The unusual neurologic manifestations posed a diagnostic challenge that was resolved through rapid typhoid antibody testing in the field and subsequent blood culture confirmation in the Malawi national reference laboratory. Extending laboratory diagnostic capacity, including blood culture, to populations at risk for typhoid fever in Africa will improve outbreak detection, response, and clinical treatment.

Although numerous studies have investigated diarrhoea aetiology in many sub-Saharan African countries, recent data on Shigella species’ involvement in community-acquired acute diarrhoea (CA-AD) in Malawi are scarce. This study investigated the incidence, antibiotic susceptibility profile, genotypic characteristics, and clonal relationships of Shigella flexneri among 243 patients presenting with acute diarrhoea at a District Hospital in Lilongwe, Malawi. Shigella spp. were isolated and identified using standard microbiological and serological methods and confirmed by identifying the ipaH gene using real-time polymerase chain reaction. The isolates’ antibiotic susceptibility to 20 antibiotics was determined using the VITEK 2 system according to EUCAST guidelines. Genes conferring resistance to sulfamethoxazole (sul1, sul2 and sul3), trimethoprim (dfrA1, dfrA12 and dfrA17) and ampicillin (oxa-1 and oxa-2), and virulence genes (ipaBCD, sat, ial, virA, sen, set1A and set1B) were detected by real-time PCR. Clonal relatedness was assessed using ERIC-PCR. Thirty-four Shigella flexneri isolates were isolated (an overall incidence of 14.0%). All the isolates were fully resistant to sulfamethoxazole/trimethoprim (100%) and ampicillin (100%) but susceptible to the other antibiotics tested. The sul1 (79%), sul2 (79%), sul3 (47%), dfrA12 (71%) and dfrA17 (56%) sulfonamide and trimethoprim resistance genes were identified; Oxa-1, oxa-2 and dfrA1 were not detected. The virulence genes ipaBCD (85%), sat (85%), ial (82%), virA (76%), sen (71%), stx (71%), set1A (26%) and set1B (18%) were detected. ERIC-PCR profiling revealed that the Shigella isolates were genetically distinct and clonally unrelated, indicating the potential involvement of genetically distinct S. flexneri in CA-AD in Malawi. The high percentage resistance to ampicillin and sulfamethoxazole/trimethoprim and the presence of several virulence determinants in these isolates emphasises a need for continuous molecular surveillance studies to inform preventive measures and management of Shigella-associated diarrhoeal infections in Malawi.

BackgroundStenotrophomonas maltophilia is a significant opportunistic pathogen that is associated with high mortality in immunocompromised individuals. In this study, we describe a multidrug-resistant (MDR) S. maltophilia clinical isolate from Kamuzu Central Hospital (KCH), Lilongwe, Malawi.MethodsA ceftriaxone and meropenem nonsusceptible isolate (Sm-MW08), recovered in December 2017 at KCH, was referred to the National Microbiology Reference Laboratory for identification. In April 2018, we identified the isolate using MALDI Biotyper mass spectrometry and determined its antimicrobial susceptibility profile using microdilution methods. Sm-MW08 was analysed by S1- PFGE, PCR, and Sanger sequencing, in order to ascertain the genotypes that were responsible for the isolate`s multidrug-resistance (MDR) phenotype.ResultsSm-MW08 was identified as S. maltophilia and exhibited resistance to a range of antibiotics, including all β-lactams, aminoglycosides (except arbekacin), chloramphenicol, minocycline, fosfomycin and fluoroquinolones, but remained susceptible to colistin and trimethoprim-sulfamethoxazole. The isolate did not harbour any plasmid but did carry chromosomally-encoded blaL1 metallo-βlactamase and blaL2 β-lactamase genes; this was consistent with the isolate’s resistance profile. No other resistance determinants were detected, suggesting that the MDR phenotype exhibited by Sm-MW08 was innate.ConclusionHerein, we have described an MDR S. maltophilia from KCH in Malawi, that was resistant to almost all locally available antibiotics. We therefore recommend the practice of effective infection prevention measures to curtail spread of this organism.