Background Legionnaires' disease is under-diagnosed because of inconsistent use of diagnostic tests and uncertainty about whom to test. We assessed the increase in case detection following large-scale introduction of routine PCR testing of respiratory specimens in New Zealand. Methods LegiNZ was a national surveillance study done over 1-year in which active case-finding was used to maximise the identification of cases of Legionnaires' disease in hospitals. Respiratory specimens from patients of any age with pneumonia, who could provide an eligible lower respiratory specimen, admitted to one of 20 participating hospitals, covering a catchment area of 96% of New Zealand's population, were routinely tested for legionella by PCR. Additional cases of Legionnaires' disease in hospital were identified through mandatory notification. Findings Between May 21, 2015, and May 20, 2016, 5622 eligible specimens from 4862 patients were tested by PCR. From these, 197 cases of Legionnaires' disease were detected. An additional 41 cases were identified from notification data, giving 238 cases requiring hospitalisation. The overall incidence of Legionnaires' disease cases in hospital in the study area was 5.4 per 100 000 people per year, and Legionella longbeachae was the predominant cause, found in 150 (63%) of 238 cases. Interpretation The rate of notified disease during the study period was three-times the average over the preceding 3 years. Active case-finding through systematic PCR testing better clarified the regional epidemiology of Legionnaires' disease and uncovered an otherwise hidden burden of disease. These data inform local Legionnaires' disease testing strategies, allow targeted antibiotic therapy, and help identify outbreaks and effective prevention strategies. The same approach might have similar benefits if applied elsewhere in the world.

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Aim: This study aimed to describe the burden of disease and estimated rates of oropharyngeal carriage of Kingella kingae among New Zealand children. We compared polymerase chain reaction (PCR) and culture for the detection of this microorganism with a view to further development and implementation of K. kingae PCR in Christchurch Hospital.Methods: Oropharyngeal swabs from children between 6 and 48 months of age were analysed by culture to estimate carriage rates of K. kingae. Samples of a subgroup of children between 12 and 24 months of age were also tested by PCR. In addition, a retrospective review was performed on all cases of invasive K. kingae disease and children with osteoarticular infections.Results: Oropharyngeal cultures were positive for K. kingae in specimens from 4 out of 176 children (2.3%). PCR was significantly more sensitive and by PCR, the carriage rate rose to 22.9% (95% CI = 9.4-33.9%) (n = 48). From 2005 to 2015, 17 children between 6 and 48 months of age were identified with invasive infections due to K. kingae. Seventy-four children were found to have an osteoarticular infection. Most of these were culture-negative with a microbiological diagnosis made in only 15 cases (20.3%), only one due to K. kingae.Conclusions: We found a very high carriage rate of K. kingae in New Zealand children and poor performance of K. kingae culture. It is likely that many cases of invasive K. kingae infections remain undetected. We recommend the use of a K. kingae PCR in all children under 4 years of age with a possible osteoarticular infection.

TO THE EDITOR—We commend Murdoch et al for the interesting report on the utility of routine systematic use of polymerase chain reaction (PCR) testing in Legionnaires’ disease [1]. Routine PCR testing of respiratory specimens of all patients with pneumonia, or immunocompromised patients or those who had a Legionella urinary antigen ordered, yielded 114 cases over 4 years of predominantly Legionella longbeachae (a 4-fold increase after application of routine testing). This strategy detected less-severe disease and resulted in reduced length of stay [1]. The current Infectious Diseases Society of America/American Thoracic Society guidelines recommend testing all patients with severe community-acquired pneumonia (CAP) with both the Legionella and pneumococcal urinary antigen tests [2]. Regional Legionella epidemiology should be considered when generalizing the authors’ approach. Recent data highlight a low incidence of Legionella in Texas, with just 4 cases reported in 2009–2010 compared with 170 cases nationwide [3]. Prior report indicated a 6fold higher incidence of Legionella in the mid-Atlantic area compared with the South-Central area in the United States [4]. We reported a very low rate of 0.19% of Legionella in our central Texas cohort of 5543 hospitalized pneumonia patients over a decade using the BinaxNOW Legionella urinary antigen test (Binax Inc, Scarborough, Maine), despite a considerable increase in the number of tests ordered over that period [5]. Although 6 of our 11 patients with Legionella pneumonia were admitted to the intensive care unit, all had received appropriate initial empiric therapy. Our data did not strongly support routine urinary antigen testing for all hospitalized pneumonia in our region. The total cost of using the urinary antigen test as a diagnostic screening test in our study was estimated to be $158 936.48 vs an expected cost of $488 928.90 using a Legionella species molecular PCR (LEGRP, Mayo Medical Laboratories). The US Centers for Disease Control and Prevention does not recommend PCR testing for Legionella due to its variability in different laboratories (available at: http://www.cdc.gov/legionella/diagnostictesting.html). Conceivably, PCR testing could enhance detection of Legionella, but we speculate these infections would be less severe and would be covered by empiric macrolide-based antimicrobial regimens. Systematic PCR testing can be fiscally meaningful in patients with severe CAP, in a suspected outbreak, or in suspected hospital-acquired Legionnaires’ disease.

