- Volume 70, Issue 1, 2021
Volume 70, Issue 1, 2021
- Review
-
-
-
Understanding the microbial components of periodontal diseases and periodontal treatment-induced microbiological shifts
More LessIn the mid-1960s the microbial aetiology of periodontal diseases was introduced based on classical experimental gingivitis studies . Since then, numerous studies have addressed the fundamental role that oral microbiota plays in the initiation and progression of periodontal diseases. Recent advances in laboratory identification techniques have contributed to a better understanding of the complexity of the oral microbiome in both health and disease. Modern culture-independent methods such as human oral microbial identification microarray and next-generation sequencing have been used to identify a wide variety of microbial taxa residing in the gingival sulcus and the periodontal pocket. The first theory of the ‘non-specific plaque’ hypothesis gave rise to the ‘ecological plaque’ hypothesis and more recently to the ‘polymicrobial synergy and dysbiosis hypothesis’. Periodontitis is now considered to be a multimicrobial inflammatory disease in which the various bacterial species within the dental biofilm are in a dysbiotic state and this imbalance favours the establishment of chronic inflammatory conditions and ultimately the destruction of tooth-supporting tissues. Apart from the known putative periodontal pathogens, the whole biofilm community is now considered to play a role in the establishment of inflammation and the initiation and progression of periodontitis in a susceptible host. Treatment is unlikely to eliminate putative pathogens but, when it is thoroughly performed it has the potential to establish a healthy ecosystem by altering the microbial community in numbers and composition and also contribute to the maturation of the host immune response.
-
-
- Antimicrobial Resistance
-
-
-
Emergence of ciprofloxacin-resistant Neisseria meningitidis B from asymptomatic carriers during an outbreak in Peru, 2017
Asymptomatic carriers are a likely source of transmission of Neisseria meningitidis to close contacts who are placed at a higher risk for invasive meningococcal disease (IMD). Although N. meningitidis ciprofloxacin-resistance is rare, there have been an increase in the reports of resistant isolates mainly in patients diagnosed with IMD, and little is known about the N. meningitidis ciprofloxacin-resistance in the carrier populations. We performed a pharyngeal carriage study during a 2017 military setting outbreak in Peru, caused by a ciprofloxacin-resistant N. meningitidis B. The isolates analysed came from two hospitalized cases and six asymptomatic carriers. Whole-genome sequence-based analysis was performed and showed that strains carrying the Thr91Ile mutation, in the gene encoding for subunit A of DNA gyrase (gyrA), were responsible for the fluoroquinolone resistance (MICs ≥0.256 µg ml−1) and were closely related to highly virulent strains from France, Norway and the UK. Phylogenetic analysis of the gyrA gene revealed that likely these Peruvian isolates acquired resistance through horizontal gene transfer from Neisseria lactamica . Our study provides evidence for the emergence and propagation of ciprofloxacin-resistant N. meningitidis B from asymptomatic carriers, and recommends the introduction of serogroup B vaccines for high-risk populations.
-
-
-
-
Gram-negative bacilli bacteremia: a 7 year retrospective study in a referral Brazilian tertiary-care teaching hospital
Introduction. Bloodstream infection is one of the most frequent and challenging hospital-acquired infections and it is associated with high morbidity, mortality and additional use of healthcare resources.
Hypothesis/Gap Statement: Bloodstream infections have consequences for the patient, such as the evolution to mortality and inappropriate empirical antibiotic prescription, especially when caused by multidrug-resistant Gram-negative bacilli.
Objective. To assess the impact of bloodstream infection and the status of multidrug resistance (MDR) in the evolution of patients who received inappropriate initial antibiotic therapy.
Methods. A retrospective surveillance was conducted on nosocomial bloodstream infections caused by Gram-negative bacilli (GNB) from January 2012 to December 2018 in an adult intensive care unit of a Brazilian tertiary teaching hospital.
