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Background. Pseudomonas aeruginosa is ubiquitous, has intrinsic antibiotic resistance mechanisms, and is associated with serious hospital-associated infections. It has evolved from being a burn wound infection into a major nosocomial threat. In this study, we compared and correlated the antimicrobial resistance, virulence traits and clonal relatedness between clinical and fresh water environmental isolates of P. aeruginosa. Methods. 219 P. aeruginosa isolates were studied: (a) 105 clinical isolates from 1977 to 1985 (n D 52) and 2015 (n D 53), and (b) 114 environmental isolates from different fresh water sources. All isolates were subjected to ERIC-PCR typing, antimicrobial susceptibility testing and virulence factor genes screening. Results. Clinical and environmental isolates of P. aeruginosa were genetically heteroge-nous, with only four clinical isolates showing 100% identical ERIC-PCR patterns to seven environmental isolates. Most of the clinical and environmental isolates were sensitive to almost all of the antipseudomonal drugs, except for ticarcillin/clavulanic acid. Increased resistant isolates was seen in 2015 compared to that of the archived isolates; four MDR strains were detected and all were retrieved in 2015. All clinical isolates retrieved from 1977 to 1985 were susceptible to ceftazidime and ciprofloxacin; but in comparison, the clinical isolates recovered in 2015 exhibited 9.4% resistance to ceftazidime and 5.7% to ciprofloxacin; a rise in resistance to imipenem (3.8% to 7.5%), piperacillin (9.6% to 11.3%) and amikacin (1.9% to 5.7%) and a slight drop in resistance rates to piperacillin/tazobactam (7.7% to 7.5%), ticarcillin/clavulanic acid (19.2% to 18.9%), meropenem (15.4% to 7.5%), doripenem (11.5% to 7.5%), gentamicin (7.7% to 7.5%) and netilmicin (7.7% to 7.5%). Environmental isolates were resistant to piperacillin/tazobactam (1.8%), ciprofloxacin (1.8%), piperacillin (4.4%) and carbapenems (doripenem 11.4%, meropenem 8.8% and imipenem 2.6%). Both clinical and environmental isolates showed high prevalence of virulence factor genes, but none were detected in 10 (9.5%) clinical and 18 (15.8%) environmental isolates. The exoT gene was not detected in any of the clinical isolates. Resistance to carbapenems (meropenem, doripenem and imipenem), fi-lactamase inhibitors (ticarcillin/clavulanic acid and piperacillin/tazobactam), piperacillin, ceftazidime and ciprofloxacin was observed in some of the isolates without virulence factor genes. Five virulence-negative isolates were susceptible to all of the antimicrobials. Only one MDR strain harbored none of the virulence factor genes. Conclusion. Over a period of 30 years, a rise in antipseudomonal drug resistance particularly to ceftazidime and ciprofloxacin was observed in two hospitals in Malaysia. [ABSTRACT FROM AUTHOR]

The Gram-negative saprophyte Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease which is endemic in Southeast Asia and northern Australia. This bacterium possesses many virulence factors which are thought to contribute to its survival and pathogenicity. Using a virulent clinical isolate of B. pseudomallei and an attenuated strain of the same B. pseudomallei isolate, 6 genes BPSL2033, BP1026B I2784, BP1026B I2780, BURPS1106A A0094, BURPS1106A 1131, and BURPS1710A 1419 were identified earlier by PCR-based subtractive hybridization. These genes were extensively characterized at the molecular level, together with an additional gene BPSL3147 that had been identified by other investigators. Through a reverse genetic approach, single-gene knockout mutants were successfully constructed by using site-specific insertion mutagenesis and were confirmed by PCR. BPSL2033::Km and BURPS1710A 1419::Km mutants showed reduced rates of survival inside macrophage RAW 264.7 cells and also low levels of virulence in the nematode infection model. BPSL2033::Km demonstrated weak statistical significance (P = 0.049) at 8 hours after infection in macrophage infection study but this was not seen in BURPS1710A 1419::Km. Nevertheless, complemented strains of both genes were able to partially restore the gene defects in both in vitro and in vivo studies, thus suggesting that they individually play a minor role in the virulence of B. pseudomallei. [ABSTRACT FROM AUTHOR]

Burkholderia pseudomallei is the causative agent of melioidosis. We initiated this investigation with a virulent and an attenuated strain of B. pseudomollei. Pulsed-field gel electrophoresis was carried out initially for macrogenomic com- parison of both strains of B. pseudomal!ei. However, the pulsotypes obtained were identical and therefore we applied a subtractive hybridization technique to distinguish and determine the possible differences between the two strains. Six virulence strain-specific DNA fragments were obtained and the encoding homolog proteins were identified as a xenobiotic-responsive element family of transcriptional regulator, a hypothetical protein, an unknown protein, a plasmid recombination enzyme, a regulatory protein and a putative hemolysin activator protein. A combination of at least three of these determinants was identified in 45 clinical isolates when screening was carried out with self-designed multiplex PCR targeting the six putative virulent determinants. Our data demonstrated that different combinations of the six putative virulence genes were present in the clinical isolates indicating their probable role in the pathogenesis of B. pseudomallel infections. [ABSTRACT FROM AUTHOR]

