Rapid identification of capsular serotype K1/K2 Klebsiella pneumoniae in pus samples from liver abscess patients and positive blood culture samples from bacteremia cases via an immunochromatographic strip assay

Background

In Asia, serotype K1/K2 Klebsiella pneumoniae are the major capsular serotypes that cause liver abscess or bacteremia in patients. The purpose of this study was to compare novel immunochromatographic strips (ICSs), which can rapidly detect K. pneumoniae serotypes K1/K2 in clinical samples, to conventional capsular serotyping methods.

Methods

Pus drainage samples from 16 patients with a liver abscess caused by K. pneumoniae, blood samples from 112 positive flagged blood culture bottle and a subsequent single colony in the medium were tested with the ICS. The results were then compared to findings of capsular swelling tests. Samples subjected to the polymerase chain reaction (PCR) analysis were used as reference.

Results

The identification of K. pneumoniae via the traditional bacterial culture from pus samples took 3.4 days on average (ranging from 2.2 to 5.5 days). Further capsular serotyping of K. pneumoniae by the capsular swelling test of pure isolates lasted 5–10 min, and the PCR method took ~ 4 h. As for ICSs, the time for direct identification of the K. pneumoniae capsular serotype K1/K2 in pus was < 4 min (ranging from 2 to 4 min). The results of ICSs were consistent with capsular swelling tests and PCR methods. Testing of 112 blood culture samples and subsequent single colonies in the medium with ICSs yielded consistent results for most samples.

Conclusions

This study indicates that ICSs can rapidly detect K. pneumoniae serotypes K1 and K2 in pus or positive flagged blood culture broth samples within 5 min. Their accuracy is comparable to that of the conventional capsular serotyping methods such as a serum agglutination assay or PCR.

Epidemiological, diagnostic, clinical, and therapeutic aspects of Brucella bacteremia in children in southern Israel: a 7-year retrospective study (2005-2011)

BACKGROUND

Data on the various aspects of brucellosis in children living in southern Israel are missing.

OBJECTIVES

Our aim was to study the epidemiological, microbiological, diagnostic, clinical, therapeutic and outcome features of brucellosis in children <19 years of age in southern Israel during 2005-2011.

PATIENTS AND METHODS

The study population included all patients hospitalized with a diagnosis of brucellosis, established according to a clinical presentation compatible with brucellosis+presence of Brucella bacteremia (BB).

RESULTS

A total of 128 (50.8%) of 252 patients admitted with a diagnosis of brucellosis had BB (all with Brucella melitensis). All patients were of Muslim Bedouin ethnicity. The mean incidence of BB in southern Israel was 16 cases/100,000 Bedouin, with no significant changes during the study period. Overall duration of symptoms before diagnosis was 10.1±10.9 days. Fever at diagnosis was recorded in <20% of the patients. The most frequent symptoms were arthralgia (61.7%), weakness (32.8%), gastrointestinal disturbances (27.3%), myalgia (25%), and headache (18.8%). The main clinical findings included monoarthritis (36.7%), hepatosplenomegaly (25%), lymphadenopathy (17.2%), heart murmur (11.7%), and skin rash (9.4%), respectively. Anemia, leukopenia, thrombocytopenia, and pancytopenia were reported in 17.6%, 29.6%, 12.8%, and 2.3% of the patients, respectively. Twenty-nine (30.5%) patients with BB had serum agglutinin titers ≤1/160 (13, 13.7%%, had titers <1/160). Twenty-seven (93%) of the 29 patients aged 0-4 years were treated with gentamicin and trimethoprim-sulfamethoxazole; a total of 77 (60.2%) patients received gentamicin and doxycycline.

CONCLUSIONS

Childhood brucellosis remains an important public health problem in southern Israel. BB was diagnosed in >50% of the children with brucellosis, and B. melitensis was identified in all cases. Arthralgia, weakness, and gastrointestinal complaints were the most common symptoms, and monoarthritis, hepatosplenomegaly, and lymphadenopathy were the most common clinical findings. A considerable number of patients with BB had undetectable/low serum agglutinin titers, suggesting insufficient reliability on serology alone in diagnosis of brucellosis.