Respiratory infection complicating long-term tracheostomy. The implication of persistent gram-negative tracheobronchial colonization

Colonization of the lower respiratory tract by enteric Gram-negative bacilli (EGNB) has been a frequent finding in patients with long-term tracheostomies; however, the association of hospitalization and certain features of serious illness with this phenomenon has not been clearly established. Because such factors can render the oropharynx more susceptible to EGNB colonization, we sought to discover whether they can also have this effect on the tracheobronchial tree and its microflora. Thus, we collected serial paired culture samples from these two mucosal sites in 15 subjects with long-term tracheostomies and examined patterns and rates of colonization and related these findings to clinical parameters. In 49 sets of cultures, we found that EGNB (especially Pseudomonas species) were present in significantly fewer upper-airway cultures (36.7 percent) than lower-airway cultures (75.5 percent) (p = 0.009). At the tracheobronchial site, seven subjects had persistent EGNB colonization, all with Pseudomonas species, while only one subject had this finding at the oropharyngeal site (p = 0.015). Patients with persistent tracheobronchial colonization were more ill than those without this finding. They were treated with higher doses of prednisone (p = 0.06), received antibiotics more often, and developed purulent tracheobronchitis more often (100 percent vs 25 percent) than patients without persistent colonization. In addition, in the month following the culture survey, four subjects developed pneumonia, and three of these had previous persistent tracheobronchial colonization.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intestinal colonization and nosocomial spread of Clostridium difficile in pediatric cancer patients under long-term hospitalization

Clostridium difficile is a major causative agent of antimicrobial-associated diarrhea, and the leading cause of nosocomial diarrhea. We clarified intestinal colonization and nosocomial spread of C. difficile in pediatric cancer patients undergoing antineoplastic therapy during long-term hospitalization. Subjects were 10 children with pediatric malignant diseases admitted from November 2005 to December 2006, aged 5 to 15 years, who received antineoplastic agents. Stool specimens were examined at hospitalization, after each course of treatment with antineoplastic chemotherapy, and when symptoms such as diarrhea or fever occurred. While C. difficile was detected from stool specimens of 8 of 10 children during their hospital stay, 6 of these 8 children were negative for C. difficile on the day of their admission. These results demonstrate that the use of antimicrobial agents and antineoplastic agents lead to overgrowth of C. difficile in intestinal tract of pediatric cancer patients. Five of the 8 children carried toxin A-positive, toxin B-positive C. difficle and 2 were diagnosed with C. difficile-associated diarrhea (CDAD). This demonstrates that CDAD is not a rare infection in pediatric cancer patients. Nine C. difficile isolates from 8 children were analyzed by PCR ribotyping. Two isolates from 2 children were typed into the same type;banding patterns of the remaining 7 isolates from 6 children were unique.     

Bacterial community-acquired pneumonia in older patients

Pneumonia in the elderly remains a major source of morbidity and mortality in an age group that is growing in numbers. It remains unclear whether the propensity of older adults to develop community-acquired pneumonia represents an aging of host defenses, secondary effects of comorbid disease, or both. The signs and symptoms of pneumonia in the elderly are more subtle than in younger populations, which may lead to a delay in diagnosis. Although therapy for community-acquired pneumonia in the elderly is the same as for younger populations, mortality is higher, leading to an important role for prevention.     

Respiratory infection in the chronically critically ill patient. Ventilator-associated pneumonia and tracheobronchitis

