Pneumococcal Colonization Rates Research Articles

Pneumococcal Colonization in Children With Persistent Asthma: A Retrospective Cohort.

Asthma is the most common chronic medical condition among children ≥5 years of age with invasive pneumococcal disease. How asthma or its management affects pneumococcal colonization is not fully understood. Our objective was to compare pneumococcal colonization rates between children with persistent asthma and children without asthma, and to characterize the pneumococcal serotype distribution. We used nasal mid-turbinate samples obtained per routine care from 5- to 18-year-old children with upper respiratory symptoms from November to April (respiratory seasons) of 2017 to 2018 and 2018 to 2019 in Kansas City, United States. Pneumococcal immunization status, prior antibiotic use and other clinical data were collected. Samples were tested for pneumococcal colonization by real-time polymerase chain reaction targeting lytA gene. Positive samples underwent multiplex serotype-specific polymerase chain reaction assays to determine the serotype. Of 363 children (120 with persistent asthma and 243 without asthma), 87.6% were 5 to 10 years old, 50.1% were female and 74.1% received ≥3 doses of a pneumococcal conjugate vaccine. The pneumococcal colonization rate was lower in children with persistent asthma than in children without asthma (10% versus 18.9%, P = 0.03). The odds of colonization were lower in children with persistent asthma [OR 0.4 (95% confidence interval: 0.2-0.9)] after adjusting for demographic and clinical data. Pneumococcal serotype was confirmed in 77.6% of positive samples; 35.6% of those samples corresponded to PCV13 serotypes and 64.4% to non-PCV13 serotypes. The most common serotypes were 19F (15%), 3 (13%) and 6C/6D (11%). Children with persistent asthma had lower rates of pneumococcal colonization than children without asthma when seeking care for respiratory symptoms.

1331. Pneumococcal Colonization Among Children 5 years of Age and Younger During SARS-CoV-2 Pandemic

Abstract Background Children ≤5 years of age have the highest rates of pneumococcal colonization and play an important role in the spread of pneumococcus. Our objective was to determine whether the public health measures (physical distancing, masking, and shelter-in-place orders) implemented to slow the spread of SARS-CoV-2 pandemic had an impact on pneumococcal colonization rates among children aged ≤5 years with and without respiratory symptoms during the first year of SARS-CoV-2 pandemic (4/1/20 to 3/31/21). Methods This is a single center retrospective cohort study. The study period was divided in 3 four-month periods to represent the initial period of strict adherence to public health measures (period 1: Apr-Jul), relaxation of some of these measures (period 2: Aug-Nov) and Northern hemisphere winter season (period 3: Dec-Mar). We used salvaged mid-turbinate samples obtained as part of routine care from patients without respiratory symptoms but screened for SARS-CoV-2 prior to surgery or aerosol generating procedures (asymptomatic) or from patients with respiratory symptoms tested for SARS-CoV-2 and/or other respiratory viruses (symptomatic). Samples were evaluated for pneumococcal colonization by real-time PCR using CDC lytA primers. Sample size was calculated based on the assumption of lower colonization rates in period 1 and gradual increase (10-15%) in the following study periods. Results A total of 311 patients were included (185 asymptomatic and 126 symptomatic). Demographics, SARS-CoV-2 PCR and pneumococcal colonization results are shown in Table 1. Pneumococcal colonization rates for asymptomatic and symptomatic children were 14% and 22% (p=0.06), respectively. The odds of colonization of asymptomatic children were similar during period 2 (OR 0.96 [95%CI 0.34-2.67]) and period 3 (OR 0.53 [95%CI 0.17-1.62]), using period 1 as reference and after adjusting for age, sex, and SARS-COV-2 results. The odds of colonization of symptomatic children were also similar across the 3 study periods (period 2 OR 1.28 [95%CI 0.41-4.01] and period 3 OR 0.73 [95% CI 0.24-2.18]). Table 1.Characteristics of asymptomatic and symptomatic groups Conclusion Pneumococcal colonization rates were not significantly impacted by public health measures implemented during the first year of the SARS-CoV-2 pandemic and did not correlate with SARS-CoV-2 positivity. Disclosures Liset Olarte, MD, MSc, GSK: Grant/Research Support|Merck: Grant/Research Support|Pfizer: Grant/Research Support|Sanofi: Grant/Research Support Douglas S. Swanson, MD, Merck: Grant/Research Support|Pfizer: Grant/Research Support|Sanofi: Grant/Research Support Brian R. Lee, PhD, MPH, CDC: Grant/Research Support|Merck: Grant/Research Support Christopher J. Harrison, MD, Astellas: Grant/Research Support|GSK: Grant/Research Support|Merck: Grant/Research Support|Pediatric News: Honoraria|Pfizer: Grant/Research Support Rangaraj Selvarangan, BVSc, PhD, D(ABMM), FIDSA, F(AAM), BioFire: Grant/Research Support|Luminex: Grant/Research Support.

