverage for non-fermenters needs to be included in the empiric therapy of all COPD patients, even in early-onset VAP.

Resistance of Gram-Negative Bacilli in Lebanon

Several studies have reported the isolation of resistant Gram-Negative Bacilli in Lebanon. However, those studies are new and scarce as compared to worldwide data and mostly restricted to single center studies. In this review, we attempt to provide a reliable and comprehensive report describing the current situation and providing prospects for bacterial resistance in Lebanon. Several studies have shown that Extended Spectrum β-Lactamase-producing E. coli and K. pneumoniae strains are being increasingly reported. Moreover, 2.15% of E. coli and 7.84% of K. pneumoniae isolates have shown carbapenem resistance and up to 30% of isolated E. coli strains were found to be Multi-Drug Resistant. Molecular studies showed that the most widespread β-Lactamases in Lebanon are of the CTX-M-15 and SHV types. In addition, K. pneumoniae strains producing metallo-β-Lactamase and Klebsiella pneumoniae Carbapenemase have been reported. Resistant Pseudomonas aeruginosa and Acinetobacter baumannii caused several nosocomial infections and some Acinetobacter baumannii strains were found to produce OXA-58 type ESBL. The few data addressing the rate of antibiotic consumption in Lebanon show a high rate of antibiotic misuse and abuse. In conclusion, there is a need for antibiotic stewardship programs and additional studies that go beyond the scope of single-center studies in Lebanon.

Burden of endemic health-care-associated infection in developing countries: systematic review and meta-analysis

BACKGROUND

Health-care-associated infection is the most frequent result of unsafe patient care worldwide, but few data are available from the developing world. We aimed to assess the epidemiology of endemic health-care-associated infection in developing countries.

METHODS

We searched electronic databases and reference lists of relevant papers for articles published 1995-2008. Studies containing full or partial data from developing countries related to infection prevalence or incidence-including overall health-care-associated infection and major infection sites, and their microbiological cause-were selected. We classified studies as low-quality or high-quality according to predefined criteria. Data were pooled for analysis.

FINDINGS

Of 271 selected articles, 220 were included in the final analysis. Limited data were retrieved from some regions and many countries were not represented. 118 (54%) studies were low quality. In general, infection frequencies reported in high-quality studies were greater than those from low-quality studies. Prevalence of health-care-associated infection (pooled prevalence in high-quality studies, 15·5 per 100 patients [95% CI 12·6-18·9]) was much higher than proportions reported from Europe and the USA. Pooled overall health-care-associated infection density in adult intensive-care units was 47·9 per 1000 patient-days (95% CI 36·7-59·1), at least three times as high as densities reported from the USA. Surgical-site infection was the leading infection in hospitals (pooled cumulative incidence 5·6 per 100 surgical procedures), strikingly higher than proportions recorded in developed countries. Gram-negative bacilli represented the most common nosocomial isolates. Apart from meticillin resistance, noted in 158 of 290 (54%) Staphylococcus aureus isolates (in eight studies), very few articles reported antimicrobial resistance.

INTERPRETATION

The burden of health-care-associated infection in developing countries is high. Our findings indicate a need to improve surveillance and infection-control practices.

FUNDING

World Health Organization.

Paradoxical ventilator associated pneumonia incidences among selective digestive decontamination studies versus other studies of mechanically ventilated patients: benchmarking the evidence base

Introduction

Selective digestive decontamination (SDD) appears to have a more compelling evidence base than non-antimicrobial methods for the prevention of ventilator associated pneumonia (VAP). However, the striking variability in ventilator associated pneumonia-incidence proportion (VAP-IP) among the SDD studies remains unexplained and a postulated contextual effect remains untested for.

Methods

Nine reviews were used to source 45 observational (benchmark) groups and 137 component (control and intervention) groups of studies of SDD and studies of three non-antimicrobial methods of VAP prevention. The logit VAP-IP data were summarized by meta-analysis using random effects methods and the associated heterogeneity (tau²) was measured. As group level predictors of logit VAP-IP, the mode of VAP diagnosis, proportion of trauma admissions, the proportion receiving prolonged ventilation and the intervention method under study were examined in meta-regression models containing the benchmark groups together with either the control (models 1 to 3) or intervention (models 4 to 6) groups of the prevention studies.

