Ceftriaxone- and ceftazidime-resistant Klebsiella species, Escherichia coli, and methicillin-resistant Staphylococcus aureus dominate caesarean surgical site infections at Mulago Hospital, Kampala, Uganda

Abstract

Objectives: The aim of this study was to determine the proportion and mechanism of resistance to ceftriaxone and ceftazidime among Klebsiella species and Escherichia coli and examine the burden of methicillin-resistant Staphylococcus aureus from caesarean section surgical site infections in Uganda. Methods: Wound swabs from 109 caesarean section surgical site infections were cultured for pathogenic bacteria following standard microbiological procedures. The Kirby–Bauer disc diffusion technique was used for antimicrobial susceptibility testing. Methicillin-resistant S. aureus diagnosis was based on polymerase chain reaction testing for the mecA gene. Data were analysed using SPSS-IBM Statistics v.20. Results: A total of 118 pathogens were recovered from 93 (85%) of 109 surgical site infections swabs. Of the 118 pathogens, gram-negative bacteria were 69 (58.5%), including 44 (37.3%) Klebsiella species, 11 (9.3%) E. coli, 6 (5.1%) Citrobacter species, and 8 (6.8%) other gram-negative bacteria. In total, 49 of the 118 pathogens were gram-positive bacteria, including 34 (28.8%) S. aureus and 15 (12.7%) Enterococci species. Resistance to ceftriaxone was detected in all 11 (100%) of the E. coli and in 43 (97.7%) of the 44 Klebsiella species and to ceftazidime in all 11 (100%) of the E. coli and 40 (91%) of the 44 Klebsiella species. Extended-spectrum beta-lactamase explained resistance to ceftazidime in 10 (91%) of the 11 E. coli and 19 (48%) of the 40 Klebsiella species. Carbapenemase production explained 15 (38%) of the 40 ceftazidime-resistant Klebsiella species. Methicillin-resistant S. aureus was detected in 91% of S. aureus. Conclusion: Klebsiella species, E. coli, and S. aureus–majority methicillin-resistant S. aureus dominated the pathogens in caesarean section surgical site infections. Almost all of the E. coli and Klebsiella species were resistant to ceftriaxone or ceftazidime. Extended-spectrum beta-lactamase was the underlying resistance mechanism among almost all of the ceftriaxone- or ceftazidime-resistant E. coli. However, this mechanism accounted for less than half of ceftriaxone- or ceftazidime-resistant Klebsiella species, where carbapenemases accounted for 40% of the resistance, a finding previously unreported in Uganda.