Min-Hua Tseng

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.

Fatal sepsis and necrotizing pneumonia in a child due to community-acquired methicillin-resistant Staphylococcus aureus: Case report and literature review

Pediatric deaths due to community-acquired methicillin-resistant Staphylococcus aureus are rare. We describe the case of 2-y-old boy with fever and cough followed by comatose state with deteriorated respiration; the boy died of severe sepsis and necrotizing pneumonia. The etiological agent was community-acquired methicillin-resistant Staphylococcus aureus, carrying a type IV staphylococcal mecA gene cassette and the Panton-Valentine Leukocidin gene.

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.

Antimicrobial susceptibility of Staphylococcus aureus in children with atopic dermatitis.

Background:  Skin infection and/or nasal carriage of Staphylococcus aureus in children with atopic dermatitis (AD) is a risk factor for exacerbating disease or subsequent recurrent S. aureus infection. The purpose of the study is to evaluate the antibiotic susceptibilities of S. aureus strains from AD children and determine the most appropriate choice of antibiotics.

Comparative molecular analysis of meticillin-resistant Staphylococcus aureus isolates from children with atopic dermatitis and healthy subjects in Taiwan.

Background  Children with atopic dermatitis (AD) are more frequently colonized by Staphylococcus aureus than healthy children.

Panton-Valentine Leukocidin Is Associated with Exacerbated Skin Manifestations and Inflammatory Response in Children with Community-Associated Staphylococcal Scarlet Fever

BACKGROUND Staphylococcal scarlet fever (SSF), a rare disease, was first described in 1900. The clinical features and outcomes in children with SSF caused by Panton-Valentine leukocidin (PVL)-positive and PVL-negative Staphylococcus aureus strains have not been compared prospectively. METHODS The demographic data, selected clinical features, laboratory values, and outcomes for 49 consecutive children with community-acquired S. aureus SSF prospectively identified during an 11-year period were collected for analysis. RESULTS The male-to-female ratio was 1.88, and the median age of the patients was 37 months. Cutaneous abscesses predominated among children with SSF. Methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) caused SSF in 26 and 23 children, respectively. Twenty-four isolates had results that were positive for PVL (5 MSSA and 19 MRSA isolates), and 25 had results that were negative for PVL (21 MSSA and 4 MRSA isolates). Polymerase chain reaction revealed that most (92%) contained only staphylococcal enterotoxin B (23 MSSA and 22 MRSA isolates). By multivariate analysis, children with PVL-positive isolates had significantly larger abscess sizes, higher white blood cell counts, higher C-reactive protein levels, and longer durations of fever, generalized scarlatiniform rashes, and hospital stays. Most (17 isolates; 89%) of the 19 PVL-positive MRSA isolates carried the staphylococcal cassette chromosome mec V(T) and all were multilocus sequence type 59. CONCLUSION SSF caused by PVL-positive S. aureus strains were associated with more-exacerbated skin manifestations and a greater systemic inflammatory response, compared with those cases caused by PVL-negative S. aureus. Clinical improvement after incision and drainage was achieved for most children with SSF caused by PVL-positive MRSA strains, despite treatment with an ineffective antibiotic.

Fatal non-typeable Haemophilus influenzae sepsis complicated with acute respiratory distress syndrome : Case report and literature review

A previously healthy 31-month-old male child became acutely ill with dyspnea and high fever 48 h after admission for acute bronchitis. He experienced sepsis and acute respiratory distress syndrome throughout the subsequent hospitalization, eventually expiring despite aggressive treatment with antibiotics and extracorporeal membrane oxygenation. Blood cultures yielded ampicillin-resistant non-typeable Haemophilus influenzae. To the best of our knowledge, this is the first reported case of fatal non-typeable H. influenzae sepsis and ARDS in a child without an underlying predisposing condition.

Chilaiditi's syndrome in a 9-year-old girl with hepato-diaphragmatic interposition of the colon: a short report.

Chilaiditi’s syndrome is an infrequent condition with radiological evidence of symptomatic colonic interposition between the liver and diaphragm. We report on a 9-year-old girl suffering from this rare syndrome and on the predisposing factors of diaphragmatic eventration and constipation which would also appear to be rare and may never have been reported previously for children. A 9-year-old girl was admitted to our hospital complaining of a 4-day history of epigastric pain, constipation, and nausea without preceding trauma. The patient was haemodynamically stable and had a low-grade fever. Upon examination, slightly decreased breath sounds were noted at the right lung base, compared with the left. Tympany and hyperactive bowel sounds were present in the right abdomen, which was diffusely tender off and on without rebound. There was no hyperleukocytosis and there were no other abnormalities apparent upon clinical examination. On an X-ray film, the colon was found between the right liver surface and the diaphragm (Fig. 1A,B). The patient passed a lot of gas and hard dry stools with the help of an enema; however, the symptoms did not resolve until after nasogastric decompression and parenteral electrolyte solution administration over the subsequent 5 days. The incidence of Chilaiditi’s syndrome in the general population ranges from 0.025% to 0.28% and seems to increase with age [5]. The sex ratio is 4:1, male to female [2]. The syndrome is usually of little clinical significance, but nausea, vomiting, anorexia, constipation, right upper quadrant pain, and epigastric pain have been described [2,5]. Aetiologically, Chilaiditi’s syndrome has been attributed to either intestinal factors, diaphragmatic factors, hepatic factors, an enlarged lower thoracic outlet or elevated intra-abdominal pressure [2, 4,5]. In this patient, constipation is likely a significant contributor to colonic mobility, given its reported association with colonic elongation. Furthermore, diaphragmatic eventration provides a larger potential suprahepatic space which could lead to colonic interposition [4]. The ascent of the distended colon is such that it can protrude into the subphrenic space with frequently consequent infero-medial displacement of the liver [6]. Our patient, however, presented with an upward and medial displacement of the liver, associated with diaphragmatic eventration.

Dissemination of Methicillin-resistant Staphylococcus aureus among Healthy Children in Northern Taiwan

Background: We previously reported the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections among children in Taiwan was increasing. This study examined the extent of MRSA colonization in the healthy pediatric population existed in parallel with this trend. Method: In this prospective observational study, nasal swabs were obtained from healthy children presenting for child healthcare visits or attending one of seven kindergartens during a 2-year period. A case-control study and molecular typing studies were performed. Results: Of 1195 children, 89 (7.4%) had nares cultures positive for MRSA. Risk factors for MRSA colonization included household contact with a high-risk individual (odds ratio [OR], 8.971; 95% confi dence interval [CI], 2.968-27.117) and recent antibiotic use (OR, 5.997; 95% CI, 3.605-9.976). Staphylococcal cassette chromosome mec (SCCmec) typing showed most community MRSA strains were SCCmec types IV and type V(subscript T). Pulsed-field gel electrophoresis revealed MRSA clones distinct from nosocomial MRSA isolates have disseminated in healthy children, and Panton-Valentine leukocidin genes were present in 15 of 89 MRSA isolates (16.9%). Conclusions: As colonization typically precedes infection, the characteristics of children with MRSA nasal carriage may be useful for distinguishing those who may be at risk of MRSA infection.