Experience of Indian association of medical microbiology external quality assurance scheme centre, New Delhi: Challenges and quality assessment of clinical microbiology laboratories

Introduction: EQAS program at New Delhi under IAMM was started in January 2014 across North and North east regions of India with 217 participants, which grew up to 540 by 2018. Materials and Methods: In 2014, 4 analytes per year were sent for 3 exercises, i.e. smear culture and serology. 2018 onwards PT analytes were increased from 4 to 12 and comparative performance of techniques analysed. Results: Out of the 22 smears sent for gram staining, ZN staining, Kinyoun staining and Albert staining, completely correct results ranged between 29.55% - 79.9%, 94.3% - 99.2%, 35.5% & 93.8%, respectively. Correct results for culture isolate identification & susceptibility testing and serology exercises varied between 70 & 92.4% and 73.1 & 98.59%, respectively. In the year 2018, 470 responses were received for bacterial culture identification & antibiotic susceptibility testing out of which manual and automated systems were used by 54% & 46% and 52.5% & 47.5% participants, respectively. Techniques used in BBV assays for HBsAg, HCV & HIV found all methods like ELISA, ELFA, CLIA and Card Test performing similarly. The major challenges in running the EQA program included requirement of large amount of specimens for PT item preparation, stability in hot and humid conditions and timely delivery of PT challenges in remote parts of the country. Conclusion: A large number of the participating laboratories (77%) had an overall score of >80% for all exercises, demonstrating acceptable baseline performance of EQAS registered laboratories. However, continued EQAS participation could further improve the quality of results.

Comparative evaluation of two rapid Salmonella‑IgM tests and blood culture in the diagnosis of enteric fever.

Purpose: Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella‑IgM tests (Typhidot‑IgM and Enteroscreen‑IgM) as compared to blood culture in rapid and early diagnosis of enteric fever. Materials and Methods: A total of 2,699 patients’ serum samples were tested by Rapid Salmonella‑IgM tests and blood culture. Patients were divided into two groups. Test group—patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non‑enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi‑ A. In addition to this we have also evaluated the significance of positive Salmonella‑IgM tests among blood culture‑negative cases. Results: The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot‑IgM test and Enteroscreen‑IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot‑IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen‑IgM. Among blood culture‑negative patients, Rapid Salmonella‑IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella‑IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi‑ A also. Thirty‑eight patients who were blood culture‑positive for S. Paratyphi‑ A were also positive by Rapid Salmonella‑IgM tests. Conclusion: Rapid Salmonella‑IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.

A ten year analysis of multi-drug resistant blood stream infections caused by Escherichia coli & Klebsiella pneumoniae in a tertiary care hospital.

Background & objectives: Extensive use of antibiotics has added to the escalation of antibiotic resistance. This study was undertaken to evaluate the association, if any between antibiotic use and resistance in a hospital setting, and also detect the predominant mechanism of antibiotic resistance in Escherichia coli and Klebsiella pneumoniae over a period of 10 years. Methods: In a retrospective study of 10 years, a total of 77,618 blood culture samples from 2000 to 2009 from indoor patients were screened and those yielding E. coli and K. pneumoniae were included in the study. Antibiotic susceptibility records as well as the percentage of ESBL producers were noted. A total of 423 isolates of 2009 were also screened for AmpC and carbapenemase production. Antibiotic consumption data of 10 years were analysed. Results: ESBL producing E. coli increased from 40 per cent in 2002 to 61 per cent in 2009, similarly there was a significant (P<0.05) rise in resistance to cefotaxime (75 to 97%), piperacillin-tazobactum (55- 84%) and carbapenem (2.4-52%) in K. pneumoniae. A significant (P<0.05) association was observed between resistance and consumption of carbapenem and piperacillin and tazobactum consumption in K. pneumonia. Interpretation & conclusions: Our study demonstrated a rise in consumption and resistance to broad spectrum antimicrobial agents and also established an association between consumption and resistance to these antibiotics. Over a period of 10 years, the emergence of pan-resistance in K. pneumoniae could be due to the production of carbapenemases whereas ESBL production was the common mechanism of resistance in E. coli. This study warrants a directed effort towards continued surveillance and antibiotic stewardship to minimize selection pressure and spread.

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.

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.

Mixed salmonella infection - A case report.

Mixed infection with multiple Salmonella serotypes in the same patient is an unusual finding. We present a case of enteric fever in which the blood culture was sterile and Widal test was negative. The culture of the bone marrow yielded Salmonella typhi and Salmonella paratyphi A.