Infección por Staphylococcus lugdunensis: descripción de 44 casos / Staphylococcus lugdunensis infection: report of 44 cases

INTRODUCCIÓN: Staphylococcus lugdunensis, es un estafilococo coagulasa negativa (SCN) con características de virulencia y de sensibilidad antimicrobiana que lo hacen más parecido a Staphylococcus aureus que a otros SCN. OBJETIVOS: Conocer las características clínicomicrobiológicas de los aislados de S. lugdunensis identificados en nuestra institución. MATERIAL Y MÉTODOS: Se realizó un estudio retrospectivo de los aislados de S. lugdunensis entre los años 2017 y 2019 en el Servicio de Microbiología del Hospital Universitario San Jorge de Huesca (España). Se revisaron las historias clínicas correspondientes a los pacientes con aislamiento de S. lugdunensis, considerándose las siguientes variables: edad, sexo, tipo de muestra, servicio de procedencia y enfermedad de base. La identificación bacteriana se realizó con MALDI-TOF VITEK MS (BioMérieux, Francia). Así mismo, se estudió su patrón de susceptibilidad antimicrobiana in vitro mediante microdilución en placa. RESULTADOS: Se obtuvieron 44 aislados de S. lugdunensis: 12 procedían de heridas, 10 fueron abscesos, 8 úlceras, 7 orinas, 4 frotis cutáneos, 2 exudados óticos, y 1 exudado vaginal. En relación con la enfermedad de base destacaron cinco pacientes con procesos tumorales y diez con diabetes mellitus. En 17 pacientes existían antecedentes de cirugía o traumatismo reciente. La mayoría de las cepas fueron sensibles a los antimicrobianos estudiados. En 19 de ellas se observó producción de β-lactamasa, dos fueron resistentes a macrólidos y tres a clindamicina. Todas las cepas fueron sensibles a oxacilina, gentamicina y cotrimoxazol. CONCLUSIONES: Aunque S. lugdunensis mantiene una buena sensibilidad a la mayoría de los antimicrobianos, su tendencia a producir abscesos y que exprese factores de virulencia más parecido a S. aureus que a otros SCN, hace necesaria una correcta identificación en el laboratorio con el fin de que su incidencia no quede subestimada.

BACKGROUND: Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CNS) with virulence and antibiotic sensitivity characteristics which makes it more similar to Staphylococcus aureus than other CNS. AIM: To know the microbiological and clinical characteristics of S. lugdunensis isolates identified from our health sector. METHODS: A retrospective study of S. lugdunensis isolates was carried out between 2017 and 2019 in the Microbiology Service of the San Jorge University Hospital in Huesca (Spain). The clinical records of patients with S. lugdunensis isolation were reviewed, considering the following factors: age, sex, sample type, service and underlying disease. Bacterial identification was performed using MALDI-TOF VITEK MS (BioMérieux, France). The pattern of antibiotic susceptibility was studied by means of plate microdilution. RESULTS: 44 isolates of S. lugdunensis were obtained: 12 corresponded to wounds, 10 were abscesses, 8 ulcers, 7 urine samples, 4 skin smears, 2 otic exudates, and 1 vaginal exudate. Regarding the underlying disease, five patients had a tumor processes and ten had diabetes mellitus. In 17 patients there was a history of recent surgery or trauma. Most of the strains were susceptible to the antibiotics studied. Production of beta-lactamase was observed in 19 of them, two were resistant to macrolides and three to clindamycin. None of the isolates were resistant to oxacillin, gentamicin or cotrimoxazole. CONCLUSIONS: Although S. lugdunensis maintains a good sensitivity to most antibiotics, its tendency to produce abscesses and that it expresses virulence factors more similar to S. aureus than to other CNS requires a correct identification in the laboratory so that its incidence is not underestimated.

