Impact of IsaA Gene Disruption: Decreasing Staphylococcal Biofilm and Alteration of Transcriptomic and Proteomic Profiles.

Staphylococcus aureus expresses diverse proteins at different stages of growth. The immunodominant staphylococcal antigen A (IsaA) is one of the proteins that is constitutively produced by S. aureus during colonisation and infection. SACOL2584 (or isaA) is the gene that encodes this protein. It has been suggested that IsaA can hydrolyse cell walls, and there is still need to study isaA gene disruption to analyse its impact on staphylococcal phenotypes and on alteration to its transcription and protein profiles. In the present study, the growth curve in RPMI medium (which mimics human plasma), autolytic activity, cell wall morphology, fibronectin and fibrinogen adhesion and biofilm formation of S. aureus SH1000 (wildtype) was compared to that of S. aureus MS001 (isaA mutant). RNA sequencing and liquid chromatography-tandem mass spectrometry were carried out on samples of both S. aureus strains taken during the exponential growth phase, followed by bioinformatics analysis. Disruption of isaA had no obvious effect on the growth curve and autolysis ability or thickness of cell walls, but this study revealed significant strength of fibronectin adherence in S. aureus MS001. In particular, the isaA mutant formed less biofilm than S. aureus SH1000. In addition, proteomics and transcriptomics showed that the adhesin/biofilm-related genes and hemolysin genes, such as sasF, sarX and hlgC, were consistently downregulated with isaA gene disruption. The majority of the upregulated genes or proteins in S. aureus MS001 were pur genes. Taken together, this study provides insight into how isaA disruption changes the expression of other genes and has implications regarding biofilm formation and biological processes.

COVID-19 in Malaysia: exposure assessment and prevention practices among healthcare workers at a teaching hospital.

INTRODUCTION: During the second wave of the coronavirus disease 19 (COVID-19) pandemic, Malaysia reported several COVID-19 clusters related to healthcare workers. Thus, addressing and understanding the risk of exposure in healthcare workers is important to prevent future infection and reduce secondary COVID-19 transmission within the healthcare settings. In this study, we aim to assess exposure and prevention practices against COVID-19 among healthcare workers at the Hospital Canselor Tuanku Muhriz, a university teaching hospital based in Kuala Lumpur, Malaysia. METHODOLOGY: A total of 571 healthcare workers at COVID-19 and non-COVID-19 wards as well as the emergency department and laboratory staff at COVID-19 testing labs were recruited. The presence of novel human coronavirus (SARS-CoV-2) and IgM/IgG antibodies were confirmed in all healthcare workers. The healthcare workers responded to an online Google Forms questionnaire that evaluates demographic information and comorbidities, exposure and adherence to infection prevention and control measures against COVID-19. Descriptive analysis was performed using Statistical Package for the Social Sciences 24.0. RESULTS: Three healthcare workers (0.5%) tested positive for SARS-CoV-2, while the remaining 568 (99.5%) were negative. All were negative for IgM and IgG antibodies during recruitment (day 1) and follow-up (day 15). More than 90% of the healthcare workers followed infection prevention and control practices recommendations regardless of whether they have been exposed to occupational risk for COVID-19. CONCLUSIONS: The healthcare workers' high level of adherence to infection prevention practices at this hospital helped reduce and minimize their occupational exposure to COVID-19.

Non-tuberculous mycobacterium bacteraemia in a pregnant systemic lupus erythematosus (SLE) patient: a case review and pooled case analysis.

Non-tuberculous mycobacteria (NTM) are recognized as an important cause of human diseases and infections. It is commonly known to cause infections of the skin, soft tissue infections, and pulmonary infection as well as bacteraemia. We report a challenging case of severe mycobacterium abscessus bacteraemia in a pregnant lady with active systemic lupus erythematous (SLE). A comprehensive literature review of NTM infection among SLE patients was also performed, and pooled analysis of the reported cases, including our case, was done to determine the clinical characteristics and factors associated with poor outcome of NTM infection.

Molecular detection of the New Delhi metallo-ß-lactamase-1 gene in Enterobacteriaceae isolates in a tertiary medical centre.

