RESUMO
Methicillin-resistant Staphylococcus (MRS) has been associated with neonatal infections, with colonization of the anovaginal tract being the main source of vertical transmission. The COVID-19 pandemic has altered the frequency of antibiotic usage, potentially contributing to changes in the dynamics of bacterial agents colonizing humans. Here we determined MRS colonization rates among pregnant individuals attending a single maternity in Rio de Janeiro, Brazil before (January 2019-March 2020) and during (May 2020-March 2021) the COVID-19 pandemic. Anovaginal samples (n = 806 [521 samples before and 285 during the pandemic]) were streaked onto chromogenic media. Colonies were identified by MALDI-TOF MS. Detection of mecA gene and SCCmec typing were assessed by PCR and antimicrobial susceptibility testing was done according to CLSI guidelines. After the onset of the pandemic, MRS colonization rates increased significantly (p < 0.05) from 8.6% (45) to 54.7% (156). Overall, 215 (26.6%) MRS isolates were detected, of which S. haemolyticus was the most prevalent species (MRSH, 84.2%; 181 isolates). SCCmec type V was the most frequent among MRS (63.3%; 136), and 31.6% (68) of MRS strains had a non-typeable SCCmec, due to new combinations of ccr and mecA complexes. Among MRS strains, 41.9% (90) were resistant to at least 3 different classes of antimicrobial agents, and 60% (54) of them were S. haemolyticus harboring SCCmec V. MRS colonization rates and the emergence of multidrug-resistant variants detected in this study indicate the need for continuing surveillance of this important pathogen within maternal and child populations.
Assuntos
COVID-19 , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Feminino , Gravidez , COVID-19/epidemiologia , COVID-19/virologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Adulto , Brasil/epidemiologia , Complicações Infecciosas na Gravidez/microbiologia , Complicações Infecciosas na Gravidez/epidemiologia , Antibacterianos/farmacologia , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Testes de Sensibilidade Microbiana , Pandemias , Vagina/microbiologiaRESUMO
Background: Methicillin resistance and biofilm-producing Staphylococci are emerging as multidrug-resistant strains narrowing the efficacy of antimicrobial therapy. Although vancomycin is used as the drug of choice to treat such isolates, different studies worldwide have documented the emergence of strains that are intermediately susceptible or resistant to this antibiotic. Objective: The study aimed to determine the minimum inhibitory concentration of vancomycin to methicillin-resistant and biofilm-producing staphylococci isolated from different clinical specimens. Methods: 375 staphylococci isolated from different clinical specimens over one year were included in the study. Biofilm formation was determined by the Tissue culture plate method (TCP), and ica genes were identified by Polymerase Chain Reaction (PCR). Antibiotic susceptibility and methicillin resistance were done following Clinical and Laboratory Standards Institute (CLSI) guidelines. The minimum inhibitory concentration (MIC) of vancomycin in all isolates was determined by the agar dilution method. Results:Among 375 Staphylococci studied, 43% and 57% represented S. aureus and Coagulase-Negative Staphylococci (CNS), respectively. The rate of Methicillin-Resistant S. aureus (MRSA) and Methicillin-Resistant Coagulase Negative Staphylococci (MRCNS) were 81.4% and 66.8% respectively and determined by the disc diffusion method. The most potential antibiotics were tetracycline and chloramphenicol showing sensitivity to more than 90% isolates. The Minimum Inhibitory Concentration (MIC) value of oxacillin for staphylococci ranged from 0.125-32 µg/ml. Oxacillin agar diffusion method showed 51.6% and 79.9% isolates as MRSA and MRCNS, respectively, revealing a very high percentage of S. aureus and CNS isolates as methicillin-resistant. All isolates had susceptible vancomycin MICs that ranged from 0.125-2 µg/ml. Two S. aureus isolated from Central Venous Catheter (CVC) and catheter specimens were detected with intermediate susceptibility to vancomycin. Similarly, three CNS isolated from blood, CVC, and wound/pus (w/p) were intermediately susceptible to vancomycin. Strong biofilm formation was observed in 22.1% of clinical isolates, and the ica gene was detected among 22.9% of isolates. Only one S. aureus detected as a biofilm producer by the TCP method was found to have intermediate susceptibility to vancomycin. Conclusions: The increment in vancomycin MIC among methicillin-resistant and biofilm-producing staphylococci is alarming. Strict control measures to prevent methicillin-resistant isolates spread and routine surveillance for vancomycin-resistant isolates must be incorporated in hospitals to prevent antimicrobial treatment failure
