RNA-seq transcriptome and pathway analysis of the medicinal mushroom Lignosus tigris (Polyporaceae) offer insights into its bioactive compounds with anticancer and antioxidant potential.

ETHNOPHARMACOLOGICAL RELEVANCE: Medicinal mushrooms belonging to the Lignosus spp., colloquially known as Tiger Milk mushrooms (TMMs), are used as traditional medicine by communities across various regions of China and Southeast Asia to enhance immunity and to treat various diseases. At present, three Lignosus species have been identified in Malaysia: L. rhinocerus, L. tigris, and L. cameronensis. Similarities in their macroscopic morphologies and the nearly indistinguishable appearance of their sclerotia often lead to interchangeability between them. Hence, substantiation of their traditional applications via identification of their individual bioactive properties is imperative in ensuring that they are safe for consumption. L. tigris was first identified in 2013. Thus far, studies on L. tigris cultivar sclerotia (Ligno TG-K) have shown that it possesses significant antioxidant activities and has greater antiproliferative action against selected cancer cells in vitro compared to its sister species, L. rhinocerus TM02®. Our previous genomics study also revealed significant genetic dissimilarities between them. Further omics investigations on Ligno TG-K hold immense potential in facilitating the identification of its bioactive compounds and their associated bioactivities. AIM OF STUDY: The overall aim of this study was to investigate the gene expression profile of Ligno TG-K via de novo RNA-seq and pathway analysis. We also aimed to identify highly expressed genes encoding compounds that contribute to its cytotoxic and antioxidant properties, as well as perform a comparative transcriptomics analysis between Ligno TG-K and its sister species, L. rhinocerus TM02®. MATERIALS AND METHODS: Total RNA from fresh 3-month-old cultivated L. tigris sclerotia (Ligno TG-K) was extracted and analyzed via de novo RNA sequencing. Expressed genes were analyzed using InterPro and NCBI-Nr databases for domain identification and homology search. Functional categorization based on gene functions and pathways was performed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Clusters of Orthologous Genes (COG) databases. Selected genes were subsequently subjected to phylogenetic analysis. RESULTS: Our transcriptomics analysis of Ligno TG-K revealed that 68.06% of its genes are expressed in the sclerotium; 80.38% of these were coding transcripts. Our analysis identified highly expressed transcripts encoding proteins with prospective medicinal properties. These included serine proteases (FPKM = 7356.68), deoxyribonucleases (FPKM = 3777.98), lectins (FPKM = 3690.87), and fungal immunomodulatory proteins (FPKM = 2337.84), all of which have known associations with anticancer activities. Transcripts linked to proteins with antioxidant activities, such as superoxide dismutase (FPKM = 1161.69) and catalase (FPKM = 1905.83), were also highly expressed. Results of our sequence alignments revealed that these genes and their orthologs can be found in other mushrooms. They exhibit significant sequence similarities, suggesting possible parallels in their anticancer and antioxidant bioactivities. CONCLUSION: This study is the first to provide a reference transcriptome profile of genes expressed in the sclerotia of L. tigris. The current study also presents distinct COG profiles of highly expressed genes in Ligno TG-K and L. rhinocerus TM02®, highlighting that any distinctions uncovered may be attributed to their interspecies variations and inherent characteristics that are unique to each species. Our findings suggest that Ligno TG-K contains bioactive compounds with prospective medicinal properties that warrant further investigations. CLASSIFICATION: Systems biology and omics.

The Wound Healing Potential of Lignosus rhinocerus and Other Ethno-myco Wound Healing Agents.

Wound care has become increasingly important over the years. Various synthetic products for wound care treatment have been reported to cause toxic side effects and therefore natural products are in significant demand as they have minimal side effects. The presence of bioactive compounds in medicinal mushrooms contributes to various biological activities which assist in the early inflammatory phase, keratinocyte proliferation, and its migration enhancement which are pertinent to wound rehabilitation. Lignosus rhinocerus (tiger milk mushroom) can reduce the inflammation phase in wound healing by fighting off bacterial infection and modulating pro-inflammatory cytokines expression in the early stage to avoid prolonged inflammation and tissue damage. The antibacterial, immunomodulating, and anti-inflammatory activities exhibited by most macrofungi play a key role in enhancing wound healing. Several antibacterial and antifungal compounds sourced from traditional botanicals/products may prevent further complications and reoccurrence of injury to a wounded site. Scientific studies are actively underway to ascertain the potential use of macrofungi as a wound healing agent.

