Corynebacterium Diphtheriae Isolates Research Articles

A diphtheria outbreak in Johor Bahru, Malaysia: Public health investigation and response.

Diphtheria is an acute infectious disease caused by Corynebacterium diphtheriae. Although the incidence of diphtheria worldwide has rapidly declined following the largely successful diphtheria toxoid-based vaccines, concerns persist for those who were unvaccinated or incompletely vaccinated. In this report, we describe a recent diphtheria outbreak in Malaysia involving four confirmed diphtheria cases. The outbreak investigation efforts and epidemiological characteristics of a diphtheria outbreak in Malaysia are described. For all suspected cases, swabs were taken and sent for isolation of Corynebacterium diphtheriae and confirmation of toxigenic strains. The index case was a two-year-old child living with his family in a welfare home. Following contact tracing efforts and investigation for suspected cases, seven samples came back as culture positive for Corynebacterium diphtheriae. Confirmation of toxigenic strains was performed using PCR and Elek's test, which showed 100% correlation in positivity for four of the samples. All four confirmed cases were below 18 years of age, and three of them did not have complete vaccination history (two unvaccinated, one unknown). The index case eventually succumbed due to severe diphtheria with multiorgan failure while all the other cases were discharged healthy. In Malaysia, despite good vaccination coverage, sporadic diphtheria outbreaks still occur. The rising trend of cases reported over the recent years underscores the need to remain vigilant. Addressing pockets of unvaccinated children and potential waning immunity levels in the population remains pivotal.

Molecular Characterisation of Corynebacterium diphtheriae Isolates of Faucial Diphtheria Cases from Assam: A Cross-sectional Study

Introduction: Diphtheria caused by toxigenic Corynebacterium diphtheriae is an acute respiratory infection characterised by pseudomembrane formation in the throat. Although diphtheria is often reported sporadically across India, molecular characterisation of C.diphtheriae strains could play a crucial role in epidemiological investigations. Aim: The present study aimed at molecular characterisation of Corynebacterium diphtheriae isolates of faucial diphtheria cases from Assam, North-East India utilising Multi-Locus Sequence Typing (MLST). Materials and Methods: In this cross-sectional study, three isolates were obtained from three different cluster of cases that occurred across two districts of Assam, India for a period from November 2019 to June 2020. MLST of these three C.diphtheriae isolates were performed in Multidisciplinary Research Unit of Assam Medical College and Hospital by using the 7-gene MLST alleles of C.diphtheriae to determine the Sequence Types (ST). Results: The MLST of the three isolates of this study revealed two distinct STs, ST-588 and ST-576 with multi-clonal lineages with ST-466, reported in C.diphtheriae strains of North Kerala and ST-301 related strains of Bangladesh respectively. Conclusion: In spite of frequent reports of diphtheria cases from Assam, molecular typing of the C.diphtheriae strains found in North-Eastern region of India has not yet been performed. This is one of the initial investigations from this region of India to use MLST for typing C.diphtheriae strains. Therefore, studies related to molecular characterisation of C.diphtheriae strains found throughout India could immensely help in determining the clonality and diversity existing among these strains.

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

BackgroundSporadic 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.ResultsThis 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.ConclusionNon-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.

Short Communication: Identification and phylogenetic analysis of Corynebacterium diphtheriae isolates from Jakarta, Indonesia based on partial rpoB gene

Abstract. Yasmon A, Rosana Y, Usman D, Prilandari LI, Hartono TS. 2020. Short Communication: Identification and phylogenetic analysis of Corynebacterium diphtheriae isolates from Jakarta, Indonesia based on partial rpoB gene. Biodiversitas 21: 3070-3075. Indonesia is a developing country with the greatest potential of diphtheria, so accurate identification is needed to detect C. diphtheriae. The genetic relationship analysis is important to be determined so that this transmittable disease can be prevented. In this study, we reported the identification and phylogenetic analysis of C. diphtheriae based on partial rpoB gene. Twelve samples from throat swabs of diphtheria suspected patients from 2018 to 2019 were used in this study. The result of VITEK 2 ANC-Automated Testing identified that all isolates were C. diphtheriae. However, the identification based on partial rpoB gene analysis showed that only 10 out of 12 isolates were C. diphtheriae, while 2 other isolates were C. argentoratense. Of 10 C. diphtheriae strains/isolates, 2 strains were unique for Indonesia. Thus, it is needed to evaluate the accuracy of VITEK 2 ANC-Automated Testing and to conduct further comprehensive studies on the genetic relationships of C. diphtheriae strains based on multiple virulence genes, multilocus sequence typing and/or whole-genome analysis.