Results. We identified 270 patients with GNB nosocomial bacteremia. Non-survivors were older (with an average age of 58.8 years vs 46.9 years, P=<0.0001), presented more severe illnesses, were immunosuppressed (73.7 vs 37.6%, P=<0.0001), were more likely to have septic shock (55.8 vs 22.4%, P=<0.0001) and had an increased usage of mechanical ventilators (98.6 vs 89.6%, P=0.0013) than survivors. In a logistic regression model, inappropriate empirical antibiotic therapy was not an independent predictor of mortality, different from mechanical ventilator (P=<0.0001; OR=28.0; 95% CI=6.3–123.6), septic shock (P=0.0051; OR=2.5; 95% CI=1.3–4.9) and immunosuppression (P=0.0066; OR=2.6; 95% CI=1.3–5.2). In contrast, in a separate model, MDR was strongly associated with the prescription of inappropriate initial antibiotic therapy (P=0.0030; OR=5.3; 95% CI=1.7–16.1). The main isolated pathogens were Acinetobacter baumannii (23.6 %) and Klebsiella pneumoniae (18.7 %). The frequency of MDR organisms was high (63.7 %), especially among non-fermenting bacilli (60.9 %), highlighting A. baumannii (81.6 %) and Pseudomonas aeruginosa (41.8 %).
Conclusion. Illness severity (septic shock and immunosuppression) and mechanical ventilation were identified as predictors of mortality. Additionally, MDR was a major determinant of inappropriate antibiotic empirical therapy, but not associated with mortality, and both characteristics were not statistically associated with death.
-
- Clinical Microbiology
-
-
-
Paediatric bacterial meningitis in the USA: outcomes and healthcare resource utilization of nosocomial versus community-acquired infection
Introduction. Paediatric bacterial meningitis remains a costly disease, both financially and clinically.
Hypothesis/Gap Statement. Previous epidemiological and cost studies of bacterial meningitis (BM) have largely focused on adult populations or single pathogens. There have been few recent, large-scale studies of pediatric BM in the USA.
Aim. We examined healthcare resource utilization (HCRU) and associated morbidity and mortality of community-acquired versus nosocomial bacterial infections in children across the USA.
Methodology. The IBM MarketScan Research databases were used to identify patients <18 years old admitted to USA hospitals from 2008 to 2015 with a primary diagnosis of BM. Cases were categorized as either community-acquired or nosocomial. HCRU, post-diagnosis neurosurgical procedures, 30-day in-hospital mortality, and complications were compared between groups. Multivariable regression adjusted for sex, age and Gram staining was used to compare costs of nosocomial versus community-acquired infections over time.
Results. We identified 1928 cases of paediatric BM without prior head trauma or neurological/systemic complications. Of these, 15.4 % were nosocomial and 84.6 % were community-acquired infections. After diagnostic lumbar puncture (37.1 %), the most common neurosurgical procedure was placement of ventricular catheter (12.6 %). The 30-day complication rates for nosocomial and community-acquired infections were 40.5 and 45.9 %, respectively. The most common complications were hydrocephalus (20.8 %), intracranial abscess (8.8 %) and cerebral oedema (8.1 %). The 30-day in-hospital mortality rates for nosocomial and community-acquired infections were 2.7 and 2.8 %, respectively.
Median length of admission was 14.0 days (Q1: 7 days, Q3: 26 days). Median 90-day cost was $40 861 (Q1: $11 988, Q3: $114,499) for the nosocomial group and $56 569 (Q1: $26 127, Q3: $142 780) for the community-acquired group. In multivariable regression, the 90-day post-diagnosis total costs were comparable between groups (cost ratio: 0.89; 95 % CI: 0.70 to 1.13), but at 2 years post-diagnosis, the nosocomial group was associated with 137 % higher costs (CR: 2.37, 95 % CI: 1.51 to 3.70).
Conclusion. In multivariable analysis, nosocomial infections were associated with significantly higher long-term costs up to 2 years post-infection. Hydrocephalus, intracranial epidural abscess and cerebral oedema were the most common complications, and lumbar punctures and ventricular catheter placement were the most common neurosurgical procedures. This study represents the first nation-wide, longitudinal comparison of the outcomes and considerable HCRU of nosocomial versus community-acquired paediatric BM, including characterization of complications and procedures contributing to the high costs of these infections.
-
-
- Disease, Diagnosis and Diagnostics
-
-
-
The clinical significance of simultaneous detection of pathogens from bronchoalveolar lavage fluid and blood samples by metagenomic next-generation sequencing in patients with severe pneumonia
Introduction. Bloodstream infection is a common complication in patients with severe pneumonia and is regarded as an independent risk factor for prediction of poor outcome. Metagenomic next-generation sequencing (mNGS) has been widely applied for pathogen determination of various clinical specimens from patients with infectious diseases. However, the clinical significance of and necessity for simultaneous pathogen detection of both blood samples and bronchoalveolar lavage fluid (BALF) by mNGS in patients with severe pneumonia remains unclear.
