Identification Of Staphylococci Research Articles

1293. Efficacy of Doxycycline in Staphylococcal Prosthetic Joint Infection Treated with Debridement, Antibiotics and Implant Retention (DAIR) or Revision with Destination Spacer Placement

Abstract Background Prosthetic joint infection (PJI) is common, limb-threatening, and often warrants extended antibiotic durations. Intravenous (IV) glycopeptide, lipopeptide, and beta-lactam antibiotics have been the de facto US standard of care for staphylococcal PJI for decades, while the preponderance of (mostly European) published clinical data for PJI involves fluoroquinolone and rifampin combinations. However, these antibiotic strategies carry substantial adverse effects. In contrast, tetracyclines are less-studied for treatment of staphylococcal PJIs, but offer ease of administration and a favorable side effect profile. Methods We retrospectively evaluated the characteristics and outcomes of patients with staphylococcal PJI treated with doxycycline from March 2019 to April 2021 who received some period of outpatient parenteral antibiotic therapy (OPAT) and were included in our medical center’s OPAT database. We included patients with hip, knee, or shoulder PJIs managed with either debridement, antibiotics and implant retention (DAIR) or revision to a permanent “destination” spacer who received doxycycline within the first 12 weeks of therapy. Diagnosis of staphylococcal PJI was based on the documentation of the treating ID team plus identification of staphylococci in surgical tissue or synovial fluid cultures. Our primary outcome of interest was treatment failure, defined as reoperation for infection in the affected joint within one year of initial surgery. Results Of 24 patients switched to doxycycline after a mean 42 days, 17 underwent DAIR and 7 had destination spacers placed. 15 of 17 patients (88.2%) who underwent DAIR and 7 of 7 patients (100%) who received destination spacers remained free of treatment failure at one year; two patients had recurrent infections and none died. Conclusion These findings suggest that doxycycline is a safe and efficacious option for treatment of PJI. A key limitation of this study is patient identification via the OPAT database, meaning patients with short IV lead-in therapy (i.e. switch to PO at discharge) were not included, and that the efficacy of doxycycline is likely exaggerated by immortal time. Disclosures Angela Hewlett, MD, MS, Forcast Orthopedics: Advisor/Consultant|Mapp Biopharmaceutical: Grant/Research Support

Staphylococcus taiwanensis sp. nov., isolated from human blood.

A novel coagulase-negative Staphylococcus strain (NTUH-S172T) was isolated from human blood culture in Taiwan with preliminary identification of Staphylococcus saprophyticus. 16S rRNA gene analysis and multilocus sequence analysis (MLSA) showed that NTUH-S172T was most closely related to Staphylococcus haemolyticus. The average nucleotide identity and digital DNA-DNA hybridization values with the whole genome sequence were <95 % and<70 % when compared to the related species. Strain NTUH-S172T could be distinguished from S. haemolyticus by urease production and from Staphylococcus borealis by nitrate reduction. In addition, the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) spectrum of NTHU-S172T was significantly different from that of S. haemolyticus, which could be used in clinical identification. In conclusion, it is proposed that this isolate represents a novel species, named Staphylococcus taiwanensis sp. nov., with type strain NTUH-S172T (=BCRC 81315T=JCM 34726T).

