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Bimal K Das

Publications and source records attributed to Bimal K Das.

At least 19 recordsLinked to original sources
PubMed2006

Citrobacter infections in a tertiary care hospital in Northern India.

OBJECTIVES: This prospective study was carried out to look for the frequency of isolation of Citrobacter species from clinical specimens and study their antimicrobial susceptibility pattern. METHODS: Patients from whom Citrobacter species were isolated during routine diagnostic testing from January to December 2004 were included in the study. Isolates were identified by standard biochemical tests. Antimicrobial susceptibility testing was performed by disk diffusion method as per National Committee of Clinical Laboratory Standards (NCCLS) guidelines. RESULTS: Citrobacter species were isolated from a total of 205 patients. Infection was nosocomially acquired in 94.6% patients. One hundred eighty one (88.3%) patients had significant underlying illnesses. Culture yielded Citrobacter koseri in 185 (90.2%) and Citrobacter freundii in 20 (9.8%) patients. The distribution of isolates was as follows: urine (46.2%), respiratory tract (16.3%), blood (15.8%), pus (12.1%) and sterile body fluids (9.3%). Drug resistance was observed to be more in C. koseri as compared to C. freundii. CONCLUSIONS: Citrobacter infections are often nosocomially acquired, seen in patients with significant underlying diseases and isolates are commonly drug-resistant. Adoption of hospital infection control practices and a good antibiotic policy may prevent their spread.

Adolescent↗
PubMed2006

Emerging resistance to carbapenems in a tertiary care hospital in north India.

BACKGROUND AND OBJECTIVES: Carbapenems are beta-lactam antibiotics, presently considered as most potent agents for treating multi-drug resistant Gram-negative bacilli infections. In India carbapenems available for use are meropenem and imipenem, introduced recently. Resistance to these has been reported in a few bacteria especially Pseudomonas spp. We therefore retrospectively evaluated the antibiotic susceptibility pattern to these agents amongst various clinical isolates in a tertiary care hospital in north India. METHODS: In this study Gram-negative bacterial pathogens isolated from clinical samples were tested for extended spectrum beta lactamase (ESBL) production. All ESBL positive bacteria were tested for meropenem and imipenem activity pattern using NCCLS guidelines. A total of 2626 consecutively isolated Gram-negative bacteria, which tested positive for ESBL production by the double disk diffusion method, were included. RESULTS: The different bacteria isolated were Pseudomonas spp. 759, Acinetobacter spp. 676, Escherichia coli 569, Klebsiella spp. 343, Enterobacter spp. 150, Citrobacter spp. 57 and Proteus spp. 72. Overall resistance to meropenem was more (22.16%) than imipenem (17.32%). Maximum resistance was seen in Pseudomonas spp. M(R) 37.6 per cent, I(R) 30 per cent. In isolates from intensive care units (ICU) resistance to carbapenems was significantly higher than non-ICU patients. INTERPRETATION AND CONCLUSION: Resistance to meropenem and imipenem was seen in various clinical isolates of Gram-negative ESBL-positive bacteria. There is a need to alarm our clinicians for judicious use of antibiotics.

Anti-Bacterial Agents↗
PubMed2005

Brain abscess due to Enterococcus avium.

We report the first case of brain abscess due to Enterococcus avium in a 19-year-old man with chronic otitis media since childhood. The patient presented to the emergency department in a comatose condition. Contrast-enhanced brain computed tomography scan showed a hypodense area with ring enhancement in the right temporal lobe and mass effect with subfalcine and transtentorial herniation. Emergency temporal burr hole operation was performed and pus drained out, but the patient succumbed to his illness. Culture of the aspirated pus yielded growth of gram-positive cocci identified as E avium, an infrequent pathogen of human infections. The association of E avium with brain abscess further extends the clinical spectrum of this rare pathogen.

Adult↗
PubMed2005

Enterococcal bacteraemia in a tertiary care hospital of North India.

A prospective study was conducted to determine clinical and bacteriologic features and antibiotic resistance pattern of enterococci isolated from cases of bacteraemia over a 7-month period. A total of 103 patients were identified during the study period whose blood culture was found to be positive for Enterococcus species. Bacteraemia was nosocomially acquired in 100 patients and community acquired in three. Enterococcus faecalis was isolated in 99 patients and E faecium in four. Bacteraemia was polymicrobial in 34 patients. Majority of patients had serious underlying diseases and were on prior therapy with cephalosporins. A source of bacteraemia was found in 59 patients (57.2%); intravascular catheters being the most common identifiable source. Overall mortality rate was 5.8%. High level aminoglycoside resistance was found in 76 (73.8%) of the enterococcal isolates. Vancomycin resistance was not found in any of the isolates. Bacteraemia due to enterococci is emerging as a significant clinical problem in hospital settings. A watchful vigilance is therefore required as regards their antibiotic resistance pattern particularly high level aminoglycoside resistance and vancomycin resistance. In addition hospital practices like prolonged use of in situ catheters and inadvertent antibiotic usage need to be minimised.

