This article reviews the advance in the research of both the mechanism of photodynamic antimicrobial chemotherapy (PACT) based on the principle of photodynamic therapy and the application of PACT in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection. Nowadays an inexorable prevalence of resistant bacteria observed worldwide, among which MRSA strains typically have a high potential of provoking outbreaks with intractability, makes it a pressing issue to develop new germicidal strategies. PACT is an emerging photochemistry-based technology. In the presence of oxygen, PACT, with the aid of the activation of photosensitizers to generate reactive oxygen species by the wavelength-specific light, destroys the structure of bacteria selectively and efficiently, with much lower bacterial resistance level than that of antibiotics. We expect that further research would elucidate the mechanism and develop clinical applications of PACT, and it may become a novel approach to solve the problem of MRSA infection in the future.
Methicillin-Resistant Staphylococcus aureus ; Photochemotherapy ; Staphylococcal Infections ; microbiology ; therapy

OBJECTIVETo observe the biofilm (BF) formation of Staphylococcus aureus (SA), Acinetobacter baumannii (AB) and Pseudomonas aeruginosa (PA) on the surface of deep vein catheters in burn patients after infection.

METHODSThe bacteria from deep vein catheters in 20 patients hospitalized from November 2008 to August 2009 were isolated, and were compared with their respective standard stains. Catheters tips were examined with scanning electron microscope (SEM). The semi-quantitative adhesion assay of bacterial BF was performed with modified microtiter-plate test, and the thickness of BF was scanned and measured by confocal laser scanning microscopy (CLSM) after double fluorescence staining, after being cultured in vitro for 12, 24, 48, 72 hours and 5 days, respectively. Data were processed with grouped t test.

RESULTSSix strains of SA, 8 strains of AB, and 6 strains of PA, all drug resistant, were isolated from the deep vein catheters. SEM showed that the BF structures on the inner surfaces of catheters were in diverse in their shape and degree, characterized by adherence and flake formation, and embedded in polysaccharide matrix. BF gathered in clusters, forming three-dimensional structure, in which small amount of red blood cells were found. A small number of bacteria were incompletely embedded, with some bacteria adhered to them. The absorbance values for SA after 24, 48 and 72 hours of culture (PCH) were above the cut-off value, the same for AB at PCH 12, 24, 48 and 72, and PA after PCH 48. Except for PA standard strain, CLSM showed scattered green fluorescence, mainly close to the bottom of plate, while the red fluorescence was observed in full scope at PCH 24 for each strain. At PCH 48 green fluorescence increased obviously and extended upward from the bottom, overlapping partly with red fluorescence, forming yellow fluorescence, and among the bacteria it was most obvious in AB culture, with SA the next. Compared with those of the standard stains, the intensity and quantity of fluorescence from the clinical strains were stronger; at PCH 72 the green fluorescence increased obviously especially for PA and its standard strain, while the yellow fluorescence was full of the scope for other strains. On in vitro culture day 5, the green fluorescence was dispersed and was obvious on the bottom of the plate. BF mature time for AB and SA was PCH 48, and for PA was PCH 72. The BF thickness of AB was (18.2 +/- 3.6) microm at PCH 72, which was thicker than that [(9.4 +/- 2.6) microm] of its standard strain (t = 5.42, P < 0.05), and was also the thickest among the three clinically found strains.

CONCLUSIONSSA, AB and PA, which are commonly found bacteria in burn patients, can form BF in deep vein catheters. Their ability to form BF seems to be stronger than other usually pathogenic strains, especially AB, which is the important pathogen leading to catheter related infection.

Acinetobacter Infections ; microbiology ; Acinetobacter baumannii ; growth & development ; Bacterial Adhesion ; Biofilms ; Burns ; microbiology ; Catheters ; microbiology ; Humans ; Pseudomonas Infections ; microbiology ; Pseudomonas aeruginosa ; growth & development ; Staphylococcal Infections ; microbiology ; Veins ; microbiology

China ; Cross Infection ; microbiology ; prevention & control ; Enterobacteriaceae Infections ; Escherichia coli Infections ; Female ; Hospitalization ; Humans ; Male ; Microbial Sensitivity Tests ; Respiratory Tract Infections ; microbiology ; Staphylococcal Infections ; Wound Infection ; microbiology

Mural endocarditis causing myocardial abscess without valvular involvement is very rare. We report an unusual case of left atrial auricular abscess which was successfully treated by surgical resection, treatment with antibiotics, and mediastinal irrigation. A 9-yr-old female patient with previous history of urinary tract infection was admitted because of persistent fever. Echocardiography and magnetic resonance imaging revealed massive pericardial effusion and a mass lesion at the left upper cardiac border. Pericardiocentesis isolated Staphylococcus aureus on culture. The patient underwent mass removal under cardiopulmonary bypass. The mass was located in the left atrial auricle with fibropurulent abscess formation inside. Postoperative mediastinal irrigation was performed using povidone iodine solution. Pathological examination of the mass showed organized thrombi with chronic fibrosing mural endocarditis.
Abscess/microbiology/pathology/*surgery ; Child ; Endocarditis/microbiology/pathology/*surgery ; Female ; Heart Atria/microbiology/pathology ; Human ; Staphylococcal Infections/pathology/*surgery

Methicillin resistant Staphylococcal aureus (MRSA) enterocolitis is characterized by high fever, abdominal distension, and watery diarrhea that leads to severe dehydration, shock, a sharp decrease in the white cell counts and sometimes multiple organ failure. Clinically, it can be an another cause of nosocomial diarrhea. If MRSA enteritis is suspected from the clinical symptoms, prompt treatment and strict prophylactic measures including vancomycin, are most important for its management. We recently observed a case of MRSA enterocolitis as a nosocomial infection in a patient with acute pancreatitis. This patient showed uncontrolled massive diarrhea, fever, and multiple organ failure. We report a case of MRSA enterocolitis with a review of literatures.
Cross Infection/diagnosis/*microbiology ; Diarrhea/etiology/*microbiology ; Enterocolitis/complications/diagnosis/*microbiology ; Humans ; Male ; *Methicillin Resistance ; Middle Aged ; *Staphylococcal Infections/diagnosis

No abstract available.
Catheter-Related Infections/*microbiology ; Catheters, Indwelling/*adverse effects ; Female ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/*isolation & purification ; Staphylococcal Infections/*microbiology

OBJECTIVETo study the proteomic change in lymphocytes of rabbits with scald injury and Staphylococcus aureus (SA) invasion.

