Important Reservoir For Transmission Research Articles

Pneumococcal carriage and disease in adults in England 2011-2019: the importance of adults as a reservoir for pneumococcus in communities.

Pneumococcal carriage in children has been extensively studied, but carriage in healthy adults and its relationship to invasive pneumococcal disease (IPD) is less understood. Nasal wash samples from adults without close contact with young children (Liverpool, UK), 2011-2019, were cultured, and culture-negative samples tested by PCR. Pneumococcal carriage in adults 18-44 years was compared with carriage among PCV-vaccinated children 13-48 months (nasopharyngeal swabs, Thames Valley, UK) and IPD data for England for the same ages for 2014-2019. Age-group specific serotype invasiveness was calculated and used with national IPD data to estimate carriage serotype distributions for adults aged 65+ years. In total 98 isolates (97 carriers) were identified from 1,631 adults aged 18+ years (age and sex standardized carriage prevalence 6.4%), with only three identified solely by PCR. Despite different carriage and IPD serotype distributions between adults and children, serotype invasiveness was highly correlated (R=0.9). Serotypes 3, 37 and 8 represented a higher proportion of adult carriage than expected from direct low-level transmission from children to adults. The predicted carriage serotype distributions for 65+ years aligned more closely with the carriage serotype distribution for young adults than young children. The nasal wash technique is highly sensitive; additional benefit of PCR is limited. Comparison of carriage serotype distributions suggests some serotypes may be circulating preferentially within these specific young adults. Our data suggest that for some serotypes carried by adults 65+ years, other adults may be an important reservoir for transmission. Age groups such as older children should also be considered.

Molecular Epidemiology genes detection of Klebsiella pneumoniae Clinical Isolates from the Adult Patients with Comorbidities in Baghdad hospitals

Background Klebsiella species is one of the most worldwide opportunistic pathogens in the world that cause infections at multiple sites like lung, urinary tract, bloodstream, wound or surgical site, and brain. Klebsiella pneumoniae has many types of virulence factors that give the bacteria the ability to invade the host and cause infections. Methods A total of (105) human clinical samples were collected from different patients with different cases. Klebsiella pneumonia were isolated from 30 samples. The bacteria were identified by biochemical tests and certified by using VITEK 2 system and genetically by amplify using PCR for 16 rRNA gene. One of the Klebsiella pneumoniae virulence factors is the capsule that is responsible for the macrophage resistance and its also responsible for serotype. So to confirm the strains isolated, PCR Gene detection of, MagA, K2A, RmpA, and Kfu, where (magA, k2A, rmpA, kfu) gens are responsible for capsule synthesis of Klebsiella pneumonia have been done. Results There were 30 strains of Klebsiella pneumoniae were identified. Epidemiological studies show that infections are preceded by gastrointestinal colonization, with the gastrointestinal tract being the most important reservoir for transmission. The primary bacterial isolates were identified based on their cultural, microscopic, and biochemical traits. The API system (API 20E) and VITEK 2 systems were used to confirm the identity of the bacterial isolates. Colony morphology revealed that Klebsiella pneumonia was Gram-negative, non-motile, microscopic straight rods grouped singly or in pairs. Biochemical tests showed that neutral end products prevailed over acidic end products, with Klebsiella producing negative results for indole. The Kligler Iron Agar (KIA) test showed that Klebsiella isolates changed the color of the slant and butt, producing an acidic slant and acid butt, along with gas production. The urease test for Klebsiella distinguishes between Enterobacter and Klebsiella isolates, as Klebsiella can manufacture the urease enzyme. The indole test distinguishes K. pneumonia from K. pneumonia from K. mobiliz. The API 20E system was used for biochemical testing, and the VITEK 2 system was used for identification. The VITEK 2 system was used to test for biochemical and antibiotic susceptibility, and the results supported the findings from morphological and biochemical analyses. PCR amplification was used for molecular detection, and all nine isolates tested positive for the magA and k2A genes. The ferric iron uptake system gene (kfu) and the extracapsular polysaccharide synthesis regulator gene (rmpA) were amplified using specific primer pairs. The VITEK 2 system demonstrated promising outcomes for K. pneumoniae identification. However, standard diagnostic methods are costly and time-consuming. Conclusions Navigating the complex landscape of infectious diseases, collaborative research projects have become indispensable in unraveling the mysteries surrounding pathogens. The project in Baghdad, having stood as a shining example of such collaboration, provided valuable insights into the identification, characterization, and molecular aspects of Klebsiella pneumoniae strains. The findings, have not only contributed to the scientific community's understanding of bacterial infections but also paved the way for enhanced strategies in diagnosis and treatment.

