Three-year multicenter surveillance of systemic pneumococcal infections in children.

OBJECTIVE: To track antibiotic susceptibility of Streptococcus pneumoniae isolates obtained from children with systemic infections and determine outcome of treatment. DESIGN: A 3-year (September 1993 through August 1996) prospective surveillance study of all invasive pneumococcal infections in children. PATIENTS: Infants and children cared for at eight children's hospitals in the United States with culture-proven systemic pneumococcal infection. RESULTS: One thousand two hundred ninety-one episodes of systemic pneumococcal infection were identified in 1255 children. An underlying illness was present in the children for 27% of the episodes. The proportion of isolates that were nonsusceptible to penicillin or ceftriaxone increased annually and nearly doubled throughout the 3-year period; for the last year the percentages of isolates nonsusceptible to penicillin and ceftriaxone were 21% and 9.3%, respectively. There was no difference in mortality between patients with penicillin-susceptible or nonsusceptible isolates. Only 1 of 742 patients with bacteremia had a repeat blood culture that was positive > 1 day after therapy was started. All 24 normal children with bacteremia attributable to isolates resistant to penicillin had resolution of their infection; the most common treatment regimen was a single dose of ceftriaxone followed by an oral antibiotic. CONCLUSIONS: The percentage of pneumococcal isolates nonsusceptible to penicillin and ceftriaxone increased yearly among strains recovered from children with systemic infection. Because empiric antibiotic therapy already has changed for suspected pneumococcal infections, antibiotic resistance has not been associated with increased mortality. Careful monitoring of antibiotic susceptibility and outcome of therapy is necessary to continually reassess current recommendations for treatment.

Citrobacter urinary tract infections in children.

BACKGROUND: Citrobacter species have been described as the etiologic agents in cases of bacteremia, meningitis, diarrhea and brain abscess, but little is known of their role as a cause of urinary tract infections in children. The purpose of this study was to define the role of Citrobacter species in pediatric urinary tract infections. METHODS: The project consisted of a retrospective chart review of microbiologic and medical records of patients younger than 18 years of age with urine cultures positive for Citrobacter species during a 3-year period. RESULTS: Thirty-four patients with 37 infections were included in the review. The average patient age was 6.9 years (range, 1 month to 18 years) and 71% were female. Fifty-six percent of the patients had urinary tract/renal anomalies or neurologic impairment and 26% represented nosocomial infections. Thirty-seven percent of patients were asymptomatic at the time of diagnosis, whereas 63% complained of at least one of the following findings: gastrointestinal symptoms; dysuria; fever; incontinence; penile/vaginal discharge; frequency; flank pain; and hematuria. Twenty-six of the isolates were Citrobacter freundii and 11 were Citrobacter koseri. Blood cultures were obtained in 9 patients and all were negative for Citrobacter isolates. CONCLUSIONS: Although it is uncommon Citrobacter can cause urinary tract infections in the pediatric population, which occur more frequently in children with underlying medical conditions. It appears that treatment similar to that of other gram-negative enteric organisms is the most prudent approach to these children until more information can be gathered.

Extraintestinal salmonellosis in a children's hospital.

BACKGROUND: An increase in the number of patients presenting with extraintestinal salmonellosis has occurred at our institution. The purpose of this study was to review the extraintestinal salmonellosis cases in our institution and to investigate the possible reasons for this increase. METHODS: A retrospective review of patients from 1985 through 1996 was carried out to identify patients with extraintestinal infections with Salmonella. Demographic data were gathered and statistical evaluations comparing differences among groups (1985 to 1989, 1989 to 1992, 1993 to 1996) was done using the G statistic, adjusted (maximum likelihood) chi square or the Fisher's exact test. RESULTS: Thirty-nine patients were identified with extraintestinal salmonellosis and although the number of cases had increased from 8 in 1985 to 1988 to 18 in 1989 to 1992 and 13 from 1993 to 1996, the percentage of cases that were extraintestinal were similar (3.3%, 6%, 4.9%; P > 0.1). Seventy-two percent of patients had underlying risk factors with the most common being age < 3 months (44%), sickle cell anemia (13%) and gastrointestinal surgery (10%). Fever and diarrhea were more common presenting symptoms in patients < 3 months of age than in older patients (P < 0.05). Salmonella typhimurium and Salmonella heidelberg were the most common serotypes isolated and an increasing trend of ampicillin resistance was noted from 0% in 1985 to 1988 to 39% from 1989 to 1992 and 23% from 1993 to 1996. CONCLUSIONS: The reasons for an increasing trend in extraintestinal cases of human salmonellosis at our institution were not identified. This illness continues to occur in infants and children with well-recognized risk factors.

