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Edward O Mason

Publications and source records attributed to Edward O Mason.

36 records · Page 2Linked to original sources
PubMed2004

Community-acquired, methicillin-resistant and methicillin-susceptible Staphylococcus aureus musculoskeletal infections in children.

BACKGROUND: The clinical characteristics and virulence factors related to musculoskeletal infections caused by community-acquired, methicillin-resistant Staphylococcus aureus (MRSA) in children are not well-defined. METHODS: In this retrospective study, the demographics, hospital course and outcome of children with musculoskeletal infections were reviewed from medical records and by contacting patients or their physicians. Antimicrobial susceptibilities were determined by disk diffusion. Polymerase chain reaction was performed to detect genes encoding for virulence factors. Mann-Whitney, chi2 and Kaplan-Meier tests were used for statistical analysis. RESULTS: Community-acquired MRSA and community-acquired methicillin-susceptible S. aureus (MSSA) caused musculoskeletal infections in 31 and 28 children, respectively. The median numbers of febrile days after start of therapy were 4 and 1 for MRSA and MSSA patients, respectively (P = 0.001). The median numbers of hospital days were 13 and 8 for the MRSA and MSSA groups, respectively (P = 0.014). At follow-up, 2 patients in the MRSA and 1 in the MSSA group had developed chronic osteomyelitis. pvl and fnbB genes were found in 87 and 90% versus 24 and 64% in the MRSA versus MSSA groups, respectively. (P = 0.00001 and 0.017). Ten patients with pvl-positive strains had complications versus no patients with pvl-negative isolates (P = 0.002). CONCLUSIONS: Febrile days and hospital days were greater in children with musculoskeletal infection caused by MRSA than in those affected by MSSA, but no significant differences were found in the final outcome. pvl and fnbB genes were more frequent in the MRSA than in the MSSA strains. The presence of the pvl gene may be related to an increased likelihood of complications in children with S. aureus musculoskeletal infections.

Adolescent↗
PubMed2004

Clonality of Streptococcus pneumoniae serotype 1 isolates from pediatric patients in the United States.

We compared Streptococcus pneumoniae serotype 1 isolates causing disease among children in six geographic regions of the United States to determine genetic relatedness. Genomic fingerprints were determined by repetitive element polymorphism PCR (Rep-PCR). Multilocus sequence type characterization was performed on selected isolates. Four different genomic banding patterns were identified by Rep-PCR. One profile (clone 1) was predominant and matched sequence type 227.

Adolescent↗
PubMed2004

Decrease of invasive pneumococcal infections in children among 8 children's hospitals in the United States after the introduction of the 7-valent pneumococcal conjugate vaccine.

OBJECTIVE: To monitor clinical and microbiologic features including antimicrobial susceptibility and serogroup distribution of invasive infections caused by Streptococcus pneumoniae among children before and after the introduction of routine administration of the 7-valent pneumococcal conjugate vaccine (PCV7). DESIGN: A 9-year (January 1, 1994 through December 31, 2002) prospective surveillance study of all invasive pneumococcal infections in children. PATIENTS: Infants and children cared for at 8 children's hospitals in the United States with culture-proven invasive infections caused by S pneumoniae. RESULTS: When compared with the mean of the years 1994 to 2000, the annual number of invasive pneumococcal infections for children < or =24 months of age declined 58% in 2001 and 66% in 2002. If only the serogroups in the PCV7 are considered, the number of cases in children < or =24 months old declined 63% and 77% in 2001 and 2002, respectively. The greatest decrease was observed for serogroup-14 isolates. The number of isolates in nonvaccine serogroups increased 28% in 2001 and 66% in 2002 for children < or =24 months old. Nonvaccine serogroup-15 and -33 isolates had the greatest increase in number. The proportion of all isolates nonsusceptible to penicillin increased yearly from 1994 to 2000, reached a plateau in 2001 at 45%, and declined to 33% in 2002. Decrease in nonsusceptibility to penicillin occurred entirely in the isolates with penicillin minimum inhibitory concentration > or =2 microg/mL. Nonsusceptibility to penicillin increased slightly among nonvaccine-serotype isolates. Most infections after at least 2 doses of PCV7 were caused by nonvaccine-serotype isolates. CONCLUSIONS: Since the introduction of the PCV7, the number of invasive pneumococcal infections caused by vaccine-serogroup isolates among 8 US children's hospitals has decreased >75% among children < or =24 months old. In addition, penicillin resistance decreased in 2002 for the first time since our surveillance began in 1993-1994. However, we have noted that replacement may be developing with serogroups 15 and 33. Furthermore, penicillin resistance seems to be increasing among nonvaccine serogroups. Surveillance must be continued to detect the emergence of changes in the distribution of serotypes as well as antibiotic susceptibility.

