A Community Waterborne Salmonella Bovismorbificans Outbreak in Greece

BACKGROUND

In August 2022, the Hellenic National Public Health Organisation was notified about a gastroenteritis outbreak in town A in Southern Greece. Investigations aimed to identify the source and implement control measures.

METHODS

Case definition categories were used in a 1:3 case-control study. Cases and controls were interviewed about various exposures. Cases' stool samples were cultured on agar plates and characterised by serotyping, antimicrobial susceptibility testing and Pulse Field Gel Electrophoresis (PFGE). Environmental investigations included tap water sampling for microbiological and chemical analysis in town A and inspection of the water supply system.

RESULTS

We identified 33 cases (median age: 17 years). Tap water consumption was the only significant risk factor for gastroenteritis (OR = 5.46, 95% CI = 1.02-53.95). Salmonella (S.) Bovismorbificans isolated from eight stool and one tap water samples had identical PFGE profiles. No resistant isolates were identified. Residual chlorine levels were lower than the acceptable limits before and during the outbreak. We advised consumption of bottled water and adherence to strict hand hygiene rules until tap water was declared suitable for drinking.

CONCLUSIONS

Epidemiological and molecular data revealed a waterborne S. Bovismorbificans outbreak in town A. We recommend local water safety authorities to ensure that residual chlorine levels comply with the legislation towards water safety planning, to mitigate risks.

The routes of hysterectomy: A survey of current practices amongst members of the International Society for Gynaecologic Endoscopy (ISGE)

OBJECTIVE

This study aimed to explore the current opinion on the routes of hysterectomy amongst the members of the International Society for Gynaecologic Endoscopy (ISGE), as well as the perceptions of potential barriers that inhibit gynaecologists from offering a minimally invasive hysterectomies (MIHs) to their patients.

STUDY DESIGN

An anonymous, electronic survey was designed, including the questions about the surgeon location and length of gynaecological practice, preferred approach to hysterectomy, approximate number of surgical cases performed during the year preceding the survey (2021), and potential barriers and contraindications to performing MIHs. It was validated by 12 practicing gynaecologists. Subsequently, the survey was sent to all practicing gynaecologists who are the members of the ISGE.

RESULTS

We received a response from 159 members of ISGE (29 % response rate), of which 92 % with ≥ 5 years in practice since the completion of their residency training in Gynaecology and Obstetrics. When asked about the preferred route of hysterectomy for themselves or their relatives, 59 % chose total laparoscopic hysterectomy (TLH), 19 % vaginal hysterectomy (VH), 8 % chose laparoscopically-assisted vaginal hysterectomy (LAVH) and 5 % chose total abdominal hysterectomy (TAH). However, TAH was the most performed hysterectomy procedure undertaken by the respondents in the year preceding the survey. When asked about the main obstacles to performing MIHs, more than half of the respondents highlighted insufficient training during residency and insufficient surgical experience. Only 25 % of the responders acknowledged reading the ISGE guidelines on performing vaginal hysterectomy.

CONCLUSIONS

Contrary to a full understanding of the benefits of MIHs, lack of training, as well as insufficient surgical experience and unawareness of existing evidence-based guidelines were the main reasons for the high rate of TAH among the ISGE members who participated in the study. All efforts should be directed at teaching VH and TLH techniques during residency, continuous acquisition of practical experience, and use of validated patient selection guidelines for MIH in daily clinical practice.

The impact of obesity on vaginal hysterectomy and laparoscopically-assisted vaginal hysterectomy outcomes: A randomised control trial

OBJECTIVES

This prospective randomised control trial aimed to compare outcome measures of vaginal hysterectomy (VH) and laparoscopically-assisted vaginal hysterectomy (LAVH) in obese vs. non-obese women undergoing hysterectomy for benign uterine conditions with a non-prolapsed uterus. The primary objective of the study was to estimate operation time, uterine weight and blood loss amongst obese and non-obese patients undergoing VH and LAVH. The secondary objective was to determine any difference in hospital stay, the need for post-operative analgesia, intra- and immediate post-operative complications, and the rate of conversion to laparotomy for obese vs. non-obese patients undergoing VH and LAVH.

