RESUMO
Background & objectives: Infections caused by vancomycin-resistant Enterococci are difficult to treat given the limited therapeutic alternatives. Different gene clusters are known to confer vancomycin resistance. vanA and vanB genes are transferable and are clinically relevant. This cross-sectional study aimed to identify the vancomycin-resistant genotypes in the strains causing urinary tract infection and also to test the in vitro efficacy of linezolid and pristinamycin against the vancomycin-resistant isolates. Methods: Antimicrobial resistance profile of 118 enterococcal isolates was evaluated. Minimum inhibitory concentration of vancomycin, teicoplanin and high-level gentamicin (HLG) was determined by micro broth dilution. The vancomycin-resistant isolates were tested against linezolid and pristinamycin by micro-broth dilution and E strip method. The presence of vancomycin-resistant genes was detected by multiplex polymerase chain reaction and was sequenced and analyzed. Results: Most commonly isolated species were Enterococcus faecalis (76.9%) and Enterococcus faecium (16.9%). It was found that 43 per cent of the isolates were resistant to HLG and 16.9 per cent to vancomycin. Higher resistance was seen against fluoroquinolones, erythromycin, tetracycline and ?-lactam drugs. However, 5.08 per cent strains were resistant to tigecycline. All vancomycin-resistant strains were sensitive to pristinamycin and one was resistant to linezolid. vanA and vanB gene were found in 15 and five isolates, respectively. The gene sequences were submitted to NCBI gene bank and accession numbers were obtained. Interpretation & conclusions: The present study showed prevalence of vanA and vanB genes carrying Enterococcus in a tertiary care centre in north India. The emergence of resistance against drugs such as tigecycline and linezolid is a topic of concern as it will be a therapeutic challenge for physicians.
RESUMO
Annual deaths in infants and young children due to rotavirus (RV) infection are around 100,000 in India and about 600,000 globally. Development of a vaccine for this disease is a high priority. The protective mechanisms for RV diarrhea in human are not fully understood, but it is known that children develop natural immunity against RV. Early exposure to RV results in most severe episode of diarrhea and subsequent infections are milder or asymptomatic. Of the immune responses measured during natural infection, RV-specific antibodies have been well documented, whereas data on cellular immunity in humans are sparse. It is generally thought that two outer capsid proteins VP4 and VP7 play a critical role in protective immunity by stimulating production of neutralizing antibodies. While serotype- specific protection mediated by antibodies directed against the outer capsid proteins may be a mechanism of protection, such a correlate for protection has been difficult to demonstrate in humans during clinical trials. Increasing evidences suggest that viral proteins that lack a capacity of eliciting neutralizing antibody response also induce protective immunity. Limited efforts have focused on the role of non-structural proteins in protective immunity. This review describes current understanding of antibody responses in children with focus on responses specific to viral antigens with their possible role in protective immunity. We have also briefly reviewed the responses elicited to non-antibody effectors during RV infection in human subjects.