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Plaque reduction technique for demonstrating neutralizing antibodies for Chlamydia.

Some members of the genus Chlamydia (Bedsonia or psittacosis-lymphogranuloma venereum-trachoma-inclusion conjunctivitis group of microorganisms) produce plaques in monolayers of mouse fibroblast (L-929) cells. Hyperimmune chicken antisera may be capable of specifically reducing plaque counts. When the test was applied to chlamydiae isolated from avian species, the results indicated that different isolates with a common source had similar antigenic reactivity. The plaque reduction test is a potentially useful method for serotyping chlamydiae. The difficult aspect of the method appears to be a readily reproducible means of producing neutralizing antiserum.

Journal Article↗

Immediate cytotoxicity of Chlamydia trachomatis for mouse peritoneal macrophages.

The toxicity of Chlamydia trachomatis was studied with mouse peritoneal macrophage culture. Inoculation of 30 inclusion-forming units of trachoma B/TW-5/OT organisms and 250 inclusion-forming units of lymphogranuloma venereum L2/434/Bu organisms per cell caused immediated toxicity, with the killing of 40 to 90% of the macrophages within 6 h after inoculation. Inhibition of phagocytosis by adsorption at 0 degrees C or by NaF pretreatment of macrophages prevented the toxicity, indicating that chlamydiae must be phagocytized to induce toxicity. Infectivity and toxicity could be dissociated, since ultraviolet-inactivated chlamydiae were still toxic. However, the toxicity was destroyed by heating the organisms at 56 degrees C for 10 min. Tetracycline, and antichlamydial drug, did not prevent toxicity, indicating that multiplication of the organisms was not required to induce toxicity. Toxicity was not prevented by treatment of macrophages with hydrocortisone. The toxicity of trachoma TW-5 was reduced by the rabbit immune serum of trachoma TW-5 but not by the rabbit immune serum of psittacosis meningopneumonitis.

Animals↗

Comparison of Chlamydia psittaci isolates by restriction endonuclease and DNA probe analyses.

DNAs from eight Chlamydia psittaci isolates (koala conjunctivitis, avian psittacosis, avian ornithosis, ovine abortion, ovine polyarthritis, sporadic bovine encephalomyelitis, and feline conjunctivitis) and one Chlamydia trachomatis isolate (lymphogranuloma venereum) were compared by restriction endonuclease and DNA probe analyses. Digestion with HindIII yielded a series of discrete fragments which allowed the differentiation of most isolates. A gene probe, pFEN207, which encodes the chlamydia-specific component of the lipopolysaccharide group antigen was used in Southern hybridizations. The probe was chlamydia specific and hybridized to a single BamHI fragment and multiple HindIII fragments in each isolate. The variation in size of the hybridizing fragments allowed easy differentiation of the isolates and may eventually lead to a meaningful subgrouping of the diverse group of disease agents presently included in the species C. psittaci.

Animals↗

Structures of and allelic diversity and relationships among the major outer membrane protein (ompA) genes of the four chlamydial species.

DNA sequences coding for 81% of the ompA gene from 24 chlamydial strains, representing all chlamydial species, were determined from DNA amplified by polymerase chain reactions. Chlamydial strains of serovars and strains with similar chromosomal restriction fragment length polymorphism had identical ompA DNA sequences. The ompA sequences were segregated into 23 different ompA alleles and aligned with each other, and phylogenetic relationships among them were inferred by neighbor-joining and maximum parsimony analyses. The neighbor-joining method produced a single phylogram which was rooted at the branch between two major clusters. One cluster included all Chlamydia trachomatis ompA alleles (trachoma group). The second cluster was composed of three major groups of ompA alleles: psittacosis group (alleles MN, 6BC, A22/M, B577, LW508, FEPN, and GPIC), pneumonia group (Chlamydia pneumoniae AR388 with the allele KOALA), and polyarthritis group (ruminant and porcine chlamydial alleles LW613, 66P130, L71, and 1710S with propensity for polyarthritis). These groups were distinguished through specific DNA sequence signatures. Maximum parsimony analysis yielded two equally most parsimonious phylograms with topologies similar to the ompA tree of neighbor joining. Two phylograms constructed from chlamydial genomic DNA distances had topologies identical to that of the ompA phylogram with respect to branching of the chlamydial species. Human serovars of C. trachomatis with essentially identical genomes represented a single taxonomic unit, while they were divergent in the ompA tree. Consistent with the ompA phylogeny, the porcine isolate S45, previously considered to be Chlamydia psittaci, was identified as C. trachomatis through biochemical characteristics. These data demonstrate that chlamydial ompA allelic relationships, except for human serovars of C. trachomatis, are cognate with chromosomal phylogenies.

