[Mycoplasma pneumoniae and Chlamydophila pneumoniae coinfection in severe pneumoniae among a hospitalized child with respiratory distress: what are the best diagnostic tools for an optimal care?]

The role for Mycoplasma pneumoniae and Chlamydophila pneumoniae in lower and upper respiratory tract infections in childhood increased by use of specialised diagnostic techniques, more and more performant for the early diagnosis of these infections. However, the prevalence of M. pneumoniae and C. pneumoniae as a cause of severe pneumoniae among hospitalized children has been rarely described. We report a case of M. pneumoniae et C. pneumoniae coinfection in a 10-year-old child hospitalized with a respiratory distress.

Census and analysis of persistent false-negative results in serological diagnosis of human immunodeficiency virus type 1 group O infections

Human immunodeficiency viruses (HIV) have a high level of genetic diversity. The outlier variants of HIV type 1 (HIV-1) group O are distantly related to HIV-1 group M. Their divergence has an impact on serological diagnosis, with a risk of false-negative results. In this study, we report 20 failure cases, involving patients with primary or chronic infection, in France and Cameroon between 2001 and 2008. Our results indicate that some assays detected group O infection much less efficiently than others. Two major reasons for these false-negative results were identified: the presence or absence of a group O-specific antigen (and the designed sequence) for the detection of antibodies and the greater envelope variability of group O than of group M strains. This study highlights the complexity of screening for these divergent variants and the need to evaluate test performance with a large panel of strains, due to the extensive diversity of group O variants.

[Assessment of human papillomavirus testing on liquid-based Cyto-screen system for women with atypical squamous cells of undetermined significance. Effect of age]

OBJECTIVE

Analyse the performance of human papillomavirus testing with hybrid capture II on liquid-based CYTO-screen system for women diagnosed with atypical squamous cells of undetermined significance according to the age.

PATIENTS AND METHODS

Were included all women diagnosed with atypical squamous cells of undetermined significance for whom human papillomavirus testing was performed and cytological and histological procedures were available over a follow-up period of 6 to 18 months.

RESULTS

Human papillomavirus testing was performed in 3,047 patients, and results were compared to cytological and histological follow-up diagnosis in 1,880 cases (61.7%). The sensitivity for diagnosing cervical intraepithelial neoplasia was 93.3% in women less than 30 of age and 89.7% in women more than 30 of age. Specificity was 44.9% in women less than 30 of age and 64.4% in women more than 30 of age. Likelihood ratios confirmed these results as they show a low discriminatory power in case of positive result specifically in women less than 30 of age but an excellent performance in case of negative result.

DISCUSSION AND CONCLUSION

The use of human papillomavirus testing after a diagnosis of atypical squamous cells of undetermined significance with the residual material of Cyto-screen system is a possible triage procedure to identify patients needing a colposcopy. Its specificity is better for women over 30.

Comparaison de deux techniques d’hybridation moléculaire dans l’identification de mycobactéries en pratique courante

AIM OF THE STUDY

To evaluate the performance of two commercial methods for identification of Mycobacterium species: InnoLiPA Mycobacteria first version (Innogenetics) versus Genotype MTBC and Genotype Mycobacterium (HAIN) on, respectively, 2123 and 2164 distinct isolates.

MATERIALS AND METHODS

Both techniques are based on the reverse hybridization of PCR products to their complementary probes immobilized on membrane strips. The InnoLiPA assay targets the 16S-23S rRNA spacer region. The HAIN test is composed of two kits: Genotype MTBC, for identification of tuberculosis complex mycobacteria, is based on gyrB DNA sequence polymorphism. Genotype Mycobacterium kit targets the 23S rDNA for identification of mycobacteria other than tuberculosis (MOTT) and tuberculosis complex mycobacteria. Both assays identify complex tuberculosis mycobacteria and respectively, eight and 12 species of MOTT. Moreover, the Genotype MTBC allows species differentiation within the M. tuberculosis complex.

