Epidemiology and impact of methicillin-sensitive Staphylococcus aureus with ß-lactam antibiotic inoculum effects in adults with cystic fibrosis.

Staphylococcus aureus is the most prevalent cystic fibrosis (CF) pathogen. Several phenotypes are associated with worsened CF clinical outcomes including methicillin-resistance and small-colony-variants. The inoculum effect (IE) is characterized by reduced ß-lactam susceptibility when assessed at high inoculum. The IE associates with worse outcomes in bacteremia and other high-density infections, and may therefore be relevant to CF. The prevalence of IE amongst a CF cohort (age ≥18 years), followed from 2013 to 2016, was investigated. Yearly methicillin-sensitive S. aureus (MSSA) isolates were screened at standard (5 × 105 CFU/mL) and high (5 × 107 CFU/mL) inoculum against narrow-spectrum anti-Staphylococcal ß-lactams and those with anti-pseudomonal activity common to CF. A ≥ 4-fold increase in minimum inhibitory concentration between standard and high inoculum defined IE. Isolates underwent blaZ sequencing and genotyping and were compared against published genomes. Fifty-six percent (99/177) of individuals had MSSA infection. MSSA was observed at ≥105 CFU/mL in 44.8% of entry sputum samples. The prevalence of the IE was 25.0%-cefazolin; 13.5%-cloxacillin; 0%-meropenem; 1.0%-cefepime; 5.2%-ceftazidime; and 34.4%-piperacillin-tazobactam amongst baseline MSSA isolates assessed. blaZ A associated with cefazolin IE (P = 0.0011), whereas blaZ C associated with piperacillin-tazobactam IE (P < 0.0001). Baseline demographics did not reveal specific risk factors for IE-associated infections, nor were long-term outcomes different. Herein, we observed the IE in CF-derived MSSA disproportionally for cefazolin and piperacillin-tazobactam and this phenotype strongly associated with underlying blaZ genotype. The confirmation of CF being a high density infection, and the identification of high prevalence of MSSA with IE in CF supports the need for prospective pulmonary exacerbation treatment studies to understand the impact of this phenotype.

Prevalence and Outcomes of Achromobacter Species Infections in Adults with Cystic Fibrosis: a North American Cohort Study.

Achromobacter species are increasingly being detected in cystic fibrosis (CF) patients, with an unclear epidemiology and impact. We studied a cohort of patients attending a Canadian adult CF clinic who had positive sputum cultures for Achromobacter species in the period from 1984 to 2013. Infection was categorized as transient or persistent (≥50% positive cultures for 1 year). Those with persistent infection were matched 2:1 with age-, sex-, and time-matched controls without a history of Achromobacter infection, and mixed-effects models were used to assess pulmonary exacerbation (PEx) frequency and lung function decline. Isolates from a biobank were retrospectively assessed, identified to the species level by nrdA sequencing, and genotyped using pulsed-field gel electrophoresis (PFGE). Thirty-four patients (11% of those in our clinic), with a median age of 24 years (interquartile range [IQR], 20.3 to 29.8 years), developed Achromobacter infection. Ten patients (29%) developed persistent infection. Persistence did not denote permanence, as most patients ultimately cleared infection, often after years. Patients were more likely to experience PEx at incident isolation than at prior or subsequent visits (odds ratio [OR], 2.7 [95% confidence interval {CI}, 1.2 to 6.7]; P = 0.03). Following persistent infection, there was no difference in annual lung function decline (-1.08% [95% CI, -2.73 to 0.57%] versus -2.74% [95% CI, -4.02 to 1.46%]; P = 0.12) or the odds of PEx (OR, 1.21 [95% CI, 0.45 to 3.28]; P = 0.70). Differential virulence among Achromobacter species was not observed, and no cases of transmission occurred. We demonstrated that incident Achromobacter infection was associated with a greater risk of PEx; however, neither transient nor chronic infection was associated with a worsened long-term prognosis. Large, multicenter studies are needed to clarify the clinical impact, natural history, and transmissibility of Achromobacter.

Development and Validation of a PCR Assay To Detect the Prairie Epidemic Strain of Pseudomonas aeruginosa from Patients with Cystic Fibrosis.

The monitoring of epidemic Pseudomonas aeruginosa is important for cystic fibrosis (CF) infection control. The prairie epidemic strain (PES) is common in western Canadian CF clinics. Using whole-genome sequencing, we identified a novel genomic island and developed a PCR assay for PES. Against a collection of 186 P. aeruginosa isolates, the assay had 98% sensitivity and 100% specificity.

