Prevalence of leptospirosis in various risk groups.

Two hundred and twenty seven patients were included in the study. The test group included 55 patients of pyrexia of unknown origin (PUO), 42 veterinary workers, 38 hepatitis patients and 25 village farmers. The control group comprised of 27 Syphilis controls and 40 healthy controls. Of the total study entrants, 186 were tested for Leptospira antibodies by IgM ELISA and 41 by microscopic agglutination test (MAT). ELISA results of 45 patients were further tested by MAT for comparative evaluation. Out of 160 patients of the test group 56(35.0%) were positive for Leptospira antibodies. The positivity was 18(32.73%) amongst PUO patients, 15(35.71%) of the farm workers, 15(39.47%) of hepatitis patients and 8(32.0%) farmers. Leptospira antibodies were not detected in any of the controls. The antibody positivity was seen in 33(32.04%) of the 103 urban patients and 23(40.35%) of 57 rural patients. Out of 56 Leptospira cases, in 39(69.64%) history of animal contact was present. The common clinical features in these patients included fever in 51(91.07%), myalgia 48(85.71%), headache 42(75.0%), Anorexia 31(55.35%), Jaundice 24(42.86%) and nausea/vomiting in 21(37.5%). Of the 45 ELISA results compared with that of MAT, there was 86.67% agreement between the tests.

Haemagglutination, haemolysin production and serum resistance of proteus and related species isolated from clinical sources.

A total of 148 strains of Proteus and related species comprising of Proteus mirabilis (116), Proteus vulgaris (24), Providentia rettgeri (4), Providentia alcalifaciens (2), Providentia stuarti (1) and Morganella morganii (1), isolated from various sources, were examined for haemagglutination (HA), haemolysin production (HL) and serum resistance (SR). Maximum isolates were obtained from urine (47.30%) and pus (40.54%) and they were multidrug resistant. The sensitivity to Ciprofloxacin was 78.38%, Gentamicin: 62.84%, Cefotaxime: 29.73%, Norfloxacin: 22.97%, Tetracycline: 20.95% and Ampicillin: 6.76%. There were four commonest resistance patterns shown by 58.62% of Proteus mirabilis and 66.67% of Proteus vulgaris strains. Haemagglutination was shown by 91 (61.49%) strains, HL production in 126 (85.14%) strains and SR by 124 (83.78%) isolates. All the three i.e. HA, HL and SR were simultaneously present in 77 (52.27%) strains, any two were present in 40 (27.03%) strains and any one was positive in 30 (20.03%) strains. Thus in as many as 147 (98.32%) isolates, any one or more virulence factors were present. The virulence in commensal pathogen like Proteus is basically a multifactorial phenomenon. The presence of more virulence factors in one strain may increase its pathogenic ability. The evaluation of multiple virulence factors instead of one single parameter will be of greater help in assessing its pathogenic potential.

Virulence factors in uropathogenic E. coli.

Escherichia coli isolates from urinary tract infections often exhibit characters different from those isolated from normal faecal samples. Adherence to uroepithelial cells, nature of lipopolysaccharide O antigen and mannose resistant haemagglutination of human erythrocytes are some of the important virulence factors proposed in the pathogenesis of urinary tract infections caused by E. coli. In the present study a total of 100 strains of E. coli isolated from symptomatic cases of urinary tract infections (with significant bacteriuria) were studied for these properties. Faecal isolates of E. coli from adult healthy individuals were also studied as controls. As many as 58 uropathogenic strains showed high affinity for attachment to uroepithelial cells while 28 strains showed adherence at moderate degree. Agglutination of human erythrocytes was induced by as many as 70 uropathogenic strains while in 32 strains haemagglutination was not affected by D-mannose. In control group, adherence was observed in eight strains while 28 strains were haemagglutinating. Of these 28 strains, D-mannose resistant haemagglutination was observed in only one faecal strain. In uropathogenic group O4 was isolated with maximum frequency (12%) followed by O101, O135 and O6.

Extended spectrum beta-lactamase mediated resistance to third generation cephalosporins in Klebsiella pneumoniae in Nagpur, central India.

Out of 66 clinical isolates of Klebsiella pneumoniae, 17 showed resistance or decreased susceptibility to third generation cephalosporins (17 to cefotaxime, 16 to ceftriaxone, and 9 to ceftazidime) while the remaining 49 were sensitive by the disc diffusion method. The minimum inhibitory concentrations (MICs) of the third generation cephalosporins (3GC) for the strains ranged from 2-128 micrograms/ml by agar dilution method. Their sensitive phenotypes had zone diameters smaller (mean difference 3. 1 mm for ceftriaxone, and 6.5 mm for ceftazidime), and MICs > 10 fold higher than the corresponding values in the fully sensitive isolates. Resistance to cefotaxime was transferred to recipient Escherichia coli K12 strain in 15 isolates. All the resistant isolates were sensitive to imipenem but were variably sensitive to aminoglycosides, and quinolones. In all 17 resistant isolates extended spectrum beta-lactamase (ES beta L) was detected. The sensitivity testing systems may fail to recognise the potential ES beta L mediated resistance to 3GC. Hence ES beta L detection should be routinely undertaken.