RESULTS

Eighty-eight percent and 95% of mycobacteria were identified by InnoLiPA and HAIN, respectively. Hybridization remained negative for 11% of isolates with InnoLiPA and 4% with HAIN. An identification of MOTT was obtained by conventional identification in all cases after the use of InnoLiPA. MOTT and one M. tuberculosis was obtained after HAIN procedure. Unidentified species were complementary to a specific probe in 5% of the cases with InnoLiPA and 17% with HAIN.

CONCLUSION

HAIN identifies more mycobacteria species than does InnoLiPA and allows identification in the M. tuberculosis complex. However, failure in identification occurs only with MOTT with InnoLiPA when one M. tuberculosis was found among mycobacteria non identified with HAIN.

Performance of TRUGENE hepatitis C virus 5' noncoding genotyping kit, a new CLIP sequencing-based assay for hepatitis C virus genotype determination

The performance of the recently developed, standardized direct sequencing assay for hepatitis C virus (HCV) genotyping [TRUGENE HCV 5'-NC (noncoding)] was assessed in comparison with the reverse hybridization-based assay INNO-LIPA HCV II. Both assays allow HCV genotyping starting from amplification products generated by the diagnostic Roche AMPLICOR HCV test. HCV amplicons from 205 patients were used for this study: 34 were tested prospectively by both methods, while 171 had been stored at -20 degrees C for up to 2 years after LiPA genotyping. The TRUGENE procedure failed to determine a genotype in six low-titered samples (3.5 +/- 0.3 log UI/mL vs. 5.2 +/- 0.5 UI/mL for typable samples). Type and subtype could be determined by sequencing for 199 samples (97%). Among them, five were considered as coinfections by the LiPA method. Three LiPA patterns suggesting type 1 and 4 coinfection were not supported by sequence analysis while one 1a/2b and one 1a/3a coinfection was backed up by direct sequencing. For the remaining 194 samples, type assignment was concordant in 100% of the cases. LiPA subtyping was available for 162 samples (83.5%). Sub-typing results concurred in 128 cases (79%). NS5B sequencing of discrepant samples underscored the limitation of the 5'-noncoding region (NCR) in correct subtype assignment. In conclusion, the TRUGENE HCV 5'-NC genotyping kit appeared to be a specific and reliable method that can be used in the current indication of HCV genotyping.

Cervical squamous intraepithelial lesions in HIV-infected women: prevalence, incidence and regression. European Study Group on Natural History of HIV Infection in Women

OBJECTIVES

To assess the impact of HIV-related immunodeficiency and antiretroviral treatment on the occurrence and evolution of abnormal Papanicolaou tests.

STUDY DESIGN

Cohort of 485 HIV-infected women with a known date of infection, enrolled during May 1993-April 1998 in 23 centres (gynaecology, infectious disease or STD clinics, or drug treatment centres) in 12 European countries; in 21 centres, follow-up was performed every 6 months (median follow-up: 2 years).

METHODS

Human papillomavirus (HPV) was detected at inclusion by Southern blot and PCR. The prevalence of squamous intraepithelial lesions (SIL), the incidence of SIL and regression from low-grade SIL were studied according to CD4 count after controlling for HPV detection results.

RESULTS

Compared with women with CD4 cell counts > 500 x 10(6)/l, women with CD4 cell counts < 200 x 10(6)/l had a twofold increase in both prevalence and incidence of SIL and in non-regression from untreated low-grade SIL; in addition, these women had a lower response rate to treatment of high-grade cervical intraepithelial neoplasia. The increase in SIL incidence associated with a low CD4 cell count was significant in women not receiving antiretroviral treatment (relative risk, CD4 cell count 200-499 x 10(6)/l, 1.9; CD4 cell count < 200 x 10(6)/l, 2.9; CD4 cell count > 500 x 10(6)/l, reference), whereas it was less marked and not statistically significant in treated women.

