Epstein-Barr Virus: An Infrequent Pathogen of Acute Undifferentiated Febrile Illness From a Tertiary Care Hospital in Southern India.

CONTEXT: Acute undifferentiated febrile illness (AUFI) is characterized by a sudden onset of raised body temperature and is a common cause of hospital admission though not recognized as a disease state by the World Health Organization. Epstein-Barr virus (EBV) is reported to account for a significant occurrence of AUFI cases. AIM: To know the role of EBV infection as a cause of acute undifferentiated febrile illness (AUFI). SETTINGS AND DESIGN: We have used the combination of EBV serological assays to establish the role of the Epstein-Barr virus as the cause of acute undifferentiated febrile illness. METHODS AND MATERIAL: A total of 721 suspected cases of acute undifferentiated febrile illness which were tested negative for other common causes of acute febrile illness were selected for the study. Serum samples collected from these cases were tested for the presence of the EBV viral capsid antigen (VCA) IgM antibody. All positive serum samples were tested for the presence of EBV Epstein-Barr nuclear antigen (EBNA) IgG. STATISTICAL ANALYSIS USED:  Statistical analysis was performed with the help of Microsoft Excel software (Microsoft Corporation, Redmond, USA).  Results: Out of 721 suspected AUFI cases tested for EBV VCA IgM antibodies, 117 samples were positive and 604 were negative. All these 117 samples were tested for EBV EBNA IgG antibodies in which 88 were positive and 29 were negative. In our study, we found that around 4% (positive for VCA IgM and negative for EBNA IgG) of AUFI cases can be attributed to primary acute EBV infection. CONCLUSIONS: EBV infection should be considered particularly in AUFI cases of less than five years of age even in those who do not meet the typical presentation of fever, lymphadenopathy and sore throat. Our study should help to raise awareness regarding the possibility of EBV infection particularly in AUFI cases. A high index of suspicion and timely diagnosis will definitely help clinicians to avoid a battery of investigations and misuse of antibiotics in cases of AUFI.

Prevalence and speciation of non-tuberculous mycobacteria among pulmonary and extrapulmonary tuberculosis suspects in South India.

BACKGROUND AND OBJECTIVES: Non tuberculous mycobacteria (NTM) is an emerging opportunistic pathogen increasing globally and indistinguishable from tuberculosis (TB), which remains a challenge particularly in developing countries. This study aimed to identify the prevalence and diversity of NTM among both pulmonary TB (PTB) and extrpulmonary TB (EPTB) clinical isolates from south India. METHODOLOGY: A total of 7633 specimens from TB suspects (PTB, n = 4327 and EPTB, n = 3306) were collected during the study period (July 2018-March 2020) in a tertiary care hospital. The study specimens were subjected to Ziehl Neelsen (ZN) staining and Auramine phenol (AP) staining followed by Lowenstein-Jensen (LJ) and mycobacteria growth indicator tube (MGIT) culture. The MPT64 immunochromatographic test (ICT) was performed among mycobacterial cultures and ICT negative isolates were subjected to Line Probe Assay (LPA). In addition, 53 (PTB, 48 and EPTB, 5) NTM MGIT positive cultures were collected from Intermediate Reference Laboratory (IRL), Puducherry and subjected to LPA for speciation. RESULTS: Of the 7633 TB suspects, 0.6% were diagnosed as NTM diseases and 5.5% with Mycobacterium tuberculosis (MTBC). NTM infection was observed among 0.7% (31/4327) of PTB and 0.4% (14/3306) of EPTB. MTBC was detected among 6.1% (264/4327) of PTB and 4.6% (153/3306) of EPTB. Among 98 NTM cultures, 80.6% of isolates were recovered from PTB and 19.4% from EPTB specimens. Among pulmonary specimens, Mycobacterium intracellulare (26.6%), Mycobacterium abscessus (17.7%) and Mycobacterium kansasii (12.7%) were the most frequently detected species, while Mycobacterium intracellulare (21.1%), Mycobacterium scrofulaceum (15.8%) and Mycobacterium fortuitum (10.5%) were common in extrapulmonary specimens. CONCLUSION: The frequency of NTM infection among TB suspects was low at a South Indian tertiary care hospital. The most predominant NTM species isolated from both pulmonary and extrapulmonary specimens was M. intracellulare.

Diagnostic performance of real time PCR and MALDI-TOF in the detection of nontuberculous mycobacteria from clinical isolates.

This study aimed to evaluate the performance of real-time PCR (qPCR) and MALDI-TOF for accurate and timely detection of nontuberculous mycobacterium (NTM) from clinical isolates. We collected fifty NTM suspected Mycobacteria Growth Indicator Tube (MGIT) cultures and analysed the diagnostic performance of qPCR and VITEK MS using Line Probe Assay (LPA) GenoType CM (Common Mycobacteria) as gold standard. The qPCR assays targeting 16S rRNA, ITS and IS6110 genes were developed for the identification of NTM and Mycobacterium tuberculosis complex (MTBC). LPA GenoType CM, a PCR technique targeting 23S rRNA gene, followed by reverse hybridization and line probe technology identified 90% of Mycobacterium species including M. fortuitum (16%,n = 8), M. intracellulare (10%,n = 5), M. gordonae (10%,n = 5), M. xenopi (4%,n = 2), M. scrofulaceum (4%,n = 2), Mycobacterium additional species (AS) (32%,n = 16) and MTBC (14%,n = 7), qPCR detected 80% of Mycobacterium species (NTM, 66% (n = 33) and MTBC, 14% (n = 7)) and MALDI-TOF, 52% (M. fortuitum (12%,n = 6), M. intracellulare (10%, n = 5), M. simiae (8%,n = 4), M. gordonae (8%,n = 4), and MTBC (14%,n = 7)). Sensitivity of qPCR and MALDI-TOF was 88.9% and 57.8%, respectively with 100% specificity. The combination of qPCR and MALDI-TOF remains an appropriate test for timely diagnosis of Mycobacterium species. This may eventually assist to detect the cases that may have been missed by phenotypic tests and enhance the NTM diagnosis capability to improve effective patient management.