Epidemiology and Antimicrobial Susceptibility Patterns of Staphylococcus aureus Isolates from Clinical Specimens at Meru Teaching and Referral Hospital, Kenya

  1. Pharis Kaumbuthu
  2. Dorothy Kagendo
  3. Jane Rutto

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Abstract

Background

Staphylococcus aureus is an important bacterial pathogen responsible for a wide range of community- and healthcare-associated infections. The increasing prevalence of antimicrobial-resistant strains, particularly methicillin-resistant S. aureus (MRSA), has complicated treatment and increased the need for reliable facility-specific antimicrobial resistance surveillance. However, limited published data are available on the prevalence and antimicrobial susceptibility patterns of S. aureus at Meru Teaching and Referral Hospital (MeTRH), a major referral facility in eastern Kenya.

Objective

To determine the prevalence of S. aureus among clinical specimens processed at MeTRH and assess the antimicrobial susceptibility patterns and proportion of MRSA among confirmed isolates.

Methods

A retrospective descriptive cross-sectional study was conducted using microbiology laboratory records for clinical specimens submitted for bacteriological culture at MeTRH during the study period. A census approach was used, whereby all eligible laboratory records were included. Clinical specimens were processed using routine microbiological procedures, and suspected S. aureus isolates were identified using conventional methods and the VITEK® 2 Compact automated identification system. Antimicrobial susceptibility testing was performed using VITEK® 2 Compact, with interpretation based on Clinical and Laboratory Standards Institute criteria. Methicillin resistance was determined phenotypically using cefoxitin susceptibility as the surrogate marker. Data were analysed using frequencies and percentages.

Results

A total of 1,082 clinical specimens were analysed, of which 37 yielded S. aureus , giving an overall prevalence of 3.42%. Among the confirmed isolates, 21 (56.8%) were recovered from male patients and 16 (43.2%) from female patients. Pus was the predominant specimen type, accounting for 25 (67.6%) isolates, followed by other specimens at 8 (21.6%) and urine at 4 (10.8%). Antimicrobial susceptibility varied considerably. Resistance was highest to benzylpenicillin and amoxicillin, with 100% resistance among tested isolates. Resistance to amoxicillin-clavulanic acid was 75.0%, while 63.3% of isolates tested were resistant to oxacillin. Susceptibility was relatively high to gentamicin (82.8%), ciprofloxacin (77.3%) and clindamycin (75.0%). All isolates tested against linezolid and vancomycin were susceptible. Among 30 isolates with methicillin susceptibility results, 19 (63.3%) were classified as MRSA and 11 (36.7%) as methicillin-susceptible S. aureus (MSSA).

Conclusion

The prevalence of S. aureus among clinical specimens processed at MeTRH was relatively low; however, a substantial proportion of isolates demonstrated antimicrobial resistance, particularly to commonly used β-lactam antibiotics. The high proportion of MRSA is of clinical and public health importance. Routine antimicrobial susceptibility testing, hospital-specific antibiograms, antimicrobial stewardship and strengthened infection prevention and control measures are recommended to support appropriate treatment and limit the spread of resistant S. aureus .

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  1. PREreview

    This Zenodo record is a permanently preserved version of a Structured PREreview. You can view the complete PREreview at https://prereview.org/reviews/23111619.

    Does the introduction explain the objective of the research presented in the preprint? Yes
    Are the methods well-suited for this research? Somewhat inappropriate The duration of the study was not capture in the work The study did not assess important patient-related factor(s) such as previous antibiotic exposure before sample collection.
    Are the conclusions supported by the data? Highly supported
    Are the data presentations, including visualizations, well-suited to represent the data? Somewhat appropriate and clear
    How clearly do the authors discuss, explain, and interpret their findings and potential next steps for the research? Very clearly They provided clear interpretation of their findings and their explanation is in line with their objectives
    Is the preprint likely to advance academic knowledge? Moderately likely by providing necessary data and finding on the study area, they have contributed in filling the geographical gap in the study area.
    Would it benefit from language editing? No The language is clear and understanding
    Would you recommend this preprint to others? Yes, it's of high quality
    Is it ready for attention from an editor, publisher or broader audience? Yes, as it is

    Competing interests

    The authors declare that they have no competing interests.

    Use of Artificial Intelligence (AI)

    The authors declare that they did not use generative AI to come up with new ideas for their review.

  2. Version published to 10.64898/2026.09.09.26362593 on medRxiv