Posttraumatic Headache

Posttraumatic headaches are among the most challenging complaints after mild traumatic brain injury (mTBI). They are a debilitating problem experienced by patients after TBI of all severities. Up to 90% of mild TBI patients experience headache, particularly if female and with a premorbid history of primary headache. Tension headache has classically been the most common subtype, but in military populations migraine has dominated. Posttraumatic headache encompasses a spectrum of headache types that overlap heavily with common primary headache disorders, but also autonomic cephalgias as well as several secondary headache conditions. It is important to understand the evolution of postconcussion syndrome as a concept, and the challenges associated with diagnosing and treating multidomain drivers effectively. The first-line treatments for posttraumatic headache are typically the same as those used in nontraumatic headache, with additional considerations for cognitive side effects, posttraumatic epilepsy, and coexisting injuries resulting in neuropathic pain or medication overuse.

Variation in TMEM106B in chronic traumatic encephalopathy

The genetic basis of chronic traumatic encephalopathy (CTE) is poorly understood. Variation in transmembrane protein 106B (TMEM106B) has been associated with enhanced neuroinflammation during aging and with TDP-43-related neurodegenerative disease, and rs3173615, a missense coding SNP in TMEM106B, has been implicated as a functional variant in these processes. Neuroinflammation and TDP-43 pathology are prominent features in CTE. The purpose of this study was to determine whether genetic variation in TMEM106B is associated with CTE risk, pathological features, and ante-mortem dementia. Eighty-six deceased male athletes with a history of participation in American football, informant-reported Caucasian, and a positive postmortem diagnosis of CTE without comorbid neurodegenerative disease were genotyped for rs3173615. The minor allele frequency (MAF = 0.42) in participants with CTE did not differ from previously reported neurologically normal controls (MAF = 0.43). However, in a case-only analysis among CTE cases, the minor allele was associated with reduced phosphorylated tau (ptau) pathology in the dorsolateral frontal cortex (DLFC) (AT8 density, odds ratio [OR] of increasing one quartile = 0.42, 95% confidence interval [CI] 0.22–0.79, p = 0.008), reduced neuroinflammation in the DLFC (CD68 density, OR of increasing one quartile = 0.53, 95% CI 0.29–0.98, p = 0.043), and increased synaptic protein density (β = 0.306, 95% CI 0.065–0.546, p = 0.014). Among CTE cases, TMEM106B minor allele was also associated with reduced ante-mortem dementia (OR = 0.40, 95% CI 0.16–0.99, p = 0.048), but was not associated with TDP-43 pathology. All case-only models were adjusted for age at death and duration of football play. Taken together, variation in TMEM106B may have a protective effect on CTE-related outcomes.

Lewy Body Pathology and Chronic Traumatic Encephalopathy Associated With Contact Sports

Traumatic brain injury has been associated with increased risk of Parkinson disease and parkinsonism, and parkinsonism and Lewy body disease (LBD) can occur with chronic traumatic encephalopathy (CTE). To test whether contact sports and CTE are associated with LBD, we compared deceased contact sports athletes (n = 269) to cohorts from the community (n = 164) and the Boston University Alzheimer disease (AD) Center (n = 261). Participants with CTE and LBD were more likely to have β-amyloid deposition, dementia, and parkinsonism than CTE alone (p < 0.05). Traditional and hierarchical clustering showed a similar pattern of LBD distribution in CTE compared to LBD alone that was most frequently neocortical, limbic, or brainstem. In the community-based cohort, years of contact sports play were associated with neocortical LBD (OR = 1.30 per year, p = 0.012), and in a pooled analysis a threshold of >8 years of play best predicted neocortical LBD (ROC analysis, OR = 6.24, 95% CI = 1.5-25, p = 0.011), adjusting for age, sex, and APOE ɛ4 allele status. Clinically, dementia was significantly associated with neocortical LBD, CTE stage, and AD; parkinsonism was associated with LBD pathology but not CTE stage. Contact sports participation may increase risk of developing neocortical LBD, and increased LBD frequency may partially explain extrapyramidal motor symptoms sometimes observed in CTE.

