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Repurposing existing drugs is one approach to address the growing concerns of multi-drug resistant bacterial pathogens in veterinary medicine. Oxyclozanide is in the anthelmintic drug class salicylanilide, which has been used primarily as a treatment and preventative for Fasciola hepatica in ruminants. The antimicrobial activity of oxyclozanide has been studied in human medicine; its activity against common small animal bacterial pathogens such as Staphylococcus pseudintermedius has yet to be determined.The aim of this study was to measure and establish the minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) of oxyclozanide against S. pseudintermedius and other common small animal bacterial pathogens.The MIC and MPC of oxyclozanide were determined from eighteen meticillin sensitive S. pseudintermedius (MSSP) isolates and eleven meticillin-resistant S. pseudintermedius (MRSP), as well as single isolates of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis.The MIC of the eighteen meticillin-sensitive S. pseudintermedius isolates was 0.5-1 μg/mL and the MPC ranged between 16 and 32 μg/mL. The MIC of the eleven meticillin-resistant strains of S. pseudintermedius ranged from 0.5 to 2 μg/mL with a MPC ranging between 16 and 32 μg/mL. A single isolate of meticillin-resistant S. aureus (MRSA) had an MIC of 1 μg/mL and MPC 16 μg/mL. No inhibition of growth was seen at the concentrations tested for bacterial isolate strains E. coli, P. aeruginosa and E. faecalis.Oxyclozanide demonstrated in-vitro antibacterial activity against meticillin-resistant S. pseudintermedius. Further studies are needed to evaluate the potential use of oxyclozanide as a topical bactericidal agent.La réaffectation des médicaments existants est une option de gestion des préoccupations croissantes que sont les multirésistances bactériennes des pathogènes en médecine vétérinaire. L'oxyclozanide est un antihelmintique de la classe des salicylanilides, utilisé initialement comme traitement et prévention de Fasciola hepatica chez les ruminants. L'activité antimicrobienne de l'oxyclozanide a été étudiée en médecine humaine; son activité contre les pathogènes bactériens fréquents des petits animaux, tel que Staphylococcus pseudintermedius, doit encore être déterminée.Le but de cette étude était de mesurer et de déterminer la concentration minimale inhibitrice (MIC) et la concentration de prévention des mutants (MPC) de l'oxyclozanide contre S. pseudintermedius et d'autres bactéries pathogènes fréquentes chez les petits animaux. MATÉRIEL ET MÉTHODE: Les MIC et MPC de l'oxyclozanide ont été déterminés pour dix huit souches de S. pseudintermedius sensible à la méticiline (MSSP) et onze S. pseudintermedius résistant à la méticiline (MRSP), ainsi que les souches uniques de Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa et Enterococcus faecalis. RÉSULTATS: La MIC de dix huit souches de S. pseudintermedius sensible à la méticiline était de 0.5-1 μg/mL et les MPC variaient de 16 à 32 μg/mL. La MIC de onze souches de S. pseudintermedius résistantes à la méticiline variait de 0.5 à 2 μg/mL avec une MPC variant de 16 à 32 μg/mL. Une souche isolée de S. aureus résistante à la méticiline (MRSA) avait une MIC de 1 μg/mL et un MPC de 16 μg/mL. Aucune inhibition de croissance n'a été vue aux concentrations testées pour les souches bactériennes E. coli, P. aeruginosa et E. faecalis.L'oxyclozanide a démontré une activité antibactérienne in vitro contre S. pseudintermedius résistant à la méticiline. Des études supplémentaires sont nécessaires pour évaluer l'utilisation potentielle en tant qu'agent bactérien topique.INTRODUCCIÓN: el reenfoque en el uso de los medicamentos existentes es una posibilidad para abordar la creciente preocupación por la aparción de patógenos bacterianos resistentes a múltiples medicamentos en la medicina veterinaria. La oxiclozanida se encuentra en la clase de medicamentos antihelmínticos salicilanilida, que se ha utilizado principalmente como tratamiento y preventivo frente a Fasciola hepatica en rumiantes. La actividad antimicrobiana de la oxiclozanida ha sido estudiada en medicina humana; su actividad frente a patógenos bacterianos de animales pequeños comunes como Staphylococcus pseudintermedius aún no se ha determinado. OBJETIVO: el objetivo de este estudio fue medir y establecer la concentración inhibitoria mínima (MIC) y la concentración de prevención de mutaciones (MPC) de oxiclozanida frente a S. pseudintermedius y otros patógenos bacterianos comunes de animales pequeños. MÉTODOS Y MATERIALES: la MIC y la MPC de la oxiclozanida se determinaron a partir de dieciocho aislamientos de S. pseudintermedius (MSSP) sensibles a la meticilina y once aislamientos de S. pseudintermedius (MRSP) resistentes a la meticilina, así como aislamientos aislados de Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa y Enterococcus faecalis. RESULTADOS: la MIC de los dieciocho aislamientos de S. pseudintermedius sensibles a la meticilina fue de 0.5 a 1 μg/ml y la MPC osciló entre 16 y 32 μg/ml. La MIC de las once cepas de S. pseudintermedius resistentes a la meticilina osciló entre 0.5 y 2 μg/ml, con una MPC que osciló entre 16 y 32 μg/ml. Un único aislado de S. aureus resistente a meticilina (MRSA) tuvo una MIC de 1 μg/mL y MPC de 16 μg/mL. No se observó inhibición del crecimiento en las concentraciones analizadas para cepas aisladas de bacterias E. coli, P. aeruginosa y E. faecalis. CONCLUSIÓN E IMPORTANCIA CLÍNICA: la oxiclozanida demostró actividad antibacteriana in vitro frente a S. pseudintermedius resistente a la meticilina. Se necesitan estudios adicionales para evaluar el uso potencial de la oxiclozanida como agente bactericida tópico.Kratzverhalten in Zusammenhang mit einer intradermalen (i.d.) Injektion von Pruritogenen wie Histaminen und Compound 48/80 in die Haut von Mäusen und Menschen ist ein häufig verwendetes Modell, um die Forschung über den Juckreiz und die Entwicklung von Medikamenten voranzubringen. Die prädiktive Validität dieses Modells ist bei Hunden noch wenig beschrieben.Eine Evaluierung der Dosis-abhängigen Wirkungsweisen von pruritogenen Substanzen, mit einer jeweils anderen Wirkungsweise, bei gesunden Hunden.Zehn gesunde Beagles aus dem Versuchslabor.Alle Hunde wurden für 30 Minuten nach i.d. Injektion von Ziegen Anti-canine IgE (4 und 25 µg/Hautstelle), Histamin und Compound 48/80 (50, 100, 200, 400 µg/Hautstelle) über Video aufgenommen; zwei Injektionen mit gepufferter Kochsalzlösung dienten als Kontrollen. Zwei geblindete UntersucherInnen sahen das Juckreizverhalten auf allen Videoaufnahmen durch. Es wurde ein Global Wheal Score nach 30 mpi durch einen geblindeten Untersucher erfasst.Alle Hunde zeigten eine Quaddelbildung und Erythem an der Injektionsstelle des Pruritogens; der Global Wheal Score einer jeden Substanz nahm 30 mpi in allen Konzentrationen im Vergleich zu den Kontrollen signifikant zu (P ≤ 0.05). Eine geblindete Evaluierung zeigte, dass alle Pruritogene ein mildes akut juckendes Verhalten an der Injektionsstelle auslösten. Bei keinem der Hunde konnte an der Injektionsstelle ein Schmerz festgestellt werden. Im Vergleich zu den Kontrollen beeinflussten die Injektionen der pruritogenen Substanzen für keine derselben die Anzahl der Juckreizsekunden oder das Auftreten von Juckreizepisoden.Diese vorläufigen Ergebnisse zeigen, dass i.d. Injektionen der untersuchten Pruritogene kutane Quaddeln und Schübe bei gesunden Hunden auslösen können; allerdings treten Uneinheitlichkeiten bei der Auslösung des Juckreizes selbst mit den unterschiedlichen Konzentrationen der Pruritogene auf.背景: 既存の薬物を再利用することは、獣医学における多剤耐性細菌性病原体の高まる懸念に対処するための1つのアプローチである。オキシクロザニドは、反芻動物における肝蛭治療および予防剤として主に使用されてきた駆虫薬クラスのサリチルアニリドである。オキシクロザニドの抗菌活性は人医学で研究されている。 しかし、Staphylococcus pseudintermediusのような一般的な小動物の細菌性病原体に対する活性はいまだ決定されていない。 目的: 本研究の目的は、S. pseudintermediusおよび他の一般的な小動物細菌性病原体に対するオキシクロザニドの最小発育阻止濃度(MIC)および耐性菌出現阻止濃度(MPC)を測定し確立することであった。 材料および方法: オキシクロザニドのMICおよびMPCを、メチシリン感受性S. pseudintermedius(MSSP)18株およびメチシリン耐性S. pseudintermedius(MRSP)11株、ならびにStaphylococcus aureus、Escherichia coli、Pseudomonas aeruginosaおよびEnterococcus faecalisの単一株によって決定した。 結果: メチシリン感受性S. pseudintermedius 18株のMICは0.5〜1μg/ mLであり、MPCは16〜32μg/ mLの範囲であった。メチシリン耐性S. pseudintermedius11株のMICは0.5〜2μg/ mLであり、MPCは16〜32μg/ mLの範囲であった。メチシリン耐性S. aureus(MRSA)の単一株は、1 μg/mLのMICおよび16 μg/mLのMPCを有した。細菌分離株E.coli、P. aeruginosaおよびE. faecalisについて、試験した濃度では増殖阻害は見られなかった。 結論と臨床的重要性: オキシクロザニドはメチシリン耐性S. pseudintermediusに対してin vitro抗菌活性を示した。外用殺菌剤としてのオキシクロザニドの潜在的使用を評価するためにはさらなる研究が必要である。.背景: 兽医领域中致病的多重耐药菌日益增长,重新利用现有药物是解决这一问题的方法。羟氯柳苯胺属于水杨酰苯胺类驱虫药,主要用于反刍动物中肝片吸虫的治疗和预防。人类医学中已经研究了羟氯柳苯胺的抗菌活性;其对抗常见的小动物致病菌如假中间型葡萄球菌(S. pseudintermedius)的活性尚未确定。 目的: 本研究的目的是测量和建立羟氯柳苯胺对假中间型葡萄球菌和其他常见小动物致病菌的最小抑菌浓度(MIC)和突变预防浓度(MPC)。 方法和材料: 测定羟氯柳苯胺对十八株甲氧西林敏感假中间型葡萄球菌(MSSP)和十一株耐甲氧西林假中间型葡萄球菌(MRSP),以及单株金黄色葡萄球菌、大肠杆菌、铜绿假单胞菌和粪肠球菌的MIC和MPC。 结果: 羟氯柳苯胺对18株甲氧西林敏感假中间型葡萄球菌的MIC为0.5-1μg/ mL,MPC为16至32μg/ mL;对11株耐甲氧西林假中间型葡萄球菌的MIC范围为0.5至2μg/ mL,MPC范围为16至32μg/ mL;对单株耐甲氧西林金黄色葡萄球菌(MRSA)的MIC为1μg/ mL,MPC为16μg/ mL;对特定浓度的大肠杆菌、铜绿假单胞菌和粪肠球菌测试中,未观察到生长抑制。 结论和临床意义: 羟氯柳苯胺显示出对抗耐甲氧西林假中间型葡萄球菌具有体外抗菌活性,需要进一步的研究来评估羟氯柳苯胺作为外部杀菌剂的潜在用途。.O reaproveitamento de fármacos existentes em diferentes funções é uma alternativa adequada para abordar a preocupação crescente com a multirresistência em patógenos bacterianos. A oxiclozanida é um fármaco anti-helmíntico da classe das salicilanilida, que tem sido usada primariamente no tratamento e prevenção da Faciola hepatica em ruminantes. A atividade antimicrobiana da oxiclozanida tem sido estudada em medicina humana; a sua atividade antimicrobiana contra patógenos bacterianos comuns como o Staphylococcus pseudintermedius ainda não foi determinada.O objetivo deste estudo foi mensurar e estabelecer a concentração inibitória mínima (MIC) e a concentração de prevenção de mutantes (MPC) da oxiclozanida contra S. pseudintermedius e outros patógenos comuns em pequenos animais. MÉTODOS E MATERIAIS: O MIC e MPC da oxiclozanida foram determinados para dezoito isolados Staphylococcus pseudintermedius sensível à meticilina (MSSP) e onze Staphylococcus pseudintermedius resistente à meticilina (MRSP), bem como isolados únicos de Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa e Enterococcus faecalis.O MIC dos dezoito S. pseudintermedius sensíveis à meticilina foi 0.5-1 μg/mL e o MPC foi entre 16 e 32 μg/mL. O MIC das onze cepas de S. pseudintermedius resistentes à meticilina variou de 0.5 a 2 μg/mL com o MPC variando entre 16 e 32 μg/mL. Um único isolado de S. aureus multirresistente (MRSA) apresentou um MIC de 1 μg/mL e MPC de 16 μg/mL. Não foi observada inibição do crescimento nas concentrações testadas para os isolados bacterianos E. coli, P. aeruginosa e E. faecalis. CONCLUSÃO E IMPORTÂNCIA CLÍNICA: A oxiclozanida apresentou atividade antibacteriana in vitro contra S. pseudintermedius resistente à meticilina. Mais estudos são necessários para avaliar o uso potencial da oxiclozanida como um agente bactericida tópico.

