A case of IMP-4-, OXA-421-, OXA-96-, and CARB-2-producing acinetobacter pittii sequence type 119 in Australia

An IMP-4-producing Acinetobacter pittii strain coproducing oxacillinases was isolated from a leg wound of a 67-year-old female patient. Identification to the species level by rpoB and gyrB sequencing and multiplex-PCR-based analysis revealed that the isolate was A. pittii. Whole-genome sequencing of this A. pittii isolate determined the presence of bla(OXA-96), bla(CARB-2), and a novel bla(OXA-421) gene. The position of this novel bla(OXA-421) gene was similar to that of bla(OXA-51) in A. baumannii, downstream of the phosphinothricin N-acetyltransferase gene and upstream of fxsA in the chromosome. This A. pittii isolate was found to belong to sequence type 119 (ST119). Here, we report the first isolation of IMP-4-producing A. pittii ST119 with a novel bla(OXA-421) gene from a patient in Australia and characterize its draft genome

Cefoxitin Plus Doxycycline Versus Clindamycin Plus Gentamicin in Hospitalized Pelvic Inflammatory Disease Patients: An Experience from A Tertiary Hospital

Objective: To compare the length of hospital stay (LOS) and surgical rate in patients hospitalized with pelvic inflammatory disease (PID) who received either cefoxitin plus doxycycline regimen or clindamycin plus gentamicin regimen. Methods: Medical records of patients hospitalized with PID from 2004 to 2011 were reviewed. Study population was women aged 14-40 years old who had a first-time, admitted diagnosis and a discharged diagnosis of PID. Patients who had prior hysterectomy, bilateral salpingectomy and were not sexually active were excluded. The patients received either intravenous cefoxitin (2 grams every 6 hours) plus oral doxycycline (100 mg twice a day) regimen or intravenous clindamycin (900 mg every 8 hours) plus gentamicin (240 mg once daily) regimen. Outcomes of interest were LOS and surgical rate. Results: Of 252 eligible participants, 141 (55.95%) received cefoxitin plus doxycycline and 111 (44.05%) received clindamycin plus gentamicin. The patients receiving cefoxitin plus doxycycline had statistically significant lower age and less number of cases of tubo-ovarian abscess (TOA) (P<0.05). Logistic regression showed the similar LOS and surgical rate in both groups after adjusted with age and TOA. No severe adverse effect was identified in both regimens. Conclusion: Cefoxitin plus doxycycline regimen appears as effective as clindamycin plus gentamicin regimen for treating hospitalized PID patients in terms of LOS, surgical rate and safety profile

Species identification within Acinetobacter calcoaceticus-baumannii complex using MALDI-TOF MS

Acinetobacter baumannii, one of the more clinically relevant species in the Acinetobacter genus is well known to be multi-drug resistant and associated with bacteremia, urinary tract infection, pneumonia, wound infection and meningitis. However, it cannot be differentiated from closely related species such as Acinetobacter calcoaceticus, Acinetobacter pittii and Acinetobacter nosocomialis by most phenotypic tests and can only be differentiated by specific, time consuming genotypic tests with very limited use in clinical microbiological laboratories. As a result, these species are grouped into the A. calcoaceticus-. A. baumannii (Acb) complex. Herein we investigated the mass spectra of 73 Acinetobacter spp., representing ten different species, using an AB SCIEX 5800 MALDI-TOF MS to differentiate members of the Acinetobacter genus, including the species of the Acb complex. RpoB gene sequencing, 16S rRNA sequencing, and gyrB multiplex PCR were also evaluated as orthogonal methods to identify the organisms used in this study. We found that whilst 16S rRNA and rpoB gene sequencing could not differentiate A. pittii or A. calcoaceticus, they can be differentiated using gyrB multiplex PCR and MALDI-TOF MS. All ten Acinetobacter species investigated could be differentiated by their MALDI-TOF mass spectra

Molecular epidemiology and mechanisms of carbapenem resistance of Acinetobacter spp. in Asia and Oceania

Acinetobacter baumannii is emerging as a pathogen that is commonly involved in nosocomial infections. A. baumannii has exhibited the ability to develop multidrug resistance (MDR), including resistance to carbapenems, the last-line class of antibiotics to treat these infections. In particular, MDR A. baumannii International Clone (IC) 2 has disseminated worldwide causing substantial problems in hospitals, including in Asia and Oceania. The global spread of this clonal lineage emphasizes the importance of tracking molecular epidemiology to obtain greater understanding of the population dynamics of A. baumannii. Carbapenem resistance in A. baumannii occurs mainly as a result of acquisition of OXA-type carbapenemase genes, and to some extent by acquisition of metallo--lactamase genes. The acquisition of carbapenemase genes, particularly the bla(OXA-23), bla(OXA-40), and bla(OXA-58), by specific clonal lineages may be one of the attributes responsible for the relative homogeneity of the MDR A. baumannii population

