Molecular surveillance of drug resistance: Plasmodium falciparum artemisinin resistance single nucleotide polymorphisms in Kelch protein propeller (K13) domain from Southern Pakistan.

BACKGROUND: K13 propeller (k13) polymorphism are useful molecular markers for tracking the emergence and spread of artemisinin resistance in Plasmodium falciparum. Polymorphisms are reported from Cambodia with rapid invasion of the population and almost near fixation in south East Asia. The study describes single nucleotide polymorphisms in Kelch protein propeller domain of P. falciparum associated with artemisinin resistance from Southern Pakistan. METHODS: Two hundred and forty-nine samples were collected from patients with microscopy confirmed P. falciparum malaria attending Aga Khan University Hospital during September 2015-April 2018. DNA was isolated using the whole blood protocol for the QIAmp DNA Blood Kit. The k13 propeller gene (k13) was amplified using nested PCR. Double-strand sequencing of PCR products was performed using Sanger sequencing methodology. Sequences were analysed with MEGA 6 and Bio edit software to identify specific SNP combinations. RESULTS: All isolates analysed for k13 propeller allele were observed as wild-type in samples collected post implementation of ACT in Pakistan. C580Y, A675V, Y493H and R539T variants associated with reduced susceptibility to artemisinin-based combination therapy (ACT) were not found. Low frequency of M476I and C469Y polymorphisms was found, which is significantly associated with artemisinin resistance. CONCLUSION: Low frequencies of both nonsynonymous and synonymous polymorphisms were observed in P. falciparum isolates circulating in Southern Pakistan. The absence of known molecular markers of artemisinin resistance in this region is favourable for anti-malarial efficacy of ACT. Surveillance of anti-malarial drug resistance to detect its emergence and spread need to be strengthened in Pakistan.

Cytomegalovirus Colitis in a Patient With Ulcerative Colitis on Vedolizumab Monotherapy.

Cytomegalovirus (CMV) is a human herpes-type virus with variable clinical manifestations. Infections in immunocompetent patients are usually asymptomatic or mild, and severe infections are generally seen in immunosuppressed individuals. CMV colitis is not uncommon in patients with ulcerative colitis (UC) and is mostly associated with the use of steroids, immunomodulators like azathioprine, and biologics like infliximab, which have systemic immunosuppressive effects. Vedolizumab is an anti-integrin antibody that is gut-selective without any systemic effects. We report an unusual presentation of a female patient with UC who had concomitant CMV colitis and erythema nodosum, who was on vedolizumab, and not on any steroids or other immunosuppressants. She responded well to anti-viral treatment and steroids.