BACKGROUND/AIMS: Methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) is a major bloodstream infection with a high mortality rate. Identification of factors associated with early mortality in MRSAB patients would be useful for predicting prognosis and developing new therapeutic options. METHODS: A prospective cohort of MRSAB patients was examined between August 2008 and June 2011. Early and late mortality was defined as death within 2 and 28 days of blood culture, respectively. The clinical and microbiological characteristics in the early and late mortality and survival groups were compared. Risk factors associated with severe sepsis or septic shock were also investigated. RESULTS: A total of 385 adult MRSAB patients whose S. aureus isolates were available were enrolled; of these patients, 25 patients (6.5%) and 50 (13%) died early and late, respectively. Compared with both the late-mortality group and the survival group, severe sepsis or septic shock was a statistically significant independent risk factor associated with early mortality. Rapidly or ultimately fatal McCabe and Jackson classification (adjusted odds ratio [aOR], 1.94; 95% confidence interval [CI], 1.25 to 3.02) and pneumonia (aOR, 2.04; 95% CI, 1.03 to 4.02) were independently associated with severe sepsis or septic shock. A vancomycin minimum inhibitory concentration (MIC) ≥ 1.5 μg/mL was associated with a reduced incidence of severe sepsis or septic shock (aOR, 0.53; 95% CI, 0.34 to 0.84). CONCLUSIONS: Severity of illness seems to be the most important risk factor associated with early mortality in MRSAB. Although vancomycin MIC was not independently associated with early mortality, reduced vancomycin susceptibility appears to be linked to reduced disease severity.
Adult ; Bacteremia* ; Classification ; Cohort Studies ; Humans ; Incidence ; Methicillin Resistance* ; Methicillin-Resistant Staphylococcus aureus* ; Microbial Sensitivity Tests ; Mortality* ; Odds Ratio ; Pneumonia ; Prognosis ; Prospective Studies ; Risk Factors ; Sepsis ; Shock, Septic ; Vancomycin

PURPOSE: To evaluate the efficacy of antibiotic-loaded cement spacers (ALCSs) for the treatment of diabetic foot infections with osteomyelitis as a salvage procedure and to analyze the risk factors of treatment failure. MATERIALS AND METHODS: This study reviewed retrospectively 39 cases of diabetic foot infections with osteomyelitis who underwent surgical treatment from 2009 to 2017. The mean age and follow-up period were 62±13 years and 19.2±23.3 months, respectively. Wounds were graded using the Wagner and Strauss classification. X-ray, magnetic resonance imaging (or bone scan) and deep tissue cultures were taken preoperatively to diagnose osteomyelitis. The ankle-brachial index, toe-brachial index (TBI), and current perception threshold were checked. Lower extremity angiography was performed and if necessary, percutaneous transluminal angioplasty was conducted preoperatively. As a surgical treatment, meticulous debridement, bone curettage, and ALCS placement were employed in all cases. Between six and eight weeks after surgery, ALCS removal and autogenous iliac bone graft were performed. The treatment was considered successful if the wounds had healed completely within three months without signs of infection and no additional amputation within six months. RESULTS: The treatment success rate was 82.1% (n=32); 12.8% (n=5) required additional amputation and 5.1% (n=2) showed delayed wound healing. Bacterial growth was confirmed in 82.1% (n=32) with methicillin-resistant Staphylococcus aureus being the most commonly identified strain (23.1%, n=9). The lesions were divided anatomically into four groups; the largest number was the toes: (1) toes (41.0%, n=16), (2) metatarsals (35.9%, n=14), (3) midfoot (5.1%, n=2), and (4) hindfoot (17.9%, n=7). A significant difference in the Strauss wound score and TBI was observed between the treatment success group and failure group. CONCLUSION: The insertion of ALCSs can be a useful treatment option in diabetic foot infections with osteomyelitis. Low scores in the Strauss classification and low TBI are risk factors of treatment failure.
Amputation ; Angiography ; Angioplasty ; Ankle Brachial Index ; Classification ; Curettage ; Debridement ; Diabetic Foot ; Follow-Up Studies ; Lower Extremity ; Magnetic Resonance Imaging ; Metatarsal Bones ; Methicillin-Resistant Staphylococcus aureus ; Osteomyelitis ; Retrospective Studies ; Risk Factors ; Toes ; Transplants ; Treatment Failure ; Wound Healing ; Wounds and Injuries

