Ventilator-associated pneumonias in a cardiothoracic surgery centre postoperative intensive care unit

The Existence of High Bacterial Resistance to Some Reserved Antibiotics in Tertiary Hospitals in Tanzania: A Call to Revisit Their Use

Background

Antibiotic resistance poses burden to the community and health-care services. Efforts are being made at local, national and global level to combat the rise of antibiotic resistance including antibiotic stewardship. Surveillance to antibiotic resistance is of importance to aid in planning and implementing infection prevention and control measures. The study was conducted to assess the resistance pattern to cefepime, clindamycin and meropenem, which are reserved antibiotics for use at tertiary hospitals in Tanzania.

Methods

A hospital-based antibiotic resistance surveillance was conducted between July and November 2019 at Muhimbili National Hospital and Bugando Medical Center, Tanzania. All organisms isolated were identified based on colony morphology, Gram staining and relevant biochemical tests. Antibiotic susceptibility testing was performed on Muller-Hinton agar using Kirby-Bauer disc diffusion method. Antibiotic susceptibility was performed according to the protocol by National Committee for Clinical Laboratory Standards.

Results

A total of 201 clinical samples were tested in this study. Urine (39.8%, n=80) and blood (35.3%, n=71) accounted for most of the collected samples followed by pus (16.9%, n=34). The bacterial resistance to clindamycin, cefepime and meropenem was 68.9%, 73.2% and 8.5%, respectively. About 68.4% Staphylococcus aureus isolates were resistant to clindamycin whereby 56.3%, 75.6%, 93.8% and 100% of the tested Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa and Enterobacter cloacae, respectively, were cefepime resistant. About 8.5% of isolated Klebsiella spp were resistant and 6.4% had intermediate susceptibility to meropenem. Also, Pseudomonas aeruginosa was resistant by 31.2% and 25% had intermediate susceptibility to meropenem.

Conclusion

The bacterial resistance to clindamycin and cefepime is high and low in meropenem. Henceforth, culture and susceptibility results should be used to guide the use of these antibiotics. Antibiotics with low resistance rate should be introduced to the reserve category and continuous antibiotic surveillance is warranted.

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.

Prognostic value of serum procalcitonin and C-reactive protein levels in critically ill patients who developed ventilator-associated pneumonia

INTRODUCTION:

Ventilator-associated pneumonia (VAP) is an important cause of mortality and morbidity in critically ill patients. We sought to determine the prognostic value of procalcitonin (PCT) and C-reactive protein (CRP) kinetics in critically ill patients who developed VAP.

METHODS:

Patients who were admitted to the intensive care unit (ICU) and developed VAP were eligible. Patients were followed for 28 days after the pneumonia diagnosis and blood samples for PCT and CRP were collected on the day of the pneumonia diagnosis (D0), and days 3 (D3) and 7 (D7) after the diagnosis. Patients were grouped as survivors and non-survivors, and the mean PCT and CRP values and their kinetics were assessed.

RESULTS:

In total, 45 patients were enrolled. Of them, 22 (48.8%) died before day 28 after the pneumonia diagnosis. There was no significant difference between the survivor and non-survivor groups in terms of PCT on the day of pneumonia diagnosis or CRP levels at any point. However, the PCT levels days 3 and 7 were significantly higher in the non-survivor group than the survivor group. Whereas PCT levels decreased significantly from D0 to D7 in the survivor group, CRP did not. A PCT level above 1 ng/mL on day 3 was the strongest predictor of mortality, with an odds ratio of 22.6.

CONCLUSION:

Serum PCT was found to be a superior prognostic marker compared to CRP in terms of predicting mortality in critically ill patients who developed VAP. The PCT level on D3 was the strongest predictor of mortality in VAP.

Hospital-acquired pneumonia in patients undergoing coronary artery bypass graft; comparison of the center for disease control clinical criteria with physicians' judgment

BACKGROUND

Following coronary artery bypass graft (CABG), patients are at high risk (3.2%-8.3%) for developing hospital-acquired pneumonia (HAP) with mortality rate of 24% to 50%. Some of routine features in patients undergoing CABG are similar to clinical criteria of Center of Disease Control (CDC) for diagnosis of pneumonia. This may lead to over-diagnosis of pneumonia in these patients.