Failure of the conjugate pneumococcal vaccine to prevent recurrent bacteremia in a child with human immunodeficiency virus disease.

Patients with advanced HIV disease have a poor response to some immunizations. A case is presented of a Class C1 HIV-infected child who suffered three episodes of Streptococcus pneumoniae serotype 6B bacteremia despite having received the heptavalent conjugate and 23-valent polysaccharide pneumococcal vaccines. Clinicians should expect some vaccine failures with the heptavalent conjugate vaccine in children with advanced HIV disease.

Routine tuberculin screening of children during hospitalization.

Harris County, TX, which includes Houston, has one of the highest childhood tuberculosis case rates in the United States. For an 11-week period in the spring of 1988 all children admitted to the medical service of the Ben Taub General Hospital in Houston, TX, received a Mantoux skin test consisting of tuberculin purified protein derivative. The purpose was to assess the impact of routine tuberculin screening during hospitalization for acute medical care and to determine whether tuberculin screening in this setting is an effective means of identifying children with asymptomatic tuberculous infection. Of the 432 patients skin tested, 50% were younger than 1 year of age and only 304 were evaluable at 48 hours. Two new positive skin tests were discovered for a positive tuberculin rate of 0.66%. We conclude that even in a high risk region, routine tuberculin screening of all children admitted to the hospital may not be effective.

Invasive pneumococcal infections in pediatric cardiac transplant patients.

BACKGROUND: Bacterial infections cause significant morbidity and mortality in cardiac transplant patients. Because Streptococcus pneumoniae is the most prominent bacterial pathogen of childhood, the objective of this study was to define the role of S. pneumoniae as a pathogen in the cardiac transplant population. METHODS: Medical records of cardiac transplant patients from March, 1990, through November, 2000, were reviewed to identify invasive pneumococcal infections after transplantation. Demographic, clinical and microbiologic data were reviewed. RESULTS: Nine (11%) of 80 patients had 12 episodes of pneumococcal bacteremia for an incidence rate of 39 cases/1,000 patient years. Patients who were African-American, transplanted before 2 years of age and transplanted because of idiopathic dilated cardiomyopathy were at increased risk of invasive pneumococcal disease (P < 0.05). Six patients were eligible for the 23-valent pneumococcal polysaccharide vaccine before their first invasive infection, but only 1 had received it at the recommended age. Most isolates (82%) were penicillin-susceptible, and no single serotype predominated. There were 2 deaths in the study group, but each was unrelated to infection. Three patients (33%) had recurrent invasive disease with a second serotype an average of 12 months after the first infection. CONCLUSIONS: The incidence of pneumococcal bacteremia in cardiac transplant patients is higher than in the general pediatric population. Risks for infection were being African-American, being younger than 2 years at the time of transplant and being transplanted because of idiopathic cardiomyopathy. It is plausible that pneumococcal vaccine would decrease this risk.

Outcome of invasive infections outside the central nervous system caused by Streptococcus pneumoniae isolates nonsusceptible to ceftriazone in children treated with beta-lactam antibiotics.

OBJECTIVE: To determine the outcome of children treated primarily with beta-lactam antibiotics for a systemic infection outside the central nervous system (CNS) caused by isolates of Streptococcus pneumoniae nonsusceptible to ceftriaxone (MIC > or = 1.0 microg/ml). DESIGN: Retrospective review of the medical records of children identified prospectively with invasive infections outside of the CNS caused by isolates of S. pneumoniae that were not susceptible to ceftriaxone between September, 1993, and August, 1999. A subset of this group treated primarily with beta-lactam antibiotics was analyzed for outcome. PATIENTS: Infants and children with pneumococcal infections cared for at eight children's hospitals. RESULTS: Among 2,100 patients with invasive infections outside the CNS caused by S. pneumoniae, 166 had isolates not susceptible to ceftriaxone. One hundred patients treated primarily with beta-lactam antibiotics were identified. From this group 71 and 14 children had bacteremia alone or with pneumonia, respectively, caused by strains with an MIC of 1.0 microg/ml. Bacteremia or pneumonia caused by isolates with a ceftriaxone MIC > or = 2.0 microg/ml occurred in 6 and 5 children, respectively. Three children with septic arthritis and 1 with cellulitis had infections caused by strains with an MIC to ceftriaxone of 1.0 microg/ml. Most were treated with parenteral ceftriaxone, cefotaxime or cefuroxime for one or more doses followed by an oral antibiotic. All but one child were successfully treated. The failure occurred in a child with severe combined immune deficiency and bacteremia (MIC = 1.0 microg/ml) who remained febrile after a single dose of ceftriaxone followed by 12 days of cefprozil. CONCLUSION: Ceftriaxone, cefotaxime or cefuroxime are adequate to treat invasive infections outside the CNS caused by pneumococcal isolates with MICs up to 2.0 microg/ml, a concentration currently considered resistant for these antibiotics by National Committee for Clinical Laboratory Standards breakpoints.