Infection control knowledge, beliefs and behaviours amongst cystic fibrosis patients with epidemic Pseudomonas aeruginosa.

BACKGROUND: Epidemic P. aeruginosa (ePA) infections are common in cystic fibrosis (CF) and have been associated with accelerated clinical decline. Factors associated with ePA are unclear, and evidence based infection control interventions are lacking. METHODS: We prospectively collect all bacterial pathogens from adult CF patients. We performed PA strain typing on retrospectively collected enrollment samples and recent isolates to identify patients infected with ePA. All patients attending our clinic were approached to complete a survey on infection control knowledge, beliefs and exposures. We analyzed responses of those with ePA relative to the entire cohort without ePA as well as those infected with unique strains of P. aeruginosa to assess for risk factors for ePA and differences in infection control knowledge, beliefs or behaviours. RESULTS: Of 144 participants, 30 patients had ePA (two Liverpool epidemic strain, 28 Prairie epidemic strain), 83 % of which had established infection prior to transition to the adult clinic. Risk of concomitant infecting pathogens was no different between groups although, Staphylococcus aureus and non-tuberculous mycobacteria were less common in those with ePA. Patients with ePA were more likely to have attended CF-camp and have a history of CF fundraising. Patients with ePA did not differ with respect to beliefs regarding pathogens or transmission risk, except they believed indirect contact posed little risk. Furthermore, patients with ePA were more likely to continue to associate with others with CF despite extensive counselling. Use of peer-peer online networking was minimal in both groups. CONCLUSION: Infections with ePA are closely linked to past exposures, now routinely discouraged. As socialization is the greatest risk factor for ePA, infection control strategies for ePA must focus on discouraging face-to-face interactions amongst CF patients. As peer support remains a desire amongst patients, investment in technologies and strategies that enable indirect communication and support are required.

Lymphocytes transformed by Epstein-Barr virus. Induction of nuclear antigen reactive with antibody in rheumatoid arthritis.

Sera from approximately two-thirds of patients with rheumatoid arthritis contain an antibody which is reactive with a nuclear antigen present in human B-lymphocyte tissue culture cells. The immunological reaction can be demonstrated by precipitation and immunofluorescence. Evidence is present that the reactive nuclear antigen is associated with Epstein-Barr (EB) virus-transformed lymphocytes. Normal human peripheral blood lymphocytes did not contain the nuclear antigen reactive with rheumatoid arthritis sera, but after infection with EB virus, they showed increasing amounts of reactive nuclear antigen as the cells were transformed into continuous lines. Several established human and simian lymphocyte cell lines known to carry EB viral genomes were shown to contain rheumatoid arthritis-associated nuclear antigen. Evidence is presented which suggests that the rheumatoid arthritis-associated nuclear antigen is different from the previously described EB nuclear antigen.

Clinical Outcomes Associated With Escherichia coli Infections in Adults With Cystic Fibrosis: A Cohort Study.

BACKGROUND: Analysis of "emerging" pathogens in cystic fibrosis (CF) lung disease has focused on unique pathogens that are rare in other human diseases or are drug resistant. Escherichia coli is recovered in the sputum of up to 25% of patients with CF, yet little is known about the epidemiology or clinical impact of infection. METHODS: We studied patients attending a Canadian adult CF clinic who had positive sputum cultures for E coli from 1978 to 2016. Infection was categorized as transient or persistent (≥3 positive sputum cultures, spanning >6 months). Those with persistent infection were matched 2:1 with age, sex, and time-period controls without history of E coli infection, and mixed-effects models were used to assess pulmonary exacerbation (PEx) frequency, lung function decline, hospitalization, and intravenous antibiotic days. RESULTS: Forty-five patients (12.3%) had E coli recovered from sputum samples between 1978 and 2016, and 18 patients (40%) developed persistent infection. Nine patients (24%) had PEx at incident infection, and increased bioburden was predictive of exacerbation (P = .03). Risk factors for persistent infection included lower nutritional status (P < .001) and lower lung function (P = .009), but chronic infection with Pseudomonas aeruginosa was protective. There was no difference in annual lung function decline, need for hospitalization or intravenous antibiotics, or risk of PEx in patients with persistent infection. CONCLUSIONS: Persistent E coli infection was frequent and was more common in CF patients with low nutritional status and lung function. However, this does not predict clinical decline. Multicenter studies would allow better characterization of the epidemiology and clinical impact of E coli infection.

Isolation and characterization of an endogenous type C virus of rhesus monkeys.

