Spectrum of antibiogram against pathogens related to respiratory tract infections with a special reference to ceftibuten: a multicentric study.

In a multicentric study at several leading hospitals of this country, microbiological assessment was carried out in 500 specimens from patients suffering from respiratory tract infections (RTIs; both upper and lower) for a period of 6 months from January, 1999 to June, 1999. The antibiotic sensitivity study was done in 201 isolates from 500 different specimens of throat swab, postpharyngeal swab, sinusitis drainage fluid, sputum, broncho-alveolar lavage (BL), etc. Ceftibuten, an orally active third generation cephalosporin showed encouraging results when compared with seven other selected antibiotics used for RTI. The majority of the patients with acute or chronic RTIs showed an excellent in vitro response to ceftibuten in the analysis of the isolates. Seventy to ninety per cent of the isolated respiratory pathogens were found to be sensitive to ceftibuten in vitro; which offers a promising alternative to other antibiotics included in this study.

Cyclospora infection in acquired immunodeficiency syndrome.

BACKGROUND: Diarrhea is a common clinical manifestation of human immunodeficiency virus (HIV) infection. The important protozoan pathogens causing diarrhea include cryptosporidium, microsporidium, Isospora belli and cyclospora besides giardia lamblia and entamoeba histolytica. OBJECTIVE: The objective of the present study was to determine the incidence of cyclospora (a coccidian protozoan) infection in HIV infected patients. METHODOLOGY: Faecal smears were stained by modified acid fast staining method to demonstrate oocysts of cyclospora. RESULTS: Out of 334 faecal specimens which were studied, cyclospora were identified in 22 cases (6.6 percent); and in 50 percent of the patients, there was a mixed infection with another protozoan parasite namely cryptosporidium. CONCLUSION: Identification of this parasite is important because cyclosporiasis can be treated with trimethoprim-sulfamethoxazole. Outbreaks of cyclospora infection have been linked to waterborne transmission. Though adequately chlorinated water is free of coliforms, it can still contain cyclospora.

Standardization of a dot blot immunoassay for antigen detection in cases of pulmonary tuberculosis & its evaluation with respect to the conventional techniques.

A simple dot (blot) ELISA test for detecting tubercular antigen in sputum samples of patients of pulmonary tuberculosis has been standardized using nitrocellulose paper. The sensitivity of the assay is 20 ng/ml. The cut-off value was 80 ng/ml. Of the 1042 patients in the study group, the percentage positivity by smear and culture was 54.51 and 57.93 per cent respectively; 68.7 per cent of the ELISA positives were confirmed by smear. The dot blot ELISA could be used as a rapid and specific test as it not only picked up 88.88 per cent of the smear positive, culture positive cases but also 81.89 per cent of the smear negative, culture positive cases. If the results of smear and dot blot ELISA are combined, 91.08 per cent of the culture positive cases were picked up as positive. If such a noninvasive test is commercialized and used in conjunction with smear, the pick up rate of tuberculosis cases will improve considerably.

Pattern of secondary acquired drug resistance to antituberculosis drug in Mumbai, India--1991-1995.

A retrospective observational study was conducted to find out whether secondary acquired drug resistance to isoniazid and ethambutol is high and to rifamycin and pyrazinamide is low, as is commonly believed in India. There were 2033 patients, whose sputum samples (6099) were reviewed from a specimen registry of the microbiology laboratory for the years 1991 to 1995. Of these, 521 (25.6%) patients [335 males and 186 females; age ranged from 11 to 75 years] had sputum positive culture and sensitivity for acid-fast bacilli (AFB). The drug resistance patterns in our study were: isoniazid (H) 15%, rifamycin (R) 66.8%, pyrazinamide (Z) 72.2%, ethambutol (E) 8.4%, streptomycin (S) 53.6%, cycloserine (C) 39.2% kanamycin (K) 25.1% and ethionamide (Eth) 65.3%. The resistance to streptomycin showed a significant fall over a year while there was a rise in resistance to cycloserine and kanamycin which is significant. The rate of secondary acquired resistance of isoniazid and ethambutol was low, and the rate of secondary acquired resistance to rifamycin and pyrazinamide was high, which is contarary to the common belief regarding these drugs in India. This implies that isoniazid is still a valuable drug in the treatment of multidrug resistance in India.

Comparative pathogenicity of trichomonas vaginalis isolated from symptomatic & asymptomatic cases.

Pathogenicity of 19 isolates of T.vaginalis obtained from vaginal specimens were studied in the murine model by intraperitoneal route. Sixteen isolates were recovered from the females with various clinical conditions and 3 isolates were from normal healthy females. Pathogenicity level of these isolates were studied by inoculating 5 mice per isolates through intraperitoneal route and the animals were sacrificed on tenth day post-inoculation. In general, all the isolates recovered produced infection in mice. On comparison with the reference strain obtained from Hoechst India Ltd., seven isolates recovered from symptomatic cases and one strain from healthy females produced severe infection in mice. Though variation in pathogenicity level was observed among the isolates, a definite correlation between clinical picture in natural host and pathogenicity in mice was not observed.

Serogroup prevalence of Shigellae in Bombay.

