Enterotoxicity and genetic variation among clinical Staphylococcus aureus isolates in Jordan

Prevalence of enterotoxin genes (SEA to SEE) and antibacterial resistant pattern of Staphylococcus aureus isolated from clinical specimens in Assiut city of Egypt

Background

Infections in communities and hospitals are mostly caused by Staphylococcus aureus strains. This study aimed to determine the prevalence of five genes (SEA, SEB, SEC, SED and SEE) encoding staphylococcal enterotoxins in S. aureus isolates from various clinical specimens, as well as to assess the relationship of these isolates with antibiotic susceptibility. Traditional PCR was used to detect enterotoxin genes, and the ability of isolates expressing these genes was determined using Q.RT-PCR.

Results

Overall; 61.3% (n = 46) of the samples were positive for S. aureus out of 75 clinical specimens, including urine, abscess, wounds, and nasal swabs. The prevalence of antibiotic resistance showed S. aureus isolates were resistant to Nalidixic acid, Ampicillin and Amoxicillin (100%), Cefuroxime (94%), Ceftriaxone (89%), Ciprofloxacin (87%), Erythromycin and Ceftaxime (85%), Cephalexin and Clarithromycin (83%), Cefaclor (81%), Gentamicin (74%), Ofloxacin (72%), Chloramphenicol(59%), Amoxicillin/Clavulanic acid (54%), while all isolates sensitive to Imipinem (100%). By employing specific PCR, about 39.1% of isolates were harbored enterotoxin genes, enterotoxin A was the most predominant toxin in 32.6% of isolates, enterotoxin B with 4.3% of isolates and enterotoxin A and B were detected jointly in 2.1% of isolates, while enterotoxin C, D and E weren’t detected in any isolate.

Conclusion

This study revealed a high prevalence of S. aureus among clinical specimens. The isolates were also multidrug resistant to several tested antibiotics. Enterotoxin A was the most prevalent gene among isolates. The presence of antibiotic resistance and enterotoxin genes may facilitate the spread of S. aureus strains and pose a potential threat to public health.

NAuRA: Genomic Tool to Identify Staphylococcal Enterotoxins in Staphylococcus aureus Strains Responsible for FoodBorne Outbreaks

Food contamination by staphylococcal enterotoxins (SEs) is responsible for many food poisoning outbreaks (FPOs) each year, and they represent the third leading cause of FPOs in Europe. SEs constitute a protein family with 27 proteins. However, enzyme immunoassays can only detect directly in food the five classical SEs (SEA-SEE). Thus, molecular characterization methods of strains found in food are now used for FPO investigations. Here, we describe the development and implementation of a genomic analysis tool called NAuRA (Nice automatic Research of alleles) that can detect the presence of 27 SEs genes in just one analysis- and create a database of allelic data and protein variants for harmonizing analyses. This tool uses genome assembly data and the 27 protein sequences of SEs. To include the different divergence levels between SE-coding genes, parameters of coverage and identity were generated from 10,000 simulations and a dataset of 244 assembled genomes from strains responsible for outbreaks in Europe as well as the RefSeq reference database. Based on phylogenetic inference performed using maximum-likelihood on the core genomes of the strains in this collection, we demonstrated that strains responsible for FPOs are distributed throughout the phylogenetic tree. Moreover, 71 toxin profiles were obtained using the NAuRA pipeline and these profiles do not follow the evolutionary history of strains. This study presents a pioneering method to investigate strains isolated from food at the genomic level and to analyze the diversity of all 27 SE-coding genes together.