Antibiotic resistance patterns of methicillin-resistant coagulase negative staphylococci isolated from blood cultures at a university hospital in Turkey

Aims@#Recent reports indicate that many coagulase-negative staphylococci (CoNS) strains are resistant to most antimicrobials used against staphylococcal infections. This study was aimed to determine the species distribution of the CoNS isolates in Lokman Hekim Ankara Hospital and determine their antimicrobial resistance characteristics.@*Methodology and results@#The study was conducted at Lokman Hekim University Ankara Hospital between February 2020 and August 2021. The 154 blood cultures included in the study were incubated in the BACTEC FX40 automated blood culture device. Identification and antimicrobial susceptibility tests of the samples with positive catalase tests were performed with the BD Phoenix Automated Microbiology Sensitivity System. The statistical significance level was accepted as p<0.05. Nineteen different types of methicillin-resistant coagulase-negative staphylococci (MRCoNS) isolated from different age groups were identified. Vancomycin resistance was observed in 20 samples (13%). Trimethoprim-sulfamethoxazole (TMP-SMX) resistance was seen in 44 of 152 samples (28.6%), linezolid resistance in 15 of 143 samples (10.5%) and daptomycin resistance in 16 of 146 blood samples (11%).@*Conclusion, significance and impact of study@#In our investigation, there has been a striking rise in the prevalence of vancomycin, TMP-SMX, linezolid and daptomycin resistance among infections with the MRCoNS. Identifying and classifying multidrug resistance on MRCoNS requires reliable epidemiological data to be collected and compared between healthcare facilities in different countries. The research finding reported in this paper will contribute to the determination of alternative antibiotics for treating MRCoNS.

Effect of donor-derived infection on clinical prognosis of kidney transplant recipients / 器官移植

Objective To evaluate the effect of donor-derived infection (DDI) on clinical prognosis of kidney transplant recipients. Methods Clinical data of 82 donors from donation after citizen's death and 148 kidney transplant recipients were retrospectively analyzed. According to the culture results of the lavage fluid of donor kidney, all recipients were divided into the lavage fluid culture of donor kidney positive group (positive group, n=92) and lavage fluid culture of donor kidney negative group (negative group, n=56). All recipients were assigned into the DDI group (n=19) and non-DDI group (n=129) according to whether they developed DDI or not. The distribution and composition ratio of positive strains in the lavage fluid of donor kidney were analyzed. The incidence of postoperative infection and other complications was assessed in the recipients. Perioperative conditions of the recipients were statistically compared between the DDI and non-DDI groups. The treatment efficacy and clinical prognosis of DDI recipients were evaluated. Results Among 148 recipients, 92 obtained positive culture results in the lavage fluid of donor kidney. A total of 131 pathogenic strains were isolated, including 41.2% (54/131) of Gram-positive cocci, 48.9% (64/131) of Gram-negative bacilli and 9.9%(13/131) of fungi. Among 148 recipients, 52 cases were infected. And 45% (41/92) and 20% (11/56) of the recipients were infected in the positive and negative group, respectively. Statistical significance was noted between two groups (P=0.002). Surgical site was the most common infection site in 52 infected recipients, followed by the urinary system. Nineteen recipients developed DDI with an incidence rate of 12.8% and fatality of 16%. Compared with the non-DDI recipients, DDI recipients had significantly higher graft loss rate and fatality, and longer postoperative hospital stay (all P < 0.05). Eight cases presented with carbapenem-resistant Klebsiella pneumoniae (CRKP) infection, after treatment with tigecycline and/or polymyxin and carbapenems, 3 cases died, and 3 underwent kidney graft resection. In the other 8 recipients with CRKP infection, 2 cases were treated with ceftazidime-avibactam (CAZ-AVI) alone, 3 treated with CAZ-AVI combined with carbapenems, and 3 initially treated with tigecycline combined with carbapenems followed by CAZ-AVI for salvage treatment. After corresponding treatment, the recipients achieved long-term survival. Conclusions DDI may lead to severe complications, while early specific antibacterial treatment plays a positive role.

Species distribution and clinical profiles of coagulasenegative staphylococci (CoNS) isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur

@#Introduction: Coagulase-negative staphylococci (CoNS) is often considered as a culture contaminants but it can potentially be pathogenic to patients with risk factors. A combination of species identification and clinical criteria has been suggested in determining true CoNS bacteraemia. Objectives: To identify the species distribution, antibiotic susceptibility patterns and clinical profiles of CoNS isolated from blood cultures among paediatric patients in Hospital Kuala Lumpur (HKL). Methods: This study involved CoNS isolation from blood cultures of paediatric in-patients of the Paediatric Institute HKL. Isolates were identified to species level using Analytical Profile Index Staph identification strips and antimicrobial susceptibility pattern following Kirby-Bauer Disc Diffusion method. The clinical profiles of patients were obtained from their medical records. Results: Eleven CoNS species were identified from 148 isolates. Staphylococcus epidermidis was the most frequent species isolated (67.6%). The majority of the isolates showed resistance to penicillin (85.8%); while 70.3% were methicillin-resistant (MR) CoNS, which demonstrated a significant association with true infection (p=0.021). Predictors for significant CoNS infection included thrombocytopaenia, presence of predisposing factors, nosocomial infection, blood collected from peripheral vein, and CoNS isolated from two consecutive blood cultures. The most common predisposing factors for the isolation of CoNS were the presence of peripheral (54.1%) and central venous catheters (35.1%). Conclusion: CoNS can cause significant bloodstream infections. The isolation of CoNS from blood cultures should be carefully interpreted by considering the predictive factors. Local data regarding predictive factors of patients with culture-positive CoNS, species distribution and antimicrobial susceptibility pattern are useful to determine the significance of blood culture results and care management of patients

Medically Important Coagulase Negative Staphylococci

In recent years, coagulase negative Staphylococci(CONS) are increasingly recognized as one of the major causes of health care associated infections (HCAI). CONS infections are one of the major causes of morbidity and mortality in hospitalized patients. As CONS colonize various parts of the skin and mucous membranes, most of infections are en-dogenous in origin. However, they are also transmitted exogenously via various medical/ surgical procedures. The aim of present review article is to update and summarize the information available on medically important CONS with special reference to epidemiology, laboratory diagnosis and antibiotic resistance.

Neonatal sepsis due to coagulase negative Staphylococci: a study from Kashmir valley, India

Background: Neonatal sepsis is a leading cause of neonatal mortality and morbidity. Early diagnosis and treatment with appropriate antibiotics are important to improve the prognosis of neonatal sepsis. Coagulase-negative Staphylococci (CoNS) have emerged as prominent pathogens in the neonatal intensive care unit. These infections are rarely fatal, but they cause significant morbidity, especially among very low birth weight infants. This study was done to know the prevalence of Coagulase-negative Staphylococci in neonatal sepsis and to determine their antibiotic susceptibility pattern.Methods: A prospective study was conducted on blood samples of suspected neonatal septicaemia between August 2017 and May 2018 received at Department of Microbiology, Government Medical College, Srinagar. Blood culture was done by automated blood culture system, (BacT/Alert) and identification and antibiotic susceptibility was done by VITEK2 method.Results: Out of 356 neonates screened, there were 185 (53.4%) positive blood cultures. Among the culture positive cases, 107 (57.83%) were male and 78 (42.16%) were female. Early Onset Septicaemia cases (130 [70.27%]) were found to be three times higher than late onset Septicaemia (55 [29.72%]). Coagulase-negative Staphylococci (CoNs) (30.27%) were the most common organisms isolated followed by Acinetobacter sp (15.1%), Klebsiella sp (5.4%) S. aureus (4.8%) and E. coli (4.8%). All the isolates of CoNS were sensitive to linezolid and vancomycin and tigecycline. Methicillin resistance was seen in 84% isolates.Conclusions: Present study highlights the emergence of Coagulase-negative Staphylococci (CoNS) as predominant cause of neonatal septicaemia. Most of the isolates were resistant to methicillin which is alarming and a cause for concern.

Comparison of antibiotic resistance spectrum between methicillin-resistant and methicillin-susceptible coagulase-negative staphylococci nasal isolates among 1 001 HIV infectors / 中华疾病控制杂志

Objective We aimed to elucidate the prevalence and the antibiotic resistance spectrum of nasal coagulase-negative staphylococci (CoNS) colonization among HIV infectors in Guangzhou. Method After isolation and identification, all CoNS isolates were tested for the antibiotic susceptibility, and the antibiotic resistance genes. Result Among the 1 001 HIV infectors, the prevalence of CoNS and MRCoNS were 57.44% and 48.15%, respectively. The three predominant resistant antibiotics of MRCoNS isolates were penicillin, erythromycin and trimethoprim-sulfame thoxazole, while predominant detection rates of genes were Aac(6’)-aph(2’)、ermC and linA genes. The multidrug resistance rate of MRCoNS isolates were significantly higher than methicillin-susceptible coagulase-negative staphylococci (MSCoNS) isolates (80.69% versus 39.66%, P<0.001, OR=6.36). Conclusions The prevalence and multidrug resistant rates of nasal colonization CoNS and MRCoNS are high among HIV infectors in Guangzhou. MRCoNS isolates were 6.36 times more likely to be of multidrug resistance than MSCoNS isolates.

