Evaluation of the microbiological efficacy of cleaning agents for tracheostomy inner cannulas.

PURPOSE: Biofilms are a significant cause of morbidity in patients with indwelling medical devices. Biofilms pose a potential risk with reusable inner cannulas by increasing the risk of infections. Effective decontamination is thus vital in decreasing bioburden. The current guidelines for cleaning inner cannulas are varied, with multiple techniques being recommended, which are not supported by strong evidence. This randomized, controlled, cross-over study attempted to enumerate the bacterial count of inner cannulas used in tracheostomy patients (n = 60) pre-and post-decontamination with detergent (A) or sterile water (B). MATERIALS AND METHODS: The patients were randomly allocated to sequence A > B or B > A in 1:1 fashion. The saline flushing of the inner cannulas was plated on trypticase soy agar with 5 % sheep blood to enumerate the bacterial count. RESULTS: The mean ratio [Log (CFU)post/Log (CFU)pre]A/[Log (CFU)post/Log (CFU)pre]B based on 53 samples was 0.918 ± 0.470, two-sided 90 % confidence interval (CI) 0.812, 1.024. The equivalence criterion was met as the mean ratio after cleaning fell within the equivalence region of 0.8 and 1.25. CONCLUSION: This study demonstrated the microbiological efficacy of both detergent and sterile water in the decontamination of inner cannulas, and that sterile water was not less effective than detergent in reducing the bacterial load for safe re-use of inner cannulas. This has the potential to promote cost savings for patients with tracheostomy, both in the hospital and the community. The study findings may also be relevant in formulating tracheostomy care policies.

Clonal serotype 1c multidrug-resistant Shigella flexneri detected in multiple institutions by sentinel-site sequencing.

Shigella flexneri is a major diarrhoeal pathogen, and the emergence of multidrug-resistant S. flexneri is of public health concern. We report the detection of a clonal cluster of multidrug-resistant serotype 1c (7a) S. flexneri in Singapore in April 2022. Long-read whole-genome sequence analysis found five S. flexneri isolates to be clonal and harboring the extended-spectrum ß-lactamases bla CTX-M-15 and bla TEM-1. The isolates were phenotypically resistant to ceftriaxone and had intermediate susceptibility to ciprofloxacin. The S. flexneri clonal cluster was first detected in a tertiary hospital diagnostic laboratory (sentinel-site), to which the S. flexneri isolates were sent from other hospitals for routine serogrouping. Long-read whole-genome sequence analysis was performed in the sentinel-site near real-time in view of the unusually high number of S. flexneri isolates received within a short time frame. This study demonstrates that near real-time sentinel-site sequence-based surveillance of convenience samples can detect possible clonal outbreak clusters and may provide alerts useful for public health mitigations at the earliest possible opportunity.

Changes in serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates from adult patients in Asia: Emergence of drug-resistant non-vaccine serotypes.

This study was performed to investigate the serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae in Asian countries. A prospective surveillance study on S. pneumoniae collected from adult patients (≥50 years old) with invasive pneumococcal disease or community-acquired pneumonia was performed at 66 hospitals in Asian countries (Korea, China, Malaysia, Singapore, the Philippines, and Thailand) in 2012-2017. Serotyping and antimicrobial susceptibility tests of 850 pneumococcal isolates were performed. The proportions of isolates with serotypes covered by 13-valent pneumococcal conjugate vaccine (PCV13) were 37.0% in Korea, 53.4% in China, 77.2% in Malaysia, 35.9% in the Philippines, 68.7% in Singapore, and 60.2% in Thailand. Major serotypes were 19F (10.4%), 19A (10.1%), and 3 (8.5%) in 2012-2017, with different serotype distributions in each country. Macrolide resistance in pneumococci was high (66.8%) and prevalence of multidrug resistance (MDR) also remained high (50.8%). MDR non-PCV13 serotypes such as 11A, 15A, 35B, and 23A have emerged in Asian countries. This study showed the persistent prevalence of 19F and 19A with a noteworthy increase of certain non-PCV13 serotypes in Asian countries. High prevalence of macrolide resistance and MDR was also found in pneumococcal isolates. These data emphasize the need for continued surveillance of pneumococcal epidemiology in Asia in the post-pneumococcal vaccine era.

Development of a real-time assay to determine the frequency of qac genes in methicillin resistant Staphylococcus aureus.

PURPOSE: The emergence of antiseptic resistance and/or antiseptic-resistance genes in methicillin-resistant Staphylococcus aureus (MRSA) may result in failure of decolonization treatments. Plasmid-encoded efflux pump genes qacA/B and qacC (smr) confer tolerance to chlorhexidine and quaternary ammonium compounds. The objective of this study was to develop and validate a multiplex real time-PCR assay for detection of antiseptic-resistance genes, apply the assay on 200 MRSA isolates and explore if carriage of these genes was associated with resistance to topical antibiotics. METHODOLOGY: A SYBR-Green based multiplex real time-PCR assay was developed to detect qacA/B, qacC, and mecA (internal control) simultaneously. The multiplex assay was compared against conventional single-plex PCR followed by agarose gel electrophoresis, using DNA from the first 73 MRSA isolates, followed by multiplex testing of the remaining 127 MRSA isolates. All 200 MRSA isolates were tested for susceptibility to mupirocin, retapamulin, neomycin, bacitracin and octenidine. The genetic diversity of the isolates was investigated by spa-typing. RESULTS: The concordance between multiplex and conventional PCR, in assignments of qacA/B and qacC status were 99%(72/73) and 100%(73/73) respectively. Among 200 MRSA isolates, 48(24%) and 44(23%) were found to harbour qacA/B and qacC genes, respectively. These isolates remained susceptible to many common decolonization agents, except mupirocin. The predominant spa-types were t020 and t1081 (41 and 32 isolates respectively). CONCLUSION: The real-time assay performed acceptably for the detection of qac genes. A high prevalence of antiseptic-resistance genes were detected in the MRSA isolates in our population and appeared to be associated with spa-type t1081.