This study was designed to evaluate the ability of MALDI Biotyper (MBT) compared with Vitek™ 2 compact system for accurate identification of Staphylococcus aureus (S. aureus) and coagulase-negative staphylococci (CNS) strains and discriminate methicillin-sensitive S. aureus (MSSA) from methicillin-resistant S. aureus (MRSA). Throughout Al-Qassim region, Saudi Arabia, a total of 198 isolates of S. aureus (132 MSSA and 66 MRSA) and 44 CNS were collected from five dairy farms where the prevalence of staphylococcal mastitis was reported. The results produced by Vitek™ 2 compact system demonstrated that 123/132 MSSA isolates (93.18%), 61/66 MRSA (92.42%), and 37/44 CNS species (84.09%) were correctly identified. However; 130/132 MSSA (98.48%), 64/66 MRSA (96.96%), and 44/44 CNS (100%) were correctly identified by MBT with score ≥2. 00. The principal component analysis (PCA) dendrogram generated by MBT illustrated that the tested isolates were classified into two groups of Staphylococcus species at the distance level of 600. S. aureus isolates were found to be closely related with higher peak intensities in the mass of 3,993 Da, 4,121 Da and 5,845 Da were detected in MRSA, whereas, that were lost in MSSA. Conclusion: This study verified that MBT is an alternative powerful tool for precise identification and discrimination of Staphylococcus species.

This study was conducted to ascertain the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in marine finfish (Argyrosomus japonicus) harvested from the wild and two re-circulatory aquaculture systems, and evaluating the reliability of three phenotypic methods in the detection of methicillin resistance. A total of 120 dusky kob fish were sampled for S. aureus detection using conventional methods and confirmed by polymerase chain reaction (PCR) targeting the nuc gene. Methicillin resistance was determined by molecular detection of the mecA gene. Using mecA as the defining standard, the specificities and sensitivities of cefoxitin disc diffusion, oxacillin screen agar, and growth of S. aureus on Brilliance MRSA II Agar were evaluated. A total of 321 presumptive S. aureus isolates were recovered by culture, out of which 202 (62.9%) were confirmed by PCR. Of these, 33 (16.3%) strains were mecA positive while 169 (83.7%) were mecA negative. The sensitivities and specificities of MRSA detection was 93.9 and 91.7%, 81.8 and 92.3%, and 87.9 and 94.1% for cefoxitin disc, oxacillin screen agar test, and Brilliance MRSA II agar, respectively. This is so far the first report of MRSA in dusky kob aquaculture in South Africa. In the absence of molecular techniques, cefoxitin disc diffusion test is recommended along with any other phenotypic method to improve MRSA detection from samples of veterinary origin. Practical implications Methicillin-resistant Staphylococcus aureus currently presents one of the greatest challenges for medical research worldwide, as well as is one of the most important causes of bacteria gastroenteritis due to preformed toxins in foods. There is a dearth of knowledge on marine foods as carriers/sources of MRSA infection. There are also major discrepancies obtained with MRSA detection methods, making effective detection of this pathogen complicated. The results from this study show that healthy aquaculture fish are reservoirs of MRSA, thus it is necessary to regularly monitor marine foods. Cefoxitin disc diffusion test is recommended as the preferred method for detection of MRSA from fish/food samples where molecular methods are lacking.

Summary Reasons for performing study Staphylococcus intermedius group (SIG) bacteria can colonise the nares of some animals but are also emerging pathogens in humans and animals. Objectives To analyse SIG nasal carriage in healthy donkeys destined for food consumption in Tunisia and to characterise recovered isolates. Methods Nasal swabs from 100 healthy donkeys were tested for SIG recovery, and isolates were identified by biochemical and molecular methods. Antimicrobial susceptibility of isolates was tested and detection of antimicrobial resistance and virulence genes was performed. Isolates were typed at the clonal level by multilocus sequence typing and SmaI pulsed-field gel electrophoresis. Results Staphylococcus delphini and Staphylococcus pseudintermedius (included in SIG) were obtained in 19% and 2% of the tested samples, respectively, and one isolate per sample was characterised. All isolates were meticillin susceptible and mecA negative. Most S. delphini and S. pseudintermedius isolates showed susceptibility to all antimicrobials tested, with the exception of 2 isolates resistant to tetracycline (tet(M) gene) or fusidic acid. The following toxin genes were identified (percentage of isolates): lukS-I (100%), lukF-I (9.5%), siet (100%), se-int (90%), seccanine (19%) and expA (9.5%). Thirteen different pulsed-field gel electrophoresis profiles were identified among the 21 SIG isolates. Additionally, the following 9 different sequence types (STs) were detected by multilocus sequence typing, 6 of them new: ST219 (6 isolates), ST12 (5 isolates), ST220 (3 isolates), ST13, ST50, ST193, ST196, ST218 and ST221 (one isolate each). Conclusions Staphylococcus delphini and S. pseudintermedius are common nasal colonisers of donkeys, generally susceptible to the antimicrobials tested; nevertheless, these SIG isolates contain virulence genes, including the recently described exfoliative gene (expA) and several enterotoxin genes, with potential implications for public health. This is the first description of S. delphini in Tunisia. The Summary is available in Chinese – see Supporting information.

Objectives To determine the prevalence of selected coagulase-positive methicillin-resistant Staphylococcus aureus (MRS) in the conjunctival sac in a group of healthy dogs and to compare the prevalence of ocular MRS colonization with colonization of typically assessed body sites including the nasal cavity and rectum. Animals studied 123 healthy dogs were used in the prevalence study: 40 dogs from a shelter and 83 privately owned dogs. Procedures The sampling procedure included culturing three separate sites per subject in the following order: the lower conjunctival fornices, the nares, and rectum. Results A low prevalence of 1.6% (2/123) of MRS was detected in healthy dogs. Methicillin-resistant Staphylococcus pseudintermedius was isolated from two dogs, one from a conjunctival swab and the other from a rectal swab. Conclusion The survey data indicate the ocular surface is a potential site of MRS colonization, although the prevalence was low in healthy dogs.