SENSITIVITY OF ERYTHROMYCIN AGAINST CORYNEBACTERIUM DIPHTHERIAE

Diphtheria is an acute infection disease caused by Corynebacterium diphtheriae. It remains a problem in Indonesia in a recent several years especially in East Java Province, which suffered from an outbreak of diphtheria in 2011. Erythromycin is the second line antibiotics therapy for diphteria if the patient is allergic to penicillin, also serving as a prophylactic and carrier therapy for contact diphtheria. Erythromycin has been used for diphtheria for a very long time, but there is little recent data on its sensitivity against C. diphtheriae. The purpose of this study is to identify whether Erythromycin still has a strong antibacterial activity against Corynebacterium diphtheriae by invitro test. This was a descriptive study which observed the sensitivity pattern of erythromycin against Corynebacterium diphtheriae using the Epsilometer test (etest) as a diffusion technique. Samples used in this study were 30 isolates of toxigenic Corynebacterium diphtheriae strain mitis and gravis at the Center for Health Laboratory (BBLK) Surabaya obtained during 2011 until 2014. We retrieved the data based on gender, age, and districts of patients for each of the samples then analyzed them descriptively. In this study, a sensitivity test of 30 toxigenic Corynebacterium diphtheriae isolates revealed that 27 (90%) were sensitive to Erythromycin (average Minimum Inhibitory Concentration/ MIC) <0.016 μg/mL and all were strain mitis, while 3 (10%) had intermediate sensitivity with MIC 1 μg/mL (all were strain gravis). No resistance result was found from the sensitivity test. According to the result, we conclude that Erythromycin still has a strong antibacterial activity against Corynebacterium diphtheriae.

Diphtheria in Metro Manila, the Philippines 2006-2017: A Clinical, Molecular, and Spatial Characterization.

BackgroundDiphtheria is a vaccine-preventable disease that persists as a global health problem. An understanding of the pattern of disease is lacking in low- and middle-income countries such as the Philippines.MethodsWe conducted a retrospective review of the clinical, microbiological, and epidemiological features of patients admitted with a clinical diagnosis of diphtheria to an infectious disease referral hospital in Metro Manila, the Philippines, between 2006 and 2017. Cases were mapped and the distribution was compared with population density. Corynebacterium diphtheriae isolates from between 2015 and 2017 were examined by multilocus sequence typing (MLST).ResultsWe studied 267 patients (range:12−54 cases/year) admitted between 2006 and 2017. The case fatality rate (CFR) was 43.8% (95% confidence interval, 37.8−50.0%). A higher number of cases and CFR was observed among children <10 years. Mortality was associated with a delayed admission to hospital and a lack of diphtheria antitoxin. Between 2015 and 2017 there were 42 laboratory-confirmed cases. We identified 6 multilocus sequence types (STs). ST-302 was the most common (17/34, 48.6%), followed by ST67 (7/34, 20%) and ST458 (5/34, 14%). Case mapping showed a wide distribution of diphtheria patients in Metro Manila. Higher case numbers were found in densely populated areas but with no apparent clustering of ST types.ConclusionsOur analysis indicates that diphtheria remains endemic in Metro Manila and that the infection is frequently fatal in young children. Improved vaccine coverage and a sustainable supply of diphtheria antitoxin should be prioritized.

Insights to the Diphtheria Toxin Encoding Prophages amongst Clinical Isolates of Corynebacterium diphtheriae from India

AbstractDiphtheria is a dreadful disease caused by Corynebacterium diphtheriae. Lysogenised bacteriophages carrying toxin gene in C. diphtheriae can make the strain toxigenic. However, such phage disseminates the toxin genes to other strains when it undergoes lytic phase. As little is known about the phage diversity in C. diphtheriae in India, the present study was undertaken to investigate the prophages integrated into the genome of 29 clinical isolates of C. diphtheriae using whole-genome shotgun sequencing. Amongst these isolates, 27 were toxigenic, while 2 were non-toxigenic strains. Of the 27 toxigenic strains, all harbored known phages carrying toxin gene and two other phages with unknown function. However, the two non-toxin strains did not harbour any of the phages in the genome. It is imperative to devise prevention strategies that hinder the dissemination of toxin by prophages, as it may increase the complications of diphtheria post-immunisation.

