Skip to main content
Download PDF
  • Research Note
  • Open access
  • Published:

Isolation and characterization of methicillin-resistant Staphylococcus aureus from bovine mastitis in North West Cameroon: public health implications

BMC Research Notes volume 17, Article number: 389 (2024) Cite this article

Abstract

Objectives

Methicillin-resistant Staphylococcus aureus (MRSA) is a zoonotic pathogen that poses a serious threat to veterinary and public health worldwide. We investigated mastitis milk samples for contamination with MRSA and also characterized the MRSA isolates by investigating antimicrobial resistance and virulence factors.

Result

We confirmed MRSA in 69 of 201 (34.3%) S. aureus isolates recovered from a total of 300 samples. Of the 69 MRSA, 19 (27.5%) were from subclinical cases, while 50 (72.5%) were from clinical cases. The MRSA showed high resistance to penicillin (100%), ampicillin (100%), trimethoprim (69.6%), and tetracycline (69.6%) while susceptibility was observed for gentamicin (100%), vancomycin (95.7%), and ciprofloxacin (91.3%). Most isolates (65.2%, 45/69) were multidrug resistant. Thirteen antibiotypes (A1-A13) were identified and the most prevalent was A8 (TMPRERTETRAMPRPR)). All MRSA produced haemolysins, caseinase, and coagulase. Lipase, gelatinase and lecithinase were found in 97.1%, 94.2% and 91.3% of isolates respectively. Genotyping revealed coa (100%) and spa (68.1%) genes. We recommend educating dairy farmers on the public health implications of consuming unpasteurized raw milk and the implementation of proper hygiene practices in dairy farms.

Peer Review reports

Introduction

The contamination of products of animal origin, such as milk, by Staphylococcus aureus is a public health hazard [1]. This opportunistic zoonotic bacterium commonly colonizes the skin and mucosa of livestock, particularly dairy cows with subclinical or clinical mastitis. The bacterium causes various diseases in humans ranging from mild skin infections to systemic infections such as pneumonia and meningitis [2]. A strain of S. aureus that develops resistance to the antibiotic methicillin, is referred to as methicillin-resistant S. aureus (MRSA). Methicillin-resistant Staphylococcus aureus is a notorious virulent biovar considered a global public health threat [3].

Some studies have linked the high prevalence of MRSA contamination in dairy farms to excessive and empirical administration of antibiotics in the treatment of dairy cows and poor sanitation management during milking [4]. Contamination of milk can occur during collection from the udder and also from the hands of farmers during milking. Hence poor hygiene practices in dairy farms increase the risk of milk contamination with MRSA [4, 5].

Initially, MRSA was thought to be confined to the hospital environment where a mortality rate of up to 20% has been reported [6]. The burden of MRSA infections has additionally been amplified by the emergence and spread of community- and livestock-acquired MRSA leading to difficulty in defining the boundary between hospital–community-livestock transmission [7]. Strains of MRSA are a significant public health concern that affects humans and animals, with environmental contamination facilitating their spread. Addressing this problem is urgent and requires knowledge of its reservoirs in the healthy population, animals and the environment at national and international levels to support effective ‘One Health’ prevention and control strategies [8].

Several studies have reported the zoonotic transmission of this pathogen from pigs, poultry, cattle, and other livestock to farm workers, and other exposed people [9,10,11]. A very recent study demonstrated the zoonotic transmission of MRSA from cattle to humans via environmental interfaces through the detection of MRSA in cattle, human and environmental samples in the same farm vicinity in Bangladesh [12]. In Cameroon, very few studies have investigated MRSA in cases of bovine mastitis [13] and the livestock environment [3]. This study aimed to examine the level of MRSA contamination in dairy cow’s mastitic milk and investigate the antimicrobial susceptibility of MRSA and the presence of some virulence factors, in order to understand the public health implications of consuming unpasteurized raw milk in the study area.

Materials and methods

Study area and data collection

The study was carried out in North West Cameroon, one of the most important cattle and milk production areas in the country [14]. The farms (with herd sizes ranging from 47 to 93), located at least 5 km from one another, were selected based on accessibility and farmers’ willingness to participate. The selected farms represented the typical local dairy production practices for commercial purposes in the study area. Quarter milk samples were collected only from lactating cows with mastitis in at least one teat (12–24 in each farm) that had not received antibiotics within the past 15 days, in order to increase the chances of recovering S. aureus. Ancillary data (including age, breed, herd size, husbandry system, and consumption of raw milk) were also recorded for each cow. A trained veterinarian examined each cow for signs of clinical mastitis while subclinical mastitis was confirmed using the California mastitis test (ImmuCell1 CMT, Portland, USA).

