Screening for urinary tract infection with the Sysmex UF-1000i urine flow cytometer.

The diagnosis of urinary tract infection (UTI) by urine culture is time-consuming and can produce up to 60 to 80% negative results. Fast screening methods that can reduce the necessity for urine cultures will have a large impact on overall turnaround time and laboratory economics. We have evaluated the detection of bacteria and leukocytes by a new urine analyzer, the UF-1000i, to identify negative urine samples that can be excluded from urine culture. In total, 1,577 urine samples were analyzed and compared to urine culture. Urine culture showed growth of ≥10(3) CFU/ml in 939 samples (60%). Receiver operating characteristics (ROC) curves and ROC decision plots were been prepared at three different gold standard definitions of a negative urine culture: no growth, growth of bacteria at <10(4) CFU/ml, and growth of bacteria at <10(5) CFU/ml. Also, the reduction in urine cultures and the percentage of false negatives were calculated. At the most stringent gold standard definition of no growth, a chosen sensitivity of 95% resulted in a cutoff value of 26 bacteria/µl, a specificity of 43% and a reduction in urine cultures of only 20%, of which 14% were false negatives. However, at a gold standard definition of <10(5) CFU/ml and a sensitivity of 95%, the UF-1000i cutoff value was 230 bacteria/µl, the specificity was 80%, and the reduction in urine cultures was 52%, of which 0.3% were false negatives. The applicability of the UF-1000i to screen for negative urine samples strongly depends on population characteristics and the definition of a negative urine culture. In our setting, however, the low workload savings and the high percentage of false-negative results do not warrant the UF-1000i to be used as a screening analyzer.

Group-A-streptococcal meningitis in a 7-year-old child--a rare pathogen in a non-immune compromised patient.

A case is presented of meningitis in a 7-year-old female child caused by Group A streptococcus (GAS), a rare bacterial cause of meningitis, with a high rate of morbidity (46%) and mortality (10%). GAS is susceptible for empiric antibiotic therapy aimed at the most prevalent pathogens of meningitis. As GAS meningitis is typically associated with ear-nose-throat (ENT) infections, specific search for a reservoir is advised. Bacterial typification often demonstrates M-protein gene sequence type (EMM type) 1.0 associated with upper respiratory tract infections and also severe, invasive GAS infections. Follow-up investigation including neurologic developmental status and audiologic testing is necessary. Although GAS is a very uncommon cause of acute bacterial meningitis in children, high morbidity and mortality have been reported. Being associated with ENT infections, a search for a GAS reservoir is proposed. GASs are susceptible for common empiric antibiotic therapies in meningitis. Follow-up investigation is necessary.

Group-A-streptococcal meningitis in a 7-year-old child--a rare pathogen in a non-immune compromised patient.

A case is presented of meningitis in a 7-year-old female child caused by Group A streptococcus (GAS), a rare bacterial cause of meningitis, with a high rate of morbidity (46%) and mortality (10%). GAS is susceptible for empiric antibiotic therapy aimed at the most prevalent pathogens of meningitis. As GAS meningitis is typically associated with ear-nose-throat (ENT) infections, specific search for a reservoir is advised. Bacterial typification often demonstrates M-protein gene sequence type (EMM type) 1.0 associated with upper respiratory tract infections and also severe, invasive GAS infections. Follow-up investigation including neurologic developmental status and audiologic testing is necessary. Although GAS is a very uncommon cause of acute bacterial meningitis in children, high morbidity and mortality have been reported. Being associated with ENT infections, a search for a GAS reservoir is proposed. GASs are susceptible for common empiric antibiotic therapies in meningitis. Follow-up investigation is necessary.

16S rRNA mutation-mediated tetracycline resistance in Helicobacter pylori.

Most Helicobacter pylori strains are susceptible to tetracycline, an antibiotic commonly used for the eradication of H. pylori. However, an increase in incidence of tetracycline resistance in H. pylori has recently been reported. Here the mechanism of tetracycline resistance of the first Dutch tetracycline-resistant (Tet(r)) H. pylori isolate (strain 181) is investigated. Twelve genes were selected from the genome sequences of H. pylori strains 26695 and J99 as potential candidate genes, based on their homology with tetracycline resistance genes in other bacteria. With the exception of the two 16S rRNA genes, none of the other putative tetracycline resistance genes was able to transfer tetracycline resistance. Genetic transformation of the Tet(s) strain 26695 with smaller overlapping PCR fragments of the 16S rRNA genes of strain 181, revealed that a 361-bp fragment that spanned nucleotides 711 to 1071 was sufficient to transfer resistance. Sequence analysis of the 16S rRNA genes of the Tet(r) strain 181, the Tet(s) strain 26695, and four Tet(r) 26695 transformants showed that a single triple-base-pair substitution, AGA(926-928)-->TTC, was present within this 361-bp fragment. This triple-base-pair substitution, present in both copies of the 16S rRNA gene of all our Tet(r) H. pylori transformants, resulted in an increased MIC of tetracycline that was identical to that for the Tet(r) strain 181.