Prevention of nosocomial bacterial pneumonia

Oral microbiome and health

The oral microbiome is diverse in its composition due to continuous contact of oral cavity with the external environment. Temperatures, diet, pH, feeding habits are important factors that contribute in the establishment of oral microbiome. Both culture dependent and culture independent approaches have been employed in the analysis of oral microbiome. Gene-based methods like PCR amplification techniques, random amplicon cloning, PCR-RELP, T-RELP, DGGE and DNA microarray analysis have been applied to increase oral microbiome related knowledge. Studies revealed that microbes from the phyla Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, Fusobacteria, Neisseria, TM7 predominately inhabits the oral cavity. Culture-independent molecular techniques revealed the presence of genera Megasphaera, Parvimonas and Desulfobulbus in periodontal disease. Bacteria, fungi and protozoa colonize themselves on various surfaces in oral cavity. Microbial biofilms are formed on the buccal mucosa, dorsum of the tongue, tooth surfaces and gingival sulcus. Various studies demonstrate relationship between unbalanced microflora and development of diseases like tooth caries, periodontal diseases, type 2 diabetes, circulatory system related diseases etc. Transcriptome-based remodelling of microbial metabolism in health and disease associated states has been well reported. Human diets and habitat can trigger virus activation and influence phage members of oral microbiome. As it is said, “Mouth, is the gateway to the total body wellness, thus oral microbiome influences overall health of an individual”.

Non-Intensive Care Unit Acquired Pneumonia: A New Clinical Entity?

Hospital-acquired pneumonia (HAP) is a frequent cause of nosocomial infections, responsible for great morbidity and mortality worldwide. The majority of studies on HAP have been conducted in patients hospitalized in the intensive care unit (ICU), as mechanical ventilation represents a major risk factor for nosocomial pneumonia and specifically for ventilator-associated pneumonia. However, epidemiological data seem to be different between patients acquiring HAP in the ICU vs. general wards, suggesting the importance of identifying non ICU-acquired pneumonia (NIAP) as a clinical distinct entity in terms of both etiology and management. Early detection of NIAP, along with an individualized management, is needed to reduce antibiotic use and side effects, bacterial resistance and mortality. The present article reviews the pathophysiology, diagnosis, treatment and prevention of NIAP.

Risk factors and clinical characteristics of Stenotrophomonas maltophilia infections in neonates

BACKGROUND

The aim of this study was to review the risk factors and clinical, bacteriological, and epidemiological characteristics of Stenotrophomonas maltophilia infections in our neonatal intensive care unit.

METHODS

A retrospective matched case-control study was performed by comparing 23 cases of S maltophilia with 45 controls to identify the potential risk factors. To identify the case patients, the admission and medical records of patients in the neonatal intensive care unit and records from the Microbiology Department were reviewed between 2003 and 2008.

RESULTS

Sepsis in two neonates (9%), conjunctivitis in two neonates (9%), and ventilator-associated pneumonia in 19 (82%) neonates were determined. Invasive-procedures, exposure to aminoglycoside and carbapenem, total parenteral nutrition, histamine 2 blockers, exposure to steroids, cholestasis, and duration of hospitalization were significantly associated with S maltophilia infections (p<0.05). On multivariate analysis, invasive procedures (odds ratio, 18.81) and duration of hospitalization (odds ratio, 1.06) were determined to be the risk factors for S maltophilia infection. The most active antimicrobial agent was trimethoprim/sulfamethoxazole (87%) for S maltophilia infection, and the mortality rate was 17%.

CONCLUSIONS

Neonatologists should avoid from unnecessary invasive procedures and broad-spectrum antibiotics to reduce S maltophilia infections. Invasive procedures should be finished in the shortest time possible. Agent/factor-specific antibacterial treatment should be administered. Patients being discharged as early as possible will also reduce infection frequency. Stenotrophomonas maltophilia should be considered in patients with high Stenotrophomonas infection risk factors.