Methicillin-resistant staphylococci among school children in Mariental, Namibia

Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to beta-lactam antibiotics, while some strains are multi-drug resistant and may produce disease-causing toxins. Drug resistant strains are often responsible for chronic, persistent and recurrent infections, which pose a challenge for healthcare practitioners. Our study aimed to determine the prevalence of nasal MRSA and methicillin-resistant coagulase-negative staphylococci (MRCoNS) among school children in the Mariental community, southern Namibia. This was a cross-sectional study in the Mariental District. Nasal specimens (swabs) were collected from 272 randomly selected learners aged 6–14 years attending school in the area during the months of March, September and October 2016. Isolation and identification of staphylococci were performed using standard microbiological methods. Methicillin-resistant isolates were identified by their resistance towards cefoxitin (30 µg) using the Kirby-Bauer disk diffusion assay. Enterotoxin production among multi-drug resistant MRSA isolates was detected with a SET-RPLA toxin detection kit. Methicillin-resistant S. aureus was isolated from 48 (17.6%) learners and MRCoNS from only seven (2.6%). Methicillin-resistant S. aureus colonization was significantly higher (P = 0.003) in the age group 11–14 years than in the group 6–10 years. Among the 433 staphylococcal isolates screened for cefoxitin resistance, 51 (11.8%) were MRSA and seven (1.6%) were MRCoNS. From the 51 MRSA isolates, 22 (43.1%) were multi-drug resistant of which six were enterotoxigenic. This is the first report on MRSA and MRCoNS among school children in Namibia. The presence of multi-drug resistant and potentially virulent staphylococci among school children in Mariental, Namibia, is of concern. Self-infection by these bacteria poses various health risks for the children. It is recommended that school health programmes improve current hygiene practices. Frequent handwashing can prevent staphylococcal disease and spread of resistant strains among learners and the wider community.

Isolation and antimicrobial resistance of Staphylococcus spp., enteric bacteria and Pseudomonas spp. associated with respiratory tract infections of sheep

Sheep are considered as an important part of livestock in the worldwide, particularly in Iraq, as they provide meat, milk, leather, wool, and manure. The present study aim is isolation and identification of staphylococci, enteric bacteria and Pseudomonas spp. Totally, 115 samples were collected from sheep (100 samples were collected from the nasal cavity of local sheep suffering from respiratory infections, and 15 samples were collected from apparently healthy local sheep). All the samples were collected from seven flocks located in Abu Ghraib and Al-Radwaniyah, Baghdad governorate, Iraq. The samples were taken during the period from October 2020 to February 2021. Staphylococcus spp., Pseudomonas spp., andenteric bacteria were detected firstly by using classical diagnostic methods, and secondly they were identified to the species level by using the corresponding analytical profile index (API 20 staph, API 20NE and API 20E) and via the Vitek2 system. Importantly, from nasal swabs, 79% bacterial isolates were obtained, including Enterobacter cloacae, Escherichia coli, Raoutltella planticola, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus among others. The antimicrobial susceptibility test showed multi-drug resistant S. aureus, P. aeruginosa and K. pneumoniae. To conclude, several aerobic bacteria were isolated from the nasal cavity of diseased sheep. An extensive study is needed to determine the economic and public health impacts of these bacteria.

A Study on the Prevalence and Source of Staphylococci and Methicillin-resistant Staphylococcus aureus Causing Superficial Incisional Surgical Site Infection

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) are common causatives of superficial incisional surgical site infection (SSI). The source of the pathogens is still not fully diagnosed whether it is endogenous or exogenous particularly with regard to the extent of its resistance to antibiotics. Therefore, this study is designed to determine the rate of infection, the source of pathogens, and the extent of their resistance to antibiotics. For this purpose, pre-, intra- and post-operative swabs from the nasal and skin of patients undergoing surgeries and samples from the hospital environment have been collected and processed for isolation and identification of staphylococci. Bacterial analysis and antibiotic susceptibility profiles of the isolates are assessed by unweighted pair group method with arithmetic mean (UPGMA) analysis based on random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and disc diffusion test for antibiotics susceptibility profile. The microbiological and PCR results indicate that SSIs are found in 113/512 (22.07%), Staphylococcus spp. rated 67/512 (13.09%) of infections. Further analysis indicates that S. aureus, CoNS, and both of them were causes SSI with different rates 41/67 (61.2%), 23/67 (34.3%), and 3/67 (4.5%), respectively. Results of RAPD-PCR for 70 isolates reveal that 52/70 (74.28%) of SSIs are from endogenous source, followed by 10/70 (14.29%) and 8/70 (11.43%) from hospitals acquired and undetermined sources, respectively. Moreover, results of antibiotic susceptibility test reveal that 24/44 (54.5%) of isolates belong to methicillin-resistant Staphylococcus aureus; from both endogenous and exogenous sources with 13/24 (54.17%) and 11/24 (45.83%), respectively.

