Clonal similarities and sequence-type diversity of invasive and carriage Streptococcus pneumoniae in India among children under 5 Years

Background: Pneumococcal pneumonia is one of the major causes of mortality in children less than 5 years in Asia, especially in India. Available PCVs have less serotype coverage in India compared to western countries. Moreover, the baseline pneumococcal serotype and sequence type data is limited and available data doesn't represent the entire India. With this background we aimed to characterize invasive and carriage isolates of S. pneumoniae from a tertiary care hospital in South India. Materials and Methods: A total of 221 S. pneumoniae isolates, invasive (n=138) and carriage (n=83) between the time period of 2012-2018 were included. Isolates was identified and confirmed using standard laboratory protocols. Serotyping was performed by Customized sequential multiplex PCR and MLST as described in www.pubmlst.org. Results: The major serotypes were 19F, 6B, 14, 6A and 19A and the sequence types (ST) were ST63, 236 and 230. Predominant STs in invasive was ST 63 whereas in carriage were ST4894 and 1701. High level ST diversity in carriage was observed. Majority of the STs were SLVs or DLVs of previously reported STs or PMEN clones. Phylogenetic analyses of the STs revealed gradual expansion of three PMEN CCs CC320, 63 and 230. Conclusion: The vaccine serotypes were the predominant ones found to be associated with IPD, PMEN clones, new STs and antimicrobial resistance. Accordingly, PCV13 is expected to provide invasive serotype coverage of 75% in Indian children less than 5 years. This study provides baseline serotype and sequence type data prior to the introduction of PCV in South India.

Clinical relevance of cagA and vacA and association with mucosal findings in Helicobacter pylori-infected individuals from Chennai, South India

Helicobacter pylori is associated with a spectrum of severe gastrointestinal conditions. In this study, an attempt was made to correlate endoscopic mucosal patterns with H. pylori infection and examine the pathogenic potential of the strains. Among the 147 dyspeptic individuals studied, 42.2% were H. pylori infected. Association of H. pylori with type 3 and 4 mucosal patterns (P = 0.001) and intestinal metaplasia (P = 0.012) was seen. vacA was associated with histological (P = 0.014) and endoscopy findings (P = 0.009). Association of mucosal patterns with H. pylori infection could be useful for clinicians to decide on the need for eradication therapy.

Diversity of arbuscular mycorrhizal fungi in irrigated and non-irrigated fields of southern Karnataka, India.

The two different agro-ecosystems were selected to study the spore density, species abundance, and diversity of arbuscular mycorrhizal fungi (AMF) in irrigated (Mandya district) and non-irrigated (Hassan district) agricultural fields in southern Karnataka region, India. A total of 22 AMF species were recorded during the study. Out of which 13 sp. were of Glomus, 4 sp. of Acaulospora, 1 sp. of Cetraspora, 1 sp. of Dentiscutata and 3 sp. of Gigaspora. The difference in species richness of AMF species in irrigated fields ranged from 5-12 sp. as compared to non-irrigated fields (5-11 sp.) and the difference may be attributed to the nutritional status of the soil. We also assumed that lower AMF colonization and abundance would be affected by water stress. Highest spore number and percent colonization of AM fungi were recorded in irrigated sites, showing 356-748 spore density and 70-92 % colonization. Whereas, in non-irrigated sites, 174-341 spore density and 40-72 % colonization was recorded. Different agro-climatic conditions like irrigation, soil pH, soil organic carbon, phosphorous correlated with the abundance and colonization of AM fungi.

Comparison of double disc and three dimensional methods to screen for ESBL producers in a tertiary care hospital.

Extended spectrum beta lactamases (ESBLs) continue to be a major problem in clinical setups world over, conferring resistance to the expanded spectrum cephalosporins. An attempt was made to study ESBL production among Enterobacteriaceae members from a tertiary care center in Chennai. A total of seventy randomly collected isolates of the family Enterobacteriaceae from a tertiary care center was studied for their susceptibility patterns to various antibiotics and detection of ESBL producers by double disc synergy (DDS) test and three dimensional test (TDT). Eighty percent of the isolates were multidrug resistant (MDR) and 20% were ESBL producers. TDT detected 85.7% whereas only 14.2% were detected by DDS. In the present study, a large number of isolates were found to be MDR and ESBL producers. TDTs were found to be better than DDS in the detection of ESBLs. Continued monitoring of drug resistance is necessary in clinical settings for proper disease management.

Rapid discrimination between strains of beta haemolytic streptococci by intact cell mass spectrometry.

BACKGROUND & OBJECTIVES: Beta haemolytic streptococci belonging to Lancefield group A, B, C and G cause a wide spectrum of clinical diseases. Hence there is a need for rapid and accurate typing of these strains. The present study was undertaken to evaluate the use of intact cell matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for rapid discrimination between strains of beta haemolytic streptococci. METHODS: Colonies of beta haemolytic streptococci were emulsified with chemical matrix on the sample slide, dried and analyzed by MALDI-TOF-MS. RESULTS: The reproducibility of results for all groups of beta haemolytic streptococci was good and spectra obtained for Lancefield group A, C and G streptococci showed discrimination between the groups on visual comparison. A finer difference in spectrum was observed among group A streptococci isolated from different locations at different periods of time. INTERPRETATION & CONCLUSION: MALDI-TOF-MS may be a potential tool in discriminating between strains of beta haemolytic streptococci, and also in the characterisation of untypable strains of group A streptococci.

Group A streptococcal infections of the pharynx in a rural population in south India.

BACKGROUND & OBJECTIVES: There has been a resurgence in the incidence of rheumatic heart disease all over the world and hence surveillance and strain characterization are important. The aim of this study was to screen children in a rural community in south India for throat carriage of group A streptococci and to clinically assess them for signs of rheumatic heart disease. METHODS: Throat swabs were collected from children (5-14 yr) in the village of Orathur, Tamil Nadu and cultured on tryptose blood agar plates. Beta haemolytic streptococci were serogrouped using Streptex kit and biotyped based on their ability to ferment carbohydrates and production of beta-glucuronidase enzyme. Blood samples were also collected and antibodies to streptolysin O demonstrated by latex agglutination tests. All the children were examined by a paediatrician; ECG and echocardiography were performed to assess cardiac function. RESULTS: Eighty of the 310 children included in the study had symptoms of acute respiratory infections; 16 of them grew beta haemolytic streptococci of which 8 belonged to group A (10%). Biotype 4 was most common. Antistreptolysin O (ASO) test did not correlate with culture results. Two of 310 children had rheumatic heart disease but both were culture negative. INTERPRETATION & CONCLUSION: Pharyngeal carriage of group A streptococci was common in this population. The prevalence of rheumatic heart disease was 0.6 per cent. The study emphasizes the need for active surveillance and characterization of GAS isolates.

Occurrence of group C Streptococci in children in a South Indian village.

Throat swabs were collected from 310 children aged 5-14 years attending a rural health camp at Orathur near Chennai. Group C Streptococci were isolated from 13/310 (4.19%) cases. Seven out of 13 patients had symptoms of respiratory tract infection. Biochemical characterization of the isolates was done by hemolytic characteristics, Voges-Proskauer test, fermentation of trehalose and sorbitol and hydrolysis of 4-methylumbelliferyl-D-â-glucuronide. Four out of 13 strains were identified as S. equisimilis.