Detection of Simkania negevensis by culture, PCR, and serology in respiratory tract infection in Cornwall, UK.

Respiratory tract infections are often treated empirically without investigation to detect the aetiological agent, which may be a virus or a bacterium, including atypical pathogens such as Chlamydophila pneumoniae or Mycoplasma pneumoniae. Recently, several types Chlamydia-like intracellular bacteria have been detected in environmental samples and clinical specimens. Little is known of their geographical distribution and potential pathogenicity. We describe the detection, by PCR and isolation in cell culture, of Simkania negevensis in nasopharyngeal aspirates of paediatric patients with bronchiolitis in Cornwall, UK. We also present serological evidence of exposure to the organism in 62% of adult patients and 46% of a sample of pregnant women. Empirical treatment of serious respiratory tract infection should consider the possible contribution of these organisms.

Serological evidence of acute infection with the Chlamydia-like microorganism Simkania negevensis (Z) in acute exacerbation of chronic obstructive pulmonary disease.

The aims of this study were twofold: (i) to test for possible associations between serological evidence of acute Simkania negevensis (Sn) infection and acute exacerbation of chronic obstructive pulmonary disease and (ii) to examine the prevalence of past infections with Sn in patients with chronic obstructive pulmonary disease. In 120 patients (63%) there was serological evidence of past infection with Sn, which was not significantly different from the rate in a control population. In five hospitalizations serological evidence existed of acute infection with Sn around the time of the exacerbation of chronic obstructive pulmonary disease. In four of these cases, there was serological evidence of acute infection with at least one other respiratory pathogen. It is concluded that Sn can be associated serologically with exacerbation of chronic obstructive pulmonary disease, in most cases together with other respiratory pathogens. The implications of these findings should be investigated further.

Infection of Acanthamoeba polyphaga with Simkania negevensis and S. negevensis survival within amoebal cysts.

Simkania negevensis, a novel microorganism belonging to the family Simkaniaceae in the order Chlamydiales, has an intracellular developmental cycle during which two morphological entities, elementary bodies (EB) and reticulate bodies (RB), are seen by electron microscopy. Rates of seropositivity to the organism are high in certain population groups, and S. negevensis has been associated with respiratory illness in humans. This study reports for the first time the ability of S. negevensis to survive and grow inside Acanthamoeba polyphaga in addition to its known ability to grow in cell cultures of human or simian origin. Infectivity of S. negevensis and growth in amoebae were monitored by immunoperoxidase assays. Long-term persistence and exponential growth of S. negevensis in amoebal trophozoites were demonstrated by infectivity assays and by electron microscopy. EB and dividing RB of S. negevensis were observed within inclusion bodies inside A. polyphaga. When S. negevensis-infected A. polyphaga amoebae were exposed to adverse conditions resulting in encystation of the amoebae, several possible outcomes were observed: cysts containing both normal amoebic cytoplasm and S. negevensis; cysts in which S. negevensis cells were relegated to the space between cyst walls; and cysts containing S. negevensis, but apparently lacking amoebal cytoplasm. S. negevensis within dried amoebal cysts was capable of long-term survival. The possibility that amoebae may have a role in natural transmission of S. negevensis needs to be investigated.

Immunization levels and risk factors for low immunization coverage among private practices.

OBJECTIVES: Previous studies have indicated that provider characteristics are an important determinant of immunization coverage. The objectives of this study were to: 1) assess immunization coverage levels among 2-year-old children receiving care in private practices in 3 California counties; and 2) evaluate practice and patient risk factors for low immunization coverage. STUDY DESIGN: Cross-sectional chart review of immunization histories and provider survey of immunization policies. SETTING: Forty-five randomly selected, private medical practices in 3 counties in California. PATIENTS: Children 12 to 35 months old, followed by the participating practices. METHODS: Providers underwent a detailed assessment of their immunization coverage and completed a questionnaire describing their immunization policies and procedures. Immunization data were abstracted from randomly selected medical charts of children 12 to 35 months old. Only patients who met the criteria for active status (>/=2 visits and >/=1 visit during the preceding 18 months) were included in analyses. Immunization coverage levels were calculated and logistic regression was used to estimate the risk of underimmunization associated with different practice and child characteristics. RESULTS: Of the 72 eligible practices that were contacted, 45 participated in the study, yielding a participation rate of 62%. The median immunization coverage of participating offices was 54% (range: 0%-91%). Multivariate analysis revealed 5 independent risk factors for underimmunization. The strongest predictors were having fewer than 50% active children in the practice and children having fewer than 8 visits to the provider. Other significant predictors were the percentage of patients in the practice on Medicaid, administering diphtheria-tetanus-pertussis 4 at a separate visit from the Haemophilus influenzae type b booster, and practice location. CONCLUSIONS: These data provide new insights into immunization practices in an important clinical setting that has been poorly characterized previously. Immunization coverage levels were found to be low and significant risk factors for underimmunization were identified. Recommendations are made for immunization policy changes and targeting of immunization improvement interventions at practices that may be at risk for low immunization coverage. immunization, vaccination, immunization programs, primary prevention, private practice, child, preschool, pediatrics, family practice.