Clinical manifestations and outcome of viral acute lower respiratory infection in hospitalised children in Myanmar

BackgroundAcute lower respiratory infection (ALRI) remains the leading cause of death in children worldwide, and viruses have been the major cause of ALRI. In Myanmar, ALRI is associated with high morbidity and mortality in children, and detailed information on ALRI is currently lacking.MethodsThis prospective study investigated the viral aetiologies, clinical manifestations, and outcomes of ALRI in hospitalised children aged 1 month to 12 years at the Yankin Children Hospital, Yangon, Myanmar from May 2017 to April 2019. The sample size was set to 300 patients for each year. Two nasopharyngeal swabs were obtained for the patients with suspected viral ALRI; one for rapid tests for influenza and respiratory syncytial virus (RSV), and the other for real-time PCR for the 16 ALRI-causing viruses. Pneumococcal colonization rates were also investigated using real-time PCR. Clinical information was extracted from the medical records, and enrolled patients were categorised by age and severity for comparison.ResultsAmong the 5463 patients admitted with a diagnosis of ALRI, 570 (10.4%) were enrolled in this study. The median age of the patients was 8 months (interquartile range, 4–15 months). The most common symptoms were cough (93%) and difficulty in breathing (73%), while the most common signs of ALRI were tachypnoea (78%) and chest indrawing (67%). A total of 16 viruses were detected in 502 of 570 patients’ samples (88%), with RSV B (36%) and rhinovirus (28%) being the most commonly detected. Multiple viruses were detected in 221 of 570 samples (37%) collected from 570 patients. Severe ALRI was diagnosed in 107 of 570 patients (19%), and RSV B and human rhinovirus were commonly detected. The mortality rate was 5%; influenza virus A (29%) and RSV B (21%) were commonly detected, and stunting and lack of immunization were frequently observed in such cases. Additionally, 45% (259/570) of the patients had pneumococcal colonization.ConclusionsViral ALRI in hospitalised children with a median of 8 months has significant morbidity and mortality rates in Myanmar. RSV and rhinovirus were the most commonly detected from nasopharyngeal swabs, while influenza virus and RSV were the most frequently associated with fatal cases.