Alleles↗

Properties of quinoxaline oxide-resistant Rickettsia typhi.

Weiss, Emilio (Naval Medical Research Institute, Bethesda, Md.) and Harry R. Dressler. Properties of quinoxaline oxide-resistant Rickettsia typhi. J. Bacteriol. 83:415-417. 1962.-An effort was made to apply to the Wilmington strain of Rickettsia typhi the observation that in certain strains of rickettsiae and viruses of the psittacosis group quinoxaline oxide resistance is easily obtained and is often accompanied by other changes. Resistance to quinoxaline oxide was obtained in R. typhi after 14 serial egg passages by a procedure somewhat more elaborate than the one used previously for R. prowazekii. Three limit-dilution isolates manifested an appreciable level of drug resistance (were unaffected by 0.5 mg/egg), but changes for unselected characteristics, such as "toxicity" for the mouse or growth or virulence for the chick embryo, were small and different in each case, and did not clearly resemble those obtained with the other microorganisms.

Animals↗

DIAMINOPIMELIC ACID DECARBOXYLASE OF THE AGENT OF MENINGOPNEUMONITIS.

Moulder, James W. (University of Chicago, Chicago, Ill.), Dorothy L. Novosel, and Ilse C. Tribby. Diaminopimelic acid decarboxylase of the agent of meningopneumonitis. J. Bacteriol. 85:701-706. 1963.-Evidence is presented for the presence in meningopneumonitis particles and extracts of an enzyme decarboxylating alpha, epsilon-diaminopimelic acid to lysine and for the absence of a corresponding enzyme in the uninfected host. Properties of the enzyme are described and compared with those of bacterial diaminopimelic acid decarboxylases. The significance of these observations with respect to the mode of lysine biosynthesis in the psittacosis group and to its phylogenetic origin is pointed out.

Carboxy-Lyases↗

CHANGES IN MOUSE PNEUMONITIS AGENT ASSOCIATED WITH DEVELOPMENT OF RESISTANCE TO CHLORTETRACYCLINE.

Moulder, James W. (University of Chicago, Chicago, Ill.), Dorothy L. Novosel, and Ilse I. E. Tribby. Changes in mouse pneumonitis agent associated with development of resistance to chlortetracycline. J. Bacteriol. 89:17-22. 1965.-A chlortetracycline-resistant mutant of mouse pneumonitis agent, a member of the psittacosis group of microorganisms, differed in several ways from the susceptible stock from which it had been derived by serial chick-embryo passage in the presence of the antibiotic. It was almost completely resistant to chlortetracycline, had a longer growth cycle, produced many more very large particles, was not neutralized by parent antiserum and vice versa, was 10 times as resistant to d-cycloserine, and was highly lethal to mice when inoculated intracerebrally. These changes probably do not occur independently of one another but are the reflection of some genetically controlled change in the surface structure of the mouse pneumonitis particle which enables the resistant mutant to multiply in the presence of chlortetracycline.

Alanine↗

Electron microscopy of tick-borne fever agent in bovine and ovine phagocytizing leukocytes.

