Evaluation of close up antimicrobial therapies for treatment and prevention of subclinical mastitis in the herds with high prevalence of Staphylococcus aureus.

This field trial was conducted to evaluate two antibiotics at a close-up period in curing the existing IMI and to prevent new clinical and subclinical Intramammary infection (IMI). Two hundred and twelve Holstein cows were assigned to one of three treatment groups: TYLO, MARB and CONT. Cows in TYLO group received 10 mg/kg Tylosin for three days at the close-up period (21 days before calving), cows in MARB group received single SC injection of 8 mg/kg SC marbofloxacin at the close-up period and cows in CONT group remained untreated. Milk samples were collected for somatic cell count, microbial culture and Total oxidant/antioxidant capacity before drying-off, and 3 and 7days post calving. Antimicrobial susceptibility test and RAPT-PCR were performed on S.aureus isolates. No significant differences were detected in total cure rate within the groups, but S. aureus cure rates in TYLO and MARB were significantly higher than in CONT (74 and 73.5 % Vs 58.1 %). No significant differences in total new IMI were observed. Furthermore, the rate of new S. aureus IMI was higher in both treatment groups than in CONT group. Clinical mastitis rate in TYLO (3.8 %) and MARB (5.8 %) was significantly lower than CONT (11.3 %). Paired S. aureus isolates from dry-off and post-calving have been clustered into 9 different RAPD types (A-I). 8 paired strains collected at dry-off were identical to those at post-calving,and 35 strains had more than 60 % dissimilarity. Administration of Tylosin or Marbofloxacin is not useful in all cases;however, they have the potential to reduce the incidence of post-calving clinical mastitis and improve S.aureus cure rate if used selectively.

Genotypic and phenotypic diversity of Prototheca spp. recovered from bovine mastitis in terms of antimicrobial resistance and biofilm formation ability.

BACKGROUND: The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Isolates from bovine mastitis in several countries were nearly all identified as P. bovis, suggesting that it was the main causative agent of bovine protothecal mastitis. The aim of the present study was to evaluate the presence and isolation of Prototheca spp. in dairy farms, detect the genetic diversity among strains, determine the capacity of producing biofilm and their resistance to antifungal and antimicrobial drugs. RESULTS: A total of 48 Prototheca isolates from four different farms were randomly selected to be investigated. Multiplex PCR showed all isolated colonies were Prototheca bovis. Performing RAPD-PCR by using OPA-4 primer, it was revealed that there was a clear amplification pattern. Different levels of biofilm production were observed among strains. Among 48 isolates, only 4 of them (8.33%) showed strong biofilm production. By using E-test strips, amphotericin B was able to inhibit the growth of all the strains tested. Disc diffusion method used for antimicrobial sensitivity test showed that the highest activity was demonstrated by gentamicin and colistin with 95.83% (46/48) and 89.58% (43/48) of sensitive strains, respectively. CONCLUSIONS: The present study showed that RAPD-PCR was a rapid tool for discriminating P. bovis strains. Also, gentamicin and colistin can be considered as potential antimicrobial drugs which can prevent the growth of the mentioned strains in vitro, although there is no effective clinical treatment yet. Further studies are needed in order to detect an effective clinical therapy considering biofilm production by Prototheca spp. and their probable role in Prototheca pathogenicity.

Isolation and evaluation of the efficacy of bacteriophages against multidrug-resistant (MDR), methicillin-resistant (MRSA) and biofilm-producing strains of Staphylococcus aureus recovered from bovine mastitis.

BACKGROUND: Staphylococcus aureus (S. aureus) is one of the major causes of bovine mastitis with significant economic losses around the worldwide. The emergence of multidrug-resistant (MDR), methicillin-resistant (MRSA) and biofilm-producing strains of S. aureus challenges the treatment strategies based on the antibiotic application. Today, alternative or combinational treatment options such as bacteriophage application has received much attention. The goal of the present study was to focus on isolation and evaluation of the efficacy of bacteriophages with specific lytic activity against S. aureus strains with low cure rates (MDR, MRSA and biofilm-producing strains). RESULTS: In the present study, two phages belonging to the Podoviridae family with specific lytic activity against S. aureus were isolated from the sewage of dairy farms and designated as Staphylococcus phage M8 and Staphylococcus phage B4. Latent period and burst size for Staphylococcus phage M8 (70 min, 72 PFU/cell) and Staphylococcus phage B4 (30 min, 447 PFU/cell) were also defined. Our results revealed the susceptibility of MDR (4/20; 20%), MRSA (4/13; 30.8%) and biofilm-producing (1/10; 10%) strains to Staphylococcus phage M8. Moreover, one biofilm-producing strain (1/10; 10%) was susceptible to Staphylococcus phage B4. Furthermore, both phages kept their lytic activity in milk. They reduced the S. aureus population by about 3 logs in cultured milk after 8 h of incubation. CONCLUSION: In conclusion, it seems that both phages had the potential to serve as biological control agents alone or in combination with other agents such as antibiotics against infections induced by S. aureus. However, further studies are needed to investigate the efficacy of these phages in vivo.