1156. Pneumococcal Colonization in Children with Persistent Asthma and without Asthma

BackgroundThe most common underlying medical condition among children ≥ 5 years of age with invasive pneumococcal disease is asthma. How asthma affects pneumococcal colonization is not fully understood. Our objective was to compare pneumococcal colonization rates in children with persistent asthma vs. without asthma.MethodsThis is a single center retrospective cohort study. We used salvage mid-turbinate samples testing negative for influenza per routine care from 5-18 year-olds with upper respiratory symptoms or febrile illness during 2017-18 and 2018-19 northern hemisphere respiratory seasons (November to April). Analyzed groups were those with persistent asthma or those without asthma. Samples were evaluated for pneumococcal colonization by real-time PCR using CDC lytA primers (positive Ct ≤ 35). Positive samples were further tested with multiplex serotype-specific PCR assays to determine pneumococcal serotype. ResultsOf 363 children (120 with persistent asthma and 243 without asthma), 87.6% were 5-10 years old; and 49.9% were male. Fifty percent of samples were from January-February. Pneumococcal colonization rate was lower in children with persistent asthma (10%) vs. without asthma (18.9%) (p=0.03). The odds of colonization were lower in children with persistent asthma (OR 0.4 [95%CI 0.2-0.9]) after adjusting for age, sex, clinic site, smoking exposure, and number of pneumococcal vaccine doses. Colonized patients without asthma were younger than the other groups (Table 1). Pneumococcal serotype/serogroup was assigned in 45 (77.6%) positive samples; 16 (36%) samples corresponded to PCV13 serotypes and 29 (64%) samples to non-PCV13 serotypes. The most common serotypes were: 19F (n=7), 3 (n=6), 6C/6D (n=5), 23B (n=4), 33F/33A/37 (n=4), 35B (n=3), 22F/22A (n=3), 23A (n=3).Table 1 ConclusionPatients with persistent asthma had lower rates of pneumococcal colonization than patients without asthma during respiratory season. Disclosures Liset Olarte, MD, MSc, GSK (Research Grant or Support)Merck (Research Grant or Support)Pfizer (Research Grant or Support)Sanofi (Research Grant or Support) Douglas S. Swanson, MD, Merck (Research Grant or Support)Pfizer (Research Grant or Support)Sanofi (Research Grant or Support) Brian R. Lee, PhD, MPH , Merck (Grant/Research Support)Pfizer (Grant/Research Support) Christopher J. Harrison, MD, GSK (Grant/Research Support)Merck (Grant/Research Support)Pfizer (Grant/Research Support, Scientific Research Study Investigator, Research Grant or Support)

Impact of 13-Valent Pneumococcal Conjugate Vaccine on Nasopharyngeal Carriage Rates of Streptococcus pneumoniae in a Rural Community in the Dominican Republic.

Background Invasive pneumococcal disease (IPD) leads to thousands of pediatric deaths annually. Pneumococcal colonization precedes IPD. In 2013, the Dominican Republic introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into its routine infant immunization program, with doses at ages 2, 4, and 12 months. Prevalence of pneumococcal nasopharyngeal colonization was evaluated post–PCV13 introduction.MethodsA prospective cohort study of 125 children aged 2–35 months was conducted in a rural Dominican Republic community November 2016 through July 2017. Nasopharyngeal swabs and clinical and vaccination data were collected at enrollment and 4–6 months later. Serotypes included in PCV13 were defined as vaccine-type. Colonization rates and serotype distribution were compared at baseline and follow-up, and the association between colonization and vaccination status among the entire cohort was evaluated at each time point.ResultsOf 125 children enrolled, 118 (94%) completed follow-up. Overall and vaccine-type pneumococcal colonization rates were 62% and 25%, respectively, at baseline and 60% and 28% at follow-up. Among children age-eligible for 3 doses, 50% and 51% were fully vaccinated at baseline and follow-up, respectively. At baseline assessment, children up-to-date for age for PCV13 were less likely to be colonized with vaccine-type pneumococci than children not up-to-date, and the same was found for fully vaccinated children (3 doses) compared to those not fully vaccinated (odds ratios [ORs], 0.38 [95% confidence interval {CI}, .18–.79], and 0.14 [95% CI, .04–.45], respectively). The same associations were not found at follow-up assessment.ConclusionsThree years post -PCV13 introduction, vaccine-type colonization rates remained high. Low vaccination coverage for 3 PCV13 doses may have contributed. The protective effect of PCV13 on vaccine-type carriage suggests an increase in PCV13 coverage could lead to substantial declines in pneumococcal vaccine-type carriage.

Pneumococcal colonization in healthy and hospitalized Sri Lankan children between 2 months to 2 years