The prevalence of the methicillin-resistant Staphylococcus aureus (MRSA) among conventional pig herds in the Netherlands is high (around 71%). Nevertheless, information about the prevalence of MRSA among organic pig herds is lacking. Here, we report a study on 24 of the 49 organic pig herds in the Netherlands. The prevalence of MRSA positive herds showed to be 21%. The genetic characteristics of the MRSA isolates were similar to MRSA CC398 described in conventional pigs except one exceptional HA-MRSA CC30 found in one herd, which was presumably caused by human to animal transmission. This resulted in a prevalence of MRSA CC398 in the organic herds of 16.7%.

Summary Objectives The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients in the United States is approximately 25%. Little is known about the relative proportion of hospital- versus community-associated strains or the antimicrobial susceptibility of MRSA in different CF centers. We hypothesized that the majority of MRSA isolates obtained from children with CF are those endemic in the hospital and that those associated with community acquisition (SCCmec IV) would be more resistant than typically seen in non-CF MRSA isolates. Methods We studied MRSA strains from seven pediatric CF centers to determine the clonal distribution based on DNA sequencing of the staphylococcal protein A gene (spa typing), the type of staphylococcal chromosomal cassette mec (SCCmec), and the proportion of strains with Panton-Valentine leukocidin (PVL). Antimicrobial susceptibility to systemic and topical antibiotics was compared between different MRSA types. Results We analyzed 277 MRSA isolates from unique patients (mean age 11.15 ± 4.77 years, 55% male). Seventy % of isolates were SCCmec II PVL negative and the remainder SCCmec IV. Overall 17% MRSA strains were PVL positive (all SCCmec IV). Spa typing of 118 isolates showed most of the SCCmec II strains being t002, while SCCmec IV PVL positive isolates were t008, and SCCmec IV PVL negative isolates represented a variety of spa-types. The proportions of SCCmec II strains and spa-types were similar among centers. Overall rates of resistance to trimethoprim–sulfamethoxazole (4%), tetracycline (7%), tigecycline (0.4%), linezolid (0.4%) as well as fosfomycin (0.4%), fusidic acid (3%), and mupirocin (1%) were low. No strains were resistant to vancomycin. SCCmec II strains had higher rates of resistance to ciprofloxacin and clindamycin (P

Objective To determine the methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) contamination rate of white coats (WC) and surgical scrubs (SS) worn by personnel at the Ontario Veterinary College Health Sciences Centre (OVCHSC) and to identify risk factors associated with clothing contamination. Study Design Cross-sectional study. Sample Population Personnel including clinical faculty, house officers, technicians, and veterinary students working at the OVCHSC. Methods Electrostatic cloths were used to sample WC and SS of hospital personnel. Samples were tested for MRSA and MRSP and isolates were typed. Participants completed a self-administered questionnaire and data was evaluated for risk factors. Results Of 114 specimens, MRS were isolated from 20 (17.5%), MRSA from 4 (3.5%), and MRSP from 16 (14.0%). Technicians were 9.5× (OR = 0.95, 95% CI: 1.2–∞, P = .03) more likely than students to have clothing contaminated with MRSA. No risk factors were identified for MRSP or for overall MRS contamination. Conclusions Standard hospital clothing was found to have a high prevalence of MRS contamination in a veterinary teaching hospital and could be a source of hospital-acquired infections.

The aim of this study was to determine the prevalence of enterotoxigenic and methicillin-resistant Staphylococcus aureus in ice creams. After culture-based identification of isolates, the presence of 16S rRNA and nuc was confirmed by mPCR. S. aureus was identified in 18 of 56 fruity (32.1%), 4 of 32 vanilla (12.5%), and 1 of 12 chocolate (8.3%) ice creams. S. aureus was identified as 38 isolates in 23 ice cream samples by culture-based techniques, but only 35 isolates were confirmed by PCR as S. aureus. To determine the enterotoxigenic properties of PCR-confirmed S. aureus isolates, a toxin detection kit was used (SET RPLA®). Of the 12 enterotoxigenic S. aureus isolates, 9 SEB (75%), 1 SED (8.3%), 1 SEB+SED (8.3%), and 1 SEA+SEB+SED (8.3%) expressing isolates were found. The presence of enterotoxin genes (sea, seb, sed) was identified in 13 (37.1%) out of 35 isolates by the mPCR technique. In the ice cream isolates, the sea, seb, and sed genes were detected: 1 sea (7.6%), 9 seb (69.2%), 1 sed (7.6%), 1 seb+sed (7.6%), and 1 sea+seb+sed (7.6%), respectively. The sec gene was not detected in any of these isolates. One of the 35 (2.8%) S. aureus strain was mecA positive.

During the last few years, methicillin-resistant Staphylococcus aureus (MRSA) ST398 has been isolated frequently from livestock, especially from pigs and to a lesser extent from cattle and poultry. To gain insight into the distribution of this bacterium in pig farms versus multispecies farms, 30 Belgian farms (10 pig, 10 pig/poultry and 10 pig/cattle farms) were screened for the presence of MRSA. On each farm, 10 nasal swabs were taken from pigs. When present, cattle (n = 10) were sampled in the nares and poultry (n = 10) in the nares, earlobes and cloaca. A selection of the obtained isolates were further characterized using multilocus sequence typing (MLST), spa typing, SCCmec typing, pulsed field gel electrophoresis (PFGE), multiple-locus variable-number tandem repeat analysis (MLVA) and antimicrobial susceptibility testing. On 26 of 30 farms, MRSA was isolated from pigs. Furthermore, MRSA was also isolated from poultry and cattle on one pig/poultry and five pig/cattle farms, respectively. All tested MRSA isolates belonged to ST398. Eight spa types (t011, t034, t567, t571, t1451, t2974, t3423 and t5943) were detected, among which t011 predominated. SCCmec cassettes type IVa and V were present in 20% and 72% of the isolates, respectively. When combining the results of the two remaining typing methods, PFGE and MLVA, eighteen genotypes were obtained of which one genotype predominated (56% of the positive farms). All MRSA isolates were resistant to tetracycline. Resistance to trimethoprim, aminoglycosides, macrolides, lincosamides, fluoroquinolones and chloramphenicol was also observed. In conclusion, there was no effect of the farm type on the MRSA status of the pigs. A statistically significant difference was observed when comparing the pig/poultry or the pig/cattle MRSA status on the multispecies farms. Additionally, a wide variety of MRSA ST398 strains was found within certain farms when combining different typing methods.

This study explores the characteristics of Staphylococcus aureus (S. aureus) in swine and their human handlers in a convenience sample of 35 farms in Connecticut. Husbandry practices are clearly different from better-known concentrated animal feeding operations (CAFOs) with less intensive rearing conditions. Nasal samples were collected from 263 pigs and nine humans on 35 farms during the 2010 rearing season. Samples were analysed using established microbiology methods, and resulting methicillin-sensitive (MSSA) and resistant (MRSA) isolates were typed by pulsed-field gel electrophoresis (PFGE) and spa typing. PCR was used to detect the presence of the Panton-Valentine Leukocidin (PVL) gene, a cytotoxin usually associated with CA-MRSA infection. A farm assessment form and questionnaire were used to obtain the information about husbandry practices and human exposure risk, respectively. Staphylococcus aureus colonized swine and humans were found in 51% (18/35) of the farms sampled at a rate of 30% (85/259) and 22% (2/9), respectively. Eight pigs and two humans were MRSA positive on five farms. MRSA in swine was related to healthcare-associated (HA), community-associated (CA) or livestock-associated (LA) MRSA strains, whereas humans were colonized with HA-MRSA. On the basis of spa typing, there was evidence of human-animal transmission thereby signifying humanosis/reverse zoonoses. The PVL gene was found in 88% (7/8) of MRSA swine isolates, the first time this gene has been seen in colonized pigs sampled on US farm. MSSA isolates belonged to six spa types: t337 (41%), t034 (12%), t334 (12%), t4529 (12%), t8760 (18%) and t1166 (6%) including LA strains. This is the first time spa type t8760 has been reported and the only MSSA with the PVL gene. In summary, MRSA including LA strains (LA-MRSA) can be found on small farms with different husbandry practices from CAFOs, suggesting that preventive measures for zoonotic MRSA infection should address a range of animal production.

This study describes the isolation and characterization of methicillin-resistant Staphylococcus aureus (MRSA) from slaughtered pigs sampled from local markets in Hong Kong. The nares of 400 slaughtered pigs were cultured and MRSA isolates characterized for the presence of antibiotic-resistance determinants, toxins and SCCmec and spa types using PCR. Clonality was investigated using PFGE and MLST. The prevalence of MRSA colonization of slaughter pigs was 39.3%, the majority (92%) harbouring SCCmec type IVb. Of the 157 samples yielding MRSA, 13 had two distinct MRSA strains present. Spa type t899 was predominant, with only 5/170 isolates displaying closely related types (t4474, t1939, t2922 and t5390). PFGE with sma1 and MLST confirmed the strains as ST9. Most isolates were multidrug resistant. Tetracycline resistance (97%) was mainly attributable to tet(K) with only 3% of isolates additionally harbouring tet(M). Resistance to erythromycin (89%) and chloramphenicol (71%) was associated with the presence of erm(C), and fex(A), respectively. No strains carried cfr and there was no resistance to linezolid, although minimum inhibitory concentration (MICs) were close to the resistance break point. Resistance to clindamycin (99%), ciprofloxacin(78%), quinopristin-dalfopristin (44%) and cotrimoxazole (32%) was common, but remained low for fusidic acid (4%) and rifampicin (2%). All strains were negative for PVL, exfoliative, and enterotoxins. This survey confirmed the uniformity of MRSA isolates in pigs from several regions of China, in contrast to more diversified characteristics reported in European studies. Colonization rates were higher than previously reported. Isolates were resistant to a wide range of antibiotics, but resistance was not detected to linezolid, nitrofurantoin, vancomycin or tigecycline. Although the clinical importance of ST9 in humans is uncertain, continued surveillance, in particular of those occupationally-exposed, is recommended.