Comparison of the effects of tylosin and tilmicosin as a systemic treatment of dry Holstein cows.

The aim of the present study was to evaluate the efficacy of macrolides to eliminate intramammary infection (IMI) caused by Staphylococcus aureus (S. aureus) and Streptoccus spp. 3 weeks before calving time. Eighty Holstein dairy cows with subclinical mastitis pathogens were divided into three groups. Three weeks before expected parturition time, cows in group 1 received tilmicosin (n = 29), cows in group 2 received tylosin (n = 30) and cows in group 3 were left as negative control (n = 21). Milk samples were obtained on 3 and 7 days after calving. Randomly amplified polymorphic DNA (RAPD) method was determined for all of the S. aureus isolates that had the same isolates before and after parturition. The total cure rate was 63.33, 75.86 and 66.66% for tylosin, tilmicosin and control groups, respectively. Furthermore, cure rates were not significant, when each type of mastitis causing pathogens were considered separately. The incidence of clinical mastitis during 60 days after calving for tylosin, tilmicosin and Control groups was 23.33, 27.58 and 38.09%, respectively. Only four S. aureus isolated before drying-off were similar to post-calving isolate, according to RAPD-PCR method. In conclusion, antibiotic therapy before calving improved the cure rate numerically, however, it was not significant.

Milk metabolites, proteins and oxidative stress markers in dairy cows suffering from Staphylococcus aureus subclinical mastitis with or without spontaneous cure.

Our objective was to evaluate relationships between milk components (acute phase proteins, enzymes, metabolic parameters and oxidative indices) and the spontaneous cure outcome of Staphylococcus aureus subclinical mastitis in dairy cows. The values of haptoglobin, serum amyloid A (SAA), malondialdehyde (MDA), total antioxidant capacity, milk urea nitrogen (MUN), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), electrolytes (Cl and K), total protein, albumin, α-lactalbumin, ß-lactoglobulin, and immunoglobulin were measured in milk samples of S. aureus subclinical mastitis cows with spontaneous cure (n = 23), S. aureus subclinical mastitis cows without spontaneous cure (n = 29) and healthy cows (n = 23). The comparison of measured parameters revealed that subclinical mastitis cows with spontaneous cure had lower ALP and haptoglobin concentrations both at diagnosis and after cure (P < 0.05). In contrast, total antioxidant capacity and MDA concentration in subclinical mastitis cows without spontaneous cure significantly increased with time (P < 0.05). We can suggest that elevated haptoglobin concentration and higher ALP activity indicative of enhanced oxidative stress could potentially serve as early diagnostic indicators of chronic disease and the persistence of S. aureus subclinical mastitis in dairy cows.

Development of three multiplex-PCR assays for virulence profiling of different iron acquisition systems in Escherichia coli.

BACKGROUND AND OBJECTIVES: Escherichia coli is responsible for various enteric and extraintestinal infections in animals and humans. Iron as an essential nutrient, has a proven role in pathogenicity of E. coli. Pathogenic E. coli benefits of having complicated systems for iron acquisition but our current knowledge is limited because of complexity of these systems. In the present study, three multiplex-PCR assays were developed to screen nine different virulence genes related to diverse iron acquisition systems in E. coli. MATERIALS AND METHODS: The multiplex-PCR systems were designed and optimized in three panels. Each panel includes a triplex-PCR cocktail. The panels are as follow: panel 1: iroN, iutA and fecA; panel 2: fyuA, sitA and irp2; and panel 3: iucD, chuA and tonB. A total of 39 pathogenic E. coli was screened according to the designed multiplex-PCR. RESULTS: In total, the top three frequent genes were tonB (100%), fecA (66.6%) and sitA (58.9%). With the exception of fecA and tonB, comparing the prevalence of genes among different origin of isolates (human, cattle, poultry and pigeon) showed significant associations (P < 0.05). Moreover, the iroN, sitA and iucD genes were significantly prevalent (P < 0.05) among members of extraintestinal pathogenic E. coli in comparison with the group of diarrheagenic E. coli. CONCLUSION: The current multiplex-PCR assays could be a valuable, rapid and economic tool to investigate diverse iron acquisition systems in E. coli for more precise virulence typing of pathogenic or commensal strains.