Hypothesis/Gap Statement. Simultaneous detection of pathogens from both BALF and blood samples in patients with severe pneumonia helps to determine the complication of the bloodstream infection.
Aims. This study aimed to elucidate the clinical significance and necessity of pathogen detection simultaneously in both blood samples and BALF samples with the application of mNGS in patients with severe pneumonia.
Methods. In this study, 20 patients with severe pneumonia were enrolled and the potential pathogens in both BALF and blood samples were detected simultaneously by conventional microbial examination and mNGS tests. Moreover, multiple consecutive microbial detections were undertaken to investigate the dynamic variation of pathogens during the course of disease progression in two of the 20 patients.
Results. In 85 % (17/20) of the patients with severe pneumonia, various pathogens were determined positively in the BALF by mNGS, including 10 cases with bacterial infection, five cases with viral infection and two cases with fungal infection. By contrast, pathogens in 50 % (10/20) of cases could be detected positively in the BALF by conventional microbial tests. Among 17 severe pneumonia patients with mNGS-positive BALF, pathogens were also identified in 10 cases with mNGS-positive blood samples. By contrast, only one patient complicated with a bloodstream infection could be found by conventional bacterial culture. Moreover, the pathogens from BALF were highly consistent with that from blood samples detected by mNGS in the early stage of the disease. With disease progression and after recurrent antibiotic treatment, significant dynamic changes of the microbial species from the BALF and blood samples could be clearly found by mNGS.
Conclusions. This study emphasizes the utility of mNGS in the rapid simultaneous detection of pathogens from both BALF and blood samples in patients with severe pneumonia, and could allow determination of bloodstream infection and guide clinicians regarding antimicrobial treatments.
-
-
-
-
Evaluation of ResistancePlus MG FleXible, a ‘near-patient’ test for the detection of Mycoplasma genitalium and macrolide resistance mutations, using freshly collected clinical samples
Introduction. Mycoplasma genitalium is a sexually transmitted pathogen with increasing resistance to first- and second-line antimicrobials. The ‘near-patient test’ ResistancePlus MG FleXible (SpeeDx) detects M. genitalium plus four macrolide resistance mutations (MRMs), facilitating same-day patient follow up.
Hypothesis/Gap Statement. This assay has not been assessed on freshly collected samples.
Aim. Our goal was to evaluate the performance of the ResistancePlus MG FleXible test against the standard of care open platform test.
Methods. ResistancePlus MG FleXible (analysed on the Cepheid GeneXpert platform) was evaluated on freshly collected samples and compared to the standard of care open platform test ResistancePlus MG (SpeeDx) analysed on the LightCycler 480 II (Roche).
Results. For 270 valid tests, ResistancePlus MG FleXible yielded a high positive per cent agreement (PPA) of 94.1% [96/102; 95 % confidence interval (CI): 87.6–97.8 %] and negative per cent agreement (NPA) of 95.2% (160/168; 95 % CI: 90.8–97.9%) for M. genitalium detection compared to the reference assay (kappa for test concordance of 0.89; 95 % CI: 0.83–0.95). Performance was similar across different sample types. For the detection of MRMs, ResistancePlus MG FleXible had a PPA of 97.1% (66/68; 95% CI: 89.8–99.6) and NPA of 78.6% (22/28; 95 % CI: 59.0–91.7), with test comparison kappa of 0.79 (95 % CI: 0.65–0.93). Notably, of six discordant results (i.e. determined to be wild type by the reference assay), five were positive for MRMs by Sanger sequencing, indicating that the ResistancePlus MG FleXible assay has an improved performance for mutation detection.
Conclusion. ResistancePlus MG FleXible had comparable test performance for M. genitalium detection as the open platform assay, with improved detection of MRMs. The ResistancePlus MG FleXible ‘near-patient’ assay can deliver a rapid result to expedite appropriate treatment.
