儿童呼吸道肺炎支原体感染的实验室诊断

目的同时用目前常用的几种诊断肺炎支原体（MP）感染的实验方法检测MP,相互比较,得出适于常规诊断MP感染的方法或组合。方法搜集我院于2006年10月至2007年5月间以呼吸道感染入院儿童病例75例,采集其咽拭子和双份血清标本,以多种方法检测有无MP感染：培养法、EIA法测抗原、PCR法测MP-DNA,ELISA法测MP特异性IgG、IgA型抗体以及捕获法ELISA测MP特异性IgM型抗体。结果上述75例儿童中,共计有12例感染MP。以此为基础,上述各方法的敏感度分别是：培养法（25％）、EIA法测抗原（8．3％）、PCR法测MP-DNA（75．0％）、ELISA法测MP特异性IgA型抗体（单份血清为0,双份血清为33．3％）、捕获法ELISA测MP特异性IgM型抗体（单份血清为66．7％,双份血清为100％）。特异度分别是：100％、96．8％、93．7％（93．7％）、98．4％（98．4％）。PCR法和捕获法ELISA测MP特异性IgM型抗体结合后敏感度和特异度分别达到100％和95．2％。结论PCR法测MP-DNA和捕获法ELISA测MP特异性IgM型抗体的组合可高效地诊断MP感染,因而可作为临床诊断MP感染的一个常规组合。     

大学生解脲脲原体和人型支原体正常携带状况研究

目的探讨解脲脲原体(Uu)和人型支原体(Mh)在大学生中的正常携带状况.方法采用培养法对314名未婚统招大学生和232名已婚成教大学生进行解脲脲原体和人型支原体的检测.结果未婚大学生和已婚大学生泌尿生殖道支原体检出率分别为12.10%和22.41%,后者明显高于前者(x2=10.31,P＜0.005);已婚男、女大学生泌尿生殖道支原体检出率(分别为17.44%和27.78%)明显高于未婚男、女大学生检出率(分别为8.33%和16.44%,x2=5.84、4.77P＜0.05).未婚男、女大学生之间泌尿生殖道支原体检出率差异有显著性(y2=4.82,P＜0.05),而已婚男、女大学生之间泌尿生殖道支原体检出率差异无显著性(x2=3.34,P＞0.05).已婚和未婚大学生泌尿生殖道支原体检出者中均以同时携带Uu和Mh较为常见.结论在校大学生中也有一部分人正常携带Uu和/或Mh,从他(她)们体内检出Uu和/或Mh一般不代表疾病状态.     

Killing rate curve and combination effects of surfactin C produced from Bacillus subtilis complex BC1212 against pathogenic Mycoplasma hyopneumoniae

This study evaluated the killing rate as well as the antimycoplasmal effect of surfactins isolated from Bacillus subtilis complex BC1212, either alone or in combination with various antibacterials against Mycoplasma hyopneumoniae. Prior to the killing rate and the combination effect studies of surfactins, the minimal inhibitory concentrations (MICs) of various antibacterials and surfactins (consisting of surfactins A, B, C, and D) against M. hyopneumoniae were investigated. The MIC of all surfactins was found to be 64 μg/ml. The MICs of colistin (COL), norfloxacin (NFX), oxytetracycline (OTC), streptomycin (SM) and tiamulin (TIA) were >256, 0.063, 0.025, 4, and 0.015 μg/ml, respectively. In the killing rate curve studies, surfactin C at 2× MIC and 4× MIC concentrations was found to reduce viability by >3 log₁₀ c.c.u./ml within 2–4 h of incubation. Combination of surfactin C with other antibacterials showed additive interaction from the viewpoint of fractional inhibitory concentration (FIC) index of >0.5 but ≤2 as a borderline. Taking all results into consideration, surfactin C may be useful as a preventive or therapeutic adjuvant in the pathogenesis of mycoplasmal infection.     

Age‐specific infectious period shapes dynamics of pneumonia in bighorn sheep

Superspreading, the phenomenon where a small proportion of individuals contribute disproportionately to new infections, has profound effects on disease dynamics. Superspreading can arise through variation in contacts, infectiousness or infectious periods. The latter has received little attention, yet it drives the dynamics of many diseases of critical public health, livestock health and conservation concern. Here, we present rare evidence of variation in infectious periods underlying a superspreading phenomenon in a free‐ranging wildlife system. We detected persistent infections of Mycoplasma ovipneumoniae, the primary causative agent of pneumonia in bighorn sheep (Ovis canadensis), in a small number of older individuals that were homozygous at an immunologically relevant genetic locus. Interactions among age‐structure, genetic composition and infectious periods may drive feedbacks in disease dynamics that determine the magnitude of population response to infection. Accordingly, variation in initial conditions may explain divergent population responses to infection that range from recovery to catastrophic decline and extirpation.     