Child↗
PubMed2004

Impact of the conjugate pneumococcal vaccine in arkansas.

BACKGROUND: On the basis of the success of the early trials in the prevention of invasive pneumococcal disease in infants and children using a heptavalent conjugate pneumococcal vaccine, the American Academy of Pediatrics recommended in August 2000 that the vaccine be given concurrently with other childhood immunizations. METHODS: Data concerning invasive pneumococcal infections from 1998-2000 were compared with 2001-2003 to assess the impact of the heptavalent pneumococcal conjugate vaccine in Arkansas. Basic demographic data were gathered as well as history of vaccination with the pneumococcal vaccine, underlying medical conditions, site of infection and morbidity and mortality. Pneumococcal isolates were serogrouped or serotyped and penicillin susceptibilities were obtained. RESULTS: The incidence of invasive disease decreased from a high of 5.78/100,000 population to 3.02/100,000 population (P = 0.002). Although the percentage of White patients increased from 2001-2003, the overall incidence of disease did not change. The incidence of disease among Blacks fell from 20.5/100,000 population to 4.9/100,000 population. The greatest decrease of disease occurred in children 24 months of age or younger with the incidence rate falling from 44.2/100,00 population to 8.30/100,000 population (P < 0.02). The incidence among White children 24 months of age or younger fell from 19/100,000 population to 1.8/100,000 population, whereas that of Black children 24 months of age or younger declined from 164/100,000 to 35/100,000. From 1998 to 2000, 3.7/100 cases were from nonvaccine serogroups compared with 44/100 cases from 2001 to 2003 (P < 0.001). In children 24 months of age or younger, the number of nonvaccine isolates increased from 1.3/100 cases to 30.5/100 cases (P < 0.001). Overall 56 (44%) were nonsusceptible to penicillin from 1998 to 2000; that was not significantly different from 2001-2003 when 37 (46%) of 81 isolates were nonsusceptible to penicillin. CONCLUSIONS: A significant decrease of invasive pneumococcal disease has been documented in Arkansas. Of concern, however, is the increasing number of invasive isolates not included in the current vaccine.

Arkansas↗
PubMed2003

Epidemiology of acute otitis media caused by Streptococcus pneumoniae before and after licensure of the 7-valent pneumococcal protein conjugate vaccine.

We studied, by pulsed-field gel electrophoresis, multilocus sequence typing and penicillin-binding protein 2b amplicon-restriction profiles, pneumococcal isolates recovered from children with acute otitis media during 1 January-31 December 1999 and 2001. The proportion of nonvaccine serogroups increased from 14.8% (13/88) to 36.5% (23/63) from 1999 to 2001 (P<.01). Among children who received at least 2 doses of the pneumococcal 7-valent protein conjugate (PNC7) vaccine, 46.7% (7/15) of the isolates had nonvaccine serogroups, compared with 20.8% (26/125) of the isolates from children who did not receive the PNC7 vaccine (P=.05). Overall, the serogroups involved in capsular switching were 6-19-NT, 6-14-35, 15-19, and the 19-Spanish 23F clone. In 1999 and 2001, 30.8% (4/13) and 26.1% (6/23) of the nonvaccine serogroups were implicated in capsular switching, respectively. Continued surveillance will be of great importance as the distribution of the PNC7 vaccine increases.

Acute Disease↗
PubMed2003

Infectious exacerbations of chronic obstructive pulmonary disease associated with respiratory viruses and non-typeable Haemophilus influenzae.