Potential donor families' experiences of organ and tissue donation-related communication, processes and outcome

We aimed to describe the experiences of families of potential organ and tissue donors eligible for donation after circulatory death or brain death. Forty-nine family members of potential donors from four Melbourne hospitals were interviewed to assess their experiences of communication, processes and the outcomes of donation. Interviews were recorded, transcribed verbatim and analysed thematically. Families expressed a range of perspectives on themes of communication, hospital processes and care, the processes of consent and donation and reflected on decisions and outcomes. They expressed satisfaction overall with communication when receiving bad news, discussing death and donation. Honest and frank communication and being kept up-to-date and prepared for potential outcomes were important aspects for families, especially those of post circulatory death donors. Participants reported high levels of trust in healthcare professionals and satisfaction with the level of care received. Many donor families indicated the process was lengthy and stressful, but not significantly enough to adversely affect their satisfaction with the outcome. Both the decision itself and knowing others' lives had been saved provided them with consolation. No consenting families, and only some non-consenting families, regretted their decisions. Many expressed they would benefit from a follow-up opportunity to ask questions and clarify possible misunderstandings. Overall, while experiences varied, Australian families valued frank communication, trusted health professionals, were satisfied with the care their family member received and with donation processes, despite some apparent difficulties. Family satisfaction, infrequently assessed, is an important outcome and these findings may assist education for Australian organ donation professionals.

Effect of arsenite on induction of CYP1A and CYP2H in primary cultures of chick hepatocytes

In earlier studies, treatment with sodium arsenite was shown to decrease total hepatic CYP in rats. A concomitant increase in heme oxygenase, the rate-limiting step in heme degradation to biliverdin, was considered responsible for the decrease in CYP. Here we investigated the effect of sodium arsenite on induction of CYP2H, CYP1A, and heme oxygenase in primary cultures of chicken embryo hepatocytes. When added simultaneously with inducer, arsenite inhibited phenobarbital-mediated increases in CYP2H and 3-methylcholanthrene-mediated increases in CYP1A, as measured enzymatically and immunochemically. Near maximal decreases were observed in these forms of CYP at a concentration of 2.5 microM sodium arsenite. The concentration-dependent decreases in CYP2H and CYP1A by sodium arsenite were concomitant with increases in heme oxygenase. Sodium arsenite was not toxic at concentrations as high as 10 microM, as indicated by protein synthesis and the reduction of MTT by intact cells. Sodium arsenite had no effect on induction of CYP2H1 mRNA, suggesting that the decreases in this form of CYP occurred post-transcriptionally. Treatment of cells with tin mesoporphyrin (SnMeso), an inhibitor of heme oxygenase, resulted in inhibition of arsenite-induced heme oxygenase. However, SnMeso did not alter the effect of arsenite to prevent phenobarbital-mediated increases in CYP2H protein. SnMeso alone inhibited phenobarbital-mediated increases in CYP2H. Inclusion of 2 or 5 microM exogenous heme with arsenite did not prevent the arsenite-mediated decrease in CYP2H. Combined treatment with heme and phenobarbital induced heme oxygenase to the same extent as treatment with heme, arsenite, and phenobarbital. However, CYP2H activity was decreased only when the treatment included arsenite. These results suggest that elevated levels of heme oxygenase alone are not responsible for arsenite-mediated decreases in CYP2H.

Clinical experience and outcomes of community-acquired and nosocomial methicillin-resistant Staphylococcus aureus in a northern Australian hospital

Methicillin-resistant Staphylococcus aureus (MRSA) is a well-recognized cause of hospital-acquired sepsis. We reviewed the clinical features of a new variant of community-acquired MRSA originally described from the Kimberley region of northern Western Australia (WA MRSA). This strain has become an increasing cause of community- and hospital-acquired sepsis at Royal Darwin Hospital (RDH) in the Northern Territory, especially in Aboriginal Australians from remote communities. Fifty percent of WA MRSA was community-acquired, with 76% in Aboriginals. Like the MRSA from eastern Australia (EA MRSA), WA MRSA commonly caused skin sepsis but was less likely to cause respiratory or urinary infections compared with EA MRSA. Twelve out of 125 (9.6%) WA MRSA and 7/93 (7.5%) EA MRSA infections were septicaemias. Septicaemia due to WA MRSA occurred in adult medical patients, especially those with temporary haemodialysis catheters, while EA MRSA septicaemia occurred throughout the hospital. Aboriginal people were more likely to develop both community- and hospital-acquired WA MRSA septicaemia [overall relative risk (RR) 12.3 (95% CI 3.7-40.7)]. Control of WA MRSA requires policies to reduce transmission in both hospitals and communities. Community-based control programmes need support for individual patient management, improved housing and hygiene, control of skin sepsis and appropriate use of antibiotics, especially in rural Aboriginal communities in northern Australia.

