Strengthening the laboratory diagnosis of pathogenic<i>Corynebacterium</i>species in the Vaccine era

Sekar, Suresh Kumar Rajamani; Veeraraghavan, Balaji; Anandan, Shalini; Ragupathi, Naveen Kumar Devanga; Sangal, Lucky; Joshi, Sudhir

doi:10.1111/lam.12781

Cited by 16 publications

(10 citation statements)

References 74 publications

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“…In the NTTB type, the tox gene is detected by PCR and considered as toxigenic bacteria, but it is non-toxigenic phenotypically. Therefore, the toxigenicity detected by PCR should be further confirmed by the Elek test or Vero cell cytotoxicity phenotypically (7)(8)(9). Tables 1 and 2 show the advantages of PCR, especially in terms of sensitivity.…”

Section: Discussionmentioning

confidence: 99%

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Application of Polymerase Chain Reaction in Diphtheria Laboratory Examination: A Field Need

Sunarno¹,

Puspandari²,

Febriyana³

et al. 2021

Jundishapur J Microbiol

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Background: Indonesia is one of the five countries with the highest number of diphtheria cases worldwide. Diphtheria is caused by the toxigenic strains Corynebacterium diphtheriae, C. ulcerans, and C. pseudotuberculosis. The diphtheria-causing bacteria can be identified using conventional and molecular methods, including polymerase chain reaction (PCR) assay. We used the PCR assay as additional testing, because in island countries like Indonesia, specimen transport is a serious challenge to maintaining bacterial survival. Objectives: This study aimed to evaluate the PCR assay as additional testing to identify diphtheria-causing bacteria in the diphtheria laboratory. Methods: In this cross-sectional study, a total of 178 pairs of the throat and nasal swabs from diphtheria suspected cases and close contacts were collected from seven provinces in Indonesia in 2016. All samples were directly identified by the conventional method and multiplex PCR assay. Statistical analysis was conducted using the 2 × 2 tables to determine the sensitivity and specificity of both methods, while the χ2 test was used to examine the correlation between specimen examination delay and the differentiation of results. A P-value < 0.05 was considered as statistically significant. Results: Out of 178 examined samples, eight samples were identified as diphtheria-positive by both the conventional method and PCR assay, while nine samples were only detected by the PCR assay. All diphtheria-causing bacteria found in the positive samples were toxigenic C. diphtheriae. The diphtheria-causing bacteria were found in 27.6% of cases and 6.0% of close contacts using the PCR assay versus 13.8% of cases and 2.7% of close contacts using the conventional method. Statistical analysis showed that the PCR assay is about twice more sensitive than the conventional method. There was a significant correlation between the differentiation of results and > 72 hours’ specimen examination delay with a P-value of 0.04 (< 0.05). Conclusions: The PCR assay is more sensitive than the conventional method to identify diphtheria-causing bacteria and may be applied as additional testing to increase the positivity rate of diphtheria-confirmed cases in Indonesia as an archipelago country where geographical factors and specimen transport are real obstacles.

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Section: Discussionmentioning

confidence: 99%

“…However, to date, the WHO has not recommended PCR as a confirmatory method for diphtheria. The WHO recommends PCR as the screening method for bacterial toxigenicity that should be confirmed by the Elek test (4,(7)(8)(9). PCR cannot be used to identify bacterial toxigenicity of non-toxigenic tox gene-bearing (NTTB) type correctly.…”

Section: Introductionmentioning

confidence: 99%

Application of Polymerase Chain Reaction in Diphtheria Laboratory Examination: A Field Need

Sunarno¹,

Puspandari²,

Febriyana³

et al. 2021

Jundishapur J Microbiol

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“…Respiratory diphtheria can be lifethreatening. The pseudomembrane can cause difficulty swallowing and airway obstruction, and dissemination of the diphtheria toxin can cause necrosis at distant sites (myocarditis and neuritis) (2).…”