In vivo anti-tumor activity of Lignosus rhinocerus TM02® using a MCF7-xenograft NCr nude mice model.

ETHNOPHARMACOLOGICAL RELEVANCE: Lignosus rhinocerus (Cooke) Ryvarden (also known as Tiger Milk mushroom, TMM), is a basidiomycete belonging to the Polyporaceae family. It has been documented to be used by traditional Chinese physicians and indigenous people in Southeast Asia to treat a variety of illnesses, such as gastritis, arthritis, and respiratory conditions, as well as to restore patients' physical well-being. TMM has also been used in folk medicine to treat cancer. For example, people from the indigenous Kensiu tribe of northeast Kedah (Malaysia) apply shredded TMM sclerotium mixed with water directly onto breast skin to treat breast cancer, while Chinese practitioners from Hong Kong, China prescribe TMM sclerotium as a treatment for liver cancer. L. rhinocerus has previously been demonstrated to possess selective anti-proliferative properties in vitro, however pre-clinical in vivo research has not yet been conducted. AIM OF STUDY: This study aimed to examine the anti-tumor activities of L. rhinocerus TM02®, using two different sample preparations [cold water extract (CWE) and fraction] via various routes of administration (oral and intraperitoneal) on an MCF7-xenograft nude mouse model. This study also investigated the inhibitory effect of TM02® CWE and its fractions against COX-2 in vitro using LPS-induced RAW264.7 macrophages, on the basis of the relationship between COX-2 and metastasis, apoptosis resistance, as well as the proliferation of cancer cells. MATERIALS AND METHODS: The first preparation, L. rhinocerus TM02® sclerotium powder (TSP) was dissolved in cold water to obtain the cold water extract (CWE). It was further fractionated based on its molecular weight to obtain the high (HMW), medium (MMW) and low (LMW) molecular weight fractions. The second preparation, known as the TM02® rhinoprolycan fraction (TRF), was obtained by combining the HMW and MMW fractions. TSP was given orally to mimic the daily consumption of a supplement; TRF was administered intraperitoneally to mimic typical tumorous cancer treatment with a rapid and more thorough absorption through the peritoneal cavity. Another experiment was conducted to examine changes in COX-2 activity in LPS-induced RAW264.7 macrophages after a 1-h pre-treatment with CWE, HMW, and MMW. RESULTS: Our results revealed that intraperitoneal TRF-injection (90 µg/g BW) for 20 days reduced initial tumor volume by ∼64.3% (n = 5). The percentage of apoptotic cells was marginally higher in TRF-treated mice vs. control, suggesting that induction of apoptosis as one of the factors that led to tumor shrinkage. TSP (500 µg/g BW) oral treatment (n = 5) for 63 days (inclusive of pre-treatment prior to tumor inoculation) effectively inhibited tumor growth. Four of the five tumors totally regressed, demonstrating the effectiveness of TSP ingestion in suppressing tumor growth. Although no significant changes were found in mouse serum cytokines (TNF-α, IL-5, IL-6 and CCL2), some increasing and decreasing trends were observed. This may suggest the immunomodulatory potential of these treatments that can directly or indirectly affect tumor growth. Pre-treatment with CWE, HMW and MMW significantly reduced COX-2 activity in RAW264.7 macrophages upon 24 h LPS-stimulation, suggesting the potential of L. rhinocerus TM02® extract and fractions in regulating M1/M2 polarization. CONCLUSION: Based on the findings of our investigation, both the rhinoprolycan fraction and crude sclerotial powder from L. rhinocerus TM02® demonstrated tumor suppressive effects, indicating that they contain substances with strong anticancer potential. The antitumor effects of L. rhinocerus TM02® in our study highlights the potential for further explorations into its mechanism of action and future development as a prophylactic or adjunct therapeutic against tumorous cancer.

Chinese Caterpillar Mushroom, Ophiocordyceps sinensis (Ascomycota), Cold-Water Extract Relaxes the Rat Isolated Bladder.

