Frequencies of regulatory subsets of CD4+ TH cells in peripheral blood in Mycobacterium Tuberculosis-Infected individuals and healthy contacts in a high-burden setting from Assam, Northeast India

Background: Mycobacterium tuberculosis (Mtb) adapts many strategies to persist and replicate inside human tissue. One such strategy is the manipulation of CD4+ TH cells for subset interconversion to regulatory subsets. The aim of the present study is to get an insight of dynamic changes of CD4+ TH cells to regulatory subsets, CD4+ CD25+ forkhead box P3 (Foxp3)+ T-cells and CD4+ CD25+ Foxp3+ programmed death molecule-1 (Foxp3+) T-cells, in peripheral blood in Mtb-infected individuals and healthy contacts in a high-burden setting from Assam, Northeast India. Materials and Methods: A case–control study was conducted in newly diagnosed active pulmonary tuberculosis (APTBs) patients and 2 sets of controls: (i) individuals infected with latent tuberculosis infection (LTBI) and (ii) healthy close tuberculosis healthy contacts (HCs). The frequencies of different subsets of CD4+ cells with regulatory markers were measured in peripheral blood in 3 groups of study participants. Results and Observations: Frequencies of CD4+ CD25+ Foxp3+ T-cells (1.84 ± 1.40 vs. 4.32 ± 1.82 vs. 11.30 ± 3.66), CD4+ CD25+ Foxp3+ PD1+ T-cells (0.37 ± 1.28 vs. 2.99 ± 3.69 vs. 14.54 ± 5.10) and ligand (PD-L1)-positive CD4+ TH cells (0.80 ± 0.45 vs. 2.28 ± 0.95 vs. 7.13 ± 2.02) were significantly increased from HCs to LTBIs to APTB patients, respectively (P < 0.0001). No significant changes in frequencies of total CD4+ cells were observed between APTBs (29.51 ± 11.93), LTBIs (29.23 ± 8.16) and HCs (28.16 ± 9.73) whereas the mean ratios of CD4+ to CD4+ CD25+ FoxP3+ were significantly decreased from 34.34 ± 47.56 in HCs to 7.96 ± 5.8 in LTBIs to 3.12 ± 2.58 in APTBs (P < 0.0001). Significant decrease in mean ratios of CD4+ CD25+ FoxP3+ to CD4+ CD25+ FoxP3+ PD1+ were also observed from 4.97 ± 1.09 in HCs to 1.44 ± 0.49 in LTBIs to 0.78 ± 0.72 in APTBs. Conclusion: CD4+ TH cells change dynamically to regulatory subsets depending on the status of infection and a shift of response towards excessive regulatory T-cells, and PD-1/PD-L1 production may help in the development of active infection in latently infected individuals. These immunological parameters may be used, as potential biomarkers to see the changing dynamics of Mtb infection.

Serotyping of dengue viruses circulating during 2014–2015 in Assam, India

Dengue has become endemic in India with outbreaks caused by all the four serotypes occurring almost every year. Dengue cases have been increasing alarmingly in Assam also. This study aimed to identify the dengue serotypes circulating in Assam. Clinically suspected dengue fever cases were included in the study. Viral RNA was extracted using QIAamp Viral RNA Mini Kit (Qiagen). Nested reverse transcriptase polymerase chain reaction was done for serotyping. The frequency of dengue was 25.23% with a peak during the period from September (22.56%) to October (26.22%). Two serotypes were detected, DEN-1 (72.7%) and DEN-2 (12.1%) and dual infection in 15.1%.

Molecular characterisation of virulent gene vacA in Helicobacter pylori clinical isolates from patients with gastroduodenal diseases in Assam, India