Background/Objectives: Antibiotic resistance in the community, including transfer between bacteria, is a growing concern for clinicians. Acne is commonly treated in general practice, sometimes with antibiotics. The aim of this study is to measure the rate of carriage of antibiotic resistant Propionibacterium acnes 10 years apart in general practice and the relationship of resistance to type of treatment, as well potential effects on other flora. Methods: Patients (N = 215) with acne presenting to Australian Capital Territory and south-eastern New South Wales general practices were swabbed for P. acnes in 1997–1998 and 2007. Clinical details were collected with questionnaires. In 2007 swabs were also taken for Staphylococcus aureus and Streptococcus pneumoniae. GP's diagnostic classification of acne was tested using a set of standard photographs. Results: Resistant P. acnes was isolated from 20 patients (9%) and the proportion that was resistant was the same in 1997–1998 and in 2007. Antibiotic use, particularly topical, was associated with P. acnes resistance. Resistance rates declined with the time elapsed since ceasing antibiotics. Use of retinoids was associated with a decreased chance of growing P. acnes (P = 0.008) but not with decreased resistance. Simultaneous resistance with S. aureus was not detected, but only in 30 patients was S. aureus isolated. Conclusions: P. acnes resistance was similar in 1997–1998 and in 2007.The chance of a patient carrying a resistant strain of P. acnes is significantly greater with recent exposure to antibiotics, and clinicians should limit prescribing where possible. Resistance disappears rapidly after ceasing antibiotics. Cross resistance with other organisms was not detected in this study.

Bacteria in the genus Staphylococcus are the most common pathogens associated with nosocomial and community-onset skin and soft tissue infections (SSTI), of both humans and animals, world-wide (Werkenthin et al., 2001; Diederen et al., 2006). An increase in the prevalence of methicillin-resistance (MR) in Staphylococcus aureus isolates (MRSA) over the past four decades has led to higher morbidity, mortality, and hospital expenditures associated with S. aureus infections of people (Cosgrove et al., 2005). It is known that persons who live in close contact with MRSA patients can also become colonized, and that colonization may then persist for months to years (Marschall et al., 2006; Vriens et al., 2005). Colonized people may also serve as a source of MRSA spread to susceptible individuals (Calfee et al, 2003; Johansson et al., 2007; Huijsdens et al., 2006). Although S. aureus is not the primary staphylococcal species that causes SSTIs of dogs and cats, the current scientific literature demonstrates that domestic pets can carry or be infected by the same epidemic strains of MRSA that cause SSTI of people (Weese et al, 2006; Loeffler et al., 2010). Recommended protocols for prevention of recurrent MRSA infections of people do address pet colonization, but the supporting risk assessments are based on limited reports such as small case series and anecdotal descriptions (CLSI 2010). Additional objective data to help quantify and subsequently mitigate the risk of human-animal cross-transmission would be valuable to health care providers and public health professionals. The objectives of this study were to test the primary hypothesis that infected people can cross-transmit MRSA to domestic pets (dogs and cats) with which they live in close contact, and to identify risk factors associated with this cross-transmission. It was also hypothesized that the proximity of a pet to a person with MRSA infection (defined as “close” versus “casual” contact) would be the primary risk factor associated with pet carriage of MRSA.

Methicillin-resistant Staphylococcus aureus (MRSA) have been reported in commercially raised pigs and their human handlers, raising concerns of zoonotic transmission. To determine whether MRSA in backyard-raised pigs is commonly transmitted to their human owners, a matched study of this type of pigs and their owners was conducted in selected counties in Michigan. Nasal swabs from matched owner-pig pairs (n = 50 pairs) with a few unmatched pig (n = 3) and human (n = 4) samples were collected and processed using standard isolation and identification protocols. No matched owner-pig pair was found; however, MRSA was isolated from 1/54 (1.9%) human samples and 2/53(3.8%) of the pigs. The single human isolate was not strain type USA100-1100 by pulsed-field gel electrophoresis (PFGE), was sequence type (ST) 8 by multilocus sequence typing (MLST), possessed SCCmec type IVb and agr I and was negative for the Panton-Valentine leukocidin (PVL) toxin gene. The two pig isolates were indistinguishable by PFGE (not USA100-1100), and both isolates were ST5 by MLST, possessed SCCmec type III and agr II and were negative for the PVL gene. Persons raising backyard swine from the selected Michigan counties had MRSA carriage rates similar to that of the general US population, suggesting that their avocational pig exposure did not increase their risk of MRSA.

Chronic dermatoses are risk factors for Staphylococcus aureus colonization; little is known about the significance of transmission between persons with chronic dermatoses (CD) and their contacts. We collected nasal, axillary, and skin swabs for S. aureus from 50 attendees of a camp for children with CD and their families at three time points: start and end of 2005 camp and start of 2006 camp (times A, B, and C, respectively). Thirty-one persons had CD, including epidermolysis bullosa (n = 14), atopic dermatitis (n = 7), ichthyosis (n = 5), and psoriasis (n = 5). Methicillin susceptibility and genotype were determined for all S. aureus isolates. Seventy-one unique S. aureus isolate from 10 clonal complexes (CC) were isolated; 14 (20%) were methicillin-resistant (MRSA). Persons with CD were more likely than those without CD to be colonized with S. aureus at the start of the 2005 (p = 0.01) and 2006 (p = 0.02) camp or at any time or site (p = 0.04) or to be persistently colonized with the same S. aureus CC at the start and end of the 2005 camp. Persons with atopic dermatitis had the highest burden of S. aureus colonization, whereas MRSA was isolated most frequently from attendees with epidermolysis bullosa. Three hospitalizations for skin infections were noted in people with CD between the 2005 and 2006 camps, versus three hospitalizations in the 6 months before the 2005 camp. Although S. aureus colonization was frequent among camp attendees (and in persons with CD in particular), it was diverse and variable. Camp attendance did not appear to affect infection-related clinical outcomes.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen and recent evidence has implicated food animals in the epidemiology of human infections in some regions. While the role of food in MRSA transmission and human health relevance are unclear, MRSA can be found in retail meat products internationally, including beef, yet there has been minimal investigation of MRSA in beef cattle. This study involved screening feedlot cattle for nasal and gastrointestinal colonization with MRSA shortly before the time of slaughter. Methicillin-resistant S. aureus was not isolated from any of 491 nasal swabs and 488 faecal samples. This finding is in contrast to studies that have isolated MRSA from retail beef in Canada, performed in the same laboratory using comparable culture techniques. The reason for this discrepancy is unclear but it demonstrates that further study of MRSA in livestock as well as slaughter, processing and retail environments is needed to elucidate the epidemiology of MRSA contamination of meat.

The main aim of the study was to examine if hospital-associated clones of multidrug-resistant Staphylococcus epidermidis (MDRSE), commonly identified in hospitals in our region, also are spread amo ...

Summary Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is increasingly reported in small animals and cases of human infections have already been described despite its recent emergence in veterinary practice. We investigated the prevalence of MRSP and methicillin-resistant Staphylococcus aureus (MRSA) among small animal dermatologists attending a national veterinary conference in Italy. Nasal swabs were obtained from 128 veterinarians, seven of which harboured MRSP (n = 5; 3.9%) or MRSA (n = 2; 1.6%). A follow-up study of two carriers revealed that MRSP persisted for at least 1 month in the nasal cavity. Methicillin-susceptible S. aureus (MSSA) was isolated from 32 (25%) conference participants, whereas methicillin-susceptible S. pseudintermedius (MSSP) was not detected, suggesting that MRSP may have a particular ability to colonize humans compared to MSSP. All isolates were characterized by spa typing. Methicillin-resistant isolates were further typed by antimicrobial susceptibility testing, SCCmec and multi-locus sequence typing. Two lineages previously associated with pets were identified among the five MRSP isolates; the European epidemic clone ST71-SCCmec II-III and ST106-SCCmec IV. One of the two MRSA isolates displayed a genotype (ST22- SCCmecIV) frequently reported in dogs and cats. MRSP isolates were resistant to more antimicrobial agents compared with MRSA isolates and displayed the typical multidrug resistance patterns of MRSP in pets. The 32 MSSA isolates belonged to 20 spa types and the most frequent types (t12, t15 and t166) were associated with common S. aureus lineages in humans (CC30 and CC45). Although low, the 3.9% MRSP carriage rate found among small animal dermatologists was surprising in consideration of the rare occurrence of S. pseudintermedius in humans, the lack of MSSP detection and the recent appearance of MRSP in Europe. As cases of human MRSP infection have been linked with pets, veterinarians should be aware of this zoonotic risk and proper preventative measures should be taken to avoid MRSP transmission from animal patients.

Elevated rates of methicillin-resistant Staphylococcus aureus (MRSA) carriage have been reported in veterinary personnel, suggesting an occupational colonization risk. Hong Kong veterinary personnel (n = 150) were sampled for coagulase-positive staphylococci (CPS) nasal colonization. Risk factors for colonization were assessed by questionnaire. Isolates were identified and antibiotic susceptibility determined. All CPS isolates were investigated for mecA carriage, SCCmec type and PVL genes. Two subjects were colonized with methicillin-resistant CPS: one with MRSA (spa type t002 (CC5), SCCmec type II) and one with methicillin-resistant Staphylococcus pseudintermedius (MRSP) (MLST type ST71, SCCmec type II-III). MLST type ST71 S. pseudintermedius strain is the predominant MRSP clone circulating in dogs in Europe and in Hong Kong. The low MR-CPS colonization rate may be associated with low levels of large animal exposure or low rates of MRSA colonization of companion animals in Hong Kong. Colonization with non-aureus CPS, which may cause human infection, must also be considered in veterinary personnel.