BACKGROUND: New Delhi metallo-ß-lactamase-1 (NDM-1) is a relatively recent carbapenemase enzyme that inactivates all ß-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. METHODS: Over a period of one year, all Enterobacteriaceae isolates from all clinical specimens with reduced susceptibility to at least one carbapenem and resistance to at least one third generation cephalosporin were subjected to antibiotic susceptibility testing by disk diffusion and molecular detection of the NDM-1 gene by single-target PCR followed by gel electrophoresis. RESULTS: A total of 13,098 Enterobacteriaceae isolates were screened and 63 (0.48%) had reduced susceptibility to at least one carbapenem. Of this 63, 18 (29%) were NDM-1-positive. Of this 18, 16 (89.0%) were Klebsiella pneumoniae, one (5.5%) was Escherichia coli and one (5.5%) was Klebsiella ornithinolytica. Reduced susceptibility to at least one aminoglycoside was seen in 17 (94%) of the NDM-1-positive isolates. All 18 (100%) had reduced susceptibility to ertapenem and were resistant to all the second and third generation cephalosporin antibiotics tested. CONCLUSION: The prevalence of NDM-1-producing Enterobacteriaceae among all the Enterobacteriaceae isolates in our institution is low (0.14%) and screening for the NDM-1 gene is best performed using ertapenem-impregnated disks.

INFLUENZA VACCINATION UPTAKE AMONG HEALTHCARE WORKERS AT A MALAYSIAN TEACHING HOSPITAL.

Annual influenza vaccination is the most important preventive strategy against influenza illness in healthcare workers (HCWs), who could acquire influenza from and transmit influenza to patients and other HCWs. Despite the well established benefits and strong recommendations for influenza vaccination for all HCWs, influenza vaccination uptake at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) for the past 3 years has been low and is decreasing. We aimed to determine the factors associated with influenza vaccination uptake among HCWs at UKMMC. We conducted a cross sectional study via questionnaire among 211 randomly selected HCWs, consisting of 106 HCWs who were vaccinated in 2011 and 105 HCWs who were not vaccinated in 2010 or 2011. We had a 100% response rate. Influenza vaccination uptake was significantly associated with age and previous vaccination history, with older HCWs being more likely to be vaccinated (adjusted OR = 12.494; 95% CI:6.278-24.863; p < 0.001) and HCWs with previous vaccination history being more likely to be vaccinated (adjusted OR = 1.038; 95% CI:1.001-1.077; p = 0.045). Influenza vaccination uptake was not associated with gender (p = 0.926) or job category (p = 0.220). Publicity at the workplace was the main source of information about the vaccine (51.2% of respondents), followed by colleagues (29.9%). Despite the low uptake, 85.3% of respondents believed influenza vaccination was important for disease prevention. The most common reason given for vaccination was protection against influenza infection (73.6%). The most common reason for not having the vaccine was time constraints (56.2%). An evidenced-based strategy needs to be developed to improve vaccine uptake or having mandatory vaccination.

Extremely high prevalence of antiseptic resistant Quaternary Ammonium Compound E gene among clinical isolates of multiple drug resistant Acinetobacter baumannii in Malaysia.

BACKGROUND: Antiseptics are commonly used for the management of MDR (multiple drug resistance) pathogens in hospitals. They play crucial roles in the infection control practices. Antiseptics are often used for skin antisepsis, gauze dressing, preparation of anatomical sites for surgical procedure, hand sterilization before in contact with an infected person, before an invasive procedure and as surgical scrub. METHODS: We screened 122 multiple drug resistant Acinetobacter baumannii (MDRAB) isolated from admitted patients in one of the tertiary care hospital in Malaysia for the presence of antiseptic resistant genes qacA and qacE (Quaternary Ammonium Compound) and susceptibility towards chlorhexidine (CLX), benzalkonium (BZK) and benzethonium (BZT). RESULTS: Eighty-nine (73%) isolates harboured qacE gene, while none were positive for qacA. The MIC ranged from 0.2 to 0.6 for CLX, 0.02 to 0.2 for BZK and 0.04 to 0.2 µg/mL for BZT. The highest number of qacE positive isolates were obtained from surgery (n = 24; 27%; p < 0.05), followed by medical ward (n = 23; 25.8%) and ICU (n = 21; 23.6%). Majority of the isolates from wound swabs (n = 33; 37%), T/aspirate (n = 16; 18%) and tissue (n = 10; 11.2%) harboured the qacE genes. CONCLUSION: The present investigation showed high prevalence of qacE gene among the studied isolates. Antiseptics are important components of infection control, continuous monitoring of antiseptics use in the hospital is cautioned.

