MICROBIOLOGICAL STUDY OF DIPHTHERIA
Kaenat Tanveer (134), Faryal Arshad (205) & Hira Aslam (153)
Faculty of Pharmacy, University Of Sargodha, Sargodha.
A man was diagnosed at District Headquarter Hospital, Faisalabad with cutaneous diphtheria. The man had experienced persistent ulcer infections of skin. He was in good condition. Corynebacterium diphtheria which produces the toxin was grown from a wound specimen. MALDI-TOF test and PCR was carried out for detection of C.diphtheria. His case history reveals that he received a vaccine booster of diphtheria dose in 2005. Clinical study of some of the close contacts showed an asymptomatic person who was colonized with non-toxigenic Corynebacterium diphtheria. Physician prescribed different medicines after which the patient recovered in 14 days.
KEY WORDS: Cutaneous Diphtheria, Pathophysiology, Symptoms, Diagnosis
CORRESPONDING AUTHOR: Email: [email protected]
Kaenat Tanveer, Faculty of Pharmacy, University Of Sargodha, Sargodha, Pakistan.
Diphtheria is a toxin mediated disease. This disease is caused by Corynebacterium diphtheria. It is aerobic gram positive bacillus. The possible severity of disease is generally related to extent of that local disease (1). The toxins after absorption, affect different organs and tissues distant from site of invasion. Susceptible person may acquire toxigenic diphtheria bacilli (2). The toxin produced by this organism inhibits protein synthesis at cellular level and causes tissue destruction. Its diagnosis is done on the basis of clinical trials since its really imperative to begin the presumptive therapy quickly. Lesion culturing is done to confirm diagnosis. It’s difficult to take swab of pharyngeal area especially any discolored area (3). Tellurite culture medium is used because it provides selective benefit for growth of this bacteria. Treatment is done with the help of erythromycin or by injection (max. 2g/day) given for 14 days or penicillin G, intramuscularly. Elimination of organism can be seen by two negative cultures when therapy is completed (4, 5, 6 ).
A 20 year old boy was presented in emergency of DHQ Faisalabad with history of skin ulcer that lasted approximately five to six weeks. The ulcer was located in the right big toe. The patient has similar leg ulcer which lasts for several weeks from November, 2013.He could also remember some kinds of insect bites and also some traumas. The patient healed from these ulcers after he had received amoxicillin/clavulanic acid for one week orally, as prescribed by physician. A treatment is given consisting of dicloxacillin tablets 500mg four times daily. The patient was suspected by an infection caused by pyogenic bacteria and a wound specimen was done with aerobic culturing and screening for meticillin- resistant Staphylococcus aureus. After culturing the specimen for 24 hours, incubation on blood agar and chocolate agar was done and abundant growth of pure cultures of small, 1-2mm diameter, white, non-haemolytic colonies mimicking normal bacterial flora was observed. A wet mount demonstrated short rods. By using matrix assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF) on Micro flex LT mass spectrometer with biotyper, the isolate was found to be Corynebacterium diphtheria. On selective medium of Tins Dale the isolate showed deep brown colonies after 24 hours of incubation. The isolate was sent to Sir Agha Khan Laboratories and diphtheria toxin tox gene was detected in polymerase chain reaction (PCR).Production of Diphtheria toxin was analyzed and reported positive. After diagnosing Corynebacterium diphtheria the treatment was changed and oral phenoxymethylpencillin tablet 660 mg were given four times daily. The patient’s vaccination history was studied he received a diphtheria vaccine booster dose in 2004. He was also prescribed oral erythromycin capsules 500 mg two times daily for eight days. The patient recovered in 14 days.
This disease is endemic in many regions and physician should be well aware of the possibility of this disease in patients. Corynebacterium diphtheria can survive up to 3 months. Diagnosis of diphtheria in this case emphasises on the importance of detailed clinical information given by the examining physician. MALDI-TOF MS is easy to use; it’s cost effective and enables rapid species identification in a couple of minutes (2). The techniques mentioned above are reliable for identification of C. diphtheria. Currently identified species of all the toxigenic Corynebacterium species proposed an algorithm for the reliable identification and study of C. diphtheria incorporating MALDI-TOF MS and PCR. This workflow was very effective and helpful in our case. The collaboration of laboratory, performing PCR and local medical officer proved very efficient. These strains of C.diphtheria are recently recognised as emerging pathogens. These strains, can be converted to toxigenicity by infection with lysogenic phage (7).
Rational use of antibiotics reduces the risk. A vaccination series will reduce the risk however doesn’t eliminate carriage of C.diphtheria in pharynx or nose.
‘ A complete vaccination series reduce the risk of developing diphtheria.
‘ Rational use of antibiotics will reduce the risk.
‘ Combined diphtheria and tetanus booster called TD booster is also given for maintain protection.
We are very thankful to our revered professor Dr. Taha Nazir (course director of Pharmaceutical Microbiology, Faculty of Pharmacy, University Of Sargodha, Sargodha, Pakistan) and Dr. Fouzia Khalid (M.B.B.S, W.M.O, DHQ Faisalabad).
1. Funke G, Frommelt M, von Graevenitz A. ‘Emergence of non-toxigenic C.diphtheriae’, 2000, p.477-80.
2. Seng.P, Rancour C, ‘Ongoing revolution in bacteriology: Routine identification of bacteria by laser desorption matrix assisted ionization time-of-flight mass spectrometry. Clinically Infectious Disease’, 2009, p.543-51.
3. Andell, dell Man, ‘Douglas and Bennett principles and practice of infectious diseases’, 7th ed,2010, p. 2677-93.
4. Crosby, W. HD. Diphtheria, bacilli in floor. 2010, p. 656-9.
5. Schuhegger, Lindenmayer M, Kugler R, Singh A. ‘Detection of toxigenic C.diphtheriae and Strains by a Novel Real-Time PCR’, 2008, p.2832-3
6. Levinson, Warren, ‘Review Of Medical Microbiology and Immunology’ 13th Edition, McGraw Hill Publication, 2014.
...(download the rest of the essay above)