✅ Due to the variable nature of antibiotic susceptibility patterns and pathogens causing burn wound infection, continuous evaluation, detection of dominant bacterial infections and sensitivity patterns to locally available antibiotics in burn wound patients in order to modify the drug regimen for proper antibiotic treatment is important and seems reasonable.
With the advancement of perinatal and neonatal medicine, as well as the development and equipping of neonatal intensive care units (NICUs), the survival of critically ill infants has increased today. One of the problems that infants have with birth is hearing disorder. In this regard, 80% of hearing reduction occurs in congenital infants, and this disorder does not occur until they reach the age of speech and language. Also, two-thirds of infants have hearing parents, which causes parental attention to hearing problems in infants.
On the other hand, the prevalence of congenital hearing loss is 1 to 2 cases per 1000 live births, which is more common than disorders such as Congenital Hypothyroidism and Phenylketonuria (1-4). This disorder in infants with risk factors (birth weight less than 1250 g, Apgar score less than 3 and 6 at 1, and 5-min seizures, ventilator therapy, meningitis, jaundice) associated with Asphyxia, and Aminoglycoside; So, Furosemide treatment are more common (3–8). Hearing problems and brainstem dysfunction are also more common in neonates treated in ICUs (9,10). Early detection of hearing disorders is a measure, which is suitable for speech and behavioral development (11,12).
The importance of early auditory screening has long been recognized, with two main goals. The short-term goal is to diagnose hearing loss early. Its long-term goal is to perform timely interventions in the field of hearing rehabilitation, improving the prognosis of speech and cognitive development (2,3,6,12). Organizations around the world have adopted nationwide hearing screening. Prior to 1990, hearing screening was performed on infants at risk. In 2000, the American Infant Surveillance Committee recommended a hearing examination of all infants before release from the hospital. In 2014, 97% of American infants were given a hearing test at birth. More than half of the infants with hearing loss were diagnosed. These issues indicated the need for a hearing test at birth (13(.
Otoacoustic emission (OAE) testing has long been a standard practice for the neonatal hearing screening. On the other hand, the auditory brainstem response (ABR) test is a gold standard for assessing the auditory level (the function of the eighth nerve and the auditory pathways of the brainstem )14,15(. In this regard, studies have stated their goals in the diagnosis of infants with hearing loss before three months of age and the initiation of treatment and rehabilitation before six months of age (12). Moreover, hearing is a key solution for communication and the basis of learning. Therefore, this study was designed and implemented to evaluate hearing (ABR and OAE) of the neonates hospitalized and treated in NICU of Besat Hospital in Hamadan, Iran.
Sample Collection
The current study was conducted over a 12-month period (March 2017 to April 2018) at Imam Musa Kazem burn hospital in Isfahan, Iran. About 1500 burn wound samples were collected from the hospitalized patients (784 men and 716 women) in different wards of the hospital.
Sampling of the burn wound was performed after removing the dressings and removing local antibacterial agents and wound cleaning by washing with sterile saline solution (0.9% NaCl).
In order to get enough cellular material for culture, the end of two sterile swabs were transmitted by at least one centimeter of the open wound. Adequate pressure should be applied to the tip of the swabs to bleed a little into the underlying tissue (24).
Sample Processing
The first swab was used for direct smear and gram staining to examine bacteria and diagnose PMNL, which is an important feature in the case of bacterial infection, which must be distinguished from bacterial cloning )23(.
Culture
The swabs were cultured as streak on blood and MacConkey agar plates and incubated for 24 h of aerobic incubation at 37°C. Conventional bacteriological methods (Gram-stain, catalase test, oxidase test, indole test, Methyl red (MR) and Voges–Proskauer (VP) test, Citrate test, urease test, coagulase test, Novobiocin resistance, Hemolysis type, Susceptibility to Bacitracin, Optochin, Hydrolysis of cAMP, Hydrolysis by Bile esculin, Growth in 6.5% NaCl, oxidative-fermentative (OF) test, triple sugar iron agar (TSIA)) were done for the isolation and identification of the bacteria (25).
Antibiotic Susceptibility Tests
Antimicrobial resistance tests were done according to clinical laboratory standards institute guidelines via Kirby-Bauer disk diffusion method. Their interpretation was based on the CLSI-2018 tables (26). Antibiotics included Ciprofloxacin (5 μg), Amikacin (30μg), Ceftazidime (30μg), Nalidixic acid (30μg), Piperacillin (100μg), Imipenem (10μg), Meropenem (10μg), and Vancomycin (30μg), Ceftriaxone (30μg), Penicillin (10 units), Piperacillin – Tazobactam (100/10μg), Tobramycin (10μg) (American Bidi). The test was performed on Mueller-Hinton agar (Merck, Germany). E. coli ATCC 25922 strain was used as a control (27).
