Gangrenous mastitis in sheep caused by multidrug-resistant Staphylococcus haemolyticus / Mastite gangrenosa em ovinos causada por Staphylococcus haemolyticus multirresistente

Mastitis is a multifactorial disease and considered one of the most critical problems in the dairy industry worldwide. The condition is characterized by reduced milk and several abnormalities in the mammary gland. This study aimed to report an outbreak of gangrenous mastitis caused by multidrug-resistant Staphylococcus haemolyticus in a Santa Inês sheep herd. Eighteen sheep were affected, and five of them with severe clinical pictures were examined. The clinical and pathological picture were variable and characterized by apathy, anorexia, emaciation, opaque and brittle hair, apparent and congested episcleral vessels, and hyperthermia. These ewes had enlarged, firm, and painful mammary glands. Macroscopically, these lesions consisted of severe gangrenous mastitis, and microscopically, the primary lesions consisted of necrosis, thrombosis, and fibrosis of the mammary parenchyma. Milk samples from one of the five severely affected ewes were collected and cultured under aerobic or microaerophilic incubation at 37°C for 24 hours on sheep blood agar. The obtained colonies were then submitted to MALDI-TOF for speciation. The colonies were also submitted to an antimicrobial susceptibility test, genotyping of virulence factors and resistance genes were also performed. The isolates showed antimicrobial multiresistance since they were resistant to seven out of 13 tested antibiotics. The isolates were also positive for two staphylococcal enterotoxigenic genes (sec and see) and fibronectin-binding protein B (fnbB).(AU)

A mastite é uma doença multifatorial e é considerada um dos problemas mais importantes na indústria de laticínios no mundo todo. A condição é caracterizada pela redução de leite e várias anormalidades na glândula mamária. O objetivo deste estudo foi relatar um surto de mastite gangrenosa causada por Staphylococcus haemolyticus multirresistente em um rebanho ovino Santa Inês. Dezoito ovelhas foram afetadas e cinco delas com quadro clínico severo foram examinadas. O quadro clínico-patológico era variável quanto a severidade e consistia em apatia, anorexia, magreza, pelos opacos e quebradiços e vasos episclerais aparentes e ingurgitados. As ovelhas apresentavam glândulas aumentadas, firmes e dolorosas. Macroscopicamente, as principais lesões consistiam em mastite gangrenosa e microscopicamente havia necrose do parênquima glandular, trombose e fibrose. Amostras de leite de uma das cinco ovelhas severamente afetadas foram coletadas e cultivadas sob incubação aeróbica ou microaerofílica a 37°C por 24 horas em ágar sangue de ovelha. As colônias obtidas foram então submetidas ao MALDI-TOF para especiação. Além disso, as colônias foram submetidas a um teste de suscetibilidade antimicrobiana e foi realizada a genotipagem de fatores de virulência e genes de resistência. Os isolados apresentaram multirresistência antimicrobiana por serem resistentes a sete dos 13 antibióticos testados. Os isolados também foram positivos para dois genes enterotoxigênicos estafilocócicos (sec e see) e proteína B de ligação à fibronectina (fnbB).(AU)

Characterization of mannitol-fermenting methicillin-resistant staphylococci isolated from pigs in Nigeria

This study was conducted to determine the species distribution, antimicrobial resistance pheno- and genotypes and virulence traits of mannitol-positive methicillin-resistant staphylococci (MRS) isolated from pigs in Nsukka agricultural zone, Nigeria. Twenty mannitol-positive methicillin-resistant coagulase-negative staphylococcal (MRCoNS) strains harboring the mecA gene were detected among the 64 Staphylococcus isolates from 291 pigs. A total of 4 species were identified among the MRCoNS isolates, namely, Staphylococcus sciuri (10 strains), Staphylococcus lentus (6 strains), Staphylococcus cohnii (3 strains) and Staphylococcus haemolyticus (one strain). All MRCoNS isolates were multidrug-resistant. In addition to β-lactams, the strains were resistant to fusidic acid (85%), tetracycline (75%), streptomycin (65%), ciprofloxacin (65%), and trimethoprim/sulphamethoxazole (60%). In addition to the mecA and blaZ genes, other antimicrobial resistance genes detected were tet(K), tet(M), tet(L), erm(B), erm(C), aacA-aphD, aphA3, str, dfrK, dfrG, cat_pC221, and cat_pC223. Thirteen isolates were found to be ciprofloxacin-resistant, and all harbored a Ser84Leu mutation within the QRDR of the GyrA protein, with 3 isolates showing 2 extra substitutions, Ser98Ile and Arg100Lys (one strain) and Glu88Asp and Asp96Thr (2 strains). A phylogenetic tree of the QRDR nucleotide sequences in the gyrA gene revealed a high nucleotide diversity, with several major clusters not associated with the bacterial species. Our study highlights the possibility of transfer of mecA ...

Intravenous device associated blood stream staphylococcal infection in paediatric patients.

