3.2. Temporal Correlation Dynamics Between Aminoglycoside Consumption and Resistance Indices
In the next phase of our study, we examined the detailed correlation between aminoglycoside consumption and ARI data for
A. baumannii. Consumption of amikacin and its ARI had a Pearson correlation value (r) of 0.29, showing a slight positive association (
Figure 2A). On the other hand, tobramycin correlation between the consumption and its ARI showed a correlation coefficient of -0.16, indicating a weak negative correlation (
Figure 2B). The use of gentamicin was more negatively correlated with ARI, as shown by a correlation value of -0.42 (
Figure 2C). These findings demonstrate a mild correlation between amikacin consumption and the development of resistance in
A. baumannii. Tobramycin and gentamicin exhibit different patterns in this regard.
Notable associations were also observed during the analysis of the use of aminoglycosides and ARI data for
K. pneumoniae. The correlation between amikacin use and its ARI is represented by a Pearson correlation coefficient of 0.39, which indicates a moderate positive correlation (
Figure 3A). On the other hand, the relationship between the amount of tobramycin consumed and its associated ARI shows a correlation coefficient of -0.42, suggesting a moderate negative association (
Figure 3B). The intake of gentamicin is weakly negatively correlated with ARI, as shown by a Pearson correlation value of -0.25 (
Figure 3C). The results indicate a clear link between the use of aminoglycosides and the development of resistance in
K. pneumoniae. Amikacin shows a moderate positive correlation, while tobramycin and gentamicin have negative associations.
In the subsequent stage of the investigation, we analyzed the correlation between the consumption and ARI of aminoglycosides in
A. baumannii with a one-year delay, to explore the delayed impact of antibiotic use on the development of resistance. Consumption of amikacin and its ARI exhibited a Pearson correlation value (r) of 0.27, demonstrating a slight positive association (
Figure 4A). This indicates that there is a correlation between increased use of amikacin in the previous year and an increase in resistance in the upcoming one. However, the relationship between the amount of tobramycin consumed and its ARI showed a Pearson correlation value of -0.23, suggesting a mild negative connection (
Figure 4B). The intake of gentamicin was somewhat negatively correlated with ARI, as shown by a correlation value of -0.42 (
Figure 4C). The data presented indicate that there is a variable relationship between aminoglycoside consumption and the emergence of resistance in
A. baumannii. Amikacin shows a slight positive association, while tobramycin and gentamicin show negative correlations, highlighting the delayed effect of these antibiotics.
Interesting associations were observed when we analyzed the consumption of aminoglycosides and ARI for
K. pneumoniae with a one-year delay. The association between amikacin consumption and its ARI was represented by a Pearson correlation coefficient of 0.29, showing a modest positive correlation (
Figure 5A). This indicates that a greater amount of amikacin used in the previous year is associated with a rise in resistance in
K. pneumoniae. On the other hand, the relationship between the amount of tobramycin consumed and its ARI showed a Pearson correlation value of -0.42, which indicates a mild negative association (
Figure 5B). The intake of gentamicin is somewhat negatively correlated with ARI, as shown by a correlation value of -0.25 (
Figure 5C). These results demonstrate that there is a fluctuating relationship between aminoglycoside intake and the development of resistance in
K. pneumoniae. Specifically, amikacin in this species also exhibits a mild positive connection, while tobramycin and gentamicin show negative correlations. This again highlights the delayed effects of antibiotic consumption on the development of resistance.
In the following phase of our investigation, we analyzed the ARI of meropenem, as meropenem resistance is a reliable indicator of multidrug resistance for both bacterial species, in the context of aminoglycoside resistance. Examination of aminoglycoside ARIs revealed that the values for tobramycin, gentamicin, and amikacin were consistently high, with values near 1.0 (
Figure 6). However, significant fluctuations were also observed for tobramycin and gentamicin. On the ARI other hand, the meropenem also exhibited notable oscillations, suggesting that there were changes in the levels of multidrug resistance over time. These results suggest an intricate interaction between aminoglycoside and meropenem resistance.
To gain a clearer understanding of this complex relationship, we also examined the correlation of ARI values of each aminoglycoside and meropenem in A. baumannii.
The relationship between amikacin ARI and meropenem ARI is characterized by a correlation coefficient of 0.18, suggesting a modest positive connection (
Figure 7A). The link between the ARI of tobramycin and meropenem was characterized by a Pearson correlation value of 0.08, showing a very modest positive correlation (
Figure 7B). The Pearson
r value between the ARI of gentamicin and meropenem is -0.01, showing a very weak negative association (
Figure 7C). These findings indicate that while amikacin shows a modest positive correlation with meropenem ARI, tobramycin and gentamicin exhibit minimal associations, suggesting a complex and varied relationship between aminoglycoside resistance and multidrug resistance in
A. baumannii.
Examining ARI of different aminoglycosides and the multidrug resistance indicator meropenem reveals different trends in the case of
K. pneumoniae (
Figure 8). ARIs for tobramycin, gentamicin, and amikacin exhibited high variability, with values shifting considerably throughout the measured time frame. On the contrary, the meropenem ARI has lower overall values compared to the aminoglycosides and demonstrates less variability, indicating a somewhat constant but lower degree of multidrug resistance during the investigated time. Thus, meropenem ARI demonstrated multidrug resistance at a lower level in