Background: Neisseria meningitidis (N. meningitidis) remains the leading worldwide cause of acute bacterial meningitis and fatal sepsis in healthy individuals. Materials and Methods: A total of 12 cases of N. meningitidis from patients with invasive meningococcal infections in University of Malaya Medical Centre, Kuala Lumpur during the years 1987-2004 were reviewed together with details of age, sex, disease, risk factors treatment and outcome of these patients. Results: Their ages ranged from 10 months to 64 years (median age 29.75 years). The male to female ratio was 1.42:1. Fever, neck stiffness, headache, vomiting and confusion were predominant symptoms. Upper respiratory tract viral infection and Hajj pilgrimage were directly associated with invasive meningococcal disease. Penicillin or ceftriaxone or both in some cases were administered as empirical therapy. All isolates were sensitive to penicillin, ceftriaxone, chloramphenicol and rifampicin. The case fatality ratio was 1:4. One Hajj pilgrim died despite having received polyvalent meningococcal vaccine. Amongst the survivors, two patients had neurological deficit, hearing loss and arthritis. Conclusion: Early antimicrobial therapy has been shown to reduce these adverse outcomes. Clinicians need to be alerted to the presence of the disease in the community and the disease should be made notifiable within 24 hours of detection both for early treatment of cases and to facilitate contact tracing, institution of prophylactic treatment and prevention of secondary cases. [ABSTRACT FROM AUTHOR]

Background: In Malaysia, Shigella spp. was reported to be the third commonest bacterial agent responsible for childhood diarrhoea. Currently, isolation of the bacterium and confirmation of the disease by microbiological and biochemical methods remain as the "gold standard". This study aimed to detect the prevalence of four Shigella virulence genes present concurrently, in randomly selected Malaysian strains via a rapid multiplex PCR (mPCR) assay. Methods: A mPCR assay was designed for the simultaneous detection of chromosomal- and plasmid-encoded virulence genes (set1A, set1B, ial and ipaH) in Shigella spp. One hundred and ten Malaysian strains (1997-2000) isolated from patients from various government hospitals were used. Reproducibility and sensitivity of the assay were also evaluated. Applicability of the mPCR in clinical settings was tested with spiked faeces following preincubation in brain heart infusion (BHI) broth. Results: The ipaH sequence was present in all the strains, while each of the set1A, set1B and ial gene was present in 40% of the strains tested. Reproducibility of the mPCR assay was 100% and none of the non-Shigella pathogens tested in this study were amplified. The mPCR could detect 100 colony-forming units (cfu) of shigellae per reaction mixture in spiked faeces following preincubation. Conclusions: The mPCR system is reproducible, sensitive and is able to identify pathogenic strains of shigellae irrespective of the locality of the virulence genes. It can be easily performed with a high throughput to give a presumptive identification of the causal pathogen. [ABSTRACT FROM AUTHOR]

The effect of cows' milk protein (CMP) on the mucosal disaccharidases was investigated in 23 infants with acute infective enteritis. Jejunal biopsies performed before and after cows' milk provocation were subjected to histological examination and to mucosal disaccharidase enzyme (lactase, sucrase, and maltase) analyses. After milk challenge, changes in mucosal histology were observed in 18 infants, in 17 of them the levels of all 3 mucosal disaccharidases were much reduced. 10 of these infants developed diarrhoea and, in 6, the stools were positive for reducing sugar. It is concluded that CMP has a deleterious effect on the jejunal mucosa of young infants recovering from infective enteritis, so that in the management of young infants with sugar intolerance secondary to infective enteritis, CMP and lactose should be excluded from the diet. [ABSTRACT FROM AUTHOR]

The possible role of cows' milk protein in prolonging diarrhoea in very young infants with acute infective enteritis was studied in 14 infants, 9 under the age of 2 months and 5 older than 6 months. Bacterial pathogens were isolated from the stools of 4 infants from the younger age group. After appropriate initial treatment the infants were maintained on a cows' milk protein-free formula. 6 weeks later jejunal biopsies were performed before and 24 hours after challenge with a low lactose cows' milk protein formula. The immunoglobulin and complement levels in the serum and duodenal juice were also estimated at these times. Attempts to isolate bacterial and viral pathogens in stools were again made in all patients. The 5 older infants clinically tolerated cows' milk protein and their pre- and postchallenge jejunal biopsies were within normal limits. However, significant histological changes were observed in the postchallenge jejunal biopsies of all 9 infants under 2 months of age. In addition, 5 of these infants developed diarrhoea. This suggests that the jejunal mucosa of very young infants previously fed a cows' milk protein-based formula and who contract infective enteritis suffers damage when rechallenged with cows' milk protein. [ABSTRACT FROM AUTHOR]