Cephalosporin resistant shigella flexneri from a clinical isolate--a rare finding

Shigellosis is an important public health problem, especially in developing countries. Antibiotic treatment of dysentery aimed at resolving diarrhea or reducing its duration, and to prevent transmission to other close contacts. Isolates with resistance to first line drugs have been reported throughout world, third generation cephalosporins and quinolones are mainstay of treatment. Shigella flexneri resistant to third generation cephalosporins in a clinical isolate is a rare finding, and this has been reported for the first time in Pakistan

Evaluation of predominant Neisseria gonorrhoeae strain types and its correlation with fluoroquinolone resistance in Pakistan

OBJECTIVE: To study the predominant Neisseria gonorrhoeae strain types in Pakistan and to evaluate their correlation with fluoroquinolone resistance. METHOD: A total of 314 strains were collected from 2007-2009. Of these 112 strains were randomly selected for serotyping via the coagglutination technique. Fluoroquinolone susceptibility was checked through the E-test method. Chi square was performed to assess the correlation between the strain type and fluoroquinolone resistance pattern. RESULTS: N. gonorrhoeae isolates were typed in two serogroups and 28 serovars. Serogroup WI comprised 40% (n = 45) whereas WII/WIII was 60% (n = 67). Most commonly isolated serovar belonged to serogroup WI namely Aorst (10%). The other predominant circulating serovars of the serogroup WI were Aost (9%) and Ast (8%) and Bsy (8%), Bopyt (5%) and Bprt (4.5%) in the serogroup WII/III. Fluoroquinolone resistance was 98%, with an MIC of 2 microg/mL in 47%, 4 microg/mL in 36% and \u3e 32 microg/mL in 12% of the isolates. On inferential analysis no significant correlation was observed between fluoroquinolone resistance and any particular serovars. CONCLUSION: A diverse population of N. gonorrhoeae serovars suggesting influx of a variety of gonococcal strains with high fluoroquinolone resistance was identified. This resistance was not associated with any particular serovars, so we speculated inappropriate use of fluoroquinolones in the community to be a major cause. Injudicious fluoroquinolone use in the community should be strongly discouraged to curtail increase in antimicrobial resistance. Furthermore, continuous surveillance of prevalent serovars will be critical to assess genetic alterations of endemic and imported strains to design effective disease control measures

Increased isolation of vibrio cholerae O1 serotype inaba over serotype ogawa in Pakistan

Although the predominant Vibrio cholerae serotype in Pakistan is Ogawa and serotype Inaba is rare, there has been a significant increase in the isolation of Inaba in our referral laboratory in Karachi. This paper reports this observation and further analysis of previous cholera data from 1993 to 2005 to assess the trend of occurrence and resistance pattern of V. cholerae strains. From January to September 2005, 245/3292 (7.4%) specimens yielded growth of V. cholerae. Of these, 243 were serotype Inaba, outnumbering serotype Ogawa. This recent Inaba strain is 100% resistant to cotrimoxazole, 3% resistant to chloramphenicol and not resistant to ampicillin, tetracycline and ofloxacin. This sensitivity pattern is almost similar to that of the previous predominant serotype Ogawa

Evaluation of prevalence of low and high level mupirocin resistance in methicillin resistant Staphylococcus aureus isolates at a tertiary care hospital

OBJECTIVE: To evaluate the trend of mupirocin resistance in MRSA, isolated at the Clinical Microbiology Laboratory of a tertiary care hospital. METHODS: A total of 200 MRSA strains recovered over a 2 year period from various body sites were tested using the 5 and 200 microg discs of mupirocin to detect its resistance. RESULTS: High level and low level mupirocin resistance were detected in zero and 1% of MRSA strains, respectively. Resistance to other non beta lactam antibiotics was also high. No MRSA strains were found to be resistant to vancomycin and tegicycline. CONCLUSION: Mupirocin resistance was found to be very low among local clinical isolates of MRSA. Its judicious use to decolonize nasal carriers should be promoted among hospitalized patients to avoid further transmission and infections due to prevalent endemic MRSA strains in any health care setting. Concomitantly, regular surveillance and effective infection control initiatives are desirable to reduce the incidence of health care associated infections due to MRSA and also of mupirocin resistance

Antimicrobial activity of tigecycline against nosocomial pathogens in Pakistan: a multicenter study