Evaluating the effectiveness of two bovine mastitis vaccines and their influences on oxidant and antioxidant capacities of milk.

The aim of the current study was to investigate the efficacy of two commercial mastitis vaccines (Startvac® and Mastivac®) and their influence on oxidant and antioxidant capacities of milk samples in a dairy farm. A total of 165 Holstein dairy cows were recruited into the study and were divided into Startvac®, Mastivac®, and control groups. The effects on the incidence and severity of clinical mastitis cases, duration of treatment, infection status, bacteriologic culture, somatic cell count, 5-thio-2-nitrobenzoic acid assay and ferric reducing antioxidant power assay, incidence of metritis and endometritis, and milk yield were evaluated within the first 90 days of lactation. The incidence of clinical mastitis was not significantly different among groups. The mean SCCs during the first, second, and third months of lactation did not differ significantly. The percentage of cured cows did not differ significantly. TNB and FRAP assays were used to know whether or not vaccination against mastitis has an effect on oxidant and antioxidant capacity of milk samples, which did not differ significantly. In conclusion, we observed no significant difference in the abovementioned variables. However, it is possible that applying mastitis vaccines within the specific conditions may have positive effects considering the results of previous studies.

Phenotypic and genotypic study on antimicrobial resistance patterns of E. coli isolates from bovine mastitis.

It is important to evaluate the antimicrobial resistance pattern by genotypic and phenotypic methods in epidemiological studies in order to control antimicrobial resistance and to improve the outcome of the treatments. Four-hundred and thirty clinical mastitis samples were collected from 14 dairy herds in five different cities. The antimicrobial susceptibility test was performed using agar disk diffusion for 70 identified Escherichia coli isolates. The antimicrobial resistance genes including strA, strB, aadA, sulI, sulII, sulIII, ampC were detected by PCR method. Phylogenic groups were determined by Clermont's multiplex PCR method, and RAPD typing was performed on all isolates. Most isolates were resistant to lincomicin and streptomycin, whereas sulfa-trimethoprim has the lowest resistance rate. Moreover, ampC, aadA and sul2 genes had the highest frequency (92.85%, 38.57%, and 32.85% respectively). 20% of all the isolates carried strA and strB genes, and 11.42% of the isolates had sul1 gene and 10% of the isolates had the less frequent sul3 gene. Of the total of 70 E. coli isolates, 26 (37.14%), 20 (28.5%), 17 (24.2%), 8 (11.4%) isolates belonged to B1, A, B2 and D phylogenic groups respectively. strA, strB, sul2and aadA resistance genes had the highest percentage in A phylogenic groups. Based on RAPD-PCR method, E. coli isolates were classified in four clusters. The result showed a high phenotypic and genotypic E. coli resistance to the current antimicrobials with a similar pattern in different cities; also the majority of E. coli isolates belonged to B1 group which mainly contains the commensal E. coli isolates.

A high prevalence of tylosin resistance among Staphylococcus aureus strains isolated from bovine mastitis.

The macrolides appear to have considerable effects for treatment of bovine mastitis because of excellent diffusion into the mammary gland, long half-life, low protein binding, high intracellular concentration and lipid solubility. Acquired resistance to macrolides in Staphylococcus aureus is primarily related to target-site modification through acquisition of an erm gene. In the present study the prevalence of both phenotypic and genotypic tylosin resistance in S. aureus isolates (n = 103) from subclinical mastitis in nine dairy farms belonging to three different province of Iran were investigated. Overall, ermA, ermB and ermC was found in 7.80%, 32.00%, and 20.40% of S.aureus isolates, respectively. A very high percent of isolates (56.90%) were resistant to tylosin. MIC90 and MIC50 values were 64 and 32 µg mL-1, respectively. Most of tylosin resistant isolates did not harbour any erm gene but ermB was dominant gene among 58 tylosin resistant isolates of S. aureus. In overall, tylosin resistance was prevalent in S. aureus isolates obtained from bovine mastitis in Iran.

