Prévalence des staphylocoques à coagulase négative dans les hémocultures au Centre Hospitalier Universitaire Ibn Rochd de Casablanca

Introduction: la réalisation des hémocultures est le meilleur moyen de diagnostic des bactériémies, cependant les résultats faussement positifs peuvent entraîner une confusion concernant les schémas thérapeutiques antibiotiques, mettant ainsi en danger la sécurité des patients. L'objectif principal de ce travail est d'évaluer la prévalence des Staphylocoques à coagulase négative (SCN) ainsi que Corynebacterium spp et Bacillus spp dans les ballons d'hémoculture analysés au Laboratoire de Microbiologie du Centre Hospitalier Universitaire (CHU) Ibn Rochd de Casablanca. Cette prévalence a été aussi évaluée en fonction de différents services hospitaliers sur l'année 2016.Méthodes: il s'agit d'une étude rétrospective descriptive basée sur une analyse de la base de données informatisée du laboratoire de bactériologie-virologie du CHU Ibn Rochd de Casablanca sur une période de 12 mois allant du 1er janvier au 31 décembre 2016, Ont été inclus dans notre étude les bactéries faisant partie de la flore commensale (staphylocoque à coagulase négative,corynébactéries spp et Bacillus spp) Les ballons d'hémoculture ont été incubés sur automate Bactec FX . L'identification des germes à partir d'une culture positive a été réalisée selon les techniques standards de bactériologie et l'antibiogramme selon EUCAST 2015. L'étude est basée sur une analyse de la base de données informatisée du système KALISIL (Netika) version (2.2.10.) du laboratoire de microbiologie du CHU Ibn Rochd-Casablanca Maroc.Résultats: sur 7959 demandes d'hémocultures adressées au laboratoire de bactériologie provenant de 5801 patients, 2491 étaient positifs dont 848, soit 34% des ballons positifs ou 10,6% de l'ensemble des ballons reçus durant l'année 2016, ont été représentées par staphylocoque à coagulase négative, 56 soit (2,2%) ballons des hémocultures par corrynébacteruim SP, suivi par 60 soit (2,4%) ballons par bacillus sp. La fréquence d'isolement du SCN par rapport aux autres bactéries en fonction des services cliniques a montré une fréquence plus élevée dans les services de pédiatrie avec 47,2% suivie des services de médecine avec 44,1%. Conclusion: cette étude montre que, Les staphylocoques à coagulase négative sont les organismes les plus fréquemment isolés des hémocultures, ils constituent une cause non négligeable d'infections nosocomiales mais, ils sont également les contaminants les plus courants des hémocultures

Characterization and evaluation of antibiotic susceptibility pattern of coagulase negative staphylococci isolated from common clinical specimens in a Central Hospital in Delta State, Nigeria

The emergence of coagulase negative Stapylococci as major pathogens reflects the increased use of implants in hospitals. Fifty-four coagulase-negative staphylococci were isolated from a total of 242 clinical specimens at the Central Hospital, Kwale. All isolates were identified by standard bacteriological methods. Antibiotic sensitivity test was performed on all coagulase- negative staphylococci (CoNS) isolates using the modified Kirby-Bauer method with 10 different antibiotics. Staphylococcus epidermidis was the commonest species (83.3%), while Staphylococcus saprophyticus was 16.7%, mainly from urine samples. Highest sensitivity was found with ofloxacin (81.5%), followed by ciprofloxacin (77.8%) and, highest resistance occurred with cotrimoxazole to which no isolate was sensitive

Molecular Genotyping of Methicillin Resistant and Susceptible Staphylococcus Aureus by Coagulase Gene Polymorphism

Background: Methicillin-resistant Staphylococcus aureus (MRSA) which causes nosocomial infections is among the most important multi-resistant pathogens worldwide. Investigations of MRSA outbreaks in nosocomial settings often require strain-typing data to verify effectively that the isolates belong to the outbreak strain; and to discriminate similarity from unsimilarity strains. Quick and reliable typing methods are required to obtain information among MRSA isolates and to allow faster implementation of appropriate control measures. Objective : The aim of this study was to investigate genotyping of methicillin resistant and sensitive Staphylococcus aureus (MRSA and MSSA) in Khartoum Teaching Hospital; Sudan by using antibiotype and polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) of the coagulase gene. Methods: This is across sectional study. The samples were collected from clinical wound specimens in the wards of surgery; orthopaedic and burns at Khartoum Teaching Hospital; then processed; cultured and subsequently susceptibility test was performed using disc diffusion method. The MRSA strains were investigated by oxacillin 1[g disk diffusion method. PCR used to amplify a sequence of the coagulase (coa) gene; and the PCR products were analyzed by PCR-RFLP using Alu1 restriction enzyme. Result: Forty eight S. aureus strains were isolated and the number of MRSA identified was 9(18.75). All strains of MRSA and MSSA were sensitive to vancomycin; while multi-drug resistance was common among MRSA strains. PCR amplification products of coa gene were approximately at 500 bp (26/48); and 580 bp (22/48). By Alu1 restriction enzyme digestion of the PCR-amplified of coagulase gene; two distinct PCR-RFLP patterns exhibited; coaA and coaB and their fragments were approximately at 190; 310 bp and 190; 390 bp with percentages of 54.2(26/48) and 45.8(22/48) respectively. Conclusion: PCR-RFLP is considered an attractive tool for rapidly demonstrate the frequency of different patterns and discriminate the relatedness of isolates in different hospital wards

