High rate of non-susceptibility to metronidazole and clindamycin in anaerobic isolates: Data from a clinical laboratory from Karachi, Pakistan.

Due to increasing resistance amongst anaerobic pathogens periodic surveillance of resistance has been recommended in regional/local settings. Anaerobic antimicrobial susceptibility testing is not routinely performed in many laboratories in Pakistan, hence absence of local data may lead to inappropriate empirical therapy in serious cases. 121 clinically significant anaerobic strains (26/121; 21% bacteremic isolates) were isolated and saved from 2010 to 2011. Susceptibility testing against metronidazole, clindamycin, co-amoxiclav, meropenem, piperacillin/tazobactam, linezolid and gatifloxacin was performed by determining minimum inhibitory concentrations (MICs). A high proportion of non-susceptible strains to metronidazole (10% of 121 isolates) and clindamycin (12% of 121 isolates) was seen, most noticeable in Bacteroides fragilis. Three Bacteroides species strains were non-susceptible to both metronidazole and clindamycin. One strain of Clostridium species was fully resistant to metronidazole and had intermediate resistance to clindamycin. No resistance to any of the other tested antibiotics was seen. Resistance to metronidazole was higher in bacteremic vs. non bacteremic isolates (p = value 0.07). In our setting where there is a high usage of empirical metronidazole and clindamycin for the treatment of serious anaerobic infections clinicians should be aware of increased resistance to these agents. Periodic surveillance of resistance to anti-anaerobic drugs especially metronidazole and clindamycin should be performed to generate antibiogram and guide appropriate empiric therapy.

Mixed Salmonella infection: a report of two cases from the Aga Khan University Hospital, Karachi.

Enteric fever remains a major health problem in the developing world, including Pakistan. Poor sanitation and hygienic conditions are the major predisposing factors. Salmonella infection with different strains in the same patient has rarely been reported previously. We are reporting two cases of bacteraemia with simultaneous detection of two strains of Salmonella in a single episode of infection. In both the cases, 2 different serotypes of Salmonella were causing bacteraemia leading to fever. In highly endemic area, one must be aware of mixed Salmonella infections as inappropriate diagnosis of such infections may lead to treatment failure.

In vitro susceptibility of typhoidal Salmonellae against newer antimicrobial agents: a search for alternate treatment options.

OBJECTIVES: To determine the minimum inhibitory concentrations (MICs) of ceftriaxone, azithromycin, pefloxacin, cefipime and imipenem for Salmonella Typhi (S. Typhi) and Paratyphi. METHODS: One hundred and fifty four isolates of Salmonella Typhi and S. Paratyphi A, B and C growing in blood culture were selected. MICs of ceftriaxone, azithromycin, pefloxacin, cefipime and imipenem were performed by agar dilution method as recommended by clinical laboratory standard institutes. RESULTS: MIC90 of azithromycin and pefloxacin was 8 microg/ml, cefipime was 0.06 microg/ml and imipenem was 0.5 microg/ml. None of the strains were found to be resistant to ceftriaxone but 3 isolates showed higher MIC value of 2 microg/ml. CONCLUSION: Azithromycin appears a suitable alternate for the treatment of typhoid in the community. Imipenem and cefipime are good options in complicated cases to be treated in hospital settings. Pefloxacin cannot be used as MICs are higher. Presence of isolates with higher MIC of ceftriaxone is serious and stresses upon continuous laboratory surveillance to guide clinicians appropriately.

Comparison of chromogenic urinary tract infection medium with cysteine lactose electrolyte deficient media in a resource limited setting.

OBJECTIVES: To compare the chromogenic UTI medium (CUM) with cysteine lactose electrolyte deficient medium (CLED) in terms of isolation of uropathogens, turnaround time and cost. METHODS: A total of 251 urine samples were selected and inoculated on both CLED and CUM, growth was observed after 24 and 48 hours of incubation. Isolates were identified by colony's colour and biochemical tests. Turnaround time for identification and cost was calculated till final identification of microorganisms. RESULTS: A discrepancy in isolation was observed in seven samples with growth on CUM in 24 hours while in 48 hours on CLED. There was 100% agreement in identification by both media. Almost 50% samples were identified within 24 hours by using CUM in contrast to CLED where most samples were identified in 48 hours. Total number of reagents used and total cost for processing of a specimen including technologist and consultant time by using CUM is significantly low in comparison to CLED. CONCLUSION: CUM can replace CLED as a primary isolation media for urine culture in clinical laboratories in Pakistan as it is user friendly, facilitates early reporting and saves cost.

Human linker histones: interplay between phosphorylation and O-ß-GlcNAc to mediate chromatin structural modifications.

Eukaryotic chromatin is a combination of DNA and histone proteins. It is established fact that epigenetic mechanisms are associated with DNA and histones. Initial studies emphasize on core histones association with DNA, however later studies prove the importance of linker histone H1 epigenetic. There are many types of linker histone H1 found in mammals. These subtypes are cell specific and their amount in different types of cells varies as the cell functions. Many types of post-translational modifications which occur on different residues in each subtype of linker histone H1 induce conformational changes and allow the different subtypes of linker histone H1 to interact with chromatin at different stages during cell cycle which results in the regulation of transcription and gene expression. Proposed O-glycosylation of linker histone H1 promotes condensation of chromatin while phosphorylation of linker histone H1 is known to activate transcription and gene regulation by decondensation of chromatin. Interplay between phosphorylation and O-ß-GlcNAc modification on Ser and Thr residues in each subtype of linker histone H1 in Homo sapiens during cell cycle may result in diverse functional regulation of proteins. This in silico study describes the potential phosphorylation, o-glycosylation and their possible interplay sites on conserved Ser/Thr residues in various subtypes of linker histone H1 in Homo sapiens.