Genome-wide comparison of Corynebacterium diphtheriae isolates from Australia identifies differences in the Pan-genomes between respiratory and cutaneous strains

BackgroundCorynebacterium diphtheriae is the main etiological agent of diphtheria, a global disease causing life-threatening infections, particularly in infants and children. Vaccination with diphtheria toxoid protects against infection with potent toxin producing strains. However a growing number of apparently non-toxigenic but potentially invasive C. diphtheriae strains are identified in countries with low prevalence of diphtheria, raising key questions about genomic structures and population dynamics of the species. This study examined genomic diversity among 48 C. diphtheriae isolates collected in Australia over a 12-year period using whole genome sequencing. Phylogeny was determined using SNP-based mapping and genome wide analysis.ResultsC. diphtheriae sequence type (ST) 32, a non-toxigenic clone with evidence of enhanced virulence that has been also circulating in Europe, appears to be endemic in Australia. Isolates from temporospatially related patients displayed the same ST and similarity in their core genomes. The genome-wide analysis highlighted a role of pilins, adhesion factors and iron utilization in infections caused by non-toxigenic strains.ConclusionsThe genomic diversity of toxigenic and non-toxigenic strains of C. diphtheriae in Australia suggests multiple sources of infection and colonisation. Genomic surveillance of co-circulating toxigenic and non-toxigenic C. diphtheriae offer new insights into the evolution and virulence of pathogenic clones and can inform targeted public health actions and policy. The genomes presented in this investigation will contribute to the global surveillance of C. diphtheriae both for the monitoring of antibiotic resistance genes and virulent strains such as those belonging to ST32.

Molecular characterization of Corynebacterium diphtheriae isolates in Malaysia between 1981 and 2016.

Sporadic diphtheria cases in Malaysia have remained low in number since the 1990s. However, in 2016 a total of 31 cases were reported nationwide and to investigate this we performed molecular characterization of 30 Corynebacterium diphtheriae isolates collected from 1981 to 2016 using multilocus sequence typing (MLST). C. diphtheriae isolates were identified and biotyped using the API Coryne kit, while the toxigenicity was determined by PCR and the Elek test. All of the 2016 isolates belonged to biotype mitis, caused respiratory diphtheria and were toxigenic strains. MLST analysis identified 17 sequence types (STs), including 11 new ones. ST453 was the most common clone (7/30, 23.3 %), followed by ST141 (5/30, 16.7 %), ST451 (3/30, 10.0 %) and ST248 (2/30, 6.7 %). The clones identified in 2016 had not been detected in previous isolations and they were phylogenetically distinct. Our results suggest that the diphtheria cases in 2016 were caused by the emergence and spread of new clones in Malaysia.

Geographically Diverse Clusters of Nontoxigenic Corynebacterium diphtheriae Infection, Germany, 2016-2017.

From 2016 through the middle of 2017, the German Consiliary Laboratory on Diphtheria noted an increase in nontoxigenic Corynebacterium diphtheriae isolates submitted from cities in northern Germany. Many patients for whom epidemiologic data were available were homeless, alcohol or drug abusers, or both. After performing routine diagnostics and multilocus sequence typing (MLST), we analyzed isolates of sequence type (ST) 8 and previously submitted isolates by whole-genome sequencing. Results were analyzed for phylogenetic relationship by core genome MLST (cg-MLST) and whole-genome single-nucleotide polymorphism profiles. Next-generation sequencing–based cg-MLST revealed several outbreak clusters caused by ST8; the geographic focus was in the metropolitan areas of Hamburg and Berlin. To achieve enhanced analytical depth, we used additional cg-MLST target genes and genome-wide single-nucleotide polymorphisms. We identified patient characteristics and detected transmission events, providing evidence that nontoxigenic C. diphtheriae infection is a potential public health threat in industrialized countries.

