Vikas Gautam

A 16-year study of HIV seroprevalence and HIV-related diseases in a teaching tertiary care hospital in India.

A total of 183,912 persons were screened from September 1986 to May 2002 in and around Haryana, out of whom 1178 were reactive (0.64%) for anti-HIV antibodies. The overall incidence of HIV-1 in the seropositive patients was 98.5%, HIV-2 alone was 0.8% and 0.7% had a mixed infection with both HIV-1 and 2. High seropositivity (22.8%) was observed among the relatives of these HIV-positive individuals. The heterosexual route (78%) remained the predominant mode of transmission. Among the jail inmates only one individual out of 1306 (1986 to 1993) was found to be positive. Tuberculosis (46.7%) was the most common opportunistic infection in these seropositive patients. Significant titres of Venereal Disease Research Laboratory tests were observed in 8.8% seropositive patients, 7.9% were positive for hepatitis B surface antigen and only two patients were suffering from chancroid. Forty-six of these HIV-seropositive patients had already died. In order to cope with this epidemic, new models of care and cost-effective preventive measures are needed.

Antimicrobial activity of cefepime-tazobactam combination tested against clinical isolates of Enterobacteriaceae.

Antimicrobial activity of cefepime–tazobactam combination tested against clinical isolates of Enterobacteriaceae

Multilocus sequence analysis reveals high genetic diversity in clinical isolates of Burkholderia cepacia complex from India

Burkholderia cepacia complex (Bcc) is a complex group of bacteria causing opportunistic infections in immunocompromised and cystic fibrosis (CF) patients. Herein, we report multilocus sequence typing and analysis of the 57 clinical isolates of Bcc collected over the period of seven years (2005–2012) from several hospitals across India. A total of 21 sequence types (ST) including two STs from cystic fibrosis patient’s isolates and twelve novel STs were identified in the population reflecting the extent of genetic diversity. Multilocus sequence analysis revealed two lineages in population, a major lineage belonging to B. cenocepacia and a minor lineage belonging to B. cepacia. Split-decomposition analysis suggests absence of interspecies recombination and intraspecies recombination contributed in generating genotypic diversity amongst isolates. Further linkage disequilibrium analysis indicates that recombination takes place at a low frequency, which is not sufficient to break down the clonal relationship. This knowledge of the genetic structure of Bcc population from a rapidly developing country will be invaluable in the epidemiology, surveillance and understanding global diversity of this group of a pathogen.

Changing epidemiology of coagulase-negative staphylococci in normal flora of skin

Coagulase negative staphylococci (CoNS) have recently emerged as important pathogens causing nosocomial blood stream infections. To evaluate the prevalence of CoNS in cutaneous normal flora, skin swabs were collected from voluntary blood donors and processed for culture and identification using matrix assisted laser desorption ionisation-time of flight (MALDI-TOF). CoNS were isolated from 96% of blood donors, most commonly Staphylococcus hominis (86%), followed by Staphylococcus epidermidis (22%) and Staphylococcus haemolyticus (9%). There has been a shift in the prevalent species of CoNS in the community in India, from the earlier known S. epidermidis towards resistant species such as S. hominis and S. haemolyticus. Routine and rapid speciation of CoNS in clinical isolates with MALDI-TOF should be used effectively to manage these resistant species.

MALDI-TOF mass spectrometry: An emerging tool for unequivocal identification of non-fermenting Gram-negative bacilli

Background & objectives: Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) has been instrumental in revolutionizing microbiological identification, especially in high-throughput laboratories. It has enabled the identification of organisms like non-fermenting Gram-negative bacilli (NFGNB), which has been a challenging task using conventional methods alone. In this study an attempt was made to validate MALDI-TOF MS for the identification of clinical isolates of each of the three most common NFGNB, other than Pseudomonas spp., taking molecular methods as the gold standard. Methods: One hundred and fifty clinical isolates of NFGNB, confirmed by molecular methods such as Acinetobacter baumannii[oxa-51 polymerase chain reaction (PCR)], Burkholderia cepacia complex (expanded multilocus sequence typing) and Stenotrophomonas maltophilia (species-specific PCR), were taken. Isolated colonies from fresh cultures of all 150 isolates were smeared onto ground steel plate, with and without formic acid extraction step. The identification was carried out using MALDI-TOF MS Biotyper database. Results: A concordance of 100 and 73.33 per cent was found between the molecular techniques and MALDI-TOF MS system in the identification of these isolates up to genus and species levels, respectively. Using a cut-off of 1.9 for reliable identification, rate of species identification rose to 82.66 per cent. Principal component analysis dendrogram and cluster analysis further increased discrimination of isolates. Interpretation & conclusions: Our findings showed MALDI-TOF MS-based identification of NFGNB as a good, robust method for high-throughput laboratories.