The long-term ventilated patient is at high risk for developing nosocomial pneumonia or tracheobronchitis. In general, the frequency of infection increases with the duration of mechanical ventilation, but the risk appears to be greatest in the first week of intubation. Although these types of infection are common and may have morbidity and mortality impact, the daily risk is less in the long-term ventilated patient than in the acutely ill intubated patient. This reduced daily risk may reflect a "survivor effect," with less healthy patients dying early in the hospital stay and not surviving long enough to undergo tracheostomy and long-term ventilation. A number of factors predispose these patients to infection, including host defense impairment and exposure to large numbers of bacteria. This exposure can occur through the airway, and proper care of respiratory therapy devices is essential to minimize the risk for infection. Most infections of the lower respiratory tract are preceded by airway colonization with EGN bacteria and, with improvement in host defenses and nutrition, infection in the face of colonization is less likely. In some patients, colonization can be eliminated. When the long-term ventilated patient does develop infection, it generally involves highly resistant gram-negative or gram-positive organisms and therapy should be prompt and appropriate. Not all such patients respond to systemic antibiotics, and the use of adjunctive aerosol therapy may have benefit for those with either tracheobronchitis or pneumonia, especially if highly resistant pathogens are present.     

Bacterial colonization, probiotics, and necrotizing enterocolitis

The intestinal microflora has a significant role in intestinal health and gut function. The neonatal population is unique in that intestinal colonization is not established and is known to be influenced by delivery method, feeding, gestational age, and medical interventions. The preterm infant is particularly sensitive to colonization patterns as inherent intestinal defense mechanisms are immature and immature intestinal epithelial cells are known to have exaggerated inflammatory responses to both commensal and pathogenic bacteria. These responses contribute to the development of neonatal necrotizing enterocolitis in this patient population. As certain bacteria are known to influence intestinal maturation and down-regulate intestinal inflammation, it has been suggested that influencing the intestinal flora of preterm infants may be beneficial. Clinical studies indicate that probiotic therapy may decrease the incidence of necrotizing enterocolitis and studies are ongoing to elucidate the mechanism of action of different probiotic organisms. Although concerns remain and further study is necessary, probiotics are a plausible means of optimizing intestinal colonization and influencing outcome of these vulnerable infants.     

Percutaneous dilatational tracheostomy. Results and long-term follow-up.

Ciaglia et al first reported percutaneous dilatational subcricoid tracheostomy in 1985. We are now reporting the results on 165 patients with follow-up on 52 patients who went on to decannulation. Our technique has been slightly modified and these points are emphasized. To date, there have been no significant perioperative or postoperative complications and no long-term complications on 52 patients who were followed clinically, postdecannulation, for from four months to five years. The procedure is recommended as simple, safe, and cost-effective. We feel it is the technique of choice for routine elective tracheostomy.     

Nosocomial tracheobronchitis in mechanically ventilated patients: incidence, aetiology and outcome.

The aim of this study was to determine the incidence, the organisms responsible for and the impact on outcome of nosocomial tracheobronchitis (NTB) in the intensive care unit (ICU). This prospective observational cohort study was conducted in a 30-bed medical/surgical ICU over a period of 6.5 yrs. All patients ventilated for >48 h were eligible. Patients with nosocomial pneumonia (NP) without prior NTB were excluded. Patients with first episodes of NTB were compared with those without NTB by univariate analysis. The study diagnosed 201 (10.6%) cases of NTB. Pseudomonas aeruginosa was the most common bacteria. NP rates were similar in patients with NTB compared with patients without NTB. Even in the absence of subsequent NP, NTB was associated with a significantly higher length of ICU stay and duration of mechanical ventilation in both surgical and medical populations. Mortality rates were similar in NTB patients without subsequent NP compared with patients without NTB. Antimicrobial treatment in NTB patients was associated with a trend to a better outcome. Nosocomial tracheobronchitis is common in mechanically ventilated intensive care unit patients. In this population, nosocomial tracheobronchitis was associated with longer durations of intensive care unit stay and mechanical ventilation. Further studies are needed to determine the impact of antibiotics on outcomes of patients with nosocomial tracheobronchitis.     

