CITROBACTER ENDOGENOUS ENDOPHTHALMITIS: A CASE REPORT AND REVIEW OF THE LITERATURE.

PURPOSE: We present a case of endogenous endophthalmitis because of an unusual bacterium, Citrobacter koseri. PATIENT: A 57-year-old woman without previous history of eye surgery or trauma presented with diabetic ketoacidosis and a painful right eye with the reduction of vision. C. koseri was identified in blood culture; thus, a diagnosis of right eye endogenous endophthalmitis was made. Intravenous and intravitreal antibiotics were both started, and vitreous culture further confirmed C. koseri as the causative organism. Computed tomography of the abdomen and pelvis revealed a right C-shaped perinephric abscess, which was drained under ultrasound guidance. RESULTS: Because of rapid progression to corneal melting, evisceration was performed. CONCLUSION: Cases of endogenous endophthalmitis caused by Citrobacter are very limited, and a review of all published cases in the English literature and the present case revealed that endogenous Citrobacter endophthalmitis arose almost entirely from Citrobacter renal infection. Early recognition and drainage of renal abscess may lower the chance of uncontrolled infection and endogenous spread to the eyes. Despite prompt and intensive treatment, the clinical outcome of Citrobacter endogenous endophthalmitis seems to be poor.

Occurrence of Highly Conjugative IncX3 Epidemic Plasmid Carrying bla NDM in Enterobacteriaceae Isolates in Geographically Widespread Areas.

The emergence of New Delhi metallo-ß-lactamase (NDM) in common enterobacterial species is a major concern for healthcare. Early reports have revealed that the spread of NDM involved diverse and heterogeneous plasmids. Recently, the involvement of a rare, IncX3 subtype plasmid has been increasingly recognized. Here, we studied the prevalence of IncX plasmid subtypes in 198 carbapenem-resistant Enterobacteriaceae, originating from a territory-wide active surveillance in Hong Kong in 2016. The complete sequences and biological features of the bla NDM-carrying plasmids were investigated. A total of 62 NDM-type, 21 OXA-48 type, 14 IMP-type, 8 KPC-type, 4 IMI-type producers, and 89 non-carbapenemase-producers were tested for presence of IncX subtypes. IncX3 (n = 60) was the most common subtype, followed by IncX4 (n = 6) and IncX1 (n = 2). The prevalence of IncX3 subtype in isolates producing NDM, other carbapenemase types and non-carbapenemase producers were 75.8, 21.3, and 3.4%, respectively (P < 0.001). An IncX3 plasmid (size ∼50 kb) was confirmed to carry bla NDM in 47 isolates of different enterobacterial species. Thirteen IncX3 plasmids originating from six healthcare regions in Hong Kong were completely sequenced. The results showed that the IncX3 plasmids carrying bla NDM share a high degree of sequence identity with a previously reported plasmid, pNDM-HN380 (GenBank accession JX104760), over the backbone and genetic load regions. A blast search further revealed the occurrence of identical or nearly identical IncX3 plasmids carrying bla NDM in other part of China, Korea, Myanmar, India, Oman, Kuwait, Italy, and Canada. Two IncX3 carrying bla NDM were investigated further. Conjugation experiments demonstrated that the IncX3 plasmids could be efficiently transferred to multiple enterobacterial species at frequencies that are comparable or higher than the epidemic IncFII plasmid carrying bla CTX-M (pHK01). In addition, efficient transfer of the NDM plasmids occurred over a range of temperatures. In conclusion, this study demonstrated the important role played by IncX3 in the dissemination of NDM and the occurrence of pNDM-HN380-like plasmids in geographically widespread areas. The high mobility of IncX3 plasmid across different enterobacterial species highlights the ability of this plasmid replicon to be an important vehicle in worldwide dissemination of NDM.

Rapid Detection of Carbapenemase Production in Enterobacteriaceae by Use of a Modified Paper Strip Carba NP Method.

Rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is important for preventing their spread in health care settings. We compared the performance of the Carba NP (CNP) test using the CLSI tube method with that using a modified paper strip method for the detection of carbapenemases in 390 Enterobacteriaceae isolates. The isolates were identified by Hong Kong's carbapenem-resistant Enterobacteriaceae surveillance program in 2016 and comprised 213 CPE and 177 carbapenemase-negative Enterobacteriaceae isolates. Molecular genotype was used as the reference. The test results were read at different time points for the CLSI method (1 min, 5 min, 1 h, and 2 h) and strip method (1 min and 5 min). The strip CNP and CLSI CNP tests correctly detect carbapenemase production in 93% and 93% of KPC producers, 100% and 38% of IMI producers, 94% and 85% of IMP producers, 98% and 90% of NDM producers, and 29% and 12% of OXA producers, respectively. Overall, the strip method has superior sensitivity to the CLSI method (86% versus 75%, respectively; P < 0.001, McNemar test). The specificity of both methods was 100%. By the CLSI method, 27%, 14%, 29%, and 6% of the CPE isolates were positive at 1 min, 5 min, 1 h, and 2 h, respectively. In contrast, by the strip method, 76% of the CPE isolates were positive at 1 min, and an additional 10% were positive at 5 min. In conclusion, the Carba NP test by use of the modified strip method has a higher sensitivity and a shorter assay time than that those by use of the CLSI tube method.

Corynebacterium kroppenstedtii Is an Emerging Cause of Mastitis Especially in Patients With Psychiatric Illness on Antipsychotic Medication.

This retrospective study of patients with Corynebacterium kroppenstedtii infections revealed a predominance of mastitis and a potential association with psychiatric illnesses. At least one third of our patients with C kroppenstedtii mastitis had psychiatric illness, and >92% received antipsychotic medications. Drug-induced hyperprolactinemia may be an important modifiable risk factor in these patients.

IncN ST7 epidemic plasmid carrying blaIMP-4 in Enterobacteriaceae isolates with epidemiological links to multiple geographical areas in China.

OBJECTIVES: To characterize blaIMP-4-carrying plasmids originating from inpatients in Hong Kong. METHODS: Sixteen blaIMP-4-carrying plasmids identified among Enterobacteriaceae (nine Escherichia coli, four Klebsiella pneumoniae, two Citrobacter freundii and one Enterobacter cloacae) recovered from 15 patients were characterized. The isolates, collected during January 2010 to December 2013, were retrospectively investigated by plasmid sequencing, molecular and fitness studies. RESULTS: The blaIMP-4-carrying plasmids belonged to the IncN ST7 lineage (∼50 kb). Twelve of the 16 plasmids were epidemiologically linked to seven different regions in China. Alignment of the complete plasmid sequences showed identical plasmid backbones and two highly similar resistance regions, each carrying one of two resistance genes (blaIMP-4 and qnrS1). The blaIMP-4 was detected in a class 1 integron (containing blaIMP-4 and intron Kl.pn.13) that is part of an IS6100-IS26 transposon-like structure. The nine E. coli carrying the epidemic plasmid belonged to multiple multilocus STs (six ST542, one ST131, one ST657 and one ST3177). Fitness assays performed on E. coli J53 recipients showed that the presence of the epidemic plasmid did not have a significant biological cost. CONCLUSIONS: This study identified a blaIMP-4-carrying IncN ST7 plasmid disseminated among multiple enterobacterial species originating from patients with epidemiological links to different regions in China.

Comparison of acute hepatitis E infection outcome in patients with and without chronic hepatitis B infection: a 10 year retrospective study in three regional hospitals in Hong Kong.

BACKGROUND: Acute hepatitis E virus (HEV) infection has recently become the commonest cause of acute viral hepatitis in Hong Kong (HK) with majority of HEV belonging to genotype 4. Studies from China have shown that acute hepatitis E patients with underlying chronic hepatitis B virus (HBV) infection may have a worse outcome than those without. In India where genotype 1 is more prevalent, superinfection with hepatitis E on patients with chronic liver disease including chronic hepatitis B infection can cause liver decompensation. OBJECTIVES: The study aims to determine the clinical outcome of acute hepatitis E infection in patients with and without chronic hepatitis B infection in HK. STUDY DESIGN: The rates of liver failure, liver-related mortality and all-cause mortality will be compared between acute hepatitis E patients with and without chronic hepatitis B. Analysis was performed using the Statistical Package for the Social Science (SPSS version 12.0). All statistical tests were two-sided, and statistical significance was taken as p<0.05. RESULTS: Chronic HBV carriers with acute HEV infection were found to have higher liver failure rate, liver-related mortality and all-cause mortality, but the results did not reach statistical significance. Chronic HBV carriers were found to have statistically significantly lower admission ALT level, lower day 28 serum albumin level and higher day 28 serum ALT level. CONCLUSIONS: A prospective study with sufficient sample size is needed to confirm whether the clinical outcome of patients with chronic HBV infection is worse compared with patients who were not chronic HBV carriers.