550例支原体药敏结果分析

目的：了解本地区感染泌尿生殖系的解脲、人型支原体耐药情况。方法：对性病科和妇科门诊近3年来550例支原体感染者用支原体药敏试剂盒进行司巴沙星（SPA）、克拉霉素（CLA）、可乐必妥（CRA）、交沙霉素（JOS）、阿奇霉素（AZI）、罗红霉素（ROX）、强力霉素（DOX）、美满霉素（MIN）、氧氟沙星（ODL）、乙酰螺旋霉素（ASP）、四环素（TET）、红霉素（ERY）12种抗生素的药敏试验。结果：统计近3年耐药率,总计依次是4.2%、8.4%、10.4%、23.2%、23.8%、29.6%、29.6%、33.0%、43.1%、55.3%、61.9%、82.7%。结论：耐药率司巴沙星、克拉霉素、可乐必妥较稳定,基本低于10%,其余均较高且大部分呈逐年增长趋势,且解脲和人型支原体耐药性有较大差异。     

Contrasting effects of Mycoplasma fermentans and M. felis on the viability and chemiluminescence response of human polymorphonuclear leukocytes

Abstract Trypan blue exclusion was used to estimate the viability of human polymorphonuclear leukocytes (PMNL) in the presence of Mycoplasma felis and two strains of M. fermentans (PG18 and incognitus). The competence of PMNL to mount a respiratory burst when challenged with the mycoplasmas was also monitored by luminol-dependent chemiluminescence (CL). Both un-opsonised and non-immune human serum opsonised M. felis cells had little effect on PMNL viability. In contrast, PMNL viability was reduced markedly by un-opsonised cells of M. fermentans strain incognitus and, to a lesser extent, strain PG18, and opsonisation of these mycoplasmas further enhanced killing. Death of PMNL in the presence of M. fermentans was not associated with the autonomous production of active oxygen species during the respiratory burst as M. felis induced a high CL response from PMNL, whereas that induced by M. fermentans strain incognitus was significantly lower. M. fermentans may invade mammalian cells and it is suggested that the mechanism of PMNL death could be related to the ability of M. fermentans to penetrate host cell membranes.     

Characterization of a major Mycoplasma penetrans lipoprotein and of its gene

Abstract A novel mycoplasmal species designated as Mycoplasma penetrans has been isolated recently from patients infected with human immunodeficiency virus. p35, a major antigen extracted from the membrane of this mycoplasma using Triton X-114 has been found to be a lipoprotein. After proteolytic treatment of p35, the sequence of one of the resulting peptides was determined and a corresponding oligonucleotide was deduced. Using this oligonucleotide as a probe the p35 gene was cloned and sequenced. Sequence analysis revealed an amino-terminal signal peptide with a potential acylation site which would result in a 35.3 kDa mature product. In addition, the p35 gene was followed by an open reading frame with a corresponding polypeptide partially homologous to p35, in particular to the N-terminus region.     

Rapid detection of tetM in Mycoplasma hominis and Ureaplasma urealyticum by PCR: tetM confers resistance to tetracycline but not necessarily to doxycycline

Tetracycline resistance in Mycoplasma hominis and Ureaplasma urealyticum has been associated with the tetM determinant and has recently been increasing in incidence. We report here a rapid method for detection of the tetM determinant based on the use of the polymerase chain reaction (PCR) to amplify a 397-bp DNA fragment from the tetM gene and verification of specificity using the restriction enzyme TaqI. Analysis of 42 U. urealyticum and 49 M. hominis isolates indicates that the PCR method may be clinically useful for determination of tetracycline sensitivity, as tetM is presently the only known determinant associated with tetracycline resistance in these two organisms. All of the tetM-positive M. hominis isolates were sensitive to doxycycline, indicating that tetM does not necessarily confer resistance to this antibiotic.     

Active K+ transport in Mycoplasma mycoides var. Capri. Relationships between K+ distribution,electrical potential and ATPase activity

The addition of 5 · 10^?5 M or less of dicyclohexylcarbodiimide to Mycoplasma mycoides var. Capri preferentially influences K⁺ influx rather than efflux and reduces by 30–40% the activity of the membrane-bound Mg²⁺-ATPase. Adding valinomycin to metabolizing cells does not markedly affect K⁺ distribution but induces a rapid and complete loss of intracellular K⁺ in non-metabolizing cells. Uncoupling agents such as dinitrophenol, carbonyl cyanide $\text{p-}\text{trifluoromethoxyphenylhydrazone}$, dissipate the K⁺ concentration gradient only when combined with valinomycin.Variations in the merocyanine fluorescence intensity indicate that a transmembrane electrical potential (Δψ) is generated on cell energization. This Δψ, not affected by valinomycin or uncouplers when used alone, is collapsed by a mixture of both. No change in fluorescence intensity can be detected when glucose is added to dicyclohexylcarbodiimide treated organisms.These experiments suggest that the membrane-bound Mg-ATPase activity controls K⁺ distribution in these organisms through the generation of a transmembrane electrical potential difference.