Details

Autor(en) / Beteiligte

• Cheng, V.C.C
• Li, I.W.S
• Wu, A.K.L
• Tang, B.S.F
• Ng, K.H.L
• To, K.K.W
• Tse, H
• Que, T.L
• Ho, P.L
• Yuen, K.Y

Titel

Effect of antibiotics on the bacterial load of meticillin-resistant Staphylococcus aureus colonisation in anterior nares

Ist Teil von

• The Journal of hospital infection, 2008-09, Vol.70 (1), p.27-34

Ort / Verlag

Kent: Elsevier Ltd

Erscheinungsjahr

2008

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Summary Prevalence of hospital-acquired meticillin-resistant Staphylococcus aureus (MRSA) infection or colonisation has been associated with antimicrobial consumption. The impact of antibiotic treatment on nasal colonisation is unknown. We conducted a three-month prospective study of 116 patients with extranasal MRSA infection or colonisation, whose nasal MRSA bacterial loads were determined during and after various antibiotic courses over a period of three weeks. Environmental swabs were also taken from the near patient environment. Concomitant nasal MRSA carriage was observed in 76.7% of extranasal MRSA-colonised or -infected patients. The median nasal MRSA bacterial load increased significantly from 2.78 (range 0–6.15) to 5.30 (range 2.90–8.41) log10 cfu per swab (cfu/swab) ( P < 0.001) over 21 days during β-lactam therapy. It also increased from 0 (range 0–4.00) to 4.30 (range 0–7.46) log10 cfu/swab ( P = 0.039) over 14 days during fluoroquinolone therapy. Median bacterial loads were significantly higher for β-lactam- and fluoroquinolone-treated patients on day 7 [4.78, range 0–7.30], day 14 [4.30, range 0–7.60] and day 21 [5.30, range 2.90–8.41] than controls not receiving antibiotics ( P < 0.05). These loads then decreased by 2–5 log10 cfu/swab 2 weeks after discontinuation of antibiotics. The environment of patients receiving β-lactam agents (relative risk: 3.55; 95% confidence interval: 1.30–9.62; P = 0.018) or fluoroquinolones (4.32; 1.52–12.31; P = 0.008) demonstrated more MRSA contamination than the environment around control patients (0.79; 0.67–0.93; P = 0.002). Patients on β-lactam or fluoroquinolone therapy have increased incidence of MRSA colonisation and higher nasal bacterial loads, and appear to spread their MRSA into the near patient environment.