Study of Antibiograms in Intensive Care Units Patients at a Tertiary Care Hospital

Background and aim: Antibiograms are reports summarizing the rates of bacterial antibiotic susceptibility inside a specific institution over the course of a calendar year. The aim of this study is to ascertain the prevalence and types of pathogens as well as their antibiotic susceptibility and resistance at surgical and emergency Intensive care units (ICUs) at Zagazig University Hospitals. Methods


INTRODUCTION
Infections are an important public health concern, causing significant mortality and morbidity in patients who are hospitalized.They affect 7 The most prevalent infections in intensive care units (ICUs) are the hospital acquired and they have a major negative impact on the outcomes of patients as well as the treatment cost.As a result, timely administration of proper antibiotics is a vital component of these patients' treatment and can save their lives.On the other hand, antibiotic resistance is spreading at frightening rates globally [3].
Antimicrobial resistance (AMR) is a larger problem that involves resistance to medications used for treating various forms of infections, including those caused by bacteria, fungi, and parasites [4].Because of the seriousness of critical diseases, ICUs are regarded as the hub of AMR emergence; patients are at a greater risk of getting infected due to the usage of invasive medical devices (e.g., endotracheal tubes, vascular and urine catheters) as well as excessive antibiotic use along with a variety of infection control procedures.As a result, infection treatment in the ICU has become more challenging, and ICU clinicians need to have routinely updated antibiograms to make prudent decisions concerning the use of empirical medicines while awaiting culture findings [5].
Antibiograms are defined as reports that brief the rates of the antibiotic susceptibility inside a specific institution during a period of one year.Antibiograms are utilized to monitor bacterial resistance and adjust empirical prescriptions for antibiotics [6].Because of the high frequency of AMR and the wide difference in the microorganisms` prevalence and antibiotic susceptibility between ICUs; an ICU-specific antibiogram must guide empirical use of antibiotics.Moreover, new local patterns in bacterial resistance should be examined on a regular basis [7].The aim of the current study is to determine different pathogens as well as their antibiotic susceptibility and resistance at surgical and emergency ICUs at Zagazig University Hospitals.

Study design and ethical consideration:
This cross-sectional retrospective study was conducted in the surgical and emergency intensive care units of Zagazig University Hospitals between January and December 2022.The files of 16,914 clinical isolates acquired from different clinical specimens were analysed.The surgical ICU has 32 beds, and the emergency ICU has 20 beds.During the study period, all the patients admitted in these ICUs exhibited infection-related manifestations.

Inclusion and exclusion criteria
Inclusion criteria included the first isolate culture of a specific species, patient or analysis period, diagnostic isolates, verified final results and antimicrobial drugs that were routinely examined, while surveillance cultures, screening isolates, duplicated bacterial isolates and the isolates with intermediate sensitivity were excluded.Antibiotic susceptibility testing: it was performed with the help of the VITEK® 2 compact system (Biomerieux, Marcy l'etoile, France) using Vitek 2 susceptibility cards (GN 71, GN 204) for the gram-negative bacteria, (GN 222) for the resistant gram-negative bacteria, (GP 67) for the gram-positive bacteria and (AST/Y S07) for the yeast.The results were classified as sensitive (S), intermediate (I), or resistant (R) using the Clinical and Laboratory Standards Institute (CLSI) 2022 criteria.The antibiogram was created in compliance with the Clinical and Laboratory Standards Institute's (CLSI) guidelines [8].

Statistical analysis
Excel 2010 (Microsoft Corporation, USA) was used for statistical analysis.The absolute frequencies and percentages of annual bacterial frequencies and antibiotic sensitivity rates were calculated.

RESULTS
During the study period, 16914 isolates were acquired from different clinical specimens from various ICUs.Positive sputum isolates were the commonest infection site in our ICUs (31.7%) then blood cultures and pus isolates at 23.4% and 22.2% respectively (Table 1).
Gram-negative bacteria were the most commonly identified pathogens (84.27%), with Klebsiella pneumoniae being the most often detected Gramnegative bacteria with a 39.01%incidence, followed by Escherichia coli with a 14.56% incidence (Table 2).2).

Gram-positive
Gram-positive bacteria were the most commonly isolated organisms in blood cultures, while K. pneumoniae was the most commonly isolated pathogen in sputum, urine, and wound cultures (Table 3a, 3b).

