Predominance and Emergence of Clones of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus in Malaysia

We define the epidemiology of predominant and sporadic methicillin-resistant Staphylococcus aureus (MRSA) strains in a central teaching and referral hospital in Kuala Lumpur, Malaysia. This is done on the basis of spa sequencing, multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and virulence gene profiling. During the period of study, the MRSA prevalence was 44.1%, and 389 MRSA strains were included. The prevalence of MRSA was found to be significantly higher in the patients of Indian ethnicity (P < 0.001). The majority (92.5%) of the isolates belonged to ST-239, spa type t037, and possessed the type III or IIIA SCCmec. The arginine catabolic mobile element (ACME) arcA gene was detected in three (1.05%) ST-239 isolates. We report the first identification of ACME arcA gene-positive ST-239. Apart from this predominant clone, six (1.5%) isolates of ST-22, with two related spa types (t032 and t4184) and a singleton (t3213), carrying type IVh SCCmec, were detected for the first time in Asia. A limited number of community-acquired (CA) MRSA strains were also detected. These included ST-188/t189 (2.1%), ST-1/t127 (2.3%), and ST-7/t091 (1%). Panton-Valentin leukocidin (PVL) was detected in all ST-1 and ST-188 strains and in 0.7% of the ST-239 isolates. The majority of the isolates carried agr I, except that ST-1 strains were agr III positive. Virulence genes seg and sei were seen only among ST-22 isolates. In conclusion, current results revealed the predominance of ST-239-SCCmec III/IIIA and the penetration of ST-22 with different virulence gene profiles. The emergence in Malaysia of novel clones of known epidemic and pathogenic potential should be taken seriously.Methicillin-resistant Staphylococcus aureus (MRSA) is an established human pathogen that causes both health care-associated (HA) and community-acquired (CA) infections. Modern MRSA has evolved from several successful clonal lineages of methicillin-susceptible S. aureus strains via acquisition of a mobile genetic element called staphylococcal cassette chromosome mec (SCCmec). This element contains the mecA gene, which encodes penicillin-binding protein 2′ (PBP2′) with significantly reduced affinity for β-lactams (36).Increased emergence of multidrug resistance among MRSA strains has become a major concern in the hospital environment, as it invokes a tremendous financial burden and enhanced morbidity and mortality due to hard-to-treat systemic infections (7). Genotyping data from large international studies have shown that a limited number of major clones of MRSA display an enhanced propensity to spread and cause opportunistic human infections in various parts of the world (5, 13, 33). MRSA was introduced into Malaysia in the early 1970s (26), and a review of the records of the microbiology laboratories of all state hospitals in Malaysia showed that the proportion of MRSA isolates from S. aureus-infected individuals had been approximately 21% throughout the last few years.Phenotypic MRSA typing methods are not suited to detailed epidemiological surveillance (20, 40). Several superior molecular typing methods can be used for supporting infection control and for tracing the nosocomial sources and transmission routes of bacterial pathogens. Among these methods, multilocus sequence typing (MLST) has recently been proven to be the best for long-term global epidemiological and bacterial population genetics studies. It is a discriminatory genotypic method where isolates are typed by sequencing variable regions of housekeeping genes. A combination of alleles from the seven loci forms a sequence type (ST). Similar STs are grouped into clonal complexes (13). spa typing has been shown to be as discriminatory as the current gold standard method, pulsed-field gel electrophoresis (PFGE) (10). spa types can be determined via amplification and sequencing of the X region of the protein A gene (spa), which contains polymorphic direct repeats. StaphType (version 1.4; Ridom GmbH, Würzburg, Germany) provides a software tool enabling straightforward sequence analysis and designation of spa types by synchronization via a central server (42). spa typing is useful in analyzing hospital outbreaks and in identifying genetic changes that occur over a relatively short time span (14, 43). Molecular typing data on HA MRSA isolates in Malaysia are sparse in comparison with those on strains deriving from Europe, the United States, or Japan. This is notwithstanding the steadily increasing but already high rates of MRSA infections in Malaysia (38). Pilot data hinted at the predominance of a single MRSA genotype in Malaysia. This is similar to the situation in many other Asian countries (1, 23, 31).For the present study, clinical MRSA isolates associated with various infections were collected from the largest public tertiary referral hospital in Kuala Lumpur, the capital of Malaysia. The epidemiology of MRSA in this hospital (HKL) will most likely reflect the nation''s epidemiology as it is the major government referral hospital for patients from all states in Malaysia. Each year at least 1 million people (∼3.8% of the total Malaysian population) are treated here. HKL records an annual MRSA prevalence over 40%. Many of these MRSA strains are multidrug resistant. Additional epidemiological studies are clearly warranted in order to increase the insight into the dynamics of MRSA epidemiology in Malaysia.The aims of the present study were to characterize the current Malaysian MRSA isolates and determine their molecular epidemiology by MLST, spa typing, SCCmec typing, and virulence gene profiling.     