Nosocomial infections during extracorporeal membrane oxygenation.

OBJECTIVE: To examine trends in nosocomial infection associated with Extracorporeal Membrane Oxygenation (ECMO). DESIGN: Retrospective review of all patients who underwent ECMO over a 4-year period at our institution; specifically, examining reasons for placement and duration of time on ECMO, as well as nosocomial infections incurred while on or shortly after discontinuation of support. Infections were considered ECMO-related if the organism was recovered on support or within 7 days from decannulation. Analyses were performed utilizing Pearson's chi-square for dichotomous factors and t-tests for continuous factors. RESULTS: Of 141 patients requiring ECMO support, 90 (64%) survived to hospital discharge. Indication for support included circulatory failure (53%) and non-cardiac (47%). Twenty-six percent of patients developed infections on ECMO. Organisms isolated included: bacterial 20 (54%), fungal 10 (27%), mixed five (14%) and viral two (5%). Infection sites included: blood 13 (35%), urine nine (24%), mixed eight (22%), wound five (14%) and lung two (5%). Seventy-eight percent of infections noted occurred in cardiac patients. Patients with nosocomial infections were supported for a median of 169 h (range, 84-936 h), versus those without nosocomial infection [146 h (range, 50-886 h); P<0.001]. Procedures on ECMO were associated with an increased risk of infection (P<0.001) as was the presence of an open chest (P<0.025). CONCLUSIONS: The incidence of infection in ECMO patients at our institution has not increased significantly since our previous study. Cardiac patients have increased risk for nosocomial infection while on ECMO, which may be in part due to longer cannulation times, as well as increased likelihood of undergoing major procedures or having an open chest.

A number-needed-to-treat analysis of the use of respiratory syncytial virus immune globulin to prevent hospitalization.

OBJECTIVES: To estimate how many infants in selected high-risk subgroups would require treatment with respiratory syncytial virus immune globulin (RSV-IG) to avoid 1 hospital admission and to determine whether this is economically justified. DESIGN: Cost-benefit analysis. Data from 3 randomized controlled trials of RSV-IG are used to estimate the number needed to treat to prevent 1 hospital admission for respiratory syncytial virus infection. The threshold number needed to treat is computed according to a formula incorporating costs and benefits of RSV-IG prophylaxis. Estimates of the willingness to pay were obtained from a sample of 39 health care providers (35 physicians and 4 nurses). MAIN OUTCOME MEASURES: The number needed to treat to prevent 1 hospital admission for respiratory syncytial virus infection. The threshold number needed to treat that would balance costs with benefits. RESULTS: More than 16 (95% confidence interval, 12.5-23.8) infants would need to be treated with RSV-IG to avoid 1 hospital admission for respiratory syncytial virus infection, ranging from 63 for premature infants without chronic lung disease to 12 (confidence interval, 6.3-100.0) for infants with bronchopulmonary dysplasia. A sensitivity analysis of the costs and values of hospital admission for respiratory syncytial virus infection and RSV-IG treatment resulted in a weak recommendation against the treatment of infants with bronchopulmonary dysplasia and strong recommendations that the costs and risks of RSV-IG treatment outweigh the benefits for the combined sample of infants and premature infants without lung disease. CONCLUSIONS: The number-needed-to-treat procedures offer a method to assess evidence of treatment effects and decision rules for whether to accept treatment recommendations. Under plausible assumptions, treatment with RSV-IG is not recommended for infants without lung disease. Institutions can examine cost and benefit assumptions that best fit their own practice setting.

Epidemiology and molecular identification of Salmonella infections in children.