Occurrence of II and V staphylococcal cassette chromosome mec types among coagulase-negative staphylococci from Northeastern part of India

Introduction: Coagulase Negative Staphylococci, the most commonly isolated pathogen are becoming emerging threats to the community as well as to the nosocomial environment. The present study underscores the distribution of Staphylococcal cassette chromosome mec (SCCmec) types among Methicillin resistant Coagulase Negative Staphylococci from the environmental origin. Methods and Materials: Environmental and food sample (n = 460) from different location of northeastern region of India were collected for a period of one year and were phenotypically and genotypically screened using cefoxitin disc and PCR techniques for mecA and mecC gene detection. All the MR-CoNS isolates possessing mecA gene were subjected to 16srDNA sequencing for species identification. SCCmec typing was determined by evaluating using primer sets from type I to type V. Antibiotic susceptibility testing was performed for all the isolates. Statistical analysis with chi-square test using SPSS-21 statistical software. Results: Methicillin resistance shown by one hundred forty three isolates were carried out for molecular analysis, among them 53.84% serves as mecA carrier. Distribution of Staphylococcus haemolyticus was more frequent and was found that SCCmec types II and V were predominant among the study isolates. Linezolid was the drug of choice for the CoNS isolates. Statistical analysis showed an insignificant result for the tested antibiotics and SCCmec types. Conclusion: This study therefore interprets the relative importance of SCCmec types among MR-CoNS isolates.

Assessment of different methods for the detection of biofilm production in coagulase-negative staphylococci isolated from blood cultures of newborns

Abstract INTRODUCTION: Coagulase-negative staphylococci (CoNS) are a frequent cause of bacteremia, especially in neonates. The major virulence determinant in CoNS is the ability to produce biofilms, which is conferred by the icaADBC genes. This study aimed to assess different methods for the detection of biofilm formation in 176 CoNS isolates from blood cultures of newborns. METHODS: The presence of the icaACD genes was assessed by polymerase chain reaction (PCR), and biofilm formation was assessed on congo red agar (CRA), by the tube method (TM), and on tissue culture plates (TCP). RESULTS: Of the 176 CoNS isolates, 30.1% expressed icaACD and 11.4% expressed icaAD. The CRA assay and TM showed that 42% and 38.6% of the isolates were biofilm producing, respectively. On TCP, 40.9% of the isolates produced biofilms; 21% were weakly adherent and 19.9% were strongly adherent. When compared to the gold standard technique (PCR), the CRAassay showed 79% sensitivity and 84% specificity (kappa = 0.64), TM showed 78% sensitivity and 89% specificity (kappa = 0.68), and TCP showed 99% sensitivity and 100% specificity (kappa = 0.99). CONCLUSIONS: In this study, ~42% of CoNS isolates produced biofilms, and the presence of icaACD was associated with a greater capacity to form biofilms. Compared to the other phenotypic methodologies, TCP is an ideal procedure for routine laboratory use.

Catarrhal mastitis by Staphylococcus simulans in a nulliparous goat / Mastite catarral causada por Staphylococcus simulans em uma cabra nulipara

The present paper is a case report of a one-year old nulliparous Alpine Goat belonging to a dairy goat farm in semi-arid region of Brazil. Both glands were naturally infected by α-hemolytic Staphylococcus simulans and evolved similar clinical signs. The mammary glands presented an acute catarrhal mastitis with systemic clinical signs that responded positively to treatment with gentamicin associated with amoxicillin. The present report suggests the importance of the pathogenic potential of non-aureus Staphylococci strains (NAS) as a cause of clinical mastitis also in nulliparous animals. The isolate showed resistance to tetracycline and contained staphylococcal toxin production genes (sec, sec and TSST-1). Moreover, it has been reported that Staphylococcus simulans is an emerging pathogen in humans causing cutaneous and osteoarticular infections, mainly in those in close contact with farm animals. To the best of our knowledge, this is the first report of a clinical mastitis in a nulliparous goat caused by Staphylococcus simulans(AU)