Autoinflammatory diseases in childhood,part 1: monogenic syndromes

Autoinflammatory diseases constitute a family of disorders defined by aberrant stimulation of inflammatory pathways without involving antigen-directed autoimmunity. They may be divided into monogenic and polygenic types. Monogenic autoinflammatory syndromes are those with identified genetic mutations, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic fever syndrome (TRAPS), mevalonate kinase deficiency or hyperimmunoglobulin D syndrome, cryopyrin-associated periodic fever syndromes (CAPS), pyogenic arthritis pyoderma gangrenosum and acne (PAPA) syndrome, interleukin-10 and interleukin-10 receptor deficiencies, adenosine deaminase 2 deficiency and pediatric sarcoidosis. Those without an identified genetic mutation are known as polygenic and include systemic-onset juvenile idiopathic arthritis, idiopathic recurrent acute pericarditis, Behçet syndrome, chronic recurrent multifocal osteomyelitis and inflammatory bowel disease among others. Autoinflammatory disorders are defined by repeating episodes or persistent fever, rash, serositis, lymphadenopathy, arthritis and increased acute phase reactants, and thus may mimic infections clinically. Most monogenic autoinflammatory syndromes present in childhood. However, because of their infrequency, diverse and nonspecific presentation, and the relatively new genetic recognition, diagnosis is usually delayed. In this article, which is Part 1 of a two-part series, the authors update monogenic autoinflammatory diseases in children with special emphasis on imaging features that may help establish the correct diagnosis.

     

Current status and implications of microRNAs in ovarian cancer diagnosis and therapy

Ovarian cancer is the fifth most common cancer among women and causes more deaths than any other type of female reproductive cancer. Currently, treatment of ovarian cancer is based on the combination of surgery and chemotherapy. While recurrent ovarian cancer responds to additional chemotherapy treatments, the progression-free interval becomes shorter after each cycle, as chemo-resistance increases until the disease becomes incurable. There is, therefore, a strong need for prognostic and predictive markers to help optimize and personalize treatment in order to improve the outcome of ovarian cancer. An increasing number of studies indicate an essential role for microRNAs in ovarian cancer progression and chemo-resistance. MicroRNAs (miRNAs) are small endogenous non-coding RNAs (~22bp) which are frequently dysregulated in cancer. Typically, miRNAs are involved in crucial biological processes, including development, differentiation, apoptosis and proliferation. Two families of miRNAs, miR-200 and let-7, are frequently dysregulated in ovarian cancer and have been associated with poor prognosis. Both have been implicated in the regulation of epithelial-to-mesenchymal transition, a cellular transition associated with tumor aggressiveness, tumor invasion and chemo-resistance. Moreover, miRNAs also have possible implications for improving cancer diagnosis; for example miR-200 family, let-7 family, miR-21 and miR-214 may be useful in diagnostic tests to help detect ovarian cancer at an early stage. Additionally, the use of multiple target O-modified antagomirs (MTG-AMO) to inhibit oncogenic miRNAs and miRNA replacement therapy for tumor suppressor miRNAs are essential tools for miRNA based cancer therapeutics. In this review we describe the current status of the role miRNAs play in ovarian cancer and focus on the possibilities of microRNA-based therapies and the use of microRNAs as diagnostic tools.     