We calculated the sample size using Thrusfield’s formula of N = \(\:\frac{{Z}^{2}\times\:P\left(1-P\right)}{{d}^{2}}\) [15],

Where N = minimum sample size required, Z = 1.96 at a 95% confidence interval, P = expected prevalence of 11.1% of S. aureus contamination of milk and meat samples from a previous study in Cameroon [13] and d = desired absolute precision of 5%. This gave a sample size of 150, which was doubled in this study to increase precision [16].

Milk sample collection

Using aseptic techniques, the veterinarian collected ≈ 10mL quarter milk from the teat into a labelled screw-capped sterile plastic tube. The samples were transported on ice (4–8 °C) and stored at -20 °C in the Laboratory for Emerging Infectious Diseases, University of Buea, until needed for analysis.

Isolation and confirmation of Staphylococcus aureus

For isolation of S. aureus, 20µL of each sample were aseptically streaked on 5% sheep blood agar (Oxoid, Hampshire, England) and plates incubated aerobically at 37 °C for 24-48 h. Presumptive S. aureus colonies were purified on nutrient agar (Oxoid, Hampshire, England) followed by Gram staining, testing for catalase and coagulase production and phenotypic confirmation with API ID 20 STAPH gallery (bio-Merieux, France). For molecular confirmation of S. aureus, the nuc gene was amplified by PCR using primers previously described (Table 1). Unless otherwise stated, each PCR amplification was carried out in a 25µL final volume containing 5µL of DNA sample, 12.5µL of PCR mastermix (BioMix Red), 0.5µL of each primer (0.2µM), and nuclease-free water. A negative control (nuclease-free water replaced the DNA template) and a positive control (a previously identified S. aureus isolate stored in the laboratory [3] were included in each PCR run carried out in MyCycler™ Thermal Cycler (Bio-Rad, Hercules, CA, USA). The PCR cycling conditions for the nuc gene were 94 °C/5min, 40x [94 °C/1min, 58 °C/1min 72 °C/1min] and 72 °C/5min. Amplicons were electrophoresed on 1.5% high-resolution agarose gel stained with SYBR Safe DNA gel stain (Invitrogen). The amplified bands were visualized under ultraviolet light and photographed using Gel Documentation-XR (Bio-Rad, Hercules, CA, USA). Confirmed isolates were stored in nutrient broth supplemented with 20% glycerol at -70oC for downstream assays.

Table 1 Primers used in the study, sequences and expected amplicon sizes
Full size table

Phenotypic identification and genotypic confirmation of MRSA

Using cefoxitin (30 µg) discs, the S. aureus isolates were screened to identify MRSA following the Clinical and Laboratory Standards Institute (CLSI) guidelines [21], MRSA strains were selected from the S. aureus isolates. The amplification of the mecA gene (see primers in Table 1) was confirmatory for MRSA and the PCR cycling conditions were the same as described above.

Antimicrobial susceptibility testing of MRSA

The Kirby-Bauer disc diffusion method was used to determine susceptibility and resistance to the following antimicrobials (Oxoid, England): vancomycin (VA, 30 µg), tetracycline (TET, 30 µg), penicillin (P, 10IU), ampicillin (AMP, 10 µg), streptomycin (STR, 10 µg), gentamicin (CN, 10 µg), erythromycin (E, 15 µg), trimethoprim (TMP, 5 µg) and ciprofloxacin (CIP, 5 µg). Each inoculum, adjusted to 0.5 McFarland standard, was seeded on Mueller-Hinton agar (HiMedia Laboratories, India); the antibiotics discs were placed on the plate and incubated at 35 °C for 16-18 h. For each isolate that showed resistance to vancomycin, the minimum inhibitory concentration (MIC) was determined using the agar dilution method. The antimicrobial susceptibility assays were repeated thrice as a quality control measure. Results were interpreted according to breakpoints provided by CLSI [21]. Antimicrobials were selected to represent different antimicrobial classes and also comprised those commonly used to treat staphylococcal infections in human and veterinary medicine.

Screening MRSA for some virulence factors

The ability of these isolates to produce hydrolytic enzymes was determined by inoculating TSA-1 medium (Bio-Rad, USA) supplemented with: 1% skim milk for caseinase, 1% gelatin for gelatinase, Tween 80 for lipase and 5% egg yolk for lecithinase. The presence of the hydrolytic enzyme was confirmed by a clear halo around the colonies. Growth on 5% sheep blood agar was used to detect haemolytic activity [22, 23].