Чутливість до антибіотиків штамів Staphylococcus aureus, що здатні до утворення біоплівки

The problem of respiratory diseases associated with staphylococcal carriers is considered to be one of the most acute in modern society due to its high prevalence and problems with treatment due to the high resistance of these bacteria to antibiotics. The purpose of the study was to determine the sensitivity of Staphylococcus aureus strains, able to form biofilm, isolated from the upper respiratory tract of human. Materials and methods. Bacteriological methods of isolation and identification of staphylococci, the method of rapid determination of the ability to form biofilm on a tablet and the disk-diffusion method of determining the susceptibility to antibiotics were used to perform the research. As a result of the conducted researches it was established that in the structure of pathogens of exacerbations of seasonal rhinitis S. aureus prevailed. It was isolated from 34 samples of biological material from the nose, which accounted for 69.4% of all examined cases of rhinitis. Staphylococcus spp. (6.1%) and Streptococcus spp. (24.5%) among the isolated strains of S. aureus, 27 (79.4%) had the ability to form a biofilm. A feature associated with antibiotic resistance is the ability of strains of microorganisms to form a biofilm, in which they acquire enhanced ability to survive under adverse environmental factors, including the use of drugs. Results and discussion. In our research we showed that more than 80% of film-forming strains were found to be susceptible to ciprofloxacin, amoxicillin / clavulanic acid and azithromycin. 4 (14.8%) are methicillin-resistant. Resistance to methicillin was detected simultaneously with resistance to ciprofloxacin (3 cases) and to azithromycin (2 cases), 1 strain was resistant to gentamicin and 2 – to tetracycline. 1 of the methicillin-resistant strains of S. aureus was multidrug-resistant (showed resistance to all studied antibiotics). Among non-biofilm strains, more than 80% of the strains were also sensitive to ciprofloxacin, amoxicillin / clavulanic acid and azithromycin. Sensitivity to tetracycline was low in both groups (42-63% sensitive). Conclusion. The prevalence of antibiotic resistance among clinical strains of opportunistic bacteria, unfortunately, shows an increasing trend. This requires constant monitoring of susceptibility to antimicrobial drugs in order to develop schemes of rational antibiotic therapy, taking into account the individualized approach to patients. In this sense, it is promising when studying the biological properties of clinical isolates to determine not only the resistance to antibiotics, but also their ability to form a biofilm

Identification of ovine-associated staphylococci by MALDI-TOF mass spectrometry

AbstractThe objective of this study was to use matrix-assisted laser desorption ionisation–time of flight mass spectrometry (MALDI-TOF MS) for the identification of ovine-associated staphylococci. Presumptive Staphylococcus isolates were recovered from ovine udder surface (US), individual raw milk, bulk tank milk, and cheese samples and were characterised by conventional phenotypic methods. A total of 69 bacterial isolates were further confirmed by MALDI-TOF MS. Forty-two (60.9%) of 69 isolates were successfully identified on genus and species level. Two thirds (n = 28) of the 42 identified isolates were shown to be Staphylococcus spp. These 28 staphylococcal isolates formed two clusters, one consisting of 22 Staphylococcus aureus strains and the other composed of 6 non-aureus staphylococci, including S. simulans (n = 3), S. auricularis, S. equorum, and S. haemolyticus. MALDI-TOF MS has proven to be a reliable tool for the identification of staphylococci from raw sheep's milk, especially bulk tank milk; however, currently it appears to be less useful for the identification of bacterial isolates originating from ovine US samples. This is the first study to evaluate the applicability of MALDI-TOF MS for identification of Staphylococcus spp. in ovine raw milk, cheese, and US samples in Hungary.

Isolation and Identification of Staphylococci and Pseudomonas from Diabetic Foot Ulcer in Perambalur District Hospitals in Tamil Nadu

