Hisham A. Abbas

Antimicrobial Resistance Patterns of Proteus mirabilis isolates from Urinary tract, burn wound and Diabetic foot Infections

Proteus mirabilis is a common etiologic agent of urinary tract, burn wound and diabetic foot infections. Resistance to Proteus mirabilis is also common and represents a challenge to antibiotic therapy. This study aimed to investigate the antibiotic resistance of Proteus mirabilis isolated from three sources; urinary tract infections, burn wound infections in addition to diabetic foot infections. Forty-five clinical isolates of Proteus mirabilis (15 from each source) were used in this study. Complete resistance was found with each of ampicillin and tetracycline. High resistance was exhibited with cefepime. The resistance was intermediate against ceftazidime, cefotaxime, sulfamethoxazole-trimethoprim, amoxicillin-clavulinic, chloramphenicol, cefoperazone, aztreonam and ampicillin-sulbactam. Low resistance was found with piperacillin. These low resistance rates were also shown against tested aminoglycosides and fluoroquinolones. Very little resistance was found to imipenem, while no resistance was exhibited against piperacillin- tazobactam. The resistance pattern showed variation among different sources. Generally, burn wound isolates showed the highest resistance rates followed by diabetic foot isolates, while urinary tract isolates were the least resistant. High resistance was found with cefepime only in isolates from urinary tract infections and no diabetic foot isolate was highly resistant to any of the tested antibiotics. However, such resistance was observed with amoxicillin-clavulinic acid, cefepime, ceftazidime, cefotaxime and sulphamethoxazole-trimethoprim in burn wound isolates. Multidrug resistance (MDR) was also found with varying rates in isolates from different sources. MDR was more common in burn wound isolates than in diabetic foot isolates or urinary tract isolates. This study suggests that there is a variation in antibiotic resistance of Proteus mirabilis among different sources and alarms against high resistance especially in burn wound isolates that requires a strict policy in antibiotic dispensing to minimize such tesistance.

Resistance of Escherichia coli and Klebsiella pneumoniae isolated from different Sources to β-lactam Antibiotics

Escherichia coli and Klebsiella pneumoniae are important human pathogens that cause many infectious diseases. s-lactam antibiotics are commonly used in the treatment of these infections. However, resistance to such antibiotics complicates the treatment. Mechanisms of resistance to s-lactams include production of s-lactamases, efflux pumps, change in drug targets and outer membrane impermeability. This study was performed to investigate the resistance of Klebsiella pneumoniae and Escherichia coli to s-lactam antibiotics. The study was carried out from May 2014 to May 2015. Five hundred clinical isolates were collected from patients in Belquas Hospital and Mansoura University Hospitals. Three hundred isolates were identified as Klebsiella pneumoniae and Escherichia coli (one hundred and fifty isolates each). Klebsiella pneumoniae and Escherichia coli isolates showed high resistance to cefoperazone and ceftriaxone, intermediate resistance to cefoxitin, cefotaxime, ceftazidime and amoxicillin-clavulanic acid and low resistance to imipenem and meropenem. Klebsiella pneumoniae showed more resistance than Escherichia coli. Resistance of Klebsiella pneumoniae was higher to cefoperazone, ceftriaxone, ceftazidime, imipenem and meropenem. However, Escherichia coli was more resistant to cefotaxime and cefoxitin. The resistance to amoxicillin-clavulinic acid was more or less similar in both bacteria. In conclusion, the resistance of Klebsiella pneumoniae and Escherichia coli isolates to B-lactams was high and this needs a strict policy for antibiotic dispensing to reduce the emergence of resistance.

Diabetic Foot Infection

Diabetes is a worldwide disease. Diabetic foot infection is one of the most important complications of diabetes. It may lead to gangrene and amputation of the lower extremities. Peripheral neuropathy, peripheral arterial diseases in addition to immunosuppression contribute to the development of diabetic foot infection. Diabetic foot ulcers are classified according to the size of the ulcer in addition to its depth, site and appearance. Gram-positive cocci especially Staphylococcus aureus is the predominant bacterial pathogen that infect diabetic foot ulcer. However, Gram-negative bacteria and anaerobes are involved in chronic infections. The emergence of multidrug resistant bacteria and the formation of biofilms in diabetic foot ulcers complicate their treatment. Treatment of diabetic foot ulcer depends on medical and surgical intervention. Surgical removal of necrotic and unhealthy tissues, pressure offloading, revascularization and selection of proper wound dressing are important tools in the treatment of diabetic foot ulcers. For choice of the properantibiotic therapy, some factors must be taken into consideration such as the wound culture results, the severity of infection and the predominant bacteria. Staphylococcus aureus especially methicillin resistant Staphylococcus aureus, Gram-negative bacteria in most moderate and severe infections and obligate anaerobes in gangrenous foul smelling wounds should be targeted. Some adjunctive treatments may be helpful such as hyperbaric oxygen therapy, human skin equivalent and granulocyte-colony stimulating factor. Biofilms can be targeted by inhibition of adhesion, physical debridement, electrical stimulation of matrix penetration and quorum sensing inhibition.