Toxin A-negative toxin B-positive ribotype 017 Clostridium difficile is the dominant strain type in patients with diarrhoea attending tuberculosis hospitals in Cape Town, South Africa

Abstract

The molecular epidemiology of C. difficile strains causing disease in South Africa is currently unknown. Previously, multidrug resistant ribotype (RT)017 strains were those most commonly isolated from patients with diarrhoea attending Groote Schuur Hospital in Cape Town, South Africa. This larger study aimed to investigate the molecular epidemiology and antibiotic susceptibility profiles of C. difficile strains in the greater Cape Town and regional areas. C. difficile strains were isolated from patients with diarrhoea attending hospitals in the Western Cape region of South Africa that tested positive using the GeneXpert CDiff diagnostic test. Ribotyping and multilocus variable-number tandem-repeat analysis (MLVA) were used to type isolates, and their susceptibilities to several antibiotics were determined by gradient diffusion test strips. A total of 269 non-repeat C. difficile isolates were obtained. A large proportion of isolates (64.3 %) belonged to the RT017 group, many of which were clonally related when investigated by MLVA. RT017 strains were particularly prevalent in patients attending specialist tuberculosis (TB) hospitals. The majority of RT017 isolates were co-resistant to moxifloxacin and rifampicin, two antibiotics which are used intensively during anti-TB therapy. Non-RT017 strains were generally susceptible to both antibiotics. Resistance to erythromycin was observed for both groups of strains. RT017 C. difficile strains are the most commonly isolated strains from patients attending healthcare facilities in the greater Cape Town and regional areas. The presence of multidrug resistant RT017 strains in patients with diarrhoea attending local TB hospitals reflects a potential reservoir for future infections.

Clostridioides difficile infection in the Asia-Pacific region

“…Less is known of the molecular epidemiology of C. difficile in South America, but RTs 027, 106, 012, 046, and 014/020 are reportedly the most common strains [31,33,34]. Similar to the current study, RT 017 (followed by RT 001) has also been found at high prevalence in South Africa [35], and in Ghana, Malawi, and Tanzania the few studies which performed molecular typing have shown a high prevalence of non-toxigenic strains [36,37], similar to reports from Southeast Asian countries [15].…”

Clostridium difficile in patients attending tuberculosis hospitals in Cape Town, South Africa, 2014–2015

“…This included samples from both DS tuberculosis and MDR tuberculosis patients and contrasts with a concurrent set of isolates obtained from patients attending other hospitals in the Cape Town area (37% of strains resistant to rifampicin). 30 It is also higher than that observed for strains isolated from the general hospital population in Europe (0% – 63.64%). 42 Rifampicin is included as part of the standard DS tuberculosis treatment regimen and exposure to antibiotics belonging to this class has been associated with the development of resistance in C. difficile .…”

“…5,53 RT017 strains were also commonly isolated from other hospitals in Cape Town during the same time period, suggesting that these strains are circulating more broadly in the Cape Town patient population. 30,54 It is possible that the previous use of standalone enzyme immunoassay diagnostic tests that target toxin A alone allowed RT017 strains to proliferate undetected in the region, providing a reservoir of strains in the healthcare environment with the potential to cause outbreaks in susceptible patient populations.…”

“…Adult patients with tuberculosis attending two specialist tuberculosis hospitals (designated Hospital A and Hospital B) in Cape Town between September 2014 and September 2015 were included as part of a larger surveillance study for CDI that has been published more fully elsewhere. 30 Both hospitals house patients undergoing tuberculosis therapy with adult wards divided into long-stay multi-drug resistant (MDR) and extensively drug resistant (XDR) wards and short-stay separate male and female wards for drug sensitive patients. Inclusion criteria were clinical suspicion of CDI (based on a C. difficile diagnostic test request from the attending clinician) and an unformed stool sample, collected in sterile specimen containers.…”

“…32,33 Isolates were typed by capillary gel electrophoresis-based ribotyping 34 and matched against a local strain database, which included a selection of profiles from the Cardiff Anaerobe Reference Unit (named according to the standard nomenclature) and the Swedish Institute for Communicable Disease Control (names preceded by ‘SE’ in the designation). 30 Further characterisation by multilocus variable-number tandem-repeat analysis (MLVA) was carried out as previously described. 35 Briefly, the calculated numbers of repeats at each locus were used to calculate a dissimilarity matrix based on the Manhattan distance between isolates.…”