STUDY DESIGN

A prospective randomised control study was undertaken in the Department of Obstetrics and Gynaecology of the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH). Women admitted between January 2017 and December 2019 for hysterectomy due to benign conditions, meeting the inclusion criteria set by the unit (vaginally accessible uterus, uterine size ≤ 12 weeks of gestation or ≤ 280gr on ultrasound examination, pathology confined to the uterus) were included in the study. The VH procedures were performed by the residents in training, under the supervision of specialists with large experience in vaginal surgery. All the LAVHs were performed by one surgeon (AC). In addition to the patient characteristics and surgical approach to hysterectomy, operative time, estimated blood loss, uterine weight, length of hospital stay, intra-operative and immediate post-operative complications were also recorded in obese and non-obese patient groups and comparatively analysed.

RESULTS

A total of 227 women were included in the study. 151 patients underwent VH and 76 LAVH, upon randomisation on a 2:1 basis, reflecting the habitual proportion of hysterectomy cases in the Urogynaecology and Endoscopy Unit at CMJAH. No significant differences were found in mean shift of pre-operative to post-operative serum haemoglobin, uterine weight, intra- and immediate post-operative complications, and convalescence period when comparing obese and non-obese patients in both the VH and LAVH groups. There was a statistically significant difference in operating time between the two procedures. The LAVHs took longer compared to the VHs to be performed (62.8 ± 9.3 vs. 29.9 ± 6.6 min in non-obese patients, and 62.7 ± 9.8 vs 30.0 ± 6,9 min for obese patients). All VHs and LAVHs were successfully accomplished without major complications.

CONCLUSION

VH and LAVH for the non-prolapsed uterus is a feasible and safe alternative for obese patients demonstrating similar perioperative outcome measures as non-obese women undergoing VH and LAVH. Where possible, VH should be preferred to LAVH as it is a safe route of hysterectomy, with operation time being significantly shorter.

A Point Source Gastroenteritis Outbreak in a High School Putatively Due to Clostridium perfringens: Timely Investigation Is Everything

On May 28, 2021, several gastroenteritis cases were reported among students and staff of a high school on a Greek island. Lunches were delivered daily at the school by a catering company. We conducted a retrospective cohort study. Cases were defined as students or school staff presenting with diarrhea and abdominal pain between May 27 and 29, 2021. We used a self-administered questionnaire to collect the data. In the univariate analysis, we calculated food-specific attack rates (ARs), relative risks (RRs), and confidence intervals (95% CIs). Statistically significant variables (p < 0.05) were included in the multivariable model. Stool samples were collected from students on the same day of notification and were tested for bacteria, viruses, and parasites. The local food safety authority also inspected the school and the catering company premises. The food samples were sent to the reference laboratory for analysis. We received 129 responses from 174 students and staff members (response rate: 74%). Thirty cases were identified (AR, 23%). Of the 11 significant food items in the univariate analysis, the consumption of spaghetti with minced meat on May 27 (odds ratio 53.40, 95% CI: 3.9-736.1, 97% of cases exposed) was independently associated with the onset of gastroenteritis. Clostridium perfringens was detected in two of the three students' stool samples. Six samples from spaghetti with minced meat were positive for C. perfringens and four of those also tested positive for Bacillus cereus. Environmental investigation revealed non-compliances concerning food personnel training and Hazard Analysis and Critical Control Points (HACCP) plan implementation in the food establishment. Timely investigation and samples collection allowed the identification of the probable source of the outbreak. Changes, regarding the reception and distribution of meals in the school, were applied. Recommendations were given to the catering establishment focusing on adequate personnel training and HACCP issues, especially regarding temperature/time controls during all production, handling, and distribution phases.

Public health and clinical implications of multidrug-resistant shigellosis cases in a reception centre for refugees/migrants, Greece, October-December 2019

From October to December 2019, 18 shigellosis cases (median age: 4.3 years, range: 0-21) were identified in the Reception Center for refugees/migrants on the Greek island of Samos. Fifteen cases (83.3%) were Afghani. Median time from arrival to symptoms onset was 53 days (40-101). Isolates from 14 cases, serotyped as Shigella flexneri 1b, and from three cases, serotyped as S. sonnei phase S (I), presented a multidrug-resistant phenotype. S. flexneri 1b isolates also produced extended-spectrum β-lactamases. Shigella flexneri 2a isolate from the remaining case was resistant to sulfomethoxazole, trimethoprim and pefloxacin. Improvement of hygiene and strengthening of laboratory investigation is needed.

Waterborne outbreak in a rural area in Greece during the COVID-19 pandemic: contribution of community pharmacies

INTRODUCTION

On 15 June 2020, the National Public Health Organization was informed about the identification of two cases of Escherichia coli Ο157 infection in a small town in the Peloponnese Region in Greece and we suspected an outbreak.

