Is plasmid based differentiation ofCoxiella burnetii in ‘acute’ and ‘chronic’ isolates still valid?

Ten humanCoxiella burnetii isolates from french patients with acute hepatitis or chronic endocarditis were characterized according to their polymorphism in DNA restriction patterns and differentiated by plasmid-specific PCR. The aim of this investigation was to clarify if the present classification of so called acute and chronicCoxiella burnetii isolates — based on plasmid profile of a so far limited number of partly ancient isolates — could be confirmed with lately isolated organisms of this agent. The data obtained in this investigation indicate that this classification based onC. burnetii plasmid content is no longer justified.     

Pathogenesis of rickettsial infections emphasis on Q fever

The underlying mechanisms at the organismic, cellular and molecular levels that account for rickettsial pathogenesis are beginning to be revealed. In the case of Coxiella burnetii infection, relatively recent genetic and biochemical data, as well as drug susceptibility studies, indicate a correlation between isolate type and clinical disease — chronic or short-term acute. The use of cultured cells as model host systems has revealed that, indeed, different isolates from the major classified strains of C. burnetii cause different host cell responses. Use of this and other models (guinea pigs, mice) have revealed other characteristics and properties of the rickettsiae and the infected hosts and host cells that may account, in part, for acute disease and persistent infection culminating in chronic disease. The virulence factors involved apparently include the agent's surface lipopolysaccharide; other unidentified factors have not been excluded. Molecular cloning will play a major role in elucidating the roles of these factors and in identifying other virulence determinants.Presented at the 4th International Symposium on Riskettsial and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Isolation ofCoxiella burnetii and of an unknown rickettsial organism fromIxodes ricinus ticks collected in Austria

Two strains ofCoxiella burnetii and two strains of an unidentified rickettsial organism were isolated for the first time fromIxodes ricinus ticks collected in the Alpine region of Tirol, Austria. TheC. burnetii strains belong to the group of agents causing acute forms of Q fever. The other two strains of isolated rickettsial agent share some antigenic epitopes withC. burnetii andR. prowazekii but they differ from them by their high sensitivity to freezing and refreezing and by poor multiplication in yolk sacs of chick embryos. There is at present no evidence that these organisms cause human illness and no ecological information is available. We suggest they may be some new species of rickettsiae or rickettsia-like organisms.     

Rickettsiae and rickettsioses in Portugal

The only rickettsiae recorded in Portugal till now were Rickettsia conorii and Coxiella burnetii. Boutonneuse fever is one of the most important transmissible diseases in Portugal. Though the annual number of cases is not exactly known, it is estimated to be not far from 20,000 in some years. Q fever is the other rickettsiosis widely disseminated throughout the country. The serological prevalence and the incidence of those rickettsioses in Portugal are presented in this communication. In recent research in southern Portugal, about 4,000 adult ticks of nine species were screened by the haemocyte test for rickettsiae and rickettsia-like organisms (RLO). In addition to R. conorii three microscopically different RLO were observed. Two of them, i.e. ovoid and bacillary-like, were positive in the immunofluorescence test with spotted fever (R. conorii) antiserum. The first occurred mainly in Rhipicephalus sanguineus ticks, the second one also in other tick species. The latter agent was cultivated in half-engorged R. sanguineus females and in Vero cells. The third organism was found in R. sanguineus, where it exhibited a massive infestation in haemocytes resembling that seen in experimentally infected ticks with C. burnetii, but not being this agent. The investigation of the isolates and their identification and characterization are being continued.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Comparison of an improved RAPD fingerprinting with different typing methods for discriminating clinical isolates of Staphylococcus spp.

Different epidemiological markers were used to characterize 2 Staphylococcus epidermidis and 8 Staphylococcus aureus strains isolated from patients with severe infections. We compared random amplified polymorphic DNA (RAPD) fingerprints, biotypes, antibiotic assays, plasmid profiles and chromosomal DNA restriction endonuclease analysis (REA). Data analysis based on numerical taxonomy methods indicates that RAPD and REA give similar results allowing a good discrimination of the two species and of each isolate. The RAPD method is easier and faster than REA, but the reproducibility of RAPD fingerprints obtained in independent experiments can be problematic. We have found simple technical devices to improve the reproducibility of the RAPD procedure which is therefore a very useful tool in epidemiology for identification and characterization of Staphylococcus spp.     

Screening for Q Fever in Patients Undergoing Transcatheter Aortic Valve Implantation,Israel, June 2018–May 2020

Q fever infective endocarditis frequently mimics degenerative valvular disease. We tested for Coxiella burnettii antibodies in 155 patients in Israel who underwent transcatheter aortic valve implantation. Q fever infective endocarditis was diagnosed and treated in 4 (2.6%) patients; follow-up at a median 12 months after valve implantation indicated preserved prosthetic valvular function.     