Approval to conduct the study was obtained from the Research Ethics Committee of Isfahan University of Medical Sciences (ID- number: IR.MUI.RESEA RCH.REC.1397.114).
Data Analysis
Data were analyzed via SPSS 24. (SPSS Inc., IL., USA). P-value≤0.05 was considered statistically significant
Of the 1500 cultured samples, 957 (63.8%) included bacterial isolates and 543 wound swabs were (36.2%) sterile.
Bacterial Colonization Pattern of Burn Wounds Infections
Different types of bacterial isolates were isolated from burn wound infection and biopsy of burn wound infection, of which 146 were Gram positive and 815 were Gram negative.
The results clearly showed that A. baumannii with 34.7% frequency and P. aeruginosa with 29.6% frequency were the most common Gram-negative bacterial isolates and S. aureus with 10.2% frequency was the most common Gram-positive bacterial isolate (Table 1).
The prevalence of bacterial isolates among different wards of the hospital showed that burn wound infection was the most frequent in ICU patients (50.2%) and the least in restoration patients (6.6%) (Table 2).
According to the results, 50.7% of isolates showed MDR resistance. The results of antibiotic susceptibility tests showed that the most resistant isolates to 14 antibiotics examined were A. baumannii and P. aeruginosa isolates (Table 3).
Antibiotic Resistances of A. baumannii
Among the A. baumannii isolates, the highest resistance to Ciprofloxacin (91.9%) and then to Meropenem (81.75%) were observed. The highest sensitivity to Tobramycin (56.9%) was reported (Figure 1).
Antibiotic Resistance of P. aeruginosa
Among P. aeruginosa isolates, the highest resistance to Ceftazidime (95.6%) and then to Ciprofloxacin (92.8%) were seen. The highest sensitivity to Amikacin (57.9%) was found (Figure 1).
Antibiotic Resistance of S. aureu:
Among S. aureus isolates, the highest resistance were seen to Penicillin (63.2%) and then to Ciprofloxacin (52%). The highest sensitivity was found to be to Vancomycin (96%) (Figure 2).
Table 1. Rate of bacterial pathogens isolated in burn patients
Percentage (number) | Types of bacteria |
34.9%(334) | A. baumannii |
29.8%(285) | P. aeruginosa |
10.2%(98) | S. aureus |
8.3%(80) | K. pneumoniae |
5.2%(50) | Other non-fermenting Gram-negative bacilli |
4.8%(46) | Coagulase-negative Staphylococcus sp. |
3.4%(33) | E. cloacae |
1.2%(10) | E. coli |
1.3%(12) | Others Enteribacteriaceae |
0.09(9) | Enterococcus |
100%(957) | Total |
Table 2. Prevalence of bacterial infection among different wards of the hospital
Total | Restoration | Burn | Emergency | ICU | Wards Isolate |
334 | 8 | 43 | 54 | 229 | A. baumannii |
285 | 7 | 50 | 57 | 171 | P. aeruginosa |
98 | 5 | 30 | 44 | 19 | S. aureus |
80 | 25 | 14 | 14 | 27 | K. pneumoniae |
50 | 4 | 16 | 11 | 19 | Other non-fermenting Gram-negative bacilli |
46 | 7 | 17 | 14 | 8 | Coagulase-negative Staphylococcus sp. |
33 | 6 | 10 | 12 | 5 | E. cloacae |
10 | 1 | 1 | 5 | 3 | E. coli |
12 | 0 | 5 | 7 | 0 | Others Enterobacteriaceae |
9 | 1 | 3 | 5 | 0 | Enterococcus |
957 | 64 | 189 | 223 | 481 | Total |
Table 3. Antimicrobial resistance pattern
ANTIBUTICS ISOLATES | A.baumanii | P.aeroginosa | S. aureus | K.pneumoniae | ONGNF | CON | E. cloacae | E. coli | OENT | Enterococcus |
---|---|---|---|---|---|---|---|---|---|---|
CP | 310 (92.8%) |
262 (91.9%) |
51 (52%) |
53 (66.2%) |
37 (74%) |
15 (32.6%) |
16 (48.5%) |
6 (60%) |
5 (41.6%) |
5 (55.5%) |
AN | 207 (61.9%) |
165 (57.9%) |
27 (27.5%) |
18 (20%) |
28 (56%) |
5 (11%) |
5 (15%) |
4 (40%) |
4 (33.3%) |
4 (44.4%) |
CAZ | 314 (95.6%) |
197 (69.1%) |
* | 15 (18.75%) |
27 (54%) |
* | 8 (24.2%) |
4 (40%) |
4 (33.3%) |
* |
NA | * | * | 21 (21.4%) |
* | * | 5 (11%) |
0 | * | * | 4 (44.4%) |
PIP | 215 (64.4%) |
196 (68.7%) |
35 (35.7%) |
14 (17.5%) |
34 (68%) |
10 (22%) |
9 (27.3%) |
3 (30%) |
4(33.3%) | 3(33.3%) |
IMP | 223 (66.7%) |
20 3(71.2%) |
* | 27 (33.7%) |
31 (62%) |
* | 10 (30%) |
4 (40%) |
3 (25%) |
* |
MEN | 220 (65.8%) |
233 (81.75%) |
* | 38 (47.5%) |
27 (54%) |
* | 11 (33.3%) |
4 (40%) |
4 (33.3%) |
* |
V | * | * | 8I | * | * | 0 | * | * | * | 0 |
CC | * | * | 27 (27.5%) |
* | * | 11 (24%) |
* | * | * | 3 (33.3%) |
CRO | 296 (88.6%) |
209 (73.33%) |
* | 41 (51.2%) |
32 (64%) |
* | 15 (45.4%) |
7 (70%) |
7 (58.3%) |
* |
p | * | * | 62 (63.2%) |
* | * | 21 (45.6%) |
* | * | * | 5 (55.5%) |
