Variables affecting the performance of galactomannan assay in high-risk patients at a Tertiary Care Centre in India.

Background: Diagnosis of invasive aspergillosis (IA) in immunocompromised patients using galactomannan ELISA (GM-ELISA) has shown variable sensitivity and specificity. Objectives: To assess the diagnostic performance of GM-ELISA and analyze the effect of decreasing the cut off value, neutropenia, antifungals and piperacillin-tazobactam (PTZ). Prognostic value using 30 day all-cause mortality was also determined. Materials and Methods: Serum samples from 81 patients categorized into "proven," "probable," and "possible," categories based on revised EORTC/MSG definitions were tested by GM-ELISA. Results: Sensitivity of GM-ELISA in proven, probable and possible cases was 91.7%, 84.6% and 83.3% respectively. At an index cut-off value of 0.5 an increased sensitivity with minimal loss of specificity was observed. Use of antifungals demonstrated a decrease in sensitivity in proven and possible cases whereas it remained unaffected in probable category. Specificity increased from 75% to 100% with a positivity criterion of >2 consecutive samples. Although an increase in specificity was observed in patients not receiving PTZ, it was not statistically significant. Serial GM index values increased significantly in neutropenic patients and were associated with a poor prognosis. Conclusions: GM-ELISA may be a useful diagnostic and prognostic modality for the detection of IA in high risk patients.

Utility of GenoType MTBDRplus assay in rapid diagnosis of multidrug resistant tuberculosis at a tertiary care centre in India.

Purpose: Molecular methods which allow rapid detection of tuberculosis as well as drug resistance directly from clinical samples have become the most popular diagnostic methodology with the emergence of multidrug resistant tuberculosis. The aim of the present study was to evaluate the performance of a line probe assay, GenoType MTBDRplus for the rapid detection of Mycobacterium tuberculosis and mutations causing rifampicin and INH resistance directly in smear positive pulmonary specimens and also in M. tuberculosis isolates grown from various clinical specimens. Materials and Methods: The MTBDRplus assay was done directly on 37 smear positive pulmonary specimens and also on 69 M. tuberculosis isolates obtained by rapid automated culture using Bact/Alert 3D. The results were compared with phenotypic drug susceptibility testing (1% proportion method) using Bact/Alert 3D. Results: The sensitivity and specificity for detection of resistance to rifampicin was 100% and 97.3%, and to INH was 91.9% and 98.4%, respectively, in comparison with the phenotypic drug susceptibility testing. Conclusion : MTBDRplus assay had good sensitivity and specificity with turn around time of less than 48 hours. It may be a useful tool for rapid detection of multidrug resistant tuberculosis at a tertiary care centre.

High level ciprofloxacin resistance in Salmonella enterica isolated from blood.

PURPOSE: Over the last few years, resistance to ciprofloxacin in Salmonella enterica has become a global concern. The present study was undertaken to find out the susceptibility pattern of Salmonella enterica isolates in our hospital. METHODS: Blood cultures were done using BacT/ALERT 3D system. The antimicrobial susceptibility testing was carried out by the Kirby-Bauer disc diffusion method using CLSI breakpoints. Minimum inhibitory concentration was determined for ciprofloxacin-resistant strains using E-test and Vitek-1 automated system. RESULTS: A total of 25,953 samples of blood culture yielded 431 Salmonella enterica serotype Typhi and 198 serotype Paratyphi A isolates. Twenty-two isolates of serotype Typhi were resistant to ciprofloxacin, while two isolates of Typhi and two Paratyphi A were intermediately susceptible to ciprofloxacin. Ciprofloxacin resistance is 5.6% (24 isolates) among Salmonella enterica serotype Typhi. Ampicillin, chloramphenicol and co-trimoxazole resistance in Salmonella enterica serotype Typhi appears to have decreased to 14.9% (64/431) in comparison to the 27% (55/205) during 2003. All isolates were sensitive to ceftriaxone. CONCLUSIONS: Ciprofloxacin can no longer be considered as the drug of choice in treating Salmonella infections. While first-line antimicrobials may still have a role to play in the treatment of enteric fever, ceftriaxone remains the sole defence against ciprofloxacin-resistant Salmonella infections.

Nasopharyngeal carriage of Streptococcus pneumoniae.

OBJECTIVE: To determine nasopharyngeal carriage rate and prevalent serogroups/types (SGT) of S. pneumoniae in healthy children, assess their antimicrobial susceptibility and its implications over the heptavalent pneumococcal conjugate vaccine. METHODS: 200 healthy children aged between 3 months and 3 years attending Pediatric OPD at Sir Ganga Ram Hospital, New Delhi were studied. A nasopharyngeal swab was collected from each child which was processed to isolate Streptococcus pneumoniae. Serotyping was performed by the Quellung reaction. Antimicrobial susceptibility patterns were determined by disk diffusion and E test methods. RESULTS: S. pneumoniae carriage rate was 6.5%. Isolates belonged to serotypes 1, 6, 14 and 19, of which serotype 19 was the most common. None of the strains were totally resistant to penicillin though 2 (15.4%) were intermediately resistant. Overall, 84.6% of the isolates belonged to the strains covered by the heptavalent pneumococcal vaccine. CONCLUSION: The heptavalent conjugate vaccine covers most isolated strains, but since the number of strains is very small, it is suggested that there is need for further studies in different regions to assess the usefulness of this vaccine.

Cutaneous cryptococcosis.

We report a case of an apparently immunocompetent male, who presented with a painless nodule over the upper abdominal wall. He gave a history of exposure to pigeon droppings. Cryptococcus neoformans was isolated from the lesion and no underlying disorder could be detected. He improved on treatment with oral Fluoconazole.