Nasopharyngeal vs. adenoid cultures in children undergoing adenoidectomy: prevalence of bacterial pathogens, their interactions and risk factors

The Molecular Epidemiology of Pneumococcal Strains Isolated from the Nasopharynx of Preschool Children 3 Years after the Introduction of the PCV Vaccination Program in Poland

The genetic mechanisms of resistance, clonal composition, and the occurrence of pili were analyzed in 39 pneumococcal strains isolated from healthy children in the southeastern region of Poland. Strains with resistance to combinations of erythromycin, clindamycin, and tetracycline were found in clonal groups (CGs) related to Tennessee 23F-4 and Taiwan 19F-14 clones. Capsular switching possibly occurred in the Spain 9V-3 clone and its variants to serotypes 35B and 6A, as well as DLVs of Tennessee 23F-4 to serotype 23A. The double-locus variants of Colombia 23F-26 presented serotype 23B. The major transposons carrying the erythromycin and tetracycline resistance genes were Tn6002 (66.6%), followed by Tn916 (22.2%) and Tn2009 (11.1%). The macrolide efflux genetic assembly (MEGA) element was found in 41.7% of all erythromycin-resistant isolates. The majority of the isolates carrying the PI-1 gene belonged to the CGs related to the Spain 9V-3 clone expressing serotypes 35B and 6A, and the presence of both PI-1 and PI-2 was identified in CG4 consisting of the isolates related to the Taiwan 19F-14 clone expressing serotypes 19F and 19A. Importantly, in the nearest future, the piliated strains of serogroups 23B, 23A, and 35B may be of concern, being a possible origin of the emerging clones of piliated non-vaccine pneumococcal serotypes in Poland. This study reveals that nasopharyngeal carriage in children is an important reservoir for the selection and spreading of new drug-resistant pneumococcal clones in the community after the elimination of vaccine serotypes.

Risk factors and antibiotic sensitivity of aerobic bacteria in Chinese children with adenoid hypertrophy

BACKGROUND

Bacterial infection of adenoid is currently considered to be an important cause of adenoid hypertrophy (AH) in children. Although several bacteriology studies on adenoid diseases have been reported, the aerobic bacterial study regarding risk factors and antibiotic sensitivity of AH in Chinese children is lacking. This study aims to investigate the risk factors for aerobic bacterial colonization of AH in Chinese children and to elucidate aerobic bacterial profiles and antibiotic sensitivity.

METHODS

Samples were collected from the adenoid core and surface tissue of 466 children undergoing adenoidectomy. Aerobic cultures and antibiotic sensitivity were observed. The risk factors for bacterial colonization of adenoid were analyzed statistically.

RESULTS

A total of 143 children could be detected opportunistic pathogens in adenoid surface and/or core tissue, with a carriage rate of 30.7%. The presence of chronic rhinosinusitis, tonsillar hypertrophy and adenoidal size were the risk factors for aerobic bacterial colonization of adenoid in univariate analysis. Multivariate analysis showed that chronic rhinosinusitis and tonsil hypertrophy were significant variables associated with the aerobic bacterial colonization. The most frequently isolated aerobic bacteria were Haemophilus influenzae, followed by Staphylococcus aureus and Streptococcus pneumoniae. There was no statistically significant difference in bacterial species between the adenoid surface and core. The above common bacteria were more sensitive to cephalosporins and quinolones antibiotics, and significantly resistant to penicillin antibiotics and non-β-lactamase inhibitors.

CONCLUSION

Our results provide recent aerobic bacterial profiles for AH among Chinese children and confirm the risk factors and antibiotic sensitivity. This study contributes to understanding the role of different risk factors in the development of AH and will be helpful to the treatment of AH among Chinese children.

Impact of Pneumococcal Vaccination on Nasopharyngeal Carriage of Streptococcus pneumoniae and Microbiota Profiles in Preschool Children in South East Poland