Results

The VAP-IP benchmark derived here is 22.1% (95% confidence interval; 95% CI; 19.2 to 25.5; tau² 0.34) whereas the mean VAP-IP of control groups from studies of SDD and of non-antimicrobial methods, is 35.7 (29.7 to 41.8; tau² 0.63) versus 20.4 (17.2 to 24.0; tau² 0.41), respectively (P < 0.001). The disparity between the benchmark groups and the control groups of the SDD studies, which was most apparent for the highest quality studies, could not be explained in the meta-regression models after adjusting for various group level factors. The mean VAP-IP (95% CI) of intervention groups is 16.0 (12.6 to 20.3; tau² 0.59) and 17.1 (14.2 to 20.3; tau² 0.35) for SDD studies versus studies of non-antimicrobial methods, respectively.

Conclusions

The VAP-IP among the intervention groups within the SDD evidence base is less variable and more similar to the benchmark than among the control groups. These paradoxical observations cannot readily be explained. The interpretation of the SDD evidence base cannot proceed without further consideration of this contextual effect.

Respiratory infections due to drug-resistant bacteria

Pneumonia is the most common infection that is the leading cause of death. The increasing antimicrobial resistance in major respiratory pathogens such as Streptococcus pneumoniae, Staphylococcus aureus and gram-negative bacteria has severely restricted the treatment options. Respiratory infections caused by multidrug-resistant bacteria are associated with a greater likelihood of inappropriate antimicrobial therapy and poor clinical outcome. Especially, treatment of infections caused by pandrug-resistant gram-negative bacteria is a major challenge. Continuous efforts to control the global spread of drug-resistant bacteria are essential.

Trauma sepsis

Sepsis is a major cause of mortality and morbidity in the trauma patient. Sepsis following traumatic injury is related to the type of injury, together with the extent of injury and the anatomical location. Burn injuries are associated with the highest risk of sepsis. The diagnosis of sepsis in the trauma patient remains difficult. Interpretation of abnormal results is key to successful diagnosis, particularly in conjunction with clinical findings. This review will consider the specific features of sepsis in the context of trauma relating to epidemiology, risk factors, diagnosis and management.

Ventilator-associated pneumonia and mortality: a systematic review of observational studies

OBJECTIVE

To determine the attributable mortality of ventilator-associated pneumonia in a systematic review and meta-analysis of observational studies. Ventilator-associated pneumonia is generally believed to increase the mortality of patients. This notion is predominantly based on the results of observational studies.

DATA SOURCE

We performed a systematic search strategy using PubMed, Web of Science, and Embase from their inception through February 2007. In addition, a reference and related article search was performed.

STUDY SELECTION

Studies were included if they reported mortality rates of patients with and without ventilator-associated pneumonia.

DATA EXTRACTION AND SYNTHESIS

Fifty-two studies with a total of 17,347 patients met the inclusion criteria. Pooling of all studies resulted in relative risk of 1.27 (95% Confidence Interval = 1.15-1.39), but heterogeneity was considerable (I2 statistic = 69%). The origin of heterogeneity could not be explained by differences in study design, study quality, and diagnostic approach. However, heterogeneity was limited for studies investigating only trauma patients (I2 = 1.3%) or patients with acute respiratory distress syndrome (I2 = 0%), with estimated relative risk of 1.09 (95% Confidence Interval = 0.87-1.37) among trauma patients and 0.86 (95% Confidence Interval = 0.72-1.04) among patients with acute respiratory distress syndrome.

CONCLUSIONS

There is no evidence of attributable mortality due to ventilator-associated pneumonia in patients with trauma or acute respiratory distress syndrome. However, in other nonspecified patient groups, there is evidence for attributable mortality due to ventilator-associated pneumonia, but this could not be quantified due to heterogeneity in study results. More detailed studies, allowing subgroup analyses, are needed to determine the attributable mortality of ventilator-associated pneumonia in these patient populations.

Hospital-acquired device-associated infections at a deployed military hospital in Iraq

BACKGROUND

To date, there have been no published studies describing rates of device-associated infections over extended periods at deployed military hospitals. We describe the rates of utilization and device-associated infections at the Air Force Theater Hospital (AFTH) in Iraq.

METHODS

This is a retrospective review of infection control (IC) records at the AFTH intensive care unit (ICU) from November 2006 through December 2007. Monthly device utilization and infection rates (per 1000 device days) were analyzed for trend and compared with pooled means for US trauma ICUs.