Four genes; coa [18], spa [19], tst and etb [20] were investigated in the MRSA strains in uniplex PCR reactions. Primers used for the amplification of these genes are listed in Table 1. The coa and spa genes were amplified under the same conditions as the nuc gene described above except for the annealing step set at 51 °C/1min and 50 °C/1min for the spa and coa genes respectively. Amplification conditions for the etb gene were 94 °C/5min, 40x [94 °C/40s, 55 °C/40s, 72 °C/40s] and 72 °C/7min. The PCR conditions for the tst gene were: 94 °C/5min, 40x [94 °C/2min, 54 °C/2min, 72 °C/2min] and 72 °C/5min.

Ethical considerations

North West Regional Delegation of Livestock, Fisheries and Animal Industries approved the use of animals in the study. Oral consent was obtained from the dairy farmers.

Statistical analysis

Epi info version 2000 (Centers for Disease Control and Prevention, Atlanta, Ga.) was used for statistical analysis. Chi-square (χ2) was applied to test whether associations between the distribution of MRSA and the possession of virulence genes were significant at p-value ≤ 0.05.

Results

Overall, 300 samples were collected from 112 dairy cows in six farms. The same husbandry system, semi-intensive, was used in rearing these cows. The consumption of raw unpasteurized milk was reported in all farms, and the leftovers of the milk were sold to the neighbouring communities. Although in some cases, S. aureus was isolated from more than one quarter milk sample of the same cow, each MRSA strain was isolated from a different cow.

A total of 201 (67%) S. aureus isolates were recovered from the 300 samples analysed in this study. Overall, 69 MRSA from all farms, were confirmed based on the possession of the mecA gene. MRSA contamination was recorded from both clinical and subclinical cases of mastitis (Table 2).

Table 2 The number of milk samples contaminated with MRSA from cows with clinical and subclinical mastitis
Full size table

All MRSA were resistant to ampicillin and penicillin followed by trimethoprim (69.6%) and tetracycline (69.6%). All isolates were susceptible to gentamicin followed by vancomycin (95.7%) and ciprofloxacin (91.3%) (Table 3).

Table 3 Antimicrobials and their susceptibility testing results for MRSA identified in this study
Full size table

Antibiotypes of MRSA circulating in dairy farms included in this study

A total of 13 antibiotypes, designated A1-A13 (Table 4), were identified. The antibiotypes A1, A6 and A8 were identified in all farms while the other antibiotypes were present only in some of the farms.

Table 4 Antibiotypes of MRSA identified in this study
Full size table

Possession of virulence factors by MRSA

Phenotypic virulence factor analysis revealed that all the MRSA were hemolytic; 27 isolates (39.1%) were β-hemolytic and 42 isolates (60.9%) were α-hemolytic. All isolates produced caseinase and coagulase. The majority of the MRSA produced lipase (97.1%), gelatinase (94.2%) and lecithinase (91.3%). Genotyping of the MRSA isolates revealed that all MRSA possessed the coa gene, followed by 47 (68.1%) for spa gene and none for the tst and etb genes. There was no statistically significant difference between the possession of virulence factors for MRSA strains from subclinical and clinical mastitis for the spa gene (p = 0.973), gelatinase (p = 0.818), and lecithinase (p = 0.739).

Discussion

Although milk from cows with clinical mastitis is not expected to be consumed because of its poor quality, the risk of zoonotic transmission is very high for the farmers handling the cows. The presence of MRSA in subclinical mastitis is a major public health concern, especially with the highly prevalent practice of consuming unpasteurized raw milk in the study area [13]. Staphylococcus aureus is one of the most common causes of animal disease in dairy farms and a major foodborne pathogen in humans. The contamination of milk with MRSA could be caused by the direct transfer of the bacterial pathogen through mastitis infection of the udder, unhygienic milking process, or contaminated farm environment [24]. The frequent use of antimicrobial agents to treat mammary infections in dairy cows is a risk factor for the emergence of antimicrobial resistance. Milk contaminated with MRSA could be a vehicle for the transmission of zoonotic pathogens to humans, thereby posing a serious threat to public health [25]. This study is very significant because the data presented here could be used to conduct evidence-based community outreach for awareness and training of dairy farmers, milk handlers and consumers to foster the implementation of hygiene practices in the farms. One of the biggest public health concerns is the potential spread of infectious agents to humans via unpasteurized milk consumption [24].

