1. Introduction
One of the most important health problems currently is antimicrobial resistance [1] . The emergence of the COVID-19 pandemic could seriously impact the development of antibiotic resistance worldwide. Antibiotic use has further increased in the time of COVID-19 pandemic. Many COVID-19 treatment guidelines have incorporated antibiotic prophylaxis to prevent bacterial co-infections in hospitalized COVID-19 patients [1] . In the midst of chaotic COVID-19 pandemic, the inappropriate use of antibiotic and the lack of attention to surveillance could worsen the situation of antimicrobial resistance [2] [3] . The increased prevalence of resistant bacterial infections such as methicillin-resistant Staphylococcus aureus (MRSA) in the previous severe acute respiratory syndrome (SARS) epidemic in 2003 was an example that situation could deteriorate further due to healthcare-associated infections by multidrug-resistant microorganisms [1] . A review stated that every year more than two million infections associated with antimicrobial resistance, causing 29,000 deaths occur in the United States, with costs more than 4.7 billion US Dollars [3] .
The ESKAPE pathogens consisting of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa and Enterobacter spp. were designated as priority status by World Health Organization in 2017 as these organisms has the capability to escape the bactericidal action of antibiotics [4] . The ESKAPE pathogens are major etiology of healthcare-associated infections around the world, which cause serious and usually fatal human infections [3] . The data before and after COVID-19 pandemic are necessary to assess the impact of the pandemic on antimicrobial resistance [1] . This study aims to describe the rates of bloodstream infection due to ESKAPE pathogens and their resistance pattern in Siloam Hospital Karawaci, the teaching hospital for Faculty of Medicine, Pelita Harapan University before and after COVID-19 pandemic, from the year 2019 to 2022.
2. Materials and Methods
2.1. Design and Setting
The descriptive, retrospective, longitudinal study assesses the rates of bloodstream infection due to ESKAPE pathogens and their resistance pattern. Samples were collected from blood of patients admitted in Siloam Hospital Karawaci, Banten Province, Indonesia, from the January 1st, 2019 until December 31st, 2022. This is the teaching hospital for Faculty of Medicine, Pelita Harapan University. This hospital did not care for COVID-19 patients during the pandemic. Bacterial cultures and antibiotic resistance were performed using an automated VITEK® system (Bio-Mérieux) [5] . Resistance to antibiotics was evaluated based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standard Institute (CLSI) and the definition of multidrug resistance (MDR) was according to the European Centre for Disease Prevention and Control (ECDC). MDR bacteria are bacteria with resistance to more than 1 antibiotics in more than 3 different classes [6] .
2.2. Data Analysis
The data of antibiotic susceptibility tests were collected to determine the absolute number of resistant and its rate out of the total number of tests performed on the species in that year. Analysis and plot of the result were created using Microsoft Excel 2016 software (Microsoft Corp., Redmond, WA, USA).
3. Results
3.1. Bacterial Species According to Calendar Years
Out of the 296 ESKAPE pathogens from blood samples obtained, S. aureus was the most frequent species (37.8%), followed by K. pneumoniae (31.4%), A. baumannii (13.9%), P. aeruginosa (8.8%), Enterobacter spp. (5.1%), and E. faecium (3.0%). In 2019 and 2022 S. aureus was the most frequent species (45.6% and 45.7%), and in 2020 and 2021 K. pneumoniae was the most frequent species (36.4% and 30.0%), while least frequent species in 2019, 2020, 2022 was E. faecium (1.9%, 2.6%, 0.0%) and in 2021 was Enterobacter spp. (4.3%) (Figure 1).
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Figure 1. Distribution of ESKAPE pathogens from 2019-2022.
3.2. Resistance Patterns per Pathogen According to Calendar Years
In the case of E. faecium, the resistance rates against penicillin-beta lactamase inhibitor, aminoglycoside, and trimethoprim sulfamethoxazole were high and increased from 2019 until 2021 (50.0% - 80.0%). The resistance rates against quinolone were also high but they increased from 2019 (50.0%) to 2020 (100.0%), then decreased in 2021 (80.0%). The resistance rates against nitrofurantoin and tigecycline were 0.0% from 2019 to 2021. The vancomycin resistance was only noted in 2020 (50.0%). In 2022, no sample of E. faecium was found (Figure 2(a)).