Seroprevalence, Risk Factors, and Rodent Reservoirs of Leptospirosis in an Urban Community of Puerto Rico, 2015.

The burden of leptospirosis in Puerto Rico remains unclear due to underreporting. A cross-sectional survey and rodent trapping was performed in a community within San Juan, Puerto Rico to determine the seroprevalence and risk factors for Leptospira infection. The microscopic agglutination test was used to detect anti-Leptospira antibodies as a marker of previous infection. We evaluated Leptospira carriage by quantitative polymerase chain reaction among rodents trapped at the community site. Of 202 study participants, 55 (27.2%) had Leptospira agglutinating antibodies. Among the 55 seropositive individuals, antibodies were directed most frequently against serogroups Icterohaemorrhagiae (22.0%) and Autumnalis (10.6%). Of 18 captured rodents, 11 (61.1%) carried pathogenic Leptospira (Leptospira borgpetersenii, 7 and Leptospira interrogans, 2). Four participants showed their highest titer against an isolate obtained from a rodent (serogroup Ballum). Increasing household distance to the canal that runs through the community was associated with decreased risk of infection (odds ratio = 0.934 per 10-meter increase; 95% confidence interval, .952-.992). There are high levels of Leptospira exposure in an urban setting in Puerto Rico, for which rodents may be an important reservoir for transmission. Our findings indicate that prevention should focus on mitigating risk posed by infrastructure deficiencies such as the canal.

Inter-sectoral approaches for the prevention and control of malaria among the mobile and migrant populations: a scoping review

BackgroundMalaria cases among mobile and migrant populations (MMPs) represent a large and important reservoir for transmission, if undetected or untreated. The objectives of this review were to identify which intersectoral actions have been taken and how they are applied to interventions targeted at the MMPs and also to assess the effect of interventions targeted to these special groups of population.ResultsA total of 36 studies met the inclusion criteria for this review. Numerous stakeholders were identified as involved in the intersectoral actions to defeat malaria amongst MMPs. Almost all studies discussed the involvement of Ministry of Health/Public Health (MOH/MOPH). The most frequently assessed intervention among the studies that were included was the coverage and utilization of insecticide-treated nets as personal protective measures (40.5%), followed by the intervention of early diagnoses and treatment of malaria (33.3%), the surveillance and response activities (13.9%) and the behaviour change communication (8.3%). There is a dearth of information on how these stakeholders shared roles and responsibilities for implementation, and about the channels of communication between-and-within the partners and with the MOH/MOPH. Despite limited details in the studies, the intermediate outcomes showed some evidence that the intersectoral collaborations contributed to improvement in knowledge about malaria, initiation and promotion of bed nets utilization, increased access to diagnosis and treatment in a surveillance context and contributed towards a reduction in malaria transmission. Overall, a high proportion of the targeted MMPs was equipped with correct knowledge about malaria transmission (70%, 95% CI 57–83%). Interventions targeting the use of bed nets utilization were two times more likely to reduce malaria incidence amongst the targeted MMPs (summary OR 2.01, 95% CI 1.43–2.6) than the non-users. The various intersectoral actions were often more vertically organized and not fully integrated in a systemic way within a given country or sub-national administrative setting.ConclusionFindings suggest that interventions supported by the multiple stakeholders had a significant impact on the reduction of malaria transmission amongst the targeted MMPs. Well-designed studies from different countries are recommended to robustly assess the role of intersectoral interventions targeted to MMPs and their impact on the reduction of transmission.

