Stimulation of human immunodeficiency virus (HIV) type 1 expression by Gardnerella vaginalis is one possible cause for an increase in the amount of virus in the genital tract. The ability of G. vaginalis to induce HIV expression in chronically infected U1 cells was investigated, along with its possible relationship to biotype, genotype, and resistance to metronidazole and bacteriocin. Significant HIV stimulatory activity was found in 5 (50%) lysates of G. vaginalis. The ability to induce HIV expression in U1 cells was statistically associated with G. vaginalis biotype (P=.048) but not with genotype or resistance to metronidazole and bacteriocin. Further studies to explore the in vivo relevance of HIV activation by G. vaginalis in the female genital tract are warranted, since prevention strategies of bacterial vaginosis and colonization by certain biotypes of G. vaginalis may be valuable in reducing the risk of sexual transmission of HIV
Objective. To evaluate the safety of the antimicrobial peptide, lactocin 160. Methods. Lactocin 160, a product of vaginal probiotic Lactobacillus rhamnosus 160 was evaluated for toxicity and irritation. An in vitro human organotypic vaginal-ectocervical tissue model (EpiVaginal) was employed for the safety testing by determining the exposure time to reduce tissue viability to 50% (ET-50). Hemolytic activity of lactocin160 was tested using 8% of human erythrocyte suspension. Susceptibility of lactobacilli to lactocin160 was also studied. Rabbit vaginal irritation (RVI) model was used for an in vivo safety evaluation. Results. The ET-50 value was 17.5 hours for lactocin 160 (4.9 hours for nonoxynol 9, N9). Hemolytic activity of lactocin 160 was 8.2% (N9 caused total hemolysis). Lactobacilli resisted to high concentrations of peptide preparation. The RVI model revealed slight vaginal irritation. An average irritation index grade was evaluated as “none.” Conclusions. Lactocin 160 showed minimal irritation and has a good potential for intravaginal application.
Abstract Background Hospital-onset (HO) methicillin-resistant Staphylococcus aureus (MRSA) infections have declined over the past decade due to infection control strategies; community-onset (CO) and healthcare-associated community-onset (HACO) MRSA, particularly USA300, has declined less. We examined the role of community strains to explain the difference. Methods We performed whole-genome sequencing (WGS) on MRSA clinical isolates from Cook County Health patients during 2011–2014. We defined infections as CO, HO, or HACO epidemiologically. We integrated genomic, community exposure, and statewide hospital discharge data to infer MRSA origin. Results Among 1020 individuals with available WGS, most were USA300 wound infections (580 CO, 143 HO, 297 HACO). USA300 HO, CO, and HACO infections were intermixed on the USA300 phylogeny, consistent with common strains circulating across community and healthcare settings. Community exposures (eg, substance abuse, incarceration, homelessness) were associated with HACO and HO infections, and genetically linked individuals from both groups had little overlap in healthcare facilities, supporting community origins. Most repeat infections—over months to years—occurred in individuals persistently carrying their own strains. These individuals were more likely to have genetic linkages, suggesting a role of persistent colonization in transmission. Conclusions Efforts to reduce presumed nosocomial USA300 spread may require understanding and controlling community sources and transmission networks, particularly for repeat infections.
Background: Previous work suggests an intermingling of community and hospital transmission networks driving the MRSA epidemic, but how those with CO-HA infections fit into the network remains unclear. We integrated epidemiologic data and whole-genome sequencing (WGS) from existing MRSA clinical isolates to determine whether there were distinguishable features of CO-HA MRSA infections that could guide interventions. Methods: We examined 955 existing clinical MRSA isolates from 2011 to 2013 from patients at Cook County Health, the major public healthcare network in Chicago, Illinois. We performed electronic and manual chart review to ascertain community (eg, illicit drug use, incarceration history) and healthcare exposures and comorbidities. WGS was performed on all sequences, and sequences were typed with multilocus sequence typing (MLST). We assessed the distribution of epidemiological factors and sequence type (ST) across onset type. Results: Infections were more frequent in males (70%); 61% of individuals with infection were African American and 21% were Hispanic. Overall, wound infections were the most common (81%) followed by blood (7%) and respiratory (6%). 82% of infections were ST8 (most USA300), 8% were ST5 (USA100) and 10% were other STs (Fig. 1a). Using standard epidemiologic definitions, we identified 523 CO, 295 CO-HA, and 137 HO infections. USA300 infections were common across CO, CO-HA, and HO categories, whereas USA100 was more frequently observed among CO-HA and HO. Current illicit drug use and history of incarceration—factors typically associated with CO-MRSA—were observed among both CO-HA and HO infections. 38% of CO-HA and 36% of HO had a history of MRSA infection or nasal colonization in the prior 6 months. As expected, 73% of CO-HA had a history of recent hospitalization, but this was also true for 44% of HO cases; points for intervention for both groups, especially CO-HA patients, include outpatient, inpatient, and ER care. Diabetes was common across categories, and HIV was more commonly observed among CO-HA cases (Fig. 1b). Conclusions: We characterized the genomic and epidemiologic features of CO-HA MRSA infections relative to CO and HO. By MLST and epidemiological analysis, CO-HA infections share similarities to both CO and HO. Although USA300 infections were the most common strain type, our findings highlight the need for WGS to discern relationships between individuals to understand the intermixing of healthcare and community networks for CO-HA infections. Higher resolution genomic analysis may help guide whether interventions need to be at hospital discharge or in the community to have the most impact on decreasing CO-HA MRSA infections. Funding: Funding: from CDC Broad Agency Announcement: Genomic Epidemiology of Community-Onset Invasive USA300 MRSA Infections ; Contract ID: 75D30118C02923 Disclosures: None
To evaluate the in vitro effect of varying concentrations of clindamycin on Lactobocillus spp.Concentrations of clindamycin ranging from 1.95-20,000 microg/ml were studied for their effect on the growth of six strains of Lactobacillus.Clindamycin concentrations between 1.95-31.25 microg/ml had no statistically significant effect on growth of lactobacilli (p > 0.05). Concentrations 125 and 250 microg/ml had a bacteriostatic effect. The mean minimum inhibitory concentration (MIC) for studied Lactobacillus strains was determined as 1,000 microg/ml.High concentrations of clindamycin achieved in the vagina by intravaginal application might be inhibitory for Lactobacillus.
