Antibacterial activity and bioactive compounds of 50％ hydroethanolic extract of Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm

Objective: To evaluate antibacterial activity and the bioactive compounds of 50％ hydro-ethanolic extract of Alpinia zerumbet (A. zerumbet) rhizomes. Methods: Eight reference microbial strains including two Gram-positive bacteria [Staphylococcus aureus (ATCC 29213) and Enterococcus faecalis (ATCC 29212)] and six Gram-negative bacteria [Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATTC 700603), Proteus mirabilis (DMST 8212), Salmonella enterica subsp. enterica serovar Vellore. (ATCC 15611), Shigella flexneri (ATCC 12022) and Pseudomonas aeruginosa (ATCC 27853)], were used to test antimicrobial susceptibility by the broth microdilution method. Bioactive compounds were analyzed by using HPLC. Results: The minimum inhibitory concentration values of A. zerumbet extract were 8 mg/mL for Staphylococcus aureus, Escherichia coli and Shigella flexneri and 16 mg/mL for Enterococcus faecalis and the other four Gram-negative bacilli. HPLC chromatograms revealed that the A. zerumbet extract contained hydroxybenzoic acids, hydroxycinnamic acids and flavonoids. Conclusions: The constituents of A. zerumbet rhizomes could be a potential source of antibacterial compounds, warranting further study of A. zerumbet extract.

CTX-M extended-spectrum beta-lactamases among clinical isolates of Enterobacteriaceae in a Thai university hospital.

This study presents updates on molecular epidemiology of extended-spectrum beta-lactamases (ESBLs) in clinical isolates of Enterobacteriaceae from Srinagarind Hospital, Khon Kaen University, Thailand. All isolates were screened for the presence of ESBL genes, bla(TEM), bla(SHV), bla(VEB) and bla(CTX-M), using PCR followed by nucleotide sequence determination. The results revealed that beta-lactamase genes among 48 isolates collected between 1998 and 1999 were bla(SHV) (79%), bla(CTX-M-9) (52%), bla(TEM-1) (48%) and bla(VEB) (33%), whereas those found in 52 isolates collected in 2003 were bla(TEM-1) (79%), bla(CTX-M-15) (44%), bla(SHV) (36%), bla(VEB) (36%), bla(CTX -M-14) (11%) and bla(CTX-M-9) (10%). In addition, 45 isolates carried at least two different ESBL genes. Using PCR, part of insertion sequence ISEcpl was found in the upstream regions of bla(CTX-M-14) and bla(CTX-M-15). ERIC-PCR analysis revealed that most ESBL-producing isolates were of different strains. This is the first report of CTX-M-9, CTX-M-14 and CTX-M-15 beta-lactamase genes in Enterobacteriaceae in Thailand.

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks.

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen isolates of hVISA and 22 of vancomycin-sensitive S. aureus (VSSA) were included. The organisms were tested by the disk diffusion method, using 15-microg vancomycin disks on four different media: Mueller-Hinton agar (MHA), MHA plus 2% NaCI (MHAS), Brain Heart Infusion agar (BHA), and BHA plus 2% NaCl (BHAS). In addition, two different inoculum sizes, bacterial suspensions adjusted to 0.5 and 2.0 McFarland, were tested. The inhibition zone was read independently by three medical technologists after incubation at 37 degrees C for 24 and 48 hours. The use of MHAS with an inoculum size of 2.0 McFarland and 48-hour incubation period yielded the highest sensitivity (94.4%), specificity (81.8%), positive predictive value (80.9%), and negative predictive value (94.7%). The disk diffusion test with 15-microg vancomycin disk is simple and may be used as a screening method for the detection of hVISA.

Etiologies and treatment outcomes for out-patients with community-acquired pneumonia (CAP) at Srinagarind Hospital, Khon Kaen, Thailand.

Most patients with community-acquired pneumonia are treated as out-patients with empirical therapy, since initially the etiologic agent is unknown. We prospectively assessed the etiologies and treatment outcomes of pneumonia from February 2003 to 2004 at ambulatory clinics. Forty-four patients were included with a mean age of 49.2 (SD 18.2) years. The male to female ratio was 1:1.4. The incubation period was 6.9 (SD 4.4) days. Half of the patients were healthy. Asthma and COPD were common in patients with underlying diseases. The etiologic diagnosis was determined by a sputum culture and a serology test of paired serum samples. Hemo-culture produced no growth in any patients. Atypical pathogens and H. influenzae were the most common finding, each occurring in 31.8% of the patients followed by S. pneumoniae and H. parainfluenzae (27.3% each). Twenty-two patients were infected with multiple pathogens. C. pneumoniae was the most common co-infecting pathogen. Two of 12 S. pneumoniae isolates were penicillin resistant. Nine of 14 H. influenzae isolates were cotrimoxazole resistant and 8 of 14 were not sensitive to erythromycin. For H. parainfluenzae, 11 of 12 isolates were not sensitive to erythromycin, and 7 of 12 were not sensitive to cotrimoxazole. Oral antibiotics were prescribed as out-patient treatment. Forty patients (90.9%) improved, with symptoms-score improvement averaging 6.4 days. Four patients got worse and needed a change of antibiotics, the symptoms usually worsen within 3-5 days. We conclude that, antibiotics for CAP out-patients should cover atypical pathogens, H. influenzae, S. pneumoniae and H. parainfluenzae. If the clinical symptoms do not respond after 3-5 days of out-patient treatment, resistance or an unusual organism (eg B. pseudomallei) should be considered.