CONCLUSIONS

Severe HIV-related immunodeficiency strongly increases the risk of occurrence of SIL; antiretroviral treatment may reduce this risk, probably by restoring or at least preserving immune function.

Lessons from a multicentre study of the detectability of viral genomes based on a two-round quality control of GB virus C (GBV-C)/hepatitis G virus (HGV) polymerase chain reaction assay

The aim of this study was to determine whether multicentre quality controls for the detectability of viral genomes could contribute to the improvement of diagnostic performance in the participating laboratories. The study was carried out during two successive rounds, during which 18 laboratories specialized in nucleic acid testing analyzed, through a polymerase chain reaction (PCR) assay, a common panel of GB virus C (GBV-C)/hepatitis G virus (HGV) RNA-positive and -negative samples. During the first round, the laboratories used either an 'in-house' PCR procedure or a partly standardized commercial test. After decoding the results of the first round, the procedures of the participating laboratories were compared in order to establish a consensus procedure deduced from those of the laboratories which provided the best results. During the second round, each participating laboratory could use the resulting consensus procedure, or its own procedure, or both. The results of this quality control study indicated that, whatever method used, even specialized and trained laboratories may give false-negative or false-positive results. The commercial assay did not guarantee a systematic high quality level of results. The striking heterogeneity of results observed among laboratories using the same commercial assay confirm that molecular biology methods need skilled technicians. The results of this quality control study suggest that full standardization of viral genome detection, including all steps of the procedure, is necessary and that the laboratories performing PCR should participate in repeated quality control studies, whatever technique is being used.

[Detection of human papillomavirus in cutaneous extragenital Bowen's disease in immunocompetent patients]

INTRODUCTION

A specific link between human papillomavirus (HPV) types 16, 18, 31, and 33 and genital carcinomas and between HPV type 5 and cutaneous extragenital carcinomas in patients with epidermodysplasia verruciformis and renal transplant has been previously found. The aim of this prospective study was to detect HPV in cases of cutaneous extragenital Bowen's disease (BD) from non-immunosuppressed patients.

PATIENTS AND METHODS

Twelve cases of cutaneous extragenital BD or Bowen's carcinoma (BC), seen in the period 1994-1996 and confirmed by histologic examination, were included in the study. Tissue sections were studied by in situ hybridization with a mixture of HPV DNA probes and specific HPV DNA probes. In addition, study on fresh materiel from 1995 included: Southern blot hybridization with various usual HPV probes (6, 11, 16, 18, 31, 33, 35, 39, 42), polymerase chain reaction (PCR) with hybridization using consensus HPV probes and probes specific for HPV types 6, 11, 16, 18 and 33. In positive samples with conventional PCR, in situ PCR with probes specific for HPV types 6/11 and 16 was performed on tissue sections.

RESULTS

In situ hybridization was negative in all the cases. Southern blot hybridization was negative in our 9 studied cases. Three cases studied by consensus PCR were positive. PCR with specific HPV probes revealed positivity on two of these cases: HPV 6 in one, and HPV 16 in another. In situ PCR was positive with a mixed 6/11 HPV probe in the third positive consensus PCR case.

DISCUSSION

Our study revealed the presence of HPV in 3 out of 12 cases of cutaneous extragenital BD and BC. HPV type 16, found in BC of skull, was the most usually found type in the literature. HPV types 6/11, detected in 2 cases, were rarely found in cutaneous extragenital BD and BC and these results are in favor of the oncogenic effect of these virus types. In our study, in situ hybridization and Southern blot hybridization were negative in all the cases; HPV was only found in 3 cases by conventional PCR and in 1 case by in situ PCR. The low range of detection of HPV in cutaneous extragenital BD may be due to the used methods, to difficulties related to sampling and/or to a low number of copies of the HPV genoma.

