ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF CEFTAZIDIME-AVIBACTAM AMONG DIFFERENT CLINICAL SPECIMENS AGAINST ESCHERICHIA COLI AND KLEBSIELLA PNEUMONIAE

Abstract

As defined by WHO, ―Antibiotic resistance is a phenomenon that occurs when bacteria is not able to produce response to the use of particular medicine or medicines‖. Resistance to antibiotics leads to increased cost of health care, increased morbidity and mortality. There is a need to address the issue of conventional antibiotic resistance by focusing on the pattern of prescription and use of antibiotics. Bacteria achieve antibiotic resistance in various ways; one of the patterns followed by bacteria is by producing enzymes that protect the bacterium. Antimicrobial resistance among members of Enterobacteriaceae is increasing and therapeutic options remain insufficient to treat these infections. The bacteria is resistant to drugs by limiting their uptake, modified its target, inactivate the drug, and stimulate active efflux of a drug. These pathways may be native to the bacteria or acquire from other pathogens. Ceftazidime-avibactam is the combination of drugs effective against all of the resistant isolate of Enterobacteriaceae. Ceftazidime-avibactam is prescribed for the treatment of complicated intra-abdominal infections complicated urinary tract infections, hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). South-Asia is known as a hub for multidrug-resistant (MDR) bacteria. Unfortunately, proper surveillance and documentation of MDR pathogens are lacking in Pakistan. The objectives of the study were to identify the susceptibility of Ceftazidime-avibactam against Escherichia coli and Klebsiella pneumonia and their frequency in different clinical specimens. The study design was cross-sectional study. The samples were collected from patients at PNS Shifa Hospital Karachi. The sample size was 150. The age group of individuals ranged from 10-50 years. Ethical permission was taken from hospital review committee. Informed consent for the study was taken from the patients. The data collection form was designed to record the demographic data of patients. The specimens received in lab were inoculated on Blood and MacConkey’s agar culture plates. The culture plate was inoculated at 37 ℃ in incubator for 24 to 48 hours. Identification of Enterobacteriaceae was done by colony morphology, gram staining, biochemical tests, and API 20E. After identification, the susceptibility profile of conventional antibiotics was identified against both pathogens. Next, Mueller Hinton agar was used to check the antibiotic xi susceptibility of Ceftazidime-avibactam by disk diffusion method and confirmed by E-Test. Ceftazidime-avibactam shows sensitivity against 82.7% of the isolates while 17.3 % isolates were resistant. The minimum inhibitory concentration of microorganisms is measured by E-test method that revealed most of the isolate show sensitivity less than 1 μg/mL concentration whereas few of them showed susceptibility on 2-8 μg/mL concentration, while very limited organisms showed resistance against Ceftazidime-avibactam. We compared our results with other classes of antibiotics used commonly on the samples of Klebsiella pneumonia and Escherichia coli in microbiology laboratory PNS Shifa hospital Karachi. This gives an insight for improved treatment methodologies for future prospects particularly diseases caused by members of Enterobacteriaceae. It was concluded that Ceftazidime-avibactam is a novel drug combination that shows high sensitivity against Klebsiella pneumoniae and Escherichia coli. Our study results revealed that Ceftazidime-avibactam is more effective on Escherichia coli as compare to Klebsiella pneumoniae. Ceftazidime/avibactam, therefore, presents as an additional treatment option against the multidrug-resistant gram-negative bacteria. It is worth mentioning, no other antibiotic tested has come up with better overall coverage than Ceftazidime-avibactam against resistant Escherichia coli and Klebsiella pneumonia.