For Staphylococcus aureus, the resistance rates against penicillin-beta lactamase inhibitor, 3rd generation cephalosporin, quinolone, aminoglycoside, trimethoprim sulfamethoxazole, fosfomycin decreased from 2019 (12.8% - 3.4%) until 2021 (0.0%) and then increased again in 2022 although lower than 2019 (9.5% - 14.3%). The resistance rates of MRSA were similar against penicillin-beta lactamase inhibitor during the four-year study. As for imipenem and meropenem, the highest resistance rates occurred in 2021, and the lowest were in 2022. Resistance against ertapenem was the highest although the rates decreased from 2020 until 2022 (68.0% - 28.6%). For tigecycline the resistance rates quite similar throughout 2019 until 2022 4.0% - 6.0%) (Figure 2(b)).
The resistance rates for K. pneumoniae against penicillin-beta lactamase inhibitor, 3rd generation cephalosporin, quinolone, aminoglycoside, trimethoprim sulfamethoxazole, meropenem and ertapenem peaked from 2019 to 2020, then decreased in 2021 and reached the lowest in 2022. Resistance against imipenem and tigecycline were quite similar throughout 2019 until 2022 (3.6% - 5.6% and 9.5% - 15.4%). Resistance against fosfomycin decreased from 2019 until 2022 (15.4% - 0.0%) (Figure 2(c)).
Resistance pattern of A. baumanii was not favorable for most antimicrobials from 2019 until 2021, as the rates were above 50.0%, with the exception of tigecycline. The resistance rates peaked from 2019 to 2020, then decreased in 2021, and reached 0.0% in 2022 in most antimicrobials. Resistance rates against ertapenem were decreasing from 2019 until 2022, but it was still high (50.0%) (Figure 2(d)).
In the case of P. aeruginosa, the resistance pattern was quite variable. The resistance rates against piperacillin/tazobactam increased from 2019 to 2020 and then decreased to 0.0% in 2021 and 2022. The resistance rates against ceftriaxone could only reach 50.0% in 2021, but they were very high in other year (88.9% - 100.0%). The resistance rates against aminoglycoside and quinolone decreased from 2019 until 2021 and reaching as low as 0.0% in 2022. The resistance against imipenem and meropenem decreased from 2019 until 2022, reaching as low as 0.0%. On the other hand, the resistance against ertapenem was increased from 2019 until 2022, reaching 100.0%. Against tigecycline, the resistance rates were even worrying, reaching 100.0% except in 2020 (88.9%) (Figure 2(e)).
Resistance pattern of Enterobacter spp. against ampicillin sulbactam increased from 75.0% in 2019, reaching 100.0% in 2020 until 2022. Against ceftazidime the rates increased dramatically from 2019 to 2020 (0.0% to 60.0%), reaching to 66.7% in 2021 and 2022. Against ceftriaxone and trimethoprim sulfamethoxazole, the rates also increased dramatically from 2019 to 2020, then decreased in 2021 and 2022. The resistance against ciprofloxacin increased from 2020 and 2021, then decreased in 2022. The resistance against levofloxacin, amikacin, meropenem, and fosfomycin were 0.0% in the four-year study (Figure 2(f)).
3.3. Multidrug Resistance Patterns per Pathogen According to Calendar Years
S. aureus and K. pneumoniae showed similar pattern as the MDR rates decreased from 2019 until 2021 and then increased again in 2022, although the rate in 2022 did not exceed the rate in 2019. A. baumanii showed substantial decrease in rate of MDR from 2019 until 2022, while P. aeruginosa had similar rate of MDR in 2019 and 2020, and then decreased substantially in 2021 and 2022. E. faecium and Enterobacter spp. showed great variability of MDR rate throughout 2019 until 2022 (Figure 3).
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Figure 3. Pattern of multidrug resistance of each ESKAPE pathogens from 2019-2022.
4. Discussion
Caglione et al. in a study on ESKAPE pathogens in Italy from 2015 to 2019 found that K. pneumoniae was the most frequent species (31.1%), followed by P. aeruginosa (19.8%), S. aureus (18.6%), Enterobacter spp. (13.4%), A. baumannii (13.2%), and E. faecium (3.8%) [7] . El-Kady et al. in a study in Saudi Arabia from January 2019 to December 2020 found that K. pneumoniae was the most frequent species (47.4%), followed by P. aeruginosa (29.2%), Enterobacter spp. (14.0%), and A. baumannii (9.4%) [8] . Azimi et al. in a study from May 2016 to March 2017 found that A. baumannii was the most frequent species (44%), followed by S. aureus (39%), E. coli (30%), K. pneumoniae (32%), Enterococcus spp. (22%), Enterobacter spp. (21%), and P. aeruginosa (20%) [9] . The results of this study were different, as that S. aureus was the most frequent species (37.8%), followed by K. pneumoniae (31.4%), A. baumannii (13.9%), P. aeruginosa (8.8%), Enterobacter spp. (5.1%), and E. faecium (3.0%). In 2019 and 2022 S. aureus was the most frequent species (45.6% and 45.7%), but in 2020 and 2021 K. pneumoniae was the most frequent species (36.4% and 30.0%). Although the results between these studies were different, by S. aureus and K. pneumoniae were the dominant species among ESKAPE pathogens before and after the COVID-19 pandemic.