Bacillus cereus causing intratumoral brain abscess

We report a case of intratumoral brain abscess due to Bacillus cereus in an adult male patient, which was managed successfully with excision of lesion and piperacillin-tazobactam for the duration of 5 weeks. To the best of our knowledge, this is a first case report of B. cereus infection leading to intratumoral brain abscess in a patient with a history of steroid administration by the intravenous route.

Serodiagnostic evaluation of recombinant CdtB of S. Typhi as a potential candidate for acute typhoid

Typhoid fever caused by human restricted Salmonella typhi presents a considerable health burden on developing South-Asian nations like India. The suboptimal sensitivity and specificity associated with culture-based isolation of etiological agent and the extensively used surface antigen-based serological assays often lead to misdiagnosis and inappropriate antimicrobial treatment. The increasing reports of the emergence of resistant strains and undefined disease burden signify the critical need for an inexpensive, reliable, easy-to-use, and highly sensitive diagnostic test for typhoid fever. Utilizing S. typhi-specific and immunogenic antigens in sero-diagnostic assays could lead to precise diagnosis of acute typhoid and prompt treatment. In this study, we report cloning, expression, and purification of recombinant Cytolethal distending toxin subunit B (CdtB) of S. typhi, which is reported to be highly specific, immunogenic, and expressed only upon S. typhi infection. We further evaluated the purified recombinant CdtB for its diagnostic potential in an IgM-based indirect ELISA format using 33 human samples. Twenty-one serum samples from blood culture confirmed cases (n = 21) of typhoid and 12 samples from healthy controls (n = 12) were tested. The assay showed sensitivity of 100% and specificity of 83.3% respectively with positive and negative predictive values of 91.3 and 100% respectively. Efficient detection of specific IgM antibodies indicates that CdtB could be highly valuable in sero-diagnosis of acute typhoid and rapid screening of clinical samples.

Draft Genome Sequence of Listeria monocytogenes Strain CIIMS-PH-1, a Serovar 4b Isolate from Infant Septicemia

ABSTRACT We report here the draft genome sequence of Listeria monocytogenes CIIMS-PH-1, an isolate obtained from a 16-day-old infant with septicemia. The draft genome of CIIMS-PH-1 consisted of 2,939,183 bp and is a member of sequence type 308, clonal complex 1, and lineage I.

Intrapleural streptokinase is effective and safe for children with multi-loculated empyema regardless of the time from disease onset

This study compared the efficacy of administering intrapleural streptokinase to children with multi‐loculated empyema within 14 days or at any time after disease onset.

Direct identification by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) from positive blood culture bottles: An opportunity to customize growth conditions for fastidious organisms causing bloodstream infections

Culture-negative bacteraemia has been an enigmatic entity with respect to its aetiological agents. In an attempt to actively identify those positive blood cultures that escape isolation and detection on routine workflow, an additional step of MALDI-TOF MS (matrix-assisted laser desorption ionization-time of flight mass spectrometry) based detection was carried out directly from the flagged blood culture bottles. Blood samples from 200 blood culture bottles that beeped positive with automated (BACTEC) system and showed no growth of organism on routine culture media, were subjected to analysis by MALDI-TOF MS. Forty seven of the 200 (23.5%) bacterial aetiology could be established by bottle-based method. Based on these results, growth on culture medium could be achieved for the isolates by providing special growth conditions to the fastidious organisms. Direct identification by MALDI-TOF MS from BACTEC-positive bottles provided an opportunity to isolate those fastidious organisms that failed to grow on routine culture medium by providing them with necessary alterations in growth environment.