Emerging epidemic of community-acquired methicillin-resistant Staphylococcus aureus infection in the Northern Territory

OBJECTIVE

To investigate the epidemiology of WA MRSA (the recently recognised Western Australian strains of methicillin-resistant Staphylococcus aureus) in the north of the Northern Territory (NT).

DESIGN

Retrospective survey of data from hospital records.

SETTING

Royal Darwin Hospital (a tertiary referral hospital that serves the north of the NT) between January 1991 and July 1995.

SUBJECTS

All inpatients with clinical MRSA infection.

OUTCOME MEASURES

Incidence of MRSA infection, classification of MRSA as WA or EA (Eastern Australian) based on antibiotic susceptibility, patient demographic details (age, sex, ethnicity, region of residence), source of infection (nosocomial or community-acquired).

RESULTS

There were 125 WA MRSA and 93 EA MRSA infections, comprising 7% of all S. aureus infections. The incidence of WA MRSA infections consistently increased, while that of EA MRSA initially fell and then increased. All EA MRSA infections were nosocomial, while 50% of WA MRSA infections were community-acquired. Rates of WA MRSA infections were highest in patients from the west region of the NT, adjacent to the Kimberley region of Western Australia (WA). Community-acquired WA MRSA infections were more likely to affect Aboriginals than non-Aboriginals (relative risk [RR], 25.86; 95% confidence interval [CI], 12.51-53.47, based on population data; RR, 15.43; 95% CI, 7.85-30.32, based on admission data), as were nosocomial EA MRSA infections (RR, 2.54; 95% CI, 1.44-4.47, based on population data; RR, 2.30; 95% CI, 1.52-3.46, based on admission data).

CONCLUSIONS

Changes in the epidemiology of MRSA infection in the north of the NT are consistent with the hypothesis that community-acquired WA MRSA spread into and across the NT from the Kimberley region of WA. Alternatively, crowded living conditions, hygiene difficulties and increasing use of broad spectrum antibiotics may have led to independent emergence of WA MRSA in both regions. Current infection control policies and their use in rural Aboriginal communities must be reassessed.

Genetic variation in Australian spotted fever group rickettsiae

Rickettsiae were isolated by cell culture of buffy coat blood from six patients with spotted fever from southeastern Australia and Flinders Island in Bass Strait. The isolates were genetically compared with two previous Rickettsia australis patient isolates. The genus-specific 17-kDA genes from the isolates were compared after DNA amplification and restriction fragment analysis of the amplified DNA. This comparison revealed that mainland rickettsial isolates from southeastern Australia were identical to two previous isolates of R. australis from northeastern Australia. Rickettsial isolates from Flinders Island were distinct from the mainland isolates. The 16S rRNA gene sequences from the isolates were determined and compared. The Flinders Island rickettsial agent was most closely related (0.3% structural divergence) to Rickettsia rickettsii, Rickettsia conorii, and Rickettsia slovaca. The Flinders Island rickettsial agent was 1.3 and 2.1% structurally divergent from R. australis and Rickettsia akari, respectively. The 16S rRNA gene sequence from the Flinders Island agent shows that this rickettsia is more closely related to the rickettsial spotted fever group than is R. australis. We conclude that there are two populations of spotted fever group rickettsiae in Australia and propose that the genetically distinct causative organism of Flinders Island spotted fever be designated Rickettsia honei. The extent of distribution and animal host reservoirs remain to be elucidated.