Reduction in the incidence of poststroke nosocomial pneumonia by using the "turn-mob" program

BACKGROUND

One of the most common complications in patients with acute ischemic stroke (AIS) is pneumonia, a complication that has an impact on the patient's survival. The purpose of this study was to establish whether the implementation of a passive turning and mobilization program can prevent the occurrence of nosocomial pneumonia (NP) in patients with AIS.

METHODS

We conducted a randomized clinical trial. Patients diagnosed with AIS within the last 48 hours and without mechanical ventilation were included. Group A was the "turn-mob" program: turning and passive mobilization carried out by a previously trained relative. Group B was the control group: standard treatment characterized by turning carried out by the nursing staff. The purpose was to demonstrate whether the implementation of a manual turning and passive mobilization program could reduce the incidence of NP in patients with AIS during their stay at the hospital and up to 14 days after discharge.

RESULTS

In all, 223 patients were included (group A, n = 111; group B, n = 112). Fourteen (12.6%) patients in group A and 30 (26.8%) in group B developed NP. The implementation of the turn-mob program was associated with a decrease in NP, with a relative risk of 0.39 (95% confidence interval .19-.79; P = .008).

CONCLUSION

The turn-mob program applied on patients during the acute phase of an ischemic stroke decreases the incidence of NP.

Association between proton pump inhibitors and respiratory infections: a systematic review and meta-analysis of clinical trials

BACKGROUND

Proton pump inhibitors (PPIs) have become the mainstay of treatment for and prevention of many serious gastrointestinal diseases. Laboratory and clinical evidence suggests that the increase in gastric pH caused by PPIs may be linked to increased bacterial colonization of the stomach and may predispose patients to an increased risk for respiratory infections.

OBJECTIVE

To examine the association between PPI treatment and respiratory infections.

METHODS

A literature search was conducted using PubMed, MEDLINE and Cochrane databases of randomized, placebo-controlled trials evaluating the efficacy of PPIs. Studies that listed and quantified the specific adverse events of 'respiratory infection' or 'upper respiratory infection' (or equivalent), and compared their rates between PPIs and placebo were included. The chi(2) analysis was used to calculate the significance of association in individual studies and a meta-analysis of the selected studies was performed.

RESULTS

Of 7457 studies initially identified and 70 relevant randomized, controlled trials (RCTs) selected, seven studies met the inclusion criteria. A total of 16 comparisons for chi(2) analysis were possible given the multiple dosage arms used in several studies. PPIs included in the studies were esomeprazole, rabeprazole, pantoprazole and omeprazole. More than one-half of the studies showed a trend toward an association between PPI use and respiratory infections, although the majority of the studies failed to show a significant correlation. A single study using high-dose esomeprazole (40 mg) showed a significant association -4.3% rate of respiratory infections in the active group compared with 0% in the placebo group (P<0.05). Meta-analysis showed a trend toward an association between PPIs and respiratory infections, although it failed to reach significance (OR 1.42, 95% CI 0.86 to 2.35; P=0.17).

CONCLUSION

Although a trend was evident in both a chi(2) analysis of individual studies and a meta-analysis, the present review and meta-analysis failed to show a conclusive association between PPIs and respiratory infections. Very few RCTs actively sought out respiratory infections, which excluded the majority of RCTs identified. A well-structured, placebo-controlled prospective study would be needed to determine whether a true association between PPIs and respiratory infections exists.

[Duration of antibiotic therapy for ventilator-associated pneumonia: comparison of 7 and 10 days. A pilot study]

OBJECTIVE

To compare the efficiency of a 7-day antibiotics regimen with a 10-day regimen for ventilator-associated pneumonia (VAP).

STUDY DESIGN

Prospective randomized study.

PATIENTS AND METHODS

Adults patients ventilated for more than 48 hours in the intensive care unit (ICU) with a clinical diagnosis of VAP documented by positive quantitative cultures of tracheal aspiration were included in this study. All included patients were randomized in two groups. Ten-day group: 10 days antibiotic therapy, and 7-day group: 7 days antibiotic therapy. Primary judgment criteria were 14- and 28-day mortality, the number of days without antibiotics. Secondary judgments criteria were rate of recurrent pulmonary infection, the evolution of the clinical pulmonary infection scores (CPIS), the length of ICU stay and the length of mechanical ventilation.