Comparison of virulence factors and capsular types of Streptococcus agalactiae isolated from human and bovine infections.

Streptococcus agalactiae is a leading cause of human and bovine infections. A total of 194 S. agalactiae isolates, 55 isolates from bovines and 139 from humans, were analyzed for capsular types, virulence genes (scpB, hly, rib, bca and bac) and mobile genetic elements (IS1548 and GBSi1) using polymerase chain reaction (PCR) and multiplex PCR. Capsular type III was predominant (61%), followed by types V, II, Ib, and IV. The scpB, hly, bca and bac virulence genes were only found among human isolates. Twelve and 2 distinct virulence gene profiles were identified among human and bovine isolates respectively. The virulence gene profiles scpB- hly- IS1548- rib-bca (51%) and scpB- hly- IS1548- bca (19%) were only predominant among human isolates. The rib gene was the most common virulence gene in both human and bovine isolates. The study showed a high prevalence of virulence genes in S. agalactiae strains isolated from human infections, these result can support the idea that S. agalactiae isolated from humans and bovines are generally unrelated and probably belonged to separate populations.

Comparison of virulence factors and biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections.

The aim of this study was to find different prevalence of genes involved in the biofilm formation process and to assess the phenotypic and genotypic markers of biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections. In this study, 215 S. aureus strains were collected from human and dairy cow's infections. The biofilm forming capacity of the strains was evaluated using a colorimetric microtiter plate assay. The genes encoding microbial surface components, recognizing adhesive matrix molecules (MSCRAMMs) (ebpS, eno, fib, fnbA, fnbB, cna and bap), and the intracellular adhesion (ica) genes (icaA, and icaD) were targeted by polymerase chain reaction (PCR)-based method. Approximately 70% of the isolates produced biofilm. Among these, 59.3% were producers of weakly adherent biofilms while 34.8% and 5.8% produced moderate and strong biofilms, respectively. The most prevalent gene was icaD found in 88.4% of the isolates, followed by icaA, fib and eno found in 87.9%, 75.8% and 75.3% of the isolates, respectively. The bap gene was not detected in any of the isolates. The prevalence of ebpS and fnbA genes among bovine isolates were significantly higher than those in human isolates, whilst the prevalence of cna gene was significantly higher in the human isolates. In this study, a high prevalence of biofilm production was found among S. aureus strains isolated from human and bovine infections. Most biofilm producing isolates were positive for MSCRAMM, icaA, and icaD genes.

Evaluation of biofilm production and characterization of genes encoding type III secretion system among Pseudomonas aeruginosa isolated from burn patients.

Pseudomonas aeruginosa is one of the common pathogenic causes of serious infections in burn patients throughout the world. Type III secretion toxins are thought to promote the dissemination of P. aeruginosa from the site of infection, the bacterial evasion of the host immune response and inhibition of DNA synthesis leading to host cell death. A total of 96 isolates of P. aeruginosa were collected from wound infections of burn patients, from April to July 2010. Antimicrobial susceptibility of the isolates were determined by disk agar diffusion method. Polymerase chain reaction (PCR)-based method was used for targeting the genes encoding the type III secretion toxins. The quantitative determination of biofilm-forming capacity was determined by a colorimetric microtiter plate assay. All the isolates were resistant to cefixime and ceftriaxone. More than 90% of the isolates were resistant to amikacin, carbenicillin, cefepime, cefotaxime, cefpodoxime, gatifloxacin, gentamicin, piperacillin/tazobactam, ticarcillin and tobramycin. All the isolates carried the exoT gene, 95% carried exoY, 64.5% carried exoU and 29% carried the exoS gene. Most of the isolates (58%) carried both exoY and exoU genes while 24% showed the concomitant presence of exoS and exoY and 1% carried both exoS and exoU. Coexistence of exoS, exoY and exoU was seen in 4% of the isolates. Biofilm formation was seen in more than 96% of the isolates among which 47% were strong biofilm producers, 26% were moderate and 22.9% were weak biofilm formers. In conclusion, the findings of this study show that the genes, particularly the exoU gene, encoding the type III secretion toxins, are commonly disseminated among the P. aeruginosa strains isolated from burn patients.

A high prevalence of mupirocin and macrolide resistance determinant among Staphylococcus aureus strains isolated from burnt patients.

