Unexpected High Prevalence of qacA/B and smr Genes Among Staphylococcus spp Isolates From Individuals Attending a Sexually Transmitted Infections Clinic
Bibliographic record
Abstract
Background. Plasmid-borne qacA/B and smr genes encode for multidrug efflux pumps and are associated with reduced susceptibility to quaternary ammonium compounds (QAC) and chlorhexidine (CHX). As part of a prevalence survey of Staphylococcus aureus (SA) carriage among people attending a sexually transmitted infection (STI) clinic, we analyzed the prevalence of qac A/B and smr genes among Staphylococcus spp isolates. Methods. Following Ethics Board approval, written informed consent was obtained and swabs from nares, throat, axilla, groin, perineum-perianal, vaginal, upper back and interdigital web spaces were collected from a STI clinic population over a 5-month period. Following broth enrichment, SA and coagulase-negative staphylococci (CNS) isolates were identified using standard laboratory procedures. Identification of qac A/B and smr genes was done with a novel multiplex PCR assay with 6 targets: 16s rRNA, nuc (to distinguish SA from CNS), qacA/B, smr, mupA, and mecA. Results. A sample of 265 Staphylococcus spp isolates from 204 individuals was analyzed; 155 (58.5%) were methicillin-susceptible SA (MSSA), 94 (35.4%) were methicillin-susceptible CNS (MS-CNS) and 16 (6%) methicillin-resistant CNS (MR-CNS), no MRSA isolates were found. The overall prevalence of any of qacA/B and/or smr genes was 12.8%; the highest prevalence was among MR-CNS isolates compared with MS-CNS (56.2%, 9 of 16 versus 20.2%, 19 of 94; p < 0.01) followed by 3.8% (6 of 155) in MSSA. Combinations of qacA/B and smr genes were only seen among CNS isolates, more commonly in MS-CNS versus MR-CNS (8.5%, 8 of 94 versus 1 of 16, 6.2%; p = NS). Positivity of the mup gene was only observed in 3 isolates (0.1%), always in combination with other genes. Conclusion. We found a high prevalence of qacA/B genes in Staphylococcus spp isolates among people attending a STI clinic compared to very low rates (0–2%) reported in community ambulatory settings. This is one of the first studies documenting the presence of qacA/B and smr genes in staphylococci in a STI population. Genes that may confer resistance to QACs and CHX among isolates in an ambulatory setting are of concern since they may serve as an unrecognized reservoir for their introduction into the hospital setting. Further studies in other STI clinic populations would be of value to corroborate our findings. Disclosures. All authors: No reported disclosures.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".