Thyroid dysfunction following bone marrow transplantation: long-term follow-up of 80 pediatric patients

Thyroid function was evaluated in children surviving disease-free for 2 years or more following bone marrow transplantation (BMT) for severe aplastic anemia (27 patients), acute non-lymphoblastic leukemia (28 patients), and acute lymphoblastic leukemia (25 patients). Pre-BMT conditioning consisted of high dose chemotherapy and total lymphoid irradiation with 750 cGy for patients with severe aplastic anemia, and for patients with leukemia, high dose chemotherapy and single dose total body irradiation with 750-850 cGy (33 patients) or fractionated total body irradiation with 1320 cGy (20 patients). Compensated hypothyroidism (elevated thyroid stimulating hormone (TSH) with a normal thyroxine index) occurred in 20/80 patients with a median time of onset of 12.3 months post-BMT (range 4-30). No patients developed primary hypothyroidism (elevated thyroid stimulating hormone with low thyroxine index). In seven patients, compensated hypothyroidism was transient with TSH returning to normal at a median of 60 months post-BMT (range 11-75). Six patients with compensated hypothyroidism received thyroid hormone replacement therapy. Time to development of compensated hypothyroidism was associated (p = 0.03) with underlying disease and radiation (11 of 27 patients with severe aplastic anemia + total lymphoid irradiation versus nine of 53 patients with leukemia + total body irradiation). In aplastic anemia patients, but not patients with leukemia, the incidence of thyroid hypofunction 5 years post-transplant was significantly higher (p less than 0.001) in those receiving methotrexate alone (82%) as prophylaxis for graft-versus-host disease compared with those receiving a regimen of methotrexate, antithymocyte globulin and prednisone (16%).     

Bacterial colonization and the development of intestinal defences.

In humans, intestinal defences develop during gestation and, at full term, have the capacity to respond in an appropriate manner to infectious agents and foreign antigens. Before an active protective response can occur, however, the gut must first be exposed to colonizing bacteria. Colonization with diverse intestinal microbes is necessary for the development of important gut defenses such as the synthesis and secretion of polymeric immunoglobulin A and the generation of a balanced T helper (Th) cell response. Insights into normal immune physiological development of the gut have been made by studying the germ-free animal and intestinal defenses. These studies have provided insights into the physiology of immune responses. Two important immunological functions are the secretion of polymeric immunoglobulin A to protect the intestinal surface against harmful stimuli and inhibition of the systemic response to commensal bacteria and food proteins (eg, oral tolerance) to prevent chronic inflammation. Neither function exists in the germ-free state, but rapidly develops after conventionalization (colonization) of the germ-free animal. In the present review, the importance of bacterial colonization on the appearance of normal mucosal immune function and to the clinical consequences of inadequate colonization to the development of disease will be discussed. For example, excessive Th2 activity can lead to atopy, whereas Th1 predominance is found in conditions such as Helicobacter pylori gastritis and Crohn's disease. With the eradication of infectious diseases in developed countries in the past three decades, the incidence of atopic and autoimmune diseases has increased. This epidemiological observation has been explained by the 'hygiene hypothesis', which suggests that a reduction in microbial burden by public health measures has contributed to an immunological imbalance in the intestine. A family of pattern recognition receptors (Toll-like receptors) on gut lymphoid and epithelial cells mediates innate immune responses to bacterial molecular patterns and, thereby, orchestrates acquired immunity. As the role of bacterial communication within the gut (bacterial-epithelial cross-talk) is clarified, physicians should be able to modulate gut immune responses, for example, by the use of probiotics.     

Bacterial colonization and infection in the neonate

The vast majority of healthy term neonates tolerate their abrupt introduction to the bacterial world with little risk of infection. However, infants who require a longer hospital stay are at greater risk of having an infection, particularly when intensive care is needed. In one study, 15.3 percent of the infants in an intensive care unit acquired a nosocomial infection. Gram-negative bacilli have emerged as the principle cause of nosocomial infection. Nosocomial infection due to gram-negative bacilli usually occurs in neonates already colonized with gram-negative bacilli in the pharynx or intestine, and the risk of colonization with hospital strains of gram-negative bacilli (which are often resistant to multiple antibiotics) increases dramatically the longer a baby stays in intensive care. The factors which predispose individual neonates to colonization and infection with gram-negative bacilli require further study, but gram-negative bacilli are most often transmitted among neonates on the hands of personnel. Neonates in whom intestinal colonization with gram-negative bacilli develops are a particularly important reservoir of gram-negative bacilli in the nursery; once colonized, infants may harbour antibiotic-resistant hospital strains of gram-negative bacilli in their stool for more than a year. Pharyngeal colonization with alpha streptococci appears to protect neonates from pharyngeal colonization with gram-negative bacilli, and bacterial interference may play an important role in regulating intestinal colonization as well. Investigation of the mechanisms of bacterial interference may lead to better understanding of the colonization process and development of alternatives to classic infection control methods.     