-
- Medical Mycology
-
-
-
IgG reactivity profile to Paracoccidioides spp. antigens in people with asymptomatic Paracoccidioidomycosis
Introduction. Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides spp. As the disease is known to affect mostly men over 40 years old who previously worked handling soil, some cities of agricultural economy in endemic regions may have more cases of paracoccidioidal infection.
Gap statement. The true frequency of PCM cannot be established in Brazil because it is not a disease of mandatory reporting. The detection of paracoccidioidal infection may assist in the planning of health services, in order to provide early detection of the disease and to prevent its worsening or even progression to death. In addition, little is described about sera reactivity with antigens from different species of Paracoccidiodes, especially P. lutzii.
Aim. Current research was conducted in an inland municipality of southern Brazil, in order to assess infection rate within this endemic region of PCM disease.
Methodology. ELISA was employed to evaluate 359 sera from random volunteers from Guarapuava, Paraná, Brazil, to detect IgG against cell-free antigens (CFA) from P. restrepiensis B339, P. americana LDR3 and P. lutzii LDR2. Confirmatory ELISA employed gp43 from B339. Reduction of cross-reactions was sought by treatment with sodium metaperiodate (SMP-CFA, SMP-gp43). Immunoblot was performed with 37 selected sera among those reactive in ELISA. Epidemiological profile was assessed by questionnaire.
Results. ELISA reactivity was: CFA/SMP-CFA in general 37.3/17.8 %, B339 25.3/14.5 %, LDR3 24.5/1.4 %, LDR2 8.3/5.8 %; gp43/SMP-gp43 7.2/4.7 %. There were sera reactive with multiple CFAs. In immunoblot, five sera showed the same reaction profile with P. lutzii’s antigens as PCM disease sera. Rural residence and soil-related professions were risk factors for paracoccidioidal infection.
Conclusion. The low prevalence is in accordance with previous reports of lower PCM disease endemicity in Guarapuava than in other areas of Paraná. Although P. brasiliensis seems to be the prevalent strain of the region, 21 sera from people who only lived in Guarapuava reacted with P. lutzii LDR2. CFA-ELISA with whole antigens seems a good option for serological screening in epidemiological surveys.
-
-
- Molecular and Microbial Epidemiology
-
-
-
Emergence of clinical isolates of Pseudomonas asiatica and Pseudomonas monteilii from Japan harbouring an acquired gene encoding a carbapenemase VIM-2
Pseudomonas asiatica and Pseudomonas monteilii , belonging to the Pseudomonas putida phylogenetic group, are occasionally isolated from clinical samples, partly because they are often misidentified as P. putida in clinical laboratories. There are five reports describing carbapenem-resistant clinical isolates of these species. Carbapenem-resistant strains of P. asiatica and P. monteilii were isolated from stool samples. These isolates were sequenced using Illumina MiSeq and reidentified using average nucleotide identity (ANI) based on comparisons of their whole-genome sequences using the OrthoANI algorithm. The clonal relatedness of the isolates was assessed by pulse-field gel electrophoresis (PFGE). The size of plasmids conveying bla VIM-2 was examined by Southern blotting. A total of six carbapenem-resistant clinical isolates of P. asiatica (two isolates) and P. monteilii (four isolates) were obtained from stool samples from five patients in a Japanese hospital. All isolates harboured blaVIM-2 . The two isolates of P. asiatica had a different pattern in the PFGE analysis, with both having a 23 kb plasmid. Of the four isolates of P. monteilii with similar patterns in the PFGE analysis, three had 320 kb plasmids and one had a 240 kb plasmid. The genetic environments of the 320/240 kb and 23 kb plasmids differed. The results strongly indicated that carbapenem-resistant P. asiatica and P. monteilii producing metallo-β-lactamase are emerging in Japan. This is the first report of carbapenem-resistant P. asiatica and P. monteilii in Japan.
-
-
-
-
Seroprevalence of hepatitis B, hepatitis C and HIV infection among patients undergoing haemodialysis in Buenos Aires, Argentina
Introduction. Blood-borne infections are a major cause of harm in individuals on haemodialysis (HD). In particular, knowledge about hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV) status in HD patients is a major concern, since these infections may cause comorbidities in this setting. There is a paucity of data regarding this issue in Argentina.
Hypothesis/Gap Statement. The epidemiological surveillance of HBV, HCV, and HIV is a fundamental tool for planning and implementing health strategies in order to prevent and control viral transmission of these viral agents.
