Mong-Ling Chu

Epidemiological Typing of Community-Acquired Methicillin-Resistant Staphylococcus aureus Isolates from Children in Taiwan

BACKGROUNDnA 1400-bed tertiary medical center in northern Taiwan was used to conduct an epidemiological study of children hospitalized with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection during a 5-year period.nnnMETHODSnNineteen previously healthy children with predominantly skin and soft-tissue CA-MRSA infections were enrolled into the study. Seventeen CA-MRSA isolates were examined for antimicrobial susceptibility and molecular typing.nnnRESULTSnA comparison of our results with the reported resistance rates among CA-MRSA isolates from other countries showed uniformly high macrolide resistance (100%). Of the 17 MRSA isolates in our study, all had the macrolide-lincosamide-streptogramin-constitutive phenotype and the ermB gene. Moreover, on the basis of molecular typing results, 11 (65%) of 17 CA-MRSA isolates were genetically related (as determined by pulsed-field gel electrophoresis), and multilocus sequence typing revealed a sequence type of 59 in all isolates. Staphylococcal toxin genes lukS-PV and lukF-PV were detected in all isolates. However, staphylococcal cassette chromosome mec type IV was only detected in 3 (17.6%) of 17 isolates; the remaining 14 isolates were untypeable.nnnCONCLUSIONSnAnalysis of our data suggests the predominance of a single endemic CA-MRSA strain with high macrolide resistance in our community. Clinical improvement with incision and drainage was noted for most patients, despite treatment with an ineffective antibiotic, so the need for a change in treatment guidelines should be addressed.

Nasal carriage of a single clone of community-acquired methicillin-resistant Staphylococcus aureus among kindergarten attendees in northern Taiwan

Background:To evaluate the prevalence and microbiological characterization of community-acquired (CA) methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage in a kindergarten.Methods:Point prevalence study. Nasal swabs were collected from healthy children younger than 7 years of age who were attending a kindergarten in Taipei, Taiwan. A parent questionnaire regarding MRSA risk factors was administered simultaneously. All CA-MRSA colonization isolates were archived for subsequent antimicrobial susceptibility and molecular typing.Results:Of the 68 children who participated in the study, 17 (25%) had S. aureus isolated from nasal swabs. Nine (13.2%) of the 68 children had CA-MRSA carriage, and none of them had any identified risk factors. Antimicrobial susceptibility testing revealed all of the 9 CA-MRSA colonization isolates had uniformly high resistance (100%) to both clindamycin and erythromycin, the macrolide-lincosamide-streptogramin-constitutive phenotype and the ermB gene. Pulsed-field gel electrophoresis revealed 8 (88.9%) of 9 CA-MRSA colonization isolates were genetically related and multilocus sequence typing revealed all isolates had sequence type 59. All of the colonization isolates carried the staphylococcal cassette chromosome mec type IV, but none were positive for the Panton-Valentine leukocidin genes.Conclusion:The results of this study suggest that a single predominant CA-MRSA colonization strain featuring high clindamycin resistance circulated in this kindergarten. Additionally, due to the established transmissibility of colonization isolates, the high prevalence of nasal carriage of CA-MRSA among healthy attendees in kindergartens may indicate the accelerated spread of CA-MRSA in the community.

Community-acquired Methicillin-resistant Staphylococcus aureus in Children, Taiwan

Highly virulent community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) with Panton-Valentine leukocidin (PVL) is common worldwide. Using antimicrobial drug susceptibility testing, staphylococcal cassette chromosome mec typing, exotoxin profiling, and pulsed-field gel electrophoresis typing, we provide evidence that supports the relationship between nasal strains of PVL-positive MRSA and community-acquired disease.

Risk factors and molecular analysis of panton-valentine leukocidin-positive methicillin-resistant Staphylococcus aureus colonization in healthy children.

Background: Nasal carriage of Panton-Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) is associated with community associated disease. The risk factors for and characteristics of PVL-positive MRSA colonization in the healthy pediatric population are not well understood. Methods: Anterior nares cultures were obtained from healthy children ≤14 years of age presenting for health maintenance visits or attending 1 of 8 kindergartens during a 3-year period. A case-control study and molecular typing studies were performed. Results: A total of 131 (8.1%) of 1615 children had nares cultures positive for MRSA, and 25 (1.5%) were colonized with PVL-positive MRSA. Nasal colonization of PVL-positive MRSA was significantly higher in 2006 than in 2004 (2.8% versus 0.7%; P = 0.006). By multivariate analysis, antibiotic use during the past 12 months (odds ratio, 29.37; 95% confidence interval, 10.72–80.50; P < 0.001) was the major risk factor associated with PVL-positive MRSA colonization in healthy children. Comparison of hospital MRSA strains with the community colonization strains by antimicrobial susceptibility testing, macrolide-lincosamide-streptogramin resistance gene testing, staphylococcal cassette chromosome mec typing, exotoxin profiling, and pulsed-field gel electrophoresis typing revealed that clonal spread of PVL-positive MRSA distinct from clinical hospital strains contributed to the high PVL-positive MRSA burden in the community. Conclusions: Nasal PVL-positive MRSA colonization in healthy children with no relationship to the hospital setting has increased significantly in the past 3 years, suggesting that it may be a major factor in the emergence of community-acquired MRSA disease in Taiwan. Previous antibiotic use was associated with PVL-positive MRSA colonization.