Diabetic foot ulcers are still a problem for the health care system and are majorly influencing quality of life. Infected foot ulcer is one of the most feared complications of diabetes mellitus, leading to gangrene and it needs to be amputed. Diabetic foot lesions are major medical, social and economic problem and leading cause of hospitalization for patients with diabetes worldwide. The risk of a diabetic patient for developing a foot ulcer was estimated to be ~25%. Samples were collected from 65 infected patients of diabetic foot ulcer male and female. The mean age group was found to be 40-80 years with the clinical history such as age, sex, types of diabetes duration of diabetes, size of ulcer and duration of ulcer were observed and recorded. The Specific mediums were used for the isolation and identification using classical methods based on their morphology, Grams stain reaction, oxidase and catalase tests were performed to confirm the isolates were both gram-negative and gram-positive organisms Bergey’s manual of Determinative Bacteriology. Further, MALDI- TOF (Matrix-Assisted Laser Desorption/Ionization) was used to confirm the isolates identified in classical methods were Staphylococci (79%) and Pseudomonas (21%) In this study Among 68 isolates, identified in out of 41 isolates Pseudomonasaeruginosa (21%) Staphylococcus aureus (54%) Staphylococcus hominis (20%)and Staphylococcous hemolytic(5%). Although in gram positive organism Staphylococcus aureus (54%) was the most predominant isolate found in diabetic foot ulcer.

ПОРІВНЯННЯ ВПЛИВУ АНТИБІОТИКІВ ТА БАКТЕРІОФАГУ PHAGE SAVB14 НА БІОПЛІВКИ, СФОРМОВАНІ STAPHYLOCOCCUS AUREUS VARIANT BOVIS

Під час розвитку маститу у корів формування біоплівки збудником захворювання є ефективним способом його збереження в мікрооточенні молочної залози. Біоплівкові інфекції важко піддаються лікуванню антимікробними засобами, порівняно з тим, що спостерігається при вирощуванні в планктонних умовах. Мета роботи – визначити та порівняти вплив антимікробних препаратів та бактеріофагу Phage SAvB14 при знищенні біоплівок сформованих S. aureus var. bovis. За результатами дослідження встановлено, що антибіотики згубно впливали на кількість бактерій у складі біоплівки, проте знищували її, в середньому, на 60%. 100% ефективність проявляв лише один антибіотик фторхінолонового ряду – енрофлоксацин - ймовірно, через його низьку молекулярну масу. При дослідженні впливу бактеріофагу Phage SAvB14 на життєздатність S. aureus var. bovis у складі біоплівки встановлено, що фаг впродовж 24 годин повністю руйнував сформовану біоплвку. Отже, отримані результати вказують на перспективність ефективного використання стафілококового бактеріофагу Phage SAvB14 для руйнування біоплівки, сформованої S. aureus var. bovis – при маститі корів.

Identification of staphylococci causing mastitis in dairy cattle from Algeria and characterization of Staphylococcus aureus.

This study was conducted to determine the occurrence of staphylococci from cows with subclinical mastitis from independent herds in Algeria, and to characterize Staphylococcus aureus isolates. Quarter milk samples were collected separately, somatic cells were counted and samples with more than 200000 somatic cells per ml were cultured on blood agar. Staphylococci isolates were identified by routine diagnostics, and S. aureus isolates were tested for antibiotic susceptibility by disk diffusion and microdilution. Congo red agar was used to detect biofilm formation and capsule synthesis was detected on serum soft agar (SSA). The S. aureus isolates were characterized by spa typing. DNA microarray analysis was performed to detect resistance and virulence genes. Overall, 40·0% (167/418) of the cows suffered from mastitis. In 63·5% (106/167) of the cows staphylococci were identified. Nine of the 106 Staphylococcus isolates (8·5%) were S. aureus. The coagulase-negative staphylococci belonged to 14 species. All S. aureus isolates were multiresistant and biofilm forming, with 66·67% of them showing diffuse colonies on SSA and belonged to CC97-agrI-cap5. Biofilm genes (icaA/C/D), 13 genes encoding for adhesion, six genes encoding proteases, 11 genes encoding superantigen like toxins were found. Genes conferring resistance to tetracycline (tet(K)), penicillin (blaZ/I/R) and macrolide-lincosamide-streptogramin B (erm(B), erm(A)) were also detected in the S. aureus from this study. The current investigation provides a detailed molecular and biofilm formation ability of S. aureus involved in subclinical mastitis in Algeria and shows the wide distribution of adhesion and enterotoxin(-like) genes among S. aureus responsible for causing subclinical bovine mastitis. These findings are valuable in tracking the evolution and genomic variation of S. aureus from bovine origin.