Molecular Characterization of Methicillin-Resistant Enterotoxin-Producing Staphylococcus aureus Isolated From Samosa and Falafel in Iran

Objective: This study aimed to determine the contamination rate of Staphylococcus aureus in Samosa and falafel as most popular snacks, detect the classic enterotoxins, mecA, and tst genes and investigate antimicrobial resistance in the isolates. Materials and Methods: The samples were examined using bacterial culture and the suspected isolates were characterized by biochemical tests. The identity of S. aureus isolates and the presence of enterotoxin-encoding genes were assessed using a multiplex polymerase chain reaction (PCR) assay and antibiotic resistance of the isolates was determined. Results: The results revealed that 56 (46.67%) samples were contaminated with S. aureus, among which 45 isolates (80.35%) were characterized as enterotoxigenic S. aureus. The highest prevalence rate belonged to sea encoding gene as 20 isolates (35.71%) were positive for this gene followed by sed gene which was detected in 14 S. aureus isolates (25%). Most isolates (75%) were resistant to cefoxitin. Moreover, the results of PCR assays indicated that 10 (17.58%) and 7 (12.5%) isolates were positive for mecA and tst genes, respectively. Conclusion: The results of the present study demonstrated that staphylococcal contamination of Samosa and falafel should be considered as a potential health risk for consumers.

Random amplified polymorphic DNA PCR in the teaching of molecular epidemiology

In this article, we describe a basic practical laboratory designed for fifth-year undergraduate students of Microbiology as part of the Epidemiology course. This practice provides the students with the tools for molecular epidemiological analysis of pathogenic microorganisms using a rapid and simple PCR technique. The aim of this work was to assay RAPD-PCR technique in order to infer possible epidemiological relationships. The activity gives students an appreciation of the value of applying a simple molecular biological method as RAPD-PCR to a discipline-specific question. It comprises a three-session laboratory module to genetically assay DNAs from strains isolated from a food outbreak. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(4):391-396, 2016.

Diversity of Virulence Factors Associated with West Australian Methicillin-Sensitive Staphylococcus aureus Isolates of Human Origin

An extensive array of virulence factors associated with S. aureus has contributed significantly to its success as a major nosocomial pathogen in hospitals and community causing variety of infections in affected patients. Virulence factors include immune evading capsular polysaccharides, poly-N-acetyl glucosamine, and teichoic acid in addition to damaging toxins including hemolytic toxins, enterotoxins, cytotoxins, exfoliative toxin, and microbial surface components recognizing adhesive matrix molecules (MSCRAMM). In this investigation, 31 West Australian S. aureus isolates of human origin and 6 controls were analyzed for relative distribution of virulence-associated genes using PCR and/or an immunoassay kit and MSCRAMM by PCR-based typing. Genes encoding MSCRAMM, namely, Spa, ClfA, ClfB, SdrE, SdrD, IsdA, and IsdB, were detected in >90% of isolates. Gene encoding α-toxin was detected in >90% of isolates whereas genes encoding β-toxin and SEG were detectable in 50–60% of isolates. Genes encoding toxin proteins, namely, SEA, SEB, SEC, SED, SEE, SEH, SEI, SEJ, TSST, PVL, ETA, and ETB, were detectable in >50% of isolates. Use of RAPD-PCR for determining the virulence factor-based genetic relatedness among the isolates revealed five cluster groups confirming genetic diversity among the MSSA isolates, with the greatest majority of the clinical S. aureus (84%) isolates clustering in group IIIa.

Prevalence, Molecular Characterization, and Antimicrobial Susceptibility of Methicillin-Resistant Staphylococcus aureus Isolated from Milk and Dairy Products

The present work was undertaken to study the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in raw milk and dairy products in Mansoura City, Egypt. MRSA was detected in 53% (106/200) among all milk and dairy products with prevalence rates of 75%, 65%, 40%, 50%, and 35% in raw milk, Damietta cheese, Kareish cheese, ice cream, and yogurt samples, respectively. The mean S. aureus counts were 3.49, 3.71, 2.93, 3.40, and 3.23 log10 colony-forming units (CFU)/g among tested raw milk, Damietta cheese, Kareish cheese, ice cream and yogurt, respectively, with an overall count of 3.41 log10 CFU/g. Interestingly, all recovered S. aureus isolates were genetically verified as MRSA strains by molecular detection of the mecA gene. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, sec) were detected in all isolates. The antimicrobial susceptibility pattern of recovered MRSA isolates against 13 tested antimicrobials revealed that the least effective drugs were penicillin G, cloxacillin, tetracycline, and amoxicillin with bacterial resistance percentages of 87.9%, 75.9%, 65.2%, and 55.6%, respectively. These findings suggested that milk and dairy products represent a potential infection risk threat of multidrug-resistant and toxigenic S. aureus in Egypt due to neglected hygienic practices during production, retail, or storage stages. These findings highlighted the crucial importance of applying more restrictive hygienic measures in dairy production in Egypt for food safety.