Infectious exacerbations of chronic obstructive pulmonary disease (COPD) have been reported to occur with both viral and bacterial pathogens. In this study, 35 exacerbations associated with the isolation of non-typeable Haemophilus influenzae from sputum were identified as part of a prospective longitudinal study. Samples from these patients were subjected to immunoassays to identify a new immune response to the homologous isolate of non-typeable H. influenzae to more accurately assess a bacterial etiology. These patients also were studied carefully for evidence of viral infection using viral culture, serology and polymerase chain reaction-based assays. Sixteen of 35 exacerbations (45.7%) were associated with evidence of acute viral infection and 11 of the 35 exacerbations (31.4%) were associated with the development of new serum IgG to homologous non-typeable H. influenzae. Overall, evidence of infection with a respiratory virus or non-typeable H. influenzae was seen in 24 of 35 exacerbations (68.6%). No association between viral infection and immune response to non-typeable H. influenzae was observed, although a trend toward an immune response to non-typeable H. influenzae and absence of viral infection was seen. The results show that exacerbations in adults with COPD were associated with infection caused by virus alone, non-typeable H. influenzae alone, or virus and non-typeable H. influenzae simultaneously.

Antibodies, Bacterial↗
PubMed2003

Macrolide resistance among middle ear isolates of Streptococcus pneumoniae observed at eight United States pediatric centers: prevalence of M and MLSB phenotypes.

BACKGROUND: Increasing macrolide resistance among middle ear isolates complicates treatment of otitis media in children. When macrolide resistance is mediated via an efflux pump (M phenotype), the MICs of erythromycin, clarithromycin and azithromycin are usually below 32 microg/ml, and the pneumococcus remains susceptible to clindamycin. The association of prior specific macrolide therapy with the isolation of a macrolide resistant strain has not been reported. OBJECTIVES: To determine the mechanism of macrolide resistance in Streptococcus pneumoniae recovered from the middle ears of children with otitis media and their association, if any, with ethnicity, age, serogroup/serotype and prior antibiotic therapy. METHODS: Middle ear isolates collected by members of the United States Pediatric Multicenter Pneumococcal Surveillance Group during a 6-year period from September 1994 through August 2000 were studied. Antibiotic susceptibility to penicillin and ceftriaxone was determined by microbroth dilution. Disc diffusion susceptibility to erythromycin and clindamycin was performed to categorize macrolide resistance mechanisms. The medical record was reviewed to determine demographics and history of previous antibiotic therapy. Isolates were serogrouped or serotyped by the capsular swelling method. RESULTS: Of the 1088 isolates available for testing, 51% were nonsusceptible to penicillin and 37% were nonsusceptible to erythromycin. Erythromycin resistance increased form 15% in 1994 through 1995 to 56% in 1999 through 2000. Seventy-five percent of macrolide-resistant strains were M phenotype. Macrolide resistance was less likely in isolates recovered from African-Americans and more likely in isolates obtained from children <3 years of age and from isolates obtained at time of tympanostomy tube placement. Neither erythromycin, nor clarithromycin nor azithromycin prescribed in the 30 days before infection was more likely than another to be associated with increased macrolide resistance. However, any macrolide alone or in combination with another antimicrobial taken before infection was associated with increased macrolide resistance among the S. pneumoniae organisms isolated from the middle ear. CONCLUSIONS: Macrolide resistance among middle ear isolates of S. pneumoniae increased during the 6-year study. The proportion of M phenotype remained constant at 75%, meaning that these isolates remain susceptible to clindamycin. Continued surveillance to document potential changes is essential.

Anti-Bacterial Agents↗
PubMed2003

Clindamycin treatment of invasive infections caused by community-acquired, methicillin-resistant and methicillin-susceptible Staphylococcus aureus in children.

BACKGROUND: Community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA) is an established pathogen in several areas of the United States, but experience with clindamycin for the treatment of invasive MRSA infections is limited. We compared the outcome of therapy for MRSA with that of methicillin-susceptible (MSSA) invasive infections in children treated with clindamycin, vancomycin or beta-lactam antibiotics. METHODS: The demographics, hospital course and outcome of children at Texas Children's Hospital between February and November 2000 and between August 2001 and August 2002 with invasive S. aureus infections were reviewed from medical records in this retrospective study. RESULTS: CA-MRSA and community-acquired methicillin-susceptible S. aureus (MSSA) caused invasive infections in 46 and 53 children, respectively. The median ages (range) of the children were: MRSA, 3.5 years (2 months to 18.6 years); MSSA, 4.8 years (3 months to 19.8 years). The sites of infection for MRSA vs. MSSA isolates, respectively, were: bacteremia, 3 vs. 6; osteomyelitis, 14 vs. 14; septic arthritis, 5 vs. 7; pneumonia, 11 vs. 3; lymphadenitis, 7 vs. 14; other, 5 vs. 8. Among MRSA patients 39 (20 received clindamycin only, 18 had vancomycin initially and 8 were treated with a beta-lactam initially) received clindamycin and 6 received vancomycin as primary therapy. Among MSSA patients, clindamycin, nafcillin or other beta-lactam antibiotics were used in 24, 18 and 9, respectively. The median number of febrile days was 3 (0 to 14) and 2 (0 to 6) for MRSA and MSSA patients, respectively (P = 0.07). The median number of days with positive blood cultures was 2 for the MRSA (n = 16) and 1 for the MSSA (n = 18) patients (P = 0.04). CONCLUSION: Clindamycin was effective in treating children with invasive infections caused by susceptible CA-MRSA isolates.