Molecular Identification of Staphylococcus spp Isolated from Clinical samples

The analysis of 16S rRNA gene sequences has been the technique generally used to study and confirm the identification and taxonomy of staphylococci. However, bacterial species cannot always be distinguished from each other using cultural methods. Thus, clinical samples were collected from 190 cases only 31 positive for staphylococcal infections with Urinary Tract Infection, Wounds, Burns, Otitis media, diarrhea infections, were applied for microbiological analysis which include: cultures on Manitol salt agar and HiCrome UTI Agar medium all the isolates gave positive golden yellow and identify as Staphylococcus spp. DNA was extracted from Staphylococcus spp and the 16srRNA gene were amplified by using specific primer, then sequencing of nucleic acid of genes was performed by machine is AB13730XL, Applied Biosystem, Macro gen company, the DNA sequencing results of flank sense of 16srRNA gene from 31 strains of Staphylococcus was confirm the identification into species level: Staphylococcus haemolyticus, Staphylococcus aureus, Staphylococcus epidermidis And Staphylococcus sciuri. Analysis of the sequences appeared that there two substitution(Transversion, Transition) in the Staphylococcus aureus strains with Sequence ID LC090540.1 location at Range of nucleotide from 4 to 636, 100% compatibility with NCBI while no substitution appeared in the Staphylococcus haemolyticus strains which have the sequence ID LN998078.1, 99% compatibility with NCBI also the sequence ID KR812401.1 which related to the strain Staphylococcus sciuri not appeared any substitution after sequencing analysis. Types of substitution detected in partial 16srRNA gene in Staphylococcus epidermidis strains 13 Transversion and 5 transition substitution location at range of nucleotide from 6 to 1026 have the Sequence ID KF575160.1 compared with data obtained from Gene Bank, these finding lead to conclusion, our assay allows rapid and confirm the detection to avoid possibility of misidentification of Staphylococcus species based on cultural analysis, the study aimed to propose the partial sequencing of the gene as an alternative molecular tool for the analysis of Staphylococcus species and for decreasing the possibility of misidentification. New submission of local Iraqi Staphylococcus clinical isolated during the current study show successfully record of four isolate Staphylococcus sciuri, Staphylococcus epidermidis, Staphylococcus aureus and Staphylococcus haemolyticus with GenBank accession number: KY938530.1 ,KY938529.1, ,KY938528.1, and GenBank: KY938527.1respectivelly.

Identification and Antimicrobial Resistance Pattern of Staphylococci Isolated From Cottage Cheese (Ayib) and Yoghurt (Ergo) in Selected Districts of Jimma Zone, Ethiopia

Background: Staphylococci related illness is among serious public-health problems and the second most expensive diseases to treat in developing country. According to WHO estimation, staphylococcal related food borne disease are the second most common food borne disease next to salmonella. Although staphylococci related illness is affecting the majority of Ethiopian, much is not known about the extents of Staphylococcus species and their antimicrobial resistance pattern in cottage cheese (Ayib) and yoghurt (Ergo). Objectives: To investigate the occurrence of Staphylococcus, determine the prevalence of Staphylococcus and evaluate the antimicrobial resistance pattern of the isolates from cottage cheese (Ayib) and yoghurt (Ergo) collected from selected districts of Jimma Zone, Ethiopia. Methods: Identification of staphylococci was undertaken using Gram's staining, catalase, sugar fermentation and coagulase tests on cottage cheese (n=200) and yoghurt (n=200) samples collected randomly. The data were analyzed using SPSS version 20.0. Results: The overall prevalence of Staphylococcus in this study was found to be 14.3% with a specific prevalence of 22% in cottage cheese and 6.5% in yoghurt. The difference on the prevalence of staphylococci between cottage cheese and yoghurt was found to be statistically significant (P<0.05). The prevalence of Staphylococcus species was confirmed to be 5%, 3.5%, 3.3% and 5.8% for S. aureus, S. intermedius, S. hyicus and coagulase negative staphylococci (CNS) respectively. The specific prevalence in cheese and yoghurt for each species respectively were 7% and 3% (S. aureus), 5.5% and 1.5% (S. intermedius), 4% and 2.5% (S. hyicus), and 9.5% and 2% (CNS). The contamination of cottage cheese with staphylococcus was more likely to occur than yoghurt (OR=4.1, 95%, CI=2.1-7.8). The disc diffusion assay of 70 isolates against five biogram revealed the highest resistance to penicillin G (65.7%) followed by tetracycline (41.4%), streptomycin (37.1%), gentamycin (35.7%) and kanamycin (28.6%). Conclusion: The high prevalence of Staphylococcus and their high antimicrobial resistance pattern in cottage cheese and yoghurt in this study represent a poor keeping quality and indiscriminate use of drugs at the study area. This suggests the need to implement sanitary measures and awareness creations to improve the hygienic conditions of cheese and yoghurt from farm-to-table continuum as well as proper use of antimicrobials in order to guarantee the quality of these highly popular products and to safeguard the health of the consumers.