An unspliced group I intron in 23S rRNA links Chlamydiales, chloroplasts, and mitochondria.

Chlamydia was the only genus in the order Chlamydiales until the recent characterization of Simkania negevensis Z(T) and Parachlamydia acanthamoebae strains. The present study of Chlamydiales 23S ribosomal DNA (rDNA) focuses on a naturally occurring group I intron in the I-CpaI target site of 23S rDNA from S. negevensis. The intron, SnLSU. 1, belonged to the IB4 structural subgroup and was most closely related to large ribosomal subunit introns that express single-motif, LAGLIDADG endonucleases in chloroplasts of algae and in mitochondria of amoebae. RT-PCR and electrophoresis of in vivo rRNA indicated that the intron was not spliced out of the 23S rRNA. The unspliced 658-nt intron is the first group I intron to be found in bacterial rDNA or rRNA, and it may delay the S. negevensis developmental replication cycle by affecting ribosomal function.

Simkania negevensis strain ZT: growth, antigenic and genome characteristics.

Simkania negevensis is the type species of Simkaniaceae, a recently proposed family in the order Chlamydiales. In the current study, growth, antigenic and genomic characteristics of this intracellular bacterium were investigated and compared to those of members of the family Chlamydiaceae. Growth of the organism, as assessed by infectivity assays, reached a plateau in 2-3 d although by light microscopy the cytopathic effect on the host cells increased for 12 or more days after infection. S. negevensis growth was unaffected by sulfadiazine. Cells infected by S. negevensis strain ZT were not recognized by either of two monoclonal antibodies specific for Chlamydiaceae LPS and several specific Chlamydiaceae ompA primers were unable to PCR amplify a S. negevensis gene. The S. negevensis genome contained one copy of the ribosomal operon. The genome size of S. negevensis strain ZT was determined by PFGE to be 1.7 Mbp, and the G + C content was 42.5 mol%. These data, taken together with other published data, are consistent with the proposal that S. negevensis belongs to a distinct family in the order Chlamydiales.

Seroprevalence of IgG antibodies to the chlamydia-like microorganism 'Simkania Z' by ELISA.

The newly described microorganism 'Simkania Z', related to the Chlamydiae, has been shown to be associated with bronchiolitis in infants and community acquired pneumonia in adults. The prevalence of infection in the general population is unknown. A simple ELISA assay for the detection of serum IgG antibodies to 'Simkania Z' was used to determine the prevalence of such antibodies in several population samples in southern Israel (the Negev). The groups tested included 94 medical and nursing students, 100 unselected blood donors, 106 adult members of a Negev kibbutz (communal agricultural settlement), and 45 adult Bedouin, residents of the Negev. IgG antibodies to 'Simkania Z' were found in 55-80% of these presumably healthy individuals, independently of antibodies to Chlamydia trachomatis and Chlamydia pneumoniae. The Bedouin had a seropositivity rate of 80%, while all other groups had rates of between 55 and 64%. These results indicate that 'Simkania Z' infection is probably common in southern Israel.

Modified form factors from multiconfiguration Dirac-Fock wave functions for neutral atoms with Z = 70-100.

Tables of modified X-ray scattering factors for neutral elements with Z = 70-100 have been calculated using multiconfiguration Dirac-Fock wave functions. The physical approximation is a next step beyond the usual form-factor approximation in calculating elastic scattering photon intensities. Differences as large as 3-6% compared to previous calculations of the same kind are obtained; differences from the usual form factors are much larger.

High prevalence of "Simkania Z," a novel Chlamydia-like bacterium, in infants with acute bronchiolitis.

The newly described microorganism "Simkania Z" ("Z"), an obligate intracellular, penicillin-resistant microorganism most closely related to the chlamydiae, has been associated with adult community-acquired pneumonia. The possible involvement of "Z" in bronchiolitis in infants was examined in a prospective study of 239 infants with bronchiolitis and 78 controls. Other potential etiologic agents sought were respiratory syncytial virus (RSV), adenovirus, and cytomegalovirus. Evidence for the presence of "Z" in nasopharyngeal wash specimens (polymerase chain reaction and/or culture) was found in 25% of infants with bronchiolitis, while controls were all negative (P < .001). A serum IgA response to "Z" infection was detected by immunoperoxidase assay in 15% of infants with bronchiolitis versus 1.3% of controls (P < .001). Clinical findings were not different for infants with bronchiolitis associated with RSV alone, "Z" alone, or RSV and "Z" together. The high prevalence of "Z" in infants with bronchiolitis, often accompanied by an immune response, suggests a possible etiologic role of this agent in the disease.

Pneumonia with serological evidence of acute infection with the Chlamydia-like microorganism "Z".

