• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1377-1383
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• 2006

Among 46 Acinetobacter baumannii isolates collected in 2004, two imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Republic of Korea. Two carbapenemase-producing isolates were further investigated to determine the mechanism of resistance. These isolates were analyzed by antibiotic susceptibility testing, microbiological tests of carbapenemase activity, determination of pI, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. Two cases of infection by A. baumannii producing the IMP-1 ${\beta}$-lactamase were detected. The isolates were characterized by a modified cloverleaf synergy test and EDTA-disk synergy test. Isoelectric focusing of crude bacterial extracts revealed nitrocefin-positive bands with a pI value of 9.0. PCR amplification and characterization of the amplicons by direct sequencing indicated that the isolates carried a $bla_{IMP-l}$ determinant. The isolates were characterized by a multidrug resistance phenotype, including penicillins, extended-spectrum cephalosporins, carbapenems, and aminoglycosides. These results indicate that the observed imipenem resistance of two Korean A. baumannii isolates was due to the spread of an IMP-1-producing clone. Our microbiological test of carbapenemase activity is simple to screen class B metallo-${\beta}$-lactamase-producing clinical isolates to determine their clinical impact and to prevent further spread. This study shows that the $bla_{IMP-l}$ resistance determinant, which is emerging in Korea, may become an emerging therapeutic problem, since clinicians are advised not to use extended-spectrum cephalosporins, imipenem, and aminoglycosides. This observation emphasizes the importance of having effective control measures in Asian hospitals, such as early detection of colonized patients, isolation procedures, and a judicious use of antibiotics.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.97-102
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• 2011

The Multidrug-resistant Acinetobactor baumanii (MDRAB) is an opportunistic pathogen. Patients with long periods of hospital stay and/or under intensive care unit (ICU) receiving invasive management are more susceptible to this pathogen. In this report, four children with MDRAB infection are reviewed and described their clinical characteristics. There had been concurrent outbreaks of MDRAB infection in adult patients in the ICU at this period of time. The first child had received a craniotomy and epidural hematoma evacuation. The second child was admitted for status epilepticus with hydrocephalus. The third child had pneumonia with status epilepticus with hydrocephalus. The fourth child had poor activity due to hypoxic ischemic encephalopathy and convulsive disorder. Except the fourth child, all had not been exposed to carbapenem prior to infection of MDRAB. That imply the cause of MDRAB infections may be associated with invasive management and prolonged hospitalization together with the previous exposure to carbapenem in our cases. We would like to emphasize the importance and minimizing the spread of hospital infection in patients under prolonged intensive care management regardless of the use of carbapenem.

• Tuberculosis and Respiratory Diseases
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• v.74 no.2
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• pp.63-69
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• 2013

Background: Aiming to improve outcome of lung transplantation (LTx) patients, we reviewed risk factors and treatment practices for the LTx recipients who experienced respiratory infection in the late post-LTx period (>1 month after LTx). Methods: We analyzed the clinical data of 48 recipients and donors from 61 LTx, who experienced late respiratory infections. Late respiratory infections were classified according to the etiology, time of occurrence, and frequency of donor-to-host transmission or colonization of the recipient prior to transplantation. Results: During the period of observation, 42 episodes of respiratory infections occurred. The organisms most frequently involved were gram (-) bacteria: Acinetobacter baumannii (n=13, 31.0%), Pseudomonas aeruginosa (n=7, 16.7%), and Klebsiella pneumoniae (n=4, 10.0%). Among the 42 episodes recorded, 14 occurred in the late post-LTx period. These were bacterial (n=6, 42.9%), fungal (n=2, 14.3%), viral (n=4, 28.5%), and mycobacterial (n=2, 14.3%) infections. Of 6 bacterial infections, 2 were from multidrug-resistant (MDR) A. baumannii and one from each of MDR P. aeruginosa, extended spectrum ${\beta}$-lactamase (+) K. pneumoniae, methicillin-resistant Staphylococcus aureus and Streptococcus pneumoniae. Infection-related death occurred in 6 of the 14 episodes (43%). Conclusion: Although the frequency of respiratory infection decreased sharply in the late post-LTx period, respiratory infection was still a major cause of mortality. Gram (-) MDR bacteria were the agents most commonly identified in these infections.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.52-61
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• 2022

