Edward O Mason

Baylor College of Medicine, Houston, Texas, United States

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Publications (234)915.38 Total impact

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    ABSTRACT: Introduction: One of the strategies utilized to decrease infections in the hospital setting relies on topical antimicrobials and antiseptics. While their use is beneficial, concerns arise over the potential for developing resistance or tolerance to these agents. We examined nosocomial Staphylococcus aureus isolates from 2007-2013 for the presence of genes associated with tolerance to chlorhexidine. Methods: Isolates and patients were identified from a S. aureus surveillance study at Texas Children's Hospital. Nosocomial S. aureus isolates (infection at ≥ 72 hours of hospitalization) were identified and underwent PCR for the qacA/B and smr genes associated with elevated minimum bactericidal concentrations to chlorhexidine. Molecular typing with PFGE, MLST and agr-typing and review of the medical record were performed. Results: 247 nosocomial S. aureus infections were identified. Overall, 111 isolates carried one or both genes (44.9%). 33.1% were positive for smr and 22.7% for qacA/B; 10.9% of isolates possessed both genes. smr-positive isolates were more often resistant to methicillin, ciprofloxacin and/or clindamycin. qacA/B-positive isolates were more often associated with indwelling central venous catheters and vancomycin MIC ≥ 2 μg/ml. Isolates carrying either gene were associated with the diagnosis of bacteremia. smr-positive isolates more often belonged to ST8. Mupirocin resistance was detected in 2.8% of isolates. Conclusions: Antiseptic tolerant S. aureus are common in our children's hospital and are associated with decreased susceptibility to other systemic antimicrobials as well as bloodstream infections. Further work is needed to understand the implications that these organisms have on the hospital environment and antiseptic use in the future.
    No preview · Article · Dec 2015 · Antimicrobial Agents and Chemotherapy

  • No preview · Article · Dec 2015 · The Pediatric Infectious Disease Journal
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    ABSTRACT: Introduction: Pneumococcal conjugate vaccines (PCV) have indirect effects due to decreased Streptococcus pneumoniae colonization in vaccine recipients. We sought to determine whether the introduction of PCV13 in children led to changes in the epidemiology and clinical manifestations of invasive pneumococcal disease (IPD) in adults. Methods: We described demographics, comorbidities, clinical manifestations, and serotypes of IPD in Utah adults before (November 2009-February 2010) and after (March 2010-March 2012) the introduction of PCV13 in children. We also compare serotypes causing IPD in Utah adults and children. Results: After the introduction of PCV13 in the childhood vaccine program, the proportion of IPD due to PCV13 exclusive serotypes decreased significantly in Utah adults (64-40%, p=0.009), primarily due to a decline in serotype 7F (36-15%, p=0.008). There were non-significant increases in IPD due to Pneumococcal polysaccharide 23 (PPV23) unique serotypes and non-vaccine serotypes, most notably serotype 22F. Changes in the proportions of vaccine and non-vaccine serotypes were similar in adults and children. Meningitis was more commonly due to non-vaccine serotypes relative to non-meningitis cases (47% vs. 18%, p=0.007). When stratified by sex, decreases in PCV13 serotype IPD were only noted in men (76-33%, p=0.001). Conclusions: Serotype epidemiology of IPD in adults closely follows that of children in the PCV13 era. Continued surveillance is needed to confirm whether replacement serotypes will lead to increases in pneumococcal meningitis and whether there are sex differences in the indirect effects of PCV vaccination in children.