The contamination of milk with MRSA was recorded in both clinical and subclinical cases of bovine mastitis (24.2% and 20.4%, respectively) in this study. Previous studies in Korea reported lower levels of contamination of mastitic milk with MRSA of 4.3% [26], 13.9% [27] and 2.5% in Southern Italy [28]. While this study reported 67% (201/300) contamination of milk with S. aureus from mastitis milk, a recent study also in North West Cameroon reported 48.7% (19/39) [13] from milk regardless of mastitis status. Milk is often contaminated by Staphylococcus aureus commonly found on dairy cows [29]. Methicillin-resistant Staphylococcus aureus can originate from milk collected from the udder and its spread can be exacerbated by poor sanitation management and contaminated hands of farmers during the milking process [30]. Numerous previous studies have reported different rates of MRSA prevalence on dairy cattle farms in different regions [12, 31, 32]. The variations might be associated with different isolation procedures, sample sizes, sample sources, farm management systems, and other factors [33]. Several studies have reported the presence of MRSA in dairy cattle farms, farm workers, and raw milk, indicating the possible risk of MRSA transmission within and between dairy cattle farms and to the general public [28, 34, 35]. In a recent review that highlighted the role of milk products and milk in the spread of MRSA in the dairy production chain, higher contamination levels were reported for Africa than for Europe and Asia [24]. A recent study by Roy et al. [12] demonstrated a high similarity index (> 84%) among MRSA from cows, humans and the environmental surfaces within the same farm vicinity to highlight the zoonotic potential of MRSA and the importance of MRSA control using the ‘One Health’ approach.

All the MRSA in this study were resistant to penicillin and ampicillin, and this corroborates a previous study that investigated penicillin resistance of staphylococcal isolates from subclinical mastitis in Sohag City, Egypt [36] and another study on raw milk samples from a rural community in Edo State, Nigeria [37]. While susceptibility to gentamicin for MRSA in the present study was 100%, Yang et al. [38] reported that all 73 MRSA were resistant to gentamicin in their study that investigated MRSA from subclinical mastitis in China. An earlier study in Pakistan reported that 10% of the 135 MRSA isolates identified were resistant to gentamicin [39]. We also observed high susceptibility to ciprofloxacin (91.3%). Although this study reported only a 4.3% resistance to vancomycin, a previous study in Cameroon reported high (80%) resistance to vancomycin [13]. This wide difference in the resistance rates for isolates from the same country may be because the isolates come from different regions, and the cattle are reared under different husbandry practices. The emergence of resistance to vancomycin is a feared genetic adaptation in S. aureus so far, due to the widespread reliance on this antibiotic for treating MRSA infections in humans [40]. Most isolates (65.2%, 45/69) were multidrug-resistant and this represents a major public health challenge because MRSA carrying antibiotic resistance genes can horizontally transfer these determinants between strains, resulting in pathogen evolution [41].

In this study, we noted that all isolates were α- or β-haemolytic. This finding corroborates the results of Barretti et al. [42]. Αlpha-haemolysin has pro-inflammatory and pore-forming properties. It can disrupt the integrity of host cells when it binds to a membrane receptor [43]. Lipase, protease, and lecithinase secretion were detected in most tested strains and this corroborates results from most previous studies [42, 44, 45]. Staphylococcus aureus uses lipolytic and proteolytic exoenzymes for host tissue invasion, causing damage to the host tissue components and even spreading to other sites [18]. Our isolates lacked the tst or etb genes and this result corroborates previous studies [46]. The prevalence of the tst and etb genes from S. aureus in cases of bovine mastitis was generally low [46]. However, the study of Zschöck et al. [47] showed a 36.2% prevalence of the tst gene in S. aureus isolates while that of Teyhoo et al. [48] showed a 14–20% prevalence rate.

Conclusion

This study revealed 23.0% milk contamination with MRSA in the study area. Multidrug resistance was identified in 65.2% of the MRSA isolates, while several isolates possessed virulence factors that can lead to the severity of infection in humans. The presence of resistance and virulence genes suggests a serious risk for transmission to humans through contaminated milk, highlighting the need for better farm hygiene, careful antibiotic use to reduce public health threats and the need for further studies to confirm transmission pathways. We recommend education of herders on measures to minimize contamination and monitoring of multidrug-resistant bacteria in milk and dairy products to prevent the transmission of MRSA from animals to humans.

Limitations

This study did not investigate risk factors associated with MRSA contamination or antimicrobial use in cattle farms. This information is also critical in monitoring and controlling MRSA spread in cattle farms and the local population. Another limitation is that only the MecA gene was used to confirm MRSA. Thus the MRSA contamination prevalence reported in this study might be an underestimation. Previous studies have reported that there are alternative gene targets specific to MRSA such as the blaZ [49] and the new MecA homologue MecA(LGA251) [50]. Although the data reported here are very pertinent, this is a small-scale study and the findings might not be generalizable to other regions of the country and elsewhere. From the findings reported in this study, we are not able to know if the MRSA strains circulating in the farms are epidemiologically distinct. We, therefore, recommend further studies to identify the MRSA clones circulating in the study area.

Data availability

All data is provided within the manuscript.

References

  1. Ayele Y, Gutema FD, Edao BM, Girma R, Tufa TB, Beyene TJ, et al. Assessment of Staphylococcus aureus along milk value chain and its public health importance in Sebeta, central Oromia, Ethiopia. BMC Microbiol. 2017;17(1):141.

