Long-Term Co-Circulation of Host-Specialist and Host-Generalist Lineages of Group B Streptococcus in Brazilian Dairy Cattle with Heterogeneous Antimicrobial Resistance Profiles.

Group B Streptococcus (GBS) is a major cause of contagious bovine mastitis (CBM) in Brazil. The GBS population is composed of host-generalist and host-specialist lineages, which may differ in antimicrobial resistance (AMR) and zoonotic potential, and the surveillance of bovine GBS is crucial to developing effective CBM control and prevention measures. Here, we investigated bovine GBS isolates (n = 156) collected in Brazil between 1987 and 2021 using phenotypic testing and whole-genome sequencing to uncover the molecular epidemiology of bovine GBS. Clonal complex (CC) 61/67 was the predominant clade in the 20th century; however, it was replaced by CC91, with which it shares a most common recent ancestor, in the 21st century, despite the higher prevalence of AMR in CC61/67 than in CC91, and high selection pressure for AMR from indiscriminate antimicrobial use in the Brazilian dairy industry. CC103 also emerged as a dominant CC in the 21st century, and a considerable proportion of herds had two or more GBS strains, suggesting poor biosecurity and within-herd evolution due to the chronic nature of CBM problems. The majority of bovine GBS belonged to serotype Ia or III, which was strongly correlated with CCs. Ninety-three isolates were resistant to tetracycline (≥8 µg/mL; tetO = 57, tetM = 34 or both = 2) and forty-four were resistant to erythromycin (2.0 to >4 µg/mL; ermA = 1, ermB = 38, mechanism unidentified n = 5). Only three isolates were non-susceptible to penicillin (≥8.0 µg/mL), providing opportunities for improved antimicrobial stewardship through the use of narrow-spectrum antimicrobials for the treatment of dairy cattle. The common bovine GBS clades detected in this study have rarely been reported in humans, suggesting limited risk of interspecies transmission of GBS in Brazil. This study provides new data to support improvements to CBM and AMR control, bovine GBS vaccine design, and the management of public health risks posed by bovine GBS in Brazil.

Staphylococcus saprophyticus Recovered from Humans, Food, and Recreational Waters in Rio de Janeiro, Brazil.

Staphylococcus saprophyticus is an important agent of urinary tract infection (UTI) in young women, but information about this pathogen in human microbiota and in common environment is lacking. The aim of this study was to characterize S. saprophyticus isolates from genitoanal microbiota of 621 pregnant women, 10 minas cheese packs, and five beaches in Rio de Janeiro city and compare PFGE profiles of these isolates with five UTI PFGE clusters described in this city. We investigated 65 S. saprophyticus isolates from microbiota, 13 from minas cheese, and 30 from beaches and 32 UTI isolates. Antimicrobial resistance was determined by disk diffusion, MIC by agar dilution, and PCR. Erythromycin-resistance genes erm(C), msr(A), msr(B), mph(C), and lin(A) were found in 93% of isolates. Trimethoprim-sulfamethoxazole resistance correlated with dfrG or dfrA genes. Three cefoxitin-resistant isolates carried the mecA gene. All isolates obtained from cheese were susceptible to all antimicrobial agents. Six of 10 pregnant women with >1 isolate had monoclonal colonization. Isolates from pregnant women shared 100% similarity with UTI PFGE cluster types A and E obtained almost 10 years previously, suggesting temporal persistence of S. saprophyticus. Antimicrobial resistance of beach isolates reflected the profiles of human isolates. Taken together, results indicate a shared source for human and environmental isolates.

Mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swab specimens in Brazil.

The isolation of mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swabs is reported. Among the 59 isolates, 9 (15%) isolates were mannitol-negative; all of these isolates were categorized as staphylococcal cassette chromosome mec (SCCmec) type IVa. This report emphasizes that mannitol fermentation on mannitol salt agar should not be used as the sole criterion when screening nasal swab specimens for S. aureus.

Mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swab specimens in Brazil

The isolation of mannitol-negative methicillin-resistant Staphylococcus aureus from nasal swabs is reported. Among the 59 isolates, 9 (15%) isolates were mannitol-negative; all of these isolates were categorized as staphylococcal cassette chromosome mec (SCCmec) type IVa. This report emphasizes that mannitol fermentation on mannitol salt agar should not be used as the sole criterion when screening nasal swab specimens for S. aureus.

Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections.

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

Time-based distribution of Staphylococcus saprophyticus pulsed field gel-electrophoresis clusters in community-acquired urinary tract infections

The epidemiology of urinary tract infections (UTI) by Staphylococcus saprophyticus has not been fully characterised and strain typing methods have not been validated for this agent. To evaluate whether epidemiological relationships exist between clusters of pulsed field gel-electrophoresis (PFGE) genotypes of S. saprophyticus from community-acquired UTI, a cross-sectional surveillance study was conducted in the city of Rio de Janeiro, Brazil. In total, 32 (16%) female patients attending two walk-in clinics were culture-positive for S. saprophyticus. Five PFGE clusters were defined and evaluated against epidemiological data. The PFGE clusters were grouped in time, suggesting the existence of community point sources of S. saprophyticus. From these point sources, S. saprophyticus strains may spread among individuals.

A cluster of Listeria monocytogenes infections in hospitalized adults.

BACKGROUND: Listeriosis occurs mainly in persons at extremes of age and with immunocompromising conditions. It is believed that most cases of listeriosis are acquired in the community. A cluster of listeriosis in hospitalized patients prompted the present investigation. METHODS: We conducted a case series study of listeriosis from August 21, 2006, to June 1, 2007, in a hospital in the city of Rio de Janeiro, Brazil. RESULTS: Six patients with Listeria monocytogenes infection were identified: 5 during hospitalization and 1 at a day clinic. By the time the infection was diagnosed, 5 patients had been in the hospital for a mean of 9 days. All patients were elderly (median age, 80 years) and had immunocompromising conditions. Five (83%) patients died. Four patients developed bloodstream infections, 3 caused by serotype 1/2b. Two patients had peritonitis: one caused by serotype 3b and another by serotype 1/2b. Four L monocytogenes isolates belonged to a single pulse-field gel electrophoresis genotype, suggesting a common source. An epidemiologic investigation pointed to the hospital kitchen as the possible contamination. CONCLUSION: Data suggest a health care-associated outbreak of listeriosis and highlight the importance of developing guidelines for prevention and treatment of health care-associated foodborne diseases, especially in hospitals with immunocompromised adult patients.

Staphylococcus Aureus resistente a Vancomicina: uma realidade clínica / Staphylococcus Aureus Vancomicin resistance: a clinic reality

O staphylococcus aureus é, hoje, um dos agentes infecciosos que mais preocupam os clínicos, principalmente, face à rapidez com a qual desenvolve resistencia à antibioticoterapia. Isto contrasta com o inicio da era antibiótica, no começo da década de 40, quando as estafilococcias por S.Aureus eram plenamentecuradas por penicilina G. Ja no final da década, entretanto, surgiram os primeiros casos de resistência àquele betalactamico, através da produçäo de penicilinase (uma beta-lactamase).Nos anos 50, esta resistência já era de ordem de 50 por cento. Em 1960, entretanto, a sistese da meticilina (uma penicilina resistente a beta-lactamase), juntamente com a descoberta das cefalosporinas orais, deu a impressäo de que as infecçöes por S.Aureus estavam superadas. Mero engano: em 1970, apareceram as cepas de S.Aureus resistentes à meticilina: MRSA (methicillin-resistan-Staphylococcus aureus). Foi ai que a vancomicina (disponivel desde 1958) apareceu como droga salvadora, graças à sua alta eficiência contra as cepas MRSA. Desafortunadamente, porém, já há registro na literatura médica de cepa MRSA com resistência à vancomicina (CMI 8µg/mL). Deste modo, a cura das infecçöes por MRSA passa a depender, também, da descoberta de novos e mais eficazes antibióticos. Paralelamente a esta busca, uma antibioticoterapia mais racional deverá ser praticada, a fim de evitar a induçäo ou a seleçäo de cepas de bactérias resistentes e tolerantes, sob pena de ingressarmos na era pós-antibiótica, provavelmente, mais crítica do que a pré-antibiótica, quando aquelas cepas ainda nao haviam sido selecionadas