O presente trabalho é o relato do caso de uma cabra nulípara da raça Parda Alpina, de um ano de idade, pertencente ao Setor de Caprinocultura da Universidade Federal da Paraíba ­ Bananeiras - Brasil. Ambas as glândulas foram naturalmente infectadas por Staphylococcus simulans α-hemolítico. As glândulas mamárias apresentaram mastite aguda catarral com envolvimento sistêmico, respondendo positivamente ao tratamento sistêmico com gentamicina associada a amoxicilina. O presente relato sugere a importância do potencial patogênico de Staphylococcus não-aureus (SNA) como causador de mastite clínica também em animais nulíparos. O isolado mostrou resistência a tetraciclina e continha genes de produção de toxinas estafilocócicas (sec, seg e TSST-1). Além disso, tem sido relatado que Staphylococcus simulans é um patógeno emergente em seres humanos causando infecções cutâneas e osteoarticulares, principalmente naqueles que têm contato íntimo com animais de fazenda. Até onde sabemos, este é o primeiro relato de uma mastite clínica em uma cabra nulípara causada por Staphylococcus simulans.(AU)

Matrix-assisted laser desorption ionization-time of flight: a promising alternative method of identifying the major coagulase-negative Staphylococci species

Abstract INTRODUCTION. This study aimed to evaluate different methods for differentiation of species of coagulase-negative staphylococci (CoNS) that caused infections in hospitalized immunocompromised patients. METHODS. A total of 134 CoNS strains were characterized using four different methods. RESULTS. The results of matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) analysis were in complete agreement with those of tuf gene sequencing (kappa index = 1.00). The kappa index of Vitek 2® Compact analysis was 0.85 (very good) and that of the conventional method was 0.63 (moderate). CONCLUSIONS . MALDI-TOF MS provided rapid and accurate results for the identification of CoNS (134; 100%).

Clinical significance of coagulase-negative Staphylococci isolated from blood cultures / 中华传染病杂志

Objective To analyze clinical characteristics of bloodstream infections caused by coagulase-negative Staphylococci (CNS) and antibiotic resistance of the bacteria,so that to provide basis for the clinical diagnosis and treatment.Methods A retrospective analysis of CNS in blood cultures collected from 108 hospitalized patients in Puai Hospital of Tongji Medical College from January 2016 to December 2017 was performed.The antimicrobial susceptibilities were tested by Kirby-Bauer method and E test method.For measurement variables,normally distributed variables were compared using t test,and non-normal distributed data were compared using Mann-Whitney U test.Categorical variables were compared using x2 test.Results Of the 108 patients,66 were male and 42 were female;the age range was 26 to 98 years and the average was 49 years.According to the criteria for bacteremia,36 of 108 (33.3％) patients with CNS-positive blood cultures were diagnosed with bacteremia and 72 (66.7％) cases were contaminated.CNS bacteremia mainly occurred in the intensive care unit and nephropathy ward.Among them,23 (62.2％) patients were catheter-related blood stream infections,and 11 (29.7 ％) patients were dialysis catheter-related bloodstream infections.Fifteen of 36 (41.7％) strains were isolated within 48 hours of admission.The level of serum procalcitonin (PCT) for bacteremia patients was 2.56 (1.44,7.60) μg/L,and that was 0.13 (0.05,0.23) μg/L in contaminated patients.The difference was statistically significant (Z=8.097,P＜0.05).The white blood cell count of patients with bacteremia was (11.50±4.54) × 109/L,and that was (10.61 ±5.00) × 109/L for contaminated patients.There was no statistical significance (t=0.895,P＞0.05).After antibiotic treatment,26 of 36 bacteremia patients were survived.The PCT levels before antibiotic treatment were 2.05 (1.42,4.32) μg/L,and 0.24 (0.07,0.61) μg/L after antibiotic treatment.Serum PCT was decreased significantly after antibiotic treatment (Z=4.457,P＜0.05).The PCT levels of 10 deaths within 28 days before antibiotic treatment were 4.78 (1.51,19.75) μg/L,whereas 22 (6.40,55.75) μg/L,after antibiotic treatment.The PCT was increased significantly after antibiotic treatment (Z=2.497,P＜0.05).No significant difference was found in PCT between survivors and deaths within 28 days (Z=0.300,P＞0.05).No significant difference was found in white blood cell count between survivors and deaths at 28 days (t=0.771,P＞0.05).There was no statistical difference of the anti-bacterial drug susceptibility between pathogens and contaminants (P＞0.05).All strains were sensitive to vancomycin,teicoplanin and linezolid.Conclusions The incidence of CNS contamination in blood culture is relatively high.It is important to distinguish true bacteraemia from contamination by a review of the clinical and laboratory indicators.PCT is of clinical value to indicate CNS infection and to monitor therapeutic effect.

