Nasopharyngeal carriage of Streptococcus pneumoniae in Finnish children younger than 2 years old

To describe the natural course of nasopharyngeal carriage of Streptococcus pneumoniae and its relationship to acute otitis media (AOM), 329 Finnish children were followed from ages 2 to 24 months. In total, 3024 nasopharyngeal (NP) swabs (obtained at 10 scheduled healthy visits) and 2007 NP aspirates (obtained during respiratory infections) were cultured. Carriage during health increased gradually (9%-43%) with age. Within 4 age intervals, carriage was lower during health (13%-43%) than during respiratory infection without AOM (22%-45%). Higher proportions of positive samples were found during AOM (45%-56%), in particular during pneumococcal AOM (97%-100%). Antimicrobial treatment reduced carriage only temporarily. The most frequent NP serotypes were 6B, 6A, 11, 19F, and 23F. Both age and health status were important determinants of NP carriage of S. pneumoniae and these features should be considered carefully during analysis of carriage rates.     

Nasopharyngeal carriage of S. pneumoniae among young children in rural Nepal

Objectives  To provide epidemiologic data on Streptococcus pneumoniae ( Spn ) carriage in Nepal.
Methods  Prospective, population-based study among children in Sarlahi, Nepal to estimate carriage prevalence, identify risk factors, and determine antibiotic susceptibility patterns and serotype distribution. Between December 2003 and July 2004, NP specimens were collected from 604 children aged 1–36 months with acute lower respiratory infection (ALRI) and 604 healthy, age- and season-matched controls.
Results  Of the 1100 specimens analysed, carriage prevalence was approximately 80% in both groups. In the multivariate analyses, significant risk factors for Spn carriage in controls were Muslim religion [adjusted odds ratio (AOR): 2.93] and no latrine in the household (AOR: 2.41). Those treated for a recent illness had lower carriage rates (AOR: 0.37). Results were similar for ALRI cases with the addition of age ≥12 months (AOR: 1.68), and symptomatic infection (AOR: 3.78) as risk factors. The antibiotics and proportions of isolates resistant to them were as follows: penicillin 4.5%, cotrimoxazole 89.2%, chloramphenicol 1.4%, erythromycin 1.5% and tetracycline 22.7%. The most prevalent serogroups/types were 6, 19, 23, 15, 9 and 10.
Conclusions  Young children in rural Nepal experience high rates of Spn carriage. Most isolates were resistant to cotrimoxazole. Current conjugate Spn vaccines may substantially reduce the risk of a severe pneumonia and other Spn infections.     

Molecular typing of Streptococcus pneumoniae in northeastern Romania: unique clones of S. pneumoniae isolated from children hospitalized for infections and from healthy and human immunodeficiency virus-infected children in the community

Microbiologic, serologic, and molecular typing techniques were used to characterize 272 isolates of Streptococcus pneumoniae colonizing or infecting children in Iasi, Romania, during a surveillance study conducted in 1996-1998. The 574 children in the study were from the following groups: healthy children attending 2 institutions, healthy children hospitalized for elective surgery, hospitalized children with pneumococcal infections, and human immunodeficiency virus (HIV)-infected children in an orphanage. Pneumococci colonizing healthy children from closed communities showed close similarities to pneumococci from children with pneumococcal infections; they expressed a limited number of similar serotypes, showed high frequency of penicillin and multidrug resistance, and shared several common clonal types. In contrast, isolates recovered from healthy children hospitalized for elective surgery expressed a large variety of serotypes, were less frequently resistant to antimicrobial agents, and showed great genetic diversity. Pneumococcal flora colonizing HIV-infected children showed a more complex epidemiology. These observations suggest a possible epidemiologic connection between the flora of S. pneumoniae colonizing healthy children in closed communities and the flora found in children hospitalized for infection.     

Streptococcus pneumoniae carriage and penicillin/ ceftriaxone resistance in hospitalised children in Darwin

