Fusion of inclusions following superinfection of HeLa cells by two serovars of Chlamydia trachomatis.

We used a double-label immunofluorescence assay to examine the ability of Chiamydia trachomatis serovar F to infect and develop within HeLa 229 cells previously infected with serovar E. No exclusion to superinfection occurred for up to 24 h following infection by serovar E. The percentage of HeLa cells infected in cultures inoculated with both strains was identical to that of cells in cultures inoculated with one strain as a control. Organisms of both serovars were located within the same intracellular inclusion in 88 to 95% of HeLa cells infected with both serovars. The proportion of superinfected HeLa cells containing both strains in separate inclusions increased when there was exposure to inhibitors of cytoskeletal structure and transport. We used this inhibition to demonstrate that fusion of C. trachomatis phagosomes occurs throughout the developmental cycle

Roles of laboratories and laboratory systems in effective tuberculosis programmes

Laboratories and laboratory networks are a fundamental component of tuberculosis (TB) control, providing testing for diagnosis, surveillance and treatment monitoring at every level of the health-care system. New initiatives and resources to strengthen laboratory capacity and implement rapid and new diagnostic tests for TB will require recognition that laboratories are systems that require quality standards, appropriate human resources, and attention to safety in addition to supplies and equipment. To prepare the laboratory networks for new diagnostics and expanded capacity, we need to focus efforts on strengthening quality management systems (QMS) through additional resources for external quality assessment programmes for microscopy, culture, drug susceptibility testing (DST) and molecular diagnostics. QMS should also promote development of accreditation programmes to ensure adherence to standards to improve both the quality and credibility of the laboratory system within TB programmes. Corresponding attention must be given to addressing human resources at every level of the laboratory, with special consideration being given to new programmes for laboratory management and leadership skills. Strengthening laboratory networks will also involve setting up partnerships between TB programmes and those seeking to control other diseases in order to pool resources and to promote advocacy for quality standards, to develop strategies to integrate laboratories’ functions and to extend control programme activities to the private sector. Improving the laboratory system will assure that increased resources, in the form of supplies, equipment and facilities, will be invested in networks that are capable of providing effective testing to meet the goals of the Global Plan to Stop TB

Laboratory Reporting of Tuberculosis Test Results and Patient Treatment Initiation in California

Prompt laboratory reporting of tuberculosis (TB) test results is necessary for TB control. To understand the extent of and factors contributing to laboratory reporting delays and the impact of reporting delays on initiation of treatment of TB patients, we analyzed data from 300 consecutive culture-positive TB cases reported in four California counties in 1998. Laboratory reporting to the specimen submitter was delayed for 26.9% of smear-positive patients and 46.8% of smear-negative patients. Delays were associated with the type of laboratory that performed the testing and with delayed transport of specimens. Referral laboratories (public health and commercial) had longer median reporting time frames than hospital and health maintenance organization laboratories. Among patients whose treatment was not started until specimens were collected, those with delayed laboratory reporting were more likely to have delayed treatment than patients with no laboratory reporting delays (odds ratio [OR] of 3.9 and 95% confidence interval [CI] of 1.6 to 9.7 for smear-positive patients and OR of 13.1 and CI of 5.3 to 32.2 for smear-negative patients). This relation remained after adjustment in a multivariate model for other factors associated with treatment delays (adjusted OR of 25.64 and CI of 7.81 to 83.33 for smear-negative patients). These findings emphasize the need to reduce times of specimen transfer between institutions and to ensure rapid communication among laboratories, health care providers, and health departments serving TB patients

Identification of a Mycobacterium tuberculosis Strain with Stable, Low-Level Resistance to Isoniazid

We have identified a potential quality control strain of Mycobacterium tuberculosis to monitor isoniazid susceptibility testing. This strain (strain A) has a stable phenotypic low-level resistance to isoniazid, has a mutation of C (−15) → T in the inhA promoter region, and gave consistent susceptibility test results in 141 laboratories

Assessment of Laboratory Performance of Nucleic Acid Amplification Tests for Detection of Mycobacterium tuberculosis

During implementation of the Centers for Disease Control and Prevention's Mycobacterium tuberculosis nucleic acid amplification (NAA) evaluation program, 27.1% of participants used the same biological safety cabinet for NAA and specimen processing; 28.8% reported not using unidirectional workflow. An association between false positives and adverse responses to quality assurance questions (P = 0.04) illustrated the need for following NCCLS recommendations

Global laboratory initiative tool for a stepwise process towards tuberculosis laboratory accreditation

Letter to the Editor about the Global Laboratory Initiative (GLI) tool