RESULTS

Thirty patients were included in this study (16 in the 10-day group and 14 in the 7-day group). The demographic and clinical characteristics of the groups assigned to receive antibiotic therapy for 7 or 10 days were generally similar. The 14-day and 28-day mortality rate following VAP onset were 31.2 and 37.5% in the 10-day group and 7.1 and 35.7% in the 7-day group. The difference was not significant. The number of day without antibiotics and without mechanical ventilation turned out: 1.75 and 2.06 days versus 4.14 and 3.43 days in the 10-day group and 7-day group respectively, the recurrent rate of pulmonary infection (12.5% versus 14.3%, p=0.6), the length of stay in the ICU (27.7 days versus 26.0 days, p=0.8) and the evolution of the CPIS were no different in the two groups.

CONCLUSION

In patients with microbiologically confirmed VAP who received appropriate empirical antibiotic therapy, a 7-day antibiotic regimen was as efficient clinically and microbiologically as a 10-day antibiotic regimen with a reduction of antibiotic use.

Ventilator-associated pneumonia using a closed versus an open tracheal suction system

OBJECTIVE

The aim of this study was to analyze the prevalence of ventilator-associated pneumonia (VAP) using a closed-tracheal suction system vs. an open system.

DESIGN

Prospective and randomized study, from October 1, 2002, to December 31, 2003.

SETTING

A 24-bed medical-surgical intensive care unit in a 650-bed tertiary hospital.

PATIENTS

Patients requiring mechanical ventilation for >24 hrs.

INTERVENTIONS

Patients were randomized into two groups; one group was suctioned with the closed-tracheal suctioning system and another group with the open system.

MEASUREMENTS

Throat swabs were taken at admission and twice a week until discharge to classify pneumonia in endogenous and exogenous.

MAIN RESULTS

A total of 443 patients (210 with closed-tracheal suction system and 233 with the open system) were included. There were no significant differences between groups of patients in age, sex, diagnosis groups, mortality, number of aspirations per day, and Acute Physiology and Chronic Health Evaluation II score. No significant differences were found in either the percentage of patients who developed VAP (20.47% vs. 18.02%) or in the number of VAP cases per 1000 mechanical ventilation-days (17.59 vs. 15.84). There were also no differences in the VAP incidence by mechanical ventilation duration. At the same time, we did not find any differences in the incidence of exogenous VAP. Likewise, there were also no differences in the microorganisms responsible for pneumonia. Patient cost per day for the closed suction was more expensive than the open suction system (11.11 US dollars +/- 2.25 US dollars vs. 2.50 US dollars +/- 1.12 US dollars, p < .001).

CONCLUSION

We conclude that in our study, the closed-tracheal suction system did not reduce VAP incidence, even for exogenous pneumonia.

Ventilator-associated pneumonia

Ventilator-associated pneumonia is the most common nosocomial infection. Mortality rates, morbidity, and costs are all increased in the patient with VAP, and every measure should thus be taken to prevent its development. There are several clearly defined risk factors for VAP, and awareness of these can facilitate early diagnosis and hence treatment. In this article, we discuss the risk factors, strategies for prevention, approaches to diagnosis and management plan for the patient with VAP.

Costs and risk factors for ventilator-associated pneumonia in a Turkish university hospital's intensive care unit: a case-control study

Background

Ventilator-associated pneumonia (VAP) which is an important part of all nosocomial infections in intensive care unit (ICU) is a serious illness with substantial morbidity and mortality, and increases costs of hospital care. We aimed to evaluate costs and risk factors for VAP in adult ICU.

Methods

This is a-three year retrospective case-control study. The data were collected between 01 January 2000 and 31 December 2002. During the study period, 132 patients were diagnosed as nosocomial pneumonia of 731 adult medical-surgical ICU patients. Of these only 37 VAP patients were assessed, and multiple nosocomially infected patients were excluded from the study. Sixty non-infected ICU patients were chosen as control patients.

