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Biomedical subjects

Louis M Bell

Publications and source records attributed to Louis M Bell.

14 recordsLinked to original sources
PubMed2005

Postoperative mediastinitis in children: epidemiology, microbiology and risk factors for Gram-negative pathogens.

BACKGROUND: Mediastinitis, although an infrequent complication of median sternotomy, represents a significant source of morbidity and mortality. OBJECTIVE: To determine the incidence and describe the epidemiology and microbiology of mediastinitis in children after cardiac surgery and to identify risk factors for the development of Gram-negative mediastinitis. STUDY DESIGN: This was a retrospective case-control study nested within the cohort of children, birth to 18 years of age, undergoing median sternotomy between January 1, 1995 and December 31, 2003. RESULTS: Forty-three cases of mediastinitis were identified. The incidence of mediastinitis was 1.4%. Median patient age at time of inciting sternotomy was 32 days (interquartile range, 5 days-9 months). Twenty-three (54%) cases occurred in girls. Median time to onset of infection after surgery was 11 days (range, 4-34 days). Overall Gram-positive organisms were present in 29 (67%) cases, and Gram-negative organisms were present in 13 (30%) cases. The organisms most commonly isolated from mediastinal culture were Staphylococcus aureus (46%), coagulase-negative staphylococci (17%) and Pseudomonas aeruginosa (17%). The rate of concurrent bacteremia was 53% (95% confidence interval, 38-69%). In multivariable analysis, delayed sternal closure was an independent risk factor for the development of Gram-negative mediastinitis (odds ratio, 9.3; 95% confidence interval, 1.5-56.8; P = 0.016). CONCLUSIONS: Although Gram-positive organisms were the most common cause of infection, Gram-negative organisms accounted for one-third of all isolates. More than one-half of patients with mediastinitis had concurrent bacteremia. Delayed sternal closure was an independent risk factor for Gram-negative mediastinitis.

Bacteremia↗
PubMed2005

Suppurative intracranial complications of sinusitis in previously healthy children.

In this retrospective case series, we describe the clinical features and microbiology of 16 previously healthy children with suppurative intracranial complications of sinusitis. Most cases were male adolescents who presented with vomiting in addition to typical sinusitis symptoms. Neurologic signs were often absent. Streptococcus milleri group organisms, along with anaerobes, were common pathogens.

Adolescent↗
PubMed2005

Staphylococcus aureus as a risk factor for bloodstream infection in children with postoperative mediastinitis.

Bloodstream infection (BSI) complicates postoperative mediastinitis in >50% of cases. In this retrospective cohort study from 1995-2003, postoperative mediastinitis caused by Staphylococcus aureus was an independent risk factor for the development of BSI (adjusted odds ratio, 6.4; 95% confidence interval, 1.4-29.3). Postoperative mediastinitis caused by S. aureus has a higher intrinsic risk of being complicated by BSI than mediastinitis caused by other pathogens.

Adolescent↗
PubMed2005

Risk factors for and outcomes of bloodstream infection caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species in children.

OBJECTIVE: The increasing prevalence of infections caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species (ESBL-EK) has become a growing concern in the hospitalized patient population. Previous studies on risk factors for infection with ESBL-EK have mainly focused on adult populations, and these findings may not be relevant among the pediatric population that experiences a unique set of health care exposures and underlying conditions. The objective of this study was to define the risk factors and outcomes associated with ESBL-EK bloodstream infections in children. METHODS: We conducted a nested case-control study using data from the Children's Hospital of Philadelphia from May 1, 1999, to September 30, 2003. Eligible patients were identified from the hospital database of microbiology laboratory records. All patients with ESBL-EK bloodstream infections were compared to a random sample of patients with non-ESBL-EK bloodstream infections. Risk factors analyzed included prior antimicrobial use, comorbid conditions, and demographic characteristics. Pulsed-field gel electrophoresis was performed to determine genetic relatedness of the ESBL-EK isolates. RESULTS: Thirty-five cases and 105 control subjects were included in the study. The median age among the cases was 2 years (interquartile range: 0-11), compared with 1 year (interquartile range: 0-8) among control subjects. Patients with ESBL-EK infections were 5.8 times (95% confidence interval: 1.9-17.7) more likely to have had exposure to an extended-spectrum cephalosporin in the 30 days before infection than those with non-ESBL-EK infections. Other independent predictors of ESBL-EK infection were being female, infection with a Klebsiella species, and steroid use in the 30 days before infection. All ESBL-EK isolates were susceptible to carbapenem antibiotics. Pulsed-field gel electrophoresis analysis revealed that the ESBL-EK isolates were polyclonal. Although a substantially higher proportion of children with ESBL-EK died (in-hospital mortality: 36% vs 13%), this difference was not statistically significant. CONCLUSIONS: Receipt of extended-spectrum cephalosporins in the 30 days before infection by an Escherichia coli or Klebsiella species is significantly associated with having an ESBL-EK infection in hospitalized children. Curtailed use of cephalosporins among high-risk groups may reduce the occurrence of ESBL-EK infections. Future studies on identifying high-risk children and investigating the impact of curtailed third-generation cephalosporin use to limit additional emergence of ESBL-EK infections should be undertaken.

