Clostridium difficile infection (CDI) causes mild to severe diarrhoea and pseudomembranous colitis in patients who had prior antibiotic exposure. Despite CDI being prevalent worldwide, its epidemiological data is scanty in Malaysia. This study aimed to determine the prevalence and incidence of CDI at Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Stool specimens from 147-suspected CDI patients were obtained from 1 November 2011 until 31 October 2012. The presence of C. difficile toxin A and/or B were detected using a commercial immunochromatographic kit (Wampole™ Tox A/B Quik Chek). Surveillance data was collected from patients’ medical records to establish the demographic and clinical characteristics. The overall prevalence and incidence of CDI in UKMMC was 6.1% and 5.2 cases per 10 000 patient-days, respectively. Among nine CDI patients, 77.8% were males and 55.6% were Chinese. CDI was most common in medical wards (88.9%). The median age was 60 years and the median length of hospital stay was 13 days. Majority (88.9%) of CDI patients received antibiotics eight weeks prior to CDI. Penicillin-beta-lactamase inhibitors were the most common antecedent antibiotics. Five (55.6%) CDI patients received acid suppressant medications. The in-hospital mortality rate was 22.2%. In conclusion, the prevalence and incidence of CDI at UKMMC is relatively low and occurs sporadically.
Infection with Helicobacter pylori cagA-positive strains is associated with gastroduodenal diseases. The CagA protein is injected into gastric epithelial cells and supposedly induces morphological changes termed the 'hummingbird phenotype', which is associated with scattering and increased cell motility. The molecular mechanisms leading to the CagA-dependent morphological changes are only partially known. The present study was carried out to investigate the effect of CagA variants on the magnitude of gastric epithelial cell morphological changes. Recombinant 3' terminal domains of cagA were cloned and expressed in a gastric epithelial cell line and the hummingbird phenotype was quantified by microscopy. The 3' region of the cagA gene of Malaysian H. pylori isolates showed six sub-genotypes that differed in the structural organization of the EPIYA repeat sequences. The percentage of hummingbird cells induced by CagA increased with duration of transfection. The hummingbird phenotype was observed to be more pronounced when CagA with 4 EPIYA motifs rather than 3 or 2 EPIYA motifs was produced. The activity of different CagA variants in the induction of the hummingbird phenotype in gastric epithelial cells depends at least in part on EPIYA motif variability. The difference in CagA genotypes might influence the potential of individual CagAs to cause morphological changes in host cells. Depending on the relative exposure of cells to CagA genotypes, this may contribute to the various disease outcomes caused by H. pylori infection in different individuals.
Helicobacter pylori has been implicated as an aetiologic agent for type B chronic gastritis, peptic ulcer and gastric cancer. It is considered the most common bacterial infection in the world with approximately 50% of the population being infected. The majority of infected individuals are asymptomatic, with some developing gastritis only. However, chronic infection with H. pylori without antibiotic treatment predisposes infected individuals to the development of gastric cancer. The aim of this study is to determine active H. pylori infection among patients with symptoms of dyspepsia using three combinations of diagnostic methods. In this report, we studied 1,376 consecutive patients who underwent upper gastrointestinal endoscopy at Universiti Kebangsaan Malaysia Medical Center (UKMMC) for dyspepsia from the period January 1999 to December 2002. The classification of patient’s diagnosis was assessed by endoscopic and histological examination. The H. pylori status was determined by rapid urease test, histological examination or H. pylori culture. Presence of H. pylori infection was confirmed in 30.8% of patients with dyspepsia. H. pylori infection was more prevalent in older patients and in males compared to females. Patients with severe gastroduodenal diseases were more commonly infected with H. pylori. There was a significant difference in H. pylori prevalence among the different ethnic groups. Indians had the highest infection rate (45.4%), followed by Chinese (36.8%) and the lowest were seen in Malays (18.3%). This finding on determination of active H. pylori infection among patients with dyspepsia is consistent with serological studies that showed racial differences in H. pylori prevalence. However, the pattern of H. pylori infection does not reflect the prevalence of severe gastroduodenal diseases among different ethnic groups.