OBJECTIVE: To measure the in-vitro activity of various antibiotics including tigecycline against Gram negative and positive nosocomial aerobic isolates. METHODS: A total of 430 clinical isolates of both Gram positive (143) and negative (287) aerobic bacteria were used from 3 centres during the year 2006 and 2007. Minimum inhibitory concentration (MIC) was determined using broth micro dilution panels. Antibiotic resistance was interpreted using CLSI guidelines. RESULTS: Most of the isolates were resistant to more than one drug. Resistance to tigecycline was not found. Tigecycline (1 microg/ml) had low MIC against organisms tested. CONCLUSION: This data indicates that tigecycline, a new drug in its class, has broad-spectrum in-vitro activity against both Gram negative and positive nosocomial isolates. Therefore, it may be a suitable drug to be used for the treatment of highly resistant nosocomial infections

Frequency of isolation of shigella serogroups/serotypes and their antimicrobial susceptibility pattern in children from slum areas in Karachi

Objectives: To assess the frequency of serogroups and serotypes, as well as the antimicrobial susceptibility pattern of Shigella species isolated from known cases of diarrhoea and dysentery from Karachi, Pakistan. Methods: A cross-sectional study was conducted between January 2002 and March 2003 at Aga Khan University on stool samples received from children with diarrhoea and dysentery from four low socio-economic areas (Sultanabad, Rehri Goth, Hijrat and Sherpao colony) of Karachi. Stool samples yielding growth of Shigella species, were further identified for serotypes by slide agglutination. Antibiotics susceptibility was performed by Kirby Bauer disk diffusion methodResults: Out of 4688 stool samples received, 193 (4.1%) were positive for Shigella species. Shigella flexneri was the predominant serogroup (58%) followed by Shigella sonnei (16%), Shigella boydii (15%) and Shigella dysentriae being the least common (11%). A number of serotypes were isolated in each serogroup, 8 serotypes in S. flexneri, 8 serotypes in S. dysenteriae, 9 serotypes in S. boydii, and Phase 1& 2 were found in S. sonnei. 17% isolates remained non-serotypeable. All isolates were susceptible to Ofloxacin and Ceftriaxone, high rate of resistance was observed in Cotrimoxazole (87.75%) and Ampicillin (55.5%). Emerging resistance against Nalidixic acid (39%) was observed.Conclusion: Shigella still accounts for a significant proportion of bacillary dysentery in many tropical and subtropical countries. Serotype identification can help in devising strategies such as development of effective vaccine for controlling this problem. Increasing antibiotic resistance against commonly prescribed drugs signify that treatment options have become difficult in cases of severe dysentery (JPMA 55:184;2005)

Frequency and sensitivity pattern of extended spectrum beta lactamase producing isolates in a tertiary care hospital laboratory of Pakistan

Objective: To determine frequency, distribution and sensitivity pattern of Extended-Spectrum ß Lactamase (EBSL) producing organism at a tertiary care hospital in Pakistan. Methods: All members of enterobacteriacae isolated between April and August 2002 were studied. Isolates were speciated according to standard biochemical tests. Susceptibility testing was performed by Kirby-Bauer method. ESBL was detected using double disc method using cefotaxime versus cefotaxime plus clavulanate according to NCCLS. Statistical analysis was performed by SPSS version 10. Test of significance were calculated using chi-square test. Results: During the study period, 1137/2840 (40%) of the isolates tested were found to be ESBL producing. ESBL positivity was detected in 50% Enterobacter sp., 41% E.coli and 36% K.pneumoniae. ESBL production was noted in 52% of nosocomial isolates tested (415/799). ESBL was more frequent in patients at the extremes of ages (under 5 years and more than 60 years). Cross-resistance to non-beta lactam antibiotics (flouoroquinolones, aminoglycosides and co-trimoxazole) was also more frequent in ESBL producing organisms Conclusion: A high frequency of ESBL positivity amongst our isolates is documented which is alarming in low-income settings where expensive second line agents are unavailable. Our data supports urgent need for regular screening and surveillance for these organisms (JPMA 55:436;2005)

Cryptococcus neoformans and streptococcus pneumoniae co-infection in post-traumatic meningitis in a patient with unknown HIV status

Meningitis is a serious disease associated with considerable morbidity and mortality. Mixed meningeal infections due to bacteria and fungi are exceptionally rare. Here we report a case of meningeal co-infection with cryptococcus neoformans and streptococcus pneumoniae in a patient with unknown human immunodeficiency virus status. Because of the rarity of such cases, stringent screening of every cerebrospinal fluid specimen to exclude the presence of multiple pathogens is imperative. Assessment of patients for immunodeficiencies in case of isolation of an opportunistic organism like cryptococcus is also needed