Impact of a rapid molecular test for positive blood cultures from neonatal intensive care patients on clinical management: a retrospective audit.

Both Staphylococcus aureus and coagulase negative Staphylococci are common causes of late-onset neonatal sepsis in the neonatal intensive care unit (NICU), usually relating to intravascular access device infections. This project aimed to review the impact on antimicrobial treatment and clinical outcome in the NICU setting, of the introduction of the Xpert MRSA/SA BC test (Cepheid, USA) for the identification of staphylococci in blood cultures. A retrospective audit was carried out of the pre- and post-intervention periods; the intervention was the introduction of the Xpert MRSA/SA BC test. In total, 88 neonates had positive blood cultures with Staphylococcus spp., comprising 42 neonates in the pre-intervention and 46 in the post-intervention groups. The pre-intervention group had a higher birth weight (1.541kg vs. 1.219kg, p=0.05) and higher platelet count (288 vs. 224×109/L, p=0.05). There was a trend towards a shorter duration of antimicrobial therapy in term infants and in the length of admission; however, this was not statistically significant (p=0.2). All of the nine infants post-intervention with significant bacteraemia (S. aureus =3, CoNS =6) were changed to the optimal antimicrobial at the time the result was available. This study shows that the introduction of the Xpert MRSA/SA BC test can lead to a reduction in the length of admission and duration of antimicrobials in term infants; however, the difference was not statistically significant. All nine infants with clinically significant bacteraemia were treated with the appropriate antimicrobial when the Xpert MRSA/SA BC test result was available.

Impact of enzymatic digestion on bacterial community composition in CF airway samples.

BackgroundPrevious studies have demonstrated the importance of DNA extraction methods for molecular detection of Staphylococcus, an important bacterial group in cystic fibrosis (CF). We sought to evaluate the effect of enzymatic digestion (EnzD) prior to DNA extraction on bacterial communities identified in sputum and oropharyngeal swab (OP) samples from patients with CF.MethodsDNA from 81 samples (39 sputum and 42 OP) collected from 63 patients with CF was extracted in duplicate with and without EnzD. Bacterial communities were determined by rRNA gene sequencing, and measures of alpha and beta diversity were calculated. Principal Coordinate Analysis (PCoA) was used to assess differences at the community level and Wilcoxon Signed Rank tests were used to compare relative abundance (RA) of individual genera for paired samples with and without EnzD.ResultsShannon Diversity Index (alpha-diversity) decreased in sputum and OP samples with the use of EnzD. Larger shifts in community composition were observed for OP samples (beta-diversity, measured by Morisita-Horn), whereas less change in communities was observed for sputum samples. The use of EnzD with OP swabs resulted in significant increase in RA for the genera Gemella (p < 0.01), Streptococcus (p < 0.01), and Rothia (p < 0.01). Staphylococcus (p < 0.01) was the only genus with a significant increase in RA from sputum, whereas the following genera decreased in RA with EnzD: Veillonella (p < 0.01), Granulicatella (p < 0.01), Prevotella (p < 0.01), and Gemella (p = 0.02). In OP samples, higher RA of Gram-positive taxa was associated with larger changes in microbial community composition.DiscussionWe show that the application of EnzD to CF airway samples, particularly OP swabs, results in differences in microbial communities detected by sequencing. Use of EnzD can result in large changes in bacterial community composition, and is particularly useful for detection of Staphylococcus in CF OP samples. The enhanced identification of Staphylococcus aureus is a strong indication to utilize EnzD in studies that use OP swabs to monitor CF airway communities.