Background: Helicobacter pylori, the gastric bacterium, is widely known to be one of the most genetically diverse group of organisms whose pathogenesis as well as the diversity in infection outcome may be attributed to a variety of virulent genes. Aim: This study aimed to study the molecular profile of H. pylori vacA gene by determining the phylogenetic relatedness and genetic diversity of the strains isolated in this region with those of other geographical regions. Materials and Methods: A total of twenty H. pylori clinical strains were isolated from randomly selected 100 patients suffering from gastroduodenal diseases as well as endoscopically normal patients in a cross-sectional hospital-based setting from January 2016 to May 2017. VacA signal sequence and mid regions of H. pylori were amplified by polymerase chain reaction followed by DNA sequencing and phylogenetic analysis. Results: VacA s1m1 allelic variant was more prevalent in our study, regardless of the clinical outcomes. Phylogenetic analysis of VacA s1 strains revealed clustering of most of the strains. VacA m1 strains clustered with Bangladesh strains which is a country nearest to India. Conclusion: Prevalence of VacA s1m1 strains may account for high risk of transmission of this gastric pathogen and the overall risk of acquiring infection. Phylogenetic analysis results suggests the prevalence of high genetic diversity in our region. Our findings may aid in developing a better understanding of the genetic structure of H. pylori and the pathophysiology of associated diseases, thus facilitating the implementation of various treatment options.

Salmonella Weltevreden food poisoning in a tea garden of Assam: An outbreak investigation.

Background: Salmonella enterica serovar Weltevreden has been a rare cause of acute gastroenteritis occurring worldwide. Here, we report an outbreak of food poisoning in a tea garden. Objectives: To determine the aetiological agent and risk factors responsible for the outbreak and to take necessary steps for prevention of future outbreaks. Materials and Methods: Affected area was visited by a team of microbiologists for collecting stool samples/rectal swabs from affected patients. Samples were processed by culture followed by confirmation of the isolates biochemically, automated bacterial identification system, conventional serotyping and molecular typing. Water samples were also processed for detection of faecal contamination. Antimicrobial susceptibility testing was performed by Kirby–Bauer disc diffusion technique according to the Clinical Laboratory Standard Institute guidelines. Results: The isolates were confirmed as S. enterica subspecies enterica serovar Weltevreden. They were found sensitive to ampicillin, amoxycillin‑clavulanic acid, ciprofloxacin, ofloxacin, norfloxacin, cefotaxime, ceftriaxone, co‑trimoxazole and doxycycline. Water samples showed high‑level faecal contamination. Source of outbreak was found to be drinking water contaminated with dead livestock. House to house visit was made for early diagnosis and treatment of the cases, awareness campaigning and chlorination of drinking water. Conclusions: This report emphasises the geographical distribution of this organism in Assam. As S. Weltevreden is widely distributed in domestic animals, people should be made aware of immediate reporting of any unusual death among the livestock and their safe disposal which can significantly reduce the incidence of non‑typhoidal salmonellosis in the country.

Isolation of Shewanella algae from rectal swabs of patients with bloody diarrhoea.

Shewanella algae is an emerging bacteria rarely implicated as a human pathogen. It was infrequently recovered from clinical specimens probably because of inadequate processing of non-fermenting oxidase-positive gram-negative bacilli. We report here isolation of S. algae in pure culture and mixed with E. coli from two cases of acute gastroenteritis with bloody mucous containing diarrhea occurring at the same time. As this organism is not a normal flora of the gut, the possible source of infection may be fish contaminated with the organism. Whether this bacterium can be considered an enteric pathogen needs to be evaluated. The cases were clinically diagnosed as acute bacillary dysentery. The bacterium was identified by 16S r-RNA gene sequence analysis.

Sexually transmitted diseases in Assam: An experience in a tertiary care referral hospital.

Background: Sexually transmitted diseases (STDs) including AIDS are becoming a major public health problem in developing countries worldwide. Aims: All the adult patients attending VCTC and STD clinics of Assam Medical College between May 2002 and December 2005 were enrolled in the study. Methods: Records of patients with high-risk sexual behavior and presence of STD on clinical examination were recorded in a predesigned proforma. Results: Of 479 individuals, 186 (38.8%) had evidence of STD and 70 were positive for HIV. Most (64%) were in the age group of 15 to 30 years. Candidiasis (vulvovaginal candidiasis in women and candidal balanitis/balanoposthitis in men) was the most common finding on clinical examination (21.5%) followed by syphilis (17.2%), genital warts (15%), herpes genitalis (11.3%), non-gonococcal urethritis (10.8%), and gonococcal urethritis (7%). Conclusion: High percentage of unmarried people (>45%) reporting with STD, which points to potential danger of HIV transmission in the region.