Antimicrobials effective against meticillin-resistant staphylococci are limited. Mupirocin is a topical antimicrobial used to treat bacterial skin infections. Novobiocin is an oral antimicrobial approved for treatment of staphylococcal upper respiratory infections in dogs. This study reports the in vitro activity of mupirocin and novobiocin on meticillin-susceptible (MSS) and resistant staphylococci (MRS) from healthy dogs and dogs with superficial pyoderma. Staphylococci were isolated from skin swabs at four sites on healthy dogs and from lesions on dogs with superficial pyoderma. Staphylococci were identified by morphology and by catalase and coagulase testing. Speciation and susceptibility testing were performed by the Dade Microscan (W. Sacramento, CA, USA). Meticillin resistance was confirmed by an oxacillin screen plate. Novobiocin and mupirocin susceptibilities were tested by disc diffusion. Staphylococci were cultured from 61 healthy dogs (17 MRS and 44 MSS) and 30 dogs with pyoderma (15 MRS and 15 MSS), with higher proportions of MRS isolates in dogs with pyoderma (P=0.038; χ(2) test). For mupirocin, 79.5% (35 of 44) MSS and 82.3% (14 of 17) MRS isolates from healthy dogs, and 100% (15 of 15) MSS and 86.6% (13 of 15) MRS isolates from dogs with pyoderma were susceptible (MSS, P=0.094; MRS, P=1.0; Fisher's exact test). For novobiocin, 95.4% (42 of 44) MSS and 52.9% (nine of 17) MRS isolates from healthy dogs and 93.3% (14 of 15) MSS and 80% (12 of 15) MRS isolates from dogs with pyoderma were susceptible (MSS, P=1.0; MRS, P=0.148; Fisher's exact test).

Using different typing methods (MLST, spa-, SCCmec- and agr-typing), PFGE and DNA microarray-based chip analysis, we characterized 20 MRSA strains isolated from livestock and veterinarians. PFGE analysis after macrorestriction with EagI provided seven different band patterns, which could be grouped into four clusters. One cluster consisted of all MRSA ST398 strains isolated from pigs, calves, mastitis milk and two veterinarians. One strain of ST398 from a veterinarian and the two strains of ST1 and ST8 formed the three other clusters. Antimicrobial susceptibility testing showed that 15 of 20 strains were resistant to ampicillin, cefoxitin, clindamycin, erythromycin, oxacillin, penicillin and tetracycline. All strains were susceptible to rifampin and vancomycin, 19 were susceptible to ciprofloxacin and 18 were susceptible to sulphamethoxazole/trimethoprim. Genes encoding different enterotoxins, leukotoxins and haemolysins were found in certain strains.

OBJECTIVE: To assess the current bacteriology and the incidence of methicillin-resistant Staphylococcus aureus in orbital and subperiosteal abscesses of paranasal sinus disease origin. STUDY DESIGN: Case series with chart review. SETTING: An otolaryngology and ophthalmology specialty hospital. SUBJECTS AND METHODS: Fifty-three patients were treated between 1994 and 2008 for orbital or subperiosteal abscess and paranasal sinusitis, confirmed by imaging and surgical intervention; 46 had operative culture specimens and comprise the study cohort. RESULTS: The mean patient age was 28 years; one third were younger than 18. Nearly twice as many patients had subperiosteal (n 30) as had orbital abscesses (n 16). In 12 patients (26%), cultures were negative or grew only skin flora contaminants (coagulase-negative staphylococci, diphtheroids, and Propionibacterium acnes). Fifteen patients (33%) grew more than one pathogen. Streptococci were isolated in 17 of the 46 cases (37%), S. aureus in 13 (28.3%), gram-negative bacilli in eight (17.4%), and anaerobes in nine (19.6%). Methicillin-resistant S. aureus accounted for three (23.1%) of the S. aureus isolates and 6.5 percent of the total cases. CONCLUSION: Abscess cultures grew a mixture of bacteria, including gram-positive cocci, gram-negative bacilli, and anaerobes. Although streptococci were the most common genus of bacteria isolated, S. aureus was the single most common pathogen recovered and one fourth of these cases were methicillin-resistant S. aureus. Given the significant morbidity that may result from inadequate treatment, an antibiotic active against methicillin-resistant S. aureus should be included in the initial broad-spectrum antimicrobial treatment regimen of orbital and subperiosteal abscesses of sinusitis origin until culture results are available.

The objective of this study was to analyse the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in three dairy herds in the southwest of Germany that had experienced individual cases of clinical and subclinical mastitis associated with MRSA. The herds were identified by the detection of MRSA during routine resistance testing of mastitis pathogens. All quarters of all cows in the herds that were positive on California Mastitis Test were sampled for bacteriological analysis on two occasions. Bulk tank milk samples were also tested. Furthermore, nasal swabs were collected from people working on the farms and from cattle. Environmental samples were collected from associated pig holdings. Isolates were characterized using spa-typing and testing for antimicrobial resistance. Our results revealed a substantial spread of MRSA in the three dairy herds. In the first of the two investigations carried out on all cows in the three herds, milk samples of 5.1-16.7% of dairy cows were found positive for MRSA. The respective proportions in the second herd level investigation were 1.4-10.0%. Quarters harbouring MRSA had higher somatic cell counts than quarters that were negative on culture. Methicillin-resistant Staphylococcus aureus were also detected in nasal swabs of staff (7/9), cows (7/15) and calves (4/7), bulk tank milk samples (3/3) and environmental samples from pig premises (4/5) on the farm. Herds B and C had no contact to herd A. However, in all three herds MRSA of spa-type t011 were detected in milk samples. Results show that MRSA of spa-type t011 is a problem in dairy farms that needs urgent attention.

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important public health concern and pigs have been implicated in human infections. Cross-sectional studies have demonstrated that MRSA can be commonly found in pigs internationally, but little is known about age-related changes in MRSA colonization. This study evaluated MRSA colonization in piglets in a longitudinal manner. Serial nasal swabs were collected from piglets born to 10 healthy sows. The prevalence of MRSA colonization on days 1, 3, 7, 14 and 21 was 1% (1/100), 6.2% (3/97), 8.5% (8/94), 4.4% (4/91) and 20% (18/91) respectively, with an overall pre-weaning prevalence of 34.5%. The prevalence on days 28, 42, 56 and 70 was 34% (31/91), 65% (57/88), 50% (44/88) and 42% (36/87) respectively, with an overall post-weaning prevalence of 85%. Eighty-four percent of piglets from negative sows and 100% of piglets from positive sows that survived at least until the time of weaning were colonized with MRSA at one or more times during the study. There was a significant association between sow and piglet colonization. The age of the piglet was significantly associated with the probability of colonization. No piglets or sows received antimicrobials during the study period. These results indicate that age must be considered when designing surveillance programmes and interpreting results of different studies on MRSA.

Aim: Staphylococcus aureus is an important cause of serious illness in children. Antibiotic resistance is an international problem and affects initial antibiotic choice. We aimed to describe susceptibility patterns of S. aureus isolates from Australian children to inform optimal empiric treatment of staphylococcal infections in this population. Methods: We analysed susceptibility data for all S. aureus isolates from children at Australian tertiary paediatric hospitals in 2006. Susceptibility rates were compared between hospitals and states, and with published studies of S. aureus isolates from Australian adults. Results: Overall, the proportion of methicillin- resistant S. aureus (MRSA) in Australian children was low (9.8%), and in each state it was less than for the comparable adult population. There were significant differences in susceptibility patterns between different states. Most MRSA isolates were susceptible to clindamycin (73%) and all isolates were reported as susceptible to vancomycin. Susceptibility patterns for isolates from bacteraemic patients were similar to those for isolates from all patients. Conclusions: These data support current Australian recommendations for the use of flucloxacillin or a first-generation cephalosporin as initial treatment of non-life-threatening staphylococcal infections. However, broad spectrum antibiotic therapy including agents that are effective against MRSA should be considered for more serious infections. Appropriate specimens should be collected for susceptibility testing to enable directed treatment for MRSA and other resistant organisms. This study highlights the importance of using local, age-specific data in planning antibiotic treatment guidelines, as results vary substantially from city to city and between adults and children. © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Background Antimicrobial-resistant bacteria are increasingly isolated from veterinary patients. Objectives To determine risk factors for antimicrobial resistance (AMR) among canine mucosal staphylococci following routine antimicrobial treatment with cefalexin (CFX), clavulanate-amoxicillin (AC), cefovecin (CVN), clindamycin (CD) or a fluoroquinolone (FQ). Animals Mucosal swab samples (n = 463) were collected from 127 dogs pre-treatment, immediately, and at one- and three-months post-treatment. Methods Staphylococci were identified phenotypically and biochemically as coagulase negative (CoNS) or coagulase positive (CoPS); CoPS were speciated by nuc gene PCR. Antimicrobial susceptibility was determined using disc diffusion and mecA gene carriage by PCR. Multilevel, multivariable models examined associations between risk factors and presence/absence of CoPS, meticillin resistance (MR), multidrug-resistance (MDR) and fluoroquinolone resistance (FQR). Results The percentage of samples with CoNS increased and with CoPS (including S. pseudintermedius) decreased immediately post-treatment with CFX, CVN and CD (P ≤ 0.001) and one month post-treatment with CD (P = 0.003). By three months post-treatment, there was no significant difference compared to pre-treatment samples. Immediately post-treatment with FQs there was significantly increased risk of isolating MRS (P = 0.002), MDR (P = 0.002) or FQR (P = 0.013) staphylococci and of MDR following CFX treatment (P = 0.019). The percentage of samples with AMR staphylococci declined from immediately to three months post-treatment and there was no significant difference between resistance prevalence at one or three months post-treatment for most AMR traits and treatment groups. Exceptions include increased MDR following FQ (P = 0.048) or CFX (P = 0.021), at one and three months post-treatment, respectively. Conclusions and clinical importance Systemic antimicrobials impact on mucosal staphylococci. Immediately after therapy, the mucosa may be a reservoir for AMR staphylococci that are a source of mobile genetic elements carrying AMR genes.