Background: Colonization with Streptococcus pneumoniae is considered a pre-requisite for pneumococcal diseases. Evaluating the pneumococcal isolates that colonize children will give surrogate data on the circulating serotypes in the country. This study was conducted to identify the pneumococcal colonization rates among healthy children between 2 months and 2 years of age and children of the same age group who are hospitalized with respiratory symptoms identify the serotypes and sensitivities of the pneumococcal isolates Methods & Materials: This prospective descriptive study was conducted among two cohorts of children aged between 2 months and 2 years. (A) Healthy children attending immunization clinics and (B) children hospitalized with respiratory symptoms with or without fever. A nasopharyngeal swab (NPS) was collected from all participants. The NPS was cultured on sheep blood agar and pneumococcal isolates were identified with Optochin sensitivity and bile solubility testing. Microbroth dilution was used to determine sensitivity for cefotaxime and penicillin while disc diffusion was used to determine sensitivity for erythromycin and tetracycline. Multiplex PCRs prescribed by CDC and others were used to identify serotypes and serogroups. Results: Three hundred children each were recruited from the healthy cohort (HC) and inward cohort (IC). Pneumococcal colonization rate for the HC was 29.3% (n = 88) while it was 39.0% (n = 117) among the IC (p = 0.008, Chi-square test). The predominant serotypes identified were 19F (n = 45, 22.0%), 6B (n = 26, 12.7%), 23F (n = 21, 10.2%) and 6A (n = 19, 9.3%). Considering all 131 pneumococcal isolates together, penicillin MIC ranged from 0.015 to 4 while the cefotaxime MIC ranged from 0.015 to 16. MIC50 and MIC90 for penicillin and cefotaxime were 1 and 2 μg/mL. Non susceptibility rates for tetracycline and erythromycin were 70.7% and 75.1% respectively. Conclusion: Pneumococcal colonization rates found were considerably higher and the predominant serotypes identified 19F, 6B, 23F and 6A. Subtyping to serogroup 6 is ongoing. Acknowledgements: Research grant WI216479 through Pfizer for financial assistance.

Pneumococcal colonization among healthy and hospitalized vaccine-naive Sri Lankan children

BackgroundStreptococcus pneumoniae continues to cause mortality and morbidity despite availability of effective vaccines. Pneumococcal colonization is considered a pre-requisite for disease. Identifying the serotypes circulating in a given locale is important for surveillance purposes as well as for assessing the need for vaccination.Aim of the present study was to identify nasopharyngeal pneumococcal colonization rates in healthy children and children with respiratory tract infections in central Sri Lanka. MethodA total of 450 nasopharyngeal swabs (NPS) of children aged between 2 months and 2 years were collected from two groups; healthy children and children hospitalized with respiratory symptoms. NPS samples were processed using conventional laboratory techniques to isolate S. pneumoniae. Antibiotic susceptibility patterns of pneumococcal isolates were identified using CLSI disc diffusion method and minimum inhibitory concentration (MIC) was determined by micro-broth dilution method. ResultsPneumococcal colonization rate among healthy children was 31.8% (143/450) it was 39.8% (179/450) in children hospitalized with respiratory symptoms. MIC for penicillin and cefotaxime ranged between 0.015 to 4 µg/ml and <0.015 to 16 µg/ml respectively. All isolates were susceptible to levofloxacin, vancomycin, linezolid and rifampicin. Erythromycin and tetracycline non-susceptibility rates were >50% in both groups. The predominant serotypes identified were 19F (n = 66, 20.5%), 6B (n = 43, 13.4%), 6A (n = 30, 9.3%), 23F (n = 28, 8.7%) and 14 (n = 20, 6.2%). Among healthy children, presence of school going children at home and the number of household members were significantly associated with pneumococcal colonization while in hospitalized children, pneumococcal colonization was significantly associated with presence of school going children at home. ConclusionPneumococcal colonization rates were considerably higher in both study cohorts and the commonest serotypes were 19F, 6B, 6A, 23F and 14. Antibiotic resistance rates were also relatively higher among the pneumococcal isolates.