    No preview · Article · Dec 2015 · Vaccine
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    ABSTRACT: Staphylococcus aureus infections in the Down syndrome (DS) population have not been well characterized. This study determined clinical and molecular characteristics of S. aureus infections in children with DS followed at Texas Children's Hospital (TCH), from 2001 to 2011. Patients were retrospectively identified from an ongoing S. aureus surveillance study. Medical records were reviewed. Isolates were characterized by antimicrobial susceptibility, pulsed-field gel electrophoresis patterns, and detection of PVL genes (pvl), mupA (high-level mupirocin resistance gene), smr (chlorhexidine resistance conferring gene), and Staphylococcal Chromosomal Cassette mec (SCCmec) type. Twenty-six patients with DS had a total of 34 S. aureus infections (8 recurrent); 61% were MRSA. DS patients represented 16.8 per 10,000 community onset S. aureus infections seen at TCH. Among 26 initial infections 17 were skin and soft tissue (SSTI), 7 were outer or middle ear and 2 were invasive infections. Seventeen patients were hospitalized. Thirteen (65%) of 20 available isolates were USA300, 14 were pvl+, 5 were mupA+, and 8 were smr+. Five of 8 (63%) recurrent infections were ear infections. All 4 recurrent ear isolates available for study were smr+, ciprofloxacin non-susceptible and treated with ciprofloxacin otic drops. S. aureus infections among patients with DS were similar in presentation to other patient groups, except for a greater proportion being associated with ear infections. Seventy percent of ear fluid isolates carried antiseptic and fluoroquinolone resistance genes. A study of a greater number of DS patients is warranted to further explore these findings.
    No preview · Article · Sep 2015 · Journal of Infection and Chemotherapy
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    ABSTRACT: Background: The impact of 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal meningitis (PM) in US children is unknown. We compared the serotype distribution, antibiotic susceptibility, hospital course, and outcomes of children with PM 3 years before and 3 years after the introduction of PCV13. Methods: We identified patients ≤18 years of age with PM at 8 children's hospitals in the United States. Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Clinical data were abstracted from medical records. Patients were divided into 3 subgroups: pre-PCV13 (2007-2009), transitional year (2010), and post-PCV13 (2011-2013). Categorical variables were analyzed by the χ(2) test and continuous variables by the Mann--Whitney U test. Results: During the study period, 173 of 1207 episodes (14%) of invasive pneumococcal disease were identified as PM; 76 of 645 (12%) were during 2007-2009 and 69 of 394 (18%) during 2011-2013 (50% increase; P = .03). The proportion of PCV13 serotype cases decreased from 54% in 2007-2009 to 27% in 2011-2013 (P = .001). Non-PCV13 serotype cases represented 73% of the isolates in 2011-2013. Isolates with ceftriaxone minimum inhibitory concentration ≥1 µg/mL decreased (13% to 3%) from 2007-2009 to 2011-2013 (P = .03). No significant differences were identified for hospital course or outcome, with the exception that a greater proportion of patients had subdural empyema and hemiparesis in 2011-2013. Conclusions: After the introduction of PCV13, the number of cases of PM in children remained unchanged compared with 2007-2009, although the proportion of PCV13 serotypes decreased significantly. Serotype 19A continued to be the most common serotype in 2011-2013. Antibiotic resistance decreased significantly. Morbidity and case-fatality rate due to PM remain substantial.
    No preview · Article · May 2015 · Clinical Infectious Diseases
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    ABSTRACT: A retrospective review of 33 patients comparing community-associated methicillin-resistant Staphylococcus aureus retropharyngeal abscess (RPA) with community-associated methicillin-susceptible S. aureus RPA from 2002-2013 at Texas Children's Hospital revealed most cases of S. aureus RPA have been due to community-associated methicillin-resistant S. aureus, which appears to be associated with a more complicated clinical course than RPA caused by community-associated methicillin-susceptible S. aureus.