K. pneumoniae, serving as a strong contrast to the more prevalent multidrug-resistant
A. baumannii.
Examination of the Pearson correlation between the antibiotic resistance indices of these aminoglycosides and meropenem demonstrated clear and separate associations. The association between amikacin ARI and meropenem ARI is characterized by a Pearson correlation coefficient of -0.08, suggesting a very weak negative correlation (
Figure 9A). The link between tobramycin and meropenem was shown by a Pearson correlation coefficient of -0.01, suggesting a very weak negative correlation (
Figure 9B). The correlation coefficient between gentamicin and the meropenem ARI is 0.03, showing a very weak positive link (
Figure 9C). These findings indicate that the associations between aminoglycoside ARIs and meropenem ARI in
K. pneumoniae are minimal, with tobramycin and amikacin showing very weak negative correlations and gentamicin showing a very weak positive correlation, highlighting the complexity of resistance mechanisms in this species.
To better understand this complex scenario, in the next part of our work, we compared the consumption data of each aminoglycoside separately for the two species with the meropenem ARI. According to the statistics, the use of amikacin differs significantly and remains higher than other aminoglycosides on average (
Figure 10). Consumption experiences substantial fluctuations during the period under investigation. However, gentamicin and tobramycin show more stable and decreased patterns of use. In addition, the ARI of the meropenem for
A. baumannii exhibits a fluctuating but increasing pattern of resistance over the years.
In order to ascertain if the use of certain aminoglycosides is associated with the occurrence of multidrug resistance, we conducted a separate analysis of the consumption data for each individual aminoglycoside in connection to the meropenem ARI data. The yearly intake of amikacin and meropenem ARI for
A. baumannii exhibited a Pearson correlation coefficient of 0.2, showing a slight positive link (
Figure 11A). This indicates that there is a correlation between increased yearly use of amikacin and increased resistance to multidrug. The annual intake of tobramycin has a very modest negative connection with ARI of the meropenem, as shown by a Pearson correlation coefficient of -0.04 (
Figure 11B). These findings suggest that increased yearly tobramycin use is not correlate with multidrug resistance in
A. baumannii. However, the relationship between the amount of gentamicin used each year and the appearance of meropenem antibiotic resistance reveals a Pearson correlation value of -0.32, showing a moderate negative connection (
Figure 11C). These findings together imply that amikacin exhibits a weak positive connection, tobramycin exhibits a weak negative correlation, and gentamicin exhibits a substantial negative correlation with multidrug resistance indicator meropenem ARI.
In the next part of our work, we compared the consumption data of each aminoglycoside with the meropenem ARI for
K. pneumoniae (
Figure 12). The ARI of meropenem exhibited a fluctuating low pattern of resistance over the years, indicating variable decreased levels of multidrug resistance.
Examination of the Pearson connection between yearly aminoglycoside intake and meropenem ARI, which signifies multidrug resistance, for
K. pneumoniae demonstrated interesting associations. The yearly consumption of amikacin and the meropenem ARI exhibited a Pearson correlation coefficient of -0.28, showing a slight negative link (
Figure 13A). The yearly intake of tobramycin had a very modest positive link to ARI meropenem, as shown by a correlation coefficient of 0.09 (
Figure 13B). On the other hand, the relationship between the amount of gentamicin used each year and the occurrence of resistance to antibiotics with meropenem was highly correlated, as shown by a Pearson correlation coefficient of 0.70, suggesting a significant positive association (
Figure 13C). This is a considerable correlation between increasing yearly gentamicin intake and growth in multidrug resistance.
During the last stage of our project, we analyzed the ARI of meropenem with a one-year time delay compared to aminoglycoside consumption. This allowed us to evaluate the possible delayed impacts of aminoglycoside usage alterations on multidrug resistance. A weak positive association, indicated by the Pearson correlation coefficient of 0.33, was found between the annual consumption of amikacin and meropenem ARI for
A. baumannii (
Figure 14A). The relationship between the annual consumption of tobramycin and ARI of meropenem next year showed a very weak positive association, with a Pearson correlation value of 0.11 (
Figure 14B). On the other hand, a weak negative association was detected with a correlation coefficient of -0.30 between the annual intake of gentamicin and ARI meropenem in the following year. The results indicate that the intake of amikacin and tobramycin has a slight delayed inducing effect on multidrug resistance in
A. baumannii. On the other hand, the usage of gentamicin is linked to a weak delayed decrease in multidrug resistance.
A weak negative association, as indicated by the Pearson correlation coefficient of -0.28, was found between the annual consumption of amikacin and the ARI of meropenem in the case of
K. pneumoniae (
Figure 15A). Annual consumption of tobramycin had a very modest positive link with meropenem ARI, as indicated by a correlation coefficient of 0.09 (
Figure 15B). On the other hand, the relationship between the amount of gentamicin used each year and the occurrence of resistance to meropenem in the next year was highly correlated, with a Pearson correlation value of 0.70, showing a strong positive association (
Figure 15C). This is a robust correlation between increasing annual gentamicin intake and an increase in multidrug resistance, as seen by meropenem ARI with a one-year delay.