To the Editor: Legionnaires’ disease, particularly that caused by non-pneumophila species, is notoriously underdiagnosed [1, 2]. We recently found a four-fold increase in case detection of Legionnaires’ disease through a laboratory-initiated strategy of systematic PCR testing for Legionella species of all lower respiratory specimens from patients with pneumonia or immune compromised status [3]. This strategy relies on the availability of lower respiratory specimens and the recording of relevant clinical information on laboratory requisition forms by clinicians. We recognised that this strategy will miss testing patients who could not expectorate sputum and when inadequate clinical information is written on laboratory requisition forms. To address this diagnostic gap we enhanced case detection by actively identifying patients with community-acquired pneumonia (CAP) and by collecting induced sputum from those unable to expectorate voluntarily. In addition, we evaluated throat swabs as an alternative specimen for PCR testing. From October 2012 to March 2013 patients admitted to Christchurch Hospital and The Princess Margaret Hospital (both in Christchurch, New Zealand) with CAP and aged ≥18 years were recruited. For logistical reasons, recruitment occurred on weekdays only. The study period was chosen to coincide with peak Legionnaires’ disease activity in Christchurch [3]. Patients were excluded if the pneumonia was hospital acquired or associated with bronchial obstruction, bronchiectasis or tuberculosis. Patients were not eligible for sputum induction if they required high-flow oxygen or assisted ventilation at enrolment. Ethical approval was obtained from the New Zealand Northern A Ethics Committee. Informed consent was obtained from the patient or their next of kin with …

TO THE EDITOR—We agree with Dr Boethel and colleagues that regional epidemiology must be considered for any diagnostic testing strategy for Legionnaires’ disease [1]. We emphasize this in our article, and suggest that a period of systematic polymerase chain reaction (PCR) testing can better characterize the regional epidemiology of Legionnaires’ disease and inform local testing strategies [2]. Thereafter, ongoing systematic PCR testing may not be suitable for all regions of the world, but may be warranted during seasonal peak periods of activity. Importantly, regional epidemiology will not be properly assessed if the only diagnostic tools used are the urinary antigen test and the occasional use of culture. The survey in the abstract referred to by Boethel and colleagues [3] has only provided data on Legionella pneumophila serogroup 1, as this is the only species and serogroup detected by the urinary antigen test. There is no information on other L. pneumophila serogroups or other Legionella species. This diagnostic bias is widespread in many countries that rely on diagnostic tests that favor or detect only L. pneumophila serogroup 1, and is partially responsible for the lack of attention to non–L. pneumophila species and sporadic disease. In our study, we would have missed 86% of cases of Legionnaires’ disease had we used the urinary antigen test as our sole diagnostic method [2]. With the combination of good diagnostic accuracy, the ability to detect all Legionella species, and rapid turnaround time, PCR can be regarded as the diagnostic test of choice for Legionnaires’ disease. Cost and technical expertise are also not the barriers they previously were. Boethel and colleagues have misquoted their Centers for Disease Control and Prevention source (available at: http://www.cdc.gov/ legionella/diagnostic-testing.html); the variability of assays between laboratories is listed as a disadvantage, but there is no recommendation against the use of PCR. As we have shown, with our PCR testing strategy we detected a greater proportion of Legionnaires’ disease patients with less-severe disease [2]. However, 29% still required intensive care unit admission and 9% died in hospital, and PCR was the only positive diagnostic test for more than one-third of these patients. Therefore, we disagree with the implication that PCR will mainly detect less-severe disease. Concern about Legionnaires’ disease is a major driver for the widespread reliance on broad-spectrum empiric antibiotic treatment for community-acquired pneumonia [4]. Use of Legionella PCR provides the opportunity for more rational use of antibiotics, especially in regions with a relatively high incidence of Legionnaires’ disease. The old adage “look and you will find it” is particularly pertinent to Legionnaires’ disease diagnostics. Similarly, you can only truly understand the regional epidemiology of Legionnaires’ disease by using a comprehensive testing strategy that detects all Legionella species and serogroups.

