This retrospective cohort study analyzed > 6-years data on patients with PLA from databases from two centers and found that performing blood cultures was associated with a low rate of carbapenem exposure in patients with PLA, especially in those with sepsis. The high blood culture positivity rate and the faster antibiotic degradation based on drug sensitivity results might play a role in explaining this correlation. To the best of our knowledge, this is the first study to evaluate the relationship between performing blood cultures and carbapenem exposure in patients with PLA. Some previous studies have reported the benefits of blood culture in many infectious diseases, although the results were slightly contradictory with the routine submission of blood cultures [6, 12, 13]. In this study, we summarized data from two emergency centers to help clinicians make decisions regarding the use of blood culture in the early stages of infection, in line with the current sepsis guidelines [4, 8]. current data support carbapenem-sparing options
The ESBL positivity rate of 8/110 (7.3%) observed in our study was lower than that reported in former studies [14]. We found majority of patients had more underlying diseases, recurrent episodes of infection, and broad-spectrum antibiotics exposure. PLA caused by ESBL-producing organisms from community-acquired infection is rare in China, which was consistent with the study by Lin et al. They also identified three specific genome regions in PLA strains; all PLA strains and non-invasive strains were ampicillin-resistant and cefotaxime susceptible, and none were ESBL producing. They also suggested that ESBLs are not associated with PLA [15]. Furthermore, in our study, mortality rates in patients without microbiological evidence of infection were similar to those in patients with microbiological evidence of infection, which was similar to the results of previous studies [16, 17]. Therefore, we believe that it is not necessary to prescribe carbapenems for PLA patients with or without sepsis.
Blood cultures play a critical role in sepsis management and should be recommended for patients with sepsis [4]. Obtaining blood cultures during antibiotic therapy is associated with a significant low pathogen detection rate. To maximize utility, at least two sets of blood cultures should be obtained before initiating antibiotic therapy [18], which is consistent with the recent data reported by Dellinger et al.[19].
In our study, the general baseline characteristics were almost similar in blood culture and unavailable blood culture groups; however, clinicians preferred to order blood cultures in PLA patients with diabetes mellitus, hepatobiliary benign diseases, or abdominal surgery history. These differences could be attributable to PLA patients with coexisting diseases having become more common in hospitals, particularly since previous researches have demonstrated that diabetes mellitus results in an increased risk of PLA [20, 21]. Li et al. performed blood cultures for 118 patients with PLA and found that patients with diabetes mellitus were significantly more likely to have a positive blood culture result [21]. Furthermore, there was a significant difference in the CRP levels, possibly indicating that the severity of infection was higher in the blood culture group than in the other group, suggesting that clinicians tended to identify pathogens in cases where infection was considered severe.
The global spread of ESBLs has led to a significant increase in exposure of patients to carbapenems. Moreover, carbapenems are usually used as front-line drugs for gram-negative bacterial infections because of progressive resistance among other ESBLs. However, as documented in large surveillance studies, carbapenem resistance has been increasing [22]. Furthermore, there are significant variations in the usage of antibiotics and the ordering of blood cultures between hospitals and clinicians. Our work has contributed to the understanding of the relationship between performing blood cultures and carbapenem exposure. Multiple regression analysis was used to adjust many confounding factors and stratify patients with or without sepsis. Our study suggests that performing more blood cultures are associated with less exposure to carbapenems, which may help improve drug resistance.
However, our study has some limitations. First, the study was retrospective in nature, and procedures related to performing blood cultures with carbapenem administration were not standardized. However, this reflects the current real-world practice, especially in many developing countries, such as China. Second, carbapenem exposure is not well defined in the guidelines, and our results might have been affected by the culture time. Third, despite careful adjustment for several confounding factors, unmeasured confounders could have biased our results and the subsequent conclusions. Finally, strong conclusions cannot be made because the sample size was small and the results reported in two emergency medical centers in Shanghai cannot be extrapolated to other populations with different epidemiological or clinical settings.