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.

Significance of Coagulase Negative Staphylococci with Special Reference to Species Differentiation and Antibiogram.

Coagulase negative staphylococci (CoNS)are part of normal human flora increasingly recognized as significant nosocomial pathogens, infection often associated with implanted devices, joint prosthesis and different indwelling devices, especially in very young, old immunocompromised patients. Aims: To identify CoNS species, their distribution and antibiotic susceptibility pattern from different clinical samples. Method: A total 185 CoNS isolates were collected from various clinical samples followed for species identification by a practical scheme adapted using simple ,useful test selected from various references. Antibiotic susceptibility done by Kirby Bauer disc diffusion method. Results: The study yield that 185 CoNS,strains were isolated out of 1514 positive cultures from various clinical specimens. Among species ; S. epidermidis was the most commonly isolated species (68.65%), followed by S. heamolyticus (16.75%),followed by S. saprophyticus(9.8%)and few other species also identified. The antibiotic susceptibility pattern against commonly used antibiotic showed multidrug resistance with more than 90% resistance to penicillin and no strains was resistance to vancomycin. The methicillin resistance was 63% among all isolates of CoNS. Conclusions: Study suggest increasing pathogenic potential of CoNS as well as emerging of drug resistance amongst them, that necessitates the need to adopt simple laboratory procedure to identify CoNS species and understand definitive therapy for CoNS isolates from various clinical samples. This scheme was able to identified 98.9% isolates up to species level.

Evaluation of fuur different dna extraction metods in coagulase-negative staphhylococci clinical isolates / Avaliacao de quatro metodos diferentes de extracao de DNA em isolados clinicos de estafilococos coagulase negativos (SCoN)

Currently there are several methods to extract bacterial DNA based on different principles. However, the amount and the quality of the DNA obtained by each one of those methods is highly variable and microorganism dependent, as illustrated by coagulase-negative staphylococci (CoNS) which have a thick cell wall that is difficult to lyse. This study was designed to compare the quality and the amount of CoNS DNA, extracted by four different techniques: two in-house protocols and two commercial kits. DNA amount and quality determination was performed through spectrophotometry. The extracted DNA was also analyzed using agarose gel electrophoresis and by PCR. 267 isolates of CoNS were used in this study. The column method and thermal lyses showed better results with regard to DNA quality (mean ratio of A260/280 = 1.95) and average concentration of DNA (), respectively. All four methods tested provided appropriate DNA for PCR amplification, but with different yields. DNA quality is important since it allows the application of a large number of molecular biology techniques, and also it's storage for a longer period of time. In this sense the extraction method based on an extraction column presented the best results for CoNS.

Atualmente, para extrair o DNA bacteriano, existem diversos métodos baseados em diferentes princípios. Entretanto, a quantidade e qualidade do DNA obtido por cada um destes métodos é variável e depende do tipo de micro-organismo em questão; os estafilococos coagulase-negativos (CoNS), por exemplo, possuem parede celular espessa difícil de lisar. O objetivo deste estudo foi comparar a quantidade e a qualidade do DNA extraído de isolados clínicos de CoNS utilizando quatro metodologias diferentes: dois protocolos caseiros e dois kits comerciais. A determinação da quantidade e da qualidade do DNA foi realizada por espectrofotometria. O DNA extraído também foi analisado em eletroforese em gel de agarose e por PCR. A concentração média de DNA foi mais alta no método de lise térmica (). Entretanto, com relação à qualidade do DNA, o kit comercial que utiliza um método de extração baseado em uma coluna de separação apresentou melhor resultado (média da relação A260/280 = 1,95). As quatro técnicas testadas forneceram DNA passível de amplificação por PCR, porém com diferentes rendimentos. A qualidade do DNA extraído de bactérias é importante, pois possibilita a realização de maior número de técnicas de biologia molecular e também armazenamento do material por maior período de tempo. Neste sentido, a técnica de extração por coluna de separação apresentou melhor desempenho frente aos CoNS.

Stethoscopes as vectors of multi-resistant coagulase negative staphylococci in a tertiary hospital.