Quantification of hepatitis C virus RNA in serum by branched DNA-based signal amplification assays

The objective of the study was to compare the clinical sensitivity and specificity of versions 1.0 and 2.0 of the branched DNA (bDNA)-based hepatitis C virus (HCV) RNA quantification assay, and also to compare the values yielded by the two versions according to the HCV genotype. Serum samples from 268 patients tested routinely by a non-quantitative HCV RNA PCR assay (group A) were tested with version 2.0 of the bDNA assay. Samples from 342 HCV PCR-positive patients with chronic hepatitis C eligible for interferon treatment (group B) were tested with both version 1.0 and version 2.0 of the bDNA assay. Version 2.0 had a clinical sensitivity of 92% (95% confidence interval (CI): 87-97%) in group A and 89% (86-92%) in group B. In group B, the gain in sensitivity with bDNA 2.0 was 16% relative to bDNA 1.0 (P < 0.001). The log values of the two assays correlated with samples positive by both assays (r = 0.83, P < 0.0001), but the distribution of values was larger in samples containing HCV genotypes 2 and 3. The mean ratio of assay 2.0/assay 1.0 values was 1.69 +/- 1.44 (range: 0.33-13.43). The mean ratio was close to 1 with samples containing genotype 1 or 4, but ranged from 0.33 to more than 5. The mean ratio was close to 3 with samples containing genotype 2 or 3, and ranged from 0.5 to more than 13. HCV RNA levels were significantly lower in samples containing genotype 4 than in those containing other genotypes. Sera from 200 anti-HCV-negative, HCV RNA PCR-negative blood donors (group C), and from 164 anti-HCV-negative patients with symptoms of chronic liver disease (group D) were used to assess the clinical specificity of bDNA 2.0. In addition, samples with an HCV RNA titer between 0.2 (assay cutoff) and 0.5 MEq/ml from a group of 546 patients tested routinely for HCV RNA load by bDNA 2.0 (group E) were retested by bDNA 2.0 and by qualitative PCR. The specificity of bDNA 2.0 was 100% (98-100%) in group C and 99% (97-100%) in group D. Among the 41 samples from group E, 38 were positive by bDNA 2.0 retesting (36 were PCR-positive) and three were negative by bDNA 2.0 retesting (all were PCR-positive). It is concluded that version 2.0 of the bDNA assay is markedly more sensitive than version 1.0 and has a good specificity. In contrast with version 1.0, version 2.0 is not influenced by the HCV genotype. The relationship between values obtained with assays 1.0 and 2.0 on clinical specimens is not linear, indicating that HCV RNA titers cannot reliably be calculated from the results of version 1.0.

First case of yellow fever in French Guiana since 1902

The first case of yellow fever in French Guiana since 1902 was reported in March 1998. The yellow fever virus genome was detected in postmortem liver biopsies by seminested polymerase chain reaction. Sequence analysis showed that this strain was most closely related to strains from Brazil and Ecuador.

Identification of Mycobacterium DNA in an Egyptian Pott's disease of 5,400 years old

The antiquity of tuberculosis in the Old World is controversial because the morphology of the lesion in skeletal remains is non-specific. We report the recovery of a DNA fragment from a 5,400-year-old Predynastic Egyptian skeleton that exhibits a kyphotic, 'hunchback' spinal deformity consistent with Pott's disease and suggestive of tuberculous vertebral involvement. The recovered DNA fragment was sequenced and is consistent with an original Mycobacterium sequence. We cannot prove that it is M. tuberculosis, M. bovis or an ancient mycobacteria resembling the two current forms because the observed modifications in the sequence could be attributed to the antiquity of Mycobacterium and/or to the effects of Taq polymerase. This provides the most specific evidence for the antiquity of human Mycobacterium disease in the world.

