Antibiotic Susceptibility Pattern in Clinical Isolates of Pseudomonas aeruginosa

Master of Biomedical Science, Graduate School Hasanuddin University, Makassar, South Sulawesi, Indonesia Department of Microbiology, Faculty of Medicine, Khairun University, Ternate, North Mollucas, Indonesia Department of Microbiology, Faculty of Medicine, Hasanuddin University, Makassar, South Sulawesi, Indonesia Laboratorium of Microbiology, Hasanuddin University Hospital, Makassar, South Sulawesi, Indonesia


INTRODUCTION
Pseudomonas aeruginosa is an obligate aerobic bacterium and can survive well in the environment, such as soil, water, plants, animals, moist surfaces, including in hospitals and medical equipment because of its ability to survive with minimal nutritional requirements and can tolerate a variety of physical conditions. i P. aeruginosa is also known as an opportunistic pathogen in animals and humans. Several reports indicate that these bacteria also cause infection in healthy hosts. ii P. aeruginosa is a bacterium that can inhabit patients with various diagnoses, especially in immunocompromised patients. It causes infections such as pneumonia, gastrointestinal diseases, urinary tract infections, sepsis, peritonitis, skin infections, and burns. iii Antibiotic resistance is the ability of microorganisms to withstand the effects of antibiotics. Pathogenic infections that are resistant to antibiotics require a longer, more complex, and expensive treatment. Currently, antibiotic resistance is a global health problem, both in developed and developing countries. iv Due to high antibiotic resistance and the ability to develop new resistance during antibiotic treatment, P. aeruginosa infections are challenging to eradicate. They can become persistent or even chronic, as physical therapy becomes difficult and ineffective. v Several mechanisms that affect resistance that influence β-lactam resistance in P. aeruginosa is the destruction of the β-lactamase enzyme in antibiotics, changes in the target of antibiotics, decreased intracellular uptake of antibiotics. vi Assessment of the antibiotic susceptibility of nosocomial infectious agents, especially P. Aeruginosa, can lead to selecting appropriate treatment and prevention and control of the emergence of antibiotic resistance in the hospital environment. This study aims to describe the antibiotic sensitivity pattern in clinical isolates of Pseudomonas aeruginosa.

METHODS
The research data were from the antibiotic sensitivity tests conducted at two hospitals, the Microbiology Laboratory of Hasanuddin University Hospital and the Clinical Pathology Laboratory of Dr. Wahidin Sudirohusodo Hospital. The samples were all culture data and antibiotic sensitivity tests from various clinical specimens of patients identified as P. aeruginosa at Hasanuddin University Hospital and Dr. Wahidin Sudirohusodo Hospital, from 1 to September 30, 2019. The inclusion criteria are the sample with the results of the identification test using VITEK 2-Compact was Pseudomonas aeruginosa and the exclusion criteria for the study were incomplete data from both the antibiotic sensitivity test and the patient's diagnosis. There are 13 clinical isolates from the Hasanuddin University Hospital 71 clinical isolates of P. aeruginosa from Dr. Wahidin Sudirohusodo Hospital.
Samples of clinical isolates of P. aeruginosa bacteria are from several specimens, such as sputum, urine, pus, blood, body fluid, ear secretions, and tissues which were detected using the VITEK 2-Compact. Antibiotic sensitivity tests were also carried out with the VITEK 2-Compact. The antibiotics used were ceftazidime (CAZ), meropenem (MEM), amikacin (AK), gentamicin (GN), and piperacillin/tazobactam (TZP).
Data on culture examination and antibiotic sensitivity tests were obtained from patient medical records at Hasanuddin University Hospital and Dr. Wahidin Sudirohusodo Hospital. The data recorded included name, date of birth, medical record number, gender, antibiotic therapy for patient diagnosis, the antibiotic sensitivity pattern, and type of specimen. Then re-examination of the completeness of the data in the laboratory of each hospital.

