Salman Shaheer Ahmed

Carbapenem-resistant Klebsiella pneumoniae sepsis in corticosteroid receipt mice: tigecycline or colistin monotherapy versus tigecycline/colistin combination

Abstract This study compared the effect of monotherapy of colistin, tigecycline, and their combination in sepsis model of mice. OXA-48 producing Carbapenem-resistant Klebsiella pneumoniae (CRKP) strain was used in Balb/c mice. The mice were divided into competent and Methylprednisolone acetate (MPA)-treated groups. Each group was sub-divided into (1) colistin or (2) tigecycline monotherapy and (3) colistin/tigecycline combination therapy. After 3 hours of intraperitoneal bacterial inoculation, antimicrobials were administered, and mice were sacrificed at 24 and 48 hours Time-kill curve study demonstrated that colistin sulphate had early bactericidal activity following re-growth. In competent and MPA-treated groups of mice at 24 hours, bacterial counts in liver samples significantly lowered compared to control, however, there were no statistically differences between monotherapy and combination therapy subgroup. Bacterial count in lung samples of competent group was significantly lesser than control for all three antimicrobial subgroups at 24 hours Colistin plus tigecycline combination therapy was not superior against colistin or tigecycline monotherapy.

Diagnosis of chronic brucellar meningitis and meningoencephalitis: the results of the Istanbul-2 study

No detailed data exist in the literature on the accurate diagnosis of chronic brucellar meningitis or meningoencephalitis. A multicentre retrospective chart review was performed at 19 health centres to determine sensitivities of the diagnostic tests. This study included 177 patients. The mean values of CSF biochemical test results were as follows: CSF protein, 330.64 ± 493.28 mg/dL; CSF/ blood-glucose ratio, 0.35 ± 0.16; CSF sodium, 140.61 ± 8.14 mMt; CSF leucocyte count, 215.99 ± 306.87. The sensitivities of the tests were as follows: serum standard tube agglutination (STA), 94%; cerebrospinal fluid (CSF) STA, 78%; serum Rose Bengal test (RBT), 96%; CSF RBT, 71%; automated blood culture, 37%; automated CSF culture, 25%; conventional CSF culture, 9%. The clinician should use every possible means to diagnose chronic neurobrucellosis. The high seropositivitiy in brucellar blood tests must facilitate the use of blood serology. Although STA should be preferred over RBT in CSF in probable neurobrucellosis other than the acute form of the disease, RBT is not as weak as expected. Moreover, automated culture systems should be applied when CSF culture is needed.

Efficacy of sulbactam and its combination with imipenem, colistin and tigecycline in an experimental model of carbapenem-resistant Acinetobacter baumannii sepsis.

Background: In recent years, multidrug-resistant Acinetobacter baumannii has been reported as an important nosocomial pathogen, and treatment options are limited. The aim of this study was to investigate the additional effect of sulbactam on monotherapy with colistin, tigecycline and imipenem in experimental sepsis with carbapenem-resistant A. baumannii in mice. Methods: Sepsis was developed in 8- to 10-week-old BALB/c mice by an intraperitoneal injection of A. baumannii. Antibiotic was given intraperitoneally 2 h after bacterial inoculation. Each experimental group had 15 mice and was divided into 3 subgroups. Mice were sacrificed at 24, 48 or 72 h. Lung, liver, heart and spleen samples were cultured, and homogenates of lung and liver were used to detect the number of colony-forming units per gram. Bacterial clearance was compared in lung and liver at different time points. Results: Imipenem did not decrease the bacterial load, but the other antibiotics showed significant bactericidal activity compared with the control group, and the combination of imipenem with sulbactam decreased the bacterial load in lung and liver. However, the addition of sulbactam to colistin and tigecycline had no significant effect on bacterial counts. Only the addition of sulbactam to imipenem showed better bactericidal activity compared to imipenem alone. Conclusions: These results suggested that combining sulbactam with tigeycline or colistin does not increase the efficiency of these antibiotics.

Global Epidemiology on Colistin Resistant Acinetobacter baumannii

While colistin remains a last resort agent to treat multi-drug resistant Acinetobacter baumannii, resistance to colistin has been reported throughout the world. The resistance has been attributed to mutations in lipid A biosynthesis genes and point mutation in PmrAB-two component response regulator and sensor kinase system. The emergence of plasmid mediated colistin resistance (mcr-1), in multidrug-resistant enterobacteriaceae raised concerns, though mcr-1 has not yet been reported in A. baumannii. Lately, colistin resistance has been attributed to efflux pumps belonging to RND family. While various reports of emergence of colistin resistance are associated with previous treatment with colistin, other reports concern patients without any prior therapy.

Panton-Valentine leukocidin-positive Staphylococcus aureus: a position statement from the International Society of Chemotherapy

Panton–Valentine leukocidin (PVL), a pore-forming cytotoxic secreted toxin, has been associated with severe Staphylococcus aureus pneumonia and prototypical skin lesions. The reported incidence and prevalence of PVL-positive S. aureus (PVLP-SA) varies globally and suffers from a selective reporting bias towards community-associated methicillin-resistant S. aureus (CA-MRSA)...

Corrigendum to ‘Panton-Valentine Leucocidin (PVL) Staphylococcus aureus a position statement from the International Society of Chemotherapy’ [International Journal of Antimicrobial Agents 51/1 (2018) 16-25]

The authors regret that the author name Silvano Esposito was published incorrectly. The authors would like to apologise for any inconvenience caused.

Establishing molecular microbiology facilities in developing countries

Microbiology laboratories play an important role in epidemiology and infection control programs. Within microbiology laboratories, molecular microbiology techniques have revolutionized the identification and surveillance of infectious diseases. The combination of excellent sensitivity, specificity, low contamination levels and speed has made molecular techniques appealing methods for the diagnosis of many infectious diseases. In a well-equipped microbiology laboratory, the facility designated for molecular techniques remains indiscrete. However, in most developing countries, poor infrastructure and laboratory mismanagement have precipitated hazardous consequences. The establishment of a molecular microbiology facility within a microbiology laboratory remains fragmented. A high-quality laboratory should include both conventional microbiology methods and molecular microbiology techniques for exceptional performance. Furthermore, it should include appropriate laboratory administration, a well-designed facility, laboratory procedure standardization, a waste management system, a code of practice, equipment installation and laboratory personnel training. This manuscript lays out fundamental issues that need to be addressed when establishing a molecular microbiology facility in developing countries.