Tuomi, Jaakko (University of Helsinki, Helsinki, Finland), and C.-H. von Bonsdorff. Electron microscopy of tick-borne fever agent in bovine and ovine phagocytizing leukocytes. J. Bacteriol. 92:1478-1492. 1966.-Two strains of tick-borne fever agent, one more virulent to cattle and the other more virulent to sheep, were studied in thin sections of leukocyte concentrates of an affected calf and sheep, respectively. The calf was partially immune from previous infections. To obtain leukocyte concentrate, erythrocytes were lysed by ammonium chloride solution. Glutaraldehyde fixation and osmium tetroxide postfixation were used. Agent particles were detected in neutrophil and eosinophil granulocytes (occasionally also in monocytes) inside cytoplasmic vacuoles. The preparation from the sheep revealed that the tick-borne fever agent has a life cycle; it appeared as large particles, intermediate forms, and small particles. In the preparation from the calf, only large particles were observed, probably as a result of partial immunity. Large particles had a cell wall, plasma membrane, cytoplasm with ribosome-like granules, and nucleoid. They were often elongated, bearing closer resemblance to rickettsiae than to psittacosis-lymphogranuloma-trachoma (PLT) agents. The arrangement of large particles in vacuoles was variable and provided an explanation for the different forms of light microscopic tick-borne fever bodies. The intermediate forms and small particles resembled those of PLT organisms. Release of particles occurred by rupture of inclusions. In the calf also extrusion of whole inclusions was observed. This phenomenon was thought to reflect increased resistance of the cells. The large particle was considered to be the usual infective form of the agent. A middle-ground position of the agent between the genus Rickettsia and the PLT group is suggested.

Animals↗

Initial step in catabolism of glucose by the meningopneumonitis agent.

The relative rates of catabolism of glucose and glucose-6-phosphate by intact-cell suspensions of the meningopneumonitis agent, a member of the psittacosis group (Chlamydia), and the properties of the hexokinase and glucose-6-phosphate dehydrogenase of these suspensions were investigated. It is proposed that the hexokinase is a host enzyme bound to the surface of the meningopneumonitis cell and that glucose-6-phosphate is the first substrate in the conversion of hexose to pentose to be attacked by enzymes synthesized by the meningopneumonitis agent.

Animals↗

Validation of Legionella pneumophila indirect immunofluorescence assay with epidemic sera.

Sera from six outbreaks of legionellosis and four outbreaks of pneumonia of other etiologies were tested with the indirect immunofluorescence assay (IFA) as currently performed. The current IFA is at least as sensitive as the original test in detecting cases of Legionnaires disease (78 to 91%). By using Center for Disease Control criteria for a positive (fourfold increase in titer during convalescence to greater than or equal to 128) or presumptive (single titer greater than or equal to 256) serological test, the specificity exceeded 99%. No cross-reactions against Legionella pneumophila antigens were observed among sera from epidemic cases of Q fever, tularemia, and psittacosis; the only positive L. pneumophila IFA titer among the epidemic Mycoplasma pneumonia sera was reduced to a negative titer with an immunosorbent extracted from Escherichia coli strain O13:K92:H4. The slight increase in specificity (to 100%), however, was offset by a slight decrease in sensitivity. The sensitivity of the IFA was maximal when a conjugate that detected immunoglobulins G, M, and A was used. IFA titers were not significantly altered by replacing the monovalent serogroup 1 antigen with a polyvalent antigen (serogroups 1 through 4) nor by the presence of rheumatoid factor or heat-labile serum factors.

Antibodies, Bacterial↗

Treatment of congestive cardiomyopathy.

Although the majority of patients with cardiomyopathy are in the category of primary or idiopathic cardiomyopathy, for which therapy is symptomatic and non-specific, there are a number of secondary forms of cardiomyopathy for which specific therapy is available, thus giving impetus to prompt and accurate diagnosis. Among inflammatory lesions, brucellosis, psittacosis and toxoplasmosis are examples. Treatable metabolic causes include thyrotoxicosis and thiamine deficiency, the latter as well as calorie-protein malnutrition are also preventable. There is presumptive evidence that the cardiomyopathy of haemochromatosis is benefited by repeated phlebotomies. Symptomatic relief of obstructive cardiomyopathy is achieved by beta-adrenergic blockade, although resection of obstructing myocardium still has a place. The therapeutic approach to the vast majority of cases of congestive cardiomyopathy is non-specific, comprising controlled activity, sodium restriction, digitalis and diuretics. Vasodilators and, occasionally, beta-adrenergic blockade may be beneficial. Pacemakers may be life-saving, whereas the place of anti-arrhythmics remains uncertain. Transplantation warrants further application. Valve replacement has little to offer. Primary prevention, comprising balanced nutrition, vaccines and genetic counselling, merits wider application. In individuals at risk or already afflicted, programmes of secondary prevention should include good nutrition, abstinence from alcohol and protection from drugs and toxins.