METHODS

We asked the local pharmacist to assist us to verify the outbreak by providing the daily number of over-the-counter anti-diarrheal drugs sold from 20 May 2020 onwards. The pharmacist asked customers with gastroenteritis to submit stool samples at the local hospital. Samples were tested for 22 pathogens. We conducted a 1 : 1 case-control study. Cases and controls were retrieved from the pharmacy client list. Chlorination records of the water supply system were retrieved, and water samples were tested for microbiological indicators and viruses.

RESULTS

The increased number of sales of anti-diarrheal drugs verified the outbreak. Overall, 58 cases and 57 controls were recruited for the study. Tap water consumption (odds ratio (OR)=10.9, 95% confidence interval (CI)=3.1-38.0, p<0.001) and consumption of ice cubes made from tap water (OR=39.3, 95%CI=10.3-150.9, p<0.001) were independently associated with gastroenteritis occurrence. Eleven stool samples were tested; one was positive for shigatoxin-producing E. coli, one for enteropathogenic E. coli, four for E. coli Ο157 and one for Salmonella spp. Four samples tested negative. Five water samples collected on 18 June tested negative. The residual chlorine on 5 and 14 June ranged from 0.12 mg/L to 0.14 mg/L.

CONCLUSION

This was the first investigation of a waterborne outbreak in Greece performed with the collaboration of a local pharmacy. The COVID-19 pandemic favored the use of alternative resources and channels of communication with the local population, which can also be used in the future, especially in remote areas of the country.

The Rising Burden of Salmonellosis Caused by Monophasic Salmonella Typhimurium (1,4,[5],12:i:-) in Greece and New Food Vehicles

Monophasic Salmonella typhimurium is of increasing importance worldwide. Here we present the available data regarding monophasic S. typhimurium from 2007 to 2019 in Greece, in order to assess its public health impact. Surveillance data, data on antimicrobial resistance, molecular typing by pulsed-field gel electrophoresis (PFGE), and results of the investigation of monophasic S. typhimurium outbreaks were analyzed. Overall, 403 cases were identified; 329 (81.6%) sporadic and 74 (18.4%) related to two community outbreaks in 2017. A total of 305 isolates from sporadic cases tested for antimicrobial resistance revealed resistance to ampicillin, streptomycin, sulphamethoxazole, and tetracycline (41.3%). Some 23.3% were further resistant to trimethoprim and 5.2% were also resistant to chloramphenicol. Outbreak 1 in 2017 with 37 identified cases was attributed to the consumption of raw milk from a vending machine and isolates were resistant to ampicillin, streptomycin, sulphamethoxazole, tetracycline, and trimethoprim. Outbreak 2 also with 37 cases was attributed to the consumption of pork and isolates were resistant to the five above mentioned antibiotics plus chloramphenicol. The number of human monophasic S. typhimurium isolates is low; however, since 2009, it has been among the five most frequently identified serotypes in Greece. Investigation of the outbreaks revealed that other vehicles apart from pork may be implicated in the occurrence of outbreaks.

Impact of Salmonella Control Programmes in Poultry on Human Salmonellosis Burden in Greece

Since 2008, veterinary authorities in Greece have implemented national control programmes (NSCPs) targeting S. Enteritidis (SE) and S. Typhimurium (ST) in poultry. We assessed the effect of the programs on the reported number of human isolates. Using monthly data for 2006–2017, we defined two groups (SE, ST) and one control group with serotypes unrelated to poultry or eggs. For SE we also analysed data for 2006–2015 due to a multi-county SE outbreak in 2016. We performed an interrupted time series analysis and used a negative binominal regression model. For both SE and ST, there was no significant trend of the isolation rate before or after NSCPs’ introduction. After the NSCPs’ introduction there was an increasing rate (IRR: 1.005, 95% CI: 1.001–1.008) for control serotypes and a decreasing one for SE (IRR: 0.990, 95% CI: 0.986–0.995) (for 2009 to 2015 analysis). From 2006 to 2017, NSCPs had a statistically significant impact on the number of SE isolates that decreased by 49% (IRR:0.511, 95% CI: 0.353–0.739). No impact was shown on the number of ST (p-value = 0.741) and control isolates (p = 0.069). As a conclusion, NSCP’s implementation was associated with decreased SE isolates and overall burden of salmonellosis; however further measures aiming at human salmonellosis due to ST, should be considered.