Community-acquired, methicillin-resistant Staphylococcus aureus (CA-MRSA) has been associated with morbidity and mortality in various countries. In this study, we characterized the molecular and clinical features of pediatric CA-MRSA pneumonia in China. Between June 2006 and February 2008, 55 previously healthy children confined in eight hospitals countrywide were found to be afflicted with CA-MRSA pneumonia. A total of 55 strains collected from these children were analyzed by multilocus sequence typing (MLST), Staphylococcus cassette chromosome mec (SCCmec) typing, and spa typing. The Panton-Valentine leukocidin (PVL) gene was also detected. Overall, nine STs were obtained, with ST59 (40.4%) established to be the most prevalent type. We first registered the new ST1409 from a child with necrotizing pneumonia. SCCmecIVa was the most predominant type, followed by SCCmec type V. Twelve spa types were identified, of which one new spa type, t5348, was first detected and registered. One typical livestock-associated spa type, t034, was found in a 4-month-old girl living in the countryside. We also found that 40% of those isolates were PVL-positive. In addition, the median age of the children in this study was 10 months. A total of 69% (38/55) of the children with community-acquired pneumonia (CAP) had preceding influenza or influenza-like illness, and three ST910-MRSA-IV strains (PVL gene-positive) were associated with severe necrosis. The results indicated that the recent CA-MRSA found in Chinese children with CAP was largely associated with the spread of the ST59-MRSA-IV clone, and most of the PVL-positive strains in this study did not cause necrotic cases.

Oral Diseases (2010) 16, 465–468 Objectives: The oral cavity may represent a site of colonization by antibiotic-resistant bacteria, such as methicillin-resistant staphylococci (MRS). To define the prevalence of staphylococci and MRS in the oral cavity, an observational study was carried out in the city of Bari (Italy). Methods: Sixty subjects were asked to provide oral samples and a questionnaire about risk factors of colonization by MRS. An enrichment medium specific for staphylococci was used for the isolation. Results: Swabs and corresponding questionnaires were available from 36 out of 60 patients. Staphylococci were isolated from seven out of 36 samples (prevalence 19.4%). Among the seven staphylococcal isolates, three were Staphylococcus aureus, and one strain, belonging to S. epidermidis species, was found to be MR (1.7%). No methicillin-resistant S. aureus were isolated. Five out of seven staphylococcal isolates exhibited resistance to more than two classes of non-beta-lactams antimicrobials. None of the risk factors analysed correlated with the status of MRS carriers, except the presence of oral disease. Conclusions: The results underline the potential role of the oral cavity as a reservoir of staphylococci.

This article presents a qualitative risk assessment of the acquisition of meticillin-resistant Staphylococcus aureus (MRSA) in pet dogs, representing an important first step in the exploration of risk of bidirectional MRSA transfer between dogs and humans. A conceptual model of the seven potential pathways for MRSA acquisition in a dog in any given 24-hour period was developed and the data available to populate that model were considered qualitatively. Humans were found to represent the most important source of MRSA for dogs in both community and veterinary hospital settings. The environment was found to be secondary to humans in terms of importance and other dogs less still. This study highlights some important methodological limitations of a technique that is heavily relied upon for qualitative risk assessments and applies a novel process, the use of relative risk ranking, to enable the generation of a defensible output using a matrix combination approach. Given the limitations of the prescribed methods as applied to the problem under consideration, further validation, or repudiation, of the findings contained herein is called for using a subsequent quantitative assessment.

Background: A higher prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization is reported in healthcare workers compared with nonhealthcare workers. Hypothesis: The prevalence of MRSA colonization differed in people and pets in households with healthcare workers as compared with households without healthcare workers. Subjects: A person and 1 dog or cat from 586 households defined as either a nonhealthcare (n = 213), veterinary healthcare (n = 211), or human healthcare (n = 162) worker household. Methods: Prospective cross-sectional study. Samples from humans and pets were cultured in vitro. Staphylococcus aureus was identified as methicillin sensitive (MSSA) or MRSA with mecA polymerase chain reaction. Pulsed-field gel electrophoresis and spa-typing were used to characterize relatedness of S. aureus and MRSA and assign USA types. Results: The prevalence of MSSA and MRSA in humans was 21.5% (126/586) and 5.63% (33/586), respectively, and 7.85% (46/586) and 3.41% (20/586), respectively, in pets. There were no differences in prevalences of either MSSA or MRSA between household types. The proportion of MRSA among all S. aureus isolates in humans and pets was 20.8% (33/159) and 30.3% (20/66), respectively. In

We analyzed the performance of a selective enrichment broth combined with Taqman-based real-time duplex nuc-mecA-PCR to expedite the screening of methicillin-resistant Staphylococcus aureus (MRSA). We found the broth to be able to select MRSA strains (oxacillin MIC range 4-256 microg/ml) from MSSA strains. A total of 31 MRSA strains were found from 1250 clinical samples screened. The nuc-mecA-PCR was positive from all enrichment broths containing MRSA. From the remaining 1219 samples negative for MRSA on culture/subculture, 138 samples were nuc+/mecA+ in PCR. The sensitivity of the test was 93.5%, specificity 88.6%, positive predictive value 17.3%, and negative predictive value 99.8% as compared to culture. Thus, with this method, the negative MRSA results can be reliably reported within 24-48 h from sampling. The method is a practical additional alternative to those already described for the same purpose.

Three latex agglutination kits for rapid identification of Staphylococcus aureus were compared by testing a selection of isolates, which included methicillin resistant S. aureus, methicillin sensitive S. aureus and a diverse selection of coagulase-negative staphylococci. The sensitivities of Monostaph Plus (Bionor Laboratories, Skien, Norway), Pastorex Plus (Bio-Rad Laboratories, Hercules, CA) and Staphaurex Plus (Oxoid, Cambridge, UK) were 98.5, 98.3 and 98.3% respectively, and the specificities were 97.5, 97.0 and 96.5%, respectively. None of the kits detected Staphylococcus lugdunensis correctly. This evaluation shows that the Monostaph Plus agglutination kit performs well and comparable to Pastorex Staph-Plus and Staphaurex Plus. PRACTICAL APPLICATIONS Latex agglutination kits are very useful in the routine identification of Staphylococcus aureus, but can occasionally give false-positive or false-negative results. Knowledge of how the various available kits are performing is, therefore, very important when selecting a kit for use. Correct identification of S. aureus is important, especially in relation to methicillin-resistant S. aureus, since other staphylococci species are known to carry the methicillin-resistance determinant mecA, but are of less clinical importance. This study is the first study comparing an improved version of the Monstaph-Plus kit with other latex agglutination kits, and provides new data about this kit.