OBJECTIVE: To explore the role of foods and the environment in the development of infections with Salmonella in infants and children. DESIGN: Case-controlled survey and the use of pulsed-field gel electrophoresis to establish DNA fingerprint patterns. SETTING: Ambulatory and hospitalized patients at a children's hospital. PATIENTS OR OTHER PARTICIPANTS: A consecutive sample of children younger than 4 years old who were infected with Salmonella and 3 age-matched controls per patient were to be surveyed. Of the 103 eligible cases of salmonellosis, 90 cases and 264 controls were included in the study. DATA ANALYSIS: Univariate analysis was done using the Mantel-Haenszel chi2 test or the Fisher exact test. The Bonferroni correction was used for multiple comparisons. DNA fingerprints were inspected for identical banding. RESULTS: Results demonstrated similar diets between cases and controls with the exception of more potato or macaroni salad or coleslaw consumption in the control group (P<.001). DNA fingerprints of Salmonella newport and Salmonella typhimurium demonstrated that all cases were due to unique isolates except in 5 instances involving 12 patients. Seven of these patients could be connected geographically. CONCLUSIONS: Most of the cases of salmonellosis in children younger than 4 years are of a sporadic nature and the major source of infection remains unidentified. For patients infected with identical isolates of Salmonella, a common food source could not be incriminated with the methods used. Environmental contamination or other sources of Salmonella are suggested by these epidemiological data.

Use of ceftizoxime screening for the detection of cephalosporin-resistant pneumococci.

Two hundred and ten pneumococcal isolates underwent ceftizoxime disk (30 micrograms) screening to predict cephalosporin resistance. Forty-six isolates failed screening with 36 (78%) demonstrating intermediate/resistant MICs. Sensitivity and specificity were 100 and 95%, respectively. The ceftizoxime disk screen is an effective method of identifying potentially cephalosporin-resistant isolates.

Genetic homogeneity among Listeria monocytogenes strains from infected patients and meat products from two geographic locations determined by phenotyping, ribotyping and PCR analysis of virulence genes.

Thirty Listeria monocytogenes isolates from human patients and foods originated from two different geographic locations without any epidemiological relations were analyzed for their genotypic and phenotypic virulence gene expressions and genetic relatedness. All strains contained virulence genes, inlA, inlB, actA, hlyA, plcA and plcB, with expected product size in PCR assay except for the actA gene. Some strains produced actA gene product of 268 and others 385 bp. Phenotypically, all were hemolytic but showed variable expressions of phospholipase activity. Ribotyping classified isolates into 12 different groups based on the similarity to DuPont Identification numbers (DID), which consisted primarily of clinical or food isolates or both. Cluster analysis also indicated possible existence of clones of L. monocytogenes that are found in food or human hosts or are evenly distributed between these two. Two isolates (F1 from food and CHL1250 from patient) had unique ribotype patterns that were not previously reported in the RiboPrinter database. This study indicates distribution of diverse L. monocytogenes strains in clinical and food environments. The isolates showed 92-99% genetic homogeneity, in spite of their origins from two different geographic locations and environments.

Infections during extracorporeal life support.

Little data exist on the type of infections patients acquire during extracorporeal life support. Through a retrospective analysis of 109 patients who underwent 115 episodes of venoarterial extracorporeal life support, it was determined that nosocomial infections developed in 18 patients (16%). Patients with nosocomial infections were supported for longer periods of time (230 versus 140 hours; P < .05) and were more likely to have an open chest (P = .02) than those who did not have infectious complications. Blood-borne infections occurred most often while patients were cannulated for extracorporeal life support, with urinary tract and wound infections more commonly occurring after decannulation. Fungal organisms were isolated in 50% of nosocomial infections. Patients with blood or wound fungal infections had a higher case-fatality rate than those patients with bacterial complications (P = .03). Because it is unlikely that the duration of extracorporeal life support can be shortened significantly, the authors recommend an increased level of awareness of nosocomial infections in patients on prolonged extracorporeal life support. Further research is needed to assess the effects of antifungal prophylaxis or immune modulation to prevent nosocomial infections.

Invasive non-typeable Haemophilus influenzae diseases in children.

The current approach to patients with invasive non-typeable H. influenza disease is based upon past experience with the type b strains. In areas where clinicians cannot obtain typing information in a timely manner, issues concerning treatment and prophylaxis should be approached as if the patients were infected with a type b strain. This approach will not change until further information becomes available on invasive non-typeable H. influenzae infections in children.

The approach to treatment of invasive pneumococcal disease in the 1990s.

