Need for caution when interpreting Xpert® MTB/RIF results for rifampin resistance among children.

BACKGROUND: Recommended by the World Health Organization as an initial diagnostic test for TB in children, Xpert® MTB/RIF is widely implemented in many countries, including Kenya.METHODS: Three hundred HIV-positive and negative children (<5 years) were enrolled in Kisumu County, Kenya, from October 2013 to August 2015. Multiple specimen types were collected from each child and tested using Xpert, liquid culture, and phenotypic drug susceptibility testing (DST). Samples positive for rifampin (RIF) resistance on Xpert were tested using line-probe assay and sequencing.RESULTS: Of 32 children with bacteriologically confirmed TB, 27 had positive Xpert results. Of these, 3/27 (11%, 95% CI 4-28) had RIF resistance detected on Xpert, but not by phenotypic DST, line-probe assay, or sequencing. For these three children, five Xpert tests showed RIF resistance; all five tests had semi-quantitative "very low" results and delay or absence of probe D signal, whereas no Xpert results with higher semi-quantitative results showed RIF resistance. All three children responded well to standard TB treatment.CONCLUSIONS: False RIF resistance may be detected in pediatric specimens. Further study is needed to determine if false RIF resistance is associated with low bacterial load.

Comparison of Mycobacterium tuberculosis complex Yield and Contamination Rates using Lowenstein-Jensen with and without Antibiotics in Western Kenya.

Background: While molecular methods have been recently endorsed for diagnosis of tuberculosis (TB), mycobacterial culture remains the gold standard. Lowenstein-Jensen (LJ) is often used for the cultivation of Mycobacterium tuberculosis complex (MTBC); however contamination often renders a subset of cultures useless. We compared the MTBC yield and contamination rate of processed sputum inoculated on LJ with antibiotics (LJ PACT) to LJ without antibiotics (LJ). Methodology: Sputum samples were obtained from people living with HIV enrolled in a TB screening study in western Kenya, processed using NALC/NaOH-Na citrate, then inoculated on LJ PACT and LJ media. Cultures were evaluated weekly with growth identified as acid-fast bacilli by Ziehl-Neelsen bright-field microscopy. MTBC and nontuberculous mycobacteria (NTM) were identified by immunochromatographic and line probe assays. Results: A total of 700 sputum samples were cultured on both LJ PACT and LJ between March and June 2012. Of those cultured on LJ PACT, 29 (4.1%) grew MTBC, 613 (87.6%) were negative, 12 (1.7%) grew NTM, and 46 (6.6%) were contaminated; on LJ, 28 (4%) grew MTBC, 553 (79%) were negative, 9 (1.3%) grew NTM, and 110 (15.7%) were contaminated. The difference in contamination on LJ PACT and LJ was statistically significant (p<0.0001), while the difference in MTBC growth was not (p=0.566).

Assessing the effect of decentralisation of laboratory diagnosis for drug-resistant tuberculosis in Kenya.

SETTING: Drug susceptibility testing (DST) is recommended in Kenya to identify multidrug-resistant tuberculosis (MDR-TB) in persons registered for tuberculosis (TB) retreatment. DST is performed at a central laboratory with a two-step growth-based process and a regional laboratory with a simultaneous molecular- and growth-based process. OBJECTIVE: To compare proportions of retreatment cases who underwent DST and turnaround times for hospitals referring to the central vs. regional laboratory. DESIGN: Cases were persons registered for TB retreatment from 1 January 2012 to 31 December 2013. Records of 11 hospitals and 7 hospitals referring patients to the regional and central laboratories, respectively, were reviewed. RESULTS: Respectively 238/432 (55%) and 88/355 (25%) cases from hospitals referring to the regional and central laboratories underwent DST. The mean time from case registration to receipt of DST results and initiation of MDR-TB treatment was quicker in hospitals referring to the regional laboratory. The time required for the transportation of specimens, specimen testing and receipt of DST results at hospitals was shorter for the regional laboratory (P < 0.05). CONCLUSION: Testing was faster and more complete at hospitals referring to the regional laboratory. A comprehensive review of MDR-TB detection in Kenya is required to increase the proportion of cases receiving DST.

Experience in implementing a quality management system in a tuberculosis laboratory, Kisumu, Kenya.

We implemented a quality management system (QMS) and documented our improvements in a tuberculosis (TB) laboratory in Kisumu, Kenya. After implementation of the QMS, a sustained reduction in culture contamination rates for solid (from 15.4% to 5.3%) and liquid media (from 15.2% to 9.3%) was observed, and waste from product expiry was reduced significantly. External quality assurance (EQA) results were satisfactory before and after QMS implementation, and a client survey after implementation revealed 98% satisfaction. The laboratory attained ISO 15189 accreditation in October 2013. The implementation of QMS facilitated the attainment of target quality indicators, reduced waste due to expiry and led to high client satisfaction.

Pregnancy and HIV transmission among HIV-discordant couples in a clinical trial in Kisumu, Kenya.

OBJECTIVES: A large proportion of new HIV infections in sub-Saharan Africa occur in stable HIV-discordant partnerships. In some couples, the strong desire to conceive a child may lead to risky behaviour despite knowledge of discordant serostatus. Our objective was to compare HIV transmission between discordant couples who did and did not conceive during participation in a clinical trial. METHODS: Five hundred and thirty-two HIV-discordant couples were followed for up to 2 years in Kisumu, Kenya as part of the Partners in Prevention HSV/HIV Transmission Study. Quarterly HIV-1 antibody and urine pregnancy test results were analysed. RESULTS: Forty-one HIV-1 seroconversions occurred over 888 person-years of follow-up, resulting in an annual incidence of 4.6/100 person-years. Twenty seroconversions occurred among 186 HIV-1-uninfected individuals in partnerships in which pregnancy occurred (10.8% of HIV-1-negative partners in this group seroconverted), in comparison to 21 seroconversions among 353 uninfected individuals in partnerships in which pregnancy did not occur (5.9% of HIV-1-negative partners seroconverted), resulting in a relative risk of 1.8 [95% confidence interval (CI) 1.01-3.26; P<0.05]. CONCLUSIONS: Pregnancy was associated with an increased risk of HIV seroconversion in discordant couples. These data suggest that the intention to conceive among HIV discordant couples may be contributing to the epidemic.