To determine the zoonotic risk from meticillin-resistant staphylococcal species or transfer of resistance genes between dogs with pyoderma and their owners, 25 dog–owner pairs were studied. Cultures were obtained from the dog’s lesions and the owner’s nasal cavity on the initial visit. Staphylococcus isolates were identified and antimicrobial susceptibility tests were performed by the Kirby-Bauer disk diffusion method. Presence of the mecA gene was determined by PCR. Staphylococcal Cassette Chromosome (SCCmec) typing was performed by multiplex PCR. Eighteen dogs had a meticillin-resistant staphylococcal species, with meticillin-resistant S. pseudintermedius (MRSP) isolated from 15 dogs. MRSP was isolated from two owners of dogs with MRSP skin infections. Both organisms had the same susceptibility pattern and SCCmec type. MRSP was not isolated from the owners after treating both dogs for 1 month. At least one coagulase-negative Staphylococcus spp. (CoNS) was isolated from each owner, with meticillin resistance found in 16 (64%) of the isolates. The mecA gene was identified in all but two of the meticillin-resistant Staphylococcus spp. Multiplex PCR identified SCCmec type V in all MRSP. The mecA gene-possessing CoNS isolates from owners contained either SCCmec type IVa or IVc. In conclusion, MRSP colonization of owners appeared to be uncommon and transient. Human nasal carriage of meticillin-resistant CoNS was common, but the SCCmec types were different from those in the canine MRSP isolates. Owners do not appear to be at great risk of zoonotic transfer of organisms or antimicrobial resistance genes from dogs with MRSP infections, but the findings should be confirmed with a much larger cohort. Resume Afin de determiner le risque zoonotique des staphylocoques resistant a la meticilline ou le transfert de genes de resistances entre chiens atteints de pyodermites et leurs proprietaires, 25 paires de chien et leur maitre ont eteetudies. Des cultures ont ete obtenues a partir des lesions du chien et de la cavite nasale de son maitre au cours de la visite initiale. Les isolats de Staphylococcus ont ete identifies et des tests de susceptibilite antimicrobienne ont ete realises par la methode de diffusion sur disque Kirby-Bauer. La presence du gene mecA a ete determinee par PCR. Le typage du SCCmec (Staphylococcal Cassette Chromosome) a ete realise par PCR multiplexe. Dix huit chiens etaient porteurs d’especes de staphylocoques resistant a la meticilline dont 15 etaient des S. pseudointermedius (MRSP). MRSP a ete isole de deux proprietaires de deux chiens atteints d’infection a MRSP. Les deux organismes avaient les memes susceptibilites et type de SCCmec. MRSP n’a plus ete isole des proprietaires apres un mois de traitement des deux chiens. Au moins un Staphylococcus coagulase-positive (CoNS) a ete isole de chaque proprietaire avec une resistance a la meticilline dans 16 (64%) isolats. Le gene mecA a ete identifie dans tous sauf deux des Staphylococcus spp. Resistant a la meticilline. SCCmec type V a ete identifie par PCR multiplex pour tous les MRSP. Les souches CoNS porteurs du gene mecA isolees des proprietaires contenaient SCCmec de type IVa ou IVc. En conclusion, la colonisation des proprietaires par MRSP semble rare et transitoire. Le portage nasal humain de CoNS resistant a la meticilline etait frequent mais les types de SCCmecetaient differents des isolats de MRSP canins. Le transfert d’organismes ou de genes de resistance antimicrobiens de chiens atteins d’infections a MRSP a leur proprietaire n’apparait pas comme un risque majeur zoonotique mais ces resultats devraient etre confirmes par des essais sur un plus grand nombre de chiens. Resumen Para determinar el riesgo zoonotico de las especies de estafilococo resistentes a meticilina o la transferencia de genes de resistencia entre perros con pioderma y sus propietarios, 25 parejas perro-propietario fueron incluidas en este estudio. Los cultivos se obtuvieron de lesiones de perros y de la cavidad nasal de los propietarios en la visita inicial. Se identificaron aislados de Staphylococcus y la susceptibilidad antimicrobiana se evaluo por el metodo de difusion de disco de Kirby-Bauer. Se determino la presencia del gen mecA mediante PCR. El fenotipado del Cassette Cromosomal de estafilococo(SCCmec) se evaluo mediante PCR multiplex. Dieciocho perros tenian especies de estafilococos resistentes a meticilina, siendo S. pseudintermedius resistente a meticilina (MRSP) el aislado mas frecuente en 15 perros. MRSP fue aislado en dos propietarios con infecciones de la piel causadas por MRSP. Ambos organismos tenian el mismo patron de susceptibilidad y el mismo tipo de SCCmec. No se aislo MRSP de los propietarios tras tratar los perros durante un mes. Al menos un estafilococo coagulasa negativo (CoNS) se aislo de cada propietario, encontrandose resistencia a meticilina en 16 (64%) de los aislados. El gen mecA fue identificado en todos los aislados excepto en dos de las especies de estafilococos resistentes a meticilina. La PCR multiplex identifico SCCmec de tipo V en todos los aislados MRSP. Los aislados CoNS con el gen mecA de los propietarios contenian SCCmec tipo IVa o IVc. En conclusion, la colonizacion con aislados MRSP en los propietarios parece ser poco comun y transitoria. Portadores humanos de CoNS resistentes a meticilina en la cavidad nasal fueron comunes, pero los tipos de SCCmec fueron diferentes de los aislados caninos. Los propietarios no parecen estar en riesgo de transferencia zoonotica de organismos o de los genes de resistencia antimicrobiana de perros con infecciones causadas por MRSP, pero estos hallazgos deben ser confirmados en una poblacion mayor. Zusammenfassung Um das Zoonoserisiko durch Meticillin-resistente Staphylokokken Spezies oder durch den Transfer von resistenten Genen zwischen Hunden mit Pyodermie und ihren BesitzerInnen zu bestimmen, wurden 25 Hunde-BesitzerInnen Paare untersucht. Bei der ersten Vorstellung wurden Kulturen von den Hautveranderungen der Hunde und von den Nasenhohlen der BesitzerInnen genommen. Staphylokokkus Isolate wurden bestimmt und Antibiogramme mittels Disc-Diffusionsmethode nach Kirby-Bauer durchgefuhrt. Das Vorkommen des mecA Gens wurde mittels PCR bestimmt. Staphylococcal Cassette Chromosome (SCCmec) Typisierung wurde mittels multiplex PCR durchgefuhrt. Achtzehn Hunde hatten eine Meticillin-resistente Staphylokokken Spezies, wobei ein Meticillin-resistenter S. pseudointermedius (MRSP) von 15 Hunden isoliert wurde. MRSP wurde von zwei BesitzerInnen von Hunden mit MRSP Haut- Infektionen isoliert. Beide Organismen zeigten dieselbe Empfindlichkeit und denselben SCCmec Typ. Nachdem beide Hunde einen Monat lang behandelt worden waren, wurde der MRSP von den BesitzerInnen nicht mehr isoliert. Mindestens ein Koagulase-negativer Staphylokokkus (CoNS) wurde von jedem Besitzer/jeder Besitzerin isoliert, wobei eine Meticillin Resistenz bei 16 (64%) der Isolate gefunden wurde. Das mecA Gen wurde in allen auser zwei der Meticillin-resistenten Staphylokokken spp. bestimmt. Mittels Multiplex PCR wurde in allen MRSP das SCCmec Typ V identifiziert. Die CoNS Isolate von BesitzerInnen, welche das mecA Gen besasen, hatten entweder das SCCmec Typ IVa oder IVc. Zusammenfassend schien eine MRSP Kolonisierung der BesitzerInnen unublich und transient zu sein. Menschliche Trager von Meticillin-resistenten CoNS in der Nase waren haufig, aber die SCCmec Typen waren verschieden von denen der caninen MRSP Isolate. BesitzerInnen scheinen keinem grosen Zoonoserisiko durch eine Ubertragung von Organismen oder antimikrobiellen Resistenzgenen von Hunden mit MRSP Infektionen ausgesetzt zu sein, aber diese Ergebnisse sollten durch eine wesentlich grosere Gruppe bestatigt werden.

Staphylococcus intermedius has been long regarded as the common cause of pyoderma in dogs and other animals. Despite its clinical importance, our understanding of the population genetics and pathogenesis of S. intermedius is limited. This review summarizes recent studies which have explored the genetic diversity of S. intermedius isolates resulting in a re-classification of the species and the identification of Staphylococcus pseudintermedius as the common canine pyoderma pathogen. Also discussed will be the recent identification and spread of meticillin-resistant strains of S. pseudintermedius in the context of their molecular evolution. While our understanding of S. pseudintermedius pathogenesis is very limited, it is hoped that current genome sequencing studies will result in fresh impetus for studies of disease pathogenesis and for the design of novel therapeutic approaches for the treatment of canine pyoderma.

Background New strains of methicillin-resistant Staphylococcus aureus (MRSA) which frequently carry the Panton–Valentine leukocidin (PVL) genes have been recognized to cause invasive infections in otherwise healthy children and adults. However, the epidemiology of PVL-positive MRSA infections has not been described in children or adults with cancer.

Staphylococcus aureus is a significant cause of pulmonary colonization in cystic fibrosis (CF) patients. The optimal strategy of therapy in chronically infected patients with this pathogen is not yet established. We report a successful long-term aerosolized ampicillin treatment of a 14-year-old girl with chronic symptomatic S. aureus lung infection.

Summary Reasons for performing study: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging veterinary and zoonotic pathogen, associated with increasing reports of disease in horses. Objectives: To provide an overview of the characteristics of clinical MRSA infections in horses. Methods: A retrospective case study was performed on 115 horses admitted to 6 participating veterinary teaching hospitals in Canada and the United States between 2000 and 2006, and diagnosed with clinical MRSA infection. Descriptive statistics, univariate and multivariable analyses for community- (CA) vs. hospital-associated (HA) MRSA infections, and survival vs. nonsurvival at discharge were performed. Results: The age range of MRSA-infected horses was zero (born in hospital) to 31 years. HA (58/114, 50.9%) and CA infections (56/114, 49.1%) were equally common. Infection of surgical incisions was most frequently reported (44/115, 38.0%). Overall 93/111 (83.8%) cases survived to discharge. Previous hospitalisation and treatment with gentamicin were associated significantly with CA-MRSA, whereas infected incision sites were associated significantly with HA-MRSA. Factors significantly associated with nonsurvival included i.v. catheterisation, CA-MRSA infection and dissemination of infection to other body sites. Conclusions: Equine MRSA infections have a broad range of clinical presentations, appear to be primarily opportunistic and the overall prognosis for survival to discharge is good. Potential relevance: These results should help direct future research with regard to investigation of risk factors for equine MRSA infection in community and hospital populations.

To examine the efficacy of preoperative Staphylococcus aureus screening on postoperative methicillin-resistant S aureus (MRSA) infection rates in otolaryngology.Chart review.Postoperative MRSA infection rates in unscreened patients during a 1-year period were compared with infection rates in patients after preoperative S aureus screening was initiated. Colonized patients were treated with mupirocin and chlorhexidine preoperatively.Records of 420 patients were reviewed. In the 241 patients without screening, nine patients had S aureus infections, and there were two (0.8%) postoperative MRSA surgical-site infections. Of 179 patients after screening was initiated, 24 patients (13.4%) were colonized with S aureus and underwent preoperative treatment. There were no MRSA infections in the postoperative period.Early results show the potential benefit of preoperative S aureus screening in MRSA infection rate reduction. Although larger studies are needed, screening and treatment of MRSA colonized patients preoperatively may reduce infectious complications in otolaryngology.

Background: The aim of the present paper was to determine the rate of culture-proven nosocomial infections and evaluate the episodes of nosocomial Gram-positive (GP) bacterial infections in pediatric patients. Methods: The data of children with positive culture, who were diagnosed as having nosocomial infection on the Centers for Disease Control and Prevention criteria, were examined and only the patients with nosocomial GP bacterial infections were included in the study. Results: Between January 1997 and January 2004 a total of 836 episodes of nosocomial GP bacterial infections were observed. The most frequently seen nosocomial GP bacterial infections were primary bloodstream infections (BSI; 43%), ventriculoperitoneal shunt infections (18%), and nosocomial pneumonias (11%). Coagulase-negative staphylococci (CONS; 46%) were the most common nosocomial GP bacteria isolated, followed by Staphylococcus aureus (33%). Methicillin resistance rates for CONS and S. aureus were 85% and 25.2%; respectively. The mortality rate was 4% of all children with nosocomial GP bacterial infections in the present study. Conclusion: In the present patients primary BSI were the most common nosocomial GP bacterial infections and CONS were the most frequent GP pathogen isolated. Antimicrobial resistance in GP isolates is an increasing problem.

Infections caused by the genus Staphylococcus are of great importance for human health. Staphylococcus species are divided into coagulase-positive staphylococci, represented by S. aureus, a pathogen that can cause infections of the skin and other organs in immunocompetent patients, and coagulase-negative staphylococci (CNS) which comprise different species normally involved in infectious processes in immunocompromised patients or patients using catheters. Oxacillin has been one of the main drugs used for the treatment of staphylococcal infections; however, a large number of S. aureus and CNS isolates of nosocomial origin are resistant to this drug. Methicillin resistance is encoded by the mecA gene which is inserted in the SCC mec cassette. This cassette is a mobile genetic element consisting of five different types and several subtypes. Oxacillin-resistant strains are detected by phenotypic and genotypic methods. Epidemiologically, methicillin-resistant S. aureus strains can be divided into five large pandemic clones, called Brazilian, Hungarian, Iberian, New York/Japan and Pediatric. The objective of the present review was to discuss aspects of resistance, epidemiology, genetics and detection of oxacillin resistance in Staphylococcus spp., since these microorganisms are increasingly more frequent in Brazil.