Analysis of Variance↗
PubMed2003

Risk of bacteremia in young children with pneumonia treated as outpatients.

BACKGROUND: Blood cultures are often obtained as part of the evaluation of children with pneumonia. There are few data regarding the risk of bacteremia with pneumonia in children since introduction of the Haemophilus influenzae type b vaccine. OBJECTIVE: To evaluate the risk of bacteremia in young children with pneumonia who were treated as outpatients. METHODS: A retrospective cohort study of 580 children aged 2 to 24 months who were evaluated by blood culture in a tertiary care children's hospital emergency department between February 1, 1993, and May 31, 1996, and discharged with the diagnosis of pneumonia. RESULTS: The mean patient age was 14.1 months; 339 patients (58.4%) were boys. Thirty-eight patients (6.6%) reported the use of oral antibiotics before initial emergency department evaluation. The prevalence of bacteremia was 1.6% (95% confidence interval, 0.7%-2.9%). Streptococcus pneumoniae was the causative organism in all 9 cases. The serotype was available for 8 of 9 cases. Six (75%) of 8 cases of S pneumoniae bacteremia were caused by serotypes included in the current heptavalent pneumococcal conjugate vaccine, which was not available at the time of this study. The contamination rate was 1.9% (95% confidence interval, 1.0%-3.4%). The mean +/- SD time to blood culture positive for organisms in a continuously monitored system was significantly shorter for pathogens (13.9 +/- 1.3 hours) than for contaminants (21.2 +/- 6.1 hours; P =.01). CONCLUSIONS: Children aged 2 to 24 months with pneumonia who are treated as outpatients are at low risk of bacteremia. Widespread use of the pneumococcal conjugate vaccine may further decrease the incidence of bacteremia in this population.

Bacteremia↗
PubMed2003

Cat scratch disease presenting as orbital abscess and osteomyelitis.

Ocular manifestations of cat scratch disease are uncommon. The diagnosis is usually made on the basis of increasing Bartonella henselae serum antibody titers. We report a child presenting with orbital abscess and osteomyelitis who was diagnosed with hepatosplenic cat scratch disease by detection of B. henselae DNA in the orbital abscess fluid.

Abscess↗
PubMed2002

Low risk of bacteremia in children with febrile seizures.

OBJECTIVE: To evaluate the risk of bacteremia in children with febrile seizures treated as outpatients. METHODS: A retrospective cohort study was performed involving 379 children aged 2 to 24 months presenting to an urban tertiary care children's hospital emergency department with a febrile seizure between February 1, 1993, and May 31, 1996. RESULTS: The mean patient age was 15.9 months, and 217 (57%) were male. In 40 patients (10.6%), the use of oral antibiotics before initial emergency department evaluation was reported. Bacteremia occurred in 8 (2.1%) of 379 children studied. None of the children with bacteremia had received previous antibiotics. The causative organisms were Streptococcus pneumoniae in 7 cases and group A Streptococcus in 1 case. There were 5 contaminated cultures (1.3%). Although 2 of the 8 children with bacteremia ultimately required admission, there were no serious adverse outcomes. Six of 7 episodes of S pneumoniae bacteremia were caused by serotypes included in the pneumococcal conjugate vaccine, which was not available at the time of this study. CONCLUSIONS: Children 2 to 24 months of age with febrile seizures are at similar risk for occult bacteremia as those with fever alone. Widespread use of the pneumococcal conjugate vaccine may further decrease the incidence of bacteremia in this population.