Infections due to Staphylococcus aureus have become increasingly common among burn patients. The antibiotic resistance profile of S. aureus isolates and inducible resistance against clindamycin were investigated in this study. The presence of mecA gene, mupA gene and macrolide resistance genes were detected using PCR and multiplex-PCR. The resistance rate to methicillin, erythromycin and mupirocin were 58.5%, 58% and 40%, respectively. The prevalence of constitutive and inducible resistance among macrolide resistant isolates was 75% and 25%, respectively. Ninety five percent of the isolates were positive for one or more erm genes. The most common genes were ermA (75%), ermC (72%) and ermB (69%), respectively. The ermA gene predominated in the strains with the inducible phenotype, while ermC was more common in the isolates with the constitutive phenotype. The msrA gene was only found in one MRSA isolate with the constitutive phenotype. A total of 27 isolates (25%) carried the mupA gene. All the mupirocin resistant isolates and almost all the erythromycin resistant isolates were also resistant against methicillin which may indicate an outbreak of MRSA isolates with high-level mupirocin and erythromycin resistance in the burn unit assessed.

Time-kill study and synergistic activity of cell-wall inhibitor antibiotics in combination with gentamicin against Enterococcus faecalis and Enterococcus faecium.

The synergy between gentamicin and vancomycin, teicoplanin, ampicillin and linezolid was studied by time-kill method. Two clinical vancomycin resistant enterococci (VRE) and two vancomycin susceptible enterococci (VSE) isolates were used. Different concentrations of antibiotics were combined. Two VSE strains and the control strain exhibited synergism with the combination of gentamicin, vancomycin, teicoplanin, ampicillin and linezolid. Two VRE strains exhibited synergism with the combination of gentamicin and ampicillin. Synergy between gentamicin and vancomycin, teicoplanin and linezolid was not observed against these isolates. The VRE isolates were positive for vanA, aac (6')-Ie aph (2") and aph (3')-IIIa genes and their vancomycin, teicoplanin and gentamicin MICs were 512 µg/ml, 512 µg/ml and >4000 µg/ml, respectively. In order to treat serious enterococcal infections, further clinical evaluation is needed to examine the in vitro combined effects of gentamicin and vancomycin, teicoplanin and linezolid.

Characterization of Staphylococcus aureus strains isolated from raw milk of bovine subclinical mastitis in Tehran and Mashhad.

Staphylococcus aureus is considered one of the most important food borne pathogens. A total of 111 isolates of S. aureus were cultured from raw milk samples during January 2009 to June 2009 from Tehran and Mashhad. The coagulase gene polymorphism and the prevalence of classical enterotoxin genes of S. aureus strains were determined by PCR-RFLP (restriction fragment length polymorphism) and Multiplex-PCR. Disk diffusion method was used to determine the susceptibility of isolates to antimicrobial agents as instructed by Clinical and Laboratory Standards Institute. Sixty-seven % of the isolates harboured one or more enterotoxin genes. The most prevalent gene was sec, found in 59 % of the isolates. Approximately 8% of the isolates were positive for sea, seb and sed genes. Only one isolate had see gene. The rate of coexistence of enterotoxin genes was 14%. All S. aureus isolates were susceptible to ciprofloxacin, gentamicin, imipenem, minocycline, oxacillin and vancomycin. They were resistant to ampicillin (64%), penicillin (56%), clindamycin (22%), tetracycline (22%), doxycycline (19%), teicoplanin (13%), rifampin (2%) and trimethoprim-sulfamethoxazole (2%). On the basis of coagulase gene analysis of 111 S. aureus isolates, the PCR products of 56 isolates were digested with Alu I that produced three distinct patterns. These data indicate the high prevalence of enterotoxigenic S. aureus in raw bovine milk in Tehran and Mashhad, and highlight the importance of proper quality control of dairy products for public health.

Multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) and antibacterial resistance profiles of extended spectrum beta lactamase (ESBL) producing Pseudomonas aeruginosa among burnt patients in Tehran.