    No preview · Article · Apr 2015 · The Pediatric Infectious Disease Journal
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    ABSTRACT: Background: Streptococcus pneumoniae is a common cause of otitis media (OM) in children; mastoiditis remains an important complication of OM. Limited data are available on the impact of the 13-valent pneumococcal conjugate vaccine (PCV13) on pneumococcal otitis. Methods: Investigators from 8 children's hospitals in the United States prospectively collected pneumococcal isolates from middle ear or mastoid cultures from children from 2011 to 2013. Serotype and antibiotic susceptibilities were determined and PCV13 doses for children documented. Results: Over the 3-year period, the proportion of isolates included in PCV13 (plus a related serotype) decreased significantly (P = .0006) among the middle ear/mastoid isolates (2011, 50% [74/149]; 2012, 40.5% [47/116]; 2013, 29% [34/118]). The number of serotype 19A isolates in 2013 (n = 12, 10.2% of total) decreased 76% compared with the number of 19A isolates in 2011 (n = 50, 33.6% of total). Of the children from whom serotype 19A was isolated (n = 93), 55% had previously received <3 doses of PCV13. The most common non-PCV13 serotypes for the combined years were 35B (n = 37), 21 (n = 20), 23B (n = 20), 15B (n = 18), 11 (n = 17), 23A (n = 14), 15A (n = 14), and 15C (n = 14). The proportion of isolates with a penicillin minimal inhibitory concentration >2 µg/mL decreased significantly over the 3 years (2011, 22% [35/154]; 2012, 20% [24/118]; 2013, 10% [12/120]; P < .02). Conclusions: The number of pneumococcal isolates and the percentage of isolates with high-level penicillin resistance from cultures taken from children with OM or mastoiditis for clinical indications have decreased following PCV13 use, largely related to decreases in serotype 19A isolates.
    No preview · Article · Feb 2015 · Clinical Infectious Diseases
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    ABSTRACT: Background Staphylococcus aureus is among the most common causes of healthcare-associated infection (HAI) in the United States. Patients who have received a solid organ transplant (SOT) represent a unique population for the acquisition of HAIs, given their preoperative organ failure, immunosuppression, and need for invasive procedures. However, limited literature is published on S. aureus infections among children with SOT. We describe the epidemiology, antimicrobial susceptibility, and clinical features of S. aureus infections among pediatric SOT recipients.DesignAn ongoing prospective S. aureus surveillance database from 2001 to 2012 was searched for infections in patients with a history of SOT at Texas Children's Hospital. Medical records and antibiotic susceptibility profiles were reviewed; specific attention was applied to the time since transplantation to infection.ResultsOut of the total of 696 transplants performed during the study period, 38 pediatric SOT recipients developed 41 S. aureus infections; the highest incidence of infection was among heart recipients. Overall, the most common infectious diagnoses were skin-and-soft-tissue infections (66.1%), followed by bacteremia (15.3%). Among isolates in SOT patients, 47.5%, 16.9%, and 6.7% were resistant to methicillin, clindamycin, or mupirocin, respectively. Three infections (7.3%) occurred in the early post-transplant period (<1 month), all of which were bacteremia (P = 0.007) and all caused by methicillin-susceptible S. aureus (MSSA). The majority of infections (90.2%) occurred in the late post-transplant period (>6 months). In 10 cases (16.9%), S. aureus infection was associated with graft rejection during the same admission.ConclusionsS. aureus represents an important cause of morbidity in pediatric SOT recipients. While the majority of infections occurred late after transplant (>6 months), those acquired in the early post-transplant period were more often invasive and caused by MSSA in our hospital. Physicians caring for SOT recipients should be aware of the risks posed by this pathogen and the potential concomitant morbidity including graft rejection.
