Geospatial distribution of severe paediatric intussusception in KwaZulu-Natal province, South Africa.

INTRODUCTION: intussusception in South African (SA) children is often severe. A proportion of cases require management at quaternary hospitals which are a scare resource in SA. A geospatial investigation of severe paediatric intussusception (SPI) in the KwaZulu-Natal (KZN) province of SA would assist with identifying regions which should be targeted for preventative interventions. This could reduce resource utilisation for this condition at quaternary hospitals. The objective of this study was to determine the geospatial distribution of SPI in KZN. METHODS: this was a retrospective analysis of data for patients with SPI who were admitted to a quaternary hospital in KZN over an 11-year period. Data related to patient demographics, duration of hospitalization, surgical intervention, inpatient mortality and residential postal code were extracted from the electronic hospital admissions system. Each residential postal code was linked to a corresponding KZN district municipality. Descriptive statistical methods were used to determine the distribution of various characteristics in the study sample. Semi-quantitative geospatial analysis was used to determine the distribution of patients with SPI in each KZN district municipality. RESULTS: the study sample consisted of 182 patients with SPI. Most patients were <1 year old (83.5%), male (51.1%) and black African (87.9%). All patients underwent surgical intervention. Inpatient mortality was 2.7%. The majority of patients in the study sample resided in the eThekwini and King Cetshwayo district municipalities (51.1% and 14.8%, respectively). CONCLUSION: preventative interventions for SPI should be considered for rollout in the eThekwini and King Cetshwayo district municipalities of KZN, SA.

Laboratory-acquired infections of Salmonella enterica serotype Typhi in South Africa: phenotypic and genotypic analysis of isolates.

BACKGROUND: Workers in clinical microbiology laboratories are exposed to a variety of pathogenic microorganisms. Salmonella species is among the most commonly reported bacterial causes of laboratory-acquired infections. We report on three cases of laboratory-acquired Salmonella enterica serotype Typhi (Salmonella Typhi) infection which occurred over the period 2012 to 2016 in South Africa. METHODS: Laboratory investigation included phenotypic and genotypic characterization of isolates. Phenotypic analysis included standard microbiological identification techniques, serotyping and antimicrobial susceptibility testing. Genotypic analysis included the molecular subtyping methodologies of pulsed-field gel electrophoresis analysis, multilocus sequence typing and whole-genome sequencing (WGS); with WGS data analysis including phylogenetic analysis based upon comparison of single nucleotide polymorphism profiles of isolates. RESULTS: All cases of laboratory-acquired infection were most likely the result of lapses in good laboratory practice and laboratory safety. The following critical issues were highlighted. There was misdiagnosis and misreporting of Salmonella Typhi as nontyphoidal Salmonella by a diagnostic laboratory, with associated public health implications. We highlight issues concerning the importance of accurate fluoroquinolone susceptibility testing and interpretation of results according to updated guidelines. We describe potential shortcomings of a single disk susceptibility screening test for fluoroquinolone susceptibility and suggest that confirmatory minimum inhibitory concentration testing should always be performed in cases of invasive Salmonella infections. These antimicrobial susceptibility testing issues resulted in inappropriate ciprofloxacin therapy which may have been responsible for failure in clearance of pathogen from patients. Salmonella Typhi capsular polysaccharide vaccine was not protective in one case, possibly secondarily to a faulty vaccine. CONCLUSIONS: Molecular subtyping of isolates proved effective to investigate the genetic relatedness of isolates. Molecular subtyping data interpreted together with epidemiological data allowed us to pinpoint the most likely sources for our cases of laboratory-acquired infection.

Culture-negative endocarditis due to Bartonella quintana.

Bartonella spp. was first described as a possible cause of culture-negative endocarditis in 1993, and has since emerged as a significant cause of this condition worldwide. We describe a complicated case of culture-negative endocarditis in an immune-competent male patient, which was confirmed on resected heart valves to have been caused by Bartonella quintana by broad-range 16S ribosomal RNA polymerase chain reaction. The objective of this report is to highlight the clinical, diagnostic and therapeutic challenges of Bartonella endocarditis.

Diagnostic accuracy of a rapid urine lipoarabinomannan test for tuberculosis in HIV-infected adults.

OBJECTIVE: In settings of high HIV prevalence, tuberculosis control and patient management are hindered by lack of accurate, rapid tuberculosis diagnostic tests that can be performed at point-of-care. The Determine TB LAM Ag (TB LAM) test is a lateral flow immunochromatographic test for detection of mycobacterial lipoarabinomannan (LAM) in urine. Our objective was to determine sensitivity and specificity of the TB LAM test for tuberculosis diagnosis. DESIGN: Prospective diagnostic accuracy study. SETTING: Hospital and outpatient settings in Uganda and South Africa. PARTICIPANTS: HIV-infected adults with tuberculosis symptoms and/or signs. METHODS: Participants provided a fresh urine specimen for TB LAM testing, blood for mycobacterial culture, and 2 respiratory specimens for smear microscopy and mycobacterial culture. MAIN OUTCOME MEASURES: For the TB LAM test, sensitivity in participants with culture-positive tuberculosis and specificity in participants without tuberculosis. RESULTS: A total of 1013 participants were enrolled. Among culture-positive tuberculosis patients, the TB LAM test identified 136/367 (37.1%) overall and 116/196 (59.2%) in the group with CD4 ≤100 cells per cubic millimeter. The test was specific in 559/573 (97.6%) patients without tuberculosis. Sensitivity of the urine TB LAM test plus sputum smear microscopy was 197/367 (53.7%) overall and 133/196 (67.9%) among those with CD4 ≤100. CD4 ≤50 [adjusted odds ratio (AOR), 6.2; P < 0.001] or 51-100 (AOR, 7.1; P < 0.001), mycobacteremia (AOR, 6.1; P < 0.01) and hospitalization (AOR, 2.6; P = 0.03) were independently associated with a positive TB LAM test. CONCLUSIONS: In HIV-positive adults with CD4 ≤100, the TB LAM urine test detected over half of culture-positive tuberculosis patients, in <30 minutes and without the need for equipment or reagents.