Oxacillin Resistant Staphylococcus aureus from Diverse Sources in Nnewi Nigeria: Susceptibility to Vancomycin, Linezolid, Teicoplanin and Medicinal Plant extracts

Background:  Methicillin (Oxacillin)-resistant S. aureus (MRSA or ORSA) remains a major public health concern. This concern has raised the need to continually monitor the susceptibility profile of local MRSA isolates to standard anti-MRSA therapeutic agents. Objective: To isolate MRSA from diverse sources in our locality and to determine their susceptibility to Vancomycin, Linezolid, Teicoplanin, and to extracts of Parkia biglobosa and Vanda roxburgii – medicinal plants commonly used in the treatment of wound sepsis in our locality.  Method: A total of 34 raw meat samples were randomly collected from butchers in Nnewi main market. Other samples collected included: water samples from the market supplies, nasal swabs from 15 butchers, nasal and oral swabs from 8 pet dogs, and surface swab from ten local currency notes. The samples were screened for ORSA. Inhibitory concentrations of Oxacillin to isolates were compared with those of other anti-MRSA agents and to medicinal plants extracts. Results: Results showed that 27 (79%) of meat samples yielded ORSA. The recovery rates of ORSA from other samples were as follows: pet dogs 7(88%), butchers 4 (27%), local currency notes 4(40%), and water supplies 1(50%). Thirteen (34%) of ORSA were of a classic phenotype (MIC ≥ 16 µg/ml). Linezolid MIC ranged from 0.015 – 4µg/ml, while Vancomycin ranged from 0.06 – 4µg/ml. All isolates (100%) were susceptible to teicoplanin. The MIC of the medicinal plant extracts ranged from 0.098 – 6.25mg/ml. Conclusion: Results suggests that plants could be a valuable source of anti-MRSA drugs and that, pet animals, currency notes, and raw meat, could expose to risk of acquiring ORSA

The effect of povidone–iodine on normal bacteria conjunctival flora in adult patients in Onitsha Nigeria

Objectives: To determine the normal conjunctival flora and the effect of povidone–iodine on the flora in adult patients at the Guinness Eye Centre Onitsha Nigeria.Materials and Methods: Each randomly recruited new adult patient had conjunctival swab taken from one eye; then a drop of 5% povidone–iodine solution was instilled on the conjunctiva. Conjunctival swabs were taken at 1, 5, and 10 min after povidone–iodine instillation. The swabs were smeared on glass slides and also inoculated unto MacConkey, chocolate, and nutrient agar. Microbial study of the specimens was undertaken.Results: Of the 250 eyes of the 250 patients, 164 (65.6%) were culture-positive. A total of 225 organisms were isolated from the 164 culture-positive specimens as follows: Pseudomonas aeruginosa was isolated in 142 (63.1%), Staphylococcus epidermidis in 79 (35.1%), and Staphylococcus aureus in four (1.8%). Among the 61 specimens that grew more than one organism, 59 (96.7%) had a mixed growth of P. aeruginosa and S. epidermidis and 2 (3.3%) grew both S. epidermidis and S. aureus. Povidone–iodine significantly reduced the mean bacterial colony count in all bacterial isolates 10 min after instillation, that is: 114.4 to 35.7 for P. aeruginosa (P< 0.05), 71.7 to 15.8 for S. epidermidis (P< 0.05), and 45.5 to 3.0 for S. aureus (P<0.05). Bacterial colonies persisted in seven (2.8%) eyes 10 min after instillation of 5% povidone–iodine.Conclusion: The normal conjunctiva of some patients harbor virulent bacteria, which load 5% povidone–iodine greatly reduced. These facts should be taken into consideration when planning intraocular surgery as part of the efforts to prevent endophthalmitis.Keywords: Conjunctival bacteria flora, Nigeria, povidone–iodin