Antimicrobial susceptibility testing results
In our investigation, the antibiotic sensitivity of the most often isolated gram-negative infections was extremely variable, revealing that colistin is the most effectively used antibiotic, with sensitivity for K. pneumoniae, E. coli, P. aeruginosa, and Acinetobacter of 95, 89, 92, and 85% respectively.As regards the sensitivity to tigecycline, it was 87% for E. coli, 76% for Acinetobacter, and 75% for K. pneumonia.However, the sensitivity of carbepenem for these organisms was remarkably low.The sensitivity of K. pneumoniae was 14% for imipenem and 13% for meropenem , that of E. coli was 48% for imipenem and 42% for meropenem and that of P. aeruginosa was13% for imipenem and 16% for meropenem while the sensitivity of Acinetobacter was 10% for imipenem and 9% for meropenem) (Figure 3).
Vancomycin sensitivity was 95% for grampositive S. hominis and 87% for MRSA (Fig. 3), while linezolid sensitivity was 100% for MRSA and 98% for S. hominis and Tigecycline sensitivity was 100% for both.Fungal infection in our data was less than 1%, predominantly C. albicans (0.05% vs. 0.01% C. tropicalis), with antifungal sensitivity of about 100% for micafungin, caspofungin, and amphotericin B, while other antifungals' sensitivity was lower as shown in (Figure 4).Table (         Infections caused by gram-negative microorganisms have recently been found to be on the rise around the world.Our findings revealed that the most prevalent pathogens recovered were Gram-negative pathogens (84.27%), this could be attributed to their widespread presence in the hospital environment.Furthermore, their antibiotic resistance may contribute to their survival and spread.K. pneumoniae, gramnegative bacteria, was the most often identified (39.01%).
This Acinetobacter was resistant to cephalosporins with 95% for ceftriaxone (third-generation) and 6 % for cefepime (fourth-generation), aminoglycosides with gentamycim and amikan resistance of 84%, 78% respectively and quinolones resistance of 91% for ciprofloxacin and 95% for levofloxacin in our investigation.In accordance with our results, Acinetobacter was found to be extremely resistant to 3rd-generation cephalosporins (100% for ceftazidime), aminoglycosides with 97% for gentamicin and 95% for amikacin, and fluoroquinolones (100% for ciprofloxacin) in Qadeer et al.'s study [23].
In this study, Colistin was the most effective medication, with 15% resistance, followed by tigecycline (24% .This disparity may be attributable to false-negative reports in our institution, which may be connected to a lack of information regarding the importance of fungal investigations in surgical and emergency ICUs.
Because our hospital is a referral tertiary care facility, the high frequency of resistance found in our investigation could be attributed to prior antibiotic use, prior gram-negative bacterial infections, an unsuitable antibiotic treatment, and patients arriving with severe sepsis and this enhances the chance of the development of multidrug-resistant organisms.This high frequency of resistance is concerning since it necessitates constant surveillance to analyze the sensitivity and resistance pattern at certain levels, which could aid in the selection of the optimal antimicrobial treatment.
Given the large, dangerous, and alarming occurrence of antimicrobial resistance as well as the limited options for empirical antibiotics, a comprehensive antimicrobial resistance campaign should be made a national priority.This programme includes carrying out infectioncontrol policies, the antimicrobial stewardship programme, quality, and education.Using existing antibiogram data, antibiotics will be the only solution for our intensive care units.Combinations and the provision of newly accessible antibiotic generations in our facility until the antimicrobial stewardship programme is fully implemented, not only within our hospital ICUs but in all Egyptian healthcare institutions.
Our research was hampered by a lack of clinical information to discriminate between infections acquired in hospitals and in the community, as well as the data needed to distinguish between actual infection and colonisation.

CONCLUSION
In conclusion, the current study provided local baseline epidemiological data that reveals the scope of our tertiary care hospital's ICU infection problem and can be used to track trends via the construction of cumulative antibiograms and evaluate the effectiveness of preventive measures in the near future.It also showed the problem of high ICU infection rates in Zagazig University Hospitals.To protect the potential of the existing antimicrobial drugs, this local prevalence analysis will help build efficient antimicrobial stewardship.For instance, the use of carbapenem sparing strategies is highlighted by the high resistance of gram-negative bacteria to the drug.Additional prospective multicenter epidemiological studies in multidisciplinary ICUs are needed to appropriately employ antimicrobial stewardship as a strategy for reducing antibiotic resistance in intensive care units across the nation.that reveals the scope of our tertiary care hospital's ICU infection problem and can be used to track trends via the construction of cumulative antibiograms and evaluate the effectiveness of preventive measures in the near future.
 Help building efficient antimicrobial stewardship.For instance, the use of carbapenem sparing strategies is highlighted by the high resistance of gram-negative bacteria to the drug.

 Additional
prospective multicenter epidemiological studies in multidisciplinary ICUs are needed to appropriately employ antimicrobial stewardship as a strategy for reducing antibiotic resistance in intensive care units across the nation.

Figure 1 :Figure 2 :
Figure 1: Incidence of different pathogens isolated from emergency and surgical ICUs.

Figure 5 :
Figure 5: Bar chart showing Antifungal susceptibility of Candida species

Funding:
None.Conflict of interest: None.Ethical approval : The Medical Research Ethics Committee at Zagazig University approved the study (No.ZU-IRB # 10367-24-1-2023) HIGHLIGHTS  Provide local baseline epidemiological data

1): Positive samples prevalence in emergency and surgical ICUs. Items EICU (n=9914) SICU (n=7000) Total (n= 16914)
Emergency intensive care unit, SICU: surgical intensive care unit, BAL: bronchoalveolar lavage, CSF: cerebrospinal fluid.The data were presented in the form of a number and a percentage.
a Positive sputum isolates was the most prevalent infection.

Table ( 2): The incidence of pathogens isolated from emergency and surgical ICUs
The data were presented in the form of a number and a percentage.The most commonly encountered Gramnegative bacteria was the Klebsiella pneumoniae

Table 3 (continue): The incidence of different pathogens in various clinical samples
This difference can be due to the small number of patients in Rajan et al. study which included 501 from medical ICUs and 195patients from surgical ICUs.
). Colistin was the most successful medicine in Qadeer et al.'s research, in agreement with our research results, with only 3% resistance [23].Similarly, Rajan et al. [25] found colistin to be efficient against Acinetobacter, whereas the antibiotic tigecycline was discovered to be most efficient against Acinetobacter by Hasan et al. [28].