    No preview · Article · Jan 2015 · Transplant Infectious Disease

  • No preview · Conference Paper · Oct 2014
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    ABSTRACT: Background: After the introduction of PCV7 the incidence of pediatric pneumococcal meningitis (PM) decreased significantly. The impact of PCV13 on PM in children is unknown. We compared the serotype (ST) distribution, antibiotic susceptibility and outcomes of children with PM 3 yrs before and 3 yrs after the introduction of PCV13. Methods: We identified patients ≤18 years with PM at 8 children's hospitals in the US (1/1/2007 - 12/31/2013). Pneumococcal isolates were collected prospectively. Serotyping and antibiotic susceptibility were performed in a central laboratory. Clinical and laboratory data were collected retrospectively. Patients were divided into 3 subgroups: pre-PCV13 (2007-2009), transitional year (2010) and post-PCV13 (2011-2013). Dichotomous variables were analyzed by Χ2 test and continuous variables with parametric/non-parametric tests. Results: During the study period, 173 of 1158 (15%) children with invasive pneumococcal disease (IPD) had PM; 76 of 644 (12%) during 2007-2009 and 69 of 344 (20%) during 2011-2013 (+8%, p<0.001) (Figure). We obtained clinical data from 125 patients (72%), of those 7 pneumococcal isolates were not viable for serotyping. In 2010, 22 cases were identified. 2007-2009 2011-2013 p N=103 56 47 Age, mo median (IQR) 16.8 (5-81) 16.3 (6-84) 0.9 Underlying condition (%) 16(29) 17(36) 0.4 CSF WBC (x103/mm3), median (IQR) 1.1 (0.1-2.9) 0.9 (0.1-2.8) 0.9 PCV13 ST 26/54 (48) 12/45 (27) 0.03 ST 19A 10/54 (19) 10/45 (22) 0.7 Penicillin MIC ≥0.12g/ml 13/54 (24) 14/45 (31) 0.4 Ceftriaxone MIC ≥0.5g/ml* 9/54 (17) 9/45 (20) 0.7 Death 1 (1.8) 5 (10.6) 0.08 Intensive care 33 (59) 38(81) 0.02 Fever after admission, days 3.22.4 4.73.7 0.02 *All ST 19A and 35B ST 7F decreased by 13% (p=0.02). The most common non-PCV13 STs during 2011-2013 were 33F (n=5; increased by 11%, p=0.02), 22F and 35B (n=4 each). Other measures of severity were similar during 2007-2009 and 2011-2013. Of all survivors, 46% had neurologic sequelae and 24% had sensorineural hearing loss. Rates of sequelae were similar among PCV13 and non-PCV13 ST cases; and during 2007-2009 and 2011-2013. Conclusion: After the introduction of PCV13, the number of cases of PM per year in children has remained unchanged, but with an increasing proportion of PM among children with IPD. ST 19A continues to be the most common ST in 2011-2013. Rates of morbidity and mortality remain substantial.
    No preview · Conference Paper · Oct 2014
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    ABSTRACT: Background: Following routine use of the 13-valent pneumococcal conjugate vaccine (PCV13, contains PCV7 serotypes [STs] + STs 1, 3, 5, 6A, 7F , 19A), invasive pneumococcal infections (IPI) declined over 40% in 2011 compared to the average number of cases in 2007 to 2009 at 8 children's hospitals in the United States. The most common STs causing IPI in 2011 were 19A, 7F and 33F (Pediatr Infect Dis J 2013;32:203-7). We now report findings for 2012 and 2013. Methods: IPI have been prospectively identified by investigators at 8 children's hospitals in the US since 1993. Demographic and clinical data are collected on case report forms and isolates are sent to a central laboratory where serotyping and antibiotic susceptibilities are performed. Dichotomous variables were analyzed by chi-square. Results: The total number of IPI, most common STs and % of children under 60 months old for each year is shown in the table. The total number of IPI has continued to decrease each year primarily related to declines in ST 19A (P=0.003) and 7F (P=0.02) isolates. However, ST 3 isolates remained at pre-PCV13 numbers. 9 children with ST 19A isolates and 4 children with ST 3 isolates had received 2 or more doses of PCV13 prior to IPI. In 2013, 3 of 12 children had received 4 PCV13 doses prior to ST19A IPI. Only 3 ST 1, 7 ST 19F, and 0 ST 5 isolates were encountered over these 3 years. STs 33F, 22F, 35B, 10, and 15C were the most common non-PCV13 STs. In 2012 and 2013, almost 75% of isolates were non-PCV13 STs. The % of children with underlying conditions was 45-46% each year. The most common conditions were malignancies (n=41), cardiovascular (n=15), genetic (n=14), renal (n=13) and central nervous system (n=10). Non-PCV13 STs accounted for 78% (32/144) of IPI isolates from children with underlying conditions. Isolates 2011 2012 2013 Total 128 112 104 19A 34 (2)* 16 (2) 12 (5) 3 5 (1) 6 (1) 11 (2) 7F 11 3 2 6C 5 3 5 33F 8 10 10 22F 5 9 8 35B 6 4 8 10 3 9 4 15C 3 8 3 23B 2 5 6 23A 4 6 2 12F 3 5 4 % non PCV13 54 73 74 % < 60 mon. 60 63 55 *() number of children who received ≥ 2 doses of PCV13 Conclusion: IPIs among 8 children's hospital continued to decline 2 and 3 years after full implementation of PCV13. STs 19A and 7F cases declined markedly whereas ST3 cases remained unchanged compared with pre-PCV13 findings. The number of non-PCV13 ST isolates has remained steady with STs 33F and 22F being the most common non-PCV13 STs in 2011 to 2013.