OBJECTIVES

This study aimed to assess the frequency of CDC criteria for diagnosis of pneumonia in patients undergoing CABG.

PATIENTS AND METHODS

This study was performed on CABG candidates admitted to post cardiac surgery Intensive Care Unit (ICU) in a six-month period. Patient's records, Chest-X-Ray, and Laboratory tests were assessed for PNU1-CDC criteria for HAP diagnosis. At the same time, a physician who was unaware of the study protocol assessed the clinical diagnosis. Then the results were compared with CDC criteria-based diagnosis.

RESULTS

Of total 300 patients, 9 (3%) met CDC criteria for diagnosis of pneumonia while none of the cases were diagnosed as HAP according to the physicians' clinical diagnosis. All nine patients were discharged with proper general condition and no need of antibiotic therapy. This study showed that loss of consciousness, tachypnea, dyspnea, PaO2 < 60 mm Hg, PaO2/FiO2 < 240, and local infiltration in 24 hours of operation were misleading features of CDC criteria, which were not considered in physicians' clinical judgment to establish the diagnosis.

CONCLUSIONS

Our findings suggest that in Post-CABG patients, physicians could judge the occurrence of HAP more accurately in comparison to making the diagnosis based on CDC criteria alone. Expert physician may intentionally do not take some of these criteria into account according the patients' course of disease. Therefore, it is suggested that the value of these criteria in special group of patients like those undergoing CABG should be re-evaluated.

Improving Antibiotic De-Escalation in Suspected Ventilator-Associated Pneumonia: An Observational Study With a Pharmacist-Driven Intervention

BACKGROUND

Recommendations for treatment of ventilator-associated pneumonia (VAP) emphasize early empiric broad-spectrum antibiotics. However, appropriate antibiotic de-escalation is also critical for optimal patient care.

MATERIALS AND METHODS

We examined how often intensivists in our institution appropriately de-escalated antibiotics in cases of suspected VAP, and whether decision support by intensive care unit pharmacists could improve rates of antibiotic targeting and early antibiotic discontinuation in low-risk patients.

MAIN RESULTS

A total of 92 (observation phase = 50; intervention phase = 42) patients with suspected VAP were identified. During the observation phase, 39 cases yielded positive sputum cultures, but in only 23 (59%) were antibiotics targeted to culture results. This rate improved during the intervention phase when 29 (91%) of 32 cases with positive cultures were targeted (P value .003). There were 48 cases in which the risk of pneumonia was considered low. Of the 26 low-risk cases in the observation phase, 5 (19%) had antibiotics discontinued early versus 5 (23%) of the 22 cases in the intervention phase.

CONCLUSIONS

Decision support by clinical pharmacists significantly improved rates of appropriate antibiotic targeting in cases of culture-positive suspected VAP but did not have a significant effect on early antibiotic discontinuation in patients at low risk of true pneumonia.

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.

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.

Ventilator-associated pneumonia in patients undergoing major heart surgery: an incidence study in Europe

Introduction

Patients undergoing major heart surgery (MHS) represent a special subpopulation at risk for nosocomial infections. Postoperative infection is the main non-cardiac complication after MHS and has been clearly related to increased morbidity, use of hospital resources and mortality. Our aim was to determine the incidence, aetiology, risk factors and outcome of ventilator-associated pneumonia (VAP) in patients who have undergone MHS in Europe.

Methods

Our study was a prospective study of patients undergoing MHS in Europe who developed suspicion of VAP. During a one-month period, participating units submitted a protocol of all patients admitted to their units who had undergone MHS.