Clostridium perfringens Foodborne Outbreak during an Athletic Event in Northern Greece, June 2019

Background: Food safety is a major public health consideration during athletic events. On 27 June 2019, the Hellenic National Public Health Organization was notified of a cluster of gastroenteritis cases among athletes of four of the 47 teams participating at the Panhellenic Handball Championship for children. Methods: A retrospective cohort study among the members of the four teams was performed. The local public health authority visited the restaurants where common meals took place, amassed information on the preparation of meals, and collected samples of leftovers. Stool samples were tested for Salmonella spp. and Shigella spp. Results: Consumption of minced beef had a statistically significant association with disease occurrence [RR:8.29 (95%CI 1,31-52,7)]. Samples of meat were found positive for Clostridium perfringens. It was documented that the meat was not stored and re-heated as indicated. Stool samples were negative for Salmonella spp. and Shigella spp. and were not tested for the Clostridium perfringens toxin. Conclusion: Specific standards should be kept to prevent outbreaks during athletic events. This was the first time that a foodborne outbreak due to Clostridium perfringens was investigated in the country. Laboratory investigation for toxins should be enhanced, especially in foodborne outbreaks where clinical manifestations of cases are found to be compatible with infection caused by a toxin.

455. Epidemiological Surveillance in Points of Care for Refugees/Migrants: The 2016–2017 Experience in Greece

Background

In 2016 and 2017, 535,000 refugees/migrants crossed the Mediterranean Sea to reach Europe, with 203,000 arriving in Greece. To address enhanced epidemiological surveillance needs, in May 2016 Greece established an ad hoc surveillance system in points of care for refugees/migrants in hosting centers, complementary to routine surveillance.

Methods

Data on number of cases per age group for 14 syndromes of public health (PH) interest were collected daily from primary healthcare units of refugee/migrant hosting centers in the country, along with the number of consultations from any cause. Additional information enabling case-finding was collected for syndromes representing diseases that require PH measures at an individual level. Observed daily proportional morbidity (PM) was compared with expected PM using a quasi-Poisson regression model. PM ≥2 standard deviations from expected was defined as a “warning signal.” “Warning signals” appearing for ≥2 consecutive days were considered “alert signals.” Signals were evaluated daily and public health measures were implemented as necessary.

Results

The number of centers participating in the system ranged between 27 and 51. Mean weekly reporting rate reached 96%. From 16 May 2016 to 31 December 2017, 500,166 consultations from any cause were reported, with 28,300 cases of the syndromes under surveillance (5.6%). Syndromes with the higher PM were respiratory infections with fever (3.3%), gastroenteritis (1.3%), suspected scabies (0.6%), and rash with fever (0.3%, of whom 95.1% were varicella cases, with no measles or rubella identified). Two hundred fifteen cases of suspected tuberculosis were referred to hospitals for further diagnostic testing and treatment. Of 92 cases of jaundice with acute onset, 85% were verified as hepatitis A, triggering interventions such as vaccination. None of the produced signals corresponded to a major PH incident, all being of low severity and duration.

Conclusion

Infections represented a small proportion of refugees’ health problems. Syndromic surveillance in hosting centers guided PH action and confirmed no major PH event.

Disclosures

All authors: No reported disclosures.

2192. Hepatitis A in Greece 2009–2017: Time for Setting New Priorities

Background

The aim of this study was to present the epidemiological data and describe the outbreaks of hepatitis A identified over the period 2009–2017 in Greece.

Methods

Cases recorded through the mandatory notification system were classified in accordance with the European case definition. Data were analyzed by population group (general population, Roma, refugees / migrants, travelers to endemic countries, and MSM).

Results

Between 2009 and 2017, 1,072 cases were reported to the Department of Epidemiological Surveillance and Intervention of the Hellenic Center for Disease Control and Prevention. The median annual number of reported cases was 86 (41–277). Reported cases exceeded the expected number in 2013, 2016 and 2017. In 2013 165 cases were reported [three times higher than the mean annual n reported for 2005–2012; 101 (61.6%) among Roma]. Three clusters were identified accounting for 50% of reported cases. Genotyping showed that clusters were due to hepatitis A virus subgenotype IA. In 2016, after the closure of the northern borders of Greece in March, 177 cases were reported among refugees (subgenotype IB, the majority of affected of Syrian origin). In 2017, an outbreak among men having sex with men (MSM) was recorded as part of a European HAV outbreak. One hundred and seventy-six male cases were recorded (median age; 38 years old, range; 21–55); 81 identified themselves as MSM. Genotyping data showed linkage to identified European clusters (subgenotype IA).

