Safety of Temporary Use of Recycled Autoclaved Femoral Components in Infected Total Knee Arthroplasty: Confirming Sterility Using a Sonication Method

BACKGROUND: The purpose of this study was to evaluate the usefulness of sonication technique for microbiological diagnosis and the sterility of the recycled autoclaved femoral components from infected total knee arthroplasty (TKA) using a sonication method. METHODS: Nineteen femoral implants explanted from patients with infected TKA were sterilized with a standard autoclave method. Standard culture of the fluid before and after sonication of the sterilized implants was performed to detect pathogenic microorganisms. Additional experiments were performed to evaluate the sterility of the recycled implant by inducing artificial biofilm formation. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated into 10 implants and sterilization in a standard autoclave was performed, and then the fluid was cultured before and after sonication. RESULTS: Two of the 19 sterilized implants were positive for growth of bacteria after sonication, whereas no growth was detected in the cultured fluid from the sterilized implants before sonication. The bacteria were Staphylococcus species in all two cases. In one of 10 implants inoculated with MRSA, the culture was positive for growth of bacteria both before and after sonication. However, Staphylococcus epidermidis was cultured from both occasions and thus this implant was thought to be contaminated. CONCLUSIONS: We found sonication for identification of pathogens could be helpful, but this finding should be interpreted carefully because of the possibility of contamination. Sterilization of an infected femoral implant with an autoclave method could be a good method for using the temporary articulating antibiotic spacer in two-stage revision arthroplasty.

Antimicrobial Susceptibility and Characterization of Propionibacterium acnes by Multilocus Sequence Typing and Repetitive-Sequence-Based PCR

Propionibacterium acnes, a gram-positive, anaerobic, and aerotolerant bacterium that is found frequently in the skin as part of the human microbiome causes inflammatory acne, shoulder infection, and the contamination of medical devices. The study goals were the antibiotic resistant and molecular epidemiological characterization of the P. acnes isolates in Korea. A total of 22 P. acnes isolates originated from diverse patients were obtained from three National Culture Collections for Pathogens in South Korea. The hemolytic properties and minimum inhibitory concentrations (MIC) of five antibiotics (tetracycline, doxycycline, clindamycin, erythromycin, and minocycline) were determined. Only one isolate showed high MIC values and resistance to all five antibiotics. Genotypic characterization was achieved by multilocus sequence typing (MLST) for eight loci (aroE, guaA, tly, camp2, atpD, gmk, lepA, and sodA) and repetitive-sequence-based PCR (rep-PCR) analysis using the DiversiLab kit. MLST revealed four phylogroups that were type IA₁ (27.3%), type IA₂ (18.2%), type IB (13.6%), and type II (40.9%). Rep-PCR results demonstrated three clusters that were cluster I (39.1%), cluster II (45.5%), and cluster III (13.6%). The isolates of cluster I were part of phylogroup type IA (both IA₁ and IA₂), and the isolates of cluster II belonged to phylogroup type II. All isolates of phylogroup type IB were hemolytic and belonged to cluster III. The results of rep-PCR clustering analysis showed a good correlation with those of MLST phylogroups, suggesting that rep-PCR could be an alternative method to track P. acnes subtype lineages.

Detection of Bacterial Species in Chronic Periodontitis Tissues at Different Stages of Disease Severity

The goal of this research was to determine the relationship between the stage of chronic periodontitis and the presence of six bacterial pathogens (Aggregatibacter actinomycetemcomitans: AA, Fusobacterium nucleatum: FN, Porphyromonas gingivalis: PG, Prevotella intermedia: PI, Enterococcus faecalis: EF, and Parvimonas micra: PM). Forty-six chronic periodontitis patients visiting a dental hospital were included in this investigation. They were classified into four chronic periodontitis stages based on the sulcus bleeding index value and the probing depth. The tissue samples from the periodontal surgery were used for a direct PCR detection assay. A total of 49 samples from 46 patients were collected and classified into four chronic periodontitis groups (N: 6, P1: 13, P2: 18, P3: 12). The PCR assay showed that FN, PI, and PM were involved from the beginning of chronic periodontitis (P1), while AA and PG existed regardless of the disease stages. EF was strongly linked to the P3 stage of the disease. In order to assess the effect of dental treatments on patients with chronic periodontitis, EF should be a critical marker for P3 patients, while FN, PI, and PM would be good indicators for chronic periodontitis.

