生後2週間の新生児の細菌獲得の変化から見た保育器交換の検討 <ワークショップ1>

保育器交換は頻繁に行われるが, その基準や方法についてのエビデンスは確立していない. 我々は, 生後2週間の7名の新生児と児の使用した7台の保育器の細菌培養結果から, 保育器交換の時期について検討した.

方法は, データは当院が実施している入院時からの児の監視培養結果と, 同時期に採取した保育器の細菌培養結果を用い, 事例ごとの検出細菌の変化を検討した.

結果: 出生直後の患児の細菌培養検査は全例で陰性(No Growth)だった. 生後1週間以内の患児と保育器の培養結果はほとんど陰性だった. 生後1週間での保育器交換の必要性は低いことが示された. また患児からと保育器からの検出菌の種類は類似していた.

考察: 無菌状態から細菌を獲得する過程は次のように考察した. 患児が細菌を獲得し, それが保育器に付着する, または保育器に付着した菌が患児に移行している. 保育器交換の主な目的は2つある. ひとつは感染予防, もうひとつは清掃である. 細菌学的には保育器は患児の生活環境の一部であり, 保育器交換を行ってもまた同様の細菌が検出される可能性が高いと考えた. 通常の清拭のみで拭き取りきれない器内の汚染がある場合, 保育器交換が必要である. 患児の生活環境としての清潔の維持, 患児への侵襲, マンパワー, コスト面などを考慮し本当に必要な保育器交換の時期をどこで判断するかが今後の検討課題である.

Objects: Infant incubator exchange (IIE) is performed frequently, but the criteria and evidence about the methods have not been established. We review a timing of infant incubator exchange from a viewpoint of early postnatal bacteria acquisition.

Methods: We reviewed bacteriological examination results of seven newborn patients and incubators in which they have accomodated. A change of acquired bacteria in each case was examined based on bacterial culture results of a newborn since admission and on simultaneous culture results of an infant incubator.

Results: The bacteriological examination of a newborn patient just after birth was negative (no growth) in all cases. Newborn patient of postnatal less than one week and most of an infant incubator were negative in bacterial culture. It was shown that need of IIE in postnatal one week was low. In addition, the kind of cultured bacteria from an infant incubator was similar to it from a patient.

Discussions: The process to acquire bacterial flora from aseptic condition was supposed as follows: patient acquires bacteria, and it sticks to an infant incubator, or the bacteria which stuck to an infant incubator move to a patient. There are two main purposes of IIE, one is to prevent infectious diseases, the other is cleaning. An infant incubator was bacteriologically a part of living environment of a patient, and we thought it was very likely that a similar kind of bacteria can be detected even if an IIE was carried out frequently. When you find contamination in the incubator which cannot being wiped off only in a usual method, IIE is required. Keeping sanitary as living environment of a patient, aggression to a patient, manpower, a cost side must be considered, but it remains controversial how and when to decide a timing of really necessary IIE.