A hospital-based matched case-control study to identify risk factors for clinical infection with OXA-48-producing Klebsiella pneumoniae in rectal carriers.

Asymptomatic colonisation of the gastrointestinal tract by carbapenemase-producing Enterobacteriaceae is an important reservoir for transmission, which may precede infection. This retrospective observational case-control study was designed to identify risk factors for developing clinical infection with OXA-48-producing Klebsiella pneumoniae in rectal carriers during hospitalisation. Case patients (n = 76) had carbapenemase-producing K. pneumoniae (CPKP) infection and positive rectal culture for CPKP. Control patients (n = 174) were those with rectal colonisation with CPKP but without CPKP infection. Multivariate analysis identified the presence of a central venous catheter (OR 4·38; 95% CI 2·27-8·42; P = 0·008), the number of transfers between hospital units (OR 1·27; 95% CI (1·06-1·52); P < 0·001) and time at risk (OR 1·02 95% CI 1·01-1·03; P = 0·01) as independent risk factors for CPKP infection in rectal carriers. Awareness of these risk factors may help to identify patients at higher risk of developing CPKP infection.

Mosquito behaviour change after distribution of bednets results in decreased protection against malaria exposure

Background.Behavioral resilience in mosquitoes poses a significant challenge to mosquito control. Although behavior changes in anopheline vectors have been reported over the last decade, there are no empirical data to suggest they compromise the efficacy of vector control in reducing malaria transmission.Methods.In this study, we quantified human exposure to both bites and infective bites of a major malaria vector in Papua New Guinea over the course of 4 years surrounding nationwide bednet distribution. We also quantified malaria infection prevalence in the human population during the same time period.Results.We observed a shift in mosquito biting to earlier hours of the evening, before individuals are indoors and protected by bednets, followed by a return to preintervention biting rates. As a result, net users and non–net users experienced higher levels of transmission than before the intervention. The personal protection provided by a bednet decreased over the study period and was lowest in the adult population, who may be an important reservoir for transmission. Malaria prevalence decreased in only 1 of 3 study villages after the distribution.Discussion.This study highlights the necessity of validating and deploying vector control measures targeting outdoor exposure to control and eliminate malaria.

Meticillin-resistant Staphylococcus aureus (MRSA) acquisition risk in an endemic neonatal intensive care unit with an active surveillance culture and decolonization programme

Meticillin-resistant Staphylococcus aureus (MRSA) is a leading cause of healthcare-associated infection in the neonatal intensive care unit (NICU). Decolonization may eliminate bacterial reservoirs that drive MRSA transmission. To measure the association between colonization pressure from decolonized and non-decolonized neonates and MRSA acquisition to inform use of this strategy for control of endemic MRSA. An eight-year retrospective cohort study was conducted in a level-4 NICU that used active surveillance cultures and decolonization for MRSA control. Weekly colonization pressure exposures were defined as the number of patient-days of concurrent admission with treated (decolonized) and untreated (non-decolonized) MRSA carriers in the preceding seven days. Poisson regression was used to estimate risk of incident MRSA colonization associated with colonization pressure exposures. The population-attributable fraction was calculated to assess the proportion of overall unit MRSA incidence attributable to treated or untreated patients in this setting. Every person-day increase in exposure to an untreated MRSA carrier was associated with a 6% increase in MRSA acquisition risk [relative risk (RR): 1.06; 95% confidence interval (CI): 1.01-1.11]. Risk of acquisition was not influenced by exposure to treated, isolated MRSA carriers (RR: 1.01; 95% CI: 0.98-1.04). In the context of this MRSA control programme, 22% (95% CI: 4.0-37) of MRSA acquisition could be attributed to exposures to untreated MRSA carriers. Untreated MRSA carriers were an important reservoir for transmission. Decolonized patients on contact isolation posed no detectable transmission threat, supporting the hypothesis that decolonization may reduce patient-to-patient transmission. Non-patient reservoirs may contribute to unit MRSA acquisition and require further investigation.

