Membangun Model Matematika Penyebaran Penyakit Difteri Oleh Corynebacterium Diphtheriae Pada Populasi Manusia

Penyakit difteri pada manusia disebabkan oleh Corynecbacterium diphtheriae. Difteri menular melalui kontak langsung dan tidak langsung, menyerang semua kelompok usia, dan menyebabkan komplikasi bahkan kematian pada manusia. Penelitian ini bertujuan untuk membangun model matematika penyebaran penyakit difteri pada populasi manusia dengan menggunakan model SEIR (Susceptible-Exposed-Infected-Recovered) berdasarkan kondisi Corynebacterium diphtheriae. Model tersebut melibatkan subpopulasi manusia yang rentan terhadap penyakit (𝑆), subpopulasi manusia pada masa inkubasi (𝐸), subpopulasi manusia yang terinfeksi (𝐼), subpopulasi manusia yang telah sembuh dari penyakit (𝑅), subpopulasi manusia yang dikarantina (𝑈), subpopulasi bakteri sehat (𝐻), populasi virus yang menginfeksi bakteri (𝑉), dan subpopulasi bakteri mampu menghasilkan toksin (𝑀). Model matematika ini dianalisis kestabilannya dengan menggunakan metode linearisasi dan kriteria Routh-Hurwitz. Hasil penelitian menunjukkan bahwa titik kritis menggambarkan kondisi endemik yang stabil tanpa syarat. Hal inimenunjukkan bahwa penyakit difteri akan tetap ada dalam populasi manusia.

Cutaneous infection by non-diphtheria-toxin producing and penicillin-resistant Corynebacterium diphtheriae strain in a patient with diabetes mellitus

Diphtheria is a potentially fatal infection, mostly caused by diphtheria toxin (DT)-producing Corynebacterium diphtheriae strains. During the last decades, the isolation of DT-producing C. diphtheriae strains has been decreasing worldwide. However, non-DT-producing C. diphtheriae strains emerged as causative agents of cutaneous and invasive infections. Although endemic in countries with warm climates, cutaneous diphtheria is rarely reported in Brazil. Presently, an unusual case of skin lesion in a Brazilian elderly diabetic patient infected by a penicillin-resistant non-DT-producing C. diphtheriae strain was reported. Laboratory diagnosis included mass spectrometry and multiplex PCR analyses. Since cutaneous diphtheria lesions are possible sources of secondary diphtheria cases and systemic diseases and considering that penicillin is the first line of antimicrobial agent for the treatment of these infections, the detection of penicillin-resistant strains of diphtheria bacilli should be a matter of concern. Thus, cases similar to the presently reported should be appropriately investigated and treated, particularly in patients with risk factor (s) for the development of C. diphtheriae invasive infections, such as diabetes. Moreover, health professionals must be aware of the presence of C. diphtheriae in cutaneous lesions of lower limbs, a common type of morbidity in diabetic patients, especially in tropical and subtropical countries.

Newborn calf serum supplemented by tellurite as alternative transport medium for Corynebacterium diphtheriae

Indonesia is one of the five countries with highest diphtheria cases in the world. Laboratory confirmation by culture method as a gold standard requires bacterial survival. Indonesia’s geographical condition as an archipelagic country and difficulties in transporting clinical samples are often obstacles in maintaining bacterial survival. This study aims to evaluate the ability of several transport mediums to maintain the survival of Corynebacterium diphtheriae. A total of 90 isolates were divided into nine groups of transport mediums. Samples were divided into 2 treatment groups, namely room temperature and temperature 2-8 ºC. On day 2, 4, 8, 16, and 32, 1 isolate from each group with 2 different incubation temperatures was cultured on blood agar medium and incubated for 24 hours at 37 ºC. Bacterial survival was indicated by the growth of suspect colonies which were identified by microscopic and biochemical tests. Results show serum with tellurite can be used with viability lower than silica gel, but higher than other media. Meanwhile at a temperature of 2-8 ºC, there are 2 types of the best transport medium, namely serum with tellurite and open silica gel in aluminum foil. Newborn Calf Serum supplemented with Tellurite can be used as an alternative transport medium for Corynebacterium diphtheriae, both at room temperature and at 2-8 ºC.