In 2017, Poland introduced the 10-valent pneumococcal conjugate vaccine (PCV) into its national immunization schedule. This prospective study was conducted between March and June 2020 to determine the impact of vaccination on prevalence of the nasopharyngeal carriage of S. pneumoniae in 176 healthy children and to determine how conjugate vaccines indirectly affect colonization of nasopharyngeal microbiota. Pneumococcal isolates were analyzed by serotyping and antimicrobial resistance tests. Nasopharyngeal microbiota were detected and identified using the culture method and real-time PCR amplification primers and hydrolysis-probe detection with the 16S rRNA gene as the target. In the vaccinated group of children, colonization was in 24.2% of children, compared to 21.4% in the unvaccinated group. Serotypes 23A and 23B constituted 41.5% of the isolates. Serotypes belonging to PCV10 and PCV13 constituted 4.9% and 17.1% of the isolates, respectively. S. pneumoniae isolates were resistant to penicillin (34.1%), erythromycin (31.7%), and co-trimoxazole (26.8%). Microbial DNA qPCR array correlated to increased amounts of Streptococcus mitis and S. sanguinis in vaccinated children, with reduced amounts of C. pseudodiphtericum, S. aureus, and M. catarrhalis. Introduction of PCV for routine infant immunization was associated with significant reductions in nasopharyngeal carriage of PCV serotypes and resistant strains amongst vaccine serotypes, yet carriage of non-PCV serotypes increased modestly, particularly serotype 23B.

Otopathogen interactions in the nasopharynx of children, and the predictive value of nasopharyngeal aspirate culture for the aetiology of upper respiratory infections

AIM

To evaluate nasopharyngeal aspirate cultures for screening otopathogen carriage in the adenoid in children 2-7 years of age.

METHODS

Thirty-seven children, 2-7 years of age, scheduled for adenoidectomy were enrolled into this prospective study at Rockhampton, Australia. Adenoid biopsy and nasopharyngeal aspirate bacteriology were assessed by conventional culture. Demographic and environmental data were collected by questionnaire. Statistical analyses for descriptive, comparison and logistic regression tests between microbial, demographic, environmental and clinical groups were applied.

RESULTS

Streptococcus pneumoniae, Staphylococcus aureus, non-typeable Haemophilus influenzae and Moraxella catarrhalis were detected in 38, 38, 35 and 24% of cases, respectively. Streptococcus pneumoniae was an independent determinant for non-typeable H. influenzae and S. aureus colonisation, and S. aureus was an independent determinant for S. pneumoniae colonisation. The nasopharyngeal aspirate otopathogen cultures were strong predictors for otopathogens in the adenoid, with moderate-high test accuracy for all otopathogens (receiver operator characteristics area under the curve ranging from 71 to 97% for the otopathogens tested). Children with positive non-typeable H. influenzae, M. catarrhalis, S. pneumoniae and S. aureus nasopharyngeal aspirate cultures were more likely to have the equivalent species in adenoid cultures (positive likelihood ratios = undefined, 15.0, 9.09 and 5.85, respectively).

CONCLUSIONS

This study provides evidence that nasopharyngeal aspirate cultures are an indicator of otopathogens in the adenoid. Nasopharyngeal aspirate cultures may provide clinicians with information that informs clinical management. Strategies for improved management to reduce otopathogen carriage could reduce the prevalence of chronic upper respiratory infections that contribute to adenoidectomy.

Molecular Epidemiology of Streptococcus pneumoniae Isolates from Children with Recurrent Upper Respiratory Tract Infections

A total of 125 isolates were recovered from adenoids and/or nasopharynx of 170 children aged 2 to 5 from south-east Poland; they had undergone adenoidectomy for recurrent and/or persistent symptoms of upper respiratory tract infections. Pneumococcal isolates were analyzed by phenotyping (serotyping and antimicrobial resistance tests) and genotyping together with the clonality of the pneumococcal isolates based on resistance determinants, transposon distribution and multilocus sequence typing (MLST). Serotypes 19F, 6B and 23F constituted 44.8% of the isolates. Among all of the strains, 44.8% showed decreased susceptibility to penicillin and resistance to co-trimoxazole (52.8%), tetracycline (38.4%), erythromycin (53.6%), clindamycin (52.8%) and chloramphenicol (27.2%) was observed. Tn6002 was found in 34.8% of erythromycin-resistant isolates while composite Tn2010—in 16.7% of erm(B)-carrying isolates that harboured also mef(E) gene. Tn3872-related elements were detected in 27.3% of erythromycin-resistant strains. In the majority of chloramphenicol-resistant cat_pC194-carrying isolates (79.4%), ICESp23FST81-family elements were detected. The genotyping showed that pneumococcal population was very heterogeneous; 82 sequence types (STs) were identified, and the most frequent contributed to not more than 8% of the isolates. Nearly 44% STs were novel, each of them was recovered only from one child. Four STs belonged to one of the 43 worldwide spread resistant pneumococcal clones currently accepted by Pneumococcal Molecular Epidemiology Network (PMEN), i.e. Spain 9V-3, Spain 23F-1, Norway NT-42 and Poland 6B-20, accounting for 12 (16.7%) of the 75 nonususceptible isolates, and five STs were single-locus variants of PMEN resistant clones (England 14–9, Spain 9V-3, Spain 23F-1, Greece 21–30, Denmark 14–32), accounting 9 (12%) of nonsusceptible isolates. A few MDR clones belonging to 6B and 19F serotypes found among preschool children emphasizes rather the role of clonal dissemination of local strains in the community than international clones spreading in the increase of resistance among pneumococcal strains.