A type C retrovirus was isolated from a continuous cell line established from a spontaneous esophageal carcinoma of a rhesus monkey (Macaca mulata) by prolonged cocultivation with canine cells. A DNA transcript of the viral RNA hybridized to a high level and kinetic analysis indicated the presence of multiple copies of the viral genome in rhesus monkey DNA, showing that the virus is endogenous in this species. The rhesus monkey virus closely resembles, in several respects, an endogenous type C virus previously isolated from stumptailed macques (Macaca arctoides), aa species closely related to rhesus monkeys.

Establishment of a cell line with associated Epstein-Barr-like virus from a leukemic orangutan.

An Epstein-Barr virus like herpesvirus has been isolated from a lymphoid cell line derived from an orangutan with spontaneous myelomonocytic leukemia. Herpesvirus has not previously been isolated from this species of higher ape.

Characterization of exogenous type D retrovirus from a fibroma of a macaque with simian AIDS and fibromatosis.

A novel type D retrovirus was isolated by cocultivation of explants of fibromatous tissue from a rhesus monkey (Macaca mulatta) with immunodeficiency and retroperitoneal fibromatosis. This type D virus, isolated from a macaque with simian acquired immunodeficiency syndrome (SAIDS-D/Washington), is exogenous and is partially related to the Mason-Pfizer and the langur monkey type D viruses. The SAiDS-D virus can be distinguished from all other primate retroviruses by antigenicity and molecular hybridization. Nucleic acid hybridization studies reveal that the origin of the SAIDS-D isolate may reside in Old World monkey (subfamily Colobinae) cellular DNA.

A longitudinal characterization of the Non-Cystic Fibrosis Bronchiectasis airway microbiome.

A diverse microbiota exists within the airways of individuals with non-cystic fibrosis bronchiectasis (nCFB). How the lung microbiome evolves over time, and whether changes within the microbiome correlate with future disease progression is not yet known. We assessed the microbial community structure of 133 serial sputa and subsequent disease course of 29 nCFB patients collected over a span of 4-16 years using 16S rRNA paired-end sequencing. Interestingly, no significant shifts in the microbial community of individuals were observed during extended follow-up suggesting the microbiome remains relatively stable over prolonged periods. Samples that were Pseudomonas aeruginosa culture positive displayed markedly different microbial community structures compared to those that were positive for Haemophilus influenzae. Importantly, patients with sputum of lower microbial community diversity were more likely to experience subsequent lung function decline as defined by annual change in ≥-1 FEV1% predicted. Shannon diversity values <1 were more prevalent in patients with FEV1 decline (P = 0.002). However, the relative abundance of particular core microbiota constituents did not associate with risk of decline. Here we present data confirming that the microbiome of nCFB individuals is generally stable, and that microbiome-based measurements may have a prognostic role as biomarkers for nCFB.

The risk of gastrointestinal malignancies in cystic fibrosis: case report of a patient with a near obstructing villous adenoma found on colon cancer screening and Barrett's esophagus.

The life expectancy for cystic fibrosis (CF) patients has increased dramatically over the last 30 years. Although the overall cancer risk for CF patients does not appear to be increased there is a marked increased risk of gastrointestinal malignancies especially in the post lung transplant population. CF patients that do develop gastrointestinal malignancies do so at an earlier age and there is often a lag in the diagnosis and management of these individuals. We present a 39 year old male CF patient that underwent a colonoscopy for colon cancer screening and a large, near obstructing, villous adenoma of his ileum was found. The polyp was removed successfully via endoscopy without incident and there was no evidence of malignancy. An upper endoscopy revealed a long segment of Barrett's esophagus with no evidence of dysplasia. We present this case as well as a detailed review of the literature on cancer risk in CF and a discussion of the mechanisms that may be involved. We also present the risk of GI malignancies in non-CF patients as a guide on how to assess and manage the risk of GI malignancies in this ever-changing patient population.

Depression in lymphocyte response to general mitogens by owl monkeys infected with Herpesvirus saimiri.

The effect of Herpesvirus saimiri (HVS) infection on the response of owl monkey lymphocytes to general mitogens was examined during the development of neoplastic disease. The reactivity of the lymphocytes was then correlated with the clinical condition of the infected monkeys and the content of virus rescued from the peripheral blood lymphocytes (PBL). Eight monkeys developed lymphoma which, in six monkeys, was accompanied by lymphocytic leukemia. All animals that died of HVS-induced neoplasia consistently showed a lack of mitogenic response to phytohemagglutinin and concanavalin A. The response to pokeweed mitogen, while always reduced, was generally less markedly affected than the response to the other two mitogens. Lymphocytes from five of the leukemic animals demonstrated an elevated level of spontaneous DNA synthesis in culture late in the disease. This increased spontaneous DNA synthesis tended to correlate with the rescue of HVS from the PBL as demonstrated by the infective center assay. Although mitogenic hyporesponsiveness corresponded with HVS rescue from PBL in six of nine monkeys, the impairment of normal lymphocyte responsiveness sometimes preceded virus recovery.