Chromoblastomycosis: a retrospective study of six cases at the Royal Darwin Hospital from 1989 to 1994

Chromoblastomycosis, a localized chronic cutaneous and subcutaneous infection of the skin caused by pigmented fungi, is most common in the world's tropical and subtropical zones. The condition rarely occurs in Australia. We present 6 cases of chromoblastomycosis seen at the Royal Darwin Hospital, Northern Territory, from 1989 to 1994 and affecting predominantly male Caucasians ranging from 38 to 71 yrs of age. Clinically the lesions were verrucous or nodular. They mimicked basal or squamous cell carcinoma, nevi or solar keratoses. Histopathologic findings were nonspecific. The only pathognomonic finding was the presence of brown spores or sclerotic bodies within granulomata or within microabscesses in the skin.

Cytotoxin production by Helicobacter pylori from patients with upper gastrointestinal tract diseases

A cytotoxin produced by some Helicobacter pylori strains has recently been identified. The cytotoxin induces intracellular vacuolization of cultured cells. The aim of the present study was to examine the frequency of occurrence of cytotoxin-producing strains of H. pylori from subjects with upper gastrointestinal disease including nonulcer dyspepsia, gastric and duodenal ulcer disease, gastroesophageal reflux disease, and gastric cancer. Broth culture filtrates of clinical isolates of H. pylori recovered from 175 patients were used to inoculate Vero and HeLa cell monolayers for the detection of vacuolating cytotoxin activity. The results obtained demonstrated that the highest percentage of strains producing cytotoxin were found in subjects with peptic ulcer disease (gastric ulcer, 65%; duodenal ulcer, 66%; P < 0.01 compared with nonulcer dyspepsia, 38%). Of the 11 patients with gastroesophageal reflux disease, 4 of 5 patients in this group who had esophageal ulcers, were found to be infected with strains that produced cytotoxin. Three of the four patients with carcinoma of the stomach were also found to be infected with cytotoxic strains of H. pylori. With increasing severity of mucosal damage in subjects with a normal upper gastrointestinal tract, macroscopic gastritis, duodenitis, and peptic ulceration, there were corresponding increase in the proportion of strains producing cytotoxin; these increases were 32, 46, 50, and 66%, respectively. H. pylori strains from subjects with ulcer disease commonly produced vacuolating cytotoxin, suggesting that it may be a virulence factor in the pathogenesis of peptic ulcer disease.

A pseudoepidemic of Mycobacterium chelonae: contamination of a bronchoscope and autocleaner

BACKGROUND

At fibreoptic bronchoscopy the potential exists for contamination of bronchoscopes and microbiological specimens. Patients may also be cross infected with acid fast bacilli (AFB). During a five month period, 12 bronchial wash specimens of 65 patients undergoing bronchoscopy, one bronchoscope and an autocleaner, were contaminated with the AFB, Mycobacterium chelonae (MCH).

AIM

To eradicate AFB contamination of bronchoscopy specimens by identifying sources of contamination and modifying disinfection procedures.

METHODS

To identify the source of contamination, samples for AFB culture were taken from three bronchoscopes, the autocleaner and water taps. To eradicate MCH contamination, the bronchoscopes were soaked in 2% glutaraldehyde overnight and flushed with 70% alcohol. Disinfection procedures were altered by using sterile water and containers in cleaning. Autocleaner use was discontinued.

RESULTS

The autocleaner, one bronchoscope and 12 bronchial wash specimens were contaminated with MCH. All contaminants had similar electrophoretic banding on probing of their DNA fragments, suggesting a common clone of origin. After the alterations in disinfection procedures and despite prolonged soaking in 2% glutaraldehyde, three further contaminated wash specimens were isolated from one bronchoscope. Only after ethylene oxide sterilisation of this bronchoscope was the contamination overcome. Since then no further MCH contamination has occurred. No patient required treatment and there has been no clinical evidence of mycobacterial disease.

CONCLUSION

To avoid contamination of bronchoscopy specimens with MCH, use of autoclearners should be discouraged and sterile water and containers used in cleaning procedures. If MCH contamination occurs in this setting, the bronchoscope and dismantled valve mechanism should undergo ethylene oxide sterilisation.