Characterisation of a catalase-negative methicillin-resistant Staphylococcus aureus isolate from a dog

A catalase-negative MRSA strain and a methicillin resistant Staphylococcus pseudintermedius strain (MRSP) were isolated from a dog affected by a severe form of pododermatitis. The catalase negative isolate was typed as SCCmec I, PVL negative, ST5 t002 strain. A deletion at position 487 of the kat gene altered the functionality of the catalase enzyme. This is the first report of a catalase-negative MRSA in animals. As catalase test is a rapid assay routinely employed for the identification of staphylococci in clinical microbiology laboratories, the presence of MRSA with this uncommon phenotype may be underestimated. Moreover, catalase-negative staphylococci should be investigated more in-depth in order to assess their virulence.

Reliability of the MicroScan WalkAway PC21 panel in identifying and detecting oxacillin resistance in clinical coagulase-negative staphylococci strains

The purpose of this study was to determine the reliability of the MicroScan WalkAway PosCombo21 (PC21) system for the identification of coagulase-negative staphylococci (CNS) strains and the detection of oxacillin resistance. Using molecular and phenotypic methods, 196 clinical strains were evaluated. The automated system demonstrated 100 % reliability for the identification of the clinical strains Staphylococcus haemolyticus, Staphylococcus hominis and Staphylococcus cohnii; 98.03 % reliability for the identification of Staphylococcus epidermidis; 70 % reliability for the identification of Staphylococcus lugdunensis; 40 % reliability for the identification of Staphylococcus warneri; and 28.57 % reliability for the identification of Staphylococcus capitis, but no reliability for the identification of Staphylococcus auricularis, Staphylococcus simulans and Staphylococcus xylosus. We concluded that the automated system provides accurate results for the more common CNS species but often fails to accurately identify less prevalent species. For the detection of oxacillin resistance, the automated system showed 100 % specificity and 90.22 % sensitivity. Thus, the PC21 panel detects oxacillin-resistant strains, but is limited by the heteroresistance that is observed when using most phenotypic methods.

Development of a Modified Surveillance Definition of Central Line–Associated Bloodstream Infections for Patients with Hematologic Malignancies

To develop a modified surveillance definition of central line-associated bloodstream infection (mCLABSI) specific for our population of patients with hematologic malignancies to better support ongoing improvement efforts at our hospital. Retrospective cohort study. Hematologic malignancies population in a 1,200-bed tertiary care hospital on a 22-bed bone marrow transplant (BMT) unit and a 22-bed leukemia unit. An mCLABSI definition was developed, and pathogens and rates were compared against those determined using the National Healthcare Safety Network (NHSN) definition. By the NHSN definition the CLABSI rate on the BMT unit was 6.0 per 1,000 central line-days, and by the mCLABSI definition the rate was 2.0 per 1,000 line-days ([Formula: see text]). On the leukemia unit, the NHSN CLABSI rate was 14.4 per 1,000 line-days, and the mCLABSI rate was 8.2 per 1,000 line-days ([Formula: see text]). The top 3 CLABSI pathogens by the NHSN definition were Enterococcus species, Klebsiella species, and Escherichia coli. The top 3 CLABSI pathogens by the mCLABSI definition were coagulase-negative Staphylococcus (CONS), Pseudomonas aeruginosa, and Staphylococcus aureus. The difference in the incidence of CONS as a cause of CLABSI under the 2 definitions was statistically significant ([Formula: see text]). A modified surveillance definition of CLABSI was associated with an increase in the identification of staphylococci as the cause of CLABSIs, as opposed to enteric pathogens, and a decrease in CLABSI rates.