Both GtfA and GtfB are required for SraP glycosylation in Staphylococcus aureus

Staphylococcus aureus has been shown to bind to human platelets through a variety of surface molecules, including serine-rich adhesin for platelets (SraP). The SraP mutant strain of S. aureus is significantly impaired in its ability to initiate infection compared with the wild strain. SraP is a cell wall-anchored, glycosylated protein. A previous study revealed that SecY2, Asp1, Asp2, Asp3, and SecA2 in the SraP operon were required for the efficient transport of glycosylated SraP from the cytoplasm to the bacterial cell surface. However, no glycosyltransferase (Gtf) was found to be involved in the glycosylation of SraP. In this study, SraP was found in all of the 55 clinical isolates of S. aureus using a real-time polymerase chain reaction assay. Sequence and phylogenetic analysis showed that GtfA and GtfB in the SraP operon were highly conserved in most of these clinical isolates. Conserved domains analysis revealed that both GtfA and GtfB contained a GT1_GtfA-like domain. Structural homology analysis inferred that they are both Gtfs. We then constructed an in vivo glycosylation system in Escherichia coli using SraP1–743 as the substrate and GtfA and GtfB as the Gtfs. Using this system, we found that GtfA and GtfB were the Gtfs that transferred the N-acetylglucosamine-containing oligosaccharides to the recombinant SraP1–743. Deletion of either one or both of the Gtfs abolished the glycosylation of SraP. In summary, GtfA and GtfB in the SraP operon are highly conserved in most clinical isolates of S. aureus, and both GtfA and GtfB are required for SraP glycosylation.

Efficacy of standard vs. extended intramammary cefquinome treatment of clinical mastitis in cows with persistent high somatic cell counts

Extended duration of clinical mastitis (CM) treatment has been advocated, although results showing its higher efficacy compared with standard treatment are difficult to compare and seem conflicting. In a non-blinded, positively controlled clinical trial with systematic allocation, the efficacy of a standard, 1·5-d cefquinome treatment (ST), and an extended, 5-d intramammary cefquinome treatment (ET) were evaluated. The latter is frequently performed in cows with persistent high somatic cell count (SCC), expecting a better cure. Therefore, cows with CM immediately preceded by at least two consecutive monthly elevated SCC >200 000 cells/ml, were studied. The primary efficacy criteria were bacteriological cure (BC) and clinical cure (CC), while SCC cure was considered a secondary criterion of cure. Least square means of overall BC were not different after ET (79%, n=206) compared with ST (72%, n=203). ET, as compared with ST, improved BC of CM when caused by streptococci, specifically Streptococcus uberis. At day 1·5, only 13% of quarters showed CC, increasing significantly towards 60% at day 5, and 99% at day 14 and at day 21. No significant difference in CC was present between treatment groups. Overall SCC cure was low (22%) and not significantly different between treatment groups, but significantly higher for cases due to enterobacteriacae compared with staphylococci. In conclusion, ET with cefquinome of CM in cows with a persistent high SCC seems to be only indicated when caused by streptococci, mainly Str. uberis but shows no advantage when no information on bacteriological causes of mastitis is available. In our data, absence of CC directly after ST was not related to eventual BC.