Comparison of Pneumocystis carinii detection by toluidine blue O staining, direct immunofluorescence and DNA amplification in sputum specimens from HIV positive patients

Pneumocystis carinii pneumonia (PCP) is the commonest opportunistic infection in AIDS patients. By using the polymerase chain reaction (PCR), specific DNA sequences can be amplified and used in diagnosis of infections such as PCP where the causative pathogen is both difficult to grow and present in low numbers. Twenty HIV positive patients were investigated for PCP. Twenty sputa (15 induced and 5 expectorated) had toluidine blue O staining, direct immunofluorescence and PCR performed for Pneumocystis carinii in a blinded fashion. PCR was performed using primers pAZ102-E 5' GATGGCTGTTTCCAAGCCCA 3' and pAZ102-H 5' GTGTACGTTGCAAAGTACTC 3' from the gene coding for Pneumocystis carinii mitochondrial ribosomal RNA with a specific 346 base-pair sequence being amplified from positive specimens. Ten of the patients had Pneumocystis carinii shown by conventional tests and PCR. Another 3 patients were positive only by PCR, all had evidence of infection with Pneumocystis carinii; the first was positive by subsequent conventional stains, the second was treated for bacterial bronchitis but had a non-resolving chest infection with PCP found on postmortem after 4 mths, the third had a typical interstitial infiltrate on CXR and responded to empiric PCP treatment. PCR is more sensitive than toluidine blue O staining and direct immunofluorescence in detecting Pneumocystis carinii in sputum from HIV patients and may become the diagnostic method of choice for PCP.

A new trichrome-blue stain for detection of microsporidial species in urine, stool, and nasopharyngeal specimens

Detection of microsporidia in clinical specimens has relied on electron microscopy, histology, or staining. This article describes further alterations to the modified trichrome staining method which make it easier to identify microsporidial spores. The changes are a decrease in the phosphotungstic acid level and the substitution of a colorfast counterstain, aniline blue, for the fast green of the original stain. The modified stain provides good contrast between microsporidial spores and background material including human and fungal cells. Stool specimens from 139 human immunodeficiency virus-seropositive patients revealed that 5 patients were infected with Enterocytozoon bieneusi and 6 patients had larger spores. Thin-section electron microscopy of the larger spores showed a structure consistent with that of either Encephalitozoon or Septata species. Three of the patients with Encephalitozoon- or Septata-like species had disseminated infection, with spores detected in nasopharyngeal aspirates and urine samples.

The epidemiology of tuberculosis in Victoria

AIMS

To describe the epidemiology of Mycobacterium tuberculosis (MTb) in Victoria, Australia.

METHODS

We analysed data from the Victorian Mycobacterium Reference Laboratory database and MTb notifications to Health and Community Services Victoria, for the period 1948 to 1992.

RESULTS

The annual number of notified tuberculosis cases peaked at 1143 in 1954 and declined to 266 in 1992. The incidence rate decreased from 47 to 6.2 per 100,000 in the same period. The pattern of tuberculosis has changed significantly over the last two decades, reflecting the high prevalence of MTb in recent immigrants, particularly in those from South-East Asia. Among people born overseas the number of cases increased from 40% of notifications in 1970 to 80% in 1990; they are younger, more likely to be female and to have extrapulmonary disease, than their Australian-born counterparts. Between 1987 and 1991, the mean annual incidence of tuberculosis in people born in Australia and South-East Asia respectively was 1.5 and 47.5 per 100,000. People born in Vietnam, Cambodia and the Philippines had rates between 100 and 400 per 100,000. These rates have remained stable during the last six years. Almost 50% of migrant patients presented within five years, and 30% within two years, of arrival in Australia. The estimated mean annual incidence of MTb in homeless men between 1984 and June 1992 was 80 per 100,000. Resistance to all first-line drugs increased from 10.8% of all isolates in 1981 to 14.7% in 1990. The incidence of multi-drug resistant MTb (MDR-MTb) has been consistently less than 2% of isolates per year in the past 15 years. There were 14 cases of MTb and HIV between 1985 and June 1992. The mean annual incidence of MTb in people with AIDS is 1579 per 100,000 (range, 570-2420 per 100,000), with a relative risk of 236 (95% confidence interval [CI], 134-414). MDR-MTb has not been documented in HIV-infected individuals in Victoria.