Extended spectrum ß-lactamase (ESBL)-producing trait was present in 48 out of the 112 (42.8%) Pseudomonas aeruginosa isolates collected from burn wound infections during a 12-month period. The presence of oxa-10, per-1, veb-1 and ges genes and the multiple-locus variable number of tandem repeats (VNTR) fingerprinting (MLVF) of 112 P. aeruginosa strains were determined by PCR and multiplex PCR. Disk diffusion methods were used to determine the susceptibility of the isolates to antimicrobial agents as instructed by CLSI. All ESBL isolates were resistant to aztreonam, cefepime, cefotaxime, cefpodoxime, ceftazidime, ceftriaxone and ofloxacin. Fewer than 60% of ESBL isolates were resistant to imipenem, meropenem, and piperacillin-tazobactam but more than 90% were resistant to amikacin, ciprofloxacin, levofloxacin, ticarcillin and tobramycin. The most prevalent ESBL genes included oxa-10 (70%) and per-1 (50%) followed by veb-1 (31.3%). The gene encodes GES enzyme did not detect in any isolates. A total of 100 P. aeruginosa strains were typed by MLVF typing method. MLVF produced 42 different DNA banding patterns. These data indicate that different MLVF types infect burn wounds in patients at a hospital in Tehran and also suggest an alarming rate of ESBL-producing isolates in this test location.

Molecular analysis and antimicrobial susceptibility of methicillin resistant Staphylococcus aureus in one of the hospitals of Tehran University of Medical Sciences: high prevalence of sequence type 239 (ST239) clone.

Methicillin-resistant Staphylococcus aureus (MRSA), particularly the multidrug-resistant clones, is an increasing worldwide problem. The average incidence rate of MRSA in Tehran was found to be over 40%. A total of 140 MRSA isolates obtained from patients attending a teaching hospital in Tehran, from May 2009 to December 2009, were included in this study. The antimicrobial susceptibility profile of MRSA isolates was determined by the agar disk diffusion method. Molecular analysis of MRSA strains was accomplished by Pulsed-Field Gel Electrophoresis (PFGE) and Multi-locus sequence typing (MLST). Detection of mecA gene was used to confirm resistance to methicillin among the MRSA isolates. All the MRSA isolates were susceptible to chloramphenicol, teicoplanin, tigecycline and vancomycin. All MRSAisolates were resistant to oxacillin, whilst 139 strains showed resistance against ciprofloxacin, erythromycin, gentamicin, tetracycline and trimethoprim-sulfamethoxazole. PFGE analysis of all the 140 MRSA isolates produced five distinct pulsotypes designated as pulsotypes A-E. Most of the isolates (n=132) were clustered into pulsotype A. The most prevalent sequence type (ST) was ST 239 (pulsotype A) found in 82% (37/45) of the tested isolates. The second most prevalent type was ST 1238 (pulsotypes B, C and D) found in 15% (7/45) of the isolates. The remaining type, ST 8 (pulsotype E) was found in a single isolate. The results of this study indicated that the MRSA clone ST 239 was a major clone in the selected university hospital of Tehran and that it was widely spread among the different wards as well as all the age groups of patients.

Multiple-locus variable number of tandem repeats fingerprinting (MLVF) and virulence factor analysis of methicillin resistant Staphylococcus aureus SCCmec type III.

Methicillin resistant Staphylococcus aureus (MRSA), particularly strains with type III staphylococcal cassette chromosome mec (SCCmec), represent a serious human pathogen in Tehran, Iran. The disease-causing capability depends on their ability to produce a wide variety of virulent factors. The prevalence of exotoxin genes and multiple-locus variable number of tandem repeats fingerprinting (MLVF) profile among MRSA isolates, from patients in Tehran, was evaluated by PCR and Multiplex-PCR. The MLVF typing of 144 MRSA isolates with type III SCCmec produced 5 different MLVF types. Generally, 97.2% (140/144) of all the isolates were positive for at least one of the tested exotoxin genes. The most prevalent genes were hld, found in 87.5% (126/144) of the isolates followed by lukE-lukD and hla found in 72.9% (105/144) and 70.1% (101/144) of the isolates, respectively. The tst gene, belonging to MLVF types I, IV and V, was found among three of the isolates from blood and wound samples. The sea gene was detected in 58.3% (84/144) of the isolates and the sed and see genes were found in one isolate with MLVF type V. The coexistence of genes was observed in the 87.5% (126/144) of the isolates. The rate of coexistence of hld with lukE-lukD, hla with lukE-lukD and sea with lukE-lukD were 66.7% (96/144), 44.4% (64/144) and 44.4% (64/144), respectively. The present study demonstrated that MRSA strains with type III SCCmec show different MLVF patterns and exotoxin profiles.