Background: The prevalence of resistant Streptococcus pneumoniae (SP) is increasing worldwide. Pneumococcal prevalence and susceptibility patterns are not known for children in the Top End of the Northern Territory.
Aims: To determine the prevalence of nasopharyngeal carriage of pneumococci in children hospitalised in Darwin, and the extent of penicillin and ceftriaxone resistance in these isolates.
Methods: Nasopharyngeal swabs were collected on admission from 85 children who had not received antimicrobials for their admission illness. Antimicrobial resistance was determined following selective culture for SP isolates. Minimal inhibitory concentrations (MICs) for penicillin and ceftriaxone were determined using the E-test method.
Results: The overall prevalence of nasopharyngeal SP carriage was 44%. Carriage occurred more often in Aboriginal children from rural areas (56%) than in urban children (24%) (OR 3.94, 95% CI 1.35 - 11.78, p <0.01). Thirty per cent of isolates were penicillin resistant, 35% were ceftriaxone resistant, and 49% were resistant to at least one of these. One isolate showed high-level resistance to both antimicrobials; all other resistant isolates were of intermediate-level resistance. For the same isolate, MICs for ceftriaxone were more often higher than those for penicillin. Five isolates had intermediate resistance to ceftriaxone whilst remaining sensitive to penicillin.
Conclusions: The prevalence of pneumococcal resistance to penicillin and ceftriaxone in hospitalised children in Darwin is much higher than previously reported in Australia. This has implications for future antimicrobial management and highlights the need for regular regional surveillance of SP resistance. The development of conjugate pneumococcal vaccines for children under two years is a priority.     

The emergence of drug-resistant Streptococcus pneumoniae and host risk factors for carriage of drug-resistant genes in northeastern Japan

Our 2-year study includes research into the occurrence, molecular characteristics, and host risk factors for the carriage of drug-resistant strains of Streptococcus pneumoniae as a continuation of our previous report. From September 2001 to June 2003, strains of S. pneumoniae were isolated from the nasopharynx of children with respiratory tract infection in Soma General Hospital. Of the total of 949 strains, 761 (81%) had a decreased susceptibility to penicillin (MIC > 0.12 microg/ml), while 818 (86%) were resistant to erythromycin (MIC > 1 microg/ml) and 789 (83%) were resistant to clarithromycin (MIC > 1 microg/ml). More than half of the strains had decreased susceptibility to meropenem. Gene analysis of 226 randomly selected strains showed that 200 strains (88.5%) had one or more altered pbp genes and 191 strains (84.5%) had mef(A) and/or erm(B) genes. We reviewed the patient backgrounds for previous antibiotic use, age, daycare attendance, and siblings. Previous use of oral beta-lactams has shown a strong relationship with the carriage of altered pbp genes (P value < 0.01), and previous oral macrolide use has been related to the carriage of macrolide-resistant genes (P value < 0.01). The controlled use of antibiotics might be an important factor in preventing the emergence of S. pneumoniae with antibiotic-resistant genes.     

Evaluation of Streptococcus pneumoniae urinary antigen test in healthy children with nasopharyngeal pneumococcal carriage

We evaluated the influence of colonization with pneumococci on the results of Streptococcus pneumoniae urinary antigen detection assay by testing 23 healthy children aged 1-3 years in one nursery. Nasopharyngeal swab specimens for culture and urine samples for antigen detection test were obtained. 7 of 12 children who were nasopharyngeal carriers of pneumococci had a positive result of the urine antigen test. 3 of 11 children without pneumococci in the nasopharynx also had a positive result of the urine antigen test, who were diagnosed as having acute pneumonia within one month before this study. Thus we found that 58.3% of the children with pneumococcal carriage and 27.3% of non-carriers had false-positive test results. This test is not likely to be useful for diagnosing the etiology of childhood acute pneumococcal pneumonia.     

Capsular serotype-specific attack rates and duration of carriage of Streptococcus pneumoniae in a population of children

BACKGROUND: The relative invasiveness rates (attack rates) of Streptococcus pneumoniae of different capsular serotypes in children are not known. Estimates of capsular serotype invasiveness (designated "invasive odds ratios") that are based on cross-sectional prevalence carriage data have been published, but these estimates could be biased by variation in the duration of carriage. METHODS: The relative attack rates of invasive pneumococci were measured using national UK surveillance data on invasive pneumococcal disease (IPD) incidence and data on incidence of pneumococcal acquisition from longitudinal studies of nasopharyngeal pneumococcal carriage. RESULTS: We found significant differences in capsular serotype-specific attack rates. For example, capsular serotypes 4, 14, 7F, 9V, and 18C were associated with rates of >20 IPD cases/100,000 acquisitions, whereas capsular serotypes 23F, 6A, 19F, 16F, 6B, and 15B/C were associated with <10 IPD cases/100,000 acquisitions. There was an inverse relationship between duration of carriage and attack rate by capsular serotype (P<.0001). Attack rates were significantly correlated with invasive odds ratios (P<.0001). CONCLUSIONS: The capsular serotype is a major determinant of both pneumococcal duration of carriage and attack rate. Published invasive odds ratios are a reliable and practical method of determining capsular serotype invasiveness and will be valuable for investigating and characterizing emerging capsular serotypes in the context of conjugate vaccination.     

Nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Alloiococcus otitidis in young children in the era of pneumococcal immunization, Taiwan

We applied a multiplex polymerase chain reaction (PCR) and culture to detect Streptococcus pneumoniae and detected 3 other respiratory pathogens--Haemophilus influenzae, Moraxella catarrhalis, and Alloiococcus otitidis--simultaneously by PCR, in the nasopharynx of 386 children aged under 5 y. S. pneumoniae was the most common pathogen carried by children in all age groups, with the rate ranging from 15.8% in children aged 3-4 y to 28.6% in children aged 2-3 y. H. influenzae and M. catarrhalis showed similar carriage rates across all the age groups. Only 2 young children (0.5%) carried A. otitidis. Higher carriage of S. pneumoniae was found in children who had not received the heptavalent pneumococcal conjugate vaccine (PCV7). Cefotaxime non-susceptibility was high (51.4%) in S. pneumoniae nasopharyngeal isolates. Serotype 6B was the most common in fully immunized carriers and also in those who received catch-up immunization. Due to low PCV7 coverage in Taiwan, the carriage of vaccine and non-vaccine serotypes of S. pneumoniae in children remains common.     

Streptococcus pneumoniae and Legionella pneumophila pneumonia in HIV-infected patients

We compared the epidemiological data, clinical features and mortality of community-acquired pneumonia (CAP) by Streptococcus pneumoniae and Legionella in HIV-infected patients and determined discriminative features. An observational, comparative study was performed (January 1994 to December 2004) in 15 HIV patients with CAP by Legionella and 46 by S. pneumoniae. No significant differences were observed in delay until initiation of appropriate antibiotic therapy. Smoking, cancer and chemotherapy were more frequent in patients with Legionella pneumonia (p=0.03, p=0.00009 and p=0.01). Patients with Legionella pneumonia had a higher mean CD4 count (p=0.04), undetectable viral load (p=0.01) and received highly active antiretroviral therapy more frequently (p=0.004). AIDS was more frequent in patients with S. pneumoniae pneumonia (p=0.03). Legionella pneumonia was more severe (p=0.007). Extrarespiratory symptoms, hyponatraemia and increased creatine phosphokinase were more frequent in Legionella pneumonia (p=0.02, p=0.002 and p=0.006). Respiratory failure, need for ventilation and bilateral chest X-ray involvement were of note in the Legionella group (p=0.003, p=0.002 and p=0.002). Mortality tended to be higher in the Legionella group (6.7 vs 2.2%). In conclusion, CAP by Legionella has a higher morbimortality than CAP by S. pneumoniae in HIV-infected patients. Detailed analysis of CAP presentation features allows suspicion of Legionnaires' disease in this subset.     

Clones of Streptococcus pneumoniae isolated from nasopharyngeal carriage and invasive disease in young children in central Tennessee

To determine whether nasopharyngeal carriage isolates of Streptococcus pneumoniae are of the same genetic background as isolates that caused invasive disease in one community, IS1167 and boxA genotypes were obtained for 182 pneumococcal isolates from children living in central Tennessee. The isolates represented 70 combined IS1167-boxA genotypes. The genotypic diversity of the invasive isolates was significantly less than that of the total population (P=.003). Most of the carriage isolates belonged to genotypes unique to carriage, whereas most of the invasive isolates belonged to genotypes common to carriage and disease (P=.02). Monte Carlo simulations showed a greater number of genotypes unique to carriage than can be explained by chance (P<.05 in all cases). Two genotypes were identified by multilocus sequence typing as members of globally disseminated clones, and one such genotype that was strictly carriage in this sample caused disease in other studies. Thus, clones can have different propensities for carriage and invasion.     

Nutrition rehabilitation of HIV-infected and HIV-negative undernourished children utilizing spirulina

The objective of this study was to assess the impact of an alimentary integrator composed of spirulina (Spirulina platensis; SP), produced at the Centre Médical St Camille of Ouagadougou, Burkina Faso, on the nutritional status of undernourished HIV-infected and HIV-negative children. We compared two groups of children: 84 were HIV-infected and 86 were HIV-negative. The duration of the study was 8 weeks. Anthropometric and haematological parameters allowed us to appreciate both the nutritional and biological effect of SP supplement to traditional meals. Rehabilitation with SP shows on average a weight gain of 15 and 25 g/day in HIV-infected and HIV-negative children, respectively. The level of anaemia decreased during the study in all children, but recuperation was less efficient among HIV-infected children. In fact 81.8% of HIV-negative undernourished children recuperated as opposed to 63.6% of HIV-infected children (Z: 1.70 (95% CI -0.366, -0.002, p = 0.088)). Our results confirm that SP is a good food supplement for undernourished children. In particular, rehabilitation with SP also seems to correct anaemia and weight loss in HIV-infected children, and even more quickly in HIV-negative undernourished children.     