OBJECTIVES: The emergence of resistant bacteria is being increasingly reported around the world, potentially threatening millions of lives. Amongst resistant bacteria, methicillin-resistant Staphylococcus aureus (MRSA) is the most challenging to treat. This is due to emergent MRSA strains and less effective traditional antibiotic therapies to Staphylococcal infections. The use of bacteriophages (phages) against MRSA is a new, potential alternate therapy. In this study, morphology, genetic and protein structure of lytic phages against MRSA have been analysed. METHODS: Isolation of livestock and sewage bacteriophages were performed using 0.4 μm membrane filters. Plaque assays were used to determine phage quantification by double layer agar method. Pure plaques were then amplified for further characterization. Sulfate-polyacrylamide gel electrophoresis and random amplification of polymorphic DNA were run for protein evaluation, and genotyping respectively. Transmission electron microscope was also used to detect the structure and taxonomic classification of phage visually. RESULTS: Head and tail morphology of bacteriophages against MRSA were identified by transmission electron microscopy and assigned to the Siphoviridae family and the Caudovirales order. CONCLUSION: Bacteriophages are the most abundant microorganism on Earth and coexist with the bacterial population. They can destroy bacterial cells successfully and effectively. They cannot enter mammalian cells which saves the eukaryotic cells from lytic phage activity. In conclusion, phage therapy may have many potential applications in microbiology and human medicine with no side effect on eukaryotic cells.
Agar ; Bacteria ; Bacteriophages ; Caudovirales ; Classification ; DNA ; Electrophoresis ; Eukaryotic Cells ; Head ; Humans ; Livestock ; Membranes ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Methods ; Microscopy, Electron, Scanning Transmission ; Microscopy, Electron, Transmission ; Sewage ; Siphoviridae ; Staphylococcal Infections ; Tail

This study was conducted to determine the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs, farm workers, and the environment in northern Thailand, and to assess LA-MRSA isolate phenotypic characteristics. One hundred and four pig farms were randomly selected from the 21,152 in Chiang Mai and Lamphun provinces in 2012. Nasal and skin swab samples were collected from pigs and farm workers. Environmental swabs (pig stable floor, faucet, and feeder) were also collected. MRSA was identified by conventional bacterial culture technique, with results confirmed by multiplex PCR and multi locus sequence typing (MLST). Herd prevalence of MRSA was 9.61% (10 of 104 farms). Among pigs, workers, and farm environments, prevalence was 0.68% (two of 292 samples), 2.53% (seven of 276 samples), and 1.28% (four of 312 samples), respectively. Thirteen MRSA isolates (seven from workers, four from environmental samples, and two from pigs) were identified as Staphylococcal chromosomal cassette mec IV sequences type 9. Antimicrobial sensitivity tests found 100% of the MRSA isolates resistant to clindamycin, oxytetracycline, and tetracycline, while 100% were susceptible to cloxacillin and vancomycin. All possessed a multidrug-resistant phenotype. This is the first evidence of an LA-MRSA interrelationship among pigs, workers, and the farm environment in Thailand.
*Animal Husbandry ; Animals ; Cross-Sectional Studies ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/*genetics/*isolation & purification ; Microbial Sensitivity Tests/veterinary ; Molecular Sequence Data ; Multilocus Sequence Typing/veterinary ; Multiplex Polymerase Chain Reaction/veterinary ; Occupational Diseases/*epidemiology/microbiology ; Phylogeny ; Prevalence ; Sequence Analysis, DNA/veterinary ; Staphylococcal Infections/*epidemiology/microbiology ; Swine ; Swine Diseases/*epidemiology/microbiology ; Thailand/epidemiology

OBJECTIVETo study the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in children.

METHODA total of 37 MRSA strains were isolated from hospitalized patients in Children's Hospital of Fudan University from March 2009 to November 2011. The clinical characteristics were investigated by a cohort study. Furthermore, the mecA, Panton-Valentine leucocidin (PVL) genes were detected by polymerase chain reaction (PCR), and the genotypes of SCCmec were determined by multiplex PCR.

RESULT(1) Among the 37 MRSA isolates, infections with 21 were acquired from hospital (HA-MRSA), and 16 isolates were acquired from community (CA-MRSA). (2) In the study, MRSA frequently caused respiratory tract infection, and most of the strains were isolated from intensive care unit (ICU). (3) CA-MRSA was most frequently associated with skin and soft tissue infections (SSTI), suppurative tonsillitis, even pneumonia and septicemia. HA-MRSA infection was more aggressive, most frequently associated with pneumonia, septicemia, and central nervous system (CNS) infections, such as meningitis. In children with fever caused by HA-MRSA or CA-MRSA infection, HA-MRSA showed a longer duration of fever, for 10.5 days. C-reactive protein (CRP) level caused by HA-MRSA (63.00 mg/L) was higher than CA-MRSA (9.50 mg/L) , and there were statistically significant differences between the groups (t = 2.5670, P < 0.05). However, there were no statistically significant differences between the groups in white blood cell count (WBC) or procalcitonin (PCT) level. (4) Among 37 MRSA isolates, the whole isolates were mecA gene positive (100%). SCCmec genotyping results showed that the most frequent SCCmec types were type III, 17 isolates, the others including type IV 8 isolates, type II1 isolates, nontypable 11 isolates, type I and type V were not found in this group. Therein, among 21 HA-MRSA isolates, SCCmec III was the most common, 15 isolates, type IV 1 isolates, nontypable 5 isolates; among 16 CA-MRSA isolates, SCCmec type IV was the most common, 7 isolates, type III 2 isolates, type II 1 isolate, nontypable 6 isolates. (5) Among the 37 MRSA isolates, 28 were PVL gene positive; and among 21 HA-MRSA isolates, 17 were PVL gene positive; Among 16 CA-MRSA isolates, 11 were PVL gene positive; There were no statistically significant differences between the groups (χ(2) = 0.735, P > 0.05) .

