Methicillin-resistant Staphylococcus aureus (MRSA) is known to cause nosocomial infections and is now becoming an emerging problem in veterinary medicine. The objective of the study was to determine the presence of MRSA in 100 cats and dogs sampled between November 2007 and April 2008 at the University Veterinary Hospital, Universiti Putra Malaysia. MRSA was detected in 8% of pets sampled. Ten percent (5/50) and 6% (3/50) of the isolates were from dogs and cats, respectively. All MRSA isolates possessed the mecA gene and were found to be resistant to at least three antimicrobials with a minimum of Oxacillin MIC of 8 μg/mL. One isolate (CT04) had an extremely high MIC of >256 μg/mL. The MLST type ST59 found in this study have been reported earlier from Singapore and other countries as a strain from animal and community-associated MRSA respectively. Pulsed-field gel electrophoresis revealed five pulsotypes. Two isolates from cats (CT27 and CT33) and three isolates from dogs (DG16, DG20, and DG49) were respectively assigned to pulsotypes B and D. The study suggests that cats and dogs in Malaysia are potential reservoirs for MRSA.
The prevalence and antibiotic susceptibility of intestinal carriage of Gram-negative bacteria among preterm infants admitted to the neonatal intensive care unit (NICU) in a tertiary teaching hospital in Malaysia were determined. A total of 34 stool specimens were obtained from preterm infants upon admission and once weekly up to two weeks during hospitalization. The presumptive colonies of Escherichia coli and Klebsiella pneumoniae were selected for identification, antibiotic susceptibility testing, and subtyping by using pulsed-field gel electrophoresis (PFGE). Out of 76 Gram-negative isolates, highest resistance was detected for amoxicillin/clavulanate (30.8%, n = 16), ceftriaxone (42.3%, n = 22), ceftazidime (28.8%, n = 15), cefoxitin (28.8%, n = 15), aztreonam (36.5%, n = 19), and polymyxin B (23.1%, n = 12). Three colistin resistant K. pneumoniae have also been detected based on E-test analysis. Thirty-nine isolates of K. pneumoniae and 20 isolates of E. coli were resistant to more than three antimicrobial classes and were categorized as multidrug resistant (MDR). PFGE analysis revealed a higher diversity in pulsotypes for K. pneumoniae (18 pulsotypes) in comparison to E. coli (four pulsotypes). In addition, a total of fifteen pulsotypes was observed from 39 MDR K. pneumoniae. The risk factors for antibiotic resistance were assessed using random forest analysis. Gender was found to be the most important predictor for colistin resistant while length, OFC, and delivery mode were showing greater predictive power in the polymyxin B resistance. This study revealed worrying prevalence rates of intestinal carriage of multidrug-resistant K. pneumoniae and E. coli of hospitalized preterm infants in Malaysia, particularly high resistance to polymyxins.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for significant numbers of nosocomial and community-acquired infections worldwide. Molecular diagnosis for MRSA nasal carriers is increasingly important for rapid detection and screening of MRSA colonization because the conventional methods are time consuming and labor intensive. However, conventional polymerase chain reaction (PCR) tests still require cold-chain storage as well as trained personnel, which makes them unsuitable for rapid high-throughput analysis. The aim of this study was to develop a thermostabilized PCR assay for MRSA in a ready-to-use form that requires no cold chain.
There is limited information about pneumococcal carriage among healthy children in Malaysia. Therefore, this study was conducted to determine the prevalence rate, serotype distribution, susceptibility pattern, and pneumococcal surface protein A (PspA) family types of Streptococcus pneumoniae isolates in the nasal carriage of children 5 years old or younger in three day care centers in Kuala Lumpur, Malaysia.