Clinical observation on the treatment of periprosthetic infection of coagulase-negative staphylococci by two-stage revision / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the risk factors for the failure in treating periprosthetic infection of coagulase-negative staphylococci by two-stage revision.</p><p><b>METHODS</b>From January 2005 to June 2015, 57 patients with periprosthetic hip and knee joint infection of coagulase-negative staphylococcus by two-stage revision were retrospectively reviewed with an average age of (61.3±11.9) years old. According to the drug resistance of methicillin, the patients were divided into methicillin sensitive group(MSCoN) and methicillin resistance(MRCoN) group, 25 cases in MSCoN group(9 knees and 16 hips) included 12 males and 13 females, 32 cases in MRCoN group(11 knees and 21 hips) included 14 males and 18 females. Follow-up for at least 2 years, the inflammatory markers, incidence rate of sinus and the duration of the symptoms, reinfection or persistent infection rate after two-stage revision were compared between two groups.</p><p><b>RESULTS</b>MSCoN group and MRCoN group were followed up(81.7±38.3) months and(65.9±33.8) months, respectively;23 cases and 27 cases were successfully treated;there was no significant difference between two groups(=0.643). The patients who had surgery history were 4.04 times higher of failure than the patients without a history of surgery[OR=4.04, 95%CI(0.62, 26.5)]. Patients who had sinus were 4.26 times higher of failure than the patients without sinus[OR=4.26, 95%CI(0.7, 25.9)].</p><p><b>CONCLUSIONS</b>Two-stage revision is an effective procedure in treating patients infected by MSCoN and MRCoN. There is no significant difference of treatment failure rate between MSCoN and MRCoN group by two-stage revision. Surgery history and sinus maybe the risk factors of treatment failure, while methicillin-resistance is not.</p>

Molecular identification of coagulase-negative staphylococci by rpoB sequence typing / 대한수의학회지

Bovine mastitis (BM) has resulted in enormous economic loss in the dairy industry and coagulase-negative staphylococci (CNS) have caused subclinical BM. Although VITEK 2 GP ID card (VITEK 2) has been used for CNS identification, the probability of identification varies. The rpoB sequence typing (RSTing) method has been used for molecular diagnosis and epidemiology of bacterial infections. In this study, we undertook RSTing of CNS and compared the results with those of VITEK2 and 16S rRNA gene sequencing. As compared VITEK2, the molecular-based methods were more reliable for species identification; moreover, RSTing provided more molecular epidemiological information than that from 16S rRNA gene sequencing.

Biochemical Characterization and Antibiotic Susceptibility of Coagulase Negative Staphylococci Isolates from Exudates and Body Fluids

