Detection and antibiotic susceptibility pattern of biofilm producing Gram positive and Gram negative bacteria isolated from a tertiary care hospital of Pakistan

Abstract

Microorganisms adhere to non-living material or living tissue, and form biofilms made up of extracellular polymers/slime. Biofilm-associated microorganisms behave differently from free-floating bacteria with respect to growth rates and ability to resist antimicrobial treatments and therefore pose a public health problem. The objective of this study is to detect the prevalence of biofilm producers among Gram positive and Gram negative bacteria isolated from clinical specimens, and to study their antimicrobial susceptibility pattern. The study was carried out from October 2009 to March 2010, at the Department of Microbiology, Army Medical College/ National University of Sciences and Technology (NUST), Rawalpindi, Pakistan. Clinical specimens were received from various wards of a tertiary care hospital. These were dealt by standard microbiological procedures. Gram positive and Gram negative bacteria isolated were subjected to biofilm detection by congo red agar method (CRA). Antimicrobial susceptibility testing of those isolates, which showed positive results (slime production), was done according to the Kirby-Bauer disc diffusion technique. A total of 150 isolates were tested for the production of biofilm/slime. Among them, 81 isolates showed positive results. From these 81, 51 were Gram positive and 30 were Gram negative. All the 81(54%) slime producers showed reduced susceptibility to majority of antibiotics. Bacterial biofilms are an important virulence factor associated with chronic nosocomial infection. Detection of biofilm forming organisms can help in appropriate antibiotic choice.

Prevalence of AmpC β-lactamase in Clinical Isolates of Escherichia coli, Klebsiella spp., and Proteus mirabilis in a Tertiary Hospital in Tehran, Iran

“…In a study by Shafiq et al (2) in Pakistan, of 55/103 positive-screen AmpC-producing isolates, 7.9% of E. coli and 12.37% of Klebsiella isolates carried AmpC genes. In another study in Pakistan (2,18), the rates were 18% and 14% in isolates of E. coli and Klebsiella, respectively, which were closer to our findings. However, Fam et al (10) reported that the prevalence of plasmidmediated AmpC genes were significantly higher in Klebsiella isolates compared to E. coli (43.5% versus 17.7%) (10).…”

Determination of correlation between biofilm and extended spectrum β lactamases producers of Enterobacteriaceae

“…[12,13] A total 169 isolates of Enterobacteriaceae were tested for biofilm production by tube adherence method which can be indicated for the routine detection of biofilm production because of its easy application and low-cost and because it guarantees reliable results with excellent sensitivity and specificity. [14,15] In our study, 59.2% of the tested organisms have shown the potential to make biofilms in comparison to similar study [16] which reported 54%.…”

Synergistic Effect of Combined Antibiotic and Methanol Extract of Eucalyptus camaldulensis leaf Against Staphylococcus aureus and Pseudomonas aeruginosa

“…Biofilm producing bacteria are responsible for many recalcitrant infections and are notoriously difficult to eradicate. They exhibit resistance to antibiotics by various methods like restricted penetration of antibiotic in to biofilm, decreased growth rate and expression of resistance genes (Hassan et al, 2011). As a consequence of biofilm development, it is said that the ability of organisms to transfer genes horizontally will be enhanced within these micro communities thus facilitating the spread of antibiotic resistance (Sasirekha et al, 2012).…”