Streptococcus pneumoniae is the most common cause of pediatric invasive infections and an important cause of morbidity and mortality. In the past, S. pneumoniae responded universally to penicillin until nonsusceptible isolates were first noted in the 1960s. Before 1990, penicillin-nonsusceptible isolates remained a minor component of all reported isolates. Since that time, 20-30% of isolates in many centers in the United States and up to 50% of isolates in some other countries are penicillin-nonsusceptible. Of greater concern has been the development of isolates which are nonsusceptible to more than one antimicrobial agent. This review presents data on pediatric invasive pneumococcal disease in Arkansas and outlines the new treatment recommendations which have been developed in response to these problems. Streptococcus pneumoniae is an important pathogen worldwide and is considered the most common etiology of bacterial sinusitis, otitis media, pneumonia, meningitis and bacteremia. Before 1990, 95-96% of pneumococcal isolates were susceptible to penicillin. The first report of penicillin-nonsusceptible S. pneumoniae was made by Hansman and Bullen in 1967, who identified the strain in the sputum of a patient with hypogammaglobulinemia. Soon thereafter, penicillin-nonsusceptible pneumococci were reported in New Guinea and Australia as well. Over the last several years, the incidence of penicillin-nonsusceptible isolates has greatly increased. Of particular concern is the concomitant increase in the number of organisms that are nonsusceptible to more than one antimicrobial agent. Due to the development of such isolates, clinicians are having to approach patients with invasive disease due to pneumococci more cautiously. In an attempt to clarify confusion with terminology, the Centers for Disease Control and Prevention (CDC) have recommended the same nomenclature be used to classify resistance for all organisms: nonsusceptible organisms are those with an MIC (minimal inhibitory concentration) greater than or equal to that defined for the intermediate category of resistance and the term resistant should be reserved for those organisms with an MIC greater than or equal to that defined for the resistant category. Therefore, resistant isolates are a subgroup of the nonsusceptible isolates.

A call for the judicious use of antibiotics.

In the United States alone, more than one-fifth of antibiotic prescriptions written are for viral illnesses. Due to the increasing resistance rates among commonly encountered bacteria, it is imperative that physicians re-examine their prescription writing habits. Physician and patient re-education, better use of diagnostic testing, the use of narrow spectrum antibiotic agents and shorter course therapy are essential for this to occur. The future health of Arkansas residents is dependent upon changes being implemented before it is too late.

Pertussis in Arkansas.

Although the morbidity and mortality due to pertussis has declined, 109 infants and children were diagnosed and reported to the Arkansas Department of Health with pertussis in 1990-1994. Case rates in Arkansas over this five year period were lower than national case rates (0.9/100,000 vs. 1.77/100,000; p < 0.0001) while the case fatality rates were similar. Hospitalization, admissions to the intensive care, and deaths in Arkansas were more commonly demonstrated in children < 1 year of age. Although recent data concerning the safety and efficacy of the acellular vaccines is promising, at this time the primary series should still be given with the whole-cell vaccine until more data becomes available.

A recent measles outbreak in Arkansas.

On a worldwide level, measles is a common infection, especially in developing countries. In the United States, however, the disease has become very uncommon secondary to the widespread use of immunizations. Because of this, many physicians have not had measles themselves, nor have they treated patients for the infection. This relative rarity may delay diagnosis and the institution of appropriate infection control measures, thus resulting in increased numbers of exposed persons. Until measles is eradicated, measures to ensure appropriate immunization and control outbreaks are essential. A recent small outbreak in Arkansas is reported here along with a review of the disease and the measures to control outbreaks.

Seroprevalence of hepatitis B in a cohort of HIV-infected children and adults in Swaziland.

Hepatitis B virus (HBV) is an important co-morbidity in the HIV epidemic. A retrospective chart review was performed of HIV-infected patients with no previous antiretroviral history enrolled in a Swaziland clinic from January 2009 to May 2011. The seroprevalence of HBV surface antigen (HBsAg) was calculated and the data were analyzed using Mann-Whitney U and Fisher's exact tests. A total of 1282 patients were included in analysis. Five hundred were children aged <15 years. Overall HBsAg seroprevalence was 3.7% (1.4% of children and 5.1% of adults). Prevalence in under-5s was low (0.4%). Among adult women and men, prevalence was 4.2% and 9.8%, respectively (P = 0.022). Median alanine aminotransferase level was 19 U/L in the HBsAg-negative adults and 25 U/L in the HBsAg-positive adults (P = 0.005). Given the number of patients found to be HBsAg-positive, especially among adults, it is important for antiretroviral programmes to consider universal screening and strategically utilize medications that have been found effective in treating both HBV and HIV.