Aim. To determine the seroprevalence of HBV, HCV and HIV infections in HD patients in Buenos Aires, Argentina.
Methodology. Seven hundred and forty-eight HD patients were included in a retrospective cross-sectional study. Serological assays were performed to determine HBV, HCV and HIV status. HBV HBsAg and anti-HBc IgG were analysed using AxSYM (samples before 2010) or the Architect Abbott system (samples since 2010), anti-HCV IgG testing was performed using the anti-HCV enzyme immunoassay AxSYM HCV V3.0 and ARCHITECT anti-HCV, while HIV was tested for using AxSYM HIV 1/2 gO and ARCHITECT HIV Ag/Ab Combination. HCV genotyping was carried out by phylogenetic analysis of the NS5B partial gene.
Results. Infection with one of the viruses was detected in 31.1 % of patients [HBV in 82 (11.0 %), HCV in 179 (23.9 %) and HIV in 6 (0.8 %)]. Thirty-two (4.3 %) patients had 2 virus markers [27 (3.6 %) with HCV/HBV, 4 (0.5 %) with HCV/HIV and 1 (0.13 %) with HBV/HIV]. Finally, a single patient (0.13 %) presented all three markers. Time on dialysis was correlated with HCV but not with HBV infection. The HCV subtype distribution in HD patients was inverted with respect to that observed in the general population (HCV-1a 73.2 % and HCV-1b 26.8 % in HD vs HCV-1a 26.5 % and HCV-1b 73.5 % in the general population, P <0.001).
Conclusion. Despite the implementation of universal precautionary biosafety standards for dialysis, infection with HBV and HCV continues to occur at very high rates in HD patients. The results emphasize the need to carry out proactive tasks for early diagnosis and treatment of infected individuals and to vaccinate those with non-protective antiHBs antibodies in order to reduce morbidity and mortality in HD patients.
-
- Pathogenesis, Virulence and Host Response
-
-
-
Modelling persistent Mycoplasma pneumoniae biofilm infections in a submerged BEAS-2B bronchial epithelial tissue culture model
More LessIntroduction. Infections with the respiratory pathogen Mycoplasma pneumoniae are often chronic, recurrent and resistant, persisting after antibiotic treatment. M. pneumoniae grown on glass forms protective biofilms, consistent with a role for biofilms in persistence. These biofilms consist of towers of bacteria interspersed with individual adherent cells.
Hypothesis/Gap Statement. A tissue culture model for M. pneumoniae biofilms has not been described or evaluated to address whether growth, development and resistance properties are consistent with persistence in the host. Moreover, it is unclear whether the M. pneumoniae cells in the biofilm towers and individual bacterial cells have distinct roles in disease.
Aim. We evaluated the properties of biofilms of M. pneumoniae grown on the immortalized human bronchial epithelial cell line BEAS-2B in relation to persistence in the host. We observed nucleation of biofilm towers and the disposition of individual cells in culture, leading to a model of how tower and individual cells contribute to infection and disease.
Methodology. With submerged BEAS-2B cells as a substrate, we evaluated growth and development of M. pneumoniae biofilms using scanning electron microscopy and confocal laser scanning microscopy. We characterized resistance to erythromycin and complement using minimum inhibitory concentration assays and quantification of colony forming units. We monitored biofilm tower formation using time-lapse microscopic analysis of host-cell-free M. pneumoniae cultures.
Results. Bacteria grown on host cells underwent similar development to those grown without host cells, including tower formation, rounding and incidence of individual cells outside towers. Erythromycin and complement significantly reduced growth of M. pneumoniae . Towers formed exclusively from pre-existing aggregates of bacteria. We discuss a model of the M. pneumoniae biofilm life cycle in which protective towers derive from pre-existing aggregates, and generate individual cytotoxic cells.
Conclusion . M. pneumoniae can form protective biofilms in a tissue culture model, implicating biofilms in chronic infections, with aggregates of M. pneumoniae cells being important for establishing infections.
-
-
-
-
Stenotrophomonas maltophilia phenotypic and genotypic features through 4-year cystic fibrosis lung colonization
Introduction. Stenotrophomonas maltophilia has emerged as one of the most common multi-drug-resistant pathogens isolated from people with cystic fibrosis (CF). However, its adaptation over time to CF lungs has not been fully established.
