Susceptibility of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) to chlorhexidine digluconate, octenidine dihydrochloride, polyhexanide, PVP-iodine and triclosan in comparison to hospital-acquired MRSA (HA-MRSA) and community-aquired MRSA (CA-MRSA): a standardized comparison

Rapid visualization molecular fluorescence detection of methicillin-resistant Staphylococcus aureus using the multiplex MIRA-qPCR method

Multidrug-resistant (MDR) bacterial infections constitute a major public health problem worldwide. A rapid method for the detection of methicillin-resistant Staphylococcus aureus (MRSA) is critical for the timely prevention of bacterial infections and the accurate clinical use of drugs. The nuc and mecA genes are potentially indicative of MRSA infection and in this study, a multiplex molecular fluorescence multi-enzyme isothermal rapid amplification visual assay was proposed and established. The method is capable of detecting MRSA at 17 min, 40°C amplification, and is well differentiated from common clinical bacteria in specific assays, with 500 colony-forming units (CFU) mL-1 of MRSA detected under optimal conditions. This method has excellent diagnostic capabilities versus classical methods to detect clinical samples and shows potential in the identification of pathogenic microorganisms in a clinical setting.

Clinical Evidence for the Use of Octenidine Dihydrochloride to Prevent Healthcare-Associated Infections and Decrease Staphylococcus aureus Carriage or Transmission-A Review

BACKGROUND

The antiseptic agent octenidine dihydrochloride (OCT) is used for skin preparation, for Staphylococcus aureus decolonization, and within bundles for the prevention of catheter-related or surgical site infections (SSIs). Here, we review the evidence for the effects of OCT from clinical studies.

METHODS

Review of studies published in the Medline, Scopus, and Cochrane databases until August 2022, performed in clinical settings and reporting on effects of OCT on S. aureus carriage/transmission, SSI prevention, and prevention of intensive care unit (ICU)-related or catheter-related bloodstream and insertion site infections.

RESULTS

We included 31 articles. The success of S. aureus decolonization with OCT-containing therapies ranged between 6 and 87%. Single studies demonstrated that OCT application led to a reduction in S. aureus infections, acquisition, and carriage. No study compared OCT for skin preparation before surgical interventions to other antiseptics. Weak evidence for the use of OCT for pre-operative washing was found in orthopedic and cardiac surgery, if combined with other topical measures. Mostly, studies did not demonstrate that daily OCT bathing reduced ICU-/catheter-related bloodstream infections with one exception.

CONCLUSIONS

There is a need to perform studies assessing the clinical use of OCT compared with other antiseptics with respect to its effectiveness to prevent nosocomial infections.

Phenotypic and Molecular Detection of Antiseptic Resistance Genes among Clinical Staphylococcus aureus Isolates During COVID-19 Pandemic

The coronavirus disease (COVID-19) pandemic has expanded the use of chlorhexidine digluconate, a biocide frequently used in hospitals, to inhibit the spread of infection. Genes responsible for resistance against the quaternary ammonium compound qac in Staphylococcus aureus isolates have been shown to confer tolerance to a number of biocidal chemicals, including chlorhexidine. The aim of this study was to determine the occurrence of antiseptic resistance genes (qacA/B and qacC) in clinical isolates of methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). The study also aimed to investigate the association between the presence of the mecA, qacA/B, and qacC genes in MRSA isolates and the susceptibility of the isolates to chlorhexidine to evaluate its future use in the Theodor Bilharz Research Institute (TBRI) hospital, following the Centers for Disease Control and Prevention recommendations for patients with MRSA. S. aureus isolates (n = 100) were collected from inpatients and outpatients at TBRI. A minimal inhibitory concentration of chlorhexidine was also detected. Polymerase chain reaction was used to detect the mecA, qacA/B, and qacC genes. The results revealed that 84% of S. aureus isolates were MRSA. MRSA (61.9%) and MSSA (68.8%) isolates were susceptible to chlorhexidine. The qacA/B gene was more dominant, being detected in 34%, while qacC was detected in only 5% of S. aureus isolates. All S. aureus isolates with reduced susceptibility to chlorhexidine harbored either the qacA/B or qacC genes. The clinical use of chlorhexidine may continue to increase, emphasizing the significance of continuous caution underlining the emergence of new clones with reduced susceptibility and avoiding antiseptic misuse.

Improving povidone-iodine and iodine preparations for patch testing

BACKGROUND

Allergy evaluation by patch testing with povidone-iodine (PVP-I) or iodine remains challenging, because current patch test preparations frequently lead to false-positive or irritant skin reactions.

OBJECTIVES

To investigate different preparations for iodine patch tests and to assess their clinical relevance with repeated open application tests (ROATs).

METHODS

We monocentrically analyzed 95 patients with suspected allergy to disinfectants in retrospect who underwent parallel iodine patch testing with four preparations: PVP-I 2% aq., 5% aq., 10% aq., and iodine 0.5% pet.

RESULTS

In 27 of 95 patients (28.4%), we found positive reactions to one of the four test preparations. After ROATs in 22 of these 27 positively tested individuals, only one patient was diagnosed with iodine allergy. In contrast, 31 of 95 patients (32.6%) showed irritant or questionable patch test reactions on day 2 (D2) and/or D3 and/or D7 to one or more test preparations. Testing with PVP-I 2% aq. resulted in the lowest number of doubtful skin reactions while detecting the single allergic patient.

CONCLUSION

PVP-I 2% aq. was found to be the optimal patch test preparation. In general, iodine allergy appears to be substantially overestimated, and positive patch test responses to iodine should prompt an urgent ROAT for confirmation before diagnosing iodine allergy.