RESULTS
In this study, there were 13 clinical isolates of P. aeruginosa from Hasanuddin University Hospital, which were isolated from pus (23.1%), sputum (53.8%), ear secretions (15.4%), and tissue (7.7%). In Dr. Wahidin Sudirohusodo Hospital, there were 71 clinical isolates isolated from several specimens, including pus (40.8%), sputum (33.8%), tissue (7.1%), blood (7.1%), ear secretions (4.2 %), urine (2.8%), and body fluids (4.2%). From a total sample of two hospitals, each 7 (53.8%) isolates and 45 (63.4%) isolates were taken from male patients, 6 isolates (46.2%) and 26 (36.6%) isolates were taken from female patients. The most age group was between 46-65 years as many as 6 (46.2%) isolates from Hasanuddin University Hospital and 26 (36.6%) isolates from Dr. Wahidin Sudirohusodo Hospital. The distribution of P. aeruginosa samples based on the type of specimen, sex, and age group shows in table 1. The distribution of P.aeruginosa samples was also grouped based on the category of patient diagnosis. For Hasanuddin University Hospital, the diagnosis of most patients was respiratory disease as many as 6 (46.2%) isolates followed by ear nose and throat disease is 2 (15.4%) isolates. Most diagnoses from Dr. Wahidin Sudirohusodo Hospital, with 13 (18.3%) isolates of nervous disease followed by 12 (17%) isolates of respiratory illness. The distribution of P. aeruginosa samples based on the type of patient's diagnosis shows in table 2. The antibiotic sensitivity pattern of P. aeruginosa shows in Figure 1. Of the five types of antibiotics, the sensitivity of P. aeruginosa is best with the aminoglycoside antibiotics, including gentamicin (100%) at Hasanuddin University Hospital and amikacin (95.8%) at Dr. Wahidin Sudirohusodo Hospital. At Hasanuddin University Hospital followed by antibiotics amikacin (92.3%) and meropenem (84.6%). The sensitivity of P. aeruginosa was lowest to piperacillin/tazobactam antibiotics, but the figure was 69.2%. At Dr. Wahidin Sudirohusodo Hospital, P. aeruginosa also showed good sensitivity to gentamicin (91.5%) and meropenem (77.5%), while the lowest sensitivity shows in piperacillin/tazobactam (60.5%).
Pseudomonas aeruginosa which was resistant to several antibiotics also linked based on the type of specimen. Dr. Wahidin Sudirohusodo Hospital obtained samples with the most resistance from pus specimens that were resistant to ceftazidime (34.5%), meropenem (27.6%), and tazobactam/piperacillin (24.1%), followed by samples from sputum specimens which resistant to ceftazidime (20.8%). At Hasanuddin University Hospital, the sample with the most resistance was sputum specimens with the highest resistance to tazobactam/piperacillin (14,3%). The distribution of resistance samples of Pseudomonas aeruginosa based on the type of specimen is shown in table 3.

DISCUSSIONS
Pseudomonas aeruginosa is a nosocomial and opportunistic pathogen that is often isolated because it causes several infections, including respiratory tract infections, burns, otitis media, and other diseases with high mortality prevalence, especially in immunocompromised patients who are hospitalized. vii P. aeruginosa has intrinsic resistance to various antibiotics and can acquire resistance to other antibiotics during therapy. viii The ability of P. aeruginosa resistance is known to increase and become a global public health problem worldwide. ix This study showed that P. aeruginosa was more isolated from male patients where from a total sample of two hospitals, 7 (53.8%) isolates and 45 (63.4%) isolates were taken from male patients, respectively. The highest age group was between 46-65 years in both hospitals, which is in line with research conducted by Omar B. Ahmed in 2017 in Saudi Arabia, which showed that out of 28 isolates, there were 18 (64.3%) isolates from male patients. However, it is contrary to the age group wherein the dominant age group is above 60 years. 5 For the origin of the specimens in this study, most samples came from pus and sputum at both hospitals. National Antimicrobial Resistance Surveillance, Thailand (NARST) also reported that P. aeruginosa was most commonly found in pus, urine, and sputum specimens. x In this study, the isolated P. aeruginosa isolates had different levels of sensitivity to several antibiotics. The highest level of sensitivity was to the antibiotic gentamicin (100%) for the Hasanuddin University Hospital and amikacin (95.8%) at Dr. Wahidin Sudirohusodo Hospital. These results are in line with the research conducted by Dewi et al in Pekanbaru, which showed the level of sensitivity to amikacin (76.9%) from a total of 121 isolates of Pseudomonas aeruginosa; 93 isolates were sensitive to amikacin. xi Nahid Bavasheh et al. in Iran also showed a good level of sensitivity to amikacin (19.4%) that from 72 isolates, 58 isolates were sensitive to amikacin. 4 The resistance of several antibiotics in this study is most likely due to the prolonged hospitalization time in infectious patients, the use of broad-spectrum drugs at the start of hospitalization, the lack of routine screening for ESBL-producing P. aeruginosa strains, and colonization of multidrug-drug strains resistant. Possible mechanisms of resistance to antibiotics in this study including overproduction of AmpC, a cephalosporinase expressed by the P. aeruginosa chromosomal gene, which causes the most common resistance mechanisms to b-lactams including ESBLs (eg, ceftazidime) and penicillins. Several studies have reported the increasig resistance of P. aeruginosa isolates to cephalosporins. xii,xiii,xiv Carbapenem antibiotics are currently considered the drug of choice to treat the infections caused by ESBL-producing organisms, including Pseudomonas aeruginosa. In this study, 11 (84.6%) isolates at Hasanuddin University Hospital and 55 (77.5%) isolates at Dr. Wahidin Sudirohusodo Hospital are sensitive to meropenem. The result is in line with research conducted by Martina C. Agbo et al. in May until August 2018 at a Hospital in Nigeria, which stated that of 34 clinical isolates of P. aeruginosa there were 29 isolates (85.3%) sensitive to the antibiotic meropenem. xv Another study that is in line with the results of this study is the study of Mohammad Yousef Alikhani in Iran where from 106 isolates, sensitivity to the antibiotic meropenem was shown by 87 isolates (82.1%). xvi This proves that the introduction of carbapenems as a therapy for infection is a significant advance. Carbapenems have become the drug of choice in infections caused by bacteria resistant to penicillin or cephalosporins, especially ESBL-producing strains. xvii

CONCLUSION
This study shows that the level of effectiveness of meropenem, amikacin, and gentamicin are great. It can use as a treatment option in P. aeruginosa infection. This study can help as a reference to prevent mortality and morbidity associated with P. aeruginosa infection.