This report describes the proliferation and transmission patterns of Pasteurella multocida B:2 among stressful goats, created through dexamethasone injections. Thirty seven clinically healthy adult goats were divided into three groups consisted of 15 goats in group A, 11 goats in group B and the remaining 11 in group C. At the start of the study, all goats of group A were exposed intranasally to 1.97 x 10(10) CFU/ml of live P multocida B:2. Dexamethasone was immediately administered intramuscularly for 3 consecutive days at a dosage rate of 1 mg/kg. The exposed goats were observed for signs of HS for a period of 1 month. At the end of the 1-month period, 11 goats from group B were introduced into and commingled with the surviving goats of group A before all goats from both groups were immediately injected intramuscularly with dexamethasone for 3 consecutive days. The treatment with dexamethasone was then carried out at monthly interval throughout the 3-month study period. Goats of group C were kept separately as negative control. Three surviving goats from each group were killed at 2-week interval for a complete post-mortem examination. Two (13%) goats of group A were killed within 24 hours after intranasal exposure to P multocida B:2 while another two (13%) goats from the same group were killed on day 40, approximately 10 days after the second dexamethasone injection. All four goats showed signs and lesions typical of haemorrhagic septicaemia. Bacteraemia was detected in 3 goats of group A that were having rectal temperature higher than 41degrees C. The P. multocida B:2 isolation pattern was closely associated with dexamethasone injections when significantly (p < 0.05) higher rate of isolations from both groups were observed after each dexamethasone injection. Transmission of P multocida B:2 from goats of group A to group B was successful when P multocida B:2 was isolated from goats of group B for a period of 28 days. There was a strong correlation between dexamethasone injections, rate of bacterial isolation and serum cortisol level. The IgG level showed an increasing trend 2 weeks after exposure to P multocida B:2 and remained high throughout the study period.
Data on the carriage rate and antibiotic sensitivity pattern of Staphylococcus aureus strains prevalent in the community are not available for many developing countries including Malaysia. To estimate the extent of community S. aureus transmission, in particular methicillin-resistant S. aureus (MRSA), the prevalence of S. aureus nasal colonization in a population of healthy adults was determined. Factors associated with S. aureus nasal carriage and antibiotic sensitivity patterns of the isolates were also analyzed.
The aim of the present study was to assess and compare the antimicrobial susceptibility pattern against a panel of antibiotics and molecular and methicillin resistance-associated genotypes of 120 carriage S. aureus isolates previously isolated from a student population at two isolation events within a one-month interval. The antibiotic susceptibility of isolates was determined using the Kirby-Bauer disc-diffusion method (cefoxitin by Etest). The MRSA was screened using polymerase chain reaction for the presence of the mecA gene. The mecA-positive isolates were subjected to staphylococcal cassette chromosome (SCC) mec typing, multilocus sequence typing (MLST) and eBURST analysis. All isolates were characterized for the presence of the Panton-Valentine leukocidin (PVL) gene, an enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) pattern and the spa type. For the two occasions where S. aureus was isolated, the highest frequency of resistance was observed for penicillin (70% and 65%, respectively), with a lower rate against erythromycin and tetracycline (<12%). All isolates were susceptible to ciprofloxacin and gentamycin. As for methicillin resistance, eight isolates had minimum inhibitory concentrations (MIC) of resistant categories, but 10 isolates (8.33%) were positive for the mecA gene. The mecA-positive isolates belonged to SCCmec types I (n=9) and V (n=1). MLST was resolved for only three MRSAs, ST508 (n=1), ST88 (n=1) and ST96 (n=1). The results of the eBURST analysis showed that the MRSA isolates analyzed in the present study were potentially related to MRSA identified in other countries. Approximately half of the persistent S. aureus carriers harbored S. aureus of a similar spa type in the respective individuals during both isolation events. A persistent antimicrobial pattern and limited distinct MRSAs were observed over the short study period. The latter frequently exhibited SCCmec type I, commonly associated with hospital-acquired (HA) characteristics, but further delineation is needed to justify the origins of these bacteria.