Antecedentes: Los estafilococos resistentes a la meticilina y productores de biopelículas están surgiendo como cepas multirresistentes que reducen la eficacia del tratamiento antimicrobiano. Aunque la vancomicina se utiliza como fármaco de elección para tratar dichos aislados, diferentes estudios realizados en todo el mundo han documentado la aparición de cepas intermedias susceptibles o resistentes a este antibiótico. Objetivo: El estudio tenía como objetivo determinar la concentración mínima inhibitoria de la vancomicina para los estafilococos resistentes a la meticilina y productores de biofilm aislados de diferentes muestras clínicas. Métodos: Se incluyeron en el estudio 375 estafilococos aislados de diferentes muestras clínicas durante un año. La formación de biopelículas se determinó mediante el método de la placa de cultivo de tejidos (TCP), y los genes ica se identificaron mediante la reacción en cadena de la polimerasa (PCR). La susceptibilidad a los antibióticos y la resistencia a la meticilina se realizaron siguiendo las directrices del Clinical and Laboratory Standards Institute (CLSI). La concentración inhibitoria mínima (MIC) de vancomicina en todos los aislados se determinó por el método de dilución en agar. Resultados:Entre los 375 estafilococos estudiados, el 43% y el 57% representaban S. aureus y estafilococos coagulasa-negativos (ECN), respectivamente. La tasa de S. aureus resistente a la meticilina (SARM) y de estafilococos coagulasa negativos resistentes a la meticilina (ECNM) fue del 81,4% y el 66,8%, respectivamente, y se determinó por el método de difusión de discos. Los antibióticos más potenciales fueron la tetraciclina y el cloranfenicol, que mostraron una sensibilidad superior al 90% de los aislados. El valor de la concentración inhibitoria mínima (CIM) de la oxacilina para los estafilococos osciló entre 0,125-32 µg/ml. El método de difusión en agar de la oxacilina mostró que el 51,6% y el 79,9% de los aislados eran SARM y MRCNS, respectivamente, lo que revela que un porcentaje muy elevado de los aislados de S. aureus y CNS son resistentes a la meticilina. Todos los aislados tenían MIC de vancomicina susceptibles que oscilaban entre 0,125-2 µg/ml. Se detectaron dos S. aureus aislados de muestras de catéteres venosos centrales (CVC) y catéteres con una susceptibilidad intermedia a la vancomicina. Del mismo modo, tres S. aureus aislados de sangre, CVC y herida/pus (w/p) fueron intermedianamente susceptibles a la vancomicina. Se observó una fuerte formación de biopelículas en el 22,1% de los aislados clínicos, y se detectó el gen ica en el 22,9% de los aislados. Sólo un S. aureus detectado como productor de biopelículas por el método TCP resultó tener una susceptibilidad intermedia a la vancomicina. Conclusiones: El incremento de la MIC de vancomicina entre los estafilococos resistentes a la meticilina y productores de biofilm es alarmante. Para evitar el fracaso del tratamiento antimicrobiano, deben incorporarse en los hospitales medidas de control estrictas para prevenir la propagación de los aislados resistentes a la meticilina y una vigilancia rutinaria de los aislados resistentes a la vancomicina
Assuntos
Humanos , Vancomicina/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , Resistência a VancomicinaRESUMO