Purpose: Most cases of oral and maxillofacial infections are usually easily treated by proper diagnosis, elimination of causative factors, and antibiotic therapy. However, the emergence and the increase of multidrug-resistant bacteria make treatment challenging. "ESKAPE" pathogens are the most common opportunistic organisms in nosocomial infections and have resistant to commonly used antibiotics. There are many medical reviews of ESKAPE pathogens, but few in dentistry. This study focuses on oral and maxillofacial infection especially with ESKAPE pathogens. The purpose of this study is to prepare feasible data about tracing and treatment of infection related to pathogens that may be beneficial to clinicians. Methods: A total of 154 patients with oral and maxillofacial infections were reviewed by analyzing retrospectively hospitalized data in the Department of Oral and Maxillofacial surgery, Chosun University Hospital, Korea, past 5 years from January 2014 to December 2018. Based on the medical records and microbiological tests, the results were divided into two groups: infections with ESKAPE pathogens and other bacteria. Results: A total of 22 species were isolated from 154 patients. The proportion of ESKAPE pathogens among all bacterial isolates collected from infected patients was 39.6%. Causative factors, especially in post-operative infection, showed a statistically significant correlation to ESKAPE infections (29 cases). And average of treatment period in ESKAPE group was longer than non-ESKAPE groups. Overall, Klebsiella pneumoniae (60.7%) was the most frequently isolated ESKAPE pathogen. And high antibiotic resistance rates had been detected in the ESKAPE during the five-year period. Conclusions: Infections with ESKAPE pathogens are now a problem that can no longer be overlooked in Dentistry. Based on results of this study, ESKAPE pathogens were highly associated with post-operative or opportunistic infections. Clinicians should be careful about these antibiotic resistant pathogens and use appropriate antibiotics to patients while having dental treatments.

• Journal of Yeungnam Medical Science
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• v.28 no.2
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• pp.133-144
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• 2011

Background: Tigecycline (TIG), a new broad-spectrum glycylcycline with anti-multidrug-resistant-(MDR)-pathogen activity, was launched in March 2009 in South Korea, but there are insufficient clinical studies on its use in the country. As such, this study was performed to analyze cases of severe MDR-pathogen-caused infections treated with TIG. Methods: Patients treated with TIG within the period from May 2009 to June 2010 were enrolled in this study. Their clinical and microbiologic data were reviewed retrospectively. Results: Twenty-one patients were treated with TIG for complicated skin and soft-tissue infections (cSSTIs) (42.9%), complicated intra-abdominal infections (cIAIs) (38.1%), or pneumonia (19.1%) caused by MDR pathogens like carbapenem-resistant $Acinetobacter$ $baumannii$ (76.2%), methicillin-resistant $Staphylococcus$ $aureus$ (61.9%), extended-spectrum beta-lactamase-producing $Escherichia$ $coli$ and $Klebsiella$ $pneumoniae$ (38.1%), and penicillin-resistant $Enterococcus$ species (33.3%). Thirteen patients (61.9%) had successful clinical outcomes while five (23.8%) died within 30 days. The rate of clinical success was highest in cSSTI (77.8%), followed by cIAI (50%) and pneumonia (50%), and the mortality rate was highest in pneumonia (50%), followed by cIAI (25%) and cSSTI (11.1%), Conclusion: Tigecycline therapy can be an option for the treatment of severe MDR-pathogen-caused infections in South Korea, Due to its high risk of failure and mortality, however, prudence is required in its clinical use for the treatment of severe infections like nosocomial pneumonia.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5787-5791
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• 2014