Capsular serotypes K1 and K2 of Klebsiella pneumoniae are thought to the major virulence determinants responsible for liver abscess. The intestine is one of the major reservoirs of K. pneumoniae, and epidemiological studies have suggested that the majority of K. pneumoniae infections are preceded by colonization of the gastrointestinal tract. The possibility of fecal-oral transmission in liver abscess has been raised on the basis of molecular typing of isolates. Data on the serotype distribution of K. pneumoniae in stool samples from healthy individuals has not been previously reported. This study investigated the seroepidemiology of K. pneumoniae isolates from the intestinal tract of healthy Chinese in Asian countries. Stool specimens from healthy adult Chinese residents of Taiwan, Japan, Hong Kong, China, Thailand, Malaysia, Singapore, and Vietnam were collected from August 2004 to August 2010 for analysis.
In addition to being a human pathogen, Staphylococcus aureus causes an array of infections in economically important livestock animals, particularly pigs. In Asia, there have been few reports on livestock-associated meticillin-resistant S. aureus (LA-MRSA), mostly from developed countries, with very few data available from resource-limited countries, not because of low prevalence but probably due to a shortage of diagnostic facilities. Unlike the wide spread of sequence type 398 (ST398) LA-MRSA in European countries and North America, ST9 predominates in most Asian countries. The prevalence of LA-MRSA among pigs in Asian countries varied widely (0.9-42.5%). The prevalence may vary by geographic location, age of pigs and sampling methodologies. Among pig farmers, the prevalence of nasal MRSA colonisation varied from 5.5% in Malaysia to 15% in China and 19.2% in Taiwan. Although most LA-MRSA isolates in Asia are of the same ST, molecular characteristics are not all the same. Dominant isolates in China were characterised as spa type t899-SCCmec III and t899-SCCmec IVb or V for isolates in Hong Kong, and t899-untypeable SCCmec for Taiwan. Dominant isolates in Malaysia were spa type t4358-SCCmec V and t337-SCCmec IX for isolates in Thailand. In addition, MRSA ST221 was reported in Japan and MRSA ST398 was isolated from commercial pigs in South Korea. Attention should be paid because pigs could become an important reservoir for MRSA and spread them to humans, as observed in many countries. There is a potential risk from the livestock reservoir to community and hospitals.
Urinary tract infections (UTIs) are among the most common infectious diseases of humans, with Escherichia coli responsible for >80% of all cases. One extreme of UTI is asymptomatic bacteriuria (ABU), which occurs as an asymptomatic carrier state that resembles commensalism. To understand the evolution and molecular mechanisms that underpin ABU, the genome of the ABU E. coli strain VR50 was sequenced. Analysis of the complete genome indicated that it most resembles E. coli K-12, with the addition of a 94-kb genomic island (GI-VR50-pheV), eight prophages, and multiple plasmids. GI-VR50-pheV has a mosaic structure and contains genes encoding a number of UTI-associated virulence factors, namely, Afa (afimbrial adhesin), two autotransporter proteins (Ag43 and Sat), and aerobactin. We demonstrated that the presence of this island in VR50 confers its ability to colonize the murine bladder, as a VR50 mutant with GI-VR50-pheV deleted was attenuated in a mouse model of UTI in vivo. We established that Afa is the island-encoded factor responsible for this phenotype using two independent deletion (Afa operon and AfaE adhesin) mutants. E. coli VR50afa and VR50afaE displayed significantly decreased ability to adhere to human bladder epithelial cells. In the mouse model of UTI, VR50afa and VR50afaE displayed reduced bladder colonization compared to wild-type VR50, similar to the colonization level of the GI-VR50-pheV mutant. Our study suggests that E. coli VR50 is a commensal-like strain that has acquired fitness factors that facilitate colonization of the human bladder.