Surfactant protein B gene polymorphism is associated with severe influenza.

BACKGROUND: Surfactant proteins play a key role in alveolar stability. We examined whether single nucleotide polymorphisms (SNPs) related to the surfactant protein genes are associated with severe influenza. METHODS: In the first cohort, 12 SNPs related to surfactant protein genes were compared between Chinese patients with severe and mild pandemic 2009 influenza A(H1N1) (A[H1N1]pdm09) infection who were matched for age, sex, and underlying risk conditions. The SNP rs1130866, which was significantly different between the two groups, was further genotyped in a second cohort of patients. Multivariate analysis was performed to control for confounding factors. The genotype frequencies were also compared with those of the general Han Chinese population. RESULTS: This study consisted of 380 patients with A(H1N1)pdm09 infection. In the first cohort of 84 patients, the C allele of rs1130866, an SNP in the surfactant protein B gene (SFTPB), was significantly associated with severe disease (OR = 3.37, P = .0048), although the P value was .057 after Bonferroni correction. In the second cohort of 296 patients, the C/C genotype was confirmed in the univariate analysis to be associated with severe disease. Multivariate analysis of the second cohort showed that genotype C/C was an independent risk factor for severe A(H1N1)pdm09 infection (second cohort: OR = 2.087, P = .023). Compared to the general Han Chinese population, the C/C genotype was overrepresented in patients with severe A(H1N1)pdm09 infection (OR = 3.232, P = .00000056). CONCLUSIONS: SFTPB polymorphism is associated with severe influenza. The role of SFTPB in influenza warrants further studies.

Delayed clearance of viral load and marked cytokine activation in severe cases of pandemic H1N1 2009 influenza virus infection.

BACKGROUND: Infections caused by the pandemic H1N1 2009 influenza virus range from mild upper respiratory tract syndromes to fatal diseases. However, studies comparing virological and immunological profile of different clinical severity are lacking. METHODS: We conducted a retrospective cohort study of 74 patients with pandemic H1N1 infection, including 23 patients who either developed acute respiratory distress syndrome (ARDS) or died (ARDS-death group), 14 patients with desaturation requiring oxygen supplementation and who survived without ARDS (survived-without-ARDS group), and 37 patients with mild disease without desaturation (mild-disease group). We compared their pattern of clinical disease, viral load, and immunological profile. RESULTS: Patients with severe disease were older, more likely to be obese or having underlying diseases, and had lower respiratory tract symptoms, especially dyspnea at presentation. The ARDS-death group had a slower decline in nasopharyngeal viral loads, had higher plasma levels of proinflammatory cytokines and chemokines, and were more likely to have bacterial coinfections (30.4%), myocarditis (21.7%), or viremia (13.0%) than patients in the survived-without-ARDS or the mild-disease groups. Reactive hemophagocytosis, thrombotic phenomena, lymphoid atrophy, diffuse alveolar damage, and multiorgan dysfunction similar to fatal avian influenza A H5N1 infection were found at postmortem examinations. CONCLUSIONS: The slower control of viral load and immunodysregulation in severe cases mandate the search for more effective antiviral and immunomodulatory regimens to stop the excessive cytokine activation resulting in ARDS and death.

Diagnostic challenges of tuberculosis peritonitis in patients with and without end-stage renal failure.