In the case of Enterococcus faecium, the resistance rates against penicillin-beta lactamase inhibitor, aminoglycoside, quinolone, and trimethoprim sulfamethoxazole were high (50.0% - 100.0%). On the other hand, the rate of vancomycin resistant Enterococcus faecium in this study was 11.1%, lower than studies by Jahansepas et al. [10] and Azimi et al. [9] (17.0% - 22.0%). One important note was the low rate of E. faecium in this study (3.0%).
This study found in the group of Staphylococcus aureus, the resistance rates against penicillin-beta lactamase inhibitor, 3rd generation cephalosporin, quinolone, aminoglycoside, trimethoprim sulfamethoxazole, fosfomycin decreased from 2019 (12.8% - 23.4%) until 2021 (0.0%) and then increased again in 2022 although lower than 2019 (9.5% - 14.3%). These figures were lower than the resistance rates found in a study by Bitew et al. that were ranging from 20.0% - 66.7% [11] . Resistance rates of MRSA in a study by Scaglione ranged from 23.2% in 2015 to 19.7% in 2019 [7] . This resistance rates were similar with this study (0.0% - 23.4%) and they were decreasing during the four-year study. Bitew et al. also stated that the MDR prevalence rate of S. aureus was 66.7%, which is higher than the rate of MDR in this study (13.4%).
In this study, the resistance rates for K. pneumoniae against penicillin-beta lactamase inhibitor, 3rd generation cephalosporin, quinolone, aminoglycoside, trimethoprim sulfamethoxazole, meropenem and ertapenem peaked from 2019 to 2020 reaching above 50.0%, then decreased in 2021. The resistance rate was the lowest in 2022, ranging 5% - 20%. The resistance rates for 3rd generation cephalosporin, quinolone, aminoglycoside in this study were lower compared to a study by Scaglione et al. (74.9% - 91.4%) [7] , but higher than the study by El-Kady et al. in 2019-2021 (21.6% - 42.3%) [8] , but in 2022 the rates were comparable. El-Kady also found that the MDR rate of K. pneumoniae of 21.4%, which is comparable to this study (24.7%)
Musyoki et al. showed the rate of MDR A. baumannii was 85%, and amikacin were the most effective antibiotics [12] . A study in Morocco in 2019 found that co-trimoxazole was the most effective antibiotics against A. baumannii [13] . Scaglione et al. showed that the resistance rate to carbapenems was in the 2015-2019 was 74.4% [7] . In this study, resistance pattern of A. baumanii was not favorable for most antimicrobials during the first three years of the study, as the rates were above 50.0%, with the exception of tigecycline. The resistance rates peaked from 2019 to 2020, then decreased in 2021, and reached 0.0% in 2022 in most antimicrobials. A. baumanii also showed substantial decrease in rate of MDR from 2019 until 2022 (76.9%, 50.0%, 27.8%, 0.0% respectively). In 2022 there were only two samples of A. baumanii, which decreased from previous years (13 samples, 8 samples, and 18 samples in 2019, 2020, 2021). It is surprising that the samples of A. baumanii decreased drastically in 2022. One study expresses the concern on the challenging clinical problem of A. baumanii as the number of active antibiotics was limited, such as carbapenems and tigecycline [7] . In this study, only tigecycline were highly active against A. baumanii and thus could be used in managing infection.
Azimi et al. [9] reported that 20% of P. aeruginosa was MDR, and Cabral et al. reported MDR rate of P. aeruginosa was 10.7% [14] . In this study, the rates of MDR P. aeruginosa were lower, ranging from 0.0% - 11.1% during 2019-2022. Lari et al. reported high rate of resistance to all antibiotics except colistin [15] . Farhan et al. found that imipenem was the most effective antibiotic [16] . In this study, the resistance rates against ceftriaxone, ertapenem, and tigecycline were very high (88.9% - 100.0%). The resistance rates against aminoglycoside, quinolone, imipenem and meropenem decreased from 2019 until 2021 was in accordance to the result of Farhan et al. (36.3% - 36.4%), and even reached to 0.0% in 2022.