Occurrence of Methicillin Resistant and Enterotoxigenic Staphylococcus aureus in Traditional Cheeses in the North West of Iran

Traditional dairy products are potential sources of a variety of microorganisms which participate in food poisoning. Staphylococcus aureus is a conspicuous example of toxigenic bacteria causative for food-borne diseases. Moreover, resistance to methicillin is a prominent index in food hygiene studies. In the present study, we have aimed at characterization and identification of enterotoxigenic methicillin resistant S. aureus (MRSA) isolated from traditional cheeses in Azerbaijan region in the northwest of Iran during 2012. A number of phenotypical and molecular assays were utilized for screening of S. aureus. Subsequently, the prevalence of the genes responsible for the five staphylococcal enterotoxins (SEA-SEE) and also methicillin resistance gene was assessed. The outcomes of phenotypical methods were in conformity with those of the molecular procedures. The results indicated that 16% of cheese samples were contaminated by S. aureus. 110 isolates were authenticated by both phenotypical and molecular methods. All of the mentioned isolates were positive for coa, nuc, and 16S rDNA primers. 21% of these isolates were mecA positive and 60.8% of these MRSA were positive for SEs. Regarding the frequent outbreaks of enterotoxigenic MRSA, new hygiene policies and management practices should be considered to increase food safety and avoid extra treatment costs.

Molecular characterization of foodborne-associated Staphylococcus aureus strains isolated in Shijiazhuang, China, from 2010 to 2012

Staphylococcus aureus is an opportunistic pathogen commonly identified from food poisoning-associated foodstuffs. From 1996 to the present, S. aureus isolates have been found to exhibit increasing resistance to antimicrobial drugs. The aim of this study was to assess the molecular epidemiology properties of various S. aureus isolates through molecular typing and to investigate their characterization based on their production of enterotoxins and hemolysins and their resistance to antibiotics. A total of 78 coagulase-positive staphylococcal strains isolated from food or clinical samples were analyzed. Eight VNTR loci were used to genotype the 78 isolates, and this analysis resulted in 39 different multilocus variable number tandem repeat analysis (MLVA) profiles. The isolates recovered from a single outbreak exhibited the same MLVA profile. According to CLSI, 97.4% of the isolates were resistant to penicillin, whereas only 3.8% were methicillin-resistant Staphylococcus aureus strains. Through multiplex PCR, 87.2% of the isolates were shown to be enterotoxigenic (SEs), and the most common genes present were sea, sem, seg, seu, and sek. In conclusion, this study demonstrates the prevalence of staphylococcal enterotoxins, the contents of virulent factors, and the characteristics of β-lactam antibiotic resistance in 78 S. aureus isolates. These findings emphasize the need to prevent the presence of S. aureus strains and SE production in foods. Our results also demonstrate that MLVA is a useful and powerful method for epidemiological studies of S. aureus. In contrast to multilocus sequence typing, the MLVA method is a simpler and more rapid method for epidemiological typing with a higher discriminatory power.

Major characteristics of Staphylococcus aureus colonizing Jordanian infants

BACKGROUND

Colonization of infants with methicillin-resistant Staphylococcus aureus (MRSA) carries specific toxin genes. In particular, Panton-Valentine leukocidin (PVL) are a risk factor for subsequent infection during hospitalization. This prospective study investigated important epidemiological characteristics of Staphylococcus aureus colonizing the nares and intestines of Jordanian infants.

METHODS

A total of 860 nasal and stool specimens were obtained from each of the 430 infants admitted to the neonatal intensive care unit or referred to outpatient clinics of Jordan University Hospital. All specimens were cultured to recover S. aureus, all isolates were tested for antimicrobial susceptibility and the MRSA strains for presence of specific toxin genes and SCCmec using polymerase chain reaction.

RESULTS

Eighty of the 430 (18.6%) infants were colonized with S. aureus, of these, 27 (6.3%) harbored the organism in both the nose and intestine. The frequency of S. aureus nasal and intestinal carriage in outpatient infants compared to inpatients admitted to the neonatal intensive care unit was significantly higher (27.3% vs 2.8%) and (17.1% vs 2.3%), respectively. MRSA accounted for 57/107 (53.3%) of all isolates, and of these 16/57 (28%) were PVL-positive and carried SCCmec type IV, except one, which was type III. All nasal and intestinal MRSA carried at least one toxin gene (tst, eta, seb), but few carried two toxin genes.