Section: Discussionmentioning

confidence: 99%

“…Cutaneous diphtheria may be caused by toxigenic or nontoxigenic strains. Infection appears as chronic, nonhealing sores or shallow ulcers and may develop in a preexisting wound (2). Frequently, cultures from these wounds are polymicrobial.…”

Section: Discussionmentioning

confidence: 99%

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The Brief Case: Nontoxigenic Corynebacterium diphtheriae in a Nonhealing Wound

2020

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A 46-year-old homeless man was transported to the emergency department (ED) after being found minimally responsive outside a public building. Upon evaluation in the ED, the patient was obtunded. He appeared to have sepsis with fever to 39.4°C and tachycardia to 168 bpm, but without hypotension. The patient had a full-thickness wound measuring 6 cm by 5 cm on the dorsal aspect of the distal left forearm with a pink wound bed and overlying purulent, yellowish exudate. The surrounding forearm was erythematous and edematous, with marked edema of the hand distal to the wound and decreased range of motion in the wrist and digits due to stiffness from swelling. There was no area of fluctuance, no bullae, no crepitus, and no exposed bone (Fig. 1). X ray of the extremity showed soft tissue swelling without bony erosion or subcutaneous gas. The patient reported he injects heroin and methamphetamines intravenously, intramuscularly, and intradermally multiple times a day. He has a history of chronic untreated hepatitis C infection and reported the wound on his left dorsal forearm was chronic, having been present for over 10 years with associated chronic osteomyelitis of the underlying radius. The patient had declined deep/surgical culture on multiple occasions. Previous superficial swabs of the wound bed had grown methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, and diphtheroids. At this encounter, exudative material in the wound bed was once again swabbed and sent for culture prior to starting empirical antibiotic therapy. No organisms or polymorphonuclear cells were observed on Gram stain of the exudate. Blood and urine cultures were negative for growth, and the suspected source of sepsis was superinfection of the chronic left upper extremity wound. The patient was treated empirically with intravenous vancomycin and cefazolin, which he received for 48 h. He had a brisk clinical improvement with normalization of his mental status and marked decrease in edema and erythema of the left upper extremity. He was discharged with prescriptions for doxycycline and cephalexin to complete a planned 14-day course of therapy. Cultures of the exudate collected from the wound grew equal quantities of S. aureus, S. pyogenes, and a diphtheroid (Fig. 2). Previous studies have found an association between S. aureus, S. pyogenes, and the presence of Corynebacterium diphtheriae in wounds; therefore, our standard laboratory practice is to identify diphtheroids, of any quantity, from wound cultures mixed with S. aureus and S. pyogenes (1). The diphtheroid was identified as Corynebacterium diphtheriae by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS; Bruker MALDI Biotyper, BDAL library with 7,311 main spectra [MSP]). Additional testing performed at the Washington State Public Health Laboratories confirmed the identification using traditional biochemical methods, and the Centers for Disease Control and Prevention (CDC) determined this was a nontoxigenic strain.

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Corynebacterium: Molecular Typing and Pathogenesis of Corynebacterium diphtheriae and Zoonotic Diphtheria Toxin-Producing Corynebacterium Species

Vieira

Ramos

Santos

et al. 2022

Molecular Typing in Bacterial Infections, Volume I

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Strengthening the laboratory diagnosis of pathogenicCorynebacteriumspecies in the Vaccine era

Cited by 16 publications

References 74 publications

Application of Polymerase Chain Reaction in Diphtheria Laboratory Examination: A Field Need

Application of Polymerase Chain Reaction in Diphtheria Laboratory Examination: A Field Need

The Brief Case: Nontoxigenic Corynebacterium diphtheriae in a Nonhealing Wound

Corynebacterium: Molecular Typing and Pathogenesis of Corynebacterium diphtheriae and Zoonotic Diphtheria Toxin-Producing Corynebacterium Species

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