    No preview · Conference Paper · Oct 2014

  • No preview · Article · Oct 2014 · Open Forum Infectious Diseases
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    ABSTRACT: Staphylococcus aureus bacteremia without a localizing source in children is not well described. We identified patients with a positive blood culture for S. aureus from an 11-year surveillance study. Thirty-six cases of primary bacteremia were identified accounting for 5.7% of bacteremias. Most patients had comorbidities (86.1%), most commonly immunosuppression (33.3%).
    No preview · Article · May 2014 · The Pediatric Infectious Disease Journal
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    ABSTRACT: The widespread use of the 7-valent pneumococcal conjugate vaccine has been associated with epidemiological changes of mucosal and invasive pneumococcal disease. No study describes the impact of 13-valent pneumococcal conjugate vaccine (PCV13) on chronic sinusitis in children. We describe changes in epidemiology of S. pneumoniae chronic sinusitis after the introduction of PCV13 at Texas Children's Hospital (TCH). We identified patients <18 years with positive sinus culture for S. pneumoniae who underwent endoscopic sinus surgery due to chronic sinusitis from August 2008 to December 2013 at TCH. Isolates were serotyped by the capsular swelling method. Demographic and clinical information was collected retrospectively. The χ2 test and Fisher's exact test were used to analyze dichotomous variables. We identified 91 cases of chronic sinusitis with positive sinus culture for S. pneumoniae. Sixty-one (67%) isolates were non-PCV13 serotypes. PCV13 cases decreased 31% in the post-PCV13 period (p=0.003). Serotype 19A decreased 27% in the post-PCV13 period (p=0.007), but accounted for all the isolates with penicillin MIC ≥ 4µg/ml and ceftriaxone MIC ≥2 µg/ml. Serotypes 19A (38%) and 15C (17%) were the most common in the pre- and post-PCV13 periods, respectively. The most common organism co-isolated was Haemophilus influenzae (52%). Isolation of Prevotella spp. increased in the post-PCV13 period (p=0.02). S. pneumoniae continues to represent an important pathogen in chronic sinusitis in children < 5 years. After the introduction of PCV13, S. pneumoniae isolation declined in children with chronic sinusitis at TCH. We also observed a substantial reduction of PCV13 serotypes, predominantly serotype 19A.