Resistance pattern of Enterobacter spp. against amoxicillin clavulanic reached 100.0% in 2020-2022. Against ceftazidime, ceftriaxone, ciprofloxacinand trimethoprim sulfamethoxazole the rates increased dramatically from 2019 to 2020 then decreased in 2021 and 2022. The resistance against levofloxacin, amikacin, meropenem, and fosfomycin were 0.0% in the four-year study. El-Kadystated that in the past decade, there was an emergence of carbapenem-resistant Enterobacteriaceae [8] , but in the present study this phenomenon did not occur. In the study above, the rate of MDR in Enterobacter spp. was 17.4%, with 0.0% resistance to amikacin. The result of the present study, the rate of MDR were 26.7% during the four-year study, which was higher than the study by El-Kady. One study stated that the MDR rate of Enterobacter spp. would not be considered an important problem as the Enterobacter spp. only account for low number of isolates, which is 5.1% in this study [7] .
It is quite interesting to observe the extreme spectrums of antimicrobial resistance in the era of COVID-19 pandemic. On one end was the drastic increase of resistance to one antibiotic, while on the other end was the absence of resistance to others. There are many factors related to the increase and decrease of antimicrobial resistance in the era of COVID-19 pandemic. Factors related to the increase of antimicrobial resistance are mainly the antibiotic prophylaxis to prevent bacterial co-infections in hospitalized COVID-19 patients, the lack of attention to surveillance of antimicrobial resistance, healthcare facilities overcrowded with patients with COVID-19 patients. The increased number of nosocomial pathogens was also influenced by the increased number of intensive care patients and the use of mechanical ventilation [17] . Other factor that could play a role in the increase of antimicrobial resistance is the infection control measures such as hand and environment hygiene using soap and water, alcohol-based hand sanitizer, or other disinfectants. Before COVID-19 pandemic, this hygiene practice is one of the ways to decrease the development of antimicrobial resistance, but there is also some possibility that it also contributes to emergence of drug resistance [1] .
Scaglione et al. stated that the reasons for dramatic increase of susceptible P. aeruginosa compared to other microorganisms in their study were difficult to explain, as it might be result of antimicrobial stewardship and infection control or this result occurred by chance due to the low number of samples analyzed [1] . This phenomenon also occurred in the case of a few samples of Enterobacter spp. in this study which resistance rates were low or even 0.0% for most antibiotics. In the case of other bacteria where there many samples, similar tendency also occurred. In the case A. baumanii and P. aeruginosa, the decrease of resistance rates to most antibiotics in 2022. The resistance pattern of S. aureus and K. pneumoniae were also lower in 2022 compared to before COVID-19 pandemic. The decrease of resistance rates could be explained by the development of COVID-19 pandemic. As the pandemic commenced in 2020, antibiotic prophylaxis was used in hospitalized COVID-19 patients to prevent bacterial co-infections. The pandemic reached its peak as delta variant dominated in 2021, and antibiotics were still used to treat COVID-19 patients. As the pandemic receded in 2022 when the severity and mortality to COVID-19 decreased, antibiotics use also declined. This decline of antibiotics use could influence the resistance rate of many pathogens including A. baumanii, P. aeruginosa, S. aureus, and K. pneumoniae. As for E. faecium the resistance pattern increased from 2019 to 2021, except for the 2022 as no samples were found.
There are several limitations in this study. First, there was no determination of drug resistance genes of ESKAPE pathogens using molecular methods in this study due to technical limitation in the hospital laboratory. Second, antibiotic resistance index could not be determined because clinical data was not available. Third, there were missing hospital laboratory database on the ESBL-producing organisms. Fourth, the limited number of sample size as this study only accounted for data of single hospital.
5. Conclusion
From this study, it is concluded that the COVID-19 pandemic has affected the antimicrobial resistance pattern of ESKAPE pathogens as one of the etiologies of healthcare-associated infections in Banten province, Indonesia. The resistance rates increased as antibiotic prophylaxis were used in hospitalized COVID-19 patients at the start of the pandemic in 2020 and 2021, along with the lack of attention to surveillance of antimicrobial resistance in the chaotic health situation. As the situation began to resolve in 2022, the resistance rates also decreased, with the exception of a few resistance rates against specific microorganisms.