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Biomedical subjects

K N Brahmadathan

Publications and source records attributed to K N Brahmadathan.

At least 19 recordsLinked to original sources

Long-term preservation of streptococci.

Strains of 12 T types of group A streptococci preserved by sand desiccation and stored at 4 degrees to 10 degrees C were regularly sub-cultured to check their viability. For this, streptococci coated onto sand particles mixed with sterile sheep blood were inoculated into Todd-Hewitt broth with added blood and incubated for 24 to 48 h. Checking for viability every six months showed that group A streptococci could be preserved by this method for 21 yr. Our study shows that sand desiccation is a convenient and cheap method for the long-term preservation of streptococci in laboratories where other methods of preservation are not feasible on a regular basis.

Bacteriological Techniques

Beta haemolytic group A streptococci causing urinary tract infection.

OBJECTIVE: To describe the clinical and laboratory findings in patients with Group A streptococci (GAS) bacteriuria. PATIENTS: Patients with GAS bacteriuria seen in a tertiary care hospital in southern India between 1988 and 1993 were identified. Data were collected from the hospital records. RESULT: GAS were isolated from 15 women and 11 men. Clinical data were available for 24 of these. The condition presented as asymptomatic bacteriuria (nine patients), dysuria or frequency (12), and fever without localizing signs (three). All infections occurred in individuals with systemic or local conditions predisposing to urinary tract infection. All patients responded well to antimicrobial therapy. CONCLUSION: GAS bacteriuria is rare and occurs only in individuals with other predisposing conditions. Patients with this infection respond well to therapy.

Adult

Maxillary sinus fusariosis in immunocompetent hosts.

We report the first known cases of Fusariosis of maxillary sinus with granuloma and oro-antral fistula in two immunocompetent hosts. Fusarium solani was demonstrated in the direct microscopic examination and isolated in heavy growth from the biopsy materials. Both these patients were successfully treated with oral ketoconazole (200 mg daily) for three weeks followed by a Caldwell-Luc operation. Ketoconazole was continued for two months post-operatively.

Adult

Fallacies in the interpretation of Paul-Bunnel Davidsohn differential test.

Serological findings in five cases where Paul-Bunnel Davidsohn (PBD) test results were misleading, are presented. Three patients' with Chronic renal disorder and positive PBD test had specific serology results, signifying Cyto Megalo Virus infection. A fourth patient with Hepatitis B Virus infection also had positive PBD test. Forssman type of antibody response was demonstrable in a boy with recent Epstein-Barr virus infection and high Cyto Megalo Virus antibody titres.

Adult

Biological characterisation of group F streptococci causing human infections.

Fifty five strains of group F streptococci (GFS) isolated from clinical samples of 53 patients with diverse diseases, were characterised by a battery of physiological tests. Among them 37 (67%) were Streptococcus anginosus F, 14 (25%) were Strep. intermedius, two of which were mannitol positive and 4 (7%) were Strep. constellatus. Determination of minimum inhibitory concentrations of penicillin, erythromycin, ampicillin, gentamicin and cefazolin showed that despite their biochemical heterogeneity, all strains were uniformly susceptible to these antibiotics. Except for bacteraemia, other diseases due to GFS responded well to surgical drainage and/or antibiotics.

Bacteremia

Speciation of viridans streptococci & their significance in human infections.

Sixty strains of viridans streptococci recovered, from various infections, encountered in a large referral Hospital in Tamil Nadu (south India) from December 1983 to May 1985 were characterised by conventional tests. Of these, 57 (95%) belonged to four species viz., Sanguis II, Mitis, Intermedius and Constellatus. Of the 40 strains that were assessed for their clinical significance, 23 (57.5%) were found to be either significant or of suggestive significance. The study suggested viridans streptococci are not particularly virulent pathogens. But local/systemic factors were found to predispose the subjects to this infection.

Humans

Importance of group G streptococci in human pyogenic infections.