Ophiocordyceps sinensis is a popular medicinal mushroom used for various health conditions, including alleviation of frequent urination, which is a major symptom of overactive bladder (OAB) syndrome. This study aimed to investigate the effect of O. sinensis (OCS02 cultivar) cold-water extract (CWE) against bladder contractility using the organ bath technique. The bladder was removed from male Sprague-Dawley rats and cut into longitudinal strips of 2 mm × 8 mm. In some experiments, the urothelium was removed to study its role in CWE-induced responses. CWE elicited a biphasic response consisting of an immediate, transient contraction that was followed by a sustained relaxation in bladder strips precontracted with carbachol, a muscarinic agonist. Removal of urothelium did not alter the magnitude of the contractile response but significantly attenuated the relaxation response. In the presence of L-NAME (nitric oxide synthase inhibitor) and sodium nitroprusside (nitric oxide donor), CWE-induced transient contraction was enhanced, whereas the relaxation response was significantly reduced. Following preincubation with CWE, the amplitude and the frequency of the spontaneous myogenic contractions induced by carbachol, as well as the contractile response toward calcium, were significantly suppressed. Findings from this study show that the urothelium plays a role in the relaxant effect of CWE. Its mechanisms of action include the regulation of nitric oxide and inhibition of calcium influx.

Immunomodulatory Effect and an Intervention of TNF Signalling Leading to Apoptotic and Cell Cycle Arrest on ORL-204 Oral Cancer Cells by Tiger Milk Mushroom, Lignosus rhinocerus.

Research background: Tiger milk mushroom (Lignosus rhinocerus) is a medicinal mushroom that is geographically distributed in the region of South China, Thailand, Malaysia, Indonesia, Philippines and Papua New Guinea. Consumption of its sclerotium has been reported to treat various ailments. However, its anticancer potential towards oral cancer cell lines is yet to be determined considering the traditional method of its consumption by biting/chewing of the sclerotium. Experimental approach: Mushroom sclerotial powder of cultivar TM02® was extracted and fractionated in a chromatographic column prior to cytotoxicity testing against a panel of human oral cancer cell lines. The capability of the identified bioactive fraction in regulating several molecules associated with its tumour necrosis factor (TNF) pathway was investigated. Results and conclusions: 2,5-Diphenyl-2H-tetrazolium bromide (MTT) proliferation assay indicated that cell lines ORL-48 (derived from gingiva), ORL-188 (derived from the tongue) and ORL-204 (derived from buccal mucosa) were inhibited by cold water extract of L. rhinocerus sclerotia and its high-molecular-mass fraction (HMM) in varying degrees with ORL-204 being most affected. Hence, the treatment of ORL-204 with HMM mushroom extract was further investigated. HMM mushroom extract induced apoptosis and G0/G1 phase cell cycle arrest through caspase-3/7 cleavage. Activities of MIP2 and COX-2 were downregulated by 0.2- and 4.6-fold respectively in the HMM mushroom extract-treated ORL-204 cells. Novelty and scientific contribution: Using ORL-204, we showed that HMM mushroom extract may act via the TNF pathway at various network sites as a potential dietary compound for cancer prevention and natural adjunct therapeutic to conventional cancer treatment.

Longitudinal Assessment of the Tiger Milk Medicinal Mushroom, Lignosus rhinocerus (Agaricomycetes), Sclerotium Cultivar: Uniformity of Bioactive Components.

Traditional use of the tiger milk medicinal mushroom, Lignosus rhinocerus, to treat various illnesses has been recorded for > 4 centuries. Successful cultivation of L. rhinocerus using proprietary solid-state fermentation (SSF) technology by LiGNO Biotech has enabled large-scale production of L. rhinocerus sclerotia (termed L. rhinocerus TM02) and further investigations into its medicinal properties. Pharmacological activities of L. rhinocerus TM02, including its antioxidant, anti-inflammatory, anticancer, and immunomodulatory effects and the bioactive components responsible, have been validated by various scientific studies. In this study, we assessed the consistency of the bioactive components in 11 batches of L. rhinocerus TM02 produced over a 9-year period. The different batches of L. rhinocerus TM02 consisted of stable protein, polysaccharide, and glycoprotein contents, and all tested samples were comparable to the wild type. L. rhinocerus TM02 had greater protein, carbohydrate, and glycoprotein contents, which were mostly bioactive compared to another cultivar from a different cultivation technology (TM-UN). Together with previous scientific validations, L. rhinocerus TM02 produced using SSF cultivation is of optimal quality with high consistent bioactive contents, which can be an appropriate indicator for quality validation of the much sought-after medicinal mushroom, L. rhinocerus.

Antioxidant and Cytotoxic Effects and Identification of Ophiocordyceps sinensis Bioactive Proteins Using Shotgun Proteomic Analysis.