Staphylococcus aureus penicillin-binding protein PBP2 is an enzyme involved in the last stages of peptidoglycan assembly and is an important player in the mechanism of methicillin resistance of this pathogen. PBP2 localized to the division site but its recruitment to the forming division septum was prevented after acylation by oxacillin. The presence of the antibiotic did not affect FtsZ ring maintenance nor the localization of externalized peptidoglycan precursors. Delocalization of PBP2 was also observed when its pentapeptide substrate was eliminated by addition of d-cycloserine or blocked by addition of vancomycin. Taken together these observations suggest that PBP2 is recruited to the division site by binding to its substrate, which is localized at that place. In methicillin-resistant S. aureus, addition of oxacillin does not result in delocalization of PBP2 indicating that acylated PBP2 can be maintained in place by functional PBP2A, the central element of this resistance mechanism.

Summary The aim of this work was to establish the prevalence of methicillin-resistant Staphylococci (MRS) in the animals and staff of a teaching and research farm. Samples of dairy cattle (36), beef cattle (26), sheep (19), horses (21), pigs (23), goats (23) and humans (13) were collected and screened for the presence of MRS. The detection of mecA gene was performed by PCR to determine the resistance of the samples to methicillin. Antimicrobial-resistance testing to penicillin, meropenem, ceftriaxone, cephalothin, oxacillin, levofloxacin, enrofloxacin, chloramphenicol, ciprofloxacin, gentamicin, clindamycin, erytromycin, linezolid, sulfamethoxazole/trimethoprim, tetracycline, doxycycline and vancomycin was performed on the mecA+ isolates. From the 161 samples, four methicillin-resistant coagulase-negative Staphylococci (MRCoNS) were isolated from human beings (31%), whereas none was isolated from animals (0%). No methicillin-resistant Staphylococcus aureus (MRSA) were isolated. All of the MRCoNS isolates from this work presented different antimicrobial resistance patterns. MRCoNS may be present in humans associated with animals while not present in the animals. Selective pressure outside of the farm and a lack of MRCoNS transmission between humans and animals may be responsible for this lack of correlation.

Background: Antibiotic prophylaxis for percutaneous endoscopic gastrostomy insertion remains controversial. The bacteriology of peristomal infection following percutaneous endoscopic gastrostomy insertion has been poorly studied, leading to uncertainty regarding the optimum choice of antibiotic for prophylaxis. Aim: To investigate the bacteriology of peristomal infection following percutaneous endoscopic gastrostomy insertion and to determine the contribution of methicillin-resistant Staphylococcus aureus. Methods: Nasal and pharyngeal swabs were taken from a consecutive series of patients prior to percutaneous endoscopic gastrostomy insertion over a 6-month period. Bacterial colonization and infection at the peristomal site were prospectively evaluated at days 2/3 and 7 post-insertion. Results: Thirty-one patients underwent percutaneous endoscopic gastrostomy insertion (mean age, 68 years; cerebrovascular disease, 52%). Naso-pharyngeal colonization by methicillin-resistant Staphylococcus aureus (35%) invariably led to peristomal colonization following percutaneous endoscopic gastrostomy insertion. Peristomal infection occurred in eight (26%) cases (seven (88%) methicillin-resistant Staphylococcus aureus- positive). Peristomal infection was significantly more likely to occur in patients with naso-pharyngeal methicillin-resistant Staphylococcus aureus colonization (odds ratio, 10.8; 95% confidence interval, 1.6–70.9). Conclusions: Naso-pharyngeal methicillin-resistant Staphylococcus aureus colonization invariably predicts peristomal methicillin-resistant Staphylococcus aureus colonization following percutaneous endoscopic gastrostomy insertion, and is associated with an increased peristomal infection rate. Currently recommended antibiotic prophylaxis regimens may be inappropriate in institutions with significant methicillin-resistant Staphylococcus aureus colonization rates.

BACKGROUND: Platelet transfusion-associated sepsis is usually due to donor skin flora introduced into the unit during phlebotomy. An unusual case of a platelet component contaminated with methicillin-resistant Staphylococcus aureus (MRSA) is reported. CASE REPORT: A 54-year-old man, terminally ill with progressive non-Hodgkin's lymphoma, developed fever and hypotension during a platelet transfusion. He was receiving multiple antibiotics, including vancomycin. Blood cultures taken soon after transfusion were negative. An aliquot taken from the platelet pool grew MRSA at a count of 1.6 × 108 CFUs per mL. One of the individual bags constituting the pool showed MRSA at a count of 5.1 × 108 CFUs per mL. The patient died soon after the platelet transfusion. This case was reported to the FDA and submitted to the BaCon Study. The identity of the isolate and its methicillin resistance were confirmed by the CDC as part of the BaCon Study protocol. The source of contamination of the implicated unit could not be established with certainty. CONCLUSION: The emergence of antimicrobial-resistant organisms poses additional challenges for the diagnosis and treatment of transfusion-associated sepsis. Measures to prevent or intercept the transfusion of contaminated platelets should be developed.

Aims To implement and monitor the effectiveness of a strategy to curb unnecessary use of vancomycin and teicoplanin for inpatients in a teaching hospital/tertiary referral centre where 33% of S. aureus isolates (72% from ICU patients) were methicillin resistant. Methods A sample of 182 vancomycin/teicoplanin inpatient prescriptions surveyed, revealed that only 31 (17%) conformed with Centre for Disease Control (CDC) guidelines. Following education (ward-rounds, bulletins) on appropriate CDC based guidelines for prescribing glycopeptides directed at relevant clinicians, ‘Immediate Concurrent Feedback’ (ICF) was gradually deployed throughout the hospital. This entailed review of respective inpatient records on the next working day. If the indication was deemed not to conform with our guidelines, the prescriber was issued a memo (copied to the supervising doctor). Each memo detailed the ‘errant’ incident, listed appropriate indications and explicitly advised desisting from such prescribing and suggested alternative therapy if necessary. Corresponding glycopeptide usage data for our hospital and others in Hong Kong were retrieved and analysed as were samples of records of our inpatients with staphylococcal septicaemia (pre and during ICF). Results Compared with baseline values, during 2 years of ICF, inpatient prescribing of vancomycin and teicoplanin deemed to conform increased to 71% (773/1086); difference 54% (P

We investigated the mechanism of outbreak of enterocolitis caused by methicillin-resistant Staphylococcus aureus (MRSA). Five epidemiological markers [coagulase type, enterotoxin type, toxic shock syndrome toxin-1 (TSST-1) production, beta-lactamase production and pulsed-field gel electrophoresis (PFGE)] of 45 strains of MRSA isolated simultaneously from the respiratory tract (nasal cavity and/or pharynx and/or sputum) and stool (plus one sample of gastric juice) in 13 patients (8 males and 5 females, mean age, 77.1 years) were compared retrospectively. Forty-four of the 45 isolates of MRSA were positive for enterotoxin C and TSST-1 production, and the remaining isolate was positive for enterotoxin A and negative for TSST-1 production. All isolates were coagulase type II, and 27 showed beta-lactamase production. The patterns of coagulase type, enterotoxin type, TSST-1 and beta-lactamase production of MRSA isolated from the respiratory tract were similar to those of MRSA isolated from the intestine in 12 of 13 patients. Molecular typing by PFGE demonstrated that the pattern of respiratory tract isolates was identical to those of stool isolates in 9 (69.2%), similar in 3 (23.1 %), and different in 1 (7.7%). The data suggested that enterocolitis might be caused by the MRSA colonized in the respiratory tract and incorporated into the digestive tracts. Therefore, we propose that early eradication of MRSA in the respiratory tract is important for protection of patients against the development of enterocolitis, particularly in susceptible patients, e.g., immunocompromised or pre-operated patients with digestive diseases, especially malignant disease.

An outbreak caused by rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) in an intensive care unit for cardiovascular surgery was investigated by phenotypic and genotypic methods. Fourteen isolates were collected during a 2-month period from clinical and environmental specimens in the unit recently re-opened after reconstruction. The isolates were tested for antibiotic susceptibility patterns and genotyped by automated ribotyping, randomly amplified polymorphic DNA-PCR (RAPD) analysis and pulsed-field gel electrophoresis (PFGE). Automated ribotyping applying EcoRI digestion proved to be of no value in separating the isolates. In contrast, PFGE grouped the isolates into four clusters different from the reference strain. These results fully correlated with the antibiograms. Twelve of the isolates were grouped into two clonally related clusters. RAPD analyses grouped the isolates into five clusters. Except for two isolates of one patient, which had different RAPD patterns, PFGE and RAPD analyses presented very similar results. The results verified the usefulness of PFGE in studies of MRSA epidemics. A combination of these two methods reduces the time to identification of an outbreak and increases the accuracy in detection of intraspecies differences.

Background Antimicrobial resistance within bacteria continues to present therapeutic challenges. One presumed risk factor for increased rates of resistance is prior exposure to antimicrobial drugs. Objectives To examine the impact of time since most recent exposure, the number of prior antimicrobial exposures and duration of use on antimicrobial resistance rates in Staphylococcus pseudintermedius isolates. Methods Inclusion of a case in the study required laboratory isolation of S. pseudintermedius from a clinical specimen. Antibiograms and information regarding prior antimicrobial exposures were extracted from the medical records of dogs diagnosed with pyoderma or otitis externa. Results Meticillin resistance (MR) was identified in 48.1% of isolates. Recent use of beta-lactam antimicrobials was associated with increased odds of resistance to meticillin (P