The effectiveness of single and multiple applications of triple dye on umbilical cord separation time

Abstract The effectiveness of single and multiple applications of triple dye for umbilical cord care in the umbilical cord separation time (UCST) was evaluated in 180 neonates. Seven neonates were excluded, three where the cord stump separation time was uncertain and four to whom contact was lost. The participating neonates were randomly assigned to two groups. Group 1, 101 neonates, were treated with a regimen of a single application of triple dye. Group 2, 79 neonates, were treated with multiple applications of triple dye. Complete information was obtained from 97 neonates (96.2%) in group 1 and 76 (96%) in group 2. The UCST was 12.6u2009±u20090.45 (meanu2009±u2009SE) days in group 1 and 16.68u2009±u20090.65 days in group 2 (Pu2009<u20090.0001) and showed no significant association with infants gender, mode of delivery, gravidity, gestational age, birth weight, or hospital stay.nConclusion A single application of triple dye may be a more favourable regimen with a similarly antimicrobial effect, a shorter UCST and may be more cost effective than multiple applications of triple dye in umbilical cord care.

Extensive necrotising fasciitis caused by Pseudomonas aeruginosa in a child with acute myeloid leukaemia: case report and literature review

This case report describes necrotising fasciitis (NF) caused by Pseudomonas aeruginosa obtained from an extensive haemorrhagic area of the face in a boy during the granulocytopenic phase of induction chemotherapy for acute myeloid leukaemia (AML), with a survey of the literature of paediatric cases of NF involving P. aeruginosa. A 13-year-old boy suffering from AML underwent induction chemotherapy (daunomycin and cytarabine), with the hospital course complicated by severe mouth pain on the 10th day of chemotherapy. A diffuse white exudate was noted on his buccal mucosa and posterior pharynx, with some palpable submandibular nodes. Throat cultures subsequently yielded P. aeruginosa. Two days later, fever developed along with bilateral facial swelling and extreme tenderness of the area, especially on the left side (Fig. 1A,B). Neither non-steroidal antiinflammatory drugs (NSAIDs) nor seafood was given before onset of the symptoms. Laboratory studies disclosed a platelet count of 6,000/mm and the white blood cell count was 100/mm, with 25% segmented neutrophils. An MRI scan of the lesion showed fascial-layer irregularity and thickening of the subcutaneous tissue without any loculate abscess, consistent with the early findings in NF. Incision, debridement and fasciotomies were performed, followed by meticulous wound care. On the 3rd day after surgery, P. aeruginosa was found in all wound tissues. Based on the available in vitro susceptibility data, broad-spectrum antibiotics, including ceftazidime and gentamicin, were continued for a total of 21 days. Concomitant adjuvant therapy, including administration of granulocyte colony-stimulating factor (G-CSF; 5 lg/kg; Filgrastim, Kirin) and intravenous hyperalimentation, were also given. Eventually, the wound closed after several minor debridements. After full recovery, the boy was transferred to another tertiary care institution to receive bone marrow transplantation 117 days after admission. NF due to P. aeruginosa infection is extremely rare. To our knowledge, only two paediatric cases have been reported to date [3,4], both of which had acute lymphoblastic leukaemia (ALL) as the underlying disease with the site of entry thought to be local trauma and decubitus ulcers. Although, in our patient, the mode of transmission was not established, respiratory colonisation proved by positive throat cultures was presumed to be the most probable source of infection because disruption of the mucocutaneous barriers appeared to have occurred concurrently. Predisposing factors associated with the use of NSAIDs [6] and ingestion of seafood [1] were not identified as these could increase the risk of NF. The reports in the literature are unanimous in their emphasis on the initial role of early surgical intervention Fig. 1 A Rapid progression of facial oedema, especially on the left side. Onset of haemorrhagic necrosis is evident in the left face, cheek and mouth, with the latter open involuntarily due to perioral oedema. B Within 12 h, there was a rapid progression of the NF lesion with massive oedema, obvious cutaneous gangrene, and oozing of blood from the affected area

Kinetic Th1/Th2 responses of transgenic mice with bacterial meningitis induced by Haemophilus influenzae

To investigate the kinetic Th1/Th2 immunopathogenic mechanisms of Haemophilus influenzae meningitis, we established a murine experimental model of meningitis and elucidated the Th1/Th2 immune responses in T1/T2 doubly transgenic mice based on a BALB/c background under the control of the IFN-gamma (interferon-gamma)/IL-4 (interleukin-4) promoters respectively. NTHi (non-typeable Haemophilus influenzae) meningitis was induced in these mice by inoculation with either a colonized (CNTHi) or invasive (INTHi) strain of NTHi. Mice inoculated with CNTHi displayed a less severe degree of disease in terms of clinical symptoms, mortality rate and brain histopathology. Conversely, INTHi-inoculated mice had more severe clinical symptoms. CNTHi-inoculated mice had a more significant Th1 response in terms of a higher percentage and longer maintenance of Th1 cells, and more production of IFN-gamma from strain-specific antigen-stimulated splenocytes than INTHi-inoculated mice. In contrast, INTHi-inoculated mice had a more significant Th2 response. This was due to a significant increase in IL-4-producing CD4(+) T-cells (Th2 cells) and more production of IL-4 from strain-specific antigen-stimulated splenocytes accompanied by a rapid decline of Th1 cells in INTHi-inoculated mice. In conclusion, the preferential Th1/Th2 trend in this murine model of NTHi meningitis is correlated with clinical severity as well as isolated characteristics of the pathogens themselves.