Hypothesis. Sequential isolates of S. maltophilia from a Brazilian adult patient are clonally related and show a pattern of adaptation by loss of virulence factors.
Aim. To investigate antimicrobial susceptibility, clonal relatedness, mutation frequency, quorum sensing (QS) and selected virulence factors in sequential S. maltophilia isolates from a Brazilian adult patient attending a CF referral centre in Buenos Aires, Argentina, between May 2014 and May 2018.
Methodology. The antibiotic resistance of 11 S. maltophilia isolates recovered from expectorations of an adult female with CF was determined. Clonal relatedness, mutation frequency, QS variants (RpfC–RpfF), QS autoinducer (DSF) and virulence factors were investigated in eight viable isolates.
Results. Seven S. maltophilia isolates were resistant to trimethoprim–sulfamethoxazole and five to levofloxacin. All isolates were susceptible to minocycline. Strong, weak and normomutators were detected, with a tendency to decreased mutation rate over time. XbaI PFGE revealed that seven isolates belong to two related clones. All isolates were RpfC–RpfF1 variants and DSF producers. Only two isolates produced weak biofilms, but none displayed swimming or twitching motility. Four isolates showed proteolytic activity and amplified stmPr1 and stmPr2 genes. Only the first three isolates were siderophore producers. Four isolates showed high resistance to oxidative stress, while the last four showed moderate resistance.
Conclusion. The present study shows the long-time persistence of two related S. maltophilia clones in an adult female with CF. During the adaptation of the prevalent clones to the CF lungs over time, we identified a gradual loss of virulence factors that could be associated with the high amounts of DSF produced by the evolved isolates. Further, a decreased mutation rate was observed in the late isolates. The role of all these adaptations over time remains to be elucidated from a clinical perspective, probably focusing on the damage they can cause to CF lungs.
-
Volumes and issues
-
Volume 73 (2024)
-
Volume 72 (2023 - 2024)
-
Volume 71 (2022)
-
Volume 70 (2021)
-
Volume 69 (2020)
-
Volume 68 (2019)
-
Volume 67 (2018)
-
Volume 66 (2017)
-
Volume 65 (2016)
-
Volume 64 (2015)
-
Volume 63 (2014)
-
Volume 62 (2013)
-
Volume 61 (2012)
-
Volume 60 (2011)
-
Volume 59 (2010)
-
Volume 58 (2009)
-
Volume 57 (2008)
-
Volume 56 (2007)
-
Volume 55 (2006)
-
Volume 54 (2005)
-
Volume 53 (2004)
-
Volume 52 (2003)
-
Volume 51 (2002)
-
Volume 50 (2001)
-
Volume 49 (2000)
-
Volume 48 (1999)
-
Volume 47 (1998)
-
Volume 46 (1997)
-
Volume 45 (1996)
-
Volume 44 (1996)
-
Volume 43 (1995)
-
Volume 42 (1995)
-
Volume 41 (1994)
-
Volume 40 (1994)
-
Volume 39 (1993)
-
Volume 38 (1993)
-
Volume 37 (1992)
-
Volume 36 (1992)
-
Volume 35 (1991)
-
Volume 34 (1991)
-
Volume 33 (1990)
-
Volume 32 (1990)
-
Volume 31 (1990)
-
Volume 30 (1989)
-
Volume 29 (1989)
-
Volume 28 (1989)
-
Volume 27 (1988)
-
Volume 26 (1988)
-
Volume 25 (1988)
-
Volume 24 (1987)
-
Volume 23 (1987)
-
Volume 22 (1986)
-
Volume 21 (1986)
-
Volume 20 (1985)
-
Volume 19 (1985)
-
Volume 18 (1984)
-
Volume 17 (1984)
-
Volume 16 (1983)
-
Volume 15 (1982)
-
Volume 14 (1981)
-
Volume 13 (1980)
-
Volume 12 (1979)
-
Volume 11 (1978)
-
Volume 10 (1977)
-
Volume 9 (1976)
-
Volume 8 (1975)
-
Volume 7 (1974)
-
Volume 6 (1973)
-
Volume 5 (1972)
-
Volume 4 (1971)
-
Volume 3 (1970)
-
Volume 2 (1969)
-
Volume 1 (1968)