Distribution and Prevalence of Antimicrobial Susceptibility in Isolates from Cerebrospinal Fluid Specimens in Shanghai,1995-2004 / 中华医院感染学杂志

20 antimicrobial agents were determined by Kirby-Bauer methods by the participating institutions.RESULTS A total of 428 strains were isolated,Gram-positive cocci and Gram-negative bacilli accounted for 49.8% and 50.2%,respectively.The Gram-positive bacteria increased from 44.6% to 51.2% from 1995-1996 through 2003-2004 and Gram negative bacteria decreased from 55.4% to 48.2% in the meantime.The most frequent Gram-positive isolates were coagulase negative staphylococci,Staphylococcus aureus,Enterococcus spp and Streptococcus pneumoniae;the most frequent Gram-negative isolates were Acinetobacter spp,Klebsiella spp,Escherichia coli,Pseudomonas aeruginosa and Enterobacter spp;Neisseria meningitidis,Haemophilus influenzae,Flavobacterium spp and Citrobacter spp were relative less common.No strains resistant to vancomycin were found in staphylococci and enterococci.Gram-negative bacilli were highly susceptible to carbapenem.CONCLUSIONS Gram-positive cocci play an increasing role in central nervous sysytem infections,especilly coagulase negative staphylococci,and Gram-positive cocci have been increasing from 1995-1996 through 2003-2004,resistance to the first line antibiotics is common among all cerebrospinal fluids isolates.

Contractile effects of hemoglobin-free human cerebrospinal fluid on isolated porcine cerebral arteries

To elucidate the mechanism involved in the cerebral vascular spasm following subarachnoid hemorrhage (SAH), the effects of the cerebrospinal fluid (CSF) obtained from the SAH patients on the resting tension and its influence on the contractile responses to various vasoactive agents and to hypoxia were investigated in isolated porcine cerebral arteries. All the CSFs containing hemoglobin (Hb) produced contraction and some Hb-free CSFs also elicited contraction. When the Hb-free CSF was separated by microfilter, the filtrate of < 30,000 MW did not produce contraction, while the fraction above 30,000 MW elicited more marked contractile responses than the unfractionated CSF. The CSF contraction was significantly attenuated in the presence of indomethacin or nimodipine, whereas the contractions induced by KCl, prostaglandin F2alpha (PGF2alpha), or endothelin-1 (ET-1) were not affected by the CSF pretreatment. However, the contractile responses induced by 5-hydroxytryptamine (5-HT) and phenylephrine (PE) were markedly potentiated by the pretreatment. Hypoxia-induced vasoconstriction was significantly potentiated by the pretreatment with either unfractionated CSF or the CSF fraction of above 30,000 MW. These results suggest that unknown vasocontractile substance(s) exists in the Hb-free CSF and that the substance, with its MW above 30,000, is activated by hypoxia and acts synergistically with 5-HT and PE, and that extracellular calcium influx and cyclooxygenase are also involved in the cerebral vasoconstrictory effect of Hb-free CSF.