Restriction endonuclease analysis of chromosomal DNA from Listeria monocytogenes strains

Restriction endonuclease analysis of chromosomal DNA was applied to thirteen Listeria monocytogenes strains alongside the more conventional typing methods of serotyping and phage typing. The organisms were isolated from cases of sporadic listeriosis (nine strains); from an occasional nosocomial cluster (two strains); and from food samples (two strains).Purified DNAs were digested with EcoRI restriction endonuclease, and restriction fragments separated by electrophoresis. Restriction patterns correlated well with phage patterns, but also allowed typing of the phage-untypable strains.DNA fingerprinting appears to be a potentially helpful tool for epidemiological investigations of listeric infections, particularly when phage typing fails to determine the identity or diversity of the isolates.     

Molecular and phage typing of Staphylococcus aureus harbouring cyrptic conjugative plasmids

The spread of antibiotic resistant -bacterial pathogens in a hospital could be due to the spread of a resistant strain or the spread of a resistance plasmid among unrelated strains. In this study the relatedness of Staphylococcus aureus isolates carrying identical cryptic conjugative plasmids was determined by a combination of resistance profiles, plasmid patterns, pulsed field gel electrophoresis of SmaI digested chromosomal DNA and phage typing. Results of the different typing techniques were in agreement to one another and demonstrated that the isolates were of three different types. The results suggested that a cryptic conjugative plasmid had spread to different S. aureus isolates in the hospital. This is an example of plasmid spread as opposed to strain spread.     

Rickettsioses studies. 3. Natural foci of rickettsioses in south Bohemia.

Antibodies against Coxiella burnetii and against rickettsiae of the spotted fever group were found in human sera and in sera from domestic and wild animals collected in south Bohemia. Spotted fever group rickettsiae were also discovered in the tick Ixodes ricinus. These results indicate the presence of both types of rickettsiae in this part of Czechoslovakia. As no epizootics or epidemics of Q fever have as yet been reported in the area, it can be assumed that C. burnetii occurs in the latent state. The occurrence of spotted fever group rickettsiae is probably endemic among I. ricinus ticks and among small and larger wild mammals.     

Ricettsioses studies. 2. Natural foci of rickettsioses in east Slovakia.

Natural foci of Q fever and of spotted fever group rickettsiae in the Košice district of east Slovakia are described and discussed. It was established that the natural focus of Q fever was a secondary one. Cattle were observed to be the main source of human infection and a high proportion of synanthropic rodents was found to be infested with Coxiella burnetii. The natural focus of spotted fever group rickettsiae was shown to be of a primary character, such rickettsiae circulating among ticks and small mammals. It is suggested that natural foci of spotted fever group rickettsiae in east Slovakia may be connected with the natural distribution of Dermacentor ticks.     

Plasmid deoxyribonucleic acid in throat and cerebrospinal fluid isolates of Neissepia meningitidis

Ten strains of Neisseria meningitides, isolated either from cerebrospinal fluid or from throat cultures, were typed and screened for the presence of plasmid DNA. Three group C strains, isolated in the same area, each harboured a plasmid of similar molecular weight (approx. 8.5 Md). No evidence of plasmid DNA was found in the other strains (whether of the same group but isolated in another area, or of other groups).Corresponding author.     

Rickettsioses studies. 1. Natural foci of rickettsioses in the Armenian Soviet Socialist Republic.

Ixodid ticks collected in the Armenian SSR during 1971 and 1974 were positive for rickettsiae of the spotted fever group, as confirmed by haemocyte tests and by isolation experiments. Serum specimens collected from human beings and from domestic and wild animals in the same areas contained antibodies against such rickettsiae and against Coxiella burnetii. These results indicate the existence of mixed natural foci of rickettsioses of the spotted fever group and of Q fever in the Armenian SSR.     

Ribosomal DNA fingerprinting of Listeria monocytogenes using a digoxigenin-labeled DNA probe

A nonisotopic ribosomal DNA fingerprinting technique was developed for the characterization of Listeria monocytogenes. Plasmid pKK3535 (a pBR322-derived plasmid containing rrnB ribosomal RNA operon of Escherichia coli) was labeled with digoxigenin-II-dUTP by random priming and used to probe EcoRI fragments of L. monocytogenes chromosomal DNA on nylon filters. The method was successfully applied to the characterization of two sets of patient and food isolates of L. monocytogenes.Corresponding author.     

Plasmid typing of Shigella sonnei epidemic strains and molecular relationship of their R-plasmids

We conducted a surveillance program on epidemic and/or endemic Shigella strains in Asturias (Spain), their frequency and dispersion in our community, and their R-plasmids. We analyzed initial isolates of Shigella sonnei from two epidemic outbreaks using antibiotic resistance patterns and plasmid profile analysis as epidemiological markers. We found that the 2 outbreaks were caused by different S. sonnei strains, which respectively carried one and two R-plasmids together with other plasmids. The molecular relationship among these and three other R-plasmids from two S. sonnei strains isolated during a previous outbreak, were studied by restriction enzyme analysis and DNA-DNA hybridizations. We were able to establish different levels of relationship among the six R-plasmids.Corresponding author.     