    No preview · Article · Apr 2014 · The Pediatric Infectious Disease Journal
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    ABSTRACT: Topical antimicrobial and antiseptic agents are commonly used in the management of minor skin and soft tissue infections (SSTIs). Resistance to mupirocin has been documented in Staphylococcus aureus isolates causing SSTIs. Data are limited, however, on the prevalence of retapamulin resistance or tolerance to antiseptics. We sought to determine the prevalence of decreased susceptibility to retapamulin and mupirocin as well as the potential for decreased chlorhexidine susceptibility of S. aureus isolates from SSTIs in children. Two hundred isolates from patients with a single SSTI and 200 isolates from patients with ≥3 previous episodes from the years 2010 to 2012 were selected from an S. aureus surveillance study. Screening for retapamulin resistance was performed by the broth macrodilution method; mupirocin MICs were determined by Etest. PCR was performed for the presence of the smr gene associated with elevated MICs/minimum bactericidal concentrations (MBCs) to chlorhexidine. Among the isolates screened, 38 isolates (9.5%) exhibited retapamulin resistance, of which 22 (57.9%) were methicillin-resistant S. aureus (MRSA). Two isolates (0.5%) displayed cross-resistance to retapamulin and linezolid. Thirty-nine isolates (9.8%) were found to have mupirocin resistance. smr-positive S. aureus accounted for 14% of isolates. The proportion of smr-positive organisms increased during the study (P = 0.005). The prevalence of in vitro resistance to topical antimicrobials among S. aureus isolates causing SSTI in healthy children in our community is almost 10%. Retapamulin resistance was associated with cross-resistance to linezolid in 0.5% of isolates. In addition, there was an increase in the proportion of smr-positive isolates. Further research including clinical correlations with these findings is warranted.
    Full-text · Article · Mar 2014 · Antimicrobial Agents and Chemotherapy
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    ABSTRACT: Children with probable community-associated Staphylococcus aureus skin and soft tissue or invasive infections were randomized to routine daily hygienic measures with or without “bleach baths” twice a week for 3 months. Within 12 months, a medically attended recurrence occurred in 84 of 495 (17%) children using bleach baths compared to 103 of 492 (21%) of control participants (P = .15).
    No preview · Article · Nov 2013 · Clinical Infectious Diseases
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    ABSTRACT: Background: Several virulence genes encoding proteins have been suggested as potential vaccine candidates for protection against either pneumococcal carriage or invasive disease. The distribution of these genes across serotypes and genotypes has not been analyzed, following the introduction of the pneumococcal conjugate vaccines (PCV7 and 13). Our study sought virulence genes commonly found in isolates recovered from children in the post-PCV era. Methods: Fifteen pneumococcal genes were selected. Sixty clinical S. pneumoniae isolates from 2001-2012 were selected from our collection; 92% of isolates were obtained post 2007. 49 non-PCV13 and 11 PCV13 serotypes were chosen to maximize the genetic variation among strains and included internationally recognized clones and sequence types (STs) observed among several serotypes. DNA was extracted. Multilocus sequence typing (MLST) was performed. Presence of genes was detected by polymerase chain reaction using primers designed from published sequences. Results: Forty-nine non-PCV13 isolates included serotypes 7C, 8, 10, 11, 12F, 13, 15A, 15B, 15C, 16, 17, 18A, 21, 22F, 23A, 23B, 24, 31, 33A, 33F, 34, 35B, 38, and 4 nontypeable (NT) strains. Eleven PCV13 isolates included serotypes 3, 6A, 18C, 19A, 19F, and 23F. Six genes were present across all strains including the NT S. pneumoniae, while cbpA, lytA, pspA and rrgC were present in less than 25% of the isolates (Table). Genomic diversity was evident by MLST, by which 47 STs were identified. Gene target(n=15) PCR-positive (n=60) pcsB, potD, pppA,sp2108, sp0148, stkP 60 (100%) nanA, pia, plyA, psaA 56-59 (93-98%) phtA 36 (60%) cbpA, lytA 9-13 (15-22%) pspA, rrgC 4-6 (7-10%) Conclusion: This study identified 6 genes encoding potential vaccine candidates that were present in both classic and NT S. pneumoniae representing a wide variety of genotypes. Expanded studies on the prevalence of specific genetic components across a larger number of isolates and genotypes will provide knowledge necessary to select candidates that maximize coverage against pneumococcal isolates.