BACKGROUND: Information about diagnostic features of tuberculosis (TB) peritonitis among patients with end-stage renal failure (ESRF), compared with those without ESRF, is limited. Here, we review our experience with TB peritonitis in patients with and without ESRF over a period of 11 years, with special reference to the clinical features of and diagnostic tools for TB peritonitis. METHODS: The records of all patients with TB peritonitis who were seen at United Christian Hospital (Hong Kong) from 1996 through 2006 were reviewed. The diagnosis of TB peritonitis was based on (1) detection of mycobacteria on smear and/or Mycobacterium tuberculosis on culture of ascitic fluid and/or peritoneal biopsy specimens and/or (2) demonstration of caseating granulomata on histological assessment of peritoneal biopsy specimens. RESULTS: During the study period, 52 patients (19 without ESRF and 33 with ESRF) had TB peritonitis. Patients with ESRF tended to have more-acute onset of symptoms and neutrophil-predominant peritoneal fluid, which mimicked bacterial peritonitis. Diagnosis was made earlier among patients without ESRF than among those with ESRF. Laparotomy or laparoscopy was the initial diagnostic tool for 12 patients (63%) without ESRF, whereas mycobacterial culture was the diagnostic method for 18 patients (55%) with ESRF. CONCLUSIONS: TB peritonitis has nonspecific and protean manifestations. It should be considered in the context of culture-negative peritonitis and in the context of culture-positive peritonitis that fails to respond to appropriate antibiotics. Laparoscopy with biopsy should be considered at an early stage when TB peritonitis is suspected.

[Severe acute respiratory syndrome (SARS)]. / Schweres akutes respiratorisches Syndrom (SARS).

The sudden appearance of the severe acute respiratory syndrome (SARS) in 2003 demonstrated to the world at large that despite the high standard of medical care in affected countries, a highly contagious emerging infectious disease could spread rapidly worldwide. By application and improvement of stringent infection control measures, a further spread of SARS could be stopped and the disease could so far be defeated. In the meantime, decisive progress in the knowledge about the structure and further characteristics of the SARS coronavirus (SARS-CoV) have been made, including the likely virus reservoir and the ways of spread. Validated diagnostic tests are now available and are further being improved. Effective vaccines and antiviral agents are being developed. Of imminent importance to prepare against a resurgence of SARS, remain, besides an exact knowledge about the viral pathogen and its possible further behavior, constant vigilance, early recognition, and instant isolation of suspected cases of SARS.

Clinical isolates of Streptococcus iniae from Asia are more mucoid and beta-hemolytic than those from North America.

Streptococcus iniae, a widely distributed fish pathogen, is known to cause rare cases of human infection. We describe 2 cases of invasive S. iniae infection, one with septic arthritis complicating chronic gout and the other with bacteremic cellulitis. Both patients were Chinese and have been regularly handling fresh fish for cooking. Both isolates were unidentified or misidentified by 3 commercially available identification system and were only identified by 16S rRNA gene sequencing. When compared with a clinical isolate of S. iniae from Canada, their colonies were larger, more beta-hemolytic, and microcoid. Although bacteremic cellulitis has been described as the most common infection associated with S. iniae, the bacterium has not been reported to cause exacerbations of gouty arthritis previously. Clinical laboratories should be aware of the possibility of different colony morphology of S. iniae from Asia. More accurate identification of nongroupable beta-hemolytic streptococci, especially from patients with epidemiologic linkage to fresh fish, may uncover more cases of S. iniae infection. The Asian population and handlers of fresh fish should be informed of the risk of acquiring S. iniae infection.

Clinical and molecular epidemiological features of coronavirus HKU1-associated community-acquired pneumonia.

BACKGROUND: Recently, we described the discovery of a novel group 2 coronavirus, coronavirus HKU1 (CoV-HKU1), from a patient with pneumonia. However, the clinical and molecular epidemiological features of CoV-HKU1-associated pneumonia are unknown. METHODS: Prospectively collected (during a 12-month period) nasopharyngeal aspirates (NPAs) from patients with community-acquired pneumonia from 4 hospitals were subjected to reverse-transcription polymerase chain reaction, for detection of CoV-HKU1. The epidemiological, clinical, and laboratory characteristics of patients with CoV-HKU1-associated pneumonia were analyzed. The pol, spike (S), and nucleocapsid (N) genes were also sequenced. RESULTS: NPAs from 10 (2.4%) of 418 patients with community-acquired pneumonia were found to be positive for CoV-HKU1. All 10 cases occurred in spring and winter. Nine of these patients were adults, and 4 had underlying diseases of the respiratory tract. In the 6 patients from whom serum samples were available, all had a 4-fold change in immunoglobulin (Ig) G titer and/or presence of IgM against CoV-HKU1. The 2 patients who died had significantly lower hemoglobin levels, monocyte counts, albumin levels, and oxygen saturation levels on admission and had more-extensive involvement visible on chest radiographs. Sequence analysis of the pol, S, and N genes revealed 2 genotypes of CoV-HKU1. CONCLUSIONS: CoV-HKU1 accounts for 2.4% of community-acquired pneumonia, with 2 genotypes in the study population. Without performance of diagnostic tests, the illness was clinically indistinguishable from other community-acquired pneumonia illnesses.