Prevalence of Shigellae serotypes in Bombay was studied from June 1988 to May 1991. A total of 2758 faecal specimens were collected from paediatric patients (< 12 yrs) with acute gastroenteritis. A total of 90 Shigella were isolated giving the isolation rate of 3.2%. Shigella flexneri was the predominant serogroup (73.3%) followed by Shigella dysenteriae (16.6%). All the isolates were sensitive to nalidixic acid. Eighty percent of the Shigellae were multidrug resistant. Present data were compared with the study carried out during the period of 1983-87 from the same institute. A change in the serogroup prevalence was noted wherein Shigella flexneri dominated over Shigella dysenteriae since 1985. Increase in resistance to ampicillin and cotrimoxazole was seen in Shigella flexneri strains as compared to previous years.

Antibiotic resistance pattern and R-plasmids of Acinetobacter calcoaceticus subsp. anitratus.

During a 6 month period from March 1990 to August 1990, a total of 159 strains of Acinetobacter calcoaceticus subsp. anitratus were isolated from various samples and studied for antibiotic resistance pattern to 12 drugs by Kirby-Bauer method. Ceftazidime and Netilmycin were the most sensitive drugs followed by Cefotaxime, Norfloxacin and Augmentin. All the strains were resistant to Chloramphenicol and Tetracycline. Commonest pattern of resistance was ACGKSTSu. Forty eight isolates were tested for R-plasmids by conjugation experiments using Nalidixic acid resistant E. coli K12F-Lac+ as the recipient strain. The incidence of R-plasmids was 81.25%.

Prevalence of nocardiosis and use of Modified Thayer Martin medium.

5 cases of pulmonary and 1 case of cerebral nocardiosis in the form of abscess caused by Nocardia asteroides were detected in a study of 498 clinical specimens from 428 patients of suspected tuberculosis and mycoses, giving an overall prevalence of 1.4 percent. Modified Thayer Martin Medium was useful for recovery of two isolates of N. asteroides from 100 patients. These isolates also grew on other media but on MTM, no hampering admixture of commensals occurred.

In vitro adhesiveness of Gardnerella vaginalis strains in relation to the occurrence of clue cells in vaginal discharge.

G. vaginalis was isolated from 52.4 per cent patients with non-specific vaginitis. The haemagglutinating activity of G. vaginalis was strongest with human 'O' red cells and weaker reactions were observed with sheep and chick erythrocytes. Haemagglutinating activity of G. vaginalis with human 'O' cells (1:16 titre) could be correlated with clue cells in vaginal discharge in 73 per cent patients while in lower titres, this correlation was not observed.

Detection of Chlamydia trachomatis antigen & Toxoplasma gondii (IgM) & Mycoplasma hominis (IgG) antibodies by ELISA in women with bad obstetric history.

A total of 365 non pregnant women with bad obstetrics history (BOH) were studied with a control group of 100 women who had delivered full term clinically normal infants. The presence of C. trachomatis antigen and T. gondii (IgM) and M. hominis (IgG) antibodies was assessed by ELISA test. C. trachomatis antigen was detected in 28.2 per cent of women with BOH whereas T. gondii and M. hominis specific antibodies were found in 43.83 and 27.1 per cent respectively, these were highly significant (P < 0.001) in comparison with the control group. In case, facilities for culture are not available then detection of antigen and IgM class of antibodies by ELISA can pinpoint current infection.

Comparative pathogenicity of Trichomonas vaginalis isolated from symptomatic and asymptomatic cases.

Pathogenicity of 19 isolates of Trichomonas vaginalis obtained from vaginal specimens were studied in the murine model by intraperitoneal inoculation. Sixteen isolates were recovered from the females with various clinical conditions and 3 isolates were from normal healthy females. Pathogenicity level of these isolates were studied by inoculating 5 mice per isolate through intraperitoneal route and the animals were sacrificed on the 10th day post-inoculation. In general, all the isolates recovered produced infection in mice. On comparison with the reference strain obtained from Hoechst India Ltd., seven isolates recovered from symptomatic cases and one strain from healthy females produced severe infection in mice. Though variation in the pathogenicity level was observed among the isolates, a definite correlation between the clinical picture in the natural host and pathogenicity in mice was not observed.

Enzyme-linked immunosorbent-assay for antigen detection in tuberculous meningitis.

Two systems of Competitive Enzyme linked immunosorbent assay (ELISA) were developed to detect Mycobacterial antigen in cerebrospinal fluid (CSF) for the diagnosis of tuberculous meningitis (TBM)--one by using indigenously prepared Anti-M.tuberculosis H37Rv-Penicillinase conjugate (Method I) and another by using commercially available Anti M. bovis BCG-Horse Radish Peroxidase (HRP) conjugate--(Method II). The tests were used to analyse CSF of 148 patients clinically confirmed as having TBM and 278 control subjects. By using > or = 10 ng/ml as the cut-off value for Method I and > or = 1 ng/ml as that for Method II, the specificity for both were 100% and positivity was 79.73% and 67.57% respectively. A follow up study in 26 TBM cases after 2 weeks (16 cases), 4 weeks (13 cases) and 4-12 months (10 cases) of antituberculous treatment revealed that mycobacterial antigen persisted in the majority of cases even after 4 weeks of the treatment.