Study of suspected plague cases for isolation and identification of Yersinia pestis.

A total of 62 suspected patients of plague were investigated for evidence of Yersinia pestis, by blood culture, lymph node aspirate culture, sputum culture, animal inoculation and serology for f1 antibodies against f1 antigen of Yersinia pestis. None of the samples was positive by direct smear examination and culture for Yersinia pestis, as well as for serology. The non positivity of the cultures is discussed.

Evaluation of cell mediated immunity in healthy contacts of leprosy.

The cell mediated immunity (CMI) was studied in 50 healthy contacts of leprosy patients and 50 age & sex matched non-contact controls by lepromin test and leucocyte migration inhibition (LMI) test using phytohaemagglutinin (PHA) and lepromin and its association with other risk factors in contacts was assessed. The lepromin positivity correlated well with LMI results. There was no difference in CMI in I, II and III degree of contacts. Amongst direct contacts lepromin test was positive in 67 per cent as compared to 92 per cent in indirect contacts while in LMIT migration index (MI) was significantly increased (0.66 +/- 0.20) in direct contacts. MI was also significantly increased (0.73 +/- 0.20) contacts of less than two years duration which decreased to 0.51 +/- 0.18 in contacts of more than five years duration. Lepromin positivity also increased from 60 per cent to 100 per cent in these contacts. The specific CMI was significantly suppressed in contacts of LL patients (MI:0.74 +/- 0.21) and BL patients (MI: 0.61 +/- 0.01) as compared to healthy controls. B.C.G. vaccinated individuals showed better CMI response. The findings in the study showed specific unresponsiveness to lepromin in LMI in leprosy contacts of less than two years duration, direct contacts, contacts of lepromatous spectrum of index patients and contacts not vaccinated with B.C.G. emphasizing that CMI status is an important parameter in identifying the contact population at the greater risk of acquiring leprosy.

Species distribution of clinical isolates of Staphylococci.

Species identification of 103 strains of staphylococci isolated from various clinical specimens revealed as many as eight species. S. aureus was the commonest isolate (57.28%) followed by S. epidermidis (17.47%). S. hominis (8.73%), S. saprophyticus (6.79%), S. intermedius, S. capitis and S. cohni (1.94% each) in decreasing order. They were mostly isolated from pus (41.74%) followed by urine (22.33%) and blood (18.44%) accordingly. Of the total isolates, 65 were coagulase positive while 38 isolates were coagulase negative. Phase typing of S. aureus strains revealed that 49 isolates were typable of which 17 isolates belonged to phase group III, 16 to phase group 1, 4 to group II and 3 belonged to group V while 9 strains could not be grouped. The antibiotic resistance pattern showed maximum resistance to penicillin (63.10%) while resistance was minimum with gentamycin (8.73%). Resistance to ampicillin (51.45%), cephazoline (51.45%), erythromycin (31.06+) and cloxacillin (18.44%) was low to moderate. The increasing recognition of pathogenic potential of various species of staphylococci and emergence of drug resistance amongst them denotes the need to adopt better laboratory procedures to identify and understand the diversity of staphylococci isolated from clinical material.

Characterisation of invasive Haemophilus influenzae isolated in Nagpur, central India.

A total of 14 invasive H. influenzae were isolated from 12 patients by culturing 621 samples of body fluids over a span of one year. Twelve non-replicate isolates were analyzed for their drug susceptibility and serotype distribution. Eight (66.7%) isolates were multiply drug resistant with resistance to ampicillin, chloramphenicol and cotrimoxazole in different combinations. All isolates were susceptible to cefotaxime and erythromycin. Serotype b accounted for 10 (83.3%) isolates while one each were type a and non-typeable respectively. A continuous surveillance of drug susceptibility and serotype distribution is important to determine changes in the behaviour of the organism over time.

Utilization of used human immunodeficiency virus ELISA microplates & surplus reagents for HIV antibody testing.

Used non-competitive enzyme-linked immunosorbent assay (ELISA) microplates were washed and reused to test samples and positive and negative controls, utilising the surplus reagents provided with the kit, which otherwise would have been discarded as useless after the entire 960 test kit had been utilized. These surplus reagents could be used for additional 220 tests over and above the recommended 960 tests per kit. A total of 839 unknown serum samples, 54 negative controls and 36 positive controls were tested using both washed and fresh (new) ELISA plates simultaneously. The optical density (OD) value of the control sera was within the prescribed limits in both the methods and 15 samples were found to be positive for HIV antibodies by the fresh plates whereas the washed plates showed 18 samples to be positive for HIV antibodies. None of the samples positive by fresh plates were negative by washed plates.