CONCLUSION

Tuberculosis remains an important public health concern. Groups at high risk include people born overseas, the homeless, and people infected with HIV. Physicians caring for AIDS patients should consider the diagnosis of MTb, since its incidence in AIDS patients is so high. Our data suggest possible shortcomings in current methods of screening and prophylactic treatment of migrants and refugees. The rising rate of drug resistance cannot be ignored. We should consider strategies to ensure judicious use of anti-tuberculous drugs by physicians, and optimal patient compliance. These issues are critical to the future of tuberculosis control in Victoria.

Isolation of a DNA probe for identification of Mycobacterium kansasii, including the genetic subgroup

In order to develop a DNA-based assay to identify all Mycobacterium kansasii clinical isolates, a specific DNA probe was isolated in plasmid p6123. A total of 145 M. kansasii clinical isolates were collected from several countries and were examined with three probes by DNA hybridization. Of the 145 isolates, 115 (79%) were positive with the previously described probe pMK1-9 (Z. H. Huang, B. C. Ross, and B. Dwyer, J. Clin. Microbiol. 29:2125-2129, 1991), 129 (88%) were positive with the commercial Accu-probe assay (Gen-Probe), and 145 (100%) were positive with the p6123 probe. Southern blot analysis of EcoRI-digested M. kansasii chromosomal DNA with p6123 revealed that all Accu-probe-positive M. kansasii strains exhibited a 3-kb fragment, whereas all Accu-probe-negative M. kansasii strains displayed DNA fragments of variable molecular sizes. These results indicate that, unlike the previously described probes for M. kansasii, the fragment cloned into p6123 identified all 145 biochemically typical strains tested and provides an ideal target for future DNA-based speciation assays.

A new focus of scrub typhus in tropical Australia

A new focus of scrub typhus (Rickettsia tsutsugamushi) is described in a remote rain forest region of the Northern Territory of Australia. Five serologically confirmed cases, two near fatal with multisystem involvement, have occurred since the area became accessible to tourists. As tourism increases, other remote foci of vectors and organisms may also be recognized in tropical Australia.

Identification of an insertion sequence-like element in a subspecies of Mycobacterium kansasii

Analysis of a genomic DNA clone library of a strain from the genetic subspecies of Mycobacterium kansasii determined the existence of a repetitive insertion sequence-like element. The element is 947 bp long and is present in a minimum of 1 to 11 copies per genome. Similar to insertion sequences, it contains a 3-bp (TAG) direct repeat at its extremities and a transcription promoter-like sequence. In addition, for one of the clones sequenced, a potential cointegrate formation, a characteristic frequently observed with insertion sequences, was revealed. This insertion sequence does not contain short inverted repeats near the ends or a large open reading frame to code for a transposase enzyme. Its host range is restricted to a previously described genetic subspecies of M. kansasii and is not present in typical M. kansasii or other mycobacterial species. When used as a probe for Southern blot hybridization, significant heterogeneity between different isolates of the M. kansasii subspecies was observed. This repeated element will be useful in further studies on the characterization, diagnosis, and epidemiology of M. kansasii.

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.

Comparative evaluation of detection assays for Chlamydia trachomatis

The performances of a commercial nucleic acid hybridization test (Gen-Probe Pace 2 Chlamydia trachomatis) and two commercial enzyme immunoassays (EIAs) (Abbott Chlamydiazyme and Pharmacia Chlamydia EIA) were evaluated against cell culture for the detection of C. trachomatis infection, with cervical swabs obtained from 1,037 women visiting a public sexual health center. The positivity rate by cell culture was 4.7%. Sensitivity and specificity for each test were as follows: Gen-Probe, 95.8 and 98.3%; Chlamydiazyme, 80.4 and 99.3%; Pharmacia EIA, 80.8 and 99.1%. Analysis of discrepant results with probe confirmation assay (Gen-Probe) and direct immunofluorescence (Syva Microtrak) revealed 12 cases of C. trachomatis infection for which culture was negative, resulting in the definition of a true-positive case as opposed to a culture positive. The positivity rate by true-positive definition was 5.9%, and sensitivity and specificity for each test were as follows: Gen-Probe, 96.7 and 99.6%; Chlamydiazyme, 77.5 and 100%; Pharmacia EIA, 77.0 and 100%; cell culture, 80.0 and 100%. We conclude that the Gen-Probe Pace 2 C. trachomatis test is a sensitive and specific alternative to cell culture for the detection of C. trachomatis.