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

Abstract

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

A prospective study of staphylococcal infection and its prevention among infants and mothers after childbirth in hospital and at home

“…There was no significant difference between the rates at 6 months, which by then K. G. BABER AND OTHERS had fallen to less than 30 % in all groups, in accordance with the findings of Ludlam (1953). The nasal carriage rates in all four groups of mothers were almost identical at the three times of swabbing (Table 7).…”

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

“…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.…”

“…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.…”

Bacteria in a hospital nursery: laboratory and clinical studies

“…There was a progressive increase in the isolation rate of staphylococci from the three sites sampled (Fig. 1 Gillespie et al (1958) and Hurst (1960a been previously recorded (Ludlam, 1953;Edmunds et al 1955;Hutchison & Bowman, 1957;Monro & Markham, 1958;Poole, 1960), where the findings ranged from 21 to 58%. This low nasal carriage may be due to exposure to the new penicillins as postulated in the case of infants.…”