Independent risk factors for carriage of penicillin-non-susceptible Streptococcus pneumoniae

Antibiotic treatment, day-care center (DCC) attendance and young age are associated with penicillin-non-susceptible Streptococcus pneumoniae (PNSSp) carriage. Yet, it is unclear whether each is an independent risk factor for the individual. This cross-sectional surveillance study was designed to answer this question. Nasopharyngeal cultures were obtained from 429 children (< 6 y) during a visit to the pediatrician's office. Two risk rates were calculated: the individual's absolute risk to carry PNSSp [simple odds ratio (ORS)] and the risk of an individual who is already a carrier [conditional odds ratio (ORC)]. Streptococcus pneumoniae was isolated from 52.7% of 401 children. PNSSp was detected in 37.1% of carriers. Independent risk factors were: young age [ORS 2.24, 95% confidence interval (95% CI) 1.2-4.2], DCC attendance (ORS 3.8, 95% CI 1.9-7.5), having young siblings (ORS 2.3, 95% CI 0.95-5.57) and each antibiotic treatment during the previous 3 months (ORS 1.5, 95% CI 1.25-1.85). The only significant risk factor among carriers was prior antibiotic treatment (ORC 2.24, 95% CI 1.64-3.05). Young children, who attended DCC and received 1 antibiotic course (9% of the population) had a risk 12.9 times higher than children without these features.     

Nasopharyngeal carriage of Streptococcus pneumoniae at the completion of successful antibiotic treatment of acute otitis media predisposes to early clinical recurrence

OBJECTIVE: We sought to investigate the role of Streptococcus pneumoniae (SP) nasopharyngeal (NP) colonization after successful antibiotic treatment (Rx) of acute otitis media (AOM) in recurrent AOM (RAOM). PATIENTS AND METHODS: NP cultures were obtained from 494 (93%) of 530 patients at the end of antibiotic treatment (EOT). RESULTS: At enrollment, middle ear fluid (MEF) cultures in 418 (79%) of 530 patients were positive for pathogens. At EOT, NP cultures in 208 (42%) of 494 patients were positive for SP. RAOM was found in 130 (26%) of 494 patients: 66 (32%) of 208 with SP-positive NP and 64 of 286 (22%) without SP-positive NP at EOT (P=.026). MEF was positive for SP during RAOM in 34 (61%) of 56 patients with SP-positive NP and 17 (36%) of 47 patients without SP-positive NP at EOT (P=.022). The same serotype was identified in 24 (80%) of 30 SP pairs; complete identity was found between isolates in 22 (96%) of 23 SP pairs. CONCLUSIONS: Early RAOM was more commonly caused by SP if the organism was present in NP at EOT during the initial AOM episode. Most SP-RAOM episodes were caused by SP isolates present in NP at EOT during the previous AOM episode.     

Streptococcus pneumoniae nasopharyngeal carriage prevalence, serotype distribution, and resistance patterns among children on Lombok Island, Indonesia.

Few data exist on childhood pneumococcal carriage prevalence, serotype distribution, and resistance patterns for Indonesia, the world's fourth most populous country. During August 1997, nasopharyngeal samples were collected from a population-based, island-wide sample of 484 healthy children (age, 0-25 months) from Lombok Island, Indonesia. Two hundred twenty-one pneumococcal isolates were identified, for a carriage prevalence of 48%; 66% of isolates were of serogroup or serotype 6, 23, 15, 33, or 12. All isolates were susceptible to penicillin and cefotaxime. Twelve percent of the isolates were nonsusceptible to sulfamethoxazole or chloramphenicol and 4% were nonsusceptible to both of these drugs. Nonsusceptible organisms were most frequently serogroup or serotype 6, 12, and 33. Lombok has a moderate pneumococcal carriage prevalence and a relatively low proportion of resistant isolates. At least 3 of the 5 most common serogroups and serotypes and 2 of the 3 most common nonsusceptible serogroups and serotypes are not included in the current 7-valent pneumococcal conjugate vaccine.     

Asymptomatic pharyngeal carriage of Mycoplasma pneumoniae in Chilean children

PCR has become a sensitive option for the rapid detection of Mycoplasma pneumoniae in respiratory specimens, but little is known of the frequency of its asymptomatic carriage or persistence in the throat after Mycoplasma disease in healthy children. To investigate the frequency of asymptomatic carriage of M. pneumoniae in children, we studied by PCR throat specimens from 185 respiratory asymptomatic children aged 1-14 years, enrolled at two pediatric ambulatory health services of Santiago, Chile from September 2002 through August 2003. M. pneumoniae DNA was detected in 4 (2.16%) children. Positive specimens could represent either asymptomatic carriage or persistence of the organism from a previous disease.