RESULTS

Central line utilization rates were constant (mean, 64%) with central line- associated bloodstream infection (CLAB) rates of 0 to 7.7 (US rate 4.6) except from September to December 2007, when the rate ranged from 7.4 to 29.3. An IC program reduced ventilator-associated pneumonia (VAP) rates to a baseline of 9.7 to 11.6. However, VAP rates rose to 13.3 to 56.3 in the 4-month period of January through April 2007 and 14.3 to 28.2 during September through December 2007. Neither CLAB nor VAP rates correlated with ICU admissions. The urinary catheter-associated urinary tract infection rate was 0 to 6.7 (US rate 5.5). Overall, Staphylococcus aureus was the predominant organism during May through October 2007 and Acinetobacter in November and December 2007.

CONCLUSIONS

Substantial variability exists in the rates of CLAB and VAP in the AFTH. Potential explanations are staff turnover and prolonged stays among non-US personnel who may serve as a reservoir for ongoing infections. Identification of barriers to IC may help inform the process of creating and implementing effective IC strategies in deployed military hospitals.

Alpha-toxin facilitates the generation of CXC chemokine gradients and stimulates neutrophil homing in Staphylococcus aureus pneumonia

BACKGROUND

Staphylococcus aureus alpha-toxin is a major virulence factor, but its mechanism of action in vivo is incompletely understood.

METHODS

We examined the role of alpha-toxin in S. aureus pneumonia using the mouse model of intranasal lung infection with S. aureus strain 8325-4 (hla(+) S. aureus) and an alpha-toxin-deficient mutant strain made on the 8325-4 background (hla(-) S. aureus).

RESULTS

Intranasal infection of mice with hla(-) S. aureus resulted in substantially less lung injury and inflammation, pulmonary edema, and tissue bacterial burden than did infection with hla(+) S. aureus. Furthermore, fewer mice infected with hla(-) S. aureus died of the infection, compared with those infected with hla(+) S. aureus. Levels of the CXC chemokines keratinocyte-derived chemokine and macrophage inflammatory protein-2 were significantly lower in the airways of mice infected with hla(-) S. aureus, and this difference was the result of reduced secretion of newly synthesized chemokines into the airway. Consistent with these data, significantly fewer neutrophils were present in the airways and lungs of mice infected with hla(-) S. aureus, compared with those infected with hla(+) S. aureus.

CONCLUSIONS

These data suggest that alpha-toxin enhances virulence by facilitating the generation of CXC chemokine gradients and stimulating chemokine-induced neutrophil influx in S. aureus pneumonia.

Infectious disease complications of combat-related injuries

BACKGROUND

: Strategies currently used to prevent morbidity and mortality associated with combat-related injuries include better training of frontline medical personnel, improved personal protective equipment, and deployment of fast-forward surgical assets with state-of-the-art equipment. These strategies allow patients to survive near-catastrophic injuries, placing a greater emphasis on the medical infrastructure to mitigate short- and long-term complications associated with these injuries.

DISCUSSION

: Wounds have certain characteristics that promote the development of infections: the presence of devitalized tissue, foreign bodies, clots, fluid collections, and contamination of wounds with bacteria from the casualty's skin, the environment, and the hospital. All of these factors culminate in placing the casualty at risk of developing an infection.

SUMMARY

: This article reviews the lessons learned from combat-related wound infections throughout history and in the current conflicts in Iraq and Afghanistan. Many of the management strategies used to prevent infections of combat-related injuries are applicable to the management of civilian trauma, whether associated with small arms fire or related to natural disasters such as earthquakes or tornadoes.

Multidrug-resistant organisms in military wounds from Iraq and Afghanistan

Mortality from battlefield wounds has historically declined, thanks to better surgical management, faster transport of casualties, and improved antibiotics. Today, one of the major challenges facing U.S. military caregivers is the presence of multidrug-resistant organisms in orthopaedic extremity wounds. The most frequently identified resistant strains of bacteria are Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter calcoaceticus-baumannii complex. Overuse of broad-spectrum antibiotics may be an important factor in building resistant strains. Acinetobacter infections appear to hospital-acquired and not from an initial colonization of the injury. More research is required to give military physicians the tools they require to reduce the infection rate and defeat multidrug-resistant organisms.

Ventilator-associated pneumonia in adults in developing countries: a systematic review

BACKGROUND

Ventilator-associated pneumonia (VAP) is a leading cause of death in hospitalized patients, but there has been no systematic analysis of the incidence, microbiology, and outcome of VAP in developing countries or of the interventions most applicable in that setting.