Background: With increasing survival periods and diversification of treatment methods, treatment of critically ill cancer patients has become an important factor influencing patient prognosis. Patients with cancer are at high risk of infections and subsequent complications. This study investigated the incidence and factors contributing to the development of ventilator-associated pneumonia (VAP). Materials and Methods: This retrospective study investigated the incidence of VAP and factors leading to infection in patients admitted to the intensive care unit (ICU) of a cancer center from January 1, 2012 to December 31, 2013. Results: The incidence of VAP was 2.13 cases per 1,000 days of intubation, and 13 of 288 patients (4.5%) developed VAP. Lung cancer was the most common cancer associated with VAP (N=7, 53.9%), and longer hospital stays and intubation were associated with increased VAP incidence. In the group using a "ventilator bundle," the incidence was 1.14 cases per 1,000 days compared to 2.89 cases per 1,000 days without its use; however, this difference was not statistically significant (p=0.158). Age (${\geq}65$, OR=5.56, 95% confidence interval [CI]=1.29-23.95), surgery (OR=3.78, 95%CI=1.05-13.78), and tracheotomy (OR=4.46, 95%CI=1.00-19.85) were significant VAP risk factors. The most common causative organisms were methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (N=4, 30.8% each), followed by Acinetobacter baumannii and Candida albicans (N=2, 15.4% each). Conclusions: The incidence of pneumonia among critically ill cancer patients is highest in those with lung cancer, but lower than among non-cancer patients. The length of hospital stay and time on mechanical ventilation are important risk factors for development of VAP. Although not statistically significant, "ventilator bundle" care is an effective intervention that delays or reduces incidence of VAP. Major risk factors for VAP include age (${\geq}65$ years), surgery, and tracheostomy, while fungi, gram-negative bacteria, and multidrug-resistant organisms were identified as the major causative pathogens of VAP in this study.

• Journal of Oral Medicine and Pain
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• v.46 no.3
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• pp.75-83
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• 2021

Odontogenic infection in the oral and maxillofacial regions caused by bacteria (mostly of oral origin) is one of the most common diseases encountered by dentists. Localized infection can easily be treated with incision and drainage followed by antibiotics. Emergence of multidrug resistant (MDR) bacteria called "Superbacteria" has become one of the serious problems in modern society, due to its small window of opportunity for treatment and high casualty. The acronym "ESKAPE", encompassing the common and serious MDR pathogens stand for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. Literature search was performed in Medline, PubMed and Google Scholar ranging from 2012 to 2020. ESKAPE patient's infection period was longer than that of non-ESKAPE group, and the treatment method due to antibiotic resistance was also complicated. The purpose of this study is to investigate infection caused by ESKAPE pathogens in the oral and maxillofacial regions through literature review and to inform dental surgeons of the danger of ESKAPE pathogens and to suggest viable treatment options. Many studies worldwide reported infections associated with ESKAPE pathogens, but only limited number of studies targeted infection in oral and maxillofacial regions. Further research is required with more data on ESKAPE bacteria and their infection, especially in oral and maxillofacial regions.

• Microbiology and Biotechnology Letters
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• v.50 no.1
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• pp.147-156
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• 2022