Adolescent↗
PubMed2003

In vitro activities of cethromycin (ABT-773), a new ketolide, against Streptococcus pneumoniae strains that are not susceptible to penicillin or macrolides.

Pneumococcal resistance to antimicrobials presents problems to physicians for empirical treatment of acute otitis media (AOM). Three hundred thirty-three isolates of Streptococcus pneumoniae selected for nonsusceptibility to penicillin (MIC >0.1 microg/ml) from the middle ear (n = 325) or mastoid (n = 8) of children seen between 1994 and 2000 at four children's hospitals in the United States were tested by broth microdilution for susceptibility to nine antibiotics. Using NCCLS 2002 breakpoints, resistance to the following drugs was as indicated: amoxicillin, 1%; azithromycin, 71%; cefprozil, 71%; ceftriaxone, 2%; cefdinir, 98%; erythromycin, 70%; levofloxacin, 0%; and trimethoprim-sulfamethoxazole, 93%. Of the penicillin- and erythromycin-nonsusceptible isolates, 97% were inhibited by cethromycin (ABT-773) and 83% were inhibited by telithromycin at a concentration of <or=0.125 microg/ml. Macrolide resistance among penicillin-nonsusceptible pneumococci increased from 44 to 80% in the 6 years of the study from which the isolates were selected; however, the proportion of isolates with M or MLS(B) phenotypes remained constant over the time period (53 and 18%, respectively). Prior treatment with a macrolide or clindamycin alone or in combination with a beta-lactam resulted in 94 or 85% of isolates causing infections being macrolide and or clindamycin resistant. No prior individual macrolide (azithromycin, erythromycin, or clarithromycin) resulted in more macrolide resistance or in a more prevalent resistance phenotype. The ketolides appear to be active antimicrobials against penicillin- and macrolide-resistant pneumococci.

Anti-Bacterial Agents↗
PubMed2003

Streptococcus pneumoniae infections in the neonate.

OBJECTIVE: Streptococcus pneumoniae infections in the neonate (SPIN) are relatively unusual events (1%-11% of neonatal sepsis) but are associated with substantial morbidity and mortality. Previous reports suggest that invasive SPIN is associated with prolonged rupture of membranes, maternal colonization/illness, prematurity, early-onset pneumonia presentation (<72 hours), and high mortality (50%). The aim of this study was to review the current epidemiology and clinical course of SPIN. METHODS: The US Pediatric Multicenter Pneumococcal Surveillance Group has been prospectively monitoring S pneumoniae infections since 1993 in 8 children's hospitals. For this report, data were gathered retrospectively from the charts of neonates who were 30 days of age and younger and had SPIN from September 1993 to February 2001. All pneumococcal isolates were sent to a central laboratory for serogrouping/typing and susceptibility testing. RESULTS: Twenty-nine cases of SPIN were identified from a total of 4428 episodes of S pneumoniae infection in children. Sixty-six percent were male, and 55% were white; the mean age was 18.1 day (+/-8.2). Ninety percent of infants were >or=38 weeks' gestation. Two mothers had bacterial infections at delivery; 1 had S pneumoniae isolated from both blood and cervix, and 1 had clinical amnionitis. The primary diagnoses in the neonates were bacteremia (8), meningitis (8), bacteremic pneumonia (4), septic arthritis/osteomyelitis (1), and otitis media (8). Thirty percent of infants with invasive SPIN presented with leukopenia/neutropenia, but this did not predict poor outcome. The infecting pneumococcal serogroups were 19 (32%); 9 (18%); 3 and 18 (11% each); 1, 6, and 14 (7% each); and 5 and 12 (3.5% each). Twenty-six percent of invasive neonatal infections were caused by serogroups 1, 3, 5, and 12, which are not contained in the heptavalent pneumococcal vaccine. In contrast, 6% of invasive nonneonatal disease was caused by these same nonvaccine serogroups. Susceptibility testing demonstrated that 21.4% of isolates were penicillin nonsusceptible and 3.6% were ceftriaxone nonsusceptible. Three (14.3%) neonates with invasive SPIN died; all deaths occurred within 36 hours of presentation. Deaths did not appear to be related to pneumococcal serogroup or susceptibilities. CONCLUSIONS: Compared with previous studies of neonates with pneumococcal infection, this series showed that infants with SPIN were usually 2 to 3 weeks of age at presentation; likely to be full term; and ill with pneumonia, meningitis, and otitis media. This late-onset presentation was associated with an overall mortality rate of 10.3% (14.3% for invasive disease).