Epidemiology of rickettsial diseases

Rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. For the spotted fever group (SFG) rickettsiae, Rickettsia typhi. R. tsutsugamushi, Coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. All rickettsioses exist as zoonoses. Moreover, all rickettsiae are found in infected arthopods, which generally serve as the natural hosts and can transmit the infection to the next generation of ticks, mites, chiggers, or fleas. From our anthropocentric viewpoint, Q fever aerosol infection from parturient animals and Brill-Zinsser disease ignited epidemics of louse-borne epidemic typhus are exceptions. However, silent cycles of C. burnetii in ticks and R. prowazekii in the flying squirrel flea may have maintained these agents in transovarial or enzootic cycles for eons before humans and their domestic animals arrived on the scene. Thus, the epidemiology of rickettsial diseases must be recognized as an unfortunate aberration of the rickettsial economy.Several excellent reviews of rickettsial ecology contain a wealth of useful information (2, 8, 55, 70, 84).Presented at the 4th International Symposium on Riskettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Epidemiological typing of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is increasingly recognized as a cause of hospital-acquired infection and respiratory tract colonization in cystic fibrosis patients. A number of methods have been described for the typing of strains in epidemiological studies. Pulsed-field gel electrophoresis (PFGE) of total chromosomal DNA cleaved by low-frequency restriction site endonucleases (XbaI, SpeI) is highly discriminatory and defines populations at the strain level. Other molecular methods such as ribotyping with restriction endonucleases (BamHI, ClaI, BelI, EcoRI) can be used to subdivide the species but with reduced discrimination compared with PFGE. Polymerase chain reaction (PCR) fingerprinting techniques utilizing random primers or those directed against repeat motifs (ERIC, REP) are rapid and offer high discrimination for the study of outbreaks. A consistent finding from a number of incidents is the high diversity of strain types of S. maltophilia identified and the low incidence of cross-infection between patients.     

宏基因组二代测序技术辅助诊断中枢神经系统贝氏柯克斯体感染性血管炎1例

Q热是由贝氏柯克斯体感染引起的人畜共患病,临床表现多样且无特异性,贝氏柯克斯体颅内感染罕见,经常被误诊和漏诊,导致部分患者预后不佳。此文报告1例宏基因组二代测序(mNGS)技术辅助诊断的中枢神经系统贝氏柯克斯体颅内感染性血管炎病例,提示mNGS技术在Q热快速诊断中起到重要作用,通过早期诊断,精准治疗,明显改善患者预后。在此基础上回顾国内外相关文献,总结贝氏柯克斯体颅内感染的临床表现和诊治经验,供国内外同行参考。     

Plasmid profiles of legionella pneumophila strains isolated in Spain

An assay for plasmid DNA content was carried out in 100 strains of Legionella pneumophila of distinct serogroups and isolated from various sources (clinical, environment). The strains were isolated from different geographic regions in our country. The presence of plasmids was proved in one of the 11 clinical isolates and in 68 of the 89 isolated of environmental origin studied. In the strains belonging to serogroup 1 and isolated in our region (Cantabria), three plasmid profiles were observed, whereas in strains of the same serogroup from other geographic regions, two profiles were shown which exhibited differences compared to the former ones. Analysis by means of restriction endonucleases suggested that plasmids of similar size in serogroup 1 strains of different source, were related. The results obtained do not appear to reveal any correlation between plasmid profile and source of isolation or serogroup.Corresponding author.     

斑点热群立克次体HN-98株的分离和初步鉴定

目的 从海南省斑点热疫源地不明热病人体内分离斑点热群立克次体。方法 用鸡胚卵黄囊培养法直接从斑点热疫区一不明热病人血标本中分离立克次体,继之用分子生物学及血清学试验对分离株进行鉴定。结果 从海南省琼中县斑点热疫区一不明热男性民工的血标本中分离到了一株立克次体,命名为ＨＮ－９８株立克次体,西伯利亚种。结论 该结果进一步从病原学上证实海南省琼中县存在有斑点热疫源地。     

Pseudomonas aeruginosa clinical isolates: Serotypes, resistance phenotypes and plasmid profiles

78 Pseudomonas aeruginosa strains were isolated from the respiratory tract of 56 patients, 15 of which were affected by cystic fibrosis (CF). The epidemiological typing scheme was based on serotyping, antibiotic resistance pattern and plasmid DNA profile. All strains (except 2 mucoid strains) were typed using a rapid slide O-agglutination technique. Most common serotypes in both group were 0:1, 0:10 and 0:6. Moreover we observed a correlation among 0:12 serotype and CF patients. Plasmid DNA analysis showed that 45.2% (on average) of strains isolated from patients with and w/o CF harboured 1–3 plasmids ranging in size from 1 to 15 Md. Plasmid prevalence was higher in strains isolated from CF patients in specimens collected after antibiotic therapy. A correlation was found between 1 and 1.9 Md plasmids and resistance to aminoglycosides. Our results indicate that the analysis of antibiotic resistance phenotypes combined with plasmid analysis may be useful, in association to serotyping, to characterize the circulation of P. aeruginosa strains and the spread of resistance in these bacteria.