Incidence of Staph. Aureus in the Anterior Nares of Healthy Children

Although a good deal is known about the incidence of nasal carriage of Staphylococcus aureus in infants in maternity hospitals, little is known of the incidence in infants born at home or in infants after the first few weeks of life. The work described here is an attempt to fill this gap, and at the same time to determine the relation of nasal carriage in the infant to carriage in the mother. In the latter part of the investigation the penicillin sensitivity of the strains isolated was also tested and phage-typing was used in an attempt to solve certain problems. METHODSClinical material. Nasal swabbing was carried out in five Child Welfare Clinics on 530 infants aged 2 weeks to 2 years, although only a small number (57) were swabbed in their second year. The mothers of 488 of these infants were also swabbed. The clinics were visited at irregular intervals and most of the infants and mothers present at the time of the visit were swabbed. In addition to noting the age of the infant a record was kept of whether it had been born in hospital or at home. The sample of the mother-infant population examined may be regarded as representative of those who were regular attenders at the clinics. Examination of random samples of clinic records showed that a high proportion of the mothers were attending with their first or second child. As was to be expected, a higher proportion of the mothers delivered in hospital were primiparae than of those delivered at home.At the end of the investigation nasal swabs were also cultured from nurses and infants in maternity hospitals C and F and from the mothers of the infants in hospital C. Swabs of the floor dust from the two nurseries in hospital F were also cultured for Staph. aureus. In the course of another investigation the Health Department ophthalmic nurse sent in eye and nose swabs from infants born at home and suffering from neonatal eye infections. Nasal swabs were also taken from the mothers. As the results already obtained in this investigation are relevant to the present work they have been included here. This group is referred to hereafter as the 'special home group'.Cultural technique. The anterior nares and adjacent vestibule of each side were swabbed, and the swab was inoculated on to culture media less than 2 hr. after sampling. At the beginning of the investigation, in 1948-9, swabs were at first cultured in parallel on digest agar and a tellurite agar (Ludlam, 1949). As there appeared to be no significant difference in the results obtained with these two media, the tellurite agar was then used alone; the medium was found more useful for picking out scanty Staph. aureus colonies among numerous colonies of other

“…aureus in these infants was similar to that found by Cunliffe (1949). Cunliffe examined only a few infants born at home, but his figures suggested a low incidence.…”

Section: Discussionsupporting

confidence: 85%

Incidence and penicillin sensitivity ofStaphylococcus aureusin the nose in infants and their mothers

Ludlam¹

1953

“…The declining nasal carrier rate with increase in age is in accord with the observations of Cunliffe (1949) and Ludlam (1953), but that the throat carrier rate should remain at a high level was completely unexpected. This tendency for retention of hospital staphylococci in the throat after disappearance from the nose was especially evident in the babies' individual carrier records.…”

supporting

confidence: 78%

“…Obviously, if they carry them very long they may contribute greatly to the reservoir of penicillin-resistant strains in the general nonhospital population. The studies of Cunliffe (1949) and Ludlam (1953) indicate that the hospital strains often are eventually lost, for they found that babies aged 6 months to 2 years have low nasal carrier rates. However, Ludlam found that six of thirteen strains isolated from hospital-born babies at the age of 5-12 months were penicillin-resistant, suggesting that nursery-acquired staphylococci sometimes persist.…”

mentioning

confidence: 99%

Staphylococcus aureusin the infant upper respiratory tract: I. Observations on hospital-born babies

Hurst

1957

Pernasal and throat swabs taken on 106 newborn babies showed that 99% harboured coagulase-positiveStaph. aureusby the time they left the hospital nursery. When the strains isolated from thirty-four of them were phage typed and tested for penicillin sensitivity, it was found that thirty-three (97%) carried at least one penicillin-resistant strain. Phage typing of their subsequent cultures, taken as they became older, demonstrated that they retained these strains for very long periods. Of the twenty-one still under observation at 6 months of age, eleven (53%) were carrying one or more of their original hospital strains, and an additional three (14%) still were consistently yielding an untypable strain believed to be identical to that acquired in hospital. Similarly, of those remaining under observation for the last 6 months of their first year, at least 50% continued to carry their hospital strains.These babies frequently retained the hospital strains in their throats longer than in their noses. Although their nasal cultures often became negative after the first few months of life, the original hospital strains continued to be recovered from the throats. This would indicate that the throat culture is more accurate than the nasal culture in determining staphylococcal carriers among this age group. Antibiotic-resistant staphylococci in the infant throat may have considerable epidemiological significance, since babies tend to widely distribute their saliva.The observations suggest that the staphylococci acquired at birth become a normal component of the upper respiratory flora, and may thus prevent new strains of staphylococci from becoming established later. This may explain why newborn babies retain the antibiotic-resistant staphylococci of the hospital much longer than do adult patients. Antibiotic-resistant strains among the general non-hospital population will be increased steadily by babies born in hospitals.

“…In these cases 550 of the strains came from other mothers and 45 % from hospital staff. This was calculated as follows: (Cunliffe, 1949), who have observed carrier rates approaching 100 % at the end of the first week.…”

Section: Acquisition Of Strains By Mothers In Hospitalmentioning

confidence: 99%

“…As stated by Elek (1958), hospitals and maternity units provide the best opportunities for studies on this subject. Rountree & Barbour (1951) have shown the effect of the hospital environment on the nasal carriage of a group of nurses, while Cunliffe (1949) has studied the rapid rate of colonization of the anterior nares of infants in a maternity unit. Such units with antenatal and postnatal clinics provide a unique opportunity for more extended investigations involving both mother and child.…”

Section: Introductionmentioning

confidence: 99%

Staphylococcal nasal carriage in mothers, babies and staff in a maternity hospital

Anderson

Coulter

Keynes

1961

The nasal carriage of 407 mothers before, during and after admission to a maternity hospital and that of their babies during and after hospital stay was investigated together with the nasal carriage by the hospital staff.The nasal carrier rate among mothers admitted to hospital was 38%, 40% of these strains being resistant to penicillin.The nasal carrier rate among the nursing staff was 38 and 72% of these were resistant to penicillin.If a population is swabbed only once approximately 25% of the carriers will be missed. Those showing slight carriage were no more likely to be missed than those showing heavy carriage. The concentration of organisms in the nose is evidently varying continuously.Heavy carriers are no more likely to transmit than light carriers and it is therefore not right to report on the profusion or otherwise of growth if that implies a greater chance of transmission.The biggest increase in resistance among nursing staff strains occurred in the non-typable group which could be explained by resistance to phage developing concurrent with resistance to antibiotics.The difference in phage-distribution between patient and staff strains centred in group II which formed 19% of patient strains but only 7% of hospital strains.The carrier rate was no higher for those with a history of hospital admission within 12 months or without a history of staphylococcal sepsis.Those giving a history of penicillin therapy had the same resistance rate as those without a history of such therapy.