A Virulent Salmonella enterica Serovar Enteritidis Phage SE2 with a Strong Bacteriolytic Activity of Planktonic and Biofilmed Cells

Salmonella enterica serovar Enteritidis is one of the major food borne pathogens. Utilizing lytic bacteriophages against this pathogen can be a new and effective approach for the prevention of food-contamination and food-borne infection. In this study, we isolated and characterized a Salmonella Enteritidis specific lytic bacteriophage (phage SE2). The bacteriolytic activity of planktonic and biofilmed cells against an antibiotic resistant strain of Salmonella Enteritidis was also evaluated. Phage SE2 revealed an efficient bacteriolytic effect with biofilm dispersing ability and could maintain its virulence even at extreme pH and temperature. It can be a potential biotherapeutic agent against Salmonella Enteritidis.

Salmonella Serovars from Foodborne and Waterborne Diseases in Korea, 1998-2007: Total Isolates Decreasing Versus Rare Serovars Emerging

Salmonella enterica has been one of the most widespread foodborne pathogens in Korea. Between 1998 and 2007, a total of 9,472 Salmonella isolates were identified from foodborne and waterborne illness patients. During that time, Korea was transitioning into a developed country in industry as well as in its hygiene system. Although the isolation number of total Salmonella including serovar Typhi has decreased since 1999, the isolation of rare Salmonella serovars has emerged. Three most prevalent serovars during 1998-2007 were S. enterica Typhi, S. enterica Enteritidis, and S. enterica Typhimurium. There were remarkable outbreaks caused by rare serovars such as S. enterica Othmarschen, S. enterica London and S. enterica Paratyphi A, and overseas traveler-associated infections caused by S. enterica Weltevreden and S. enterica Anatum. Salmonella serovars from overseas travelers made a diverse Salmonella serovar pool in Korea. This study is the first review of the status of the human Salmonella infection trend in a developing country during 1998-2007. Newly emerging rare Salmonella serovars should be traced and investigated to control new type pathogens in the developed world.

Vertebral Osteomyelitis due to Salmonella enterica serovar Othmarschen in an Immunocompetent Patient / 감염과화학요법

Salmonellae have been recognized as uncommon etiological organisms causing osteomyelitis in patients with sickle cell anemia and other immunocompromised conditions. A 34-year old man who had no underlying illness except for congenital block vertebrae at T10-11 vertebrae was admitted to the hospital due to lower back pain and fever for a week. Vertebral osteomyelitis was diagnosed and surgical drainage was performed. Salmonella enterica serovar Othmarschen was isolated from the drained pus. Therapy with ciprofloxacin for 8 weeks was successful without relapse. We describe here a case of vertebral osteomyelitis which was caused by S. Othmarschen in an immunocompetent patient.

Vertebral Osteomyelitis due to Salmonella enterica serovar Othmarschen in an Immunocompetent Patient / 감염과화학요법

Salmonellae have been recognized as uncommon etiological organisms causing osteomyelitis in patients with sickle cell anemia and other immunocompromised conditions. A 34-year old man who had no underlying illness except for congenital block vertebrae at T10-11 vertebrae was admitted to the hospital due to lower back pain and fever for a week. Vertebral osteomyelitis was diagnosed and surgical drainage was performed. Salmonella enterica serovar Othmarschen was isolated from the drained pus. Therapy with ciprofloxacin for 8 weeks was successful without relapse. We describe here a case of vertebral osteomyelitis which was caused by S. Othmarschen in an immunocompetent patient.