METHODS

We reviewed MEDLINE (January 1966-April 2007) and bibliographies of the retrieved articles for all observational or interventional studies that examined the incidence, microbiology, outcome, and prevention of VAP in ventilated adults in developing countries. We evaluated the rates of VAP using the National Healthcare Safety Network (NHSN) definitions and the impact of VAP on the intensive care unit (ICU) length of stay (LOS) and mortality, and the impact of interventions used to reduce VAP rates.

RESULTS

The rates of VAP varied from 10 to 41.7 per 1000 ventilator-days and were generally higher than NHSN benchmark rates. Gram-negative bacilli were the most common pathogens (41-92%), followed by Gram-positive cocci (6-58%). VAP was associated with a crude mortality that ranged from 16% to 94% and with increased ICU LOS. Only a small number of VAP intervention studies were performed; these found that staff education programs, implementation of hand hygiene, and VAP prevention practice guidelines, and/or implementation of sedation protocol were associated with a significant reduction in VAP rates. Only one interventional study was a randomized controlled trial comparing two technologies, the rest were sequential observational. This study compared a heat and moisture exchanger (HME) to a heated humidifying system (HHS) and found no difference in VAP rates.

CONCLUSIONS

Based on the existing literature, the rate of VAP in developing countries is higher than NHSN benchmark rates and is associated with a significant impact on patient outcome. Only a few studies reported successful interventions to reduce VAP. There is a clear need for additional epidemiologic studies to better understand the scope of the problem. Additionally, more work needs to be done on strategies to prevent VAP, probably with emphasis on practical, low-cost, low technology, easily implemented measures.

Epidemiology of infections associated with combat-related injuries in Iraq and Afghanistan

Enhanced medical training of front line medical personnel, personal protective equipment, and the presence of far forward surgical assets have improved the survival of casualties in the current wars in Iraq and Afghanistan. As such, casualties are at higher risk of infectious complications of their injuries including sepsis, which was a noted killer of casualties in previous wars. During the current conflicts, military personnel who develop combat-related injuries are at substantial risk of developing infections with multidrug resistant bacteria. Herein, we describe the bacteriology of combat-related injuries in Operation Iraqi Freedom and Operation Enduring Freedom that develop infections with particular attention to injuries of the extremities, central nervous system, abdomen and thorax, head and neck, and burns. In addition, the likely sources of combat-related injuries with multidrug resistant bacteria infections are explored.

Acinetobacter infections: a growing threat for critically ill patients

There has been increasing concern regarding the rise of Acinetobacter infections in critically ill patients. We extracted information regarding the relative frequency of Acinetobacter pneumonia and bacteraemia in intensive-care-unit (ICU) patients and the antimicrobial resistance of Acinetobacter isolates from studies identified in electronic databases. Acinetobacter infections most frequently involve the respiratory tract of intubated patients and Acinetobacter pneumonia has been more common in critically ill patients in Asian (range 4-44%) and European (0-35%) hospitals than in United States hospitals (6-11%). There is also a gradient in Europe regarding the proportion of ICU-acquired pneumonias caused by Acinetobacter with low numbers in Scandinavia, and gradually rising in Central and Southern Europe. A higher proportion of Acinetobacter isolates were resistant to aminoglycosides and piperacillin/tazobactam in Asian and European countries than in the United States. The data suggest that Acinetobacter infections are a growing threat affecting a considerable proportion of critically ill patients, especially in Asia and Europe.

Incidence and risk factors for ventilator-associated pneumonia in a developing country: Where is the difference?

BACKGROUND

Latin America exhibits a wide range of differences, compared to developed nations, in genetic background, health services, and clinical research development. It is valid to hypothesize that the incidence and risk factors for ventilator-associated pneumonia (VAP) in our setting may be substantially different of those reported elsewhere. We conducted a study to determine the incidence and risk factors for VAP in a University Hospital from Medellin, Colombia.

METHODS

Prospective cohort study in three intensive care units (ICU) (surgical/trauma, medical, cardiovascular) in a 550-bed University Hospital. Critically ill patients (n=270) who required at least 48 h of mechanical ventilation (MV) between June 2002 and October 2003 were followed until ICU discharge, VAP diagnosis or death.

RESULTS

Sixty patients (22.2%) developed VAP 5.9+/-3.6 days after admission. The overall incidence of VAP was 29 cases per 1000 ventilator-days. The daily hazard for developing VAP increased until day 8, and then decreased over the duration of stay in the ICU. The only statistically significant factor after multivariable analysis was gender, with being female reducing 57% the risk of pneumonia (hazard ratios (HR): 0.43; 95% confidence intervals (CI): 0.19-0.96).