[Uveitis in Whipple disease: Identification of Trophyrema whippelii by PCR]

Whipple's disease is a multisystem bacterial disease usually characterized by malabsorption, diarrhea and polyarthritis. Ocular manifestations include uveitis, vitreitis, retinis, myositis, papilledema and optic atrophy. We report a case of a chronic bilateral vitreitis in a 63 year-old man who had been treated for a Whipple's disease with gastrointestinal involvement 30 years before. The jejunal biopsy was negative but the polymerase-chain-reaction (PCR) revealed the presence of Trophyrema Whippelii in the vitreous prelevement of both eye. This new, original strategy of PCR is specific and more sensitive than histological diagnosis.

Whipple's syndrome (uveitis, B27-negative spondylarthropathy, meningitis, and lymphadenopathy) associated with Arthrobacter sp. infection

OBJECTIVE

To report an unusual case of Whipple's disease, including uveitis, seronegative spondylarthropathy, meningitis, and lymphadenopathy, associated with an Arthrobacter sp. infection.

DESIGN

Interventional case report.

PATIENT AND INTERVENTION

A 60-year-old white man presenting with severe chronic uveitis and systemic inflammatory manifestations was treated efficiently for Whipple's disease after histopathologic analysis of vitreous and inguinal adenopathy biopsy specimens. The authors performed a retrospective, laboratory-based evaluation of stored tissue specimens.

MEASUREMENTS

Molecular analysis based on 16S ribosomal RNA gene amplification was applied to pretreatment biopsy specimens of inguinal lymph node to identify a causative bacterial agent.

RESULTS

Tropheryma whippelii genome was not detected in these specimens. However, an amplification product was obtained after the first polymerase chain reaction run and subsequently was sequenced. It corresponded to an Arthrobacter sp., a gram-positive agent presenting diagnostic patterns and therapeutic management similar to those of Whipple's disease caused by T. whippelii.

CONCLUSION

The absence of T. whippelii identification by molecular amplification during a clinically and histologically oriented Whipple's syndrome should not rule out the diagnosis. Arthrobacter infection may represent a new bacterial etiology of systemic inflammatory disorders involving the eye and associated with periodic acid-Schiff-positive inclusions.

Comparison of two serological methods and a polymerase chain reaction-enzyme immunoassay for the diagnosis of acute respiratory infections with Chlamydia pneumoniae in adults

Chlamydia pneumoniae is a common respiratory tract pathogen. Serological methods currently used for the diagnosis of C. pneumoniae infection lack specificity, give ambiguous results from a single serum sample and often provide only a retrospective diagnosis. A prospective study was undertaken to assess whether PCR could be a useful addition to the serological techniques routinely practised for diagnosis. This study investigated 68 adult patients with a diagnosis of acute respiratory infection. Acute and convalescent serological determination of antibodies to C. pneumoniae were performed by means of an rELISA test and a micro-immunofluorescence (MIF) test. Nasopharyngeal aspirates or bronchoalveolar lavage specimens and bronchial aspirates obtained from the 68 patients were evaluated by PCR-enzyme immunoassay (PCR-EIA) for the presence of C. pneumoniae and by immunofluorescence assay and cell culture for virus identification. Mycoplasma pneumoniae serology was also performed. Eight patients (11.8%) were positive by either rELISA or PCR-EIA, or both, with an infection rate of 5 (18.5%) of 27 in patients with community-acquired pneumonia, 2 (9%) of 22 in asthmatic patients and 1 (5%) of 19 in patients with an exacerbation of chronic obstructive pulmonary disease. Serological evidence of acute infection was found in four of these patients with the rELISA test and in three others with the MIF test. PCR-EIA detected C. pneumoniae DNA in four specimens, but there were concordant results with both rELISA and PCR-EIA in only one patient A positive PCR-EIA was also obtained in a patient who did not show an antibody response in acute serum. The discrepancy between serological and PCR-EIA results reflects the difficulties in routine laboratory diagnosis of C. pneumoniae infection and the necessity for further studies with optimised techniques.

Comparative prevalence, incidence and short-term prognosis of cervical squamous intraepithelial lesions amongst HIV-positive and HIV-negative women

OBJECTIVE

To investigate the impact of HIV infection on the prevalence, incidence and short-term prognosis of squamous intraepithelial lesions (SIL), in a prospective study with 1-year follow-up.