Cardiomyopathies↗

Causes of pneumonia presenting to a district general hospital.

The incidence of bacterial, viral, mycoplasma, and rickettsial infections has been assessed prospectively in 210 adult patients with pneumonia who presented to a district hospital over a six-year period. One hundred and thirteen infective agents were detected in 103 patients. The agent most frequently detected was Mycoplasma pneumoniae which accounted for 30 infections. A bacterial pathogen was found in 43 patients. Streptococcus pneumoniae was the most common of these (24 patients); Staphylococcus aureus (eight), Haemophilus influenzae (four), Klebsiella spp (three), and Legionella pneumophila (three) were all less common. Chlamydial or rickettsial infections (Psittacosis or Q fever) were detected in nine patients. Viral infections were found in 31 patients (22 influenza A, four influenza B, two parainfluenza, and three respiratory syncytial virus). There were 10 patients in whom more than one pathogen was identified. In 107 patients no pathogens could be identified. Seventy-five per cent of these patients had either received antibiotics before entering hospital, or were unable to produce any sputum for culture. The incidence of bacterial pneumonia has probably therefore been underestimated. Nevertheless this survey does emphasise the importance of M pneumoniae as a pathogen in patients with pneumonia presenting to hospital.

Adult↗

The chlamydial pneumonias.

Chlamydia psittaci and Chlamydia pneumoniae are important causes of community-acquired pneumonias. Less commonly, C. trachomatis may cause pneumonia in adult immunocompromised hosts but more commonly is responsible for pneumonia in neonates. C. psittaci is the cause of psittacosis and is the only chlamydial zoonotic atypical pneumonia. C. pneumoniae is being increasingly recognized as the cause of up to 10% of community-acquired pneumonias. C. pneumoniae pneumonia has a clinical presentation like Mycoplasma pneumoniae pneumonia. C. pneumoniae is also responsible for a variety of other respiratory tract infections, e.g., sinusitis, bronchitis, otitis, pharyngitis and laryngitis. C. pneumoniae, like M. pneumoniae, may result in permanent airway disease, e.g., asthma, following infection. All chlamydia are sensitive to doxycycline. Macrolides are highly active against C. trachomatis, and in spite of in vitro susceptibility, are relatively inactive in vivo against C. psittaci and C. pneumoniae. Fluoroquinolones are also active against chlamydia. Doxycycline remains the preferred antibiotic to treat all chlamydial infections in nonpregnant adults.

Journal Article↗

Special challenges of maintaining wild animals in captivity in South America.

The author summarises the occurrence of major diseases in wild animals maintained in captivity in South America. The epidemiology, impact and significance of the diseases are discussed, together with appropriate husbandry practices to control and prevent transmissible diseases. The following animal groups and pathologies are considered in this review: poxvirus dermatitis, gastroenteritis, pneumonia, amoebosis and coccidiosis in reptiles, management practices and diseases (including botulism, bacterial enteritis, psittacosis, aspergillosis and parasitic diseases in birds), enterocolitis, pneumonias and internal parasites in non-human primates, canine distemper, parvoviruses, babesiosis, internal and external parasites in carnivores, tuberculosis and enteritis in tapirs, haemorrhagic disease in cervids.

Animal Husbandry↗

Mycoplasma pneumonia: a study on hospitalized American patients with pneumonia in Vietnam.