Bacteremia↗
PubMed2002

Appropriate use of antibiotics for common infections in an era of increasing resistance.

In many respects, antibiotics have changed medicine forever. Countless lives have been enhanced and saved with antibiotic use. Unfortunately, the medical community has opened Pandora's box through the casual distribution of outpatient antibiotics. Society will indeed suffer, as well as the medical profession, if antibiotics are not used judiciously. To date, the rate of penicillin resistance has steadily risen in North America and in many other areas of the world. Much of the increase in resistance has been caused by the distribution of antibiotics for viral infections (e.g., bronchitis, colds, or purulent nasal discharge) as well as nonstreptococcal throat infections. Parental pressure for physicians to prescribe antibiotics also has contributed to the rise in antibiotic resistance. The authors have discussed many common pediatric ED infections and have illustrated the key points for making the diagnosis of each. In addition, the authors also recommend the appropriate choice of antibiotics for each disease process, with an emphasis on narrow-spectrum, first-line antimicrobials. Physicians, as the "holders of the prescription pad," should be aware of the problems with increasing bacterial resistance especially ED practitioners who work on the front line. In addition, families and patients should be educated about the harm of inappropriate antibiotic use. The AAP publishes pamphlets for parents that discuss these issues. It is believed, as was seen in Finland and Japan, that judicious use of antibiotics leads to a decrease in resistant bacteria and prolong antibiotic usefulness. This is an issue of great importance to the long-term health of patients. What Benjamin Rush stated in 1789 is true today: "Do not condemn, or oppose, unnecessarily, the simple, prescriptions of your patients. Yield to them in matters of little consequence but maintain an inflexible authority over matters that are essential to life."

Adolescent↗
PubMed2002

An outbreak of Serratia marcescens bacteremia after general anesthesia.

OBJECTIVE: To investigate an outbreak of Serratia marcescens bacteremia among patients after general anesthesia. DESIGN: A case-control study. SETTING: A 304-bed, pediatric teaching hospital. PATIENTS: Twenty-three pediatric patients who developed S. marcescens bacteremia within 2 weeks after general anesthesia between June 15 and September 22, 1999, were compared with 46 age-matched control-patients who had undergone procedures on the same clinical services of the hospital during the same period. RESULTS: Cases were distributed over a wide range of surgical services and were not correlated with exposure to any of the surgical, anesthesia, or nursing staff. Case-patients were significantly more likely than control-patients to have received cefazolin (odds ratio [OR], 11.1; 90% confidence interval [CI90], 1.9 to 24.3) or to have had perioperative placement of a central vascular catheter (OR, 4.2; CI90, 1.2 to 18.8). The timing of the procedures of patients who subsequently developed S. marcescens bacteremia was significantly associated with the shifts of one or more of five operating room technicians (OR, 2.9 to 6.8) who were responsible for preparing intravenous fluids used both to reconstitute perioperatively administered antibiotics and to prime central vascular catheter assemblies. CONCLUSIONS: Our findings are consistent with a pattern of intermittent contamination due to periodic breaches in sterile technique, rather than a point-source of contamination. The unique challenges that such a procedural breakdown presents to an epidemiologic investigation are discussed. This outbreak stresses the importance of providing comprehensive training in antisepsis when multifunctional personnel are incorporated into an operating room work environment.

Adolescent↗
PubMedDate not supplied

Factitious fungus in two children with cancer receiving liposomal amphotericin.

Amphotericin B deoxycholate and liposomal formulations of amphotericin are often started and continued empirically, in immunocompromised hosts, based on the computed tomography findings and the patient's clinical picture. The authors describe two patients with presumed fungal pulmonary nodules, which were progressive despite prolonged treatment with liposomal amphotericin B. At subsequent biopsy, neither had evidence of active fungal disease; rather, the nodules revealed reactive changes and lipid-laden macrophages. These cases underscore the importance of establishing a microbiologic diagnosis in cases of presumed fungal infection.

Adolescent↗