Screening for New Delhi metallo-ß-lactamase-1 in Enterobacteriaceae: Is there a role for the modified Hodge test?

OBJECTIVE: The New Delhi metallo-ß-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. METHODS: Over a period of one year, all Enterobacteriaceae isolates from all clinical specimens with reduced susceptibility to at least one carbapenem were subjected to MHT and conventional polymerase chain reaction (PCR) detection of the NDM-1 gene. RESULTS: A total of 13,098 Enterobacteriaceae isolates were screened and 63 (0.48%) had reduced susceptibility to at least one carbapenem. Out of the 63 isolates, 45 (71.4%) were MHT-positive. The NDM-1 gene was detected in 18 of the 63 isolates (28.6%). All 18 PCR-positive isolates were also MHT-positive. Thus, the sensitivity and specificity of the MHT in detecting NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility are 100% and 40%, respectively. CONCLUSION: The MHT is a useful test to screen for the presence of NDM-1 in Enterobacteriaceae with reduced carbapenem susceptibility. However, due to its rather low specificity, all MHT-positive isolates should be subjected to alternative tests (e.g. PCR) for confirmation, especially if other types of carbapenemases (e.g. KPC) are prevalent.

Antibiogram for haemodialysis catheter-related bloodstream infections.

Background. Haemodialysis (HD) catheter-related bloodstream infections (CRBSIs) are a major complication of long-term catheter use in HD. This study identified the epidemiology of HD CRBSIs and to aid in the choice of empiric antibiotics therapy given to patients with HD CRBSIs. Methods. Patients with HD CRBSIs were identified. Their blood cultures were performed according to standard sterile technique. Specimens were sent to the microbiology lab for culture and sensitivity testing. Results were tabulated in antibiograms. Results. 18 patients with a median age of 61.0 years (IQR: 51.5-73.25) were confirmed to have HD CRBSIs based on our study criteria. Eight (44.4%) patients had gram-negative infections, 7 (38.9%) patients gram-positive infections, and 3 (16.7%) patients had polymicrobial infections. We noted that most of the gram-negative bacteria were sensitive to ceftazidime. Unfortunately, cloxacillin resistance was high among gram-positive organisms. Coagulase-negative Staphylococcus and Bacillus sp. were the most common gram-positive organisms and they were sensitive to vancomycin. Conclusion. Our study revealed the increased incidence of gram-negative organism in HD CRBSIs. Antibiogram is an important tool in deciding empirical antibiotics for HD CRBSIs. Tailoring your antibiotics accordingly to the antibiogram can increase the chance of successful treatment and prevent the emergence of bacterial resistance.

Community-acquired methicillin-resistant Staphylococcus aureus in a Malaysian tertiary centre.

Abstract. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a pathogen recognized to be distinct in both phenotype and genotype from hospital-acquired MRSA. We have identified CA-MRSA cases in Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, including their antibiotic susceptibility patterns and genotypic characteristics. Cases were identified during January to December 2009 from routine clinical specimens, where culture and antibiotic susceptibility results yielded pauci-resistant MRSA isolates suspected as being CA-MRSA. The patients' clinical data were collected and their specimens were sent for molecular confirmation and analysis. Five cases of CA-MRSA were identified, which had a multi-sensitive pattern on antibiotic susceptibility tests and were resistant to only penicillin and oxacillin. All cases were skin and soft-tissue infections, including diabetic foot with gangrene, infected scalp hematoma, philtrum abscess in a healthcare worker, thrombophlebitis complicated with abscess and infected bedsore. All five cases were confirmed MRSA by detection of mecA. SCCmec typing (ccr and mec complex) revealed SCCmec type IV for all cases except the infected bedsore case. Panton-Valentine leukocidin gene was positive in all isolates. As clinical features among methicillin-sensitive Staphylococcus aureus, CA-MRSA and "nosocomial CA-MRSA" are indistinct, early recognition is necessary in order to initiate appropriate antibiotics and infection control measures. Continual surveillance of pauci-resistant MRSA and molecular analysis are necessary in order to identify emerging strains as well as their epidemiology and transmission, both in the community and in healthcare setting.