Background: Stethoscopes are an essential tool for physicians, but can be a source of hospital infections. Aims & Objective: The objective was to isolate staphylococci strains from the diaphragms and earpieces of the stethoscopes as well as to characterize their antibiotic resistance. Material and Methods: Forty five stethoscopes from different clinical doctors were sampled in a tertiary hospital. The swab method was used and the swabs were immediately inoculated on blood agar and manitol salt agar. The bacterial identification and the antibiotic resistance were performed according to the CLSI with automated commercial system. Results: Pathogenic or potential pathogenic Coagulase Negative Staphylococci (CoNS) were isolated on physician’s stethoscopes. CoNS were isolated in 87.6% of the stethoscopes. S.epidermidis was the predominant isolate species of CoNS (39.4%) followed by S.hominis (19.7%), S.auricularis (9.8%), S. haemolyticus (8.4%), S.warneri (7%), S. cohnii (5.6%), S. lugdunensis (4.2%), S. capitis (4.2%), S.hyicus (1.4%). The isolated CoNS have high resistance rate in penicillin (74.6%), antibiotic macrolidess (60.5%), clindamycin (39.4%), oxacillin (30.9%) and gentamycin (22.4%). The co-resistance of S.epidermidis for methicillin-gentamicin was 59.2%. Multi-resistant strains of CoNS were 16.9% and belong to the species of S.epidermidis, S.hominis and S.haemolyticus. Conclusion: The study demonstrates the contamination of the stethoscopes with different species of CoNS which showed high antibiotic resistance and possess the potential risk of causing hospital infections. As severe hospital infections, especially in population at risk caused by different species of CoNS, are increasing; their characterization at the species level as well as their resistance pattern in patients and medical devices is strongly suggested.

Urinary Tract Infection Due to Coagulase-negative Staphylococci: Species Identification, Antimicrobial Resistance and Clinical Characteristics / 대한임상미생물학회지

BACKGROUND: Previously considered as nonpathogenic contaminants, coagulase-negative staphylococci (CoNS) are now a major cause of nosocomial infections as increased use of prosthetic devices, intravascular catheters, and other invasive technology in more immunosuppressed patients and urinary tract infections (UTI) due to CoNS have been reported. In present study, species frequency, antimicrobial susceptability and clinical characteristics of CoNS UTI were evaluated. METHOD: We performed species identification and antimicrobial susceptibility of 109 CoNS strains isolated from urine in Ewha Womans University hospital from January 1998 to December 2002 and analysed clinical characteristics of 57 cases with CoNS UTI cases, retrospectively. RESULTS: Among 13,336 strains isolated from urine, 109 strains were CoNS showing 0.8%. The most common species of CoNS from urine were S. epidermidis (49.5%) followed by S. haemolyticus (16.5%), S. saprophyticus (13.8%), S. auricularis (1.8%), S. simulans (0.9%) and unidentified CoNS represented 17.4%. The antimicrobial susceptibility showed high resistance to multiple drugs. Among CoNS, S. haemolyticus showed the highest resistance whereas S. saprophyticus showed the highest susceptibility to multiple drugs. The patients isolated S. saprophyticus were younger (mean age: 41 yrs) than those isolated other CoNS (mean age: 53 yrs) and more frequently female (9/14 vs 19/43). The hospitalized patients (74.4% vs 21.4%), bacteriuria more than 10 5 CFU/ml (83.7% vs 64.3%), indwelling catheter (34.9% vs 7.1%) and other risk factors (48.8% vs 35.7%) were more common in patients isolated other CoNS than those isolated S. saprophyticus and no significant differences were noted in pyuria (51.2% vs 57.1%). The symptomatic presentations were more common in patients isolated S. saprophyticus than those isolated other CoNS (71.4% vs 9.3%) and so were treatment (85.7% vs 44.2%). CONCLUSIONS: When CoNS other than S. saprophyticus isolated from urine in hospitalized patientes with risk factors, identification and antimicrobial susceptability test is necessary for proper management.