Angelo Zaia

Prospective Study of a Real-Time PCR That Is Highly Sensitive, Specific, and Clinically Useful for Diagnosis of Meningococcal Disease in Children

ABSTRACT Due to the early administration of antibiotics, meningococcal disease is increasingly difficult to diagnose by culturing. Laboratory studies have shown PCR to be sensitive and specific, but there have been few clinical studies. The objectives of this study were to determine the diagnostic accuracy and clinical usefulness of meningococcal PCR through a prospective comparison of real-time PCR, nested PCR, and standard culturing of blood and cerebrospinal fluid (CSF). The setting was a tertiary-care pediatric hospital in Australia, and the participans were 118 children admitted with possible septicemia or meningitis. The main outcome measures—sensitivity, specificity, and positive and negative predictive values—were compared to a “gold standard ” fulfilling clinical and laboratory criteria. For 24 cases of meningococcal disease diagnosed by the gold standard, culturing of blood or CSF was positive for 15 (63%), nested PCR was positive for 21 (88%), and real-time PCR was positive for 23 (96%). The sensitivity, specificity, and positive and negative predictive values of real-time PCR (the most sensitive test) for all specimens were, respectively, 96% (95% confidence interval, 79 to 99%), 100% (95% confidence interval, 96 to100%), 100% (95% confidence interval, 85 to 100%), and 99% (95% confidence interval, 94 to 100%). Of 54 patients with suspected meningococcal disease at admission, 23 had positive PCR results. Only one PCR specimen was positive in a patient thought unlikely to have meningococcal disease at admission. Blood PCR remained positive for 33% of patients tested at up to 72 h. Real-time PCR has high positive and negative predictive values in this clinical setting, with better confirmation of cases than nested PCR. Targeting patients for PCR based on admission criteria appears to be practical, and the test may remain useful for several days after the start of antibiotic administration.

Failure of 500 mg of ceftriaxone to eradicate pharyngeal gonorrhoea, Australia

been occurring since admission. On day 14, the patient developed leucocytosis and blood cultures were drawn, which grew MRSA. The MIC of vancomycin increased to 2 mg/L, with that of daptomycin remaining at 0.38 mg/L. Since the patient continued to be symptomatic, irrigation and debridement was scheduled, but due to surgeon availability issues this was not performed until hospital day 19. A sample was obtained during the procedure and cultured, and on day 22, after .2 weeks of treatment with daptomycin, MRSA grew with a daptomycin MIC of 3 mg/L [daptomycin-non-susceptible S. aureus (DNSSA)]. The primary cause of the daptomycin failure was most likely a delay in incision and drainage of the abscesses. Experimental osteomyelitis models have shown selective resistance with daptomycin monotherapy, 2 which possibly contributed to the resistance in this case. Daptomycin was discontinued and, unfortunately, vancomycin was restarted over the weekend. After the patient became bacteraemic on day 14, we recommended a TEE, which was ordered but not performed until day 23. Lesions were found on the left coronary cusp (LCC) and the tricuspid valve, consistent with endocarditis. Vancomycin was discontinued, since current expert opinion states alternative anti-microbials should be considered when the vancomycin MIC is ≥2 mg/L, due to treatment failures. 3,4 Considering this and the severity of infection in this patient, we turned to salvage therapy options and ceftaroline (600 mg intravenously every 12 h), which had an Etest MIC of 0.5 mg/L, was chosen. Ceftaroline is a fifth-generation cephalosporin with activity against MRSA. Ceftaroline was chosen for a number of reasons. First, it is rapidly bactericidal. Ho et al. 5 reported sterilization in 13 days in a case of endocarditis. Also, the incidence of thrombo-cytopenia with long-term use is low, which was particularly important since our patient had a history of thrombocytopenia secondary to hepatitis. Finally, a literature search revealed a series of case reports showing successful use of ceftaroline in the treatment of MRSA endocarditis 5 and an experimental model demonstrating potential use in osteomyelitis. 6 Subsequent blood cultures drawn on days 29 and 32 were negative. On day 32, a repeat irrigation and debridement was performed. After 37 consecutive days of ceftaroline treatment, a TEE showed resolution of echodensities at the base of the tri-cuspid valve and a stable, fibronodular lesion on the LCC. Ceftaro-line was continued for a total of 44 days, with no further episodes of bacteraemia, leucocytosis or fever, …