Background & objectives: Intravenous device (IVD) associated nosocomial blood stream infections due to staphylococci are major cause of morbidity and mortality. The present study was carried out to assess the frequency of staphylococcal IVD associated infections in a paediatric ward of a tertiary case hospital. Prevalence of resistance to commonly used antimicrobials in hospital acquired staphylococcal isolates was also tested. Methods: Children admitted in paediatric wards with IVD for more than 48 h were enrolled. Blood, IVD tip at the time of removal, skin swab at the site of insertion of IVD and nasal swab were collected and cultured by standard protocol. All staphylococcal isolates from any source were analyzed for antimicrobial susceptibility by disk diffusion method. Genotyping matching of those staphylococcal isolates was done which were isolated from different sites of the same patient, but were phonotypically similar. Genotype of blood isolate was compared with genotype of isolate from nose/IVD/skin. Results: Staphylococcus aureus was the most frequent blood isolate (8.7%) followed by Candida (2.9%), coagulase negative staphylococci (CoNS 2.6%), Pseudomonas spp. (0.4%), Klebsiella spp. (0.3%) and Escherichia coli (0.1%). Isolation of microorganisms from blood was significantly higher in patients whose skin, IVD and nose were colonized by same microorganism (P<0.001). None of the staphylococcal isolate was found to be resistant to glycopeptides (vancomycin and teicoplanin). High penicillin and oxacillin resistance was present in both S. aureus (penicillin resistance; 76.8%, oxacillin resistance; 66.7%) and CoNS (penicillin resistance; 73.3%, oxacillin resistance; 60.0%). Among CoNS biotypes, S. haemolyticus was commonest blood isolate while S. epidermidis was commonest isolate from Skin/nose. Only 33.3 per cent of S. aureus blood stream infections and most of S. epidermidis and S. haemolyticus blood infections were IVD associated. Interpretation & conclusions: Staphylococci were the major causative agent of nosocomial blood stream infections. All episodes of septicaemia due to S. epidermidis and S. haemolyticus were IVD associated while only 1/3 of S. aureus septicaemia was IVD associated.

Detecção da produção de slime por estafilococos coagulase-negativa isolados de cateter venoso central / Detection of slime production by coagulase-negative staphylococci isolated from central venous catheter

A produção de slime é um importante fator de virulência dos estafilococos coagulase-negativa, permitindo-lhes aderir sobre as superfícies lisas de biomateriais, e por isso, é associada aos processos de infecção de implantes. No presente estudo a produção de slime em 27 cepas de estafilococos coagulase-negativa foi investigada por cultura em ágar vermelho Congo (77,7% de positividade), método espectrofotométrico ou damicroplaca (81,4% de positividade) e microscopia eletrônica de varredura (88,9% de positividade). Foi também avaliada a resistência de estafilococos coagula-se negativa a vários antimicrobianos usando a técnica do disco difusão. A porcentagem de resistência à penicilina G, oxacilina, eritromicina, clindamicina e gentamicinaem estafilococos produtores de slime foi respectivamente de 88,9%; 70,4%; 81,5%; 66,7% e 59,2%; todos os estafilococos coagulase-negativa foram vancomicina sensíveis. As cepas isoladas de cateter venoso central foram identificadas por método convencional e sistema API Staph. Os 27 estafilococos coagulase-negativa foram identificados como: S. saprophyticus (3,7%), S. xylosus(7,4%), S. haemolyticus (14,8%), S. epidermidis (37,0%), S. warneri (14,8%), S. lugdunensis (7,4%), S. hominis (7,4%), S. schleiferi (3,7%) e S. chromogenes (3,7%). Pode-se concluir que entre a maioria das espécies Staphylococcus coagulase-negativa houve associação entre a produção de slime, origem nosocomial das cepase reduzida sensibilidade aos antimicrobianos, sugerindo potencial patogênico no ambiente hospitalar.

Slime production is an important virulence factor of coagulase-negative Staphylococcus spp., allowing them to attach to smooth surfaces of biomaterials, and it has been associated with infections of implanted medical devices. In the present study the production of slime capsules in 27 strains of coagulase-negative Staphylococcus was investigated by culture in Congo Red agar (77.7% positivity), spectrophotometric or microplate method (81.4% positivity) and scanning electron microscopy (88.9% positivity). The resistance of coagulase-negative strains of Staphylococcus to various antimicrobial agents was also determined by agar disk diffusion. The proportion of strains resistant to penicillin G, oxacillin, erythromycin, clindamycin and gentamicin among the slime-producing staphylococci was 88.9%, 70.4%, 81.5%, 66.7% and 59.2%, respectively; all of the coagulase-negative staphylococci were susceptible to vancomycin. The strains isolated from central venous catheters were identified by a conventional method and the API Staph system. The 27 coagulase-negative taphylococcus strains were identified as: S. saprophyticus (3.7%), S. xylosus (7.4%), S. haemolyticus (14.8%), S. epidermidis (37.0%), S. warneri (14.8%), S. lugdunensis (7.4%), S. hominis (7.4%), S. schleiferi (3.7%) and S. chromogenes (3.7%). It can be concluded that in the most of the coagulase-negative Staphylococcus species there was an association between slime production, the nosocomial origin of the strains and reduced sensitivity to the antibiotics, suggesting a pathogenic potential in the hospital environment.