For nearly a century, there were no alternatives to the tuberculin skin test (TST) for diagnosing latent tuberculosis infection. Because of advances in immunology and genomics, for the first time, an alternative has emerged in the form of T cell based interferon-g (IFN-g) assays, a new generation of in vitro tests of cellular immunity. These assays measure cell mediated immune response by quantifying IFN-g released by T cells in response to stimulation by Mycobacterium tuberculosis antigens. Although early versions of IFN-g assays used purified protein derivative (PPD) as the stimulating antigen, newer versions use antigens that are significantly more specific to M. tuberculosis. These specific antigens include ESAT-6 and CFP-10. These proteins, encoded by genes located within the region of difference 1 (RD1) segment of the M. tuberculosis genome, are more specific to M. tuberculosis than PPD because they are not shared with any BCG substrains or several nontuberculous mycobacterial species. A review of current evidence on the performance of IFN-g assays and TST suggests that both the TST and IFN-g assays have advantages and limitations, and both tests appear to be useful at this time. The emergence of IFN-g assays is a much anticipated, welcome development that has, for the first time, increased the choice of tests available for diagnosing latent tuberculosis infection. Because both tests have their strengths and limitations, the decision to select one over the other will depend on the population, the goal of testing, and the resources available. To fully evaluate the utility of IFN-g assays in high burden countries such as India, long-term cohort studies are needed to determine the association between positive IFN-g results and the subsequent risk of active disease.

The nature of reporting of a microbiology laboratory depends upon the quality of the culture media used. Quality of media directly affects the observations and inferences drawn from the cultural characteristics of microorganisms. Checking of different parameters of media such as growth supporting characteristics, physical characteristics, gel strength and batch contamination can help to assess their quality. There are different methods to check all these parameters systematically. The meticulous performance of quality control of culture media can assure precision in reporting.

National Institute of Communicable Diseases (NICD) has been engaged in rubella testing for serodiagnosis of the infection and screening for immunity status. The compiled and evaluated data of the work done on rubella testing for the past fifteen years has been presented here to show the trend and changing scenario of the disease in Delhi. Blood samples were from 7424 patients referred to NICD, Delhi for serodiagnosis of congenital Rubella s yndrome (CRS) in malformed babies, in utero rubella infection in women and immunity status of pregnant women and women with bad obstetric history. They were tested for rubella IgG and/or rubella IgM antibodies using commercially available reagents and kits. The data from the 15 years of testing was then compiled and evaluated. From the available data it was seen that immunity status against rubella in childbearing age group of women increased steadily from 49% in 1988 to 87% in 2002. Reported cases of CRS at NICD are also on the decline over the time period. There is periodic indication of high incidence of rubella in the year 1988; 1991and 1998 as the reported cases of acute rubella infection in childbearing age group is high during these years.

Purpose : To assess the changing trends in the antibiotic susceptibility of Pseudomonas spp . isolated from bacterial keratitis over a nine year period with special emphasis on fluoroquinolone susceptibilities. Methods : All corneal scraping cultures positive for Pseudomonas spp. (n=585) isolated from patients with bacterial keratitis at the Aravind Eye Hospital, Madurai from1995-2003 were evaluated. Cultures were performed in liquid and solid media and susceptibility testing was done against amikacin, gentamicin, tobramycin, ciprofloxacin and ofloxacin by Kirby-Bauer disc diffusion method. Results: The susceptibility of Pseudomonas spp. was over 90% from 1995-1998 to ciprofloxacin which decreased to 83% from 1999-2003. The total number of isolates resistant to ciprofloxacin was 51(9.4%). No statistically significant increase in the number of isolates resistant to ciprofloxacin was noted. Ofloxacin showed 54% susceptibility from 1995-1998 but increased to 64% from 1999-2003. Analysis of in vitro activity of amikacin reveals that there was 43% sensitivity from 1995-1998 but later it increased to 76% from 1999-2003. In case of gentamicin, the sensitivity decreased marginally from 80% to 70% through the years. Tobramycin showed 45% sensitivity from 1995-1998 but increased to 75% from 1999-2003. Conclusions : The fluoroquinolones remain a good choice in the treatment of ocular infections, with high susceptibility of Pseudomonas spp. Among the aminoglycosides, gentamicin was found to be highly effective against Pseudomonas corneal ulcers when compared to amikacin and tobramycin. The results show a need for continuous monitoring of bacterial resistance trends.