BACKGROUND Legionnaires' disease cannot be clinically or radiographically distinguished from other causes of pneumonia, and specific tests are required to make the diagnosis. Currently, testing occurs erratically and, instead, clinicians rely on empiric treatment strategies and ignore public health implications of the diagnosis. We aimed to measure the increase in case detection of Legionnaires' disease following the introduction of routine polymerase chain reaction (PCR) testing of respiratory specimens. PCR is the most sensitive diagnostic tool for Legionnaires' disease. METHODS In a quasi-experimental study in Christchurch, New Zealand, we compared the number of cases of Legionnaires' disease requiring hospitalization diagnosed during a 2-year period before the introduction of a routine PCR testing strategy (November 2008-October 2010) with a similar period after the introduction (November 2010-October 2012). With this testing strategy, all respiratory specimens from hospitalized patients with pneumonia sent to the region's sole tertiary-level laboratory were tested for Legionella by PCR, whether requested or not. RESULTS During November 2008 to October 2010, there were 22 cases of Legionnaires' disease compared with 92 during November 2010 to October 2012. Of 1834 samples tested since November 2010, 1 in 20 was positive, increasing to 1 in 9 during peak Legionella season (November to January). Increasing bacterial load was associated with increasing disease severity. CONCLUSIONS In our region, the burden of Legionnaires' disease is much greater than was previously recognized. Routine PCR testing provides results within a clinically relevant time frame and enables improved characterization of the regional epidemiology of Legionnaires' disease.

Ochroconis gallopava has rarely been isolated in immunosuppressed patients. We report the first case to our knowledge of O. gallopava peritonitis in a cardiac transplant patient on continuous ambulatory peritoneal dialysis. A 58-year-old man who had undergone cardiac transplant 8 years earlier alerted his dialysis nurses to the presence of black material in his catheter lumen. Fungal hyphae were seen on direct microscopy of the black material and from the dialysate effluent, and O. gallopava was cultured from both after 1 day. He was treated successfully with a single dose of intravenous voriconazole, followed by 2 weeks of oral voriconazole.

Streptococcus pseudopneumoniae is a recently described streptococcus that is phenotypically and genetically distinct from Streptococcus pneumoniae and other viridans streptococci. Key characteristics of S. pseudopneumoniae are the absence of a pneumococcal capsule, insolubility in bile, resistance or indeterminate susceptibility to optochin when incubated in 5% CO2 but susceptibility to optochin when incubated in ambient air, and a positive reaction with the AccuProbe DNA probe hybridization test. The clinical importance of this bacterium is currently unknown. We report the characteristics and associated clinical data of 35 strains of S. pseudopneumoniae isolated from sputum samples from 33 patients. All isolates produced a positive result with the NOW S. pneumoniae antigen test (Binax, Inc.). No isolate was resistant to penicillin, but 60% were resistant to erythromycin and 77% were resistant to tetracycline. All patients had lower respiratory tract symptoms, 79% had chronic obstructive pulmonary disease (COPD), and 33% had chest radiographic infiltrates. Compared with matched control patients who had Streptococcus pneumoniae isolated from sputum, patients with S. pseudopneumoniae infection were more likely to have a history of COPD (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.67 to 20.11) or exacerbation of COPD (OR, 6.5; 95% CI, 2.61 to 16.20). Further research is needed to better characterize the epidemiology of S. pseudopneumoniae colonization and the role of S. pseudopneumoniae in COPD and other diseases.