Results

Median length of stay in ICU in patients with VAP and without were 8.0 (IQR: 6.5) and 2.5 (IQR: 2.0) days respectively (P < 0.0001). Respiratory failure (OR, 11.8; 95%, CI, 2.2–62.5; P < 0.004), coma in admission (Glasgow coma scale < 9) (OR, 17.2; 95% CI, 2.7–107.7; P < 0.002), depressed consciousness (OR, 8.8; 95% CI, 2.9–62.5; P < 0.02), enteral feeding (OR, 5.3; 95% CI, 1.0–27.3; P = 0.044) and length of stay (OR, 1.3; 95% CI, 1.0–1.7; P < 0.04) were found as important risk factors. Most commonly isolated microorganism was methicillin resistant Staphylococcus aureus (30.4%). Mortality rates were higher in patients with VAP (70.3%) than the control patients (35.5%) (P < 0.003). Mean cost of patients with and without VAP were 2832.2+/-1329.0 and 868.5+/-428.0 US Dollars respectively (P < 0.0001).

Conclusion

Respiratory failure, coma, depressed consciousness, enteral feeding and length of stay are independent risk factors for developing VAP. The cost of VAP is approximately five-fold higher than non-infected patients.

All great truths are iconoclastic: selective decontamination of the digestive tract moves from heresy to level 1 truth

OBJECTIVE

The objective was to compare evidence of the effectiveness, costs and safety of the traditional parenteral antibiotic-only approach against that gathered from 53 randomised trials involving more than 8,500 patients and six meta-analyses on selective decontamination of the digestive tract (SDD) to control infection on the intensive care unit (ICU). PHILOSOPHY: Traditionalists believe that all infections are due to breaches of hygiene except those established in the first 2 days, and that all micro-organisms can cause death. In contrast, newer insights show that transmission via the hands of carers are responsible only for infections occurring after one week, and that only a limited range of 15 potential pathogens contribute to mortality. INTERVENTIONS TO PREVENT ICU INFECTION: The traditional approach is based on hand disinfection aiming at the prevention of transmission of all micro-organisms, to control all infections that occur after 2 days on the ICU. The second feature is the restrictive use of systemic antibiotics, only in cases of microbiologically proven infection. In contrast, SDD aims to control the three types of infection: primary, secondary endogenous and exogenous due to 15 potential pathogens. The classical SDD tetralogy comprises four components: (i) a parenteral antibiotic, cefotaxime, administered for three days to prevent primary endogenous infections typically occurring "early"; (ii) the oropharyngeal and enteral antimicrobials, polymyxin E, tobramycin and amphotericin B administered in throat and gut throughout the treatment on the ICU to prevent secondary endogenous infections tending to develop "late"; (iii) a high standard of hygiene to control transmission of potential pathogens; and (iv) surveillance samples of throat and rectum to monitor the efficacy of the treatment.

ENDPOINTS

(i) Infectious morbidity; (ii) mortality; (iii) antimicrobial resistance; and (iv) costs.

RESULTS

Properly designed trials on hand disinfection have never demonstrated a reduction in either pneumonia and septicaemia, or mortality. Two randomised trials using restrictive antibiotic policies failed to show a survival benefit at 28 days. In both trials the proportion of resistant isolates obtained from the lower ways was >60% despite significantly less use of antibiotics in the test group. A formal cost effectiveness analysis of the traditional antibiotic policies has not been performed. On the other hand, two meta-analyses have shown that SDD reduces the odds ratio for lower airway infections to 0.35 (0.29-0.41) and mortality to 0.80 (0.69-0.93), with a 6% overall mortality reduction from 30% to 24%. No increase in the rate of super infections due to resistant bacteria could be demonstrated over a period of 20 years of clinical research. Four randomised trials found the cost per survivor to be substantially lower in patients receiving SDD than for those traditionally managed.