    Article  PubMed  PubMed Central  Google Scholar 

  2. Nhatsave N, Garrine M, Messa A Jr, Massinga AJ, Cossa A, Vaz R, et al. Molecular characterization of Staphylococcus aureus isolated from raw milk samples of dairy cows in Manhiça District, Southern Mozambique. Microorganisms. 2021;9(8):1684.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Esemu SN, Yaya FA, Nkengum WP, Kaah Keneh N, Kfusi JA, Smith SI, et al. Prevalence and characterization of methicillin-resistant Staphylococcus aureus from meat retail shops and meat handlers in the Buea municipality, Cameroon. Int J Trop Disease Health. 2021;42(21):13–27.

    Article  Google Scholar 

  4. Dai J, Wu S, Huang J, Wu Q, Zhang F, Zhang J, et al. Prevalence and characterization of Staphylococcus aureus isolated from pasteurized milk in China. Front Microbiol. 2019;10:641.

    Article  PubMed  PubMed Central  Google Scholar 

  5. Schnitt A, Tenhagen BA. Risk factors for the occurrence of methicillin-resistant Staphylococcus aureus in dairy herds: an update. Foodborne Pathog Dis. 2020;17(10):585–96.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Kavanagh KT. Control of MSSA and MRSA in the United States: protocols, policies, risk adjustment and excuses. Antimicrob Resist Infect Control. 2019;8:103.

    Article  PubMed  PubMed Central  Google Scholar 

  7. Silva V, Monteiro A, Pereira JE, Maltez L, Igrejas G, Poeta P. MRSA in humans, pets and livestock in Portugal: where we came from and where we are going. Pathogens. 2022;11:1110.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Shoaib M, Aqib AI, Muzammil I, Majeed N, Bhutta ZA, Kulyar MF, et al. MRSA compendium of epidemiology, transmission, pathophysiology, treatment, and prevention within one health framework. Front Microbiol. 2022;13:1067284.

    Article  PubMed  Google Scholar 

  9. Armand-Lefevre L, Ruimy R, Andremont A. Clonal comparison of Staphylococcus aureus isolates from healthy pig farmers, human controls, and pigs. Emerg Infect Dis. 2005;11:711–4.

    Article  PubMed  PubMed Central  Google Scholar 

  10. Nemati M, Hermans K, Lipinska U, Denis O, Deplano A, Struelens M, et al. Antimicrobial resistance of old and recent Staphylococcus aureus isolates from poultry: first detection of livestock-associated methicillin-resistant strain ST398. Antimicrob Agents Chemother. 2008;52:3817–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Graveland H, Wagenaar JA, Heesterbeek H, Mevius D, van Duijkeren E, Heederik D. Methicillin-resistant Staphylococcus aureus ST398 in veal calf farming: human MRSA carriage related with animal antimicrobial usage and farm hygiene. PLoS ONE. 2010;5:e10990.

    Article  PubMed  PubMed Central  Google Scholar 

  12. Roy MC, Chowdhury T, Hossain MT, Hasan MM, Zahran E, Rahman MM, Zinnah KMA, Rahman MM, Hossain FMA. Zoonotic linkage and environmental contamination of Methicillin-resistant Staphylococcus aureus (MRSA) in dairy farms: a one health perspective. One Health. 2024;18:100680. https://doi.org/10.1016/j.onehlt.2024.100680. PMID: 39010963; PMCID: PMC11247269.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Bissong MEA, Tahnteng BF, Ateba CN, Akoachere JTK. Pathogenic potential and antimicrobial resistance profile of Staphylococcus aureus in milk and beef from the Northwest and Southwest Regions of Cameroon. Biomed Research International. 2020; 2020: 6015283.

  14. Abegewi UA, Esemu SN, Ndip RN, Ndip LM. Prevalence and risk factors of coliform-associated mastitis and antibiotic resistance of coliforms from lactating dairy cows in North West Cameroon. PLoS ONE. 2022;17(7):e0268247.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Thrusfield M. Veterinary epidemiology. England: Wiley; 2018.

    Book  Google Scholar 

  16. Dohoo IR, Martin W, Stryhn HE. Veterinary Epidemiologic Research, 2003, 2nd edition, Ver Inc.charlottetown.Prince Edward Island, Charlottetown, Canada.

  17. Wilson IG, Cooper JE, Gilmour A. Detection of enterotoxigenic Staphylococcus aureus in dried skimmed milk: use of the polymerase chain reaction for amplification and detection of staphylococcal enterotoxin genes entB and entC1 and the thermonuclease gene nuc. Appl Environ Microbiol. 1991;57(6):1793–8.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Enany M, Younes S, AL gammal AE, Salem M, El Dieb H. Prevalence of coagulase (coa) gene and mecA gene of S. Aureus isolated from bovine clinical mastitis. Suez Canal Veterinary Med J. 2013;18:149–57.

