Preventing Q fever endocarditis: a review of cardiac assessment in hospitalised Q fever patients.

INTRODUCTION: Acute Q fever is an important zoonotic disease in some parts of rural Australia. Q Fever can lead to chronic disease such as endocarditis, this complication occurring more commonly in patients with underlying heart valve pathology or an impaired immune system. Untreated Q fever endocarditis has a high mortality rate, but even with appropriate therapy, 10% of patients will die. Cardiac assessment can identify patients at risk. The aim of this review was to examine recorded cardiac assessment of hospitalised Q fever patients within the regional area of Hunter New England (HNE), New South Wales (NSW). METHODS: Medical records of patients with Q fever admitted to hospitals in HNE during the period 2005-2009 were identified through the NSW Notifiable Diseases Database and the NSW Inpatient Statistics Collection. A standardised medical record review tool was used to undertake the review. RESULTS: Eighty-nine records were reviewed. Over 50% of patients were admitted to a district hospital staffed by local GPs. Cardiac assessment was not routinely documented and for 91% there was no record of a cardiac history being taken. Approximately 25% had no record of a cardiac physical examination and only 6 cases had a record of a complete cardiac examination. CONCLUSION: Q Fever remains an important disease in some parts of rural Australia. Q Fever endocarditis is a serious sequel to acute Q fever and underlying heart valve pathology. Due to its indolent progression and poor outcome when diagnosis is delayed, a thorough cardiac assessment of all patients with suspected or confirmed Q fever is important. The level of documentation of cardiac assessment for Q fever patients is of concern because it may indicate cardiac assessments were not performed. General practitioners, especially in rural and regional areas, are encouraged to conduct cardiac assessments for all patients with acute Q fever to identify patients at risk of developing Q fever endocarditis.

A comparison of methods for extracting DNA from Coxiella burnetii as measured by a duplex qPCR assay.

AIMS: To determine the optimal DNA extraction method for the detection of Coxiella burnetii including the small-cell variant (SCV) by real-time PCR (qPCR) in clinical samples. METHODS AND RESULTS: A duplex qPCR detecting two Coxiella burnetii gene targets (com1 and IS1111a genes) was developed. Each target in this PCR had a sensitivity of one copy number per reaction. DNA extraction methods were compared on spiked negative samples and included a silica column kit, a chloroform separation prior to a silica column method and a chloroform/phenol separation and DNA precipitation method. CONCLUSIONS: The silica column extraction method was more efficient at recovering C. burnetii DNA, from large-cell and small-cell variants, than a chloroform or chloroform/phenol method. The silica column method was useful on spiked human samples including serum, buffy coat and bone marrow samples. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrated that a simple column kit method is efficient to use for the detection of C. burnetii in clinical samples including the SCV.

Evaluation of a commercially available recombinant-protein enzyme-linked immunosorbent assay for detection of antibodies produced in scrub typhus rickettsial infections.

The 56-kDa major outer membrane protein antigen of Orientia tsutsugamuchi is the immunodominant antigen in human scrub typhus (ST) infections. An enzyme-linked immunosorbent assay (ELISA) using a recombinant 56-kDa protein (r56) to detect specific immunoglobulin M (IgM) produced in ST infections was developed, and its performance was evaluated using sera from patients with active ST (n = 59), spotted fever (SF) (n = 31), and murine typhus (MT) (n = 6) and from those without rickettsial infection (n = 52). The r56 ELISA was compared to an ELISA using native whole cell lysate of O. tsutsugamushi Karp or O. tsutsugamushi Gilliam as antigens. The performance of the assays using r56 was similar to that of those using native antigens. Using indirect immunoperoxidase (IIP) as the reference test, sensitivities were 86, 88, and 88% while specificities were 84, 90, and 87% in the three assays. Furthermore, cross-reactivity in confirmed cases of SF and MT was low (5.4, 2.7, and 2.7% respectively). The additional use of IgG in the r56 ELISA gave improved performance (sensitivity, 80%; specificity, 96%; cross-reactivity in SF and MT, 2.7%). The detection of high levels of IgG in some IgM-negative patients illustrates the importance of including a test for IgG in the detection of secondary or reactivated infections, since many of these patients were from regions in Thailand where these infections are endemic.