Antibiotic resistance is increasing worldwide, and it has been regarded as the main factor reducing the efficacy of Helicobacter pylori therapy. The aim of this study was to determine the phenotype and genotype of antibiotic-resistant strains of H. pylori in the Malaysian population and to evaluate the impact of antibiotic resistance to eradication outcome. One hundred and sixty-one H. pylori isolates were analysed in this study. Metronidazole, clarithromycin, fluoroquinolone, amoxicillin and tetracycline susceptibilities were determined by Etest. PCR followed by DNA sequencing was carried out to determine mutations. The medical records of the patients infected with resistant strains were reviewed to determine the eradication outcome. Metronidazole resistance was encountered in 36.6 % of H. pylori isolates, whereas clarithromycin and fluoroquinolone resistance was observed in 1.2 and 1.9 % of isolates, respectively. All strains tested were susceptible to amoxicillin and tetracycline. Frameshift and nonsense mutations in rdxA and frxA genes resulting in stop codons contributed to metronidazole resistance, which leads to reduced eradication efficacy. A2142G and A2143G mutations of 23S rRNA were identified as causing failure of the eradication therapy. Mutation at either codon 87 or 91 of the gyrA gene was identified in fluoroquinolone-resistant strains. However, the effect of resistance could not be assessed. This study showed that frameshift and nonsense mutations in rdxA or frxA genes and point mutations in the 23S rRNA affected the efficacy of H. pylori eradication therapy.
Methicillin-resistant Staphylococcus aureus (MRSA) has been prevalent in our hospital over the last three years. Differentiation among MRSA strains by DNA typing in addition to antibiotic resistance pattern surveillance is crucial in order to implement infection control measures. The aim of this study was to characterize MRSA isolates from patients admitted to Hospital Universiti Kebangsaan Malaysia (HUKM) by phenotypic (analyses of antibiotic susceptibility pattern) and genotypic (PFGE) techniques to determine the genetic relatedness of the MRSA involved and to identify endemic clonal profiles of MRSA circulating in HUKM. Seventy one MRSA strains collected between January to March 2000 from patients from various wards in HUKM were tested for antimicrobial resistance and typed by pulsed-field gel electrophoresis (PFGE). Four major types of PFGE patterns were identified (A, B, C and D) among MRSA strains. Two predominant PFGE types were recognised, Type A (59.2%) and Type B (33.8%). Most of these strains were isolated from ICU, Surgical wards and Medical wards. MRSA strains with different PFGE patterns appeared to be widespread among wards. Strains with the same antibiotype could be of different PFGE types. Most of isolates were resistant to ciprofloxacin, erythromycin, gentamicin and penicillin. One isolate with a unique PFGE pattern Type D and susceptible to gentamicin was identified as a different clone. Some isolates obtained from the same patient showed different PFGE subtypes suggesting that these patients were infected/colonized with multiple MRSA strains. PFGE analysis suggests that MRSA strains with different PFGE types was propagated within our hospital. The relationship between antibiotic susceptibility and PFGE patterns was independent. The ability of PFGE technique in differentiating our MRSA strains make it a method of choice for investigating the source, transmission and spread of nosocomial MRSA infection, and thus an appropriate control programme can be implemented to prevent the spread of MRSA infection.
Serratia marcescens is a well-known cause of nosocomial infections and outbreaks, particularly in immunocompromised patients with severe underlying disease. An outbreak due to S. marcescens infection was detected from 13 to 22 February 2001 at the intensive care unit (ICU) of our institution. We used pulsed-field gel electrophoresis (PFGE) typing to analyse the outbreak strains involved.
Antimicrobial resistance in Acinetobacter baumannii is a growing public health concern and an important pathogen in nosocomial infections. We investigated the genes involved in resistance to carbapenems and cephalosporins in clinical A. baumannii isolates from a tertiary medical centre in Malaysia. A. baumannii was isolated from 167 clinical specimens and identified by sequencing of the 16S rRNA and rpoB genes. The MIC for imipenem, meropenem, ceftazidime and cefepime were determined by the E-test method. The presence of carbapenemase and cephalosporinase genes was investigated by PCR. The isolates were predominantly nonsusceptible to carbapenems and cephalosporins (>70 %) with high MIC values. ISAba1 was detected in all carbapenem-nonsusceptible A. baumannii harbouring the blaOXA-23-like gene. The presence of blaOXA-51-like and ISAba1 upstream of blaOXA-51 was not associated with nonsusceptibility to carbapenems. A. baumannii isolates harbouring ISAba1-blaADC (85.8 %) were significantly associated with nonsusceptibility to cephalosporins (P<0.0001). However, ISAba1-blaADC was not detected in a minority (<10 %) of the isolates which were nonsusceptible to cephalosporins. The acquired OXA-23 enzymes were responsible for nonsusceptibility to carbapenems in our clinical A. baumannii isolates and warrant continuous surveillance to prevent further dissemination of this antibiotic resistance gene. The presence of ISAba1 upstream of the blaADC was a determinant for cephalosporin resistance. However, the absence of this ISAba1-blaADC in some of the isolates may suggest other resistance mechanisms and need further investigation.