Adolescent↗
PubMed2005

Species prevalence and antimicrobial susceptibility of enterococci isolated in a tertiary care hospital of North India.

The present prospective study was carried out to determine the species distribution and antimicrobial susceptibilities of enterococci isolated from clinical samples in a tertiary care hospital of North India. Enterococcus species isolated from blood, urine, pus, sterile fluids and the hospital environment from October 2003 to January 2004 were identified by standard biochemical tests. Antimicrobial susceptibility testing was performed by the disk diffusion method as per NCCLS guidelines. Out of a total of 105 Enterococcus species recovered during the study period, E. faecium (42.90%) and E. faecalis (40.00%) constituted the predominant isolates. Enterococcus faecium was the commonest blood culture isolate while E. faecalis predominated pus and urine samples. Other species isolated were E. mundtii, E dispar, E. durans, E. avium, E. raffinosus and E. gallinarum. High-level aminoglycoside resistance was detected in 73.3% of isolates. Resistance to vancomycin, teicoplanin and linezolid was not detected. Prevalence of a wide variety of Enterococcus species in clinical samples together with their variable antimicrobial susceptibility patterns emphasizes the need for routinely carrying out detailed speciation and in vitro susceptibility testing of enterococcal isolates in the clinical bacteriology laboratory.

Anti-Bacterial Agents↗
PubMed2005

Comparative in vitro activity of beta-lactam/beta-lactamase inhibitor combinations against gram negative bacteria.

BACKGROUND & OBJECTIVE: Currently, the use of beta-lactamase inhibitors in combination with beta-lactam antibiotics represents an effective measure to combat a specific resistance mechanism of beta-lactamase producing organisms. Knowledge about the susceptibility profile of bacteria to different combination agents available is essential to guide appropriate treatment of severe infections in hospitalized patients. The present study compares the in vitro activity of three commercially available beta-lactam/beta-lactamase inhibitor combinations (piperacillin/tazobactam, cefoperazone/sulbactam, ticarcillin/clavulanic acid) against beta-lactamase producing gram negative bacteria in a tertiary care hospital in north India. METHODS: A total of 9004 consecutively isolated extended spectrum beta-lactamase (ESBL) producing gram negative bacteria isolated from various clinical samples from patients admitted to the All India Institute of Medical Sciences, New Delhi, from September 2003 to August 2004 were included in the study. These isolates were screened for ESBL production by the inhibitor based test recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Antibiotic susceptibility testing was carried out by disc diffusion method as per NCCLS guidelines. RESULTS: Of the 9004 isolates tested, 3232 (35.89%) were sensitive and 568 (6.31%) were resistant to all three combination agents, and rest 5204 (57.80%) were resistant to at least one of the combinations. Susceptibility to piperacillin/tazobactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid was 81.37, 76.06 and 45.48 per cent respectively. Piperacillin/tazobactam exhibited significantly (P<0.05) greater antimicrobial activity against Pseudomonas spp., Escherichia coli and Klebsiella spp. compared to cefoperazone/sulbactam. INTERPRETATION & CONCLUSION: Overall piperacillin/tazobactam was observed to be the best combination agent followed by cefoperazone/sulbactam in our setting. This difference in activities of these combination agents needs to be evaluated further by ascertaining their efficacy in clinical studies.

Anti-Bacterial Agents↗
PubMed2004

Streptococcus pyogenes meningitis.

Group A Streptococcus (GAS) is a rare cause of meningitis. Although it has a high mortality, the condition is easily treatable if diagnosed early since the bacteria retains its sensitivity to many antimicrobials. The authors report here two cases of GAS meningitis along with a review of world literature.

Anti-Bacterial Agents↗
PubMed2004

Seasonality and antimicrobial resistance pattern of Vibrio cholerae in a tertiary care hospital of North India.

We retrospectively analysed the seasonal distribution of cholera and the antimicrobial resistance pattern of Vibrio cholerae isolates over a 5-year period from January 1998 to December 2002. Of 3213 stool specimens processed from 3213 patients with acute watery diarrhoea during this period, 431 samples (13.4%) were found positive for V. cholerae. There were 423 V. cholerae O1 biotype E1 Tor, 2 V. cholerae O139 and six isolates of non-O1 non-O139. The highest number of cholera cases occurred in May-June followed by July-August. Cases started appearing in April for all years except in the year 2002 when three cases occurred in the first week of March. A large number (90.25% strains) were resistant to at least one antibiotic.