CONCLUSIONCompared with CA-MRSA, HA-MRSA infection was more aggressive, and induced higher C reactive protein; the dominant epidemic strains of CA-MRSA was SCCmec type IV, and HA-MRSA was SCCmec type III; the positive rate of PVL gene was high.

Adolescent ; Anti-Bacterial Agents ; pharmacology ; Bacterial Proteins ; genetics ; Bacterial Toxins ; genetics ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; Cohort Studies ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; epidemiology ; microbiology ; DNA, Bacterial ; genetics ; Female ; Genotype ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin ; pharmacology ; Methicillin Resistance ; genetics ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Penicillin-Binding Proteins ; Staphylococcal Infections ; epidemiology ; microbiology

OBJECTIVETo develop a matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) approach to identify Staphylococcus aureus (S. aureus) and differentiate methicillin-resistant S. aureus (MRSA) from methicillin-sensitive S. aureus (MSSA).

METHODSA total of 100 S. aureus strains isolated from clinical specimens and farm workers were collected and analyzed by MALDI-TOF-MS. And data obtained were interpreted with biotyper software.

RESULTSNinety-two strains were identified by MALDI-TOF-MS as S. aureus at a level of secure genus and probable species, and 4 strains were identified at probable genus after their cultivation, spectral collection and data preprocessing. One strain was identified as S. aureus with lower score. It was revealed that identification of S. aureus by MALDI-TOF-MS was highly correlated with typing by biochemical and serological methods with an accuracy as high as 97%. The biotyper cluster analysis showed that 100 isolates were divided into 2 types at the distance level of 400. Higher peak intensity in the mass of both 3784 Da and 5700 Da was observed in MRSA, whereas that was absent from MSSA.

CONCLUSIONMALDI-TOF-MS is considered a simple, rapid and highly reproducible technique with high-throughput and accuracy for the identification of S. aureus and it can reliably differentiate MRSA from MSSA.

Anti-Bacterial Agents ; pharmacology ; Cluster Analysis ; Humans ; Methicillin ; pharmacology ; Methicillin Resistance ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; methods ; Staphylococcal Infections ; microbiology ; Staphylococcus aureus ; classification ; drug effects

No abstract available.
Aged, 80 and over ; Anti-Bacterial Agents/therapeutic use ; Community-Acquired Infections/diagnosis/*microbiology/therapy ; Debridement ; Drainage ; Female ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/genetics/*isolation & purification ; Microbial Sensitivity Tests ; Republic of Korea ; Staphylococcal Infections/diagnosis/*microbiology/therapy ; Treatment Outcome

BACKGROUND: Multiple-locus variable-number tandem-repeat fingerprinting (MLVF) is based on multiplex PCR, utilizing variable number tandem repeat. Our goal was to compare the performance of MLVF in distinguishing clinical Staphylococcus aureus isolates with that of pulsed-field gel electrophoresis (PFGE), which has traditionally been the gold standard. METHODS: Sixty-three clinically significant S. aureus isolates were tested using both PFGE and MLVF. Multiplex PCR for MLVF was performed using PCR primers for clfA, clfB, sdrCDE, sspA, and spa. PFGE was performed with genomic DNA fragments generated by SmaI endonuclease digestion. Banding patterns of MLVF or PFGE were analyzed using InfoQuestFP software. RESULTS: The hands-on time of our modified method was about 3 h, on average, for each of 18 isolates. PFGE (80% cutoff) or MLVF (75% cutoff) separated all of the 63 isolates into 13 and 12 types, respectively. Three types generated by PFGE were identical to those generated by MLVF. PFGE and MLVF yielded similar Simpson's diversity indices, indicating similar discriminatory power. The overall concordance between PFGE and MLVF was low, as represented by adjusted Rand indices (0.266-0.278). PFGE predicted MLVF type better than MLVF predicted PFGE type, as reflected by Wallace coefficients (PFGE cutoff 80% vs. MLVF cutoff 75%, 0.389 vs. 0.233). Analysis of the relationship between a pair of isolates showed 91.0% concordance between the PFGE (80% cutoff) and MLVF (75% cutoff). CONCLUSIONS: Our simple, low-cost, modified MLVF protocol can effectively discriminate between S. aureus clinical isolates. MLVF can replace PFGE for the hospital infection control of S. aureus.
Bacterial Typing Techniques/*methods ; *DNA Fingerprinting ; DNA, Bacterial/analysis ; *Electrophoresis, Gel, Pulsed-Field ; Genotype ; Humans ; Methicillin-Resistant Staphylococcus aureus/classification/genetics/isolation & purification ; Multiplex Polymerase Chain Reaction ; Staphylococcal Infections/*microbiology ; Staphylococcus aureus/*classification/*genetics/isolation & purification