METHODS

Between 1993 and 1995, 271 HIV-positive and 171 HIV-negative women at high risk of HIV infection were recruited, 365 (82.6%) of whom completed the 1-year follow-up. The women underwent a Papanicolaou smear test at inclusion and at 6 and 12 months. Human papillomavirus (HPV) was detected at inclusion by Southern blot and PCR.

RESULTS

The SIL prevalence ranged from 7.5% for HIV-negative to 31.3% for HIV-positive women with CD4 cell counts < 500 x 10(6)/l (P < 0.001). Other factors associated independently and significantly with SIL prevalence were HPV-16, 18, 33 and related types, HPV-31, -35, -39 and related types, lifetime number of partners, younger age, past history of SIL and lack of past cervical screening. The SIL incidence ranged from 4.9% in HIV-negative women to 27% in HIV-positive women with CD4 cells < 500 x 10(6)/l (P < 0.001). Progression from low- to high-grade SIL during follow-up was detected in 38.1% of HIV-positive women with CD4 cells < or = 500 x 10(6)/l but in no HIV-negative nor HIV-positive women with CD4 cells > 500 x 10(6)/l. HPV-16, 18, 33 and related types were also associated with higher incidence of SIL and progression from low- to high-grade SIL.

CONCLUSION

HIV-induced immunodeficiency is associated with high prevalence, incidence and persistence/progression of SIL. A pejorative influence of HIV infection without marked immunodeficiency is less clear. HIV-positive women with SIL may thus benefit from early treatment when a useful immune response is still present.

Comparison of clinical, histological, and virological symptoms of HPV in HIV-1 infected men and immunocompetent subjects

OBJECTIVE

We assessed the clinical, histological, and virological features of anogenital human papillomavirus (HPV) infection, according to their immune status in HIV-1 infected men, referred for an anogenital examination or treatment, in comparison with immunocompetent patients.

METHODS

The study population comprised 33 HIV-1 infected heterosexual or homosexual men and 38 HIV negative men seen in a screening and treatment centre for anogenital HPV infections. All patients were examined with a colposcope. Biopsies were carried out on all subjects with anogenital lesions for histological studies and HPV detection by Southern blot.

RESULTS

The HIV infected patients had a balanopreputial HPV infection in 70%, anal in 30%, and urethral in 37%, while HIV negative patients had balanopreputial lesion in 72%, anal in 26%, and urethral in 16%. Diffuse anogenital lesions were present in 33% of the HIV infected cases and in 10.5% of HIV negative cases (p < 0.02). Among the HIV infected patients, the genital HPV lesions were condylomatous in 67.5% of the cases and dysplastic in 57%. HIV negative patients had condylomatous lesions in 86% of the cases and dysplasic in 14%. The condylomatous lesions of HIV infected patients had a low grade malignant histological aspect in 36% of the cases and high grade histological criteria were found in 22% of the dysplasias. Oncogenic HPVs were detected more frequently in HIV infected patients (35% v 12%) and more than one HPV type was found in 21.5% of cases. Neither the anogenital diffusion of the HPV lesions nor their morphological, histological, and virological features differed significantly in patient with CD4 cell counts > or < 200 x 10(6)/l. In contrast, patients with CD4 cell counts < 50 x 10(6)/l had a higher risk of several types of HPVs and of developing a diffuse anogenital infection.

CONCLUSION

HIV-1 infected patients had an increased frequency of high grade anogenital dysplastic lesions and a higher frequency of HPV infection with multiple and diffuse sites of involvement. These characteristics of HPV infection were independent of the patients' immune status up to CD4 cell counts > 50 x 10(6)/l but showed an increased risk when the CD4 cell count was < 50 x 10(6)/l. The higher frequency of diffuse anogenital infections among HIV infected men calls for rapid treatment, laser or surgery, given the association of histological features of intraepithelial neoplasia and the presence of multiple HPV infection sites which may be the consequence of immune disturbances, most of which are transmissible potentially oncogenic HPVs.