Nasopharyngeal Colonization and levofloxacin Susceptibility of Streptococcus pneumoniae among Healthcare Workers in a Teaching Hospital in Tehran, Iran

Background: Streptococcus pneumoniae commonly asymptomatically colonizes the human upper respiratory tract and the carriage rate varies between geographical regions. The colonized individuals are not only at risk of infections but also can be a source of transmission of the pathogen. The risk of the droplet or airborne transmission of pneumococcal strains healthcare workers is considerable. The current study aimed to determine the extent of nasopharyngeal colonization with S. pneumoniae and their levofloxacin susceptibility at a tertiary hospital in Tehran, Iran. Materials and Methods: During a six-month period, the nasopharyngeal swab samples collected from 300 volunteer healthcare workers of Imam Hossein Hospital. Samples screened for S. pneumoniae using standard conventional biochemical methods. The minimum inhibitory concentration (MIC) of levofloxacin was determined using a commercially available strip antibiotic test according to the clinical laboratory standards institute (CLSI) guidelines. Results: A total of 19 (6.3%) enrolled healthcare workers were colonized with S. pneumoniae. Amongst the enrolled volunteers, nurses had a higher rate of pneumococcal colonization (47.3%) followed by interns (21%) and laboratory workers (15.8%). Our analysis revealed that there was a significant correlation between smoking and pneumococcal colonization. The antimicrobial susceptibility testing showed that all of the isolates were susceptible to levofloxacin (MIC≤2 μg/ml). Conclusion: This low rate of pneumococcal colonization amongst healthcare professionals may be attributed to the low risk of horizontal transmission of severe pneumococcal infections in the hospital. Additionally, our findings indicated that levofloxacin was an effective antimicrobial agent for the treatment of pneumococcal infections.

Role of antibodies and IL17-mediated immunity in protection against pneumococcal otitis media

Widespread vaccination against Streptococcus pneumoniae (the pneumococcus) has significantly reduced pneumococcal disease caused by vaccine serotypes. Despite vaccination, overall pneumococcal colonization rates in children have not reduced and otitis media (OM) by non-vaccine serotypes remains one of the most common childhood infections. Pneumococcal surface protein A (PspA) has been shown to be a promising protein antigen to induce broad protection against pneumococcal colonization. However, its ability to protect against OM remains unclear. Using our previously established mouse model of influenza-virus induced pneumococcal OM, we here show that intranasal vaccination of mice with PspA together with the mucosal adjuvant CTB results in a decrease in pneumococcal load in the middle ears. This decrease correlated with the induction of PspA-specific IgA, a balanced IgG1:IgG2a antibody response and the induction of a mucosal Th17 response. Our data suggests that the IL-17 response to PspA is more important for protection against OM, whilst the presence of antibodies may be less important, as determined in mice deficient in IL-17 signaling or antibody production. Together, these results suggest that mucosal vaccination with PspA may not only protect against colonization, but also against the development of virus-induced pneumococcal OM.

Nasopharyngeal Colonization With Pneumococci in HIV-Infected Adults Following the Introduction of Pneumococcal Conjugate Vaccine-13 in Children

1. Rodriguez-Barradas MC, et al. Colonization by Streptococcus pneumoniae among human immunodeficiency virus-infected adults. JID. 1997; 175:590-7. 2. Janoff EN, et al. Streptococcus pneumoniae colonization, bacteremia, and immune response among persons with human immunodeficiency virus infection. JID.1993; 167: 49-56. Background: Before widespread use of pneumococcal conjugate vaccine (PCV) in children, 14-20% of HIV-infected adults were colonized with pneumococci. We characterized nasopharyngeal pneumococcal colonization among HIV-infected adults following the introduction of PCV-13. Methods: HIV-infected adults seeking care at the Designated AIDS Center in Syracuse, NY between December 2013 and March 2015 were eligible. Following informed consent, an NP sample was collected, and patient demographics, medical and social history including risk factors for invasive pneumococcal disease (IPD) recorded. Pneumococci were identified from the samples using standard microbiologic techniques. Results: 707 nasopharyngeal samples were collected from 414 HIVinfected adults; 301 (73%) were males. Mean and median ages were 46.3 and 48 years, respectively. 391 (94%) and 42 (10%) were taking anti-retroviral therapy and sulfamethoxazole/trimethoprim prophylaxis, respectively. In addition to HIV infection, 210 (51%) had another co-morbidity placing them at increased risk for IPD. 12 (3%) had received PCV-13 and 220 (53%) had received pneumococcal polysaccharide vaccine-23 as recommended. Pneumococcus was isolated from 18/707 (2.5%) of samples and from 15/414 (3.6%) of patients. Colonization status was not associated with gender, race, co-morbidities, antibiotic use, smoking, alcohol use, intravenous drug use, children in the household, vaccine status, absolute neutrophil count, CD4 count, or viral load, however, colonized adults were more likely to have respiratory symptoms than those who were not colonized (46% vs 27%, p=0.02). Conclusion: Current pneumococcal colonization rates in HIV-infected adults are below historical rates suggesting reduction due to the widespread use of PCV-13. When present, colonization may be associated with respiratory symptoms.