CONCLUSION

This study demonstrates that S. aureus strains are more frequently colonizing Jordanian outpatient infants than inpatients and all MRSA strains carried 1-3 clinically important staphylococcal toxin genes. Further studies are needed to investigate the role of these toxins in hospitalized infants.

Distinct cytokine profiles of circulating mononuclear cells stimulated with Staphylococcus aureus enterotoxin A in vitro during early and late episodes of chronic osteomyelitis

We investigated the cytokine profile of peripheral mononuclear cells from chronic osteomyelitis (OST) patients following in vitro stimulation with staphylococcal enterotoxin A (SEA). We demonstrate that stimulation with SEA induced prominent lymphocyte proliferation and high levels of tumour necrosis factor (TNF)-α, interleukin (IL)-4 and IL-10 secretion in both OST and non-infected individuals (NI). Even though stimulation with SEA had no impact on IL-6 production in either patient group, the baseline level of IL-6 production by cells from OST patients was always significantly less than that produced by cells from NI. After classifying the osteomyelitic episodes based on the time after the last reactivation event as "early" (1-4 months) or "late" osteomyelitis (5-12 months), we found that increased levels of TNF-α and IL-4 in combination with decreased levels of IL-6 were observed in the early episodes. By contrast, increased levels of IL-10, IL-2 and IL-6 were hallmarks of late episodes. Our data demonstrate that early osteomyelitic episodes are accompanied by an increased frequency of "high producers" of TNF-α and IL-4, whereas late events are characterised by increased frequencies of "high producers" of IL-10, IL-6 and IL-2. These findings demonstrate the distinct cytokine profiles in chronic osteomyelitis, with a distinct regulation of IL-6 production during early and late episodes.

Characterization of Staphylococcus aureus isolates from white-brined Urfa cheese

The aim of this study was to investigate the presence of Staphylococcus aureus and staphylococcal enterotoxin (SE) genes in Urfa cheese samples and to characterize the enterotoxigenic potential of these isolates. From a total of 127 Urfa cheese samples, 53 isolates (from 41.7% of the samples) were identified by a species-specific PCR assay as S. aureus. Of these isolates, 40 (75.5%) gave positive PCR results for the 3' end of the coa gene. The coa-positive S. aureus strains were characterized for their population levels and enterotoxigenic properties, including slime factor, β-lactamase, antibiotic susceptibilities, production of the classical SEs (SEA through SEE), in both cheese and liquid cultures by enzyme-linked immunosorbent assay (ELISA) and for the presence of specific genes, including classical SE genes (sea through see), mecA, femA, and spa, by PCR. The genetic relatedness among the coa-positive S. aureus isolates was investigated by PCR-based restriction fragment length polymorphism (RFLP) analysis and the 23S rRNA gene spacer. The 23S rRNA gene spacer and coa RFLP analysis using AluI and Hin6I revealed 14 different patterns. SEB, SEC, and SEA and SEE were detected by ELISA in three cheese samples. Fourteen S. aureus strains harbored enterotoxin genes sea through see, and three strains carried multiple toxin genes. The most commonly detected toxin gene was sec (25% of tested strains). Of the 40 analyzed S. aureus strains, 3 (7.5%) were mecA positive. Based on tandem repeats, four coa and spa types were identified. The results of this study indicate that S. aureus and SEs are present at significant levels in Urfa cheese. These toxins can cause staphylococcal food poisoning, creating a serious hazard for public health.