Human immunodeficiency virus infection and AIDS in a person with negative serology

A 38-year-old woman resident of Ivory Coast died of AIDS, while remaining human immunodeficiency virus (HIV)-seronegative. She had been regularly tested because her husband was HIV-seropositive. The subject's lack of specific antibodies was assessed using commercial tests and confirmed by a radioimmunoprecipitation assay of the patient's virus. She was unquestionably HIV-1-infected, with a high plasma virus load, and her virus could be isolated. Molecular analyses indicated this retrovirus was clade A, which is common in Africa, and it was highly homologous to the virus isolated from her husband. The subject's seronegative status was thought to be due to rapid depletion of specific CD4+ helper T cells, resulting from accelerated disease progression, and was host-related rather than due to a specific HIV strain.

[Prevalence of Chlamydia trachomatis among men consulting in urology. Comparative study between cell culture and sperm PCR]

OBJECTIVE

Genital Chlamydia trachomatis infection can be difficult to diagnose, depending on the precise site of infection. Given the lack of major clinical signs and symptoms in many cases and the risk of male and female infertility. Chlamydia trachomatis is a public health problem. It can be difficult to detect this pathogen in sperm by means of cell culture, because of seminal fluid toxicity for cell lines. New techniques such as the polymerase chain reaction (PCR) can be used to detect genomic DNA.

STUDY DESIGN

We studies 81 patients by applying the Amplicor CT PCR test to sperm, in comparison with cell culture on sperm and urethral samples.

RESULTS

The prevalence of Chlamydia trachomatis infection was not significantly different (3.7% vs 5%) in the urethral cell culture and PCR methods, respectively (p > 0.05). In contrast, PCR was significantly more sensitive than sperm cell culture (5% vs 1.2%; p < 0.03). Moreover, we have not detected of genital chlamydiose among the infertile men.

CONCLUSION

These findings suggest that PCR detection of Chlamydia trachomatis can dispense with the need for urethral sampling and cell culture in selected male patients.

Genitourinary tuberculosis: rapid diagnosis using the polymerase chain reaction

We present the case of a patient with suspected genitourinary tuberculosis in whom confirmation by direct smear examination was negative. Detection of mycobacterial DNA by use of the polymerase chain reaction (PCR) established the diagnosis, which was confirmed by culture 4 weeks later. Given its very high sensitivity and positivity, PCR may become the method of choice for rapid diagnosis of genitourinary tuberculosis and institution of therapy.

Unapparent systemic dissemination of Mycobacterium tuberculosis

A healthy 6-week-old girl exposed to tuberculosis presented a positive DNA amplification for Mycobacterium tuberculosis complex in gastric aspirates and cerebrospinal fluid whereas she had no other clinical or biological symptoms. Cultures were negative. This report underlines the interest of polymerase chain reaction for early diagnosis of tuberculosis and suggests the importance of treating exposed neonates and young infants just as active tuberculosis.

Use of polymerase chain reaction for improved diagnosis of tuberculosis in children

OBJECTIVE

To study the value of a rapid diagnostic method based on the amplification by polymerase chain reaction (PCR) of a fragment of the IS6110 insertion element for the detection of Mycobacterium tuberculosis in children.

DESIGN

We tested 199 specimens obtained from 68 children referred for evaluation of suspected tuberculosis.

RESULTS

In 83.3% of children with active disease and 38.9% with tuberculous infection but no evidence of disease, at least one positive PCR result was observed. No child without tuberculosis had positive PCR results (100% specificity). The sensitivity of the PCR was increased by testing of multiple samples from the same child and use of Chelex particles (Bio-Rad Laboratories, Ivry, France) rather than guanidine isothiocyanate-silica particles for DNA extraction. Bronchoalveolar lavage samples were no more useful than gastric aspirates.