RESEARCH BACKGROUND: Ophiocordyceps sinensis, a highly valued medicinal fungus, is close to extinction due to overexploitation. Successful cultivation of O. sinensis fruiting body (OCS02®) shows that the cultivar has a promising nutritional value and numerous bioactive compounds. Antioxidant and antiproliferative properties and biologically active proteins of the OCS02® are investigated for possible development into nutraceuticals. EXPERIMENTAL APPROACH: The chemical composition of the OCS02® cold water extract was determined, and the antioxidant activities were examined using ferric reducing, DPPH• and O2 •- scavenging assays. Tetrazolium dye (MTT) cytotoxic assay was performed to assess the antiproliferative activity of the extract. Bioactive proteins in the active fraction of the extract were identified using liquid chromatography (LC) and tandem-mass spectrometry (MS/MS). RESULTS AND CONCLUSIONS: The OCS02® extract exhibited strong O2 •- scavenging (expressed as Trolox equivalents (18.4±1.1) mol/g) and potent cytotoxic activities against adenocarcinomic human alveolar basal epithelial (A549) cells (IC50=(58.2±6.8) µg/mL). High molecular mass polysaccharides, proteins and protein-polysaccharide complexes could have contributed to the antioxidant and cytotoxic selectivity of the OCS02®. LC-MS/MS analysis identified several potential cytotoxic proteases and an oxalate decarboxylase protein which may exhibit protection effects on kidneys. NOVELTY AND SCIENTIFIC CONTRIBUTIONS: The findings demonstrate the potential of OCS02® to be developed into functional food due to its promising superoxide anion radical scavenging capacity, cytotoxic effect and presence of biopharmaceutically active proteins.

Proteins from Lignosus tigris with selective apoptotic cytotoxicity towards MCF7 cell line and suppresses MCF7-xenograft tumor growth.

BACKGROUND: Lignosus tigris, a recently discovered species of the unique Lignosus family, has been traditionally used by the indigenous communities in Peninsular Malaysia to treat various ailments and as an alternative medicine for cancer treatment. The L. tigris cultivar sclerotia (Ligno TG-K) was found to contain numerous bioactive compounds with beneficial biomedicinal properties and the sclerotial extract exhibited potent antioxidant activity. However, the anticancer property of the Ligno TG-K including in vitro and in vivo antitumor effects as well as its anticancer active compounds and the mechanisms has yet to be investigated. METHODS: The cytotoxicity of the Ligno TG-K against human breast (MCF7), prostate (PC3) and lung (A549) adenocarcinoma cell lines was evaluated using MTT cytotoxicity assay. The cytotoxic mechanisms of the active high molecular weight proteins (HMWp) fraction were investigated through detection of caspases activity and apoptotic-related proteins expression by Western blotting. The in vivo antitumor activity of the isolated HMWp was examined using MCF7 mouse xenograft model. Shotgun LC-MS/MS analysis was performed to identify the proteins in the HMWp. RESULTS AND DISCUSSION: Cold water extract of the sclerotia inhibited proliferation of MCF7, A549 and PC3 cells with IC50 ranged from 28.9 to 95.0 µg/mL. Bioassay guided fractionation of the extract revealed that HMWp exhibited selective cytotoxicity against MCF7 cells via induction of cellular apoptosis by the activation of extrinsic and intrinsic signaling pathways. HMWp activated expression of caspase-8 and -9 enzymes, and pro-apoptotic Bax protein whilst inhibiting expression of tumor survivor protein, Bcl-2. HMWp induced tumor-cell apoptosis and suppressed growth of tumor in MCF-7 xenograft mice. Lectins, serine proteases, RNase Gf29 and a 230NA deoxyribonuclease are the major cytotoxic proteins that accounted for 55.93% of the HMWp. CONCLUSION: The findings from this study provided scientific evidences to support the traditional use of the L. tigris sclerotia for treatment of breast cancer. Several cytotoxic proteins with high abundance have been identified in the HMWp of the sclerotial extract and these proteins have potential to be developed into new anticancer agents or as adjunct cancer therapy.

Heterologous expression of cytotoxic sesquiterpenoids from the medicinal mushroom Lignosus rhinocerotis in yeast.