Anti-Infective Agents↗
PubMed2004

The study of bacterial flora of different types in hospital waste: evaluation of waste treatment at Aiims Hospital, New Delhi.

Bio-medical waste management rules were formulated in response to the worldwide public concern over medical waste. The practice of separation into different types of waste in health care institutes should be evaluated more scientifically. Due to a lack of data from the Indian sub-continent, this study was initiated at a tertiary care hospital. Samples were collected from different types of waste at the hospital, at different time intervals, for microbiological evaluation. The results reveal that the microbial flora isolated from infectious waste and general waste from the hospital are similar. The samples from general waste in this study reveal many types of pathogens. The bacteria present in the waste initially was low in quantity, but they replicated rapidly over time so that significant numbers were detected by 24 hours, due to environmental factors which were favorable for growth during this period. This study strongly suggests that waste should be removed from the hospital within 24 hours of its generation to prevent environmental contamination caused by any accidental spillage of waste. General waste generated in the hospital should be treated similar to infectious waste, as it can be equally hazardous.

Bacteria↗
PubMed2003

Molecular mechanism of action of major Helicobacter pylori virulence factors.

Although Helicobacter pylori infects 50% of the total human population, only a small fraction of the infected people suffer from severe diseases like peptic ulcers and gastric adenocarcinoma. H. pylori strains, host genotypes and environmental factors play important role in deciding the extent and severity of the gastroduodenal diseases. The bacteria has developed a unique set of virulence factors to survive in the extreme ecological niche of human stomach. Together these virulence factors make H. pylori one of the most successful human pathogenic bacteria colonizing more than half of the human population. Understanding the mechanism of action of the major H. pylori virulence factors will shed light into the molecular basis of its pathogenicity.

Adhesins, Bacterial↗
PubMed2003

Infection with an extended-spectrum beta-lactamase-producing strain of Serratia marcescens following tongue reconstruction.

We report a case of postsurgical wound infection of polymicrobial etiology caused by Serratia marcescens and Pseudomonas aeruginosa following the use of a radial forearm free flap for oncological tongue reconstruction. S. marcescens was a producer of SHV-12 extended-spectrum beta-lactamase (ESBL). This is the first report from India of this ESBL. S. marcescens and P. aeruginosa were resistant to the empirical perioperative antibiotics administered. Delay in the recognition of the type of infection and in the institution of appropriate therapy resulted in total loss of the free flap.

Adult↗
PubMedDate not supplied

In vitro efficacy of ciprofloxacin and gentamicin against a biofilm of Pseudomonas aeruginosa and its free-living forms.

BACKGROUND: Infection with Pseudomonas aeruginosa is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). With chronicity of infection, the organism acquires a mucoid phenotype and grows as microcolonies in a biofilm in the respiratory passages of the host. This acts as a protective niche and helps the organism to evade the host immune response. In the biofilm the organism has a high resistance to antibiotics, leading to problems in eradication, and poses a therapeutic challenge. We studied the antimicrobial susceptibility of P. aeruginosa ATCC 27853 in a biofilm and as free-living forms against ciprofloxacin and gentamicin, the commonly used antibiotics in patients with CF. METHODS: Biofilm formation of P. aeruginosa ATCC 27853 was characterized by in vitro biofilm formation assay. The biofilm was detected by light microscopy and quantitated by measuring the absorbance at 575 nm and by viable bacterial counts. After the maximal biofilm was established, the effect of various concentrations of ciprofloxacin (1, 2 and 4 microg/ml) and gentamicin (4, 8, 16, 32 and 64 microg/ml) was observed and the minimal biofilm eradication concentration (MBEC) determined. The minimal bactericidal concentration (MBC) of both the antibiotics was determined against the free-living forms of the organism. The MBEC of the two antibiotics was further compared with the MBC. RESULTS: On microscopic examination, the maximal biofilm of P. aeruginosa was established on a coverslip at 12 hours, the maximum absorbance was at 575 nm and viable counts were observed at 12 hours, which corresponded to the maximal biofilm production. The organisms in the biofilm showed a 4-fold greater resistance against ciprofloxacin and gentamicin as compared to the free-living forms. CONCLUSION: In biofilm, P. aeruginosa shows greater resistance against antibiotics. This renders these antibiotics ineffective, leading to chronic and persistent infections.

Biofilms↗