Urinary tract infections (UTIs) are one of the most common infections in different age groups, including children. Bacteria are the main etiological agents of UTIs. The aim of the present study was to isolate, identify, and determine the antibiotic susceptibility of bacteria isolated from children with UTIs from Baghdad, Iraq. Three hundred and two urine samples were collected from children aged 6 months to 12 years. The samples were cultured on blood agar and MacConkey agar. The selected colonies were subjected to biochemical tests and antibiotic susceptibility analysis using the Vitek^® 2 Compact automated microbial identification system. In this sample, 299 bacteria were identified, of which, 267 were gram-negative bacteria, and 32 were gram-positive bacteria. Escherichia coli (56%) was the most commonly isolated gram-negative bacteria, followed by Pseudomonas aeruginosa (14%), Enterobacter spp. (10.48%), Klebsiella pneumoniae (9.36%), Proteus spp. (7.8%), Acinetobacter baumannii (1.5%), and Morganella morganii (0.37%). Enterococcus faecalis (62.5%) was the most commonly detected gram-positive bacteria, followed by Staphylococcus aureus (37.5%). E. coli and P. aeruginosa were the most antibiotic-resistant bacteria. Among the tested antibiotics, meropenem showed 100% sensitivity, followed by imipenem (97.4%), amikacin (91.8%), and tobramycin (83.5%). In contrast, the high frequencies of resistance were observed with cefixime (93.2%), cefotaxime (78.7%), and ceftriaxone/cefotaxime (71.2%). In conclusion, carbapenems and aminoglycosides are highly recommended for the empirical treatment of UTIs, while, Quinolones, penicillins, and cephalosporins are not suggested. Frequent antibiotics susceptibility testing are warranted to determine the resistance pattern of UTI bacteria.

• Tuberculosis and Respiratory Diseases
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• v.72 no.1
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• pp.30-36
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• 2012

Background: Patients with ventilator-associated pneumonia (VAP) in intensive care unit (ICU) have a high mortality rate. The routine surveillance cultures obtained previously or an ATS guideline for hospital-acquired pneumonia was used in selecting initial antimicrobials. The object of this study was to compare the respiratory samples before VAP and bronchoalveolar lavage (BAL) culture. Methods: 54 patients underwent fiberoptic bronchoscopy to obtain BAL samples. We reviewed microbiologic specimen results of prior respiratory specimens (pre-VAP) and BAL. Results: Among 51 patients with 54 VAP episodes, 52 microorganisms of pre-VAP and 56 BAL samples were isolated. Pre-VAP included 21.2% of MRSA, and 32.6% of multidrug resistant-Acinetobacter baumannii (MDR-AB). BAL samples comprised 25.0% of MRSA, 26.7% of MDR-AB, 14.3% of Stenotrophomonas maltophilia and 3.6% of Klebsiella pneumonia in order. In pre-VAP samples compared to BAL samples, only 35.2% were identical. In BAL samples compared to pre-VAP samples obtained in 5 days before the onset of VAP, only 43.6% were identical. However, among BAL samples compared to pre-VAP samples obtained after more than 5 days, 13.3% were identical (p=0.037). Conclusion: Based on these data, pre-VAP samples obtained prior to 5 day onset of VAP may help to predict the causative microorganisms and to select appropriate initial antimicrobials.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.135-142
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• 2011

Purpose : Hospital associated infection (HAI) caused by multidrug-resistant (MDR) microorganisms has been recognized as an important issue in the world, especially in critically ill patients such as the patients admitted in the intensive care unit. There are fewer papers about MDR-HAI in pediatric patients compared to adult patients. In this study, we investigated the incidence and associated factors of MDR-HAI in children admitted to the intensive care unit (ICU) of a university hospital. Methods : We retrospectively evaluated 135 children who were admitted in ICU for at least 3 days between January 2009 and December 2010. HAI cases were divided into MDR-HAI group and non-MDR-HAI group. Clinical characteristics and various associated factors were compared between those groups. Results : In 39 patients, 45 cases of ICU-related HAI were developed. ICU-related HAI incidence was 47.7 per 1000 patientdays. Thirty-six cases (80.0%) were MDR-HAI. Acinetobacter baumannii was isolated more commonly in MDR-HAI group. And the followings were found more frequently in MDR-HAI group than non-MDR-HAI group: medical condition as an indication for ICU admission, mechanical ventilation, urinary catheterization and previous use of broad-spectrum antibiotics. Among the risk factors, previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. Conclusion : ICU-related HAI incidence was higher than previously reported. Previous use of broad-spectrum antibiotics was the independent risk factor for MDR-HAI. To investigate the characteristics of MDR-HAI in children admitted in ICU, further studies with a larger sample size over a longer period of time are warranted.