Neisseria gonorrhoeae isolates with high-level resistance to azithromycin in Australia

References 1 Ewers C, Stamm I, Pfeifer Y et al. Clonal spread of highly successful ST15-CTX-M-15 Klebsiella pneumoniae in companion animals and horses. J Antimicrob Chemother 2014; 69: 2676–80. 2 Ewers C, Bethe A, Stamm I et al. CTX-M-15-D-ST648 Escherichia coli from companion animals and horses: another pandemic clone combining multiresistance and extraintestinal virulence?. J Antimicrob Chemother 2014; 69: 1224–30. 3 Ewers C, Grobbel M, Stamm I et al. Emergence of human pandemic O25:H4-ST131 CTX-M-15 extended-spectrum-b-lactamase-producing Escherichia coli among companion animals. J Antimicrob Chemother 2010; 65: 651–60. 4 Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals—Third Edition: Approved Standard M31-A3. CLSI, Wayne, PA, USA, 2008.

Increase in meningococcal disease associated with the emergence of a novel ST-11 variant of serogroup C Neisseria meningitidis in Victoria, Australia, 1999-2000

In the years 1999-2000, there was an increase in the incidence of meningococcal disease in Victoria, largely caused by Neisseria meningitidis serogroup C. This change was associated with a shift in age distribution of cases, with relatively more disease appearing in the 15-29 year age group, and with 40/58 serogroup C isolates in 2000 exhibiting a new macrorestriction pattern (pattern A). Thirty-four of 52 pattern A isolates tested displayed the novel phenotype C:2a:P1.4, and were consistently porA VR type P1.7-2,4 by DNA sequencing. Nine of 10 representative pattern A isolates analysed displayed a housekeeping gene allele profile (ST-11) that is characteristic of the electrophoretic type (ET)-15 variant that has caused outbreaks in Canada, the Czech Republic and Greece. Meningococci belonging to the ST-11 complex that were isolated in Victoria prior to 1999 did not display either restriction pattern A or PorA VR type P1.7-2,4.

Anorectal lymphogranuloma venereum in a Melbourne man

We report the first case of anorectal lymphogranuloma venereum (LGV) in a man who has sex with men (MSM) in Australia in the setting of the recent emergence of LGV among MSM in Europe and the USA. A 33-year-old man presented with a 2 month history of mild external anal discomfort. He gave a history of unprotected receptive and insertive anal intercourse with one partner in Europe during the preceding 6 months. No symptoms suggested proctitis and examination revealed two small anal fissures. An anal swab was positive for Chlamydia trachomatis; investigation for other STIs including HIV were negative. On review 6 days later, he was investigated and treated presumptively for LGV. The LGV diagnosis was confirmed by identifying the L2 serovar of C. trachomatis using a genotype test on the original anal specimen. This case is in keeping with the more recent reports of LGV from Europe, and has demonstrated the need for a high index of suspicion for asymptomatic or minimally symptomatic anorectal LGV.

Rapid Determination of Lymphogranuloma Venereum Serovars of Chlamydia trachomatis by Quantitative High-Resolution Melt Analysis (HRMA)

ABSTRACT A quantitative high-resolution melt analysis assay was developed to differentiate lymphogranuloma venereum-causing serovars of Chlamydia trachomatis (L1 to L3) from other C. trachomatis serovars (D to K). The detection limit of this assay is approximately 10 copies per reaction, comparable to the limits of other quantitative-PCR-based methods.

Molecular tests can allow confirmation of invasive meningococcal disease when isolates yield atypical maltose, glucose or gamma-glutamyl peptidase test results.

Summary Analysis of atypical meningococci from invasive disease that either (i) did not produce acid from maltose and glucose or (ii) were gamma‐glutamyl peptidase test negative for porA and porB DNA variable region (VR) type, multilocus sequence type, and for presence of capsule transport gene ctrA, conclusively demonstrated that these are Neisseria meningitidis.