Coagulase negative Staphylococci (CoNS) are increasingly being recognized as significant nosocomial pathogens, partly due to the growing appreciation of this group of organisms as opportunistic pathogens or due to increase in the use of transient or permanent medical devices in seriously ill and immunocompromised patients. Aims and Objectives 1) Isolation of CoNS from exudates and body fluids. 2) Biochemical characterization of CoNS. 3) Antibiotic susceptibility pattern of CoNS. Method 180CoNS isolated from various exudates and body fluids such as pus, wound swabs, endotracheal secretions, sputum, branchialaspitate, and central lining tube were collected. All the CoNS isolates were processed in the Microbiology Laboratory and identified by colony morphology, gram staining, catalase, slide, tube coagulase test, anaerobic acid from mannitol, and deoxyribonuclease. Bacitracin (0.04 U) and furazolidone (100 μg) susceptibilities were done to exclude Micrococcus and Stomatococcus spp. The following biochemical tests were done for the speciation of the CoNS: urease test, phosphatase test, polymyxin B disc test, novobiocin disk test, ornithine decorboxylase test, mannitol to acid, Voges-Proskauertest, mannose fermentation, trehalose fermentation and antibiotic susceptibility testing. Result Out of 180 isolates, 78 are Staphylococcus epidermidis (43.3%), 63 are Staphylococcus hemolyticus (35%), 21 are Staphylococcus hominis (11.6%), and 18 are Staphylococcus lugdunensis (10.0%). Maximum number of CoNS were isolated from pus specimens (58.33%), followed by wound swabs (18.33%). A total of 164out of 180 strains were negative for both bound and free coagulase. A total of 60 strains were bound coagulase slow positive and free coagulase negative. S. epidermidis was the most frequent isolate and 68 S. epidermidis isolates were identified if ornithine decorboxylase was considered positive, while negative 10 S. epidermidis isolates required inclusion of trehalose and mannitol for speciation. Antibiotic susceptibility testing showed maximum resistance to penicillin (78.3) followed by chloramphenicol (41.6%). No resistance to vancomycin was seen. Conclusion: The study revealed S. epidermidis is the predominant CoNS from endotracheal secretions and also pus samples. S. hemolyticus was isolated from pus and central lining tubes, S. hominis and S. lugdunensis were isolated mainly from wound swabs. The present study suggests if coagulase-ve Staphylococci are repeatedly isolated from patients with infection they should be taken seriously and ABST done on these isolates for proper diagnosis and treatment especially in nosocomial infections.

Analysis of virulence genes and antibiotics resistance of Staphylococci isolated from mastitis cows in parts of Guangdong province / 中国兽医学报

To evaluate the virulence genes and antibiotics resistance of Staphylococci species in mastitis cows isolated from parts of Guangdong,and then provide scientific basis of the prevention of bovine mastitis.Forty strains Staphylococci isolated from milk samples of 110 mastitis cows were collected,and virulence genes,resistance genes and disinfectant resistant genes were detected by PCR,and antibiotics resistance with K-B paper method.The results showed that the highest virulence gene was fnbp (17.5％),followed by seb (15％) and tsst (15％),and virulence genotype was complex.The most prevalent antibiotic resistance drug wvas streptomycin,followed by erythromycin and penicillin G,and CNS were susceptible to oxacillin,ceftraxone and cefazolin.The most prevalent antibiotic resistance genes was quinolones gene qnrA/B/C/D(20％),the resistance to streptomycin was mediated by aac6-aph2.The most prevalent disinfectant resistant gene was qacG (225 ％).The genotype of antibiotics resistance gene and disinfectant resistant gene was complex.

Detection of Integrons and Staphylococcal Cassette Chromosome mec Types in Clinical Methicillin-resistant Coagulase Negative Staphylococci Strains

OBJECTIVES: Integrons are thought to play an important role in the spread of antibiotic resistance. This study investigates class 1 and 2 integron-positive methicillin-resistant coagulase-negative staphylococci strains isolated in Iran and characterizes their patterns of antimicrobial resistance. METHODS: Hundred clinical isolates of coagulase-negative staphylococci were characterized for integron content and staphylococcal cassette chromosome mec (SCCmec) type. RESULTS: Sixteen isolates carried class 1 (intI1) integrons and four isolates carried class 2 (intI2) integrons. One resistance gene array was identified among the class 1 integrons (aadA1 cassette). The distribution of SCCmec types in 50 methicillin-resistant coagulase-negative staphylococci strains showed that SCCmec types III and V dominated among the tested strains. CONCLUSION: This is the first report of methicillin-resistant coagulase-negative staphylococci strains that carry two mobile genetic elements, including class 1 and 2 integrons and SCCmec, in Iran.

Coagulase‑negative staphylococci causing blood stream infection at an Indian tertiary care hospital: Prevalence, antimicrobial resistance and molecular characterisation.