Bacterial pneumonia in patients with the acquired immunodeficiency syndrome

Eighteen episodes of community-acquired bacterial pneumonia were diagnosed in 13 patients among 336 with the acquired immunodeficiency syndrome (AIDS) cared for at Memorial Sloan-Kettering Cancer Center since 1979. Bacterial pathogens isolated in 16 of 18 episodes were Haemophilus influenzae in 8, Streptococcus pneumoniae in 6, group B streptococcus in 1, and Branhamella catarrhalis in 1. Eight episodes were presumed Pneumocystis carinii pneumonia until cultures obtained at bronchoscopy confirmed a bacterial cause. Specific antibacterial therapy was curative in 16 of 18 episodes; 2 patients died. Given an estimated yearly incidence of pneumococcal pneumonia in the general population of 2.6/1000, 1.09 cases were expected in our patients with AIDS; we saw 6 (p = 0.001), for an attack rate of 17.9/1000. Bacteria associated with B-cell defects should be anticipated when formulating empiric antibiotic therapy, pending a definitive diagnosis, for pulmonary infiltrates in patients with AIDS.     

Bacterial pneumonia in patients with human immunodeficiency virus infection

Human immunodeficiency virus (HIV) infection is associated with abnormalities of humoral immunity that result in an increased incidence of bacterial pneumonia. From 2% to 10% of acquired immunodeficiency syndrome (AIDS)-associated pneumonia is caused by encapsulated bacteria. Clinical features are usually typical of community-acquired pneumonia and include fever, productive cough, and chest pain. Focal radiographic infiltrates, an elevated WBC count, and mild hypoxemia are commonly observed. Streptococcus pneumoniae, Haemophilis influenzae, other Streptococcus species, and Branhamella catarrhalis are the predominant organisms. Bacteremia is frequent, especially with S pneumoniae infections. Despite a rapid response to antibmicrobial agents, many patients experience recurrences. Prevention of bacterial infections with prophylactic antibiotics and immunizations is recommended for selected HIV-infected patients.     

The incidence of bacteremia in pediatric patients following tooth extraction.

Procedures which produce bacteremias may lead to bacterial endocarditis in the susceptible patient. Recent work has suggested that bacteremia does not occur in children following extraction of teeth as it does in adults. One hundred and seven children were divided into four groups. Group I, which consisted of children who had nondiseased primary teeth extracted, had 35% positive blood cultures. Group II consisted of children who had diseased primary and permanent teeth removed. The incidence of positive blood cultures was 53%. Group III, which consisted of patients who had extractions of nondiseased permanent teeth, had a 61% incidence of positive blood cultures. Group IV served as a negative control. Bacteremias do occur in children following the extraction of normal and diseased primary and permanent teeth. Therefore, the susceptible pediatric patient who is to undergo a dental extraction procedure must be given prophylactic antibiotics.     

Sex-based short- and long-term survival in patients following complicated myocardial infarction.