CONCLUSIONS

The traditionalists still rely on level 5 evidence, i.e. expert opinion, with a grade E recommendation, whilst the proponents of SDD are able to cite level 1 evidence allowing a grade A recommendation in their attempts to control infection on the ICU. The main reason for SDD not being widely used is the primacy of opinion over evidence.

Pharmaceutical strategies to prevent ventilator-associated pneumonia

The increasing incidence of hospital-acquired (nosocomial) infection is a disturbing phenomenon resulting in significant patient mortality and putting considerable strain on healthcare budgets and personnel. One particularly serious aspect of nosocomial infection is that of ventilator-associated pneumonia (VAP). This arises in patients who receive mechanical ventilation within the intensive care unit. The quoted incidence of VAP varies widely (5-67%) and the reported mortality of patients with VAP is in the range of 24-71%. This review will examine the many factors that account for these wide ranges reported, including the patient population under investigation, the causative organism, the method of diagnosis, interventions employed and preventative strategies. The use of bioactive and drug-impregnated biomaterials for endotracheal tube construction is discussed as novel approaches to the prevention of VAP.

Pulmonary infiltrates in patients receiving long-term glucocorticoid treatment: etiology, prognostic factors, and associated inflammatory response

BACKGROUND

Glucocorticoid treatment alters immunoregulatory defense mechanisms and may therefore favor the development of different pulmonary infections.

METHODS

The etiology, prognostic factors, and associated inflammatory response of pulmonary infiltrates in 33 patients receiving long-term glucocorticoid treatment (LTGCT) were prospectively evaluated.

RESULTS

Aspergillus spp (n = 9, 31%) and Staphylococcus spp (n = 6, 21%) were the most common causative agents. Using different diagnostic techniques, we obtained a specific diagnosis in 28 of 33 episodes (85%) of pulmonary infiltrates. Bronchoscopic techniques provided the diagnosis in 64% of the cases. Crude mortality was 45%. Variables associated with mortality were as follows: age > 64 years, bilateral radiographic involvement, delay in diagnosis, inappropriate empirical treatment, Simplified Acute Physiology Score (SAPS) II > or = 25, and requirement for mechanical ventilation (MV). SAPS II > or = 25 (odds ratio [OR], 16; 95% confidence interval, 1 to 260) and MV requirement (OR, 50; 95% confidence interval, 2 to 360) were also significant on multivariate analysis. Pulmonary infections were associated with an increase in the concentration of relevant inflammatory cytokines such as tumor necrosis factor-alpha and interleukin-6 both in serum and BAL. This local and systemic inflammatory response was attenuated when compared with the response observed in patients with pulmonary infections but without glucocorticoid treatment or receiving glucocorticoids for a short period of time (< 9 days).

CONCLUSIONS

Pulmonary infiltrates in patients receiving LTGCT are often caused by fungi and Gram-positive cocci, and are associated with attenuated local and systemic inflammatory response. Although in most cases, sputum cultures and bronchoscopic techniques are diagnostic, the associated mortality is high, particularly in those requiring MV.

Nosocomial pneumonia in pediatric patients: practical problems and rational solutions

Nosocomial pneumonia is a common hospital-acquired infection in children, and is often fatal. Risk factors for nosocomial pneumonia include admission to an intensive care unit, intubation, burns, surgery, and underlying chronic illness. Viruses, predominantly respiratory syncytial virus (RSV), are the most common cause of pediatric nosocomial respiratory tract infections. Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) are the predominant bacterial pathogens, and are associated with a high mortality rate. Staphylococcus aureus and Staphylococcus epidermidis are the most common Gram-positive bacteria causing nosocomial pneumonia; infections with these organisms have a better outcome than those with Gram-negative organisms. An increasing problem is the emergence of multiresistant Gram-positive and Gram-negative nosocomial pathogens. Distinguishing nosocomial pneumonia from other pulmonary processes may be difficult; diagnosis is based on clinical signs, radiological findings, and microbiological results. Recommended empiric therapy should consider factors such as the time of onset of illness, severity of disease, and specific risk factors for nosocomial pneumonia, including use of mechanical ventilation, underlying disease, or recent use of antibacterials. The resident local hospital flora should be considered when selecting therapy for nosocomial pneumonia. Early initiation of appropriate empiric therapy reduces morbidity and mortality. For empiric treatment of bacterial nosocomial pneumonia, an intravenous antibacterial regimen that includes coverage of Gram-negative bacilli and Gram-positive organisms should be used. A carbapenem or ureidopenicillin derivative (piperacillin) plus a beta-lactamase inhibitor should be used where extended spectrum beta-lactamase-producing Enterobacteriaceae are endemic. Therapy should be modified when a specific pathogen and its antimicrobial susceptibility are identified. Effective prevention of nosocomial pneumonia requires infection control measures that affect the environment, personnel, and patients. Of these, hand hygiene, appropriate infection control policies, and judicious use of antibacterials are essential.