Actinomyces species associated with intrauterine contraceptive devices and pelvic inflammatory disease.

Swabs from 112 removed intrauterine contraceptive devices (IUCD), endocervical swabs from these women and from 65 women with pelvic inflammatory disease (PID) were studied for actinomyces, using direct fluorescent antibody test and culture. Endocervical swabs from 50 control subjects were also studied. Actinomyces species could be detected in 23 (20.5 percent) of IUCD wearers and 8 (12.3 percent) of patients with PID. In control cases, no actinomyces were detected. The isolation rate using a selective medium (Actino Blood Agar) was 71.4 percent. Actinomyces israelii, Actinomyces naeslundii and Actinomyces viscosus were isolated.

Microbiological study of mycetoma patients from Bombay with special reference to actinomyces immunofluorescence.

17 of the 21 clinically diagnosed mycetoma and actinomycosis cases studied yielded positive cultures. Foot, leg, inguinal region, chest wall, jaw and scalp were the affected sites. 15 of the patients were from Bombay, 13 of them had infection due to Nocardia species and 2 had Actinomyces israelii infection. The other two patients from South India had Madurella mycetomi infection. N.brasiliensis was commonest isolate (8). Other isolates were N.asteroides (2), N.pelletieri (2), N.caviae (1) and A.israelii (2). A direct fluorescent antibody test to detect actinomyces was used in selected cases (4). Two of whom gave positive immunofluorescence with A.israelii FITC labeled globulin, in primary smears as well as in cultures.

Retrospective treatment analysis of Salmonella infections.

Twenty four culture proved and nine postmortem histopathology proved cases of enteric fever were analysed retrospectively with special interest in use of various antisalmonella agents. Chloramphenicol resistance was noted in 91.7% and yet 70% of all patients received chloramphenicol alone or in combination with another antisalmonella agent. Time required for remission of fever with chloramphenical, cotrimoxazole and ciprofloxacin was 4.5, 4.1 and 6.9 days respectively. An interesting feature noted in post-mortem histopathology proved cases was enteric carditis which was documented on postmortem examination of the heart in three out of four patients who died of peripheral circulatory failure.

Mycoplasma hominis in women with bacterial vaginosis.

An association between M. hominis and bacterial vaginosis (BV) was looked for in total 205 women characterized as having BV. Vaginal specimens from these patients were studied for the presence of amines, polymorphonuclear leukocytes, clue cells, and lactobacilli, and were also cultured to isolate Gardnerella vaginalis, M. hominis, Trichomonas vaginalis, Candida albicans and anaerobes. G. vaginalis was found to be the most common isolate from 132 cases (64.3%). M. hominis was isolated from 90 cases (43.9%). 62 per cent of M. hominis isolates were associated with G. vaginalis. 100 age matched control group revealed low prevalence of G. vaginalis and M. hominis whereas the difference in isolation rate of anaerobes was not significant. Anaerobes were found in association with M. hominis in 40 per cent cases. The treatment of these patients was decided after knowing the etiological agent.

Detection of serum antitrichomonal antibodies in urogenital trichomoniasis by immunofluorescence.

Trichomonas vaginalis is a frequently encountered genital pathogen in both males and females. In females, vaginitis due to this parasite is one of the most common manifestation. The indirect fluorescent technique (IFA) test was carried out to detect antitrichomonal antibodies in 370 female patients using whole cell antigen. Seventy one (19.18%) gave positive reaction for either of the class IgG, IgM and IgA antibodies. The level of the IgG class antibodies was found to be higher i.e. 58 (81.69%) than IgM 11 (15.27%) antibodies, which may be suggestive of past infection or a prolonged manifestation by the organisms.

A comparison of three media for isolation of Nocardia species from clinical specimens.

The study was carried out to compare the efficacy of three media namely Modified Thayer Martin medium, McClung's carbon free broth with paraffin bait and paraffin agar in isolating Nocardia species from clinical specimens. Two hundred and seventy six clinical specimens from 245 cases were studied which included cases of bronchopulmonary and systemic infections and cases of mycetoma. Paraffin agar was found to be an inexpensive and selective medium for isolation of Nocardia species when compared with Modified Thayer Martin medium and paraffin bait techniques.

Acute Campylobacter jejuni enteritis in 385 hospitalised patients.

Twenty healthy controls and 385 adult patients suffering from acute enteritis or gastroenteritis were enrolled for the study of Campylobacter Jejuni infection over a period of 2 years. Thirty five stool samples showed C jejuni on stool culture. The isolation rates were at peak in the monsoon season and from watery and bloody stool specimens. Pure C jejuni culture was obtained in 18 of 35 samples; the other 17 samples showed polymicrobial infection or infestation. Nine of 35 patients were treated with erythromycin 1 g in divided doses for 7 days. Repeat stool cultures did not grow C jejuni. There was no resistance to erythromycin therapy. C jejuni are fastidious organisms and require special medium and microaerophilic environment for culture.