The microbiome of otitis media with effusion

OBJECTIVES/HYPOTHESIS

The adenoid pad has been considered a reservoir for bacteria in the pathogenesis of otitis media with effusion. This study aimed to characterize the middle ear microbiota in children with otitis media with effusion and establish whether a correlation exists between the middle ear and adenoid microbiota.

STUDY DESIGN

Prospective, controlled study.

METHODS

Middle ear aspirates adenoid pad swabs were collected from 23 children undergoing ventilation tube insertion. Adenoid swabs from patients without ear disease were controls. Samples were analyzed using 16S rRNA sequencing on the Illumina MiSeq platform.

RESULTS

Thirty-five middle ear samples were collected. The middle ear effusion microbiota was dominated by Alloiococcus otitidis (23% mean relative abundance), Haemophilus (22%), Moraxella (5%), and Streptococcus (5%). Alloiococcus shared an inverse correlation with Haemophilus (P = .049) and was found in greater relative abundance in unilateral effusion (P = .004). The microbiota of bilateral effusions from the same patient were similar (P < .001). However, the otitis media with effusion microbiota were found to be dissimilar to that of the adenoid (P = .01), whereas the adenoid microbiota of otitis media with effusion and control patients were similar (P > .05) (permutational multivariate analysis of the variance).

CONCLUSIONS

Dissimilarities between the local microbiota of the adenoid and the middle ear question the theory that the adenoid pad is a significant reservoir to the middle ear in children with otitis media with effusion. A otitidis had the greatest cumulative relative abundance, particularly in unilateral effusions, and shares an inverse correlation with the relative abundance of Haemophilus.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:2844-2851, 2016.

Nasopharyngeal and Adenoid Colonization by Haemophilus influenzae and Haemophilus parainfluenzae in Children Undergoing Adenoidectomy and the Ability of Bacterial Isolates to Biofilm Production

Haemophili are pathogenic or opportunistic bacteria often colonizing the upper respiratory tract mucosa. The prevalence of Haemophilus influenzae (with serotypes distribution), and H. parainfluenzae in the nasopharynx and/or the adenoid core in children with recurrent pharyngotonsillitis undergoing adenoidectomy was assessed. Haemophili isolates were investigated for their ability to biofilm production.Nasopharyngeal swabs and the adenoid core were collected from 164 children who underwent adenoidectomy (2-5 years old). Bacteria were identified by the standard methods. Serotyping of H. influenzae was performed using polyclonal and monoclonal antisera. Biofilm formation was detected spectrophotometrically using 96-well microplates and 0.1% crystal violet.Ninety seven percent (159/164) children who underwent adenoidectomy were colonized by Haemophilus spp. The adenoid core was colonized in 99.4% (158/159) children, whereas the nasopharynx in 47.2% (75/159) children (P < 0.0001). In 32% (51/159) children only encapsulated (typeable) isolates of H. influenzae were identified, in 22.6% (36/159) children only (nonencapsulated) H. influenzae NTHi (nonencapsulated) isolates were present, whereas 7.5% (12/159) children were colonized by both types. 14.5% (23/159) children were colonized by untypeable (rough) H. influenzae. In 22% (35/159) children H. influenzae serotype d was isolated. Totally, 192 isolates of H. influenzae, 96 isolates of H. parainfluenzae and 14 isolates of other Haemophilus spp. were selected. In 20.1% (32/159) children 2 or 3 phenotypically different isolates of the same species (H. influenzae or H. parainfluenzae) or serotypes (H. influenzae) were identified in 1 child. 67.2% (129/192) isolates of H. influenzae, 56.3% (54/96) isolates of H. parainfluenzae and 85.7% (12/14) isolates of other Haemophilus spp. were positive for biofilm production. Statistically significant differences (P = 0.0029) among H. parainfluenzae biofilm producers and nonproducers in the adenoid core and the nasopharynx were detected.H. influenzae and H. parainfluenzae carriage rate was comparatively higher in the adenoid core than that in the nasopharynx in children undergoing adenoidectomy, suggesting that their involvement in chronic adenoiditis. The growth in the biofilm seems to be an important feature of haemophili colonizing the upper respiratory tract responsible for their persistence.