Infection of capuchin monkeys (Cebus albifrons) with Herpesvirus saimiri.

Herpesvirus saimiri (HVS) induced persistent, clinically inapparent infections of long-term duration in capuchin monkeys (Cebus albifrons). The infections were characterized by development of antibody to HVS-associated antigens and recovery of low levels of virus-genome-carrying lymphocytes in the peripheral blood. Peripheral lymphocyte counts remained in low-normal to normal ranges and no physical signs of lymphoma were evident. Prednisolone treatment caused immunosuppression in one monkey; this was accompanied by a progressive loss of humoral antibody to HVS-associated antigens, but neoplastic disease did not develop.

Spontaneous lymphoma associated with Herpesvirus saimiri in owl monkeys.

Two cases of lymphoma and one case of lymphoproliferative disease were found in a group of 7 owl monkeys imported into our colony as a single group. Herpesvirus saimiri (HVS) was isolated from the tumor cells of 1 lymphoma by cocultivation and from kidney cell cultures from the monkey with lymphoproliferative disease. Antibody to HVS was found in serum samples from 2 monkeys positive for HVS but not in the sera from the 4 clinically normal monkeys. Antibody to Epstein-Barr virus-infected cells was also found in the serum from the animal with lymphoma.

Chronic Herpesvirus saimiri infection in an owl monkey.

An adult owl monkey (Aotus tricirgatus) used for immunologic studies of Herpesvirus saimiri (HVS) developed early, late, membrane, and neutralizing antibodies to HVS approximately 3 weeks after the beginning of the experiment. HVS was isolated by the cocultivation of peripheral blood for over 1 year. No clinical, gross, or histopathologic findings of malignancy were exhibited by the animal. The HVS isolate from the animal was indistinguishable biologically and serologically from the original HVS strain of Meléndez and from an isolate of an experimentally HVS-induced tumor. Inoculation of this isolate into 2 young white-lipped marmosets (Saguinus fuscicollis) produced typical malignant lymphoma and lymphocytic leukemia. Our findings suggested that the virus from the chronically infected animal was oncogenic and that host factors were primarily responsible for determining the disease manifestation of the virus infection. Another owl monkey chronically infected with HVS for over 2 years has remained asymptomatic.

Pilot studies with human interferon in Herpesvirus saimiri-induced lymphoma in owl monkeys.

The nature of Herpesvirus saimiri-induced disease in owl monkeys is described with emphasis on those biological parameters useful in monitoring the disease. These parameters are lymphocyte response to general mitogens, lymphocyte-infective centers, and antibody to virus-associated early antigen. Human interferon was used in treating owl monkeys with virus-induced leukemia. In 2 animals evidence was obtained that suggested a positive antileukemic effect.

Spontaneous esophageal carcinoma and epithelial cell line of an adult rhesus monkey.

A continuous epithelial cell line, 816A, was established from a lymph node of an adult rhesus monkey with metastatic esophageal carcinoma. These cells are characterized by the presence of desmosomes and a markedly heteroploid karyotype. At a relatively early culture age, electron microscopy showed both budding and extracellular type C virus. Antigen reactive with antisera to Mason-Pfizer monkey virus was observed by complement-fixation. The level of this antigen decreased with increased culture age. To our knowledge, the 816A cells represent the only established simian or human cell line of esophageal carcinoma origin.

Distribution and immunochemical characterization of a keratin-like antigen in epithelial tumors using mouse and human monoclonal antibodies.

