METHODS: TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel. In vitro synergistic effect was checked using the chequerboard assay. ICR male mice were used to evaluate the in vivo toxicity and antibacterial activity of the hybrid peptides in a standalone form and in combination with ceftriaxone.
RESULTS: The results obtained from TEM and SEM indicated that the hybrid peptides caused significant morphological alterations in Streptococcus pneumoniae and disrupting the integrity of the cell wall/membrane. The rapid release of ATP from pneumococcal cells after one hour of incubation proposing that the antibacterial action for the hybrid peptides is based on membrane permeabilization and damage. The DNA retardation assay revealed that at 62.5 µg/ml all the hybrid peptides were capable of binding and preventing the pneumococcal genomic DNA from migrating through the agarose gel. In vitro synergy was observed when pneumococcal cells treated with combinations of hybrid peptides with each other and with conventional drugs erythromycin and ceftriaxone. The in vivo therapeutic efficacy results revealed that the hybrid peptide RN7-IN8 at 20 mg/kg could improve the survival rate of pneumococcal bacteremia infected mice, as 50% of the infected mice survived up to seven days post-infection. In vivo antibacterial efficacy of the hybrid peptide RN7-IN8 was signficantly improved when combined with the standard antibiotic ceftriaxone at (20 mg/kg + 20 mg/kg) as 100% of the infected mice survived up to seven days post-infection.
DISCUSSION: Our results suggest that attacking and breaching the cell wall/membrane is most probably the principal mechanism for the hybrid peptides. In addition, the hybrid peptides could possess another mechanism of action by inhibiting intracellular functions such as DNA synthesis. AMPs could play a great role in combating antibiotic resistance as they can reduce the therapeutic concentrations of standard drugs.
METHODS: The study was conducted over a span of three years with a total of 8142, 8134, and 8114 blood culture samples processed for the years 2008, 2009, and 2010 respectively. The minimum inhibitory concentration (MIC) for ciprofloxacin and chloramphenicol was determined using an agar dilution method. The MIC for ciprofloxacin was also confirmed by Epsilon-test (E -test) strips.
RESULTS: Of the total 302 Salmonella spp. isolated, 257 were Salmonella enterica serotype Typhi (85.1%) and 45 (14.9%) were S. enterica serotype Paratyphi A. The majority of the isolates recovered were from the pediatric age group (54.6%) and males (60.6%). Complete susceptibility was observed to chloramphenicol, cefotaxime, ceftriaxone, and azithromycin over the last two years (2009 and 2010), with an increase in resistance to nalidixic acid (100%) and ciprofloxacin (13.6%).
CONCLUSION: In our study, we found augmentation of resistance to nalidixic acid and fluoroquinolones and complete sensitivity to ceftriaxone along with reemergence of chloramphenicol sensitivity for Salmonella isolates. This report emphasises the necessity of continuous surveillance of antibiograms of enteric fever isolates in an area.
OBJECTIVE: To check the prices, availability, and affordability of the World Health Organization (WHO) key access antibiotics in private sector pharmacies of Lahore, Pakistan.
METHODOLOGY: A survey of WHO key access antibiotics from WHO essential medicine list 2017 was conducted in private sector pharmacies of 4 different regions of Lahore employing adapted WHO/HAI methodology. The comparison of prices and availability between originator brands (OB) and lowest price generics (LPG) were conducted followed by the effect of medicine price differences on patient's affordability. The data were analyzed using a preprogrammed WHO Microsoft excel workbook.
RESULTS: The mean availability of OB products was 45.20% and the availability of LPGs was 40.40%. The OBs of co-amoxiclav, clarithromycin and metronidazole and LPGs of azithromycin and ciprofloxacin were easily available (100%) in all private sector pharmacies. Whereas, antibiotics like chloramphenicol, cloxacillin, nitrofurantoin, spectinomycin, and cefazolin were totally unavailable in all the surveyed pharmacies. The OBs and LPGs with high MPRs were ceftriaxone (OB; 15.31, LPG; 6.38) and ciprofloxacin (OB; 12.42, LPG; 5.77). The median of brand premium obtained was 38.7%, which varied between the lowest brand premium of 3.97% for metronidazole and highest for ceftriaxone i.e. 140%. The cost of standard treatment was 0.5 day's wage (median) if using OB and 0.4 day's wage (median) for LPG, for a lowest paid unskilled government worker. Treatment with OB and LPG was unaffordable for ciprofloxacin (OB; 2.4, LPG; 1.1) & cefotaxime (OB; 12.7, LPG; 8.1).
CONCLUSION: There is dire need to properly implement price control policies to better regulate fragile antibiotic supply system so that the availability of both OB and LPG of key access antibiotics should be increased. The prices could be reduced by improving purchasing efficiency, excluding taxes and regulating mark-ups. This could increase the affordability of patients to complete their antibiotic therapy with subsequent reduction in antimicrobial resistance.