Little is known about Clostridium difficile infection (CDI) in Asia. The aims of our study were to explore (i) the prevalence, risk factors and molecular epidemiology of CDI and colonization in a tertiary academic hospital in North-Eastern Peninsular Malaysia; (ii) the rate of carriage of C. difficile among the elderly in the region; (iii) the awareness level of this infection among the hospital staffs and students. For stool samples collected from hospital inpatients with diarrhea (n = 76) and healthy community members (n = 138), C. difficile antigen and toxins were tested by enzyme immunoassay. Stool samples were subsequently analyzed by culture and molecular detection of toxin genes, and PCR ribotyping of isolates. To examine awareness among hospital staff and students, participants were asked to complete a self-administered questionnaire. For the hospital and community studies, the prevalence of non-toxigenic C. difficile colonization was 16% and 2%, respectively. The prevalence of CDI among hospital inpatients with diarrhea was 13%. Out of 22 C. difficile strains from hospital inpatients, the toxigenic ribotypes 043 and 017 were most common (both 14%). In univariate analysis, C. difficile colonization in hospital inpatients was significantly associated with greater duration of hospitalization and use of penicillin (both P < 0·05). Absence of these factors was a possible reason for low colonization in the community. Only 3% of 154 respondents answered all questions correctly in the awareness survey. C. difficile colonization is prevalent in a Malaysian hospital setting but not in the elderly community with little or no contact with hospitals. Awareness of CDI is alarmingly poor.
Methicillin-resistant Staphylococcus aureus (MRSA) of sequence type 398 (ST398) has frequently been detected in pigs and pig handlers. However, in Malaysia, sampling 360 pigs and 90 pig handlers from 30 farms identified novel ST9-spa type t4358-staphylococcal cassette chromosome mec type V MRSA strains that were found to transiently colonize more than 1% of pigs and 5.5% of pig handlers.
Species of fungi belonging to the order Mucorales can be found everywhere in the environment. Gilbertella persicaria, which belongs to this order, have often been isolated from fruits and in water systems. However, there has been no report of isolation of this fungus from human samples. During a gut mycobiome study, from the Segamat community, Gilbertella persicaria was isolated from a human fecal sample and was characterized through a series of morphological assessment, biochemical tests, and molecular techniques. The isolate produced a white velvety surface that turned grayish after 24 h. Although no biofilm production was observed, the results indicated that the isolate could form calcium oxalate crystals, produced urease, and was resistant to low pH. The isolate was sensitive to amphotericin but resistant to voriconazole and itraconazole. The features of this fungus that could help in its survival in the human gut are also discussed.
BACKGROUND: Gastrointestinal carriage of multidrug resistant (MDR) Gram-negative bacilli, especially Klebsiella pneumoniae and Escherichia coli, was highly associated with severe nosocomial infections. The main objectives of this study were to determine the clonal relatedness of intestinal carriage and transmission risk factors of MDR E. coli and K. pneumoniae amongst preterm infants admitted to the neonatal intensive care unit (NICU).
METHODS: A prospective cohort study of preterm infants with gestational age
The humoral immune response against 43 staphylococcal antigens was compared among hospitalized patients where none of them had any staphylococcal infection on the day of admission with or without nasal Staphylococcus aureus carriage. Fifty-nine carriers and 59 matched non-carriers were studied. The carriers harbored S. aureus of 35 different spa types, including three t037/ST239 methicillin-resistant S. aureus (MRSA) (5.1%). Among the 118 patients, 31 acquired S. aureus during hospitalization. In colonized and non-colonized patients, unique patterns of S. aureus-specific immune responses were observed. The mean fluorescence indices (MFIs) of antibodies against 36/43 (83.7%) antigens were seen to be elevated among carriers. The MFI among carriers with acquisition was significantly higher for staphylococcal superantigen-like protein 5 (SSL5, p = 0.028) when compared to carriers without acquisition. High antibody levels against staphylococcal enterotoxin A (SEA) among carriers illustrate its role as a superantigen in both infection and colonization. We also report a dynamic immune response in S. aureus-carrying patients against the recently reported formyl peptide receptor-like inhibitory (FLIPr)-like protein. In the current study, the dynamics of antibodies against staphylococcal antigens among carrier patients seem quite similar to non-carrier patients. To better understand the dynamic immunogenicity during S. aureus infection and colonization, artificial colonization studies and investigation of the changes in the levels of antibodies against other staphylococcal antigens are recommended.