Purpose: This is a retrospective analysis of the isolation rates of nontuberculous mycobacteria (NTM) from various clinical specimens and their antimicrobial susceptibility patterns. Methods: All NTM isolated between 1999 and 2004 at Christian Medical College, Vellore, South India, were identified with various biochemical tests. Antimicrobial susceptibility test for all NTM was performed by standard methods. Results : A total of 32,084 specimens were received for culture, of which 4473 (13.9%) grew acid fast bacilli (AFB). Four thousand three hundred (96.1%) of the AFB were M. tuberculosis while 173 (3.9%) were NTM. Of the 173 NTM, 115 (66.5%) were identified to the species level. Pus, biopsy specimens and sputum specimens yielded most of the NTM of which M. chelonae (46%) and M. fortuitum (41%) accounted for majority of them. M. chelonae and M. fortuitum , showed highest susceptibility to amikacin (99.2%). NTM were repeatedly isolated from seven sputum specimens, 15 biopsy and pus specimens, two CSF and two blood cultures. Six were isolated from patients with AIDS and five from post transplant patients. Conclusions: The isolation of NTM from various clinical specimens is reported in this study to highlight the associated diseases and therapeutic options in these infections.

Plasmodium falciparum infections are frequently fatal if untreated and hence need to be diagnosed and treated early. Malaria diagnosis, with conventional Giemsa staining as a gold standard, has had several limitations. New rapid and accurate methods are needed for diagnosis. In this study, polymerase chain reaction (PCR) analysis specific for diagnosis of P. falciparum was evaluated. For the study, blood samples were collected from 310 patients suspected of having malaria. PCR analysis for P. falciparum from venous blood and at the same time Giemsa staining of thick and thin blood smears was done. A total of 160 (51.6 %) samples were positive for malarial parasite of which 63 (39.4 %) were positive for P. falciparum by Giemsa staining while 61 (38.1 %) were positive for P. falciparum by PCR analysis. Giemsa staining was time consuming, laborious and may give poor results in cases with low parasitaemia. The PCR analysis for P. falciparum was able to detect 3 cases of low parasitaemia missed initially on Giemsa staining, was 96.8 % sensitive, 100% specific but was very costly, needed a lot of practice and standardization and was time consuming. PCR analysis can be used to supplement the conventional Giemsa staining for reliable diagnosis of falciparum malaria especially in cases with low parasitaemia.

The resurgence of Mycobacterium tuberculosis in association with HIV infection has focussed much attention in the rapid diagnosis of high risk cases. Infection with HIV is known to alter the presentation of pulmonary tuberculosis. The present study was under taken to compare the efficacy of fluorochrome stain (Fl) with conventional Ziehl Neelsen (ZN) stain in the diagnosis of pulmonary tuberculosis. Two hundred cases of pulmonary tuberculosis were included in the study. Sputum smears were screened for acid fast bacilli (AFB) by ZN and Fl methods and blood samples were screened for HIV. Sputum positive cases detected by Fl stain were higher in number (69%) when compared to ZN stain (50%). Of the total cases studied 15.5% were HIV seropositive. Conclusions : Fluorochrome staining was found to be more efficient (45%) when compared to ZN staining (29%) in detecting cases associated with HIV seropositivity, especially paucibacillary cases.

A sunflower ( Helianthus annuus ) seed husk agar medium has been developed and evaluated for differentiation of Candida dubliniensis from Candida albicans on the basis of colony morphology and chlamydospore production. All C. dubliniensis isolates (n=40) produced rough colonies with hyphal fringes and abundant chlamydospores whereas 101 of 105 (96.2%) C. albicans isolates produced smooth colonies with no evidence of chlamydospore production. Since this medium is free from oil droplets, chlamydospores can be examined with greater clarity by Dalmau plate technique. This medium provides a simple and cost-effective tool for the presumptive differentiation of C. dubliniensis from C. albicans and is particularly suited for clinical microbiology laboratories where biochemical or molecular methods for the differentiation of these two species are not available.

