Prevalence and Susceptibility Profiles of Nonfermentative Gram-negative Bacilli Infection in a Tertiary Care Hospital of Eastern India.

Background: Nonfermentative gram-negative bacilli (NFGB) have emerged as a major cause of nosocomial infections.This study was undertaken to know the prevalence of nonfermenters isolated from different clinical samples along with their susceptibility profile. Material and methods: Conventional bacteriological methods were used for identification and susceptibility testing of nonfermenters. Susceptibility testing was performed by methods as recommended by Clinical Laboratory Standard Institute (CLSI). Results: Out of the total 1,650 clinical samples received NFGB were found in 201 samples with an isolation rate of 12.18%. Nonfermenters isolated were Pseudomonas aeruginosa (50.24%), Acinetobacter baumannii (24.87%), Acinetobacter lowffii (5.47%), Pseudomonas fluorescens (1.49%), Pseudomonas stutzeri (1.99%), Burkholderia cepacia (6.96%), Stenotrophomonas maltophilia (2.98%), Achromobacter xylosoxidan (3.98%) and Shewanella putrefaciens (1.99%). Most of the isolated organisms were multidrugresistant (MDR). P. aerurginosa showed good sensitivity to imipenem (91.08%), cefoperazone sulbactum (68.31%) combination, amikacin (69.30%) and colistin (100%). A. baumannii showed 90% sensitivity to imipenem and 94% to colistin. Conclusion: Our study showed that prevalence of NFGB amongst different clinical isolates is significantly high especially in this part of the world and these organisms are often MDR. In this scenario, we propose all laboratory samples should be screened for NFGB even in clinically unsuspected cases. P. aeruginosa showed good sensitivity to colistin, imipenem, amikacin and cefoperazone sulbactum combination while A. baumannii showed good sensitivity to imipenem and colistin.

Prevalence of Nonfermentative Gram Negative Bacilli In Seriously ill Patients With Bacteraemia.

Bacteraemia due to nonfermentative gram negative bacilli appears to be increasing in frequency particularly in hospitalized patients with severe underlying illness. A total of 159 (79.50%) organisms were isolated from blood cultures of 200 seriously ill patients. Out of these, 73 (45.91%) were nonfermentative gram negative bacilli. Pseudomonas aeruginosa was the commonest isolate (32.88%) followed by Acinetobacter spp. (23.28%) and Burkholderia cepacia (10.96%). Analysis of antimicrobial susceptibility testing showed multidrug resistant pattern with majority of the isolates being resistant to three or more drugs.

In Vitro Antimicrobial Activities of NanoSilver-coated Gauze against Clinical Isolates / 대한임상미생물학회지

BACKGROUND: It is well-known that silver ions and silver compounds are broad-spectrum antimicrobial agents effective against gram-positive and gram-negative bacteria, and yeasts. Thus, silver ions, as an antibacterial agent, have been used in the components of materials used in medical devices or coatings. Recently, advances in nanotechnology have enabled manufacturers to develop silver particles of a nanometer size with a safer and more effective antimicrobial activity. So, we evaluate the antimicrobial activity of nanoSilver-coated gauze against clinical isolates. METHODS: Three kinds of nanoSilver-coated gauzes (100A, 800A, and 1,500A) were tested for antimicrobial activity by the disk diffusion method. The organisms tested included clinical isolates of nonfermentative gram-negative bacilli (143 isolates), aerobic gramnegative bacteria (188), aerobic gram-positive bacteria (397), anaerobic bacteria (46), and yeasts (161), and three reference ATCC strains. RESULTS: The susceptible rates to NanoSilver of nonfermentative gram-negative bacilli (NFB), aerobic gramnegative bacteria and aerobic gram-positive bacteria were 87%, 87% and 78%, respectively. Antimicrobial activity of NanoSilver against imipenem-resistant NFB, extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae, and methicillin-resistant Staphylcoccus aureus (MRSA) was similar to that against imipenem-sensitive NFB, ESBL non-producing Enterobacteriaceae, and methicillin-susceptible S. aureus. CONCLUSION: NanoSilver-coated gauze exhibits broad spectrum antimicrobial activities to a large number of gram-negative and gram-positive bacteria including imipenem-resistant NFB, ESBL producing Enterobacteriaceae, and MRSA.

Identification System of Nonfermentative Gram Negative Bacilli Using Microplate / 대한임상미생물학회지

BACKGROUND: The accurate and rapid identification (ID) of nonfermentative gram-negative bacilli (NFB) is essential for diagnostic and therapeutic purposes and for epidemiologic studies of hospital infections. Commercial identification systems of NFB are easy to use but too expensive. The aim of the study was to develop a simple system for the identification of NFB species which are frequently isolated from clinical specimens. METHODS: Eighteen biochemical tests used in NFB microplate ID system were pyocyanin in Tech media; pyoverdin in Flo media; glucose fermentation, acid formation from glucose, maltose, lactose, sucrose, and mannitol in oxidation-fermentation media; Nitrate and nitrite reduction in nitrate media; fornithine decarboxylase, lysine decarboxylase, and arginine dihydrolase in Moeller decarboxylase media; acetamide, urease, citrate, 42degrees C growth, and oxidase test. For the establishment of NFB's biochemical data in microplate ID system, 175 consecutive isolates of NFB from clinical specimens isolated during the period of April 2000 were simultaneously tested by microplate method and API 32GN. RESULTS: Ninety-two percent of clinical isolates of NFB were identified to the species level by NFB microplate ID system. CONCLUSIONS: The NFB microplate ID system is simple to use, rapid and economical. Further modification are needed to improve the accuracy and identification rate of NFB isolates.