TZP | 224 (67%) |
188 (65.9%) |
* | 28 (35%) |
26 (52%) |
* | 10 (30%) |
1 (10%) |
1 (8.3%) |
* |
TOB | 190 (56.9%) |
230 (80.7%) |
45 (45.9%) |
13 (16.3%) |
16 (32%) |
5 (11%) |
8 (24.2%) |
2 (20%) |
1 (8.3%) |
4 (44.4%) |
Figure 1. Resistance of A. baumannii and P. aeruginosa to antimicrobial drugs.
Figure 2. Resistance of S. aureus to antimicrobial drug.
Discussion
Wound infection is one of the most common burn problems originating from nosocomial infections. The severity of infections in burn wounds is important because of their effects on the course of the disease and subsequently on patients. Most of the burn patients died of infection during the hospitalization. The prevalence of infections in burn wounds is high in developing countries because it is likely to decline the hygiene in poorer socioeconomic status. Malnutrition also plays an important role in the rapid acquisition of infection (28,29). Families and hospital personals who are in closer contact with the patient may also be the source of the infection. Negligence towards the hygiene laws, lack of sterile bandages, clothing and patient care equipment, Long-term catheterization, and inadequate antibiotic treatment are among the most important causes of nosocomial infections (28). In the present study, the most common infections were A. baumannii (34.9%), P. aeruginosa (29.8%) and S. aureus (10.2%). The results were similar to many studies showing that A. baumannii and P. aeruginosa are the most prevalent bacteria isolated from burn wounds (30); however, these results contradict with some other studies showing that S. aureus is the most common isolate (28,31). A. baumannii is one of the most frequent nosocomial infection bacteria widely isolated from hospital environment and equipment (32). These bacteria have also been widely reported in the ICU ward. In the present study, A. baumannii was the most isolated strain of patients admitted to the ICU ward. For the last two decades, P. aeruginosa has been a very important pathogen and accounting for a large proportion of nosocomial infections. P. aeruginosa infections are particularly prevalent among burn wound patients (33-35). Determining the pattern of antibiotic resistance is very important for epidemio-logical surveillance programs and treatment alternatives in burn patients. Antibiotic resistance is the most serious causes for concern, as common bacterial isolates resistant to antimicrobial agents are the most important cause of death in burn patients. In the current study A. baumannii and P. aeruginosa were found to be the most resistant isolates. The highest resistance was seen to Ciprofloxacin and the lowest resistance of A. baumannii was seen to Tobramycin and the lowest resistance of P. aeruginosa was seen to Piperacillin-Tazobactam. Whereas in Bayram’s study, A. baumannii and P. aeruginosa resistance to Imipenem was high (30).
S. aureus is the third isolate in the list of bacterial isolates. Unlike other studies, the incidence of Penicillin resistance was the highest. Optimal training of burn ward personals, wash and hand hygiene personnel before and after contact with each patient, avoiding crowded appointments, restricting inter-wards hospital exchanges, monitoring the prevention of bacterial infections, attention to antibiotic resistance patterns and effective nosocomial infection control programs all are very important and effective in preventing burn wound infection and its subsequent problems.
Conclusion
Due to the variable nature of pathogens causing burn wound infection, continuous evaluation and detection of dominant bacterial infections and their sensitivity patterns, in order to modify the drug regimen for proper antibiotic treatment is important to prevent antibiotic resistance and it seems reasonable. An effective infection control program is required in all wards of the burn hospital to prevent the spread of nosocomial burn wound infections. Staffs from all wards of the hospital need to work closely with the hospital acquired infection.
Acknowledgements
The authors would like to thank hospital lab personnel of the Musa Kazem burn hospital in Isfahan and the bacteriology group of Isfahan University of Medical Sciences for supporting this study.
Conflicts of Interest
Authors declared no conflict of interests.
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