AIMS: Mortality in women following an acute myocardial infarction (AMI) is higher than in men, in that women are older and have more co-morbidity at the time of AMI. We evaluated short- and long-term sex-related differences in management and prognosis among high-risk patients following AMI. METHODS AND RESULTS: A total of 1575 women and 3902 men with AMI and heart failure, left ventricular dysfunction, or anterior Q waves, were recruited for participation in the OPTIMAAL trial and followed for 2.7+/-0.9 years in seven European countries. Symptomatic heart failure was more common in women when compared with men. Women were older, with more hypertension and diabetes mellitus. Fewer women were treated with thrombolytics (P<0.001 in all cases). Women had a 1.37-fold higher risks of death (P<0.001) during follow-up, but no differences were observed after adjusting for age. However, in-hospital mortality was significantly higher in women (4.89 vs. 2.54%; P<0.001) and a 1.57-fold higher risk of in-hospital death (P=0.006) persisted after adjusting for age and co-morbidities. CONCLUSION: Among high-risk patients with AMI, age-adjusted long-term survival was similar between sexes. However, adjusted in-hospital mortality was significantly higher in women. Higher short-term risk may warrant more rapid and appropriate management of women with AMI.     

Predictors of long-term mortality in patients with ventilator-associated pneumonia

Purpose

To determine the long-term outcome of ventilator-associated pneumonia (VAP) and identify factors associated with increased mortality.

Methods

We retrospectively studied 671 patients with VAP admitted to an intensive care unit between 1994 and 2000. We determined long-term and out-of-hospital mortality for these patients.

Results

The in-hospital mortality was 42.3%; 19.8% of patients had concomitant bacteremia, the mortality was 59.7% versus 38.0% for those without bacteremia (P <.001). The factors associated with increased hospital mortality by univariable analysis were: diagnosis on admission, the need of vasopressors during the stay in the intensive care unit, not undergoing a tracheostomy, the absence of fever, the presence of concomitant bacteremia, and renal failure or the need for dialysis. Patients transferred from an outside hospital and patients with normal serum bicarbonate, serum total bilirubin <2 mg/dL, and platelets >120 × 4> 10³/μL had a lower in-hospital mortality. All of these factors except bilirubin level, platelet count, transfer from outside hospital, and serum bicarbonate remained significant on multivariable analysis. The estimated mortality at 1, 3 and 5 years is 25.9% (95% confidence interval [CI], 20.2-30.1%), 33.6% (95% CI, 27.4-39.2%) and 44.7% (95% CI, 38.1-50.6%), respectively.

Conclusions

VAP is associated with a high rate of hospital and long-term mortality. The presence of bacteremia is associated with a high mortality. The 5-year estimated mortality of the survivors is less than 50%.     

Nosocomial pneumonia in elderly patients following cardiac surgery

OBJECTIVE: To identify modifiable risk factors of nosocomial pneumonia (NP) in elderly patients post-cardiac surgery. DESIGN: A case-control study. SETTING: Post-operative intensive care unit of a tertiary-level university affiliated hospital. SUBJECTS: Seventy three case-control pairs. Case patients referred to elderly patients who developed pneumonia post-cardiac surgery. Controls subjects were matched for age, gender, type of surgery, forced expiratory volume in 1s (FEV(1)), and ejection fraction. MEASUREMENTS: Baseline sociodemograpahic information, Charlson Comorbidity Index score, intra- and post-operative data were collected. When suspected, the presence of NP was confirmed by quantitative culture of protected bronchoalveolar lavage fluid 10(3) colony forming unit/ml or positive blood/pleural fluid culture identical to that recovered from respiratory samples. RESULTS: The incidence of NP in elderly post-heart surgery was 8.3%. The mean duration after heart surgery to the occurrence of pneumonia was 7.2+/-4.9 days. Four variables were found to be significantly related to the development of NP by multivariate analysis: Charlson Index >2 (adjusted odds ratio [AOR] 4.7; 95% confidence interval [CI], 1.9-11.4; P<0.001), reintubation (AOR 6.2; 95% CI, 1.1-36.1; P=0.04), transfusion 4 units of PRBC (AOR 2.8; 95% CI, 1.2-6.3; P=0.01), and the mean equivalent daily dose of morphine (AOR 4.6; 95% CI, 1.4-14.6; P=0.01). CONCLUSIONS: Although there are limited effective measures to lessen the burden of comorbidities, avoiding reintubation, finding a substitute to allogenic blood transfusion, and improved assessment of pain management could reduce the rate of NP in the post-operative period of cardiac surgery in the elderly population.