Antibodies to pneumococcal polysaccharides in human milk: lack of relationship to colonization and acute otitis media.

BACKGROUND: This study analyzed antibodies to pneumococcal polysaccharides in human milk and their effect on nasopharyngeal colonization and acute otitis media in breast-fed infants. METHODS: A total of 503 milk samples were collected from 310 mothers. Nasopharyngeal cultures were obtained from their children at 2, 6 and 10 months postpartum, and the capsular groups/types of the Streptococcus pneumoniae isolates were determined. RESULTS: Types 6A, 6B, 19A, 19F and 23F accounted for 54% of the pneumococcal isolates, but type 3 isolates were uncommon. Milk samples were analyzed for antibody activity to the common capsular polysaccharide types 6A, 19F and 23F; to the type 3 polysaccharide; to C-polysaccharide; and to phosphorylcholine (PC), a major component of the pneumococcal cell wall polysaccharide (CWPS). Anti-capsular antibody activity was low or absent in > 90% of the milk samples. In contrast anti-PC antibody activity was detected in 88% and anti-CWPS in 84% of the samples. The frequency of acute otitis media did not vary with the milk anti-capsular, anti-PC or anti-CWPS antibody activity. CONCLUSIONS: There was no reduction in nasopharyngeal carriage of S. pneumoniae among children fed milk with anti-capsular or anti-PC antibody activity, but carriage was increased in those children who received milk with anti-CWPS antibody activity. A protective role of antipolysaccharide or anti-CWPS antibodies in milk was not detected under the study conditions.

A prospective cohort study on breast-feeding and otitis media in Swedish infants.

This study analyzed the effect of breast-feeding on the frequency of acute otitis media. The protocol was designed to examine each child at 2, 6 and 10 months of age. At each visit nasopharyngeal cultures were obtained, the feeding pattern was recorded and the acute otitis media (AOM) episodes were documented. The analysis was based on 400 children from whom complete information was obtained. They represented 83% of the newborns in the study areas. By 1 year of age 85 (21%) children had experienced 111 AOM episodes; 63 (16%) had 1 and 22 (6%) had 2 or more episodes. The AOM frequency was significantly lower in the breast-fed than in the non-breast-fed children in each age group (P < 0.05). The first AOM episode occurred significantly earlier in children who were weaned before 6 months of age than in the remaining groups. The frequency of nasopharyngeal cultures positive for Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae was significantly higher in children with AOM. At 4 to 7 and 8 to 12 months of age, the AOM frequency was significantly higher in children with day-care contact and siblings (P < 0.05 and < 0.01, respectively). The frequency of upper respiratory tract infections was increased in children with AOM but significantly reduced in the breast-fed group.

Anti-adhesive activity of human casein against Streptococcus pneumoniae and Haemophilus influenzae.

The casein fraction of human milk was found to inhibit the attachment of Streptococcus pneumoniae and Haemophilus influenzae human respiratory tract epithelial cells. The inhibitory activity for S. pneumoniae remained after heat and trypsin treatment of the casein and was found in oligosaccharides released from casein. kappa-Casein, which is the most highly glycosylated casein component, inhibited pneumococcal attachment at concentrations similar to the whole casein fraction. The results are consistent with the known recognition of GlcNAc beta 1-3Gal by S. pneumoniae, since human milk and bovine colostrum, which contain GlcNAc, inhibited attachment, but mature bovine milk lacking GlcNAc did not. The effect on H. influenzae was similar to that on S. pneumoniae in that the attachment was inhibited by human casein and bovine colostrum, but not by either mature bovine milk or by the bovine casein fraction. The kappa-casein component of human milk was a less efficient inhibitor of H. influenzae attachment than the whole casein fraction and the free oligosaccharides were inactive. This anti-microbial effect of human casein represents a new mechanism for the protection by breast-milk against respiratory tract infection.

Hearing loss at age 7, 10 and 13--an audiometric follow-up study.

School children are regularly tested in Sweden at age 7, 10 and 13. We report the audiometric results of 2264 school children tested at these three ages. Audiometry was performed as hearing screening at 0.5, 1, 2, 4, 6, 8 kHz with a screening level of 20 dBHL. Unilateral hearing losses with one test frequency affected were most common and bilateral hearing losses were least common. The hearing loss was more common in boys than in girls at all ages. Hearing loss at 2 kHz in boys at age 7 were uncharged in most cases (13/17 boys still failing screening at age 13). High frequency losses were most common, particularly at age 10 and 13 and more prevalent in boys than in girls, suggesting early noise induced hearing loss as an etiology.

Hearing loss in school children. A longitudinal study of sensorineural hearing impairment.

In a longitudinal study, 2325 children were hearing tested at age 7, 10 and 13 with screening audiometry. The screening level was 20 dB HL. Approximately 75% of the children passed the screening level at all ages. Hearing loss was more frequent in boys than in girls at age 13 (16%:9%). The left ear was more commonly affected than the right ear. High frequency dips increased for boys with age, but not for girls. The increasing incidence of hearing loss for boys with age is probably due to noisy leisure time activities.

Spontaneous improvement in ears with middle ear disease.

The 'healthy-baby-clinics' in Göteborg, as in all Sweden, test all 4-year-olds with pure tone screening (failure criterion greater than 20 dB). Those who fail are referred to an oto-audiological health center. In an effort to prevent over-referrals of false positives as well as under-referrals of false negatives all referred children in this study have been tested with pure tone audiometry supplemented by tympanometry. At the oto-audiological health center a test program including 3 tests with intervals of 6 weeks was initiated. Failure criteria were middle ear pressure less than - 150 mm H2O and hearing loss (HL) in the frequency range 0.125-8 kHz greater than 20 dB. In Göteborg (430,000 inhabitants) 5928 4-year-olds were tested at the 'healthy-baby-clinics' during 1980. Of these 498 (8.4%) failed in pure tone screening, 248 of which are included in the present study. At the first check in our test program, which was performed 3-8 weeks after referral, only 45% of the children were abnormal. Of these 60% normalized during the test program. Thus of the ears referred following the pure tone screening at the 'healthy-baby-clinics' only 18% remained after 15-20 weeks for referral to an ENT-doctor.

Speech intelligibility in and speech interference levels of traffic noise in hearing-impaired and normal listeners.

Speech intelligibility (phonetically balanced monosyllables = PB words) in traffic-like noise (random noise) as well as the speech interference levels (75% intelligibility) of this noise were investigated in three common listening situations, two indoors and one outdoors. A total of 279 persons were examined; 56 had normal hearing, 90 a presbycusic-type hearing loss, 95 noise-induced hearing loss, and 38 conductive hearing loss. In the indoor situation the hearing-impaired groups mainly retained their intelligibility in 40 dBA. Lowering of the noise level to less than 40 dBA resulted in only a minor, mostly insignificant improvement in speech intelligibility. Normal-hearing listeners maintained good speech intelligibility in the outdoor listening situation with noise levels up to 60 dBA, without lip-reading. For hearing-impaired groups, representing more than 1/2 million (8% of the population) people in Sweden, with hearing loss due to age and/or noise, the noise level outdoors must be lowered to 45 dBA in order to achieve good speech intelligibility at 1 m, without lip-reading.