Streptococci that belong to groups other than A are involved in a variety of human infections. In the present study, we report the pyogenic infections associated with group G streptococci (GGS), observed at the Christian Medical College Hospital, Vellore, Tamil Nadu, India. Of 2314 beta-haemolytic streptococci isolated from 31,857 pus specimens processed during the period 1975-1986, GGS accounted for 338 (14.6%). Twelve of these were grown in pure culture. The clinical conditions associated with them included pyogenic arthritis, osteomyelitis, paravertebral sinus and an abdominal burst. Clinical analysis of 99 of 125 patients with GGS, grown in mixture with another organism or skin contaminants, showed that 59% of them were from surgical wound infections, diabetic lesions or wound infections in leprosy patients. Surgical management and antibiotic treatment resulted in full recovery of these clinical conditions.

Abscess

Detecting bacteriuria in a primary maternal and child health care programme.

Urinary tract infection in pregnancy has not been adequately dealt with in developing countries, though its consequences are well recognised. This is primarily because of constraints on resources coupled with a lack of technological infrastructure. An evaluation of the Griess test for the mass screening of urinary tract infection among antenatal women was carried out prospectively using a case-control method. The Griess test was found to be a valid, reliable, and economical screening test for urinary tract infection which can be integrated into a primary maternal and child health care programme.

Bacteriological Techniques

Use of enzymes in typing group A beta-haemolytic streptococci.

A series of 698 strains of group A beta-haemolytic streptococci (GAS) isolated from children with streptococcal pyoderma was tested for production of serum opacity factor (OF) and nicotinamide adenine dinucleotide glycohydrolase (NADase). OF was produced by 37% of strains and 40% produced NADase. Classification based on various combinations of OF and NADase reactions showed that 58% belonged to enzyme group el and 34% to e2. Correlation with T and M types showed the possible use of this means of classification as an epidemiological marker for GAS. The specificity of such a system in the further classification of various T types of GAS in epidemiological studies, in the light of antigenic variation among M types, is described.

Bacterial Typing Techniques

Epidemiology of streptococcal pyoderma in an orphanage community of a tropical country.

A group of 89 children residing in an orphanage, situated about 12 km from Vellore town, Tamil Nadu, India, were surveyed for streptococcal pyoderma, every month, from October 1976 through to December 1978. The prevalence rate of pyoderma as defined by the isolation of group A streptococci (GAS) was 10.1% with monthly variations from 2.1% to 17.1%. Three meteorological data, namely, temperature, humidity and rainfall did not show any significant relationship with seasonal patterns of pyoderma. However, a hot and humid climate, prevalent for most of the year in Vellore, may be linked to the endemicity of this condition. Studies performed on a limited number of GAS strains showed a variety of M types in the lesions. During this survey, poststreptococcal glomerulonephritis (PSGN) was not detected. In one child, a moderate albuminuria was observed; this resolved subsequently. We attest that an active surveillance of detection and treatment of pyoderma in a highly susceptible population plays an important role in the prevention of PSGN.

Adolescent

The reliability and rapidity of the coagglutination technic and its comparison with precipitin technic in the grouping of streptococci.

Three methods of the grouping of 170 strains of beta-hemolytic streptococci belonging to Groups A, B, C, F, and G by capillary and agar-gel precipitation using Lancefield extract and by coagglutination of antibody-coated protein A-containing staphylococci were compared. Capillary and agar-gel precipitin technics correctly grouped all 170 strains, with no cross-reaction. One hundred sixty-nine out of the 170 strains were also correctly grouped by the coagglutination technic, and the one strain with a cross-reaction was correctly grouped after blood--agar subculture. Although 20 of the 170 strains showed minor cross-reactions by the coagglutination technic, the specific groups were easily and unquestionably detected, and the minor cross-reactions were easily overcome. A rapid method of grouping by coagglutination technic using 4--6-hour broth culture, done on 75 strains, showed that 73 strains could be correctly grouped by the rapid method and two after overnight incubation. Thus, the coagglutination technic of grouping was found to be easy, reliable, and economical, and could be adopted in any routine diagnostic laboratory as a rapid grouping procedure.

Agglutination Tests