Using conventional murine hybridoma technology, we have produced a monoclonal antibody (MAb), 89E5, which recognizes two keratin-like polypeptides (Mr 53,000 and 45,000), which are preferentially expressed by epithelial tumors. In addition to detection of tumor cells by immunohistochemistry, MAb 89E5 was able to localize to tumor xenografts in nude mice after iodination of its F(ab')2 fragments. To develop potentially less immunogenic antibodies to antigens defined by MAb 89E5, studies were performed to produce a human counterpart to the mouse MAb. The mouse 89E5 MAb was used to purify the 89E5 polypeptides from tumor cell lines. The partially purified 89E5 antigen was then used to sensitize human splenic lymphocytes in vitro. Immortalization of the sensitized cells by cell fusion resulted in a human IgM MAb, PA1, which showed the same reactivity pattern on a panel of cell lines as did the mouse MAb 89E5. Immunofluorescent studies showed that both 89E5 and PA1 had staining patterns on epithelial cells indicative of antibodies to cytokeratin. Furthermore, PA1 immunoprecipitated two polypeptides (Mr 53,000 and 45,000) which comigrated with the 89E5 polypeptides. Competitive binding assays showed that the PA1 MAb and 89E5 MAb recognized closely associated epitopes. As with the 89E5 MAb, PA1 was reactive with tumor tissues in immunohistochemical studies. These studies indicate that the PA1 MAb is a human counterpart of the mouse 89E5 MAb. Direct comparison of human MAb and mouse MAb against the same antigen could yield valuable information on the efficacy of using human MAb in vivo.

Tissue distribution, immunochemical characterization, and biosynthesis of 47D10, a tumor-associated surface glycoprotein.

This report describes a new monoclonal antibody (MAb) designated 47D10 which was produced by immunizing mice against a human lung adenocarcinoma line, A549. The MAb 47D10 reacts with a surface antigen found in 95% of adenocarcinomas of the pancreas as well as on high percentages of adenocarcinomas from colon, breast, lung, and bile duct. The antigen was not detected in normal pancreas, in pancreatitis, or in a variety of normal tissues with the exception of colon and mature granulocytes. Lymphocytes and erythrocytes were also negative. The binding of 47D10 to tumor cells was unaffected by treatment of cells with neuraminidase. Immunoprecipitation followed by polyacrylamide gel electrophoresis showed that 47D10 MAb recognized a group of glycoproteins ranging in molecular weight from 67,000-98,000 on A549 lung carcinoma cells. Pulse-chase labeling showed two precursor proteins with molecular weights of 69,000 and 67,000 which were processed to the larger polypeptides in 1.5 h. At least part of the carbohydrates associated with the 47D10 antigen was asparagine linked because the antigen was sensitive to endoglycosidases, and tunicamycin inhibited the biosynthesis of 47D10 antigen. The 47D10 antigen was expressed on the cell surface because it could be detected on live A549 cells by enzyme-linked immunosorbant assays as well as by immunofluorescent staining. Furthermore, 47D10 antigens on tumor cell lines and granulocytes were vectorially labeled with 125I. The antigen found on granulocytes showed a higher molecular weight of 150,000-180,000, which was digested by endoglycosidase F to polypeptides with molecular weights ranging from 23,000-27,000. In contrast, the degradation product of the A549 antigen was a Mr 39,000 polypeptide after treatment with endoglycosidase F. The immunochemical characteristics of 47D10 antigen suggest that it is distinct from other antigens associated with pancreatic tumors, such as carcinoembryonic antigen, 19-9, and Du-PAN-2. By virtue of its broad range of tumor cell reactivity and low activity on normal cells, the 47D10 MAb may represent an important immunological reagent for differential diagnosis, especially of pancreatic carcinoma.

The proliferation and function of human mononuclear leukocytes and natural killer cells in serum-free medium.

We recently developed a serum-free (SF) culture medium that supports the growth of several established lymphoid cell lines. In an effort to develop a standardized medium for assay of human natural killer (NK) cell activity, we compared the cytotoxic activity of peripheral blood mononuclear leukocytes (PBL) and purified large granular lymphocytes (LGL) cultured in SF medium containing interleukin 2 (IL-2) or medium containing 10% fetal bovine serum (FBS) plus IL-2. The results indicated that PBL had a 30% increase in cumulative net cell growth and had as high or higher cytotoxic activity after growth in SF medium than in medium containing FBS. Purified LGL had a 50% increase in cumulative net cell growth and persisted approximately 2 weeks longer in culture in medium containing FBS than in SF medium. However, the cytotoxic activity of cells grown in SF medium persisted during the initial 3 weeks of culture. Purified LGL that were maintained and were subcultured at cell densities of 10(6) cells or greater per milliliter of either SF or FBS-containing medium had equivalent levels of cytotoxicity over a 44-day period in either medium compared with cells subcultured at a density of 5 X 10(5) cells per milliliter of medium. NK cells produced a cytotoxic factor (NKCF) in SF medium, and its cytotoxic activity was blocked by 10% FBS. We conclude that the SF medium supplemented with IL-2 can be used as an alternative to FBS-containing medium with IL-2 for the growth of NK cells and is advantageous for the production of NKCF.