Changes in MLST profiles and biotypes of Corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by nontoxigenic strains in Poland (1950\u20132016)

BackgroundCorynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated.MethodsA total of 62 C. diphtheriae isolates collected in the 1950s–1960s, 1990s and 2000–2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection.ResultsA total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004–2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti, but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis.ConclusionsDuring a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, nontoxigenic invasive and nontoxigenic non-invasive.

Re-emergence of diphtheria in Malappuram district, North Kerala, India

BACKGROUND AND OBJECTIVE: An outbreak of diphtheria was identified in Malappuram district, North Kerala, India, from July 2016 onwards as a sudden increase in the number of throat swabs with suspected diphtheria received in the Microbiology Lab of Government Medical College Manjeri, Malappuram district. The objective of this study was to confirm the outbreak and identify the organisms and their antibiotic sensitivity patterns.MATERIALS AND METHODS: A total of 554 throat swabs were received from July 2016 to June 2017 from neighbouring areas of Malappuram district for culture and sensitivity. Elek gel precipitation test and polymerase chain reaction of the isolates were performed at the State Public Health Lab, Thiruvananthapuram. All isolates of Corynebacterium diphtheriae possess diphtheria toxin gene. Antibiotic sensitivity tests were performed. Repeat swabs were not included in the study.RESULTS: Of the 29 (5.23%) confirmed cases, 18 (62%) were male and 11 (38%) were female. Fourteen (48.3%) cases were between 6 and 10 years of age with nine (64%) males and five (36%) females. Seven (24.2%) were between 11 and 15 years of age with four (57%) males and three (43%) females. Three (10.3%) were between 16 and 20 years of age (all males). Two (6.9%) cases from 26 to 30 years and one (3.4%) each from 21 to 25 years, 31–35 years and 36–40 years. All isolates were Penicillin sensitive.CONCLUSIONS AND DISCUSSION: Our study identified an upsurge of diphtheria in Malappuram district, North Kerala, among older children and adolescents. Most of them are partially immunised and immunity to diphtheria declines over time. Adults and adolescents thus become susceptible later in life. This emphasises the need for booster vaccination above five years in the endemic areas and making antidiphtheritic serum available in all major hospitals of these regions.

Resurgence of Diphtheria in North Kerala, India, 2016: Laboratory Supported Case-Based Surveillance Outcomes.

As part of national program, laboratory supported vaccine preventable diseases surveillance was initiated in Kerala in 2015. Mechanisms have been strengthened for case investigation, reporting, and data management. Specimens collected and sent to state and reference laboratories for confirmation and molecular surveillance. The major objective of this study is to understand the epidemiological information generated through surveillance system and its utilization for action. Surveillance data captured from reporting register, case investigation forms, and laboratory reports was analyzed. Cases were allotted unique ID and no personal identifying information was used for analysis. Throat swabs were collected from investigated cases as part of surveillance system. All Corynebacterium diphtheriae isolates were confirmed with standard biochemical tests, ELEK's test, and real-time PCR. Isolates were characterized using whole genome-based multi locus sequence typing method. Case investigation forms and laboratory results were recorded electronically. Public health response by government was also reviewed. A total of 533 cases were identified in 11 districts of Kerala in 2016, of which 92% occurred in 3 districts of north Kerala; Malappuram, Kozhikode, and Kannur. Almost 79% cases occurred in >10 years age group. In <18 years age group, 62% were male while in ≥18 years, 69% were females. In <10 years age group, 31% children had received three doses of diphtheria vaccine, whereas in ≥10 years, 3% cases had received all doses. Fifteen toxigenic C. diphtheriae isolates represented 6 novel sequence types (STs) (ST-405, ST-408, ST-466, ST-468, ST-469, and ST-470). Other STs observed are ST-50, ST-295, and ST-377. Diphtheria being an emerging pathogen, establishing quality surveillance for providing real-time information on disease occurrence and mortality is imperative. The epidemiological data thus generated was used for targeted interventions and to formulate vaccine policies. The data on molecular surveillance have given an insight on strain variation and transmission patterns.

Molecular Characterization of Corynebacterium diphtheriae Outbreak Isolates, South Africa, March-June 2015.

