Nosocomial lower respiratory tract infections

Joshi M, Bernstein J, Solomkin J, Wester BA, Kuye O. Piperacillin/tazobactam plus tobramycin versus ceftazidime plus tobramycin for the treatment of patients with nosocomial lower respiratory tract infection. Piperacillin/ Tazobactam Nosocomial Pneumonia Study Group. J Antimicrob Chemother 1999 43(3) 389-97. 

Peloquin CA, Cumbo TJ, Nix DE, et al. Evaluation of intravenous ciprofloxacin in patients with nosocomial lower respiratory tract infections. Arch Intern Med 1989 149 2269-2273. 

Nosocomial lower respiratory tract infections (LRI) represent a significant concern to those caring for hospitalized infants and children because of both their frequency and their potential severity. Pneumonia is the second most common nosocomial infections in all patients hospitalized in the United States regardless of age (1,2). Data from the National Nosocomial Infections Surveillance (NNIS) System documents that nosocomial pneumonia is the second most frequent hospital-acquired infection in critically ill infants and children as well (2,3). Many of the significant risk factors for the development of nosocomial pneumonia previously identified in adult patients, such as severe underlying cardiopulmonary disease, immunosuppression, depressed sensorium, and prior thoracoabdominal surgery, are present in pediatric patients and place them similarly at risk for nosocomial lower respiratory tract infections. In addition, there are specific clinical situations that are unique for neonatal and pediatric patients that provide additional risks for severe nosocomial lower respiratory tract infections (Table 1). 

Although less information is available concerning the actual frequency and risk factors for nosocomial lower respiratory tract infection in children as compared to adults, there is adequate documentation of its importance, particularly for patients hospitalized within intensive care settings (3-7). Nosoco-... 

Nosocomial lower respiratory tract infections may occur in children hospitalized in any area of a hospital. However, the children at greatest risk for nosocomial pneumonia and tracheitis are those cared for in an intensive care setting these account for >50% of all nosocomial pneumonias (28). Nosocomial lower respiratory tract infection will develop in approximately 2% to 10% of children in a pediatric intensive care unit. Similar but slightly lower proportions apply in infants cared for in neonatal intensive care units. 

Table 3 Criteria Used by the National Nosocomial Infections Surveillance System to Define Nosocomial Lower Respiratory Tract Infection Without Pneumonia...

Colinearity between factors prevented some obvious risk factors such as mechanically assisted ventilation and intubation from reaching statistical significance. The close association between many risk factors would likely impact any evaluation of risk for development of nosocomial lower respiratory tract infections in children because multiple simultaneous interventions and therapies would be similar in critically ill children. Also, the small number of patients in this study did not allow for identification of specific underlying diagnosis as risk factors (e.g. severe burns, polytrauma). 

Most bacterial nosocomial lower respiratory tract infections occur by aspiration of bacteria that colonize the oropharynx or upper gastrointestinal tract of the child. Both intubation and mechanical ventilation alter or circumvent some of the patient s natural barrier defenses against infection. These interventions allow organisms from the oropharyngeal or upper gastrointestinal tract greater access to the lower respiratory tract. The aspiration of contaminated materials may be obvious or, more commonly, it is subclinical. The normal respiratory flora of children admitted to a hospital consists of both gram-positive and... 

Laboratory tests documenting the presence of inflammation and pathogenic microorganisms in lower respiratory tract secretions may assist the clinician in establishing the presence of a nosocomial lower respiratory tract infection. However, the isolation of a bacteria or virus from respiratory secretions does not by itself necessarily establish a causal relationship. 

Lower respiratory tract infections IV 400 mg ql2h for 7-14 days. PO 500mgql2hfor 7-14 days (750 mgql2h for 7-14 days for severe or complicated infections). Nosocomial pneumonia IV 400 mg q8h for 10-14 days. 

Respiratory syncytial virus (RSV) is a highly contagious virus that causes lower respiratory tract infection in young children and infants each winter or spring and is a common cause of nosocomial infection on pediatric units (2,178). In recent years, adults who are immunocompromised, elderly, or with chronic obstructive pulmonary disease have also been shown to be at risk for severe RSV infection. 

Lower respiratory tract infections comprise 6% to 27% of all nosocomial infections detected in a pediatric intensive care setting (3,4,26). The actual frequency of nosocomial pneumonia and tracheitis occurring in hospitalized children varies considerably because of marked differences in patient populations... 

Because of the difficulty in accurately establishing the diagnosis of a hospital-acquired pneumonia or tracheitis in a critically ill child, a standardized approach for defining these infections offers the best opportunity for interhospital comparisons. The Centers for Disease Control and Prevention (CDC) definitions for lower respiratory tract infections in children are included in Tables 2 and 3 (27). However, pneumonia and tracheitis may still be diagnosed and treated in children who do not satisfy these criteria. Also, children who fulfill these criteria may not truly have a nosocomial LRI. This occurs most commonly when the child exhibits a deterioration in his or her underlying pulmonary condition. 

Ciprofloxacin is a fluoroquinolone antibiotic that interferes with microbial DNA synthesis. It is indicated in the treatment of infections of the lower respiratory tract, skin and skin structure, bones and joints, urinary tract gonorrhea, chancroid, and infectious diarrhea caused by susceptible strains of specific organisms typhoid fever uncomplicated cervical and urethral gonorrhea women with acute uncomplicated cystitis acute sinusitis nosocomial pneumonia chronic bacterial prostatitis complicated intra-abdominal infections reduction of incidence or progression of inhalational anthrax following exposure to aerosolized Bacillus anthracis. Cipro IV Used for empirical therapy for febrile neutropenic patients. 

The structural configuration of the nasal and oral passageways markedly restrict the access of large particles to the lower respiratory tract. Under normal circumstances, the filtration system of the upper airway and the mucociliary clearance system of the larger airways protect the lower respiratory infection from bacteria that may be present in the patient s environment or that reside in the upper respiratory tract. Nosocomial pneumonia and tracheitis may occur when the mucociliary and cellular defense mechanisms of the lower respiratory tract are evaded. 

The mechanisms responsible for postoperative pneumonia are similar to the etiologies of other types of nosocomial pneumonia. The most frequent mechanism for bacteria to enter the lower respiratory tract is via aspiration of contaminated oropharyngeal or gastric fluids. Less commonly, organisms can be transmitted via contaminated anesthesia or respiratory therapy equipment or may spread hematogenously from a distant site of infection. As described later, both general anesthesia and postoperative alterations in pulmonary mechanics may increase the likelihood of infection after bacterial contamination of the lower respiratory tract. 

Imipenem-cilastatin is effective for a wide variety of infections, including urinary tract and lower respiratory infections intra-abdominal and gynecological infections and skin, soft tissue, bone, and joint infections. The drug combination appears to be especially useful for the treatment of infections caused by cephalosporin-resistant nosocomial bacteria, such as Citrobacter freundii and Enterobacter spp. It would be prudent to use imipenem for empirical treatment of serious infections in hospitalized patients who have recently received other P-lactam antibiotics because of the increased risk of infection with cephalosporin- and/or penicillin-resistant bacteria. Imipenem should not be used as monotherapy for infections owing to P. aeruginosa because of the risk of resistance developing during therapy. 

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