    Article  Google Scholar 

  19. Votintseva AA, Fung R, Miller RR, Knox K, Godwin H, Wyllie DH, et al. Prevalence of Staphylococcus aureus protein A (spa) mutants in the community and hospitals in Oxfordshire. BMC Microbiol. 2014;14:63.

    Article  PubMed  PubMed Central  Google Scholar 

  20. Mehrotra M, Wang G, Johnson WM. Multiplex PCR for detection of genes for Staphylococcus aureus enterotoxins, exfoliative toxins, toxic shock syndrome toxin 1, and methicillin resistance. J Clin Microbiol. 2000;38(3):1032–5.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. CLSI. Performance standards for antimicrobial susceptibility testing, 33rd Edition. 2023; M100.

  22. Haddad O, Merghni A, Elargoubi A, Rhim H, Kadri Y, Mastouri M. Comparative study of virulence factors among methicillin resistant Staphylococcus aureus clinical isolates. BMC Infect Dis. 2018;18(1):560. https://doi.org/10.1186/s12879-018-3457-2. PMID: 30424731; PMCID: PMC6234561.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Stulik L, Malafa S, Hudcova J, Rouha H, Henics BZ, Craven DE, et al. αHemolysin activity of methicillin-susceptible Staphylococcus aureus predicts ventilator-associated pneumonia. Am J Respir Crit Care Med. 2014;15:113948. https://doi.org/10.1164/rccm.201406-1012OC.

    Article  CAS  Google Scholar 

  24. Titouche Y, Akkou M, Houali K, Auvray F, Hennekinne JA. Role of milk and milk products in the spread of methicillin-resistant Staphylococcus aureus in the dairy production chain. J Food Sci. 2022;87(9):3699–723.

    Article  CAS  PubMed  Google Scholar 

  25. Esemu SN, Njoh ST, Ndip LM, Keneh NK, Kfusi JA, Njukeng AP. Ready-to-eat foods: A potential vehicle for the spread of coagulase-positive staphylococci and antimicrobial-resistant Staphylococcus aureus in Buea municipality, South West Cameroon. Canadian Journal of Infectious Diseases and Medical Microbiology. 2023; 2023: Article ID 9735319.

  26. Nam HM, Lee AL, Jung SC, Kim MN, Jang GC, Wee SH, et al. Antimicrobial susceptibility of Staphylococcus aureus and characterization of methicillin-resistant Staphylococcus aureus isolated from bovine mastitis in Korea. Foodborne Pathog Dis. 2011;8(2):231–8.

    Article  CAS  PubMed  Google Scholar 

  27. Song JW, Yang SJ, Shin S, Seo KS, Park YH, Park KT. Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus isolated from bovine mastitic milk in Korea. J Food Prot. 2016;79:1725–32.

    Article  CAS  PubMed  Google Scholar 

  28. Parisi A, Caruso M, Normanno G, Latorre L, Sottili R, Miccolupo A, et al. Prevalence, antimicrobial susceptibility and molecular typing of Methicillin-Resistant Staphylococcus aureus (MRSA) in bulk tank milk from southern Italy. Food Microbiol. 2016;58:36–42.

    Article  CAS  PubMed  Google Scholar 

  29. Gebremedhin EZ, Ararso AB, Borana BM, Kelbesa KA, Tadese ND, Marami LM, Sarba EJ. Isolation and identification of Staphylococcus aureus from milk and milk products, Associated Factors for Contamination, and their Antibiogram in Holeta, Central Ethiopia. Vet Med Int. 2022;2022:6544705. https://doi.org/10.1155/2022/6544705. PMID: 35574151; PMCID: PMC9106507.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Rafif Khairullah A, Rehman S, Agus Sudjarwo S, Helmi Effendi M, Chasyer Ramandinianto S, Aega Gololodo M, et al. Detection of mecA gene and methicillin-resistant Staphylococcus aureus (MRSA) isolated from milk and risk factors from farms in Probolinggo. Indonesia F1000Res. 2022;11:722.

    Article  PubMed  Google Scholar 

  31. González-Machado C, Capita R, Alonso-Calleja C. Methicillin-resistant Staphylococcus aureus (MRSA) in dairy products and bulk-tank milk (BTM). Antibiotics. 2024;13(7):588.

    Article  PubMed  PubMed Central  Google Scholar 

  32. Khasapane NG, Koos M, Nkhebenyane SJ, Khumalo ZT, Ramatla T, Thekisoe O. Detection of staphylococcus isolates and their antimicrobial resistance profiles and virulence genes from subclinical mastitis cattle milk using MALDI-TOF MS, PCR and sequencing in free state province, South Africa. Animals. 2024;14(1):154.