Conclusion

Hepatitis A remains a significant Public Health threat in Greece. Preventive interventions should target populations with low access to healthcare, as well as MSM.

Disclosures

All authors: No reported disclosures.

Urinary B-cell-activating factor of the tumour necrosis factor family (BAFF) in systemic lupus erythematosus

INTRODUCTION

We examined the clinical relevance of urinary concentrations of B-cell-activating factor of the tumour necrosis factor family (BAFF) and a proliferation-inducing ligand (APRIL) in systemic lupus erythematosus (SLE).

METHODS

We quantified urinary BAFF (uBAFF) by enzyme-linked immunosorbent assay in 85 SLE, 28 primary Sjögren syndrome (pSS), 40 immunoglobulin A nephropathy (IgAN) patients and 36 healthy controls (HCs). Urinary APRIL (uAPRIL) and monocyte chemoattractant protein 1 (uMCP-1) were also quantified. Overall and renal SLE disease activity were assessed using the Systemic Lupus Erythematosus Disease Activity Index 2000.

RESULTS

uBAFF was detected in 12% (10/85) of SLE patients, but was undetectable in HCs, IgAN and pSS patients. uBAFF was detectable in 28% (5/18) of SLE patients with active nephritis vs 5/67 (7%) of those without ( p = 0.03), and uBAFF was significantly higher in active renal patients ( p = 0.02) and more likely to be detected in patients with persistently active renal disease. In comparison, uAPRIL and uMCP-1 were detected in 32% (25/77) and 46% (22/48) of SLE patients, respectively. While no difference in proportion of samples with detectable uAPRIL was observed between SLE, HCs and IgAN patients, both uAPRIL and uMCP-1 were significantly detectable in higher proportions of patients with active renal disease.

CONCLUSIONS

uBAFF was detectable in a small but a significant proportion of SLE patients but not in other groups tested, and was higher in SLE patients with active renal disease.

Parents' satisfaction concerning their child's hospital care

AIM

To explore parents' satisfaction concerning their child's care during hospitalization and its determinants.

METHODS

A descriptive, non-experimental correlational design was used. The data collection was based on interviews using a 63 item questionnaire, the Swedish Pyramid Questionnaire. The parents of 206 children (hospitalized in two pediatric and two surgical units) participated in the study.

RESULTS

The independent t-test results demonstrated that the parents showed greater satisfaction with staff attitudes and medical treatment, whereas they were less satisfied with the information concerning routines and the staff work environment. The stepwise multiple regression analysis revealed that adequacy of care, adequate pain management, parents' involvement in care, a trusting relationship, and staff attitudes were the most important determinants of parental satisfaction.

CONCLUSION

Interventions in pediatric care should include measurements of parental and child satisfaction as a tool to assess the quality of care.

Lymphocytic hypophysitis: a rare cause of hypoglycaemia in a man with type 2 diabetes mellitus

Lymphocytic hypophysitis is a primary inflammatory disorder of the pituitary gland, which may cause panhypopituitarism. The majority of cases occur in women during the peripartum period and it is rare in men. We present a case, initially presenting with recurrent hypoglycaemic episodes, in a man with previously well-controlled type 2 diabetes mellitus.

Circular polarisation in star-forming regions: possible implications for homochirality

Our discovery of high degrees of circular polarisation in some star-forming regions provides an attractive mechanism for the origin of homochirality. The largest degrees of circular polarisation, so far observed at near-infrared wavelengths, are thought to arise from the scattering of stellar radiation from aligned dust grains and are calculated to extend down to UV wavelengths. The extent of the region where circularly polarised light (CPL) of a single handedness originates is very large, and it is likely that the whole of a planetary system would see a single handedness of CPL also. We present the observational data, models of the scattering that leads to the production of CPL, and a model for the origin of homochirality. We also discuss briefly future laboratory and space-based experiments.

Detection of Polarized Millimeter and Submillimeter Emission from Sagittarius A*

We report the detection of linear polarization from Sgr A* at 750, 850, 1350, and 2000 µm which confirms the contribution of synchrotron radiation. From the lack of polarization at longer wavelengths, it appears to arise in the millimeter/submillimeter excess. There are large position angle changes between the millimeter and submillimeter results, and these are discussed in terms of a polarized dust contribution in the submillimeter and various synchrotron models. In the model that best explains the data, the synchrotron radiation from the excess is self-absorbed in the millimeter region and becomes optically thin in the submillimeter. This implies that the excess arises in an extremely compact source of approximately 2 Schwarzschild radii.