The objective of this study was to find the prevalence of Staphylococcus spp. carriage among hospital personnel and hospital environment and their antibiogram with special emphasis on methicillin resistance. A total of 205 samples from hospital personnel and environment were collected from casualty, oncology and multidisciplinary cardiac unit ward of Kasturba Medical College Hospital, Manipal. Samples were collected using sterile cotton wool swabs and inoculated into brain heart infusion broth. Subcultures were done onto blood agar and MacConkey's agar. Isolates were identified by standard methods up to species level. Antimicrobial susceptibility test was performed according to standardized disc diffusion Kirby-Bauer method. Each of the isolates was screened for methicillin resistance using oxacillin disc on Mueller Hinton agar plate followed by MIC for methicillin and cefoxitin susceptibility test by disc diffusion method. Sixty five out of 205 strains (31.7%) were Staphylococcus spp. and all of them were coagulase negative. Most of the strains belonged to S.epidermidis 49.23%(32/65) followed by S. saprophyticus 26.15%(17/65). Maximum isolates of S.epidermidis were from anterior nares 28.12%(9/32 strains of S.epidermidis ). Highest number of methicillin resistant coagulase negative strains (3/9, 33.33%) were isolated from stethoscope of multidisciplinary cardiac unit ward followed by carriers in the anterior nares (2/9, 22.22%). Methicillin resistant coagulase negative staphylococci are prevalent in anterior nares of hospital personnel and in the hospital environment thereby providing a definite source for hospital acquired infection. All isolates were sensitive to vancomycin, ciprofloxacin and amikacin.

Resistance to carbapenems is commonly seen in nonfermenting gram negative bacilli (NFGNB). We document herein the prevalence of carbapenem resistance in NFGNB isolated from patients with respiratory tract infections in the intensive care units (ICUs). A total of 460 NFGNB were isolated from 606 endotracheal aspirate specimens during January through December 2003, of which 56 (12.2%) were found to be resistant to imipenem and meropenem. Of these, 24 (42.8%) were Pseudomonas aeruginosa , 8 (14.2%) were Acinetobacter spp. and 24 (42.8%) were other NFGNB. Stringent protocols such as antibiotic policies and resistance surveillance programs are mandatory to curb these bacteria in ICU settings.

Opportunistic infections by Mycobacterium avium intracellulare complex in HIV infected patients, though common in adults, are rarely seen in infants. We herewith report an interesting case of an eight month old infant presenting with isolated axillary lymphadenitis, later on diagnosed to be tubercular lymphadenitis by Mycobacterium avium intracellulare and finally proved to be seropositive for HIV infection born to previously undetected HIV seropositive parents.

A case of invasive multiple paranasal sinus aspergillosis with bony involvement is reported. A young immunocompetent lady presented with bilateral nasal obstruction due to polyps. Radiologically and histopathologically a fungal cause was kept a possibility, and the diagnosis of Aspegillus fumigatus was established by demonstration of acute angle branching septate hyphae on direct wet mount and repeated isolation in culture. Patient responded favourably to surgical excision of polyps and oral itraconazole post operatively.

An unusual manifestation of breast fusariosis was encountered in a 55-year-old female diabetic patient. Two fine needle aspirates (FNA) from the abscess were done at three days interval and they showed hyaline, septate, branched, fungal hypahe in 10% potassium hydroxide mount. Fungal infection was confirmed by demonstrating the fungal hyphae in the midst of lymphocytes, macrophages and neutrophils in Leishman stained smears. Culture of both FNAs yielded a heavy and pure growth of Fusarium solani . The patient responded to oral ketoconazole 200 mg once daily for 3 weeks. The breast fusariosis reported here is presumably the first case in India.

Aspergillus infection of the central nervous system (CNS) is an uncommon disease. Most of the reported cases are of sinocranial spread and cases with contiguous spread to spinal cord from lung and other organs are uncommon. A case of pulmonary aspergillosis with extension to thoracic vertebrae forming a paraspinal mass resulting in neurological deficit due to Aspergillus flavus , is reported. The 43 year old patient did not have any obvious predisposing condition. He presented with loss of motor function and succumbed to the infection despite operative intervention and antifungal therapy. A brief update on CNS aspergillosis is presented along with detailed clinical, radiological and laboratory work up of the patient.