Impact of experimental human pneumococcal carriage on nasopharyngeal bacterial densities in healthy adults.

Colonization of the nasopharynx by Streptococcus pneumoniae is a necessary precursor to pneumococcal diseases that result in morbidity and mortality worldwide. The nasopharynx is also host to other bacterial species, including the common pathogens Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis. To better understand how these bacteria change in relation to pneumococcal colonization, we used species-specific quantitative PCR to examine bacterial densities in 52 subjects 7 days before, and 2, 7, and 14 days after controlled inoculation of healthy human adults with S. pneumoniae serotype 6B. Overall, 33 (63%) of subjects carried S. pneumoniae post-inoculation. The baseline presence and density of S. aureus, H. influenzae, and M. catarrhalis were not statistically associated with likelihood of successful pneumococcal colonization at this study’s sample size, although a lower rate of pneumococcal colonization in the presence of S. aureus (7/14) was seen compared to that in the presence of H. influenzae (12/16). Among subjects colonized with pneumococci, the number also carrying either H. influenzae or S. aureus fell during the study and at 14 days post-inoculation, the proportion carrying S. aureus was significantly lower among those who were colonized with S. pneumoniae (p = 0.008) compared to non-colonized subjects. These data on bacterial associations are the first to be reported surrounding experimental human pneumococcal colonization and show that co-colonizing effects are likely subtle rather than absolute.

Impact of 13-Valent Pneumococcal Conjugate Vaccination on Streptococcus pneumoniae Carriage in Young Children in Massachusetts

In April 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 for use in the United States. We evaluated rates of pneumococcal colonization, by serotype and antibiotic resistance, in Massachusetts communities where serial cross-sectional surveillance has been conducted for the past decade. Nasopharyngeal swabs were obtained from children 0 to <7 years of age and seen by primary care providers for well child or acute illness visits in 2001, 2004, 2007, 2009, and 2011. Pneumococcal isolates were serotyped by Quellung reaction and classified as PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, 23F), additional PCV13 serotypes (1, 3, 5, 6A, 7F, 19A), or non-PCV13 serotypes. Changes in colonization and impact of PCV13 were assessed using generalized linear mixed models, adjusting for known risk factors and accounting for clustering by community. Introduction of PCV13 did not affect the rate of overall pneumococcal colonization (31% in 2011). Colonization with non-PCV13 serotypes increased between 2001 and 2011 for all children (odds ratio [OR] per year, 1.12; 95% confidence interval [CI], 1.10, 1.15; P < .0001). 19A remained the second most common serotype in 2011, although a decline from 2009 was observed. Penicillin (7%), erythromycin (28%), ceftriaxone (10%), and clindamycin (10%) nonsusceptibility were commonly identified, concentrated among a small number of serotypes (including 19A, 35B, 15B/C, and 15A). Among healthy children 6-23 months old, colonization with PCV13 serotypes was lower among recipients of PCV13 vaccine (adjusted OR, 0.30; 95% CI, 0.11, 0.78). This effect was not observed in 6- to 23-month-old children with a concomitant respiratory tract infection (adjusted OR 1.36; 95% CI, 0.66, 2.77) or children 2 to <7 years old (adjusted OR, 1.17; 95% CI, 0.58, 2.34). 13-Valent pneumococcal conjugate vaccine reduced the prevalence of colonization with PCV13 serotypes among children 6-23 months old, but its efficacy was not shown among older children.

Interactions Between Streptococcus Pneumoniae and Influenza Virus: A Mutually Beneficial Relationship?