CONCLUSIONS

The epidemiologic profile of VAP in terms of incidence, length of stay and clinical course resembles the general pattern described everywhere. Surprisingly, we could not identify any potentially modifiable risk factor for VAP. A comprehensive multicenter study is warranted. It should provide deep insight about the specific microbiological, genetic and clinic features of VAP in our setting.

Attributable mortality of Acinetobacter baumannii infections in critically ill patients: a systematic review of matched cohort and case-control studies

INTRODUCTION

There has been a continuing controversy about whether infection with Acinetobacter baumannii increases morbidity and mortality independently of the effect of other confounding factors.

METHODS

We performed a systematic review of matched case-control and cohort studies examining the mortality attributable to infection with or acquisition of A. baumannii (infection or colonization). We included in our review studies that compared mortality and/or morbidity of patients with acquisition of or infection with A. baumannii (cases) with the outcomes of matched patients without A. baumannii isolation from clinical specimens (controls). The relevant studies were identified from searches of the PubMed and the Cochrane Library databases. Two independent reviewers performed the literature search, study selection, and data extraction from nine identified relevant studies.

RESULTS

The attributable mortalities, in the hospital and in the intensive care unit, of patients with A. baumannii infection in six matched case-control studies included in our review ranged from 7.8% to 23% and from 10% to 43%, respectively. In addition, a statistically significantly higher mortality was reported for patients with A. baumannii acquisition; that is, colonization or infection (cases) compared with controls without such an acquisition in all four reviewed studies that reported data on this comparison.

CONCLUSION

Although definitive statements about the mortality attributable to the acquisition of A. baumannii cannot be made from the available studies because of their methodological heterogeneity, the reviewed data suggest that infection with or acquisition of A. baumannii seems to be associated with increased mortality.

Clinical and economic consequences of ventilator-associated pneumonia: a systematic review

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in critically ill patients. The clinical and economic consequences of VAP are unclear, with a broad range of values reported in the literature

OBJECTIVE

To perform a systematic review to determine the incidence of VAP and its attributable mortality rate, length of stay, and costs.

DATA SOURCE

Computerized PUBMED and MEDLINE search supplemented by manual searches for relevant articles, limited to articles published after 1990.

STUDY SELECTION

English-language observational studies and randomized trials that provided data on the incidence of VAP were included. Matched cohort studies were included for calculation of attributable mortality rate and length of stay.

DATA EXTRACTION

Data were extracted on patient population, diagnostic criteria for VAP, incidence, outcome, type of intensive care unit, and study design.

DATA SYNTHESIS

The cumulative incidence of VAP was calculated by combining the results of several studies using standard formulas for combining proportions, in which the weighted average and variance are calculated. Results from studies comparing intensive care unit and hospital mortality due to VAP, additional length of stay, and additional days of mechanical ventilation were pooled using a random effects model, with assessment of heterogeneity.

RESULTS

Our findings indicate a) between 10% and 20% of patients receiving >48 hrs of mechanical ventilation will develop VAP; b) critically ill patients who develop VAP appear to be twice as likely to die compared with similar patients without VAP (pooled odds ratio, 2.03; 95% confidence interval, 1.16-3.56); c) patients with VAP have significantly longer intensive care unit lengths of stay (mean = 6.10 days; 95% confidence interval, 5.32-6.87 days); and d) patients who develop VAP incur > or = USD $10,019 in additional hospital costs.

CONCLUSIONS

Ventilator-associated pneumonia occurs in a considerable proportion of patients undergoing mechanical ventilation and is associated with substantial morbidity, a two-fold mortality rate, and excess cost. Given these findings, strategies that effectively prevent VAP are urgently needed.

Ventilator-associated pneumonia in a tertiary care ICU: analysis of risk factors for acquisition and mortality

OBJECTIVE

To investigate the incidence, risk factors and mortality of ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients.

DESIGN

Prospective, observational, population-based study.

SETTING

The medical (14-bed) and surgical ICU (26-bed) of the Ghent University Hospital.

METHODS

All 1295 patients admitted to the ICU during 4 three-month periods between 1996 and 1998 were included. A set of demographic and clinical variables were collected at the day of admission and during the ICU course.