Results

Overall, 25 hospitals in eight different European countries participated in the study. The number of patients intervened for MHS was 986. Fifteen patients were excluded because of protocol violations. One or more nosocomial infections were detected in 43 (4.4%) patients. VAP was the most frequent nosocomial infection (2.1%; 13.9 episodes per 1000 days of mechanical ventilation). The microorganisms responsible for VAP in this study were: Enterobacteriaceae (45%), Pseudomonas aeruginosa (20%), methicillin-resistant Staphylococcus aureus (10%) and a range of other microorganisms. We identified the following significant independent risk factors for VAP: ascending aorta surgery (odds ratio (OR) = 6.22; 95% confidence interval (CI) = 1.69 to 22.89), number of blood units transfused (OR = 1.08 per unit transfused; 95% CI = 1.04 to 1.13) and need for re-intervention (OR = 6.65; 95% CI = 2.10 to 21.01). The median length of stay in the intensive care unit was significantly longer (P < 0.001) in patients with VAP than in patients without VAP (23 days versus 2 days). Death was significantly more frequent (P < 0.001) in patients with VAP (35% versus 2.3%).

Conclusions

Patients undergoing aortic surgery and those with complicated post-intervention courses, requiring multiple transfusions or re-intervention, constitute a high-risk group probably requiring more active preventive measures.

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.

Using a collaborative to reduce ventilator-associated pneumonia in Thailand

BACKGROUND

Ventilator-associated pneumonia (VAP) is a serious nosocomial infection, leading to high mortality and high costs of treatment in developed and limited-resource countries. A collaborative quality improvement (QI) project was conducted in 18 secondary and tertiary care hospitals in Thailand to address the problem.

METHODS

The project, conducted between February 2004 and May 2005, entailed three face-to-face meetings--two national workshops and two regional workshops (each conducted twice). Education on VAP prevention, including guidelines and the ventilator bundle, was conducted for intensive care unit staff and all relevant personnel. The collaborative's effectiveness was assessed by VAP rate, a self-administered questionnaire, and face-to-face interviews.

RESULTS

Within 12 months, the pooled VAP rate decreased from 13.3 to 8.3 per 1,000 ventilator-days. The costs of antibiotic treatment for VAP decreased by more than one half. More than 80% of interviewed participants reported that the QI method could be applied effectively in their organization.

DISCUSSION

VAP surveillance during this project revealed a gradual reduction of the VAP rate. The project's relative overall success appears to reflect, as reported elsewhere, a well-organized program, support from hospital administrators, and workshop leaders' presentation of proven QI methods and clinical interventions.

Thoracic organ transplantation may not increase the risk of bacterial transmission in intensive care units

A transmission study was performed to investigate whether organ recipients suffer more transmissions of bacteria than do non-transplanted patients. We chose enterococci for molecular typing because of their high prevalence, transmissibility, and predominance in causing nosocomial infections. Patients staying longer than 48h in a cardiovascular surgery intensive care unit (ICU) were included in our one-year prospective cohort study. Enterococci identified from clinical or surveillance isolates were collected and typed by PFGE. Episodes of transmission were defined by the identification of genetically indistinguishable isolates in two or more patients who were treated during overlapping intervals or within a 9-day window period in the same ICU. Risk factor analysis was performed. Out of 585 patients microbiological specimens were cultured from 336 patients. From 187 of these, enterococci were isolated. From 81 patients 186 enterococci isolates were typed. Out of 105 different enterococci strains, 16 cluster strains were detected and 30 episodes of transmissions occurred. The transmission rate was 7.8 per 1000 patient days. No significant association was found between "being cluster member "and "patient organ transplanted" (OR 1.5, CI(95%) 0.58; 3.98, p=0.38) or "patient treated in a single-room only" (OR 1.06, CI(95%) 0.36;3, 12, p=0.91), respectively. In contrast, "being cluster member" was associated with a prolonged length of stay (OR per additional days of stay 1.05, CI(95%) 1.01-1.09, p<0.01). Thoracic organ transplantation was not found to be a risk factor for bacterial transmission, but transmission was associated with a prolonged length of stay.

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 after heart surgery: a prospective analysis and the value of surveillance

OBJECTIVE

To determine the frequency, etiology, and risk factors of ventilator-associated pneumonia (VAP) and purulent tracheobronchitis (TBX) in patients who have undergone heart surgery. To study the predictive role of systematic surveillance cultures.

DESIGN

Prospective study.

SETTING

Heart surgery intensive care unit.

PATIENTS

Intubated heart surgical patients.

INTERVENTIONS

Systematic tracheal aspirate and protected brush catheter cultures of all intubated patients.