Introduction: Recent years have seen a rise of coagulase‑negative staphylococci (CoNS) from common contaminants to agents of nosocomial blood stream infections (BSI’s). Molecular typing and establishing a correlation with antibiotic resistance is essential particularly in countries like India where genotyping studies for drug‑resistant CoNS are sparse. Methods: A prospective study was done over 18 months, wherein 42,693 blood samples were received, and 59 patients with BSI due to CoNS were evaluated. The isolates recovered were identified by a biochemical test panel and matrix‑assisted laser desorption ionization – time of flight mass spectrometry followed by antimicrobial susceptibility testing by Kirby–Baur disc diffusion method and E‑test strips. Staphylococcal chromosomal cassette mec (SCCmec) element was characterised by multiplex polymerase chain reaction for all methicillin‑resistant (MR) isolates. Results: The majority of CoNS isolated were constituted by Staphylococcus haemolyticus (47.5%) followed by Staphylococcus epidermidis (33.9%), Staphylococcus hominis (11.86%), Staphylococcus cohnii (5.08%) and Staphylococcus warneri (1.69%). Among all isolates 57.6% were MR with statistically significant higher resistance versus methicillin sensitive‑CoNS. This difference was significant for erythromycin (76% vs. 44%, P = 0.011), rifampicin (50% vs. 12%, P = 0.002) and amikacin (26.5% vs. 4%, P = 0.023), ciprofloxacin (64.7% vs. 20%, P = 0.001) and cotrimoxazole (55.9% vs. 20%, P = 0.006). SCCmec type I was predominant (61.8%, P = 0.028) and exhibited multidrug resistance (76.2%). Coexistence of SCCmec type I and III was seen in 8.82% MR isolates. Conclusion: CoNS exhibit high antimicrobial resistance thereby limiting treatment options. The presence of new variants of SCCmec type in hospital‑acquired CoNS may predict the antibiotic resistance pattern. This is the first evaluation of the molecular epidemiology of CoNS causing BSI from India and can serve as a guide in the formulation of hospital infection control and treatment guidelines.

The rising trend of coagulase‑negative staphylococci in neonatal septicemia.

Neonatal septicemia is one of the leading causes of neonatal mortality and morbidity worldwide. Hence, the present study was undertaken to isolate the bacteria causing neonatal sepsis and determine their antibiotic susceptibility pattern. Fifty neonates suspected to have septicemia were screened for 2 months (July and August 2014). Out of 50 specimen, 15 (30%) were blood culture positive. Coagulase‑negative staphylococci was the most common isolate (10, 66.6%), with 60% (6 isolates) methicillin resistance. In view of the increasing antibiotic resistance, periodic surveillance should be conducted to control the emergence and spread of antimicrobial resistance.

Molecular epidemiology of coagulase-negative bloodstream isolates: detection of Staphylococcus epidermidis ST2, ST7 and linezolid-resistant ST23

Abstract The mechanisms contributing to persistence of coagulase-negative staphylococci are diverse; to better understanding of their dynamics, the characterization of nosocomial isolates is needed. Our aim was to characterize phenotypic and molecular characteristics of Staphylococcus epidermidis and Staphylococcus haemolyticus human blood isolates from two tertiary care hospitals in Mexico, the Hospital Universitario in Monterrey and the Hospital Civil in Guadalajara. Antimicrobial susceptibility was determined. Biofilm formation was assessed by crystal violet staining. Detection of the ica operon and Staphylococcal Cassette Chromosome mec typing were performed by PCR. Clonal relatedness was determined by Pulsed-fiel gel electrophoresis and Multi locus sequence typing. Methicillin-resistance was 85.5% and 93.2% for S. epidermidis and S. haemolyticus, respectively. Both species showed resistance >70% to norfloxacin, clindamycin, levofloxacin, trimethoprim/sulfamethoxazole, and erythromycin. Three S. epidermidis and two S. haemolyticus isolates were linezolid-resistant (one isolate of each species was cfr+). Most isolates of both species were strong biofilm producers (92.8% of S. epidermidis and 72.9% of S. haemolyticus). The ica operon was amplified in 36 (43.4%) S. epidermidis isolates. SCCmec type IV was found in 47.2% of the S. epidermidis isolates and SCCmec type V in 14.5% of S. haemolyticus isolates. No clonal relatedness was found in either species. Resistance to clindamycin, levofloxacin, erythromycin, oxacillin, and cefoxitin was associated with biofilm production for both species (p < 0.05). A G2576T mutation in 23S rRNA gene was detected in an S. haemolyticus linezolid-resistant isolate. All linezolid-resistant S. epidermidis isolates belonged to ST23; isolate with SCCmec type IV belonged to ST7, and isolate with SCCmec type III belonged to ST2. This is the first report of ST7 in Mexico. There was a high genetic diversity in both species, though both species shared characteristics that may contibute to virulence.