Multiplex PCR to detect the genes encoding naturally occurring oxacillinases in Acinetobacter spp

Objectives: Bacteria of the genus Acinetobacter are increasingly being isolated in hospitals and are recognized as emerging nosocomial pathogens. Species identification is difficult and there is a need for simple molecular methods to differentiate between the species. Naturally occurring oxacillinase genes (bla) have been identified in several Acinetobacter species and their detection by PCR can aid in species identification. The aim of this study was to develop a multiplex PCR to identify intrinsic bla genes (i.e. bla, bla, bla, bla and bla) from Acinetobacter spp. for use as a tool for rapid species identification. Methods: Primers were designed to selectively amplify internal fragments of intrinsic bla from Acinetobacter lwoffii/Acinetobacter schindleri (bla), Acinetobacter johnsonii (bla), Acinetobacter calcoaceticus (bla), Acinetobacter haemolyticus (bla) and Acinetobacter bereziniae (bla). Multiplex PCR was performed in a total of 100 Acinetobacter isolates. Flanking primers were designed for each bla subgroup and products were sequenced. Results: All A. lwoffii, A. schindleri, A. johnsonii, A. calcoaceticus, A. haemolyticus and A. bereziniae isolates were positive for their species-specific amplicons while other Acinetobacter species were negative. Thirty bla novel variants were identified; the majority of these (21/30) were from A. calcoaceticus. ISAba11 was found upstream of bla in four A. haemolyticus isolates, but was not associated with carbapenem resistance. Conclusions: This multiplex PCR specifically detected each of the five different bla subgroups. Therefore, this method has the potential to aid in the identification of these species and monitor the spread of these genes into other Acinetobacter species

Lupinus mutabilis Edible Beans Protect against Bacterial Infection in Uroepithelial Cells

Lupinus mutabilis is a South American herb with edible beans, known to reduce serum glucose levels in diabetic patients. Furthermore, L. mutabilis contains phytochemicals known to decrease bacterial load. Based on the increased urinary tract infections experienced among patients with diabetes, we investigated the effect of L. mutabilis on bladder epithelial cells in the protection of E. coli infection during normal and high glucose concentrations. We did not observe any direct antibacterial effect by L. mutabilis extract. Instead we observed an influence on the host cells, with indirect impact on bacteria and their possibility of causing infection. L. mutabilis extract decreased adhesion to bladder epithelial cells of uropathogenic bacteria, including drug-resistant strains. Moreover, uroplakin1a, involved in adhesion, was downregulated while the antimicrobial peptide RNase 7 was upregulated in L. mutabilis treated cells irrespectively of glucose concentration. This supports an early effect fighting bacteria. Additionally, L. mutabilis prevented bacterial biofilm formation, which is used by bacteria to evade the immune system and antibiotics. In summary, L. mutabilis protects against bacterial infection in uroepithelial cells by preventing adhesion through alteration of the cell surface, increasing antimicrobial peptide expression, and reducing biofilm formation. Together, this promotes bacterial clearance, suggesting that L. mutabilis as extract or as a dietary item can contribute to the prevention of urinary tract infections, which is of importance in an era of increasing antibiotic resistance

Worldwide dissemination of acquired carbapenem-hydrolysing class D β-lactamases in Acinetobacter spp. other than Acinetobacter baumannii

The aim of this study was to identify acquired OXA-type carbapenemases in Acinetobacter spp. other than Acinetobacter baumannii. From a total of 453 carbapenem-susceptible and -resistant Acinetobacter isolates collected worldwide, 23 were positive for bla genes by multiplex PCR. These isolates were identified as Acinetobacter pittii (n = 18), Acinetobacter nosocomialis (n = 2), Acinetobacter junii (n = 1) and Acinetobacter genomic species 14TU/13BJ (n = 2). The bla genes and associated insertion sequence (IS) elements were sequenced by primer walking. In 11 of these isolates, sequencing of the PCR products revealed that they were false-positive for bla. The remaining 12 isolates, originating from Europe, Asia, South America, North America and South Africa, harboured OXA-23 (n = 4), OXA-58 (n = 5), OXA-40-like (n = 1) and OXA-143-like (n = 1); one A. pittii isolate harboured both OXA-23 and OXA-58. IS elements were associated with bla in 10 isolates. OXA multiplex PCR showed a high degree of false-positive results (47.8%), indicating that detection of bla in non-baumannii Acinetobacter spp. should be confirmed using additional methods