    No preview · Conference Paper · Oct 2013
  • Spyridon Moraros · Eric Brown · Edward O. Mason · Sheldon L. Kaplan
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    ABSTRACT: Background: Weight has been implicated as a risk factor for symptomatic community-acquired methicillin resistant Staphylococcus aureus (CA-MRSA). Information from Texas Children’s Hospital (TCH) in Houston, TX was used to implement a case-control study to assess weight-for-age percentile (WFA), race and seasonal exposure as risk factors. Methods: A retrospective chart review to collect data from TCH was conducted covering the time period January 1st, 2008 to May 31st, 2011. Cases were confirmed and identified through the S. aureus surveillance study database at TCH and were matched on a 1:1 ratio to controls that were seen by the emergency department for non-infected fractures from June 1st, 2008 to May 31st, 2011. Data abstraction was performed using TCH’s electronic medical records (EMR) system (EPIC ®). Results: Of 702 CA-MRSA identified cases, ages 9 to 16.99, 564 (80.3%) had the variable ‘weight’ present in their EMR, were not duplicates and not determined to be outliers. Cases were randomly matched to a pool of available controls (n=1864) according to age and gender, yielding 539 1:1 matched pairs (95.5% case matching success) and a total study sample size, N=1078. Case median age was 13.38 years with the majority being White (66.05%) and male (59.4%). Adjusted conditional logistic regression analysis of the matched pairs identified the following risk factors to presenting with CA-MRSA infection among pediatric patients, ages 9 to 16.99 years: a) Individual weight in the highest (75th-99.9th) WFA quartile (OR=1.36; 95% confidence interval [CI]=1.06-1.74; P= 0.016), b) Infection during summer months (OR: 1.69; 95% CI=1.2-2.38; P= 0.003), c) patients of African American race/ethnicity (OR= 1.48; 95% CI=1.13-1.95; P= 0.004). Conclusion: Pediatric patients, 9 to 16.99 years of age, in the highest WFA quartile (75th-99.9th), or of African-American race had an associated increased risk of presenting with CA-MRSA infection. Furthermore, children in this population were at a higher risk of contracting CA-MRSA infection during the summer season.
    No preview · Conference Paper · Oct 2013
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    ABSTRACT: Background: Few studies describe age-specific reductions in the proportion of pediatric invasive pneumococcal disease (IPD) caused by serotype 19A and other 13-valent pneumococcal conjugate vaccine (PCV13) serotypes. Methods: Using ecological data, we determined age-specific proportions of IPD caused by serotype 19A and the other serotypes included in PCV13 before (2008-2009) and after (2010-2011) PCV13 introduction. IPD cases were identified from 8 children’s hospitals (US Pediatric Multicenter Pneumococcal Surveillance Group). We compared baseline rates (2008-2009) to the most recent data (2011) using Chi-square tests. Results: Among those aged 0-17 years, the proportion of IPD caused by serotype 19A in 2008-2009, 2010, and 2011 was 37%, 37%, and 28%. The proportion of IPD caused by the other 12 (non-19A) PCV13 serotypes for those same years was 66%, 62%, and 48%. However, reductions were not consistent across age group. Specifically, for those aged 0-1 year, there was a 44% (p<.01) relative reduction in the proportion of IPD caused by PCV13 serotypes, where as the percentage among those aged 2-17 was only 17% (p=.12) (p for interaction =.05). The difference in these two age groups was driven largely by the difference in reduction of the proportion of IPD caused by serotype 19A. While there was a 36% relative decrease (p<.01) in the proportion of IPD caused by serotype 19A among those aged 0-1, there was no change among those aged 2-17 (p=.87) (p for interaction =.04). For the other non-19A PCV13 serotypes, the relative percent reduction (32%, p=.04) did not depend on age group (p for interaction =.86). Only 2 children aged ≥11 had received PCV13. The proportion of children with IPD that had underlying comorbidities increased significantly with increasing age. For ages <1 year, 1-2, 3-5, and 6-17 years, respectively, 27%, 32%, 45%, and 60% of children with IPD had comorbid disease (p-trend<.001). Conclusion: Children aged 0-1 year had significant reductions in both 19A and in the other 12 (non-19A) PCV13 serotypes from 2008 through 2011. Children aged 2-17, however, had a reduction in non-19A PCV13 serotypes, but not 19A. Reasons for this could include lack of early indirect effect, virulence of 19A, and more comorbid disease and low PCV13 utilization in older children.
