Antimicrobial resistance is a global challenge requiring reliable surveillance data collection and use. Prior studies on resistance in Zambia depended on laboratory methods with limited standardization. Since 2015, the University Teaching Hospital (UTH) microbiology laboratory has used the Vitek 2 Compact (bioMerieux, Inc., Marcy-l’Étoile, France) for standardized identification and susceptibility testing. We conducted a cross-sectional study of 2019 bacterial isolates collected from July 2015 to April 2017 to identify bacterial causes of infections, their susceptibility to commonly used antibiotics at UTH, and develop hospital antibiograms with a multidisciplinary team using World Health Organization guidance. We found high levels of antibiotic resistance among Gram negative bacteria. Escherichia coli and Klebsiella pneumoniae were highly resistant to all antibiotics except amikacin and carbapenems. E. coli had susceptibilities of 42.4% to amoxicillin/clavulanic acid, 41.4% to ceftriaxone, 40.2% to ciprofloxacin, and 10.4% to trimethoprim/sulfamethoxazole (TMP/SMX). K. pneumoniae had susceptibilities of 20.7% to amoxicillin/clavulanic acid, 15.6% to ceftriaxone, 48.5% to ciprofloxacin, and 12.3% to TMP/SMX. The high resistance to 3rd generation cephalosporins indicates high rates of beta-lactamase production. This is information that clinicians need to inform clinical decision making and choice of empiric antibiotics and that UTH requires to inform antimicrobial stewardship such as improvements in antibiotic use.

BackgroundAntibiotic resistance is a worldwide problem. Prior studies on patterns of resistance in Zambia depended on laboratory methods that lacked standardization. UTH is a 1,655-bed quaternary care hospital and the primary teaching hospital of Zambia. Since 2015, the microbiology laboratory has used Vitek 2 Compact (bioMerieux, Inc., France) for standardized detection of resistance.MethodsWe conducted a retrospective cross-sectional study of data collected on bacterial isolates analyzed from July 2015 to April 2017. We entered the data into WHONET 5.6 and aggregated it to develop hospital antibiograms. Due to high levels of resistance, we defined susceptible, intermediate, and resistant as >70%, 40–70%, and <40% of isolates sensitive to a drug, respectively. To improve usability, a version replacing the percent susceptible with these categories was developed.ResultsWe analyzed 2,019 isolates to identify susceptibility patterns to commonly used antibiotics at UTH. Escherichia coli and Klebsiella pneumoniae, the most commonly isolated Gram-negative (GN) organisms, were resistant to most drugs including ceftriaxone, indicating high rates of extended-spectrum β-lactamase production. Methicillin-resistant Staphylococcus aureus (MRSA) made up 37% of S. aureus isolates. MRSA and methicillin-susceptible S. aureus were resistant to trimethoprim/sulfamethoxazole, a commonly used drug at UTH. S. pneumoniae was resistant to most drugs against which it was tested.ConclusionMDROs were common at UTH with carbapenems indicated for empiric GN therapy. Further research should assess the extent and depth of antibiotic resistance in Zambia. Antibiograms provide critical information for clinicians to strategically use antibiotics.ReferencesCarroll M, Rangaiahagari A, Musabeyezu E, et al. Five-year antimicrobial susceptibility trends among bacterial isolates from a tertiary health-care facility in Kigali, Rwanda. Am J Trop Med Hyg. 2016;95(6):1277–83.Moremi N, Claus H, Mshana SE. Antimicrobial resistance pattern: a report of microbiological cultures at a tertiary hospital in Tanzania. BMC Infect Dis. 2016;16(1):756.Kumburu HH, Sonda T, Mmbaga BT, et al. Patterns of infections, aetiological agents and antimicrobial resistance at a tertiary care hospital in northern Tanzania. TM and IH. 2017;22(4):454–64. Disclosures E. Heil, ALK-Abelló: Grant Investigator, Research grant. L. Hachaambwa, Centers for Disease Control and Prevention (CDC): Cooperative Agreement to Institution, Financial support for the work described in this abstract was made possible by a cooperative agreement award from the Centers for Disease Control and Prevention (CDC) to the University of Zambia and to the University of Maryland School of Medicine. J. K. Johnson, Q-Linea: Investigator, Research grant. Applied Biocode: Investigator, Research grant.