Species Distribution and Antibiotic Resistance in Coagulase-negative Staphylococci Colonizing the Gastrointestinal Tract of Children in Ile-Ife; Nigeria

Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife; Nigeria; was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional methods; and their susceptibility to 20 antibiotics was tested by disk diffusion and to vancomycin by agar dilution. Results: The species distribution was as follows: Staphylococcus epidermidis 45 (30.2); S. haemolyticus; 26 (17.5); S. capitis; 24 (16.1); S. xylosus; 11 (7.4); S. saprophyticus; 8 (5.4); S. warneri; 8 (5.4); S. hominis; 6 (4.0); S. schleiferi; 5 (3.3); S. lugdunensis; 3 (2.0) and S. capitis sub ureolyticus; 3 (2.0) and isolates from other CoNS species 10 (6.7). Resistance to the Beta-lactam antibiotics was in excess of 50of the isolates tested whilst there was significant incidence of resistance to cotrimoxazole; chloramphenicol; tetracycline; erythromycin; fusidic acid and norfloxacin. The highest percentage of oxacillin resistance was found among S. haemolyticus (46.2) while the lowest was in S. capitis (8.3). Reduced susceptibility (MIC = 4mg/L) to vancomycin was shown by both oxacillin-resistant and susceptible CoNS species. Conclusion: The gastrointestinal tracts of children could serve as a reservoir for antibiotic-resistant CoNS; some of which had reduced susceptibility to vancomycin

Species Distribution and Antibiotic Resistance in Coagulase-negative Staphylococci Colonizing the Gastrointestinal Tract of Children in Ile-Ife; Nigeria

Purpose: The antimicrobial susceptibility of 149 coagulase-negative staphylococci (CoNS) isolates from faecal samples of children in Ile-Ife; Nigeria; was evaluated in order to determine their contribution to antimicrobial resistance in the community. Methods: The isolates were identified to the species level by conventional methods; and their susceptibility to 20 antibiotics was tested by disk diffusion and to vancomycin by agar dilution. Results: The species distribution was as follows: Staphylococcus epidermidis 45 (30.2); S. haemolyticus; 26 (17.5); S. capitis; 24 (16.1); S. xylosus; 11 (7.4); S. saprophyticus; 8 (5.4); S. warneri; 8 (5.4); S. hominis; 6 (4.0); S. schleiferi; 5 (3.3); S. lugdunensis; 3 (2.0) and S. capitis sub ureolyticus; 3 (2.0) and isolates from other CoNS species 10 (6.7). Resistance to the - lactam antibiotics was in excess of 50of the isolates tested whilst there was significant incidence of resistance to cotrimoxazole; chloramphenicol; tetracycline; erythromycin; fusidic acid and norfloxacin. The highest percentage of oxacillin resistance was found among S. haemolyticus (46.2) while the lowest was in S. capitis (8.3). Reduced susceptibility (MIC 4mg/L) to vancomycin was shown by both oxacillin-resistant and susceptible CoNS species. Conclusion: The gastrointestinal tracts of children could serve as a reservoir for antibiotic-resistant CoNS; some of which had reduced susceptibility to vancomycin

Characterization of Staphylococcus Species Isolated from Raw Milk and Milk Products (lben and jben) in North Morocco

Background: To investigate the incidence and antibiotic resistance of staphylococcal strains isolated from milk and milk products and to trace the ecological origin of the Staphylococcus aureus isolated. Methodology: Eighty-one samples of raw milk; lben (whey) and jben (cheese) were analyzed for the presence of staphylococcal strains. Isolates were identified by Gram stains; tests for coagulase; the API staph system and the WalkAwayr 40/96; which also determines the antimicrobial susceptibility profiles. The S. aureus strains were biotyped; and variable regions of the coagulase gene were amplified using the polymerase chain reaction. Results: The identification results showed a predominance of coagulase-negative staphylococci (54). Coagulase-positive staphylococci that were identified were divided into 3 groups comprising S. aureus (40); Staphylococcus intermedius (2) and Staphylococcus hyicus (4). Among the S. aureus that was isolated; biotype C was the predominant biotype. Among 40 coagulase gene PCR-amplification products; 37 produced a single band; while 3 isolates produced two bands. The antimicrobial susceptibility-profile of the staphylococcal strains revealed a high incidence of S. aureus to penicillin G. In addition; Staphylococcus lentus presented considerable resistance to the oxacillin; erythromycin and lincomycin. Conclusions: The presence of staphylococci in raw milk; lben and jben in areas of northern Morocco poses a health hazard; so it is necessary for the public health inspectors to properly examine the conditions during production; storage and commercialization of all products made with unpasteurized milk. Key Words: milk products; Staphylococcus; coagulase-gene typing; biotyping; antimicrobial susceptibility