New Orientia tsutsugamushi strain from scrub typhus in Australia.

In a recent case of scrub typhus in Australia, Orientia tsutsugamushi isolated from the patient's blood was tested by sequence analysis of the 16S rDNA gene. The sequence showed a strain of O. tsutsugamushi that was quite different from the classic Karp, Kato, and Gilliam strains. The new strain has been designated Litchfield.

Spotted fever group rickettsial infection in south-eastern Australia: isolation of rickettsiae.

Flinders Island spotted fever (FISF), a spotted fever group (SFG) rickettsial disease first described in 1991, occurs in south-eastern Australia. The isolation of the aetiological agent is described for the first time having been obtained from the blood of two patients. An additional 22 cases are also reported. Of these patients four had positive initial serology, and 20 showed seroconversion (using Rickettsia australis as antigen). Acute phase blood specimens taken from seven patients caused neonatal mice to seroconvert to R. australis and a blood specimen from one of these patients (and one other) yielded rickettsiae. A field survey for possible reservoir and vector animals on Flinders Island, Tasmania and in Gippsland, Victoria (both in south-eastern Australia) yielded 217 vertebrates and 1445 invertebrate ectoparasites, mostly ticks. Ixodes cornuatus from humans and dogs in Gippsland produced seroconversion to SFG rickettsia when inoculated into mice but no invertebrate pools from Flinders Island produced seroconversion in mice. Haemolymph from an individual I. cornuatus removed from a human in Gippsland, yielded a SFG rickettsia on tissue culture. Sera from several species of native vertebrates, especially the bush rat, Rattus fuscipes, were positive for antibodies to SFG rickettsia.

A case of murine typhus in Queensland.

OBJECTIVE: To present a case of murine (endemic) typhus, the first to be reported within the last 30 years in Australia. CLINICAL FEATURES: A 17-year-old pregnant woman presented with a viral-like illness and later developed a spotted rash, fever and headache. INVESTIGATION AND OUTCOME: Sera taken on Day 7 and Day 30 of the illness showed seroconversion to Proteus OX19 (Weil-Felix) and to Rickettsia typhi (by immunofluorescence), indicating recent infection with Rickettsia of the typhus group. Her illness was clinically compatible with murine typhus. She responded well to erythromycin and delivered a normal infant at term. CONCLUSION: Infection with Rickettsia typhi (murine typhus) still occurs in Australia. It can be diagnosed by means of specific serological tests for rickettsial disease, which are superior to the non-specific Weil-Felix test.

Specific syphilis serological tests may become negative in HIV infection.

The diagnosis of syphilis is frequently dependent upon the results of serological tests, but the reliability of syphilis serology in patients with HIV-1 infection has been questioned. We examined specific antibody to Treponema pallidum (TP) using the TP haemagglutination (TPHA) and fluorescent treponemal antibody-absorption (FTA-ABS) tests in AIDS patients and HIV-antibody-negative controls with a history of syphilis. Tests were carried out on two sera separated by an interval of at least 3 years from each patient. Twelve out of 29 AIDS patients compared with four out of 29 controls showed significant falls in titres of specific antibody as measured by the TPHA, FTA-ABS, or by both the TPHA and FTA-ABS (P = 0.02). Furthermore, in three out of 29 (10%) of the AIDS patients with past syphilis infections both the TPHA and FTA-ABS became non-reactive. We conclude that negative specific serology does not exclude a past syphilis infection in patients with AIDS.

Flinders Island spotted fever: a newly recognised endemic focus of tick typhus in Bass Strait. Part 2. Serological investigations.