Risk factors associated with carbapenemase-producing Klebsiella pneumoniae fecal carriage: A case-control study in a Spanish tertiary care hospital.

Asymptomatic colonization of the gastrointestinal tract by carbapenemase-producing Enterobacteriaceae is an important reservoir for transmission that may precede infection. This prospective, observational, case-control study was designed to identify risk factors for carbapenemase-producing Klebsiella pneumoniae (CPKP) fecal carriage. This study included 87 cases and 200 controls. Multivariate analysis identified length of stay (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.01-1.03; P = .03), previous hospitalization (OR, 5.89; 95% CI, 1.73-20.68; P = .01), antibiotic use (OR, 0.20; 95% CI, 0.65-0.62; P = .01), and corticosteroid use (OR, 0.33; 95% CI, 0.15-0.74; P = .007) as independent risk factors for CPKP rectal carriage. Length of hospital stay, previous hospitalization, corticosteroid use, and antimicrobial exposure are important risk factors for CPKP rectal colonization. Adherence to infection control practices and directed surveillance programs appear to be critical components for CPKP control programs.

Persistently Infected Horses Are Reservoirs for Intrastadial Tick-Borne Transmission of the Apicomplexan Parasite Babesia equi

Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected ticks developed levels of > or =10(4) organisms/pair of salivary glands independent of the level of parasitemia during acquisition feeding and successfully transmitted them, indicating that replication within the tick compensated for any initial differences in infectious dose and exceeded the threshold for transmission. During the development of B. equi parasites in the salivary gland granular acini, the parasites expressed levels of paralogous surface proteins significantly different from those expressed by intraerythrocytic parasites from the mammalian host. In contrast to the successful intrastadial transmission, adult female R. microplus ticks that fed on horses with high parasitemia passed the parasite vertically into the eggs with low efficiency, and the subsequent generation (larvae, nymphs, and adults) failed to transmit B. equi parasites to naïve horses. The data demonstrated that intrastadial but not transovarial transmission is an efficient mode for B. equi transmission and that persistently infected horses are an important reservoir for transmission. Consequently, R. microplus male ticks and persistently infected horses should be targeted for disease control.

Persistent environmental reservoirs for Vancomycin-resistant enterococci requiring repeated decontamination to achieve eradication

V ancomycin-resistant enterococci (VRE) are increasingly recognised nosocomial pathogens in clinical areas with high antibiotic usage. Patients with chronic renal failure, including those requiring haemodialysis, are at particular risk. Investigation and control of an outbreak of VRE in two renal wards, highlighting mattresses as reservoirs and environmental measures to control VRE are reported in this paper. Outbreak control measures included standard isolation in accordance with the Recommendations of the Hospital Infection Control Practices Advisory Committee (HICPAC). Patients were screened on admission and weekly using a rectal swab. The inanimate environment including mattresses was also screened. Enhanced environmental decontamination was performed on a daily basis. The outbreak continued over a 20-week period with most cases occurring in the first 6 weeks. The results of screening indicated that 59 (13%) of 451 patients and 54 (8.3%) of 647 environmental samples were positive for VRE. VRE was isolated from 35 (8%) of 433 mattresses, 12 (8.1%) of 148 environmental ledges, 4 (8%) of 50 toilets, and 3 (18.8%) of 16 items of cleaning equipment. Molecular typing indicated that a predominant strain was also implicated in mattress contamination, thus highlighting a potential and important reservoir for transmission of VRE. Difficulty with eradication of VRE from the environment was encountered despite enhanced cleaning regimens and a doubling of use of disinfectant was necessary. Restriction of antibiotics, hand hygiene, hygiene and education are the cornerstone of VRE prevention and control. Lessons from this outbreak highlight the role of the environment in VRE transmission and the need for attention to the environment, especially mattress decontamination.