Historically, most research on infectious diseases has focused on infections with single pathogens. However, infections with pathogens often occur in the context of pre-existing viral and bacterial infections. Clinically, this is of particular relevance for coinfections with Streptococcus pneumoniae and influenza virus, which together are an important cause of global morbidity and mortality. In recent years new evidence has emerged regarding the underlying mechanisms of influenza virus-induced susceptibility to secondary pneumococcal infections, in particular regarding the sustained suppression of innate recognition of S. pneumoniae. Conversely, it is also increasingly being recognized that there is not a unidirectional effect of the virus on S. pneumoniae, but that asymptomatic pneumococcal carriage may also affect subsequent influenza virus infection and the clinical outcome. Here, we will review both aspects of pneumococcal influenza virus infection, with a particular focus on the age-related differences in pneumococcal colonization rates and invasive pneumococcal disease.

Increasing antibiotic resistance in Streptococcus pneumoniae colonizing children attending day‐care centres in Singapore

Streptococcus pneumoniae is an important cause of morbidity and mortality in both the paediatric and adult population. This study aimed to define pneumococcal colonization rates, and antibiotic resistance patterns across two periods a decade apart, and also assess the serotypes of colonizing strains in children in the era of early pneumococcal conjugate vaccine uptake in Singapore. Two cross-sectional prevalence surveys were carried out in 1997 and 2007-2008 on children attending day-care centres across Singapore. Nasopharyngeal swabs were obtained and cultured for S. pneumoniae, and antibiotic susceptibility testing was performed. Serotyping was also done in the 2007-2008 survey. Three hundred and ninety-five children participated in the first survey in 1997, and 418 in the 2007-2008 survey. Pneumococcal colonization rates were 25.8 and 14.1%, respectively. There was a marked increase in antimicrobial non-susceptibility (penicillin 27.4% vs 69.5%; erythromycin 33.4% vs 78%; clindamycin 24.5% vs 45.8%, tetracycline 48% vs 67.8%), and multi-drug resistance (defined as non-susceptibility to three or more classes of antibiotics) increased from 33.3 to 74.6%. In the 2007-2008 survey, serotypes 6B (16.9%), 23F (11.9%) and 19F (10.2%) were most commonly observed. The projected coverage of the 7 and 13-valent conjugate pneumococcal vaccine for colonizing serotypes were 61.9 and 67%, respectively. S. pneumoniae antibiotic resistance has risen dramatically over the last 10 years in Singapore. Wider conjugate vaccine uptake and improved antibiotic stewardship should be made priorities. Surveillance of sentinel sites like day-care centres provides important data with respect to shifts in pneumococcal ecology.

Effect of presumptive co-trimoxazole prophylaxis on pneumococcal colonization rates, seroepidemiology and antibiotic resistance in Zambian infants: a longitudinal cohort study

To ascertain the microbiological consequences of WHO's recommendation for presumptive co-trimoxazole prophylaxis for infants with perinatal HIV exposure. Using a longitudinal cohort design, we followed HIV-exposed and HIV-unexposed infants trimonthly for up to 18 months per infant. HIV-exposed infants received daily co-trimoxazole prophylaxis from 6 weeks to > or = 12 months of age. Using Streptococcus pneumoniae as our sentinel pathogen, we measured how co-trimoxazole altered nasopharyngeal colonization, pneumococcal resistance to antibiotics and serotype distribution as a function of co-trimoxazole exposure. From 260 infants followed for 3096 patient-months, we detected pneumococci in 360/1394 (25.8%) samples. HIV-exposed infants were colonized more frequently than HIV-unexposed infants (risk ratio, RR: 1.4; 95% confidence interval, CI: 1.0-1.9, P = 0.04). Co-trimoxazole prophylaxis reduced colonization by ca 7% but increased the risk of colonization with co-trimoxazole-resistant pneumococci within 6 weeks of starting prophylaxis (RR: 3.2; 95% CI: 1.3-7.8, P = 0.04). Prophylaxis with co-trimoxazole led to a small but statistically significant increase of nasopharyngeal colonization with pneumococci not susceptible to clindamycin (RR: 1.6; 95% CI: 1.0-2.6, P = 0.04) but did not increase the risk of non-susceptibility to penicillin (RR: 1.1; 95% CI: 0.7-1.7), erythromycin (RR: 1.0; 95% CI: 0.6-1.7), tetracycline (RR: 0.9; 95% CI: 0.6-1.5) or chloramphenicol (RR: 0.8; 95% CI: 0.3-2.3). Co-trimoxazole prophylaxis did not cause the prevailing pneumococcal serotypes to differ from those that are targeted by the 7-valent conjugate pneumococcal vaccine (RR: 1.0; 95% CI: 0.7-1.6). Co-trimoxazole prophylaxis modestly suppresses pneumococcal colonization but accelerates infant acquisition of co-trimoxazole- and clindamycin-resistant pneumococci. Co-trimoxazole prophylaxis appears unlikely to compromise the future efficacy of conjugate vaccines.