Adult↗
PubMed2002

An epidemiological investigation of a sustained high rate of pediatric parapneumonic empyema: risk factors and microbiological associations.

We investigated the increasing incidence of pediatric empyema during the 1990s at Primary Children's Medical Center in Salt Lake City. Of 540 children hospitalized with community-acquired bacterial pneumonia (CAP) who were discharged from 1 July 1993 through 1 July 1999, 153 (28.3%) had empyema. The annual population incidence of empyema increased during the study period from 1 to 5 cases per 100,000 population aged <19 years. Streptococcus pneumoniae was identified as the most common cause of CAP with or without empyema; serotype 1 accounted for 50% of the cases of pneumococcal empyema. Patients with empyema were more likely to be >3 years old, to have > or =7 days of fever, to have varicella, and to have received antibiotics and ibuprofen before admission to the hospital, compared with patients without empyema (P<.0001 for each factor). The increasing incidence of empyema was associated with infection due to S. pneumoniae serotype 1, outpatient treatment with certain antibiotics, ibuprofen use, and varicella.

Child↗
PubMed2002

Six year multicenter surveillance of invasive pneumococcal infections in children.

OBJECTIVE: Monitor clinical and microbiologic features including antimicrobial susceptibility of invasive pneumococcal infections among children. DESIGN: A 6-year (September, 1993, through August, 1999) 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-proved invasive pneumococcal infection. RESULTS: During the 6-year period 2581 episodes of invasive pneumococcal infection occurred in 2498 children. Underlying conditions were present in 29% of the children. Of children without an underlying condition, 15% of the total infections occurred in those 25 to 60 months old. As the ages of the children advanced the proportion of cases classified as bacteremia declined, whereas the proportion classified as pneumonia increased. Also, as the ages of the children increased the proportion of isolates in serotypes/serogroups 1, 3 and 23 increased. whereas the proportion for serotype 14 diminished. During the 6 years of the study, there was a significant increase in the percentage of isolates intermediate or resistant to penicillin (P < 0.000001) or intermediate to ceftriaxone (P < 0.002). By the sixth year of the study, 37 and 11% of the isolates were nonsusceptible to penicillin or ceftriaxone, respectively. Antibiotic use in the 30 days before diagnosis of systemic pneumococcal infection occurred in 30 to 35% of the children for each of the 6 years. The overall case-fatality rate for children with systemic pneumococcal infection was 1.56%. Mortality was greatest in children >60 months old and in those with underlying conditions; mortality was not related to antibiotic susceptibility. CONCLUSIONS: The percentage of pneumococcal isolates recovered from children with systemic infection which were intermediate for penicillin or ceftriaxone or resistant to penicillin increased steadily during the 6-year period. There was also a trend toward increasing rates of resistance to ceftriaxone. The age and serogroup/serotype distributions of our patients support the recommendations to consider administration of the seven valent pneumococcal conjugate vaccine for all children 24 to 59 months old, with special consideration for selected groups.

Age Factors↗
PubMed2002

Invasive pneumococcal infections in children with asplenia.