    Article  PubMed  PubMed Central  Google Scholar 

  33. Girmay W, Gugsa G, Taddele H, Tsegaye Y, Awol N, Ahmed M et al. Isolation and identification of methicillin-resistant Staphylococcus aureus (MRSA) from milk in shire dairy farms, Tigray, Ethiopia. Veterinary Medicine International. 2020; 2020: 8833973.

  34. Giovanni N, Elisa S, Marta C, Rosa F, Loredana C, Alessandra B, et al. Occurrence and characteristics of methicillin-resistant Staphylococcus aureus (MRSA) in buffalo bulk tank milk and the farm workers in Italy. Food Microbiol. 2020;91:103509.

    Article  CAS  PubMed  Google Scholar 

  35. Papadopoulos P, Angelidis AS, Papadopoulos T, Kotzamanidis C, Zdragas A, Papa A et al. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in bulk tank milk, livestock and dairy-farm personnel in north-central and north-eastern Greece: prevalence, characterization and genetic relatedness. Food Microbiology. 2019; 84: 103249.

  36. Abd-Al-Azeem MW, Shaheen HM, Abdel-Hameed KG, Helmy MM. Penicillin resistance against Staphylococcal isolates recovered from subclinical mastitis in Sohag City, Egypt. American J Res Com. 2013;1:116–30.

    Google Scholar 

  37. Igbinosa EO, Beshiru A, Akporehe LU, Ogofure AG. Detection of methicillin-resistant staphylococci isolated from food producing animals: a public health implication. Veterinary Sci. 2016;3(3):14.

    Google Scholar 

  38. Yang F, Zhang S, Shang X, Li H, Zhang H, Cui D, et al. Short communication: detection and molecular characterization of methicillin-resistant Staphylococcus aureus isolated from subclinical bovine mastitis cases in China. J Dairy Sci. 2020;103(1):840–5.

    Article  CAS  PubMed  Google Scholar 

  39. Aqib AI, Ijaz M, Anjum AA, Malik MAR, Mehmood K, Farooqi SH, Hussain K. Antibiotic susceptibilities and prevalence of Methicillin resistant Staphylococcus aureus (MRSA) isolated from bovine milk in Pakistan. Acta Trop. 2017;176:168–72. Epub 2017 Aug 7. PMID: 28797802.

    Article  CAS  PubMed  Google Scholar 

  40. Turner NA, Sharma-Kuinkel BK, Maskarinec SA, Eichenberger EM, Shah PP, Carugati M, et al. Methicillin-resistant Staphylococcus aureus: an overview of basic and clinical research. Nat Rev Microbiol. 2019;17(4):203–18.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Mashouf RY, Hosseini SM, Mousavi SM, Arabestani MR. Prevalence of enterotoxin genes and antibacterial susceptibility pattern of Staphylococcus aureus strains isolated from animal originated foods in West of Iran. Oman Med J. 2015;30(4):283–90.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. Barretti P, Montelli AC, Batalha JE, Caramori JC, Cunha Mde L. The role of virulence factors in the outcome of staphylococcal peritonitis in CAPD patients. BMC Infect Dis 2009; 9 (212).

  43. Inoshima N, Wang Y, Wardenburg JB. Genetic requirement for ADAM10 in severe Staphylococcus aureus skin infection. J Invest Dermatology. 2012;132:1513–6.

    Article  CAS  Google Scholar 

  44. Wu PZ, Zhu H, Thakur A, Willcox MD. Comparison of potential pathogenic traits of staphylococci that may contribute to corneal ulceration and inflammation. Aust N Z J Ophthalmol. 1999;27:234–6.

    Article  CAS  PubMed  Google Scholar 

  45. Lakshmi HP, Prasad UV, Yeswanth S, Swarupa V, Prasad OH, Narasu ML, et al. Molecular characterization of α-amylase from Staphylococcus aureus. Bioinformation. 2013;9:281–5.

  46. Sauer P, Síla J, Štosová T, Večeřová R, Hejnar P, Vágnerová I, et al. Prevalence of genes encoding extracellular virulence factors among meticillin-resistant Staphylococcus aureus isolates from the University Hospital, Olomouc, Czech Republic. J Med Microbiol. 2008;57(4):403–10.

    Article  CAS  PubMed  Google Scholar 

  47. Mohseni M, Rafiei F, Ghaemi EA. High frequency of exfoliative toxin genes among Staphylococcus aureus isolated from clinical specimens in the north of Iran: alarm for the health of individuals under risk. Iran J Microbiol. 2018;10(3):158–65.