Vaccination antipneumococcique : bénéfices attendus chez l'adulte

Purpose Streptococcus pneumoniae is one of the leading causes of bacterial pneumonia, meningitis and acute otitis media in children and adults worldwide. Polysaccharide pneumococcal vaccines have been available for approximately 50 years and conjugate vaccines, which generate immunological memory even at an early age but have limited serotype coverage, have recently been developed. Current knowledge and key points Although the polysaccharide vaccine is considered effective in preventing invasive pneumococcal disease (IPD) in adults, its efficacy against pneumonia and among older or immunocompromised individuals is still controversial. On the other hand, the conjugate vaccine for children allows a large reduction in the incidence of IPD and in the rate of pneumococcal colonization in the general population through herd immunity, but its serotype coverage remains low in adults and serotype replacement may be expected in the long-term. Future prospects In the present context of widespread antibiotic resistance, it is of the utmost importance to assess the expected benefits of pneumococcal vaccination, in order to be able to use it optimally in all population parts.

Pneumococcal Colonization and Antibiotic Resistance

Patients with HIV infection have about a 100-fold increased risk of invasive pneumococcal infection. Because the development of clinical disease depends in part on the frequency of carriage of invasive serotypes, these Houston researchers determined pneumococcal colonization rates of adults with HIV at a variety of different CD4-cell counts and compared this rate with noninfected controls. Researchers recruited 103 HIV-infected patients and …

Colonization with antibiotic-resistant Streptococcus pneumoniae in children with sickle cell disease

OBJECTIVE: Because of a susceptibility to severe pneumococcal infection, children with sickle cell disease (SCD) routinely receive penicillin prophylaxis. Increasing rates of penicillin resistance have been reported throughout the world. Our objective was to assess the prevalence of nasopharyngeal colonization with Streptococcus pneumoniae and to assess the antimicrobial susceptibility of the organisms in children with SCD. STUDY DESIGN: Nasopharyngeal cultures for S. pneumoniae were obtained from all children with SCD attending clinics in a statewide university-based network. Background colonization rates were determined in children attending day care centers in some of the same locations. All recovered S. pneumoniae organisms were tested for susceptibility to penicillin, and all resistant strains were examined for susceptibility to other antibiotics. RESULTS: Overall nasopharyngeal pneumococcal colonization rates among children with SCD were 12%. Colonization was associated with age less than 2 years ( p <0.001) and day care attendance for more than 20 hr/wk ( p = 0.00005). More than half of these strains (62%) were resistant to penicillin, 33% having intermediate resistance (minimal inhibitory concentration 0.06 to 1 μg/ml) and 29%, high level resistance (minimal inhibitory concentration ≥2.0 μg/ml). Penicillin resistance was associated with penicillin prophylaxis ( p <0.01). Many of these organisms were also resistant to other classes of antibiotics. CONCLUSIONS: Although penicillin prophylaxis and pneumococcal vaccine for patients with SCD have reduced overall nasopharyngeal colonization and disease caused by S. pneumoniae ( p <0.001), a higher percentage of colonizing strains are now resistant both to penicillin and to other antimicrobial agents ( p <0.01). Newer strategies for preventing disease and early management of suspected pneumococcal infection in these children must be developed. (J P EDIATR 1996; 128:531-5)