National Early Warning System Construction for Timely Surveillance of Foodborne Disease Outbreaks-PulseNet Korea / 감염과화학요법

Foodborne illnesses and big outbreaks have been increased because of the widespread of lunch distribution at school, mass production of food products, and international food trades. It is important to find the origin of contamination by various pathogens in an early stage of the outbreaks for the disease control and prevention. For the purpose of construction of the early warning system, Korea National Institute of Health (KNIH) inaugurated PulseNet Korea in 2005. The organization of PulseNet Korea consists of KNIH as a center and the participating laboratories including Korea Food & Drug Administration (KFDA), National Veterinary Research & Quarantine Station (NVRQS), and regional Institutes of Health & Environment. PulseNet Korea has focused on training researchers from participating laboratories as well as playing an important role in PulseNet International. In this review, PulseNet Korea construction is introduced as a national early warning system for timely surveillance of foodborne diseases.

National Early Warning System Construction for Timely Surveillance of Foodborne Disease Outbreaks-PulseNet Korea / 감염과화학요법

Foodborne illnesses and big outbreaks have been increased because of the widespread of lunch distribution at school, mass production of food products, and international food trades. It is important to find the origin of contamination by various pathogens in an early stage of the outbreaks for the disease control and prevention. For the purpose of construction of the early warning system, Korea National Institute of Health (KNIH) inaugurated PulseNet Korea in 2005. The organization of PulseNet Korea consists of KNIH as a center and the participating laboratories including Korea Food & Drug Administration (KFDA), National Veterinary Research & Quarantine Station (NVRQS), and regional Institutes of Health & Environment. PulseNet Korea has focused on training researchers from participating laboratories as well as playing an important role in PulseNet International. In this review, PulseNet Korea construction is introduced as a national early warning system for timely surveillance of foodborne diseases.

Prevalence of Salmonella Serovars Isolated from Domestic Residents and Overseas Travelers in Korea, 2004~2005

Salmonella is a communicable enteric pathogen commonly found in foodborne diseases. We showed the prevalence of S. enterica serovars from domestic residents and overseas travelers. In 2004-2005 years, Weltevreden, Anatum, and Tallahassee were predominant Salmonella serovars from overseas travelers, but Enteritidis, Typhimurium, and Typhi were major Salmonella serovars from domestic residents. In order to analyze the trends of prevalence and distribution of the serovars, Salmonella surveillance with an international study is essential for the disease control and prevention.

Rapid Serological Identification for Monophasic Salmonella Serovars with a hin Gene: Specific Polymerase Chain Reaction

Salmonellosis is one of the most common food born diseases in Korea. However, it takes more than 8 days and many expensive antiserums are used for the identification of Salmonella serovars since the microorganism easily undergoes phase variation. According to the data that 65.5% of Salmonella isolates in 2000~2004 year had monophasic flagella, we have developed a rapid serological identification method using a hin gene-specific polymerase chain reaction (PCR) for monophasic Salmonella isolates that does not require the time-consuming phase conversion experiments. Using our new method, 'hin specific PCR-based serological test', we could identify serovars of monophasic Salmonella in 4 days. For the purpose of rapid identification of salmonella serovars collected from outbreaks and sporadic cases, hin specific PCR-based serological tests will be a fast and efficient method.

