Exploring trends in antibiotic use and resistance in a district, regional and tertiary hospital in the uMgungundlovu District.

Abstract

Antibiotics play an important role in overcoming life-threatening bacterial infections. However, the increasing rate of antibiotic resistance is a serious threat to public health. Undoubtedly the indiscriminate use of antibiotics plays a role in the emergence of resistance. The objective of this study was to identify the trends in antibiotic use and resistance at three public sector hospitals at three different levels of healthcare in the uMgungundlovu district, i.e., a district hospital, a regional hospital and a tertiary hospital. The antibiotics indicated for the treatment of infections caused by Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria) were investigated. Yearly antibiotic consumption data was calculated as Defined Daily Dose (DDD) per 1 000 inhabitants and percentage susceptibility was analysed based on susceptible and non-susceptible isolates for each antibiotic. There was a general trend of reduced antibiotic susceptibility as the levels of healthcare increased attributed to the fact that more severe and complex infections are treated at the higher levels of healthcare and require greater quantities of and/or broader spectrum antibiotics. For treatment of infections caused by S. aureus antibiotic use generally increased as the level of healthcare increased. Azithromycin was the most frequently used while linezolid was the least used antibiotic and showed the highest levels of susceptibility across all levels of healthcare. S. aureus showed the lowest level of susceptibility to cloxacillin across all the levels of healthcare and was indicative of the prevalence of methicillin-resistant S. aureus (MRSA). When antibiotic use was correlated with resistance, cloxacillin displayed a downward trend in use from 2014 to 2016 while cloxacillin resistance increased from 2014 to 2015 followed by a decrease in resistance in 2016 indicating that resistance is a function of time and use and that the lag time between the decrease in use and a corresponding decrease in resistance is not predictable and varies for different antibiotics in different healthcare settings. In contrast, azithromycin showed a steady decline in resistance although use increased over the three years (2014-2016). In the case of the treatment of infections caused by E. coli there was a general trend of the greater use of narrow spectrum antibiotics at the lower district and regional levels while the broad-spectrum antibiotics were used more frequently at a tertiary level. Trimethoprim-sulphamethoxazole was used the most, whereas colistin was used the least. Contrary to expectations, there were higher susceptibility levels to third and fourth generation cephalosporins and meropenem at a tertiary level than regional level. E. coli showed lowest levels of susceptibility to ampicillin and highest level of susceptibility to levofloxacin across all levels of healthcare. When antibiotic use was correlated with resistance, antibiotics that were used frequently however resistance remained high. The same trend was observed with amoxicillin clavulanic acid and ampicillin use and resistance indicating possible co-selection of resistance by the use of other classes of antibiotics. This study added to the body of knowledge that there exists a link between the use of antibiotics and resistance, albeit not a direct causal one. Quantifying antibiotic use and identifying trends in resistance associated with antibiotic consumption assists prescribers and policy makers to improve antibiotic use, guide antibiotic stewardship programmes and optimise antibiotic policies and guidelines.(sulphamethoxazole-trimethoprim, amoxicillin clavulanic acid and ampicillin) displayed high levels of resistance over the three years. Trimethoprim-sulphamethoxazole use decreased slightly over the years however resistance remained high. The same trend was observed with amoxicillin clavulanic acid and ampicillin use and resistance indicating possible co-selection of resistance by the use of other classes of antibiotics. This study added to the body of knowledge that there exists a link between the use of antibiotics and resistance, albeit not a direct causal one. Quantifying antibiotic use and identifying trends in resistance associated with antibiotic consumption assists prescribers and policy makers to improve antibiotic use, guide antibiotic stewardship programmes and optimise antibiotic policies and guidelines.