In 2015, a cluster of respiratory diphtheria cases was reported from KwaZulu-Natal Province in South Africa. By using whole-genome analysis, we characterized 21 Corynebacterium diphtheriae isolates collected from 20 patients and contacts during the outbreak (1 patient was infected with 2 variants of C. diphtheriae). In addition, we included 1 cutaneous isolate, 2 endocarditis isolates, and 2 archived clinical isolates (ca. 1980) for comparison. Two novel lineages were identified, namely, toxigenic sequence type (ST) ST-378 (n = 17) and nontoxigenic ST-395 (n = 3). One archived isolate and the cutaneous isolate were ST-395, suggesting ongoing circulation of this lineage for >30 years. The absence of preexisting molecular sequence data limits drawing conclusions pertaining to the origin of these strains; however, these findings provide baseline genotypic data for future cases and outbreaks. Neither ST has been reported in any other country; this ST appears to be endemic only in South Africa.

First Draft Genome Sequences of Malaysian Clinical Isolates of Corynebacterium diphtheriae.

ABSTRACTCorynebacterium diphtheriae has caused multiple isolated diphtheria cases in Malaysia over the years. Here, we report the first draft genome sequences of 15 Malaysia C. diphtheriae clinical isolates collected from the years 1981 to 2016.

Isolation of Toxigenic Corynebacterium diphtheriae from Chronic Suppurative Otitis Media

Background: A major shift in the pathogenic potential of Corynebacterium diphtheriae is being witnessed globally, consequent to the successful diphtheria immunization. However, its isolation from unconventional sites like middle ear has been rarely implicated in the available literature. Case Report: Here we describe a case of chronic suppurative otitis media (CSOM) in a fully immunized young adult patient from whom, Pseudomonas aeruginosa and Klebsiella pneumoniae were isolated as the major pathogens with simultaneous isolation of toxigenic Corynebacterium diphtheriae. The patient had no evidence of Corynebacterium diphtheriae infection on clinical examination, until the organism was incidentally isolated on culture suggesting the possibility of colonization or superimposed infection. Conclusion: Although, the condition was successfully managed with surgical and medical intervention with good outcome, this incidence warrants clinician’s attention towards unusual occurrence of a potentially dangerous pathogen. Considering the likelihood of its passive environmental shedding which may pose unseen threat of emergence of fatal diphtheria in the contacts and other susceptible local population, active screening for its carriage is advisable.

Pathogenic properties of a Corynebacterium diphtheriae strain isolated from a case of osteomyelitis.

Corynebacterium diphtheriae is typically recognized as a colonizer of the upper respiratory tract (respiratory diphtheria) and the skin (cutaneous diphtheria). However, different strains of Corynebacteriumdiphtheriae can also cause invasive infections. In this study, the characterization of a non-toxigenic Corynebacteriumdiphtheriae strain (designated BR-INCA5015) isolated from osteomyelitis in the frontal bone of a patient with adenoid cystic carcinoma was performed. Pathogenic properties of the strain BR-INCA5015 were tested in a Caenorhabditis elegans survival assay showing strong colonization and killing by this strain. Survival rates of 3.8±2.7 %, 33.6±7.3 % and 0 % were observed for strains ATCC 27010T, ATCC 27012 and BR-INCA5015, respectively, at day 7. BR-INCA5015 was able to colonize epithelial cells, showing elevated capacity to adhere to and survive within HeLa cells compared to other Corynebacteriumdiphtheriae isolates. Intracellular survival in macrophages (THP-1 and RAW 264.7) was significantly higher compared to control strains ATCC 27010T (non-toxigenic) and ATCC 27012 (toxigenic). Furthermore, the ability of BR-INCA5015 to induce osteomyelitis was confirmed by in vivo assay using Swiss Webster mice.