Toxins and Antibiotic Resistance in Staphylococcus aureus Isolated from a Major Hospital in Lebanon

Molecular characterization of Staphylococcus aureus is of both clinical and infection control importance. Virulence determinants using PCR and multiple drug resistance profiles were studied in 130 S. aureus isolates. PCR-RFLP analysis of the 16S-23S DNA spacer region was done to investigate the level of 16S-23S ITS (internal transcribed spacer) polymorphism. Methicillin-resistant S. aureus (MRSA), which represented 72% of the studied isolates, showed multiple drug resistance with 18% being resistant to 10-18 of the drugs used compared to a maximum resistance to 9 antibiotics with the methicillin sensitive S. aureus (MSSA) isolates. Exfoliative toxin A (ETA) was more prevalent than B (ETB) with virulent determinants being additionally detected in multiple drug-resistant isolates. 16S-23S ITS PCR-RFLP combined with sequencing of the primary product was successful in generating molecular fingerprints of S. aureus and could be used for preliminary typing. This is the first study to demonstrate the incidence of virulent genes, ACME, and genetic diversity of S. aureus isolates in Lebanon. The data presented here epitomize a starting point defining the major genetic populations of both MRSA and MSSA in Lebanon and provide a basis for clinical epidemiological studies.

The effects of subinhibitory concentrations of costus oil on virulence factor production in Staphylococcus aureus

AIM

To determine the antimicrobial activity of costus (Saussurea lappa) oil against Staphylococcus aureus, and to evaluate the influence of subinhibitory concentrations of costus oil on virulence-related exoprotein production in staph. aureus.

METHODS AND RESULTS

Minimal inhibitory concentrations (MICs) were determined using a broth microdilution method, and the MICs of costus oil against 32 Staph. aureus strains ranged from 0.15 to 0.6 μl ml(-1) . The MIC(50) and MIC(90) were 0.3 and 0.6 μl ml(-1) , respectively. Western blot, haemolytic, tumour necrosis factor (TNF) release and real-time RT-PCR assays were performed to evaluate the effects of subinhibitory concentrations of costus oil on virulence-associated exoprotein production in Staph. aureus. The data presented here show that costus oil dose dependently decreased the production of α-toxin, toxic shock syndrome toxin 1 (TSST-1) and enterotoxins A and B in both methicillin-sensitive Staph. aureus (MSSA) and methicillin-resistant Staph. aureus (MRSA).

CONCLUSION

Costus oil has potent antimicrobial activity against Staph. aureus, and the production of α-toxin, TSST-1 and enterotoxins A and B in Staph. aureus was decreased by costus oil.

SIGNIFICANCE AND IMPACT OF THE STUDY

The data suggest that costus oil may deserve further investigation for its potential therapeutic value in treating Staph. aureus infections. Furthermore, costus oil could be rationally applied in food products as a novel food preservative both to inhibit the growth of Staph. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins.

Phenotypic and Genotypic Characterization of Staphylococcus aureus Strains from Italian Dairy Products

Staphylococcus aureus is a known major cause of foodborne illnesses, and milk and dairy products are often contaminated by enterotoxigenic strains of this bacterium. In the present study, 122 S. aureus isolates collected from different dairy products were characterised by phenotypic properties, by the distribution of genes encoding staphylococcal enterotoxins (sea, sec, sed, seg, seh, sei, sej, and sel) and by randomly amplified polymorphic DNA PCR (RAPD-PCR). Moreover, strain resistance to vancomycin and methicillin (oxacillin) was studied. The differences in the RAPD-PCR profiles obtained with the primers M13 and AP4 revealed the presence of a great genetic heterogeneity among the different S. aureus strains. Using the primer AP4 and M13, eight groups were distinguished by RAPD-PCR cluster analysis, although, except in few cases, it was not possible to correlate the isolates of different animal species (cow or ovine) with the presence of se genes. None of the isolates showed resistance to vancomycin or methicillin.