    PubMed  PubMed Central  Google Scholar 

  48. Zschöck M, Botzler D, Blöcher S, Sommerhäuser J, Hamann HP. Detection of genes for enterotoxins (ent) and toxic shock syndrome toxin-1 (tst) in mammary isolates of Staphylococcus aureus by polymerase-chain-reaction. Int Dairy J. 2000;10(8):569–74.

    Article  Google Scholar 

  49. Martineau F, Picard FJ, Lansac N, Ménard C, Roy PH, Ouellette M, Bergeron MG. Correlation between the resistance genotype determined by multiplex PCR assays and the antibiotic susceptibility patterns of Staphylococcus aureus and Staphylococcus epidermidis. Antimicrob Agents Chemother. 2000;44(2):231–8. PMID: 10639342; PMCID: PMC89663.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Stegger M, Andersen PS, Kearns A, Pichon B, Holmes MA, Edwards G, Laurent F, Teale C, Skov R, Larsen AR. Rapid detection, differentiation and typing of methicillin-resistant Staphylococcus aureus harbouring either mecA or the new mecA homologue mecA(LGA251). Clin Microbiol Infect. 2012;18(4):395–400. https://doi.org/10.1111/j.1469-0691.2011.03715.x. PMID: 22429460.

Download references

Acknowledgements

The authors are grateful to the staff of MINEPIA, North West Region, Cameroon, for assistance in sample collection.

Funding

Partial support was obtained from the South African Medical Research Council through an award to POB. The views expressed here are those of the authors and not necessarily of their affiliated institutions.

Author information

Authors and Affiliations

  1. Department of Microbiology and Parasitology, Faculty of Science, University of Buea, Box 63, Buea, Cameroon

    Seraphine Nkie Esemu, Shantal Fuenbi Nya’Nying, Lucy Mande Ndip & Roland Ndip Ndip

  2. Laboratory for Emerging Infectious Diseases, University of Buea, Box 63, Buea, Cameroon

    Seraphine Nkie Esemu, Lucy Mande Ndip & Roland Ndip Ndip

  3. South African Medical Research Council - University of Venda Antimicrobial Resistance and Global Health Research Unit, Thohoyandou, 0950, South Africa

    Pascal Obong Bessong

  4. Center for Global Health Equity, University of Virginia, Charlottesville, USA

    Pascal Obong Bessong

  5. Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Box 63, Buea, Cameroon

    Nicoline Fri Tanih

  6. Department of Molecular Biology and Biotechnology, Nigerian Institute of Medical Research, Lagos, Nigeria

    Stella Ifeanyi Smith

Authors
  1. Seraphine Nkie Esemu
    View author publications

    Search author on:PubMed Google Scholar

  2. Shantal Fuenbi Nya’Nying
    View author publications

    Search author on:PubMed Google Scholar

  3. Lucy Mande Ndip
    View author publications

    Search author on:PubMed Google Scholar

  4. Pascal Obong Bessong
    View author publications

    Search author on:PubMed Google Scholar

  5. Nicoline Fri Tanih
    View author publications

    Search author on:PubMed Google Scholar

  6. Stella Ifeanyi Smith
    View author publications

    Search author on:PubMed Google Scholar

  7. Roland Ndip Ndip
    View author publications

    Search author on:PubMed Google Scholar

Contributions

SNE: Data curation, investigation, original draft preparation, review and editing; SFN: Sample collection and investigation, review and editing; LMN: Conceptualization, supervision, resources, review and editing; POB: Conceptualization and resources; NFT: Data curation, review and editing; SIS: Conceptualization, review and editing; RNN: Conceptualization, supervision, resources, data validation, review and editing.

Corresponding author

Correspondence to Seraphine Nkie Esemu.

Ethics declarations

Ethical approval and consent to participate

This study was reviewed and approved (Ref. No. MINEPIA/DREPIA/NW/40/716/2019) by the Regional Delegation of Livestock, Fisheries and Animal Industries, a subunit of the country’s government institution that oversees livestock production and animal health for the North West Region of Cameroon. Collection of the milk samples was done after obtaining informed verbal consent from farm owners. All samples were collected by a trained veterinarian. No invasive procedures were involved, and very little pain was inflicted on the animals during the sample collection process. This study did not involve endangered or protected species and did not use animals for experiments.

Animal ethics declaration

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Esemu, S.N., Nya’Nying, S.F., Ndip, L.M. et al. Isolation and characterization of methicillin-resistant Staphylococcus aureus from bovine mastitis in North West Cameroon: public health implications. BMC Res Notes 17, 389 (2024). https://doi.org/10.1186/s13104-024-07073-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s13104-024-07073-3

Keywords

BMC Research Notes

ISSN: 1756-0500

Contact us