Salmonella enterica Serovar London Infections Associated with Consumption of Infant Formula

Epidemiologic studies were conducted on 31 cases of Salmonella group E infection detected in 2000 through a laboratory-based pathogen surveillance in Gangwon Province, Korea. Data were collected on the environmental exposures and the patients' foods, including the brand (s) of milk consumed before the onset of diarrhea. The patients' medical records were also reviewed. All of the patients were infants under 10 months of age except one 7-year old child. Surprisingly, all of the infants were fed with infant formulas from Company A, although two infants were fed with infant formulas from both Company A and Company B. Antimicrobial susceptibility test and pulsed-field gel electrophoresis (PFGE) were performed in 25 out of 31 isolates from the patients and in 1 isolate from an opened packet of infant formula collected from the home of an infected infant. All of the 26 isolates were Salmonella enterica serovar London. They showed a single PFGE pattern, and all of the isolates were susceptible to the 18 antibiotics tested. The causative agent of the salmonella outbreaks in the Gangwon Province and its surrounding areas was Salmonella London, and the highly likely source of the infection was infant formula from Company A.

Epidemiology of Salmonella enterica Serotype Typhi Infections in Korea for Recent 9 Years: Trends of Antimicrobial Resistance

The aim of this study is to characterize the epidemiological features of typhoid fever, categorized as class 1 notifiable disease in Korea and to analyze the recent change of antimicrobial resistance of Salmonella enterica serotype Typhi isolated nationwide. We retrospectively analyzed the 1,692 culture-proven cases from 1992 to 2000, using the data of the Korean National Institute of Health. The overall incidence of culture-proven typhoid fever was 0.41 per 100,000 population. It occurred all over the country, but the southeastern part of Korean peninsula had the higher incidence rate than other areas. There were several outbreaks suspected, of which two outbreaks were confirmed. The resistance rate against chloramphenicol showed mild increase, but the ampicillin, trimethoprim/sulfamethoxazole, kanamycin, or nalidixic acid resistance remained at the similar levels for the past 9 yr. There were 21 (1.3%) multidrug-resistant (MDR) strains isolated since 1992, and the number of those has increased. Two strains resistant to ciprofloxacin were first identified in Korea.

Enteric Fever with Bowel Perforation Caused by Nontyphoidal Group D Salmonella / 감염과화학요법

The case of enteric fever and bowel perforation caused by nontyphoidal Salmonella spp. is extremely rare. We report a case of a 28-year-old man who suffered from enteric fever with complicated a small bowel perforation, which is a known complication of S. typhi and S. paratyphi infections. The culprit later proved to be nontyphoidal group D Salmonella spp. in our case.

Enteric Fever with Bowel Perforation Caused by Nontyphoidal Group D Salmonella / 감염과화학요법

The case of enteric fever and bowel perforation caused by nontyphoidal Salmonella spp. is extremely rare. We report a case of a 28-year-old man who suffered from enteric fever with complicated a small bowel perforation, which is a known complication of S. typhi and S. paratyphi infections. The culprit later proved to be nontyphoidal group D Salmonella spp. in our case.

A Virulent Strain of Salmonella enterica Serovar London Isolated in Infants with Enteritis Traced by Active Surveillance and Molecular Epidemiological Study

A total of 74 isolates of Salmonella enterica serovar London were collected through the Laboratory-Based Diarrheal Diseases Surveillance in 2000-2001. In order to characterize the isolates and investigate the source of the epidemic, we performed antimicrobial susceptibility tests and XbaI Pulsed-field gel electrophoresis (PFGE) of 44 Salmonella London isolates. Forty isolates were from feces of infants and four isolates were from adults aged 30, 52, 54, and 59 yr. Two subtypes were identified: a tetracycline-susceptible A 0 PFGE pattern and a tetracyclineresistant A 1 PFGE pattern. Interestingly, the isolates from all infants and one 30-yr-old adult were A 0 PFGE pattern and tetracycline-susceptible. Furthermore, the A 0 PFGE pattern strain was approximately 2 times more virulent than the A 1 PFGE pattern strain, according to the results of in vitro invasion assay using J774A.1 macrophage-like cells. These results indicate that the active surveillance with molecular epidemiological tools would be valuable for promptly finding new epidemic strains. Our results also suggested that the virulent Salmonella London strain might infect the infants through a common contaminated source.