BACKGROUND: Asplenia is associated with an increased risk of infections caused by Streptococcus pneumoniae. Overwhelming infection can be fulminate and lead to a fatal outcome. OBJECTIVE: To review the epidemiology and clinical course of invasive S. pneumoniae infections in children with asplenia before the release of the conjugate pneumococcal vaccine. METHODS: Children with S. pneumoniae infections from eight children's hospitals in the US were identified prospectively from September, 1993, to August, 1999. Further demographic, medical and microbiologic information was gathered retrospectively from the charts of patients with asplenia. RESULTS: Twenty-two asplenic patients with 26 episodes of invasive S. pneumoniae were identified. This represents 1% of the 2,581 episodes of invasive S. pneumoniae infections identified in our study. Twelve had congenital asplenia (CA), and 10 had undergone surgical splenectomy. Nine of the patients with CA had associated complex congenital heart disease. The median age at first infection was 12.5 months for CA patients as compared with 69 months in children with surgical splenectomy (P < 0.001). Seventy-five percent of those eligible had received the polysaccharide pneumococcal vaccine. The most common serotypes isolated were 6B (8), 23F (7), 18C (2) and 19A (2). Antimicrobial prophylaxis had been prescribed for 82% of the study cohort. Clinical presentations of the 26 episodes included fever (22), shock (7), petechiae or purpura (7), disseminated intravascular coagulation (5) and respiratory distress (5). Clinical illness included bacteremia alone (12), meningitis alone (8), bacteremia with otitis media-sinusitis (3), bacteremia with pneumonia (2) and meningitis with osteomyelitis (1). Five of the 6 patients who died had meningitis. Three of the survivors (19%) had significant morbidity, and all of them had meningitis. Two patients had 2 episodes each, and 1 patient had 3 episodes. All but 1 of the multiple episodes was with a different serotype. Forty-six percent of isolates were nonsusceptible to penicillin, and 19% were nonsusceptible to ceftriaxone. There was no association between antimicrobial resistance and mortality. CONCLUSIONS: Invasive pneumococcal disease in patients with asplenia has a high mortality, especially in those with meningitis. Even though the new conjugate vaccine might increase protection, 19% of patients had disease caused by serotypes not included in the current heptavalent vaccine. Clinicians should continue to be aggressive in evaluating asplenic patients with unexplained fevers.

Child↗
PubMed2002

Prospective comparison of risk factors and demographic and clinical characteristics of community-acquired, methicillin-resistant versus methicillin-susceptible Staphylococcus aureus infection in children.

CONTEXT: Community-acquired, methicillin-resistant (CA-MRSA) infections in children are increasing in frequency for unknown reasons. OBJECTIVES: To compare the presence of risk factors for methicillin resistance between patients with CA-MRSA and community-acquired methicillin-susceptible (CA-MSSA) infection and to compare the presence of risk factors among household contacts of the patients from both groups. To compare the demographic and clinical characteristics between children with CA-MRSA and CA-MSSA infection. DESIGN: Prospective observational study conducted between February 2, 2000 and November 14, 2000, excluding the month of May and the period between September 2 and October 15. SETTING AND PATIENTS: Texas Children's Hospital, Houston, TX; inpatients and outpatients with community-acquired infection. MAIN OUTCOME MEASURES: Proportion of MRSA among all community-acquired infections. The presence of risk factors associated with methicillin resistance among patients, and their household contacts, with CA-MRSA and CA-MSSA. RESULTS: The monthly rates of methicillin resistance of varied between 35 and 51%. CA-MSSA isolates were associated with deep-seated infections significantly more often (30%) than CA-MRSA isolates (11%; P= 0.01). CA-MRSA isolates were generally susceptible to clindamycin and trimethoprim-sulfamethoxazole and resistant to erythromycin. There were no significant differences in the exposure to risk factors between children with CA-MRSA and CA-MSSA infection. No significant risk factors for CA-MRSA were identified among household contacts. CONCLUSIONS: MRSA is an established, community-acquired pathogen in our area. This necessitates a change in empiric therapy of infections suspected to be caused by.

Adolescent↗
PubMed2002

Multinational study of pneumococcal serotypes causing acute otitis media in children.