Salmonella enterica serovar Typhi is a human pathogen that causes typhoid fever predominantly in developing countries. In this article, we describe the whole genome sequence of the S. Typhi strain CR0044 isolated from a typhoid fever carrier in Kelantan, Malaysia. These data will further enhance the understanding of its host persistence and adaptive mechanism.
In Malaysia, various aspects of the epidemiology of pneumococcal carriage and disease remain largely unclear due to the lack of supporting data. Although a number of relevant studies have been documented, their individual discrete findings are not sufficient to inform experts on pneumococcal epidemiology at a national level. Therefore, in this review we aim to bring together and systematically evaluate the key information regarding pneumococcal disease epidemiology in Malaysia and provide a comprehensive overview of the data. Major aspects discussed include pneumococcal carriage, disease incidence and prevalence, age factors, invasiveness of pneumococci, serotypes, molecular epidemiology and antibiotic susceptibility. Penicillin resistance is increasingly prevalent and studies suggest that the majority of pneumococcal serotypes causing pneumococcal disease in Malaysia are covered by currently available conjugate vaccines. Continued surveillance is needed to provide a better understanding of pneumococcal epidemiology in Malaysia.
Salmonella enterica serovar Typhi (S. Typhi) is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC) biofilm inoculator (96-well peg lid) and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates) and D-threonine (amino acid) were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among different S. Typhi strains has suggested the possible involvement of various metabolic pathways that might be related to the virulence and pathogenesis of this host-restricted human pathogen. The data serve as a caveat for future in-vivo studies to investigate the carbon metabolic activity to the pathogenesis of S. Typhi.
BACKGROUND: Research has shown that athletes are carriers of Staphylococcus aureus during physical activity.
OBJECTIVE: To estimate the mean total plate count of S aureus carried by footballers before and after training at an indoor venue.
METHODS: Forty Malay and 20 Indian students volunteered to participate. There was also a control group consisting of 40 Malay and 20 Indian students who were not active. The experimental group were active footballers who had played at school or club level. The subjects were healthy and free of skin infection. The experiment was divided into three sessions, with 20 subjects present at each. At each session, the subjects trained for one hour. Swabs were taken from the skin, nose, and ear before and after training. For the control group, swabs were taken only once from the skin, nose, and ear. The swabs were subjected to biochemical tests and then streaked and cultured aerobically in Baird Parker agar plates for 24 hours at 37 degrees C. Black colonies with a clear zone were presumed to be S aureus, and the mean total plate count of the colonies was estimated. Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, o-nitrophenyl beta-D-galactopyranoside (ONPG), and mannitol fermentation tests were used to confirm the colonies as S aureus. A haemolysin test was conducted with human blood to confirm haemolytic activity.
RESULTS: All subjects in the experimental group were carrying S aureus both before and after training. The estimated mean total counts of colonies from the skin, ear, and nose for the Malays before training were 33, 71, and 312 respectively. Counts after training were 21, 44, and 452 respectively. The results for the Indians were 72, 80, and 309 respectively before training and 55, 200, and 466 respectively after training. The positive results for Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, ONPG, and mannitol fermentation tests were 100%, 96%, 95%, 95%, 93%, 93%, and 90% respectively. All subjects in the control group were also carrying S aureus.
CONCLUSIONS: All of the players were carriers of S aureus during training. The decrease in total count from the skin for both races may be due to lysozyme activity lysing the bacterial cells. Contamination of the environment with these bacteria may have increased the estimated total plate count in the nose. The experimental group face a higher risk of infection because of lower immunity during training and higher rate of injuries compared with the control group.