Helicobacter pylori strains secrete a vacuolating cytotoxin (VacA), plays an important role for the development of peptic ulcer disease and gastro-duodenal diseases. vacA gene is responsible to regulate the activity of the vacuolating cytotoxin. The objective of this study was molecular detection of vacA gene and observes the vacuolating activity on human gastric adenocarcinoma (AGS) cells.
To characterise the cag pathogenicity island in Helicobacter pylori (H. pylori) isolates by analysing the strains' vacA alleles and metronidazole susceptibilities in light of patient ethnicity and clinical outcome.
New Delhi metallo-β-lactamase-1 (NDM-1) is a relatively recent carbapenemase enzyme that inactivates all β-lactam antibiotics with the exception of aztreonam. This study aims to ascertain the baseline prevalence and antibiotic susceptibility patterns of NDM-1-producing Enterobacteriaceae in a tertiary medical center in Malaysia.
Polymorphisms of Helicobacter pylori cagA and vacA genes do exist and may contribute to differences in H. pylori infection and gastroduodenal diseases among races in the Malaysian population. This study was conducted to characterize the polymorphisms in H. pylori cagA and vacA in Malaysian population.
The New Delhi metallo-β-lactamase-1 (NDM-1) enzyme is a plasmid-encoded enzyme that inactivates carbapenem antibiotics. This study aims to ascertain if the modified Hodge test (MHT) has a role in screening for NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility.
This study was conducted to determine the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Malaysian hospitals. A total of 264 MRSA isolates from eight hospitals were subjected to typing by pulsed-field gel electrophoresis (PFGE) of SmaI restricted DNA. Antibiotic disk susceptibility testing was also carried out to determine their resistance patterns. Thirty-one PFGE pattern types were identified. Three major pattern types A, ZC and K were found with type A the predominant profile in c. 80% of strains and present in all hospitals. Unlike type A, other DNA pattern types were unique to the hospitals in which they were isolated. PFGE type A also consisted of strains that were multiply antibiotic resistant. The presence of a single predominant PFGE type in Malaysian hospitals is an important finding which suggests that inter-hospital spread of MRSA had occurred frequently and regularly.
The objective of this study was to compare the rates of bacterial contamination of expressed breast milk (EBM) obtained by manual expression and breast pumps in mothers of very low birthweight (VLBW) infants (<1501 g). This was a randomized, controlled study carried out on 28 mothers of such babies and 92 specimens of EBM were collected: 41 specimens from 13 mothers assigned to the manual group and 51 specimens from 15 mothers in the breast-pump group. EBM was cultured quantitatively by the Miles and Misra method. Breast milk expressed by breast pumps (86.3% or 44/51 specimens) had a significantly higher rate of bacterial contamination than milk expressed by the manual method (61.0% or 25/41 specimens) (P= 0.005). When breast milk was expressed in the hospital, there was no significant difference in contamination rates between the two methods. When breast milk was expressed at home, the rates of bacterial contamination by staphylococci (P= 0.003) and Gram-negative bacilli (P= 0.002) were significantly higher in the breast-pump group than the manual group. In conclusion, the rate of bacterial contamination of EBM of mothers of VLBW infants was high, especially when EBM was obtained by the breast pump or when expression was carried out at home.
Helicobacter pylori infection of a distinct subtype of cagA may lead to different pathological manifestation. The aim of this study is to determine the presence of cagA gene and its variants in H. pylori infection among different ethnic groups and its effect on gastroduodenal diseases. Overall detection of cagA among the 205 clinical isolates of H. pylori was 94%. Variations in size of the 3' region of cagA gene were examined among 192 Malaysian H. pylori cagA-positive strains. Results showed that three cagA variants differing in fragment length of PCR products were detected and designated as type A (621-651bp), type B (732-735bp) and type C (525 bp). Although there was no association between any of the cagA subtypes with peptic ulcer disease (p>0.05), an association between cagA subtypes with a specific ethnic group was observed. Specific-cagA subtype A strains were predominantly isolated from Chinese compared to Malays and Indians (p<0.0005), and cagA subtype B strains were predominantly isolated from Malays and Indians compared to Chinese (p<0.05). The cagA type A strains of H. pylori is commonly found in the Chinese patients who have a higher risk of peptic ulcer disease, thus indicating that it could be used as an important clinical biomarker for a more severe infection.