Search

Maize stem borer (Chilo partellus) is considered a major threat for agricultural crops especially sorghum and maize and a main entomological research problem in the globe, especially in Pakistan. A study was conducted to check the life cycle of maize stem borer, C. partellus on maize under controlled conditions in 2019. The complete metamorphosis (egg, larva, pupa and adult) was recorded. The embryonic period was 4-6 days. The results showed that 1st, 2nd, 3rd, 4th, 5th and 6th instar period was 3.98 ± 1.00, 3.99 ± 2.76, 4.35 ±1.65, 4.15 ± 2.94, 5.23 ± 2.58 and 6.22 ± 2.37 days, respectively with 33.12± 9.25 days total larval period. Pupa was obtect and the fecundity was recorded 170-200 eggs per female. The pre-mating and mating period was lasted for 7-12 and 3-6 hours, respectively while the oviposition period lasted for 3-5 days. The total life cycle from egg to adult was 32-71 days. The current findings are very important in managing this pest on various crops around the globe especially in Pakistan. [ABSTRACT FROM AUTHOR]

Objectives: To compare antimicrobial resistance in S. Typhi and S. Paratyphi A isolates from Pakistan., Methods: Blood samples were collected through > 175 laboratory collection points in major cities and towns across the country. The study included 3,671 S. Typhi and 1,475 S. Paratyphi A isolates (2001-2006). Multidrug resistance (MDR) was defined as resistance to first-line agents co-trimoxazole, chloramphenicol and ampicillin., Results: In total, 79.3% S. Typhi and 59.9% S. Paratyphi A were isolated from patients under 15 years of age. During the study period, the MDR rate increased in S. Typhi (34.2 to 48.5% p<0.001). Quinolone resistance (MIC> 1 microg/ml) increased in both S. Typhi (1.6 to 64.1% p<0.001) and S. Paratyphi A (0 to 47% p<0.001). The increase in the proportion of strains showing high level quinolone resistance (MIC > 4 microg/ml) was greater in S. Paratyphi A when compared to S. Typhi. Resistance to first-line drugs was higher in those <15 years of age whereas quinolone resistance was higher in older patients., Conclusion: Differences between S. Typhi and S. Paratyphi A, in terms of evolution of resistance to first-line agents and to quinolones, are evident in this population. The rapid increase in quinolone resistance in S. Paratyphi A when compared to S. Typhi is concerning and requires further study.

Objective: To determine the validity of nalidixic acid screening test in the detection of high MICs of fluoroquinolone against Salmonella(S.) typhi isolated from blood and correlate zone diameters of ofloxacin with that of MIC value for nalidixic acid sensitive and resistant strains., Design: Cross-sectional analytical study., Place and Duration of Study: Clinical Microbiology Laboratory of the Aga Khan Hospital, Karachi from January 2002 to December 2003., Patients and Methods: Two hundred S. typhi isolates from blood were included for nalidixic acid screening and ofloxacin susceptibility. Antibiotic susceptibilities for both the antibiotics were obtained by disc diffusion method whereas MICs were determined by standard agar dilution method as recommended by NCCLS guidelines. Sensitivity, specificity and correlation between both antimicrobial susceptibility methods were calculated and results expressed as scattergrams., Results: The results broadly classify S. typhi isolates into nalidixic acid resistant strains with no zone of inhibition around 30 mug nalidixic acid disc and nalidixic acid sensitive strains with mean zone of inhibition of 24.9 mm. All S. typhi isolates with ofloxacin MIC of capital ZHE, Cyrillic 0.125 microg/ml were found to be nalidixic acid resistant (MIC capital ZHE, Cyrillic32 microg/ml) whereas the isolates with ofloxacin MIC 0.06 microg/ml were nalidixic acid sensitive (MIC 8 microg/ml). Screening for nalidixic acid resistance was found to be 100% sensitive and 97% specific in identifying S. typhi strains with reduced susceptibility to fluoroquinolone (MIC capital ZHE, Cyrillic 0.125 microg/ml)., Conclusion: Nalidixic acid resistance as a screening method is proved to be significant in identifying S. typhi isolates with reduced susceptibility to fluoroquinolones. It is also suggested that inhibition zone of 25 mm around 5 microg ofloxacin disc is appropriate as a selection criterion to detect S. typhi isolates with reduced susceptibility to fluoroquinolones.