BACKGROUND: Streptococcus pneumoniae is a major cause of acute otitis media (AOM) in young children. More than 90 immunologically distinct pneumococcal serotypes have been identified, but limited information is available regarding their relative importance in AOM. METHODS: We analyzed nine existing datasets comprising pneumococcal isolates from middle ear fluid samples collected from 1994 through 2000 from 3,232 children with AOM from Finland, France, Greece, Israel, several East European countries, the US and Argentina. We examined the distribution of pneumococcal serotypes in relation to several demographic and epidemiologic variables, including gender, age, antibiotic resistance and source of culture material. RESULTS: The major serotypes identified included 19F and 23F, each comprising 13 to 25% of pneumococcal middle ear fluid isolates in most datasets; 14 and 6B, comprising 6 to 18%; whereas 6A, 19A and 9V each comprised 5 to 10%. Despite differences in location, study design and antibiotic susceptibility, each major serotype was prominent in most age groups of each dataset. Serotypes represented in the 7-valent pneumococcal conjugate vaccine (PCV-7, 4, 6B, 9V, 14, 18C, 19F, 23F) accounted for 60 to 70% of all pneumococcal isolates in the 6- to 59-month age range, but only 40 to 50% of isolates in children <6 or >/=60 months old. Serotype 3 and, in certain datasets, serotypes 1 and 5, were more important in the <6- and >/=60-month age groups. In each age group vaccine-related serotypes (mainly 6A and 19A) comprised an additional 10 to 15% of all pneumococcal isolates. Four serotypes (23F, 19F, 14 and 6B) accounted for 83% of all penicillin-resistant observations. CONCLUSIONS: This analysis of several geographically diverse datasets indicates that a limited number of serotypes, largely represented in PCV-7, accounted for the majority of episodes of pneumococcal AOM in children between 6 and 59 months of age. Certain serotypes appeared to be relatively more significant in children <6 months or >59 months of age.

Age Factors↗
PubMed2002

Clinical characteristics of children with complicated pneumonia caused by Streptococcus pneumoniae.

OBJECTIVE: The frequency of children who are hospitalized with pneumococcal pneumonia complicated by necrosis, empyema/complicated parapneumonic effusion, and lung abscess seems to be increasing. The factors that contribute to this increase are unclear; therefore, the objective of this study was to describe and compare the relative frequency, clinical characteristics, and outcome of hospitalized children with complicated pneumonia with those of children with uncomplicated pneumonia caused by Streptococcus pneumoniae in the era of antibiotic resistance. METHODS: A multicenter, retrospective study of 8 children's hospitals in the United States was undertaken. A total of 368 children who were hospitalized with pneumococcal pneumonia identified from patients enrolled in the US Pediatric Multicenter Pneumococcal Surveillance Study over the period from September 1, 1993, to January 31, 2000 were studied. Demographic and clinical variables, antibiotic susceptibility, pneumococcal serotypes, antimicrobial therapy, and clinical outcome in hospitalized children with complicated versus uncomplicated pneumococcal pneumonia were measured. RESULTS: A total of 368 patients with pneumococcal pneumonia were identified. Of the 368 isolates, 47 (12.8%) were intermediate and 37 (10.1%) were resistant to penicillin; 18 (5%) were intermediate to ceftriaxone, and 9 (2.5%) were resistant to ceftriaxone. A total of 133 patients met the criteria for complicated pneumonia and had a chest tube placed; 56 of these patients subsequently underwent decortication. The proportion of hospitalized patients with complicated pneumococcal pneumonia increased progressively over the study period from 22.6% in 1994 to 53% in 1999. Patients with complicated disease were older (median age: 45 vs 27 months) and significantly more likely to be of white race and have chest pain on presentation compared with patients with uncomplicated disease. Patients who had complicated disease and underwent decortication were more likely to have pleural fluid lactate dehydrogenase levels of >7500 IU/L compared with those patients who had chest tube placement alone. Fifty-three percent of children who were > or =61 months of age and were hospitalized had complicated pneumonia. This group of children accounted overall for 42% of the patients with complicated pneumonia, 48.2% of the patients who subsequently underwent decortication, and 44% of the patients who had received a course of antibiotics before diagnosis. Pneumococcal serotypes 1, 6, 14, and 19 were the most prevalent serotypes causing disease, with serotype 1 causing 24.4% of the complicated cases versus 3.6% of the uncomplicated cases. Ninety-eight percent of the patients in both groups recovered from their pneumonia. Antibiotic resistance was not found to be more prevalent in those patients with complicated disease. CONCLUSIONS: The relative frequency of complicated disease in hospitalized children with pneumococcal pneumonia is increasing. Patients with complicated pneumococcal disease were older and significantly more likely to be of white race compared with those patients with uncomplicated disease. Pneumococcal serotype 1 caused significantly more disease in patients with complicated versus uncomplicated pneumonia. Patients with complicated disease were not more likely to be infected with an antibiotic-resistant isolate.

Anti-Bacterial Agents↗