BACKGROUND: Genome mining facilitated by heterologous systems is an emerging approach to access the chemical diversity encoded in basidiomycete genomes. In this study, three sesquiterpene synthase genes, GME3634, GME3638, and GME9210, which were highly expressed in the sclerotium of the medicinal mushroom Lignosus rhinocerotis, were cloned and heterologously expressed in a yeast system. RESULTS: Metabolite profile analysis of the yeast culture extracts by GC-MS showed the production of several sesquiterpene alcohols (C15H26O), including cadinols and germacrene D-4-ol as major products. Other detected sesquiterpenes include selina-6-en-4-ol, ß-elemene, ß-cubebene, and cedrene. Two purified major compounds namely (+)-torreyol and α-cadinol synthesised by GME3638 and GME3634 respectively, are stereoisomers and their chemical structures were confirmed by 1H and 13C NMR. Phylogenetic analysis revealed that GME3638 and GME3634 are a pair of orthologues, and are grouped together with terpene synthases that synthesise cadinenes and related sesquiterpenes. (+)-Torreyol and α-cadinol were tested against a panel of human cancer cell lines and the latter was found to exhibit selective potent cytotoxicity in breast adenocarcinoma cells (MCF7) with IC50 value of 3.5 ± 0.58 µg/ml while α-cadinol is less active (IC50 = 18.0 ± 3.27 µg/ml). CONCLUSIONS: This demonstrates that yeast-based genome mining, guided by transcriptomics, is a promising approach for uncovering bioactive compounds from medicinal mushrooms.

Acute Toxicity Study and the In Vitro Cytotoxicity of a Black Lingzhi Medicinal Mushroom, Amauroderma rugosum (Agaricomycetes), from Malaysia.

Amauroderma rugosum is a wild medicinal mushroom also known as budak cendawan sawan. Members of the indigenous Malaysian Temuan community wear the fresh stipes as a necklace to prevent epileptic seizure and unremitting crying by babies. In our previous studies, A. rugosum exhibited significant antioxidant and anti-inflammatory activities. The aim of this study was to determine the toxicity (in the event that a stipe is accidentally bitten) and cytotoxicity of this mushroom on Sprague-Dawley rats and selected cell lines. A. rugosum was orally administered to test chemicals according to Organisation for Economic and Co-operation and Development guidelines (TG 425, adopted October 3, 2008). Blood samples were hematologically and biochemically analyzed and multiple tissue sections from each organ were examined using light microscopy. Cytotoxicity of various A. rugosum extracts was also determined against MCF-7 and A-549 cell lines. Our results showed that oral administration of a single dose of mycelial powder (2000 mg/kg) had no adverse effect on the growth rate or hematological and clinical biochemical parameters. Histological studies showed that the treatments did not induce any pathological changes in the organs of the tested animals. All the treated rats survived beyond the 14-day observation period. Methanol and cold and hot water extracts of the freeze-dried mycelial culture of A. rugosum exhibited no or little cytotoxic effect against the MCF-7 and A-549 cell lines.

Sub-Acute Toxicity Study of Tiger Milk Mushroom Lignosus tigris Chon S. Tan Cultivar E Sclerotium in Sprague Dawley Rats.

Lignosus also known as "Tiger Milk Mushroom," is classified in the family Polyporaceae and mainly consumed for its medicinal properties in Southeast Asia and China. The sclerotium is known as the part with medicinal value and often used by the natives to treat a variety of ailments. Lignosus tigris Chon S. Tan, one of the species of the Malaysia Tiger Milk mushroom, has recently been successfully cultivated in laboratory. Earlier studies have demonstrated the L. tigris cultivar E sclerotia exhibited beneficial biomedicinal properties. This study evaluated the potential toxicity of L. tigris E sclerotia in a 28-day sub-acute oral administration in Sprague Dawley (SD) rats. L. tigris E sclerotial powder was administered orally at three different doses of 250, 500, and 1000 mg/kg to the SD rats once daily, consecutively for 28-days. Body weight of the rats was recorded and general behavior, adverse effects, and mortality were observed daily throughout the experimental period. At the end of the experiment, blood hematology and biochemistry, relative organ weights, and histopathological analysis were performed. Results showed that there were no mortality nor signs of toxicity throughout the 28-day sub-acute toxicity study. Oral administration of the L. tigris E sclerotial powder at daily dose up to 1000 mg/kg had no significant effects in body weight, relative organ weight, blood hematological and biochemistry, gross pathology, and histopathology of the organs. L. tigris E sclerotial powder did not cause any treatment-related adverse effect in the rats at different treatment dosages up to 1000 mg/kg. As the lethal dose for the rats is above 1000 mg/kg, the no-observed-adverse-effect level (NOAEL) dose is more than 1000 mg/kg.

Nutritional composition, antioxidant properties, and toxicology evaluation of the sclerotium of Tiger Milk Mushroom Lignosus tigris cultivar E.