Isolation,Replication and Polyhedrin Gene Sequence of an Israeli Helicoverpa Armigera Single Nucleopolyhedrovirus

A local strain of Helicoverpa armigera baculovirus was isolated from infected H. armigera larvae. Infectivity to Helicoverpa cells, restriction enzyme analysis and electron microscopy allowed its identification as a single embedded nucleopolyhedrovirus, designated HaSNPV-IS. Analysis of DNA replication, protein synthesis and polyhedrin expression in HaSNPV-infected cells located the late and very late phases of the viral cycle at 24 and 48 h after infection, respectively. The viral polyhedrin gene was isolated and characterized. It encoded for a polypeptide of 246 amino acid residues. A 32 kDa polypeptide was identified by immunoblot analysis using anti-polyhedrin antiserum. The HaSNPV-IS polyhedrin DNA sequence revealed 99.4% of homology to the HzSNPV polyhedrin. The availability of this efficient replication system and the above knowledge paves the way to future genetic engineering of the HaSNPV. This revised version was published online in July 2006 with corrections to the Cover Date.     

Poor correlation between hemolysis and jaundice in glucose 6-phosphate dehydrogenase-deficient babies

BACKGROUND: The role of hemolysis in the pathophysiology of neonatal jaundice (NNJ) in patients with glucose 6-phosphate dehydrogenase (G6PD) deficiency has been questioned recently. The aim of the present study was to determine the contribution of hemolysis to the pathophysiology of jaundice in Malay neonates with G6PD deficiency and NNJ. METHODS: Four groups of babies were included in the study: (i) G6PD deficient with NNJ; (ii) G6PD deficient without NNJ; (iii) G6PD normal with NNJ; and (iv) normal controls. Babies with other known causes of jaundice were excluded from the study. All subjects underwent the following investigations on day 3-5 after birth: hemoglobin level (Hb), serum bilirubin level, carboxyhemoglobin (CO-Hb) concentration, reticulocyte count and full blood picture. The results of the investigations were compared between the groups using SPSS version 11. RESULTS: Babies with G6PD and jaundice had a similar percentage of CO-Hb to babies with G6PD without NNJ or babies with normal G6PD and NNJ (1.76 +/- 0.40% vs 1.66 +/- 0.31% and 1.67 +/- 0.28%, respectively; P: 0.23 and 0.41, respectively). Total Hb levels and reticulocyte counts were not significantly different between the groups. The blood film showed more (even though not reaching significance) hemolysis in the G6PD patients but results of the blood film were very similar for G6PD patients with and those without NNJ. CONCLUSION: Hemolysis is not a main determinant of neonatal jaundice in G6PD-deficient babies.     

Audiologic findings after stereotactic radiosurgery in nine cases of acoustic neurinomas.

Nine cases of acoustic neurinoma were treated by stereotactic radiosurgery between 1969 and 1974. The follow-up period can now be regarded as sufficiently long for a preliminary evaluation of the results. An arrest of growth or shrinkage of the tumour was observed in 8 of the 9 cases. In one case open surgery was performed 2 years after irradiation and histological examination showed regressive changes of the type expected after irradiation. Audiological examination revealed that in the majority of cases radiosurgery could be performed without causing serious damage to the hearing function. The average hearing loss present before treatment increased on average only 20.0 dB in the most successful 7 cases. None of the patients suffered facial nerve involvement. In small and medium-sized acoustic tumours this method offers a satisfactory therapeutic alternative worthy of consideration.