Microbiological and molecular characterization of Corynebacterium diphtheriae isolated in Algeria between 1992 and 2015

The objectives of this study were to undertake the microbiological and molecular characterization of Corynebacterium diphtheriae isolates collected in Algeria during epidemic and post-epidemic periods between 1992 and 2015. Microbiological characterization includes the determination of biotype and toxigenicity status using phenotypic and genotypic methods. Antimicrobial susceptibility was determined by the E-test method. Molecular characterization was performed by multi-locus sequence typing. In total, there were 157 cases of C. diphtheriae isolates, 127 in patients with respiratory diphtheria and 30 with ozena. Isolates with a mitis biotype were predominant (122 out of 157; 77.7%) followed by belfanti (28 out of 157; 17.8%) and gravis biotype (seven out of 157; 4.5%). Toxigenic isolates were predominant in the period 1992–2006 (74 out of 134) whereas in the period 2007–2015, only non-toxigenic isolates circulated (23 out of 23). All 157 isolates were susceptible to erythromycin, gentamicin, vancomycin and cotrimoxazole. Reduced susceptibility to penicillin G, cefotaxime, tetracycline and chloramphenicol was detected in 90 (57.3%), 88 (56.1%), 112 (71.3%) and 90 (57.3%) isolates, respectively. Multi-locus sequence typing analysis indicates that sequence type 116 (ST-116) was the most frequent, with 65 out of 100 isolates analysed, in particular during the epidemic period 1992–1999 (57 out of 65 isolates). In the post-epidemic period, 2000–2015, 13 different sequence types were isolated. All belfanti isolates (ten out of 100 isolates) belonged to closely related sequence types grouped in a phylogenetically distinct eBurst group and were collected exclusively in ozena cases.In conclusion, the epidemic period was associated with ST-116 while the post-epidemic period was characterized by more diversity. Belfanti isolates are grouped in a phylogenetically distinct clonal complex.

Epidemiological and Serological Study of Re-emerging Diphtheria in Dansai District, Loei Province, Thailand, June to October 2012

In July 2012, two fatal cases of diphtheria were reported from Dansai District of Loei Province, where had been free from diphtheria for a decade. An investigation was conducted to confirm the etiology, identify source of the outbreak and measure the prevalence of antibody to diphtheria toxin among the population. Medical records were reviewed. Active case finding and throat swab screening were done in all villages. Throat swab samples were sent for culture. Corynebacterium diphtheriae isolates were sent for toxin testing and a subset for multi-locus sequence typing (MLST). A serological survey of diphtheria antibody was done in 132 respondents in two villages. A total of 37 cases and 26 carriers were found. Total 18 (48.6%) cases were children. Two fatal cases (5.4%) were adults. All 16 (61.5%) children carriers had received the recommended doses of DTP or dT from the EPI program in the past. In the serological survey, 39.4% (52/132) had protective antibody, including 68.8% (11/16) of children and 35.3% (41/116) of adults. About 79% of people who had protective level received at least one dose of diphtheria toxoid. With MLST, three new subtypes were identified, including ST243, ST244 and ST245. Dansai outbreak was confirmed with the emergence of new pathogenic strains. A low proportion of sera (39.4%) had protective antibody level. A booster dose of diphtheria and tetanus toxoid should be considered.

Direct PCR: Alternative Diagnostic Method for Diagnosis of Diphtheria Rapidly, Easily and Cost Effective

Some diseases require immediate and appropriate treatment to decrease the fatality risk patients incident, for example diphtheria. Time to help patients is very crucial since delay of therapy may increase the mortality cases up to 20 times. In other hands, conventional diagnostic methods (the gold standard) for diagnosis of diphtheria is time consuming and laborious. Therefore, an alternative diagnostic method which is rapid, easy and inexpensive is needed. In this case, direct PCR has been proved to reduce time and cost in laboratory examination. This study aimed to develop direct PCR as alternative diagnostic method for diagnosis of diphtheria rapidly, easily, and inexpensive. Fifteen samples include 10 isolates of Corynebacterium diphtheriae (toxigenic) and 3 isolates of Corynebacterium non- diphtheriae (nontoxigenic) and 2 clinical specimens (throat swab) was examined by performing direct PCR method and a standard PCR method was used for optimizing the protocols. Result showed that direct PCR can be used to amplify target genes correctly as well as standard PCR. All of C. diphtheriae samples showed bands at 168 bp ( dtxR gene marker) and 551 bp ( tox gene marker) while no band appeared in others. Direct PCR detected at least 71 CFU/uL of bacterial cells in samples. We concluded that direct PCR can be used for alternative diagnostic method for diagnosis of diphtheria which is rapid, easy and cost effective. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4