In light of the scarcity of information about the occurrence and epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MRCNS) in small ruminants in general, and particularly dairy goats, we launched this limited-scope study. The findings reported here show the detection of MRSA and MRCNS in goat milk and teat skin samples from dairy goat herds in the state of Ohio. A total of 120 milk samples and 120 teat-swab samples were collected from 5 farms. After conventional isolation and phenotypic characterization of the staphylococci colonies, bacterial isolates were tested by PCR assay targeting the genes nuc to identify Staphylococcus aureus and mecA to detect MRSA and MRCNS. The clonal complexes of MRSA isolates was also determined by multiloccus sequence typing. Fifteen (6.2%) positive S. aureus samples were found in this study: 9 from milk and 6 from teat skin samples. Four (2%) MRSA isolates were detected and, using multiloccus sequence typing genotyping, these were designated to clonal complexes CC133 (n = 2; milk samples) and CC5 (n = 2; teat skin). Three (1.25%) coagulase-negative staphylococci isolates from the teat skin also harbored the mecA gene. Although, the MRSA isolated from milk samples is not a typical human-associated lineage, the CC5 clone isolated from teat skin is a common and widespread clonal complex associated with humans, suggesting that this extramammary niche could be a relevant reservoir of methicillin-resistant staphylococci. Furthermore, the fact that 75% of MRSA were recovered from 1 farm showing poor hygiene practices strengthens the hypothesis that good hygiene practices could be useful to prevent persistence and spread of MRSA at a farm level.
Assuntos
Doenças das Cabras/epidemiologia , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Coagulase/metabolismo , Doenças das Cabras/tratamento farmacológico , Cabras , Meticilina/farmacologia , Testes de Sensibilidade Microbiana , Ohio , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologiaRESUMO
Bacteria of the genus Staphylococcus are one of the major pathogens causing bovine mastitis. In recent decades, resistance of this genus to oxacillin (methicillin) has been a matter of concern due to the possibility of reducing the effectiveness of mastitis treatments and the transfer of resistance determinants to other bacteria. Oxacillin resistance was studied in 170 staphylococci from bovine milk samples, including 79 Staphylococcus aureus and 91 coagulase-negative staphylococci (CNS). The susceptibility profile of 10 antimicrobial agents used in veterinary practice was determined by the Etest method. In addition to the Etest, the phenotypic characterization of oxacillin resistance was tested using the cefoxitin disk diffusion test. All isolates were screened by PCR to detect the mecA gene in 2 different regions of the gene. The isolates with an oxacillin minimum inhibitory concentration ≥0.5 µg/mL or resistant to cefoxitin were identified by sequencing a 536-bp fragment of the 16S rRNA gene. This group of isolates was also evaluated for the presence of blaZ and mecC genes. Molecular analysis of the mecA gene was carried out by typing of the staphylococcal cassette chromosome mec (SCCmec). The relatedness of the mecA-positive isolates was evaluated by macrorestriction of chromosomal DNA followed by pulsed-field gel electrophoresis. With the exception of penicillin and oxacillin, 86% of the isolates showed susceptibility to cephalothin, gentamicin, erythromycin, sulfonamide, trimethoprim-sulfamethoxazole, and tetracycline. All S. aureus isolates were susceptible to oxacillin, whereas 47% (n=43) of the CNS isolates were resistant. The CNS isolates showed a higher resistance to cephalothin, erythromycin, tetracycline, and gentamicin in comparison with S. aureus. The mecA gene was only detected in 10 CNS isolates, identified as Staphylococcus epidermidis, and classified into 3 pulsotypes (A, B, and C) and 4 subtypes (A1, B1, B2, and B3). Among the isolates with an oxacillin resistance phenotype, 12 were positive for the blaZ gene, and 9 of them were mecA-positive. Two of the oxacillin-resistant isolates amplified the mecA homolog gene of Staphylococcus sciuri and none amplified mecC. Three SCCmec types, I, IV, and V, were found. Our results suggest that Staphylococcus epidermidis can be a reservoir for mecA for other Staphylococcus species. Studies investigating the molecular and phenotypic profile of antimicrobial resistance in staphylococcal species should be performed for controlling the spread of resistance and the selection of appropriate therapeutic measures.