Submillimeter Polarimetry of the Protostellar Outflow Sources in Serpens with the Submillimeter Common-User Bolometer Array

Submillimeter polarimetric measurements of the 850 µm dust continuum emission associated with the class 0/I protostars in the Serpens dark cloud core are presented. The data are used to infer the magnetic field morphology in the region. Dust grain alignment in accretion flows and/or outflows is also briefly considered. The polarization vectors around the SMM-NW cluster of sources are more ordered than those observed near the SMM-SE cluster. Toward SMM-NW, the vectors are generally orientated north-south; between the intensity peaks in the SMM-SE region, the vectors are approximately east-west. In both regions, we suggest that the polarization pattern may be dictated by a large-scale magnetic field. We consider whether the rough northwest-southeast ridge of submillimeter sources was formed via cloud collapse along field lines that run perpendicular to this ridge. However, our data offer only very tentative support for this hypothesis. We further note that, although overall the polarization pattern in Serpens does not appear to be affected by the many outflows in the region, toward the most luminous source, SMM 1, the source of the Serpens radio jet, the vectors deviate considerably from the general pattern, instead being roughly perpendicular to the flow axis, as one would expect from a B-field oriented parallel with the flow.

Circular polarization in star-formation regions: implications for biomolecular homochirality

Strong infrared circular polarization resulting from dust scattering in reflection nebulae in the Orion OMC-1 star-formation region has been observed. Circular polarization at shorter wavelengths might have been important in inducing chiral asymmetry in interstellar organic molecules that could be subsequently delivered to the early Earth by comets, interplanetary dust particles, or meteors. This could account for the excess of L-amino acids found in the Murchison meteorite and could explain the origin of the homochirality of biological molecules.

Diltiazem in renal allograft recipients receiving cyclosporine

Of 113 cyclosporine-treated primary renal allograft recipients, 60 were randomized to receive standard therapy without diltiazem (ND) and 53 received standard therapy plus diltiazem (D). There was no difference in CsA blood levels between ND and D at all intervals between 3 and 24 months follow-up, yet the D group required 35% less CsA than the ND group (measured at 12 months). At all intervals to 24 months there was no difference in blood pressure, renal function (as measured by serum creatinine), or in the number of grafts lost between the 2 groups (ND, 4 lost; D, 3 lost). There was no significant difference in the total number of rejection episodes in the 2 groups (ND, 89 episodes; D, 71 episodes). However, the severity of rejection episodes was greater in the ND group as evidenced by a significant difference in the usage of OKT3 (ND, 17 courses; D, 8 courses of OKT3, P < 0.05). Of the biopsy-proven episodes of rejection, there were more episodes of vascular rejection in the ND group (ND, 14 episodes; D, 3 episodes, P = 0.005). The incidence of primary nonfunction was less in the D group (ND, 16 patients; D, 5 patients, P = 0.05). It was concluded that the use of diltiazem was associated with a markedly reduced requirement for CsA without any adverse effect on graft function or graft outcome. Diltiazem with CsA was associated with fewer episodes of primary nonfunction and less-severe rejection episodes and in particular fewer episodes of vascular rejection.

Mutation frequency in nurses and pharmacists working with cytotoxic drugs

Individuals occupationally exposed to cytotoxic drugs may be at risk owing to the effects of these agents on DNA. As an index of DNA damage, in vivo mutations were measured in lymphocytes from 24 oncology nurses or pharmacists and 24 matched controls. Mutation frequency was significantly increased in exposed individuals and appeared to be related to duration of exposure. However, the overall magnitude of the increase was small and its biological significance remains to be determined.

Mutation frequency in human lymphocytes increases with age

Several theories of ageing predict that somatic mutations should increase with age. This prediction was tested for human lymphocytes using a recently developed clonal technique for enumeration of mutations, and an increase of 1.6% per year in mutations with age was detected.

Decreased cloning of lymphocytes from elderly individuals

Limiting-dilution cloning of human lymphocytes was used to study cloning and proliferation of lymphocytes in 10 young and 10 elderly individuals. The cloning efficiency for elderly individuals, 3.5%, was significantly lower than that for young individuals, 19.8%. Mixing experiments showed that this decrease was due to both a decrease in the frequency of the clone-forming cells and a decrease in the interacting ability of the lymphocytes. Lymphocytes from elderly individuals which did form clones, however, proliferated at the same rate as did those from young individuals.