ABSTRACT
Objective To investigate the antibiotic resistance profile and ftsⅠ genotypes of Haemophilus influenzae isolates from respiratory tract in children.Methods A total of 141 consecutive nonduplicate clinical strains of H.influenzae were collected from January to March 2016.Antimicrobial susceptibility was determined using Kirby-Bauer method.Beta-lactamase production was detected by nitrocefin disk test.PCR technique was employed for ftsⅠ genotyping.Antimicrobial resistance was compared between differentfisⅠ genotypes.Results The prevalence of β-lactamases was 40.4％ (57/141) in H.influenzae isolates.More than half (53.2％,75/141) of the strains were resistant to ampicillin.Mutation offtsI gene was positive in 72.3％ (102/141) of the isolates.The dominant genotype of genomic beta-lactamase-negative ampicillin-resistant (gBLNAR) strains was type Ⅲ (72/102,70.6％).The gBLNAR strains showed higher resistance rate to ampicillin and cefuroxime than the genomic beta-lactamase-negative ampicillin susceptible (gBLNAS) strains (P＜0.05).Conclusions High prevalence offisⅠgene mutation is found in the strains ofH.influenzae isolated from respiratory tract in children.The dominant genotype of gBLNAR strains was type Ⅲ.Mutation offtsⅠ gene in H.influenzae is associated with higher resistance rate to ampicillin and cefuroxime.
ABSTRACT
Objective To investigate the role of nitric oxide(NO)in the spinal cord sensitization in a rat model of neuropathic pain.Methods Thirty-two male adult Wistar rats weighing 200-300 g were randomly divided into 4 groups with 8 animals in each group:group Ⅰ sham operation;group Ⅱ L-NAME pretreatment + sham operation;group Ⅲ CCI and group Ⅳ L-NAME pretreatment + CCI.Neuropathic pain was induced by chronic constrictive injury(CCI).The animals were anesthetized with intraperitoneal pentobarbital 40 mg/kg.The right sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1 mm intervals with 3-0 silk thread.In group Ⅰ and Ⅱ the sciatic nerve was exposed but not ligated.In group Ⅲ and Ⅳ L-NAME 250 μg in normal saline 10 μl was injected into subarachnoid space over 30 seconds at 15 min before sham operation or CCI.The paw-withdrawal threshold to nociceptive thermal stimuli(PWTT)was measured before operation(baseline)and on the 3rd day after operation.Four rats in each group were killed on the 4th and 7th day after operation,and lumbar segment of the spinal cord(L4-5)was removed for determination of expression of pCREB in the dorsal horn of spinal cord by immuno-histochemical technique.Results The paw-withdrawal threshold to nociceptive thermal stimuli(PWTT)was significantly decreased on the 3rd day after operation as compared with the baseline before operation in all 4 groups.The PWTT on the 3rd day after operation was significantly higher in group Ⅰ,Ⅱ and Ⅳ than in CCI group(group Ⅲ),but there was no significant difference in the PWTT after operation among the 3 groups(Ⅰ,Ⅱ,Ⅳ).The expression of pCREB in the dorsal horn neurons of spinal cord was significantly upregulated in CCI group (Ⅲ) as compared with the other 3 groups.Conclusion Spinal cord NO induces hyperalgesia in neuropathic pain through release of pCREB in spinal cord dorsal horn.