MEASUREMENTS AND MAIN RESULTS

Studied were the frequency of lower respiratory tract infection in ventilated patients and the role of surveillance cultures. The frequency of VAP was 7.87% (34.5 per 1,000 days of mechanical ventilation), and the criteria for purulent tracheobronchitis was fulfilled by 8.15% of patients (31.13 per 1,000 days of mechanical ventilation). After multivariate analysis, the variables independently associated with the development of respiratory tract infection were central nervous system disorder (relative risk [RR] = 4.7), ulcer disease (RR = 3.6), New York Heart Association score >/=3 (RR = 4), need for mechanical circulatory support (RR = 6.8), duration of mechanical ventilation >96 hrs (RR = 12.3), and reintubation (RR = 63.7). Mortality in our study was as follows: VAP patients, 57.1%; purulent tracheobronchitis patients, 20.7%; colonized patients, 11.5%; and noncolonized patients, 1.6%. Regular surveillance cultures were taken from all ventilated patients to assess the anticipative value of the cultures in predicting respiratory tract infection. A total of 1,626 respiratory surveillance samples were obtained. Surveillance cultures effectively predicted only one episode of VAP and one of tracheobronchitis.

CONCLUSIONS

Patients undergoing heart surgery have a high frequency of VAP. VAP is associated with a poor prognosis. In this study, surveillance cultures failed as an anticipative diagnostic method.

Ventilator-associated pneumonia: Incidence, risk factors, outcome, and microbiology

OBJECTIVE

To determine the incidence, risk factors, outcome, and pathogens of ventilator-associated pneumonia (VAP) in a cardiac surgical intensive care unit (ICU).

DESIGN

Prospective study.

SETTING

Escorts Heart Institute and Research Centre, New Delhi, India.

PARTICIPANTS

Nine hundred fifty-two consecutive patients undergoing cardiac operations who received intermittent positive-pressure ventilation (IPPV).

INTERVENTIONS

All patients were assigned into VAP (n = 25) and non-VAP (n = 927) groups.

MEASUREMENTS AND MAIN RESULTS

Risk factors and other variables were analyzed with univariate and multivariate analysis. Of the 952 patients studied, 25 (2.6%) had VAP. On univariate analysis, significant risk factors were emergency surgery, chronic obstructive pulmonary disease (COPD), reintubation, coma, steroid treatment, intra-aortic balloon counterpulsation (IABC), enteral feedings, tracheostomy, acute physiology, age, and chronic health evaluation (APACHE II) score, prior antibiotics, and IPPV hours. On multivariate analysis, IPPV hours (153.75 +/- 114.44 v 19.65 +/- 7.99; p < 0.001) and steroids (20% v 0%; p < 0.001) were independent predictors of VAP. The most common pathogens isolated were Pseudomonas aeruginosa (22), Escherichia coli (10), Klebsiella pneumoniae (4), Staphylococcus species (4), and Acinetobacter species (2). The mortality rate in VAP was 16% as compared with 0.2% in non-VAP cases (p < 0.001).

CONCLUSION

These data suggest that by univariate analysis the risk factors for VAP were emergency surgery, COPD, reintubation, coma, steroid treatment, IABC, enteral feedings, tracheostomy, APACHE II score, prior antibiotics, and IPPV hours. On multivariate analysis, only IPPV hours and steroids were independent predictors of VAP. Pseudomonas aeruginosa is the most common pathogen associated with VAP, and the mortality is increased with VAP.

Nosocomial and ventilator-associated pneumonias: developing country perspective

Nosocomial pneumonias are recognized as an important cause of morbidity and mortality in industrialized nations. Emerging data show that they play a similar role in the developing world. A host of extrinsic and intrinsic factors predispose individuals to the development of pneumonias, and a modification of some of these factors provides a low cost solution to prevention of pneumonias. The ideal modality for microbiologic diagnosis of pneumonia remains to be determined. Recent data suggest that there is no difference in outcome when noninvasive techniques are compared with invasive techniques. Antimicrobial resistance is a rapidly increasing problem globally, and combating this with appropriate antibiotic policies, close surveillance, and physician education is essential.