Shigella spp. and Escherichia coli are closely related; both belong to the family Enterobacteriaceae. Phenotypically, Shigella spp. and E. coli share many common characteristics, yet they have separate entities in epidemiology and clinical disease, which poses a diagnostic challenge. We collated information for the best possible approach to differentiate clinically relevant E. coli from Shigella spp. We found that a molecular approach is required for confirmation. High discriminatory potential is seen with whole genome sequencing analysed for k-mers and single nucleotide polymorphism. Among these, identification using single nucleotide polymorphism is easy to perform and analyse, and it thus appears more promising. Among the nonmolecular methods, matrix-assisted desorption ionization-time of flight mass spectrometry may be applicable when data analysis is assisted with advanced analytic tools.

Modeling of the transmission dynamics of typhoid allows for an evaluation of the potential direct and indirect effects of vaccination; however, relevant typhoid models rooted in data have rarely been deployed. We developed a parsimonious age-structured model describing the natural history and immunity to typhoid infection. The model was fit to data on culture-confirmed cases of typhoid fever presenting to Christian Medical College hospital in Vellore, India from 2000–2012. The model was then used to evaluate the potential impact of school-based vaccination strategies using live oral, Vi-polysaccharide, and Vi-conjugate vaccines. The model was able to reproduce the incidence and age distribution of typhoid cases in Vellore. The basic reproductive number (R₀) of typhoid was estimated to be 2.8 in this setting. Vaccination was predicted to confer substantial indirect protection leading to a decrease in the incidence of typhoid in the short term, but (intuitively) typhoid incidence was predicted to rebound 5–15 years following a one-time campaign. We found that model predictions for the overall and indirect effects of vaccination depend strongly on the role of chronic carriers in transmission. Carrier transmissibility was tentatively estimated to be low, consistent with recent studies, but was identified as a pivotal area for future research. It is unlikely that typhoid can be eliminated from endemic settings through vaccination alone. We developed a mathematical model for the transmission dynamics of typhoid in order to evaluate the potential direct and indirect (i.e. herd immunity) effects of vaccination. The model was fit to data from Vellore, India and validated against the results of cluster randomized vaccine trials. We evaluated a variety of school-based vaccination strategies and found that typhoid vaccination is expected to lead to short-term indirect protection and a decrease in typhoid incidence, but vaccination alone is unlikely to lead to elimination. The level of indirect protection was found to depend on assumptions about the role of chronic carriers, identifying an important area for future research.

Acinetobacter baumannii is a nosocomial pathogen involved in a variety of infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteremia. The severity and the type of infections depend on the genetic and phenotypic variations of the strains. In this study we compared the extent of biofilm formation and motility displayed by sixty multidrug resistant A. baumannii clinical strains isolated from blood and sputum samples from patients from Southern India. Our results showed that isolates from the sputum samples formed significantly more robust biofilm compared to the blood isolates. On the other hand, we observed that the blood isolates were more motile than the sputum isolates. To our knowledge this is the first study that systematically evaluated the correlation between these two phenotypic traits and the nature of the isolates.

Acinetobacter species have emerged as one of the most clinically important pathogens. The phenotypic techniques which are currently available are insufficient in accurately identifying and differen... Lay abstract Acinetobacter species are considered to be one of the most important pathogens and associated with increased mortality. The species within the Acinetobacter calcoaceticus–Acinetobacter...

Increased incidence of multidrug resistant (MDR) Gram negative infection has resulted in high rates of morbidity and mortality. Klebsiella pneumoniae is one of the commonest MDR pathogens causing bacteraemia with limited therapeutic options such as colistin and tigecycline. Present study focused on molecular characterisation of MDR K. pneumoniae from bloodstream infection and their clinical outcome. A total of 115 K. pneumoniae from January 2015 to September 2016 were included in the study which comprised of phenotypically identified ESBL and carbapenem resistant (CR) isolates. Multiplex PCR was performed for detection of resistance genes encoding β-lactam resistance. This includes bla_SHV, bla_TEM, bla_VEB, bla_PER, bla_CTX-M, bla_DHA, bla_CIT, bla_FOX, bla_ACC, bla_ACT, bla_NDM, bla_OXA48-like, bla_VIM and bla_KPC. Co-expression of bla_SHV, bla_TEM and bla_CTX-M was predominant with 64% (74/115) prevalence. CTX-M-1 was the variant produced by all the isolates producing CTX-M. AmpC was uncommon, seen in 5% of the isolates (6/115). Among the carbapenemases co-expression of bla_NDM and bla_OXA48-like was observed in 28% (32/115) and bla_NDM in 19% (22/115) and bla_OXA48-like in 13% (15/115). bla_KPC was absent. Overall mortality was observed to be 57% (64/113) and mortality among CR K. pneumoniae (Kp) was 68% (50/73). The antibiotics that were administered for treatment of CRKp were colistin in 90% (66/73) and tigecycline in 7% (5/73) and in 99% combined with meropenem (72/73). Prevalence of community acquired and nosocomial infections were 5% (4/73) and 95% (69/73) respectively among CRKp. Minocycline and meropenem susceptibilities were comparable and hence minocycline can be a carbapenem sparing agent. The resistance to β-lactam antibiotics is steadily increasing and are plasmid mediated, their containment in healthcare setting is a challenge.