A prospective study on consecutively hospitalized pneumonia patients showed that 41.5% of 58 patients had a fourfold rise in the complement-fixation titer for Mycoplasma pneumoniae. Viral isolation techniques and serologic tests for influenza A1, A2 and B, parainfluenza 1 and 3, respiratory syncytial virus and the adeno virus group yielded only a single positive isolate for influenza A2. Serologic tests for melioidosis, leptospirosis, scrub, murine and epidemic typhus and psittacosis were all negative. The clinical manifestations were not distinctive for the positive M. pneumoniae patients when compared with the patients having a negative M. pneumoniae complement-fixation test. The symptoms and signs and laboratory and radiologic findings were similar to those described in other reports on primary atypical pneumonia.

Adult↗

A serologic survey of mule deer and elk in Utah.

Sera from mule deer (Odocoileus hemionus) and elk (Cervus canadensis) in central and northern Utah were tested for the prevalence of antibodies to 11 diseases communicable to man or domestic livestock. Antibodies to Francisella tularensis (at 1:20) were found in 47 of 88 (53.4%) elk and 1 of 89 (1.1%) deer. A screening slide agglutination test for titers to Brucella (at 1:20) showed two reactors in elk but none in deer sera. No positive antibody titers were obtained in tests for anaplasmosis, Colorado tick fever, Rocky Mountain spotted fever, Q-fever, psittacosis, Powassan, western equine encephalitis, St. Louis encephalitis and California encephalitis.

Animals↗

Investigations on some antigenic relationships between different human, mammalian and avian Chlamydia strains.

Serological investigations were performed in order to establish the antigenic relationships between three Chlamydia strains: T44(subgroup A), T13 and Q18 (subgroup B). By using monospecific mouse immune sera a certain degree of antigenical relationships was made evident and the strains could be typed by microagglutination and microimmlnofluorescence reactions. Similar results were obtained by seroneutralization with hyperimmune sera prepared in the rooster. Complement fixation proved to be a group-specific reaction unable to reveal significant differences between the strains studied, not even with monospecific mouse sera. The antigenic relationships established between strains T44 (trachoma) and T13 (psittacosis) suggest the existence features common to subgroup A and B Chlamudia strains. The importance of typing Chlamudia strains with a view to specific prophylaxis is emphasized.

Animals↗

[Chlamydial diseases of domestic animals--zoonotic potential of the agents and diagnostic issues].

The role of chlamydiae as agents of a number of important animal and human diseases is still the subject of intensive research. Recently, a proposal for taxonomic reclassification of this group of obligate intracellular bacteria was published, which was based on a large amount of new data on genetic relatedness. According to this proposal, the family Chlamydiaceae now comprises two genera (Chlamydia and Chlamydophila) with 9 largely host-related species. The previously accepted classification scheme had distinguished 4 species within the genus Chlamydia. The most important animal chlamydiosis with zoonotic character is psittacosis, a systemic disease in psittacine birds of acute, protracted, chronic or subclinical manifestation. The analogous infection in domestic and wild fowl is known as ornithosis. Avian strains of C. psittaci (new classification: Chlamydophila psittaci) can also infect humans, the symptoms being mainly unspecific and influenza-like, but severe pneumonia, endocarditis and encephalitis are also known. The main group of persons facing an elevated risk of infection includes those having frequent contact with domestic and companion birds at work or in their spare time. In Germany, the annual average of notified cases is approximately 100. Cases of transmission to humans were repeatedly reported in connection with enzootic abortion in sheep (causative agent: C. psittaci or Chlamydophila abortus, respectively). Various chlamydial species occur as pathogens and commensals as well in cattle, pigs, horses, and cats. The assessment of the actual epidemiological importance is, however, often difficult because of their almost ubiquitous spread. Likewise, those strains of C. pneumoniae (new classification: Chlamydophila pneumoniae) found in several animal species can not yet be assessed for pathogenic properties. The possibilities for diagnostic detection of chlamydiae have considerably improved following the introduction of molecular methods, particularly the polymerase chain reaction (PCR), which permits direct identification from clinical specimens and differentiation of species.

Animals↗