The Tiger Milk Mushroom (Lignosus spp.) is an important medicinal mushroom in Southeast Asia and has been consumed frequently by the natives as a cure for a variety of illnesses. In this study, we hypothesized that Lignosus tigris (cultivar E) sclerotium may contain high nutritional value and antioxidant properties, is nontoxic and a potential candidate as a dietary supplement. The chemical and amino acid compositions of the sclerotium were evaluated and antioxidant activities of the sclerotial extracts were assessed using ferric reducing antioxidant power; 1,1-diphenyl-2-picrylhydrazyl; and superoxide anion radical scavenging assays. Acute toxicity of the L. tigris E sclerotium was assessed using a rat model study. The sclerotium was found to be rich in carbohydrate, protein, and dietary fibers with small amounts of fat, calories, and sugar. The amino acid composition of the protein contains all essential amino acids, with a protein score of 47. The sclerotial extracts contain phenolics, terpenoids, and glucan. The ferric reducing antioxidant power values of the various sclerotial extracts (hot water, cold water, and methanol) ranged from 0.008 to 0.015 mmol min(-1) g(-1) extract, while the 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radical scavenging activities ranged from 0.11 to 0.13, and -2.81 to 9.613 mmol Trolox equivalents g(-1) extract, respectively. Acute toxicity assessment indicated that L. tigris E sclerotial powder was not toxic at the dose of 2000 mg kg(-1). In conclusion, L. tigris E sclerotium has the potential to be developed into a functional food and nutraceutical.

Variable carbon catabolism among Salmonella enterica serovar Typhi isolates.

BACKGROUND: Salmonella enterica serovar Typhi (S. Typhi) is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever) and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. METHODOLOGY/PRINCIPAL FINDINGS: To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas of typhoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates) was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. CONCLUSION: The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen.

Prevalence and characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Escherichia coli from pediatric wards of a Malaysian hospital.

The emergence of Escherichia coli resistant to extended-spectrum cephalosporins (ESCs) is of concern as ESC is often used to treat infections by Gram-negative bacteria. One-hundred and ten E. coli strains isolated in 2009-2010 from children warded in a Malaysian tertiary hospital were analyzed for their antibiograms, carriage of extended-spectrum beta-lactamase (ESBL) and AmpC genes, possible inclusion of the beta-lactamase genes on an integron platform, and their genetic relatedness. All E. coli strains were sensitive to carbapenems. About 46% of strains were multidrug resistant (MDR; i.e., resistant to ≥3 antibiotic classes) and almost half (45%) were nonsusceptible to ESCs. Among the MDR strains, high resistance rates were observed for ampicillin (98%), tetracycline (75%), and trimethoprim/sulfamethoxazole (73%). Out of 110 strains, bla(TEM-1) (49.1%), bla(CTX-M) (11.8%), and bla(CMY-2) (6.4%) were detected. Twenty-one strains were ESBL producers. CTX-M-15 was the predominant CTX-M variant found and this is the first report of a CTX-M-27-producing E. coli strain from Malaysia. Majority (3.1%) of the strains harbored class 1 integron-encoded integrases with a predominance of aadA and dfr genes within the integron variable region. No gene cassette encoding ESBL genes was found and integrons were not significantly associated with ESBL or non-ESBL producers. Possible clonal expansion was observed for few CTX-M-15-positive strains but the O25-ST131 E. coli clone known to harbor CTX-M-15 was not detected while CMY-2-positive strains were genetically diverse.

Antimicrobial susceptibility profiling and genomic diversity of multidrug-resistant Acinetobacter baumannii isolates from a teaching hospital in Malaysia.

The resistance phenotypes and genomic diversity of 185 Acinetobacter baumannii isolates obtained from the intensive care unit (ICU) of a local teaching hospital in Kuala Lumpur from 2006 to 2009 were determined using antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Antibiogram analyses showed that the isolates were fully resistant to ß-lactam antimicrobials and had high resistance rates to the other antimicrobial agents tested. However, the isolates were susceptible to polymyxin B. Resistance to cefoperazone/sulbactam was only detected in strains isolated from 2007 to 2009. Some environmental isolates and an isolate from the hands of a healthcare worker (HCW) had identical resistance profiles and PFGE profiles that were closely related to patient isolates. Cluster analyses based on the PFGE profiles showed there was a persistent clone of endemic isolates in the ICU environment. The transmission route from HCWs to fomites to patients, which caused a long-term infection in the ICU of the University Malaya Medical Centre, was observed in this study. These data provide a better understanding of A. baumannii epidemiology within the hospital and the possible transmission routes. Knowledge of changes in the resistance rates of A. baumannii in our local hospital will improve antimicrobial therapy.