METHODSTwenty-four rabbits were divided into four groups as follows: control group, scald group, scald with SA invasion 2 hs group, and scald with SA invasion 6 hs group, according to random number table, with 6 rabbits in each group. Except for rabbits in control group (sham scald at 37 degrees C), rabbits in the other 3 groups were subjected to 30% TBSA full-thickness scald. Rabbits in SA invasion 2 and 6 hs groups were injected with 2 mL (1.0 x 10(8) CFU/mL) SA suspension, which was in the log growth phase, via auricle vein 18 hs and 22 hs after injury. Whole blood samples were collected from carotid artery of rabbits in 4 groups 24 hs after scald. Lymphocytes were isolated and its extracted proteins were analyzed by two-dimensional gel electrophoresis coupled with mass spectroscopy.

RESULTSAbout 1030 protein spots of lymphocytes were detected in each group. Compared with that of control group, 19 protein spots were found to be differentially expressed in the other 3 groups, and 11 spots (10 proteins) were identified. Expression levels of cofilin, cyclophilin A, ubiquitin, nucleoside diphosphate kinase, glutamate dehydrogenase and annexin 1 were down-regulated, but expression level of peroxiredoxin was up-regulated obviously.

CONCLUSIONSThere is obvious proteomic change in lymphocytes of scalded rabbits or of scalded rabbits invaded by SA, and it may relate to immune suppression and sepsis after injury.

Animals ; Burns ; metabolism ; microbiology ; Lymphocytes ; metabolism ; Male ; Proteome ; Rabbits ; Staphylococcal Infections ; etiology ; metabolism

INTRODUCTIONCommunity-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged worldwide. In contrast to healthcare-associated MRSA (HA-MRSA), CA-MRSA isolates are usually susceptible to multiple non-beta-lactam antibiotics and cause a distinct spectrum of infections in epidemiologically disparate populations - in particular, cutaneous abscesses, necrotising fasciitis and necrotising pneumonia. They arise from a broader genetic background, and possess differing virulence genes. We aim to describe the distribution of different molecular subtypes of CA-MRSA among various regions and discuss briefly the implications of CA-MRSA from a local perspective.

METHODSLiterature review of articles on CA-MRSA, focusing mainly on reports where the genetic background of isolates had been analysed using multi-locus sequence typing (MLST). Singapore data were obtained from the local CA-MRSA database.

RESULTSMLST analysis demonstrated the presence of epidemic subtypes of CA-MRSA within most geographic areas. In parts of the United States, community MRSA infections currently exceed those caused by their methicillin-susceptible counterparts. In Singapore, CA-MRSA infections are increasing, predominantly as a result of the spread of ST30 clones.

CONCLUSIONAvailable evidence suggests that the emergence of MRSA from the community is not going to be a transient phenomenon. Local guidelines for dealing with this phenomenon at both therapeutic and preventive levels are needed prior to the potential development of a situation mirroring that of meso-endemic HA-MRSA in local hospitals or CA-MRSA epidemics in parts of USA.

Bacterial Typing Techniques ; Community-Acquired Infections ; epidemiology ; microbiology ; Cross Infection ; diagnosis ; microbiology ; Humans ; Methicillin Resistance ; Risk Factors ; Singapore ; epidemiology ; Staphylococcal Infections ; epidemiology ; microbiology ; Staphylococcus aureus ; classification ; drug effects

Child ; Community-Acquired Infections ; complications ; microbiology ; Epidural Abscess ; diagnostic imaging ; etiology ; microbiology ; Female ; Humans ; Magnetic Resonance Imaging ; Methicillin-Resistant Staphylococcus aureus ; pathogenicity ; Staphylococcal Infections ; complications ; microbiology

OBJECTIVETo establish a guinea pig model of tympanosclerosis and investigate the development and progression of tympanosclerosis in the tympanic membranes and middle ear mucosa.

METHODSTwenty-one healthy guinea pigs were subjected inoculation of 1x10(8)/L Staphylococcus aureus into the left middle ear cavities under general anaesthesia, with the right ears as the control, to establish models of chronic purulent otitis media. The animals were sacrificed by decapitation after 1, 3 and 6 months after model establishment for histological examination of the middle ear mucosa.

RESULTSThe histological changes of tympanosclerosis occurred in some of the animals 3 months after model establishment, and the extent of calcium deposition and fibrosis across the mucosa were positively correlated with the duration of chronic purulent otitis media.

CONCLUSIONTympanosclerosis may occur in some guinea pigs after inoculation of Staphylococcus aureus into the middle ear cavity, and this model can be useful for study of tympanosclerosis.

Animals ; Disease Models, Animal ; Ear, Middle ; microbiology ; pathology ; Guinea Pigs ; Otitis Media with Effusion ; microbiology ; pathology ; Sclerosis ; microbiology ; pathology ; Staphylococcal Infections ; pathology ; Tympanic Membrane ; microbiology ; pathology