Identification of staphylococci and dominant lactic acid bacteria in spontaneously fermented Swiss meat products using PCR–RFLP

Pathogenic, spoilage, and technologically important microorganisms were monitored in 21 spontaneously fermented Swiss meat products manufactured with meat from wildlife or animals grown in natural habitat. Thereby, PCR–restriction fragment length polymorphism (RFLP) on rpoB and 16S rRNA gene sequences provided a powerful tool for fast and accurate identification of the main microbial population. Lactobacillus sakei and Lactobacillus curvatus dominated in fermented meat products followed by Staphylococcus species, which constituted 88.2% of all Gram-positive, catalase-positive cocci (GCC +) with cell counts varying from 2.6 to 7.0 log cfu/g during maturation. Staphylococcus equorum was prevalent in frequency and cell counts during maturation (18.0%; 5.0–7.3 log cfu/g) and in the end products (28.4%; 1.8–6.2 log cfu/g) implicating a new presumptive starter species for meat fermentation. Nine out of 14 end products indicated safety risks to consumers due to the high incidence of Staphylococcus saprophyticus or Staphylococcus epidermidis combined with cell counts of 7.4 and 4.9 log cfu/g, respectively. This fact was supported by the detection of Staphylococcus aureus and Enterobacteriaceae in ready-to-eat products strongly exceeding the tolerable limit of 2 log cfu/g. Spontaneously fermented meat products produced from wildlife or animals grown in natural habitats not only gave rise to hygienic and safety concerns but also provided new presumptive starter strains.

Detection and differentiation of staphylococcal contamination of clinical surfaces using denaturing gradient gel electrophoresis

The detection and identification of staphylococci from the environment of at-risk patients can be an important step in determining the role of the environment in hospital-acquired infections. Current methods that are used to identify these pathogens are either limited in their capabilities, expensive and/or labour intensive. We developed a denaturing gradient gel electrophoresis (DGGE) analysis protocol for the detection and identification of staphylococci that takes advantage of species-specific polymorphisms in the gene that encodes elongation factor Tu (tuf). The protocol was optimised by performing polymerase chain reaction (PCR)-DGGE analysis on DNA isolated from pure cultures of 27 different staphylococcal species. This resulted in the separation of the PCR products into 19 different band positions, including unique positions for important species such as Staphylococcus aureus, S. hominis, S. lugdunensis, S. warneri, S. capitis, S. caprae and S. saprophyticus. Application of the method was demonstrated by swabbing 15 clinical surfaces in an isolation room occupied by a patient before and after routine cleaning. PCR-DGGE analysis of tuf showed that despite cleaning efforts, the surfaces remained contaminated with several species of staphylococci, including S. aureus, S.epidermidis, S. lugdunensis, S. hominis, S. haemolyticus and S. simulans. We conclude that DGGE of tuf represents a promising technique for the detection, characterisation and monitoring of mixed assemblages of staphylococci in the healthcare environment.

İneklerin Süt, Meme Başı Derisi ve Burun Mukozalarından İzole Edilen Stafilokok Türlerinin Antibiyotik Direnç Profilleri

Summary The purposes of this study were to determine antibiotic resistance patterns of Staphylococcus spp. from isolated from milks, swabs from teat skins and noses mucosas of bovine in small and middle scale dairy farms. The samples were obtained from 109 head cows, randomly selected, reared in 14 small scale and 5 medium scale dairy farms in Kirikkale province. Isolation and identification of Staphylococci was made using biochemical tests and commercial micromethods (Crystal Gram-Positive Identification Kit, Becton Dickinson,USA). Resistance of Staphylococci spp. to various antibiotics were tested using disc diffusion test. Methicillin resistance of Staphylococci were determined using cefoxitin disc and oxacillin agar. Creature of β-lactamase enzyme was detected using β-lactamase (nitrocefin) identification stics (Oxoid). Forty-eight percent Staphylococcus aureus were isolated from bovine's milk samples in both small and medium scale dairy farms . S. aureus were isolated from in bovine's teat skin and noses mucosa swabs samples in small scale dairy farms, while S. aureus were not isolated from those of in middle scale dairy farms. It was applied to determine resistance by using 11 antibiotics which were blank to different antibiotic groups. Although the levels of resistance differed in origin of bovine' samples (noses mocosa- milk, between 19.5-49.5%), the highest percentage for resistance was obtained for penicillin. Methicillin resistant S. aureus was not isolated in this study. Of penicillin resistant Staphylococci, 92.7% (12) were found to be β-lactamase positive.