RESULTS

The incidence of VAP among ICU patients ventilated at least 48 hours was 23.1%. The mean time to the development of VAP was 9.6 days with a median of 6 days. In the population of patients ventilated for at least 48 hours, a comparison was made between patients with (n = 89) and without VAP (n = 296). Patients with VAP had a significant longer ICU stay, with a longer ventilation dependency. Logistic regression analysis identified admission diagnosis other than trauma (OR: 0.51, 95% CI: 0.29-0.89; p = 0.02) and the length of ICU stay (OR: 1.05, 95% CI: 1.03-1.07; p < 0.001) to be independently associated with the acquisiton of VAP. In comparison with the total study population, patients with VAP had a higher ICU mortality (20.2% vs. 12.0%; p = 0.04), but not in the cohort group of patients at risk for VAP (ventilated > 48 hours)(20.2% vs. 31.3%; p = 0.03). The factors independently associated with death were higher SAPS II scores (OR 1.02, 95% CI: 1.003-1.032; p = 0.02), an admission diagnosis other than trauma (OR 0.36, 95% CI: 0.17-0.75; p = 0.006) and length of ICU stay (OR 0.97, 95% CI: 0.946-0.995; p = 0.02). This model did not recognize VAP as an independent predictor of death (OR 0.79, 95% CI: 0.41-1.53; p = 0.492).

CONCLUSIONS

The incidence of VAP in our ICU is 23.1%. Length of ICU stay and an admission diagnosis other than trauma are major risk factors for the development of this nosocomial infection. VAP is associated with a high fatality rate. However, after adjustment for disease severity and length of ICU stay, VAP was not identified as an independent predictor of death.

Ventilator-associated pneumonia

PURPOSE OF REVIEW

This review summarises some of the notable papers on ventilator-associated pneumonia (VAP) from January 2003 to October 2004.

RECENT FINDINGS

Ventilator-associated pneumonia remains an important drain on hospital resources. All population groups are affected, but patients with VAP are more likely to be older, sicker, and male, with invasive medical devices in situ. Early VAP diagnosis is desirable to reduce VAP mortality and to retard emergence of multidrug-resistant microbes. This may be possible using preliminary culture results or intracellular organism in polymorphonuclear cells. In most intensive care units, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii are the commonest organisms isolated in VAP. However, causative organisms vary between and within hospitals. Consequently, individual intensive care units should develop empirical antibiotic policies to target the pathogenic bacteria prevalent in their patient populations. Preventative strategies aimed at reducing aerodigestive tract colonisation by pathogenic organisms, and also their subsequent aspiration, are becoming increasingly important. Educating medical staff about these simple measures is therefore pertinent. To reduce the occurrence of multidrug-resistant organisms, limiting the duration of antibiotic treatment to 8 days and antimicrobial rotation should be contemplated. Empirical therapy with antipseudomonal penicillins plus beta-lactamase inhibitors should be considered. If methicillin-resistant Staphylococcus aureus VAP is a possibility, linezolid may be better than vancomycin.

SUMMARY

Prevention remains the key to reducing VAP prevalence.

Ventilator-associated pneumonia in a pediatric intensive care unit in Saudi Arabia: a 30-month prospective surveillance

OBJECTIVE

To describe the rate, risk factors, and outcome of ventilator-associated pneumonia (VAP) in pediatric patients.

METHODS

This prospective surveillance study of VAP among all patients receiving mechanical ventilation for 48 hours or more admitted to a pediatric intensive care unit (PICU) in Saudi Arabia from May 2000 to November 2002 used National Nosocomial Infections Surveillance (NNIS) System definitions.

RESULTS

Three hundred sixty-one eligible patients were enrolled. Most were Saudi with a mean age of 28.6 months. Thirty-seven developed VAP. The mean VAP rate was 8.87 per 1,000 ventilation-days with a ventilation utilization rate of 47%. The mean duration of mechanical ventilation was 21 days for VAP patients and 10 days for non-VAP patients. The mean PICU stay was 34 days for VAP patients and 15 days for non-VAP patients. Among VAP patients, Pseudomonas aeruginosa was the most common organism, followed by Staphylococcus aureus. Other gram-negative organisms were also encountered. There was no significant difference between VAP and non-VAP patients regarding mortality rate. Witnessed aspiration, reintubation, prior antibiotic therapy, continuous enteral feeding, and bronchoscopy were associated with VAP. On multiple logistic regression analysis, only prior antibiotic therapy, continuous enteral feeding, and bronchoscopy were independent predictors of VAP.

CONCLUSIONS

The mean VAP rate in this hospital was higher than that reported by NNIS System surveillance of PICUs. This study has established a benchmark for future studies of VAP in the pediatric intensive care population in Saudi Arabia. Additional studies from the region are necessary for comparison and development of preventive measures.