"Z" is a recently discovered microorganism that may belong to a new genus in the family Chlamydiaceae. Using an ELISA test we developed, we measured levels of serum antibody against "Z" for 308 paired sera obtained from adult patients hospitalized with community-acquired pneumonia (CAP). In 114 patients (37%), serological evidence of past infection with "Z" was found. In eight patients (2.6%) there was serological evidence of acute infection with this pathogen. In four of these eight patients, no other pathogen for CAP was identified despite an intensive serological investigation encompassing 13 etiological agents. The four patients were about 30 yr old, and three of them had no history of chronic illness. Their illness was characterized by high fever, a nonproductive cough, gastrointestinal symptoms, a shift to the left in the white blood cell count, and a prompt, dramatic response to erythromycin therapy. We conclude that the microorganism "Z", or a close variant, is infectious for humans, in some cases causing CAP. In these cases the disease is mild and responds quickly to treatment with erythromycin.

Modification of vertical OKN and vertical OKAN asymmetry in humans during parabolic flight.

Characteristics of human vertical optokinetic nystagmus (OKN) and afternystagmus (OKAN) were examined by ISCAN imaging system on the ground and on board NASA's KC-135 aircraft in a parabolic flight study. The aircraft produced alternating periods of micro-(ca. 10(-2) G) and hyper-(ca. 1.8 G) gravitoinertial forces. Each phase lasted approximately 20 to 25 s. As compared to the baseline data on the ground, there was a significant increase of downward OKN/OKAN, whereas the upward OKN/OKAN did not change significantly in either micro- or hyper-G. As a consequence, the asymmetry of vertical OKN/OKAN, normally seen on the ground, was lost. It is postulated that the increase of downward OKN/OKAN in non-1-G conditions was governed by two different mechanisms. In micro-G, the normal inhibition effect in 1 G on the downward eye movement mediated by otolith organ activity to vertical velocity storage was removed. In hyper-G, downward OKN/OKAN was facilitated by augmented otolith-ocular reflex because of increased gravitoinertial force, so as to produce enhanced compensatory downward eye movement.

Designing an emergency medicine physician workstation to support risk management in decision making.

The practice of emergency medicine requires rapid decision making. The speed of decision making in the face of limited information contributes to the high risk of medical malpractice suits. We explore design approaches to an emergency physician electronic medical record product, EMstation, that may reduce the risk of adverse medical events by providing cues and tools while the patient may still be in the emergency department. EMstation is an Emergency Medicine Physician Workstation base on a Microsoft Windows 3.1 user interface. Because adaptation and adaptability to physician needs are critical to user acceptance, design to workflow, multisite end user customization, and integrated database support are used to support risk management documentation in EMstation. This article describes techniques that can be incorporated into electronic medical products which may prevent adverse medical events.

Evidence that the novel microorganism 'Z' may belong to a new genus in the family Chlamydiaceae.

The purpose of this study was to investigate possible phylogenetic relationships of a new microorganism called 'Z'. The organism was previously shown to be similar to chlamydia in its growth cycle and some of its metabolic requirements, but different in others and in its major outer membrane protein. In this study we report the sequencing of 'Z"s 16S ribosomal DNA and comparison of the sequence with that of other microorganisms, including chlamydia and rickettsiae. While chlamydial species have 95.5% sequence identity among themselves, 'Z' had 83% identity with them, and 73% identity with certain rickettsia-like organisms. Based on the sequence analyses and taking into account physiologic considerations, we believe that 'Z' may belong to a novel genus in the family Chlamydiaceae.

Description and partial characterization of a new Chlamydia-like microorganism.

A new obligate intracellular bacterium which we called 'Z' was isolated as a cell culture contaminant of unknown origin. The organism grew in a variety of cultured cells with a 5-7-day developmental cycle, within cytoplasmic phagosomes, similarly to Chlamydia and some Rickettsia spp. Two alternating developmental forms (elementary bodies and reticulate bodies) were observed by electron microscopy. SDS-PAGE electrophoresis, immunoblotting with chlamydia-specific antibodies, and polymerase chain reaction using chlamydial genus specific primers provided evidence that our bacterium differs significantly from chlamydiae. Further characterization of 'Z' including determination of 16S ribosomal RNA sequences will allow its taxonomic position to be established.

Reversibility of heat shock in Chlamydia trachomatis.

The heat shock effect on chlamydia development was studied. We report here that the reversibility of the heat shock response did not depend on the stage of chlamydial morphogenesis at which transfer to high temperature occurred, and the infectivity of the particles produced was not affected significantly, so long as the heat shock exposure was not prolonged. Exposure to heat shock for more than 9 h resulted in stagnation of the growth cycle, appearance of aberrant reticulate body particles and loss of infectivity. SDS-PAGE analysis of proteins synthesized under prolonged heat shock showed increased relative abundance of heat shock proteins in common with other procaryotic organisms.