Biochemical profiles, restriction fragment length polymorphism (RFLP), random amplified polymorphic DNA (RAPD) and multilocus variable number tandem repeat analysis (MLVA) for typing Staphylococcus aureus isolated from dairy products

The study concerns 130 Staphylococcus aureus strains isolated from different raw-milk dairy products (122 isolates) and human samples (eight isolates). Four different typing techniques were applied: biochemical profiles (Biolog GP), restriction fragment length polymorphism of coagulase gene (coaRFLP), random amplified polymorphic DNA (RAPD) and multilocus variable number tandem repeat analysis (MLVA). Moreover multiplex-PCR was used to study the distribution of genes encoding staphylococcal enterotoxins. The results of this study reveal marked genomic and phenotypic variability among the tested S. aureus. The considered techniques were all found useful for strain typing, but, based on discriminatory power as the key parameter of the typing system, MLVA and Biolog GP were found to be the most powerful techniques. The methods showed little concordance in terms of discerning the clusters of related strains.

Evolution of slime production by coagulase-negative staphylococci and enterotoxigenic characteristics of Staphylococcus aureus strains isolated from various human clinical specimens

The present study was designed to determine the slime production of coagulase-negative staphylococci (CoNS) and the enterotoxigenic properties of Staphylococcus aureus strains, and to evaluate the clinical importance of slime-producing CoNS and enterotoxigenic S. aureus strains isolated from various human clinical specimens. For this purpose, a total of 120 Staphylococcus strains were isolated and identified, and further characterized for their slime production and enterotoxigenicity. Of the clinical isolates, 55 (45.8 %) were found to be S. aureus, and the others (54.2 %) were identified as CoNS. Of the CoNS, 20 (16.7 %) were further identified as Staphylococcus hominis, 18 (15 %) as Staphylococcus epidermidis, six (5 %) as Staphylococcus xylosus, six (5 %) as Staphylococcus warneri, five (4.2 %) as Staphylococcus sciuri, four (3.3 %) as Staphylococcus haemolyticus, and two each (1.7 %) as Staphylococcus simulans, Staphylococcus capitis and Staphylococcus saprophyticus, respectively. Thirty-nine (60 %) of 65 CoNS were found to be slime producers. Slime production was observed in all CoNS, except S. capitis, mostly from blood (38.5 %), tracheal aspiration (20.5 %) and urine (12.8 %) specimens. In addition, of the 55 S. aureus isolates, 46 (83.6 %) were found to be enterotoxigenic, and of these S. aureus strains, 39 (84.7 %) were positive for staphylococcal enterotoxin (SE)A. The results of this study showed that the slime-producing CoNS were mostly found in clinical specimens of blood, tracheal aspirate and urine. SEA was the predominant enterotoxin type detected in S. aureus strains from human clinical specimens.

Persistent bacteraemia due to methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin in a patient with erythrodermic psoriasis

A 49-y-old male with erythrodermic psoriasis developed persistent bacteraemia for 3 months due to methicillin-resistant Staphylococcus aureus despite antimicrobial therapy. The skin was the likely focus. Three consecutive isolates from the blood and 1 from the nose were identical and had vancomycin MIC of 4 mg/l.

Detection of enterotoxin genes seg, seh, sei, and sej and of a novel aroA genotype in Jordanian clinical isolates of Staphylococcus aureus

The presence of staphylococcal enterotoxin (SE) genes (seg, seh, sei, and sej) and the correlation of their prevalence with the genotypes were studied in 100 clinical isolates of Staphylococcus aureus. Polymerase chain reaction (PCR) of SE genes indicated that 39% of the isolates were enterotoxigenic. Thirty-seven percent of the total isolates were seg positive, whereas 24% and 4% were sei and seh positive, respectively. All isolates containing sei were positive for seg, whereas sej gene was not detected. Genotyping by PCR-restriction fragment length polymorphism analysis of the aroA gene revealed that 39% of the isolates were type A and 11% were type B, and 50% displayed a novel (N) genotype. The presence of the enterotoxin genes was independent (P < 0.05) of the genotypes of the tested S. aureus isolates. This study has demonstrated that the seg was the most dominant enterotoxin gene and that the enterotoxigenic Jordanian S. aureus isolates belong to different genotypes, and N genotype was predominant.