OBJECTIVETo investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates from Chinese children in seven cities.

METHODA total of 134 MRSA isolates were collected from nine hospitals. Multilocus sequence typing and spa typing were analyzed by polymerase chain reaction (PCR), and staphylococcal chromosomal cassette mec (SCCmec) type was analyzed by multiplex PCR. The Panton-Valentine leukocidin (pvl) gene was also detected.

RESULTMost MRSA strains were isolated from pneumonia and skin and soft tissue infection (SSTIs) patients, accounting for 82.1%. Overall, 16 sequence types (STs) were obtained, and CC59 (51.7%) was found to be the most prevalent, which included ST 59 and ST 338, followed by ST239 (16.4%). SCCmec types II, III, IV, and V were also identified in the current study. SCCmec type IV was the most predominant type at 50.0%, followed by SCCmec type V at 23.9% and III at 23.9%. SCCmec subtypes IVa, IVc, and IVg were found among SCCmec type IV strains, whereas IVa was the main subtype at 77.6%. Twenty-six spa types were also identified, among which the predominant type was t437 (47.8%). The prevalence of pvl genes and the SCCmec type of strain was relevant, and the pvl gene positive rate was higher in SCCmec type IV and V-type strains than in SCCmec type II and III strains (58.6% vs. 14.3%, P < 0.05); there was a significant difference between them. In the strains isolated from pneumonia and SSTIs, ST59-MRSA-IVa(t437) was the predominant clone. There were five clones detected from the strains isolated from septicemia, with ST59-MRSA-IVa(t437) and ST59-MRSA-V(t437) as the main clones (57.1%). Various predominant clones existed in different regions. ST59-MRSA-IVa(t437) was the prevalent clone in the Guangzhou, Beijing, Chongqing, and Shenzhen areas, whereas ST239-MRSA-III(t037) was the prevalent clone in the Shanghai area. Fifty percent of the isolates from the Wenzhou area belonged to ST910-MRSA-V(t318), whereas three clinical strains isolated from the Shenyang region belonged to three different types.

CONCLUSIONThe results indicate that MRSA isolates from Chinese children are largely associated with the ST59-MRSA-IV(t437) and ST239-MRSA-III(t037) clones. These two may belong to community-acquired MRSA and hospital-acquired ones, respectively. Different prevalent clones were detected in different diseases and different regions. Therefore, there is a need to conduct further research on clinical isolates, which can guide the choice of antibiotic treatment and the examination of MRSA prevalence.

Adolescent ; Bacterial Typing Techniques ; Child ; Child, Preschool ; China ; epidemiology ; DNA, Bacterial ; genetics ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Methicillin-Resistant Staphylococcus aureus ; classification ; genetics ; isolation & purification ; Prevalence ; Staphylococcal Infections ; epidemiology ; microbiology

Panton-Valentine leukocidin (PVL)-positive USA300 clone has been the most successful community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clone spreading in North America. In contrast, PVL-negative ST72-CA-MRSA has been predominant in Korea, and there has been no report of infections by the USA300 strain except only one case report of perianal infection. Here, we describe the first case of pneumonia caused by the USA300 strain following pandemic influenza A (H1N1) in Korea. A 50-year-old man was admitted with fever and cough and chest radiograph showed pneumonic consolidation at the right lower lung zone. He received a ventilator support because of respiratory failure. PCR for pandemic influenza A (H1N1) in nasopharyngeal swab was positive, and culture of sputum and endotracheal aspirate grew MRSA. Typing of the isolate revealed that it was PVL-positive, ST 8-MRSA-SCCmec type IV. The analysis of the PFGE patterns showed that this isolate was the same pulsotype as the USA300 strain.
Community-Acquired Infections/*etiology/microbiology ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza, Human/*complications ; Male ; *Methicillin-Resistant Staphylococcus aureus/classification/isolation & purification ; Middle Aged ; Pneumonia, Staphylococcal/*etiology/microbiology ; Republic of Korea ; Staphylococcal Infections/*etiology/microbiology