ABSTRACT
Methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative staphylococci (MRCoNS) are the important nosocomial infectious agents. There is a growing concern about the rapid rise in the resistance of Staphylococcus aureus to presently available antimicrobial agents. The aim of this study was to evaluate the prevalence rate of MRSA and MRCoNS and their rate of resistance to different antistaphylococcal antibiotics used broadly for treatment. Out of the total 350 staphylococcal isolates from different clinical specimens 148 isolates (60.40%) were identified as MRSA by oxacillin screen agar method, and 46 isolates (43.80%) were screened as MRCoNS. All the MRSA and MRCoNS isolates were tested for antibiotic resistance pattern by disc diffusion method for 16 different antibiotics. All the isolates of MRSA and MRCoNS were multi-drug resistant. Antibiotic resistance pattern of these isolates was high against penicillin. All the MRSA strains were resistant to penicillin and oxacillin (100%), followed by cephalothin and nalidixic acid (89.18%), cotrimoxazole (86.48%), erythromycin (85.81%), cephalaxin and cephradine (83.10%), levofloxacin (80.40%), imipenem (77.70%), gentamicin (76.35%), tetracycline (59.45%), ciprofloxacin (44.59%), chloramphenicol (18.24%) and rifampicin (10.13%). The MRCoNS strains also showed closely similar drug resistance pattern with 97.82% isolates being resistant to penicillin, followed by oxacillin (95.65%), cephalothin (86.95%), cephradine (82.60%), levofloxacin and nalidixic acid (80.43%), erythromycin, cephalaxin and imipenem (78.26%), cotrimoxazole (73.91%), gentamicin (69.56%), ciprofloxacin and tetracycline (63.04%), chloramphenicol (13.04%) and rifampicin (6.52%). However, all the MRSA and MRCoNS isolates, even those with very high oxacillin MIC (>130 μg/ml) were uniformly susceptible to vancomycin. Chloramphenicol and rifampicin also showed excellent activity against methicillin-resistant isolates. Overall, data presented in this study indicated a slightly higher methicillin resistant rate in MRSA compared to MRCoNS strains. Multi-drug resistance rates in our MRSA and MRCoNS isolates were, 58.10 and 32.60%, respectively. Application of ß-lactamase production method revealed that 84% of MRSA and 87% of MRCoNS strains tested positive for the ß-lactamase production. This study indicated a high level prevalence of MRSA and MRCoNS strains resistance against widely used antimicrobial agents. An appropriate knowledge on the current antibiotic susceptibility pattern of MRSA and MRCoNS is essential for appropriate therapeutic regime determination.
ABSTRACT
Southern corn leaf blight caused by Cochliobolus heterostrophus is a major foliar disease of maize crop in Pakistan. The disease affects leaves, leaf sheaths, ears and maize grains. Suitable physiological conditions which include different nutrient media, temperature, pH, carbon and nitrogen sources were determined for growth and reproduction of the pathogen. Among all media used viz, the best supporting medium was found to be Richard’s agar for the growth of pathogen after 7 days of incubation. Different temperatures (20, 25, 30 and 35ºC) were selected for mycelia growth of the pathogen, among which maximum growth was found to be at 30ºC (80 mm colony size) and minimum at 35ºC (35 mm). Maximum radial colony growth of the pathogen was observed at neutral pH (80 mm). Sucrose and potassium nitrate (KNO3) were found to be the most appropriate sources of carbon and nitrogen respectively.
ABSTRACT
Present research was aimed towards designing and construction of efficient plastic media-trickling filter (TF) for the treatment of domestic wastewater. The hydraulic flow rate through the TF was maintained at 80±2 ml/min at a temperature range of 5-15ºC by selecting treatment time of 12, 24, 36 and 48 hrs. Parameters like COD, BOD5, TSS, turbidity, NO3, NO2, SO4, PO4 and pathogenic indicator microbes were monitored after treatment of 12, 24, 36 and 48 hrs. The efficiency of the TF was improved with increase of time from 12 to 48 hrs. Maximum efficiency of TF was observed after 48 hrs treatment viz. 93.45, 93, 86.25, 57.8, 63.15, 25, 32.43, 99.95 and 86.3% reduction from the zero time value for BOD5, COD, TSS, PO4, SO4, NO3, NO2, turbidity and fecal coliforms respectively. Finally 48 hrs treated sample was passed through sand filter (SF) for further final polishing and approximately, 95.72, 95, 100, 73.5, 65.8, 58.3, 37.83, 100 and 91.5% reduction in BOD5, COD, TSS, PO4, SO4, NO3, NO2, turbidity and fecal coliforms was observed. This study showed that plastic media-trickling filter along with sand filter is a promising technology for wastewater treatment and can be scaled up for small communities in the developing countries.