    No preview · Conference Paper · Oct 2013
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    ABSTRACT: Background: Recurrent infections in normal children caused by community associated S. aureus (CA-SA) occur in up to 50% of patients. Optimal methods for preventing recurrent infections are unknown. Methods: Children with probable CA-SA skin and soft (SSI) or invasive infections at Texas Children’s Hospital were randomized to routine daily hygienic measures plus "bleach baths" (5 ml household bleach per gallon of bath water) twice a week (Bleach) or routine daily hygienic measures alone (Control) for 3 mon. The nose, throat and groin were cultured for SA colonization. A research nurse blinded to treatment contacted families at 2 weeks and 3, 6, and 12 mon. to ask if the child had had a medically attended SSI (MA-SSI). The study was designed to detect a 50% reduction in first recurrent MA-SSI assuming a 14% recurrence rate, 85% rate of + SA clinical culture at enrollment and 20% loss to follow-up with 90% power. Analysis was based on intention to treat. Results: SA was isolated from the initial infection site for 890/987 children enrolled; 557/987 were colonized at ≥ 1 site at enrollment. The groin, nose and throat were colonized in 379, 215, and 167 children, respectively. Selected characteristics are shown in the table. Bleach (n=495) Control (n=492) Median Age years (range) 1.8 (.13-18) 1.9 (.26-19) Site of infection (SSI/Invasive) 466/29 457/35 Isolate MR/MS 347/104 313/121 Within 12 mon. of enrollment, a MA-SSI occurred in 84/495 (17%) of Bleach vs. 103/492 (20.9%) of Control enrollees (log-rank p=0.15). A multivariable Cox proportional hazards regression model was used to simultaneously estimate the risk of a recurrent MA-SSI by treatment and age groups. Bleach patients were about 0.79 times less likely to have a reinfection within 1 year; however, the point estimate was not significant at the 0.05 level (95% CI: 0.59, 1.06). Adjusted for treatment group, the risk of reinfection among patients ≤1.86 years was about 2.1 times> that for patients >1.86 years. The effect of age did not significantly depend on the treatment group (p=0.75). Reinfection was not different in those colonized. Conclusion: The groin was the most common site of colonization at initial infection. Younger children were more likely to have recurrent MA-SSI within 1 year of enrollment. The 20% decrease in MA-SSI recurrences with “Bleach baths” was not statistically significant.
    No preview · Conference Paper · Oct 2013

Publication Stats

9k Citations
915.38 Total Impact Points


  • 1977-2015
    • Baylor College of Medicine
      • • Department of Pediatrics
      • • Section of Infectious Diseases
      Houston, Texas, United States
  • 1981-2014
    • Texas Children's Hospital
      • • Department of Pediatric Radiology
      • • Clinical Care Center
      Houston, Texas, United States
  • 2008
    • Children's Mercy Hospitals and Clinics
      Kansas City, Missouri, United States
  • 2007-2008
    • Baylor University
      Waco, Texas, United States
  • 1998-2006
    • The Ohio State University
      • Department of Pediatrics
      Columbus, Ohio, United States
  • 2003
    • Childrens Hospital of Pittsburgh
      Pittsburgh, Pennsylvania, United States
  • 2002
    • Children's Memorial Hospital
      Chicago, Illinois, United States
  • 1999
    • Arkansas Children's Hospital
      Little Rock, Arkansas, United States
    • University of California, San Diego
      • Department of Medicine
      San Diego, California, United States
  • 1996
    • University of Texas Health Science Center at Houston
      • Department of Pathology and Laboratory Medicine
      Houston, TX, United States
  • 1995
    • Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center
      Torrance, California, United States