Kobkul Chotikanatis

Recurrent intravascular catheter-related bacteremia caused by Delftia acidovorans in a hemodialysis patient

ABSTRACT We report the first case of recurrent intravascular-catheter-related bacteremia in a pediatric hemodialysis patient caused by Delftia acidovorans, previously called Comamonas acidovorans or Pseudomonas acidovorans. The patient had a history of multiple infections of central vascular catheters with other organisms, requiring courses of antibiotics and catheter replacements. Previously reported cases of D. acidovorans infections are reviewed. The isolate appeared to become resistant to cephalosporins after antibiotic treatment, but resistance could not be confirmed with additional testing. In vitro susceptibility testing for cephalosporins is not reliable for this organism.

In Vitro Activity of Nemonoxacin, a Novel Nonfluorinated Quinolone Antibiotic, against Chlamydia trachomatis and Chlamydia pneumoniae

ABSTRACT The in vitro activities of nemonoxacin, levofloxacin, azithromycin, and doxycycline were tested against 10 isolates each of Chlamydia trachomatis and Chlamydia pneumoniae. The MICs at which 90% of the isolates of both C. trachomatis and C. pneumoniae were inhibited (MIC90s) were 0.06 μg/ml (range, 0.03 to 0.13 μg/ml). The minimal bactericidal concentrations at which 90% of the isolates were killed by nemonoxacin (MBC90s) were 0.06 μg/ml for C. trachomatis (range, 0.03 to 0.125 μg/ml) and 0.25 for C. pneumoniae (range, 0.015 to 0.5 μg/ml).

IgE anti Hepatitis B virus surface antigen antibodies detected in serum from inner city asthmatic and non asthmatic children

Viral Hepatitis type B (HBV) is a public health concern, but has not been linked to asthma. Immunoglobulin (Ig) G is involved in HBV immune responses; less is known about IgE antibodies (Abs) against HBV in asthma. Given the importance of HBV, we sought to determine whether HBV vaccine contributes to asthma in children, by stimulating specific IgE production. Total IgE, IgE- or IgG-anti-HBVs Abs were studied in vaccinated pediatric asthmatics and non asthmatics. We found: (1) total IgE was higher in asthmatics; (2) total IgE did not correlate with IgE anti-HBVs; (3) IgE anti-HBVs did correlate with IgG-anti-HBVs in all subjects; (4)IgE- and IgG-HBVs Abs were similar in both groups; (5) IgE- or IgG anti-HBVs Abs did not correlate with age. Our findings indicate that HBV vaccination induces IgE responses in asthmatics and non asthmatics.

Seroprevalence of Chlamydia trachomatis in Inner-City Children and Adolescents—Implications for Vaccine Development

Background Prevention of Chlamydia trachomatis infection is an ideal application for a vaccine program, which should optimally be administered before sexual debut. However, there are limited epidemiologic studies of C. trachomatis infection in an unselected pediatric population since routine screening and treatment of pregnant women was implemented in the United States in 1993. Methods Anonymized serum samples were obtained from children younger than 21 years in 2 medical centers in Brooklyn, New York, from 2013 to 2015. Anti–C. trachomatis IgG antibody was determined by a validated enzyme immunoassay. Infants younger than 1 year were excluded from the final analysis due to interference of maternal antibody. Results One thousand two sera were included in the final analysis. Fifty-seven percent were females. No antibody was detected at younger than 11 years. Anti–C. trachomatis IgG antibody was detected in 11.4% and 5.6% of female and male subjects, respectively, older than 11 years (P = 0.0027), and seropositivity increased with age. There was no significant difference in the distribution of age at infection between the centers (P = 0.432), but a difference was detected between genders (P = 0.012) with a higher percentage of female subjects testing positive. Conclusions Antibody was first detected at 11 years of age, likely coinciding with sexual debut. The prevalence of antibody was higher and appeared earlier in females, mirroring national surveillance trends based on nucleic acid amplification testing. The delay in male antibody detection may be due to biological or behavioral differences between genders. These data are critical in informing potential C. trachomatis vaccine strategies.

Chlamydia pneumoniae-induced tumour necrosis factor alpha responses are lower in children with asthma compared with non-asthma

Introduction Chlamydia pneumoniae respiratory tract infection has been implicated in the pathogenesis of reactive airway disease and asthma. Innate cytokine responses that are protective of infection with intracellular pathogens may be impaired in patients with asthma. Tumour necrosis factor alpha (TNF-α) is a cytokine related to functions of monocytes and may inhibit C. pneumoniae infection. We investigated TNF-α responses in C. pneumoniae-infected peripheral blood mononuclear cells (PBMCs) in patients with asthma and non-asthma, and whether ciprofloxacin, azithromycin or doxycycline affects TNF-α responses. Methods PBMC (1.5×106) from paediatric patients with asthma (n=19) and non-asthmatic controls (n=6) were infected or mock infected for 1 hour with or without C. pneumoniae AR-39 at a multiplicity of infection=0.1, and cultured+ciprofloxacin, azithromycin or doxycycline (0.1 ug/mL) for 48 hours. TNF-α levels were measured in supernatants by ELISA. Results When PBMC from patients with asthma were infected with C. pneumoniae, levels of TNF-α were significantly lower than in subjects without asthma (48 hours) (5.5±5.6, 38.4±53.7; p=0.0113). However, baseline responses (no infection with C. pneumoniae) were similar in asthma and non-asthma (1.0±1.7, 1.1±1.2; p=0.89). When PBMC frompatiens with asthma were infected with C. pneumoniae+ciprofloxacin, azithromycin or doxycycline, TNF-α levels increased (25%–45%); this affect was not observed in PBMC from patients without asthma. Conclusions We identified differences in the quantity of TNF-α produced by C. pneumoniae-infected PBMC in asthma compared with non-asthma.

Pediatric Fistula Initiative: Reducing Bloodstream Infections in an Outpatient Pediatric Hemodialysis Center

Bloodstream infection is a major contributor to morbidity and mortality in children on hemodialysis (HD). From January 2009 through April 2011, the incidence of access-related bloodstream infections (ARBs) in pediatric patients on HD at our hospital was 3.45/1000 patient days. Almost all of these children were receiving HD via central line catheters, and none were receiving HD via arteriovenous fistulas (AVFs). In an effort to reduce the rate of infection in children receiving HD at our institution, we introduced the Pediatric Fistula Initiative, a program to increase creation and use of AVFs in children. Thirty-three children on HD were observed, 9 of whom received AVFs during the study period. The incidence of ARBs decreased to 1.30/1000 patient days (P < .001) during the 24-month intervention period from May 2011 through May 2013.