Twenty-six cases of a spotted-fever-like illness have been identified on Flinders Island, Tasmania, over a 17 year period. These patients and 335 healthy persons from the island were investigated serologically using the Weil-Felix agglutination test (Proteus sp. antigens OX2, OX19, OXK) and rickettsia-specific microimmunofluorescence. The antigens used in these latter tests comprised one member of the typhus group (Rickettsia typhi) and three members of the spotted fever group (Rickettsia rickettsii, Rickettsia australis and Rickettsia conorii). Patients with Flinders Island spotted fever showed a higher prevalence of positive reactions to the Weil-Felix tests (with OX2 and OX19 antigens) and a higher prevalence of positive results to rickettsia-specific serological tests (with the exception of antibodies to Rickettsia typhi) than did healthy persons; OX2 (36% v. less than 1%); OX19 (36% v. less than 1%); Rickettsia rickettsii (42% v. 1%); Rickettsia australis (46% v. 1%); Rickettsia conorii (42% v. 1%); Rickettsia typhi (4% v. 4%). In seven of the 26 patients (27%) seroconversion was demonstrated by means of Weil-Felix tests, confirming recent infection. In six of these patients seroconversion was also demonstrated in rickettsia-specific tests. Although these results support the clinical evidence that the illness on Flinders Island is caused by a rickettsia of the spotted fever group, the aetiological agent remains to be isolated.

Spotted fever in East Gippsland, Victoria: a previously unrecognised focus of rickettsial infection.

A new focus of spotted fever group rickettsial infection has been recognised in East Gippsland, Victoria. Seven cases have been identified among Melbourne residents after they holidayed in the area. The infections were confirmed serologically. The precise identity of the Rickettsia has not been determined.

Polyanions in syphilis: evidence that glycoproteins and macromolecules resembling glycosaminoglycans are synthesised by host tissues in response to infection with Treponema pallidum.

We investigated by means of radiolabelled precursors the source and nature of the polyanionic macromolecules present in rabbit tissues during active syphilis infection. Previous studies indicated that Treponema pallidum itself does not synthesise glycosaminoglycans, at least in vitro. In replicate experiments on unilaterally infected rabbits, tissue from the orchitic testis incorporated two to three times more 35S-sulphate and 3H-glucosamine (on a wet weight basis) than tissue from the non-orchitic contralateral testis. Incorporation of 35S-sulphate was independent of the number of viable T pallidum organisms present in the infested tissue, which suggested that incorporation represented biosynthesis by the host and not the treponeme. Testes from syphilitic rabbits two days after treatment with high doses (100 mg/kg) of penicillin incorporated less 35S-sulphate than untreated infected testes, but more than normal uninfected rabbit testes. This suggests that active syphilitic infection was necessary for maximum biosynthesis of the macromolecule(s) by host tissue. Hydrodynamic profiles showed incorporation of radiolabelled precursors into two distinct fractions of different sizes, which may represent a proteoglycan and a sulphated glycoprotein. Alcian blue staining of syphilitic testes at or after peak orchitis showed focal deposition of newly synthesised polyanionic components during peak orchitis and a more generalised fibrosis in testes after peak orchitis.

Treponema pallidum does not synthesise in vitro a capsule containing glycosaminoglycans or proteoglycans.

Treponema pallidum was investigated for its ability to synthesise glycosaminoglycans or proteoglycans in vitro. Isolated viable T pallidum organisms were incubated with radiolabelled precursors of glycosaminoglycans, sodium 35S-sulphate and 3H-glucosamine (tritiated glucosamine). T pallidum failed to incorporate sodium 35S-sulphate but did incorporate 3H-glucosamine into a macromolecule which may be associated with the surface of the treponeme. This macromolecule was resistant to degradation by specific glycosaminoglycanases. We conclude that T pallidum does not synthesise a capsule containing glycosaminoglycans in vitro.

Effects of anaerobic and microaerophilic conditions of extraction and incubation on the survival of Treponema pallidum in vitro.

Treponema pallidum extracted from infected rabbit testes under anaerobic conditions survived longer in vitro than those extracted under aerobic conditions. Anaerobically extracted treponemes were incubated anaerobically for 0, 12, 24, 36, or 48 hours and then exposed to microaerophilic conditions (3% oxygen) for further incubation. Treponemes transferred to microaerophilic conditions after 36 or 48 hours' anaerobic incubation maintained significantly greater viability compared with those kept under constant microaerophilic conditions, although there was no difference after 12 or 24 hours. T pallidum incubated under constant anaerobic conditions, however, usually maintained greater viability than those kept under constant microaerophilic conditions. These results suggest that T pallidum is sensitive to oxygen toxicity both during initial extraction from orchitic rabbit testes and subsequent incubation in vitro. In the latter case, it can be partially protected by a period of anaerobic incubation in vitro, before exposure to microaerophilic conditions.