Whole genome sequence of a non-toxigenic Corynebacterium diphtheriae strain from a hospital in southeastern China

Background Sporadic cases of infection with non-toxigenic Corynebacterium diphtheriae (C. diphtheriae) isolates have been reported in regions covered by the Diphtheria-Tetanus-Pertussis vaccine, but no information describing the whole genome of non-toxigenic strains collected in China is available. Therefore, in this work, the complete genome of a non-toxigenic strain of C. diphtheriae from a hospital located in southeastern China was performed. Results This non-toxigenic isolate belonged to the belfanti biotype and possessed a unique ST (assigned as ST799 in pubMLST). ErmX was present in the genome sequence and this isolate owned the resistance to erythromycin and clindamycin. Genes coding for virulence factors involved in adherence, iron-uptake and regulation of diphtheria toxin were also found. Two genes were involved in the interaction between pathogen and host. The phylogenetic analysis revealed that this newly isolated strain was similar to the strain NCTC10838, CMCNS703 and CHUV2995. Conclusion Non-toxigenic C. diphtheriae strain contained virulence factors, thus it is able to cause an infectious disease, aspect that could be clarified by performing the whole genome sequencing analysis.

Genomic epidemiology and strain taxonomy of Corynebacterium diphtheriae

Background Corynebacterium diphtheriae is highly transmissible and can cause large diphtheria outbreaks where vaccination coverage is insufficient. Sporadic cases or small clusters are observed in high-vaccination settings. The phylogeography and short timescale evolution of C. diphtheriae are not well understood, in part due to a lack of harmonized analytical approaches of genomic surveillance and strain tracking. Methods We combined 1,305 genes with highly reproducible allele calls into a core genome multilocus sequence typing (cgMLST) scheme. We analyzed cgMLST genes diversity among 602 isolates from sporadic clinical cases, small clusters or large outbreaks. We defined sublineages based on the phylogenetic structure within C. diphtheriae and strains based on the highest number of cgMLST mismatches within documented outbreaks. We performed time-scaled phylogenetic analyses of major sublineages. Results The cgMLST scheme showed high allele call rate in C. diphtheriae and the closely related species C. belfantii and C. rouxii . We demonstrate its utility to delineate epidemiological case clusters and outbreaks using a 25 mismatches threshold, and reveal a number of cryptic transmission chains, most of which are geographically restricted to one or a few adjacent countries. Subcultures of the vaccine strain PW8 differed by up to 20 cgMLST mismatches. Phylogenetic analyses revealed short timescale evolutionary gain or loss of the diphtheria toxin and biovar-associated genes. We devised a genomic taxonomy of strains and deeper sublineages (defined using a 500 cgMLST mismatches threshold), currently comprising 151 sublineages, only a few of which are geographically widespread based on current sampling. The cgMLST genotyping tool and nomenclature was made publicly accessible at https://bigsdb.pasteur.fr/diphtheria . Conclusions Standardized genome-scale strain genotyping will help tracing transmission and geographic spread of C. diphtheriae . The unified genomic taxonomy of C. diphtheriae strains provides a common language for studies into the ecology, evolution and virulence heterogeneity among C. diphtheriae sublineages.

Diphtheria in two pregnant in the context of the epidemic in Venezuela

Diphtheria is an acute infectious disease caused by the bacterium Corynebacterium diphtheriae that encodes diphtheria toxin (DT) in susceptible human subjects during an outbreak. Venezuela has experienced a widespread resurgence of diphtheria since early 2016.

Comparative tests of quality of bacteriological investigation with Corynebacterium diphtheriae isolation

The results of comparative experimental studies of identification of nontoxigenic C. diphtheriae strain by three different commercial laboratories are presented. A typical nontoxigenic strain of C. diphtheriae biovar mitis was used. For the studies, three lines of ten-fold dilutions of bacterial culture were prepared, followed by control planting on the medium and counting CFU/ml. In the experiment, tampons were pooled with a 24-hour bacterial culture of a nontoxigenic C. diphtheriae strain. Tampons were provided from three different laboratories - ∑-Transwab® with Ames liquid medium (from the first and second laboratories) and a viscose tampon with coal medium (from the third laboratory). After pooled, tampons were delivered to commercial laboratories. And as a result of the experiment, Corynebacterium spp. was identified in first laboratory (103 CFU/tamp), S. epidermidis (102 CFU/ml) - in second laboratory and nontoxigenic C. diphtheriae biovar gravis - in third laboratory. The study indicates that there is a need to the supervision of bacteriological investigations conducted in various laboratories. This will improve the quality of investigations on diphtheria infection and identify of diphtheria carrier, which is a reservoir of the causative agent of diphtheria, and will contribute to the maintenance of sanitary and epidemiological well-being in our country.