Infection in the chronically critically ill: unique risk profile in a newly defined population

Although CCI is defined as prolonged ventilatory failure with tracheotomy stemming from preceding critical illness, the contention that multisystem debilities impact on most CCI patients' care and recovery is a central thesis of this volume. Perhaps reflecting the combined debilities inherent in CCI, infectious complications take their toll in morbidity, mortality, and persistent ventilatory insufficiency. Enhanced susceptibility to infection results from a potent admixture of barrier breakdown, exposure to virulent and resistant nosocomial pathogens, and postulated "immune exhaustion" that stems from the combined impact of comorbidities and the sequellae of critical illness. Strategies to improve outcome in CCI-related infection include standard measures of support especially nutrition, reducing environmental inoculum through pulmonary hygiene measures, skin care, and limiting barrier breaches, and appropriate antimicrobials directed at likely pathogens. Future stratification of patient risk on the basis of immune phenotype or genotype and potential immunomodulatory prophylaxis may be around the corner, as new prospects in the pharmaceutical armamentarium are presently undergoing testing.

Emergence of multi-drug-resistant Acinetobacter anitratus species in neonatal and paediatric intensive care units in a developing country: concern about antimicrobial policies

Antimicrobial abuse is a serious risk factor for the emergence of multi-drug-resistant (MDR) pathogens. We report on the emergence of multi-drug-resistant Acinetobacter anitratus species over two 8-week periods in 1999 in the neonatal and paediatric intensive care units (NICU and PICU) of King Edward VII Hospital, Durban, South Africa. The source, transmission dynamics, microbiological evaluations, antibiotic utilization patterns and outcome were evaluated. MDR Acinetobacter anitratus was isolated from different body sites in 23 infants less than 2 months of age, 18 in the PICU and five in the NICU. The mortality was 56.5% and two survivors required re-admission. Ten of the 23 cases had entered the ICU with MDR Acinetobacter anitratus. Eleven of the study infants had received broad-spectrum antimicrobial agents before entering the ICU, while all infants with nosocomially acquired MDR Acinetobacter anitratus had received broad-spectrum antimicrobial agents. All the surgical cases with MDR Acinetobacter anitratus died. Microbiological data from both ICUs for 1999 indicated that gram-negative bacteria accounted for two-thirds of isolates, Acinetobacter anitratus and Klebsiella pneumoniae accounting for 33% and 27% of the isolates, respectively. Only 53% and 57% of all Acinetobacter spp isolates were susceptible to piperacillin/tazobactam and carbepenems, respectively. MDR Acinetobacter anitratus is an emerging problem to which antimicrobial abuse contributes.

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

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

Nosocomial pneumonia: epidemiology, pathogenesis, diagnosis, treatment and prevention

Nosocomial pneumonia is the second most common nosocomial infection and the leading cause of death from hospital-acquired infection. Supine body position in mechanically ventilated patients, and cardiopulmonary resuscitation and continuous sedation are significant risk factors for developing nosocomial pneumonia. During the past 2 years some new therapeutic approaches for nosocomial pneumonia and modifications to established therapies have been described, such as optimal pharmacodynamic evaluations, monotherapy versus combination therapy, computer-assisted management programmes and antibiotic rotations.