Bacteremia Derived from Clinical Materials on Blood Culture and Catheter Tip after Intravenous Infusion Therapy in a University Hospital

中心静脈内にカテーテル(以下CVCとする)を挿入して行う輸液管理は重症患者への医療には欠くことの出来ないものとなっている一方, カテーテル留置に伴う血流感染の危険性は高い。大学病院におけるCVC由来血流感染症の実態を明らかにするため, 1996年1月から1998年12月までの3年間に広島大学医学部附属病院での各診療科別にみた微生物検査室へのCVCおよび血液の培養依頼状況およびその結果を明らかにした。本調査ではCVCおよび血液の培養の原因菌が一致し, それらの症例について, 薬剤感受性やカルテの内容からCVC挿入が血流感染の直接的な原因になっていたか否かを検討することによりCVC由来菌血症と定義した。血液およびCVCの検査依頼総数は2,233件, 菌検出検体は283件, 検出率は12.7%であった。3年間に検出された菌種の過半数は, 血液およびCVC共にグラム陽性球菌であった。診療科により検出される菌の種類, またその数の違いが見られており, 外科系においてはグラム陽性菌の検出数が多く, 内科系ではグラム陰性菌の検出数が多い傾向が見られたが, 統計的な有意差は認められなかった。血液とCVCから同種の菌検出が認められた症例は13件であり, 1996年に6件, 1997年に5件, 1998年に2件であった。これらの症例を検討した結果, 明らかにCVC由来感染と考えられたものは各年毎2例であり, 原因菌以外の操作中の汚染として見過ごされがちなCoagulase negative-staphylococciが多く見られた。これらのことから, CVC由来血流感染を防止し, 患者の生命予後を改善していくため, CVCを用いた輸液管理に関する正しい理解と正確な技術に基づいたルート管理の必要性が考えられた。To clarify the contamination pattern of samples from central venous catheter tip and blood, all submitted materials by each clinical department from Jan. 1996 to Dec. 1998 were summarized the contaminated cases were determined whether to be catheter-related bacteremia or not. Positive samples were counted as well as those in which bacteria were matched between the catheter tip and the blood. We further checked the later cases from the viewpoint of antibiotic sensitivity and other information in the clinical chart to decide whether the patient had catheter-related bacteremia or not. The total sample materials were 2,233,including 283 (12.7%) bacteria-positive samples. More than halves of the bacteria specimens were gram positive cocci. Detected bacteria differed according to the clinical department. More of the bacteria were gram positive cocci than gram-negative bacilli, the former dominant in the surgical departments than the latter in the non-surgical departments. But these difference were not significant statistically. In thirteen cases, the same bacteria were detected in both the central venous catheter tip and the blood, including six cases in 1996,5 cases in 1997,and 2 cases in 1998,and definitive catheter-related bacteremia was found in 2 cases each year. The other 11 cases were coagulase negative-staphylococci and thought to be contaminated during the sampling maneuver. The medical staff always should keep in mind to improve the patient outcomes by reducing catether-related infections. We must thus have appropriate knowledge and technical skills for catheter administration

Antimicrobial^a susceptibility profiles of recipient strain <i>E. coli</i> and <i>P. aeruginosa</i>.

a<p>PIPC, piperacillin; CAZ, ceftazidime; IPM, imipenem; MEM, meropenem; LVX, levofloxacin; CIP, ciprofloxacin; AMK, amikacin; ABK, arbekacin; DBK, dibekacin; GAN, gentamicin; ISP, isepamicin; KAN, kanamycin; SISO, sisomicin; TOB, tobramycin.</p>b<p>Structure of plasmid KK1 is shown <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0070557#pone-0070557-g002" target="_blank">Fig. 2a</a>.</p

PCR primers used in this study.

<p>PCR primers used in this study.</p

Thin-layer chromatogram of AGs incubated with AAC(6′)-Iag in the presence (+) or absence (−) of acetyl coenzyme A.

<p>KAN, kanamycin; AMK, amikacin; GEN, gentamicin; TOB, tobramycin; DBK, dibekacin; ABK, arbekacin; SISO, sisomicin; ISP, isepamicin.</p

Structure of AGs.

<p>Upper figure denotes basic chemical structure of three rings (A, B and C). R1–8 represents substituents listed in table below.</p

Alignment of 59-base elements (a) and nucleotide sequences of the 367-bp fragment (position 869 to 1,235) (b) of <i>In</i>124.

<p>(a) Seven-base-pair putative core site in the left-hand (LH) and right-hand (RH) consensus sequences are designated 1L, 2L, 2R, 1R, respectively. The sequences of the seven-base-pair putative core site are boxed and the asterisk indicates the extra base in 2L. (b) The −10 and −35 sequences of the putative integrase promoter are underlined with dotted lines and are also located on the complementary strand (P promoter). Analysis of the adjacent region preceding <i>aac(6′)-Iag</i>, <i>bla</i>_IMP-1, <i>Δbla</i>_IMP-1 and <i>Δaac(6′)-Iag</i> found two potential −35 and −10 promoters: P1 promoter (<u>TGGACA</u>…N17…<u>TAAGCT</u>) and P2 promoter (<u>TTGTTA</u>…N14…<u>TACAGT</u>) are present between 899 to 927 and 1,018 to 1,043, respectively. Finally, the putative promoter of <i>aac(6′)-Iag</i> is thought of as the P1. The proposed ribosome-binding site of <i>aac(6′)-Iag</i> is double underlined and is located 3-bp upstream of the start codon of <i>aac(6′)-Iag</i>. The 7-bp core site is wavy lined.</p

Fragment ions of protonated molecules in ESI-MS/MS analysis of aminoglycosides.

<p>P^*: Product ions produced by the ESI were selected to follow ESI-MS/MS analysis as precursor ions.</p><p>n.d.: not detected due to low signal.</p><p>-: not determined due to out of measurement ranges.</p

Kinetic parameters for aminoglycosides.

<p>Each value is mean ± SD of three experiments.</p