Enteropathogenic Escherichia coli diarrhoea in children and in young adults.

Enteropathogenic Escherichia coli are still important cause of diarrhoea in children as well as in adults population. In this study 550 cases of diarrhoea were studied for prevalence of enteropathogenic E. coli using culture and serological methods and final confirmation of strain was done from Central Research Institute, Kasauli. Out of 550 cases 385 strains of E. coli were isolated with isolation rate of typable strain being 70 percent. Common serotypes were 086, 055,0111, 028, 020, and rare strains like 0132, 0114, 0152, 0116, 088 were also reported from faecal specimen of diarrhoeal origin. Strains reported for the first time in central India were 0114, and 068.

Rapid detection of Vibrio cholerae 0139 in faecal specimens by coagglutination.

We compared the conventional culture method with the coagglutination (CoA) test for detecting V. cholerae 0139 antigen in a 4 h faecal enrichment culture. The CoA test reacted positively in all 13 culture positive stool specimens from patients with clinical cholera and negatively in all 23 culture negative specimens from non-diarrhoeal healthy controls. The test also did not show cross reaction with V. cholerae 01 antigen or with any of the enterobacterial antigens of the coliforms. The CoA test was found to be technically simple, rapid and reliable in diagnosing V. cholerae 0139 infection.

Study of diphtheria antibody levels in healthy population.

Diphtheria antibody levels were analysed in 200 healthy individuals by Indirect Haemagglutination test. The antibody titres in the age groups 1-5 and 6-10 years were well above the protective level. The titre declined with increase in age. In 11-20 years of age about 17.5 per cent, in 21-30 years of age 52.5 per cent and in persons above 30 years of age 82.5 per cent people had antibodies below protective level. Our results are comparable to studies from India and abroad. Emphasis is given for reconsideration of immunisation programme in higher age group.

Serotyping of pulmonary isolates of Candida albicans. A preliminary study.

A total of twenty strains of Candida albicans isolated from chronic pulmonary lesions were subjected to serotyping procedure adopting the conventional agglutination reactions. Prior to serotyping all the twenty strains were isolated on at least three different occasions and were identified by the standard accepted criteria (germ tube production, colony morphology on cornmeal Tween 80 agar and sugar fermentation reactions). Of the twenty strains, four strains belonged to serotype B and the remaining sixteen had the agglutination profile consistent with serotype A. The serotyping was undertaken with locally raised antisera against serotype A and serotype B. The proposed serotyping procedure has a definite potential in the epidemiological investigations of Candida albincans.

Changing bacteriological profile of cholera in Nagpur, 1991-93.

In Nagpur (Maharashtra) during the period 1991-93, Vibrio cholerae serogroup 01 predominated in 1991 (94.7%) and 1992 (86.4%) but significantly declined in 1993 (10.7%). Serogroups 02-0138 were infrequently encountered. A new strain V. cholerae serogroup 0139 emerged in 1993 and accounted for 89.3 per cent of the total vibrios isolated in the year. Replacement of the endemic 01 strain by the new 0139 strain was observed.

Effect of H37Ra on PHA-induced migratory inhibition of leucocytes in patient of tuberculosis.

Eighty nine cases of active pulmonary tuberculosis were classified into four stages depending on the clinical extent of disease. Leucocyte migration inhibition test (LMIT) was done using mitogen phytohaemagglutinin (PHA) and H37Ra specific antigen. Normal PHA responses were observed in all clinical stages while specific immune response in relation to inhibition of leucocyte migration decreased from stage I to stage IV. Effect of H37Ra on PHA induced release of lymphokine was studied by mixing the two and comparing the percentage migratory inhibition of the mixture with that of PHA alone. Increased or decreased values with mixture compared to those with PHA alone were regarded as enhancement or inhibitory effect respectively. Median percentage effect of H37Ra on PHA induced migratory inhibition was found to be inhibitory in first three stages and controls while enhancement effect was observed in stage IV. A total of 22 cases in all stages showed enhancement effect while 48 cases showed inhibitory effect. The possible mechanism of enhancement or inhibitory effect are discussed.

Antibiogram, phage types & biotypes of Salmonella typhi isolated in Nagpur.

S. typhi was isolated from 241 patients of pyrexia between July 1990 and March 1991. Multiple drug resistance was observed in 220 (91.3%) strains, the commonest pattern of drug resistance being ACCoT (49.4%). Predominance of phage type E1 in 196 (81.3%) strains and biotype I in 225 (93.4%) strains was observed. All ACCoT strains belonged to phage type E1 and all strains of phage type E1 belonged to biotype I.