Antimicrobial susceptibility patterns of multidrugresistant Pseudomonas aeruginosa and Acinetobacter baumannii against carbapenems, colistin, and tigecycline

To examine susceptibility of Pseudomonas aeruginosa [P. aeruginosa] and Acinetobacter baumannii [A. baumannii] against carbapenems along with colistin and tigecycline as alternative therapeutic options. A total of 117 strains of multidrug-resistant [MDR] non-fermenting Gram negative bacteria isolated from non-duplicate samples were collected consecutively. We included one sample from each patient [84 isolates of A. baumannii and 33 isolates of P. aeruginosa isolated from patients seen at King Khalid University Hospital, Riyadh, Saudi Arabia, from June to December 2010]. Isolates were identified by the MicroScan WalkAway 96 Plus system. The minimum inhibitory concentrations [MICs] were determined by E-test following the Clinical and Laboratory Standards Institute breakpoint recommendations. Most A. baumannii strains were resistant to imipenem [90.5%], meropenem [90.5%], and doripenem [77.4%]. Whereas, a higher percentage of P. aeruginosa was resistant to imipenem [90.9%], and meropenem [81.8%], only 39.4% were resistant to doripenem. Colistin had excellent activity against both A. baumannii [100%] and P. aeruginosa [93.9%], while 89.3% of A. baumannii strains were susceptible to tigecycline. Among the carbapenems, doripenem was found to be the most potent antimicrobial agent against P. aeruginosa, whereas colistin proved to be an effective alternative antimicrobial agent for treatment of A. baumannii or P. aeruginosa. Tigecycline remains the best therapeutic option for MDR A. baumannii

Inhibition of growth of Leishmania donovani promastigotes by newly synthesized 1,3,4-thiadiazole analogs

Leishmania donovani, the causative agent of visceral leishmaniasis, is transmitted by sand flies and replicates intracellularly in their mammalian host cells. The emergence of drug-resistant strains has hampered efforts to control the spread of the disease worldwide. Forty-four 1, 3, 4-thiadiazole derivatives and related compounds were tested in vitro for possible anti-leishmanial activity against the promastigotes of L. donovani. Micromolar concentrations of these agents were used to study the inhibition of multiplication of L. donovani promastigotes. Seven compounds were identified with potential antigrowth agents of the parasite. Compound 4a was the most active at 50 micro M followed by compound 3a. These compounds could prove useful as a future alternative for the control of visceral leishmaniasis