The resistance phenotypes and genomic diversity of 185 Acinetobacter baumannii isolates obtained from the intensive care unit (ICU) of a local teaching hospital in Kuala Lumpur from 2006 to 2009 were determined using antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Antibiogram analyses showed that the isolates were fully resistant to β-lactam antimicrobials and had high resistance rates to the other antimicrobial agents tested. However, the isolates were susceptible to polymyxin B. Resistance to cefoperazone/sulbactam was only detected in strains isolated from 2007 to 2009. Some environmental isolates and an isolate from the hands of a healthcare worker (HCW) had identical resistance profiles and PFGE profiles that were closely related to patient isolates. Cluster analyses based on the PFGE profiles showed there was a persistent clone of endemic isolates in the ICU environment. The transmission route from HCWs to fomites to patients, which caused a long-term infection in the ICU of the University Malaya Medical Centre, was observed in this study. These data provide a better understanding of A. baumannii epidemiology within the hospital and the possible transmission routes. Knowledge of changes in the resistance rates of A. baumannii in our local hospital will improve antimicrobial therapy.
A wild-type, Gram-positive, rod-shaped, endospore-forming and motile bacteria has been isolated from palm oil mill sludge in Malaysia. Molecular identification using 16S rRNA gene sequence analysis indicated that the bacteria belonged to genus Paenibacillus. With 97 % similarity to P. alvei (AUG6), the isolate was designated as P. alvei AN5. An antimicrobial compound was extracted from P. alvei AN5-pelleted cells using 95 % methanol and was then lyophilized. Precipitates were re-suspended in phosphate buffered saline (PBS), producing an antimicrobial crude extract (ACE). The ACE showed antimicrobial activity against Salmonella enteritidis ATCC 13076, Escherichia coli ATCC 29522, Bacillus cereus ATCC 14579 and Lactobacillus plantarum ATCC 8014. By using SP-Sepharose cation exchange chromatography, Sephadex G-25 gel filtration and Tricine SDS-PAGE, the ACE was purified, which produced a ~2-kDa active band. SDS-PAGE and infrared (IR) spectroscopy indicated the proteinaceous nature of the antimicrobial compound in the ACE, and liquid chromatography electrospray ionization mass spectroscopy and de novo sequencing using an automatic, Q-TOF premier system detected a peptide with the amino acid sequence F-C-K-S-L-P-L-P-L-S-V-K (1,330.7789 Da). This novel peptide was designated as AN5-2. The antimicrobial peptide exhibited stability from pH 3 to 12 and maintained its activity after being heated to 90 °C. It also remained active after incubation with denaturants (urea, SDS and EDTA).