Characterization and complete genome sequence of a novel coronavirus, coronavirus HKU1, from patients with pneumonia.

Despite extensive laboratory investigations in patients with respiratory tract infections, no microbiological cause can be identified in a significant proportion of patients. In the past 3 years, several novel respiratory viruses, including human metapneumovirus, severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), and human coronavirus NL63, were discovered. Here we report the discovery of another novel coronavirus, coronavirus HKU1 (CoV-HKU1), from a 71-year-old man with pneumonia who had just returned from Shenzhen, China. Quantitative reverse transcription-PCR showed that the amount of CoV-HKU1 RNA was 8.5 to 9.6 x 10(6) copies per ml in his nasopharyngeal aspirates (NPAs) during the first week of the illness and dropped progressively to undetectable levels in subsequent weeks. He developed increasing serum levels of specific antibodies against the recombinant nucleocapsid protein of CoV-HKU1, with immunoglobulin M (IgM) titers of 1:20, 1:40, and 1:80 and IgG titers of <1:1,000, 1:2,000, and 1:8,000 in the first, second and fourth weeks of the illness, respectively. Isolation of the virus by using various cell lines, mixed neuron-glia culture, and intracerebral inoculation of suckling mice was unsuccessful. The complete genome sequence of CoV-HKU1 is a 29,926-nucleotide, polyadenylated RNA, with G+C content of 32%, the lowest among all known coronaviruses with available genome sequence. Phylogenetic analysis reveals that CoV-HKU1 is a new group 2 coronavirus. Screening of 400 NPAs, negative for SARS-CoV, from patients with respiratory illness during the SARS period identified the presence of CoV-HKU1 RNA in an additional specimen, with a viral load of 1.13 x 10(6) copies per ml, from a 35-year-old woman with pneumonia. Our data support the existence of a novel group 2 coronavirus associated with pneumonia in humans.

Association of Laribacter hongkongensis in community-acquired gastroenteritis with travel and eating fish: a multicentre case-control study.

BACKGROUND: Laribacter hongkongensis has been recovered from several patients with gastroenteritis. However, the causative role of this organism in human gastroenteritis is still unproven, and sources of the bacterium are unknown. We undertook a multicentre case-control study to investigate the association of L hongkongensis with gastroenteritis. METHODS: Faecal samples from patients with community-acquired gastroenteritis and controls were cultured for L hongkongensis. Targeted food surveillance was done to identify potential sources of this bacterium. All isolates of this organism from patients and food items were characterised by pulsed-field gel electrophoresis and ribotyping. FINDINGS: During a 4-month period, L hongkongensis was recovered from 17 of 3788 patients with community-acquired gastroenteritis, but was absent in 1894 controls (p=0.001). Those who were culture-positive for this bacterium had a recent history of travel (ten [59%] patients vs two [6%] of 34 matched controls, p<0.0001), of fish consumption (16 [94%] vs 19 [56%], p=0.009), and of eating minced freshwater fish meat (five [29%] vs one [3%], p=0.012). We recovered 25 L hongkongensis isolates from intestinal samples of freshwater fish and two from minced freshwater fish meat. Bacteria with the same pulsed-field gel electrophoretic pattern and ribotype were recovered from one patient and a sample of minced freshwater fish meat, which was from the same retail market recently visited by the patient. We did not see this particular combination of electrophoretic pattern and ribotype in any other isolates. INTERPRETATION: L hongkongensis is associated with community-acquired gastroenteritis and traveller's diarrhoea. However, its causative role has not been shown. Freshwater fish is one source of this bacterium.

Use of cefoperazone MacConkey agar for selective isolation of Laribacter hongkongensis.

A new selective medium, cefoperazone MacConkey agar (CMA), was developed for primary isolation of Laribacter hongkongensis from stool. Its performance in quantitative recovery and in a clinical evaluation of 4,741 human diarrheal stool specimens was superior to that of charcoal cefoperazone deoxycholate agar. In addition, with CMA, Arcobacter butzleri was unexpectedly isolated from the stools of six patients.