CONCLUSIONS

If appropriate laboratory methods are used, DNA amplification is a reliable method for the early diagnosis of tuberculosis in children and appears to be very helpful in clinical pediatric practice when the diagnosis of active tuberculosis is difficult or needs to be rapidly confirmed.

[Generalized BCG infection after intravesical instillations of Calmette-Guerin bacillus]

BCG has been disappointing as immunotherapy of numerous cancers, but it has been clinically successful in the intravesical treatment of bladder carcinomas sparing the muscle coat; it has indeed become the reference treatment for this type of cancer. However, complications are repeatedly reported, including generalized BCGitis. We report such a case with positive BCG culture. From the cases already published there emerges a homogeneous and often subacute clinical presentation suggestive of an ordinary pathogen. Bacteriology is not very helpful, even when recent techniques are used, and therefore the diagnosis rests on the context and, when samples are taken, on suggestive histological findings. To discuss the physiopathology of BCGitis--generalized immune reaction or multifocal BCG proliferation--is not useless since treatment depends on it. It is probable that these 2 mechanisms working together can be incriminated justifying the prescription of both antibiotics and corticosteroids. When this is done, the prognosis seems to be favourable in most patients. Yet a strict respect of contra-indications and a very careful subsequent radiotherapy should reduce the risks.

Evaluation of nonradioactive DNA probes for identification of mycobacteria

Commercial chemiluminescent DNA probes (Accuprobe; Gen-Probe, San Diego, Calif.) for the identification of Mycobacterium tuberculosis (MTB) complex, M. avium complex (MAC), M. gordonae, and M. kansasii were evaluated with 134 clinical isolates. These included 36 MTB complex, 40 MAC, 27 M. gordonae, 9 M. kansasii, and 22 Mycobacterium spp. The specificity was 100% for the four probes. The sensitivity was 100% for the MTB complex and M. gordonae probes and 95.2% for the MAC probe. Five of the nine M. kansasii isolates tested were not detected with the probe.

Quantitative in situ hybridization using strand specific RNA probes: expression of the bunyavirus Germiston S segment in mosquito cells

Infection of Vero (monkey) cells by Germiston bunyavirus is highly cytopathic with cell lysis and virus production at a high titre, whereas infection of Aedes albopictus C6/36 (mosquito) cells leads, after an acute primary phase, to a persistent non-cytopathic infection with a loss in virus production. In this report we demonstrate that single-stranded RNA probes can be successfully used in an in situ hybridization assay to quantify viral expression during this persistent infection. The steady-state levels of viral S-RNA segment (genomic and messenger sense) during the acute phase were similar to those observed in lytically infected Vero cells, but appeared delayed. Both senses of S-RNA were detected throughout persistent infection but in lower amounts, in less than 10% of the cells and always in the cytoplasm of infected cells. The number of copies per cell of messenger sense S-RNAs remained low during persistent infection whereas a higher fluctuation was observed for genomic S-RNAs. In situ hybridization with specific stranded RNA probes provides both qualitative and quantitative informations, that can lead to a better understanding of virus-cell interactions.

Detection of the bunyavirus Germiston in VERO and Aedes albopictus C6/36 cells by in situ hybridization using cDNA and asymmetric RNA probes

Using Germiston virus infected vertebrate (VERO) and invertebrate (Aedes albopictus C6/36) cells, paraformaldehyde-glutaraldehyde fixative allowed the best preservation of cellular morphology and the highest hybridization signals with cDNA and asymmetric RNA probes against the viral S segment. Asymmetric RNA probes always gave higher sensitivity and better specificity of in situ hybridization than the nick-translated symmetric DNA probe in both vertebrate and invertebrate cells. The study of Aedes albopictus C6/36 cells persistently infected with Germiston virus showed that only a small number of cells contained the S segment, and that the replication and transcription of the S segment took place in the cytoplasm of acutely and persistently infected cells.